Department of Orthopaedic Surgery, Hand & Upper Extremity Surgery, Baylor College of Medicine, Houston, Texas, USA.
Department of Orthopaedic Surgery, Hand & Upper Extremity Surgery Center, Emory University School of Medicine, Atlanta, Georgia, USA.
Microsurgery. 2023 Sep;43(6):597-605. doi: 10.1002/micr.31036. Epub 2023 Mar 14.
Supinator to posterior interosseous nerve (SPIN) transfer allows reconstruction of finger/thumb extension and thumb abduction for low radial nerve palsy, incomplete C6 tetraplegia, and brachial plexus injury affecting C7-T1. No study has compared dorsal versus volar approach to perform SPIN transfer. This comparison is studied in the present work, assessing supinator motor branch length and ability to achieve nerve transfer from either approach.
Ten fresh frozen cadavers were randomly allocated to receive either a dorsal or volar approach to PIN and supinator radial and ulnar branches (RB = radial, UB = ulnar). Supinator head innervation patterns were documented. RB and UB lengths, forearm lengths measured from ulnar styloid to olecranon, visualization of extensor carpi radialis brevis (ECRB) motor nerve without additional dissection, and ability to perform tension-free nerve transfer were assessed.
Nine of 10 specimens had supinator branches innervating both heads. The ECRB nerve was visualized in all volar but only one dorsal approach. No significant differences in forearm length were found. Volar with elbow extended: mean RB length was 35 ± 7.8 mm and UB was 37.8 ± 9.3 mm. Dorsal with elbow extended: mean RB length was 30 ± 4.1 mm and UB was 38.8 ± 7.3 mm. Dorsal with elbow flexed 90°: RB was 25.6 ± 3.8 mm and UB was 34.8 ± 4.8 mm. No significant differences were found in branch lengths between approaches (dorsal vs. volar UB, p = .339; dorsal vs. volar RB, p = .117). All limbs achieved tension-free coaptation.
Neither approach demonstrated superiority in achieving tension-free nerve transfer. Volar permitted immediate identification of ECRB nerve whereas this was only visualized in one dorsal specimen without additional dissection. Overall, the volar approach allows direct coaptation in elbow extension, mimicking maximal physiologic tension for neurorrhaphy. It simultaneously permits additional procedures for pinch reconstruction via single exposure, circumventing limb/microscope maneuvering, dorsal dissection, and increased operative time. Ultimate choice of approach should depend on surgeon familiarity and potential need for additional simultaneous transfers.
外旋肌至骨间后神经（SPIN）转移可重建低桡神经麻痹、不完全 C6 四肢瘫痪和影响 C7-T1 的臂丛损伤的手指/拇指伸展和拇指外展。尚无研究比较背侧与掌侧入路进行 SPIN 转移。本研究比较了两种方法，评估了外旋肌运动支的长度和从任何一种方法进行神经转移的能力。
10 例新鲜冷冻尸体随机分为接受背侧或掌侧入路的 PIN 和外旋肌桡侧和尺侧分支（RB=桡侧，UB=尺侧）。记录外旋肌头的神经支配模式。评估 RB 和 UB 长度、从尺骨茎突到尺骨鹰嘴的前臂长度、无需额外解剖即可观察到伸腕短肌（ECRB）运动神经的情况，以及进行无张力神经转移的能力。
10 个标本中有 9 个标本的外旋肌分支同时支配两个头。掌侧入路所有标本均能观察到 ECRB 神经，而背侧入路仅 1 例。前臂长度无显著差异。肘部伸展时掌侧：平均 RB 长度为 35±7.8mm，UB 为 37.8±9.3mm。肘部伸展时背侧：平均 RB 长度为 30±4.1mm，UB 为 38.8±7.3mm。肘部 90°弯曲时背侧：RB 为 25.6±3.8mm，UB 为 34.8±4.8mm。两种入路的分支长度无显著差异（背侧与掌侧 UB，p=0.339；背侧与掌侧 RB，p=0.117）。所有肢体均实现了无张力的吻合。
两种入路在实现无张力神经转移方面均无优势。掌侧入路可立即识别 ECRB 神经，而背侧入路仅在 1 例标本中无需额外解剖即可观察到。总体而言，掌侧入路可在肘部伸展时直接吻合，模拟神经吻合的最大生理张力。同时，它还允许通过单次暴露进行捏合重建的附加手术，避免了肢体/显微镜操作、背侧解剖和增加的手术时间。最终的入路选择应取决于外科医生的熟悉程度和潜在的同时进行其他转移的需要。
