Robotic pedicle screw placement

Robotic pedicle screw placement

Robotic spinal fixation is associated with increased screw placement accuracy and similar operative blood loss, length of stay, and operative duration. These findings support the safety and cost-effectiveness of robotic spinal surgery across the spectrum of robotic systems and screw types 1).


In addition to demonstrating excellent pedicle screw accuracy, early studies have explored the impact of robot-assisted spine surgery on reducing radiation time, length of hospital stay, operative time, and perioperative complications in comparison to conventional freehand technique. The Mazor X Stealth Edition was introduced in 2018. This robotic system integrates Medtronic’s Stealth navigation technology into the Mazor X platform, which was introduced in 2016. It is unclear what the impact of these advancements have made on clinical outcomes.


In a multicenter study, both robot systems achieved excellent screw accuracy and low robot time per screw. However, using Stealth led to significantly less fluoroscopic radiation time, lower robot abandonment rates, and reduced blood transfusion rates than Mazor X. Other factors including length of stay, and 90-day complications were similar 2)

Ha Y. Robot-Assisted Spine Surgery: A Solution for Aging Spine Surgeons. Neurospine. 2018 Sep;15(3):187-188. doi: 10.14245/ns.18edi.003. Epub 2018 Sep 11. PubMed PMID: 30196675.


In three cadavers 12 pedicle screws were implanted in thoraco-lumbar segments with the robotic surgery assistant. 3D-fluoroscopy was performed for preoperative referencing, planning and identification of postoperative screw position. The radiation exposure of fluoroscopy and a CT scanner was compared, measuring the Computed Tomography Dose Index (CTDIw ).

Pedicle screw positioning was graded according to the Gertzbein-Robbins classification: Eleven of 12 pedicle screws showed optimal transpedicular position (Grade 1), one was positioned less than 2 mm outside (Grade 2). No major deviations were observed. Referencing with 3D-fluoroscopy resulted in a CTDIw reduction of 84% in the cervical- and 33% in the lumbar spine.

Robot-guided PS placement, using 3D-fluoroscopy for referencing, is a reliable tool for minimally invasive PS implantation; radiation exposure can be reduced 3).


Menger et al., investigated the cost effectiveness of adding robotic technology in spine surgery to an active neurosurgical practice.

The time of operative procedures, infection rates, revision rates, length of stay, and possible conversion of open to minimally invasive spine surgery (MIS) secondary to robotic image guidance technology were calculated using a combination of institution-specific and national data points. This cost matrix was subsequently applied to 1 year of elective clinical case volume at an academic practice with regard to payor mix, procedural mix, and procedural revenue.

A total of 1,985 elective cases were analyzed over a 1-year period; of these, 557 thoracolumbar cases (28%) were analyzed. Fifty-eight (10.4%) were MIS fusions. Independent review determined an additional ~10% cases (50) to be candidates for MIS fusion. Furthermore, 41.4% patients had governmental insurance, while 58.6% had commercial insurance. The weighted average diagnosis-related group reimbursement for thoracolumbar procedures for the hospital system was calculated to be $25,057 for Medicare and $42,096 for commercial insurance. Time savings averaged 3.4 minutes per 1-level MIS procedure with robotic technology, resulting in annual savings of $5,713. Improved pedicle screw accuracy secondary to robotic technology would have resulted in 9.47 revisions being avoided, with cost savings of $314,661. Under appropriate payor mix components, robotic technology would have converted 31 Medicare and 18 commercial patients from open to MIS. This would have resulted in 140 fewer total hospital admission days ($251,860) and avoided 2.3 infections ($36,312). Robotic surgery resulted in immediate conservative savings estimate of $608,546 during a 1-year period at an academic center performing 557 elective thoracolumbar instrumentation cases.

Application of robotic spine surgery is cost-effective, resulting in lesser revision surgery, lower infection rates, reduced length of stay, and shorter operative time. Further research is warranted, evaluating the financial impact of robotic spine surgery 4).


Several randomized controlled trials (RCTs) and cohort studies involving robotic-assisted (RA) and free-hand with fluoroscopy-guided (FH) and published before January 2017 were searched for using the Cochrane LibraryOvidWeb of SciencePubMed, and EMBASE databases. A total of 55 papers were selected. After the full-text assessment, 45 clinical trials were excluded. The final meta-analysis included 10 articles.

