Authors :
Presenting Author: Shravan Thaploo, BS – UCI
Alexander Himstead, MD – UCI
Bryce picton, BS – UCI
Samir Alsalek, BS – Kaiser Permanente
Jordan Davies, MD – UCI
Joffre Oyala, MD – Childrens Hospital of Orange County
Sumeet Vadera, MD – UC Irvine Medical Center
Rationale:
Surgical resection of the epileptogenic focus in patients with medically-refractory epilepsy frequently yields seizure freedom. However, the treatment options for patients with generalized or poorly localized refractory epilepsy is far more limited. As a palliative procedure, corpus callosotomy can reduce seizure burden by preventing seizure propagation across the corpus callosum, traditionally targeted to decrease drop attacks. While its efficacy is well established in the pediatric population, evidence supporting its effectiveness in adults remains limited. We performed the first systematic review of all reported adult corpus callosotomy cases and present a case series of adults who underwent corpus callosotomy for refractory, poorly-localized epilepsy at our institution.
Methods:
Primary studies published over the past 35 years were queried for seizure outcomes in patients ≥18 years of age after corpus callosotomy. Multiple variables, including age, seizure etiology, semiology, complications, and rates of seizure freedom were recorded. Preliminary analysis determined variables that demonstrated a potential relationship to seizure outcome. Additionally, after IRB approval, operative records of two surgeons from 2014 to 2025 were searched for individuals ≥18 years of age with refractory epilepsy treated with corpus callosotomy.Results:
The authors identified 254 eligible patients from 46 included studies in the systematic review and meta-analysis. As expected, median seizure reduction for atonic/drop seizures (51.5% with seizure freedom, 87.7% with >50% seizure reduction) was greater than all other seizure semiologies (p < 0.0001). However, there was meaningful seizure reduction in myoclonic (45% with seizure freedom, 70% with >50% seizure reduction) and tonic (28.3% with seizure freedom, 77.5% with >50% seizure reduction) semiologies. Unsurprisingly, we found that seizure reduction for simple seizures (2.94% with seizure freedom, 47.1% with > 50% seizure freedom) was significantly lower compared to all other seizure semiologies (p < 0.0001). Serious complications were rare with the most common complication being transient disconnection syndrome. Our findings suggest patients with Lennox Gastaut Syndrome (LGS) tended to have a larger median seizure reduction compared to all other seizure etiologies (p = 0.0055). The twenty-two patients in our case series also had positive outcomes, reflecting the results seen in the systematic review. Almost all patients reported >80% reduction in seizure frequency at 3 months post-op, with notable seizure reductions seen in atonic seizures and patients with LGS.Conclusions:
Few studies focus on seizure types and outcomes of corpus callosotomy in adult patients alone. As expected, the greatest seizure reductions were seen in atonic seizures, however, other seizure types had meaningful decreases as well. Furthermore, patients with Lennox-Gastaut Syndrome may have improved outcomes after corpus callosotomy. Overall, our findings suggest that complete callosotomy is an effective surgical intervention for poorly localized, treatment-refractory epilepsy in adults.Funding: No funding