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Semin intervent Radiol 2012; 29(04): 325-336
DOI: 10.1055/s-0032-1330068
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Abscess Drainage

Hearns W. Charles
1   Section of Vascular & Interventional Radiology, NYU Langone Medical Center, New York, New York
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Publication Date:
11 December 2012 (online)

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An abscess is a localized collection of purulent fluid that can have a significant impact on the care and clinical outcome of a patient. It is at times a relatively benign event, potentially treatable with antibiotic medication alone. However, not uncommonly, abscess formation can be a life-altering event if it leads to sepsis, a spectrum of severe systemic illness resulting from hematogenous spread of infection and an important cause of morbidity and mortality.[1] Sepsis is among the 10 leading causes of death in the United States[2] and results in a rapid cascade of potential life-threatening events that can include bacteremia, cardiac decompensation, acute respiratory distress syndrome (ARDS), hemodynamic compromise, and organ failure. Sepsis typically results in prolonged hospitalization or even death. In addition, treatment of sepsis is a major component of health care expenditure. The total annual cost for the hospitalization of patients with severe sepsis in the United States has been estimated at $16.7 billion, and it is postulated that this figure has probably risen since these data were published in 2006.[3]

Historically, intra-abdominal abscesses were treated with operative drainage that was associated with significant morbidity and mortality.[4] In the last 2 decades, advances in image-guided percutaneous drainage have provided a safe and effective alternative to operative debridement.[5] Presently, most would consider image-guided percutaneous abscess drainage (IGPAD) as the treatment of choice because it offers a relatively simple, minimally invasive option with the goal of averting the development of sepsis, reducing length of hospital stay (LOS), and reducing the cost of treatment. Indeed in some cases, IGPAD can be performed successfully on an outpatient basis.[6] Radiologists possess knowledge of anatomy, familiarity with most types of drainage procedures, and expertise in procedural tools and techniques, and therefore they are well suited to perform IGPAD with a high rate of technical and clinical success. For example, computed tomography (CT)-guided abscess drainage has been shown to provide definitive treatment for 70 to 90% of abdominal abscesses.[6] IGPAD can be a relatively simple and short procedure; however, as with any seemingly simple procedure it can be made complicated by improper techniques. This article reviews basic techniques and aims to offer 11 helpful points to simplify the technique, minimize procedure time, and maximize technical and clinical success rates.

Preprocedural evaluation includes the attainment of informed consent from the patient or the designated health care proxy, and preprocedural planning includes a thorough review of appropriate imaging studies and appropriate laboratory parameters. Although IGPAD is considered to be associated with only a moderate risk of bleeding,[7] serum coagulation parameters should be adequate to proceed with the procedure. In my practice, platelet count should be at least 50,000/µL and international normalized ratio (INR) should be <1.5. In addition, a serum hemoglobin level of at least 9.0 g/dL is optimal, particularly in high-risk cases. Aspirin need not be held but thienopyridines such as clopidogrel should ideally be withheld for 5 days prior to the procedure. Withholding of low molecular weight heparin may depend on the particular agent and its associated half-life. I recommend withholding these agents for two to four half-lives prior to the procedure, although exceptions may be made in particularly urgent cases. If time permits, coagulopathy and severe thrombocytopenia can be corrected with transfusions using fresh-frozen plasma and platelets, respectively, as well as other factors.

Ultrasound (US) and CT are the most commonly used imaging modalities to guide IGPAD, and fluoroscopy is often also used to guide serial dilatation and catheter placement following successful needle access.

The techniques of IGPAD are well known. Either the Seldinger or the trocar technique is used, depending on the size and location of the abnormality. With the trocar technique, the collection is initially accessed using a small gauge needle and contents are aspirated to verify needle placement. Then, parallel to this needle, a coaxial combination of a catheter, stiffening cannula, and sharp stylet is advanced directly into the collection. With the Seldinger technique, initial access to the cavity is gained using a small 21- or 22-gauge needle, followed by 0.018-in wire conversion to 0.035- or 0.038-in wire with the use of a Cope (Cook Medical, Bloomington, IN), Neff (Cook), or AccuStick (Boston Scientific, Natick, MA) coaxial catheter introduction system. Seldinger technique is often used for small deep, high-risk, and difficult-to-access collections, and the trocar technique is often used for large and superficial collections. Anecdotal evidence shows there is more patient pain associated with the trocar technique, and direct, nontarget catheter placement with a large-bore catheter using the trocar technique may result in greater morbidity than initial nontarget access with a skinny needle using the Seldinger technique. However, trocar technique offers the advantages of speed and avoidance of extra-cavitary leakage of abscess contents associated with serial access tract dilatation.

Rarely, the viscosity of the cavity content may prevent successful fluid aspiration. Aborting the placement of a drainage catheter may be premature in such cases, with the operator believing that the cavity does not contain any fluid but it is instead an “undrainable” phlegmon, hematoma, or other pathology. An alternative and useful test is to perform the wire test. Successful passage of the initial guidewire, especially if it assumes the shape of the cavity, implies that the content of the cavity is at least partly fluid. In most such instances, fluid can be successfully aspirated upon the introduction of the drainage catheter or a dilator with multiple side holes such as a biliary type catheter and a Yueh needle (Cook Medical, Bloomington, IN), respectively. In other cases, advancement of a catheter into an apparently undrainable collection can be followed by instillation of tissue plasminogen activator (TPA) fibrinolytic therapy to facilitate complete drainage.