頚椎後縦靭帯骨化症の手術(<特集>頚椎 OPLL)

抄録

In order to discuss the surgical approaches used in surgery for ossification of the cervical longitudinal ligament (OPLL), we undertook retrospective study of 240 cases with OPLL operated on in the past 17 years. The patients were grouped into 3 categories depending upon the approaches adopted in the operation. Those were anterior decompression group (A), posterior decompression group (P) and combined group (C). In group A, anterior fusion was carried out, after removal of OPLL via the anterior approach. In group P, laminectomy or laminoplasy was performed. In group C, both anterior and posterior decompression were performed in a two stage operation. There were 181 men and 59 women with a mean age of 56.3 years old. Group P had a significantly higher mean age than group A and C. Preoperative neurology indicated that myelopathy had became more severe in group P than in group A and more severe in group C than in group P. Preoperative neuroradiological studies indicated that the OPLL extended longer rostro-caudally in group C than in group A and longer in group P than in group C. CT-myelography (CTM) showed the thickest part of the OPLL in group A was less than 50% of the A-P distance of the spinal canal, while the stenotic ratio was over 50% in group P and C. Extent of anterior fusion was within 2 intervertebral spaces in 78.3% of group A and 60% of group C. Anterior fusion of more than 3 intervertebral space was carried out in 40% of group C. Cervical canal stenosis was complicated in 8.7, 24.6 and 34% in group A, P and C, respectively. Thus it was evident that patients in group A had smaller OPLL and were neurologically less affected compared to group P and C. The operation proved effective in more than 89% of the patients in this group. Neurologically, patients in group C had the severest myelopathy and had larger OPLL than patients of group A. The rostro-caudal extent of OPLL was the largest in group P though myelopathy was less severe than that in group C. Incidence of sequel was 7.6, 4.0 and 18% in group A, P and C, respectively. In group C, all the sequelae were provoked in the anterior approach. Alternative techniques to improve the results among group C patients were discussed. The results suggested that posterior decompression was the safest approach in the surgical management of OPLL.