L5-S1椎体骨棘を伴った椎間孔外狭窄に対する後方除圧術の成績

Surgical Results for Posterior Decompression for Extraforaminal Stenosis Associated with Osteophytes of L5-S1 Vertebral Bodies

　L5-S1椎体骨棘を伴った椎間孔外狭窄症例に対する顕微鏡あるいは内視鏡を用いた後方除圧術の成績について検討した．対象は8例（男6例，女2例，平均年齢61歳）で，全例強度の下肢痛を呈していた．手術は後方からの仙骨翼部分切除を行った．5例は顕微鏡下に，3例は内視鏡下に手術を行った．全例で術後下肢痛の消失あるいは軽減が得られたが，顕微鏡下に手術を行った1例で再発を生じ，後方除圧固定術が追加された．明らかな手術合併症は認めなかった．L5-S1椎体骨棘を有する椎間孔外狭窄症例に対する後方アプローチによる仙骨翼部分切除は，十分な除圧範囲の確保に留意すれば，低侵襲で有用性の高い手術法と思われた．

　The L5 spinal nerve may be entrapped at the extraforaminal neural tunnel consisting of the lumbosacral ligament, the L5 spinal body, and the sacral ala. We treated 8 patients―6 men and 2 women (mean age, 61 years) with L5 radiculopathy due to prominent osteophytes at the L5-S1 vertebral bodies narrowing the lumbosacral tunnel in a posterior approach. All patients had severe leg pain and neurogenic claudication. Decompressive surgery was conducted by resecting the sacral ala via a posterior approach. Surgical microscopy was used in 5 and endoscopy in 3. All patient had immediate pain relief postoperatively. One had symptoms recur 1 year after surgery and underwent revision by posterior lumbar interbody fusion. Partial resection of the sacral ala in a minimally invasive posterior approach using microscopy or endoscopy is thus effective in treating extraforaminal entrapment of the L5 spinal nerve.