Background: Despite progress in the understanding of the causes and pathophysiology of Chiari-I malformation (CM-I), definitive surgical treatment remains unresolved. Various techniques have been propounded over the years, but there is no general consensus on the most appropriate surgical management for this condition.

Aim:  To compare patients related surgical results of Foramen Magnum Decompression with and without lax Duraplasty in Chiari Malformation Type-I with syringomyelia.

Settings and Design: This is a patient related prospective surgical outcome study conducted durong the period of four years from 2013 to 2017 in Stanley medical college, chennai.

Materials and Methods: Thirty five cases of CM-I with Syrinx were included. There were 12 patients (34.3%) in the non-duraplasty Group-A and 23 pa­tients (66.7%) in the Lax duraplasty Group-B. The rate of patient clinical improvement in the form of preoperative and postoperative VAS pain score and nurick’s score, reduction of postoperative Syrinx size, amount of tonsillar herniation, preop­erative symptom duration and postoperative improvement , complications and reoperation rates were analysed for a minimum follow up period of one year.

Results: The rate of clinical improvement was significantly higher with Lax duraplasty Group-B (94.6%) than Group-A (15.4% with significant p <0.05. The rate of postoperative syrinx regression was significantly higher in the duraplasty Group-B (94.6%) than in the non-duraplasty Group-A (15.4%). No case in the duraplasty Group-B needed a reoperation compared with five cases in the non-duraplasty Group-A.

Conclusion: FMD with Lax  Duraplasty(Group-B) is superior to stand alone FMD(Group-A)in CM-I associated with Syrinx with the expense of a slightly higher procedure related complication rate.

Keywords: Chiari Malformstion, Lax duroplasty, Syrinx, Tonsillar Herniation.

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Dr P. Pallavan. M.Ch

Neurosurgery Post Graduate

Government Stanley Medical College, Chennai, Tamilnadu, India