Surgical growth guidance with non-fused anchoring segments in early-onset scoliosis

Abstract

Purpose: Surgical treatment of early-onset scoliosis (EOS) requires a balance between maintained curve correction and the capacity for spinal and thoracic growth. Spinal fusion creates irreversible conditions that prevent the implementation of further treatment methods. Our hypothesis was that non-fused anchors in growth guidance show a comparable outcome as the technique described in the literature, which involves spondylodesis of the anchoring segments.

Methods: This retrospective study analysed 148 surgeries in 22 EOS patients (11 female, 11 male) over a 15-year period. Patients underwent surgery with non-fused anchors and growth guidance techniques. Scoliosis, kyphosis, growth and anchoring segments were measured. For the latter, a new measuring technique was developed. Complications were recorded and classified.

Results: The mean Cobb angle reduced from 73.5 ± 24.4° to 28.4 ± 16.2° (60.2 ± 22.9%, p < 0.001) at the last follow-up. Spinal growth T1-S1 and T1-T12 were 41.1 ± 23.3 mm and 24.9 ± 16.6 mm (p < 0.001), respectively. Growth at the cranial and caudal anchoring segment was 1.5 mm/segment/year and 1.9 mm/segment/year, respectively. A total of 63 complications were documented in 20 patients, with 40 requiring unplanned revision surgery. Definitive spondylodesis was performed in three patients.

Conclusion: Patients demonstrated a significant spinal growth including the anchoring segments. A comparable correction in Cobb angle and the type of complications was noted, although the rate of device-related complications was higher. No permanent impairment was reported. The rate of device-related complications is acceptable and outweighed by the significant degree of growth preservation and more flexible and individualised treatment strategy for patients with EOS. These slides can be retrieved under Electronic Supplementary Material.

Keywords: Early-onset scoliosis; Early-onset spinal deformities; Growing rods; Growth guidance; Non-fusion anchoring.