2.1 Introduction and Background

Spinal deformities are commonly associated with neuromuscular disorders. When using the standard definition of scoliosis (a curve greater than 10 degrees in the coronal plane using the Cobb method), the prevalence of scoliotic deformities is much higher than in the general population, ranging from 15 to 80% in some series. Comparatively, adolescent idiopathic scoliosis prevalence is only 2 to 3% in the general population. This difference is thought to be related to the muscular imbalance found in neuromuscular disorders and is further supported by the fact that more severely affected individuals have not only a higher prevalence, but also more severe scoliotic deformities. The wide range of reported incidence is probably due to the variations in the populations used in the different studies. Patient impairment, neurological dysfunction, and the nature of the neurological condition affecting the patient will significantly affect the prevalence of scoliosis. In a review of children attending an outpatient clinic, Balmer and MacEwen ¹ reported a prevalence of 21% of patients with a scoliosis greater than 10 degrees. In contrast, studies reporting on the prevalence of scoliosis in institutionalized patients with cerebral palsy (CP; thus probably more involved) have reported much higher prevalence for spinal deformities. Thometz and Simon ² reported that 61% of institutionalized patients had a scoliosis of more than 10 degrees and Saito et al ³ reported a similar prevalence of 68%. Prevalence of scoliosis also seems to be associated with neurological involvement with more severe involvement presenting a higher prevalence of scoliosis. Koop et al reported that patients with quadriplegia had a prevalence of scoliosis greater than 40 degrees in 30% of the patients, while those with diplegia had a prevalence of 10 and 2% for those with hemiplegia. ⁴

2.2 Managing Patient and Family Expectations

Patients with neuromuscular conditions have a wide range of presentations from minimal involvement in certain forms of hemiplegia to full-body involvement in severe quadriplegic CP. This wide array of clinical presentations underscores the personalized nature of the treatment to be offered to patients and families. It is essential to openly communicate with the caregiver and, when possible with the patient, to establish clear expectations and limitations of different treatment options. The benefits of nonoperative treatment versus surgical treatment must be discussed and the risk of long-term progression must be clearly explained. The goals of nonoperative treatment should also be clearly stated and realistic expectations should be set.

2.3 Bracing

Although bracing has been shown to be effective for adolescent idiopathic scoliosis, the same does not apply to neuromuscular spinal deformities. Nonetheless, many clinicians use bracing as a means to improve sitting balance and to limit progression in younger patients. Pulmonary function does not seem to be negatively affected by bracing and it may even decrease the work of breathing by improved positioning. ⁵ In a review of 90 patients, Olafsson et al found that curve progression was prevented in only 23 patients with neuromuscular disorders treated with bracing. ⁶ The main cause for progression in 41 of the 60 patients was brace discontinuation, whereas 19 patients progressed despite adequate brace wear. The authors concluded that success of bracing was more likely to occur in ambulatory patients with muscle hypotonia and short lumbar/thoracolumbar curves less than 40 degrees and nonambulating patients with spastic short lumbar curves. Rate of progression was found to be influenced only by age and initial correction in the orthosis in a study by Terjesen et al. ⁷ In another study concentrating on the results of bracing in patients with CP, Renshaw et al reported success (progression of <5 degrees) in only 22% of their 46 patients. Curve magnitude was 47 degrees at the time of bracing, and the degree of correction in the brace was small (13 degrees). ⁸

Bracing in the setting of spinal cord injury (SCI) has been shown to delay surgery if initiated early. Mehta et al ⁹ found that if bracing was initiated when the curve was less than 10 degrees, not only did the proportion of patients requiring surgery decrease, but also the surgery was often delayed by 8.5 years compared to 4.2 years for nonbraced patients. Similar trends were observed in patients with curves less than 20 degrees.

2.4 Wheelchair Modifications

More severely involved children are often confined to their wheelchair. As these patients are often difficult to brace effectively, molded wheelchair inserts became more widely used in an attempt to improve sitting balance (Fig. 2‑1). These molded inserts can be used in combination with or without a brace. Although it is unclear whether these inserts have any impact on curve progression or preventing surgery, they are particularly useful in everyday activities as they help maintain a stable sitting balance. These inserts can also help during clinical and radiological evaluation with the patient sitting in the chair to confirm improved position and decreased curve magnitude. It remains unclear, however, whether these molded inserts have any role in preventing or slowing curve progression.