Progression Of Ossification Of The Posterior Longitudinal Ligament Research Articles

Multicenter study investigating the postoperative progression of ossification of the posterior longitudinal ligament in the cervical spine: a new computer-assisted measurement

Ossification of the posterior longitudinal ligament (OPLL) often progresses after surgery, and this may cause late-onset neurological deterioration. There have been few studies, however, to clarify any correlation between progression and clinical outcome, partly because of the lack of studies involving reliable and reproducible methods by which detection of progression is made possible. The authors conducted a multicenter study to investigate the occurrence of postoperative progression and to elucidate the possible risk factors in a large-scale patient population, and a novel computer-assisted measurement method was used to provide the basis for future clinical studies. The authors analyzed lateral plain radiographs obtained immediately and at 1 and 2 years after surgery in 131 patients who underwent posterior decompression at 13 institutions. The x-ray films were transformed via scanner into digital images; the length and thickness of ossifications were measured using a new computer-assisted measurement system, and the incidence of progression was determined. Odds ratios for progression according to age group and types of OPLL were determined and compared to elucidate significant risk factors of progression. This is the first multicenter study to investigate the incidence of OPLL progression after posterior decompression by using a standardized measurement method. The rate of postoperative progression at 2 years was 56.5%, which was comparable with results reported in other studies. Progression occurred more frequently in younger-age rather than in older-age patient populations at both 1 and 2 years postoperatively. Mixed-type and continuous-type OPLL progressed more frequently than the segmental-type lesion at 2 years. The results of the present study could serve as basis for future studies to assess the efficacy of drug therapy to prevent OPLL progression.

Long-term results of expansive laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine: more than 10 years follow up

The authors report the long-term (more than 10-year) results of cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine as well as the factors affecting long-term postoperative course. The authors reviewed data obtained in 92 patients who underwent cervical laminoplasty between 1982 and 1990. Three patients were lost to follow up, 25 patients died within 10 years of surgery, and 64 patients were followed for more than 10 years. Results were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy. The recovery rate was calculated using the Hirabayashi method. The mean neurological recovery rate during the first 10 years after surgery was 64%, which declined to 60% at the last follow-up examination (mean follow up 12.2 years). Late neurological deterioration occurred in eight patients (14%) from 5 to 15 years after surgery. The most frequent causes of late deterioration were degenerative lumbar disease (three patients), thoracic myelopathy secondary to ossification of the ligamentum flavum (two patients), or postoperative progression of OPLL at the operated level (two patients). Postoperative progression of the ossified lesion was noted in 70% of the patients, but only two patients (3%) were found to have related neurological deterioration. Additional cervical surgery was required in one patient (2%) because of neurological deterioration secondary to progression of the ossified ligament. The authors performed a multivariate stepwise analysis, and found that factors related to better clinical results were younger age at operation and less severe preexisting myelopathy. Younger age at operation, as well as mixed and continuous types of OPLL, was highly predictive of progression of OPLL. Postoperative progression of kyphotic deformity was observed in 8% of the patients, although it did not cause neurological deterioration. When the incidence of surgery-related complications and the strong possibility of postoperative growth of OPLL are taken into consideration, the authors recommend expansive and extensive laminoplasty for OPLL.

Radiological Study of Cervical Ossification of the Posterior Longitudinal Ligament

The rate of progression of cervical ossification of the posterior longitudinal ligament (OPLL) was radiologically studied during a 3-year period in three patient populations: (a) after laminoplasty (25 patients), (b) after laminectomy (16 patients), and (c) in patients who were managed without surgery (56 patients). There appeared to be no significant difference between these two surgical procedures in postoperative progression of OPLL. When progression of OPLL was compared between patients treated surgically and nonsurgically, posterior surgery accelerated progression of OPLL.

Radiological Study of Cervical Ossification of the Posterior Longitudinal Ligament

The rate of progression of cervical ossification of the posterior longitudinal ligament (OPLL) was radiologically studied during a 3-year period in three patient populations: (a) after laminoplasty (25 patients), (b) after laminectomy (16 patients), and (c) in patients who were managed without surgery (56 patients). There appeared to be no significant difference between these two surgical procedures in postoperative progression of OPLL. When progression of OPLL was compared between patients treated surgically and nonsurgically, posterior surgery accelerated progression of OPLL.

頚椎後縦靭帯骨化症の手術症例における骨化進展

Ninety-four patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine who had been treated operatively were evaluated clinically and radiologically. Anterior fusion, laminectomy, cervical enlargement surgery was carried out on 33 cases, 18 cases, 43 cases respectively. Radiological progression of OPLL was seen in 36% of anterior fusion, 100% of laminectomy, 81% of enlargement. In the postoperative evaluation, anterior fusion was found to be effective in 64%, laminectomy 61%, and enlargement 70%. There was no obvious correlation between post-operative result and progression of OPLL after operation.