Pectoralis major myocutaneous pedicle flap

Resections involving primarily skin and underlying mandible are uncommon. Potential entities producing this condition are, tumors arising in the mandible, submandibular gland malignancies, metastatic level I lymph nodes with extracapsular invasion extending to the overlaying skin. As well as cutaneous malignancies eg. lip or cheek carcinoma invading the underlying mandible .

The resulting small intraoral mucosal defect is repaired primarily (floor of mouth to lateral cheek mucosa). Therefore, from a reconstructive view, making this a two layer defect involving the bone and overlying skin.

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.

The general goal of reconstruction is the:

• Restoration/maintenance of airway
• Restoration of mandibular continuity
• Restoration of dentition
• Restoration of chewing (mastication) and swallowing (deglutition)
• Restoration of facial cutaneous defects and contour
• Consistently obtain a healed wound
• Restoration of the oral stoma (if lip involved)

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.

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

Incisions are marked out 1.5 cm around the entire visible and palpable tumor.

An extension of the incision is then carried posteriorly towards the mastoid anteriorly to the submental region. Additional extensions can be made according to surgeon's preference or the need of simultaneous neck dissection.

When the neck dissection is performed, care must be taken to dissect and preserve potential recipient vessels.

It should be noted that on most occasions one or more branches of the facial nerve will need to be sacrificed due to tumor involvement.

Dissection is carried through the skin incisions marked around the tumor and continued through the subcutaneous tissues until the mandibular bone is encountered.

The periosteum is incised keeping at least 1 cm margins around the involved mandibular bone. The periosteum and soft tissues on the remaining native mandible are elevated laterally and medially to allow for subsequent application of the locking mandibular reconstruction plate. Proposed lines for mandibular osteotomies are marked.

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. Soft tissue cuts are made through the previously marked resection limits in the mylohyoid muscle and the mucosa adjacent to the alveolus.

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 considerations:

• An adequate length of the flap must be ensured to allow the skin paddle to reach to the skin defect without tension
• The proximal portion of the skin paddle can be de-epithelized and folded to bolster the intraoral closure.
• 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 mucosa and submucosa of the intraoral wound can be closed with a single layer of 3-0 Vicryl in a mattress fashion. Usually the remaining gingiva is sutured above the muscular cuff of the bone flap.

A water tight closure is essential to avoid a salivary leak into the neck with subsequent infection in the surgical site and orocutaneous fistulae.

The flap is positioned into the cutaneous defect with care not to create undue torsion or tension within the pedicle.

The proximal portion of the skin paddle can be de-epithelized and folded to bolster the intraoral closure.

The skin closure is carried out in layered fashion using absorbable sutures eg. 3-0 Vicryl for the deep layers, and nylon for the skin.

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.