Surgical steps for port placement
The implantation completion procedure begins with effective anesthesia. For local anesthesia, the insertion site is infiltrated with 20 ml of 1% lidocaine (lidocaine) solution with added adrenaline (adrenaline) in a 1:100,000 ratio.
An incision 4 to 5 centimeters long is made along the line of the axillary fold; for aesthetic reasons, it can be shifted somewhat medially.
Creation of the subcutaneous pocket (bed) Using haemostatic forceps (haemostatic forceps), a subdural superomedial pocket is created by blunt dissection. The ideal size of the bed is determined by a simple test: the rounded rings of the working forceps branches should pass freely into the created cavity.
If the patient has prominent breast tissue, the pocket is created more anteriorly, placing it directly over the clavipectoral fascia (clavipectoral fascia). This offers two major advantages:
- It provides reliable posterior support, which is critical for subsequent punctures of the port with a Huber needle (Huber needle).
- It significantly reduces the risk of spontaneous device rotation in the tissues (when the silicone septum is no longer facing the skin).
Next, the port is connected to the venous catheter. The catheter itself is passed through a specially created subcutaneous tunnel to the neck incision. Final positioning is performed strictly under fluoroscopy (fluoroscopy): the tip must lie precisely at the atriocaval junction (atriocaval junction). A peel-away sheath (peel-away sheath) is used for insertion.
Wound closure and finalization
Wound closure after port placement is performed in several stages to ensure reliability and cosmetic effect:
- 2–3 deep dermal stitches are placed using 2-0 Vicryl suture.
- The skin is closed with a continuous subcuticular stitch (4-0 Monocryl suture), which is secured with an Aberdeen knot (Aberdeen knot).
- As an alternative or supplement to the subcuticular suture, a special dermal glue (dermal glue) can be used. It creates an instantaneous waterproof layer and serves as an additional physical barrier against infection.
The final step includes mandatory fluoroscopy to document the correct catheter position. The internal port system is locked with a heparin (heparin) solution. If the patient is to start chemotherapy within the first few days after surgery, the locked Huber needle may be left in situ (in situ).
Tunneled hemodialysis catheters
In renal failure, surgical arteriovenous fistulas (AVFs, arteriovenous fistulas) or synthetic vascular grafts (grafts) remain the priority vascular access.
Special devices and grafts When a patient has bilateral central venous stenosis that precludes the use of peripheral native veins, yet maintains good cardiac output and a healthy brachial artery, a HeRO graft (Haemodialysis Reliable Outflow) is used. This hybrid device is placed jointly by a surgeon and an interventional radiologist:
- A nitinol-reinforced (nitinol) silicone catheter is inserted through the internal jugular vein and tunneled to the deltopectoral groove (deltopectoral groove).
- A PTFE graft (PTFE graft) is anastomosed to the brachial artery and connected to the catheter using a titanium connector.
The main advantage of the HeRO system is that it is ready for cannulation immediately after implantation, without a maturation period.
Endovascular fistulas Technologies such as the everlinQ endoAVF system allow fistula creation without open surgery. Introducers are inserted retrogradely into the brachial artery and vein. Magnetic catheters align the vessels parallel to each other, after which a radiofrequency electrode (radiofrequency electrode) creates the anastomosis. However, this method requires embolisation (embolisation) of distal brachial veins to redirect blood flow into the superficial network.
Specifics of dialysis lines
Tunneled dialysis catheters are used only when other access options are exhausted or while a surgical fistula is maturing.
Important technical differences:
- The tip is placed significantly deeper, in the right atrium (right atrium), to provide the high flow rate required for dialysis.
- Catheter length is fixed. For example, left internal jugular vein access requires a length of 32 cm (rather than 28 cm) due to the longer anatomical pathway to the superior vena cava.
- Tesio catheters (Tesio lines): These consist of two independent catheters. They are placed through two separate punctures, with a distance of more than 1 cm between them. This prevents the guttering phenomenon (guttering phenomenon) and bleeding. Separate lines have greater tip mobility, which effectively prevents fibrin sheath (fibrin sheath) formation and thrombosis (thrombus).
Non-standard access If the thoracic central veins are occluded, alternative pathways are used. Femoral veins (femoral veins) can be utilized, although this sharply increases the risk of catheter-related bloodstream infections. For direct access to the inferior vena cava (IVC), hepatic (hepatic) or lumbar (lumbar) veins are used. Translumbar direct puncture of the inferior vena cava is the method of choice in severe thoracic vein occlusion: the procedure takes longer but is characterized by high clinical success.
Briefly: answers to topical questions
What complications can arise from prolonged placement of a tunneled catheter in the femoral vein?
When using the femoral veins (femoral veins) for tunneled catheter placement, the main complication is an increased risk of catheter-related infection. This access is considered non-standard and is used only when standard access sites are exhausted due to scarring or thrombosis. Clinical guidelines advise avoiding the femoral vein for any hemodialysis catheter localization to minimize overall risks of catheter-related complications.
What is the exact mechanism of anastomosis formation using the everlinQ endoAVF system?
The mechanism of anastomosis formation using the everlinQ endoAVF system is based on magnetized catheters and a radiofrequency electrode. The procedure includes the following steps:
- Introduction of introducers — retrograde placement in the brachial artery and adjacent brachial vein.
- Vessel alignment — magnetized catheters position the artery and vein parallel to each other.
- Fistula creation — a radiofrequency electrode (radiofrequency electrode) creates an anastomosis between the vessels.
- Embolisation (embolisation) — closure of distal sections of the brachial vein to redirect blood outflow into the superficial venous system.
Class and exam questions
Why is the port pocket placed superficial to the clavipectoral fascia in patients with prominent breast tissue?
This provides rigid posterior support necessary for the safe insertion of the Huber needle and prevents accidental flipping of the port with the silicone septum facing downward.
What is the advantage of Tesio catheters over double-lumen dialysis catheters?
Tesio catheters consist of two separate tubes, which increases their mobility in the bloodstream. This significantly reduces the risk of fibrin sheath formation and subsequent thrombosis.
Which approaches are used in total occlusion of central chest veins?
In such cases, translumbar direct puncture of the inferior vena cava, transhepatic access, or catheter placement in the femoral veins is used (despite the high risk of infection).
What else to study on this topic
- Technique of placing the Aberdeen knot in subcuticular suturing
- Heparin lock protocols for port systems
- Venography and balloon venoplasty before dialysis catheter placement
- KDOQI clinical practice guidelines for vascular access selection
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