Mahmoud Amir-Ala, Mahmoud Amir-Ali, Bahouth Sara M, Wieschhoff Ged G, Ferrone Marco, Helliwell Lydia A, Mandell Jacob
Harvard Medical School, Boston, MA, USA.
Department of Radiology, UC Davis Health, Sacramento, CA, USA.
Skeletal Radiol. 2025 Aug 5. doi: 10.1007/s00256-025-04994-3.
Patients with extremity sarcomas may require amputation when limb salvage surgery is not possible. Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are procedures that can reduce neuroma formation, though neuromas can still occur. This study aims to describe the MRI characteristics of TMR/RPNI, examine changes in neuromas over time, and differentiate these from sarcoma recurrence on MRI.
All patients at our institution between 2013 and 2024 who underwent upper or lower extremity amputation due to sarcoma, underwent TMR/RPNI, and had follow-up MRI imaging were included. Two radiologists evaluated the incidence and appearance (size, signal characteristics, enhancement pattern, morphology) of neuromas and their evolution. Statistical analysis employed the chi-squared test and McNemar's test.
Sixty-two TMRs and 46 RPNIs were performed in 26 patients (7 upper, 19 lower extremity amputations). Seven patients had TMR-only, 7 had RPNI-only, and 12 had both, with an average follow-up of 517 days (range 91-1705 days). MRI identified nodular, T2 hyperintense, enhancing foci averaging 0.8 cm in diameter (range 0.3-2.0 cm) at 44% of nerve surgery sites and in 73% of patients at initial follow-up. These foci, presumed to represent neuromas, decreased over time (p < 0.001) with a significant reduction in nodule size for TMR-only patients (p = 0.007). Two recurrences showed increasing irregular nodule size.
TMR and RPNI procedures show T2 hyperintense nodules on the first follow-up MRI, which decrease in incidence over time. TMR significantly reduces neuroma size. Increases in nodule size should prompt concern for recurrence.
当保肢手术无法进行时，肢体肉瘤患者可能需要截肢。靶向肌肉再支配（TMR）和再生周围神经接口（RPNI）是可以减少神经瘤形成的手术，不过神经瘤仍有可能发生。本研究旨在描述TMR/RPNI的MRI特征，观察神经瘤随时间的变化，并在MRI上将其与肉瘤复发相鉴别。
纳入2013年至2024年期间在本机构因肉瘤接受上肢或下肢截肢、接受TMR/RPNI且有MRI随访成像的所有患者。两名放射科医生评估神经瘤的发生率和表现（大小、信号特征、强化方式、形态）及其演变情况。统计分析采用卡方检验和 McNemar 检验。
26例患者（7例上肢截肢、19例下肢截肢）进行了62次TMR和46次RPNI。7例患者仅接受了TMR，7例仅接受了RPNI，12例两者都接受了，平均随访517天（范围91 - 1705天）。MRI在44%的神经手术部位和73%的患者初始随访时发现结节状、T2高信号、强化灶，平均直径0.8厘米（范围0.3 - 2.0厘米）。这些病灶推测代表神经瘤，随时间减少（p < 0.001），仅接受TMR的患者结节大小显著减小（p = 0.007）。两次复发表现为结节大小不规则增加。
TMR和RPNI手术在首次随访MRI上显示T2高信号结节，其发生率随时间降低。TMR显著减小神经瘤大小。结节大小增加应警惕复发。
