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Pectoralis Major Myocutaneous Flap and Myofascial Flap

last modified on: Tue, 04/16/2024 - 09:35

see also: Case Example of Pectoralis Myocutaneous Flap

Note: last updated before 2013

GENERAL CONSIDERATIONS

  1. Indications
    1. The pectoralis major myocutaneous flap and myofascial flap variation are utilized in a large variety of head and neck reconstructive procedures that can include coverage of mucosal and/or cutaneous defects. The extent of coverage and the reach of the flap are dependent on the anatomy of the patient, modifications of the standard techniques of elevation, and inset. The upper limits are generally considered the zygomatic arch area externally and the superior tonsillar pole internally - patient body habitus may either limit extension short of these landmarks, or permit extension beyond.
    2. The myofascial flap variation carries no skin paddle and is utilized primarily to close small mucosal defects, to protect major vascular structures, and to support primary mucosal closure in a patient at increased risk of wound breakdown (prior radiation, diabetic, weight loss).
  2. Contraindications
    1. A defect that is too large or outside the potential reach of the reconstructive tissue
    2. Very obese patients will have a difficult-to-handle and possibly nonviable skin paddle
    3. Patients with prior chest wall trauma and/or prior chest wall surgery (mastectomy, breast implants, subclavian lines, cardiac pacemaker, etc) may have absent, scarred or poorly vascularized pectoralis major muscle
    4. Removal of the muscle will affect the strength of the shoulder and arm; this weakness may affect the ability of the patient to work or participate in recreational activities
    5. Congenital absence of pectoralis muscle (Poland's syndrome)
  3. Advantages
    1. This flap offers one-stage reconstruction.
    2. The patient's position need not be changed intraoperatively.
    3. This flap provides a large cutaneous island that can be used for defects involving 2 epithelial surfaces.
    4. The muscular part covers neck structures protecting the carotid artery, especially in patients who have undergone radiation therapy.
  4. Disadvantages
    1. The flap can conceal recurrences, making follow-up in the neck area more complicated.
    2. In women, the flap might include breast tissue, which may lead to breast asymmetry.
    3. In males, hirsute chest skin is placed intraorally.
    4. This flap causes loss of pectoralis muscle function in arm adduction and/or rotation.
    5. In patients who are overweight, the flap is bulky, which leads to postoperative contour deformities.

PREOPERATIVE PREPARATION

  1. Additional Preoperative Evaluations
    1. None required (see Contraindications)
  2. Consent Inclusions
    1. The use of the pectoralis muscle and chest wall skin is necessary for reconstruction of a defect in the head and neck region that otherwise is unlikely to heal or would have significantly increased risks of complications during the healing period.
    2. The surgery will require a skin incision on the chest wall that will result in a skin scar.
    3. Absence of the muscle will affect the chest wall contour to a minor degree.
    4. The flap used will decrease the strength of the shoulder and upper arm and may affect the patient's ability to work and recreate.
    5. The reconstruction has a risk of partial or complete failure that would require additional surgery and/or wound care.
    6. There is a risk of wound infection, hematoma, and/or hemo/pneumothorax.

NURSING CONSIDERATIONS

  1. Room Setup
    1. See Basic Soft Tissue Room Setup
  2. Instrumentation and Equipment
    1. Standard
      1. Major Instrument Tray 1, Otolaryngology
      2. Major Instrument Tray 2, Otolaryngology
      3. Bipolar Forceps Trays
    2. Special
      1. Tracheotomy Tray
      2. Retractor Tray, Large
      3. Varidyne vacuum suction controller
      4. Doppler probe and control unit (available only)
      5. Cummings retractor, medium and large
  3. Medications (specific to nursing)
    1. Antibiotic ointment (see Antibiotic Prophylaxis in Head and Neck Surgery protocol)
    2. 1% lidocaine with 1:100,000 epinephrine
  4. Prep and Drape
    1. Standard prep, 10% providone iodine (neck and chest)
    2. Drape
      1. Head drape
      2. Towels around the neck (from the chin), chest from beyond the contralateral sternal border, below xiphoid, shoulder, and midaxillary line
      3. Split sheet
  5. Drains and Dressings
    1. Varidyne vacuum suction drain (10 mm): two each in both the neck and chest
    2. Antibiotic ointment to suture lines
  6. Special Considerations
    1. Skin graft may be necessary.

ANESTHESIA CONSIDERATIONS

  1. General Anesthesia
    1. Tube position: per primary resection, tubing needs to remain off ipsilateral chest and neck.
    2. Paralysis
    3. EKG electrodes: no precordial leads; leads may be placed on the posterior upper back and shoulder
    4. Central line: if needed, use long-arm CVP or femoral catheters
  2. Systemic Medication
    1. Antibiotics (see Antibiotic Prophylaxis in Head and Neck Surgery protocol)
    2. Steroids: consider Decadron, 10 mg, IV
  3. Positioning
    1. Bed at 0, 90, or 180° to anesthesia machine, depending on need of other surgical resection
    2. Patient supine
    3. Padding and strapping, routine
  4. Estimated Blood Loss
    1. 300 cc (150-900)

