While temporal lobe epilepsy (TLE) is the most common epilepsy syndrome in adults, seizures in children are more often extratemporal in origin. Extra–temporal lobe epilepsy (ETLE) in pediatric patients is often medically refractory, leading to significantly diminished quality of life. Seizure outcomes after resective surgery for pediatric ETLE vary tremendously in the literature, given diverse patient and epilepsy characteristics and small sample sizes. The authors performed a systematic review and meta-analysis of studies including 10 or more pediatric patients (age ≤ 19 years) published over the last 20 years examining seizure outcomes after resective surgery for ETLE, excluding hemispherectomy. Thirty-six studies were examined. These 36 studies included 1259 pediatric patients who underwent resective surgery for ETLE. Seizure freedom (Engel Class I outcome) was achieved in 704 (56%) of these 1259 patients postoperatively, and 555 patients (44%) continued to have seizures (Engel Class II–IV outcome). Shorter epilepsy duration (≤ 7 years, the median value in this study) was more predictive of seizure freedom than longer (> 7 years) seizure history (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.07–2.14), suggesting that earlier intervention may be beneficial. Also, lesional epilepsy was associated with better seizure outcomes than nonlesional epilepsy (OR 1.34, 95% CI 1.19–1.49). Other predictors of seizure freedom included an absence of generalized seizures (OR 1.61, 95% CI 1.18–2.35) and localizing ictal electroencephalographic findings (OR 1.55, 95% CI 1.24–1.93). In conclusion, seizure outcomes after resective surgery for pediatric ETLE are less favorable than those associated with temporal lobectomy, but seizure freedom may be more common with earlier intervention and lesional epilepsy etiology. Children with continued debilitating seizures despite failure of multiple medication trials should be referred to a comprehensive pediatric epilepsy center for further medical and surgical evaluation.
Dario J. Englot, Jonathan D. Breshears, Peter P. Sun, Edward F. Chang and Kurtis I. Auguste
Jonathan D. Breshears, Michael E. Ivan, Jennifer A. Cotter, Andrew W. Bollen, Phillip V. Theodosopoulos and Mitchel S. Berger
Gliomas of the cranial nerve root entry zone are rare clinical entities. There have been 11 reported cases in the literature, including only 2 glioblastomas. The authors report the case of a 67-year-old man who presented with isolated facial numbness and was found to have a glioblastoma involving the trigeminal nerve root entry zone. After biopsy the patient completed treatment with conformal radiation and concomitant temozolomide, and at 23 weeks after surgery he demonstrated symptom progression despite the treatment described. This is the first reported case of a glioblastoma of the trigeminal nerve root entry zone.
Jonathan D. Breshears, Annette M. Molinaro and Edward F. Chang
The human ventral sensorimotor cortex (vSMC) is involved in facial expression, mastication, and swallowing, as well as the dynamic and highly coordinated movements of human speech production. However, vSMC organization remains poorly understood, and previously published population-driven maps of its somatotopy do not accurately reflect the variability across individuals in a quantitative, probabilistic fashion. The goal of this study was to describe the responses to electrical stimulation of the vSMC, generate probabilistic maps of function in the vSMC, and quantify the variability across individuals.
Photographic, video, and stereotactic MRI data of intraoperative electrical stimulation of the vSMC were collected for 33 patients undergoing awake craniotomy. Stimulation sites were converted to a 2D coordinate system based on anatomical landmarks. Motor, sensory, and speech stimulation responses were reviewed and classified. Probabilistic maps of stimulation responses were generated, and spatial variance was quantified.
In 33 patients, the authors identified 194 motor, 212 sensory, 61 speech-arrest, and 27 mixed responses. Responses were complex, stereotyped, and mostly nonphysiological movements, involving hand, orofacial, and laryngeal musculature. Within individuals, the presence of oral movement representations varied; however, the dorsal-ventral order was always preserved. The most robust motor responses were jaw (probability 0.85), tongue (0.64), lips (0.58), and throat (0.52). Vocalizations were seen in 6 patients (0.18), more dorsally near lip and dorsal throat areas. Sensory responses were spatially dispersed; however, patients' subjective reports were highly precise in localization within the mouth. The most robust responses included tongue (0.82) and lips (0.42). The probability of speech arrest was 0.85, highest 15–20 mm anterior to the central sulcus and just dorsal to the sylvian fissure, in the anterior precentral gyrus or pars opercularis.
The authors report probabilistic maps of function in the human vSMC based on intraoperative cortical electrical stimulation. These results define the expected range of mapping outcomes in the vSMC of a single individual and shed light on the functional organization of the vSMC supporting speech motor control and nonspeech functions.
Joseph A. Osorio, Jonathan D. Breshears, Omar Arnaout, Neil G. Simon, Ashley M. Hastings-Robinson, Pedram Aleshi and Michel Kliot
The objective of this study was to provide a technique that could be used in the preoperative period to facilitate the surgical exploration of peripheral nerve pathology.
The authors describe a technique in which 1) ultrasonography is used in the immediate preoperative period to identify target peripheral nerves, 2) an ultrasound-guided needle electrode is used to stimulate peripheral nerves to confirm their position, and then 3) a methylene blue (MB) injection is performed to mark the peripheral nerve pathology to facilitate surgical exploration.
A cohort of 13 patients with varying indications for peripheral nerve surgery is presented in which ultrasound guidance, stimulation, and MB were used to localize and create a road map for surgeries.
