Cotrel–Dubousset instrumentation in neuromuscular scoliosis

Abstract

The study design is retrospective. The aim is to describe our experience about the treatment of patients with neuromuscular scoliosis (NMS) using Cotrel-Dubousset instrumentation. Neuromuscular scoliosis are difficult deformities to treat. A careful assessment and an understanding of the primary disease and its prognosis are essential for planning treatment which is aimed at maximizing function. These patients may have pelvic obliquity, dislocation of the hip, limited balance or ability to sit, back pain, and, in some cases, a serious decrease in pulmonary function. Spinal deformity is difficult to control with a brace, and it may progress even after skeletal maturity has been reached. Surgery is the main stay of treatment for selected patients. The goals of surgery are to correct the deformity producing a balanced spine with a level pelvis and a solid spinal fusion to prevent or delay secondary respiratory complications. The instrumented spinal fusion (ISF) with second-generation instrumentation (e.g., Luque-Galveston and unit rod constructs), are until 1990s considered the gold standard surgical technique for neuromuscular scoliosis (NMS). Still in 2008 Tsirikos et al. said that "the Unit rod instrumentation is a common standard technique and the primary instrumentation system for the treatment of pediatric patients with cerebral palsy and neuromuscular scoliosis because it is simple to use, it is considerably less expensive than most other systems, and can achieve good deformity correction with a low loss of correction, as well as a low prevalence of associated complications and a low reoperation rate." In spite of the Cotrel-Dubousset (CD) surgical technique, used since the beginning of the mid 1980s, being already considered the highest level achieved in correction of scoliosis by a posterior approach, Teli et al., in 2006, said that reports are lacking on the results of third-generation instrumentation for the treatment of NMS. Patients with neuromuscular disease and spinal deformity treated between 1984 and 2008 consecutively by the senior author (G.D.G.) with Cotrel-Dubousset instrumentation and minimum 36 months follow-up were reviewed, evaluating correction of coronal deformity, sagittal balance and pelvic obliquity, and rate of complications. 24 patients (Friedreich's ataxia, 1; cerebral palsy, 14; muscular dystrophy, 2; polio, 2; syringomyelia, 3; spinal atrophy, 2) were included. According the evidence that the study period is too long (1984-2008) and that in more than 20 years many things changed in surgical strategy and techniques, all patients were divided in two groups: only hooks (8 patients) or hybrid construct (16 patients). Mean age was 18.1 years at surgery (range 11 years 7 months-max 31 years; in 17 cases the age at surgery time was between 10 and 20 years old; in 6 cases it was between 20 and 30 and only in 1 case was over 30 years old). Mean follow-up was 142 months (range 36-279). The most frequent patterns of scoliosis were thoracic (10 cases) and thoracolumbar (9 cases). In 8 cases we had hypokyphosis, in 6 normal kyphosis and in 9 hyperkyphosis. In 8 cases we had a normal lordosis, in 11 a hypolordosis and in 4 a hyperlordosis. In 1 case we had global T4-L4 kyphosis. In 8 cases there were also a thoracolumbar kyphosis (mean value 24°, min 20°-max 35°). The mean fusion area included 13 vertebrae (range 6-19); in 17 cases the upper end vertebra was over T4 and in 11 cases the lower end vertebra was over L4 or L5. In 7 cases the lower end vertebra was S1 to correct the pelvic obliquity. In 5 cases the severity of the deformity (mean Cobb's angle 84.2°) imposed a preoperative halo traction treatment. There were 5 anteroposterior and 19 posterior-only procedures. In 10 cases, with low bone quality, the arthrodesis was performed using iliac grafting technique while in the other (14 cases) using autologous bone graft obtained in situ from vertebral arches and spinous processes (in all 7 cases with fusion extended until S1, it was augmented with calcium phosphate). The mean correction of coronal deformity and pelvic obliquity averaged, respectively, 57.2% (min 31.8%; max 84.8%) and 58.9% (mean value preoperative, 18.43°; mean value postoperative, 7.57°; mean value at last follow-up, 7.57°). The sagittal balance was always restored, reducing hypo or hyperkyphosis and hypo or hyperlordosis. Also in presence of a global kyphosis, we observed a very good restoration (preoperatory, 65°; postoperatory, 18° kyphosis and 30° lordosis, unmodified at last f.u.). The thoracolumbar kyphosis, when present (33.3% of our group) was always corrected to physiological values (mean 2°, min 0°-max 5°). The mean intraoperative blood lost were 2,100 cc (min 1,400, max 5,350). Major complications affected 8.3% of patients, and included 1 postoperative death and 1 deep infection. Minor complications affected none of patients. CD technique provides lasting correction of spinal deformity in patients with neuromuscular scoliosis, with a lower complications rate compared to reports on second-generation instrumented spinal fusion.