Continued deterioration in pulmonary function at average 23-year follow-up from early thoracic fusion in non-neuromuscular scoliosis

Purpose: Historically, early-onset scoliosis was treated with early fusion to prevent further deformity at the expense of thoracic growth. This has proven to have a detrimental effect on pulmonary function. The purpose of this study is to evaluate patients’ pulmonary and functional status at long-term follow-up after undergoing thoracic fusion at a young age. Methods: All patients at a single institution who had undergone thoracic spinal fusion prior to age nine with minimum 13-year follow-up were eligible. Patients underwent pulmonary function testing, radiographic analysis, and functional testing. Results were compared to the patients’ previous pulmonary function data at average of 11 years post-surgery. Results: Fifteen out of twenty-eight eligible patients returned for testing. The average age at the time of surgery was 3.3 years (range 0.9–8.4 years) with follow-up of 23.6 years (range 13.2–33.2 years). There was a statistically significant interval decline in predicted forced vital capacity (42.8% versus 54.7% of normal predicted values, p = 0.0001) and predicted forced expiratory volume in one second (42.2% versus 55.2% of normal predicted values, p = 0.0001) when compared to previous follow-up. There was a strong positive correlation between thoracic height and forced vital capacity (r = 0.925, p = 0.002). Conclusions: Pulmonary function in patients who had undergone thoracic spinal fusion for scoliosis prior to the age of six continues to decline into adulthood at a rate that is faster than that of their peers. The majority of these patients have clinically important restrictive lung disease, which can be fatal. Alternative treatment strategies should be considered. Level of evidence: III.