Somatic complications of epilepsy surgery over 25 years at a single center

The surgical interval between robot-assisted SEEG and epilepsy resection surgery is an influencing factor of SSI

BACKGROUND

In recent years, the development of robotic neurosurgery has brought many benefits to patients, but there are few studies on the occurrence of surgical site infection (SSI) after robot-assisted stereoelectroencephalography (SEEG). The purpose of this study was to collect relevant data from robot-assisted SEEG over the past ten years and to analyze the influencing factors and economic burden of surgical site infection.

METHODS

Basic and surgical information was collected for all patients who underwent robot-assisted SEEG from January 2014 to December 2023. Logistic regression was used to analyze the factors influencing SSI according to different subgroups (radiofrequency thermocoagulation or epilepsy resection surgery).

RESULTS

A total of 242 subjects were included in this study. The risk of SSI in the epilepsy resection surgery group (18.1%) was 3.5 times greater than that in the radiofrequency thermocoagulation group (5.1%) (OR 3.49, 95% CI 1.39 to 9.05); this difference was statistically significant. SSI rates in the epilepsy resection surgery group were associated with shorter surgical intervals (≤ 9 days) and higher BMI (≥ 23 kg/m2) (6.1 and 5.2 times greater than those in the control group, respectively). Hypertension and admission to the intensive care unit (ICU) were risk factors for SSI in the radiofrequency thermocoagulation group. Patients with SSIs had $21,231 more total hospital costs, a 7-day longer hospital stay, and an 8-day longer postoperative hospital stay than patients without SSI.

CONCLUSIONS

The incidence of SSI in patients undergoing epilepsy resection after stereoelectroencephalography was higher than that in patients undergoing radiofrequency thermocoagulation. For patients undergoing epilepsy resection surgery, prolonging the interval between stereoelectroencephalography and epilepsy resection surgery can reduce the risk of SSI; At the same time, for patients receiving radiofrequency thermocoagulation treatment, it is not recommended to enter the ICU for short-term observation if the condition permits.

Back to Basics: Care of the Stereotactic EEG Implanted Patient

PURPOSE

Stereotactic EEG (SEEG) is gaining increasing popularity in the United States. Patients undergoing SEEG have unique challenges, and their needs are different compared with noninvasive cases. We aim to describe the medical, nursing, and other institutional practices of SEEG evaluations among tertiary referral (level IV) epilepsy centers accredited by the National Association of Epilepsy Centers.

METHODS

We analyzed data obtained from a Research Electronic Data Capture (REDCap) survey we formulated and distributed to directors of all level IV epilepsy centers listed by the National Association of Epilepsy Center. Most questions were addressed to the adult and pediatric SEEG programs separately.

RESULTS

Among 199 epilepsy center directors invited to complete the survey, 90 (45%) responded. Eighty-three centers (92%) reported they perform SEEG evaluations. Of the 83 respondents, 56 perform SEEG in adult and 47 in pediatric patients. Twenty-two centers evaluate both pediatric and adult subjects. The highest concordance of SEEG workflow was in (1) epilepsy monitoring unit stay duration (1-2 weeks, 79% adult and 85% pediatric programs), (2) use of sleep deprivation (94% both adult and pediatric) and photic stimulation (79% adult and 70% pediatric) for seizure activation, (3) performing electrical cortical stimulation at the end of SEEG evaluation after spontaneous seizures are captured (84% adult and 88% pediatric), and (4) daily head-wrap inspection (76% adult and 80% pediatric). Significant intercenter variabilities were noted in the other aspects of SEEG workflow.

CONCLUSIONS

Results showed significant variability in SEEG workflow across polled centers. Prospective, multicenter protocols will help the future development and harmonization of optimal practice patterns.

Complicated epilepsy surgery: importance of balancing benefit and deficit

The risk-benefit ratio of epilepsy surgery needs careful consideration, is different for each individual and requires a careful, informed dialogue between the person concerned and their medical advisers. We illustrate this process with Virginia, who has had refractory focal epilepsy from age 1 year and a left hemiparesis. At the age of 45 years, we discussed the possibility of epilepsy surgery and went through non-invasive investigations with structural and functional MRI, tractography, scalp video-EEG telemetry, neuropsychological and neuropsychiatric evaluations. This was followed by a decision to carry out intracranial EEG to define the area of seizure onset and its relation to an area of focal cortical dysplasia, eloquent cortex and tracts. We agreed to carry out a focal resection in the knowledge that this would result in a loss of left-hand function. One year later, Virginia is seizure-free on reduced medication. We describe the steps in the process with Virginia's views.

