Experience of 37 cases of microsurgical treatment of Chiari type I malformation

Abstract

Objective To investigate the clinical efficacies and complications of different surgical methods for the treatment of Chiari typeⅠmalformation. Methods The clinical dates of 37 patients with Chiari typeⅠmalformation admitted to neurosurgery department of the People’s Hospital of Jincheng City from January 2010 to October 2018 were retrospectively analyzed. Small bone window posterior fossa decompression, modified duroplasty, resection of the cerebellar tonsillar herniation and other methods were selected to relieve nerve compression and restore normal cerebrospinal fluid circulation. The average following-up time was 55.5 months. According to the results of the last follow-up, the efficacy which was evaluated according to the Tator criteria, was divided into three grades: excellent, good, and poor. MRI was performed to assess changes in syringomyelia. Results All cases have undergone the decompression of the posterior fossa small bone window and atlantooccipital fascia lysis. Nine cases have undergone simple small bone window decompression, 21 cases have undergone modified small bone window decompression and endocranium enlarged-duraplasty. Seven cases have undergone modified small-bone-window decompression, endocranium enlarged-duraplasty and partial resection of cerebellar tonsil. According to the Tator standard, the efficacy of 19 cases is excellent (51.4%), the efficacy of 12 cases is good (32.4%), of 6 cases are poor (16.2%). The effective rate of (excellent+good) is 83.8%. Among 28 cases with syringomylia, 18 cases had syringomyelia relief, 5 cases disappeared, and 5 cases showed no significant changes. There were no cases of infection after operation, 4 cases had suffered from subcutaneous effusion and 1case had suffered from cerebrospinal fluid leakage. Conclusion Expanding the volume of the posterior fossa, relieving the nerve compression, and reconstructing the cerebrospinal fluid circulation pathway in the foramen magnum region are the basic principles for the treatment of Chiari type Ⅰ malformation. According to the different conditions of patients, selective use of posterior fossa small bone window decompression, modified duroplasty, resection of the cerebellar tonsillar herniation and other methods had reached satisfactory clinical results with fewer complications. Key words: Chiari type Ⅰ malformation; Syringomyelia; Small bone window decompression of posterior cranial fossa