Pectoralis major myocutaneous flap

Considerations

• • Anatomy of the Pectoralis Major m. - see YouTube (4:33) - Pectoralis Major Muscle Anatomy

    • Origin

      • Clavicle

      • Sternum (2-7 costal cartilages)

      • Abdominal rectus sheath

    • Insertion

      • Greater tubercle of humerus

    • Arterial supply

      • Pectoral branches of the thoracoacromial a. from the axillary a. from the subclavian a. 

    • 1981: The vascular anatomy of the pectoralis major myocutaneous flap

    • Innervation

      • Medial and lateral pectoral nerves

    • Mohrenheim’s fossa

      • Fossa between the pec major, deltoid, and clavicle

      • Importance: cephalic vein passes here

  • Indications

  • 2006: Pectoralis major musculocutaneous flap in oropharyngeal reconstruction: revisited 

  • 2009: Pectoralis myofascial flap during salvage laryngectomy prevents pharyngocutaneous fistula

  • Contraindications

  • Strengths 

    • Robust and highly reliable 

    • Ease of harvest 

    • Excellent color-texture match to neck and facial skin

  • Limitations 

    • Bulky 

    • Restricted reach 

  • Relationship to the deltopectoral flap

  • Literature

  • 1997: Pectoralis major myofascial flap: a valuable tool in contemporary head and neck reconstruction

  • 2006: The reliability of pectoralis major myocutaneous flap in head and neck reconstruction

    • 2011: Evaluation of the pectoralis major flap for reconstructive head and neck surgery [Review]

    • 2014: Contemporary role of pectoralis major regional flaps in head and neck surgery [Review]

Preparation

• • Mark the thoracoacromial artery

    • Draw a line from the acromial end of the clavicle to the xiphisternum

    • Draw a 2nd line vertically from the midpoint of the clavicle to intersect the 1st line

  • Design the skin incision and skin paddle 

    • Consider any potential future or concurrent need for a deltopectoral flap 

    • For men

      • Plan a vertically oriented skin paddle, adjacent to but sparing the nipple 

  • For women

    • Plan a horizontally oriented inframammary skin paddle  

    • Consider the secondary defect closure

      • Generally, chest skin defects of ~ 9 cm or less may be closed primarily 

    • Use a sponge or towel to plan the skin paddle to make sure that it will reach the defect

      • Place the sponge on the clavicle and arc around

• • Ioban over the chest (Dr. Fong) 

    • Dr. Fong designs the incision as a curvilinear line from lateral to just medial to the nipple in a man

Procedure

• • Incise through skin to the fascia of the pec major m. 

    • May suture the skin paddle to the pec major m. in to order to minimize shearing force 

  • Expose the pec major m. by elevating skin flaps in the suprafascial plane 

  • Transect the pec major m. 

    • Transect the pec major m. laterally and bluntly elevate from the pec minor m. 

    • Continue to transect the pec major m. inferiorly to accomodate the skin paddle

    • Transect the pec major m. medially to separate from the sternal attachments

    • Continue to transect the pec major m. up to the clavicle

      • Identify and cauterize the intercostal vessels well since they will retract back into the chest

  • Elevate the pec major m. from the pec minor in the avascular plane

  • Identify the thoracoacromial artery and cephalic vein on the deep surface of the pec major m. 

  • Transect the pec major m. lateral attachment to the humerus

    • Protect the pedicle with your fingers

  • Optional: Identify and denervate the flap by clipping and dividing the medial and lateral pectoral nerves

  • Bluntly dissect the subplatysmal plane tunnel superficial to the clavicle superiorly into the neck

    • Generally, about 4 fingerbreadths of space are needed to prevent ischemia of the pedicle

  • Pass the flap into the neck

    • Avoid shearing the skin paddle 

    • Check the pedicle for twisting 

  • Close the secondary defect

    • If needed, undermine adjacent skin to facilitate primary closure 

    • If needed, harvest a STSG for closure 

    • 2 suction drains in the chest, exiting infero-laterally, secured with 2-0 Silk 

    • 3-0 Polysorb interrupted buried deep dermal 

    • 5-0 Fast or 5-0 Prolene simple running vs staples to approximate the epidermis 

Sample operative report

Post-op

• • CPT code

    • 15734 - Muscle, myocutaneous, or fasciocutaneous flap; trunk

Pearls & Pitfalls

• • Pearls

  • Pitfalls

    • Violating the skin of the deltopectoral flap prohibits future use of this flap 

High-Yield

Links

• • YouTube (6:34) - Pectoralis Major Myocutaneous Flap by the AHNS

  • YouTube (9:17) - Pectoralis major flap by Microsurgery made easy 

• eMedicine - Head and Neck Cancer - Reconstruction

• OPEN ACCESS ATLAS OF OTOLARYNGOLOGY, HEAD & NECK OPERATIVE SURGERY - THE PECTORALIS MAJOR FLAP

• Iowa Protocols - Pectoralis Major Myocutaneous Flap and Myofascial Flap

• Iowa Protocols - Case Example Pectoralis Myocutaneous Flap