Pectoralis major myocutaneous pedicle flap

The need for reconstruction of mandibular defects is either due to trauma or tumor resection.

The vast majority of oral cavity tumors are squamous cell carcinoma, and these arise from the mucosa. These tumors are therefore adjacent to the mandible and significant growth frequently leads to invasion of the bone.

A composite resection (segmental mandibulectomy) is the treatment of choice for oral malignant tumors that invade the mandibular cortex and marrow space. It provides an oncologically sound margin for these tumors; however, it disrupts the continuity of the mandible.

Reconstruction of the mandible allows for the restoration of form and function. It must address all the tissue losses in order to provide for the best function.

• Restoration/maintenance of airway
• Restoration of mandibular continuity
• Restoration of dentition
• Restoration of chewing (mastication) and swallowing (deglutition)
• Restoration of facial contour
• Consistently obtain a healed wound

However, when bony reconstruction is not desired or possible, the restoration of the intraoral soft tissue defect with a vascularized soft tissue graft alone is a reasonable alternative.

This creates the so-called "swinging defect". The mandible shifts to the affected side resulting in a cosmetic deformity, but often allows for acceptable speech and adequate swallowing.

When the radial forearm fasciocutaneous free flap is used, the presence of the lateral antebrachial cutaneous nerve provides the option of innervating the flap and restoring sensation to the oral cavity.

The location and size of the tumor will dictate the surgical approach necessary for the performance of the ablative procedure.

The two following approaches are frequently used for the mandible:

• Lip split approach
• Visor approach

The proposed mandibulectomy margins are marked on the mandible. Care is taken to resect at least 1 cm of normal bone on each side of the tumor.

The tumor is visualized and palpated intraorally and 1.5 cm soft tissue margins are marked (eg. with electro cautery) around the tumor in the oral cavity.

In a dentate patient, the teeth in the line of the osteotomies are extracted.

Bone cuts are now carried anterior and posterior to the tumor using a saw. Care is taken to resect at least 1 cm of normal bone on each side of the tumor.

The bone is retracted laterally, thus exposing the medial soft tissue resection margin.

Soft tissue cuts are made through the previously marked resection margins in the floor of mouth, the mylohyoid muscle and deep tongue muscles if necessary.

The specimen is submitted en bloc for permanent pathological examination.

Surgical soft tissue margins are now checked with frozen sections to ensure the adequacy of the tumor resection.

Pectoralis major myo cutaneous pedicle flap is harvested in the standard fashion with the following consideration:

• An adequate length of the flap must be ensured to allow the skin paddle to reach to the oral cavity defect without tension.
• The flap pedicle is passed from the chest wall to the defect trough a subcutaneous tunnel in the neck (usually in the case of simultaneous neck dissection) or alternatively, the pedicle stays outside the neck adequately protected.

The skin/soft tissue component of the flap is placed into its preplanned position in the oral cavity with care not to create undue torsion or tension of the pedicle.

In most oral cavity and oropharyngeal defects, the oral mucosa is closed directly to the skin of the flap with interrupted absorbable suture in a vertical mattress fashion (eg. 3-0 Vicryl). A water tight closure is essential to avoid a salivary leak into the neck with subsequent infection in the surgical site and an orocutaneous fistula.

Care must be taken during closure to avoid injury to the vascular pedicle

The flap pedicle and muscle, which now drapes the neck, provides the necessary blood supply; however, it creates tension on the wound closure secondary to gravity and muscle pull. This must be addressed by suspending the pectoralis muscle to the underlying deep neck using resorbable sutures (eg. 3-0 Vicryl).

The use of the following perioperative medication is controversial. There is little evidence to make strong recommendations for postoperative medications.

• Analgesia as necessary
• Antibiotics (many surgeons use perioperative antibiotics). There is no clear advantage of any one antibiotic but evidence supports their use for 24h. The spectrum should be according to the oral bacterial flora, but the physician should be aware of changes that may occur after the use of radiation therapy.
• Steroids may help with postoperative edema.
• Regular perioral and oral wound care has to include disinfectant mouth rinse, lip care, etc.
• Antibiotic ointment is used on the wounds for 72 hours
• If a free flap is utilized for the reconstruction, 80-100 mg of aspirin/day is recommended.

