Access to retroperitoneal collections

Access options in clinical cases

When draining fluid collections in the retroperitoneal space and pelvis, the choice of trajectory depends on the location of the lesion. In addition to classic transabdominal routes (including transmural gastric puncture), specialized approaches are actively employed.

Transrectal approach Effective for lesions located deep in the true pelvis. A characteristic clinical case: a 37-year-old female patient with a rectal perforation resulting from radiation therapy for cervical carcinoma. Sagittal contrast-enhanced CT demonstrates a collection in the pouch of Douglas (pouch of Douglas) with distinct peripheral contrast enhancement. The procedure is performed under fluoroscopic guidance (fluoroscopy): an 8-F drainage catheter is introduced into the cavity and coiled. Dynamic sagittal CT in such cases demonstrates virtually complete resolution of the fluid collection.

Transgluteal approach Performed through the gluteus muscle under computed tomography guidance. A notable case is a 33-year-old male with a pelvic mass that developed after partial colectomy for colorectal carcinoma. Axial CT slices visualize a pelvic collection with characteristic peripheral contrast enhancement. Puncture is performed transgluteally, after which a rigid straight Amplatz wire (Amplatz wire) is placed into the cavity using the classic Seldinger technique (Seldinger technique).

Management of paediatric patients

Drainage in pediatric practice requires a fundamentally different approach compared to adult patients. The most common indications are collections associated with acute appendicitis, inflammatory bowel disease (IBD), or postoperative complications.

• Equipment and conditions: All vital sign monitoring and resuscitation equipment must be strictly adapted to the child's age and weight. It is extremely important to apply measures to minimize patient body heat loss. The procedure is performed under sedation, which must be administered by an anesthesiologist.
• Image guidance: To minimize radiation exposure, ultrasound (ultrasound) is preferred as the primary guidance method. Once high-quality planning images are obtained, higher-noise images may be used for subsequent catheter position monitoring (to reduce radiation dose).
• Monitoring: In the postoperative period, the use of CT should be kept to an absolute minimum or completely eliminated. Evaluation of drainage efficacy is based exclusively on the patient's clinical response, ultrasound findings, and the volume of output through the drainage tube.
• Role in appendicitis: Image-guided catheter drainage has proven to be safe and highly effective in treating appendicitis complicated by abscess formation. The procedure reliably reduces the complication rate. Furthermore, successful percutaneous drainage of a perforated appendiceal abscess often avoids the need for an interval appendectomy (interval appendectomy).

Complications prevention and catheter removal

Any invasive intervention carries the risk of complications (complications). Even with perfect technical execution, the patient may experience discomfort, and a scar will inevitably form at the percutaneous insertion site.

Proper communication is essential to minimize risks. From the outset, the physician must clearly explain to the treatment team and the patient what realistic outcomes to expect from the drainage to prevent any misunderstandings.

An interventional radiologist's role goes beyond performing the procedure in the operating room. Their participation in regular ward rounds is critically important for proper catheter care, continuous staff training, timely information sharing with attending surgeons, and the earliest possible detection of any developing complications.

Difficulties in catheter removal The main rule is to make every effort to remove the drainage tube as soon as possible. However, some pathological collections respond extremely slowly to ongoing therapy, necessitating prolonged drainage. Factors hindering prompt removal:

1. Presence of a malignant tumor.
2. Formation of a pathological fistula (fistula).
3. Development of loculations (loculations) within the collection.

Management of loculations If an abscess cavity is partitioned by internal septations (loculated), adequate fluid drainage ceases. In such situations, a set of measures is applied: the drain is replaced with a larger-diameter tube, the catheter is repositioned within the cavity, or special drugs are instilled. The only effective agent for the chemical lysis of such septations is tissue plasminogen activator (tPA). Using regular saline, aminocaproic acid, or heparin in these situations is ineffective.

Class and exam questions

What else to study on this topic

• Features and instrumentation of the Seldinger technique (Amplatz wire)
• Specifics of sedation and hypothermia prevention in pediatric interventional radiology
• Mechanism of action of tissue plasminogen activator (tPA) in loculated abscesses
• Pelvic imaging anatomy in transrectal and transgluteal approaches

Other topics in the "Interventional radiology" section

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