Neuromuscular scoliosis in children with spinal cord injury.

Neuromuscular scoliosis is a complex secondary condition of pediatric spinal cord injury (SCI)1–4 that develops in nearly all children injured prior to skeletal maturity.3,5,6 The secondary complications of neuromuscular scoliosis often include pelvic obliquity, skin breakdown, pulmonary compromise, and functional decline.2 Because of the potentially devastating consequences of neuromuscular scoliosis on body functions and the high rate of complications associated with spine surgery for neuromuscular scoliosis,7 treatment to prevent or slow the progression of neuromuscular scoliosis is a primary focus of the longitudinal care of children with SCI. Although the evidence on the effectiveness of bracing for neuromuscular scoliosis is low,4,8 the assumed benefits of a thoracolumbar sacral orthosis (TLSO) likely outweigh the risks. Thus, a brace is usually prescribed.8–10 One factor thought to influence the effectiveness of bracing on neuromuscular scoliosis is curve severity; curves less than 40° have been shown to respond to brace treatment whereas curves greater than 40° have shown minimal to no response to the brace.8 Despite any potential benefits of the brace, there are no dosing studies to inform recommendations about wearing time. As a result, recommendations for wearing time range from “while up in chair” to “23 hours a day” with many variations. Children report loss of function while wearing the TLSO, particularly function associated with wheelchair pushing, transfers in and out of the chair, and functional reach.9 For children with hyperhidrosis or those living in warm and tropical geographical locations, tolerance to the brace can be low. Also, despite brace treatment, scoliosis in children with SCI usually progresses and requires a definitive spinal fusion to prevent progression to a magnitude that becomes life threatening.3 For some children with curves under 40°, alternative treatment to the brace is available in the form of surgical intervention using “growing instrumentation systems.”11 Generally, growing systems are designed to surgically correct the scoliosis using spinal instrumentation without performing a spinal fusion; every 3 to 6 months, the spinal instrumentation is elongated to accommodate spinal growth. Growing systems require repeated surgeries under anesthesia. Scoliosis is controlled throughout middle childhood, but a definitive spinal fusion is typically performed during middle adolescence. Spinal fusions are effective in arresting progressive neuromuscular scoliosis, but they are not without complications. Although preoperative pulmonary status, curve angle, and age may be predictors of postoperative complications,12,13 the risk of pulmonary complications, pseudoarthrosis, and infections is high in all children undergoing spine surgery for treatment of neuromuscular scoliosis.7 Although rare, vision loss has also been reported as a complication of spine fusion in a child with SCI.14 Perhaps the greatest clinical challenge associated with managing neuromuscular scoliosis and making treatment recommendations for children with SCI is the uncertainty about which factors are most strongly associated with curve progression. Based on the literature, age at time of injury has been recognized as the strongest determinant of progression of neuromuscular scoliosis and ultimately surgical fusion.1,2,5,6,10 However, no study has evaluated the neurological characteristics of an adequate number of children with SCI using standardized and valid methods to determine whether they are associated with progressive neuromuscular scoliosis. Over the last 5 years, we have systematically evaluated 217 children with SCI using the techniques of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI)15,16 and have calculated Cobb angles as measures of neuromuscular scoliosis. We hypothesized that in addition to age at injury, neurological level, motor score, and injury severity as defined by the ISNCSCI would be strong predictors of neuromuscular scoliosis and that knowledge about these SCI characteristics, as they relate to scoliosis, could inform preventative management. Thus, the purpose of this study was to investigate the determinants of neuromuscular scoliosis as a function of age at injury, sex, neurological level, motor score, and injury severity as defined by the American Spinal Injury Association Impairment Scale (AIS).16