顺行髓内针内固定术治疗第四、五掌骨骨折的解剖入路研究

Anatomical study of the surgical approach for antegrade intramedullary fixation of the fourth and fifth metacarpal fractures

目的总结顺行髓内针内固定术治疗第四、五掌骨骨折的术后并发症，并进行手术人路的解剖学研究。方法对112例掌骨骨折且接受了顺行髓内针内固定术治疗的患者进行随访，观察术后神经、肌腱的并发症。对16侧成人前臂标本进行解剖学研究，观察尺神经手背支及伸肌腱的走行特点，测量顺行髓内针内固定术治疗第四、五掌骨骨折的人针点到周围神经及肌腱的距离。结果112例中有8．0％（9／112）的患者术后出现手背尺侧半感觉障碍，其中7例完全恢复，2例遗留症状。无肌腱粘连、肌腱刺激或断裂等并发症的发生。解剖学研究显示，第四掌骨人针点距尺神经手背支的中间支约（4．9±1．4）mm，距横支（12．9±2．8）mm，距小指指伸肌腱（2．8±1．5）mm，距小指固有伸肌腱（4．9±1．5）mm；第五掌骨人针点距尺侧支（4．7±2．1）mm，距中间支（5．7±1．5）mm，距小指固有伸肌腱（3．0±1．5）mm。结论第四、五掌骨基底尺背侧为神经、肌腱的“裸区”，是顺行髓内针内固定术治疗第四、五掌骨骨折相对安全的人针区域。但仍要谨慎操作，才能避免损伤。

Objective To summarize the postoperative complications of antegradc intramedullary fixation of the fourth and the fifth metacarpal fractures, and study the anatomic features of the surgical approach. Methods One hundred and twenty two patients with metacarpal fractures who had undergone antegrade intramedullary fixation were followed up and postoperative complications involving nerves and tendons were observed. Anatomical dissection was carried our in 16 formalin embalmed adult cadaver forearms. The course of the dorsal cutaneous branch of the ulnar nerve and the extensor tendons were traced and observed. The distances from the optimal pinning sites for antegrade intramedullary fixation of the fourth and fifth metacarpal fractures to the surrounding nerve branches and extensor tendons were measured. Results Postoperative sensory disturbance on the ulnar side of the dorsal hand occun＇ed in 8.0% （9/112） of the patients. Seven of these patients had complete recovery, whereas the other two still had sensory symptoms. There was no tendon adhesion, tendon irritation or rupture. The distances from the optimal pinning site of the fourth metacarpal to the middle branch and transverse branch of ulnar nerve dorsal cutaneous branch were （4.9 ± 1.4） mm and （12.9± 2.8）mm, respectively. The distances to extensor digitorum of the little finger and extensor digiti minlmi were （2.8 ± 1.5） mm and （4.9 ±1.5 ） mm, respectively. The distances from the optimal pinning site of fifth metacarpal to the ulnar branch, the middle branch and the extensor digiti minimi were（4.7± 2.1）mm,（5.7±1.5）mm and （3.0± 1.5）mm, respectively. Conclusion Both the ulnodorsal aspects of the fourth and fifth metacarpal bases were the relatively safe pinning zones for antegrade intramedullary fixation of metacarpal fractures. Careful manipulation should be done to avoid injury, of the nerve and tendon.