Interventional radiology Abscess drainage
Drainage of abdominal and retroperitoneal abscesses
Since the introduction of ultrasound-guided abscess drainage in 1974 by Holm et al. and CT -guided drainage in 1976 by Haaga et al. abdominal abscess drainage has become an established radiological method. With a significantly lower mortality rate compared to surgical drainage 80-85 % of abscesses can be treated exclusively by percutaneous catheter drainage. Whether ultrasound or CT-guidance for catheter insertion is selected depends mainly on the expertise of the performing radiologist with each modality. In addition however, overlying structures such as bone (ribs) or gas-filled bowel may limit the use of ultrasonic guidance. Depending on the size and anatomic location (i.e. the route of access), a Trocar or Seldinger technique is used. Most commonly catheters of 8-12F are sufficient, however larger catheters may be necessary to drain purulent and necrotic material (Fig. 14). The aspirated fluid or pus is always sent for Gram-stain and culture. Exact catheter placement may be controlled by repeated CT or careful injection of contrast material under fluoroscopy. Sterile fluid collections and non-infected cysts such as pancreatic pseudocysts are evacuated through the needle without leaving
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Figure 14.
Patient with retroperitoneal abscess and fever following endoscopic papillotomy for biliary calculi.
A + B) CT at two different levels in lower abdomen shows fluid collection containing air in right retroperitoneum (arrows).
C + D) Two days after CT guided drainage with three Pigtail-catheters the fluid collection has markedly diminished. The temperatures have subsided. Arrows mark two of the draining catheters.
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Figure 15.
Patient with hydronephrosis and fever secondary to metastatic obstruction of right ureter.
A) Percutaneous antegrade pyelogram with Chiba-needle shows dilated renal pelvis with obstruction of the right ureter at the level of L4.
B) A Pigtail catheter has been inserted for drainage.
C) After passing the ureteral obstruction with a guidewire and balloon dilation of the
ureter a double Pigtail catheter has been placed for permanent internal drainage.
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drainage catheters in place.
Percutaneous drainage of thoracic fluid collections
In contrast to abdominal abscess drainage, percutaneous treatment of thoracic fluid collections has received less attention with the exception of drainage of pleural and pericardial effusions. Empyema, lung abscess and mediastinal fluid collections are successfully treated with catheter drainage if they do not respond well to antibiotic therapy. The basic techniques for catheter placement are again the Trocar or Seidinger method with ultrasound or CT guidance. The main potential complications are pneumothorax or bleeding.
Christoph Zollikofer