Surgical Outcome of Pharmaco Refractory Epilepsy in the National Epilepsy Center of Sri Lanka

BACKGROUND

The National Epilepsy Center (NEC) in Sri Lanka was established in 2017. Seizure outcome, effects on quality of life (QOL) and surgical complications among nonpediatric patients who underwent epilepsy surgery from October 2017 to February 2023 are described.

METHODS

Nineteen patients (≥14 years) underwent epilepsy surgery at the NEC. We used Engel classification and Quality of Life in Epilepsy 31 (QOLIE-31) questionnaire to assess seizure outcome and QOL respectively. Surgical complications were categorized into neurological and complications related to surgery.

RESULTS

Nine female and 10 male patients underwent surgery (mean age 27.5 years (range 14-44 years). The mean follow-up duration was 10.5 months (range 6-55 months). Twelve patients underwent temporal lobe resections. At 6-months follow-up, 83.3% (10/12) had favorable seizure outcomes with Engel class I/II. At 1-year follow-up 6/8 patients (75.0%) and at 2-year follow-up, 5/7 patients (71.4%) had a favorable outcome. Seven patients had extra-temporal lobe surgeries and one defaulted. Seizure freedom was observed in 6/6 at 6 months, 3/3 at 1-year, and 2/2 at 2-year follow-up. Five patients (26.3%) experienced minor post-operative surgical site infection. Two (11.1%) had persistent quadrantanopia. Meaningful improvement in QOL (change in QOLIE-31 score ≥11.8) was observed irrespective of seizure outcome or type of surgery (P < 0.001).

CONCLUSIONS

Epilepsy surgery is effective in developing countries. Seizure outcomes in our patients are comparable to those worldwide. Clinically important QOL improvement was observed in our series. This is the first published data on epilepsy surgery outcomes in nonpediatric patients from Sri Lanka.

The comparison of the watertight and non-watertight dural closure in supratentorial craniotomy: A single-institute 10-year experience with 698 patients

Watertight dural closure (WTDC) is considered crucial by many neurosurgeons in cranial base surgery, infratentorial craniotomy, and spinal intradural procedure. Whether WTDC also reduce complications remains controversial in supratentorial craniotomy. The objective of this study is to investigate the relationship between WTDC and CSF-related complications in supratentorial craniotomy for the resection of space-occupying lesions. A retrospective analysis of patients who suffered from intracranial space-occupying lesions at Beijing Ditan Hospital between January 2011 and December 2021 was conducted. A total of 698 cases were reviewed with attention to the operative approach, subgaleal fluid collection, wound healing impairment, postoperative infection, and post-craniotomy headaches. The study included a total of 423 patients with WTDC and 275 patients without WTDC. Patients without WTDC had a significantly higher rate of infection (10.9% vs 4.5% with WTDC, P = .001). The rate of subgaleal fluid collection was 9.7% in the WTDC group and 11.3% in the non-WTDC group, but this difference was not statistically significant (P = .502). They suffered from a greater incidence of post-craniotomy headaches in the WTDC group (13.5% vs 9.5% in the non-WTDC group), but without statistical significance (P = .109). We also found no difference in wound healing impairment (P = .719). There is less postoperative infection associated with WTDC during intracranial space-occupying lesion removal than without WTDC in supratentorial craniotomy.

Development and results of the epilepsy surgery in Armenia: hope for a better future

Purpose

We present our experience with the national epilepsy surgery program in Armenia by tracing the development of epilepsy surgery in the largest pediatric neurology department at "Arabkir" Medical Center. This development was possible on the basis of a strong collaboration with the Epilepsy Surgery center at the University Hospital "Sofia St. Ivan Rilski," Sofia, Bulgaria.

Materials and methods

Our material included 28 consecutive patients with lesional drug-resistant epilepsy evaluated. All patients underwent 3 T MRI and Video-EEG monitoring. Brain 18FDG-PET was done in 13 patients in St. Petersburg. Fifteen patients (53%) had preoperative neuropsychological examination before surgery. All operations were done by the same neurosurgical team on site in Arabkir Hospital.

