Prevalence of junctional kyphosis in early-onset scoliosis: can it be corrected at final fusion?

Purpose: To investigate the risk and predictive factors of junctional issues after conversion from Traditional growing rod (TGR) to definitive spinal fusion in Early-onset scoliosis (EOS).

Methods: Retrospective review of a multicenter EOS database. TGR patients who received final fusion with at least two-year follow-up were included. Proximal (PJA) and Distal junctional angles (DJA) on pre-final fusion, post-final fusion (within one year of surgery), and at latest follow-up were measured on lateral upright spinal radiographs. Differences in values among designated time points and predictive factors of junctional issues were evaluated statistically.

Results: Forty-six of 251 patients (28 females, 18 males and mean age at final fusion: 12 ± 2 [9-17] years) met the inclusion criteria. Mean follow-up between first postoperative measurement and latest follow-up was 49 ± 22 (24-112) months. No statistical differences in PJA and DJA values were available at pre-fusion, first post-fusion, or latest follow-up (p = 0.827, p = 0.076). Fifty percent of patients had extension of TGR instrumentation at fusion, either proximal or distal. No factor including sex and etiology, lumbar lordosis, thoracic kyphosis, major curve magnitude, PJA, and DJA at pre-fusion was found to be a predictive issue for extension of index TGR instrumentation, except the history of at least one implant-related complication during the period from index surgery to the definitive fusion.

Conclusion: PJA and DJA remained stable when transitioning from TGR to final posterior spinal fusion. But 50% of patients had extension of construction at fusion, either proximal or distal.