桡骨交锁髓内钉近端锁钉安全性的基础与临床研究

The anatontic and clinic study of locking screw insertion site in locked intramedullary nail of the radius

目的研究桡骨交锁髓内钉近端锁钉在3种不同入路的情况下与桡神经深支(posterior interosseous nerve,PIN)的解剖关系,确定锁钉安全人路及位置,探讨桡骨交锁髓内钉临床应用的疗效。方法将9具成人上肢尸体标本随机分成三组,按照标准桡骨交锁髓内钉锁钉手术方法,在不暴露桡神经深支的情况下分别从3种不同入路(前侧入路、外侧入路、后侧入路)进行锁钉,然后解剖出桡神经深支,测量和观察锁钉与桡神经深支的关系。在此基础上临床应用22例(单纯桡骨骨折8例,盖氏骨折3例,尺、桡骨双骨折11例),全部采用外侧手术入路锁钉。结果在前臂中立位时,外侧入路锁钉与桡神经深支的最短距离平均为5．8mm(前侧入路平均为1．7mm,后侧人路平均为1．2mm)。前臂过度旋前位时桡神经深支的安全区域为[(50．8±6．2)mm,(?)±s,下同],前臂过度旋后位时桡神经深支的安全区域为(30．4±5．8)mm。术后22例均未发生桡神经深支损伤的症状。术后随访2～16个月,平均9个月,桡骨愈合时间为8～24周,平均12周。按照Anderson评分标准评定：优13例,良6例,可2例,失败1例。结论桡骨交锁髓内钉近段锁钉采用前臂过度旋前位,于桡骨小头外侧微创小切口入路进行锁钉对桡神经损伤的机率最小。

Objective To assess the relation of the posterior interosseous nerve （PIN） to the locking screw insertion site in locked intramedullary nail of radius from a standard anterior, posterolateral and posterior approach, and discuss the feasibility of using locked intmmedullary nail for treatment of radius fractures. Methods Locking screw insertion was simulated on 9 fresh cadaver arms via standard anterior, posterolateml and posterior approach, with 3 cadavers each. Blind subperiosteal dissection was performed distally until standard proximal locking screw was inserted. Dissection of the radial nerve was then performed to measure the distance between the screw and file deep branch. Intramedullary nailing of fractured radius was carried out in 22 cases via a lateral approach （ 8 cases of radius fracture, 3 cases of Galeazzi fracture, and 11 cases of both bone fracture of the forearm）. Results The minimum distance between the locking screw and PIN was 5.8 mm with the forearm in neutral position from a lateral approach, while that from an anterior approach or a posterolateral approach being 1.7 mm and 1.2 mm respectively. The safety zone of PIN spanned （50.8 ± 6.2） mm with forearm at extreme pronation and （ 30.4 ± 5.8） mm at extreme supination. There was no PIN injury in postoperative follow-up of the 22 clinical cases ranged from 2 to 16 months with an average of 9 months. Bone union occurred from 8 to 24 weeks, with an average of 12 weeks. According to Anderson scoring, 13 cases were graded excellent, 6 cases good, 2 cases fair, and 1 case poor. Conclusion Insertion of the proximal locking screw via a small incision posterolateml to the radial head with the forearm in 90°pronation renders PIN at the lowest risk of injury.