| Objective: Ossification of the cervical posterior longitudinal ligament (OPLL) has been prevalence in those people whose ages range from 50 to 60, and the disease's incidence ranges from 0.2 to 4% in the population with cervical spine disorders. Because of this disease in Japan in the high population, it also called the "Japan disease." OPLL is characterized by replacement of the ligamentous tissue by ectopic new bone formation and has been recognized as one of the important causes of cervical myelopathy. Patients can be associated with mild to serious neurological complications due to spinal cord or nerve root compression or may be asymptomatic. There is consensus that surgical intervention is usually indicated in these cases who indicated serious complications, but which modus operandi will be the safest and the most effective one is still on sustainable dispute. The surgical treatment of this disease according to operative approach include: anterior surgery, posterior surgery and combined anterior and posterior surgery. The OPLL incorporated with huge protrusion of intervertebral disc or local existence of the significantly thickened ossified mass will lead to seriously oppression in front of the spinalcord,so the simplicity anterior operations'risk on those patients are much high, and once happening it can cause the completeness paralyze, even to die or some other bad results. The key point to the success of the operation is to choose the reasonable and correct surgical approach. The purpose of this study was to investigate the surgical curative effects, complications and indications of posterior unilateral open door laminoplasty combined with anterior interbody fusion, decompression and internal fixation in treating the patients with cervical OPLL, and to evaluate the operative applicability, safety, and efficacy.Methods: This was a study on 68 patients with ossification of cervical posterior longitudinal ligament undergoing the combined posterior-anterior operation in the third affiliated hospital of Hebei medical university. Among the patients, 41 were male and 27 were female, with mean age45.7±13.5 (range from 32 to 85). In anterior decompression, there were 4 cases involving one intervertebral space, 24 cases involving two intervertebral spaces and one centrum vertebrae, and 40 cases involving no less than three intervertebral spaces. They first received posterior unilateral open-door cervical laminoplasty, and then received anterior subtotal vertebrectomy, intervertebral fusion and internal fixation. The operative time interval for both was 7~30(10+ 2.7) d. All the patients received a routine collar fixation for at least two months postoperatively (9.5 weeks on average). According to the Japanese Orthopaedic Surgery Association (JOA score standard), All patients neural function was recorded According to JOA score, and the surgeical complications were recorded, neural improvement rates(rate of the improved JOA score, RIS)were calculated simultaneously. RIS= (postoperative score - Preoperative score) / (17 -Preoperative score)×100%. The curative effect was divided into four classes according to the RIS, excellent: The RIS is above 75%, good: The RIS is 74%~50%, general: The RIS is 49%~25%, bad: The RIS is below 25%. All patients routinely underwent cervical X-ray, CT and MRI examinations before operation, after posterior surgery and combined anterior surgery, all the patients were taken CT and X-ray examinations again. According to the examinations, cervical curvature and the occupied rate of vertebral canal were calculated. During the 3 months, 6 months and one year follow-up period, the X-ray examinations were used to observe if the fusion of the bones graft were gained and if the internal fixation devices loosed or fractured. The clinical curative efficacy, feasibility and safety of the operations were then evaluated according to the improvement of neural function, surgical complication and the manifestation of imaging。Result: The mean JOA score before operation was (6.41 +1.54), the mean JOA score after posterior operation was (9.34+1.82), and the JOA score after anterior operation was (14.68±1.63). T test was used to compare JOA scores. The statistical analysis between pre-operative and pos-operative surgery score by paired t-test indicated a significant difference (P <0.001,α= 0.05). The improvement rates of the twice operationsneurological function were 27.67±18.54% and 78.09±23.73% respectively. After anterior surgery, the neurological function compared with that of after posterior surgery to be improved further. According to the Odom's standard to evaluate the clinical results, excellent: 34 cases, good: 21 cases, general: 11 cases, bad: 2 cases. The rate of good to excellent results was 80.88%. The mean cervical lordosis angle and the occupied rate of vertebral canal were 10.6±7.4o, 53.73±15.46% pre-operatively and 23.6±8.6o, 25.71±12.38% after combined surgery. The statistical analysis by paired t-test indicated a significant difference between pre-operative and pos-operative (P <0.001,α= 0.05). There were three cases with a transient aggravation of the spinal injury and six cases with dura injury which induced cerebrospinal fluid leakage .There were four cases suffering lateral femoral cutaneous nerve injury, which resulted from the incidental injury caused by flank bone taken; five cases with symptoms of cervical 5 nerve root paralysis after the posterior surgery, which only lasted transiently and disappeared after the anterior surgery; three cases was presenting with a thickened ossified mass adjacent to the fused segments and further development on the posterior longitudinal ligament. All the patients were followed up at least for one year (18.8±3.75 months on average). The incidence of the short-term operative complications was 26.5% and that of the long-term operative complications was only 4.4%. All the patients achieved anteriorfusion (the fusion rate was 100%) and the cervical vertebral physiological curvature in all the patients was corrected and maintained in different degrees. there were no spinal cord or nerve root injury, internal fixation fracture and no patients required repeated operation.Conclusion: The posterior-anterior combined operation has provided an alternative operation way for patients with OPLL who might have poor effects by simple anterior approach or simple posterior approach. It can sufficiently decompress the spinal cord, correct the cervical kyphosis, stabilize the cervical vertebrae and reduce the occurrence of the spinal injury during the operation. And it has a good long-term curative effects and low complications of internal fixation and pseudoarticulation formation etc. postoperatively. Therefore the operation improves the safety of the operation. |
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