Results

The majority of the patients in our cohort benefited from the epilepsy surgery as 25 (89%) are free of disabling seizures (Engel class I) and three patients (11%) did not improve substantially (Engel class IV). Eleven patients (39%) are already ASM-free after surgery, 4 (14%) are on monotherapy, 11(39%) get two drugs, and 2(7%) are on polytherapy, one of them still continues having seizures. In 12 patients (43%), we were able either to withdraw therapy or to decrease one of the ASM.

Conclusion

We believe that, although small, yet encompassing patients along the usual age spectrum and with the most frequent pathologies of drug-resistant epilepsies, our experience can serve as a model to develop epilepsy surgery in countries with limited resources.

Magnetic resonance-guided laser interstitial thermal therapy for drug-resistant epilepsy: A systematic review and individual participant data meta-analysis

Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has emerged as a popular minimally invasive alternative to open resective surgery for drug-resistant epilepsy (DRE). We sought to perform a systematic review and individual participant data meta-analysis to identify independent predictors of seizure outcome and complications following MRgLITT for DRE. Eleven databases were searched from January 1, 2010 to February 6, 2021 using the terms "MR-guided ablation therapy" and "epilepsy". Multivariable mixed-effects Cox and logistic regression identified predictors of time to seizure recurrence, seizure freedom, operative complications, and postoperative neurological deficits. From 8705 citations, 46 studies reporting on 450 MRgLITT DRE patients (mean age = 29.5 ± 18.1 years, 49.6% female) were included. Median postoperative seizure freedom and follow-up duration were 15.5 and 19.0 months, respectively. Overall, 240 (57.8%) of 415 patients (excluding palliative corpus callosotomy) were seizure-free at last follow-up. Generalized seizure semiology (hazard ratio [HR] = 1.78, p = .020) and nonlesional magnetic resonance imaging (MRI) findings (HR = 1.50, p = .032) independently predicted shorter time to seizure recurrence. Cerebral cavernous malformation (CCM; odds ratio [OR] = 7.97, p < .001) and mesial temporal sclerosis/atrophy (MTS/A; OR = 2.21, p = .011) were independently associated with greater odds of seizure freedom at last follow-up. Operative complications occurred in 28 (8.5%) of 330 patients and were independently associated with extratemporal ablations (OR = 5.40, p = .012) and nonlesional MRI studies (OR = 3.25, p = .017). Postoperative neurological deficits were observed in 53 (15.1%) of 352 patients and were independently predicted by hypothalamic hamartoma etiology (OR = 5.93, p = .006) and invasive electroencephalographic monitoring (OR = 4.83, p = .003). Overall, MRgLITT is particularly effective in treating patients with well-circumscribed lesional DRE, such as CCM and MTS/A, but less effective in nonlesional cases or lesional cases with a more diffuse epileptogenic network associated with generalized seizures. This study identifies independent predictors of seizure freedom and complications following MRgLITT that may help further guide patient selection.

Transuncal Selective Amygdalohippocampectomy by an Inferolateral Preseptal Endoscopic Approach Through Inferior Eyelid Conjunctival Incision: An Anatomic Study

BACKGROUND

Transorbital endoscopic approaches have been described for pathologies of anterior and middle fossae. Standard lateral orbitotomy gives access to mesial temporal lobe, but the axis of work is partially obscured by the temporal pole and working corridor is limited.

OBJECTIVE

To evaluate the usefulness of an inferolateral orbitotomy to provide a more direct corridor to perform a transuncal selective amygdalohippocampectomy.

METHODS

Three adult cadaveric specimens were used for a total of 6 dissections. A step-by-step description and illustration of the transuncal corridor for a selective amygdalohippocampectomy were performed using the inferolateral orbitotomy through an inferior eyelid conjunctival incision. The anatomic landmarks were demonstrated in detail. Orbitotomies and angles of work were measured from computed tomography scans, and the area of resection was illustrated by postdissection MRI.

RESULTS

Inferior eyelid conjunctival incision was made for exposure of the inferior orbital rim. Inferolateral transorbital approach was performed to access the transuncal corridor. Endoscopic selective amygdalohippocampectomy was performed through the entorhinal cortex without damage to the temporal neocortex or Meyer's loop. The mean horizontal diameter of the osteotomy was 14.4 mm, and the vertical one was 13.6 mm. The mean angles of work were 65° and 35.5° in the axial and sagittal planes, respectively. Complete amygdalohippocampectomy was achieved in all 6 dissections.

