後方除圧術後に重度の対麻痺を発症した上位胸椎後縦靱帯骨化症2例の検討

Severe Neurological Deterioration after Posterior Decompression Surgery for Ossification of the Posterior Longitudinal Ligament (OPLL) in the Upper Thoracic Spine. Report of Two Cases

　上位胸椎の後縦靱帯骨化症(OPLL)に対する後方除圧術後に，重度の対麻痺を生じた2例を経験した．2例ともに第1-3胸椎(T1-3)高位の嘴型の骨化が原因病巣であった．症例1は広範椎弓切除により後弯が軽度増強し脊髄が前方から圧排されたこと，症例2は脊髄の後方移動が不十分で骨化巣と脊髄の接触が解除されなかったことが麻痺の原因と考えられた．これらの症例に追加の胸骨縦割進入前方除圧固定術を施行し麻痺の改善を認めた．

　Ossification of the posterior longitudinal ligament (OPLL) causes myelopathy that is often treated by posterior descompression surgery.　We report two cases in which paraplegia developed after posterior surgery for OPLL in the upper thoracic spine.　Patient 1 was a 52-year-old woman with multiple level OPLL and ossification of the yellow ligament (OYL) in the upper thoracic spine.　She complained of weakness of both lower limbs before surgery.　Paraplegia was noted three days postoperatively.　Patient 2 was a 61-year-old woman with OPLL of the cervical and thoracic spine.　Posterior decompression surgery with corrective fusion was performed.　Paraplegia developed eight days postoperatively.　Subtotal corpectomy and fusion was effective in restoring motor function in both cases.　Both patients had beak-type OPLL in the upper thoracic spine.　Anterior corpectomy and fusion was concluded to be feasible salvage surgery for patients who develop paraplegia as a complication of posterior decompression surgery.