TEMPORAL LOBOTOMY IN THE SURGICAL MANAGEMENT OF EPILEPSY: TECHNICAL REPORT

Immediate neural impact and incomplete compensation after semantic hub disconnection

The human brain extracts meaning using an extensive neural system for semantic knowledge. Whether broadly distributed systems depend on or can compensate after losing a highly interconnected hub is controversial. We report intracranial recordings from two patients during a speech prediction task, obtained minutes before and after neurosurgical treatment requiring disconnection of the left anterior temporal lobe (ATL), a candidate semantic knowledge hub. Informed by modern diaschisis and predictive coding frameworks, we tested hypotheses ranging from solely neural network disruption to complete compensation by the indirectly affected language-related and speech-processing sites. Immediately after ATL disconnection, we observed neurophysiological alterations in the recorded frontal and auditory sites, providing direct evidence for the importance of the ATL as a semantic hub. We also obtained evidence for rapid, albeit incomplete, attempts at neural network compensation, with neural impact largely in the forms stipulated by the predictive coding framework, in specificity, and the modern diaschisis framework, more generally. The overall results validate these frameworks and reveal an immediate impact and capability of the human brain to adjust after losing a brain hub.

Functional Anterior Temporal Lobectomy for Temporal Lobe Epilepsy: A Novel, Alternative, and Less Invasive Therapy

BACKGROUND

Anterior temporal lobectomy is the most effective treatment for intractable temporal lobe epilepsy (TLE). However, patients are reluctant to choose this surgery for fear of risks after large frontotemporal craniotomy, and epileptologists likewise have a cautious attitude because of surgical trauma. Functional anterior temporal lobectomy (FATL) is a minimally invasive surgery procedure for addressing the above concerns.

OBJECTIVE

To report preliminary data on this procedure and its safety and efficacy for treating TLE.

METHODS

This consecutive case series study was conducted between October 2020 and September 2021. Patients with TLE underwent FATL by minicraniotomy with a diameter of 3 cm. Surgery duration, postoperative complications, and seizure control are described herein. Seizure outcomes were classified using Engel classifications.

RESULTS

A total of 25 patients undergoing FATL for TLE were enrolled. The median epilepsy duration was 8 years. The median surgery duration was 165 min. The median blood loss was 100 mL. The median postoperative hospital stay was 8 days. No deaths occurred after surgery. Only 1 patient presented with a cerebrospinal fluid disorder that was successfully treated using a ventriculoperitoneal shunt. At the last follow-up, 23 patients (92%) were seizure-free (Engel-Ia), 1 patient remained substantially improved (Engel-II), and 1 patient obtained worthwhile seizure reduction (Engel-III).

CONCLUSION

Our pilot study suggests that FATL is a viable surgical therapy for TLE. This method has the advantages of minimal invasiveness and high seizure-free rate. A controlled trial is warranted to verify the efficacy and safety of FATL comparing with anterior temporal lobectomy.

Epilepsy surgery in children: what the radiologist needs to know

This review updates the radiologist on current epilepsy surgery practice in children, with a specific focus on the role of imaging in pre-surgical work-up, current and novel surgical techniques, expected post-surgical imaging appearances and important post-operative complications. A comprehensive review of the current and emerging international practices in paediatric epilepsy surgical planning and post-operative imaging is provided with details on case-based radiological findings. A detailed discussion of the pathophysiology and imaging features of different epileptogenic lesions will not be discussed as this is not the objective of this paper. Epilepsy surgery can be an effective method to control seizures in certain children with drug-resistant focal epilepsy. Early surgery in selected appropriate cases can lead to improved cognitive and developmental outcome. Advances in neurosurgical techniques, imaging and neuroanaesthesia have driven a parallel expansion in the array of epilepsy conditions which are potentially treatable with surgery. The range of surgical options is now wide, including minimally invasive ablative procedures for small lesions such as hypothalamic hamartomata, resections for focal lesions like hippocampal sclerosis and complex disconnective surgeries for multilobar conditions like Sturge Weber Syndrome and diffuse cortical malformations. An awareness of the surgical thinking when planning epilepsy surgery in children, and the practical knowledge of the operative steps involved will promote more accurate radiology reporting of the post-operative scan.

Comparison of seizure outcomes and safety between anterior temporal lobotomy and lobectomy in patients with temporal lobe epilepsy

Objectives: To compare the efficacy and safety of anterior temporal lobotomy (ATLo) and anterior temporal lobectomy (ATLe) in drug-resistant temporal lobe epilepsy.Methods: Patients diagnosed with pharmacoresistant temporal lobe epilepsy who underwent anterior temporal lobotomy (ATLo) or anterior temporal lobectomy (ATLe) performed by a single surgeon were retrospectively included. Every patient was followed up annually after surgery. The postoperative seizure outcome evaluation was based on the Engel and ILAE classifications. We compared postoperative complications and 2-year follow-up seizure outcomes between the ATLo group and the ATL group.Results: A total of 42 individuals (21 ATLo and 20 ATLe) were included. At the two-year follow-up, more patients in the ATLo group than the ATLe group had reached Engel class I (20 versus 14) and ILAE I (19 versus 13). However, these differences were not significant. One patient in the ATLo group had intraparenchymal hematoma and fully recovered. The two groups had similar incidences of other short-term complications, and no patients died or had any permanent complications.Discussion: ATLo is not inferior to ATLe for patients with drug-resistant temporal epilepsy. There was no significant difference in seizure outcomes or the rate of postoperative complications between the two groups. A large sample randomized control study is needed.

