De Varona-Cocero Abel, Robertson Djani, Ani Fares, Myers Camryn, Maglaras Constance, Raman Tina, Protopsaltis Themistocles, Rodriguez-Olaverri Juan C
Department of Orthopaedics, NYU Langone Orthopedic Hospital, New York, NY, USA.
Department of Orthopaedic Surgery, Spine Research Center, NYU Langone Health, 306 E.15th St, Ground Floor, New York, NY, 10003, USA.
Spine Deform. 2025 Jul 14. doi: 10.1007/s43390-025-01142-8.
Vertebral body tethering (VBT) offers a fusion-less alternative for adolescent idiopathic scoliosis (AIS) patients, with tether breakage being a common concern, particularly in single-row VBT. Limited data exist on double-row VBT's impact on tether breakage. This study evaluates a two-row vertebral body tethering (2RVBT) technique, comparing cases with and without broken tethers in patients with over 2 year follow-up.
A single-center, retrospective review (2019-2022) included AIS patients who underwent mini-open thoracoscopic-assisted 2RVBT. Inclusion criteria were idiopathic scoliosis < 65° flexible curves, residual post-operative curves < 30°, and ≥ 2 year follow-up. Patients were divided into broken-tether (BT) and non-broken-tether (NBT) groups. Radiographic measures included thoracic (T) and thoracolumbar (TL) Cobb angles, coronal balance, L5 tilt, and sagittal parameters. Tether breakage was defined by > 5° change in screw angulation, with or without associated loss of correction.
Among 109 patients (NBT = 94, BT = 15), the overall tether breakage rate was 13.7%. The BT group had significantly larger pre-operative TL Cobb angles (53.4 ± 14.0° vs 43.7 ± 13.8°, p = 0.02), greater TL correction (- 36.2 ± 9.1° vs -2 3.7 ± 15.9°, p = 0.002), and higher post-operative coronal imbalance (21.2 ± 14.6 mm vs 11.9 ± 9.4 mm, p = 0.049). They also had significantly lower skeletal maturity (mean Risser stage 2.0 ± 1.1 vs 3.2 ± 1.3, p = 0.019; Sanders 4.0 ± 1.5 vs 5.4 ± 2.0, p = 0.019). Most broken tethers did not require revision, but some cases underwent re-tethering or fusion.
Double tether constructs may reduce the rate of tether breakage following VBT. The main risk factors for tether breakage following double tether VBT are residual post-operative coronal imbalance, larger corrections in the lumbar spine, large rigid thoracic curves, and skeletal immaturity. Furthermore, most broken tethers did not require revision, which may indicate that curves maintained appropriate correction post-breakage due to the functional lifespan of double tether constructs. Although these are preliminary findings that must be supported with further multicenter studies that include single-tether constructs, these findings should be taken into consideration when indicating patients for VBT.
椎体牵张术（VBT）为青少年特发性脊柱侧凸（AIS）患者提供了一种无需融合的替代方法，其中牵张带断裂是一个普遍关注的问题，尤其是在单排VBT中。关于双排VBT对牵张带断裂影响的数据有限。本研究评估了一种双排椎体牵张术（2RVBT）技术，比较了随访超过2年的患者中牵张带断裂和未断裂的病例。
一项单中心回顾性研究（2019 - 2022年）纳入了接受微型胸腔镜辅助2RVBT的AIS患者。纳入标准为特发性脊柱侧凸、柔韧性曲线<65°、术后残留曲线<30°以及随访≥2年。患者分为牵张带断裂（BT）组和未断裂（NBT）组。影像学测量包括胸段（T）和胸腰段（TL）Cobb角、冠状面平衡、L5倾斜度和矢状面参数。牵张带断裂定义为螺钉角度变化>5°，无论是否伴有矫正丢失。
在109例患者中（NBT = 94例，BT = 15例），总体牵张带断裂率为13.7%。BT组术前TL Cobb角显著更大（53.4±14.0° vs 43.7±13.8°，p = 0.02），TL矫正程度更大（-36.2±9.1° vs -23.7±15.9°，p = 0.002），术后冠状面失衡更高（21.2±14.6 mm vs 11.9±9.4 mm，p = 0.049）。他们的骨骼成熟度也显著更低（平均Risser分期2.0±1.1 vs 3.2±1.3，p = 0.019；Sanders分期4.0±1.5 vs 5.4±2.0，p = 0.019）。大多数断裂的牵张带不需要翻修，但有些病例进行了重新牵张或融合手术。
双排牵张带结构可能会降低VBT后牵张带断裂的发生率。双排VBT后牵张带断裂的主要危险因素是术后残留冠状面失衡、腰椎较大的矫正量、僵硬的大胸段曲线和骨骼未成熟。此外，大多数断裂的牵张带不需要翻修，这可能表明由于双排牵张带结构的功能寿命，曲线在断裂后仍保持适当的矫正。尽管这些是初步发现，必须通过包括单排牵张带结构的进一步多中心研究来支持，但在为患者选择VBT时应考虑这些发现。
