WASHINGTON, DC—Hemispherectomy can be curative or result in significant improvement in seizure frequency among adult patients with refractory epilepsy, according to research presented at the 67th Annual Meeting of the American Epilepsy Society.
Among 65 adult patients who underwent functional hemispherectomy and 25 adults who underwent anatomic hemispherectomy, 80% of patients achieved complete seizure freedom, reported Courtney M. Schusse, MD, and colleagues. Overall morbidity was low, and patients who underwent formal IQ testing showed overall stability or improvement.
“The procedure is generally well tolerated without significant morbidity,” stated Dr. Schusse, a Fellow in Clinical Neurophysiology and Epilepsy at Barrow Neurological Institute in Phoenix, and colleagues.
The researchers conducted a literature review of hemispherectomy studies, as well as a chart review of six patients who had had the procedure at the Barrow Neurological Institute. Only case series that included patients 18 and older were included. The investigators analyzed the findings of preoperative tests, which included EEG and MRI results for all patients, and they reviewed neuropsychologic assessments and PET and fMRI results when available.
All patients had varying degrees of hemiparesis and visual field abnormalities, and a majority of patients were ambulatory at baseline. All patients had experienced multiple daily seizures. The primary outcome measure was seizure freedom, and secondary outcome measures were functional and cognitive outcomes.
For the 90 patients who underwent hemispherectomy, the length of follow-up was from two to 456 months. Fifty procedures were left hemispheric, and the remaining 40 were right hemispheric surgeries. Of the six cases that were observed at the authors’ institution, seizures resulted from perinatal stroke in four patients, from early childhood hemorrhage in one patient, and from viral encephalitis in one patient.
A total of 72 patients reported complete seizure freedom after the surgery and achieved an Engel Classification of IA. More than 90% of patients had an Engel Class I or II outcome. The researchers observed no significant differences between patients who had functional versus anatomic hemispherectomies or between those who had left versus right surgeries.
Nineteen patients had some worsening of hemiparesis, and nine patients had postoperative speech or language dysfunction. No patients lost ambulatory or significant functional ability, and two patients who were not ambulatory preoperatively were able to walk independently after surgery. Forty-one patients underwent additional formal IQ testing postsurgery, and the investigators observed overall stability or improvement in these patients.
Reasons for the relative scarcity of hemispherectomies in adults are not clear, but concerns over the lack of neuroplasticity in adults and the suspected potential for significant functional decline may be the most likely explanations. “New functional impairment, regardless of seizure freedom, may have a profound economic and social impact on an adult due to [potential changes in] employment or driving status,” said Dr. Schusse.
Significant functional impairment has been rare, and functional improvement occurs in many patients, she added. “Language deficits are a concern with late surgeries, and language dysfunction was found in 18% of patients undergoing left-sided surgeries,” Dr. Schusse commented. “Overall, however, the majority of patients who underwent preoperative and postoperative assessments showed stability or improvement in IQ.”