Corpus callosotomy (CC) is appropriate for patients with seizures of a bilateral or diffuse origin, or those with seizures of a unilateral origin with rapid spread to the contralateral cerebral hemisphere. The efficiency of CC in patients with drug-resistant epilepsy is a long-term concern because most articles reporting the surgical results of CC arise from small case series, and the durations of follow-up vary.
PubMed, Embase, Cochrane Library, and Web of Science were searched to identify papers published before November 8, 2021. The systematic review was completed following PRISMA guidelines. Outcomes were analyzed by meta-analysis of the proportions.
A total of 1644 patients with drug-resistant epilepsy (49 retrospective or prospective case series studies) underwent CC, and the follow-up time of all patients was at least 1 year. The rate of complete seizure freedom (SF) was 12.38% (95% confidence interval [CI], 8.17%-17.21%). Meanwhile, the rate of complete SF from drop attacks was 61.86% (95% CI, 51.87%-71.41%). The rates of complete SF after total corpus callosotomy (TCC) and anterior corpus callosotomy (ACC) were 11.41% (95% CI, 5.33%-18.91%) and 6.75% (95% CI, 2.76%-11.85%), respectively. Additionally, the rate of complete SF from drop attacks after TCC was significantly higher than that after ACC (71.52%, 95% CI, 54.22%-86.35% vs. 57.11%, 95% CI, 42.17%-71.49%). The quality of evidence for the three outcomes by GRADE assessment was low to moderate.
There was no significant difference in the rate of complete SF between TCC and ACC. TCC had a significantly higher rate of complete SF from drop attacks than did ACC. Furthermore, CC for the treatment of drug-resistant epilepsy remains an important problem for further investigation because there are no universally accepted standardized guidelines for the extent of CC and its benefit to patients. In future research, we will focus on this issue.

UNASSIGNED: There is a growing body of literature suggesting that the corpus callosum plays an important role in behavior. While behavioral deficits are a rare complication following callosotomy, they are well-documented in agenesis of the corpus callosum (AgCC), with emerging evidence reporting disinhibition among children with AgCC.
UNASSIGNED: A 15-year-old girl had undergone a right frontal craniotomy and excision of a third ventricle colloid cyst using the transcallosal approach. Ten days after the operation, she was readmitted for progressive symptoms of behavioral disinhibition. Postoperative magnetic resonance imaging of the brain showed mild-to-moderate bilateral edematous changes along the operative bed, with no other significant findings.
UNASSIGNED: To the best of the authors\' knowledge, this is the first report in literature to describe behavioral disinhibition occurring as a sequelae to a surgical procedure involving callosotomy.

Both corpus callosotomy (CC) and the ketogenic diet (KD) are commonly used in patients with Lennox Gastaut syndrome (LGS), as a significant proportion of these patients develop pharmacoresistant epilepsy. But no systematic review has yet compared the efficacy and safety of these two measures.
We conducted a systematic search on various databases to collating all available literature until 30th November 2020 with a primary objective to compare the efficacy of KD and CC in terms of the proportion of patients with complete seizure freedom, at least 75% and 50% reduction in seizure frequency at various time points after the institution of these modalities. We also attempted to compare the proportion and nature of adverse effects, impact on EEG, cognition, and behavior with these modalities. We only included original articles enrolling at least 10 patients with CC or KD for quantitative synthesis to determine a pooled estimate. We used a fixed or random effects model, depending on the degree of heterogeneity.
We selected 23 and 7 articles describing the efficacy of CC and KD in 436 and 185 LGS patients out of 217 search items, but none of the studies compared directly these two entities. The indirect comparison between the pooled estimate of all patients with individual modalities revealed more patients with CC had seizure freedom, at least 75% and 50% reduction in seizure frequency (p=0.0001, 0.01, and 0.04 respectively). The proportion of patients with adverse effects was also higher for CC patients (p=0.01), although the proportion with serious adverse effects was not significantly different between the two modalities. Patients selected for CC were older, had higher seizure burden, more lag time after the onset of seizures, and received more number of antiseizure medications previously. Due to the availability of limited data, a firm conclusion could not be determined regarding the effect on EEG, cognition, and behavior with CC and KD.
CC is more efficacious than KD in reducing seizure frequency in patients with LGS, although it has relatively more adverse effects during the immediate perioperative period.

