Epilepsy surgery indications

Epilepsy surgery indications

Epilepsy surgery is an established safe and effective treatment for selected candidates with drug-resistant epilepsy. In a opinion piece, Hale et al. from the Children’s of Alabama, Great Ormond Street Hospital, Nemours Children’s Hospital outlined the clinical and experimental evidence for selectively considering epilepsy surgery prior to drug resistance. The rationale for expedited surgery is based on the observations that, 1) a high proportion of patients with lesional epilepsies (e.g. focal cortical dysplasia, epilepsy associated tumours) will progress to drug-resistance, 2) surgical treatment of these lesions, especially in non-eloquent areas of brain, is safe, and 3) earlier surgery may be associated with better seizure outcomes. Potential benefits beyond seizure reduction or elimination include less exposure to anticonvulsants (ASM), which may lead to improved developmental trajectories in children and optimize long-term neurocognitive outcomes and quality of life. Further, there exists emerging experimental evidence that brain network dysfunction exists at the onset of epilepsy, where continuing dysfunctional activity could exacerbate network perturbations. This in turn could lead to expanded seizure foci and contribution to the comorbidities associated with epilepsy. Taken together, they rationalize that epilepsy surgery, in carefully selected cases, may be considered prior to drug resistance. Lastly, they outlined the path forward, including the challenges associated with developing the evidence base and implementing this paradigm into clinical care 1).

20% of patients continue to have seizures despite aggressive medical management with antiepileptic drugs AEDs. Many of these patients may be candidates for surgical procedures to control their seizures 2).

Seizure disorder must be severe, medically refractory with satisfactory trials of tolerable medication for at least 1 year, and disabling to the patient. Medically refractory epilepsy is usually considered two attempts of high-dose monotherapy with two distinct AEDs, and one attempt at polytherapy.

The three general categories of patients suitable for seizure surgery have 3):

  1. partial seizures

a) temporal origin: the largest group of surgical candidates (especially mesial temporal lobe epilepsy (MTLE) which is often medically refractory)

b) extratemporal origin

  1. symptomatic generalized seizures: e.g. Lennox-Gastaut syndrome.

  2. unilateral, multifocal epilepsy associated with infantile hemiplegia syndrome.

The goal is to eliminate seizures or significantly reduce seizure burden.

In most state-of-the-art epilepsy units, resective epilepsy surgery is currently the standard treatment for intractable epilepsy. Generally, the success rate, defined as a seizure-free status or Engel class I, is between 62% and 71%, as compared to 14% in non-operated cases 4) 5).

Generally, surgery is considered in patients whose seizures cannot be controlled by adequate trials of two different medications. Epilepsy surgery has been performed for more than a century, but its use dramatically increased in the 1980s and ’90s, reflecting its efficacy in selected patients.

Patients with comorbid psychosis and temporal lobe drug-resistant epilepsy may benefit from epilepsy surgery under close psychiatric supervision 6).

Epilepsy surgery is an effective and safe therapeutic modality in childhood. In children with extratemporal epilepsy, more careful interpretation of clinical and investigative data is needed to achieve favorable seizure outcome 7).

see Tuberous sclerosis complex surgery.


Hale AT, Chari A, Scott RC, Cross JH, Rozzelle CJ, Blount JP, Tisdall MM. Expedited epilepsy surgery prior to drug resistance in children: a frontier worth crossing? Brain. 2022 Jul 27:awac275. doi: 10.1093/brain/awac275. Epub ahead of print. PMID: 35883201.

Engel JJ. Surgery for Seizures. N Engl J Med. 1996; 334:647–652

National Institutes of Health Consensus Development Conference. Surgery for Epilepsy. JAMA. 1990; 264:729–733

Edelvik A, Rydenhag B, Olsson I, et al. Long-term outcomes of epilepsy surgery in Sweden: a national prospective and longitudinal study. Neurology 2013;81:1244–51.

Sarkis RA, Jehi L, Najm IM, et al. Seizure outcomes following multilobar epilepsy surgery. Epilepsia 2012;53:44–50.

D’Alessio L, Scévola L, Fernandez Lima M, Oddo S, Solís P, Seoane E, Kochen S. Psychiatric outcome of epilepsy surgery in patients with psychosis and temporal lobe drug-resistant epilepsy: A prospective case series. Epilepsy Behav. 2014 Jul 15;37C:165-170. doi: 10.1016/j.yebeh.2014.06.002. [Epub ahead of print] PubMed PMID: 25036902.

Kim SK, Wang KC, Hwang YS, Kim KJ, Chae JH, Kim IO, Cho BK. Epilepsy surgery in children: outcomes and complications. J Neurosurg Pediatr. 2008 Apr;1(4):277-83. doi: 10.3171/PED/2008/1/4/277. PubMed PMID: 18377302.

Lumbar decompression surgery for spinal canal stenosis outcome

Lumbar decompression surgery for spinal canal stenosis outcome

Lumbar laminectomy, represents the standard operative treatment for lumbar spinal stenosis, but this procedure is often combined with fusion surgery. It is still discussed whether minimal-invasive decompression procedures are sufficient and if they compromise spinal stability as well.

Decompression of lumbar spinal stenosis without fusion led to a significant and similar reduction of back pain and leg pain in a short-term and a long-term follow-up group. Patients without previous surgery benefited significantly better, whereas patients with previous decompression benefited regarding back pain, especially for long-term follow-up with a clear trend in favor of leg pain 1).

Currently, there is interest in minimally invasive surgery and various technical modifications of decompressive lumbar laminectomy without fusion.

Particularly, depression has been shown to be associated with less improvement following lumbar fusion surgery 2) 3) 4) 5) 6) 7) 8).

Karp et al. 9) reviewed 158 patients who underwent epidural spinal injections for low-back pain with or without radiculopathy. These investigators found that depression and sleep disturbance were prognostic of worse Patient-Reported Outcome Measurement Information System (PROMIS) outcomes following epidural spinal injections.

Hägg et al. 10) performed a randomized controlled trial of 264 patients with severe chronic low-back pain who underwent either surgical or nonsurgical treatment, and assessed the impact of underlying affective disorders. They found that baseline depression correlated with worse outcomes following both operative and nonoperative treatment.

Interestingly, they also observed that depressed patients tended to have better outcomes with nonoperativecare, whereas nondepressed patients tended to have better outcomes with fusion.

In the study of Lubelski et al. 11) found that worsening depression (as measured by the PHQ-9) independently significantly predicted worse EQ-5D index outcomes following conservative treatment for LSS (p = 0.0002). This effect was most evident when comparing patients with severe depression, who improve 0.14 points less than those with no depression. This difference exceeds the MCID and confirms that depression is a poor prognostic factor for QOL improvement following nonoperative treatment for LSS. Further investigation is needed to determine whether treatment of depression prior to conservative or surgical management of LSS will improve posttreatment QOL outcomes. There are several limitations that should be considered when interpreting the results. Multiple treating physicians were included, and factors such as participation in physical therapy, treatment with NSAIDs, opioid medications and other nonsurgical treatments varied by practitioner and patient; this increases the variability, but also improves the generalizability.

They adjusted for the increased variability by using the random effect in the regression models. Many patients were also lost to follow-up at the 4-month evaluation.

The cohorts were similar for most characteristics; however, there were statistically significant, albeit small differences for estimated percent below poverty threshold and median income by zip code. The analysis is only valid for patients who did follow-up assessments at these time points. Additionally, this was a retrospective study with a relatively short follow-up period.

Prospectively designed studies with longer follow-up are needed to further validate the findings. Nonetheless, this is the largest study investigating the correlation between depression and QOL outcomes following conservative management of LSS.

Lubelski et al. have used the validated PHQ-9 measure of depression and have found a statistically and clinically significant impact on EQ-5D index outcomes.

The results of this study suggest that depressed patients with LSS have significantly less improvement following conservative management compared with nondepressed patients. Both physicians and surgeons who treat patients with LSS should consider using validated questionnaires such as the PHQ-9 for pretreatment evaluation of depression, to better assess the likelihood of success following treatment. Further investigation is needed to evaluate the effect of depression treatment prior to management of the spinal disorder. Future prospective studies with longer follow-up intervals may be useful in further evaluating the QOL outcomes in this patient population 12).

In cases of lumbar spinal stenosis (LSS) treated with surgical decompression, a postoperative magnetic resonance imaging (MRI) is sometimes required. In the experience of a study, the obtained decompression observed on early postoperative MRI tends to be disappointing compared to the decompression achieved intraoperatively. This raises the question of whether the early postoperative MRI, performed after lumbar decompression, is a fair representation of the ‘real’ decompression. A study investigated the correlation between intraoperative and postoperative measurements of the lumbar spinal canal.

Surgical decompression of the spinal canal effectively decreases the compression of the dural sac. However, early postoperative MRI after lumbar decompression does not adequately represent the decompression achieved intraoperatively 13).

Back pain improvement

Through the 1st postoperative year, patients with lumbar stenosis-without spondylolisthesis, scoliosis, or sagittal malalignment-and clinically significant back pain improved after decompression-only surgery 14).

The most common surgical method currently used is lumbar laminectomy, with complete decompression; this technique has a 5-year follow-up effective rate of 81.6% 15).

Apart from acute complications such as hematoma and infections, same-level recurrent lumbar stenosis and adjacent-segment disease (ASD) are factors that can occur after index lumbar spine surgery.

While looking for predictors of revision surgery due to re-stenosis, instability or same/adjacent segment disease none of these were found. Within our cohort no significant differences concerning demographic, peri-operative and radiographic data of patients with or without revision wer noted. Patients, who needed revision surgery were older but slightly healthier while more likely to be male and smoking. Surprisingly, significant differences were noted regarding the distribution of intraoperative and early postoperative complications among the 6 main surgeons while these weren’t obious within the intial index group of late revisions 16).

A systematic review was conducted using MEDLINE for literature published through December 2014. The first question focused on the effectiveness of lumbar spine surgery for symptomatic lumbar spinal stenosis in elderly patients. The second question focused on safety of surgical intervention on this elderly population with emphasis on perioperative complication rates.

Review of 11 studies reveals that the majority of elderly patients exhibit significant symptomatic improvement, with overall benefits observed for pain (change visual analog scale4.4 points) and disability (change Oswestry Disability Index 23 points). Review of 11 studies reveals that perioperative complications were infrequent and acceptable with pooled estimates of mortality (0.5%), inadvertent durotomy (5%), and wound infection (2%). Outcomes seem less favorable with greater complication rates among patients with diabetesor obesity.

Based on largely low-quality, retrospective evidence, Shamji et al. recommend that elderly patients should not be excluded from surgical intervention for symptomatic lumbar spinal stenosis 17).

Fusion Is Not a Safeguard to Prevent Revision Surgery in Lumbar Spinal Stenosis 18).

A cohort study showed no significant association between the type of index operation for Degenerative Lumbar Spinal Stenosis-decompression alone or fusion-and the need for revision surgery or the outcomes of pain, disability, and quality of life among patients after 3 years. Number of revision operations was associated with more pain and worse quality of life 19).


Geiger MF, Bongartz N, Blume C, Clusmann H, Müller CA. Improvement of Back and Leg Pain after Lumbar Spinal Decompression without Fusion. J Neurol Surg A Cent Eur Neurosurg. 2018 Dec 5. doi: 10.1055/s-0038-1669473. [Epub ahead of print] PubMed PMID: 30517963.

Aalto TJ, Malmivaara A, Kovacs F, Herno A, Alen M, Salmi L, et al: Preoperative predictors for postoperative clinical outcome in lumbar spinal stenosis: systematic review. Spine (Phila Pa 1976) 31:E648–E663, 2006

Adogwa O, Parker SL, Shau DN, Mendenhall SK, Aaronson OS, Cheng JS, et al: Preoperative Zung Depression Scale predicts outcome after revision lumbar surgery for adjacent segment disease, recurrent stenosis, and pseudarthrosis. Spine J 12:179–185, 2012

Adogwa O, Parker SL, Shau DN, Mendenhall SK, Bydon A, Cheng JS, et al: Preoperative Zung depression scale predicts patient satisfaction independent of the extent of improvement after revision lumbar surgery. Spine J 13:501–506, 2013

Arpino L, Iavarone A, Parlato C, Moraci A: Prognostic role of depression after lumbar disc surgery. Neurol Sci 25:145– 147, 2004

Chaichana KL, Mukherjee D, Adogwa O, Cheng JS, McGirt MJ: Correlation of preoperative depression and somatic perception scales with postoperative disability and quality of life after lumbar discectomy. J Neurosurg Spine 14:261– 267, 2011

Sinikallio S, Aalto T, Airaksinen O, Herno A, Kröger H, Viinamäki H: Depressive burden in the preoperative and early recovery phase predicts poorer surgery outcome among lumbar spinal stenosis patients: a one-year prospective follow-up study. Spine (Phila Pa 1976) 34:2573–2578, 2009

Trief PM, Grant W, Fredrickson B: A prospective study of psychological predictors of lumbar surgery outcome. Spine (Phila Pa 1976) 25:2616–2621, 2000

Karp JF, Yu L, Friedly J, Amtmann D, Pilkonis PA: Negative affect and sleep disturbance may be associated with response to epidural steroid injections for spine-related pain. Arch Phys Med Rehabil 95:309–315, 2014

Hägg O, Fritzell P, Ekselius L, Nordwall A: Predictors of outcome in fusion surgery for chronic low back pain. A report from the Swedish Lumbar Spine Study. Eur Spine J 12:22–33, 2003
11) , 12)

Lubelski D, Thompson NR, Bansal S, Mroz TE, Mazanec DJ, Benzel EC, Khalaf T. Depression as a predictor of worse quality of life outcomes following nonoperative treatment for lumbar stenosis. J Neurosurg Spine. 2015 Mar;22(3):267-72. doi: 10.3171/2014.10.SPINE14220. Epub 2014 Dec 19. PubMed PMID: 25525957.

