Note: last updated before 2013

GENERAL CONSIDERATIONS

1. Indications
   1. This flap has its greatest utility in closure of lateral craniofacial and lateral skull base defects.
   2. This flap is also useful in the correction of lateral neck and external facial defects.
   3. The flap has less utility in the closure of oral or pharyngeal defects but has been used for this purpose.
   4. The flap may be used to cover posterolateral scalp defects.
2. Contraindications
   1. Prior sacrifice of the proximal transverse cervical artery in the neck should prompt the selection of an alternative flap. While a separate dorsal scapular artery may remain intact, it is probably not possible to harvest the flap safely. Other alternative reconstructive procedures should be considered (see Anatomic Considerations below).
   2. Prior posterior thoracic or neck surgery that would have compromised the flap muscle or vasculature
   3. For oral cavity reconstruction, a variety of more suitable alternative reconstructions are currently available.
3. Anatomic Considerations
   1. The trapezius is a large triangular thin muscle that originates from the occiput and spinous processes of C7 through T12.
   2. It inserts into the lateral one-third of the clavicle, acromion, and scapular spine.
   3. It functions to suspend the shoulder girdle and assist in elevating and rotating the shoulder.
   4. The motor innervation of the trapezius muscle is through cranial nerve XI, the spinal accessory nerve.
   5. A great deal has been written about the vascular supply to the trapezius and the overlying skin. The transverse cervical artery (TCA) originates from the first part of the subclavian, usually as a branch of the thyrocervical trunk. Although the TCA may originate from the subclavian more laterally or as a branch of a more dominant dorsal scapular artery (DCA), this will not affect the method of harvest unless the flap is mobilized on its vascular pedicle into the neck, which should not be done.
   6. The TCA divides into superficial and deep arteries at the posterior aspect of the posterior triangle. The superficial branch runs on the undersurface of the trapezius and divides into ascending and descending branches. The descending branch supplies the mid and lower trapezius muscle and overlying skin. The ascending branch supplies the superior trapezius along with the occipital and paraspinous vessels.
   7. The deep branch runs under the rhomboid muscles. This artery is also called the DSA. The confusion is introduced because this vessel may have a separate origin than the TCA from the subclavian. This artery sends a branch into the trapezius, which emerges between the rhomboid major and minor. This branch contributes to the blood supply of the lower trapezius muscle and overlying skin.
   8. The dominance of these vessels has been studied and found to have the following distribution: DSA (15/30), TCA (9/30), or both (6/30). The nondominant artery is usually a branch of the dominant one. Therefore, the underlying anatomy is similar in most cases. However, when both arteries are of equal size, the TCA and DSA may originate separately from the subclavian. In this case, the TCA predominantly supplies the skin above, and the DSA supplies the skin below the rhomboid minor muscle.
   9. The venous return is through the transverse cervical vein, which drains into subclavian vein (2/3) or EJV (1/3).
   10. With a robust TCA, the flap may be harvested on this vessel alone, and the branch of the DSA emerging through the rhomboid muscles need not be preserved. Alternatively, this branch should be retained if the integrity of the TCA to nourish the flap is in question. In selected cases, this branch is retained and rotated superiorly with the flap by dividing the rhomboid minor and the distal continuation of the DSA.

PREOPERATIVE PREPARATION

1. Evaluation
   1. Determine extent of prior neck surgery if that has been performed.
   2. Exclude prior surgery of trauma to posterior thorax.
2. Potential Complications
   1. Partial or total loss of the flap due to venous outflow or arterial inflow problems. Proper positioning of the patient following surgery is crucial in preventing pressure compromise of the vascular pedicle. There should be no pressure to the upper posterior thorax in the region of the pedicle particularly in the area where the trapezius muscle is turned and rotated superiorly.
   2. In harvest of this flap, the anterior clavicular and some scapular fibers and their innervation via the spinal accessory nerve may be retained. However, the patient should be aware that partial or total compromise of the shoulder girdle support afforded by the trapezius muscle might be lost.
   3. The incision may extend well down onto the back.
   4. If the flap is raised following a prior neck dissection, the patient should be aware that an alternative flap might need to be used if the vasculature is determined to be inadequate. An alternative flap within the field is the latissimus dorsi. To ensure access to the latissimus dorsi flap, the entire upper posterior and lateral thorax, axilla, and ipsilateral arm should be prepped.
   5. Seroma formation may occur, and the patient should be informed that drainage with either serial aspirations or drain placement might be required.

NURSING CONSIDERATIONS

1. Room Setup
   1. See Basic Soft Tissue Room Setup
   2. Mayfield headrest
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 (available only)
      2. Varidyne vacuum suction controller
      3. Doppler probe and control unit (available only)
      4. Cummings retractors: 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
   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 (7 mm or 10 mm): two each in both the neck and chest
   2. Antibiotic ointment to suture lines
6. Special Considerations
   1. The prep should extend inferiorly to the iliac crest.
   2. The ipsilateral arm, axilla, and lateral thorax should be prepped.

