Detection of positional brachial plexus injury by radial arterial line during spinal exposure before neuromonitoring confirmation: a retrospective case study

To demonstrate the potential usefulness of radial arterial line monitoring in detection of brachial plexus injury in spinal surgery. Multiple neuromonitoring modalities including SEPs, MEPs and EMG were performed for a posterior thoracicolumbar surgery. Radial arterial line (A-line) was placed on the right wrist for arterial blood pressure monitoring. Reliable ulnar nerve SEPs, hand muscle MEPs and arterial blood pressure readings were obtained after patient was placed in a prone position. A-line malfunction was noted about 15 min after incision. Loss of ulnar nerve SEPs and hand muscle MEPs with a cold hand on the right was noticed when neuromonitoring resumed after spine exposure. SEPs, MEPs, A-line readings and hand temperature returned after modification of the right arm position. Radial arterial line monitoring may help detect positional brachial plexus injury in spinal surgery when continuous neuromonitoring is interrupted during spine exposure in prone position.