nerve

Occipital nerve stimulation for cluster headache

Occipital nerve stimulation for cluster headache

Occipital nerve stimulation (ONS) has been proposed chronic cluster headache treatment (rCCH) but its efficacy has only been showed in small short-term series.

Leplus et al. evaluated 105 patients with rCCH, treated by ONS within a multicenter ONS prospective registry. Efficacy was evaluated by frequency, intensity of pain attacks, quality of life (QoL) EuroQol 5 dimensions (EQ5D), functional (Headache Impact Test-6, Migraine Disability Assessment) and emotional (Hospital Anxiety Depression Scale [HAD]) impacts, and medication consumption.

At last follow-up (mean 43.8 mo), attack frequency was reduced >50% in 69% of the patients. Mean weekly attack frequency decreased from 22.5 at baseline to 9.9 (P < .001) after ONS. Preventive and abortive medications were significantly decreased. Functional impact, anxiety, and QoL significantly improved after ONS. In excellent responders (59% of the patients), attack frequency decreased by 80% and QoL (EQ5D visual analog scale) dramatically improved from 37.8/100 to 73.2/100. When comparing baseline and 1-yr and last follow-up outcomes, efficacy was sustained over time. In multivariable analysis, low preoperative HAD-depression score was correlated to a higher risk of ONS failure. During the follow-up, 67 patients experienced at least one complication, 29 requiring an additional surgery: infection (6%), lead migration (12%) or fracture (4.5%), hardware dysfunction (8.2%), and local pain (20%).

The results showed that long–term efficacy of ONS in CCH was maintained over time. In responders, ONS induced a major reduction of functional and emotional headache-related impacts and a dramatic improvement of QoL. These results obtained in real-life conditions support its use and dissemination in rCCH patients 1).

33 patients, of whom 16 had chronic migraine (CM), nine had chronic cluster headache (CCH), and six had secondary headache disorders. PENS was given using Algotec® disposable 21 gauge PENS therapy probes (8 cm) to the occipital nerve ipsilateral to the pain (or bilaterally in cases of bilateral pain). Stimulation was delivered at 2 Hz/100 Hz, at 3 cycles/s, between 1.2 and 2.5 V depending on patient tolerability, for 25-28 min.

Six of nine patients with CCH improved significantly after the first session. In all patients with CCH, PENS therapy was well tolerated, with no significant adverse events reported. One patient with CCH reverted to an episodic cluster. Only four patients with CM experienced any benefit.

PENS therapy shows potential as a relatively non-invasive, low-risk, and inexpensive component of the treatment options for refractory primary headache disorders, particularly CCH 2).

Seventeen patients (12 CM and 5 CCH) were treated with bilateral burst pattern ONS, including 4 who had previously had tonic ONS. Results were assessed in terms of the frequency of headaches (number of headache days per month for CM, and number of attacks per day for CCH) and their intensity on the numeric pain rating scale.

Burst ONS produced a statistically significant mean reduction of 10.2 headache days per month in CM. In CCH, there were significant mean reductions in headache frequency (92%) and intensity (42%).

Paraesthesia is not necessary for good quality analgesia in ONS. Larger studies will be required to determine whether the efficacies of the two stimulation modes differ. Burst ONS is imperceptible and therefore potentially amenable to robustly blinded clinical trials 3).

Eight patients with medically intractable chronic cluster headache were implanted in the suboccipital region with electrodes for occipital nerve stimulation. Other than the first patient, who was initially stimulated unilaterally before being stimulated bilaterally, all patients were stimulated bilaterally during treatment.

At a median follow-up of 20 months (range 6-27 months for bilateral stimulation), six of eight patients reported responses that were sufficiently meaningful for them to recommend the treatment to similarly affected patients with chronic cluster headache. Two patients noticed a substantial improvement (90% and 95%) in their attacks; three patients noticed a moderate improvement (40%, 60%, and 20-80%) and one reported mild improvement (25%). Improvements occurred in both frequency and severity of attacks. These changes took place over weeks or months, although attacks returned in days when the device malfunctioned (eg, with battery depletion). Adverse events of concern were lead migrations in one patient and battery depletion requiring replacement in four.

Occipital nerve stimulation in cluster headache seems to offer a safe, effective treatment option that could begin a new era of neurostimulation therapy for primary headache syndromes 4).

References

1)

Leplus A, Fontaine D, Donnet A, Regis J, Lucas C, Buisset N, Blond S, Raoul S, Guegan-Massardier E, Derrey S, Jarraya B, Dang-Vu B, Bourdain F, Valade D, Roos C, Creach C, Chabardes S, Giraud P, Voirin J, Bloch J, Colnat-Coulbois S, Caire F, Rigoard P, Tran L, Cruzel C, Lantéri-Minet M; French ONS registry group. Long–Term Efficacy of Occipital Nerve Stimulation for Medically Intractable Cluster Headache. Neurosurgery. 2020 Sep 28:nyaa373. doi: 10.1093/neuros/nyaa373. Epub ahead of print. PMID: 32985662.
2)

Weatherall MW, Nandi D. Percutaneous electrical nerve stimulation (PENS) therapy for refractory primary headache disorders: a pilot study. Br J Neurosurg. 2019 Oct 3:1-5. doi: 10.1080/02688697.2019.1671951. [Epub ahead of print] PubMed PMID: 31578882.
3)

Garcia-Ortega R, Edwards T, Moir L, Aziz TZ, Green AL, FitzGerald JJ. Burst Occipital Nerve Stimulation for Chronic Migraine and Chronic Cluster Headache. Neuromodulation. 2019 Jul;22(5):638-644. doi: 10.1111/ner.12977. Epub 2019 Jun 14. PubMed PMID: 31199547.
4)

Burns B, Watkins L, Goadsby PJ. Treatment of medically intractable cluster headache by occipital nerve stimulation: long–term follow-up of 8 patients. Lancet. 2007; 369:1099–1106

Recurrent laryngeal nerve palsy

Recurrent laryngeal nerve palsy

Vocal cord paresis, also known as recurrent laryngeal nerve paralysis or vocal fold paralysis, is an injury to one or both recurrent laryngeal nerves (RLNs), which control all muscles of the larynx except for the cricothyroid muscle. The RLN is important for speaking, breathing and swallowing.

Recurrent laryngeal nerve palsy (RLNP) is a potential complication of anterior cervical discectomy and fusion (ACDF).

While performing the anterior cervical approach, injury to important anatomic structures in the vicinity of the dissection represents a serious risk. The midportion of the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve are encountered in the anterior approach to the lower cervical spine. The recurrent laryngeal nerve is vulnerable to injury on the right side, especially if ligation of inferior thyroid vessels is performed without paying sufficient attention to the course and position of the nerve, and the external branch of the superior laryngeal nerve is vulnerable to injury during ligature and division of the superior thyroid artery. Avoiding injury to the recurrent laryngeal nerve (especially on the right side) and superior laryngeal nerve is a major consideration in the anterior approach to the lower cervical spine. The sympathetic trunk is situated in close proximity to the medial border of the longus colli muscle at the C6 level (the longus colli diverge laterally, whereas the sympathetic trunk converges medially). The damage leads to the development of Horner’s syndrome with its associated ptosis, meiosis, and anhydrosis. Awareness of the regional anatomy of the sympathetic trunk may help in identifying and preserving this important structure while performing anterior cervical surgery or during exposure of the transverse foramen or uncovertebral joint at the lower cervical levels. Finally, the spinal accessory nerve (embedded in fibroadipose tissue in the posterior triangle of the neck) is prone to injury. Its damage will result in an obvious shoulder droop, loss of shoulder elevation, and pain. Prevention of inadvertant injury to the accessory nerve is critical in the neck dissection 1).

The rate of RLN palsy of 14.1% was greater than any published rate of RLN injury after primary ACDF operations, suggesting that there is a greater risk of hoarseness and dysphagia with reoperative ACDF surgeries than with primary procedures as reported in these studies 2).

The cervical spine is approached from the right side unless the patient has undergone a prior approach from the left side. If so, the original incision line is used. If a patient has subclinical vocal cord palsy on the side of the incision, proceeding with an incision on the opposite side is risky. The potential for recurrent laryngeal nerve palsy is highest on the right side, although the risk has not been documented in recent reports. The thoracic duct, however, can be injured when the approach is from the left side.

For C5–6, the skin incision is made at level of criccoid cartilage, for other levels, appropriate adjustments up or down may be made, sometimes with the assistance of fluoroscopy. The incision is approximately 4–5cm horizontally, centered on the SCM. Many right handed surgeons prefer operating from the right side of the neck, although the risk to the recurrent laryngeal nerve (RLN) is lower with a left sided approach (the RLN lies in a groove between the esophagus and trachea). The skin may be undermined off the platysma to permit a ver- tical incision in the platysma in the same orientation as its muscle fibers. Alternatively, some incise the platysma horizontally with scissors horizontally.

There still is substantial disagreement on the actual prevalence of RLNP after ACDF as well as on risk factors for postoperative RLNP 3).

Case series

The aim of a study of Huschbeck et al. was to describe the prevalence of postoperative RLNP in a cohort of consecutive cases of ACDF and to examine potential risk factors.

