Indications and Diagnostics
Percutaneous drainage (percutaneous drainage) is used to evacuate pus, relieve symptoms, and obtain fluid for laboratory analysis. Infected cavities do not take up antibiotics well, so without mechanical removal of the substrate, treatment is only effective for extremely small collections (up to 3 cm). In other cases, drainage is required, supplemented by antibiotic prophylaxis to prevent secondary infection.
In addition to abscesses, the method is indicated for symptomatic sterile collections: urinomas, seromas, hematomas, or obstructive hydronephrosis. Drainage monotherapy is especially successful in treating postoperative collections (e.g., in anastomotic leakage) when re-operation is difficult due to adhesions.
The collected fluid is sent for culture, Gram staining, and cell counts. Specific markers help determine the source:
- Amylase — collection of pancreatic origin.
- Bilirubin — biliary.
- Creatinine — urinary.
- Lymphocytes — lymphatic.
Contraindications and Surgical Tactics
Today, the only absolute contraindication to the procedure is the absence of a safe percutaneous access route due to obstructing internal organs or vessels. Patient non-compliance or anxiety is easily managed with general anesthesia.
Relative contraindications include:
- Uncorrectable coagulopathy.
- Hemodynamic instability.
- Uninfected (sterile) collections without symptoms.
- Tumor abscesses (catheters placed in them often remain indefinitely).
- Transpleural access procedures due to the risk of empyema.
- Echinococcal cysts (although modern data suggest they can be safely drained without anaphylaxis).
The presence of gas within the collection itself is not a contraindication — it is a typical consequence of local GI microperforation (in appendicitis or diverticulitis). However, percutaneous drainage is replaced by open surgery if the patient is diagnosed with generalized peritonitis, has a massive free gas accumulation in the abdominal cavity, or if the abscess has not yet matured.
Safe Trajectory Rules and Organ Traversal
Access planning requires careful review of CT images. To create a safe window to difficult-to-reach areas, hydrodissection (hydrodisplacement) is used — injecting fluid to displace adjacent structures — or the gantry tilt angle of the CT scanner is adjusted.
When advancing the needle and catheter, it is strictly prohibited to traverse:
- Blood vessels;
- Spleen and pancreas;
- Gallbladder and urinary bladder;
- Esophagus, small and large intestine;
- Uterus and ovaries.
The only exception is the liver. Provided that coagulation parameters are normal, traversal through a minimal segment of hepatic parenchyma is permitted. The main condition is to strictly avoid portal vessels and the gallbladder. Furthermore, all side holes of the catheter must be located inside the abscess cavity to prevent pus leakage along the tract into the liver tissue. For collections deep in the lesser pelvis, obscured by bones and bowel loops, a transcompartmental approach (transrectal or transvaginal) is often chosen.
Preparation, Risks, and Potential Complications
Coagulopathy must be corrected prior to the intervention. For high-risk procedures, correction is mandatory if the platelet count drops below 50,000/μL combined with an INR > 1.5, or if the partial thromboplastin time (PTT) is 1.5 times the upper limit of normal.
Displacement and accidental dislodgement of the catheter are frequent occurrences. Patients must be instructed on the risks of pulling on the tube. If the catheter falls out but no more than 24 hours have passed, it can usually be reinserted ("saved") through the still-open tract.
Bleeding after placement is not uncommon. The discharge of altered blood from the postoperative wound is usually not threatening. However, if vascular injury is suspected (e.g., formation of an arterial pseudoaneurysm), the catheter is immediately exchanged over a guidewire for a larger-bore tube to provide local tamponade, followed by embolization.
With chest tube drainage, complications are rare but may include pneumothorax (requiring aspiration), intercostal artery injury, or erroneous intraparenchymal placement of the pleural tube.
To remember which organs MUST NOT be crossed during puncture, keep in mind: avoid hollow organs (risk of peritonitis and fistulas), richly vascularized parenchymal organs (spleen, pancreas), and outflow tracts (gallbladder and urinary bladder). Traversing the liver is acceptable, but minimally and with caution.
Class and exam questions
Is the presence of gas in an abscess a contraindication to percutaneous drainage?
No. Localized gas within a closed collection is a frequent consequence of GI perforation (e.g., in diverticulitis) and does not preclude the procedure. Surgery is only required in the presence of a large volume of free intraperitoneal gas.
What to do in case of massive bleeding from the drainage tract?
It is recommended to remove the current catheter over a guidewire and temporarily place a larger-bore drainage tube for tamponade. This stabilizes the situation prior to definitive treatment, such as transarterial embolization or surgery.
Why are deep pelvic abscesses difficult to drain percutaneously?
In the lesser pelvis, bony structures, nerves, major vessels, bowel loops, and the urinary bladder often lie in the needle's path. Therefore, transrectal or transvaginal catheter placement is frequently used to ensure safe access.
What else to study on this topic
- Seldinger Technique for Drainage Catheter Placement
- Hydrodissection Method for Organ Displacement
- Specifics of Transgastric Drainage of Pancreatic Collections
- Management Tactics for Patients with Infected Tumors and Fistulas
- Anticoagulation Management Before High-Risk Procedures
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- Complete Guide on "Image-Guided Drainage Techniques" and 2,199 Other Subject Pages
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