Lennox-Gastaut syndrome (LGS) is a severe form of childhood onset epilepsy in which patients require multiple medications and may be candidates for palliative surgical intervention. In this meta-analysis, we sought to evaluate the impact of palliative vagus nerve stimulation (VNS), corpus callosotomy (CC), and resective surgery (RS) by analyzing their impact on seizure control, antiepileptic drug (AED) usage, quality of life (QOL), behavior, cognition, prognostic factors, and complications. A systematic search of PubMed MEDLINE, Scopus, and Cochrane Database of Systematic Reviews was performed to find articles that met the following criteria: (1) prospective/retrospective study with original data, (2) at least one LGS surgery patient aged less than 18 years, and (3) information on seizure frequency reduction (measured as percentage, Engel class, or qualitative comment). Seizures were analyzed quantitatively in a meta-analysis of proportions and a random-effects model, whereas other outcomes were analyzed qualitatively. Forty studies with 892 LGS patients met the selection criteria, with 19 reporting on CC, 17 on VNS, four on RS, two on RS + CC, one on CC + VNS, and one on deep brain stimulation. CC seizure reduction rate was 74.1% (95% confidence interval [CI] = 64.5%-83.7%), and VNS was 54.6% (95% CI = 42.9%-66.3%), which was significantly different (p < .001). RS seizure reduction was 88.9% (95% CI = 66.1%-99.7%). Many VNS patients reported alertness improvements, and most had no major complications. VNS was most effective for atonic/tonic seizures; higher stimulation settings correlated with better outcomes. CC patients reported moderate cognitive and QOL improvements; disconnection syndrome, transient weakness, and respiratory complications were noted. Greater callosotomy extent correlated with better outcomes. AED usage most often did not change after surgery. RS showed considerable QOL improvements for patients with localized seizure foci. In the reported literature, CC appeared to be more effective than VNS for seizure reduction. VNS may provide a similar or higher level of QOL improvement with lower aggregate risk of complications. Patient selection, anatomy, and seizure type will inform decision-making.

Hypothalamic hamartomas (HH) are rare, non-neoplastic heterotopic tissues which contains normal neurons and glia including oligodendrocytes and fibrillary astrocytes but in an abnormal distribution. They arise from the floor of the third ventricle, tuber cinereum, or mammillary bodies. Estimated incidence ranges from 1 in 50,000 to 1 in 1,000,000. Hypothalamic hamartomas are associated with different clinical presentations including various types of seizures, most characteristically; the gelastic seizures, precocious puberty, cognitive impairment and behavioral changes. In this review, the authors discuss the recent advancements in the medical and surgical management of hypothalamic hamartoma that have been achieved over the past few decades. This review also discusses the advantages and disadvantages of each surgical line of management and factors determining the best individualized approach.

Aicardi syndrome is a severe neurodevelopmental disorder that occurs primarily in females and is characterized by seizures, agenesis of the corpus callosum, and chorioretinal lacunae, which occur together in the majority of affected individuals. Seizures begin in infancy and tend to progress in intensity and are often refractory to standard multimodal medication treatments.
We present here a unique case of a 12-year-old girl with partial agenesis of the corpus callosum who underwent a corpus callosotomy for treatment of medically refractory epilepsy. In so doing, we also review the literature with regard to the neurosurgical management of these unique patients.
For the subset of children who present with partial, rather than complete, agenesis of the corpus callosum, corpus callosotomy should be considered as a treatment option to reduce seizure burden.

The aim of this study was to evaluate postoperative seizure outcome in children with drug-resistant epilepsy not eligible for focal resection who underwent corpus callosotomy.
The study included 16 patients undergoing corpus callosotomy between September 2015 and May 2018. Seizure semiology and frequency, psychomotor status, and video electroencephalography and imaging findings were evaluated for all patients.
Of the 16 patients who underwent callosotomy during the study period, 11 underwent complete callosotomy and 5 underwent anterior only. Seizure improvement greater than 75% was achieved in 37.5% of patients, and another 50% of patients had seizure improvement of 50%-75%. No sustained neurological deficits were observed in these patients. There were no significant complications. Duration of postoperative follow-up ranged from 12 to 44 months.
Corpus callosotomy is an effective treatment for selected patients with drug-resistant epilepsy not eligible for focal resection in resource-limited settings. Fostering and developing international epilepsy surgery centers should remain a high priority for the neurosurgical community at large.

