Caudal superficial epigastric flap (2023)

The caudal superficial epigastric (CSE) flap is a very versatile skin flap with an axial pattern that can be used to cover large open wounds.Figure 1) in him:

• Ipsilateral or contralateral mid-to-caudal trunk
• Perineum
• Later limbs (to some extent).

In dogs with larger body length to limb length ratios (such as basset hounds) and cats, this flap can extend to cover wounds as distal as the metatarsal.

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This extensive swath of skin transfer is due to the long and robust CSE artery, which branches from the external pudendal artery in the caudal part of the inguinal canal; then continues cranially just below the mammary glands along the mammary row (Figure 2).

When the flap is created, most of the skin in the pectoral chain, once the cranial, medial and lateral aspects of the flap have been released, can be lifted away from the abdominal fascia and effectively transferred to distant skin defects. The donor skin defect can then be closed routinely, similar to closure after a unilateral mastectomy.

Indications

Due to the flap's abundant blood supply and thick subcutaneous tissue padding, the flap can be used to cover:

• Deep wounds without granulation bed
• Wounds with exposed bones or tendons
• Areas that require durable, full-thickness skin coverage.

The most common indications for CSE axial pattern flaps are (Figure 3-5):

• Large debilitating injuries to hind leg
• Large skin defects after wide surgical excision of neoplasia.

General preoperative considerations

• Perform a complete physical exam and obtain a minimal database, including a complete blood count and serum biochemistry profile.
• CENTRAL POINT: In patients with skin defects caused by significant trauma, rule out trauma to other organ systems (eg, bladder rupture, diaphragmatic hernia). To donourgent reconstruction of an acute traumatic wound. Focus first on proper early care of open wounds and stabilizing the patient.
• Prior to any major reconstructive effort, contamination in a traumatic wound is limited with appropriate antibiotic therapy, local wound care, and dressings.

surgical technique

Consider skin coverage

1. CENTRAL POINT: Prior to surgery, ensure that the axial CSE vessel is healthy along the way by visually inspecting the area. If trauma or skin loss is close to the inguinal ring or pectoral chain and the viability of the vessel is questionable, color Doppler imaging or angiogram studies can help determine whether the axial vessel has been damaged. If there is any doubt as to the viability of the vessel, use the contralateral healthy breast chain for skin transfer.
2. Determine the approximate length of skin perfused by the caudal superficial axial vessel (angiosome) by measuring from the superficial inguinal ring to the area midway between the first 2 mammary glands (the most cranial extension of the skin supplied by this vessel) (Figure 1A). This skin length is the same in men and women. In men, however, one or more small branches of the CSE vessel supply the preputial skin. These branches must be carefully ligated to allow complete rotation of the base of the flap in men.
3. Measure the distance from the bottom of the flap to the furthest point from the open wound. I prefer to add approx. 20% of the skin flap length needed to cover the defect because a portion of the flap length is lost when the flap is rotated in place and the flap can be expected to shrink slightly. Determine the ability of the flap to cover the defect based on these initial measurements.
4. Determine the maximum flap width by measuring from the abdominal midline to the nipple; then extend the measured length laterally to the nipple (Figure 1A).
5. If a "paddle" of skin is needed to cover a large round defect wider than the maximum flap width, consider folding the terminal side of the flap into a "U" turn to basically double your effective flap width (Figure 6). To ensure that the planned flap transfer is feasible, add this extra folded skin to the proposed skin flap length measurement.

patient preparation

1. Administer general anesthesia and position the patient in a supine or lateral position to allow simultaneous access to the desired donor mammary chain and the skin defect.
2. In addition, first-generation cephalosporin antibiotics are administered at induction of anesthesia and then every 90 minutes until the wound is surgically closed.
3. Cut and prepare a generous area around the proposed skin defect and the donor skin region. Plan to include a lot of adjacent skin in the aseptically prepared field because once the donor site is closed, surrounding skin will be mobilized into the field. When the skin defect involves the hindlimb, hang and prepare the limb aseptically to facilitate skin transfer and wound closure.
4. Aseptically cover the entire field, with ample skin included around the exposed donor and recipient sites.

