INFANTILE IDIOPATHIC SCOLIOSIS: RESPIRATORY OUTCOME AFTER AGE 15 YEARS

Abstract

Objective: To assess the treatment outcome at a minimum age of 15 years in patients who had presented with idiopathic scoliosis in infancy.

Design: Patients were recalled for full pulmonary function testing (spirometry, lung volumes and gas diffusion) and surface topography. Results were correlated with history and clinical radiographs.

Subjects: The records showed 32 patients, of whom 23 could be contacted and agreed to take part in the study. Thirteen had no other abnormality, and 9 had a variety of additional problems not thought to directly precipitate their spinal deformity. There were 13 female and 9 male and age at testing ranged from 15.2 to 30.2 years.

Outcome measures: Spirometry (forced vital capacity (FVC), forced expiratory volume in one minute (FEV₁)), lung volumes ( total lung capacity (TLC), residual volume (RV)) and gas diffusion (carbon monoxide diffusion (DLCO), and alveolar volume (VA)) were correlated with the most recent Cobb angle, surface topography and age at surgery where applicable.

Results: Those who were successfully managed without recourse to surgery (N=6) had normal cosmesis and pulmonary function (mean FEV₁ = 98.7%, mean FVC = 96.6%). When surgery had been postponed until after age 10 (N=6, mean age at surgery 12.9 years) pulmonary function showed some restriction (mean FEV₁ = 79%, mean FVC = 68.3%). Those who underwent corrective surgery before age 10 years (N=11, mean age at surgery 4.1 years) had significant recurrence of deformity and diminished respiratory function (mean FEV₁= 41%, range 14 – 72%, mean FVC = 40.8%, range 12 – 67%). There was statistically significant correlation (p< 0.01 or less) between respiratory measures on the one hand and age at surgery (where applicable), surface topography measures and latest Cobb angle.

Conclusions: It has been reported that only in early-onset scoliosis is the growth of lung tissue and the multiplication of alveoli impeded[1,2] and treatment is directed at preserving both pulmonary function and cosmesis. Early surgery is recommended on the assumption that the Cobb angle can be controlled and normal pulmonary development enabled in those whose scoliosis did not respond to conservative methods. Methods have changed since the earlier cases in this series were treated, and it is hoped that later results will be different. However, caution requires that, in monitoring these patients, cosmesis and, more importantly, respiratory function be considered before a conclusion is drawn.