Phantom Remodeling Effect of Dorsal Root Entry Zone Lesioning in Phantom Limb Pain Caused by Brachial Plexus Avulsion

Abstract

Background: Dorsal root entry zone (DREZ) lesioning has been reported to be effective for phantom limb pain caused by brachial plexus avulsion pain. Most reports on DREZ lesioning for brachial plexus avulsion pain have focused on the results of pain relief without a detailed description of phantom sensations following DREZ lesioning. Materials and Methods: Two patients (1 with amputation and the other nonamputated) with chronic intractable phantom limb pain caused by brachial plexus avulsion underwent DREZ lesioning on the avulsed segments of the cervical spinal cords. Changes of the phantom limb were observed. Results: Immediately following DREZ lesioning, the phantom limb pain disappeared in the amputee, the phantom arm was shortened and the phantom hand disappeared. The other patient with the nonamputated arm reported an immediate 50% reduction in the size of the phantom hand, and pain relief was up to 70% of the preoperative phantom limb pain. There was no further change in the phantom arm and hand during the follow-up of 1.5-2 years. Conclusions: The phantom arms and hands showed a prompt shortening and reduction in size, rather than a disappearance, following successful DREZ lesioning in patients with chronic phantom limb pain caused by brachial plexus avulsion.

Intraoperative Neurophysiological Monitoring (Motor and Somatosensory Evoked Potentials) in Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain

“…It is well known that the absence of an mMEP is not necessarily associated with postoperative motor deficits [9,10,11,12]. However, regarding the high incidence of postoperative neurologic deficits (100%) in patients with a >50% decrease in mMEP amplitude in the ipsilateral extremities, we speculate that this may be the criterion because of the small number of patients in this study ( n = 9), and it may have been caused by underlying atrophic changes of avulsed cervical spinal cords, which render the spinal cords easily susceptible to additional heat lesions during DREZ lesioning [1,5,7]. …”

“…The patients were ventilated with oxygen and nitrous oxide up to a concentration of 50%. A muscle relaxant was used during intubation, and in some patients an additional bolus of muscle relaxant was given to prevent possible muscle artifacts on the MEP [5,6]. Opening of the dura through a C 4 -T 1 hemilaminectomy led to detection of an avulsion of the dorsal roots, and severe arachnoid adhesion and pseudomeningoceles were carefully dissected under microscopy.…”

“…In the last 6 consecutive patients (patients No. 4-9), microsurgical DREZotomy was performed using a pair of fine-tipped, bipolar coagulation forceps specially designed for this application [5,6]. After exposure and identification of the avulsed segments, neurophysiological monitoring was performed to assess the safety during dissection of the dorsolateral sulcus and DREZ lesioning.…”

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

“…Intraoperative neurophysiologic monitoring of the motor evoked potential (MEP) and the somatosensory evoked potential (SEP) of ipsilateral and contralateral arms and legs were performed. 18) The avulsed posterolateral sulcus (C7–T1) was identified under microscopic vision. After opening the pia mater of the avulsed sulcus, coagulation of grayish-yellow-colored gliotic dorsal horn was performed with fine-tipped, bipolar coagulation forceps specially designed for the application ( FIGURE 2A & B ).…”

Phantom limb pain: peripheral neuromodulatory and neuroprosthetic approaches to treatment

“…Complete recovery has been observed after neurectomy in patients experiencing PLP and anecdotal evidence suggests that formation of post‐amputation neuromas could be prevented by ligating the nerve as proximally as possible . Several studies have also detailed the impact of cordotomy, tractotomy, and dorsal root entry zone (DREZ) lesioning on relieving PLP. DREZ lesioning has been used as an effective treatment for relieving intractable pain due to root avulsion and brachial plexus avulsion injuries, but its the effects on PLP have varied.…”