OPERATIVE PROCEDURE

  1. Pertinent Anatomy
    1. Landmarks
      1. Identify the clavicle, ipsilateral sternal border, xiphoid, and humeral insertion of the pectoralis muscle.
      2. The course of the pectoral branch of the thoracoacromial artery can be identified by drawing a line from the xyphoid to the acromion.  A second line perpendicular to this line is drawn that bisects the clavicle.  The course of the artery corresponds to the line drawn from the midpoint of the clavicle continuing to the medial portion of the acromion to xyphoid line.
    2. Skin paddle
      1. Size and location of skin paddle depends on reconstructive requirements. Standard skin paddle is located at the infero-medial border of the pectoralis major muscle that is inserting on the lateral border of the sternum and the second to sixth costal cartilage.
      2. Skin overlying any portion of the muscle may be utilized.
      3. The larger the skin paddle harvested, the higher the likelihood the skin will survive the transfer due to the increased number of myocutaneous perforators.
      4. For additional length, the skin paddle may be extended as a random-pattern flap beyond the inferior edge of the muscle belly.
      5. Small flaps extended beyond the inferior muscle edge may exhibit an absence of myocutaneous perforators.
      6. The myofascial flap is raised without a skin paddle.
  2. Blood Supply
    1. Pectoral branch of the thoracoacromial artery (primary blood supply). The artery runs in the fat on the underside of the muscle.
    2. Sacrifice of the lateral thoracic artery (secondary blood supply) is usually required to gain necessary length.
    3. The supreme thoracic artery also supplies the pectoralis major, but is usually divided when the flap is raised.
  3. Flap Elevation
    1. Design the size and location of the skin paddle over the pectoralis major muscle.
    2. Initial incision is made from lateral edge of designed skin paddle toward the anterior axillary line. Usually this incision is above the nipple in the male and below the breast in the female patient. The incision is carried down to the pectoralis major muscle. This allows for identification of the medial and inferior extents of the muscle, after which the design of the skin paddle can be moved inferiorly or superiorly so as to rest above muscle tissue.
    3. The inferior, medial, and lateral incisions are made through the muscle and fascia of the pectoralis major muscle and down to the chest wall.
    4. The superior skin flap incision is made down to the muscle fibers of the pectoralis major muscle.
    5. The skin paddle should be temporarily secured to the fascia of the muscle with 3-0 vicryl or gut suture.
    6. A skin/fascia tunnel is created under the superficial pectoralis major muscle fascia, preserving the perforators to the overlying deltopectoral flap The tunnel must extend from the superior flap incision, over the clavicle and into the neck.
    7. The muscle flap is then elevated off the chest wall beneath the deep pectoralis major muscle fascia. Care should be taken in controlling the bleeding from the chest wall perforators at the muscular attachments to the chest. Vessel retraction into the chest can lead to hemothorax.
    8. As the muscle is elevated inferiorly to superiorly, the pedicle should be identified by visualization and palpation on the deep surface of the muscle.
    9. As the muscle fibers are cut along the sternal attachments, care should be taken not to cut the internal mammary perforators adjacent to the sternum that supply the deltopectoral flap (see Deltopectoral Flap protocol).
    10. The pedicle should be in view while transecting the lateral muscle attachments.
    11. The use of a Shaw knife (heated knife) may be useful in this dissection.
    12. The lateral thoracic artery is usually cut to increase length and rotation and should be tied to prevent late bleeding and/or hematoma.
    13. Do not overly rotate, kink, or compress proximal flap.
    14. Increased length can be gained by division of the clavicular portion of the pectoralis major muscle above the pedicle by debulking the muscle fibers over the proximal pedicle and by splitting and removing the middle one-third of the clavicle (this is rarely necessary and increases the risk of vessel kinking and flap failure).
    15. Excessive fat between the muscle and skin can lead to skin paddle loss without muscle loss. When securing the flap in place, muscle fascia should be secured, independent of the skin paddle.
  4. Closure
    1. Mobilization of the surrounding tissue of the chest should allow for primary closure in almost all cases. Split thickness skin grafts should be used, if primary closure is not possible.
  5. Drains
    1. The neck and chest are drained with suction drains, two in each location. The drains must not cross the pedicle.
  6. Dressing
    1. Antibiotic ointment

POSTOPERATIVE CARE

  1. Dressings
    1. Antibiotic ointment
  2. Flap Monitoring
    1. No tracheotomy ties, gown ties, or pressure on pedicle in neck or over clavicle
    2. "No Pressure" sign taped on patient's chest near pedicle or written with marking pen on skin
    3. The flap is monitored by observation of color and needle-prick bleeding. Poor flap appearance may be improved with the use of dextran, steroids, and/or hyperbaric oxygen. Pressure points and excessive torque should be assessed and improved if possible with changes in the head and arm positions or neck suture removal.
    4. Flap failure is most likely to occur at the superior aspect of the flap/mucosa closure.

REFERENCES

Ariyan S. Further experiences with the pectoralis major myocutaneous flap for the immediate repair of defects from excision of head and neck cancers. Plast Reconstr Surg. 1979;64:605-612.

Ariyan S. The pectoralis major myocutaneous flap. Plast Reconstr Surg. 1979;63:73-81.

Lore JM. General purpose flaps. In: Lore JM, ed. An Atlas of Head and Neck Surgery. 3rd ed. Philadelphia, Pa: WB Saunders Co. 1988:318.

Zbar RI, Funk GF, McCulloch TM, Graham SM, Hoffman HT. Pectoralis major myofascial flap: available tool in contemporary head and neck reconstruction. Head Neck. 1997;19:413-418.

Jacono A, Moscatello A, Pedicled myocutaneous flaps in head and neck surgery. Operative Techniques in Otolaryngol. Head and Neck Surgery. Volume 11, Issue 2, Pages 71-150 (June 2000) .