A retrospective study on outcomes following posterior fossa decompression with dural splitting surgery in patients with Chiari type I malformation

Background: Chiari type I malformation (CM I) is a congenital defect of the skull base and brain. Posterior fossa decompression alone or with duraplasty and partial resection of cerebellar tonsils is a standard approach. The effectiveness of other approaches such as the dural splitting technique is still under the study.

Objective: To study and compare the outcome following a dural splitting surgery with the duraplasty group.

Method: 184 patients that received dural splitting surgery and 39 patients that received duraplasty surgery were identified. The outcome of the individual procedure in terms of symptoms, pre- and postoperative presence of syrinx, operation time, hospital admission period, and Chicago Chiari Outcome Scale (CCOS) were analyzed and compared.

Results: The observed values in terms of symptomatic relief between the two groups were similar Pearson's chi-square test was 0.677 with p=0.411. Independent samples Mann-Whitney U test to analyze CCOS score showed p = 0.249 at Z = 1.152. The average postoperative period in days was less in PFDDS group 9.25 days, the average admission period in days for the group was less in PFDDS group 14.23 days with p < 0.0005. Fisher's exact test showed the Syrinx disappearance rate was better in the PFDDS group. The average duration for surgery was less on the PFDDS group.

Conclusion: Our study showed that more optimal results were obtained in terms of syrinx resolution as well as shorter operation time and postoperative stay among the PFDDS group. Both procedures are equally effective in terms of CCOS score.