Special considerations in cyst and collection drainage

Cyst drainage and prevention of dissemination

When working with parenchymal organ cysts (e.g., the spleen), the access trajectory must pass through an area of unaffected, normal tissue. Due to the high risk of delayed hemorrhage after drainage catheter placement, patients must be admitted overnight for observation.

When choosing the instrumental access technique, preference is given to the tandem-trocar technique (tandem-trochar technique) rather than the classic Seldinger technique. This is crucially important for two reasons:

• It avoids additional dilation of the tract, which is necessary when using a guidewire.
• It minimizes the risk of contaminating the pleural or abdominal cavity with cyst contents.

This choice is especially critical in the treatment of hydatid disease (hydatid disease), where accidental fluid leakage into the abdominal cavity leads to parasite dissemination (seeding).

For ablation of the inner cyst lining, the following algorithm is used:

1. Administration of contrast media to confirm integrity (absence of leakage).
2. Replacement of the aspirated fluid volume with 95% ethanol.
3. Clamping the catheter for 20 minutes.
4. Aspirating the alcohol (the cycle can be repeated if necessary).

Subphrenic collections

Subphrenic collections (subphrenic collections) require careful trajectory planning. The lower anterior approach is considered optimal. It avoids pleural puncture and reduces the likelihood of infection spreading into the thoracic cavity. Unlike cystic lesions, the Seldinger technique is used here more frequently.

Navigation is traditionally performed under ultrasound guidance. However, if the collection contains gas or has a complex configuration, CT guidance may be required.

Complications and their management:

• If pleural puncture was technically unavoidable, the patient is scheduled for serial chest X-ray monitoring.
• If increasing pleural effusion is detected, urgent chest tube insertion is indicated to prevent the development of empyema (empyema).

The contents of right- and left-sided subphrenic collections must be sent for biochemical analysis. Determining bilirubin and amylase levels helps identify the fluid source (biliary tract or pancreas) and plan further specialized drainage.

Abdominal cavity and complex approaches

Abdominal paracentesis (paracentesis) is one of the most routine image-guided procedures. Standard preparation and local anesthesia are sufficient for fluid evacuation, and small-bore catheters (7–8 French) are typically used as instruments. The most common causes of massive ascites include portal hypertension, liver cirrhosis, and various malignancies.

When draining complex, walled-off collections (e.g., walled-off pancreatic necrosis deforming the lesser sac), imaging guidance makes it possible to choose a safe trajectory. In such cases, a special angled approach (angled approach) under ultrasound guidance is often used, allowing a larger drain (e.g., 10 Fr) to be placed while bypassing the stomach, avoiding unwanted transgastric passage. A properly placed drain leads to the complete resolution of the collection on follow-up CT scans.

Class and exam questions

What else to study on this topic

• Comparative characteristics of the Seldinger technique and the tandem-trocar technique
• US and CT anatomy of the lesser sac and subphrenic spaces
• Imaging findings and stages of development of walled-off pancreatic necrosis
• Prevention and treatment of pleural empyema in iatrogenic injuries
• Specifics of draining hydatid cysts of the liver and spleen

Other topics in the "Interventional radiology" section

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