Main requirements for the feeding pedicle
To prevent necrosis of the transposed skin and subcutaneous tissue fragment, several surgical rules must be strictly followed when forming the feeding pedicle:
- It must have sufficient width to guarantee adequate arterial inflow and venous outflow.
- Tight bandaging or any compression of the pedicle with dressings is strictly prohibited.
- During the tissue transposition to the defect, it is important to ensure that the pedicle does not twist around its longitudinal axis, as this threatens vascular occlusion.
Local (regional) plasty
This type of plasty involves using tissues directly adjacent to the wound. The defect is closed by shifting, rotating, or stretching them.
The following technical approaches exist:
- Mobilization of edges: the wound edges are undermined from the underlying tissues and then sutured without tension.
- Relieving incisions: additional incisions are made a few centimeters away from the wound. This relieves tension and allows the primary edges to be approximated.
- Z-plasty: used to eliminate severe scar deformities. The scar is excised, after which triangular flaps are incised and transposed (interchanged).
- Rotational flap: a tongue-shaped fragment of healthy skin is incised next to the defect and rotated onto the wound. A classic example is the Indian method of nose reconstruction using a forehead flap.
Flap plasty from distant areas
If there are no suitable healthy tissues near the wound, transplantation from other anatomical zones is resorted to.
Italian method (direct transplantation) The essence lies in the single-stage transposition of a flap from a nearby area. A mandatory condition is the ability to approximate and fix the donor site and the defect area. For example, closing a wound on the nose with an arm flap (with the arm fixed to the head until engraftment), or transplantation from the shin to the shin.
Bridge plasty Proposed by N.V. Sklifosovsky for closing wounds on the hand, fingers, or forearm.
- Two parallel incisions are made on the abdomen or forearm.
- The skin between them is undermined, forming a peculiar "bridge".
- The damaged limb is placed under this bridge, and the flap edges are sutured to the wound.
- In 10–15 days, after the restoration of blood supply from the recipient bed, the pedicles are severed.
Migrating flap: Filatov tube
If the defect is far from the donor site (most often the anterior abdominal wall) and direct apposition is impossible, migrating flap plasty is used. Tissues are transposed to the wound gradually, in stages ("walking" across the body).
Formation technique:
- Two parallel incisions are made down to the fascia.
- The edges of the resulting skin strip are sutured together into a tube with the skin facing outward (resembling a suitcase handle). It is important to observe the proportion: the length of the tube must not exceed its width by more than 3 times.
- The wound under the tube is sutured.
Migration stages:
- Maturation: about 10–14 days, until a reliable vascular network is formed inside the tube.
- Transplantation to a "carrier": after 4 weeks, one of the pedicles is severed from the abdomen and sutured to the forearm or hand.
- Transfer to the defect: after another 10–14 days, the second pedicle is severed from the abdomen and fixed directly in the affected area (e.g., on the face).
The round migrating tube is used to close extensive wounds, trophic ulcers, stumps, reconstruct the nose, lips, palate, and is also applied in esophageal, tracheal, and vaginal surgery.
Briefly: answers to topical questions
What tissue layers are included in the formed Filatov tube?
The formed Filatov tube includes the epidermis, dermis, and subcutaneous adipose tissue. When excising the musculocutaneous flap, incisions are made down to the muscular fascia. An important surgical rule is that the thickness of the captured adipose tissue must be strictly uniform throughout the entire excised tube. After mobilization, the edges of the skin strip are sutured together, forming a tube with the skin surface facing outward.
How is the viability test (training) of the Filatov tube performed before severing the feeding pedicle?
Training of the Filatov tube consists of applying a thin tourniquet or clamp to the pedicle of the tube to be severed. The procedure aims to gradually enhance blood circulation. On the first day, compression is applied for 3–5 minutes, then the time is increased daily by 5–10 minutes. The criterion of readiness is the absence of cooling, edema, or cyanosis of the tube when tightening the pedicle for 1 hour. However, in modern practice, the training of tube pedicles should be abandoned. It has been proven that trauma from tourniquets causes deformation and cicatricial changes in the feeding vessels, and the tissue respiration level of trained tubes noticeably lags behind the norm.
What are the contraindications for pedicle skin grafting?
The literature describes only specific contraindications for the use of particular pedicle skin grafting techniques.
- Local plasty — the use of local tissues (incisions, transposed flaps) is contraindicated in extensive defects due to the high risk of necrosis, as sutures are placed on tissues with reduced viability.
- Filatov tube — an absolute contraindication when choosing a donor site is the inclusion of breast tissue in the formed tube.
Class and exam questions
What is the difference between the Indian and Italian methods?
The Indian method is local plastic surgery (the flap is taken from the forehead and rotated to the nose). The Italian method is direct transplantation from a distant site (a flap from the arm, requiring rigid fixation of the hand to the head).
What is the purpose of Z-plasty?
It is used in the treatment of severe scars. Interchanging triangular flaps allows lengthening the scar, changing its direction, and relieving tissue tension.
What are the engraftment times for a pedicle flap?
As in the Italian method and during the migration stages of the Filatov tube, the development of new blood vessels and engraftment take an average of 10–15 days.
What else to study on this topic
- V-Y plasty technique
- Features of immobilization in the Italian method
- Application of the Filatov tube in maxillofacial surgery
- Prevention of feeding pedicle necrosis
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