An Investigation Into the Characteristics of Peri-Lead Edema After Deep Brain Stimulation Surgery

INTRODUCTION: Peri-lead edema (PLE) is an increasingly recognized effect of deep brain stimulation (DBS) surgery. Despite this, PLE remains poorly characterized, with reports of the phenomenon’s incidence and clinical meaning differing widely among studies. METHODS: We regularly obtained 2 CT scans at each stage of routine DBS surgery (lead implantation and implantable pulse generator implantation) in 55 consecutive patients. Both image sets (early and late postoperative CTs) were inspected for PLE, and edema volume was manually segmented. Clinical characteristics were procured by chart review. Edema volume was assessed quantitatively and compared with clinical postoperative course to investigate any possible correlations. RESULTS: Zero (0%) and 24 (43.6%) patients were found to have PLE at stage one and stage two imaging, respectively. Nineteen of the edema patients were treated for Parkinson’s Disease and 5 for essential tremor. DBS targets were STN (12), VIM (6), and GPi (6). Mean edema volume was 8.10 ± 5.66 mL, with a median of 8.91 mL and ranging from 1.60 to 26.90 mL. Closer inspection of volume into left- and right-hemispheric PLE ascertained no discernible difference between each or to the total (ANOVA F < 0.0005, p = 0.99), nor did an analogous partition into volume by target (ANOVA F = 0.19, p = 0.90). Three patients experienced symptomatic PLE, all of whom had DBS targeting VIM. One patient had experienced seizure, another with altered mental status and gait instability, and the last had dizziness and weakness. All fully recovered following antiepileptic medication for the patient with seizure, and the other two following steroid administration. CONCLUSIONS: PLE occurs in about half of the patients undergoing DBS and is usually asymptomatic. Symptomatic PLE may be managed to resolution in an outpatient setting with steroid administration.