Postoperative Cauda Equina Syndrome: Report of Two Cases
Cauda equina syndrome is a well-documented complication of uneventful lumbar microdiscectomy. In the vast majority of cases, no radiological explanation can be obtained. In this paper, the authors report two cases of postoperative cauda equina syndrome in patients undergoing single-level de novo lumbar microdiscectomy in which intraoperative electrophysiological monitoring was used. In both patients, the amplitudes of cortical and subcortical intraoperative somatosensory evoked potentials (SSEPs) abruptly decreased during discectomy and foraminotomy. In the first patient, a slow, partial improvement of SSEPs was observed before the end of the operation, whereas no improvement was observed in the second patient. In the first case, clinical findings consistent with cauda equina syndrome were seen immediately postoperatively, whereas in the second one the symptoms developed within 1.5 hours after the procedure. Postoperative magnetic resonance images obtained in both patients, and a lumbar myelogram obtained in the second one revealed no signs of conus medullaris or nerve root compression. Both patients showed marked improvement after an intense course of rehabilitation. The authors' findings support the proposition that intraoperative SSEP monitoring may be useful in predicting the development of cauda equina syndrome in patients undergoing lumbar microdiscectomy. Nevertheless, further prospective clinical studies are necessary for validation of these findings.
In the literature on spinal disorders, the development of postoperative cauda equina syndrome in patients undergoing lumbar discectomy is a well-documented complication. Although the origin of the condition has remained unknown, several theories have been proposed to explain the underlying pathogenetic mechanism. In the vast majority of these cases no explanation based on immediate postoperative MR imaging is usually recognized.
In this communication we report two cases of postoperative cauda equina syndrome that occurred after lumbar microdiscectomy. No abnormalities were seen on the postoperative imaging studies, but significant changes were observed in the intraoperative SSEPs.
Cauda equina syndrome is a well-documented complication of uneventful lumbar microdiscectomy. In the vast majority of cases, no radiological explanation can be obtained. In this paper, the authors report two cases of postoperative cauda equina syndrome in patients undergoing single-level de novo lumbar microdiscectomy in which intraoperative electrophysiological monitoring was used. In both patients, the amplitudes of cortical and subcortical intraoperative somatosensory evoked potentials (SSEPs) abruptly decreased during discectomy and foraminotomy. In the first patient, a slow, partial improvement of SSEPs was observed before the end of the operation, whereas no improvement was observed in the second patient. In the first case, clinical findings consistent with cauda equina syndrome were seen immediately postoperatively, whereas in the second one the symptoms developed within 1.5 hours after the procedure. Postoperative magnetic resonance images obtained in both patients, and a lumbar myelogram obtained in the second one revealed no signs of conus medullaris or nerve root compression. Both patients showed marked improvement after an intense course of rehabilitation. The authors' findings support the proposition that intraoperative SSEP monitoring may be useful in predicting the development of cauda equina syndrome in patients undergoing lumbar microdiscectomy. Nevertheless, further prospective clinical studies are necessary for validation of these findings.
In the literature on spinal disorders, the development of postoperative cauda equina syndrome in patients undergoing lumbar discectomy is a well-documented complication. Although the origin of the condition has remained unknown, several theories have been proposed to explain the underlying pathogenetic mechanism. In the vast majority of these cases no explanation based on immediate postoperative MR imaging is usually recognized.
In this communication we report two cases of postoperative cauda equina syndrome that occurred after lumbar microdiscectomy. No abnormalities were seen on the postoperative imaging studies, but significant changes were observed in the intraoperative SSEPs.