Preoperative ultrasound-guided MB administration is a promising technique that peripheral nerve surgeons could use to plan and execute surgery.
Adib A. Abla, Cameron M. McDougall, Jonathan D. Breshears and Michael T. Lawton
Intracranial-to-intracranial (IC-IC) bypasses are alternatives to traditional extracranial-to-intracranial (EC-IC) bypasses to reanastomose parent arteries, reimplant efferent branches, revascularize branches with in situ donor arteries, and reconstruct bifurcations with interposition grafts that are entirely intracranial. These bypasses represent an evolution in bypass surgery from using scalp arteries and remote donor sites toward a more local and reconstructive approach. IC-IC bypass can be utilized preferentially when revascularization is needed in the management of complex aneurysms. Experiences using IC-IC bypass, as applied to posterior inferior cerebellar artery (PICA) aneurysms in 35 patients, were reviewed.
Patients with PICA aneurysms and vertebral artery (VA) aneurysms involving the PICA’s origin were identified from a prospectively maintained database of the Vascular Neurosurgery Service, and patients who underwent bypass procedures for PICA revascularization were included.
During a 17-year period in which 129 PICA aneurysms in 125 patients were treated microsurgically, 35 IC-IC bypasses were performed as part of PICA aneurysm management, including in situ p3-p3 PICA-PICA bypass in 11 patients (31%), PICA reimplantation in 9 patients (26%), reanastomosis in 14 patients (40%), and 1 V3 VA-to-PICA bypass with an interposition graft (3%). All aneurysms were completely or nearly completely obliterated, 94% of bypasses were patent, 77% of patients were improved or unchanged after treatment, and good outcomes (modified Rankin Scale ≤ 2) were observed in 76% of patients. Two patients died expectantly. Ischemic complications were limited to 2 patients in whom the bypasses occluded, and permanent lower cranial nerve morbidity was limited to 3 patients and did not compromise independent function in any of the patients.
PICA aneurysms receive the application of IC-IC bypass better than any other aneurysm, with nearly one-quarter of all PICA aneurysms treated microsurgically at our center requiring bypass without a single EC-IC bypass. The selection of PICA bypass is almost algorithmic: trapped aneurysms at the PICA origin or p1 segment are revascularized with a PICA-PICA bypass, with PICA reimplantation as an alternative; trapped p2 segment aneurysms are reanastomosed, bypassed in situ, or reimplanted; distal p3 segment aneurysms are reanastomosed or revascularized with a PICA-PICA bypass; and aneurysms of the p4 segment that are too distal for PICA-PICA bypass are reanastomosed. Interposition grafts are reserved for when these 3 primary options are unsuitable. A constructive approach that preserves the PICA with direct clipping or replaces flow with a bypass when sacrificed should remain an alternative to deconstructive PICA occlusion and endovascular coiling when complete aneurysm occlusion is unlikely.
Edward F. Chang, Jonathan D. Breshears, Kunal P. Raygor, Darryl Lau, Annette M. Molinaro and Mitchel S. Berger
Functional mapping using direct cortical stimulation is the gold standard for the prevention of postoperative morbidity during resective surgery in dominant-hemisphere perisylvian regions. Its role is necessitated by the significant interindividual variability that has been observed for essential language sites. The aim in this study was to determine the statistical probability distribution of eliciting aphasic errors for any given stereotactically based cortical position in a patient cohort and to quantify the variability at each cortical site.
Patients undergoing awake craniotomy for dominant-hemisphere primary brain tumor resection between 1999 and 2014 at the authors' institution were included in this study, which included counting and picture-naming tasks during dense speech mapping via cortical stimulation. Positive and negative stimulation sites were collected using an intraoperative frameless stereotactic neuronavigation system and were converted to Montreal Neurological Institute coordinates. Data were iteratively resampled to create mean and standard deviation probability maps for speech arrest and anomia. Patients were divided into groups with a “classic” or an “atypical” location of speech function, based on the resultant probability maps. Patient and clinical factors were then assessed for their association with an atypical location of speech sites by univariate and multivariate analysis.
Across 102 patients undergoing speech mapping, the overall probabilities of speech arrest and anomia were 0.51 and 0.33, respectively. Speech arrest was most likely to occur with stimulation of the posterior inferior frontal gyrus (maximum probability from individual bin = 0.025), and variance was highest in the dorsal premotor cortex and the posterior superior temporal gyrus. In contrast, stimulation within the posterior perisylvian cortex resulted in the maximum mean probability of anomia (maximum probability = 0.012), with large variance in the regions surrounding the posterior superior temporal gyrus, including the posterior middle temporal, angular, and supramarginal gyri. Patients with atypical speech localization were far more likely to have tumors in canonical Broca's or Wernicke's areas (OR 7.21, 95% CI 1.67–31.09, p < 0.01) or to have multilobar tumors (OR 12.58, 95% CI 2.22–71.42, p < 0.01), than were patients with classic speech localization.
This study provides statistical probability distribution maps for aphasic errors during cortical stimulation mapping in a patient cohort. Thus, the authors provide an expected probability of inducing speech arrest and anomia from specific 10-mm2 cortical bins in an individual patient. In addition, they highlight key regions of interindividual mapping variability that should be considered preoperatively. They believe these results will aid surgeons in their preoperative planning of eloquent cortex resection.