RESUMO
INTRODUCTION: The relationship between spinal structure and respiratory function has been coined as thoracic insufficiency syndrome and is defined as the inability of the thorax to support normal respiratory function or lung growth. Little is known about what supports this relationship in untreated nonambulatory myelomeningocele patients. METHODS: A prospective cross-sectional study of nonambulatory myelodysplasia patients was performed. Anatomic, radiographic, and functional parameters were evaluated to validate the respiratory-spinal structure relationship. Thirty-one patients diagnosed with nonambulatory myelomeningocele fulfilled the inclusion criteria. RESULTS: The imaging study confirmed the spinal deformity. Lung functions measured in this patient population describe reduced lung volumes by CT lung volume reconstruction, reduced vital capacity by spirometry, and reduced total lung capacity by the nitrogen washout method. Together, these findings suggest moderate restrictive respiratory disease. The blood count study did not show evidence of anemia or other blood disturbances. Echocardiogram analysis did not show pulmonary hypertension in any patient. CONCLUSION: The data validate the relationship between spinal structure and lung function. However, there is no simple structural feature that could help to diagnose thoracic insufficiency syndrome. Thus, the diagnosis continues to be based on a combination of clinical findings and radiological and respiratory function evaluations. LEVEL OF EVIDENCE: Level III.