Recipient wound preparation

1. Use aseptic technique to debride and irrigate the wound if it is not completely covered by healthy granulation tissue. Tissue culture taken from the wound bed, particularly if the wound is considered to be contaminated.

• If the flap is used to reconstruct an open wound, wash the wound bed with an appropriate antiseptic solution and routinely cut and aseptically prepare the surrounding skin.
• If the wound is more chronic and the skin wound edges are partially epithelialized, turn the wound edges and remove thin epithelialized tissue by extending the wound bed margins with a scalpel blade.

2. Open the skin edges of the wound wide by several millimeters to create a free edge to which the flap should be sutured. Cover the prepared recipient wound with moistened laparotomy pads when starting flap preparation (donor skin).

Donor skin preparation

1. Draw the suggested dimensions of the brim with a sterile drawing pen (Figure 7). The medial border is located on the ventral abdominal midline from the pubis to a point between the first and second mammary glands. In male dogs, the medial caudal border includes the skin just lateral to the base of the foreskin.

2. The lateral edge of the flap should be parallel and the same length as the medial edge (midline). Draw the lateral boundary line as far from the nipple line as the measured distance from the midline to the nipple line. Essentially, the width of the flap is twice the measurement from the midline to the nipple line.

3. Taper the lateral border of the skin towards the inguinal ring area, which facilitates closure of the donor defect in the inguinal region after flap transfer.

4. After determining the proper flap length, a line connecting the medial and lateral lines of the skin flap is drawn on the distal aspect of the proposed skin flap. Shape the distal end of the flap with rounded edges to facilitate closure of the cranial aspect of the donor defect without folds.

Incise and undermine the flap

1. Use a scalpel blade to cut the skin along the edge of the lines drawn to outline the flap. As the skin incision tapers caudally into the groin area, do not damage nearby underlying CSE vasculature.

2. Starting at the distal aspect of the flap (the most cranial aspect), gently and neatly detach the subcutaneous tissue directly from the abdominal wall. On the most cranial aspect, expect firm attachment of the subcutaneous tissue to the underlying pectoral muscles. Detachment is easier as the dissection progresses caudally because the subcutaneous tissue is loosely connected to the underlying fascia. Avoid using thumb forceps to grab skin edges; instead, use hooks or digital manipulation to handle and retract the flap (Figure 8).

3. Cover donor skin edges and defects with moistened laparotomy pads while peeling off the flap.

4. KEY POINT: As the detachment progresses towards the annular region of the groin, extra care must be taken when directly dissecting the subcutaneous tissue around the base of the flap and the epigastric trunk of the pudendum. Consider leaving the inguinal fat pad (process vaginal) and fat plug intact, provided the underside of the flap can be rotated into place effectively.

Create a bridge incision if needed

1. If the base of the flap does not extend to encompass the skin defect, a bridging incision is required to allow a path for the flap to reach the recipient bed.

2. Make an incision in the skin and subcutaneous tissue directly between the base of the flap and the recipient bed. Determine where the base of the flap best fits within its rotated arc to determine where the bridging incision should be made (Figure 9).

3. Make an undercut in the skin adjacent to the bridge incision to allow the width of the base of the tapered skin flap to fit snugly against it.

Transfer the flap to the recipient bed

1. Turn the flap over the wound.CENTRAL POINT: The flap can be stretched slightly to accommodate the wound defect, but it does not allow tension or buckling of the CSE vessel if the flap is rotated 180 degrees or more.

2. Ensure that the distal aspect of the flap is positioned in the most distal area of ​​the open wound. Try different flap positions until you find the best flap location (Figure 10).

3. Once the best flap position is found, move the affected limb in various directions to ensure the flap is not under tension (especially in normal standing and standing positions).

4. If the open wound is rounded and wide and a "U-turn" of the distal flap is planned to create a "paddle", additional flap maneuvers may be required before closure is initiated (Figure 6).

5. If the flap does not completely cover the open wound, use other reconstructive options for closure.

6. Although many surgeons prefer routine closed suction drainage of these flaps to prevent seroma, I have found that drainage is usuallynonecessary if atraumatic subcutaneous dissection and detachment are performed and hemostasis is careful. If drainage is chosen, ensure that there is a good seal around the edges of the wound during closure. To donoleave the suction drain closed by the valve; instead, leave it to the side of the flap (Figure 4).

