手根管症候群の手術療法

Operative Treatment for Carpal Tunnel Syndrome

はじめに

　手根管症候群は，手根管内を通過する正中神経がさまざまな原因により圧迫されて発症する絞扼性神経障害である。神経絞扼の原因としては，手の使いすぎなどによる繰り返しの小外傷，手関節近傍の骨折，リウマチ，腔管占拠性病変，長期血液透析によるアミロイドーシス，糖尿病などさまざまなものがあるが，特に原因が特定できない特発例も多い^1）。また，頸椎の疾患においても同様の神経症状を示す場合があるので，頸椎に関連した変形性頸椎症，透析による破壊性脊椎関節症，脊髄腫瘍などと鑑別を要する。また，症例のなかには手根管症候群と頸椎由来病変の両方の疾患に罹患しているケースもあり，その場合には一方のみを治療しても臨床症状がとれないことになるため，正確な診断と患者への十分な説明が重要である。

　筆者は，1986年，“透明な閉鎖性外套管と関節鏡より構成されるUniversal Subcutaneous Endoscope (USE) system”を開発し，この器械を用いた手根管症候群の内視鏡手術を世界に先駆けて開発，施行^2，3）した。そして2007年5月現在までに7,300手に対して手術を行ってきた。本稿では，手根管症候群に対する手術療法の歴史と考え方，さらに20年にわたるUSE systemを用いた鏡視下手根管開放術の経験から，手根管症候群の手術療法の実際について述べる。

Abstract

　Carpal tunnel syndrome is an entrapment neuropathy where the median nerve is compressed inside of the carpal canal.　Causes of this syndrome include repetitive strain, wrist fracture, rheumatoid arthritis, space-occupying lesion, dialysis-related amyloidosis, diabetes mellitus, and in addition, cases with no apparent cause.　Similar symptoms such as numbness, sensory disturbance of the median nerve distribution area and weakness of thenar muscles also occur in patients who suffer from cervical diseases.　In cases where the patient suffers from both carpal tunnel syndrome and cervical disease, the patient's complaints may not disappear if treatment is only performed for one of them.　Therefore, accurate diagnosis of the cause of the symptoms, using electrophysiological test results and/or carpal canal pressure measurement results is essential to the successful treatment of such patients.

　The purpose of operative treatments for carpal tunnel syndrome is to decompress the median nerve.　A variety of operative treatment techniques, i.e., standard open procedure, minimum incision open procedure, one-portal or two-portal endoscopic procedures, etc., are used.　Every procedure has different conditions such as equipment used, operative hand positions, location and size of skin incisions, blind ways or no blind ways, approaches to target tissues, tourniquet usage and others.

　I developed the world's first endoscopic operative procedure for carpal tunnel syndrome using the Universal Subcutaneous Endoscope (USE) system in 1986 and I have operated on over 7,300 hands during these last 20 years.　My technique has been proven by pre- and postoperative carpal canal pressure and intraneural median nerve pressure measurement results as an evidence-based medicine.

　Before an operative method is chosen, the most important thing to consider is whether or not it will safely and completely achieve the purpose as evidence-based medicine with minimal invasion of the patient.