American Society for Stereotactic and Functional Neurosurgery

American Society for Stereotactic and Functional Neurosurgery

Magnetic resonance image-guided laser interstitial thermal therapy (MRgLITT) is a tool in the neurosurgical armamentarium for the management of drug-resistant epilepsy. Given the introduction of this technology, the American Society for Stereotactic and Functional Neurosurgery (ASSFN), which acts as the joint section representing the field of stereotactic and functional neurosurgery on behalf of the Congress of Neurological Surgeons and the American Association of Neurological Surgeons, provides here the expert consensus opinion on evidence-based best practices for the use and implementation of this treatment modality. Indications for treatment are outlined, consisting of failure to respond to, or intolerance of, at least 2 appropriately chosen medications at appropriate doses for disabling, localization-related epilepsy in the setting of well-defined epileptogenic foci, or critical pathways of seizure propagation accessible by MRgLITT. Applications of MRgLITT in mesial temporal lobe epilepsy and hypothalamic hamartoma, along with its contraindications in the treatment of epilepsy, are discussed based on current evidence. To put this position statement in perspective, they detailed the evidence and authority on which this ASSFN position statement is based 1)

A persistent underuse of epilepsy surgery exists. Neuromodulation treatments including deep brain stimulation (DBS) expand the surgical options for patients with epilepsy and provide options for patients who are not candidates for resective surgery. DBS of the bilateral anterior nucleus of the thalamus is an Food and Drug Administration-approved, safe, and efficacious treatment option for patients with refractory focal epilepsy. The purpose of this consensus position statement is to summarize evidence, provide recommendations, and identify indications and populations for future investigation in Deep Brain Stimulation for epilepsy. The recommendations of the American Society for Stereotactic and Functional Neurosurgery are based on several randomized and blinded clinical trials with high-quality data to support the use of DBS to the anterior nucleus of the thalamus for the treatment of refractory focal-onset seizures.

Cabrera et al. designed a 51-question online survey comprising Likert-type, multiple-choice, and rank-order questions and distributed it to members of the American Society for Stereotactic and Functional Neurosurgery (ASSFN). Descriptive and inferential statistical analyses were performed on the data.

They received 38 completed surveys. Half (n = 19) of responders reported devoting at least a portion of their clinical practice to psychiatric neurosurgery, utilizing DBS and treating obsessive compulsive disorder (OCD) most frequently overall. Respondents indicated that psychiatric neurosurgery is more medically effective (OR 0, p = 0.03242, two-sided Fisher’s exact test) and has clearer clinical indications for the treatment of OCD than for the treatment of depression (OR 0.09775, p = 0.005137, two-sided Fisher’s exact test). Seventy-one percent of all respondents (n = 27) supported the clinical utility of ablative surgery in modern neuropsychiatric practice, 87% (n = 33) agreed that ablative procedures constitute a valid treatment alternative to DBS for some patients, and 61% (n = 23) agreed that ablative surgery may be an acceptable treatment option for patients who are unlikely to comply with postoperative care.

This up-to-date account of practices, perceptions, and predictions about psychiatric neurosurgery contributes to the knowledge about evolving attitudes over time and informs priorities for education and further surgical innovation on the psychiatric neurosurgery landscape 2).


2016 Biennial Meeting of the American Society for Stereotactic and Functional Neurosurgery, Chicago, IL, USA, June 18-21, 2016: Abstracts 3)


Wu C, Schwalb JM, Rosenow JM, McKhann GM 2nd, Neimat JS; American Society for Stereotactic and Functional Neurosurgeons. The American Society for Stereotactic and Functional Neurosurgery Position Statement on Laser Interstitial Thermal Therapy for the Treatment of Drug-Resistant Epilepsy. Neurosurgery. 2022 Feb 1;90(2):155-160. doi: 10.1227/NEU.0000000000001799. PMID: 34995216.

