Singh Hardeep, Yang Justin S, Wiley Taylor, Judson Christopher, Arciero Robert A, Mazzocca Augustus D, Voss Andreas
Department of Orthopedic Surgery, University of Connecticut Health Center, Farmington, Connecticut, USA.
Department of Trauma Surgery, University Medical Center Regensburg, Regensburg, Germany.
Orthop J Sports Med. 2020 Oct 13;8(10):2325967120954417. doi: 10.1177/2325967120954417. eCollection 2020 Oct.
A musculocutaneous nerve (MCN) injury is a rare complication of the Latarjet procedure. Most of these injuries are neurapraxias and resolve with time; however, permanent injuries can occur. Understanding the anatomy and relationship of the MCN to the coracoid process is essential to prevent injuries.
To provide realistic, in situ-referenced measurements for the Latarjet procedure.
Descriptive laboratory study.
A total of 12 matched-pair cadaveric specimens (24 fresh-frozen shoulders) were dissected. Coracoid osteotomy was performed, and the MCN and its respective twigs were identified. Measurements were made from the coracoid process to the entry site of the nerve twigs and trunk into the coracobrachialis muscle.
Overall, 70.8% of specimens had twigs; however, there was a discrepancy in the presence (41.7%) and number (75.0%) of twigs in the paired specimens. The most proximal twigs were, on average, 33.5 ± 8.1 mm (range, 21.9-47.6 mm) from the coracoid process. The main trunk was, on average, 51.1 ± 14.4 mm (range, 16.7-71.9 mm) from the coracoid process. In 33.3% of specimens, the nerve entered the coracobrachialis at a distance shorter than 5 cm below the coracoid process, and this increased to 91.7% when the twigs were accounted for.
The previously described safe zone of 5 cm below the coracoid process may not be reliable to protect the MCN or its twigs. Using 3 cm would decrease the chances of damaging a twig or the main trunk. In 33.3% of the specimens, the nerve entered the coracobrachialis at a distance shorter than 5 cm below the coracoid process, and this increased to 91.7% when twigs were accounted for.
As the Latarjet procedure is an emerging technique, it is essential to be aware of the anatomic structures and the relation between different neural structures to anatomic points of reference. Therefore, the results of this study add significant information for a safe surgical procedure for the majority of patients suffering from shoulder instability.
肌皮神经（MCN）损伤是Latarjet手术罕见的并发症。这些损伤大多为神经失用症，会随时间自行恢复；然而，也可能发生永久性损伤。了解MCN与喙突的解剖结构及关系对于预防损伤至关重要。
为Latarjet手术提供实际的、原位参照测量数据。
描述性实验室研究。
共解剖12对匹配的尸体标本（24个新鲜冷冻肩部）。进行喙突截骨术，识别MCN及其分支。测量从喙突到神经分支及主干进入肱二头肌短头的入口点的距离。
总体而言，70.8%的标本有分支；然而，配对标本中分支的存在情况（41.7%）和数量（75.0%）存在差异。最靠近近端的分支平均距离喙突33.5±8.1毫米（范围21.9 - 47.6毫米）。主干平均距离喙突51.1±14.4毫米（范围16.7 - 71.9毫米）。在33.3%的标本中，神经在喙突下方距离小于5厘米处进入肱二头肌短头，若将分支计算在内，这一比例增至91.7%。
先前描述的喙突下方5厘米安全区可能无法可靠地保护MCN或其分支。采用3厘米可降低损伤分支或主干的几率。在33.3%的标本中，神经在喙突下方距离小于5厘米处进入肱二头肌短头，若将分支计算在内，这一比例增至91.7%。
由于Latarjet手术是一项新兴技术，了解解剖结构以及不同神经结构与解剖参考点之间的关系至关重要。因此，本研究结果为大多数肩部不稳定患者的安全手术提供了重要信息。