This retrospective study included patients who underwent ACDF between 2005 and 2019 at a single neurosurgical center. As part of clinical routine, RLNP was examined prior to and after surgery by independent otorhinolaryngologists using endoscopic laryngoscopy. As potential risk factors for postoperative RLNP, they examined patient’s age, sex, body mass index, multilevel surgery, and the duration of surgery.

214 consecutive cases were included. The prevalence of preoperative RLNP was 1.4% (3/214) and the prevalence of postoperative RLNP was 9% (19/211). The number of operated levels was 1 in 73.5% (155/211), 2 in 24.2% (51/211), and 3 or more in 2.4% (5/211) of cases. Of all cases, 4.7% (10/211) were repeat surgeries. There was no difference in the prevalence of RLNP between the primary surgery group (9.0%, 18/183) versus the repeat surgery group (10.0%, 1/10; p = 0.91). Also, there was no difference in any characteristics between subjects with postoperative RLNP compared with those without postoperative RLNP. We found no association between postoperative RLNP and patient’s age, sex, body mass index, duration of surgery, or number of levels (odds ratios between 0.24 and 1.05; p values between 0.20 and 0.97).

In this cohort, the prevalence of postoperative RLNP after ACDF was 9.0%. The fact that none of the examined variables was associated with the occurrence of RLNP supports the view that postoperative RLNP may depend more on direct mechanical manipulation during surgery than on specific patient or surgical characteristics 4).

A prospective cohort study conducted on 90 patients scheduled for anterior cervical spine surgeries underwent consecutive pre and postoperative vocal cord examination for edema and paralysis by both anterior and lateral approaches laryngeal ultrasonography. Rigid laryngoscopy was the standard confirmatory tool. For postoperative vocal cord edema, the anterior ultrasonography approach diagnostic sensitivity = 88.2%, specificity = 78.9% with PPV = 78.9% and NPV = 88.2% and the novel lateral ultrasonography approach diagnostic sensitivity = 88.2%, specificity = 94.7% with PPV = 93.75% and NPP = 90%. While for paralysis, the anterior ultrasonography approach diagnostic sensitivity = 86.7%, specificity = 85.7% with PPV = 81.25% and NPV = 90% and the novel lateral ultrasonography approach diagnostic (sensitivity, specificity with PPV and NPP) = 100%. The diagnostic accuracy of the novel lateral approach was more correlated to rigid laryngoscopy (91.7% and 100%) compared to anterior approach for vocal cord edema and paralysis (83.3% and 80.6%). Overall incidence of vocal cord paralysis was 16.6%. Risk of vocal cord paralysis was statistically significant more in female, multiple disc herniation, lower and mixed disc levels, Langenbeck retractor, cage and plate and duration of surgery ≥ 1.5 h. Transcutaneous Laryngeal ultrasound is a valid comfortable tool for prediction of vocal cord edema and paralysis after anterior cervical spine surgeries with superiority of the novel lateral over anterior approach 5).

A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in a retrospective, case-control study. The diagnosis was cervical radiculopathy, and/or myelopathy due to degenerative disc disease, cervical spondylosis, or traumatic cervical spine injury. All our participants underwent surgical treatment, and complications were recorded. The most commonly performed procedure (79%) was anterior cervical discectomy and fusion (ACDF). Fourteen patients (12.3%) underwent anterior cervical corpectomy and interbody fusion, seven (6.1%) ACDF with plating, two (1.7%) odontoid screw fixation, and one anterior removal of osteophytes for severe Forestier’s disease. Mean follow-up time was 42.5 months (range, 6-78 months). The overall complication rate was 13.2%. Specifically, we encountered adjacent intervertebral disc degeneration in 2.7% of our cases, dysphagia in 1.7%, postoperative soft tissue swelling and hematoma in 1.7%, and dural penetration in 1.7%. Additionally, esophageal perforation was observed in 0.9%, aggravation of preexisting myelopathy in 0.9%, symptomatic recurrent laryngeal nerve palsy in 0.9%, mechanical failure in 0.9%, and superficial wound infection in 0.9%. In the vast majority anterior cervical spine surgery-associated complications are minor, requiring no further intervention. Awareness, early recognition, and appropriate management, are of paramount importance for improving the patients’ overall functional outcome 6).

Staartjes et al. analyzed a prospective registry of all consecutive patients undergoing zero-profile ACDF for disc herniation, myelopathy, or stenosis. RLN palsy was defined as persistent patient self-reported dysphagia, hoarseness, or respiratory problems without other identifiable causes. RLN palsy was assessed at scheduled 6-week telephone interviews.

Results: Among 525 included patients, 511 primary and 40 secondary ACDF procedures were performed. Hoarseness was present in 12 (2.2%) cases, whereas dysphagia and respiratory difficulties both occurred in 3 (0.5%) cases. Overall incidence of RLN palsy was 2% after primary procedures and 8% after secondary procedures (P = 0.017). These rates are in line with the peer-reviewed literature, and the difference remained significant after controlling for confounders in a multivariate model (P = 0.033). Other reported risk factors, such as age, sex, surgical time, and multilevel procedures, had no relevant effect (P > 0.05).

Based on our data and other published series in the literature, RLN palsy may occur more frequently after secondary ACDF procedures with a clinically relevant effect size. There is a striking lack of uniformity in methods and reporting in research on RLN injury. 7).

References

1)

Lu J, Ebraheim NA, Nadim Y, Huntoon M. Anterior approach to the cervical spine: surgical anatomy. Orthopedics. 2000 Aug;23(8):841-5. Review. PubMed PMID: 10952048.
2)

Erwood MS, Hadley MN, Gordon AS, Carroll WR, Agee BS, Walters BC. Recurrent laryngeal nerve injury following reoperative anterior cervical discectomy and fusion: a meta-analysis. J Neurosurg Spine. 2016 Aug;25(2):198-204. doi: 10.3171/2015.9.SPINE15187. Epub 2016 Mar 25. PubMed PMID: 27015129.
3) , 4)

Huschbeck A, Knoop M, Gahleitner A, et al. Recurrent Laryngeal Nerve Palsy after Anterior Cervical Discectomy and Fusion – Prevalence and Risk Factors [published online ahead of print, 2020 Aug 10]. J Neurol Surg A Cent Eur Neurosurg. 2020;10.1055/s-0040-1710351. doi:10.1055/s-0040-1710351
5)

Kamel AAF, Amin OAI, Hassan MAMM, Elmesallamy WAEA, Hassan EM. Ultrasound prediction for vocal cord dysfunction in patients scheduled for anterior cervical spine surgeries: a prospective cohort study [published online ahead of print, 2020 Jun 15]. J Clin Monit Comput. 2020;10.1007/s10877-020-00546-3. doi:10.1007/s10877-020-00546-3
6)

Tasiou A, Giannis T, Brotis AG, Siasios I, Georgiadis I, Gatos H, Tsianaka E, Vagkopoulos K, Paterakis K, Fountas KN. Anterior cervical spine surgery-associated complications in a retrospective case-control study. J Spine Surg. 2017 Sep;3(3):444-459. doi: 10.21037/jss.2017.08.03. Review. PubMed PMID: 29057356; PubMed Central PMCID: PMC5637201.
7)

Staartjes VE, de Wispelaere MP, Schröder ML. Recurrent Laryngeal Nerve Palsy Is More Frequent After Secondary than After Primary Anterior Cervical Discectomy and Fusion: Insights from a Registry of 525 Patients. World Neurosurg. 2018 Aug;116:e1047-e1053. doi: 10.1016/j.wneu.2018.05.162. Epub 2018 Jun 1. PubMed PMID: 29864565

Iatrogenic peripheral nerve injury

Iatrogenic peripheral nerve injury

Treatment

Iatrogenic peripheral nerve injury is a considerable social and economic concern and the majority of cases are preventable. Complications should be referred to and dealt with promptly by experienced surgeons, to ensure the best chances for optimal functional recovery. Their prevention should be emphasized. Their management should include ensuring early diagnosis, administering an appropriate treatment with rehabilitation, rendering psychological support, and providing control of pain 1).

The combination of morphological assessment (neurosonography) with functional assessment (nerve conduction studies) is of paramount importance in the management of traumatic peripheral nerve injuries. If on sonography, the nerve appears intact, then intraoperative nerve conduction studies the functionality of the nerve. If conduction is impaired (signifying the presence of a neuroma-in-continuity), then nerve grafting is done. If the conduction is somewhat preserved, neurolysis is performed 2).

If it is noted during an operation that a nerve has been severed, it should be repaired immediately during the same operation (primary repair) or within 2–3 weeks (early secondary repair) 3).

The same is true when the nerve is torn or damaged but not cleanly cut. The same operative approach is used as for any other nerve injury. The repair ideally is done with microsurgical tools and magnifying devices, insuring maximal visualization for the repair.

Once again, this ideal situation with the immediate repair is seldom achieved. Usually, the cause of the damage is unknown. In our experience, the operative report rarely provides useful information. When the mechanism for the damage is unknown but there is reason to think that the nerve may regenerate itself, we prefer to wait 3 months with monthly neurological examinations. If at this time, the deficit has not changed or only minimally improved, the nerve should be surgically explored in the next month. If the neurosonographic examination after exposure of the nerve identifies a neuroma, one should not delay. The operation should ideally occur within 3 weeks 4).

