Increased Kyphosis and Pain Following Implant Removal for Idiopathic Scoliosis

Methods: 39 of 54 (72%) patients whose implants had been completely removed at least two years previously completed a recent SRS-22 questionnaire and standing AP and lateral radiographs.

Results: The average time from implant removal was 10 years (Range: 3 to 18)
3 patients had between 11° to 20° of coronal plane progression of a fused thoracic curve.
1 patient had 14° of progression of a proximal junctional kyphosis.
17 patients had between 11° to 20° of progression of their thoracic kyphosis and 5 patients had > 20° of progression of thoracic kyphosis. Patients with a larger Pre-Op T5 to T-12 kyphosis were statistically more likely to progress after implant removal.(Logistic regression analysis, p=0.013)

Total SRS-22 scores averaged 75.1 for patients with <20 ° of progression thoracic kyphosis and 68.2 for patients who progressed> 20° (p= 0.034). The average score in the Pain Domain was 18.3 for patients with <20 ° of progression thoracic kyphosis and 15.0 for patients who progressed> 20° (p= 0.025) (See Table)

Conclusions: Implant removal after posterior spinal fusion for idiopathic scoliosis may not be a benign procedure. Patients should be appropriately counseled and monitored.

Group I = Patients with <10 ° sagittal progression
Group II = patients with 11° to 20° of progression in either T2 to T12 or T5 to T12
Group III = Patients with > 20° progression in either T2 to T12 or T5 to T12