Table 6.
Summary of the literature on LIV selection in AIS with thoracolumbar/lumbar curves
| Study | Curve type | Total No. of patients | Mean age (years) | Mean follow-up (years) | Conclusion |
|---|---|---|---|---|---|
| Ding et al. [8] (2014) | - | 60 | 15.4 | Min. 2 | There were no significant differences in clinical scores between the L3 and the L4 group. |
| Sun et al. [51] (2014) | Lenke 5 | 37 | 14.9 | 3.5 | There was no benefit of fusing to LEV+1 in moderate TL/L idiopathic scoliosis patients compared to fusing to LEV. If the TL/L Cobb angle is more than 60°, the distal fusion level probably needs to be LEV+1. |
| Kim et al. [24] (2014) | Lenke 5 | 66 | 15.2 | Min. 2 | Fusion to L3 showed favorable radiographic outcomes when L3 crossed the mid-sacral line with rotation of less than grade II in bending films. Otherwise, fusion has to be extended to L4. |
| Hyun et al. [17] (2015) | Lenke 5, 6 | 76 | 14.7 | 3.2 | To prevent AO or DJK following PSF to L3, the CSVL should touch L3 on upright and bending films, the L3/4 disc should be flexible, L3 should be neutral (<15°) and ≤2 cm from the CSVL, and patients should be ≥ Risser 2. |
| Lee et al. [30] (2016) | Lenke 3C, 5, 6 | 229 | 15.6 | 3.7 | Fusion to L3 may be sufficient if LEV ≥ L3 and LTV ≥ L4. |
| Chang et al. [3] (2017) | Major TL/L curves | 64 | 15.0 | Min. 2 | If the curve is flexible (L3 crosses CSVL with a rotation < grade II), LIV should be selected at L3 (LEV). |
| Ilharreborde et al. [20] (2017) | Lenke 5 | 78 | 16.0 | 4.6 | Hyperselective (when the apex was located on a vertebral body, fusion extended 1 vertebra below; while if the apex was located on a disc, fusion extended 2 vertebrae below) posterior fusions can be considered, preserving 1 or 2 mobile segments, with similar clinical and radiological outcomes. |
| Daher et al. [7] (2019) | Below L2 with lumbar modifier B, C | 25 | 15.2 | 3.2 | Stopping fusion at L3, which presents similar clinical and radiographical results in the short term, may be a good option in order to save levels in the lumbar region. |
LIV : lower instrumented vertebra, AIS : adolescent idiopathic scoliosis, Min. : minimum, LEV : lower end vertebra, TL/L : thoracolumbar/lumbar, AO : adding-on phenomenon, DJK : distal junctional kyphosis, PSF : posterior spinal fusion, CSVL : center sacral vertical line, LTV : last touched vertebra