A severed nerve should be reconstructed, if possible. Usually, this requires nerve grafting. The sural nerve on the lateral calf is usually used as a source. Other cutaneous nerves such as the saphenous nerve and the medial antebrachial cutaneous nerve can also be used 5). If the nerve appears to be intact, then intraoperative nerve conduction studies help assess how functional it is in the area of damage. If conductivity is impaired, then the affected segment of the nerve surrounded by scar tissue—usually thickened and diagnosed as a neuroma in continuity—is excised and replaced by a transplant. In other cases, when conductivity studies are more promising, it suffices to free the nerve up from the surrounding reactive tissues (neurolysis). In recent years intraoperative neuro sonography has been employed, facilitating the evaluation of individual nerve fascicles, helping distinguish between a complete neuroma in continuity without any residual fascicles and a partial lesion still containing functioning fascicles 6).

The combination of the functional evaluation (nerve conduction studies) and the morphologic assessment (neuro sonography) is very helpful in the surgical management of traumatic injuries in peripheral nerve surgery. The exact approach is documented in the interdisciplinary guidelines of the AWMF “Versorgung peripherer Nervenverletzungen” 7).

A key factor in improving the prognosis is physical therapy, both after the deficit is identified and then post-operatively until re-innervation of the affected muscles has occurred. Electric stimulation therapy is also worthwhile in our option. In this way, the muscle structures can be better maintained until nerve regeneration has occurred.

Case series

Dubuisson et al. analyzed the management of iatrogenic peripheral nerve injury (iNI) in 42 patients.

The iNI occurred mostly during a surgical procedure (n = 39), either on a nerve or plexus (n = 13), on bone, joint, vessel, or soft tissue (n = 24) or because of malpositioning (n = 2). The most commonly injured nerves were the brachial plexus, radial nerve, sciatic nerve, femoral nerve, or peroneal nerves. 42.9% of the patients were referred to later than 6 months. A neurological deficit was present in 37 patients and neuropathic pain in 17. Two patients were lost to follow-up. Conservative treatment was applied in 23 patients because of good spontaneous recovery or compensation or because of expected bad prognosis whatever the treatment. Surgical treatment was performed in 17 patients because of known nerve section (n = 2), persistent neurological deficit (n = 12) or invalidating neuropathic pain (n = 3); nerve reconstruction with grafts (n = 8) and neurolysis (n = 8) were the most common procedures. The outcome was satisfactory in 50%. Potential reasons for poor outcomes were a very proximal injury, placement of very long grafts, delayed referral, and predominance of neuropathic pain. According to the literature, delayed referral of iNI for treatment is frequent. They provides an illustrative case of a young girl operated on at 6.5 months for femoral nerve reconstruction with grafts while the nerve section was obvious from the operative note and pathological tissue analysis. Litigation claims (n = 10) resulted in malpractice (n = 2) or therapeutic area (n = 5) (3 unavailable conclusions).

NI can result in considerable disability, pain, and litigation. Optimal management is required 8).

Rasulić et al. describe and analyze iatrogenic nerve injuries in a total of 122 consecutive patients who received surgical treatment at there institution during a period of 10 years, from January 1, 2003, to December 31, 2013. The final outcome evaluation was performed 2 years after surgical treatment.

The most common causes of iatrogenic nerve injuries among patients in the study were the operations of bone fractures (23.9%), lymph node biopsy (19.7%), and carpal tunnel release (18%). The most affected nerves were median nerve (21.3%), accessory nerve (18%), radial nerve (15.6%), and peroneal nerve (11.5%). In 74 (60.7%) patients, surgery was performed 6 months after the injury, and in 48 (39.3%) surgery was performed within 6 months after the injury. In 80 (65.6%) patients, we found lesion in discontinuity, and in 42 (34.4%) patients lesion in continuity. The distribution of surgical procedures performed was as follows: autotransplantation (51.6%), neurolysis (23.8%), nerve transfer (13.9%), direct suture (8.2%), and resection of neuroma (2.5%). In total, we achieved satisfactory recovery in 91 (74.6%), whereas the result was dissatisfactory in 31 (25.4%) patients.

Patients with iatrogenic nerve injuries should be examined as soon as possible by experts with experience in traumatic nerve injuries so that the correct diagnosis can be reached and the appropriate therapy planned. The timing of reconstructive surgery and the technique used are the crucial factors for functional recover 9).

340 patients underwent surgery for iatrogenic nerve injuries over a 23-year period in the District Hospital of Günzburg (Neurosurgical Department of the University of Ulm). In a study published by the authors in 2001, 17.4% of the traumatic nerve lesions treated were iatrogenic. 94% of iatrogenic nerve injuries occurred during surgical procedures 10).

References

1)

Kumar A, Shukla D, Bhat DI, Devi BI. Iatrogenic peripheral nerve injuries. Neurol India. 2019;67(Supplement):S135-S139. doi:10.4103/0028-3886.250700
2)

Sinha S. Management protocol in the case of iatrogenic peripheral nerve injuries. Neurol India. 2019;67(Supplement):S140-S141. doi:10.4103/0028-3886.250696
3) , 4) , 5) , 7)

Deutsche Gesellschaft für Handchirurgie (DGH), Deutsche Gesellschaft für Neurologie (DGN), Deutsche Gesellschaft für Neurochirurgie (DGNC), Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie (DGOOC), Deutsche Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC), Deutsche Gesellschaft für Unfallchirurgie (DGU) Leitlinen: Versorgung peripherer Nervenverletzungen. http://www.awmf.org/leitlinien/detail/ll/005-010.html Stand 30.06.2013
6)

Koenig RW, Schmidt TE, Heinen CPG, et al. Intraoperative high-resolution ultrasound: a new technique in the management of peripheral nerve disorders. Clinical article Journal of Neurosurgery. 2011;114:514–521
8)

Dubuisson A, Kaschten B, Steinmetz M, et al. Iatrogenic nerve injuries: a potentially serious medical and medicolegal problem. About a series of 42 patients and review of the literature [published online ahead of print, 2020 Jul 11]. Acta Neurol Belg. 2020;10.1007/s13760-020-01424-0. doi:10.1007/s13760-020-01424-0
9)

Rasulić L, Savić A, Vitošević F, et al. Iatrogenic Peripheral Nerve Injuries-Surgical Treatment and Outcome: 10 Years’ Experience. World Neurosurg. 2017;103:841-851.e6. doi:10.1016/j.wneu.2017.04.099
10)

Antoniadis G, Kretschmer T, Pedro MT, König RW, Heinen CP, Richter HP. Iatrogenic nerve injuries: prevalence, diagnosis and treatment. Dtsch Arztebl Int. 2014;111(16):273-279. doi:10.3238/arztebl.2014.0273

Facial nerve schwannoma

Facial nerve schwannoma

Facial nerve schwannoma may arise in any portion of the facial nerve, with a predilection for the geniculate ganglion 1) 2).

They can occur anywhere from the internal auditory canal to the parotid gland. Schwannomas arising from the greater superficial petrosal nerve are exceedingly rare 3).

Clinical

Even in these tumors, hearing loss tends to precede facial paresis. Hearing loss may be sensorineural from VIII cranial nerve compression from tumors arising in the proximal portion of VII cranial nerve (cisternal or internal auditory canal (IAC) segment), or it may be conductive from erosion of the ossicles by tumors arising in the second (tympanic, or horizontal) segment of VII. Facial palsy (peripheral) may also develop, usually late 4).

Diagnosis

Computed tomography (CT) of the temporal bone is important for evaluating the impact on the surrounding structures 5).

Treatment

Treatment for intracranial facial nerve schwannomas depends on clinical presentation, tumor size, preoperative facial, and hearing function.

Conservative management is recommended for asymptomatic patients with small tumors. Stereotactic radiosurgery may be an option for smaller and symptomatic tumors with good facial function. If tumor is large or the patient has facial paralysis, surgical resection should be indicated. If preservation of the facial nerve is not possible, total resection with nerve grafting should be performed for those patients with facial paralysis, whereas subtotal resection is best for those patients with good facial function 6).

see Middle Fossa Approach for Facial Nerve Schwannoma.

These tumors must be assessed with imaging studies, incisional biopsy is not recommended. The treatment is surgical resection in symptomatic patients with facial paralysis greater than grade III of House-Brackmann, with immediate reconstruction of the nerve 7).

Case series

Facial nerve schwannoma case series.

Case reports

Facial nerve schwannoma case reports.

