ADOLESCENT IDIOPATHIC SCOLIOSIS - LONG-TERM EFFECT OF INSTRUMENTATIONEXTENDING TO THE LUMBAR SPINE

We evaluated eighty-three patients in whom adolescent idiopathic scoli osis had been treated with a posterior spinal arthrodesis and Harringt on instrumentation extending to the second, third, fourth, or fifth lu mbar vertebra. All eighty-three patients completed a questionnaire, an d fifty-five patients were also examined clinically and roentgenograph ically at a follow-up evaluation at an average of twelve years (range, ten to sixteen years). Twelve patients had a type-I curve; twenty-six , a type-II curve; sixteen, a type-III curve; and one, a type-IV curve , according to the classification of King et al. The preoperative Cobb angle of the primary curve averaged 60 degrees and ranged from 40 to 100 degrees. The curve was an average of 35 degrees (range, 15 to 65 d egrees) at the most recent follow-up evaluation. Functional assessment with use of information from the questionnaire revealed an average sp ine score of 81 points (range, 18 to 99 points). On the basis of the s core, thirty-five patients were considered to have had an excellent re sult; twenty, a good result; thirteen, a fair result; and fifteen, a p oor result. Sixty-three (76 per cent) of the eighty-three patients had low-back pain compared with thirty (50 per cent) of sixty individuals who served as a control group. This difference was significant (p < 0 .001; chi-square test). Eighteen patients (22 per cent) needed additio nal spinal procedures. Fourteen patients (17 per cent) did not think t hat the goals of the initial operation had been accomplished. Linear r egression analysis showed a significant relationship between a lower s pine score and an increased Cobb angle of the secondary curve (p = 0.0 2), increased kyphosis (p = 0.001), and sclerosis of facets (p = 0.04) . A low er spine score was not significantly associated with decreased lumbar lordosis or with an arthrodesis to the caudad segments of the lumbar spine. However, patients in whom the arthrodesis had extended t o the caudad segments did have a significantly increased prevalence of degenerative changes on the roentgenograms (p = 0.4).