Percutaneous Abscess Drainage Technique

Updated: Apr 28, 2016
  • Author: Evan J Samett, MD; Chief Editor: Kyung J Cho, MD, FACR, FSIR  more...
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Technique

Percutaneous Drainage of Abscess

PAD technique

The PAD technique depends on case specifics and personal preference. Consider location of the fluid collection and the likelihood that it is infected as well as the patient's overall condition.

The optimum access route is determined by the following:

  • Shortest pathway
  • Easiest angulation or localization
  • Avoidance of intervening or adjacent structures - Bowel (peritonitis risk), vital organs (bleeding risk, especially spleen), and sterile pleural effusions (secondary empyema risk)
  • Most convenient catheter location for patient
  • For a solid organ abscess (eg, liver), access path should traverse a small amount of normal organ to reduce the risk of peritoneal spillage and bleeding

Bowel transgression is of concern, particularly when it involves the colon. One may traverse bowel when the alternatives have a higher risk-benefit ratio. Bowel transgression is generally tolerated when multiple needle punctures are avoided, and the catheter is left in for at least 2 weeks to create a mature tract. Referring/surgical service should be aware of the increased PAD risk in these situations. One should avoid aspiration of "low-probability" collections through the colon.

PAD is performed by using standard aseptic technique and local lidocaine anesthesia. Begin with a diagnostic aspiration, followed by catheter placement if fluid is purulent. Alternatively, a trocar technique may be used. Simple abscesses smaller than 5 cm in diameter may be treated with aspiration (and lavage) alone.

Localization techniques

The localization technique is influenced by individual and institutional preference. Any modality may be used to assist needle placement. Computed tomography (CT) fluoroscopy is increasingly available and facilitates "one-stop-shopping," allowing diagnostic CT and PAD to be performed readily in a single setting. If CT fluoroscopy is not available, patient assessment may be performed with CT, and the PAD procedure may be performed with US localization. Conventional fluoroscopy can be used as an adjunct to US. [15] US guidance allows real-time imaging and does not involve radiation exposure. [16, 17]

Large abscesses are amenable to "point-and-shoot" US localization. Manipulate the transducer to determine the puncture site, angle, depth, and margin for error. Mark the site by indenting the skin with the hub end of a needle. Entry is memorized, a one-blade-diameter skin incision is made with a No 11 scalpel, and the needle is placed without further imaging. Real-time US may be used for small, deep, or otherwise difficult access. A HiLiter needle (Inrad) may assist real-time guidance. In addition, US guidance hardware and software may make a difficult access much easier for those operators who are less experienced at free-hand sonographic guidance.

Use an 18-gauge, 15-cm trocar needle (DTN-18-15.0, Cook) with an 8.5-French general-purpose locking pigtail catheter (ULT8.5-38-25-P-6S-CLM-RH, Cook). A 21- to 22-gauge needle or a 12- to 14-French drainage catheter are not usually required for safety, efficacy, or fluid dynamics. When indicated, use the Accustick (Boston Scientific) needle or Neff Percutaneous Access set (NPAS-100-RB-NT, Cook). Larger-diameter drainage catheters are available from various vendors. Exceptions include viscous fluids and collections of necrotic tissue such as pancreatic infections or some empyemas.

Pearls

Maintaining guide-wire access

It is critical to never lose guide-wire access during any portion of a drainage procedure. When access is lost, reentry may be difficult because of spontaneous decompression of the abscess or difficulties in imaging from disruption of the region. An advantage of the Accustick system is that it retains the 0.018-in. wire as the 0.038-in. wire is passed. If the larger wire becomes dislodged, then the smaller wire can be used for repeat access.

The author uses Teflon dilators with a Coons modification in which the tip tapers over a 5-cm length rather than the standard 1 cm. The Coons modification allows the author to use only even-size French dilators. The author always overdilates to the next even dilator size to ease catheter passage.

When encountering difficulty passing the dilator or catheter, check the skin incision first. There may be a remaining strand of subcutaneous connective tissue, or the incision may be too small. The easiest way to assess this is to gently pull back on the dilator or catheter (without losing guide-wire access). If the skin tents up as the catheter is withdrawn, enlarge the incision and reattempt passage. Hydrophilic coated dilators are now available (Cook) that greatly ease dilator passage. They use similar technology to that seen in the popular hydrophilic guide wires and are only slippery when wet.

Dealing with resistance to dilator or catheter

When there is resistance to passing the dilator or catheter, the assembly may kink under the skin. This is best determined with fluoroscopy. When it occurs, gently withdraw the wire and catheter as a unit to undo the kink, then try to readvance slowly. Have an assistant hold the guide wire straight to prevent buckling or accidental withdrawal. Buttress the tissues with a free hand, hold the catheter close to the skin, and advance the catheter or dilator in short firm strokes. This increases the radius of curvature (reduces buckling) and increases the effective rigidity of the unit.

If this fails, either the catheter/dilator or the guide wire must be exchanged. If there is sufficient catheter or dilator in the abscess, then the wire may be exchanged for a more rigid or nitinol variety. If not, the dilator or catheter may be exchanged for a hydrophilic 5-French dilator, whereupon a stiffer wire may be exchanged. Occasionally, either the tract must be balloon-dilated or an alternate access route chosen. These issues occur more frequently in scarred areas (eg, in patients who have had multiple nephrostomy procedures).

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Postprocedural Care

Management of the patient with an abscess drainage catheter is best performed in a cooperative fashion with referring and surgical services. The quality and quantity of drainage is monitored along with signs of patient recovery. Clinical follow-up care may be augmented by CT, US, fluoroscopy, and plain-film contrast studies if the infection is not resolving. Additional catheter manipulation or placement is based on these results.

Simple abscess treatment usually is complete within 1-2 weeks. A complex abscess or enteric fistula may require weeks to months. Over the course of therapy, catheters may have to be revised, replaced, or repositioned. There are different approaches to post-PAD catheter management. Some prefer to remove the catheter as soon as drainage diminishes below 10 mL/shift. The author prefers to keep the catheter in until the cavity begins to close. Depending on the case, treatment is complete within a matter of days to weeks. Patients usually receive concurrent antibiotic therapy.

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Complications

Significant complications of PAD are rare. One significant complication at the author's institution occurred in a patient with a pancreatic region abscess when the catheter entered the duodenum. Although the patient did well clinically, the high volume of gastric juice drainage prompted surgery. Given the location of the patient's original abscess, this complication was not unexpected. [16]

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