Amygdalohippocampotomy: surgical technique and clinical results

Multiple hippocampal transection for mesial temporal lobe epilepsy: A systematic review

PURPOSE

Multiple hippocampal transection (MHT) is a surgical technique that offers adequate seizure control with minimal perioperative morbidity. However, there is little evidence available to guide neurosurgeons in selecting this technique for use in appropriate patients. This systematic review analyzes patient-level data associated with MHT for intractable epilepsy, focusing on postoperative seizure control and memory outcomes.

METHODS

The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant articles were identified from 3 databases (PubMed, Medline, Embase) up to August 1, 2021. Inclusion criteria were that the majority of patients had received a diagnosis of intractable epilepsy, the article was written in English, MHT was the primary procedure, and patient-level metadata were included.

RESULTS

Fifty-nine unique patients who underwent MHT were identified across 11 studies. Ten (17%) of 59 patients underwent MHT alone. Forty-three (75%) of 57 patients who had a follow-up 12 months or longer were seizure free at last follow-up. With respect to postoperative verbal memory retention, 9 of 38 (24%) patient test scores did not change, 14 (37%) decreased, and 16 (42%) increased. With respect to postoperative nonverbal memory retention, 12 of 38 (34%) patient test scores did not change, 13 (34%) decreased, and 13 (33%) increased.

CONCLUSION

There are few reported patients analyzed after MHT. Although the neurocognitive benefits of MHT are unproven, this relatively novel technique has shown promise in the management of seizures in patients with intractable epilepsy. However, structured trials assessing MHT in isolation are warranted.

Clinical outcome of selective amygdalectomy in a series of patients with resistant temporal lobe epilepsy

Background:

Selective amygdalohippocampectomy is one of the main approaches for treating medial temporal lobe epilepsy (TLE). We herewith describe seven cases of amygdala lesions treated with selective amygdalectomy with the hippocampus saving procedure. Furthermore, we explain the trans-middle temporal gyrus transventricular approach for selective amygdalectomy.

Methods:

We studied patients with TLE who underwent selective amygdalectomy with hippocampal saving procedure between March 2012 and July 2018. We preferred the trans-middle temporal gyrus transventricular approach. We adopted pterional craniotomy with extensive exposure of the base and posterior of the temporal lobe. The posterior margin of resection in the intraventricular part of the amygdala was considered the inferior choroidal point. Medially anterior part of the uncus was resected until reaching the ambient cistern. We applied the transcortical transventricular approach for selective amygdalectomy in all patients.

Results:

We present 11 cases having an amygdala lesion in our series, seven of whom underwent selective amygdalectomy with hippocampal sparing. Nine patients had neoplastic lesions, and in two of them, gliosis was evident. Total resection of the lesion was achieved in all cases based on postoperative magnetic resonance imaging. No unusual complication or surgically-related new neurological deficit occurred.

Conclusion:

We consider the resection of the amygdala until the inferior choroidal point sufficient for the disconnection of its circuits, which results in more effective control of seizures and reduction of surgery time and complications.

The impact of sub specialization within functional neurosurgery on patient outcomes in a comprehensive epilepsy center

BACKGROUND

One in three patients with epilepsy are medication-refractory and may benefit from investigations and operative treatment at a comprehensive epilepsy center. However, while these centers have capabilities for advanced seizure monitoring and surgical intervention, they are not required to have a functional neurosurgeon who is primarily focused in epilepsy surgery. Therefore, the objective of this study is to determine the impact of having a sub-specialized, epilepsy-focused functional neurosurgeon on patient outcomes.

METHODS

We conducted a retrospective chart review for all patients who underwent surgical intervention for medically refractory epilepsy at a Level 4 comprehensive Epilepsy Center from 2008 through 2019. Data was divided into two groups: group 1 comprised patients who had surgery before the hiring of a dedicated epilepsy-focused functional neurosurgeon in 2016, and group 2 was afterwards. We compared surgical procedures, significant complications, and seizure outcomes.

RESULTS

A total of 101 patients underwent 105 operations (52 in group 1 and 53 in group 2), not including intracranial EEG insertion. Compared to group 1, group 2 had more surgeries performed per year (15.1 vs. 6.5), and a significantly lower Engel score at last follow-up (1.78 vs. 2.57; p < 0.001). There was no difference in percentage of cases undergoing iEEG, and no difference in complication rates.

CONCLUSIONS

In this series, the hiring of a sub-specialized functional neurosurgeon dedicated to epilepsy surgery in a comprehensive epilepsy center was associated with an increase in surgical volume and improved seizure outcomes.

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.

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.

Rates and predictors of seizure freedom in resective epilepsy surgery: an update

Epilepsy is a debilitating neurological disorder affecting approximately 1 % of the world's population. Drug-resistant focal epilepsies are potentially surgically remediable. Although epilepsy surgery is dramatically underutilized among medically refractory patients, there is an expanding collection of evidence supporting its efficacy which may soon compel a paradigm shift. Of note is that a recent randomized controlled trial demonstrated that early resection leads to considerably better seizure outcomes than continued medical therapy in patients with pharmacoresistant temporal lobe epilepsy. In the present review, we provide a timely update of seizure freedom rates and predictors in resective epilepsy surgery, organized by the distinct pathological entities most commonly observed. Class I evidence, meta-analyses, and individual observational case series are considered, including the experiences of both our institution and others. Overall, resective epilepsy surgery leads to seizure freedom in approximately two thirds of patients with intractable temporal lobe epilepsy and about one half of individuals with focal neocortical epilepsy, although only the former observation is supported by class I evidence. Two common modifiable predictors of postoperative seizure freedom are early operative intervention and, in the case of a discrete lesion, gross total resection. Evidence-based practice guidelines recommend that epilepsy patients who continue to have seizures after trialing two or more medication regimens should be referred to a comprehensive epilepsy center for multidisciplinary evaluation, including surgical consideration.