INCIDENCE OF PARS DEFECTS IN ADOLESCENT IDIOPATHIC SCOLIOSIS –MRI STUDY

Abstract

Incidence of pars defect associated with idiopathic scoliosis has been reported as 6% based on roentgenographic evaluation in previous studies. (Fisk et al, 1978). We aim to present our results in an MRI based study.

Methods: 229 patients of adolescent idiopathic scoliosis (AIS) who had an MRI scan over a period of three years (2006–2008), performed either as a preoperative investigation or due to other symptoms were reviewed. All MRI scans were reviewed by two experienced musculoskeletal radiology consultants independently.

Result

Among 229 patients 18 (7.86%) patients were found to have pars defect. Mean age-group of patients were (19 years, range-11–40). Male-5 (26.3%), female- 4(73.6%). Majority of the patients with were females (72.2%). There was varying severity of curve patterns, major thoracic curve-10, major lumbar curve-4, mild thoracic curve-3 and mild lumbar curve in one. Bilateral pars defect was noted in 14 (77.7%) patients.

Discussion

Previous studies (Fisk et al, 1978; Mau H 1977) have described the incidence of pars defect as approximately 6.2%. Recent studies have emphasized use of MRI to diagnose pars defect based on signal changes in the pedicle (Jon R. Davids et al, 2004). Our study reveals the incidence of pars defect in AIS to be 7.86 % based on MRI diagnosis which does not seem to be different to previous roentgenographic studies.