The Effect of Early Thoracic Fusion on Pulmonary Function in Non-Neuromuscular Scoliosis

Summary: Eighteen patients who had thoracic spine fusions before age 8yrs with minimum 5yr follow-up underwent pulmonary function testing. Age at surgery averaged 2.9yrs and at follow-up 14.6yrs. Significant restrictive disease was present in 47.1% of patients. One patient was oxygen dependent. The FVC averaged 58.8% (22-99%), and FEV1 55.1% (20-91%). PFT's were statistically related to the percent thoracic levels fused, the presence of rib deformity, and the proximal extent of the fusion.

Purpose: To determine the effect of early thoracic fusion on pulmonary function at intermediate follow-up.

Methods: Patients who had thoracic spine fusions before age 8yrs with minimum 5yr follow-up underwent pulmonary function testing. Patients with neuromuscular disease, skeletal dysplasias, or preexisting pulmonary disease were excluded, while those with rib malformations were included. PFT's from patients who had previous testing at >5yr follow-up were included.

Results: No patient had died. Eighteen patients reported for PFT's (14 congenital scoliosis, 1 congenital kyphosis, 1 infantile scoliosis, and 2 neurofibromatosis). Twelve had one spinal surgery, while six had further procedures. Age at surgery averaged 2.9 yrs (4 months-7.4 yrs), and age at follow-up 14.6 yrs (7.3-22.8 yrs). 11/18 had >10 yr follow-up. The % thoracic spine fused averaged 55.5% (33-92%). One 11 yo patient was unable to test due to oxygen dependency following fusion of 92% of the thoracic spine at 1.9 yrs. The average forced vital capacity (FVC) for the remaining 17 patients was 58.8% (22-99%) of age-matched normal values, and the average FEV1 55.1% (20-91%) . Age at fusion and PFT's were not significantly related, as 4/8 children fused age<50 %, but only 1/9 fusions beginning distal to T2 had PFT's < 50%.

Conclusion: Significant restrictive disease, defined as 4 segments, especially with rib anomalies, are at highest risk. Alternative procedures to treat early deformity are merited.