Schenck C, van Susante J, van Gorp M, Belder R, Vleggeert-Lankamp C. Lumbar spinal canal dimensions measured intraoperatively after decompression are not properly rendered on early postoperative MRI. Acta Neurochir (Wien). 2016 May;158(5):981-8. doi: 10.1007/s00701-016-2777-5. Epub 2016 Mar 23. PubMed PMID: 27005673; PubMed Central PMCID: PMC4826663.

Crawford CH 3rd, Glassman SD, Mummaneni PV, Knightly JJ, Asher AL. Back pain improvement after decompression without fusion or stabilization in patients with lumbar spinal stenosis and clinically significant preoperative back pain. J Neurosurg Spine. 2016 Nov;25(5):596-601. PubMed PMID: 27285666.

Bouras T, Stranjalis G, Loufardaki M, Sourtzis I, Stavrinou LC, Sakas DE. Predictors of long-term outcome in an elderly group after laminectomy for lumbar stenosis. J Neurosurg Spine. 2010;59:329–34.

Melcher C, Paulus AC, Roßbach BP, Gülecyüz MF, Birkenmaier C, Schulze-Pellengahr CV, Teske W, Wegener B. Lumbar spinal stenosis – surgical outcome and the odds of revision-surgery: Is it all due to the surgeon? Technol Health Care. 2022 Jun 10. doi: 10.3233/THC-223389. Epub ahead of print. PMID: 35754243.

Shamji MF, Mroz T, Hsu W, Chutkan N. Management of Degenerative Lumbar Spinal Stenosis in the Elderly. Neurosurgery. 2015 Oct;77 Suppl 4:S68-74. doi: 10.1227/NEU.0000000000000943. PubMed PMID: 26378360.

Austevoll IM, Ebbs E. Fusion Is Not a Safeguard to Prevent Revision Surgery in Lumbar Spinal Stenosis. JAMA Netw Open. 2022 Jul 1;5(7):e2223812. doi: 10.1001/jamanetworkopen.2022.23812. PMID: 35881401.

Ulrich NH, Burgstaller JM, Valeri F, Pichierri G, Betz M, Fekete TF, Wertli MM, Porchet F, Steurer J, Farshad M; Lumbar Stenosis Outcome Study Group. Incidence of Revision Surgery After Decompression With vs Without Fusion Among Patients With Degenerative Lumbar Spinal Stenosis. JAMA Netw Open. 2022 Jul 1;5(7):e2223803. doi: 10.1001/jamanetworkopen.2022.23803. PMID: 35881393.

Spontaneous intracerebral hemorrhage surgery

Spontaneous intracerebral hemorrhage surgery

Based on the MIMIC-III database, Yi et al. from the Guangzhou Overseas Chinese Hospital firstly described the dissimilarities in survival probabilitymortality, and neurological recovery among mainstream treatments for intracerebral hemorrhage; secondly, patient classification was determined by important clinical features; and outcome variations among treatment groups were compared. The 28-day, 90-day, and in-hospital mortality in the craniotomy group were significantly lower than minimally invasive surgery (MIS) and non-surgical group patients; and, the medium/long-term mortality in the MIS group was significantly lower than the non-surgical group. The craniotomy group positively correlated with short-term GCS recovery compared with the MIS group; no difference existed between the non-surgical and MIS groups. The craniotomy group’s 90-day survival probability and short-term GCS recovery were superior to the other two treatments in the subgroups of first GCS 3-12; this tendency also presented in the MIS group over the non-surgical group. For milder patients (first GCS > 12), the three treatment regimens had a minimal effect on patient survival, but the non-surgical group showed an advantage in short-term GCS recovery. Craniotomy patients have lower mortality and a better short-term neurological recovery in an ICH population, especially in short-to-medium term mortality and short-term neurological recovery over MIS patients. In addition, surgical treatment is recommendable for patients with a GCS ≤ 12. 1).


see Intracerebral hemorrhage treatment randomized controlled trials.

A better understanding of the pathophysiology of intracerebral hemorrhage (ICH) has led to the identification of several new mechanisms of injury that could be potential therapeutic targets 2).

Minimally invasive surgery (MIS) for the treatment of ICH is the main clinical method that is currently used, despite the lack of large-scale, clinical, multi-center, randomized controlled trials 3).

see Intracerebral hemorrhage surgery indications.

Open craniotomy is the most widely studied surgical techniques in patients with supratentorial ICH. Other methods include endoscopic hemorrhage aspiration, use of fibrinolytic therapy to dissolve the clot followed by aspiration, and CT-guided stereotactic aspiration 4) 5).

see Intracerebral hemorrhage minimally invasive surgery

see Endoscopic surgery for intracerebral hemorrhage

Decompressive hemicraniectomy with hematoma evacuation for large ICH might be a safe and effective procedure in patients with severely disturbed consciousness and large hematoma volume 6).

Decompressive hemicraniectomy without clot evacuation appears feasible in patients with large ICH and deserves further investigation, preferably in a randomized controlled setting 7) 8)

Early decompressive hemicraniectomy (DH) with or without clot evacuation is feasible and safe for managing spontaneous ICH. The experience of Esquenazi et al. in a uncontrolled retrospective series, the largest such series in the modern era, suggests that it may be of particular benefit in patients with large non-dominant hemisphere ICH who are not moribund at presentation. These findings suggest that a prospective randomized trial of DH vs. craniotomy for ICH be conducted.

Over 7 years, DH was performed in 73 patients with clot evacuation in 86% and DH alone in 14%. The average ICH volume was 81 cc and the median DH surface area was 105 cm(2). 26 patients were comatose at initial presentation. Three-month functional outcomes were favorable in 29%, unfavorable in 44% and 27% of patients expired. Admission Glasgow Coma Scale (p=0.003), dominant hemisphere ICH location (p=0.01) and hematoma volume (p=0.002) contributed significantly to the outcome, as estimated by a multivariate analysis. Eight surgical complications occurred. 9).

Intracerebral hemorrhage surgery meta-analysis


Yi Y, Che W, Cao Y, Chen F, Liao J, Wang X, Lyu J. Prognostic data analysis of surgical treatments for intracerebral hemorrhage. Neurosurg Rev. 2022 Apr 19. doi: 10.1007/s10143-022-01785-5. Epub ahead of print. PMID: 35441246.

Aiyagari V. The clinical management of acute intracerebral hemorrhage. Expert Rev Neurother. 2015 Dec;15(12):1421-32. doi: 10.1586/14737175.2015.1113876. Epub 2015 Nov 13. PubMed PMID: 26565118.

Wang WM, Jiang C, Bai HM. New Insights in Minimally Invasive Surgery for Intracerebral Hemorrhage. Front Neurol Neurosci. 2015 Nov;37:155-65. doi: 10.1159/000437120. Epub 2015 Nov 12. PubMed PMID: 26588789.

Hersh EH, Gologorsky Y, Chartrain AG, Mocco J, Kellner CP. Minimally Invasive Surgery for Intracerebral Hemorrhage. Curr Neurol Neurosci Rep. 2018 May 9;18(6):34. doi: 10.1007/s11910-018-0836-4. Review. PubMed PMID: 29740726.

Hanley DF, Thompson RE, Muschelli J, Rosenblum M, McBee N, Lane K, Bistran-Hall AJ, Mayo SW, Keyl P, Gandhi D, Morgan TC, Ullman N, Mould WA, Carhuapoma JR, Kase C, Ziai W, Thompson CB, Yenokyan G, Huang E, Broaddus WC, Graham RS, Aldrich EF, Dodd R, Wijman C, Caron JL, Huang J, Camarata P, Mendelow AD, Gregson B, Janis S, Vespa P, Martin N, Awad I, Zuccarello M; MISTIE Investigators. Safety and efficacy of minimally invasive surgery plus alteplase in intracerebral haemorrhage evacuation (MISTIE): a randomised, controlled, open-label, phase 2 trial. Lancet Neurol. 2016 Nov;15(12):1228-1237. doi: 10.1016/S1474-4422(16)30234-4. Epub 2016 Oct 11. PubMed PMID: 27751554; PubMed Central PMCID: PMC5154627.

Takeuchi S, Wada K, Nagatani K, Otani N, Mori K. Decompressive hemicraniectomy for spontaneous intracerebral hemorrhage. Neurosurg Focus. 2013 May;34(5):E5. doi: 10.3171/2013.2.FOCUS12424. Review. PubMed PMID: 23634924.

Heuts SG, Bruce SS, Zacharia BE, Hickman ZL, Kellner CP, Sussman ES, McDowell MM, Bruce RA, Connolly ES Jr. Decompressive hemicraniectomy without clot evacuation in dominant-sided intracerebral hemorrhage with ICP crisis. Neurosurg Focus. 2013 May;34(5):E4. doi: 10.3171/2013.2.FOCUS1326. PubMed PMID: 23634923.

Bösel J, Zweckberger K, Hacke W. Haemorrhage and hemicraniectomy: refining surgery for stroke. Curr Opin Neurol. 2015 Feb;28(1):16-22. doi: 10.1097/WCO.0000000000000167. PubMed PMID: 25490194.

Esquenazi Y, Savitz SI, Khoury RE, McIntosh MA, Grotta JC, Tandon N. Decompressive hemicraniectomy with or without clot evacuation for large spontaneous supratentorial intracerebral hemorrhages. Clin Neurol Neurosurg. 2015 Jan;128:117-22. doi: 10.1016/j.clineuro.2014.11.015. Epub 2014 Nov 27. PubMed PMID: 25496934.

Peripheral nerve surgery training

Peripheral nerve surgery training

Neurosurgery residents exceeded the required minimum number of Peripheral nerve surgery and were increasingly more exposed to PNS. However, compared with their counterparts in orthopedic and plastic surgery, neurosurgery residents performed significantly fewer cases. Exposure for neurosurgery residents remains unchanged over the study period while plastic surgery residents experienced an increase in case volume. The deficiency in exposure for neurosurgical residents must be addressed to harness interest and proficiency in PNS 1).

In 2003, the goal of a study was to determine current practice patterns and attitudes of neurosurgeons toward peripheral nerve surgery.

A 13-question survey was mailed to all active members of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. Collected responses were entered into a database and were analyzed using statistical software.

Of 3800 surveys mailed there were 1728 responses for a 45% response rate. Analysis of the data revealed that respondents had a greater comfort level with simple peripheral nerve procedures, such as carpal tunnel release, and a lack of comfort with more complex peripheral nerve procedures, such as brachial plexus exploration. The majority of simple cases were treated by the surveyed neurosurgeons, whereas the majority of complex cases were referred to other surgeons, primarily to other neurosurgeons. The type of medical practice (academic, group, or solo) and the location of the practice (major city, small city, suburban setting, or rural area) showed a statistically significant correlation to simple case referral patterns, whereas the length of time since the respondent underwent training did not. Practice type and location, and years since training showed a statistically significant correlation to complex case referral patterns. Only 48.7% of the respondents believed that they had been given sufficient exposure to peripheral nerve surgery during residency training. The overwhelming majority (97.2%) of respondents favored keeping peripheral nerve surgery as part of the neurosurgical curriculum 2).

Peripheral nerve surgical competency.

Peripheral Nerve Surgery Fellowship (Mayo Clinic Rochester).

Salt Lake City

University of Calgary.

Copenhagen Peripheral Nerve Surgery Course 2022 https://peripheral-nerve-surgery.com/


Gohel P, White M, Agarwal N, Fields P D, Ozpinar A, Alan N. Longitudinal Analysis of Peripheral Nerve Surgery Training: Comparison of Neurosurgery to Plastic and Orthopedic Surgery. World Neurosurg. 2022 Jan 30:S1878-8750(22)00108-5. doi: 10.1016/j.wneu.2022.01.094. Epub ahead of print. PMID: 35108647.

Maniker A, Passannante M. Peripheral nerve surgery and neurosurgeons: results of a national survey of practice patterns and attitudes. J Neurosurg. 2003 Jun;98(6):1159-64. doi: 10.3171/jns.2003.98.6.1159. PMID: 12816257.

Intracerebral hemorrhage minimally invasive surgery

Intracerebral hemorrhage minimally invasive surgery

Surgical treatment for hematoma evacuation has not yet shown a clear benefit over medical management despite promising preclinical studies. Minimally invasive treatment options for hematoma evacuation are under investigation but remain in early-stage clinical trials. Robotics has the potential to improve treatment 1)

Cavallo et al systematically reviewed the role of MIS in the acute management of ICH using various techniques.

A comprehensive electronic search for relevant articles was conducted on several relevant international databases, including PUBMED (Medline), EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL).

