The "Gulou Rule" for the selection of lowest instrumented vertebra in adolescent idiopathic scoliosis with Lenke 1A curves
10.3760/cma.j.cn121113-20240109-00024
- VernacularTitle:Lenke 1A型青少年特发性脊柱侧凸矫形术中远端融合椎选择的"鼓楼规则"
- Author:
Xiaodong QIN
1
;
Xipu CHEN
;
Yi CHEN
;
Zhong HE
;
Zhen LIU
;
Yong QIU
;
Zezhang ZHU
Author Information
1. 南京大学医学院附属鼓楼医院骨科脊柱外科，南京 210008
- Keywords:
Adolescent;
Scoliosis;
Spinal fusion;
lowest instrumented vertebra;
last substantially touching vertebra
- From:
Chinese Journal of Orthopaedics
2024;44(8):499-508
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To develop a set of lowest instrumented vertebra (LIV) selection criteria for adolescent idiopathic scoliosis (AIS) with Lenke 1A curves named as "Gulou Rule", and compared with the traditional "last substantially touching vertebra (LSTV) Rule".Methods:Based on our previous retrospective studies about LIV selection, as well as our clinical experience, the key parameters associated with LIV selection were found out and quantified to form the "Gulou Rule". A prospective consecutive collection of 189 Lenke 1A cases (male 29 cases, female 160 cases) who underwent posterior spinal fusion surgery in our clinic from January 2021 to January 2022 were recruited, with an average age of 14.9±2.8 (range 10-18) years old. They were divided into 2 groups according to the enrollment number (odd or even number). Patients with odd numbers were guided by the "LSTV Rule",while those with even numbers followed the "Gulou Rule" for the selection of LIV. The duration of follow-up was at least two years. Radiographical parameters were measured preoperatively, immediately postoperatively, and at the final follow-up, including numbers of fused segments, Cobb angle of proximal thoracic curve, main thoracic curve and lumbar curve, correction rate, coronal and sagittal balance parameters. The incidence of distal adding-on at the last follow-up was recorded.Results:The "Gulou Rule" was defined as follows: when Risser ≥3, main curve length ≤8 segments, one level proximal to LSTV (LSTV-1) rotation ≤ I degree, LSTV-1 deviation from the CSVL <20 mm, preoperative coronal balance <10 mm, and the intervertebral disc between LSTV-1 and LSTV opens bidirectionally on bending films, the LIV can be selected as LSTV-1; if these conditions are not met, LIV should be selected as LSTV. At last, 120 patients (male 21 cases, female 99 cases) were enrolled in the study with at least a 2-year follow-up, with an average age of 15.1±2.4 (range 10-18) years old. Each group had 60 patients, and the average duration of follow-up was 31.0±5.4 months for the "LSTV Rule" group and 30.8±5.1 months for the "Gulou Rule" group. The LIV in the "Gulou Rule" group was on average at the T 12 and L 1 level, where as in the "LSTV Rule" group, it was at the L 1 and L 2 level ( P=0.004). The "LSTV Rule" group had an average fused segments of 10.5±1.7, while the "Gulou Rule" group was significantly lower with 9.7±1.5 segments ( t=2.760, P=0.003). At the last follow-up, the main curve correction rates were 74.8%±10.5% and 73.2%±12.3%, respectively, with no significant difference ( t=0.779, P=0.219). The incidence of distal adding-on phenomenon was 15% in the "LSTV Rule" group and 17% in the "Gulou Rule" group, with no significant difference between the two groups (χ 2=0.063, P=0.803). Conclusion:For Lenke 1A AIS patients, both the "Gulou Rule" and the "LSTV Rule" for guiding LIV selection can achieve satisfactory correction outcomes. Choosing LIV based on the "Gulou Rule" allows for the preservation of distal fusion segments and demonstrates better clinical applicability.
