To Evaluate Clinical Effects Of Using The Posterior Fossa Decompression With The Bone Graft Fusion And The Internal Fixation To Therapy The Chiari Ⅰ Malformation With The Basilar Invagination

Objective(s):To evaluate clinical effects of using the posterior fossa decompression with the bone graft fusion and the internal fixation to therapy the Chiari I malformation with basilar invagination. To provide the reference for clinical therapy.Methods:To retrospectively analysis 27 patients with the Chiari I malformation and basilar invagination operated by the posterior fossa decompression with the bone graft fusion and the internal fixation, collected in the Neurosurgery Department of The First Affiliated Hospital of Kunming Medical University from September 2011 to September 2015. There were 14 men and 13 women, ranging froml3 to 57 years old, with the average of 37.A11 patients showed different degrees of clinical syndrome and sign. Pre-operation imaging showed the odontoids inbursted foramen magnum, and the tips of odontoids extended above the chamberlain line ranging from 6 to 20mm, with the average of 11.6±2.95mm.The cerebellar tonsil surpassed foramen magnum ranging from 6 to 15 mm,with the average of 9.8±3.87mm,resulting in obviously compression of the spinal cord from the ventral and back aspect.The cervicomedullary angle (CMA) of all patients were 111°-148°, with the average of 131.577°±6.467,The clivus centrum angle (CCA) of all patients were 104°-141°, with the average of 120.692°±7.821°.The JOA (Japanese Orthopedic Association) scores of preoperation were 7-12, with the average of 8.962±1.182.A11 patients operated by the appropriate skull traction in the operation and the posterior fossa decompression of the small skull window combine with the bone graft fusion and the internal fixation, thirteen of them operated by the posterior fossa decompression with the atlato-occipital fascia neurolysis and resection of endocranium outer (PFD),fourteen of them operated by the posterior fossa decompression duraplasty (PFDD).To measure parameters of these patients on the CMA,CCA according to each patient imaging data and the JOA scores which it was used for evaluating spinal cord function of each patient before and after operation,compared they with paired T test statistics.To statistic the average hospital stay after surgery,intraoperative average blood loss,the average time of operation and compare the improvement ratio of syringomyelia,postoperative complication and the efficient of the JOA scores with χ2 test statistics.Results:After surgery, one patient appeared the intracranial infection, two patients arised the infection of wound, one patient appeared cerebrospinal leak, one patient died in the respiratory failure.The hospital stay after surgery were 4-60 days, with the average of 18.7±12.2 days,26 patients were achieved satisfied followed-up.The followed-up time of all patients ranged from 6 months to 40 months, with the average of 15.5 months. Graft-bone fusion of all patients were successful.One of them arise the internal fixations loose.One of them appeared the hydrocephalus,CMA was added from131.577°±6.467°reoperatively to 142.615°±7.788°,The CCA was added from 120.692°±7.821°reoperatively to 133.308°±8.921°,The JOA scores was increased from 8.962°±1.182° preoperatively to 12.654°±2.226°ostoperatively.The improve-ement ratio of syringomyelia was 54.2%,the improvement ratio of clinical efficacy reach 66.7%.There are statistically significant difference with paired T test statistics in the CCA,CMA and the JOA scores before and after the operation.PFD:the average time of operation was 5.6h, the intraoperative average blood loss was 184.6ml, average of hospital stay after surgery were 15.2d,the ratio of postoperative compli-cation was 5.4%,the improvement ratio of syringomyelia was 27.3%,The efficient of the JOA scores was 38.5%.PFDD:the average time of operation was 6.5h, the intraoperative average blood loss was 271.2ml, average of hospital stay after surgery were 22.1d,the ratio of postoperative complication was 42.8%,the improvement ratio of syringomyelia was 76.9%,The the efficient of the JOA scores was 92.9%.there are statistically significant difference with χ2 test statistics in the improvement ratio of syringomyelia and the efficient of the JOA scores,which means that the PFDD was better than the PFD.there is no significant difference with χ2 test statistics in the ratio of postoperative complication.Conclusion(s):1. The posterior fossa decompression of the small skull window combine with the bone graft fusion and the internal fixation is a safe and effective method for the Chiari I malformation and basilar invagination.It is necessary for appropriate skull traction in the operation to adjust the atlato-occipital malformation.2. It is good for the improving of syringomyelia and clinical effects to treat the the Chiari I malformation with the basilar invagination by the posterior fossa decompression enlarged-duraplasty.