The outcomes of modified laminplasty through posterior paraspinal approach compared with traditional laminplasty using posterior midline approach in the treatment of patients with cervical ossification of the posterior longitudinal ligament

English Keywords:Ossification of the posterior longitudinal ligament  Cervical laminoplasty  Cervical posterior intermuscular paraspinal approach  Outcomes

English Abstract:

  【Abstract】 Objectives: To compare the clinical outcomes of modified laminplasty through posterior paraspinal approach and traditional laminplasty using posterior midline approach in the treatment of patients with cervical ossification of the posterior longitudinal ligament(OPLL). Methods: 32 patients with cervical OPLL at our hospital between June 2011 and September 2014 were treated by posterior laminplasty. Of all patients, 14 were of the modified laminplasty group as Group A(mean age, 56.9 years; range 42 to 70 years), and 18 were of the traditional laminplasty group as Group B(mean age, 56.7 years; range 40 to 73 years). There were no differences in age, gender, spinal cord compression levels and surgical levels between the two groups(P＞0.05). The operation time, blood loss, postoperative complications were recorded. The visual analogue scale(VAS), neck disability index(NDI), short form 36 questionnaire(SF-36) and Japanese Orthopedic Association(JOA) scores were recorded before operation, and 3 months, 1 year and, 2 years postoperative and at the last follow-up. The cervical sagittal alignment, cervical range of motion(ROM) for C2-C7 were measured by cervical X-ray radiographs before operation, and 3 months, 1 year and, 2 years postoperative and at the last follow-up. The area of cervical extensors was measured by MRI before operation and at the last follow-up, and the atrophy ratio were calculated. Results: All patients were followed up. The follow-up time is 59.4±4.2 months in group A, and 61.4±3.8 months in group B. There was no difference between the two groups(P＞0.05). Besides, there was no difference in postoperative drainage between the two groups(P＞0.05). All patients had an improvement of neurological function without serious complications in both groups, but group A had longer operation time(197.0±28.9min vs 149.0±25.3min) and more blood loss(339.0±183.1ml vs 277.0±171.4ml) compared to group B(P<0.05), while group A had a lower rate of axial pain (14.3% vs 38.9%) compared to group B(P<0.05). In both groups, the JOA, VAS, NDI and SF-36 scores at 3 months, 1 year, 2 years after operation and last follow-up were all improved compared with preoperation. At the follow-up of 1 and 2 years, the JOA scores of the two groups increased significantly compared with preoperation(P<0.05), but at the last follow-up, the JOA scores of the two groups decreased, and in group B the difference was statistically significant(P<0.05). There were no differences in JOA, VAS, NDI and SF-36 scores before operation. At 1 year, 2 years postoperative and last follow-up, NDI and SF-36 scores of group A were better than group B significantly(P＜0.05). There were no differences in JOA scores at 3 months, 1 year, 2 years postoperative between the two groups. However, at the last follow-up, the JOA scores in group A was better than group B significantly(P＜0.05). At postoperative 3 months, 1 year, 2 years and last follow-up, the C2-7 Cobb angle of group B significantly decreased than that before operation (P＜0.05). At postoperative 1 year, 2 years and last follow-up, there were significant difference in C2-7 Cobb angle between the two groups (P＜0.05). In both groups, the cervical ROM at the follow-up 3 months, 1 year, 2 years and last follow-up were all decreased compared with preoperation(P<0.05), and the difference was statistically significant between the two groups at 3 months, 1 year, 2 years and the last follow-up(P<0.05). There were significant differences in cervical extensors atrophy rate of both sides between the two group at the last follow-up[(28.3±4.8)% vs (41.6±9.2)%, P<0.05]. Conclusions: The modified laminplasty through posterior paraspinal approach and traditional laminplasty using posterior midline approach in the treatment of patients with cervical OPLL had a similar outcome in improving neurological function. But there were lesser axis symptom rate, higher life quality, better cervical alignment, lesser decrease in neurological function in modified laminplasty compared to traditional laminplasty.