Clinical Study Of The Significance Of Cobb Angle In The Methods Of Operation And Its Efficacy For The Patients With Severe Cervical OPLL

Background and purposeOssification of the posterior longitudinal ligament is one of north common cervical vertebra disease in our country,its severe type can lead to serious stenosis of cervical vertebra tube causing severe compression symptoms of spinal cord and nerve,and can also cause changes in the curvature of the cervical spine(negative K line).Then leading to cervical instability,retroflection,causing the symptoms of the tethered cervical spinal cord.At present,there are many indexes to measure the curvature change of cervical spine,but the measurement of C2-7 cobb angle of this disease is relatively intuitive,simple and easy to measure,with a high degree of clinical application.Therefore,this study aims to measure C2-7 cobb angle to analyze the influence of the change of cervical curvature on the clinical symptoms and surgical efficacy of patients with severe cervical OPLL.MethodsFor cervical myelopathy and/or radiculopathy caused by multilevel-severe OPLL with negative K-Line OPLL,we performed MPAD from 2005-2015 at one institution.A series of 53 patients were evaluated for minimum four years’ follow-up.Among them,there were 36 males and 23 females,aged from 40 to 76 years old,with an average age of(55.94±10.05)years old.The Japanese Orthopaedic Association score was used to assess neurological function before surgery,1,2,3,4 years after surgery.The Visual analogue scale was used to assess the level of pain of the patients before surgery,1,2,4 years after surgery.The C2-7 cobb angle was used to evaluate the cervical curvature of the patients before surgery,1,2,4 years after surgery.ResultsAmong of 59 patients,4 patients died,2 patients’ data were lost in follow-up,and the remaining 53 patients were fully followed up.The follow-up time was all greater than 48 months(48～175),with an average of(108.8±32.5).Japanese orthopedic association score and visual analogue scale score was significant increased at post operation,1 year after operation,2 years after operation,(P<0.001).At 4 years after the operation,the recovery rate of neurological function was(72.75±10.94)%.Preoperative C2-7 cobb angle was significantly correlated with axial symptoms(P<0.01).There was no significant statistical significance between the degree of correction of C2-7 cobb angle during surgery and the occurrence of axial symptoms after surgery(P>0.05).The postoperative recovery rate of JOA increased and then decreased with the increasing of the degree of correction of C2-7 cobb angle.When the correction range of C2-7 cobb angle was 7°～18°,the postoperative recovery rate was ideal(RR>60%).Complications occurred in 9 cases in the study,but no specific complications were identified that were associated with this technique(P>0.05).ConclusionsC2-7 cobb angle has certain guiding significance in the selection of surgical methods and the determination of clinical efficacy in patients with multilevel-severe cervical OPLL with negative K-Line.Modified posterior-anterior approach decompression and bone grafting internal fixation guided by C2-7 cobb angle has achieved good clinical efficacy in the treatment of the patients with multilevel-severe cervical OPLL with negative K-Line.Therefore,the measurement of this angle can be regarded as a simple and practical basis for the clinical diagnosis and treatment of such diseases.