CONCLUSION

Transuncal selective amygdalohippocampectomy was feasible in cadaveric specimens using the inferolateral transorbital endoscopic approach avoiding damage to the temporal neocortex and Meyer's loop. The inferior eyelid conjunctival incision may result in an excellent cosmetic outcome.

Intraarterial encephalography from an acutely implanted aneurysm embolization device in awake humans

OBJECTIVE

Endovascular electroencephalography (evEEG) uses the cerebrovascular system to record electrical activity from adjacent neural structures. The safety, feasibility, and efficacy of using the Woven EndoBridge Aneurysm Embolization System (WEB) for evEEG has not been investigated.

METHODS

Seventeen participants undergoing awake WEB endovascular treatment of unruptured cerebral aneurysms were included. After WEB deployment and before detachment, its distal deployment wire was connected to an EEG receiver, and participants performed a decision-making task for 10 minutes. WEB and scalp recordings were captured.

RESULTS

All patients underwent successful embolization and evEEG with no complications. Event-related potentials were detected on scalp EEG in 9/17 (53%) patients. Of these 9 patients, a task-related low-gamma (30-70 Hz) response on WEB channels was captured in 8/9 (89%) cases. In these 8 patients, the WEB was deployed in 2 middle cerebral arteries, 3 anterior communicating arteries, the terminal internal carotid artery, and 2 basilar tip aneurysms. Electrocardiogram artifact on WEB channels was present in 12/17 cases.

CONCLUSIONS

The WEB implanted within cerebral aneurysms of awake patients is capable of capturing task-specific brain electrical activities. Future studies are warranted to establish the efficacy of and support for evEEG as a tool for brain recording, brain stimulation, and brain-machine interface applications.

Hippocampal resection in temporal lobe epilepsy: Do we need to resect the tail?

INTRODUCTION

Anteromesial temporal lobe resection is the most common surgical technique used to treat drug-resistant mesial temporal lobe epilepsy, particularly when secondary to hippocampal sclerosis. Structural and functional imaging data suggest the importance of sparing the posterior hippocampus for minimising language and memory deficits. Recent work has challenged the view that maximal posterior hippocampal resection improves seizure outcome. This study was designed to assess whether resection of posterior hippocampal atrophy was associated with improved seizure outcome.

METHODS

Retrospective analysis of a prospective database of all anteromesial temporal lobe resections performed in individuals with hippocampal sclerosis at our epilepsy surgery centre, 2013-2021. Pre- and post-operative MRI were reviewed by 2 neurosurgical fellows to assess whether the atrophic segment, displayed by automated hippocampal morphometry, was resected, and ILAE seizure outcomes were collected at 1 year and last clinical follow-up. Data analysis used univariate and binary logistic regression.

RESULTS

Sixty consecutive eligible patients were identified of whom 70% were seizure free (ILAE Class 1 & 2) at one year. There was no statistically significant difference in seizure freedom outcomes in patients who had complete resection of atrophic posterior hippocampus or not (Fisher's Exact test statistic 0.69, not significant at p < .05) both at one year, and at last clinical follow-up. In the multivariate analysis only a history of status epilepticus (OR=0.2, 95%CI:0.042-0.955, p = .04) at one year, and pre-operative psychiatric disorder (OR=0.145, 95%CI:0.036-0.588, p = .007) at last clinical follow-up, were associated with a reduced chance of seizure freedom.

SIGNIFICANCE

Our data suggest that seizure freedom is not associated with whether or not posterior hippocampal atrophy is resected. This challenges the traditional surgical dogma of maximal posterior hippocampal resection in anteromesial temporal lobe resections and is a step further optimising this surgical procedure to maximise seizure freedom and minimise associated language and memory deficits.

Variations in the branching patterns of the anterior choroidal artery: an angiographic study with special reference to temporal lobe epilepsy surgery

BACKGROUND

The preservation of the anterior choroidal artery (AChA) is essential for avoiding neurological sequelae after mesial temporal lobe epilepsy (mTLE) surgery. The purpose of this study is to reveal the anatomical variation in which the perforating branches arise from the plexal segment of the AChA by using a modern neuroimaging modality.

