Chronic Neuropathic Pain of Brachial Plexus Avulsion Mistaken for Amputation Stump Pain for 36 Years: A Case Report

Abstract

Following an amputation of the extremities, chronic neuropathic pain and discomfort, such as phantom limb pain (phantom pain), phantom sensation, and stump pain may occur. Clinical patterns of phantom pain, phantom sensation, and pump pain may overlap and these symptoms may also exist in one patient. Serious trauma to the upper limbs can result in brachial plexus avulsion (BPA). If BPA occurs at the same time as severe trauma of the upper extremity and the amputation of the upper limb is performed, chronic neuralgia caused by BPA may be mistaken for chronic amputation pain, such as phantom limb pain or stump pain. No major treatment advances in phantom pain have been made. However, unlike phantom limb pain, chronic neuropathic pain caused by BPA can be effectively treated with dorsal root entry zone lesioning (DREZ)-otomy. We report a patient who suffered for 34 years because the neuralgia caused by BPA was accompanied by an amputation of the arm, and so was thought to be amputation stump pain rather than BPA pain. The patient's chronic BPA pain improved with microsurgical DREZ-otomy.

Keywords: Amputation; Brachial plexus; Brachial plexus neuropathies (avulsion); Dorsal root entry zone (DREZ); Nerve root avulsion; Neuropathic pain.

FIGURE 1. Clinical photographs and radiological images showing the amputation location and the area of pain. (A) Photograph showing the amputation stump on the right shoulder. The stump was well-padded and healthy. Chronic pain was located in the area inside the dotted line. (B) Axial (left) and coronal (right) myelographic computed tomographic images show the absence of the dorsal root (white arrowhead) and atrophy of the right-sided hemicord (white arrow) at the C6/7 level. The left-sided C7 root (black arrow) is normal. (C) The axial T2-weighted magnetic resonance imaging image show the loss of the dorsal root (white arrow) and atrophy of the right hemicord at the C6/7 level. In the right C6/7 foramen, widening of the subarachnoid space, suspicious of pseudomeningocele (white arrow head), suggesting brachial plexus avulsion is identified.

FIGURE 2. Intraoperative photographs during DREZ-otomy and intraoperative monitoring for brachial plexus avulsion pain. (A) Intraoperative photograph showing avulsion of the right-sided dorsal roots. There is no dorsal root in the right dorsolateral sulcus (white arrows) and grayish-yellow discoloration is observed along the avulsed dorsolateral sulcus. Normal dorsal roots (black arrows) are observed in the left dorsolateral sulcus. (B) Intraoperative photograph showing DREZ-otomy with fine-tipped bipolar coagulation. The lower level dorsolateral sulcus (white arrows) on the left side of the photograph is in the coagulation state, and the sulcus on the right side (black arrow) in the picture is still in the state before coagulation. (C) The motor-evoked potentials and somatosensory-evoked potentials in the right leg did not change significantly during surgery.

DREZ: dorsal root entry zone.