Introduction: Deep brain stimulation under general anesthesia (“asleep deep brain stimulation”) has not been previously reported for essential tremor. This is in part due to the inability to visualize the target (ventral intermediate nucleus) on magnetic resonance imaging (MRI). We evaluate the efficacy of this asleep technique in treating essential tremor by indirect ventral intermediate nucleus targeting.
Methods: Consecutive cases of initial deep brain stimualtion for essential tremor by a single surgeon, performed with patients awake (n=40, intraoperative test stimulation without microelectrode recording) or asleep (n=17, under general anesthesia) were retrospectively reviewed. Targeting proceeded with standardized anatomic coordinates on preoperative MRI. Intraoperative computerized tomography was used for stereotactic registration and lead-position confirmation. Functional outcomes were evaluated with pre- and postoperative Bain and Findley Tremor Activities of Daily Living scores. Statistics are presented as means ± standard deviations. Outcomes were compared with independent samples t-tests. P<0.05 was considered statistically significant.
Results: 29 leads were placed asleep; 60 were placed awake. Bain and Findley Tremor scores were not significantly different preoperatively for awake versus asleep cohorts (P=0.2). Percentage of postoperative improvement was not significantly different between asleep (48.6%) and awake (45.5%) cohorts (P=0.35). Euclidean error (mm) was higher for awake versus. asleep (1.7±0.8 vs. 1.2±0.4, P=0.01) and radial error (mm) trended higher for awake versus asleep patients (1.3±0.8 vs. 0.9±0.5, P=0.06). There were no perioperative complications.
Conclusions: In our initial experience, asleep ventral intermediate nucleus deep brain stimulation for essential tremor without intraoperative test stimulation can be performed safely and effectively.
Patient Care: This is the first report of performing "asleep" DBS (DBS under general anesthesia) for the treatment of Essential Tremor. This method is revolutionary and will create access to DBS for Essential Tremor patients who would otherwise be excluded from an "awake" surgery due to medical co-morbidities. In addition, this will significantly improve the patient's surgical experience, decrease operative time, and improve operating room work flow. A randomized, controlled trial is currently underway at our institution.
Learning Objectives: At the conclusion of this presentation, participants should be able to 1) Understand the method of "asleep" DBS, or DBS under general anesthesia 2) Discuss the benefits and shortcomings of placing DBS under the "awake" vs. "asleep technique 3) Discuss the utility of "asleep" DBS for both Parkinson's and Essential Tremor in the future