Table 4.
Summary of the literature on LIV selection in AIS with thoracic curves
| Study | Curve type | Total No. of patients | Mean age (years) | Mean follow-up (years) | Conclusion |
|---|---|---|---|---|---|
| Suk et al. [50] (2003) | King type 3, 4 | 42 | 15.5 | 4.2 | When preoperative NV and EV show no more than a 2-level gap, fusion should be extended down to NV. When the gap is more than 2 levels, fusion should be extended down to NV-1. |
| Parisini et al. [40] (2009) | Lenke type 1A | 31 | 16.3 | Min. 2 | If the rotation just below the thoracic LEV is in the same direction as the thoracic curve, and SV and EV show >2-level differences, fusion should extended to L2 or L3. Otherwise, SV-2 or SV-3 should be the distal fusion level. |
| Wang el al. [56] (2011) | Lenke type 1A | 45 | - | 3.6 | Choosing the first vertebra in the cephalad direction from sacrum whose deviation from CSVL is more than 10 mm as the LIV provides the best outcomes. |
| Sarlak et al. [45] (2011) | Lenke type 1A | 36 | 15.8 | 4.3 | The distal fusion level should be extended to LEV-1 in cases of neutral L3 vertebra and to the LEV in cases of L3 vertebral tilt. |
| Takahashi et al. [52] (2011) | Lenke type 1B, 1C, 3C | 172 | 14 | 2 | If the SV is below the EV, the LIV should be chosen at least 1 level distal to the SV. If the SV and the EV are the same, the LIV is recommended to be 1 level below the SV/EV. |
| Matsumoto et al. [35] (2013) | Lenke type 1A | 112 | 16.1 | 3.6 | Fusion should be extended at least to the LTV to avoid postoperative AO. |
| Hyun et al. [17] (2015) | Lenke type 1, 2, 3, 4 | 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. |
| Fischer et al. [11] (2018) | Lenke type 1, 2 | 544 | 14.7 | 4.1 | The LIV should be the LTV or within 2 levels proximal to the NV. |
| Shen et al. [46] (2018) | Lenke type 1A | 55 | 14.2 | Min. 2 | Choosing either the SV and LSTV as the LIV can yield satisfactory correction results. |
| Qin et al. [42] (2020) | Lenke type 2A | 101 | 14.9 | Min. 2 | The fusion level should be extended to the LSTV in 2A-R (L4 tilt to right) curves and to 1 level distal from the LSTV in 2A-L (L4 tilt to left) curves. |
LIV : lower instrumented vertebra, AIS : adolescent idiopathic scoliosis, NV : neutral vertebra, EV : end vertebra, Min. : minimum, LEV : lower end vertebra, SV : stable vertebra, CSVL : center sacral vertical line, LTV : last touched vertebra, AO : adding-on phenomenon, DJK : distal junctional kyphosis, PSF : posterior spinal fusion, LSTV : last substantially touched vertebra