Neurosurgical approaches to pediatric epilepsy: Indications, techniques, and outcomes of common surgical procedures

Epilepsy is a common pediatric neurological condition, and approximately one-third of children with epilepsy are refractory to medical management. For these children neurosurgery may be indicated, but operative success is dependent on complete delineation of the epileptogenic zone. In this review, surgical techniques for pediatric epilepsy are considered. First, potentially-curative operations are discussed and broadly divided into resections and disconnections. Then, two palliative approaches to seizure control are reviewed. Finally, future neurosurgical approaches to epilepsy are considered.

Amygdalohippocampotomy for mesial temporal lobe sclerosis: Epilepsy outcome 5 years after surgery

BACKGROUND

The goal of the present study is the evaluation of the long-term clinical outcome of epilepsy in patients with mesial temporal lobe sclerosis (MTLS) submitted to amygdalohippocampotomy (AHCo). AHCo consists of the lateral ablation of the amygdala and the peri-hippocampal disconnection instead of amygdalohippocampectomy (AHC), which involves the removal of both structures. We previously reported the short-term results of AHCo, so we here present the long-term results (> 5 years of follow-up) of the patients operated on with AHCo.

METHOD

Since 2007, 35 patients (22 females) aged 20-61 years (mean: 42 years) were operated on with the AHCo technique, 17 patients on the left side and 18 on the right. Of these patients, 21 (14 females) have been followed up > 5 years (5 to 7.5 years, mean 6.5 years). We compare the present results with those observed shortly after surgery and with the patients operated on with AHC.

FINDINGS

In all 21 cases, the diagnosis was mesial temporal lobe sclerosis (histology confirmed in 20), 11 on the left side and 10 on the right. Epilepsy results after 5 years were good/very good in 18 patients (85.7%), with Engel class IA-B in 15 (71.4%) and II in 3 (14.3%), and bad in 3 patients, with Engel Class III in 2 (9.5%) and class IV in 1 (4.8%). Concerning morbidity, one patient had hemiparesis (hypertensive capsular hemorrhage 24 h after surgery), two verbal memory worsening, two quadrantanopia and three late depression that was reversed with medication. Comparatively, the AHC long-term results were 87% Engel class I, 8% Engel class II and 5% Engel class III-IV. The morbidity was equally small.

CONCLUSIONS

The good/very good results of AHCo 5 years after surgery are 86%, which is not distinct from the AHC results. So AHCo seems to be effective and potentially safer than AHC in long-term follow-up.

New endoscopic route to the temporal horn of the lateral ventricle: surgical simulation and morphometric assessment

Object

The temporal horn of the lateral ventricle is a complex structure affected by specific pathological conditions. Current approaches to the temporal horn involve a certain amount of corticotomy and white matter disruption. Surgeons therefore set aside anterior temporal lobectomy as a last resource and avoid it in the dominant hemisphere. The authors propose a minimally invasive endoscopic intraventricular approach to the temporal horn and describe a standardized analysis and technical assessment of the feasibility of this approach.

Methods

To determine the best trajectory, angulation, and entry point to the temporal horn of the lateral ventricle, the authors evaluated 50 cranial MRI studies (100 temporal lobes) from healthy patients. They studied and systematized the neurosurgical endoscopic anatomy. They also simulated the proposed approach in 9 cadaveric specimens (18 approaches).

Results

Mean scalp entry point coordinates (± SD) were 2.7 ± 0.28 cm lateral to the inion and 5.6 ± 0.41 cm superior to the inion. The mean total distance from the uncal recess to the scalp (± SD) was 10.64 ± 0.6 cm. The mean total intraparenchymal distance crossed by the endoscope was 3.76 ± 0.36 cm. The approach was successfully completed in all studied specimens.

Conclusions

In this study, the endoscopic intraventricular approach to the temporal horn is standardized. The morphometric analysis makes this approach anatomically feasible and replicable. This approach provides minimally invasive endoscopic access to the uncal recess, amygdala, hippocampus, fornix, and paraventricular temporal lobe structures. The following essential strategies enabled access to and maneuverability inside the temporal horn: tailored preoperative planning of the trajectory and use of anatomical and radiological references, constant irrigation, and an angled endoscopic lens. Safety assessment and novel instruments and techniques may be proposed to advance this very promising route to pathological changes in the temporal lobe.

