Health and Function of Patients With Untreated Idiopathic ScoliosisHealth and Function of Patients With Untreated Idiopathic Scoliosis

To the Editor: Dr Weinstein and colleagues¹ found a wide range of long-term outcomes among a small, geographically localized cohort of adults with a childhood history of late-onset idiopathic scoliosis (LIS). I disagree, however, with their conclusion that there is "little physical impairment other than back pain and cosmetic concern." In addition to 4 deaths attributed to LIS, these individuals reported twice the incidence of chronic pain compared with control subjects, who were selected from very high-disability environments including hospital clinics.

Furthermore, the authors did not explore pulmonary disability. They did report, however, that a history of limited chest excursion was associated with reduced vital capacity, which in turn was correlated with recurrent pulmonary infections. They further reported that vital capacity remained reduced at the 30-year follow-up and that it was restricted to 2 cm or less in more than half of the cohort at the 50-year follow-up, suggesting substantial progressive loss of respiratory function.

Similarly, the authors claim that "Branthwaite found dyspnea solely due to the curvature to be extremely rare in patients with LIS." In fact, that study² found that among 40 adults with idiopathic scoliosis, 16 complained of dyspnea and nearly half of these were classified as LIS. Dyspnea is unreliable as an indicator of pulmonary compromise, however, because such patients often fail to recognize their own symptoms even when respiratory function is severely compromised.³ Branthwaite concluded that all patients with vital capacity below 50% "should be watched with particular care, so that disproportionate deterioration of lung function with age can be detected and treated early."²

Two millennia after Hippocrates observed that respiratory failure can occur in thoracic scoliosis but that some patients nevertheless achieve a normal lifespan, it remains impossible to predict the later outcomes of LIS. Under the circumstances, it is unfortunate that the authors did not discuss whether any of these patients were treated with an exercise program. An 8-day supervised exercise program can significantly reduce curvature rigidity,⁴ the defining characteristic of a structural spinal deformity and an important predictor of progression and pain.^{5 - 6} Any relationship—positive, negative, or neutral—that might exist between such treatments and the widely divergent outcomes of these patients would be of interest.