以X光及電腦斷層攝影檢查評估類風濕關節炎病患寰樞椎半脫位之所見

Conventional Radiography and Computerized Tomography in Evaluation of Antlantoaxial Subluxation in Rheumatoid Arthritis

寰樞椎半脫位為類風濕關節炎病患常見之合併症。文獻上報告其發生率為15〜36％，症狀輕重不一，有輕微之頭部酸痛、各種神經症狀、甚至猝死。我們研究民國72年5月至73月4月一年間患有頸部症狀或有關神經徵象之類風濕關節炎病患，計50位。所有病患皆做頸推X光片檢查。38％(19／50)之病人有寰樞椎前後半脫位，10％(5／50)有寰樞椎垂直半脫位。其中14位在中位頸部X光片無前後半脫位，但在前屈位頸部X光片才發現有前後半脫位。因此，頸部前屈X光片在評估寰樞椎半脫位有其必要性。X光片上寰推一齒突距離大於7mm之大部份病人(8／11)及寰椎之脊髓腔管徑小於15mm之所有病人(9／9)皆在電腦斷層攝影上見有脊髓壓迫，5名寰樞椎垂直半脫位病人有4名臨床上有脊髓壓迫之現象。尿液失禁、或手足觸電感、或深部肌腱反射增強、或Babinski徵象等皆表示脊髓有受到壓迫之特異症狀。在前屈頸椎電腦斷層攝影有齒突壓迫脊髓徵象之類風濕關節炎病人，將有較高之神經後遺症之可能。電腦斷層攝影可顯示出骨性及軟組織構造，可用以判定有否壓迫脊髓，然由本文之結果發現僅須用於有下述危險因素時：（一）寰椎一齒突距離大於7mm，（二）寰椎之脊髓腔管徑小於15mm，（三）寰樞椎垂直半脫位，或（四）有脊髓壓迫之特異症狀時。

Atlantoaxial subluxation is not an uncommon complication of rheumatoid arthritis (RA), occurring with a reported frequency of 15~36%. The symptoms vary from neck soreness to neurological complications, and even death. Fifty RA patients in VGH- Taichung with neck complaints or relevant symptoms and signs were studied during May 1983 to April 1984. The radiograph of cervical spine was performed for all patients. Thirty- eight percent (19/50) were found to have atlantoaxial anterior- posterior subluxation, and 10% (5/50) atlantoaxial vertical subluxation. Only 5 patients were detected to have atlantoaxial anterior- posterior subluxation from the neutral view of cervical radiograph. The full flexion view of cervical radiograph was more sensitive in detecting atlantoaxial anterior- posterior subluxation. Spinal cord compression was found by computerized tomography (CT) in 73% (8/11) of RA with a Cl-odontoid distance more than 7mm in flexion view of cervical radiograph; and in 100% (9/9) of RA with a Cl spinal canal diameter less than 15mm. Bladder dysfunction, electric shock sensation, hyperreflexia or Babinski's sign indicated the presence of spinal cord compression. CT evidence of spinal cord compression in flexion view of the C1-C2 region may identify a subset of RA patients at an increasing risk of neurological sequalae. CT could better demonstrate the bone structure, soft tissue, ligament and spinal cord in C1-C2 region. It could be recommended in the presence of relevant symptoms or signs of spinal cord compression or the following findings in flexion view of cervical radiograph: (1) a Cl-odontoid distance more than 7mm, and/or (2) a Cl spinal canal diameter less than 15mm, or (3) atlantoaxial vertical subluxation.