Remove any sutures from skin after approximately 7 days if nonresorbable sutures have been used. If the patient has had previous radiation, the sutures should be left in for 10 – 14 days.
Wound should be cleaned at least twice daily with hydrogen peroxide or mild soap and water. Moisturizing lotion should be used on the skin wounds to minimize excessive scarring after sutures are removed.
Avoid sun exposure and tanning to skin incisions for several months.

Diet depends on the reconstructive method. In general patients with superficial wounds can begin an oral diet within 48h postoperatively. Patients who have undergone a more significant surgery eg. flap reconstruction are kept NPO for 5-10 days and nutrition is administered via nasogastric tube. Oral feedings are begun using thickened liquids only after swallowing is assessed by the surgeon or the speech pathologist, and the risk of aspiration is minimal. Diet can be advanced as tolerated by the patient.

Typically the patients are seen in clinical follow-up one week after discharge, and then on a weekly basis until such time the clinician determines that less frequent follow ups are needed.

Patients with intraoral incisions and/or wounds must be instructed in appropriate oral hygiene procedures. A soft toothbrush (dipped in warm water to make it softer) or water flosser should be used to clean the surfaces of the teeth. Chlorhexidine oral rinses should be prescribed and used at least 3 times a day to help sanitize the mouth. For larger debris, a 1:1 mixture of hydrogen peroxide/chlorhexidine can be used. The bubbling action of the hydrogen peroxide helps remove debris.

When a free flap is utilized, it should be regularly monitored to ensure vascular integrity. Physical examination, assessing the flap color, turgidity, and capillary refill should be routine for at least the first 48 hours postoperatively. Hand-held Doppler probes can be used to assess blood flow. In case of doubt of the vitality of the flap, pin-prick assessment with a 25 gauge needle to look for bright red bleeding.. In cases of buried flaps, an implantable Doppler placed just distal to the venous anastomosis can be utilized.

Closed suction drains are routinely used at the donor site. The drain is removed when output is <30cc per 8 hour period, for three consecutive periods. Patients are typically discharged from the hospital 5-10 days after surgery, depending on their postoperative course and comorbidites. Close outpatient follow-up after discharge is recommended for evaluation of surgical sites.

Radial forearm free flap
The radial forearm free flap donor site should be closed with a skin graft and a bolster placed over the area. The arm is then cast or placed in a volar splint for 7 days prior to removal to ensure graft take.

Fibula free flap
After a fibula free flap, the donor lower leg should be cast with the ankle slightly dorsiflexed for 5 days. The patient can touch-down their body weight as tolerated. After the cast is removed they can ambulate and work with physical therapy to optimize leg function. A splint should be placed to keep the foot flexed when in bed. The routine use of a compression stocking for one month postoperatively will reduce the amount of lower leg dependent edema and aid in improved wound healing.

Scapula free flap
In the initial postoperative recovery, the ipsilateral arm should be positioned anteriorly and medially, usually supported on the patient’s abdomen by a pillow. Once the patient is ambulating, the arm is supported by a shoulder sling which supports the elbow and prevents inferior drift of the arm. Inpatient physical therapy is initiated once the patient is mobile. A post-operative physical therapy regimen is established with the patient to be maintained after hospital discharge. The sling is used for 2-3 weeks and physical therapy maintained until postoperative function is optimized, usually 4-6 weeks.

Iliac crest
The iiliac crest donor site requires that the patient not strain or lift heavy objects for at least 4 weeks to avoid hernia formation. Patients are typically limited to a bed or chair for 48h postoperatively and then physical therapy is begun with the patient initially ambulating with the aid of a walker or cane and progressing as tolerated.

Latissimus dorsi
No specific rehabilitation is necessary following the use of this flap.