494 - Does Surgical Approach affect Outcomes in AIS Patients with 70° or Lar...

General Session: Pediatric Spine - Hall F

Presented by: S.Y.G. Fung

Author(s):

G. Liu(1), H. W Najjar(1), J.H. Tan(1), S.Y.G. Fung(2), L.-L. Lau(1), H.W.D. Hey(1), J. Thambiah(1), H.-K. Wong(1)

(1) National University Health System, Singapore, Singapore
(2) National University of Singapore, Singapore, Singapore

Abstract

Introduction: The surgical approach to managing AIS curves ≥70 is often based on one´s clinical experience. Few studies have compared the outcomes of surgical approach in large AIS curves based on the curve flexibility of the patients.

Methods: A prospective study of all pre-operative and post-operative AIS curves ≥ 70° in a university hospital were reviewed. Patients´ clinical and radiological outcome data were recorded and analysed using SPSS software. Curve Flexibility was defined as: "Pre-operative erect Cobb angle of major structural curve-corresponding bending angle" / "Pre-operative erect Cobb angle".

Results: 51 patients (7♂ , 44♀ ) with mean age of 14 (10-18) years and median Risser Classification of 4 (0-5) were reviewed. Patients were divided into two groups, Group A: < 30% Curve Flexibility and Group B: ≥30% Curve Flexibility (Group B). Group A consisted of 20 patients, with mean age of 14±2yrs and Cobb angle of 84° (70-140). Group B consisted of 31 patients, with mean age of 14±2yrs and Cobb angle of 81° (70-102). In Group A, 12 patients had undergone standalone Posterior surgery (4 of 12 patients had average of 3.8 Ponte osteotomies each), and 8 patients had undergone both Anterior and Posterior surgery (4 of 8 patients had average of 3.5 Ponte osteotomies each). The mean number of levels fused was 12 (8-14), with a mean implant density of 1.6 screws/level. The mean curve correction was 54° (26-82). In Group B, 25 patients had undergone standalone Posterior surgery (2 of 25 patients had average of 3.0 Ponte osteotomies each), and 6 patients had undergone both Anterior and Posterior surgery (3 of 6 patients had an average of 4.7 Ponte osteotomies each). The mean number of levels fused was 12 (11-15), with mean implant density of 1.5 screws/level. The mean curve correction was 60° (43-102). Multivariate analysis showed that in Group A patients, there is a statistically significant longer operation time (OR=7.6, 95%CI:1.6-36, p-value=0.011), hospital stay (OR=3.2, 95%CI:1.8-6.1, p-value=0.005), less Cobb angle correction (OR=0.92, 95%CI:0.85-0.94, p-value=0.05), and a trend towards more blood loss. There was no statistical difference found in the demographics between both groups. Interestingly, subgroup analysis comparing standalone Posterior surgery vs both Anterior and Posterior surgery in both Group A and Group B patients did not show a statistically significant difference in Cobb correction and post-operative outcomes scores.

Conclusion: This study suggests that Cobb angle correction were based on curve flexibility. Curves with < 30% flexibility had a 64% correction, while curves ≥30% flexibility had a 75% correction. Interestingly, there was no evidence to demonstrate that both Anterior and Posterior surgery is superior to standalone Post surgery, suggesting a need for larger cohort studies to validate the routine need for anterior release for large rigid scoliosis curves.