Long-term outcome of surgical disconnection of the epileptic zone as an alternative to resection for nonlesional mesial temporal epilepsy

BACKGROUND

Pharmacoresistant epilepsy can be treated by either resection of the epileptic focus or functional isolation of the epileptic focus through complete disconnection of the pathways of propagation of the epileptic activity.

OBJECTIVE

To evaluate long-term seizure outcome and complications of temporal lobe disconnection (TLD) without resection for mesial temporal lobe epilepsy (MTLE).

METHODS

Data of 45 patients operated on for intractable MTLE using a functional disconnection procedure have been studied. Indication of TLD surgery was retained after a standard preoperative evaluation of refractory epilepsy and using the same criteria as for standard temporal resection.

RESULTS

Mean follow-up duration was 3.7 years. At the last follow-up, 30 patients (67%) were completely seizure-free (Engel-Ia/International League Against Epilepsy class 1) and 39 patients (87%) remained significantly improved (Engel-I or -II) by surgery. Actuarial outcome displays a 77.7% probability of being seizure-free and an 85.4% probability of being significantly improved at 5 years. No patient died after surgery and no subdural haematoma or hygroma occurred. Permanent morbidity included hemiparesis, hemianopia and oculomotor paresis found in three, five and one patient, respectively, after TLD.

CONCLUSIONS

TLD is acceptable alternative surgical technique for patients with intractable MTLE. The results of TLD are in the range of morbidity and long-term seizure outcome rates after standard surgical resection. We observed a slightly higher rate of complications after TLD in comparison with usual rates of morbidity of resection procedures. TLD may be used as an alternative to resection and could reduce operating time and the risks of subdural collections.

Pediatric temporal lobe epilepsy surgery: resection based on etiology and anatomical location

Advances in electrophysiological assessment with improved structural and functional neuroimaging have been very helpful in the use of surgery as a tool for drug-resistant epilepsy. Increasing interest in epilepsy surgery has had a major impact on adult patients; a refined evaluation process and new criteria for drug resistance combined with refined surgical techniques resulted in large surgical series in many centers. Pediatric surgery has lagged behind this evolution, possibly because of the diverse semiology and electrophysiology of pediatric epilepsy obscuring the focal nature of the seizures and frustrating the treatment of catastrophic epileptic syndromes specific to children. Unfortunately, refractory -epilepsy is more -devastating in children than in adults as it interferes with all aspects of neural development. Nevertheless, during the last few decades, the efforts of a small number of centers with encouraging results in pediatric epilepsy surgery have motivated pediatric neurologists to gain interest. Although well behind in the number of patients compared with that of adults, pediatric series are increasing exponentially. While temporal lobe epilepsy is the focus of interest in adults, with almost 70 % of resections in the temporal lobe, the pediatric epilepsy spectrum is different. Resective or functional surgery techniques devoted to resistant extratemporal epilepsy are the major improvements in pediatric epilepsy surgery. Temporal lobe epilepsy in adults has been studied extensively but only recently has begun to receive attention in children. Several aspects of temporal lobe epilepsy in childhood remain unclear or controversial in terms of seizure semiology and its pathology. This is reflected in the surgical treatment. Information on the major contributors to a favorable outcome, such as type or extent of resection, in terms of seizure control and morbidity is not available as in adult temporal lobe epilepsy. This chapter discusses the major discrepancies between adult and pediatric temporal lobe epilepsy and outlines the current concepts in surgical treatment. The resection strategy based on the different substrates at different locations in the temporal lobe causing seizures is emphasized with respect to available literature.

Trephine Epilepsy Surgery: The Inferior Temporal Gyrus Approach

Objective:

To describe our technique for temporal lobe epilepsy surgery using a minimal-access approach.

Methods:

Our epilepsy surgery registry was reviewed, and all patients with at least 2 years follow-up were queried. Clinical data included age, sex, side of lesion, presence of mesial temporal sclerosis, surgical complications, and Engel class outcome. Our operation was performed through a 6- to 8-cm linear vertical incision extending upward from just anterior to the tragus. An oval trephine (2×3 cm) craniotomy was performed flush with the middle fossa floor. Resection of part of the inferior temporal gyrus provided a corridor to the mesial temporal lobe. Identification of the temporal horn of the lateral ventricle was followed by resection of the parahippocampal gyrus, the amygdala, and the uncus. Segregation of the hippocampus and its subsequent resection in subpial fashion preserved perimesencephalic vasculature. Use of a fine suture for skin closure produced a cosmetic result.

Results:

In our 8-year series of 201 patients with a minimum follow-up duration of 2 years, we have observed a low number (1.5%) of complications and a 78% rate of Engel Class I seizure-free outcome. Surgery times were short (average, 2–5 h; range, 2 h 20 min-4 h 10 min) and hospital stays brief (<3 d; range, 1–4 d).

Conclusion:

Our results suggest that the trephine craniotomy with the inferior temporal gyrus approach has the advantage of minimal invasiveness, including brief operative times and postoperative stays, and also effectively reduces or eradicates medically intractable seizures.