Revision surgery for patients after inappropriate posterior fossa decompression for craniocervical junction malformation

Abstract

Objective To evaluate the revision surgical techniques with intraoperative CT navigation system for the treatment of craniocervical junction malformation after inappropriate excessive posterior fossa decompression.Methods 12 patients with Chiari Ⅰ malformation,basilar invagination and syringomyelia,after extensive posterior fossa decompression received the revision surgery from April 2009 to March 2012.The clinical presentation,treatment and follow-up results of the patients were retrospectively studied.Results The 12 patients included 5 females and 7 males.The mean age was 37.4 years.The most common symptom was motor deficit in 12 patients.Syringomyelia occurred in 8 patients.Three patients got cerebellar ptosis.8 patients were performed the posterior fixation and fusion in a reduced position with the intraoperative CT and neuronavigation.4 patients with irreducible craniovertebral junction were only performed the posterior occipitocervical fixation,whereas 1 patient was performed the posterior occipitocervical fixation,and a transoral odontoidectomy was performed as the second procedure.During 9-24 months of follow-up,solid bone fusion was observed between the occipital bone and axis in all patients.The syringomyelia in 7 patients was improved.The cerebellar ptosis of 3 patients was resolved.The range of McCormick grade was Ⅰ-Ⅲ and the range of 6 months postoperative KPS score was 80-100.Conclusions It was necessary that simultaneous fixation and fusion after an appropriate posterior decompression in patients of basilar invagination associated with Chiari malformation.The revision occipitocervical fixation and fusion with the intraoperative CT and neuronavigation for the treatment of craniocervical junction malformation after inappropriate excessive posterior fossa decompression could be successfully performed. Key words: Arnold chiari malformation type Ⅰ; Fixation; Neuronavigation; Intraoperative computed tomography