Mauler Flavien, Boudabbous Sana, Beaulieu Jean-Yves
Department of Plastic Surgery and Hand Surgery, Cantonal Hospital Aarau, Aarau, Switzerland.
The Hand Clinic - Geneva, Geneva, Switzerland.
J Wrist Surg. 2022 Jun 25;12(2):170-176. doi: 10.1055/s-0042-1750874. eCollection 2023 Apr.
This study describes the anatomy and analyzes the variations of the midsectional morphology of the sigmoid notch. The wrists of 50 patients with suspected scaphoid fracture were evaluated by magnetic resonance imaging (MRI). Sigmoid notch length, volar and dorsal rim heights, insertion length of the volar radioulnar ligament, and Tolat morphology classification were measured on T1-weighted axial plane MRI. Ulnar variance and distal radioulnar joint (DRUJ) inclination were assessed on anteroposterior radiographs. The most common sigmoid notch shapes were types C (C-shaped, 60%) and B (ski-slope, 30%), followed by types D (S-shaped, 6%) and A (flat, 4%). Types A and B had a flat dorsal rim (mean 0.77 ± 1.09 mm, range 0.0-1.54 mm, and mean 0.22 ± 0.3 mm, range 0.0-0.76 mm, respectively). Types C and D had more prominent dorsal rims (means 1.47 ± 0.59 mm, range 0.66-2.57 mm, and mean 1.6 ± 0.97 mm, range 0.8-2.68 mm, respectively). The average volar lip length was 1.60 ± 1.11 mm (range, 0.0-4.10). The dorsovolar length of the radius was 18.4 ± 2.01 mm; the length of the sigmoid notch was 14.3 ± 1.73 mm. The type of sigmoid notch according to Tolat was significantly associated with volar lip length ( = 0.005). The type of sigmoid notch was not associated with ulnar variance or DRUJ inclination. The length of the sigmoid notch was significantly associated with the type of sigmoid notch ( = 0.005). The analysis demonstrated a negative association between the sigmoid notch length and the volar insertion of the radioulnar ligament ( = 0.019). The transversal morphology of the sigmoid notch was either flat with the least congruence (similar to type A of Tolat), with volar congruence only (similar to type B), or with volar and dorsal congruence (similar to types C and D). A shorter sigmoid notch may be compensated by a broader insertion of the volar radioulnar ligament. The measurements and correlations demonstrated in this study can be a guide when considering reconstructive procedures or dealing with the instability of the DRUJ.
本研究描述了乙状切迹的解剖结构，并分析了其中段形态的变异情况。对50例疑似舟状骨骨折患者的腕部进行了磁共振成像（MRI）评估。在T1加权轴位MRI上测量乙状切迹长度、掌侧和背侧边缘高度、掌侧桡尺韧带的附着长度以及Tolat形态分类。在前后位X线片上评估尺骨变异和远侧桡尺关节（DRUJ）倾斜度。
最常见的乙状切迹形状为C型（C形，60%）和B型（滑雪坡形，30%），其次是D型（S形，6%）和A型（扁平形，4%）。A型和B型的背侧边缘平坦（平均0.77±1.09mm，范围0.0 - 1.54mm，以及平均0.22±0.3mm，范围0.0 - 0.76mm）。C型和D型的背侧边缘更突出（分别平均为1.47±0.59mm，范围0.66 - 2.57mm，以及平均1.6±0.97mm，范围0.8 - 2.68mm）。掌侧唇缘平均长度为1.60±1.11mm（范围，0.0 - 4.10）。桡骨的掌背长度为18.4±2.01mm；乙状切迹长度为14.3±1.73mm。根据Tolat分类的乙状切迹类型与掌侧唇缘长度显著相关（P = 0.005）。乙状切迹类型与尺骨变异或DRUJ倾斜度无关。乙状切迹长度与乙状切迹类型显著相关（P = 0.005）。分析表明乙状切迹长度与桡尺韧带的掌侧附着之间存在负相关（P = 0.019）。
乙状切迹的横向形态要么是最不匹配的扁平状（类似于Tolat的A型），要么仅掌侧匹配（类似于B型），要么掌侧和背侧都匹配（类似于C型和D型）。较短的乙状切迹可能通过掌侧桡尺韧带更宽的附着来补偿。
本研究中展示的测量结果和相关性可为考虑重建手术或处理DRUJ不稳定时提供指导。
