A historical perspective: Stereotactic lesions for the treatment of epilepsy

AbstractPurposeMost deep brain stimulation targets for movement disorders were derived from effective ablative surgery targets. Similarly effective lesion targets for epilepsy control may help refine brain stimulation targeting for epilepsy. A literature review of past stereotactic lesions for epilepsy treatment was performed to provide historical context and possible anatomical guidance for current and future attempts at controlling epilepsy with electrical stimulation. This work was undertaken to provide insights for electrical stimulation targets in epilepsy treatment based on outcomes from previous ablative therapies.MethodsA MEDLINE search was conducted for studies with the words “stereotactic surgery” and “epilepsy.” Post-operative results for 619 patients with stereotactic brain lesions targeting various anatomical foci were standardized using a modified Engel scale (1 ‘free of seizures’ to 3 ‘no significant improvement’). Each individual patient was entered into a database as a unique data point.ResultsThere was a statistically significant difference in reported seizure control among the different procedures and seizure types. The procedures that produced the best seizure control outcomes were the hippocampectomy, pallido-amygdalotomy, and amygdalohippocampectomy. Simple partial motor and combined generalized tonic clonic with complex partial seizure types demonstrated the best outcomes following surgery; complex partial and generalized tonic had the worst outcomes.ConclusionsThe results of this study demonstrate the location of brain lesions has a significant effect on seizure control. Thus, future research designed to optimize brain stimulation targets for epilepsy control may be informed by previous ablative outcomes

Anterior cervical fusion versus minimally invasive posterior keyhole decompression for cervical radiculopathy

Background: Treatment modalities for degenerative cervical spine disease are widely debated and refined as new surgical techniques are developed. The current case series compares two common cervical spine procedures, anterior cervical discectomy and fusion (ACDF) and minimally invasive posterior keyhole foraminotomy (MIPKF). The decision making process of the two surgical approaches is discussed, and the long term outcomes are presented. Methods: A retrospective chart review of surgical patients having either an ACDF or MIPKF with an extensive chart review. Over 570 patient charts were identified and reviewed between 1994 and 2011. After exclusion, a total of 268 patients were identified in the ACDF group, and 112 patients were identified in the MIPKF group. Primary outcome measurement was the need for any reoperation, whether at the same level or adjacent levels due to recurrence of disease or adjacent level disease. Results: An average follow-up of 11.8 (±3.0) years in the ACDF group and 6.4 (±4.4) years in the MIPKF group was determined over a 17 year period. There was a reoperation rate of 2.6% in the ACDF group and 2.7% in the MIPKF group during the 17 year time period. Conclusion: ACDF has been demonstrated to be an effective surgical procedure in treating degenerative spine disease in patients with radiculopathy and/or myelopathy. However, in a population with isolated radiculopathy and radiological imaging confirming an anterolateral disc or osteophyte complex, the MIPKF can provide similar results without the associated risks that accompany an anterior cervical spine fusion

Two‐year seizure reduction in adults with medically intractable partial onset epilepsy treated with responsive neurostimulation: Final results of the RNS System Pivotal trial

OBJECTIVE: To demonstrate the safety and effectiveness of responsive stimulation at the seizure focus as an adjunctive therapy to reduce the frequency of seizures in adults with medically intractable partial onset seizures arising from one or two seizure foci. METHODS: Randomized multicenter double-blinded controlled trial of responsive focal cortical stimulation (RNS System). Subjects with medically intractable partial onset seizures from one or two foci were implanted, and 1 month postimplant were randomized 1:1 to active or sham stimulation. After the fifth postimplant month, all subjects received responsive stimulation in an open label period (OLP) to complete 2 years of postimplant follow-up. RESULTS: All 191 subjects were randomized. The percent change in seizures at the end of the blinded period was −37.9% in the active and −17.3% in the sham stimulation group (p = 0.012, Generalized Estimating Equations). The median percent reduction in seizures in the OLP was 44% at 1 year and 53% at 2 years, which represents a progressive and significant improvement with time (p < 0.0001). The serious adverse event rate was not different between subjects receiving active and sham stimulation. Adverse events were consistent with the known risks of an implanted medical device, seizures, and of other epilepsy treatments. There were no adverse effects on neuropsychological function or mood. SIGNIFICANCE: Responsive stimulation to the seizure focus reduced the frequency of partial-onset seizures acutely, showed improving seizure reduction over time, was well tolerated, and was acceptably safe. The RNS System provides an additional treatment option for patients with medically intractable partial-onset seizures

Brain-responsive neurostimulation in patients with medically intractable mesial temporal lobe epilepsy.

OBJECTIVE: Evaluate the seizure-reduction response and safety of mesial temporal lobe (MTL) brain-responsive stimulation in adults with medically intractable partial-onset seizures of mesial temporal lobe origin. METHODS: Subjects with mesial temporal lobe epilepsy (MTLE) were identified from prospective clinical trials of a brain-responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2-6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. RESULTS: There were 111 subjects with MTLE; 72% of subjects had bilateral MTL onsets and 28% had unilateral onsets. Subjects had one to four leads placed; only two leads could be connected to the device. Seventy-six subjects had depth leads only, 29 had both depth and strip leads, and 6 had only strip leads. The mean follow-up was 6.1 ± (standard deviation) 2.2 years. The median percent seizure reduction was 70% (last observation carried forward). Twenty-nine percent of subjects experienced at least one seizure-free period of 6 months or longer, and 15% experienced at least one seizure-free period of 1 year or longer. There was no difference in seizure reduction in subjects with and without mesial temporal sclerosis (MTS), bilateral MTL onsets, prior resection, prior intracranial monitoring, and prior vagus nerve stimulation. In addition, seizure reduction was not dependent on the location of depth leads relative to the hippocampus. The most frequent serious device-related adverse event was soft tissue implant-site infection (overall rate, including events categorized as device-related, uncertain, or not device-related: 0.03 per implant year, which is not greater than with other neurostimulation devices). SIGNIFICANCE: Brain-responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior MTL resection