Modified Method Of C3 Laminar Slotting In Cervical Posterior Double Open-door Laminoplasty And Its Clinical Significance

Objective:We aimed to investigate the clinical performance of modified method of C3 laminar slotting in cervical posterior double open door laminoplasty and its clinical significance.Methods:95 patients(including 67 cases of multisegmental cervical spondylosis myelopathy,16 cases of cervical spinal stenosis,and 12 cases of ossification of the posterior longitudinal ligament)were analyzed retrospectively in our hospital from September 2015 to January 2018.Among them,there were 50 males and 45 females,aged 41~82 years,with an average age of 53.8±10.4 years,and the duration of the disease was 17~240 months.All the C3 laminar bone grooves involved in posterior cervical double open door laminoplasty were improved by the method:the upper edge of the C3 laminae was grind off laterally on the basis of a longitudinal bone groove.The way of slotting was"7"or inverted"L".The patients’clinical data were collected:operation time,bleeding volume,intraoperative C3 vertebral plate hinge fracture,postoperative complications(cerebrospinal fluid leakage,incision infection,spring-back closure,C2/3 laminectomy,axial symptoms).The changes of cervical spine JOA score,cervical activity,cervical curvature,C3 level,anteroposterior diameter and area of spinal canal before and after operation were compared.Results:A total of 95 patients underwent posterior cervical double door laminoplasty,including 7 cases of open door decompression and 88 cases of C3-C7.The operative time was 82.3+16.7 minutes,and the bleeding volume was 181.1+50.3 mL.Intraoperative C3 plate hinge fracture occurred in 3 cases(3/95,3.16%).Postoperative JOA score was 14.3+1.5,which was significantly higher than 10.1+2.3 before operation,P=0.001.After operation,the improvement rate of JOA score was 12.8+1.9 mm and 126.2+18.3 mm~2,respectively,which were significantly higher than 7.3+1.2 mm and 78.3+9.1 mm~2 before operation(P=0.001).There was no significant difference in the range of motion and curvature between the cervical spine before and after operation(P>0.05).Postoperative complications(2 cases of cerebrospinal fluid leakage,2cases of incisional infection,0 cases of spring-back closure,0 cases of C2/3 laminectomy and 5 cases of axial symptoms)were cured after active treatment in 1 months after the operation.According to the improvement rate of postoperative JOA score,we judged the improvement of neurological function after operation:excellent in 60 cases,good in 24cases,fair in 10 cases,poor in 1 cases,the excellent and good rate was88.4%.Conclusion:The improved C3 slotting method can safely and effectively expand the C3 lamina by double door opening,which is beneficial to reduce the occurrence of C3 plate hinge fracture.