References

1) , 4)

Inoue Y, Tabuchi T, Hakuba A, et al. Facial Nerve Neuromas: CT Findings. J Comput Assist Tomogr. 1987; 11:942–947
2)

Tew JM, Yeh HS, Miller GW, Shahbabian S. Intratemporal Schwannoma of the Facial Nerve. Neurosurgery. 1983; 13:186–188
3)

Sade B, Lee JH. Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma. Case report. J Neurosurg. 2007 Jul;107(1):181-4. PubMed PMID: 17639892.
5)

Loos E, Wuyts L, Puls T, Foer B, Casselman JW, Bernaerts A, Vanspauwen R, Offeciers E, Dinther JV, Zarowski A, Somers T. Cochlear Erosion due to a Facial Nerve Schwannoma. J Int Adv Otol. 2019 Jul 9. doi: 10.5152/iao.2019.5304. [Epub ahead of print] PubMed PMID: 31287431.
6)

Xu F, Pan S, Alonso F, Dekker SE, Bambakidis NC. Intracranial Facial Nerve Schwannomas: Current Management and Review of Literature. World Neurosurg. 2017 Apr;100:444-449. doi: 10.1016/j.wneu.2016.09.082. Epub 2016 Sep 28. Review. PubMed PMID: 27693767.
7)

Prado-Calleros HM, Corvera-Behar G, García-de-la-Cruz M, Calderón-Wengerman Ó, Prado A, Pombo-Nava A. Tympanic-mastoid and parotid schwannomas of the facial nerve: clinical presentation related to the anatomic site of origin. Cir Cir. 2019;87(4):377-384. doi: 10.24875/CIRU.18000449. PubMed PMID: 31264987.

Vagal Nerve Schwannoma

Vagal Nerve Schwannoma

Epidemiology

Schwannoma arising from the vagus nerve is an uncommon (2–5%) benign nerve tumour.

Vagal Nerve Schwannomas are usually confined to the retrostyloid parapharyngeal space, although patients with schwannomas that extend into the posterior cranial fossa through the jugular foramen have been reported

Schwannomas arising from the vagus nerve are extremely rare in children, with only 16 cases reported in the world literature 1).

Clinical features

They usually presents as an asymptomatic slow growing mass 2).

Most cases of schwannomas manifest between the third and sixth decades of the patient’s life as a slow growing firm, painless mass in the lateral neck. Hoarseness, pain, or cough may be the presenting complaints. They displace the carotid arteries anteriorly and medially, jugular vein laterally and posteriorly. These swellings are mobile transversely but not vertically 3).

Diagnosis

Diagnosis is based on clinical suspicion and confirmation obtained by means of surgical pathology.

Differential diagnosis

Schwannomas of the vagus nerve must be differentiated from the carotid body and glomus vagale tumors because the distinction may influence treatment planning.

Treatment

Surgical excision is the treatment of choice for vagal schwannoma, with recurrence being rare.

Intermittent intraoperative neuromonitoring via selective stimulation of splayed motor fibers running on the schwannoma surface to elicit a compound muscle action potential has been previously reported as a method of preserving vagal motor fibers.

In a case report, vagal sensory fibers were mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes 4).

Outcome

Nerve damage during surgical resection is associated with significant morbidity 5).

This tumour most often presents as a slow growing asymptomatic solitary neck mass, which rarely undergoes malignant transformation.

Literature review

In a comprehensive literature review on 197 articles reporting 235 cases of cervical vagal schwannomas. Presenting symptoms, treatment approach, and postoperative outcomes were recorded and analyzed.

Vagal schwannomas commonly present as asymptomatic neck masses. When they become symptomatic, surgical resection is the standard of care. Gross total resection is associated with higher postoperative morbidity compared to subtotal resection. Initial reports using intraoperative nerve monitoring have shown improved nerve preservation. Recurrence rates are low.

The combination of intermittent nerve mapping with novel continuous vagal nerve monitoring techniques may reduce postoperative morbidity and could represent the future standard of care for vagal schwannoma treatment 6).

Case series

Case series of three patients who underwent vagal schwannoma excision utilizing a IONM technique. The recurrent laryngeal and vagus nerves were monitored via the laryngeal adductor reflex (LAR) using an electromyographic endotracheal tube.

Three patients with suspected vagal schwannomas were treated surgically using the intracapsular enucleation approach with a combination of intermittent IONM and continuous IONM of the LAR.

This combination of continuous and intermittent IONM can be used to preserve vagal laryngeal innervation and function and may represent the future standard of care for vagal schwannoma excision 7).

Green et al. reported 36 of these rare neoplasms in 35 patients. The majority of the tumors presented as a mass in the upper cervical or parapharyngeal region. Usually the mass was asymptomatic. The following types and frequencies of neoplasms of the vagus nerve were noted: paragangliomas, 50%; neurilemmomas, 31%; neurofibromas, 14%; and neurofibrosarcomas, 6%. Surgical resection, with preservation of the vagus nerve when possible, is the treatment of choice. The clinical features, diagnosis, management, and prognosis of the tumors are presented. Special problems that occur with vagal neoplasms include postoperative dysfunction, catecholamine secretion, and intracranial or skull-base extension 8).

Case reports

In a case report, vagal sensory fibers were mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes 9).

Keshelava et al. operated one patient for cervical schwannoma causing internal carotid artery (ICA) compression.

The patient underwent en bloc excision via transcervical approach under general anesthesia. Pathological examination demonstrated the diagnosis of schwannoma.

This case shows that VNS can cause ICA compression and therefore brain ischemia 10).

Schwam et al. reported a purely intracranial vagal schwannoma 11).

2018

A 60-year-old female patient was seen at our service for a slow-growing, 9 × 6 cm left-sided cystic neck mass. Preoperative clinical and computed tomography evaluation suggested a diagnosis of a lateral neck cyst. The surgical exploration through the lateral cervicotomy revealed a large cystic mass and clearly identified that the tumor was originating from the left vagal nerve. The histopathologic analysis confirmed the diagnosis of schwannoma. Although uncommon, vagal schwannoma with pronounced cystic component should be included in the differential diagnosis of the cystic neck swellings 12).

A 55-year-old woman who presented to the clinic complaining of throat irritation and feeling of something stuck in her throat for the past three months. On examination, a bulging left parapharyngeal mass was noted, displacing the left tonsil and uvula medially. A contrast-enhanced computed tomography (CT) scan of the neck showed a large, hypervascular soft tissue mass with splaying of the left internal carotid artery. Intraoperatively, the tumor was found to be arising from the vagus nerve. Macroscopic surgical pathology examination showed a tan-red, ovoid, and firm mass. Histopathology showed a benign spindle cell tumor with Antoni A areas with palisading cell nuclei and some degenerative change, confirming the diagnosis of vagus nerve schwannoma. CONCLUSIONS Vagus nerve schwannomas should be distinguished from other tumors that arise in the neck before planning surgery, to minimize the risk of nerve injury. Physicians need to be aware of the differential diagnosis of a neck mass, investigations required, the surgical treatment and the potential postoperative complications 13).

Sreevatsa et al. described three cases of schwannoma involving the vagus who presented differently to our unit during past 5 years 14).

A large vagal neurilemmoma in a 33-year-old man is reported. He complained of slowly progressive palsy of the tongue on the left side. Weakness of soft palate movement was also noted. Magnetic resonance imaging (MRI) revealed a tumour in the left parapharyngeal space with partial extension to the posterior cranial fossa through the jugular foramen. Carotid angiography revealed avascularity of the tumour and anterior shift of the left internal carotid artery. The venous phase showed no blood flow in the internal jugular vein. The tumour was successfully extirpated via a transmandibular transpterygoid approach. Although vagus nerve dysfunction was not observed pre-operatively, the tumour was identified as a neurilemmoma arising from the vagus nerve. The surgical approach should be selected according to the lesion in individual patients. Since neurilemmoma is benign in nature, minimal post-operative sequelae should be expected 15).

References

1)

Mierzwiński J, Wrukowska I, Tyra J, Paczkowski D, Szcześniak T, Haber K. Diagnosis and management of pediatric cervical vagal schwannoma. Int J Pediatr Otorhinolaryngol. 2018 Nov;114:9-14. doi: 10.1016/j.ijporl.2018.08.021. Epub 2018 Aug 23. PubMed PMID: 30262374.
2) , 13)

Ramdass AA, Yao M, Natarajan S, Bakshi PK. A Rare Case of Vagus Nerve Schwannoma Presenting as a Neck Mass. Am J Case Rep. 2017 Aug 21;18:908-911. PubMed PMID: 28824161; PubMed Central PMCID: PMC5574523.
3)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3227827/
4) , 9)

Sinclair CF, Téllez MJ, Sánchez Roldán MA, Urken M, Ulkatan S. Intraoperative mapping and monitoring of sensory vagal fibers during vagal schwannoma resection. Laryngoscope. 2019 Dec;129(12):E434-E436. doi: 10.1002/lary.28147. Epub 2019 Jun 18. PubMed PMID: 31211430.
5) , 7)

Sandler ML, Sims JR, Sinclair C, Ho R, Yue LE, Téllez MJ, Ulkatan S, Khorsandi AS, Brandwein-Weber M, Urken ML. A novel approach to neurologic function sparing surgical management of vagal schwannomas: Continuous intraoperative nerve monitoring of the laryngeal adductor reflex. Head Neck. 2019 Sep;41(9):E146-E152. doi: 10.1002/hed.25793. Epub 2019 May 6. PubMed PMID: 31058386.
6)

Sandler ML, Sims JR, Sinclair C, Sharif KF, Ho R, Yue LE, Téllez MJ, Ulkatan S, Khorsandi AS, Brandwein-Weber M, Urken ML. Vagal schwannomas of the head and neck: A comprehensive review and a novel approach to preserving vocal cord innervation and function. Head Neck. 2019 Jul;41(7):2450-2466. doi: 10.1002/hed.25758. Epub 2019 Apr 7. Review. PubMed PMID: 30957342.
8)

