One-staged release and reduction by posterior approach to treated basilar invagination with irreducible atlantoaxial dislocation / 中华骨科杂志

ABSTRACT

Objective To evaluate the safety and effectiveness of one stage surgery of release and bone reduction by posterior approach to treat basilar invagination (BI) with irreducible atlantoaxial dislocation (IAAD),and to explore the indications and crucial techniques of posterior approach.Methods All of 17 Consecutive patients (8 males and 9 females) with BI and IAAD who underwent release and reduction by posterior approach from July 2000 to June 2015 were enrolled in the present study,the mean age was 35.2±13.8 years with a range of 12-56 years.The clinical symptoms and signs was recorded,and preoperative imaging examination,including anteroposterior,lateral,dynamic films,MRI and CT of cervical spine,were performed to identify the series.There were 14 cases with atlanto-occipital fusion,7 cases with C2,3 fusion,6 cases with Chiari malformation,6 cases with Syringomyelia,and 8 cases with myelomalacia.The clinic symptoms include occiput/neck pain in 15 cases,cervical movement limitation in 13 cases,short neck in 9 cases,torticollis in 12 cases,Paresthesia in 14 cases,weakness in 13 cases,tendon reflexes hyperfunction in 16 cases and ataxia in 13 cases.The postoperative X-rays,MRI or CT were used to observed the results of decompression,fixation and fusion.Neurological function was assessed by JOA scale and Ranawat's score before,after surgery and at final follow-up.Pre-and post-operative Chamberlain (CL),Wackenheim (WL),McGae (ML),atlantodental interval (ADI) and cervico-medullary angle (CMA) were analyzed by student t-test.Results The average operation time was 145 mins (90-210 mins) and blood loss was 175 ml (150-350 ml).The average follow-up was 44.47 months (9-94 months).JOA score was increased from 8.06 preoperatively to 15.20 postoperatively,the improvement rate was 77.2％.Preoperative Ranawat's score was Ⅱ in 1 case,Ⅲla in 12 cases,ⅢB in4 cases.Postoperative score was Ⅰ in 13 cases,Ⅱ in 4 cases.The preoperative CL,WL,ML,ADI and CMA were (12.52±5.17) mm,(6.59±3.04) mm,(6.96±4.32) mm,(9.88± 1.93) mm,115.35°± 12.40°,respectively.and the postoperative CL,WL,ML,ADI and CMA were (2.0±3.67) mm,(-3.06±1.85) mm,(-1.76±2.88) mm,(1.17± 1.18) mm,136.76°±11.44°,respectively.The perioperative complications were discovered in 2 cases,including 1 case of infection and1 case of cerebrospinal fluid(CSF) leakage.Conclusion Primary surgery of nerve release and bone reduction by posterior approach may be safe and efficient for the treatment of BI and IAAD.Preoperative evaluation,proper surgical indications and advanced surgical techniques are important for treatment results.