The Clinical Study Of Treating Chiari Malformation With Atlantoaxial Subluxation By Posterior Decompression And Internal Fixation

Objective: To investigate effects of treatingChiari malformation with atlantoaxial subluxation by posterior decompression and internal fixation Methods:30 patients who were diagnosed as Chiari malformation with atlantoaxial subluxation were analyzed retrospectively at the Department of Neurosurgery,the First Affiliated Hospital of Anhui Medical University between January,2015 and July,2017.They were divided into two groups: the posterior decompression with internal fixation group(n=14)and the posterior decompression without internal fixation group(n=16).We recorded the operation time,intraoperative blood loss,bed resttimeafteroperation and the time before being discharged.The patients were also evaluated the condition based on the Japan Orthopedic Association(JOA)score and MRI which was used to measure the degree of cerebellar tonsil herniation pre-and post-operations.T-test was used toanalyze.Results: There was no difference on ages or sex of patients in two different groups.All 14 patients were successfully placed with screws without vertebral artery injury or cerebrospinal fluid leakage.The internal fixation group operation time(177.86 ± 9.94 min)was longer than the non-internal fixation group operation time(129.06 ± 10.68 min,t = 5.685,P <0.01).Intraoperative blood loss in the internal fixation group(303.57±66.40 ml)was more than that in the non-internal fixation(168.75±62.92 ml,t=-12.952,P<0.01).The internal fixation group bed rest time after operation(8±4d)was shorter than that in the non-internal fixation group(12 ± 5d,t =-2.712,P =0.03).The internal fixation group the time before being discharged(11±3d)was shorter than that in the non-internal fixation group(15 ± 5d,t = 3.215,P =0.04).Compared with preoperative,JOA score and differences in length of cerebellar tonsil herniation in the internal fixation group was higher than that in the non-internal fixation group(3.21 ± 1.05 vs 2.37 ± 0.88,t = 2.437,P = 0.027,0.51 ± 0.11 cm vs 0.32 ± 1.33 cm,t=-4.411,P <0.01),respectively.All the internal fixation sites were satisfied.During the follow-up period,no internal fixation devices were loosen,fallen off and no broken nail.The fusion rate of bone graft was 100%.30 patients were followed up for 6 to 30 months(12.5±4.2 months).Conclusion: Direct posterior decompression and internal fixation with posterior cranial fossa cranioectomy decompression can obviously improve the clinical outcomes and shrink syrinx for patients suffered from Chiari malformation with atlantoaxial subluxation.