The accuracy of pedicle screw placement within the RA group was significantly greater than the accuracy within the FH group (odds ratio 95%, “perfect accuracy” confidence interval: 1.38-2.07, P < .01; odds ratio 95% “clinically acceptable” Confidence Interval: 1.17-2.08, P < .01).

There are significant differences in accuracy between RA surgery and FH surgery. It was demonstrated that the RA technique is superior to the conventional method in terms of the accuracy of pedicle screw placement 5).


In 2013 a study evaluated the outcomes of robotic-assisted screw placement in a consecutive series of 102 patients.

Data were recorded from technical notes and operative records created immediately following each surgery case, in which the robotic system was used to guide pedicle screw placement. All cases were performed at the same hospital by a single surgeon. The majority of patients had spinal deformity and/or previous spine surgery. Each planned screw placement was classified as: (1) successful/accurately placed screw using robotic guidance; (2) screw malpositioned using robot; (3) use of robot aborted and screw placed manually; (4) planned screw not placed as screw deemed non essential for construct stability. Data from each case were reviewed by two independent researchers to indentify the diagnosis, number of attempted robotic guided screw placements and the outcome of the attempted placement as well as complications or reasons for non-placement.

Robotic-guided screw placement was successfully used in 95 out of 102 patients. In those 95 patients, 949 screws (87.5 % of 1,085 planned screws) were successfully implanted. Eleven screws (1.0 %) placed using the robotic system were misplaced (all presumably due to “skiving” of the drill bit or trocar off the side of the facet). Robotic guidance was aborted and 110 screws (10.1 %) were manually placed, generally due to poor registration and/or technical trajectory issues. Fifteen screws (1.4 %) were not placed after intraoperative determination that the screw was not essential for construct stability. The robot was not used as planned in seven patients, one due to severe deformity, one due to very high body mass index, one due to extremely poor bone quality, one due to registration difficulty caused by previously placed loosened hardware, one due to difficulty with platform mounting and two due to device technical issues.

Of the 960 screws that were implanted using the robot, 949 (98.9 %) were successfully and accurately implanted and 11 (1.1 %) were malpositioned, despite the fact that the majority of patients had significant spinal deformities and/or previous spine surgeries. “Tool skiving” was thought to be the inciting issue with the misplaced screws. Intraoperative anteroposterior and oblique fluoroscopic imaging for registration is critical and was the limiting issue in four of the seven aborted cases 6).

Robotic pedicle screw placement learning curve.


1)

Himstead AS, Shahrestani S, Brown NJ, Produturi G, Shlobin NA, Al Jammal O, Choi EH, Ransom SC, Daniel Diaz-Aguilar L, Sahyouni R, Abraham M, Pham MH. Bony fixation in the era of spinal robotics: A systematic review and meta-analysis. J Clin Neurosci. 2022 Jan 19;97:62-74. doi: 10.1016/j.jocn.2022.01.005. Epub ahead of print. PMID: 35065405.
2)

Lee NJ, Zuckerman SL, Buchanan IA, Boddapati V, Mathew J, Leung E, Park PJ, Pham MH, Buchholz AL, Khan A, Pollina J, Mullin JP, Jazini E, Haines C, Schuler TC, Good CR, Lombardi JM, Lehman RA. Is There a Difference Between Navigated and Non-Navigated Robot Cohorts in Robot-Assisted Spine Surgery? A Multicenter, Propensity-Matched Analysis of 2,800 Screws and 372 Patients. Spine J. 2021 May 19:S1529-9430(21)00253-9. doi: 10.1016/j.spinee.2021.05.015. Epub ahead of print. PMID: 34022461.
3)

Spyrantis A, Cattani A, Seifert V, Freiman TM, Setzer M. Minimally invasive percutaneous robotic thoracolumbar pedicle screw implantation combined with three-dimensional-fluoroscopy can reduce radiation: a cadaver and phantom study. Int J Med Robot. 2019 Jun 19:e2022. doi: 10.1002/rcs.2022. [Epub ahead of print] PubMed PMID: 31216120.
4)