Green JD Jr, Olsen KD, DeSanto LW, Scheithauer BW. Neoplasms of the vagus nerve. Laryngoscope. 1988 Jun;98(6 Pt 1):648-54. PubMed PMID: 2836676.
10)

Keshelava G, Robakidze Z. Cervical Vagal Schwannoma Causing Asymptomatic Internal Carotid Artery Compression. Ann Vasc Surg. 2019 Oct 17. pii: S0890-5096(19)30859-3. doi: 10.1016/j.avsg.2019.09.021. [Epub ahead of print] PubMed PMID: 31629844.
11)

Schwam ZG, Kaul VZ, Shrivastava R, Wanna GB. Purely intracranial vagal schwannoma: A case report of a rare lesion. Am J Otolaryngol. 2019 May – Jun;40(3):443-444. doi: 10.1016/j.amjoto.2019.02.011. Epub 2019 Feb 18. PubMed PMID: 30799212.
12)

Cukic O, Jovanovic MB. Vagus Nerve Schwannoma Mimicking a Lateral Neck Cyst. J Craniofac Surg. 2018 Nov;29(8):e827-e828. doi: 10.1097/SCS.0000000000005006. PubMed PMID: 30320693.
14)

Sreevatsa MR, Srinivasarao RV. Three cases of vagal nerve schwannoma and review of literature. Indian J Otolaryngol Head Neck Surg. 2011 Oct;63(4):310-2. Epub 2011 Apr 8. PubMed PMID: 23024932; PubMed Central PMCID: PMC3227827.
15)

Yumoto E, Nakamura K, Mori T, Yanagihara N. Parapharyngeal vagal neurilemmoma extending to the jugular foramen. J Laryngol Otol. 1996 May;110(5):485-9. PubMed PMID: 8762326.

Vagus Nerve Stimulation outcome

Vagus Nerve Stimulation outcome

Evidence for long-term efficacy is still limited.

The true outcome of long-term VNS is difficult to assess in real-world practice. The effect may be overestimated due to confounding factors, particularly the common introduction of novel AEDs and the natural course of the disorder. Patients without perceived benefit from long-term VNS should not routinely remain on treatment and be subject to undue generator re-implantations 1).

Kawai et al. report the overall outcome of a national, prospective registry that included all patients implanted in Japan. The registry included patients of all ages with all seizure types who underwent VNS implantation for drug-resistant epilepsy in the first three years after approval of VNS in 2010. The registry excluded patients who were expected to benefit from resective surgery. Efficacy analysis was assessed based on the change in frequency of all seizure types and the rate of responders. Changes in cognitive, behavioural and social status, quality of life (QOL), antiepileptic drug (AED) use, and overall AED burden were analysed as other efficacy indices. A total of 385 patients were initially registered. Efficacy analyses included data from 362 patients. Age range at the time of VNS implantation was 12 months to 72 years; 21.5% of patients were under 12 years of age and 49.7% had prior epilepsy surgery. Follow-up rate was >90%, even at 36 months. Seizure control improved over time with median seizure reduction of 25.0%, 40.9%, 53.3%, 60.0%, and 66.2%, and responder rates of 38.9%, 46.8%, 55.8%, 57.7%, and 58.8% at three, six, 12, 24, and 36 months of VNS therapy, respectively. There were no substantial changes in other indices throughout the three years of the study, except for self/family-accessed QOL which improved over time. No new safety issues were identified. Although this was not a controlled comparative study, this prospective national registry of Japanese patients with drug-resistant epilepsy, with >90% follow-up rate, indicates long-term efficacy of VNS therapy which increased over time, over a period of up to three years. The limits of such trials, in terms of AED modifications and during follow-up and difficulties in seizure counting are also discussed 2).

VNS can affect the voice and reduced vocal cord motion on the implantation side with secondary supraglottic muscle tension. Otolaryngologists are not only capable of performing VNS implantation, but can also manage surgical complications, assess laryngeal side effects and treat them as needed 3).

VNS implantation may render patients with some forms of cortical dysgenesis (parietooccipital polymicrogyria, macrogyria) seizure-free. Patients with unilateral IEDs and earlier implantation achieved the most benefit from VNS 4).

References

1)

Brodtkorb E, Samsonsen C, Jørgensen JV, Helde G. Epilepsy patients with and without perceived benefit from vagus nerve stimulation: A long-term observational single center study. Seizure. 2019 Sep 19;72:28-32. doi: 10.1016/j.seizure.2019.09.004. [Epub ahead of print] PubMed PMID: 31563121.
2)

Kawai K, Tanaka T, Baba H, Bunker M, Ikeda A, Inoue Y, Kameyama S, Kaneko S, Kato A, Nozawa T, Maruoka E, Osawa M, Otsuki T, Tsuji S, Watanabe E, Yamamoto T. Outcome of vagus nerve stimulation for drug-resistant epilepsy: the first three years of a prospective Japanese registry. Epileptic Disord. 2017 Sep 1;19(3):327-338. doi: 10.1684/epd.2017.0929. PubMed PMID: 28832004.
3)

Al Omari AI, Alzoubi FQ, Alsalem MM, Aburahma SK, Mardini DT, Castellanos PF. The vagal nerve stimulation outcome, and laryngeal effect: Otolaryngologists roles and perspective. Am J Otolaryngol. 2017 Jul – Aug;38(4):408-413. doi: 10.1016/j.amjoto.2017.03.011. Epub 2017 Apr 4. PubMed PMID: 28390806.
4)

Ghaemi K, Elsharkawy AE, Schulz R, Hoppe M, Polster T, Pannek H, Ebner A. Vagus nerve stimulation: outcome and predictors of seizure freedom in long-term follow-up. Seizure. 2010 Jun;19(5):264-8. doi: 10.1016/j.seizure.2010.03.002. Epub 2010 Apr 1. PubMed PMID: 20362466.

Optic nerve sheath diameter ultrasonography

Optic nerve sheath diameter ultrasonography

Optic nerve sheath diameter ultrasonography is strongly correlated with invasive ICPmeasurements and may serve as a sensitive and noninvasive method for detecting elevated ICP in TBI patients after decompressive craniectomy 1).

Optic nerve sheath diameter measured by transorbital ultrasound imaging is an accurate method for detecting intracranial hypertension that can be applied in a broad range of settings. It has the advantages of being a non-invasive, bedside test, which can be repeated multiple times for re-evaluation 2).

Evolution of ultrasound technology and the development of high frequency (> 7.5 MHz) linear probes with improved spatial resolution have enabled excellent views of the optic nerve sheath.

The optic nerve sheath diameter (ONSD), measured at a fixed distance behind the retina has been evaluated to diagnose and measure intracranial hypertension in traumatic brain injury and intracranial hemorrhage 3) 4).

The optic nerve sheath is fairly easy to visualize by ultrasonography by insonation across the orbit in the axial plane. A-mode ultrasonography was used to view the optic nerve sheath more than four decades ago; B-mode scanning was performed subsequently to assess intraocular lesions 5).

Shirodkar et al., studied the efficacy of ONSD measurement by ultrasonography to predict intracranial hypertension. The case mix studied included meningoencephalitis, stroke, intracranial hemorrhage and metabolic encephalopathy. Using cut-off values of 4.6 mm for females, and 4.8 mm for males, they found a high level of sensitivity and specificity for the diagnosis of intracranial hypertension as evident on CT or MRI imaging 6).

There is wide variation reported in the optimal cut-off values, when ONSD was compared with invasive ICP monitoring, ranging from 4.8 to 5.9 mm7) 8).

Padayachy et al present a method for assessment of optic nerve sheath ONS pulsatile dynamics using transorbital ultrasound imaging. A significant difference was noted between the patient groups, indicating that deformability of the ONS may be relevant as a noninvasive marker of raised ICP 9).

Of the studied ultrasound noninvasive intracranial pressure monitoring, optic nerve sheath diameter (ONSD), is the best estimator of ICP. The novel combination of optic nerve sheath diameter ultrasonography and venous transcranial Doppler (vTCD) of the straight sinus is a promising and easily available technique for identifying critically ill patients with intracranial hypertension 10).

The optic nerve sheath diameter has been verified by various clinical studies as a non-invasive indicator of intracranial hypertension 11).

Correlations between ICP and Optic nerve sheath diameter (ONSD) using CT and MRI have been observed in adult populations.

Ultrasound methods has been proposed as an alternative safe technique for invasive ICP measuring methods 12).

Admission ONSD in decompressive craniectomy (DC) patients is high but does not predict mortality and unfavorable outcomes 13).

Intracranial pressure (ICP) can be noninvasively estimated from the sonographic measurement of the optic nerve sheath diameter (ONSD) and from the transcranial Doppler analysis of the pulsatility (ICPPI) and the diastolic component (ICPFVd) of the velocity waveform 14).

Where pediatric patients present with an ONSD of over 6.1mm following a TBI, ICP monitoring should be implemented 15).

Padayachy et al present a method for assessment of ONS pulsatile dynamics using transorbital ultrasound imaging. A significant difference was noted between the patient groups, indicating that deformability of the ONS may be relevant as a noninvasive marker of raised ICP 16).