OBJECTIVE: Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy (SMEI), is a rare genetic disorder that results in severe childhood-onset epilepsy. Children with DS initially present with seizures in the first year of life that are often associated with fevers. With age, multiple seizure types develop. There are few reports and no guidelines regarding palliative surgical treatment for DS. Therefore, we reviewed our surgical experience with DS.
METHODS: We conducted a retrospective review of all patients with genetically confirmed DS who underwent either vagal nerve stimulator (VNS) implantation or corpus callosotomy (CC) from May 2001 to April 2014 at our institution. All inpatient and outpatient relevant documentation were reviewed. Demographic information, genetic mutation, operation performed, and preoperative and postoperative seizure frequency were recorded. Inclusion criteria required greater than one-year postoperative follow-up.
RESULTS: Seven children with DS were assessed. Six patients were treated with VNS and one patient was treated with CC. In one child, VNS was followed by CC as a secondary procedure. Therefore, in total, eight surgeries were performed on seven patients during the study period. At least 1 year elapsed from presentation to our hospital and surgery for all patients. Average time after the first seizure to VNS was 4.1 years, and the average time after the first seizure to CC was 7.6 years. The mean age of patients undergoing VNS implantation was 4.3 years, and the mean age for patients undergoing CC was eight. Average follow-up for all seven patients was 6.6 years. Seizures were decreased in five of the six patients with VNS and decreased in the two patients after CC. Four of the six patients who had VNS implanted had a greater than 50 % reduction in seizure frequency, and one of the six patients who had VNS implanted had a less than 50 % reduction in seizure frequency. One patient did not respond effectively to the VNS and had very limited change in seizure frequency. Both patients who had a CC had a greater than 50 % reduction in seizure frequency.
CONCLUSIONS: Both VNS and CC in patients with DS can be effective at reducing seizure frequency. Patients with DS may benefit from earlier and more aggressive surgical intervention. Studies using larger patient cohorts will help clarify the role that surgery may play in the multidisciplinary approach to controlling seizures in DS. Further studies will help determine the appropriate timing of and type of surgical intervention.

Corpus callosotomy is a palliative neurosurgical treatment for patients with either generalized or multifocal refractory epilepsy and injurious drop attacks. This report aims to systematically review the pediatric literature.
Medline, Embase, Web of Knowledge, and Scopus were searched systematically for published articles on treatment outcomes of corpus callosotomy for refractory epilepsy. Studies were included if the patient population was younger than 18 at the time of surgery and median follow-up was >1 year. Studies were excluded if resective surgery was also performed.
A total of 12 articles met inclusion criteria. All articles were retrospective case series, with the exception of one being a prospectively designed retrospective case series. There was very little agreement among authors on the definition of a good seizure outcome. Articles that used the Engel classification found that 88.2% of total corpus callosotomy patients had a worthwhile reduction in seizures compared with 58.6% of patients who underwent anterior corpus callosotomy (p < 0.05). Drop attacks improved from corpus callosotomy more than other generalized seizure types. Reported complications were minor in all but one patient, and one death was reported. Transient disconnection syndrome was significantly more likely in total corpus callosotomy than in anterior corpus callosotomy (12.5% vs. 0%; p < 0.05). Improvements in quality of life, behavior, and intelligence/development quotient, as well as parental satisfaction, were generally correlated with seizure outcome. There was no postcallosotomy change in the number of antiepileptic drugs.
Total corpus callosotomy was significantly more likely to result in a reduction in seizures. Anterior corpus callosotomy was unlikely to result in disconnection syndrome. Although all of the papers drew a similar conclusion, the quality of evidence was low. At best, the evidence raises the hypothesis that corpus callosotomy is a safe and effective treatment for refractory generalized epilepsy. It is clear that a case-control or randomized trial is warranted.

Atonic seizures are debilitating and poorly controlled with antiepileptic medications. Two surgical options are primarily used to treat medically refractory atonic seizures: corpus callosotomy (CC) and vagus nerve stimulation (VNS). However, given the uncertainty regarding relative efficacy and surgical complications, the best approach for affected patients is unclear. The PubMed database was queried for all articles describing the treatment of atonic seizures and drop attacks with either corpus callosotomy or VNS. Rates of seizure freedom, >50% reduction in seizure frequency, and complications were compared across the two patient groups. Patients were significantly more likely to achieve a >50% reduction in seizure frequency with CC versus VNS (85.6% versus 57.6%; RR: 1.5; 95% CI: 1.1-2.1). Adverse events were more common with VNS, though typically mild (e.g., 22% hoarseness and voice changes), compared with CC, where the most common complication was the disconnection syndrome (13.2%). Both CC and VNS are well tolerated for the treatment of refractory atonic seizures. Existing studies suggest that CC is potentially more effective than VNS in reducing seizure frequency, though a direct study comparing these techniques is required before a definitive conclusion can be reached.