Menger RP, Savardekar AR, Farokhi F, Sin A. A Cost-Effectiveness Analysis of the Integration of Robotic Spine Technology in Spine Surgery. Neurospine. 2018 Aug 29. doi: 10.14245/ns.1836082.041. [Epub ahead of print] PubMed PMID: 30157583.
5)

Fan Y, Du JP, Liu JJ, Zhang JN, Qiao HH, Liu SC, Hao DJ. Accuracy of pedicle screw placement comparing robot-assisted technology and the free-hand with fluoroscopy-guided method in spine surgery: An updated meta-analysis. Medicine (Baltimore). 2018 Jun;97(22):e10970. doi: 10.1097/MD.0000000000010970. Review. PubMed PMID: 29851848; PubMed Central PMCID: PMC6392558.
6)

Hu X, Ohnmeiss DD, Lieberman IH. Robotic-assisted pedicle screw placement: lessons learned from the first 102 patients. Eur Spine J. 2013 Mar;22(3):661-6. doi: 10.1007/s00586-012-2499-1. Epub 2012 Sep 14. PubMed PMID: 22975723; PubMed Central PMCID: PMC3585630.

Acute ischemic stroke treatment

Acute ischemic stroke treatment

As the second-leading cause of death, stroke faces several challenges in terms of treatment because of the limited therapeutic interventions available. Previous studies primarily focused on metabolic and blood flow properties as a target for ischemic stroke treatment, including recombinant tissue plasminogen activator and mechanical thrombectomy, which are the only USFDA approved therapies. These interventions have the limitation of a narrow therapeutic time window, the possibility of hemorrhagic complications, and the expertise required for performing these interventions. Thus, it is important to identify the contributing factors that exacerbate the acute ischemic stroke outcome and to develop therapies targeting them for regulating cellular homeostasis, mainly neuronal survival and regeneration. Glial cells, primarily microgliaastrocytes, and oligodendrocytes, have been shown to have a crucial role in the prognosis of ischemic brain injury, contributing to inflammatory responses. They play a dual role in both the onset as well as resolution of the inflammatory responses. Understanding the different mechanisms driving these effects can aid in the development of therapeutic targets and further mitigate the damage caused. In a review, Jadhav et al. summarize the functions of various glial cells and their contribution to stroke pathology. The review highlights the therapeutic options currently being explored and developed that primarily target glial cells and can be used as neuroprotective agents for the treatment of ischemic stroke 1).


In the complete absence of blood flowneuronal death occurs within 2–3 minutes from the exhaustion of energy stores. However, in most strokes, there is a salvageable penumbra (tissue at risk) that retains viability for a period of time through suboptimal perfusion from collaterals. Local cerebral edema from the stroke results in a compromise of these collaterals and progression of the ischemic penumbra to infarction if the flow is not restored and maintained. Prevention of this secondary neuronal injury drives the treatment of stroke and has led to the creation of designated Primary Stroke Centers that offer appropriate and timely triage and treatment of all potential stroke patients.

Time delays from initial CTA acquisition to neuroendovascular surgery (NES) team notification can prevent expedient treatment with endovascular thrombectomy (ET). Process improvements and automated stroke detection on imaging with automated notification of the NES team may ultimately improve the time to reperfusion 2).

Restoring the circulation is the primary goal in emergency cerebral ischemia treatment. However, better understanding of how the brain responds to energy depletion could inform the time available for resuscitation until irreversible damage and advance development of interventions that prolong this span.


Finding novel agent for cerebral ischemia therapy is urgently required. In a study, Gao et al., aimed to investigate the regulatory mechanism of Ginkgolides B (GB) in hypoxia-injured PC-12 cells.

PC-12 cells were exposed to hypoxia and administrated with GB. Cell viability was detected by MTT assay. Flow cytometry assay was conducted for the detection of cell apoptosis, ROS generation and cell cycle assay. The changes of protein levels of Bax, Pro/Cleaved-Caspase-3, CyclinD1, CDK4, CDK6, PI3K/AKT and MEK/ERK pathways were detected by Western blot. Transfection was conducted for Polo-like kinase 1 (PLK1) knockdown.