While the ultrasonographic mean binocular ONSD (>4.53 mm) was completely accurate in detecting elevated ICP, color Doppler indices of the ophthalmic arteries were of limited value 17).

Bedside ultrasound may be useful in the diagnosis of midline intracranial shift by measurement of ONSD 18).

In patients with SAH and acute hydrocephalus after aneurysm rupture, the ONSD remains expanded after normalization of ICP. This is most likely due to an impaired retraction capability of the optic nerve sheath. This finding should be considered when using transorbital sonography in the neuromonitoring of aneurysmal SAH 19).

ONSD >5.5 mm yielded a sensitivity of 98.77% (95% CI: 93.3%-100%) and a specificity of 85.19% (95% CI: 66.3%-95.8%).In conclusion, the optimal cut-off point of ONSD for identifying IICP was 5.5 mm. ONSD seen on ocular US can be a feasible method for detection and serial monitoring of ICP in Korean adult patients 20).

Systematic review

The aim of a systematic review and meta-analysis will be to examine the accuracy of ONSD sonography for increased ICP diagnosis.

Koziarz et al. will include published and unpublished randomised controlled trials, observational studies, and abstracts, with no publication type or language restrictions. Search strategies will be designed to peruse the MEDLINE, Embase, Web of Science, WHO Clinical Trials, ClinicalTrials.gov, CINAHL, and the Cochrane Library databases. We will also implement strategies to search grey literature. Two reviewers will independently complete data abstraction and conduct quality assessment. Included studies will be assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. We will construct the hierarchical summary receiver operating characteristic curve for included studies and pool sensitivity and specificity using the bivariate model. We also plan to conduct prespecified subgroup analyses to explore heterogeneity. The overall quality of evidence will be rated using Grading of Recommendations, Assessment, Development and Evaluations (GRADE).

Research ethics board approval is not required for this study as it draws from published data and raises no concerns related to patient privacy. This review will provide a comprehensive assessment of the evidence on ONSD sonography diagnostic accuracy and is directed to a wide audience. Results from the review will be disseminated extensively through conferences and submitted to a peer-reviewed journal for publication 21).

Case series

Optic nerve sheath diameter ultrasonography case series.

References

1)

Wang J, Li K, Li H, Ji C, Wu Z, Chen H, Chen B. Ultrasonographic optic nerve sheath diameter correlation with ICP and accuracy as a tool for noninvasive surrogate ICP measurement in patients with decompressive craniotomy. J Neurosurg. 2019 Jul 19:1-7. doi: 10.3171/2019.4.JNS183297. [Epub ahead of print] PubMed PMID: 31323632.
2)

Beare NA, Kampondeni S, Glover SJ, Molyneux E, Taylor TE, Harding SP, Molyneux ME. Detection of raised intracranial pressure by ultrasound measurement of optic nerve sheath diameter in African children. Trop Med Int Health. 2008 Nov;13(11):1400-4. doi: 10.1111/j.1365-3156.2008.02153.x. Epub 2008 Oct 13. PubMed PMID: 18983275; PubMed Central PMCID: PMC3776606.
3)

Geeraerts T, Merceron S, Benhamou D, Vigué B, Duranteau J. Non-invasive assessment of intracranial pressure using ocular sonography in neurocritical care patients. Intensive Care Med. 2008;34:2062–7.
4)

Moretti R, Pizzi B. Optic nerve ultrasound for detection of intracranial hypertension in intracranial hemorrhage patients: Confirmation of previous findings in a different patient population. J Neurosurg Anesthesiol. 2009;21:16–20.
5)

Gangemi M, Cennamo G, Maiuri F, D’Andrea F. Echographic measurement of the optic nerve in patients with intracranial hypertension. Neurochirurgia (Stuttg) 1987;30:53–5.
6)

Shirodkar CG, Rao SM, Mutkule DP, Harde YR, Venkategowda PM, Mahesh MU. Optic nerve sheath diameter as a marker for evaluation and prognostication of intracranial pressure in Indian patients: An observational study. Ind J Crit Care Med. 2014;18:728–734
7)

Rajajee V, Vanaman M, Fletcher JJ, Jacobs TL. Optic nerve ultrasound for the detection of raised intracranial pressure. Neurocrit Care. 2011;15:506–15.
8)

Geeraerts T, Launey Y, Martin L, Pottecher J, Vigué B, Duranteau J, et al. Ultrasonography of the optic nerve sheath may be useful for detecting raised intracranial pressure after severe brain injury. Intensive Care Med. 2007;33:1704–11.
9) , 16)

Padayachy L, Brekken R, Fieggen G, Selbekk T. Pulsatile Dynamics of the Optic Nerve Sheath and Intracranial Pressure: An Exploratory In Vivo Investigation. Neurosurgery. 2016 Jul;79(1):100-7. doi: 10.1227/NEU.0000000000001200. PubMed PMID: 26813857; PubMed Central PMCID: PMC4900421.
10)

Robba C, Cardim D, Tajsic T, Pietersen J, Bulman M, Donnelly J, Lavinio A, Gupta A, Menon DK, Hutchinson PJA, Czosnyka M. Ultrasound non-invasive measurement of intracranial pressure in neurointensive care: A prospective observational study. PLoS Med. 2017 Jul 25;14(7):e1002356. doi: 10.1371/journal.pmed.1002356. eCollection 2017 Jul. PubMed PMID: 28742869.
11)

Choi SH, Min KT, Park EK, Kim MS, Jung JH, Kim H. Ultrasonography of the optic nerve sheath to assess intracranial pressure changes after ventriculo-peritoneal shunt surgery in children with hydrocephalus: a prospective observational study. Anaesthesia. 2015 Nov;70(11):1268-73. doi: 10.1111/anae.13180. Epub 2015 Aug 24. PubMed PMID: 26299256.
12)

Karami M, Shirazinejad S, Shaygannejad V, Shirazinejad Z. Transocular Doppler and optic nerve sheath diameter monitoring to detect intracranial hypertension. Adv Biomed Res. 2015 Oct 22;4:231. doi: 10.4103/2277-9175.167900. eCollection 2015. PubMed PMID: 26645016; PubMed Central PMCID: PMC4647120.
13)

Waqas M, Bakhshi SK, Shamim MS, Anwar S. Radiological prognostication in patients with head trauma requiring decompressive craniectomy: Analysis of optic nerve sheath diameter and Rotterdam CT Scoring System. J Neuroradiol. 2016 Feb;43(1):25-30. doi: 10.1016/j.neurad.2015.07.003. Epub 2015 Oct 20. PubMed PMID: 26492980.
14)

Robba C, Bragazzi NL, Bertuccio A, Cardim D, Donnelly J, Sekhon M, Lavinio A, Duane D, Burnstein R, Matta B, Bacigaluppi S, Lattuada M, Czosnyka M. Effects of Prone Position and Positive End-Expiratory Pressure on Noninvasive Estimators of ICP: A Pilot Study. J Neurosurg Anesthesiol. 2016 Mar 18. [Epub ahead of print] PubMed PMID: 26998650.
15)

Young AM, Guilfoyle MR, Donnelly J, Scoffings D, Fernandes H, Garnett MR, Agrawal S, Hutchinson PJ. Correlating optic nerve sheath diameter with opening intracranial pressure in pediatric traumatic brain injury. Pediatr Res. 2016 Aug 11. doi: 10.1038/pr.2016.165. [Epub ahead of print] PubMed PMID: 27513519.
17)

Tarzamni MK, Derakhshan B, Meshkini A, Merat H, Fouladi DF, Mostafazadeh S, Rezakhah A. The diagnostic performance of ultrasonographic optic nerve sheath diameter and color Doppler indices of the ophthalmic arteries in detecting elevated intracranial pressure. Clin Neurol Neurosurg. 2016 Feb;141:82-8. doi: 10.1016/j.clineuro.2015.12.007. Epub 2015 Dec 15. PubMed PMID: 26771156.
18)

Kazdal H, Kanat A, Findik H, Sen A, Ozdemir B, Batcik OE, Yavasi O, Inecikli MF. Transorbital Ultrasonographic Measurement of Optic Nerve Sheath Diameter for Intracranial Midline Shift in Patients with Head Trauma. World Neurosurg. 2016 Jan;85:292-7. doi: 10.1016/j.wneu.2015.10.015. Epub 2015 Oct 17. PubMed PMID: 26485420.
19)

Bäuerle J, Niesen WD, Egger K, Buttler KJ, Reinhard M. Enlarged Optic Nerve Sheath in Aneurysmal Subarachnoid Hemorrhage despite Normal Intracranial Pressure. J Neuroimaging. 2016 Mar-Apr;26(2):194-6. doi: 10.1111/jon.12287. Epub 2015 Aug 17. PubMed PMID: 26278326.
20)

Lee SU, Jeon JP, Lee H, Han JH, Seo M, Byoun HS, Cho WS, Ryu HG, Kang HS, Kim JE, Kim HC, Jang KS. Optic nerve sheath diameter threshold by ocular ultrasonography for detection of increased intracranial pressure in Korean adult patients with brain lesions. Medicine (Baltimore). 2016 Oct;95(41):e5061. PubMed PMID: 27741121; PubMed Central PMCID: PMC5072948.
21)

Koziarz A, Sne N, Kegel F, Alhazzani W, Nath S, Badhiwala JH, Rice T, Engels P, Samir F, Healey A, Kahnamoui K, Banfield L, Sharma S, Reddy K, Hawryluk GWJ, Kirkpatrick AW, Almenawer SA. Optic nerve sheath diameter sonography for the diagnosis of increased intracranial pressure: a systematic review and meta-analysis protocol. BMJ Open. 2017 Aug 11;7(8):e016194. doi: 10.1136/bmjopen-2017-016194. PubMed PMID: 28801417.