METHODS

This study analyzed 3D rotational angiography (3DRA) images from 56 subjects. The AChA and perforating branches were visualized using slab MIP. We analyzed branching patterns, courses of the perforating arteries arising from the plexal segment of the AChA, and the anastomosis of the AChA with other cerebral arteries.

RESULTS

The slab MIP applied to 3DRA visualized one or more perforating branches from the AChA in 92.9% of cases. The presence of perforating branches arising from the AChA plexal segment was 17.3%. Most of the branching points of plexal perforators were likely located in the operative field during hippocampal resection. The course of the AChA plexal perforators included the posterior limb of the internal capsule. Anastomosis with other cerebral arteries was visualized in 25% of the AChA with plexal perforators.

CONCLUSIONS

3DRA slab MIP was useful for visualizing the perforating branches of the AChA. Our results showed the possibility that surgical manipulation of the choroid plexus may cause infarction in the AChA territory. We suggest that the existence of the AChA plexal perforators should be recognized to further enhance the safety of hippocampal resection for mTLE.

Multidisciplinary team meetings: the epilepsy experience

Multidisciplinary team (MDT) meetings are essential for ensuring optimal and consistent management for patients with complex problems and a variety of treatment options. Epilepsy surgery MDTs are a good example of complex decision making and planning to the best possible outcomes. The meetings need to run to an agreed format, with participants from neurology, neurophysiology, neuroimaging, neuropsychology, neuropsychiatry and neurosurgery all contributing succinct opinions to enable an informed discussion. A key feature of a successful MDT is to have a clear record of complementary data and perspectives, and to document management options. It is crucial to have a debrief after the event if an outcome is less good than anticipated, with the case being gone through in as much detail as a preoperative case, and ensuring that the whole team shares the successes and the disappointments and learns from the experience.

Severity Grading, Risk Factors, and Prediction Model of Complications After Epilepsy Surgery: A Large-Scale and Retrospective Study

Purpose: To report complications after epilepsy surgery, grade the severity of complications, investigate risk factors, and develop a nomogram for risk prediction of complications.

Methods: Patients with epilepsy surgery performed by a single surgeon at a single center between October 1, 2003 and April 30, 2019 were retrospectively analyzed. Study outcomes included severity grading of complications occurring during the 3-month period after surgery, risk factors, and a prediction model of these complications. Multivariable logistic regression analysis was used to calculate odds ratio and 95% confidence interval to identify risk factors.

Results: In total, 2,026 surgical procedures were eligible. There were 380 patients with mild complications, 23 with moderate complications, and 82 with severe complications. Being male (odds ratio 1.29, 95% confidence interval 1.02–1.64), age at surgery (>40 years: 2.58, 1.55–4.31; ≤ 40: 2.25, 1.39–3.65; ≤ 30: 1.83, 1.18–2.84; ≤ 20: 1.71, 1.11–2.63), intracranial hemorrhage in infancy (2.28, 1.14–4.57), serial number of surgery ( ≤ 1,000: 1.41, 1.01–1.97; ≤ 1,500: 1.63, 1.18–2.25), type of surgical procedure (extratemporal resections: 2.04, 1.55–2.70; extratemporal plus temporal resections: 2.56, 1.80–3.65), surgery duration (>6 h: 1.94, 1.25–3.00; ≤ 6: 1.92, 1.39–2.65), and acute postoperative seizure (1.44, 1.06–1.97) were independent risk factors of complications. A nomogram including age at surgery, type of surgical procedure, and surgery duration was developed to predict the probability of complications.

Conclusions: Although epilepsy surgery has a potential adverse effect on the patients, most complications are mild and severe complications are few. Risk factors should be considered during the perioperative period. Patients with the above risk factors should be closely monitored to identify and treat complications timely. The prediction model is very useful for surgeons to improve postoperative management.