Hypoxia-induced decrease of cell viability and increase of ROS generation, apoptosis and cell cycle arrest were ameliorated by GB. Hypoxia disposition hindered PI3 K/AKT and MEK/ERK signaling pathways while GB had the opposite effects. Then we observed that hypoxia exposure suppressed PLK1 expression while GB increased PLK1 expression dose-dependently. Knockdown of PLK1 attenuated the neuroprotective effects of GB on hypoxia-injured PC-12 cells and also inhibited PI3 K/AKT and MEK/ERK pathways.

The above observations corroborated that GB alleviated hypoxia-induced PC-12 cell injury by up-regulation of PLK1 via activating PI3K/AKT and MEK/ERK pathways. These findings implied the neuro-protective impacts in hypoxia-injured PC-12 cells 3).

see also Cerebral venous sinus thrombosis treatment.


Remarkable developments in the field of endovascular neurosurgery have been witnessed in the last decade. The success of endovascular therapy for ischemic stroke treatment is now irrefutable, making it an accepted standard of care 4).

In ischemic stroke or patients with TIA less than five cerebral microbleeds (CMBs) should not affect antithrombotic decisions, although with more than five CMBs the risks of future ICH and ischaemic stroke are finely balanced, and antithrombotics might cause net harm. In lobar ICH populations, a high burden of strictly lobar CMBs is associated with cerebral amyloid angiopathy (CAA) and high ICH risk; antithrombotics should be avoided unless there is a compelling indication 5).

Intravenous recombinant human tissue plasminogen activator for ischemic stroke treatment.

Endovascular intervention for ischemic stroke treatment.

American Heart Association Guidelines for the Early Management of Patients With Acute Ischemic Stroke

see Hypothermia for acute ischemic stroke treatment.


Brain ischemia and treatment are one of the important topics in neurological science. Free oxygen radicals and inflammation formed after ischemia are accepted as the most important causes of damage. Currently, there are studies on many chemopreventive agents to prevent cerebral ischemia damage. The aim of Aras et al is to research the preventive effect of the active ingredient in genistein There is currently no promising pharmacotherapy aside from intravenous or intra-arterial thrombolysis. Yet because of the narrow therapeutic time window involved, thrombolytic application is very restricted in clinical settings. Accumulating data suggest that non-pharmaceutical therapies for stroke might provide new opportunities for stroke treatment 6).

Progression of focal stroke symptoms still constitutes a serious clinical problem for which heparin has insufficient effectiveness in clinical practice. New therapies, ideally preventive, are needed 7).

Omega 3 fatty acid enhance cerebral angiogenesis and provide long-term protection after stroke 8).

After cerebral ischemia, revascularization in the ischemic boundary zone provides nutritive blood flow as well as various growth factors to promote the survival and activity of neurons and neural progenitor cells. Enhancement of angiogenesis and the resulting improvement of cerebral microcirculation are key restorative mechanisms and represent an important therapeutic strategy for ischemic stroke.

Improvements in acute ischemic stroke (AIS) outcomes have been achieved with intravenous thrombolytics (IVT) and intra-arterial thrombolytics vs supportive medical therapy. Given its ease of administration, noninvasiveness, and most validated efficacy, IVT is the standard of care in AIS patients without contraindications to systemic fibrinolysis. However, patients with large-vessel occlusions respond poorly to IVT. Recent trials designed to select this population for randomization to IVT vs IVT with adjunctive endovascular therapy have not shown improvement in clinical outcomes with endovascular therapy. This could be due to the lack of utilization of modern thrombectomy devices such as Penumbra aspiration devices, Solitaire stent-trievers, or Trevo stent-trievers, which have shown the best recanalization results. Continued improvement in the techniques with using these devices as well as randomized controlled trials using them is warranted 9).

With the emergence of new technologies in imaging, thrombolysis and endovascular intervention, the treatment modalities of acute ischemic stroke will enter a new era 10).

Within 3 h from symptom onset, the existence of FLAIR-positive lesions on pretreatment MRI is significantly associated with an increased bleeding risk due to systemic thrombolysis. Therefore, considering FLAIR-positive lesions on baseline MRI might guide treatment decisions in ischemic stroke 11).

see Acute ischemic stroke thrombolysis

see Blood Pressure Management.