Suturing the wound edges

1. KEY POINT: I prefer not to drop or use walking stitches subcutaneously to try to reduce movement and dead space under the flap and inguinal region. These sutures can inadvertently damage the blood supply to the valve.

2. Starting with the most distal aspect of the flap, use widely spaced interrupted hypodermic sutures to secure the flap in its permanent location (Figure 11). Alternatively, some surgeons use small towel clips to help hold the flap edges and the donor defect together during suturing.

3. Once these sutures have loosely positioned the flap, begin to close the hypodermic layer with 3-0 or 4-0 absorbable monofilament suture material in a continuous pattern. Close the skin with a single interrupted or single continuous pattern (my preference) 3-0 or 4-0 non-absorbable monofilament or skin staples.

4. Keep the donor defect covered with moistened laparotomy pads until the flap hypodermis and defect margins are closed. Trim the donor skin margins if tension occurs during defect closure.

5. Continue closure of the donor defect with hypodermic and skin sutures using the previously mentioned materials (Figure 12).

post-operative care

bandage

Once the operation is finished, place an Elizabethan collar on the patient and cover the donor breast region with a stocking or light bandage (at the surgeon's discretion). I prefer not to bandage the flap postoperatively, as dressings often "ride up" in the inguinal region, which can cause discomfort and, more importantly, put pressure on the vasculature of the flap, compromising flap perfusion.

cold therapy

The donor area can be cold packed for several days after surgery, but I prefer to avoid cold compressing the flap area, which can cause vasoconstriction of the subdermal blood supply and compromise the flap.

medical therapy

CENTRAL POINT: Expect the extensive skin incision and detachment to cause significant pain after surgery. Therefore, systemic opioids and non-steroidal anti-inflammatory drugs are administered postoperatively for 24 to 48 hours. Appropriate oral analgesics are given for 5 to 7 days after surgery.

The use of postoperative antibiotics is limited to patients with evidence of wound infection or patients in whom aseptic technique breaks down during the surgical procedure.

home service

Owners are instructed to carefully monitor wounds and seek veterinary care if they notice increased discomfort, inflammation or drainage after surgery. Patients should be strictly limited to walking on a leash and prohibited from climbing stairs, jumping or running until suture removal 14 days after surgery. The patient can then gradually increase the activity.

complication management

Seromas, hematomas, and disc wounds are possible postoperative complications seen after extensive reconstructive surgery, as described in this article (Figure 13).

• When a seroma or hematoma forms, do not invade the wound; Consider cage rest and warm wound packing starting several days after surgery.
• Consider early reconstruction of minor injuries at the wound edge if there is no evidence of infection.
• The distal aspect of the flap is more susceptible to avascular necrosis and dehiscence. Debride necrotic tissue and keep the wound open until healthy granulation tissue forms. The surgeon may decide to leave the wound open for secondary intention healing or to attempt a secondary closure.

forecast

If performed correctly, CSE axial pattern flaps have a low risk of flap necrosis (< 10%) and infection. Minor complications, such as seroma, partial incision failure, flap swelling, and bruising, are generally amenable to conservative treatment and do not affect the long-term prognosis.

CSE = caudal superficial epigastric

Suggested reading

• Aper RL, Smeak DD. Clinical evaluation of superficial epigastric caudal axial patter reconstruction of skin defects in 10 dogs (1989-2001).GUL2005; 41(3):185-192.
• Campbell BG. Skill Lab: How to Perform a Caudal Superficial Epigastric Flap. Available at veterináriamedicine.dvm360.com/skills-laboratory-how-perform-caudal-superficial-epigastric-flap?rel=canonical.
• Pavletic MM.Atlas of Small Animal Wound Care and Reconstructive Surgery, 3rd ed. Ames, IA: Wiley-Blackwell. 357-4
• Pavletic MM. Caudal superficial epigastric arterial pedicle engraftment.Veterinary Surgeon1980; 9(3):103-107.