STUDY DESIGN:
Retrospective longitudinal study.

OBJECTIVE:
The main goal of this study was to measure the disability after AIS correction, according to the LIV.

SUMMARY OF BACKGROUND DATA:
Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine that may require surgical correction. If the upper and lower instrumented levels (UIV and LIV) of these fusions are defined by the characteristics of the curve, the long-term consequences of the LIV choices are still partially unknown.

METHODS:
This retrospective longitudinal study collected demographic, radiologic (Lenke classification, Cobb's angle) and surgical data (approach, LIV, UIV) on 116 patients operated for AIS fusion on a specialized pediatric spine center were collected. All participants answered SRS30, SF12, lumbar and leg pain Visual Analogue Scales (VAS) at last follow-up. Statistical analysis between LIV (T12L1, L2, L3 or L4L5) and clinical data at last follow-up was realized.

RESULTS:
The mean follow-up was 87 months. The mean increase of back pain VAS per UIV level was 9 mm. No statistically significant difference between the different LIV were found, for SRS30 or SF12 MCS (mental component scale). There was a statistically significant difference between L3 UIV and L4L5 UIV for SF-12 PCS (physical component scale); (p  =  0,03).

CONCLUSION:
The long-term consequences of LIV choice mostly affect levels distal to L3. If the LIV is mostly defined by the characteristics of the curve, one level caudally corresponds to +9 mm of back pain VAS at 7 years of follow-up. Surgeons may be aware of the long-term consequence of LIV choice and patients be informed.Level of Evidence: 4.





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