The primary literature research resulted in 1134 articles. In total, 116 publications finally met the eligibility criteria to be included in this systematic review. Five major MIS categories for the evacuation of ICH were identified, respectively: minimally invasive direct aspiration with or without thrombolytics, endoscope assisted technique, sonothrombolysis, aspiration-irrigation device and endoport-assisted evacuation.

The role of minimally invasive techniques in the management of ICH remains under dispute. However, a mounting evidence in the literature demonstrates that MIS is associated with significantly improved outcomes when compared with conservative treatment and conventional surgical evacuation strategy 2).

In December of 2016, phase 2 of the Minimally Invasive Surgery Plus Rt-PA for ICH Evacuation (MISTIE) study demonstrated that this form of stereotactic thrombolysis safely reduces clot burden and may improve functional outcome 6 months after injury. A smaller arm of this study, the Intraoperative Stereotactic Computer Tomography-Guided Endoscopic Surgery (ICES) study, also demonstrated feasibility and good functional outcome for endoscopic minimally invasive evacuation. Early-phase clinical studies evaluating various forms of minimally invasive surgery for intracerebral hemorrhage evacuation have shown safety and feasibility with a preliminary signal towards improved functional long-term outcome. Results from phase 3 studies addressing various minimally invasive techniques are imminent and will shape how intracerebral hemorrhage is treated 3).

Meta-analyses of surgery for ICH have also indicated that minimal interventional techniques using topical thrombolysis or endoscopy via burrholes or even twist drill aspiration may be particularly successful for the treatment of supratentorial ICH, especially when the clot is deep seated. Ongoing CLEAR III Clinical Trial and MISTIE III Clinical Trial should confirm this in the fullness of time 4).

Some minimally invasive treatments have been applied to hematoma evacuation and could improve prognosis to some extent. Up to now, studies on minimally invasive surgery for patients with spontaneous intracerebral hemorrhage are still insufficient.

The MISTICH is a multi-center, prospective, randomized, assessor-blinded, parallel group, controlled clinical trial. 2448 eligible patients will be assigned to neuroendoscopy group, stereotactic aspiration group and craniotomy group randomly. Patients will receive the corresponding surgery based on the result of randomization. Surgeries will be performed by well-trained surgeons and standard medical treatment will be given to all patients. Patients will be followed up at 7 days, 30 days, and 6 months. The primary outcome of this study is unfavorable outcome at 6 months. Secondary outcomes include: mortality at 30 days and 6 months after surgery; neurological functional status of 6 months after surgery; complications including rebleeding, ischemic stroke and intracranial infection; days of hospitalization.

The MISTICH trial is a randomized controlled trial designed to determine whether minimally invasive surgeries could improve the prognosis for patients with spontaneous intracerebral hemorrhage compared with craniotomy 5).

Endoscopic surgery for intracerebral hemorrhage

see Endoscopic surgery for intracerebral hemorrhage.

The MIS score is a simple grading scale that can be utilized to select patients who are suited for minimal invasive drainage surgery. When MIS score is 0-1, minimal invasive surgery is strongly recommended for patients with spontaneous cerebral hemorrhage. The scale merits further prospective studies to fully determine its efficacy 6).

Minimally invasive technologies, such as endoport systems, may offer a better risk to benefit profile for ICH evacuation than conventional approaches.

see BrainPath endoport system

Endoscopic surgery is increasingly used to evacuate ICHs; however, the narrow rigid sheath may be limiting. Hwang et al report the usefulness of a soft plastic membrane sheath for endoscopic evacuation of ICHs.

The 20 × 100-mm flat membrane sheath was made of polyester film. Before introducing the sheath into the ICH cavity under navigation, one side was tucked into the opposite side to make a narrow four-layered tube. After inserting it in the brain, the tucked-in leaf was pulled out, and the slit-like tube was ready to remove the hematoma. A rigid endoscope and various instruments were introduced into the sheath. Large ICHs in the putamen and thalamus were evacuated under endoscopic visualization using the same microsurgical instruments.

This technique was applied to 41 patients. Nearly complete evacuation of all hematomas was achieved. No surgical complication or rebleeding occurred. The new membrane sheath allowed more room for accommodating and handling the instruments, including bipolar forceps.

This flat membrane sheath is disposable and easy to prepare, which could overcome the limitation of the instruments to allow for efficient evacuation of an ICH using the same microsurgical techniques 7).


Musa MJ, Carpenter AB, Kellner C, Sigounas D, Godage I, Sengupta S, Oluigbo C, Cleary K, Chen Y. Minimally Invasive Intracerebral Hemorrhage Evacuation: A review. Ann Biomed Eng. 2022 Feb 28. doi: 10.1007/s10439-022-02934-z. Epub ahead of print. PMID: 35226279.

Cavallo C, Zhao X, Abou Al-Shaar H, Weiss M, Gandhi S, Belykh E, Tayebi-Meybodi A, Labib M, Preul MC, Nakaji P. Minimally invasive approaches for the evacuation of intracerebral hemorrhage: a systematic review. J Neurosurg Sci. 2018 Aug 28. doi: 10.23736/S0390-5616.18.04557-5. [Epub ahead of print] PubMed PMID: 30160081.

Hersh EH, Gologorsky Y, Chartrain AG, Mocco J, Kellner CP. Minimally Invasive Surgery for Intracerebral Hemorrhage. Curr Neurol Neurosci Rep. 2018 May 9;18(6):34. doi: 10.1007/s11910-018-0836-4. Review. PubMed PMID: 29740726.

Mendelow AD. Surgical Craniotomy for Intracerebral Haemorrhage. Front Neurol Neurosci. 2015 Nov;37:148-54. doi: 10.1159/000437119. Epub 2015 Nov 12. PubMed PMID: 26588582.

Zheng J, Li H, Guo R, Lin S, Hu X, Dong W, Ma L, Fang Y, Xiao A, Liu M, You C. Minimally invasive surgery treatment for the patients with spontaneous supratentorial intracerebral hemorrhage (MISTICH): protocol of a multi-center randomized controlled trial. BMC Neurol. 2014 Oct 10;14(1):206. doi: 10.1186/s12883-014-0206-z. PubMed PMID: 25300611; PubMed Central PMCID: PMC4194378.

Hu Y, Cao J, Hou X, Liu G. MIS Score: Prediction Model for Minimally Invasive Surgery. World Neurosurg. 2016 Dec 31. pii: S1878-8750(16)31417-6. doi: 10.1016/j.wneu.2016.12.102. [Epub ahead of print] PubMed PMID: 28049035.

Hwang SC, Yeo DG, Shin DS, Kim BT. Soft membrane sheath for endoscopic surgery of intracerebral hematomas. World Neurosurg. 2016 Mar 9. pii: S1878-8750(16)00405-8. doi: 10.1016/j.wneu.2016.03.001. [Epub ahead of print] PubMed PMID: 26970478.

Fluorescein sodium guided resection of high-grade glioma

Fluorescein sodium guided resection of high-grade glioma

Naik et al. compared 5 aminolevulinic acid fluorescence guided resection of high-grade gliomaFluorescein sodium guided resection of high-grade glioma. (FS), and Intraoperative magnetic resonance imaging-guided resection of high-grade glioma (IMRI) with no image guidance to determine the best intraoperative navigation method to maximize rates of gross total resection (GTR) and outcomes. A frequentist network meta-analysis was performed following standard PRISMA guidelines (PROSPERO registration CRD42021268659). Surface-under-the-cumulative ranking (SUCRA) analysis was executed to hierarchically rank modalities by the outcome of interestHeterogeneity was measured by the I2 statisticPublication bias was assessed by funnel plots and the use of Egger’s test. Statistical significance was determined by p < 0.05. Twenty-three studies were included for analysis with a total of 2,643 patients. Network meta-analysis comparing 5-ALA, IMRI, and FS was performed. The primary outcome assessed was the rate of GTR. Analysis revealed the superiority of all intraoperative navigation to control (no navigation). SUCRA analysis revealed the superiority of IMRI + 5-ALA, IMRI alone, followed by FS, and 5-ALA. Overall survival (OS) and progression-free survival (PFS) were also examined. FS (vs. control) was associated with improved OS, while IMRI was associated with improved PFS (vs. control, FS, and 5-ALA). Intraoperative navigation using IMRI, FS, and 5-ALA lead to greater rates of GTR in HGGs. FS and 5-ALA also yielded improvement in OS and PFS. Further studies are needed to evaluate differences in survival benefit, operative duration, and cost 1).

Fluorescein can be used as a viable alternative to 5-ALA for intraoperative fluorescent guidance in brain tumor surgery. Comparative, prospective, and randomized studies are much needed 2).

5-ALA fluorescence-guided surgery has shortcomings such as drug’s phototoxicity, extortionate price, and not being approved by Food and Drug Administration, which limited its widespread application.

Due to the above limitations, sodium fluorescein guided surgery had been paid more attention by neurosurgeons than 5-ALA. FL is an easily available and biosafe fluorescein dye with a peak excitation at 465 to 490 nm and emission between 500 and 550 nm and has been used extensively and safely for many years especially in ophthalmology 3) 4).

5 aminolevulinic acid is still the preferred and more established fluorescent dye used during high-grade gliomas resection, with Fluorescein sodium gaining-attention, really cheaper and more ductile alternative 5).

The use of fluorescein fluorescence-guided stereotactic needle biopsy has been shown to improve diagnostic accuracy and to expedite operative procedure in the stereotactic needle biopsy of high-grade gliomas.

see Fluoropen.

The first use of fluorescence for brain tumour surgery was in 1948 by G.E. Moore 6) using fluorescein sodium, a strongly fluorescing and non-toxic (apart from rare anaphylaxis 7) compound). In malignant brain tumours with their inherent blood-brain barrier breakdown, fluorescein is extravasated and might serve to mark tumours.

Today, fluorescein sodium is again under scrutiny 8) 9). using a novel filter system by Zeiss (YELLOW 560) for the microscope. This filter visualises fluorescein and allows good background discrimination. Furthermore, fluorescein can be injected any time and is low in cost. Nevertheless, its use in brain tumour surgery is off-label and thus restricted to clinical studies. Little is known about the best timing of i.v. fluorescein application before resection. Injecting fluorescein too early might result in unspecific propagation with oedema, whereas acute injections might be useful for detecting abnormally perfused tumour tissue. Levels in the blood will be high, especially with acute injections, leading to fluorescence of all perfused brain tissue. Such time-resolved in- formation on the specificity of fluorescein are not available.

Overall, Schwake et al observed no clear value of fluorescein in a small study, which they closed prematurely. Clearly, further work elucidating optimal timing and dosing of fluorescein is warranted. 10)

Sodium fluorescein (SF) was first used for the identification of different types of brain tumors in 1948 11).

Since then, the use of SF and others fluorescent tracers have been described in literature particularly that dealing with glioblastoma multiforme resection 12) 13) 14)

Metastatic lesion were also enhanced by SF 15)16).

Also in skull base tumors 17).

“Fluorescein sodium”, the sodium salt of fluorescein, is used extensively as a diagnostic tool in the field of ophthalmology and optometry, where topical fluorescein is used in the diagnosis of corneal abrasions, corneal ulcers and herpetic corneal infections. It is also used in rigid gas permeable contact lens fitting to evaluate the tear layer under the lens. It is available as sterile single-use sachets containing lint-free paper applicators soaked in fluorescein sodium.

Intravenous or oral fluorescein is used in fluorescein angiography in research and to diagnose and categorize vascular disorders including retinal disease macular degeneration, diabetic retinopathy, inflammatory intraocular conditions, and intraocular tumors. It is also being used increasingly during surgery for brain tumors.

Diluted fluorescein dye has been used to localise multiple muscular ventricular septal defects during open heart surgery and confirm the presence of any residual defects.

Intravenous fluorescein sodium has been used during resection of high-grade gliomas to help the surgeon visualize tumor margins. Several studies have reported improved rates of gross total resection (GTR) using high doses of fluorescein sodium under white light. The introduction of a fluorescein-specific camera that allows for high-quality intraoperative imaging and use of very low dose fluorescein has drawn new attention to this fluorophore.

Fluorescein sodium does not appear to selectively accumulate in astrocytoma cells but in extracellular tumor cell rich locations, suggesting that fluorescein is a marker for areas of compromised blood brain barrier within high grade astrocytoma. Fluorescein fluorescence appears to correlate intraoperatively with the areas of MR enhancement, thus representing a practical tool to help the surgeon achieve GTR of the enhancing tumor regions 18).

Magnetic resonance diffusion tensor imaging (MR-DTI) and fluorescein sodium dyeing guiding for surgery of glioma located in brain motor functional areas can increase the gross total resection rate, decrease the paralysis rate caused by surgery, and improve patient quality of life compared with traditional glioma surgery 19).

Intrathecal fluorescein (ITF) is extremely specific and very sensitive for detecting intraoperative CSF leaks. Although false negatives can occur, these patients do not appear to be at risk for postoperative CSF leak. The use of ITF may help surgeons prevent postoperative CSF leaks by intraoperatively detecting and confirming a watertight repair 20).


Naik A, Smith EJ, Barreau A, Nyaeme M, Cramer SW, Najafali D, Krist DT, Arnold PM, Hassaneen W. Comparison of fluorescein sodium, 5-ALA, and intraoperative MRI for resection of high-grade gliomas: A systematic review and network meta-analysis. J Clin Neurosci. 2022 Feb 22;98:240-247. doi: 10.1016/j.jocn.2022.02.028. Epub ahead of print. PMID: 35219089.

