LAUSR

Postamputation stump and phantom pain is highly prevalent, but remains a difficult condition to treat. The underlying mechanisms are not fully clarified, but growing evidence suggests that changes in afferent nerves, including the formation of neuromas, play an important role. The main objective of this cross-sectional study was to investigate if ultrasound-verified neuromas swellings are more frequent in amputees with postamputation pain than in amputees without pain (primary outcome). Sixty-seven amputees were included. Baseline characteristics including the frequency and intensity of spontaneous stump and phantom pain, were obtained, and sensory characteristics and evoked responses were assessed. A high-frequency ultrasound examination of the amputated extremity was performed to obtain information on the presence, size, and elasticity of swollen neuromas and pressure pain thresholds. Swollen neuromas were present in 53 (79.1%) of the 67 amputees included in the study, in 47 (82.5%) out of 57 amputees with pain and in 6 (60.0%) out of 10 amputees without pain (P = 0.2). No difference was found in stump pain intensity (P = 0.42) the last week or in phantom pain intensity the last month (P = 0.74) between amputees with and without swollen neuromas. Our findings suggest that it is not the presence of swollen neuromas itself that drives postamputation pain. However, changes in the transected nerve endings may still be crucial for driving postamputation pain as a positive Tinel´s sign was significantly more frequent in amputees with pain, irrespectively of the degree of neuroma swelling.