F68. Sensory abnormalities and ultrasound-verified neuromas in lower extremity amputees: An ongoing study

Abstract

Listen

Translate article

Introduction The role of neuromas in stump and phantom limb pain remains unclear. This ongoing study examines whether neuromas are more frequent in amputees experiencing spontaneous and evoked pain after lower extremity amputation than in amputees without pain. Methods In this observational cohort study, amputees with lower and upper extremity amputation are recruited. They answer pain questionnaires and undergo a clinical examination with sensory testing performed within the area of spontaneous pain. Testing includes mapping and registration of sensation elicited by brush, cold and heat (thermorolls 20 °C and 40 °C) and pinprick stimuli (60 g von Frey filament). Neuromas are identified using high resolution (6–18 MHz) ultrasound by an investigator blinded to the patients’ history of pain. Cross sectional areas of the neuromas are measured by the direct tracing method and shear wave elastography is performed. Pressure pain thresholds are measured by an hand held pressure algometer. Results So far, 45 lower and upper extremity amputees have participated in the study (29 men and 16 women; age 25–83 years). Seventy-three percent had at least one neuroma verified by ultrasound. All amputees experienced stump or phantom pain, and the pain was present at least once a month in 16 patients. Only four patients had pain on a daily basis. All amputees experienced abnormal sensations with either hypo- and/or hyperesthesia, and pinprick hyperalgesia was present in seven patients. No significant difference in prevalences of stump pain, intermittent phantom pain and spontaneous phantom pain in patients with and without ultrasound-verified neuromas.No significant difference in prevalence of hypo- or hyperesthesia, hyperalgesia, allodynia and occurrence of Tinel’s sign in patients with and without ultrasound-verified neuromas. Conclusion The recruitment is ongoing. Preliminary data show no association between the occurrence and severity of neither stump nor phantom pain and the presence of neuromas at the amputation site. Sensory abnormalities, pinprick hyperalgesia and brush- and/or cold-evoked allodynia are common findings at the site of the stump, regardless of the occurrence of neuromas.