Neuropathic Pain Relief after Surgical Neurolysis in Patients with Traumatic Brachial Plexus Injuries: A Preliminary Report

Abstract

Objective: To evaluate the usefulness of surgical neurolysis for neuropathic pain relief in patients with posttraumatic brachial plexus injury (BPI).

Methods: A prospective, longitudinal, nonrandomized, self-controlled before and after study was performed to evaluate the pain changes according to their intensity using the Visual Analogue Scale (VAS), and the sensory recovery after surgery using the British Medical Research Council (BMRC) scale for sensory recovery. To establish significant changes, a paired T-test was performed, and in order to determine the magnitude of these changes, an effect size was measured. α = 0.05.

Results: Ten patients were included with an average follow-up of 61.9 ± 53.62 months. The main mechanism of injury was vehicular trauma (70%). A significant decrease in pain after the surgical intervention was observed resulting from an average preoperative state according to VAS of 8.4 ± 1.58, to a postoperative state of 3.4 ± 3.27 (59.52%, p = 0.005, Δ = 1.572), added to a mean sensory improvement (25%) from 2.8 ± 1.62 to 3.5 ± 0.97 after surgery according to BMRC, without statistically significant changes (p=0.062), showing a moderate effect size (Δ = 0.413). Almost all patients showed improvement in the continuous and paroxysmal pattern of pain. No postoperative complications were observed. Discussion. These results suggest that in cases of BPI that originates from a compressive syndrome secondary to the posttraumatic fibrosis that surrounds the nerve structures causing strangulation and inducing hypernociception, the use of surgical neurolysis is an appropriate alternative for patients with medically refractory neuropathic pain.

Figure 1

T2 weighted MRI of the brachial plexus showing the onset of the compressive phenomenon after post-traumatic injury, where the left panel shows an initial inflammatory process at an early stage of injury and the right panel image shows the development of fibrosis at a later stage. (a) The arrow points the swelling of the root with increased signals. (b) The image shows a fibrotic process located in the left C5 to C7 brachial plexus trunks (arrow), secondary to the traumatic injury, manifested as pain, symptom explained by the connective tissue that surrounds the nervous structures, generating a compressive phenomenon that originates strangulation of the nerve, inducing hypernociception.

Figure 2

Clinical outcomes. (a) Pain global recovery showed a significant decrease (p=0.005) in postoperative pain intensity with a large effect size (∆ = 1.572). (b) The changes in pain intensity highlight that patient number 6 showed a worsening of his clinical situation after surgical intervention. (c) There was a recovery of sensory function in terms of discriminative touch and deep sensitivity of 25%. However, these changes were not significant (p=0.062). (d) The individualized analysis demonstrated preservation of the sensory status in 50% of the patients, whereas the rest showed an improvement.