Intensive rehabilitation effectively improves physical functions in patients with acute stroke, but the frequency of intervention and its cost-effectiveness are poorly studied. This study aimed to examine the effect of early high-frequency rehabilitation intervention on inpatient outcomes and medical expenses of patients with stroke.

Methods: The study retrospectively included 1759 patients with acute stroke admitted to the Kobe City Medical Center General Hospital between 2013 and 2016. Patients with a transient ischemic attack, subarachnoid hemorrhage, and those who underwent urgent surgery were excluded. Patients were divided into two groups according to the frequency of rehabilitation intervention: the high-frequency intervention group (>2 times/day, n = 1105) and normal-frequency intervention group (<2 times/day, n = 654). A modified Rankin scale score ≤2 at discharge, immobility-related complications and medical expenses were compared between the groups.

Results: The high-frequency intervention group had a significantly shorter time to first rehabilitation (median [interquartile range], 19.0 h [13.1-38.4] vs. 24.7 h [16.1-49.4], P < 0.001) and time to first mobilization (23.3 h [8.7-47.2] vs. 22.8 h [5.7-62.3], P = 0.65) than the normal-frequency intervention group. Despite higher disease severity, the high-frequency intervention group exhibited favorable outcomes at discharge (modified Rankin scale, ≤2; adjusted odds ratio, 1.89; 95% confidence interval, 1.25-2.85; P = 0.002). No significant differences were observed between the two groups concerning the rate of immobility-related complications and total medical expenses during hospitalization.

Conclusions: High-frequency intervention was associated with improved outcomes and decreased medical expenses in patients with stroke. Our results may contribute to reducing medical expenses by increasing the efficiency of care delivery 12).


1)

Jadhav P, Karande M, Sarkar A, Sahu S, Sarmah D, Datta A, Chaudhary A, Kalia K, Sharma A, Wang X, Bhattacharya P. Glial Cells Response in Stroke. Cell Mol Neurobiol. 2022 Jan 23. doi: 10.1007/s10571-021-01183-3. Epub ahead of print. PMID: 35066715.
2)

Yaeger KA, Rossitto CP, Marayati NF, Lara-Reyna J, Ladner T, Hardigan T, Shoirah H, Mocco J, Fifi JT. Time from image acquisition to endovascular team notification: a new target for enhancing acute stroke workflow. J Neurointerv Surg. 2021 Apr 8:neurintsurg-2021-017297. doi: 10.1136/neurintsurg-2021-017297. Epub ahead of print. PMID: 33832969.
3)

Gao J, Kang M, Han Y, Zhang T, Jin H, Kang C. Ginkgolides B alleviates hypoxia-induced PC-12 cell injury by up-regulation of PLK1. Biomed Pharmacother. 2019 Apr 25;115:108885. doi: 10.1016/j.biopha.2019.108885. [Epub ahead of print] PubMed PMID: 31029888.
4)

Levy EI, Munich SA, Rosenwasser RH, Kan P, Thompson BG. Introduction: Endovascular Neurosurgery. Neurosurg Focus. 2019 Jan 1;46(Suppl_1):V1. doi: 10.3171/2019.1.FocusVid.Intro. PubMed PMID: 30611172.
5)

Wilson D, Werring DJ. Antithrombotic therapy in patients with cerebral microbleeds. Curr Opin Neurol. 2016 Nov 24. [Epub ahead of print] PubMed PMID: 27898582.
6)

Chen F, Qi Z, Luo Y, Hinchliffe T, Ding G, Xia Y, Ji X. Non-pharmaceutical therapies for stroke: Mechanisms and clinical implications. Prog Neurobiol. 2014 Jan 6. pii: S0301-0082(13)00147-0. doi: 10.1016/j.pneurobio.2013.12.007. [Epub ahead of print] PubMed PMID: 24407111.
7)

Rödén-Jüllig A, Britton M. Effectiveness of heparin treatment for progressing ischaemic stroke: before and after study. J Intern Med. 2000 Oct;248(4):287-91. PubMed PMID: 11086638.
8)

