軟骨無形成症に伴う脊柱管狭窄症に対する手術成績―6例報告

Outcomes of Surgery for Spinal Canal Stenosis in Patients with Achondroplasia. Report of Six Cases

　軟骨無形成症に伴う脊柱管狭窄症に対し椎弓切除術を行った6例を報告する．初回手術時平均年齢27歳，術後平均観察期間62カ月，胸腰椎後弯角は術前平均21°であった．全例に椎弓切除を行い，2例に固定術併用，1例に再手術を要した．最終観察時の胸腰椎後弯角は平均25°であった．日本整形外科学会頚髄症治療成績判定基準(JOAスコア)は術前4.4点から最終7.0点であった．6例中4例で成人以降の定期診察がなされておらず，うち2例で治療開始遅延が原因と思われる成績不良を認めた．本症に伴う脊柱管狭窄症は成人以降の発症が一般的であり，患者への啓蒙や定期診察により至適な手術時期を逃さないことが重要である．

　We report six cases in which laminectomy was performed to treat spinal canal stenosis in patients with achondroplasia.　The patients' mean age at the time of the first operation was 27-year-old, and their mean follow-up period was 63 months.　The mean preoperative kyphotic angle was 21 degrees.　Extensive laminectomy was performed in all cases, and it was combined with instrumented fusion in 2 cases.　Reoperation was necessary in one case.　The mean kyphotic angle at the most recent examination was 25 degrees.　The mean JOA score improved from 4.4 points preoperatively to 7.0 points at the most recent follow-up examination.　Four of the patients had not received regular examinations since treatment during their childhood was completed, and serious neurologic symptoms remained in 2 of them because of a delay in the initiation of treatment for spinal canal stenosis.　The symptoms of spinal canal stenosis in patients with achondroplasia usually develop after adulthood.　Based on our experience, it is important to avoid missing the optimal timing for surgery by educating patients and/or continuing regular examinations.