ITB療法において術中カテーテル造影が有用であった2例

Utility of Intraoperative Catheter Myelography during Intrathecal Baclofen Pump Implantation:Report of 2 Cases

Ⅰ．はじめに

　バクロフェン髄注（intrathecal baclofen：ITB）療法は，gamma-aminobutyric acid（GABA）-B受容体アゴニストであるバクロフェンを髄腔内に持続投与し，痙縮を改善させる治療法である．ITB療法では，薬液を充塡したプログラム式輸液ポンプを通常，腹部皮下もしくは腹直筋筋膜下へ留置し，脊髄くも膜下腔へ留置した脊髄側カテーテルとコネクターおよびポンプ側カテーテルで接続することにより，脊髄周囲への持続的な薬剤投与を可能とする．

　本邦では，ITBポンプ植込み術を実施する医師に，eラーニングおよびハンズオン講習の受講が義務づけられている．その甲斐もあり，本邦でのITBポンプ植込み患者における合併症の発生率は，諸外国からの報告と比較し，低いことが確認された⁷⁾．ITBポンプ植込み後に生じる合併症は，ポンプまたはカテーテルに関連するものに大別することができるが，その発生率は後者で高いことが知られている^4,7,8)．

　今回，ITBポンプ植込み術の際に，カテーテル断端から良好な髄液流出を認めたものの，カテーテル先端部が硬膜下腔へ留置されていた2症例を経験した．これらの症例では，術中カテーテル造影を行うことで，脊髄側カテーテルを確実にくも膜下腔へ留置することが可能であったため，その有用性について報告する．

　We report two patients in whom the intrathecal baclofen（ITB）catheter was located in the subdural space, although we had confirmed good outflow of spinal fluid from the spinal catheter. Patient 1 was a woman in her 30s with spastic quadriplegia due to subarachnoid hemorrhage. An ITB pump was implanted, and a good outflow of spinal fluid from the spinal catheter was observed during the surgery. Postoperatively, her spasticity did not improve. Catheter myelography revealed that the spinal catheter was located in the subdural space. Using intraoperative catheter myelography, we corrected the position of the catheter. Patient 2 was a man in his 20s diagnosed with adrenoleukodystrophy. An ITB therapy was performed to improve his spastic gait. Intraoperative catheter myelography showed that the spinal catheter was located in the subdural space, although there was good outflow of spinal fluid from the catheter. Our experience suggests that the outflow of spinal fluid alone should not be used to determine the location of the spinal catheter. Intraoperative catheter myelography is useful for the correct placement of the spinal catheter in the subarachnoid space.