HISTOCHEMICAL ANALYSIS OF TENOSYNOVIUM FROM PATIENTS WITH AND WITHOUT CARPAL TUNNEL SYNDROME

Participants: D. Louis, M. Moalli, P. Jebson, M. McDermott, J.M. Hall

Keywords: carpal tunnel syndrome, tenosynovium, histochemical analysis

Introduction

Carpal tunnel release has become one of the most frequently performed operations on adults in the United States, with over 200,000 surgical procedures per year. In 1988 it represented the tenth most commonly performed procedure in terms of dollars spent under Medicare Part B. Despite the common occurrence of carpal tunnel syndrome, the pathophysiology of the underlying process is not completely understood. The tenosynovium is frequently found to be thickened at the time of surgery. We have previously studied the histologic features of carpal tunnel tenosynovium biopsied at the time of carpal tunnel release. However, the histologic presentation of "normal" tenosynovium (tenosynovium in the absence of carpal tunnel syndrome) is unknown. This study proposes to compare normal tenosynovium obtained from otherwise healthy adults who are having surgery of the hand or forearm not related to carpal tunnel syndrome to tenosynovium obtained from otherwise healthy patients with carpal tunnel syndrome. The purpose of this study is to determine whether a quantifiable difference exists between "normal" tissue and tissue from patients with carpal tunnel syndrome. Microscopic analysis of such tissue is limited. We will use histochemical analysis to determine whether there are differences in issue components in people with carpal tunnel syndrome compared to controls.

Materials and Methods

This prospective study will document the histologic characteristics of normal tenosynovium in health adults who do not have carpal tunnel syndrome and who are having surgery of the forearm or hand. The tissues obtained from these subjects will be compared with the tissues from subjects with known carpal tunnel syndrome. The primary outcome variable is the difference between these two groups of tissues as evidenced by fibrous metaplasia with increased type III collagen, TGF-B and IGF-1 expression in carpal tunnel syndrome patients. Histologically "normal" tissue will be characterized by the absence of these matrix components. It will consist of synoviocytes dispersed with a membranous/fatty stroma

TGF-B is a growth factor associated with scar tissue formation. The possible role of scar tissue in the development of carpal tunnel syndrome was suggested by Shuind¹ Once there is strong evidence that the proposed cytokines and growth factors are present in synovial tissue from patients with CTS, the next step will be to evaluate genetic regulation of the process. This will be accomplished by performing Northern analysis and probing for candidate genes which regulate cytokine expression. By utilizing a hierarchical approach, the pathogenesis of CTS can be sequentially dissected, with the potential for pharmacological intervention at any of the regulatory steps identified as the evaluation proceeds.

Progress

IRB approval was obtained for this study and thirty-three subjects have been enrolled to date. An additional seventeen control subjects are needed to complete the study.

References

[1] Shiund F, Bentura M, Pasteels JL: Idiopathic carpal tunnel syndrome: Histologic study of flexor tendon synovium. J Hand Surgery May 1990; 15A(3):497-503.