Wang J, Shi Y, Zhang L, Zhang F, Hu X, Zhang W, Leak RK, Gao Y, Chen L, Chen J. Omega-3 polyunsaturated fatty acids enhance cerebral angiogenesis and provide long-term protection after stroke. Neurobiol Dis. 2014 Apr 29. pii: S0969-9961(14)00103-X. doi: 10.1016/j.nbd.2014.04.014. [Epub ahead of print] PubMed PMID: 24794156.
9)

Serrone JC, Jimenez L, Ringer AJ. The role of endovascular therapy in the treatment of acute ischemic stroke. Neurosurgery. 2014 Feb;74 Suppl 1:S133-41. doi: 10.1227/NEU.0000000000000224. PubMed PMID: 24402482.
10)

Lu AY, Ansari SA, Nyström KV, Damisah EC, Amin HP, Matouk CC, Pashankar RD,Bulsara KR. Intra-arterial treatment of acute ischemic stroke: the continued evolution. Curr Treat Options Cardiovasc Med. 2014 Feb;16(2):281. doi:10.1007/s11936-013-0281-2. PubMed PMID: 24398801.
11)

Hobohm C, Fritzsch D, Budig S, Classen J, Hoffmann KT, Michalski D. Predicting intracerebral hemorrhage by baseline magnetic resonance imaging in stroke patients undergoing systemic thrombolysis. Acta Neurol Scand. 2014 Jul 18. doi: 10.1111/ane.12272. [Epub ahead of print] PubMed PMID: 25040041.
12)

Oyanagi K, Kitai T, Yoshimura Y, Yokoi Y, Ohara N, Kohara N, Sakai N, Honda A, Onishi H, Iwata K. Effect of early intensive rehabilitation on the clinical outcomes of patients with acute stroke. Geriatr Gerontol Int. 2021 Jun 8. doi: 10.1111/ggi.14202. Epub ahead of print. PMID: 34101957.

Magnetic resonance guided focused ultrasound thalamotomy for essential tremor

Magnetic resonance guided focused ultrasound thalamotomy for essential tremor

Magnetic resonance guided focused ultrasound is a minimally invasive surgical procedure for symptomatic treatment of Parkinson Disease. With this technology, the ventral intermediate nucleusSTN, and internal globus pallidus have been targeted for therapeutic cerebral ablation, while also minimizing the risk of hemorrhage and infection from more invasive neurosurgical procedures.

In a pilot study published in 2013, essential tremor improved in 15 patients treated with magnetic resonance guided focused ultrasound thalamotomy1).

Clinical trials have confirmed the efficacy of focused ultrasound (FUS) thalamotomy in essential tremor, but its effectiveness and safety for managing tremor-dominant Parkinson disease (TDPD) is unknown.

It might change the way that patients with essential tremor and potentially other disorders are treated 2).

The post-treatment effectiveness was evaluated using the clinical rating scale for tremors. Thalamic MRgHIFU had substantial therapeutic effects on patients, based on MRgHIFU-mediated improvements in movement control and significant changes in brain mu rhythms. Ultrasonic thalamotomy may reduce hyper-excitable activity in the motor cortex, resulting in normalized behavioral activity after sonication treatment. Thus, non-invasive and spatially accurate MRgHIFU technology can serve as a potent therapeutic tool with broad clinical applications 3).

Magnetic resonance guided focused ultrasound (MRgFUS) for thalamotomy is a safe, effective and less-invasive surgical method for treating medication-refractory essential tremor (ET). However, several issues must be resolved before clinical application of MRgFUS, including optimal patient selection and management of patients during treatment 4).

Jung et al. found different MRI pattern evolution after MRgFUS for white matter and gray matter. Their results suggest that skull characteristics, such as low skull density, should be evaluated prior to MRgFUS to successfully achieve thermal rise 5).

In a large academic medical center in the mid-Atlantic region, the Department of Neurosurgery conducted a continued access study, recently approved by the Food and Drug Administration, to evaluate the effectiveness of transcranial FUS thalamotomy for the treatment of medication-refractory ET.

One patient’s experience will be introduced, including discussion of evidence-based treatment options for ET and information on the nursing management of the patient undergoing FUS thalamotomy 6).

