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This Article Full Text Full Text (PDF) All Versions of this Article: 35/11/1940    most recent 0363546507304175v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Request Reprints Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ochiai, N. Articles by Amiel, D. Search for Related Content PubMed PubMed Citation Articles by Ochiai, N. Articles by Amiel, D. Related Collections Animal studies Laser/Radiofrequency energy

Nerve Regeneration After Radiofrequency Application

Nobuyasu Ochiai, MD, PhD^*, James P. Tasto, MD, Seiji Ohtori, MD, PhD, Norimasa Takahashi, MD, PhD, Hideshige Moriya, MD, PhD and David Amiel, PhD^*,

From the ^* Department of Orthopedic Surgery, University of California San Diego, La Jolla, California, San Diego Sports Medicine & Orthopedic Center, San Diego, California, and the Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan

Address correspondence to David Amiel, PhD, Department of Orthopedic Surgery, Connective Tissue Biochemistry, 9500 Gilman Drive, Department 0630, La Jolla, CA 92093-0630 (e-mail: fshepherd{at}ucsd.edu).

Background: Many patients with chronic tendinosis have experienced early pain relief after application of bipolar radiofrequency treatment. It is hypothesized that the mechanism of action may be the acute degeneration and/or ablation of sensory nerve fibers.

Hypothesis: After ablation or degeneration by bipolar radiofrequency, nerve fibers will have the ability to regenerate with time.

Study Design: Controlled laboratory study.

Methods: Eighteen Sprague-Dawley rats were used in this study. These rats were divided into 3 groups (30, 60, and 90 days after bipolar radiofrequency). These rats were treated with 2 points of bipolar radiofrequency applications to the left hindpaws with the Topaz microdebrider device. Right hindpaws were used as the contralateral control. Tissues were processed for neural class III ß-tubulin or calcitonin gene-related peptide immunohistochemistry by using the free-floating avidin biotin complex technique. The numbers of neural class III ß-tubulin–immunoreactive and calcitonin gene-related peptide-immunoreactive nerve fibers in the epidermis were counted and compared with those in the contralateral control.

Results: Although the numbers of nerve fibers demonstrated by both the antibodies of neural class III ß-tubulin and calcitonin gene-related peptide were significantly decreased (P <.0001) until 60 days after bipolar radiofrequency treatment, regeneration of the epidermal nerve fibers occurred 90 days after treatment.

Conclusion: Bipolar radiofrequency treatment induced degeneration of sensory nerve fibers immediately after treatment, but by 90 days posttreatment, there was evidence of complete regeneration.

Clinical Relevance: Early degeneration followed by later regeneration of nerve fibers after bipolar radiofrequency treatment may explain long-term postoperative pain relief after microtenotomy for tendinosis.

Key Words: bipolar radiofrequency • chronic tendinosis • microtenotomy • pain relief