Adding Expansile Duraplasty to Posterior Fossa Decompression May Restore Cervical Range of Motion in Grade 3 Chiari Malformation Type 1 Patients.

Abstract

Few studies have assessed the effect of Chiari malformation type 1 (CM-1) surgical decompression on cervical lordosis and range of motion (ROM). We aimed to assess the effect of expansile duraplasty on postoperative cervical mobility and spinal stability. This was a single-center retrospective review of prospectively collected data. Patients were included if they underwent surgical treatment for symptomatic CM-1 between the years 1999 and 2009. Cervical ROM and lordosis were assessed before and after surgery in all patients. Collected data also included clinical improvement, as well as surgical complications after the procedure. Patients were divided into 2 groups. The first group underwent a posterior fossa bony decompression alone, while the second group additionally received an expansile duraplasty. Patients were further subdivided into 3 subgroups on the basis of the severity of tonsillar herniation. A total of 76 patients fit our selection criteria. Fifty-five patients belonged to the duraplasty group. Twenty-one patients underwent bony decompression alone. The 2 groups were statistically demographically and clinically similar. There was no difference in clinical outcome or in ROM and cervical lordosis between the groups except for patients with severe tonsillar herniation (CM-I grade 3). These patients had a statistically significant improvement in their postoperative cervical motility without compromising their spinal stability. Adding an expansile duraplasty to craniovertebral decompression in CM-1 patients with severe tonsillar herniation may restore cervical ROM while preserving stability and alignment. This may relieve postoperative pain and improve clinical prognosis.