The incidence of postoperative cerebrospinal fluid leakage after elective cranial surgery: a systematic review

Cerebrospinal fluid (CSF) leakage is a major complication after elective neurosurgical procedures. The aim of this systematic literature review is to summarize the incidence rates of postoperative cerebrospinal fluid leakage for neurosurgical procedures, classified by surgical approach. The Pubmed, Cochrane, Embase, and Web of Science databases were searched for studies reporting the outcome of patients undergoing elective neurosurgical procedures. The number of patients, surgical approach, and indication for surgery were recorded for each study. Outcomes related to CSF leakage such as clinical manifestation and treatment were reported as well. One hundred and thirteen studies were included, reporting 94,695 cases. Overall, CSF leaks were present in 3.8% of cases. Skull base surgery had the highest rate of CSF leakage with 6.2%. CSF leakage occurred in 5.9% of anterior skull base procedures, 6.4% of middle fossa, and 5.2% of transpetrosal surgeries. 5.8% of reported infratentorial procedures were complicated by CSF leakage versus 2.9% of supratentorial surgeries. CSF leakage remains a common serious adverse event after cranial surgery. There exists a need for standardized procedures to reduce the incidence of postoperative CSF leakage, as this serious adverse event may lead to increased health care costs.

Intraoperative overlay of optic radiation tractography during anteromesial temporal resection: a prospective validation study

OBJECTIVE

Anteromesial temporal lobe resection (ATLR) results in long-term seizure freedom in patients with drug-resistant focal mesial temporal lobe epilepsy (MTLE). There is significant anatomical variation in the anterior projection of the optic radiation (OR), known as Meyer's loop, between individuals and between hemispheres in the same individual. Damage to the OR results in contralateral superior temporal quadrantanopia that may preclude driving in 33%-66% of patients who achieve seizure freedom. Tractography of the OR has been shown to prevent visual field deficit (VFD) when surgery is performed in an interventional MRI (iMRI) suite. Because access to iMRI is limited at most centers, the authors investigated whether use of a neuronavigation system with a microscope overlay in a conventional theater is sufficient to prevent significant VFD during ATLR.

METHODS

Twenty patients with drug-resistant MTLE who underwent ATLR (9 underwent right-side ATLR, and 9 were male) were recruited to participate in this single-center prospective cohort study. Tractography of the OR was performed with preoperative 3-T multishell diffusion data that were overlaid onto the surgical field by using a conventional neuronavigation system linked to a surgical microscope. Phantom testing confirmed overlay projection errors of < 1 mm. VFD was quantified preoperatively and 3 to 12 months postoperatively by using Humphrey and Esterman perimetry.

RESULTS

Perimetry results were available for all patients postoperatively, but for only 11/20 (55%) patients preoperatively. In 1/20 (5%) patients, a significant VFD occurred that would prevent driving in the UK on the basis of the results on Esterman perimetry. The VFD was identified early in the series, despite the surgical approach not transgressing OR tractography, and was subsequently found to be due to retraction injury. Tractography was also used from this point onward to inform retractor placement, and no further significant VFDs occurred.

CONCLUSIONS

Use of OR tractography with overlay outside of an iMRI suite, with application of an appropriate error margin, can be used during approach to the temporal horn of the lateral ventricle and carries a 5% risk of VFD that is significant enough to preclude driving postoperatively. OR tractography can also be used to inform retractor placement. These results warrant a larger prospective comparative study of the use of OR tractography-guided mesial temporal resection.

Stereoelectroencephalography in epilepsy, cognitive neurophysiology, and psychiatric disease: safety, efficacy, and place in therapy

For patients with drug-resistant epilepsy, surgical intervention may be an effective treatment option if the epileptogenic zone (EZ) can be well localized. Subdural strip and grid electrode (SDE) implantations have long been used as the mainstay of intracranial seizure localization in the United States. Stereoelectroencephalography (SEEG) is an alternative approach in which depth electrodes are placed through percutaneous drill holes to stereotactically defined coordinates in the brain. Long used in certain centers in Europe, SEEG is gaining wider popularity in North America, bolstered by the advent of stereotactic robotic assistance and mounting evidence of safety, without the need for catheter-based angiography. Rates of clinically significant hemorrhage, infection, and other complications appear lower with SEEG than with SDE implants. SEEG also avoids unnecessary craniotomies when seizures are localized to unresectable eloquent cortex, found to be multifocal or nonfocal, or ultimately treated with stereotactic procedures such as laser interstitial thermal therapy (LITT), radiofrequency thermocoagulation (RF-TC), responsive neurostimulation (RNS), or deep brain stimulation (DBS). While SDE allows for excellent localization and functional mapping on the cortical surface, SEEG offers a less invasive option for sampling disparate brain areas, bilateral investigations, and deep or medial targets. SEEG has shown efficacy for seizure localization in the temporal lobe, the insula, lesional and nonlesional extra-temporal epilepsy, hypothalamic hamartomas, periventricular nodular heterotopias, and patients who have had prior craniotomies for resections or grids. SEEG offers a valuable opportunity for cognitive neurophysiology research and may have an important role in the study of dysfunctional networks in psychiatric disease and understanding the effects of neuromodulation.

