腰部脊柱管狭窄症の最新治療

The Latest Treatment of Lumbar Canal Stenosis

はじめに

　腰部脊柱管狭窄症は腰椎や椎間板，黄色靱帯の変性に伴って脊柱管狭窄が起こり，その結果馬尾神経障害が出現した疾患である。本疾患に伴う下肢痛やしびれなどの症状は，患者のADL（activities of daily living）やQOL（quality of life）へ影響を与えるが，症状のみに関していうと，自然経過の中で一方向性に悪化し続けるとは限らず，本疾患に対する治療は薬物治療や運動療法，ブロック療法等の保存療法が主となることに論を俟たない。しかし，症状の軽快が得られず，患者ADLやQOLへ大きな影響を与えている場合は，外科治療により劇的な症状の改善が得られることも稀ではない。近年，脊椎・脊髄外科領域においてもless invasive surgeryが重要なテーマの1つとして挙げられ，腰部脊柱管狭窄症に対する手術においても，手術アプローチ法に対するさまざまな工夫が行われ，その有用性についての報告がみられる^1）。本稿においては，腰部脊柱管狭窄症に対する外科治療の適応および筆者らが最近行っている手術方法などについて報告する。

Abstract

　Lumbar canal stenosis (LCS) is a degenerative disease involving the lumbar vertebrae,discs,and ligamentum flavum that result in neurological deficit to some extent.　The natural history of symptoms of LCS is highly important because they do not necessarily worsen with progressive degeneration.　Therefore,a observation therapy is adopted for the treatment of this condition.　Although invasive treatment is required for some patients,surgery cannot be performed solely on the basis of radiological findings and careful evaluation of neurological symptoms is necessary.　In the event that spinal surgery is required,it is important to minimize degree of invasiveness; various devices and operative approaches and methods have been developed to this end.　Our strategy for the surgical treatment of LCS involves microscopic decompression via a posterior approach.　In our method,modified bilateral decompression via the splitting of the spinous process using an ultrasonic bone curette (SONOPET),and the results of this approach have been excellent.　Our method is less invasive,facilitates the preservation of the paraspinal muscle,and represents a useful approach to posterior spinal elements.　Our findings indicate that this method involves less muscle damage as compared to other methods.　LCS should be differentiated from conditions other than those involving the spinal canal such as foraminal stenosis and far-out syndrome,piriformis syndrome,and tarsal tunnel syndrome.　The incidence of these conditions is higher than appreciated and they present with neurological deficits similar to observed in LCS.　Here,we report our criteria of operative indications for surger and the procedures that we developed for the treatment of LCS,based on a review of the available literature.