ANESTHESIA CONSIDERATIONS

1. General
   1. The patient will generally be turned 180°, head away from the anesthesiologist.
   2. The patient should be on a Mayfield headrest.
2. Specific
   1. The patient will need to be rolled into a park bench or lateral decubitus position for flap harvest, if not in this position for the extirpation.
   2. An adequate axillary roll needs to be in place for this.
   3. It is helpful if there are no IVs, arterial, or other monitoring lines or devices in or on the ipsilateral arm.

OPERATIVE PROCEDURE

1. Measure Defect
2. Outline the Skin Paddle
   1. Center the paddle between the spinous processes and the medial border of the scapula, over lower-most fibers of the strap muscle, as close to the midline as possible.
   2. The skin paddle may extend up to 10 to 15 cm caudal to the tip of the scapula; however, extension greater than 5 cm beyond the scapular angle may be tenuous (oblique random extension in the distal and lateral portion of the flap). The average size of the paddle is 150 to 200 cm2. Outline a longer ovoid paddle than needed to facilitate cosmetic closure of donor site.
3. Flap Elevation
   1. Begin incision of the skin and subcutaneous tissue at the distal and lateral portion of the paddle.
   2. Identify latissimus dorsi muscle and elevate the paddle medially until the trapezius muscle is found.
   3. Continue with elevation deep to the trapezius muscle in a medial and cephalad direction.
   4. Adjust the cephalad portion of the skin paddle to ensure it overlies the trapezius muscle. The proximal portion of the skin paddle should extend well onto the trapezius muscle to ensure capture of musculocutaneous perforators. If needed, the proximal-most portion may be deepithelialized with retention of the musculocutaneous perforators.
   5. Complete the incision from the cephalad tip of the skin paddle to the neck defect site and elevate the skin and subcutaneous tissue laterally and medially off the medial-superior portion of the trapezius muscle. An alternative to this is to pass the flap through a subcutaneous tunnel. This latter approach affords less visualization of the upper anterior fibers of the trapezius and may create an area of pedicle constriction at the point of rotation if the flap muscle is thick.
   6. Continue the dissection deep to the trapezius muscle fascia, elevating the entire muscle off the latissimus dorsi and rhomboid major. Identify the descending branch of the TCA running on the undersurface of the muscle.
   7. Leave the rhomboid major muscle attachments intact to avoid further scapular instability.
   8. Divide the muscle insertions to the vertebrae and ligate the paraspinous perforators as the flap is being elevated superiorly. The attachments to the scapular spine are also transected if needed to reach the recipient site without tension.
   9. For skin paddles above the scapular tip and a dominant TCA, the branch of the DSA to the trapezius muscle may be ligated as it is identified between the rhomboid major and minor muscles.
   10. For skin paddles below the scapular tip or in cases of a dominant DSA, protect the DSA by dividing the rhomboid minor muscle at either side of the vessel to allow the required arc of rotation without tension on this vessel. The continuation of the DSA running deep to the rhomboid major will likely need to be divided. This will allow the branch of the DSA to the trapezius to relax superiorly.
   11. Intraoperative assessment of the contribution of DSA to the distal trapezius muscle can be done by placing microvascular clamps to the dorsal scapular artery and vein for 10 to 15 minutes and then assess dermal bleeding or flow signal by Doppler in distal flap. This maneuver can be used if there is a question about the safety of dividing this contributing vessel in the face of a less than robust TCA.
   12. Protect the upper-most portion of the trapezius muscle and rotate the flap into position.

POSTOPERATIVE CARE

1. The donor site is closed over one or two 10 mm fully-perforated drains. The drains are removed when drainage is less than 30 cc in 24 hours.
2. The patient should have a large "X" drawn on the back at the point of flap rotation with the instructions: "No Pressure." The patient should also have a sign at the head of bed indicating no pressure or positioning that will put any pressure on the upper ipsilateral back. This must be communicated to all house staff and nurses involved in the patient's care.
3. The head should be supported in a neutral position or slightly turned to the ipsilateral side.

REFERENCES

Avivi JE, et al. The superior trapezius myocutaneous flap in head and neck reconstruction. Arch Otolaryngol Head Neck Surg. 1992;118:702-706.

Baek S, et al. The lower trapezius island myocutaneous flap. Ann Plast Surg. 1980;5:108-114.

Conley J. Use of composite flaps containing bone for major repairs in the head and neck. Plast Reconstr Surg. 1972;49:522-526.

Krepsi YP, et al. The rhombotrapezius myocutaneous and osteomyocutaneous flaps. Arch Otolaryngol Head Neck Surg. 1988;114:734-738.

Netterville JL, et al. The lower trapezius flap: vascular anatomy and surgical technique. Arch Otolaryngol Head Neck Surg. 1991;117:73-76.

Netterville JL, et al. The trapezius myocutaneous flap: dependability and limitations. Arch Otolaryngol Head Neck Surg. 1987;113:271-281.

Panje WR. Myocutaneous trapezius flap. Head Neck Surg. 1980;2:206-212.

Rosen HM. The extended trapezius musculocutaneous flap for cranio-orbital facial reconstruction. Plast Reconstr Surg. 1985;75:318-327.

Urken ML, et al. The lower trapezius island musculocutaneous flap revisited. Arch Otolaryngol Head Neck Surg. 1991;117:502-511.