Topical agents for the treatment of chronic pain

Peripheral nerve adjustment for postherpetic neuralgia: a randomized, controlled clinical study

OBJECTIVE

To observe the therapeutic effect of peripheral nerve adjustment for the treatment of postherpetic neuralgia (PHN).

METHODS

One hundred and two patients with PHN were randomly assigned to three groups; the control group (A), the experimental group (B), which was subjected to peripheral nerve adjustment, and patients who received a sham peripheral nerve adjustment, thus serving as a positive control group (C). The patients' Visual Analogue Scale (VAS) and total oral rescue dosage for pain management were recorded at days 1, 3, 7, 14, and 28 following treatment. Quality of life (QOL), 36-Item Short-Form Health Survey (SF-36), and side effects were recorded following treatment.

RESULTS

We observed that the average VAS score was significantly lower in the treatment group (B) than in the control groups A and C following treatment (P < 0.05). In addition, the QOL and SF-36 scores for group B improved substantially following treatment compared to groups A and C, and this effect was maintained up to 180 days after treatment (P < 0.05). The average dosage of pain medication was also lower in group B, compared to groups A and C, following treatment (P < 0.05).

CONCLUSIONS

We conclude that peripheral nerve adjustment can relieve PHN pain and improve patients' quality of life. The possible mechanisms involved may include the reduction of both peripheral and central sensitization, the modulation of nerve plasticity, and an increase in endogenous analgesic molecules.

Modulating pain in the periphery: gene-based therapies to enhance peripheral opioid analgesia: Bonica lecture, ASRA 2010

This article provides a brief overview of earlier work of our group on the peripheral signaling of pain, summarizes more recent studies on the role of opioids in chronic neuropathic pain, and speculates on the future of gene-based therapies as novel strategies to enhance the peripheral modulation of pain. Neurophysiologic and psychophysical studies have revealed features of primary afferent activity from somatic tissue that led to improved understanding of the physiology and pathophysiology of pain signaling by nociceptive and nonnociceptive fibers. The demonstration of peripheral opioid mechanisms in neuropathic pain suggests a potential role for these receptors in the modulation of pain at its initiation site. Our work has focused on characterizing this peripheral opioid analgesia in chronic neuropathic pain such that it can be exploited to develop novel and potent peripheral analgesics for its treatment. Ongoing research on virus-mediated gene transfer strategies to enhance peripheral opioid analgesia is presented.