A PubMed search was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if hand tremor scores (HTS), total Clinical Rating Scale for Tremor (CRST) scores, or Quality of Life in Essential Tremor Questionnaire (QUEST) scores at regular intervals following MRgFUS treatment for essential tremor were documented. Data analyses included a random effects model of meta-analysis and mixed-effects model of meta-regression. Twenty-one articles reporting HTS for 395 patients were included. Mean pre-operative HTS was 19.2 ± 5.0. Mean HTS at 3 months post-treatment was 7.4 ± 5.0 (61.5% improvement, p < 0.001). Treatment effect was mildly decreased at 36 months at 9.1 ± 5.4 (8.8% reduction). Meta-regression of time since treatment as a modifier of HTS revealed a downward trend in effect size, though this was not statistically significant (p = 0.208). Only 4 studies included follow-up ≥ 24 months. Thirteen included articles reported total CRST scores with standardized follow-up for 250 patients. Mean pre-operative total CRST score decreased by 46.2% at 3 months post-treatment (p < 0.001). Additionally, mean QUEST scores at 3 months post-treatment significantly improved compared to baseline (p < 0.001). HTS is significantly improved from baseline ≥ 24 months post-treatment and possibly ≥ 48 months post-treatment. There is a current paucity of long-term CRST and QUEST score reporting in the literature 7).

In a double-blinded, prospective, sham-controlled randomized controlled trial of MR-guided focused ultrasound thalamotomy for treatment of tremor-dominant PD, 62% of treated patients demonstrated improvement in tremor scores from baseline to 3 months postoperatively, as compared to 22% in the sham group. There has been only one open-label trial of MR-guided focused ultrasound subthalamotomy for patients with PD, demonstrating improvements of 71% for rigidity, 36% for akinesia, and 77% for tremor 6 months after treatment. Among the two open-label trials of MR-guided focused ultrasound pallidotomy for patients with PD, dyskinesia and overall motor scores improved up to 52% and 45% at 6 months postoperatively. Although MR-guided focused ultrasound thalamotomy is now approved by the U.S. Food and Drug Administration for treatment of parkinsonian tremor, additional high-quality randomized controlled trials are warranted and are underway to determine the safety and efficacy of MR-guided focused ultrasound subthalamotomy and pallidotomy for treatment of the cardinal features of PD. These studies will be paramount to aid clinicians to determine the ideal ablative target for individual patients. Additional work will be required to assess the durability of MR-guided focused ultrasound lesions, ideal timing of MR-guided focused ultrasound ablation in the course of PD, and the safety of performing bilateral lesions 8).

see Magnetic resonance guided focused ultrasound thalamotomy for essential tremor case series.

A 55-yr-old man with a history of right frontal craniotomy for resection of a colloid cyst underwent a left ventrointermedius nucleus thalamotomy through MRgFUS. The prior craniotomy flap was not excluded in the treatment plan; however, all bony defects and hardware were marked as “no-pass” regions. Clinical outcomes were collected at the 6-mo follow-up.

Transducer elements whose acoustic paths would have been altered by the craniotomy defect were turned off. Sonications reaching lesional temperatures of up to 56°C were successfully delivered. The procedure was well-tolerated, without any persistent intra-ablation or post-ablation adverse effects. The presence of a lesion was confirmed on MRI, which was associated with a significant reduction in the patient’s tremor that was sustained at the 6-mo follow-up.

This case demonstrates the safety and efficacy of MRgFUS thalamotomy in a patient with prior craniotomies and highlights our strategy for acoustic lesioning in this setting 9).


De Vloo et al. reported on an ET patient who underwent an Magnetic resonance guided focused ultrasound thalamotomy but experienced tremor recurrence. They expanded the MRgFUS-induced thalamic cavity using radiofrequency (RF), with good effect on the tremor but transient sensorimotor deficits and permanent ataxia. This is the first report of a patient undergoing RF thalamotomy after an unsuccessful MRgFUS thalamotomy. As they used microelectrode recording to guide the RF thalamotomy, they could also study for the first time the electrophysiological properties of previously sonicated thalamic neurons bordering the MRgFUS-induced cavity. These neurons displayed electrophysiological characteristics identical to those recorded from nonsonicated thalamic cells in ET patients. Hence, this findings support the widespread assumption that sonication below the necrotic threshold does not permanently alter neuronal function 10).



