Neural Ablation and Regeneration in Pain Practice

Abstract

A nerve block is an effective tool for diagnostic and therapeutic methods. If a diagnostic nerve block is successful for pain relief and the subsequent therapeutic nerve block is effective for only a limited duration, the next step that should be considered is a nerve ablation or modulation. The nerve ablation causes iatrogenic neural degeneration aiming only for sensory or sympathetic denervation without motor deficits. Nerve ablation produces the interruption of axonal continuity, degeneration of nerve fibers distal to the lesion (Wallerian degeneration), and the eventual death of axotomized neurons. The nerve ablation methods currently available for resection/removal of innervation are performed by either chemical or thermal ablation. Meanwhile, the nerve modulation method for interruption of innervation is performed using an electromagnetic field of pulsed radiofrequency. According to Sunderland's classification, it is first and foremost suggested that current neural ablations produce third degree peripheral nerve injury (PNI) to the myelin, axon, and endoneurium without any disruption of the fascicular arrangement, perineurium, and epineurium. The merit of Sunderland's third degree PNI is to produce a reversible injury. However, its shortcoming is the recurrence of pain and the necessity of repeated ablative procedures. The molecular mechanisms related to axonal regeneration after injury include cross-talk between axons and glial cells, neurotrophic factors, extracellular matrix molecules, and their receptors. It is essential to establish a safe, long-standing denervation method without any complications in future practices based on the mechanisms of nerve degeneration as well as following regeneration.

Twelve-month analgesia and rescue, by cooled radiofrequency ablation treatment of osteoarthritic knee pain: results from a prospective, multicenter, randomized, cross-over trial

“…Additionally, at the time of this publication, Santana et al produced the only standard RF knee OA series in the literature providing information to 12 months,7 with a mean NRS score reported of 5.8, compared with the mean NRS score of 3.1 in the current CRFA series. While few head-to-head studies exist comparing standard versus cooled radiofrequency directly, such observations are consistent with previous suggestions that the cooling characteristic of CRFA facilitates a larger lesion size than standard RF,28 thus, making it more likely that target nerves will be ablated by the CRFA, and perhaps prolonging the time required to complete nerve regeneration 29. Further study is needed to examine potential differences between the two technologies.…”

Ultrasound-guided pulsed radiofrequency treatment of the cervical sympathetic chain for complex regional pain syndrome

“…In the majority of studies involving RF or PRF treatment of the cervical sympathetic chain, [10–12] the procedure was performed under fluoroscopic guidance. Fluoroscopy can, of course, confirm an accurate needle tip position, but cannot ensure vascular or nerve safety while advancing the needle.…”

“…[9,10] This advantage has led to the increasing application of PRF for the management of chronic pain. [11] The electromagnetic field produced by the rapid electrical pulsation of PRF may have a biological effect on the target nerve.…”

Olfactory Mucosa Mesenchymal Stem Cells and Biomaterials: A New Combination to Regenerative Therapies after Peripheral Nerve Injury

“…Axon and myelin degeneration occur distal to the point of injury by Wallerian degeneration, causing complete denervation (Figure 2). Despite this, once the integrity of the collagenous structures involving the nerve and that function as guides to growth of new axonal buds is maintained, the prognosis of recovery is excellent with a recovery rate of 1 inch per month [35,36]. Neurotmesis results in a total disconnection between the two ends of the injured nerve.…”

“…In ifth-degree lesions, the epineurium is also injured and the formation of end-bulb neuromas is observed. In both cases, recovery without surgical or similar intervention is impossible (Figure 3) [8,36,39].…”