ABSTRACT
STUDY DESIGN: This study is a prospective review of all spinal cord monitoring procedures in our unit from 1999 to 2004 in patients undergoing spinal deformity correction surgery. OBJECTIVE: To report the sensitivity and specificity of transcranial motor-evoked potentials (MEP) and compound muscle action potential (CMAP) monitoring as the sole modality in spinal deformity correction surgery. SUMMARY OF BACKGROUND DATA: Combined spinal cord monitoring with somatosensory-evoked potentials and MEP has been widely used. The use of CMAP as the only modality has not been widely used and its efficacy has not been fully elucidated. METHODS: The intraoperative monitoring outcomes were compared with patient's postoperative clinical outcomes. The sensitivity and specificity were calculated and determined for our monitoring protocol. RESULTS: Transcranial MEPs were measured in 144 patients in 172 procedures. In 2 patients (3 procedures), we were unable to record any CMAPs. There were 15 intraoperative monitoring changes. There were no new postoperative neurological deficits. CONCLUSION: The monitoring criteria are sufficiently strict to achieve a sensitivity of 1.0 and a specificity of 0.97. Monitoring of CMAPs alone has been adequate to avoid clinical neurological deficits.
Subject(s)
Action Potentials , Evoked Potentials, Motor , Monitoring, Intraoperative/methods , Muscle, Skeletal/physiopathology , Orthopedic Procedures/adverse effects , Spinal Cord Injuries/physiopathology , Spinal Cord/physiopathology , Spine/surgery , Adolescent , Adult , Child , Child, Preschool , Electric Stimulation , Electromyography , False Negative Reactions , False Positive Reactions , Female , Humans , Laminectomy/adverse effects , Male , Muscle, Skeletal/innervation , Predictive Value of Tests , Prospective Studies , Reoperation , Sensitivity and Specificity , Spinal Cord Injuries/diagnosis , Spinal Cord Injuries/etiology , Spinal Fusion/adverse effects , Spine/abnormalities , Treatment OutcomeABSTRACT
A 7-year-old girl having posterior spinal fusion for Grade 3 anterior spondylolisthesis at the L5/S1 level was administered 2.5 mg of morphine in 10 ml saline via the caudal epidural route before surgery. Motor-evoked responses were markedly diminished in her lower limbs for 1 h following this but returned spontaneously. She suffered no neurological injury. The cause for this is postulated to be transient cauda equina compression from the volume of injectate. This complication of caudal injection has not been reported before. The possible mechanisms for this are discussed. We believe that significant L5/S1 spondylolisthesis should be considered a contraindication to the use of caudal epidural injections.
