Contemporaneous evaluation of patient experience, surgical strategy, and seizure outcomes in patients undergoing stereoelectroencephalography or subdural electrode monitoring

Abstract

ObjectiveIntracranial electrographic localization of the seizure onset zone (SOZ) can guide surgical approaches for medically refractory epilepsy patients, especially when the presurgical workup is discordant or functional cortical mapping is required. Minimally invasive stereotactic placement of depth electrodes, stereoelectroencephalography (SEEG), has garnered increasing use, but limited data exist to evaluate its postoperative outcomes in the context of the contemporaneous availability of both SEEG and subdural electrode (SDE) monitoring. We aimed to assess the patient experience, surgical intervention, and seizure outcomes associated with these two epileptic focus mapping techniques during a period of rapid adoption of neuromodulatory and ablative epilepsy treatments.MethodsWe retrospectively reviewed 66 consecutive adult intracranial electrode monitoring cases at our institution between 2014 and 2017. Monitoring was performed with either SEEG (n = 47) or SDEs (n = 19).ResultsBoth groups had high rates of SOZ identification (SEEG 91.5%, SDE 88.2%, P = .69). The majority of patients achieved Engel class I (SEEG 29.3%, SDE 35.3%) or II outcomes (SEEG 31.7%, SDE 29.4%) after epilepsy surgery, with no significant difference between groups (P = .79). SEEG patients reported lower median pain scores (P = .03) and required less narcotic pain medication (median = 94.5 vs 594.6 milligram morphine equivalents, P = .0003). Both groups had low rates of symptomatic hemorrhage (SEEG 0%, SDE 5.3%, P = .11). On multivariate logistic regression, undergoing resection or ablation (vs responsive neurostimulation/vagus nerve stimulation) was the only significant independent predictor of a favorable outcome (adjusted odds ratio = 25.4, 95% confidence interval = 3.48‐185.7, P = .001).SignificanceAlthough both SEEG and SDE monitoring result in favorable seizure control, SEEG has the advantage of superior pain control, decreased narcotic usage, and lack of routine need for intensive care unit stay. Despite a heterogenous collection of epileptic semiologies, seizure outcome was associated with the therapeutic surgical modality and not the intracranial monitoring technique. The potential for an improved postoperative experience makes SEEG a promising method for intracranial electrode monitoring.

Comparative Effectiveness of Stereotactic Electroencephalography Versus Subdural Grids in Epilepsy Surgery

“…In this context, the surgical risks of invasive EEG, regardless of the modality (SDE or SEEG), are often justifiable to improve patient survival and quality of life 7,34 . However, current data comparing the 2 modalities are limited to expert‐opinion review articles, 3,35–37 single‐center descriptive studies with insufficient sample size to compare outcomes, 7,38 an exclusive focus on surgical complications and length of stay favoring SEEG, 4 with the 2 single‐center case series on the topic reporting unadjusted estimates of seizure freedom (1 with equivalent outcomes between SEEG and SDE, 5 and 1 with better outcomes of SEEG compared with SDE 2 ). All studies reported important differences in the baseline characteristics of patients who had SDE versus SEEG, limiting any meaningful conclusions on how the 2 modalities truly compare.…”

“…As with other significantly different neurosurgical procedures, randomized ccontrolled trials (RCTs) comparing the 2 methods are virtually impossible 6 : only a handful of surgical programs have the versatility needed to offer both procedures, 3 and patients often have strong preferences given the significantly different approaches. 7 Over the past 20 years, the number of iEEG investigations without a subsequent therapeutic resection has tripled in the USA and Europe. 8 Clinical practice has become preference sensitive, rather than evidence based.…”

Probabilistic comparison of gray and white matter coverage between depth and surface intracranial electrodes in epilepsy

“…If the seizure onset zone was thought to arise from a deep lesion or if there were a reason to record bilaterally, the use of depth electrodes might be favored 3 , 6 . Risk profiles differ between both approaches, and this also plays a role in choosing which modality to use 7 – 12 . Finally, each method of intracranial monitoring may have advantages over others, yet the decision to use a certain modality over another at many US institutions may have more to do with preferred clinical practice at a given center 3 .…”

Intracranial monitoring contributes to seizure freedom for temporal lobectomy patients with nonconcordant preoperative data

“…These findings suggest that previous results regarding the superiority of sEEG over SDE/DE may be driven by the data from extratemporal cases. 22,27,37,38 To the best of our knowledge, our study is the first to investigate the efficiency of intracranial monitoring approaches in a focused and uniform manner, in terms of patient population (TLE) and surgical treatment (ATL).…”