1)

Elias WJ, Huss D, Voss T, Loomba J, Khaled M, Zadicario E, Frysinger RC, Sperling SA, Wylie S, Monteith SJ, Druzgal J, Shah BB, Harrison M, Wintermark M. A pilot study of focused ultrasound thalamotomy for essential tremor. N Engl J Med. 2013 Aug 15;369(7):640-8. doi: 10.1056/NEJMoa1300962. PubMed PMID: 23944301.
2)

Lipsman N, Schwartz ML, Huang Y, Lee L, Sankar T, Chapman M, Hynynen K, Lozano AM. MR-guided focused ultrasound thalamotomy for essential tremor: a proof-of-concept study. Lancet Neurol. 2013 May;12(5):462-8. doi: 10.1016/S1474-4422(13)70048-6. Epub 2013 Mar 21. PubMed PMID: 23523144.
3)

Chang JW, Min BK, Kim BS, Chang WS, Lee YH. Neurophysiologic correlates of sonication treatment in patients with essential tremor. Ultrasound Med Biol. 2015 Jan;41(1):124-31. doi: 10.1016/j.ultrasmedbio.2014.08.008. Epub 2014 Oct 22. PubMed PMID: 25438838.
4)

Chang WS, Jung HH, Kweon EJ, Zadicario E, Rachmilevitch I, Chang JW. Unilateral magnetic resonance guided focused ultrasound thalamotomy for essential tremor: practices and clinicoradiological outcomes. J Neurol Neurosurg Psychiatry. 2015 Mar;86(3):257-64. doi: 10.1136/jnnp-2014-307642. Epub 2014 May 29. PubMed PMID: 24876191.
5)

Jung HH, Chang WS, Rachmilevitch I, Tlusty T, Zadicario E, Chang JW. Different magnetic resonance imaging patterns after transcranial magnetic resonance-guided focused ultrasound of the ventral intermediate nucleus of the thalamus and anterior limb of the internal capsule in patients with essential tremor or obsessive-compulsive disorder. J Neurosurg. 2015 Jan;122(1):162-8. doi: 10.3171/2014.8.JNS132603. PubMed PMID: 25343176.
6)

Shaw KD, Johnston AS, Rush-Evans S, Prather S, Maynard K. Nursing Management of the Patient Undergoing Focused Ultrasound: A New Treatment Option for Essential Tremor. J Neurosci Nurs. 2017 Aug 16. doi: 10.1097/JNN.0000000000000301. [Epub ahead of print] PubMed PMID: 28817495.
7)

Miller WK, Becker KN, Caras AJ, Mansour TR, Mays MT, Rashid M, Schwalb J. Magnetic resonance-guided focused ultrasound treatment for essential tremor shows sustained efficacy: a meta-analysis. Neurosurg Rev. 2021 May 12. doi: 10.1007/s10143-021-01562-w. Epub ahead of print. PMID: 33978922.
8)

Moosa S, Martínez-Fernández R, Elias WJ, Del Alamo M, Eisenberg HM, Fishman PS. The role of high-intensity focused ultrasound as a symptomatic treatment for Parkinson’s disease. Mov Disord. 2019 Jul 10. doi: 10.1002/mds.27779. [Epub ahead of print] Review. PubMed PMID: 31291491.
9)

Wathen C, Yang AI, Hitti FL, Henry L, Chaibainou H, Baltuch GH. Feasibility of Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Essential Tremor in the Setting of Prior Craniotomy. Oper Neurosurg (Hagerstown). 2022 Feb 1;22(2):61-65. doi: 10.1227/ONS.0000000000000012. PMID: 35007218.
10)

De Vloo P, Milosevic L, Gramer RM, et al. Microelectrode Recording and Radiofrequency Thalamotomy following Focused Ultrasound Thalamotomy [published online ahead of print, 2020 Sep 16]. Stereotact Funct Neurosurg. 2020;1-4. doi:10.1159/000510109
WhatsApp WhatsApp us
%d bloggers like this: