Position-related neurovascular injuries detected by intraoperative monitoring

Background: Poor patient positioning during surgeries can result in vascular and peripheral nerve injuries. The purpose of this study was to analyze the various etiologic factors related to positioning detected by intraoperative monitoring (IOM) and make recommendations for prevention of comorbidities. Materials and Methods: The data for a total of 4450 consecutively monitored patients who underwent orthopedic and neurosurgical procedures were retrospectively reviewed. Patients with signal changes related to positioning detected by IOM were analyzed for position, modalities, timing of interventions, duration of surgery, and etiologic factors. Deficit and non-deficit groups were further compared using Wilcoxon rank sum test. Results: Intraoperative evidence of impending neurologic injury was seen 1.1% times, most frequently due to malpositioning of upper extremities (57%) in prone position (55%). Shoulder tape, bootstrap, thigh/hip pads, sitting and lower extremity malpositioning were other etiologic factors. Appropriate intervention was performed within 3min 66% of the time. Four patients developed new postoperative deficits: brachial plexopathy (n = 3) and bilateral sciatic neuropathy (n = 1). The deficit group had longer duration of surgery (P = 0.031), and neurophysiological (NP) signal changes persisted for an increased time interval (P = 0.0084) when compared to the non-deficit group. Conclusion: Prolonged duration of surgery and persistence of NP signal changes can increase the risk of potential neurovascular injury. Intraoperative neurovascular injuries due to positioning can occur in various settings. Early recognition of signal changes during monitoring and immediate intervention is likely to prevent neurological deficits.