Cabrera LY, Courchesne C, Kiss ZHT, Illes J. Clinical Perspectives on Psychiatric Neurosurgery. Stereotact Funct Neurosurg. 2019;97(5-6):391-398. doi: 10.1159/000505080. Epub 2020 Jan 17. PMID: 31955163.

2016 Biennial Meeting of the American Society for Stereotactic and Functional Neurosurgery, Chicago, IL, USA, June 18-21, 2016: Abstracts. Stereotact Funct Neurosurg. 2017 Jan 16;94 Suppl 2:1-77. doi: 10.1159/000455386. [Epub ahead of print] PubMed PMID: 28092908.

Resective epilepsy surgery

Resective epilepsy surgery

Resective epilepsy surgery based on an invasive EEG-monitors performed with subdural grids (SDG) or depth electrodes (stereoelectroencephalographySEEG) is considered to be the best option towards achieving seizure-free state in drug resistant epilepsy.

Despite good outcomes from high-quality clinical trials, referrals of patients with seizures refractory to medical treatment remain infrequent 1).

Three RCTs (two adult RCTs and one pediatric RCT) consistently supported the efficacy of resective surgery as treatment for epilepsy with semiology localized to the mesial temporal lobe. In these studies, 58-100% of the patients who underwent resective surgery achieved seizure freedom, in comparison to 0-13% of medically treated patients. In another RCT, the likelihood of seizure freedom after resective surgery was independent of the surgical approach (transSylvian [64%] versus subtemporal [62%]). Two other RCTs demonstrated that hippocampal resection is essential to optimize seizure control. But, no significant gain in seizure control was achieved beyond removing 2.5 cm of the hippocampus. Across RCTs, minor complications (deficit lasting < 3 months) and major complications (deficit > 3 months) ranged 2-5% and 5-11% respectively. However, nonincapacitating superior subquadrantic visual-field defects (not typically considered a minor or major complication) were noted in up to 55% of the surgical cohort. The available RCTs provide compelling support for resective surgery as a treatment for mesial temporal lobe epilepsy and offer insights toward optimal surgical strategy 2)

Complete removal of the epileptogenic zone significantly increases the chances for postoperative seizure-freedom. In complex surgical candidates, delineation of the epileptogenic zone requires a long-term invasive video/EEG from intracranial electrodes. It is especially challenging to achieve a complete resection in deep brain structures such as opercular insular cortex 3).

Belohlavkova et al. retrospectively reviewed data of pediatric patients operated in Motol Epilepsy Center between October 2010 and June 2020 who underwent resections guided by intraoperative visual detection of depth electrodes following SEEG. The outcome in terms of seizure- and AED-freedom was assessed individually in each patient.

Nineteen patients (age at surgery 2.9-18.6 years, median 13 years) were included in the study. The epileptogenic zone involved opercular insular cortex in eighteen patients. The intraoperative detection of the electrodes was successful in seventeen patients and the surgery was regarded complete in sixteen. Thirteen patients were seizure-free at final follow-up including six drug-free cases. The successful intraoperative detection of the electrodes was associated with favorable outcome in terms of achieving complete resection and seizure-freedom in most cases. On the contrary, the patients in whom the procedure failed had poor postsurgical outcome.

The reported technique helps to achieve the complete resection in challenging patients with the epileptogenic zone in deep brain structures 4)

81 patients with tuberous sclerosis complex (TSC) who had undergone resective epilepsy surgery at Sanbo Brain Hospital, between April 2004 and June 2019. They estimated the cumulative probability of remaining seizure-free and plotted survival curves. Variables were compared using Mann-Whitney U, Pearson’s correlation, continuity correction, and Fisher’s exact chi-square tests. Prognostic predictors were analyzed using log-rank (Mantel-Cox) tests and Cox regression models.

