SA Orthopaedic Journal
On-line version ISSN 2309-8309
STUDY DESIGN: Retrospective study of 31 patients treated for adolescent idiopathic scoliosis utilising posterior double rod constructs with a limited number of strategically placed screws. OBJECTIVE: Review of the radiological and clinical outcomes of strategic screw placement in posterior double rod constructs with respect to implant density. SUMMARY OF BACKGROUND DATA: The trend in scoliosis surgery dictates the use of pedicle screw constructs with anchors at every level. Favourable correction and clinical outcomes have been reported using this technique. The cost burden of such an implant construct is high; with the additional risk of pedicle breach and neurological compromise multiplied by the number of screws. The sustainability of this practice is questionable. METHODS: Thirty-one patients, treated surgically for adolescent idiopathic scoliosis, with a minimum two-year follow-up, were included. Posterior double-rod constructs were used in all cases. Cobb angles were measured pre-operatively, post-operatively and at two-year follow-up. Patient satisfaction and clinical outcome were evaluated through the SRS22 questionnaire. RESULTS: Lenke classification yielded 16 type I, seven type II, four type III, two type IV and two type VI curves. The average Cobb angle pre-surgery was 68.5° (±17.6°), with a flexibility of 38%. This was corrected to an average of 24°±11.9°. The correction was maintained at two-year follow-up. In terms of thoracic sagittal profile, 25 patients measured 'normal' (10°-40°) post-operatively, compared to 17 pre-operatively. This correction was achieved with a 52.2% metal density over an average of nine instrumented segments. Average SRS22 patient satisfaction score was at 89%. CONCLUSION: Strategic screw placement, in adolescent idiopathic scoliosis surgery, yields adequate correction and curve maintenance. High levels of patient satisfaction were achieved at a dramatically reduced cost, with a diminished risk for pedicle violation.
Keywords : adolescent idiopathic scoliosis; posterior fusion; pedicle screws; metal density.