Oculomotor nerve palsy in chronic subdural hematoma

Oculomotor nerve palsy in chronic subdural hematoma

Isolated oculomotor nerve palsy is well known as a symptom of microvascular infarction and intracranial aneurysm, but unilateral oculomotor nerve palsy as an initial manifestation of chronic subdural hematoma (CSDH) is a rare clinical condition.

Oculomotor nerve palsy (ONP) usually occurs in chronic subdural hematoma (CSDH) as a common sign of brain herniation that typically is associated with a deterioration of consciousness.

Ninety-eight cases of cSDH were operated over a 6-year period, in which 14 cases were classified as being bilateral. Among these 14 cases, 6 cases showed a rapid and aggressive clinical course. Therefore, complicated risk factors, the initial data on coagulofibrinolytic examination, magnetic resonance imaging appearance, and prognosis were analyzed.

Of the 6 cases, 5 showed a rapid aggravation as they awaited surgery. The period of the aggravation since the initial diagnosis harboring cSDH was 19 to 54 hours. One case was at first neurologically free from any disturbance but 17 hours later experienced a generalized seizure. All 6 cases experienced consciousness disturbance. In addition, 3 of them manifested oculomotor palsy 1).

Case reports

Zavatto et al., reported a bilateral oculomotor palsy after surgical evacuation of chronic subdural hematoma 2).

Corrivetti et al., reported 2 cases of bilateral CSDH who presented with ONP without deterioration of consciousness. An extensive literature reviewrevealed this is an extremely rare finding.

They also investigated all the possible pathogenic mechanisms producing nerve impairment and found a strong association with bilateral subdural hematoma. Vascular compression between posterior circulation arteries and tentorial edge abnormalities also could be involved. Vulnerability of the oculomotor nerve seems to be a necessary condition leading to clinical onset and is caused by predisposing factors to nerve damage, including vascular disease, head trauma, or herpes zoster infection.

Although isolated ONP is a very rare presentation of CSDH, a differential diagnosis is absolutely necessary, because surgical treatment allows good recovery of third nerve palsy in most of the cases 3).

Matsuda et al., reported a rare case of an 84-year-old woman with bilateral CSDH who presented with unilateral oculomotor nerve palsy as the initial symptom. The patient, who had a medical history of minor head injury 3 weeks prior, presented with left ptosis, diplopia, and vomiting. She had taken an antiplatelet drug for lacunar cerebral infarction. Computed tomography (CT) of the head showed bilateral CSDH with a slight midline shift to the left side. She underwent an urgent evacuation through bilateral frontal burr holes. Magnetic resonance angiography (MRA) after evacuation revealed no intracranial aneurysms, but constructive interference in steady-state (CISS) magnetic resonance imaging (MRI) revealed that the left posterior cerebral artery (PCA) ran much more anteriorly and inferiorly compared with the right PCA and the left oculomotor nerve passed very closely between the left PCA and the left superior cerebellar artery (SCA). There is the possibility that the strong compression to the left uncus, the left PCA, and the left SCA due to the bilateral CSDH resulted in left oculomotor nerve palsy with an initial manifestation without unconsciousness. Unilateral oculomotor nerve palsy as an initial presentation caused by bilateral CSDH without unconsciousness is a rare clinical condition, but this situation is very important as a differential diagnosis of unilateral oculomotor nerve palsy 4).

Jalil et al., reported the case of a patient who presented with left oculomotor cranial nerve palsy with an associated large volume left acute on chronic subdural haematoma. Coincidentally, this woman was also found to have a recent history of herpes zoster ophthalmicus 5).

Moon et al., reported two cases of Kernohan’s notch phenomenon secondary to chronic subdural hematoma detected by MRI. In the first case, the patient was drowsy with an oculomotor palsy and a hemiparesis ipsilateral to the chronic subdural hematoma. MRI in the post-operative period showed no abnormal signal or deformity of the crus cerebri. The neurological signs immediately resolved after trephination. In the second case, the patient was admitted with progressive decrease in their level of consciousness and ipsilateral hemiparesis with the chronic subdural hematoma. MRI on admission revealed an abnormal signal in the contralateral crus cerebri against the chronic subdural hematoma. After surgery, the mental state gradually recovered to normal with some degree of residual hemiparesis. In patients with chronic subdural hematoma, a compressive deformity of the crus cerebri, without abnormal signal on MRI, may predict a better neurological recovery in patients with Kernohan’s notch phenomenon 6).

Mishra et al., reported a 50-year old male patient with complaints of drooping of the right upper eyelid, for the past 1 day. He also gave a history of generalized mild headache for the past 1 week. There was no history of any injury, vomiting, fever, seizures, loss of consciousness, slurred speech, numbness, weakness, diplopia or any other major systemic illnesses like hypertension or diabetes. The patient also gave no history of any cardiovascular disorder. Patient was not a known alcoholic and neither was he on any anti coagulant or anti platelet therapy. On examination the patient was conscious and well oriented in time and space. His vitals were all within normal limits. Neurological examination was strictly unremarkable. Blood test revealed a normal blood count, urea, creatinine and electrolytes and was also negative for HIV antibodies. Ocular examination of the right eye revealed a vision of 6/9, improving to 6/6 with pin hole. There was severe ptosis with the marginal reflex distance 1 (MRD1) < −0.5 mm and a poor levator function (<4 mm). The eyeball too was displaced outwards and downwards (infraducted and abducted). The ocular movements were severely affected, with an absence of adduction and elevation; however abduction was full with mild residual depression. Depression was accompanied by intorsion, maximally when the eye was abducted. The pupil was dilated (6 mm) and un-reactive to light (vs. 3 mm and reactive in the left eye). Fundus was essentially normal. The left eye was uninvolved. A provisional diagnosis of isolated unilateral oculomotor nerve palsy, right eye, was made and the suspected site of involvement of the nerve was clinically deduced to be around the fascicular subarachnoid portion. This is because the fascicles of the third cranial nerve exit the mid brain through the medial aspect of the cerebral peduncles and are not near any other cranial nerves at this point. So isolated third cranial nerve palsy occurs from lesions in this location. Aneurysm is the most common lesion to affect the third cranial nerve in the subarachnoid space. The fact that the pupil too was involved pointed towards a posterior communicating artery aneurysm. A provisional diagnosis of a posterior communicating artery aneurysm with or without overt subarachnoid haemorrhage was made and the patient was sent for an urgent computed tomography (CT scan) of the brain and orbits, which revealed a CSDH in the right fronto-temporo-parietal lobe, causing mass effect in the form of compression of the right lateral ventricle and a midline shift of 16.5 mm. The patient was immediately transferred to a higher neurological centre where he underwent evacuation of the haematoma via a right frontal burr hole surgery. Post operative period was uneventful and the patient was put on anti epileptics (tablet dilantin 300 mg once daily), observed for 2 months and then sent on 04 weeks sick leave. His oculomotor nerve palsy gradually recovered completely and CT scan brain repeated on his return from sick leave showed a complete resolution of the haematoma. He was finally discharged back to his unit with no residual adverse effects whatsoever 7).

Cortes-Franco et al.,published in 2006 a Isolated IIIrd nerve palsy as the only sign of chronic subdural haematoma 8).

Ortega-Martínez et al., reported a patient with a chronic subdural hematoma that presented with a complete third nerve palsy and normal consciousness. Complete recovery was achieved after surgical evacuation. Rebleeding within the hematoma cavity, most possibly favored by antiaggregating agents, was considered responsible for this rare presentation. In these cases expeditious surgical evacuation is indicated 9).

A case of a 41-year-old man with a 1-month history of postural headache due to spontaneous intracranial hypotension (SIH). His MRI revealed bilateral chronic subdural hematoma (CSH) and diffuse dural enhancement after gadolinium infusion. Indium-111 radionuclide cisternography revealed a CSF leak from the cervico-thoracic junction and rapid accumulation of radioisotope in the bladder. Postural headache failed to resolve with prolonged bed rest. The patient became restless and suffered recent memory disturbance. We therefore decided to treat the CSF leak with an epidural blood patch. After the procedure, the patient’s headache resolved completely. However one day later, left oculomotor nerve palsy developed. MRI revealed enlargement of the left CSH with mass effect and midline shift. After hematoma drainage, the patient became alert and oculomotor palsy recovered gradually. To treat cases of CSH with SIH, the best method is to repair the CSF leakage and treat subdural hematoma at the same time. If the patient shows depressed consciousness, we recommend initial drainage of the subdural hematoma, because, following the repair of CSF leakage, mass effect such as uncal herniation may occur 10).

