Masashi Komagata

Treatment of myelopathy due to cervicothoracic OPLL via open door laminoplasty.

Study Design Postoperative long-term follow-up study of open door laminoplasty for the ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine. Objectives Techniques and outcomes of open door laminoplasty were described. The efficacy of this procedure was discussed and compared with other surgical methods for thoracic OPLL reported in the literature. Summary of Background Data OPLL of the thoracic spine is often associated with cervical OPLL or ossification of the yellow ligament (OYL) of the thoracic spine; therefore, it is extremely difficult to determine the most appropriate surgical therapeutic procedure. There are very few detailed reports about extensive laminoplasty for OPLL of the thoracic spine. Methods The subjects included in this study consisted of 13 consecutive patients of thoracic OPLL who were surgically treated between 1994 and 2003 by the open door laminoplasty using the spinal processes and ligament complex as spacers for the open side. The number of manipulated lamina, including the cervical spine, was from 7 to 14 (mean 10 laminae), the follow-up period was 75 months on average. We evaluated the clinical symptoms by the JOA scoring method and postoperative bone union and thoracic kyphosis by plain x-ray photograph and computed tomography. Results Postoperatively, the JOA score improved from an average of 5.5 to 8.5 out of a maximum of 11 points and the mean recovery rate by Hirabayashi method was 54.5%. In all cases, bone union was seen at the hinge side between the opened lamina and the lateral mass. Neither restenosis of the opened lamina nor marked progression of kyphosis were seen on the final follow-up observation in any patient. There was no postoperative spinal cord injury. Conclusions Open door laminoplasty is a useful procedure for OPLL of the thoracic spine. This method enables wide-range posterior decompression, especially for the continuous type OPLL extending from the cervical spine to the thoracic spine, even if the apex of the thoracic kyphosis is included.

INCREASES IN COX II mRNA IN THE RAT SPINAL CORD INDUCED BY CAUDA EQUINA TRACTION

This article investigated the time response of COX II induction by traction of the cauda equina assessed by a quantified RT-PCR method. Under deep GOI anesthesia, male Wistar rats were fixed in the prone position and a laminectomy of the dorsal part of the first and second sacral vertebrae was performed. Following, COX II-mRNA levels in the cervical, thoracic, lumbar, sacral, and caudal segments were measured at 2, 4, 6, and 24 h after traction by a quantified RT-PCR method. After cauda equina traction, significant levels of COX II mRNA were detected in all segments of the spinal cord examined. Maximum levels in each segment were determined 4 h after traction of the cauda equina. Particularly in the sacrocaudal segments significantly higher levels of COX II mRNA were measured 24 h after traction. These results indicate that significant induction of spinal COX II mRNA was caused by cauda equina traction and that such induction plays a regulatory role in the nociceptive pain pathway.