Journal of Neurosurgery
James M. Johnston Jr., Francesco T. Mangano, Jeffrey G. Ojemann, Tae Sung Park, Edwin Trevathan and Matthew D. Smyth
The purpose of this study was to better define the incidence of complications associated with placement of subdural electrodes for localization of seizure foci and functional mapping in children.
The authors retrospectively reviewed the records of 112 consecutive patients (53 boys, 59 girls; mean age 10.9 years, range 10 months–21.7 years) with medically intractable epilepsy who underwent invasive monitoring at the Pediatric Epilepsy Center at St. Louis Children’s Hospital between January 1994 and July 2005. There were 122 implantation procedures (85 grids and strips, 32 strips only, five grids only, four with additional depth electrodes), with a mean monitoring period of 7.1 days (range 2–21 days). Operative complications included the need for repeated surgery for additional electrode placement (5.7%); wound infection (2.4%); cerebrospinal fluid leak (1.6%); and subdural hematoma, symptomatic pneumocephalus, bone flap osteomyelitis, and strip electrode fracture requiring operative retrieval (one patient [0.8%] each). There were four cases of transient neurological deficit (3.3%) and no permanent deficit or death associated with invasive monitoring.
Placement of subdural grid and strip electrodes for invasive video electroencephalographic monitoring is generally well tolerated in the pediatric population. The authors found that aggressive initial electrode coverage was not associated with higher rates of blood transfusion or perioperative complications, and reduced the frequency of repeated operations for placement of supplemental electrodes.
Matthew D. Smyth, David D. Limbrick Jr., Jeffrey G. Ojemann, John Zempel, Shenandoah Robinson, Donncha F. O'Brien, Russell P. Saneto, Monisha Goyal, Richard E. Appleton, Francesco T. Mangano and Tae Sung Park
The authors conducted a multiinstitutional, retrospective analysis to better define outcome and prognostic indicators for temporal lobe epilepsy surgery for suspected mesial temporal sclerosis (MTS) in young children.
Data were collected for all children undergoing temporal resections at four epilepsy centers over approximately 10 years. Children with a histopathological diagnosis of neoplasm were excluded.
Forty-nine patients (28 boys and 21 girls) were included in the study. Their mean age at surgery was 9.1 years (range 1.25–13.9 years). The mean age at seizure onset was 3.2 years (range birth–10 years). Histopathological examination demonstrated MTS in 26 cases, gliosis in nine, dysplasia in five, gliosis with dysplasia in four, and nonspecific or normal findings in five. Forty-one anterior temporal lobectomies (nine tailored) and eight selective amygdalohippocampectomies were performed (28 left side, 21 right side). Twenty-nine children (59.2%) underwent invasive monitoring. Operative complications included extraaxial hematomas (two cases), cerebrospinal fluid leaks (two cases), and hydrocephalus (one case), each in children undergoing invasive monitoring. The mean duration of follow up was 26.4 months (range 5–74 months) overall and 23.9 months (range 6–74 months) for the Engel Class I subgroup. Outcomes at the most recent follow-up examination were categorized as Engel Class I–II in 31 (63.3%) of 49 children overall, 20 (76.9%) of 26 children with confirmed MTS, four (36.4%) of 11 children with gliosis, and four (57.1%) of seven children with dysplasia. All patients who underwent selective amygdalohippocampectomies had confirmed MTS and Engel Class I outcomes. Patients with more than one seizure type (p = 0.048) or moderate to severe developmental delay (p = 0.03) had significantly worse outcomes (Engel Class III or IV). Age at seizure onset, age at surgery, and duration of seizure disorder were not significantly related to outcome. There was a trend for bilateral or extratemporal findings on electroencephalography (EEG) (p = 0.157), high preoperative seizure frequency (p = 0.097), and magnetic resonance (MR) imaging findings inconsistent with MTS (p = 0.142) to be associated with worse outcome, although it did not reach statistical significance. In only 12 (46.1%) of the 26 patients with confirmed MTS was the condition prospectively diagnosed on preoperative MR imaging.
Younger children with temporal lobe epilepsy have satisfying surgical outcomes, particularly when MTS is present. Magnetic resonance imaging may not be as sensitive in detecting MTS in children as in older patients. Negative predictors identified include multiple seizure types and preoperative developmental delay. Multifocal or bilateral EEG findings, high preoperative seizure frequency, and MR imaging findings inconsistent with MTS also independently suggested worse outcome.