Do the benefits of hook-hybrid construct justify their use over all-pedicle screws constructs in maintaining postoperative curve correction for adolescent idiopathic scoliosis patients from an Asian population?

STUDY

DESIGN

Retrospective study.

OBJECTIVE

(1) Compare outcomes of all-pedicle screws (PS) and hook-hybrid (H) constructs in adolescent idiopathic scoliosis (AIS) patients; and (2) investigate whether BMI, height or pedicle size may modify the effect of the type of surgical construct on the extent of curve decompensation.

METHODS

AIS patients who underwent surgical fixation with H or PS constructs at a single tertiary institution were reviewed. Patients with implant density of at least 70% and 2-year follow-up were included. Demographic and perioperative data collected were age, sex, height, BMI, implant density and pedicle diameter. Cobb's angles and curve correction were compared preoperatively, postoperatively and at follow-up.

RESULTS

In total, 59 patients were included. H group had a lower pedicle size at the highest level of construct and at T4 compared to PS group. Postoperatively, H group (30.2° ± 11.7°) and PS group (32.1° ± 10.4°) had similar correction (mean diff. 2.0°, p = 0.516). At 2-year follow-up, H group (1.6° ± 3.5°) and PS group (0.1° ± 2.8°) had similar curve deterioration (mean diff. 1.5°, p = 0.079). Uni- and multivariate analyses revealed that BMI and height were not associated with curve deterioration at 2-year follow-up among the H and PS groups.

CONCLUSION

H constructs provided similar maintenance of curve correction at 2-year follow-up compared to PS constructs. BMI and Stature did not modify curve deterioration between both groups at follow-up. This study supports the use of H constructs when faced with difficult pedicle morphology associated with shorter stature as it provides comparable and satisfactory long-term maintenance of curve correction.

LEVEL OF EVIDENCE: Level III, retrospective cohort study.