title: Postoperative cauda equina syndrome in patients undergoing single-level lumbar microdiscectomy. Report of two cases.
abstract: 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.
authors.affiliation: Department of Neurosurgery, Medical Center of Central Georgia, Macon, Georgia, USA.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Dimopoulos
authors.forename: Kostas N
authors.initials: KN
authors.lastname: Fountas
authors.forename: Theofilos G
authors.initials: TG
authors.lastname: Machinis
authors.forename: Carlos
authors.initials: C
authors.lastname: Feltes
authors.forename: Induk
authors.initials: I
authors.lastname: Chung
authors.forename: Kim
authors.initials: K
authors.lastname: Johnston
authors.forename: Joe Sam
authors.initials: JS
authors.lastname: Robinson
authors.forename: Arthur
authors.initials: A
authors.lastname: Grigorian
mesh_terms: D000328:Adult; D017586:Diskectomy / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008866:Microsurgery / Q000009:adverse effects* / Q000379:methods; D008875:Middle Aged; D011128:Polyradiculopathy / Q000000981:diagnostic imaging* / Q000209:etiology; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011859:Radiography