Surgical Treatment And Outcomes Of Ossification Of Posterior Longitudinal Ligament Of Cervical Spine

Objective:To observe and analyse the results of ossification of posterior longitudinal ligament(OPLL)of cervical spine with different surgical approaches. Discuss the operation methods and outcomes for the OPLL patients and evaluate the influence of the rate of spinal stenosis,cervical curvature, types and ranges of OPLL and the increased signal intensity (ISI) of the spinal cord on T2-weighted MRI.Methods:The clinic data of 127 patients from 2003 to 2007 with cervical OPLL were reviewed and analyzed, age of 41 to 70 years, average 55.2 years old, which involved 61 men and 66 women, were respectively decompressed from anterior and posterior approaches. Patients were followed up for 3 to7 years,3.8 years on average. Lateral cervical spine X ray, flexion film had held out, CT scan, sagittal reconstruction, and MRI examinations were routinely taken pre operatively. Results of operations according to JOA scoring system, which was formulated by Japanese Orthopaedic Association, were evaluated. Neurological function was evaluated on pre operatively,and 1w, 1y,3y, post operatively,and the early(1w) and final(3y) neural improvement rates (rate of the improved JOA score, RIS) were also calculated. The data was evaculated by SPSS13.0 analysis software. The difference was statistical significance when P<0.05. Surgical complications and factors affecting the surgical results were also recorded.Results:1.The cervical curvature in the anterior operation group was better improved and maintained in long-term evaluation than the posterior group.2. The lower RIS was observed in the patients with higher rate of spinal stenosis. In short-term effect, there was no significant difference between anterior and posterior approach, but in long-term effect, anterior approach was better than posterior approach, when the rate of spinal stenosis was less than 50%. When it was more than 50%～60%. anterior approach led to better effect.3. In the lordosis group, there was no significant difference between anterior and posterior approach in short-term effect, but in long-term effect, anterior approach was better. In the Straight and kyphosis group,anterior approach had better effect than posterior approach.4. Anterior approach had better effect than posterior approach when the range of the OPLL was no more than two segments. When the range was no less than three segments, anterior approach was better than posterior approach in long-term effect,and there was no significant difference between them in short-term effect.5. In the solitary and segment OPLL group,anterior approach had better effect, and in the continuous and mixed OPLL group the effect of anterior approach was better than posterior approach in long-term effect,and the two were similar in short-term effect.6. The higher RIS was observed in the patients without ISI than the ISI group and the difference was significant. In the group without ISI, anterior approach had better effect than posterior approach in long-term follow-up. In the ISI group, there was no significant difference between anterior and posterior approach in short-term effect, but in long-term effect, anterior approach had better effect and RIS.Conclusions:The considerable factors that influence the outcomes of OPLL include the rate of spinal stenosis, cervical curvature, types and ranges of OPLL and the ISI, which are also significant to the surgery strategies of OPLL.1.Better prognosis is performed in the OPLL patients with lower rate of spinal stenosis.In spite of the increase of operational difficulty and the risk of complications, anterior approach is better than posterior approach especially in long-term effect.2.The anterior operation can improve the cervical curvature, which can be maintained in long-term follow-up. The OPLL patients with cervical straight and kyphosis can be decompressed by the anterior operation and fussion,which reconstructs cervical curvature and stability.3. Anterior operation has better effect on the limit-range OPLL, and on the long-range OPLL excluding the C2,C7 segments, anterior approach was better than posterior approach in long-term follow-up.4. Anterior decompression has better effect on the solitary and segment OPLL, and posterior decompression has little effect to prevent the growth of ossification in continuous and mixed OPLL.5. Better prognosis is observed in the OPLL patients without ISI. In the patients with ISI, complete decompression can be achieved by anterior operation and better effect is confirmed in long-term follow-up.The posterior-anterior approach was a safer choice in the patients with severe spinal stenosis.