Delayed pseudoaneurysm after below-knee amputation

Abstract

A 50-year-old man presented to our outpatient department with a 5-week history of worsening pain and a pulsatile lump within his right below-knee amputation stump. The patient had a previous work-related crush injury to the leg, with 10 operations and eventual below-knee amputation 18 years earlier. Chronic pain in his stump, ascribed to painful neuroma, required three hospital admissions in the previous 2 years under the chronic pain team to titrate opioid, neuromodulatory, and antidepressant medications. Before presentation, the patient reported gradually worsening fit of his prosthesis and increasing reliance on opioid medication for analgesia. Clinical examination of the stump revealed a large, pulsatile, nontender mass on the posterior aspect of his right below-knee stump. Computed tomography angiography confirmed a large pseudoaneurysm measuring 63 mm  67 mm  49 mm filling from the peroneal artery (A/Cover). Digital subtraction angiography verified brisk flow from the end of the peroneal artery filling the pseudoaneurysm (B). Endovascular selective catheterization and Amplatzer plug embolization were performed, although difficulty was encountered in negotiating the sheath into the tortuous peroneal artery. The plug was therefore deployed proximally in the tibioperoneal trunk. Pulsation in the mass ceased, although there was slow filling of the sac on immediate imaging. Delayed digital subtraction angiography 20 minutes after deployment confirmed no contrast material entering the pseudoaneurysm (C). The patient recovered uneventfully with no evidence of stump ischemia and was discharged 1 day after the procedure. DISCUSSIONPostamputation limb pain represents a complex and challenging clinical conundrum. Neurologic and musculoskeletal systems are commonly implicated in residual limb pain; however, pseudoaneurysms are a rare consideration in opioid-resistant pain. 1 Pseudoaneurysm can be manifested suddenly many years after arterial trauma with pain, tenderness, and pulsation, or it may gradually appear, resulting from lowforce blunt trauma. 2 The causative mechanism in this case remains uncertain. Lowgrade trauma within the prosthesis and delayed operative complication are both possible causes of this pseudoaneurysm. Endovascular techniques are a useful treatment approach as illustrated by effective use in this case. Importantly, early imaging of masses within amputation stumps should be considered in cases of nonresolving residual limb pain. REFERENCES 1. Linassi GA, Li Pi Shan RS, El Maadawy SS, Berscheid BB, Rees HG. Case report: pseudoaneurysm causing residual limb pain in a transtibial amputee. J Prosthet Orthot 2008;20:8-11. 2. Bapuraj JR, Thingnam S, Rajak CL. Popliteal artery pseudo-aneurysm following penetrating trauma.