Abstract
Aiming to evaluate the efficacy and safety of instrumentation using only segmental pedicle screw fixation, we undertook a prospective study of 17 patients with idiopathic scoliosis who underwent corrective surgery in 1998 and 1999.
A total of 170 pedicle screws was inserted, 119 in the thoracic spine and 51 in the lumbar, extending from T2 to L5. The Cobb angle was measured on an erect anteroposterior radiograph postoperatively and at 6 and 12-month follow-up. Pedicle screw placement was assessed on the radiographs, and where there was concern about screw position, CT scan was performed.
Of the 170 pedicle screws, three were malpositioned lateral to the pedicle and one medial to the pedicle. One pedicle fractured during screw insertion, and three screws partially pulled out on the convex side of the curve at T3 to T5. At six months the mean Cobb angle correction was 53.6%. There were no neurological complications. Two cases required subsequent trimming of rods.
We believe fixation using only segmental pedicle screws is a safe method of correcting idiopathic scholastic deformities, but retain some reservations about the pull-out strength of the uppermost screws in the thoracic spine.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at The Department of Orthopaedic Surgery, Medical School, University of Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193 South Africa
