Somatosensory evoked potential: Preventing brachial plexus injury in transaxillary robotic surgery

Abstract

Objectives/hypothesis: The potential for brachial plexopathy due to arm positioning is a major concern regarding the robotic transaxillary approach. Intraoperative nerve monitoring via somatosensory evoked potential (SSEP) has been suggested to prevent such injury. In this study, we examined the use of SSEP in detecting imminent brachial plexus traction during robotic transaxillary thyroid and parathyroid surgery.

Study design: Retrospective case series.

Methods: A analysis was performed for all patients undergoing robotic transaxillary surgery with continuous intraoperative SSEP monitoring at a North American institution between 2015 and 2017. A significant intraoperative SSEP change was defined as a decrease in signal amplitude of >50% or an increase in latency of >10% from baseline established during preoperative positioning.

Results: One hundred thirty-seven robotic transaxillary surgeries using SSEP monitoring were performed on 123 patients. Seven patients (5.1%) developed significant changes, with an average SSEP amplitude reduction of 73% ± 12% recorded at the signals' nadir. Immediate arm repositioning resulted in recovery of signals and complete return to baseline parameters in 14.3 ± 9.2 minutes. There was no difference in age (40.4 ± 9.4 years vs. 44.5 ± 13.4 years; P = .31) or body mass index (27.3 ± 3.7 kg/m² vs. 26.9 ± 6.1 kg/m² ; P = .79) between cases with and without SSEP change. Operative time was shorter for patients with significant SSEP change (131.6 ± 14.7 minutes vs. 146.5 ± 46.7 minutes; P = .048). There were no postoperative positional brachial plexus injuries.

Conclusions: SSEP is a novel, safe, and reliable tool in detection of position-related brachial plexus neuropathy. Intraoperative monitoring using SSEP can play a vital role in early recognition and prevention of injury during robotic transaxillary thyroid and parathyroid surgery.

Level of evidence: 4 Laryngoscope, 129:2663-2668, 2019.

Keywords: Brachial plexus injury; intraoperative nerve monitoring; robotic transaxillary thyroidectomy; somatosensory evoked potentials.