Corder Brittany N, Sullivan John M, Humphries Laura S, Walker Marc E
Division of Plastic and Reconstructive Surgery, University of Mississippi Medical Center, Jackson, MS.
J Hand Surg Glob Online. 2023 Aug 12;5(6):834-836. doi: 10.1016/j.jhsg.2023.07.004. eCollection 2023 Nov.
Anatomical variations within Guyon's canal such as an accessory abductor digiti minimi are described as causes of ulnar nerve compression. Here we present a unique case of delayed ulnar neuropathy following treatment of left fourth metacarpal base fracture with percutaneous pinning fixation and an uncomplicated two month postoperative course. He returned with new ulnar sensory loss and motor weakness. EMG demonstrated nerve compression with CT identifying an accessory abductor digiti minimi in Guyon's canal. Following Guyon's canal release with partial accessory muscle resection, there was immediate sensory and progressive motor recovery with resolution of clawing. Delayed compression by an accessory abductor digiti minimi following trauma has not been described, suggestive of double-crush phenomenon. The accessory muscle was an asymptomatic variable (first "crush") and with the second "crush" of post-surgical changes resulting in pathological nerve compression. With delayed onset ulnar neuropathy after trauma, surgeons should consider possible accessory structures.
盖氏管内的解剖变异，如小指副外展肌，被认为是尺神经受压的原因。本文报道了一例独特的病例，患者因左侧第四掌骨基底骨折接受经皮穿针固定治疗，术后两个月恢复顺利，但随后出现迟发性尺神经病变。患者再次就诊时出现新的尺神经感觉丧失和运动无力。肌电图显示神经受压，CT检查发现盖氏管内有小指副外展肌。在进行盖氏管松解并部分切除副肌后，患者感觉立即恢复，运动功能逐渐改善，爪形手消失。创伤后由小指副外展肌导致的迟发性压迫尚未见报道，提示存在双压榨现象。副肌是一个无症状的变异因素（第一次“压榨”），而手术改变导致的第二次“压榨”造成了病理性神经压迫。对于创伤后迟发性尺神经病变，外科医生应考虑可能存在的附属结构。
