Value of high-frequency ultrasonography in diagnosis of proximal radial nerve injuries associated with humeral shaft fractures / 中华创伤杂志

ABSTRACT

Objective:To evaluate the diagnostic accuracy and application value of high-frequency ultrasonography in proximal radial nerve injuries associated with humeral shaft fractures.Methods:A retrospective case series study was performed for 19 patients with proximal radial nerve injuries associated with humeral shaft fractures treated in Huashan Hospital Affiliated to Fudan University from August 2014 to September 2020. The were 17 males and 2 were females，with the age range of 16-55 years ［（38.1±12.7）years］. Of all，11 patients were injured at the left side and 8 at the right side. All the patients had histories of traumatic humeral shaft fracture and were treated in other hospitals，including internal fixation in 17 patients，external fixation in 1 and internal fixation combined with external fixation in 1. All patients underwent radial nerve exploration surgeries，among which 8 had high-level radial nerve release and 11 had high-level radial nerve suture or graft transplantation. All patients underwent high-frequency ultrasound examination before surgery. The ultrasonographic characteristics of the radial nerve were recorded，including the continuity of the epineurium，honey-comb structure on the transversal section，neuromas on the longitudinal section and external scar or callus or metal fixation compressing the nerve. The injury type and neural continuity of each radial nerve were evaluated. The radial nerves of type Ⅰ，type Ⅱ，type Ⅲa ，type Ⅲa ，type Ⅲb and type Ⅳ appeared as normal，swelling，short-segment compressed，neuroma-like and ruptured，respectively. Taking the intraoperative findings as the gold standard，the diagnostic coincidence rate，sensitivity，specificity，positive predictive value and negative predictive of high-frequency ultrasound were analyzed in diagnosis of proximal radial nerve injuries associated with humeral shaft fractures.Results:According to ultrasonographic characteristics，proximal radial nerve injuries were classified into 4 types in 5 subtypes. It was confirmed by surgeries that there were 1 patient with type Ⅱ，4 with type Ⅲa，1 with type Ⅲb and 13 with type Ⅳ，with no type Ⅰ. The diagnostic coincidence rate of high-frequency ultrasound was 89%. The diagnostic coincidence rate of type Ⅱ，type Ⅲa，type Ⅲa，type Ⅲb and type Ⅳ was 100%，100%，100% and 85%，respectively. The sensitivity of high-frequency ultrasound for evaluating the neural continuity was 75%，the specificity was 100%，the positive predictive value was 100%，the negative predictive value was 85%.Conclusions:The high-frequency ultrasound has a relatively high sensitivity and specificity in diagnosis of proximal radial nerve injuries associated with humeral shaft fractures，which can provide relatively accurate morphological information for clinical diagnosis and treatment.