Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery.
Center for Brachial Plexus and Traumatic Nerve Injury, Hospital for Special Surgery; Weill Medical College of Cornell University, New York, NY.
J Hand Surg Am. 2021 Sep;46(9):812.e1-812.e5. doi: 10.1016/j.jhsa.2020.11.022. Epub 2021 Jan 21.
The purpose of the study was to evaluate the utility of the levator scapulae motor nerve (LSN) as a donor nerve for brachial plexus nerve transfer. We hypothesized that the LSN could be transferred to the suprascapular nerve (SSN) or long thoracic nerve (LTN) with a reliable tension-free coaptation and appropriate donor-to-recipient axon count ratio.
Twelve brachial plexus dissections were performed on 6 adult cadavers, bilaterally. We identified the LSN, spinal accessory nerve (SAN), SSN, and LTN. Each nerve was prepared for transfer and nerve redundancies were calculated. Cross-sections of each nerve were examined histologically, and axons counted. We transferred the LSN to target first the SSN and then the LTN, in a tension-free coaptation. For reference, we transferred the distal SAN to target the SSN and LTN and compared transfer parameters.
Three cadavers demonstrated 2 LSN branches supplying the levator scapulae. The axon count ratio of donor-to-recipient nerve was 1:4.0 (LSN:SSN) and 1:2.1 (LSN:LTN) for a single LSN branch and 1:3.0 (LSN:SSN) and 1:1.6 (LSN:LTN) when 2 LSN branches were available. Comparatively, the axon count ratio of donor-to-recipient nerve was 1:2.5 and 1:1.3 for the SAN to the SSN and the LTN, respectively. The mean redundancy from the LSN to the SSN and the LTN was 1.7 cm (SD, 3.1 cm) and 2.9 cm (SD, 2.8 cm), and the redundancy from the SAN to the SSN and the LTN was 4.5 (SD, 0.7 cm) and 0.75 cm (SD, 1.0 cm).
These data support the use of the LSN as a potential donor for direct nerve transfer to the SSN and LTN, given its adequate redundancy and size match.
The LSN should be considered as an alternative nerve donor source for brachial plexus reconstruction, especially in 5-level injuries with scarce donor nerves. If used in lieu of the SAN during primary nerve reconstruction, trapezius tendon transfer for improved external rotation would be enabled.
本研究旨在评估肩胛提肌运动神经（LSN）作为臂丛神经转移供体神经的效用。我们假设 LSN 可以通过无张力吻合和适当的供体与受体轴突计数比转移到肩胛上神经（SSN）或胸长神经（LTN）。
在 6 具成人尸体上进行了 12 次臂丛神经解剖，双侧进行。我们识别了 LSN、副神经（SAN）、SSN 和 LTN。每条神经都准备进行转移，并计算神经冗余。对每条神经的横截面进行组织学检查并计数轴突。我们将 LSN 无张力吻合转移到 SSN 作为目标，然后转移到 LTN。作为参考，我们将远端 SAN 转移到 SSN 和 LTN，并比较转移参数。
在 3 具尸体中，有 2 个 LSN 分支供应肩胛提肌。供体与受体神经的轴突计数比为 1:4.0（LSN:SSN）和 1:2.1（LSN:LTN），用于单根 LSN 分支，当有 2 个 LSN 分支时，比例分别为 1:3.0（LSN:SSN）和 1:1.6（LSN:LTN）。相比之下，SAN 到 SSN 和 LTN 的供体与受体神经的轴突计数比分别为 1:2.5 和 1:1.3。LSN 到 SSN 和 LTN 的平均冗余长度为 1.7cm（SD，3.1cm）和 2.9cm（SD，2.8cm），SAN 到 SSN 和 LTN 的冗余长度分别为 4.5cm（SD，0.7cm）和 0.75cm（SD，1.0cm）。
这些数据支持将 LSN 用作直接神经转移到 SSN 和 LTN 的潜在供体神经，因为其具有足够的冗余和尺寸匹配。
LSN 应该被视为臂丛神经重建的替代神经供体来源，特别是在 5 级损伤且供体神经稀少的情况下。如果在初次神经重建中代替 SAN 使用，将能够进行斜方肌肌腱转移以改善外旋。
