Abstract
Introduction
Only few sporting individuals with symptomatic lumbar pars injuries require surgical repair and it is often difficult to predict the outcome following surgery. The results on predictive factors of outcome after direct repair of pars defect have not been studied.
Material and Methods
52 consecutive young sporting individuals with a mean age of 19 years (range 8–35years) were treated surgically for lumbar pars defect confirmed on imaging studies (i.e., SPECT, CT and MRIscans). 50 patients completed the VAS (visual analogue scores), ODI (Oswestry Disability Index) and SF-36 (Short Form) questionnaires as a part of their assessment. Preoperative background variables were used in a multiple regression model to find the strongest predictor of post-operative outcome as measured by ODI.
Results
Buck's screw repair of the pars defect was performed in 44 patients (33M: 11 F). Unilateral in 8 patients (7M: 1F) and bilateral in 36 patients (26M: 10F). Although age at surgery showed linear co-linearity (ρ=0.32, p < 0.05), it was not significant in the model. The most consistent association with the preoperative VAS score were the pre and post operative ODI scores i.e., ρ =0.51 (p < 0.01) and ρ =0.33 (p < 0.05) respectively. In the bilateral group, with Buck's repair at a single level i.e., 33/36 (93%) patients had returned to sports at a mean time of 7.5 months (range 6–12months). Overall, 44/52 (84%) individuals had returned to their sports with post-treatment ODI score of < 10. The stepwise regression modeling suggested six independent factors (pre-operative ODI, pre-operative SF36pcs, Buck's repair, multiple operations, professionalism and pars defect at L3), as the determinants of the outcome (i.e., post-operative ODI.) in 80.9% patients (R2=0.809).
Conclusion
The outcome after direct repair of pars defect below 25 years of age runs a predictable course. Professionalism in sports has a high impact on the outcome. Preoperative ODI and SF-36 pcs scores are significant predictors of good functional outcome. The regression equation can predict the outcome in 80.9% sporting individuals undergoing Buck's repair.