Microsurgical transdural discectomy with laminoplasty - New treatment for paracentral and paracentroforaminal cervical disc herniation associated with spinal canal stenosis

Design. A clinical study of the surgical procedure for cervical disc herniation was conducted. Objectives. To describe microsurgical transdural discectomy with laminoplasty, and to assess the clinical outcome of this surgical technique. Summary of Background Data. A posterior approach for cervical disc herniation has been considered risky, and few reports on a transdural approach to this disorder have appeared in the past decade. However, a transdural approach with recent innovations (a microsurgical technique, intraoperative spinal cord monitoring, and laminoplasty) has not been reported, Methods. For this study, 30 patients with myelopathy or radiculomyelopathy accompanied by cervical disc herniation, aged 30 to 77 years (mean, 55 years), underwent microsurgical transdural discectomy with laminoplasty. Preoperative images showed multisegmental disc degeneration, developmental canal stenosis, or both for all the patients. The intraoperative evoked spinal cord potentials were recorded for neurophysiologic assessment. The follow-up period averaged 52 months (range, 24-118 months). Results. The operative time averaged 239 minutes (range, 160-340 minutes), and the mean blood loss was 169 mL (range, 30-701 mL). The Japanese Orthopedic Association score improved from 3.5 to 15 (mean, 11.4) before surgery to 9 to 17 (mean, 15.2) after surgery. The intraoperative evoked spinal cord potentials indicated the affected spinal cord level and reflected the severity of myelopathy. Postoperative cerebrospinal fluid leakage, pseudomeningocele, and progression to cervical deformity were not observed. Transient palsy of the C5 nerve root was observed in two patients with C4-C5 central cervical disc herniation. Conclusions. Microsurgical transdural discectomy with laminoplasty can be performed safely as a selected surgical option for paracentral and paracentroforaminal cervical disc herniation with multisegmental canal stenosis.