松田 正道¹, 渡辺 五朗¹, 橋本 雅司¹, 宇田川 晴司¹, 奥田 近夫², 竹内 和男²

Masamichi MATSUDA¹, Goro WATANABE¹, Masaji HASHIMOTO¹, Harushi UDAGAWA¹, Chikao OKUDA², Kazuo TAKEUCHI²

¹虎の門病院消化器外科, ²虎の門病院消化器科

¹Department of Surgery, Toranomon Hospital, ²Department of Gastroenterology, Toranomon Hospital

キーワード : intra-abdominal abscess, laparoscopic cholecystectomy, spilled stones, ultrasonography

腹腔鏡下胆嚢摘出術 (Laparoscopic cholecystectomy：以下LC)は胆石症の標準的治療法として広く定着した. LCでは手術中に胆嚢を損傷する危険性が高く, 小結石あるいは胆汁が腹腔内へと散布され, 後に膿瘍や肉芽が形成されることがある. この事実はLCの術後合併症として外科医にはある程度知られるようになってきたが, 広く一般に認知されたとは言い難い. 今回は当科で経験したLC術後膿瘍の超音波像を検討し, その形態に関して評価を加えた. 使用装置は日立 EUB-525, ALOKA-SSD-5500 (3.75 MHz)である. 当科で経験したLC後の遺残膿瘍は7例で, うち5例が当科でのLC施行例であった. これは1990年から2001年までのLC施行例の0.2% (5/2036)に相当した. 7例中3例は有症状例として発見されたが, 4例は術後の経過観察における腹部超音波検査で発見されたものであった. 5例に手術を施行し膿瘍を摘除した. 膿瘍は右横隔膜下あるいは肝右葉下面と右腎上極の間に存在し, US上20〜58 mmまでの楕円〜類円形の腫瘤像として描出された. いずれも周囲との境界は明瞭で, 多くは後方エコーの増強と外側音響陰影を伴っていた. 腫瘤の辺縁は平滑で, 一層の高エコー層を有し, 内部は低い充実性パターンを呈していた. また内部に音響陰影を伴う数mm大の高エコー域を数個認めた. 今回の検討から, LCの術後には散石膿瘍・肉芽が発生することを念頭に置き, ことに術中胆嚢損傷を生じた場合, 明らかな結石の散乱がなくとも, USを中心とした慎重な経過観察が必要と考えられた.

Spillage of stones into the abdominal cavity resulting from perforation of the gallbladder is one of the common complications of laparoscopic cholecystectomy. Although many surgeons know that stones left in the abdominal cavity can cause late visceral abscess requiring surgical treatment, the sonographic features of such abscesses have not yet to be thoroughly investigated. We investigated the sonographic features of intra-abdominal abscesses caused by spilled stones after laparoscopic cholecystectomy using Hitachi Model EUB-525 (3.5 MHz) and Aloka Model SSD-5500 (3.75 MHz) ultrasound systems. Two thousand thirty-six laparoscopic cholecystectomy procedures were carried out at this institution from 1990 through 2001. During this period, we encountered seven cases of intra-abdominal abscess. Three of these cases were symptomatic, but abscess, granulation, or both, were found incidentally by ultrasonography in the other four patients during routine annual health examinations. Laparotomy and open drainage of pus and gallstones from the intra-abdominal abscess were necessary in five cases. Ultrasonography revealed a mass in six of the seven patients. The abscesses were located in either the right subphrenic or subhepatic space on the surface of the liver and were sometimes difficult to distinguish from liver tumors. Ultrasound showed the abscesses as oval, low-echoic, solid masses with posterior enhancement. They ranged from 20 to 58 mm in diameter, had clear margins and highly echoic peripheral rims, and showed lateral shadowing. The lesions also contained several highly echoic spots with acoustic shadows that were thought to be the spilled stones. We conclude that visceral abscess should be considered after laparoscopic cholecystectomy, and that careful observation using ultrasonography is required, especially when the gallbladder is perforated and bile and stones have spilled out.