An 85-year-old male presented with bilateral chronic subdural hematomas (CSDHs) resulting in unilateral oculomotor nerve paresis and brainstem symptoms immediately after removal of both hematomas in a single operation. Initial computed tomography on admission demonstrated marked thick bilateral hematomas buckling the brain parenchyma with a minimal midline shift. Almost simultaneous removal of the hematomas was performed with the left side was decompressed first with a time difference of at most 2 minutes. However, the patient developed right oculomotor nerve paresis, left hemiparesis, and consciousness disturbance after the operation. The relatively marked increase in pressure on the right side may have caused transient unilateral brain stem compression and herniation of unilateral medial temporal lobe during the short time between the right and left procedures. Another factor was the vulnerability of the oculomotor nerve resulting from posterior replacement of the brain stem and stretching of the oculomotor nerves as seen on sagittal magnetic resonance (MR) images. Axial MR images obtained at the same time demonstrated medial deflection of the distal oculomotor nerve after crossing the posterior cerebral artery, which indicates previous transient compression of the nerve and the brain stem. Gradual and symmetrical decompression without time lag is recommended for the treatment of huge bilateral CSDHs 11).

In 1994 Phookan and Cameron published a bilateral chronic subdural haematoma with isolated oculomotor nerve palsy 12).

Crone et al published in 1985 a patient with adult-onset diabetes mellitus who developed an oculomotor palsy with pupillary sparing. Five days after her initial evaluation, she presented in a confused state with a complete oculomotor palsy. Computed cranial tomography revealed a chronic subdural hematoma. They recommend that noninvasive radiographic intracranial investigation be considered in elderly patients with adult-onset diabetes mellitus who present with headache and pupil-sparing oculomotor palsy 13).

References

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Kurokawa Y, Ishizaki E, Inaba K. Bilateral chronic subdural hematoma cases showing rapid and progressive aggravation. Surg Neurol. 2005 Nov;64(5):444-9; discussion 449. PubMed PMID: 16253697.
2)

Zavatto L, Marrone F, Allevi M, Ricci A, Taddei G. Bilateral oculomotor palsy after surgical evacuation of chronic subdural hematoma. World Neurosurg. 2019 Apr 10. pii: S1878-8750(19)31035-6. doi: 10.1016/j.wneu.2019.04.043. [Epub ahead of print] PubMed PMID: 30980981.
3)

Corrivetti F, Moschettoni L, Lunardi P. Isolated Oculomotor Nerve Palsy as Presenting Symptom of Bilateral Chronic Subdural Hematomas: Two Consecutive Case Report and Review of the Literature. World Neurosurg. 2016 Apr;88:686.e9-12. doi: 10.1016/j.wneu.2015.11.012. Epub 2015 Nov 14. Review. PubMed PMID: 26585722.
4)

Matsuda R, Hironaka Y, Kawai H, Park YS, Taoka T, Nakase H. Unilateral oculomotor nerve palsy as an initial presentation of bilateral chronic subdural hematoma: case report. Neurol Med Chir (Tokyo). 2013;53(9):616-9. PubMed PMID: 24067774; PubMed Central PMCID: PMC4508681.
5)

Jalil MF, Tee JW, Han T. Isolated III cranial nerve palsy: a surprising presentation of an acute on chronic subdural haematoma. BMJ Case Rep. 2013 Jun 19;2013. pii: bcr2013009992. doi: 10.1136/bcr-2013-009992. PubMed PMID: 23784767; PubMed Central PMCID: PMC3702887.
6)

Moon KS, Lee JK, Joo SP, Kim TS, Jung S, Kim JH, Kim SH, Kang SS. Kernohan’s notch phenomenon in chronic subdural hematoma: MRI findings. J Clin Neurosci. 2007 Oct;14(10):989-92. PubMed PMID: 17823049.
7)

Mishra A, Shukla S, Baranwal VK, Patra VK, Chaudhary B. Isolated unilateral IIIrd nerve palsy as the only sign of chronic subdural haematoma. Med J Armed Forces India. 2015 Jul;71(Suppl 1):S127-30. doi: 10.1016/j.mjafi.2013.07.009. Epub 2013 Sep 26. PubMed PMID: 26265807; PubMed Central PMCID: PMC4529560.
8)

Cortes-Franco S, García-Marín VM, Pacheco-Abreu EM, Roldán Delgado H. [Isolated IIIrd nerve palsy as the only sign of chronic subdural haematoma]. Med Clin (Barc). 2006 Sep 30;127(12):479. Spanish. PubMed PMID: 17040640.
9)

Ortega-Martínez M, Fernández-Portales I, Cabezudo JM, Rodríguez-Sánchez JA, Gómez-Perals LF, Giménez-Pando J. [Isolated oculomotor palsy. An unusual presentation of chronic subural hematoma]. Neurocirugia (Astur). 2003 Oct;14(5):423-5; discussion 425. Spanish. PubMed PMID: 14603390.
10)

Mikawa S, Ebina T. [Spontaneous intracranial hypotension complicating subdural hematoma: unilateral oculomotor nerve palsy caused by epidural blood patch]. No Shinkei Geka. 2001 Aug;29(8):747-53. Review. Japanese. PubMed PMID: 11554093.
11)

Okuchi K, Fujioka M, Maeda Y, Kagoshima T, Sakaki T. Bilateral chronic subdural hematomas resulting in unilateral oculomotor nerve paresis and brain stem symptoms after operation–case report. Neurol Med Chir (Tokyo). 1999 May;39(5):367-71. PubMed PMID: 10481440.
12)

Phookan G, Cameron M. Bilateral chronic subdural haematoma: an unusual presentation with isolated oculomotor nerve palsy. J Neurol Neurosurg Psychiatry. 1994 Sep;57(9):1146. PubMed PMID: 8089699; PubMed Central PMCID: PMC1073157.
13)

Crone KR, Lee KS, Davis CH Jr. Oculomotor palsy with pupillary sparing in a patient with chronic subdural hematoma. Surg Neurol. 1985 Dec;24(6):668-70. PubMed PMID: 4060048.

Cranial nerve tractography

Cranial nerve tractography

Diffusion imaging tractography caught the attention of the scientific community by describing the white matter architecture in vivo and noninvasively, but its application to small structures such as cranial nerves remains difficult. The few attempts to track cranial nerves presented highly variable acquisition and tracking settings.

A “targeted” review of the scientific literaturewas carried out using the MEDLINEdatabase.

Jacquesson et al., selected studies that reported how to perform the tractography of cranial nerves, and extracted the following: clinical context; imaging acquisition settings; tractography parameters; regions of interest (ROIs) design; and filtering methods.

Twenty-one published articles were included. These studied the optic nerves in suprasellar tumors, the trigeminal nerve in neurovascular conflicts, the facial nerve position around vestibular schwannomas, or all cranial nerves. Over time, the number of MRI diffusion gradient directions increased from 6 to 101. Nine tracking software packages were used which offered various types of tridimensional display. Tracking parameters were disparately detailed except for fractional anisotropy, which ranged from 0.06 to 0.5, and curvature angle, which was set between 20° and 90°. ROI design has evolved towards a multi-ROI strategy. Furthermore, new algorithms are being developed to avoid spurious tracts and improve angular resolution.

This review highlights the variability in the settings used for cranial nerve tractography. It points out challenges that originate both from cranial nerve anatomy and the tractography technology, and allows a better understanding of cranial nerve tractography 1).

Case series

Five neurologically healthy adults and 3 patients with brain tumors were scanned with diffusion spectrum imaging that allowed high-angular-resolution fiber tracking. In addition, a 488-subject diffusion magnetic resonance imaging template constructed from the Human Connectome Project data was used to conduct atlas space fiber tracking of CNs.

The cisternal portions of most CNs were tracked and visualized in each healthy subject and in atlas fiber tracking. The entire optic radiation, medial longitudinal fasciculus, spinal trigeminal nucleus/tract, petroclival portion of the abducens nerve, and intrabrainstem portion of the facial nerve from the root exit zone to the adjacent abducens nucleus were identified. This suggested that the high-angular-resolution fiber tracking was able to distinguish the facial nerve from the vestibulocochlear nerve complex. The tractography clearly visualized CNs displaced by brain tumors. These tractography findings were confirmed intraoperatively.

Using high-angular-resolution fiber tracking and atlas-based fiber tracking, we were able to identify all CNs in unprecedented detail. This implies its potential in localization of CNs during surgical planning 2).

Videos

Visualization of Cranial Nerves Using High-Definition Fiber Tractography

References

1)

Jacquesson T, Frindel C, Kocevar G, Berhouma M, Jouanneau E, Attyé A, Cotton F. Overcoming Challenges of Cranial Nerve Tractography: A Targeted Review. Neurosurgery. 2019 Feb 1;84(2):313-325. doi: 10.1093/neuros/nyy229. PubMed PMID: 30010992.
2)

Yoshino M, Abhinav K, Yeh FC, Panesar S, Fernandes D, Pathak S, Gardner PA, Fernandez-Miranda JC. Visualization of Cranial Nerves Using High-Definition Fiber Tractography. Neurosurgery. 2016 Jul;79(1):146-65. doi: 10.1227/NEU.0000000000001241. PubMed PMID: 27070917.