腰部脊柱管狭窄症と腰椎椎間孔狭窄症による神経根症に対して外側開窓と対側からの脊柱管除圧を行った1例

Lateral Fenestration Combined with Spinal Canal Decompression Through Contralateral Laminotomy for Radiculopathy Caused by Lumbar Canal Stenosis and Lumbar Foraminal Stenosis: A Case Report

Ⅰ．はじめに

　近年，画像診断技術の発達により腰椎脊柱管外の病変による神経根症が注目されるようになった．特に椎間孔内の病変により神経根が圧迫されると，障害神経根領域の下肢痛を主とする強い痛みが生じることが多く，しばしば外科的治療を要する．本報告では腰部脊柱管狭窄症（LCS：lumbar spinal canal stenosis）と腰椎椎間孔狭窄症（LFS：lumbar foraminal stenosis）による神経根症を呈した高齢女性に対して，外側開窓による椎間孔内の除圧と対側からの脊柱管除圧を行うことにより，椎弓の連続性を維持しつつ直視下で神経根起始部から椎間孔外まで連続的な神経根の除圧を行うことができた．術前後の経過と文献的な考察を加えて報告する．

　Lumbar canal stenosis (LCS) and lumbar foraminal stenosis (LFS) are frequently observed in elder patients. For patients with radiculopathy caused by both LCS and LFS,surgical manipulations require nerve root decompression from its exit zone to the lateral part of the vertebral foramen,and often need spinal instrumentation. In the present report,we performed a new strategy of surgical decompression without spinal fixation. An 81-year-old woman suffered from bilateral buttock pain,left leg pain and right leg numbness in the L4 and L5 nerve root distribution. MRI and CT scans showed LCS at L3-5 levels and left LFS at L4-5 level. Although the L5 radiculopathy diminished with conservative treatment for 3 weeks,she could not walk due to residual L4 radiculopathy. We tried to perform surgical decompression as follows; the left L4 nerve root was decompressed by lateral fenestration on the left L4 lamina and simultaneously by bilateral spinal canal decompression through right laminotomy for LCS. This method can achieve decompression of the left L4 nerve root from the spinal canal to the vertebral foramen under direct observation while preserving the continuity of the lamina. The patient was relieved from the radicular pain after the operation,and returned to her previous activity of daily living. One-year after the operation,she was free from the radiculopathy,and radiograms showed no fracture in the preserved left L4 lamina. Lateral fenestration combined with bilateral spinal canal decompression through contralateral laminotomy is potentially a surgical option for radiculopathy caused by both LSC and LFS.