Rotational and Free Flap Closure of the Abdominal Wall

Published on 09/04/2015 by admin

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Chapter 15 Rotational and Free Flap Closure of the Abdominal Wall image

Christopher G. Zochowski, MD, Hooman Soltanian, MD, FACS

1 Preoperative Considerations

1 Comorbidities

image Skin and subcutaneous fat may be of varying thicknesses and qualities in patients because of body habitus, scarring, steroid use, malnutrition, advanced age, and other factors.
image Bleeding tendencies should be addressed preoperatively.
image Conversely, a thrombogenic state will put any flap at risk and may warrant a hematologist to assist in the pre- and postoperative care.

2 Open Wound Management

image The timing of the closure of abdominal wounds is on a case-by-case basis.
image Appropriate dressings should be applied to the wound before surgery to prevent desiccation of the soft tissues and intraabdominal contents.
image Negative pressure dressings allow for easier management of large abdominal wounds, but the wound must be monitored closely when the dressing is applied over exposed bowel.
image Some wounds require frequent debridements to determine the extent of viable tissue and clearance of infection.
image Open wounds increase the nutritional and fluid requirements of the patient.
image Chronic open wounds should be converted to acute clean wounds before closure.

3 Timing

image Optimize the patient before closure of the abdominal wall in regard to nutrition, cardiovascular status, and pulmonary function. The closure may lead to prolonged intubation, and this risk is increased in patients with chronic obstructive pulmonary disease (COPD) and smokers.
image Closure should be timed after bowel edema has subsided (stage if needed).
image Avoid intraoperative nitrous oxide use. Consider a nasogastric tube.

4 Defect Assessment and Flap Selection

image Assess the extent of missing or aberrant structures and define the anatomical region of the tissue loss.
image Assess the quality of remaining structures and loss of domain.
image Take note of an ostomy position if present.
image Assess for enterocutaneous fistulae.
image Rule out previous damage to the blood supply of any potential flaps.
image Pedicled flaps are limited by their arc of rotation and the size and location of the defect.

2 Muscular Flaps (Table 15-1)

image Figure 15-1 shows the cross-sectional anatomy of the thigh demonstrating the possible muscles for coverage of abdominal wall defects

TABLE 15-1 Flap Types

image

image

Figure 15-1

1 Tensor fascia lata

image Anatomy

image The flap can be musculocutaneous.
image Sensory innervation includes the lateral cutaneous branch of the twelfth thoracic nerve and the lateral cutaneous sensory nerve of the thigh (L2 and L3). Motor innervation is supplied by the distal branch of the superior gluteal nerve (L4 and L5).
image Arterial blood supply is from the ascending branch of the lateral femoral circumflex artery, which is 1.5 to 2.5 mm diameter. The vein is slightly larger than the artery when traced to the origin on the lateral femoral circumflex.
image Pedicle length can be up to 10 cm. The pedicle enters the tensor fasciae lata (TFL) muscle at the level of the junction of the proximal and middle thirds of an axis drawn from the anterior superior iliac spine (ASIS) to the lateral aspect of the patella. It emerges from beneath the rectus femoris muscle, anterior to the vastus lateralis and enters the muscle via the deep surface medially 6 to 8 cm from the ASIS.
image The descending branch of the lateral femoral circumflex artery continues beyond the TFL muscle to supply the skin of the anterolateral midthigh and the lower thigh. It can be harvested with the anterolateral thigh skin to enlarge the perfused vascular territory.
image The TFL muscle (Fig. 15-2) is a short, flat muscle that is approximately 12 to 15 cm long. It acts as an accessory flexor and medial rotator of the thigh. It originates from the anterior iliac crest and the deep surface of the fascia lata. At the origin, it lies between the gluteus medius and sartorius, and superficial to the vastus lateralis. It inserts into the iliotibial tract, which inserts distally on Gerdy’s tubercle on the lateral aspect of the tibia.
image The fascia lata is the deep fascia of the thigh. It thickens to form the iliotibial tract laterally and attaches distally to the lateral condyle of the tibia. The TFL muscle is enclosed by the fascia lata, and distally, the muscle fibers coalesce with the iliotibial tract in the middle third of the thigh. The thickness of the fascia lata over the TFL muscle makes it a strong fascial donor site suitable for reconstructing abdominal wall defects.
image

Figure 15-2

image Flap Design

image Skin territory can be up to 15 × 40 cm. A line from the ASIS 10 to 15 cm posteriorly marks the origin of the TFL muscle, with the skin territory extending 2 cm cranial to this line (Fig. 15-3). The lower skin territory is 8 cm above the lateral femoral condyle. Posterior skin territory is a line drawn from the greater trochanter to the fibular head or approximately along the axis of the femur. The anterior border is a line drawn from the ASIS to the lateral aspect of the patella.
image The entry point of the pedicle is at the level of the junction of the proximal and middle third of the line or 6 to 8 cm from the ASIS.
image The rotation arc of the pedicled flap reaches the costal margin if the tensor muscle is completely detached from its origin and raised as an island flap.
image

