Abstract
Introduction
It is widely known that laminoplasty (LP) and anterior cervical fusions have been performed for ossification of posterior longitudinal ligament (OPLL). But progression of kyphosis and development of the ossification after surgery sometimes cause aggravation and revival of the symptoms. Recently, several authors reported that posterior cervical spinal fusion (PSF) for patients with OPLL. The purpose of this study is to assess surgical outcome of the selective spinal fusions for OPLL in the cervical spine.
Method
From 2010 to 2014, twenty seven patients with OPLL (mean age 68 years) who underwent surgical treatment with LP (14 patients) or PSF (13patients) were included in this study. Surgical outcomes were assessed by operative time, amount of bleeding and complications. Radiographic measurement included change of the alignment in C2/C7 (cervical lodosis), range of motion of cervical spine. Neurological function was assessed using a Japanese Orthopaedic Association Scale (JOA).
Result
Mean follow-up period is one year. The operative time was slightly longer in PSF group, but amount of bleeding was not significance. One patient had C5 paralysis in PSF group. In fixed range at PSF group, one interbody fixation was three cases, two fixations were seven cases and three fixations were three cases. On radiographic analysis, the mean change of alignment at last follow-up period were 2.8° ± 6.5° (LP) and 1.6° ± 6.9° (PSF). Range of motion of cervical spine were 8.6° ± 9.6° (LP) and 9.9°±7.6°(PSF). There was not significant difference between two groups at pre-operative JOA score. Improvement rate of JOA score were 55.7% ± 32.2% (LP) and 42.3% ± 25.4% (PSF). There was no significant difference between both groups in all categories.
Conclusion
It is natural to preserve as much as possible mobility in cervical spine. On the other hand, there is another opinion that instability of the cervical spine at boundary of ossification zone is related to development of ossification. It may prevent ossification to obtain stability of the cervical spine. In comparison with the LP, PSF did not adversely affect the clinical and radiographic outcomes in this study. This result suggested the possibility that PSF maintains a function of the cervical spine and prevents ossification. Limitation of our study include the short follow-up period and various fixed range. It is necessary to observe long-term progress.