The application of somatosensory evoked potentials in monitoring the occurrence of postural brachial plexus injury in ankylosing spondylitis with thoracolumbar kyphosis following pedicle subtraction osteotomy

English Keywords:Ankylosing spondylitis  Pedicle subtraction osteotomy  Postural brachial plexus paralysis  Somatosensory evoked potentials

English Abstract:

  【Abstract】 Objectives: To investigate somatosensory evoked potentials(SEP) in monitoring the postural brachial plexus injury in ankylosing spondylitis(AS) patients with thoracolumbar kyphosis following pedicle subtraction osteotomy(PSO). Methods: From October 2013 to June 2014, 28 AS patients with thoracolumbar kyphosis and complete SEP data and clinical data undergoing one-level PSO were included in this study. There were 27 males and 1 female. Medium nerve SEP were recorded in all patients. The positive change criteria of the SEP were as follows: the amplitude decreased exceeding 50% to the baseline, and/or the latency delayed exceeding 10% to the baseline. Results: Three patients developing postural brachial plexus injury during surgery were detected by SEP. The amplitude decreased by 100%, 65% and 90% to the baseline respectively. After adjusting the position, 2 patients(the amplitude decreased by 100% and 65%) with the signals of SEP recovered, without the clinical symptom of postural brachial plexus injury after surgery. The patient with SEP amplitude decreased by 90% remained abnormal, and postural brachial plexus injury occurred after surgery. After rehabilitation and medication, the neurological function returned to normal 3 months. Conclusions: The postural brachial plexus injury in AS patients with thoracolumbar kyphosis following PSO can be detected by the medium nerve SEP in time. And the medium nerve SEP will decrease the degree of postural brachial plexus injury in AS patients with thoracolumbar kyphosis undergoing PSO if proper measures are adopted timely.