Figure 15-3

image Marking and Dissection

image The flap is marked as an ellipse over the axis of the TFL muscle and to incorporate the pedicle proximally.
image The patient is prepped and draped supine with a bump under the ipsilateral hip.
image The flap is elevated from distal to proximal.
image The skin and deep fascia are incised together in a plane deep to the iliotibial tract fascia.
image As dissection proceeds cranially, the space between the rectus femoris and vastus lateralis is retracted with a self-retaining retractor to identify the descending branch of the lateral femoral circumflex artery.
image The ascending branch is then identified as one proceeds in a superior direction (Fig. 15-4).
image With the ascending branch identified, its course to the TFL can be isolated
image The proximal flap is then divided by electrocautery while protecting the pedicle.
image The pedicle can be traced to the origin of the lateral femoral circumflex vessels to gain length.
image If more length is needed, flex the patient at the hip.
image

Figure 15-4

image Variations

image Variations include a free flap, chimeric flap, and an osteomusculocutaneous flap.
image Chimeric flaps are on a common pedicle with the anterolateral thigh and/or the rectus femoris flap.
image In an osteomusculocutaneous flap, a portion of the external table of iliac crest can be harvested with the proximal flap.

image Postoperative Care

image The donor site can be closed primarily if planned appropriately. Skin graft may be needed for larger flaps including skin.
image Close the donor site in layers over closed suction drains.
image Ambulation can begin postoperatively.

image Pitfalls

image This procedure results in a long incision on the leg.

2 Latissimus dorsi

image The latissimus dorsi can be used to as a functional free flap, muscle flap, or myocutaneous flap.
image The latissimus dorsi is the largest muscle in the body (up to 20 × 40 cm), but it is quite thin (<1 cm thick). It acts as a humeral adductor and internal rotator, and no significant functional deficit results from harvest. It has six origins, from the lower six thoracic spines and supraspinatus ligaments, posterior layer of lumbar fascia, tendinous attachments of the iliac crest, strips of muscle interdigitating with the external oblique, muscular slips from lower four ribs, and muscular slips from the scapula. The upper and anterior borders are free. The latissimus is deep to the trapezius. It inserts at the floor of bicipital groove of the humerus behind the tendon of the long head of the biceps. The latissimus forms the posterior fold of the axilla with the subscapularis tendon.

image Innervation

image Motor innervation is supplied by the thoracodorsal nerve, a branch of the posterior cord of the brachial plexus (C7); this nerve closely accompanies the thoracodorsal artery.

image Blood Supply

image Arterial blood is supplied through a terminal branch of the subscapular artery (2 to 5 mm diameter), a branch of the axillary artery.
image After 5 cm, the subscapular artery gives off the circumflex scapular branch posteriorly and the thoracodorsal artery (2 to 4 mm diameter) (Fig. 15-5).
image The thoracodorsal artery courses along the posterior aspect of the axilla for 8 to 14 cm and gives off 1 to 2 branches to the serratus before it enters the latissimus dorsi muscle on its deep surface. The serratus branch can be kept to include the serratus as part of a chimeric flap. The artery divides in the substance of the muscle into vertical and transverse branches and can facilitate a split flap.
image Thoracic intercostal and lumbar perforating arteries enter the deep surface of the muscle 8 cm from the posterior midline at the level of the seventh, ninth, and eleventh vertebral spines. They perfuse the inferior and medial latissimus.
image There is usually a single vena comitans with the artery that is slightly larger than the artery.
image If the pedicle is based on the subscapular artery; a length of five to 10 cm is possible.
image

Figure 15-5

image Contraindications

image There is no absolute contraindication as long as the pedicle is patent.
image Relative contraindications include radiation to the site, prior axillary dissection, a patient who is reliant on shoulder function for crutches or who is wheelchair bound, or if a functioning spinal accessory nerve is absent from prior neck dissection.

image Flap Design

image The flap design can cover ipsilateral abdominal defects. If raised as an “extended” variant, it can cross the midline by incorporating the rim of supragluteal fascia.
image If based at the muscle insertion, the pivot point is at the level of the midposterior axillary line.
image If the insertion is incised, the island flap pivot point is 1.5 to 2 cm inferior to the pectoral humeral junction.
image The skin paddle can be 12 × 20 cm and may allow for primary closure of the donor site.
image The skin paddle can be as large as 5 cm anterior and inferior to the muscle without delay and can be made larger with a delay procedure.
image The skin paddle can be made in a transverse or oblique fashion in women so that the scar is hidden under a brassiere.

image Marking and Dissection

image The outline of the anterior and superior edges of the muscle is made. This can be facilitated by having the patient contract the latissimus.
image If a muscle only flap needed, the incision is marked extending from the posterior axillary fold, then inferiorly and posteriorly over the anterior boarder of the latissimus muscle as dictated by the length of the muscle.
image If it is a myocutaneous flap, the skin island can be designed anywhere over the muscle.
image The upper two thirds of the latissimus dorsi muscle contain a higher density of myocutaneous perforators
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