[Surgical treatment of idiopathic scoliosis with multisegmental posterior instrumentation and its influence on postoperative spinal balance].

Causes of postoperative spinal imbalance in patients with idiopathic scoliosis treated with multisegmental posterior instrumentation CD or TSRH and posterior fusion are presented. Investigation included 88 patients (77 girls, 11 boys) aged 11.4-17.1 (mean 13.8). Primary curve Cobb angle ranged from 52 (to 133 mean 75), secondary curve 16 (to 88 mean 47). Follow-up ranged from 12 to 19 months (mean 18.2 months). In 31 patients (35.2%) postoperative decompensation of the spine occurred. Six of them regained spinal balance within 12 to 19 months postoperatively. As the magnitude of correction increased in relation to preoperative correctiveness and/or preoperative rotation of the spine the imbalance of the spine was more pronounced. It was worsened also in cases where spontaneous correction within the secondary curve (not instrumented) was lesser than expected. Thoracic curve overcorrection in type II scoliosis with instrumentation inclusive of 1 or 2 vertebrae beyond neutral one resulted in decompensation to the left. To short a fusion (in relation to neutral and stable vertebrae) caused in this type as well as in type II and IV right sided decompensation. Overcorrection of lower (right sided) curve or omission of upper (left sided) curve in type V scoliosis caused shoulder girdle decompensation. In type I lumbar fusion done proximally to neutral and stable vertebrae caused left side decompensation of the spine.