At the last follow-up, 48 (59.3%) patients were classified as International League Against Epilepsy Class 1 (including 14 patients who had seizures <3 times postoperatively on the same or different day and were seizure-free at all other times). The estimated cumulative probability of remaining seizure-free postoperatively was 69.0% (95% confidence interval [CI] 58.8-79.2%), 61.9% (95% CI 51.1-72.7%), and 55.0% (95% CI 42.8-67.2%) at 2, 5, and 10 years, respectively. The mean time of remaining seizure-free was 7.24 ± 0.634 years (95% CI 6.00-8.49); en bloc resection was an essential positive predictor of postoperative seizure freedom, as was age at seizure onset, regional interictal video-electroencephalography pattern, and temporal lobe surgery. The longer the seizure-free time, the less likely a relapse. Patients who postoperatively experienced seizures remained likely to recover.

They demonstrated the efficacy of tuberous sclerosis complex treatment and intractable epilepsy with surgery. Detailed perioperative tests are a reliable predictor of postoperative seizure freedom 5)


Jobst BC, Cascino GD. Resective epilepsy surgery for drug-resistant focal epilepsy: a review. JAMA. 2015 Jan 20;313(3):285-93. doi: 10.1001/jama.2014.17426. PMID: 25602999.

Cramer SW, McGovern RA, Wang SG, Chen CC, Park MC. Resective epilepsy surgery: assessment of randomized controlled trials. Neurosurg Rev. 2021 Aug;44(4):2059-2067. doi: 10.1007/s10143-020-01432-x. Epub 2020 Nov 9. PMID: 33169227.
3) , 4)

Belohlavkova A, Jahodova A, Kudr M, Benova B, Ebel M, Liby P, Taborsky J, Jezdik P, Janca R, Kyncl M, Tichy M, Krsek P. May intraoperative detection of stereotactically inserted intracerebral electrodes increase precision of resective epilepsy surgery? Eur J Paediatr Neurol. 2021 Sep 25;35:49-55. doi: 10.1016/j.ejpn.2021.09.012. Epub ahead of print. PMID: 34610561.

Huang Q, Zhou J, Wang X, Li T, Wang M, Wang J, Teng P, Qi X, Zhu M, Luan G, Zhai F. Predictors and Long-term Outcome of Resective Epilepsy Surgery in Patients with Tuberous Sclerosis Complex: A Single-centre Retrospective Cohort Study. Seizure. 2021 Mar 25;88:45-52. doi: 10.1016/j.seizure.2021.03.022. Epub ahead of print. PMID:

Brainstem Neurosurgery

Brainstem Neurosurgery

by Michael Ghali (Author), George Ghali (Author)

List Price: $199.33


Microsurgical operations in the vicinity of the bulb or its intraaxial contents is frequently fraught with operator angst and catastrophic neurologic deficits. Accordingly, the most rudimentary of Nature’s beautiful creations also happens to be among its most complex and delicate. The brainstem houses the core circuitry generating sympathetic tone and a breathing rhythm which maintain Life. The reticular activating propriobulbar circuitry diffusely projects and activates cerebral cortex directly and through thalamic relay nuclei to maintain Vigilance. Cranial nerve motor nuclei control the movements of the head and neck and cranial sensory nuclei represent the initial relays transmitting somatosensory information of the face and cephaloviscera to the ventral posterior medial thalamic nuclei. These nuclei are complexly, though discretely and wisely organized within its interior and multimodally modulated by suprabulbar and peripheral influences. Haphazard microsurgical maneuvers or the slightest transgression upon one of its critical structures may hasten and expedite a patient’s rapid demise. Fortuitously, innovation in microsurgical techniques by the works of Emeritus Professor Dr. Robert F. Spetzler and Emeritus Professor Dr. Albert I. Rhoton has provided us with an elegant set of operative steps to achieve the safe and effective removal of pathology sans deficit, rendering the safe removal of previously inoperable neoplastic and vascular lesions commonplace and facile. Familiarity, versatility, and comfort with the faithful performance of these techniques augment the neurosurgeon’s armamentarium and confidence to intervene upon brainstem proximate and intraaxial pathology.

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