Hansen RW, Pedersen CB, Halle B, Korshoej AR, Schulz MK, Kristensen BW, Poulsen FR. Comparison of 5-aminolevulinic acid and sodium fluorescein for intraoperative tumor visualization in patients with high-grade gliomas: a single-center retrospective study. J Neurosurg. 2019 Oct 4:1-8. doi: 10.3171/2019.6.JNS191531. [Epub ahead of print] PubMed PMID: 31585425.

Novotny H. R., Alvis D. L. A method of photographing fluorescence in circulating blood in the human retina. Circulation. 1961;24:82–86. doi: 10.1161/01.cir.24.1.82.

Kwan A. S. L., Barry C., McAllister I. L., Constable I. Fluorescein angiography and adverse drug reactions revisited: the Lions Eye experience. Clinical and Experimental Ophthalmology. 2006;34(1):33–38. doi: 10.1111/j.1442-9071.2006.01136.x.

Acerbi F, Restelli F, De Laurentis C, Falco J, Cavallo C, Broggi M, Höhne J, Schebesch KM, Schiariti M, Ferroli P. Fluorescent tracers in neurosurgical procedures: an European survey. J Neurosurg Sci. 2018 Jul 17. doi: 10.23736/S0390-5616.18.04494-6. [Epub ahead of print] PubMed PMID: 30014688.

Moore GE, Peyton WT, French LA, Walker WW (1948) The clinical use of fluorescein in neurosurgery; the localization of brain tumors. J Neurosurg 5:392–398

Dilek O, Ihsan A, Tulay H (2011) Anaphylactic reaction after fluo- rescein sodium administration during intracranial surgery. J Clin Neurosci 18:430–431

Acerbi F, Broggi M, Eoli M, Anghileri E, Cuppini L, Pollo B, Schiariti M, Visintini S, Ori C, Franzini A, Broggi G, Ferroli P (2013) Fluorescein-guided surgery for grade IV gli- omas with a dedicated filter on the surgical microscope: pre- liminary results in 12 cases. Acta Neurochir (Wien) 155: 1277–1286

Schebesch KM, Proescholdt M, Höhne J, Hohenberger C, Hansen E, Reimenschneider MJ, Ullrich W, Doenitz C, Schlair J, Lange M, Brawanski A (2013) Sodium fluorescein-guided resection under the YELLOW 560 nm surgical microscope filter in malignant brain tumor surgery—a feasibility study. Acta Neurochir (Wien) 155:693–699

Schwake M, Stummer W, Suero Molina EJ, Wölfer J. Simultaneous fluorescein sodium and 5-ALA in fluorescence-guided glioma surgery. Acta Neurochir (Wien). 2015 May;157(5):877-9. doi: 10.1007/s00701-015-2401-0. Epub 2015 Mar 28. PubMed PMID: 25820632.
11) , 15)

Moore GE, Peyton WT, French LA, Walker WW. The clinical use of fluorescein in neurosurgery. J Neurosurg. 1948;5:392–8.

Chae MP, Song SW, Park SH, Park CK. Experience with 5- aminolevulinic Acid in fluorescence-guided resection of a deep sylvian meningioma. J Korean Neurosurg Soc. 2012;52:558–60.

Kuroiwa T, Kajimoto Y, Ohta T. Development of a fluorescein operative microscope for use during malignant glioma surgery: A technical note and preliminary report. Surg Neurol. 1998;50:41–9.

Kuroiwa T, Kajimoto Y, Ohta T. Comparison between operative findings on malignant glioma by a fluorescein surgical microscopy and histological findings. Neurol Res. 1999;21:130–4.

Okuda T, Kataoka K, Taneda M. Metastatic brain tumor surgery using fluorescein sodium: Technical note. Minim Invasive Neurosurg. 2007;50:382–4.

da Silva CE, da Silva JL, da Silva VD. Use of sodium fluorescein in skull base tumors. Surg Neurol Int. 2010;1:70.

Diaz RJ, Dios RR, Hattab EM, Burrell K, Rakopoulos P, Sabha N, Hawkins C, Zadeh G, Rutka JT, Cohen-Gadol AA. Study of the biodistribution of fluorescein in glioma-infiltrated mouse brain and histopathological correlation of intraoperative findings in high-grade gliomas resected under fluorescein fluorescence guidance. J Neurosurg. 2015 Jun;122(6):1360-9. doi: 10.3171/2015.2.JNS132507. Epub 2015 Apr 3. PubMed PMID: 25839919.

Liu JG, Yang SF, Liu YH, Wang X, Mao Q. Magnetic resonance diffusion tensor imaging with fluorescein sodium dyeing for surgery of gliomas in brain motor functional areas. Chin Med J (Engl). 2013 Jul;126(13):2418-23. PubMed PMID: 23823811.

Raza SM, Banu MA, Donaldson A, Patel KS, Anand VK, Schwartz TH. Sensitivity and specificity of intrathecal fluorescein and white light excitation for detecting intraoperative cerebrospinal fluid leak in endoscopic skull base surgery: a prospective study. J Neurosurg. 2016 Mar;124(3):621-6. doi: 10.3171/2014.12.JNS14995. Epub 2015 Aug 21. PubMed PMID: 26295912.

Anosmia after anterior communicating artery aneurysm surgery

Anosmia after anterior communicating artery aneurysm surgery

For Bor et al. anosmia occurs after coiling in 1 of every 6 SAH patients, but has a good prognosis in most patients. The cause of anosmia after coiling for ruptured aneurysms remains elusive; severity of the initial hemorrhage or long lasting hydrocephalus may be contributing factors 1).

In patients with subarachnoid hemorrhage (SAH), anosmia has mainly been reported after surgery for anterior communicating artery aneurysms. Olfactory dysfunction after SAH caused by rupture of the ACoA are very frequent and were present in both treatment groups (aneurysmal clip placement and coil embolization).

Cerebral vasospasm and frontal lobe lesions are related to worse performance on an olfactory test in patients undergoing endovascular coil embolization 2).

Both clip treatment and SAH contribute to the occurrence of anosmia, with different chances of improvement. Olfactory dysfunction occurs in almost all patients on the side of surgery and can occur subclinically after coil deployment 3).

Its occurrence after coiling suggests not only damage to the olfactory nerve by clipping but also that the SAH itself plays a role in its pathogenesis 4).

The highest incidence of olfactory dysfunction following a pterional approach and its modifications for an intracranial aneurysm has been reported in cases of anterior communicating artery (ACoA) aneurysms. The radiological characteristics of unruptured ACoA aneurysms affecting the extent of retraction of the frontal lobe and olfactory nerve were investigated as risk factors for postoperative olfactory dysfunction. In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction. 5).

Wongsuriyanan and Sriamornrattanakul published that the interhemispheric approach provided an excellent surgical corridor for clipping anterior communicating artery aneurysms (AcoAAs). However, an important disadvantage of the approach is obtaining proximal control at A1 in the last stage of dissection, especially in anterior or superior projecting AcoAAs and ruptured cases.

Postoperative anosmia was detected in 22.7% 6).

For Ito et al. the causes of postoperative anosmia in subfrontal and interhemispheric approach were as follows: sectioning of olfactory tracts intentionally or not, avulsion of olfactory bulbs and probability of ischemic or minor mechanical insults to olfactory tracts. However, these matters rarely occur in posterior interhemispheric approach because of little exposure of olfactory nerves. The mechanisms of postoperative anosmia in posterior interhemispheric approach were considered to be as follows: sinking of frontal lobes due to excessive drainage of cerebrospinal fluid and over-retraction of frontal lobes. The incidence of postoperative anosmia decreased from 27.0% via subfrontal and interhemispheric approach to 5.5% via posterior interhemispheric approach 7).

Superior direction of aneurysm appears associated with postoperative olfactory dysfunction. Olfactory protection using gelfoam and fibrin glue could be a simple, safe, and useful method to preserve olfactory function during A-com aneurysm surgery. 8).

For Aydin et al. the functions of olfactory nerve could be preserved at a relatively high rate of 85 per cent. This high rate resulted from the microtechnique employed as well as the relatively cautious frontal lobe retraction which was less than 1.5 cm 9).

For Fujiwara et al. Unilateral dural incision and unilateral brain retraction without elevation of the frontal lobe from the frontal base are important, because frontal lobe depression and elevation during surgery may injure the olfactory nerve 10).

Olfactory dysfunction has an important impact on quality of life. Recovery after traumatic anosmia has been recorded up to 5 years after injury. Nevertheless, the authors believe that the damage is permanent when lasting 35 months or longer 11).

The interhemispheric approach (IHA) provides an excellent surgical corridor for clipping anterior communicating artery aneurysms (AcoAAs). However, an important disadvantage of the approach is obtaining proximal control at A1 in the last stage of dissection, especially in anterior or superior projecting AcoAAs and ruptured cases. Wongsuriyanan and Sriamornrattanakul described and evaluated the microsurgical clipping of AcoAAs using the IHA with early A1 exposure.

This was a retrospective descriptive study in patients with AcoAA who received microsurgical clipping through the IHA with early A1 exposure between April 2016 and May 2019. Aneurysm morphology, projection, completeness of clipping, surgical complications, and outcomes were collected from medical records.

Twenty-five patients with AcoAA received microsurgical clipping via the IHA with early A1 exposure. Twenty-three patients (92%) presented with subarachnoid hemorrhage. Intraoperative rupture while dissecting the interhemispheric fissure occurred in 2 cases, for which proximal control via subfrontal route was effectively performed. Of the patients, 100% achieved complete obliteration of their aneurysms. Postoperative anosmia was detected in 22.7%. In ruptured cases, 16 (88.9%) of the good grade patients achieved a good outcome (Glasgow Outcome Scale scores of 4 and 5) at 3 months after the operation.

The IHA with early A1 is safe and effective for clipping AcoAAs. 12).

Hendrix et al. assessed the risk for olfactory dysfunction following surgical treatment of unruptured cerebral aneurysm via the supraorbital minicraniotomy. A retrospective review of patients with electively treated cerebral aneurysms who underwent perioperative assessment of olfactory function using a sniffin’ sticks odor identification test between January 2015 and January 2016 was performed. A subgroup of patients without history of subarachnoid hemorrhage, without prior intracranial aneurysm treatment, and confirmed olfactory function underwent supraorbital keyhole craniotomy for aneurysm clipping. Microscopic and endoscopic videos were reviewed for this subgroup. Sixty-four patients who underwent elective aneurysm treatment either via surgical clipping or endovascular aneurysm obliteration were identified. Prior to treatment, 4/64 (6.3%) demonstrated bilateral anosmia. Collectively, 14 patients (21.9%) met subgroup criteria of supraorbital keyhole craniotomy for aneurysm clipping. Here, olfactory performance significantly decreased postoperatively on the side of craniotomy (ipsilateral, P = 0.007), whereas contralateral and bilateral olfactory function remained unaltered (P = 0.301 and P = 0.582, respectively). Consequently, 4/14 patients (28.6%) demonstrated ipsilateral anosmia 3 months after surgery. One patient (1/14, 7.1%) also experienced contralateral anosmia resulting in bilateral anosmia. Intraoperative visualization of the olfactory tract and surgical maneuvers do not facilitate prediction of olfactory outcome. The supraorbital keyhole craniotomy harbors a specific risk for unilateral olfactory deterioration. Lack of perioperative olfactory assessment likely results in underestimation of the risk for olfactory decline. Despite uneventful surgery, prediction of postoperative olfactory function and dysfunction remain challenging 13).

A total of 63 patients (aged 41-79 yr, mean 64 yr) with relatively small AcomA aneurysms clipped via the lateral supraorbital approach were retrospectively analyzed among the 105 AcomA aneurysms treated by clipping from 2005 to 2014. Neurological and cognitive functions were examined by several scales, including the modified Rankin Scale (mRS) and Mini-Mental Status Examination. The depressive state was assessed using the Beck Depression Inventory and Hamilton Depression Scale. The state of clipping was assessed 1 yr and then every few years after the operation by 3-dimensional computed tomography angiography.

Complete aneurysm neck clipping was confirmed in 62 aneurysms (98.4%). Perioperative complications occurred in 5 patients (5/63; mild frontalis muscle weakness in 3, anosmia in 1, and meningitis in 1). The mean clinical follow-up period was 5.2 ± 2.1 yr. No patient showed an mRS score more than 2 and all were completely independent in daily life. The depression scores were significantly improved after surgery. The overall mortality was 0% and overall morbidity (mRS score > 2 or Mini-Mental Status Examination score < 24) was 1.6%. All completely clipped aneurysms did not show any recurrence during the mean follow-up period of 4.9 ± 2.1 yr.

Keyhole Lateral supraorbital approach to clip relatively small unruptured AcomA aneurysm promises less invasive and durable treatment 14).

Cho et al. retrospectively reviewed the medical records of patients who underwent surgical clipping for unruptured aneurysm from 2011-2013 by the same senior attending physician. Since March 2012, olfactory protection using gelfoam and fibrin glue was applied in A-com aneurysm surgery. Therefore we categorized patients in two groups from this time-protected group and unprotected group.

Of the 63 enrolled patients, 16 patients showed postoperative olfactory dysfunction-including 8 anosmia patients (protected group : unprotected group=1 : 7) and 8 hyposmia patients (protected group : unprotected group=2 : 6). Thirty five patients who received olfactory protection during surgery showed a lower rate of anosmia (p=0.037, OR 10.516, 95% CI 1.159-95.449) and olfactory dysfunction (p=0.003, OR 8.693, 95% CI 2.138-35.356). Superior direction of the aneurysm was also associated with a risk of olfactory dysfunction (p=0.015, OR 5.535, 95% CI 1.390-22.039).

Superior direction of aneurysm appears associated with postoperative olfactory dysfunction. Olfactory protection using gelfoam and fibrin glue could be a simple, safe, and useful method to preserve olfactory function during A-com aneurysm surgery. 15).

The highest incidence of olfactory dysfunction following a pterional approach and its modifications for an intracranial aneurysm has been reported in cases of anterior communicating artery (ACoA) aneurysms. The radiological characteristics of unruptured ACoA aneurysms affecting the extent of retraction of the frontal lobe and olfactory nerve were investigated as risk factors for postoperative olfactory dysfunction.

Methods: A total of 102 patients who underwent a pterional or superciliary keyhole approach to clip an unruptured ACoA aneurysm from 2006 to 2013 were included in this study. Those patients who complained of permanent olfactory dysfunction after their aneurysm surgery, during a postoperative office visit or a telephone interview, were invited to undergo an olfactory test, the Korean version of the Sniffin’ Sticks test. In addition, the angiographic characteristics of ACoA aneurysms, including the maximum diameter, the projecting direction of the aneurysm, and the height of the neck of the aneurysm, were all recorded based on digital subtraction angiography and sagittal brain images reconstructed using CT angiography. Furthermore, the extent of the brain retraction was estimated based on the height of the ACoA aneurysm neck.

Results: Eleven patients (10.8%) exhibited objective olfactory dysfunction in the Sniffin’ Sticks test, among whom 9 were anosmic and 2 were hyposmic. Univariate and multivariate analyses revealed that the direction of the ACoA aneurysm, ACoA aneurysm neck height, and estimated extent of brain retraction were statistically significant risk factors for postoperative olfactory dysfunction. Based on a receiver operating characteristic (ROC) analysis, an ACoA aneurysm neck height > 9 mm and estimated brain retraction > 12 mm were chosen as the optimal cutoff values for differentiating anosmic/hyposmic from normosmic patients. The values for the area under the ROC curves were 0.939 and 0.961, respectively.

Conclusions: In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction. 16).

Matano et al. presented a fibrin-gelatin fixation method that provides reinforcement and moisture to help preserve the olfactory nerve when using the anterior interhemispheric approach and describe the results and outcomes of this technique. We analyze the outcomes with this technique in 45 patients who undergo surgery for aneurysms, brain tumors, or other pathologies via the anterior interhemispheric approach. Anosmia occurred in 4 patients (8.8%); it was transient in 2 (4.4%) and permanent in the remaining 2 (4.4%). Brain tumors clearly attached to the olfactory nerve were resected in the patients with permanent anosmia. We found a significant difference in the presence of anosmia between patients with or without lesions that were attaching the olfactory nerve (p = 0.011). Our results suggested that fibrin-gelatin fixation method can reduce the reported risk of anosmia. However, the possibility of olfactory nerve damage is relatively high when operating on brain tumors attaching olfactory nerve 17).

Lai et al. presented the operative experiences in a consecutive series of 103 patients with 115 unruptured AcomA aneurysms. Clinical results, operative complications, angiographic outcomes and prognostic factors associated with surgery are presented. Of the 115 aneurysm repairs attempted, 114 were treated by clipping or excision and suture. One aneurysm, less than 2mm, was wrapped. Six patients (5.8%; 95% confidence interval [CI], 2.5-12.4) experienced a new permanent neurological deficit. There was no postoperative mortality. Transient morbidity occurred in 11 patients (10.7%; 95% CI, 5.9-18.3), including transient anosmia (four patients), acute postoperative confusion and memory disturbances (four patients), extradural haematoma requiring surgery (two patients) and cerebrospinal fluid rhinorrhea (one patient). Of the 84 aneurysms (73.0%) that had documented postoperative angiography, 82 (97.6%) had complete obliteration of the aneurysm and two (2.4%) had neck remnants (mean angiographic follow-up 28.0 months; range, 1.6-146.4 months). Retreatment was performed in one patient (1.0%). Logistic regression analysis of risk factors revealed that aneurysm size (p<0.01) was a significant predictor of outcome. There was no incidence of subarachnoid haemorrhage in the 272 person years of follow-up. In the current study, surgical treatment of unruptured AcomA aneurysms resulted in 5.8% morbidity and no mortality. The robustness of aneurysm repair achieved by open microsurgery is an important consideration when considering the option between endovascular and microsurgical treatment for unruptured AcomA aneurysms. 18).

Nakayama et al. studied the incidence of postoperative infection related to CSF leakage and anosmia in basal interhemispheric approach (BIH). Between April, 1990 to March, 2009, 142 cases of anterior communicating (Acom) aneurysm including both unruptured and ruptured have been treated by clipping surgery using BIH. We retrospectively obtained clinical informations from medical records and video records about infectious complications, CSF leakage of cerebrospinal fluid (CSF), olfactory dysfunction and intraoperative findings of damage to the olfactory nerve. In most cases (139 patients, 97%), frontal sinus were opened at craniotomy. Of all, CSF rinorrhea occurred in 4 cases (2.8%), and meningitis in 6 cases. There was only one patient who sufferd from meningitis due to CSF rinorrhea. All that patients recovered completely without deficit. Anosmia occurred in 6 cases (4.2%), and intraoperative injuries in 4 cases (2.8%). There was only one patient in whom anosmia was consistent with nerve injury. In conclusion, BIH is an appropriate procedure for infection risk control in Acom aneurysm surgery. It is difficult to avoid olfactory dysfunction completely, even if olfactory nerves are preserved in form. 19).

The horizontal head position was adopted in the unilateral anterior interhemispheric approach to treat an anterior communicating artery (ACoA) aneurysm. The patient was placed in the supine position. The patient’s head was rotated to the right to orient the midline horizontally, and tilted 45 degrees superiorly. After bicoronal skin incision and bifrontal craniotomy, the dura on the right side (downside) was opened. Dissection of the right interhemispheric fissure allowed gravity to retract the right (downside) hemisphere, which fell away from the falx, while the falx supported the upside hemisphere. The present approach was used in three patients with ACoA aneurysm between January 2009 and April 2010. The aneurysms were adequately clipped with this approach. No complication related to the approach occurred. No patients exhibited anosmia after surgery. This approach is useful for ACoA aneurysms. 20).

Beseoglu et al. in 2003 introduced a minimally invasive transorbital keyhole approach. Because this approach requires removal of the orbital rim and orbital roof, there have been concerns regarding perioperative morbidity, long-term morbidity, and cosmetic results. The authors evaluated approach-related morbidity and cosmetic results in their patients to determine the rate of complications and compared this to published reports of similar approaches.

Material: Seventy-one patients (41 female, 30 male) underwent operations using this approach between 2004 and 2008. Immediate approach-related morbidity was recorded after the operation. Late morbidity was determined after 7 months by an independent examiner while cosmetic results were self-rated by the patient using a questionnaire.

Results: Fifty-one (72%) of 71 patients had no postoperative complications and 12 (16.9%) had minor complications, the most common of which was subgaleal CSF collection (7.0%). Other minor complications included facial nerve palsy (2.8%), hyposphagma (2.8%), periorbital swelling due to periorbital hematoma (2.8%), and subdural hematoma (1.4%). Major complications requiring surgical revision occurred in 4 patients (5.6%); these were CSF fistulas in 2 patients, pneumocephalus in 1 patient, and a hematoma in 1 patient. Forty-nine (90.7%) of all 54 examined patients rated the cosmetic results as very good or good. Major long-term morbidity was hyposmia or anosmia (14 patients) followed by hypoesthesia around the scar (9 patients).

The transorbital keyhole approach is a feasible approach with a low-risk profile for postoperative or long-term morbidity and excellent cosmetic outcome 21)

Although the frequency of smell disorders after the operations of the anterior communicating artery aneurysm depends to a large degree on the used surgical approach, several independent of surgery factors may contribute to the postoperative smell tests outcome. THE AIM OF OUR STUDIES: The evaluation of the sense of smell in patients who underwent the operation of ruptured anterior communicating artery aneurysm using pterional approach.

Material and methods: In the retrospective studies the results of smell test of the group of 21 patients operated for ruptured anterior communicating artery aneurysm and 21 healthy volunteers of control group were compared. The patients suffering from neurodegenerative, metabolic and endocrynological disorders, as well as those with rhinoscopic symptoms of rhinosinusitis and with decreased nasal potency confirmed by anterior rhinomanometry were excluded from the study.

Results: During the operations it was possible to anatomically retain olfactory nerves in all operated patients. Severe smell disorders (severe hyposmia and anosmia) were detected in 1 (4.7%) patient of the control group and in 6 (28.5%) patients of postoperative group. The mean composite olfactory score in Cain test of the postoperative group was 4.53, and in the control group 5.47 points. The difference did not reach statistic significance (Mann-Whitney test, p = 0.068).

Conclusions: Although pterional approach to anterior communicating artery is relatively low traumatic to olfactory tract, the subarachnoid hemorrhage may have an unfavorable effect on postoperative olfactory nerve functioning. Considering the fact, that in spite of thorough examination of the patients, we were not able to exclude from the studied groups all the patients with preoperatively impaired smell, it seems reasonable to perform similar smell test studies in the prospective way 22).

Bor et al. interviewed all patients who resumed independent living after SAH treated with coiling between 1997 and 2007. We assessed by means of logistic regression analyses whether risk of anosmia was influenced by site of the ruptured aneurysm, neurological condition on admission, amount of extravasated blood, hydrocephalus, and treatment for hydrocephalus.

Of 197 patients, 35 (18%; 95%CI:12 to 23) experienced anosmia. Anosmia had improved in 23 (66%) of them; in 20 the recovery had been complete after a median period of 6 weeks (SD +/-6.5). Intraventricular hemorrhage was a risk factor for anosmia (OR 2.4; 95%CI:1.0 to 5.9). Anterior aneurysm location (OR 1.1; 95%CI:0.5 to 2.3) and high amount of extravasated blood (OR 0.9; 95%CI:0.4 to 2.1) were not related to anosmia.

Anosmia occurs after coiling in 1 of every 6 SAH patients, but has a good prognosis in most patients. The cause of anosmia after coiling for ruptured aneurysms remains elusive; severity of the initial hemorrhage or long lasting hydrocephalus may be contributing factors. 23).

Martin et al. studied whether and how frequently patients with ACoA aneurysms present with smell identification deficits in 2 treatment groups (endovascular and surgical treatment).

Methods: A prospective study was conducted of patients with SAH caused by ruptured ACoAs and who had a Glasgow Outcome Scale score of 1 or 2, in comparison with a control group matched by age and sex. Olfactory function was assessed using the University of Pennsylvania Smell Identification Test (UPSIT).

Results: A total of 39 patients were enrolled. A marked olfactory impairment was observed in patients with ruptured ACoAs compared with the control group (p < 0.001). Seventeen patients with ruptured ACoAs (44%) compared with 1 patient in the control group (3%) showed a smell identification deficit according to performance on the UPSIT (p < 0.001). Both groups that underwent treatment presented with olfactory impairment. Ten (59%) of 17 patients who underwent aneurysmal clip placement versus 6 (28.5%) of 21 patients who underwent coil embolization scored below the 25th percentile on the UPSIT, and surgical patients also performed worse than endovascular patients (p = 0.048). The authors observed a worse performance on the olfactory test in patients subjected to endovascular coil embolization when cerebral vasospasm (p = 0.037) or frontal cerebral lesions (p = 0.009) were present. This difference was not observed in patients who underwent surgery.

Conclusions: Olfactory disorders after SAH caused by rupture of the ACoA are very frequent and were present in both treatment groups. Cerebral vasospasm and frontal lobe lesions are related to worse performance on an olfactory test in patients undergoing endovascular coil embolization 24).

To discriminate between the effects of aneurysmal rupture and treatment, Moman et al. assessed the occurrence of anosmia after clipping and coiling of unruptured aneurysms as well as after the coiling of ruptured aneurysms.

Methods: The authors interviewed patients in whom an unruptured aneurysm was treated by clipping (32 cases) or endovascular coiling (26 cases) as well as patients with SAH who underwent coil therapy (32 cases). A geographically defined subset of 20 patients per group was invited to undergo olfactory testing.

Results: Nine clip-treated patients (28% [95% CI 14-47%]) in the unruptured group reported having anosmia, and no coil-treated patient in the unruptured group (95% [CI 0-13%]) reported having anosmia; in the SAH group, 7 patients (22% [95% CI 9-40%]) reported having anosmia. Anosmia had improved over time in 3 of the clip-treated patients and in all but 1 of the patients with SAH. Examination revealed olfactory disturbance in 13 (65% [95% CI 41-85%]) of the clip-treated and 8 (42% [95% CI 20-67%]) of the coil-treated patients with unruptured aneurysms, and also in 7 (35% [95% CI 15-59%]) coil-treated patients with SAH. In 20 patients who underwent clip therapy for unruptured aneurysms, 19 (95% [95% CI 75-100%]) had olfactory dysfunction on the side ipsilateral to surgery (anosmia reported by 8 of them).

Conclusions: Both clip treatment and SAH contribute to the occurrence of anosmia, with different chances of improvement. Olfactory dysfunction occurs in almost all patients on the side of surgery and can occur subclinically after coil deployment. 25).

Wermer et al. studied the prevalence, predisposing factors (aneurysm site and type of treatment), impact, and prognosis of anosmia in patients with SAH.

Of the patients with SAH who resumed independent living, we included all patients treated by coiling between 1997 and 2003 and a sample of patients treated by clipping between 1985 and 2001. Patients underwent structured interviews regarding the presence and duration of anosmia. The impact of anosmia was scored using a visual analog scale ranging from 0 (no influence) to 100 (the worst thing that ever happened to them). Risk factors for anosmia were assessed by logistic regression analysis.

Overall, 89 of the 315 interviewed patients (28%; 95% confidence interval [CI], 23-34%) reported anosmia after SAH (mean follow-up period, 7.4 yr), including 10 (15%) of the 67 coiled patients and 79 (32%) of the 248 clipped patients. The median visual analog scale impact score was 53 (range, 0-100). In 20 of the 89 patients (23%; 95% CI, 15-33), the symptoms had improved over time. Risk factors for anosmia were treatment by clipping (odds ratio [OR], 2.7; 95% CI, 1.3-5.7) and anterior communicating artery aneurysms (OR, 2.0; 95% CI, 1.2-3.3).

Anosmia after SAH has a high prevalence, considerable impact, and poor prognosis. Its occurrence after coiling suggests not only damage to the olfactory nerve by clipping but also that the SAH itself plays a role in its pathogenesis. 26)

Nozaki et al. described a patient with bilateral persistent primitive olfactory arteries associated with an unruptured saccular aneurysm on the left persistent primitive olfactory artery. Seven reported cases with this anomalous artery including ours are reviewed and classified into two variants. This anomalous artery arises from the terminal portion of the internal carotid artery and courses anteromedially along the ipsilateral olfactory tract and makes a hair-pin curve posterior to the olfactory bulb, becoming the distal anterior cerebral artery (variant 1) or the ethmoidal artery (variant 2). Out of 7 reported cases, 4 cases are associated with saccular aneurysms. The aneurysm in variant 1 is located on the hair-pin curve at which an apparent arterial branch is sometimes absent. Two patients suffer from anosmia. Persistent primitive olfactory artery should be kept in mind because of its high association with intracranial saccular aneurysms and unique clinical presentation. 27).

In as retrospective study, 100 patients with anterior communicating artery aneurysms, for whom the pterional approach was employed, were observed from the point of view of postoperative olfactory nerve function. In the postoperative period only three cases suffered from the impaired sense of smell ipsilateral to the side of surgery. 15 patients objectively showed olfactory nerve distinctions. The functions of olfactory nerve could be preserved at a relatively high rate of 85 per cent. This high rate resulted from the microtechnique employed as well as the relatively cautious frontal lobe retraction which was less than 1.5 cm. 28).

Between 1969 and 1994 we treated 450 patients with ruptured anterior communicating artery aneurysms, of which 434 cases (96.4%) were operated on via the interhemispheric approach (IH), namely, until 1979 mainly, via bifrontal craniotomy, subfrontal and interhemispheric approach (SIH) and, since 1979, via posterior interhemispheric approach (PIH). Postoperative olfactory dysfunction is one of the main disadvantages of IH. The mechanisms and the incidence of this disadvantage were studied in both approaches. The causes of postoperative anosmia in SIH were as follows: sectioning of olfactory tracts intentionally or not, avulsion of olfactory bulbs and probability of ischemic or minor mechanical insults to olfactory tracts. However, these matters rarely occur in PIH because of little exposure of olfactory nerves. The mechanisms of postoperative anosmia in PIH were considered to be as follows: sinking of frontal lobes due to excessive drainage of cerebrospinal fluid and over-retraction of frontal lobes. The incidence of postoperative anosmia decreased from 27.0% via SIH to 5.5% via PIH 29).

The olfactory function could be examined in 101 of 138 patients with anterior communicating artery aneurysms, whom we treated during a recent 6-year period. Among them, 49 patients underwent surgery by the anterior interhemispheric approach and 52 underwent surgery by the basal interhemispheric approach. Fifteen patients (31%) exhibited anosmia after surgery by the anterior interhemispheric approach, whereas only one patient (1.9%) exhibited anosmia after surgery by the basal interhemispheric approach. Unilateral dural incision and unilateral brain retraction without elevation of the frontal lobe from the frontal base are important, because frontal lobe depression and elevation during surgery may injure the olfactory nerve 30).

Yasui et al. reviewed the surgical outcome in 85 patients with ruptured anterior communicating artery (ACoA) aneurysms, who were operated on within 72 hours of onset via a basal interhemispheric (BIH) approach (Group 1, N = 48), or an anterior interhemispheric (AIH) approach (Group 2, N = 37). The age, sex ratio and pre-operative grade (Gr) were similar for both groups. The outcome at the time of discharge was as follows for group 1: excellent or good 88%; fair, 6%; vegetative state, 2% and death 4%. For group 2, it was: excellent or good 78%; fair, 16%; vegetative state, 3%; and death, 3%. A significant correlation between admission grade and outcome was found in both groups. The outcome in group 1 was better than in group 2 for patients with a Glasgow Outcome Scale (GOS) better than fair (p < 0.07). No patient in group 1 had postoperative anosmia, but nine patients in group 2 became anosmic. The total number of complications was also significantly less in group 1. Our overall mortality rate was 4%. In conclusion, the BIH approach was more beneficial for treating acute ACoA aneurysm. 31).

In a retrospective study of 25 patients operated on for ruptured intracranial aneurysms via the frontotemporal route, 22 patients suffered postoperatively from anosmia ipsilateral to the side of surgery. This complication most often goes unrecognized by the patient as well as the physician, and attention should be drawn to it because of its widespread occurrence. This investigation demonstrates a high incidence of anosmia (24 (88.9%) of 27 surgical sides) occurring ipsilateral to the frontotemporal approach in aneurysm surgery. Recovery after traumatic anosmia has been recorded up to 5 years after injury. Nevertheless, the authors believe that the damage is permanent when lasting 35 months or longer 32)


Bor AS, Niemansburg SL, Wermer MJ, Rinkel GJ. Anosmia after coiling of ruptured aneurysms: prevalence, prognosis, and risk factors. Stroke. 2009 Jun;40(6):2226-8. doi: 10.1161/STROKEAHA.108.539445. Epub 2009 Apr 16. PMID: 19372449.

Martin GE, Junqué C, Juncadella M, Gabarrós A, de Miquel MA, Rubio F. Olfactory dysfunction after subarachnoid hemorrhage caused by ruptured aneurysms of the anterior communicating artery. Clinical article. J Neurosurg. 2009 Nov;111(5):958-62. doi: 10.3171/2008.11.JNS08827. PMID: 19361265.

Moman MR, Verweij BH, Buwalda J, Rinkel GJ. Anosmia after endovascular and open surgical treatment of intracranial aneurysms. J Neurosurg. 2009 Mar;110(3):482-6. doi: 10.3171/2008.8.JNS08761. PMID: 19072311.

Wermer MJ, Donswijk M, Greebe P, Verweij BH, Rinkel GJ. Anosmia after aneurysmal subarachnoid hemorrhage. Neurosurgery. 2007 Nov;61(5):918-22; discussion 922-3. doi: 10.1227/01.neu.0000303187.34308.7b. PMID: 18091268.
5) , 16)

Park J, Son W, Goh DH, Kang DH, Lee J, Shin IH. Height of aneurysm neck and estimated extent of brain retraction: powerful predictors of olfactory dysfunction after surgery for unruptured anterior communicating artery aneurysms. J Neurosurg. 2016 Mar;124(3):720-5. doi: 10.3171/2015.1.JNS141766. Epub 2015 Aug 14. PMID: 26274995.
6) , 12)

Wongsuriyanan S, Sriamornrattanakul K. Interhemispheric Approach with Early A1 Exposure for Clipping Anterior Communicating Artery Aneurysms: Operative Techniques and Outcomes. World Neurosurg. 2020 Jun;138:e579-e590. doi: 10.1016/j.wneu.2020.03.005. Epub 2020 Mar 9. PMID: 32165343.

Ito S, Fujimoto S, Saito K, Tada H, Tanaka T. [Postoperative olfactory dysfunction in interhemispheric approach for ruptured anterior communicating artery aneurysms]. No Shinkei Geka. 1996 Jul;24(7):625-8. Japanese. PMID: 8752875.
8) , 15)

Cho H, Jo KI, Yeon JY, Hong SC, Kim JS. Feasibility and Efficacy of Olfactory Protection Using Gelfoam and Fibrin Glue during Anterior Communicating Artery Aneurysm Surgery. J Korean Neurosurg Soc. 2015 Aug;58(2):107-11. doi: 10.3340/jkns.2015.58.2.107. Epub 2015 Aug 28. PMID: 26361525; PMCID: PMC4564741.

Aydin IH, Kadioğlu HH, Tüzün Y, Kayaoğlu CR, Takçi E, Oztürk M. Postoperative anosmia after anterior communicating artery aneurysms surgery by the pterional approach. Minim Invasive Neurosurg. 1996 Sep;39(3):71-3. doi: 10.1055/s-2008-1052220. PMID: 8892284.
10) , 30)

Fujiwara H, Yasui N, Nathal-Vera E, Suzuki A. Anosmia after anterior communicating artery aneurysm surgery: comparison between the anterior interhemispheric and basal interhemispheric approaches. Neurosurgery. 1996 Feb;38(2):325-8. doi: 10.1097/00006123-199602000-00017. PMID: 8869060.
11) , 32)

Eriksen KD, Bøge-Rasmussen T, Kruse-Larsen C. Anosmia following operation for cerebral aneurysms in the anterior circulation. J Neurosurg. 1990 Jun;72(6):864-5. doi: 10.3171/jns.1990.72.6.0864. PMID: 2338570.

Hendrix P, Fischer G, Krug J, Linnebach AC, Simgen A, Griessenauer CJ, Burkhardt BW, Oertel J. Olfactory dysfunction in patients undergoing supraorbital keyhole craniotomy for clipping of unruptured aneurysms. Clin Anat. 2020 Mar;33(2):316-323. doi: 10.1002/ca.23529. Epub 2019 Dec 14. PMID: 31769083.

Mori K, Wada K, Otani N, Tomiyama A, Toyooka T, Tomura S, Takeuchi S, Yamamoto T, Nakao Y, Arai H. Long-Term Neurological and Radiological Results of Consecutive 63 Unruptured Anterior Communicating Artery Aneurysms Clipped via Lateral Supraorbital Keyhole Minicraniotomy. Oper Neurosurg (Hagerstown). 2018 Feb 1;14(2):95-103. doi: 10.1093/ons/opx244. PMID: 29228382.

Matano F, Murai Y, Mizunari T, Tateyama K, Kobayashi S, Adachi K, Kamiyama H, Morita A, Teramoto A. Olfactory preservation during anterior interhemispheric approach for anterior skull base lesions: technical note. Neurosurg Rev. 2016 Jan;39(1):63-8; discussion 69. doi: 10.1007/s10143-015-0647-x. Epub 2015 Jul 17. PMID: 26178238.

Lai LT, Gragnaniello C, Morgan MK. Outcomes for a case series of unruptured anterior communicating artery aneurysm surgery. J Clin Neurosci. 2013 Dec;20(12):1688-92. doi: 10.1016/j.jocn.2013.02.015. Epub 2013 Aug 16. PMID: 23958481.

Nakayama H, Ishikawa T, Yamashita S, Fukui I, Mutoh T, Hikichi K, Yoshioka S, Kawai H, Tamakawa N, Moroi J, Suzuki A, Yasui N. [CSF leakage and anosmia in aneurysm clipping of anterior communicating artery by basal interhemispheric approach]. No Shinkei Geka. 2011 Mar;39(3):263-8. Japanese. PMID: 21372335.

Hayashi N, Sato H, Akioka N, Kurosaki K, Hori S, Endo S. Unilateral anterior interhemispheric approach for anterior communicating artery aneurysms with horizontal head position–technical note. Neurol Med Chir (Tokyo). 2011;51(2):160-3. doi: 10.2176/nmc.51.160. PMID: 21358165.

Beseoglu K, Lodes S, Stummer W, Steiger HJ, Hänggi D. The transorbital keyhole approach: early and long-term outcome analysis of approach-related morbidity and cosmetic results. Technical note. J Neurosurg. 2011 Mar;114(3):852-6. doi: 10.3171/2010.9.JNS1095. Epub 2010 Oct 29. PMID: 21029037.

Sieśkiewicz A, Kochanowicz J, Rutkowska J, Rogowski M, Olszewska E. Ocena zaburzeń wechu u chorych po operacji peknietego tetniaka tetnicy łaczacej przedniej mózgu [The evaluation of olfactory dysfunction after the operation of ruptured anterior communicating artery aneurysm]. Pol Merkur Lekarski. 2009 Oct;27(160):302-4. Polish. PMID: 19928658.

Bor AS, Niemansburg SL, Wermer MJ, Rinkel GJ. Anosmia after coiling of ruptured aneurysms: prevalence, prognosis, and risk factors. Stroke. 2009 Jun;40(6):2226-8. doi: 10.1161/STROKEAHA.108.539445. Epub 2009 Apr 16. PMID: 19372449.

Martin GE, Junqué C, Juncadella M, Gabarrós A, de Miquel MA, Rubio F. Olfactory dysfunction after subarachnoid hemorrhage caused by ruptured aneurysms of the anterior communicating artery. Clinical article. J Neurosurg. 2009 Nov;111(5):958-62. doi: 10.3171/2008.11.JNS08827. PMID: 19361265.

Moman MR, Verweij BH, Buwalda J, Rinkel GJ. Anosmia after endovascular and open surgical treatment of intracranial aneurysms. J Neurosurg. 2009 Mar;110(3):482-6. doi: 10.3171/2008.8.JNS08761. PMID: 19072311.

Wermer MJ, Donswijk M, Greebe P, Verweij BH, Rinkel GJ. Anosmia after aneurysmal subarachnoid hemorrhage. Neurosurgery. 2007 Nov;61(5):918-22; discussion 922-3. doi: 10.1227/01.neu.0000303187.34308.7b. PMID: 18091268.

Nozaki K, Taki W, Kawakami O, Hashimoto N. Cerebral aneurysm associated with persistent primitive olfactory artery aneurysm. Acta Neurochir (Wien). 1998;140(4):397-401; discussion 401-2. doi: 10.1007/s007010050114. PMID: 9689332.

Aydin IH, Kadioğlu HH, Tüzün Y, Kayaoğlu CR, Takçi E, Oztürk M. Postoperative anosmia after anterior communicating artery aneurysms surgery by the pterional approach. Minim Invasive Neurosurg. 1996 Sep;39(3):71-3. doi: 10.1055/s-2008-1052220. PMID: 8892284.

Ito S, Fujimoto S, Saito K, Tada H, Tanaka T. [Postoperative olfactory dysfunction in interhemispheric approach for ruptured anterior communicating artery aneurysms]. No Shinkei Geka. 1996 Jul;24(7):625-8. Japanese. PMID: 8752875.

Yasui N, Nathal E, Fujiwara H, Suzuki A. The basal interhemispheric approach for acute anterior communicating aneurysms. Acta Neurochir (Wien). 1992;118(3-4):91-7. doi: 10.1007/BF01401292. PMID: 1456108.

Cervical spondylotic myelopathy surgery outcome

Cervical spondylotic myelopathy surgery outcome

Indications and optimal timing for surgical treatment of degenerative cervical myelopathy (DCM) remain unclear, and data from daily clinical practice are warranted.

Gulati et al. investigated clinical outcomes following decompressive surgery for DCM.

Data were obtained from the Norwegian Registry for Spine Surgery. The primary outcome was change in the neck disability index (NDI) 1 yr after surgery. Secondary endpoints were the European myelopathy score (EMS), quality of life (EuroQoL 5D [EQ-5D]), numeric rating scales (NRS) for headache, neck pain, and arm pain, complications, and perceived benefit of surgery assessed by the Global Perceived Effect scale.

They included 905 patients operated between January 2012 and June 2018. There were significant improvements in all Patient-reported outcome measures (PROMs) including NDI (mean -10.0, 95% CI -11.5 to -8.4, P < .001), EMS (mean 1.0, 95% CI 0.8-1.1, P < .001), EQ-5D index score (mean 0.16, 95% CI 0.13-0.19, P < .001), EQ-5D visual analogue scale (mean 13.8, 95% CI 11.7-15.9, P < .001), headache NRS (mean -1.1, 95% CI -1.4 to -0.8, P < .001), neck pain NRS (mean -1.8, 95% CI -2.0 to -1.5, P < .001), and arm pain NRS (mean -1.7, 95% CI -1.9 to -1.4, P < .001). According to GPE scale assessments, 229/513 patients (44.6%) experienced “complete recovery” or felt “much better” at 1 yr. There were significant improvements in all PROMs for both mild and moderate-to-severe DCM. A total of 251 patients (27.7%) experienced adverse effects within 3 mo.

Surgery for DCM is associated with significant and clinically meaningful improvement across a wide range of PROMs 1).

Objective scoring of the post-operative neurological function did not correlate with patient-perceived outcomes in Degenerative cervical myelopathy outcome (DCM). Traditional testing of motor and sensory function as part of the neurological assessment may not be sensitive enough to assess the scope of neurological changes experienced by Degenerative cervical myelopathy patients 2).

Hamdan assessed the relation between MRI T2 Weighted images (T2WIhyperintense cord signal and clinical outcome after anterior cervical discectomy in patients with degenerative cervical disc herniation.

This retrospective observational study was conducted on twenty-five patients with degenerative cervical disc prolapse associated with MRI T2WI hyperintense cord signal, at the Department of Neurosurgery, Qena University Hospital, South Valley University from August 2014 to December 2016. A complete clinical and radiological evaluation of the patients was done. Anterior cervical discectomy and fusion was done for all patients. Patients were clinically assessed preoperatively and postoperatively at 3, 6, and 12 months using Modified Japanese Orthopaedic Association scale (MJOA). Radiographic assessment was done by preoperative and postoperative T2WI MRI. The statistical analysis was done using Statistical Package for the Social Sciences (SPSS) software (version 22.0).

There were 25 patients included in the study; 16 (64%) females and 9 (36%) males. The mean age was 46.89 ± 7.52 standard deviation (SD) years with range from 26 to 64 years, 3 (12%) patients had worsened in the form of postoperative motor power deterioration, and 14 (56%) patients has no improvement and remain as preoperative condition. The remaining 8 (32%) patients had a reported postoperative improvement of symptoms and signs according to MJOA score. The mean follow-up period (in months) was 11 ± 2.34 (SD). Conclusion:

The presence of T2W hyperintense signal on preoperative MRI predicts a poor surgical outcome in patients with cervical disc prolapse. The regression of T2W ISI postoperatively correlates with better functional outcomes 3).

Whilst decompressive surgery can halt disease progression, existing spinal cord damage is often permanent, leaving patients with lifelong disability.

Early surgery improves the likelihood of recovery, yet the average time from onset of symptoms to correct diagnosis is over 2 years. The majority of delays occur initially, before and within primary care, mainly due to a lack of recognition. Symptom checkers are widely used by patients before medical consultation and can be useful for preliminary triage and diagnosis. Lack of recognition of Degenerative Cervical Myelopathy (DCM) by symptom checkers may contribute to the delay in diagnosis.

The impact of the changes in myelopathic signs following cervical decompression surgery and their relationship to functional outcome measures remains unclear.

Surgery is associated with a significant quality of life improvement. The intervention is cost effective and, from the perspective of the hospital payer, should be supported 4).

Surgical decompression for CSM is safe and results in improved functional status and quality of life in patients around the world, irrespective of differences in medical systems and socio-cultural determinants of health 5).

The successful management of CSM depends upon an early and accurate diagnosis, an objective assessment of impairment and disability, and an ability to predict outcome. In this field, quantitative measures are increasingly used by clinicians to grade functional and neurological status and to provide decision-making support 6).

In addition, objective assessment tools allow clinicians to quantify myelopathy severity, predict outcome, and evaluate surgical benefits by tracking improvements throughout follow-up 7) 8) 9).

Several outcome measures assess functional impairment and quality of life in patients with cervical myelopathy 10) 11) 12) 13) 14).

A validated “gold standard,” however, has not been established, preventing the development of quantitative guidelines for CSM management 15).

In this field, one of the most widely accepted tool for assessing functional status is the modified Japanese Orthopaedic Association scale (mJOA).

Some studies have found that resolution of T2 hyperintensity in subjects with CSM who undergo ventral decompressive surgery correlates with improved functional outcomes. Other studies have found little correlation with postoperative outcome 16) 17).

Machine learning for degenerative cervical myelopathy

see Machine learning for degenerative cervical myelopathy.


1) Gulati S, Vangen-Lønne V, Nygaard ØP, Gulati AM, Hammer TA, Johansen TO, Peul WC, Salvesen ØO, Solberg TK. Surgery for Degenerative Cervical Myelopathy: A Nationwide Registry-Based Observational Study With Patient-Reported Outcomes. Neurosurgery. 2021 Jul 29:nyab259. doi: 10.1093/neuros/nyab259. Epub ahead of print. PMID: 34325471.2) McGregor SM, Detombe S, Goncalves S, Doyle-Pettypiece P, Bartha R, Duggal N. Does the Neurological Exam Correlate with Patient Perceived Outcomes in Degenerative Cervical Myelopathy? World Neurosurg. 2019 Aug 2. pii: S1878-8750(19)32111-4. doi: 10.1016/j.wneu.2019.07.195. [Epub ahead of print] PubMed PMID: 31382071.3) Hamdan ARK. The Relation between Cord Signal and Clinical Outcome after Anterior Cervical Discectomy in Patients with Degenerative Cervical Disc Herniation. Asian J Neurosurg. 2019 Jan-Mar;14(1):106-110. doi: 10.4103/ajns.AJNS_262_17. PubMed PMID: 30937019; PubMed Central PMCID: PMC6417293.4) Witiw CD, Tetreault LA, Smieliauskas F, Kopjar B, Massicotte EM, Fehlings MG. Surgery for degenerative cervical myelopathy: a patient centered quality of life and health economic evaluation. Spine J. 2016 Oct 25. pii: S1529-9430(16)31022-1. doi: 10.1016/j.spinee.2016.10.015. [Epub ahead of print] PubMed PMID: 27793760.5) Fehlings MG, Ibrahim A, Tetreault L, Albanese V, Alvarado M, Arnold P, Barbagallo G, Bartels R, Bolger C, Defino H, Kale S, Massicotte E, Moraes O, Scerrati M, Tan G, Tanaka M, Toyone T, Yukawa Y, Zhou Q, Zileli M, Kopjar B. A Global Perspective on the Outcomes of Surgical Decompression in Patients with Cervical Spondylotic Myelopathy: Results from the Prospective Multicenter AOSpine International Study on 479 patients. Spine (Phila Pa 1976). 2015 May 27. [Epub ahead of print] PubMed PMID: 26020847.6) , 15) Singh A, Tetreault L, Casey A, et al. A summary of assessment tools for patients suffering from cervical spondylotic myelopathy: a systematic review on validity, reliability, and responsiveness [published online ahead of print September 5, 2013]. Eur Spine J. doi:10.1007/s00586-013-2935-x.7) Laing RJ. Measuring outcome in neurosurgery. Br J Neurosurg 2000;14:181–4.8) Holly LT, Matz PG, Anderson PA, et al. Clinical prognostic indicators of surgical outcome in cervical spondylotic myelopathy. J Neurosurg Spine 2009;11:112–8.9) Kalsi-Ryan S, Singh A, Massicotte EM, et al. Ancillary outcome measures for assessment of individuals with cervical spondylotic myelopathy. Spine (Phila Pa 1976) 2013;38:S111–22.10) Singh A, Crockard HA. Quantitative assessment of cervical spondylotic myelopathy by a simple walking test. Lancet 1999;354:370–3.11) Nurick S. The natural history and the results of surgical treatment of the spinal cord disorder associated with cervical spondylosis. Brain 1972;95:101–8.12) Olindo S, Signate A, Richech A, et al. Quantitative assessment of hand disability by the nine-hole-peg test (9-HPT) in cervical spondylotic myelopathy. J Neurol Neurosurg Psychiatry 2008;79:965–7.13) Hosono N, Sakaura H, Mukai Y, et al. A simple performance test for quantifying the severity of cervical myelopathy [erratum in: J Bone Joint Surg Br 2008;90:1534]. J Bone Joint Surg Br 2008;90:1210–3.14) Casey AT, Bland JM, Crockard HA. Development of a functional scoring system for rheumatoid arthritis patients with cervical myelopathy. Ann Rheum Dis 1996;55:901–6.16) Sarkar S, Turel MK, Jacob KS, Chacko AG. The evolution of T2-weighted intramedullary signal changes following ventral decompressive surgery for cervical spondylotic myelopathy. J Neurosurg Spine. 2014;21(4):538-546.17) Vedantam A, Rajshekhar V. Change in morphology of intramedullary T2- weighted increased signal intensity after anterior decompressive surgery for cervical spondylotic myelopathy. Spine (Phila Pa 1976). 2014;39(18):1458-1462.

Convexity meningioma surgery

Convexity meningioma surgery

Convexity meningioma surgery indications.

Preoperative embolization of intracranial meningioma.

see Surgical safety checklist.

see Preoperative antibiotic prophylaxis.

see Skin Preparation.

For convexity meningioma, the head is positioned so that the center of the tumor is uppermost, the same position as described for parasagittal tumors or for tumors close to the midline.

The incision and bone flap must be large enough to allow for excision of a good margin of dura around the tumor attachments.

The meningeal arteries are occluded as they are exposed.

These tumors can be removed intact by placing gentle traction on the dural attachment and working circumferentially around the tumor to divide the attachments to the cortex. However, if the surface of the tumor cannot be easily visualized without placing significant retraction on the cortex, internal decompression of the tumor is done and the capsule is reflected into the area of decompression.

In a situation where the tumor arises over the frontal temporal junction and grows into the sylvian fissure, the medial capsule and the dural attachment may extend down onto the lateral floor of the anterior fossa and anterior wall of the middle fossa, and the medial capsule of the tumor can be attached to branches of the middle cerebral artery.

A study showed that meningioma recurrence was unlikely when autologous cranioplasty was done with refashioned hyperostotic bone. This could be done in the same setting with meningioma excision. There was no recurrence at a mean of 5-year follow-up in convexity meningiomas 1).

Right Convexity Meningioma from Surgical Neurology International on Vimeo.

Left Frontal Convexity Meningioma from Surgical Neurology International on Vimeo.

An accurate and real-time model of soft tissue is critical for surgical simulation for which a user interacts haptically and visually with simulated patients. A paper focuses on the real-time deformation model of brain tissue for the interactive surgical simulation, such as neurosurgical simulation.

A new Finite Element Method (FEM) based model with constraints is proposed for the brain tissue in neurosurgical simulation. A new energy function of constraints characterizing the interaction between the virtual instrument and the soft tissue is incorporated into the optimization problem derived from the implicit integration scheme. Distance and permanent deformation constraints are introduced to describe the interaction in the convexity meningioma dissection and hemostasis. The proposed model is particularly suitable for GPU-based computing, making it possible to achieve real-time performance.

Simulation results show that the simulated soft tissue exhibits the behaviors of adhesion and permanent deformation under the constraints. Experiments show that the proposed model is able to converge to the exact solution of the implicit Euler method after 96 iterations. The proposed model was implemented in the development of a neurosurgical simulator, in which surgical procedures such as dissection of convexity meningioma and hemostasis were simulated 2).


Lau BL, Che Othman MI, Fakhri M, San Liew DN, San Lim S, Bujang MA, Hieng Wong AS. Does putting back hyperostotic bone flap in meningioma surgery causes tumor recurrence? An observational prospective study. World Neurosurg. 2019 Mar 26. pii: S1878-8750(19)30863-0. doi: 10.1016/j.wneu.2019.03.183. [Epub ahead of print] PubMed PMID: 30926555.

Hou W, Liu PX, Zheng M. A new model of soft tissue with constraints for interactive surgical simulation. Comput Methods Programs Biomed. 2019 Jul;175:35-43. doi: 10.1016/j.cmpb.2019.03.018. Epub 2019 Apr 1. PubMed PMID: 31104713.

Michigan Spine Surgery Improvement Collaborative

Michigan Spine Surgery Improvement Collaborative


The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a statewide quality improvement collaborative involving orthopedic surgeons and neurosurgeons with the aim of improving the quality of care of spine surgery. The objective of this collaborative is to heighten patient care outcomes while consequently increasing the efficiency of treatment.

The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a prospectivelongitudinalmulticenterquality-improvement collaborative.

Michigan Spine Surgery Improvement Collaborative (MSSIC) prospectively collects data on all patients undergoing operations for degenerative and/or deformity indications.

In 2013, Blue Cross Blue Shield of Michigan (BCBSM) and Blue Care Network (BCN) established the Michigan Spine Surgery Improvement Collaborative (MSSIC) as a Collaborative Quality Initiative (CQI). MSSIC is one of the newest of 21 other CQIs that have significantly improved and continue to improve the quality of patient care throughout the state of Michigan. METHODS MSSIC focuses on lumbar and cervical spine surgery, specifically indications such as stenosis, disk herniation, and degenerative disease. Surgery for tumors, traumatic fractures, deformity, scoliosis, and acute spinal cord injury are currently not within the scope of MSSIC. Starting in 2014, MSSIC consisted of 7 hospitals and in 2015 included another 15 hospitals, for a total of 22 hospitals statewide. A standardized data set is obtained by data abstractors, who are funded by BCBSM/BCN. Variables of interest include indications for surgery, baseline patient-reported outcome measures, and medical history. These are obtained within 30 days of surgery. Outcome instruments used include the EQ-5D general health state score (0 being worst and 100 being the best health one can imagine) and EQ-5D-3 L. For patients undergoing lumbar surgery, a 0 to 10 numeric rating scale for leg and back pain and the Oswestry Disability Index for back pain are collected. For patients undergoing cervical surgery, a 0 to 10 numeric rating scale for arm and neck pain, Neck Disability Index, and the modified Japanese Orthopaedic Association score are collected. Surgical details, postoperative hospital course, and patient-reported outcome measures are collected at 90-day, 1-year, and 2-year intervals. RESULTS As of July 1, 2015, a total of 6397 cases have been entered into the registry. This number reflects 4824 eligible cases with confirmed surgery dates. Of these 4824 eligible cases, 3338 cases went beyond the 120-day window and were considered eligible for the extraction of surgical details, 90-day outcomes, and adverse events. Among these 3338 patients, there are a total of 2469 lumbar cases, 862 cervical cases, and 7 combined procedures that were entered into the registry.

In addition to functioning as a registry, MSSIC is also meant to be a platform for quality improvement with the potential for future initiatives and best practices to be implemented statewide in order to improve quality and lower costs. With its current rate of recruitment and expansion, MSSIC will provide a robust platform as a regional prospective registry. Its unique funding model, which is supported by BCBSM/BCN, will help ensure its longevity and viability, as has been observed in other CQIs that have been active for several years 1).

Macki et al. aimed to identify which factors are significantly associated with return-to-work after lumbar surgery at long-term follow-up.

Summary of background data: Prior publications have created a clinically relevant predictive model for return-to-work, wherein educationgenderrace, comorbidities, and preoperative symptoms increased the likelihood of return-to-work at 3 months after lumbar surgery. They sought to determine if these trends 1) persisted at 1 year and 2 years postoperatively, or 2) differed among preoperatively employed versus unemployed patients.

MSSIC was queried for all patients undergoing lumbar operations (2014-2019). All patients intended to return to work postoperatively. Patients were followed for up to 2 years postoperatively. Measures of association were calculated with multivariable generalized estimating equations (GEE).

Return-to-work increased from 63% (3542/5591) at 90 days postoperatively to 75% (3143/4147) at 1 year and 74% (2133/2866) at 2 years postoperatively. Following GEE, neither clinical nor surgical variables predicted return-to-work at all three-time intervals: 90 days, 1 year, and 2 years postoperatively. Only socioeconomic factors reached statistical significance at all follow-up points. Preoperative employment followed by insurance status had the greatest associations with return-to-work. In a sub-analysis of patients who were preoperatively employed, insurance was the only factor with significant associations with return-to-work at all three follow-up intervals. The return-to-work rates among unemployed patients at baseline increased from 29% (455/1100) at 90 days, 44% (495/608) at 1 year, and 46% (366/426) at 2 years postoperatively. The only two significant factors associated with return-to-work at all three follow-up intervals were Medicaid, as compared to private insurance, and male gender.

In patients inquiring about long-term return-to-work after lumbar surgery, health insurance status represents the important determinant of employment status.Level of Evidence: 2 2).

While a complex myriad of socio-economic factors interplay between race and surgical success, they identified modifiable risk factors, specifically depression, that may improve patient-reported outcomes (PROs) among African American patients after elective lumbar spine surgery 3).

Correction of sagittal balance is associated with greater odds of discharge to home. These findings, coupled with the recognized implications of admission to a rehabilitation facility, will emphasize the importance of spine surgeons accounting for the sagittal vertical axis (SVA) in their surgical planning of MIS lumbar interbody fusions 4)

Using MSSIC, Zakaria et al. sought to identify the relationship between a positive Patient Health Questionnaire-2 (PHQ-2) screening, which is predictive of depression, and patient satisfactionreturn to work, and achieving Oswestry Disability Index (ODI) minimal clinically important difference (MCID) scores up to 2 years after lumbar fusion.

Data from a total of 8585 lumbar fusion patients were analyzed. Patient satisfaction was measured by the North American Spine Society patient satisfaction index. A positive PHQ-2 score is one that is ≥ 3, which has an 82.9% sensitivity and 90.0% specificity in detecting major depressive disorder. Generalized estimating equation models were constructed; variables tested include age, sex, race, past medical history, severity of surgery, and preoperative opioid usage.

Multivariate analysis was performed. Patients with a positive PHQ-2 score (i.e., ≥ 3) were less likely to be satisfied after lumbar fusion at 90 days (relative risk [RR] 0.93, p < 0.001), 1 year (RR 0.92, p = 0.001), and 2 years (RR 0.92, p = 0.028). A positive PHQ-2 score was also associated with decreased likelihood of returning to work at 90 days (RR 0.76, p < 0.001), 1 year (RR 0.85, p = 0.001), and 2 years (RR 0.82, p = 0.031). A positive PHQ-2 score was predictive of failure to achieve an ODI MCID at 90 days (RR 1.07, p = 0.005) but not at 1 year or 2 years after lumbar fusion.

A multivariate analysis based on information from a large, multicenter, prospective database on lumbar fusion patients was performed. The authors found that a positive score (≥ 3) on the PHQ-2, which is a simple and accurate screening tool for depression, predicts an inability to return to work and worse satisfaction up to 2 years after lumbar fusion. Depression is a treatable condition, and so in the same way that patients are medically optimized before surgery to decrease postoperative morbidity, perhaps patients should have preoperative psychiatric optimization to improve postoperative functional outcomes 5).

Ninety-day readmission occurred in 9.0% of patients, mainly for painwound infection, and radicular symptoms. Increased focus on postoperative pain may decrease readmissions. Among factors impacting the likelihood of 90-d readmission, early postoperative ambulation may be most easily modifiable. Optimization of preexisting medical conditions could also potentially decrease readmission risk 6).

Multivariate analysis identified the common adverse events after cervical spine surgery, along with their associated risk factors. They found that early mobilization after cervical spine surgery has the potential to significantly decrease adverse events 7).


Chang V, Schwalb JM, Nerenz DR, Pietrantoni L, Jones S, Jankowski M, Oja-Tebbe N, Bartol S, Abdulhak M. The Michigan Spine Surgery Improvement Collaborative: a statewide Collaborative Quality Initiative. Neurosurg Focus. 2015 Dec;39(6):E7. doi: 10.3171/2015.10.FOCUS15370. PMID: 26621421.

Macki M, Anand SK, Hamilton T, Lim S, Mansour T, Bazydlo M, Schultz L, Abdulhak MM, Khalil JG, Park P, Aleem I, Easton R, Schwalb JM, Nerenz D, Chang V. Analysis of Factors associated with Return to Work After Lumbar Surgery up to 2-years follow-up: A Michigan Spine Surgery Improvement Collaborative (MSSIC) Study. Spine (Phila Pa 1976). 2021 Jul 7. doi: 10.1097/BRS.0000000000004163. Epub ahead of print. PMID: 34265812.

Macki M, Hamilton T, Lim S, Telemi E, Bazydlo M, Nerenz DR, Zakaria HM, Schultz L, Khalil JG, Perez-Cruet MJ, Aleem IS, Park P, Schwalb JM, Abdulhak MM, Chang V. Disparities in outcomes after spine surgery: a Michigan Spine Surgery Improvement Collaborative study. J Neurosurg Spine. 2021 May 7:1-9. doi: 10.3171/2020.10.SPINE20914. Epub ahead of print. PMID: 33962387.

Macki M, Fadel HA, Hamilton T, Lim S, Massie LW, Zakaria HM, Pawloski J, Chang V. The influence of sagittal spinopelvic alignment on patient discharge disposition following minimally invasive lumbar interbody fusion. J Spine Surg. 2021 Mar;7(1):8-18. doi: 10.21037/jss-20-596. PMID: 33834123; PMCID: PMC8024762.

Zakaria HM, Mansour TR, Telemi E, Asmaro K, Macki M, Bazydlo M, Schultz L, Nerenz DR, Abdulhak M, Schwalb JM, Park P, Chang V. Use of Patient Health Questionnaire-2 scoring to predict patient satisfaction and return to work up to 1 year after lumbar fusion: a 2-year analysis from the Michigan Spine Surgery Improvement Collaborative. J Neurosurg Spine. 2019 Aug 23:1-8. doi: 10.3171/2019.6.SPINE1963. [Epub ahead of print] PubMed PMID: 31443085.

Park P, Nerenz DR, Aleem IS, Schultz LR, Bazydlo M, Xiao S, Zakaria HM, Schwalb JM, Abdulhak MM, Oppenlander ME, Chang VW. Risk Factors Associated With 90-Day Readmissions After Degenerative Lumbar Fusion: An Examination of the Michigan Spine Surgery Improvement Collaborative (MSSIC) Registry. Neurosurgery. 2019 Sep 1;85(3):402-408. doi: 10.1093/neuros/nyy358. PMID: 30113686.

Zakaria HM, Bazydlo M, Schultz L, Pahuta MA, Schwalb JM, Park P, Aleem I, Nerenz DR, Chang V; MSSIC Investigators. Adverse events and their risk factors 90 days after cervical spine surgery: analysis from the Michigan Spine Surgery Improvement Collaborative. J Neurosurg Spine. 2019 Feb 15:1-13. doi: 10.3171/2018.10.SPINE18666. Epub ahead of print. PMID: 30771759.