Ultrasound assessment of structural changes in peripheral nerves of extremities after amputation in case of gunshot injury

BACKGROUND: Considering the large number of limb amputations in war-related gunshot wounds, early diagnosis of terminal neuromas is important to provide appropriate limb replacement. AIM: The aim of this study was to determine the feasibility of ultrasound in evaluating peripheral nerve endings and detecting terminal neuromas in patients after limb amputation due to gunshot trauma. MATERIALS AND METHODS: A total of 71 patients (men aged 20–57 years old) underwent ultrasound examination of 179 peripheral nerves. The examination was conducted according to standard technique using the ACUSON S2000 scanner (Siemens Healthineers, Germany) with a linear transducer with a frequency of 7–17 MHz, after setting the program of musculoskeletal examination. The cause of amputation was gunshot trauma. The duration of gunshot trauma ranged from 11 to 362 days, while the period between surgical intervention and the examination ranged from 11 to 340 days. The indication for the examination was pain in the limb stumps. RESULTS: A comprehensive examination of 179 peripheral nerves revealed 149 injured endings that were subjected to further evaluation. The distribution of lesion frequency revealed that the shoulder level was the most affected area in the upper extremities, while the thigh was the most affected area in the lower extremities. Notably, lesions on the left side were more prevalent in both cases. All observed changes in the endings were classified into three distinct groups: Group 1 (60%) comprised structural changes without signs of terminal neuroma. Group 2 (25%) consisted of structural changes with terminal neuroma. Group 3 (15%) included structural changes with potential (forming) terminal neuroma. In the absence of a terminal neuroma, ultrasound findings may include thickening of the nerve ending with preserved fascicular structure, decreased echogenicity, and increased vascularization of the nerve ending in color Doppler mapping. The ultrasound findings suggestive of a potential terminal neuroma include the following: the same and the presence of a globular hypoechogenic mass emanating from the nerve ending, the absence of differentiation into fasciculi in the mass, the latter not occupying the entire cross-sectional area of the nerve ending, and the mass being avascular on color Doppler mapping. The ultrasound findings of a formed terminal neuroma include the following: a club-shaped or globular hypoechogenic mass exceeding the cross-sectional area of the nerve proximally by 2 or more times, emanating from the nerve ending; absence of differentiation into fasciculi in the formation; the formation occupying the entire cross-sectional area of the nerve ending and being avascular in color Doppler mapping. The timing of terminal neuroma formation was observed to occur on average 109.9 days (14–362) after gunshot trauma and 98.2 days (14–340) after surgical intervention. The formation of terminal neuromas was observed on average 153.3 days (31–341) after gunshot trauma and 139.5 days (14–327) after surgical intervention. CONCLUSIONS: Ultrasound examination is an effective method of detecting terminal neuromas as a potential cause of pain syndrome in amputated limbs in gunshot trauma. It is recommended that ultrasound diagnosis of terminal neuromas be performed no earlier than 31 days after surgical intervention, and that ultrasound monitoring in dynamics be conducted.