Surgery in patients with childhood-onset epilepsy: analysis of complications and predictive risk factors for a severely complicated course

OBJECT

To compare the occurrence of surgery-related complications in patients with childhood-onset focal epilepsy operated on in the paediatric or in the adult age. To investigate risk factors for surgery-related complications in the whole cohort, with special attention to age at surgery and severe morbidity.

METHODS

A cohort of 1282 patients operated on for childhood-onset focal epilepsy was retrospectively analysed. Occurrence of surgery-related complications, including a severely complicated course (SCC: surgical complication requiring reoperation and/or permanent neurological deficit and/or death), was compared between patients operated on in the paediatric age (<16 year-old; 452 cases) and, respectively, in adulthood (≥16 year-old; 830 cases). The whole cohort of patients was also evaluated for risk factors for a SCC.

RESULTS

At last contact (median follow-up 98 months), 74.5% of patients were in Engel's class I (78.0% of children and 73.0% of adults). One hundred patients (7.8%) presented a SCC (6.4% for children and 8.6% for adult patients). Postoperative intracranial haemorrhages occurred more frequently in adult cases. At multivariate analysis, increasing age at operation, multilobar surgery, resections in the rolandic/perirolandic and in insulo-opercular regions were independent risk factors for a SCC.

CONCLUSIONS

Surgery for childhood-onset focal epilepsy provides excellent results on seizures and an acceptable safety profile at any age. Nevertheless, our results suggest that increasing age at surgery is associated with an increase in odds of developing severe surgery-related complications. These findings support the recommendation that children with drug-resistant, symptomatic (or presumed symptomatic) focal epilepsy should be referred for a surgical evaluation as early as possible after seizure onset.

Surgical and neurological complications in temporal lobe epilepsy surgery in modern era

Background

Temporal lobe epilepsy is the most common form of focal epilepsy, and surgical treatment has been proven to be an effective and safe management. Despite its safety, it is important to know that some complications and/or even death can be seen after surgery. Neurosurgeons should be able to precisely inform epilepsy surgery candidates about the possible unwanted/unexpected conditions after surgery.

Methods

Fifty-three patients who underwent anterior temporal lobe resection due to temporal lobe epilepsy by a single surgeon were investigated retrospectively regarding postoperative surgical and neurological complications.

Results

Overall complication rate was found to be 19%, surgical complications comprised 13.2% whereas neurological complications were 5.8%. Three patients underwent a second surgery whereas the rest had medical treatment or recovered spontaneously. Fortunately persistent complication rate was found to be 0%, and there was no mortality.

Conclusions

Anterior temporal lobe resection is a safe and very effective surgical modality for the treatment of temporal lobe epilepsy. However, unexpected complications may be possible in this modern era and a surgeon should trust in him/herself not in modern equipments.

Surgical versus medical treatment of drug-resistant epilepsy: A systematic review and meta-analysis

OBJECTIVE

Surgery and drug therapy are the two main treatments for refractory epilepsy. However, to date, there has not been an adequate comparison of the outcomes of these two treatments. This systematic review compared the overall outcome of surgery and medical treatment in patients with drug-resistant epilepsy.

METHODS

Articles published in Embase, Medline, Pubmed, and the Cochrane library were searched from their inception until June 2016.

RESULTS

Twenty of the eighty-one (24.7%) full-text articles reviewed fulfilled the eligibility criteria and were included in the meta-analysis. Of 1800 patients with drug-resistant epilepsy, 526 of 923 patients (57.0%) in the surgery group were seizure-free compared with 134 of 877 patients (15.3%) in the medical treatment group (19 studies, risk ratio (RR)=3.72, 95% confidence interval (CI) [2.75-5.03]; P<0.00001, I²=53%). In addition, more patients were off antiepileptic drugs (AEDs) in the surgical group (3 studies, n=438, RR=4.76, 95% CI [2.21, 10.28], P<0.0001, I²=0%). Although different studies used different questionnaires to assess patient quality of life (QOL) in both treatment groups, the overall postintervention QOL scores were higher in the surgery than in the medical treatment group, by SMD (6 studies, n=459, SMD=0.61, 95% CI [0.23, 0.98], P=0.002, I²=66%).

