Seizure Surgery

Epilepsy is a disorder of the nervous system that affects over 2 million people worldwide, with the highest incidence in children. Surgical management of a child with refractory epilepsy may result in improved seizure control and better quality of life. The perioperative management of the pediatric patient for seizure surgery presents a considerable challenge to the anesthesiologist. Primary concerns include the interactions of antiepileptic medications with anesthetic drugs, the effects of anesthetic agents and medications on intraoperative neuromonitoring, and management of seizures while under anesthesia. This chapter will focus on anesthetic concerns and management for pediatric patients presenting for seizure surgery.

First In-Human Experience With Complete Integration of Neuromodulation Device Within a Customized Cranial Implant

BACKGROUND Neuromodulation devices have the potential to transform modern day treatments for patients with medicine-resistant neurological disease. For instance, the NeuroPace System (NeuroPace Inc, Mountain View, California) is a Food and Drug Administration (FDA)-approved device developed for closed-loop direct brain neurostimulation in the setting of drug-resistant focal epilepsy. However, current methods require placement either above or below the skull in nonanatomic locations. This type of positioning has several drawbacks including visible deformities and scalp pressure from underneath leading to eventual wound healing difficulties, micromotion of hardware with infection, and extrusion leading to premature explantation. OBJECTIVE To introduce complete integration of a neuromodulation device within a customized cranial implant for biocompatibility optimization and prevention of visible deformity. METHODS We report a patient with drug-resistant focal epilepsy despite previous seizure surgery and maximized medical therapy. Preoperative imaging demonstrated severe resorption of previous bone flap causing deformity and risk for injury. She underwent successful responsive neurostimulation device implantation via complete integration within a clear customized cranial implant. RESULTS The patient has recovered well without complication and has been followed closely for 180 d. Device interrogation with electrocorticographic data transmission has been successfully performed through the clear implant material for the first time with no evidence of any wireless transmission interference. CONCLUSION Cranial contour irregularities, implant site infection, and bone flap resorption/osteomyelitis are adverse events associated with implantable neurotechnology. This method represents a novel strategy to incorporate all future neuromodulation devices within the confines of a low-profile, computer-designed cranial implant and the newfound potential to eliminate contour irregularities, improve outcomes, and optimize patient satisfaction.

Is Seizure Surgery an Option for Patients with Very Low IQ?

Seizure Outcome after Resective Epilepsy Surgery in Patients with Low IQ. Malmgren K, Olsson I, Engman E, Flink R, Rydenhag B. Brain 2008;131(Pt 2):535–542. Epilepsy surgery has been questioned for patients with low IQ, since a low cognitive level is taken to indicate a widespread disturbance of cerebral function with unsatisfactory prognosis following resective surgery. The prevalence of epilepsy in patients with cognitive dysfunction is, however, higher than in the general population and the epilepsy is often more severe and difficult to treat. It is therefore important to try to clarify whether IQ predicts seizure outcome after resective epilepsy surgery. The Swedish National Epilepsy Surgery Register, which includes data on all epilepsy surgery procedures in Sweden since 1990, was analysed for all resective procedures performed 1990–99. Sustained seizure freedom with or without aura at the 2-year follow-up was analysed as a function of pre-operative IQ level categorized as IQ <50, IQ 50–69 and IQ ≥70 and was also adjusted for the following variables: age at epilepsy onset, age at surgery, pre-operative seizure frequency, pre-operative neurological impairment, resection type and histopathological diagnosis. Four hundred and forty-eight patients underwent resective epilepsy surgery in Sweden from 1990 to 1999 and completed the 2-year follow-up: 72 (16%) had IQ <70, (18 with IQ <50 and 54 with IQ 50–69) and 376 IQ ≥70. There were 313 adults and 135 children ≤18 years. Three hundred and twenty-five patients underwent temporal lobe resections (TLR) and 123 underwent various extratemporal resections (XTLR). At the 2-year follow-up, 56% (252/448) of the patients were seizure free: 22% (4/18) in the IQ <50 group, 37% (20/54) in the IQ 50–69 group and 61% (228β76) in the IQ ≥70 group. There was a significant relation between IQ category and seizure freedom [odds ratio (OR) 0.41, 95% confidence interval (CI) 0.27–0.62] and this held also when adjusting for clinical variables [OR 0.58 (95% CI 0.35–0.95)]. In this population-based epilepsy surgery series, IQ level was shown to be an independent predictor of seizure freedom at the 2-year follow-up. However, many of the low-IQ patients benefit from surgery, especially patients with lesions. Low IQ should not exclude patients from resective epilepsy surgery, but is an important prognostic factor to consider in the counselling process.