Decreasing the prospect of upper extremity neuropraxia during robotic assisted laparoscopic prostatectomy: a novel technique

Risk of intraoperative neuropathic injury in minimally invasive surgery has been established as a leading complication. Continuous intraoperative neuromonitoring (IONM), such as upper extremity somatosensory evoked potentials (ueSSEPs), to decrease peripheral nerve injury due to positional stress has been described. Robotic-assisted laparoscopic prostatectomy (RALP) requires steep Trendelenberg, which may predispose patients to upper extremity neuropraxia. Subdermal stimulating electrodes were placed on the patients’ bilateral wrists over the ulnar nerve and the nerve was stimulated. Realtime waveforms were compared to baseline data to prevent and detect injury to the ulnar nerve. Established intervention criteria, indicating risk for neuropathic damage necessitating intraoperative patient repositioning, was a 50% loss in amplitude or a 10% increase in latency. One hundred and forty three patients received RALP with IONM. 17 of 143 patients (11.8%) met ueSSEP intervention criteria. Only weight was significantly different between the two groups (p = 0.04). Mean reduction in amplitude was 79.9% (SE 4.1). Average amplitude loss duration was 22 min (SE 4.0). Weight and BMI were correlated to the degree of amplitude reduction (p = 0.03 and < 0.01), while operative time and DM approached significance (p = 0.09 and p = 0.14). This is the first study to use IONM to reduce the risk of nerve injury during genitourinary surgery. Realtime nerve monitoring using ueSSEP allowed for upper extremity intraoperative monitoring and repositioning. This may decrease the risk of upper extremity neuropraxia due to malpositioning during RALP. Weight and BMI were identified as risk factors for possible nerve injury. Further data collection and analysis to preoperatively stratify patients for application of IONM during RALP is currently ongoing.