Neurologists must consider various factors when deciding whether open resection or SLAH is the better option for a given patient. “Our prior work has shown that SLAH will not cause naming or object recognition deficits, while such deficits will result in a substantial proportion of patients undergoing open resection procedures,” said Dr. Drane. “Declarative memory can seemingly be hurt by either procedure, although it would appear that rates of decline are substantially less following SLAH. As functional status appears to be related to cognitive outcome, SLAH would always be the better choice from the standpoint of risk analysis, particularly since one can almost always go back an complete an open resection at a later date.
“Seizure freedom rates appear to be slightly higher with open resection than with SLAH,” Dr. Drane continued. “This [result] would be the one factor that would represent the one reason to opt for an open resection rather than SLAH. Factors that might push one in this direction could be risk for SUDEP (i.e., someone at very high risk may want to just be done with the seizures) and impaired baseline cognitive functioning (i.e., someone with severely impaired cognitive functioning might be viewed as having less to lose). In the latter case, however, we would caution that low-functioning individuals can sometimes lose their remaining functional abilities even if we cannot do a very good job of measuring cognitive change in such cases due to their poor baseline performance.”
The hemisphere to undergo operation also may influence the choice of procedure. “Some epileptologists will suggest that the choice of using SLAH is more important for patients having surgery involving their language-dominant cerebral hemisphere,” said Dr. Drane. “While postsurgical deficits in these patients are clearly more easy to identify, I would argue that a case can be made for starting with SLAH in the nondominant temporal lobe cases as well. Many of the functions that can be potentially harmed by surgical procedures involving the nondominant (typically right) hemisphere have more subtle effects, but their cumulative impact can yet be harmful.”
The study was partially supported by funding from the National Institutes of Health and Medtronic. The investigators did not report any conflicts of interest.
SOURCE: Drane DL et al. AES 2019. Abstract 1.34.