CONCLUSION

As the complications of interventions, declines in memory, and word recall/naming were not assessed in the meta-analysis, the conclusions are limited to seizure-free, AED use, and QOL. The current evidence indicate that compared with medical treatment, surgery is more likely to achieve seizure-free, off AEDs, and better QOL.

Getting the best outcomes from epilepsy surgery

Neurosurgery is an underutilized treatment that can potentially cure drug‐refractory epilepsy. Careful, multidisciplinary presurgical evaluation is vital for selecting patients and to ensure optimal outcomes. Advances in neuroimaging have improved diagnosis and guided surgical intervention. Invasive electroencephalography allows the evaluation of complex patients who would otherwise not be candidates for neurosurgery. We review the current state of the assessment and selection of patients and consider established and novel surgical procedures and associated outcome data. We aim to dispel myths that may inhibit physicians from referring and patients from considering neurosurgical intervention for drug‐refractory focal epilepsies. Ann Neurol 2018;83:676–690

The impact of epilepsy surgery on the structural connectome and its relation to outcome

Background

Temporal lobe surgical resection brings seizure remission in up to 80% of patients, with long-term complete seizure freedom in 41%. However, it is unclear how surgery impacts on the structural white matter network, and how the network changes relate to seizure outcome.

Methods

We used white matter fibre tractography on preoperative diffusion MRI to generate a structural white matter network, and postoperative T1-weighted MRI to retrospectively infer the impact of surgical resection on this network. We then applied graph theory and machine learning to investigate the properties of change between the preoperative and predicted postoperative networks.

Results

Temporal lobe surgery had a modest impact on global network efficiency, despite the disruption caused. This was due to alternative shortest paths in the network leading to widespread increases in betweenness centrality post-surgery. Measurements of network change could retrospectively predict seizure outcomes with 79% accuracy and 65% specificity, which is twice as high as the empirical distribution. Fifteen connections which changed due to surgery were identified as useful for prediction of outcome, eight of which connected to the ipsilateral temporal pole.

Conclusion

Our results suggest that the use of network change metrics may have clinical value for predicting seizure outcome. This approach could be used to prospectively predict outcomes given a suggested resection mask using preoperative data only.

Factors affecting seizure outcome after epilepsy surgery: an observational series

IMPORTANCE

Surgical treatment can bring seizure remission in people with focal epilepsy but requires careful selection of candidates.

OBJECTIVES

To determine which preoperative factors are associated with postoperative seizure outcome.

DESIGN

We audited seizure outcome of 693 adults who had resective epilepsy surgery between 1990 and 2010 and used survival analysis to detect preoperatively identifiable risk factors of poor seizure outcome.

RESULTS

Seven factors were significantly associated with increased probability of recurrence of seizures with impaired awareness postsurgery: MRI findings (eg, HR adjusted for other variables in the model 2.5; 95% CI 1.6 to 3.8 for normal MRI compared with hippocampal sclerosis), a history of secondarily generalised convulsive seizures (2.3; 95% CI 1.7 to 3.0 for these seizures in the previous year vs never), psychiatric history (1.3; 95% CI 1.1 to 1.7), learning disability (1.8; 95% CI 1.2 to 2.6) and extratemporal (vs temporal) surgery (1.4; 95% CI 1.02, 2.04). People with an older onset of epilepsy had a higher probability of seizure recurrence (1.01; 95% CI 1.00, 1.02) as did those who had used more antiepileptic drugs (1.05; 95% CI 1.01 to 1.09). Combinations of variables associated with seizure recurrence gave overall low probabilities of 5-year seizure freedom (eg, a normal MRI and convulsive seizures in the previous year has a probability of seizure freedom at 5 years of approximately 0.19).

CONCLUSIONS AND RELEVANCE

Readily identified clinical features and investigations are associated with reduced probability of good outcome and need consideration when planning presurgical evaluation.