William Stuart McKenzie and Patrick J. Louis

CC

A 69-year-old Caucasian male presents for evaluation for dental implants. He states, “I am interested in getting implants.”

HPI

The patient was referred by his general dentist for extraction of periodontally involved teeth and evaluation for implant placement. He reports that he has difficulty chewing his food due to discomfort and mobility of several of his posterior teeth.

PMHX/PSHX/Medications/Allergies/SH/FH

The patient reports hypercholesterolemia, prostatic hypertrophy, gastroesophageal reflux disease (GERD), chronic neck pain, and chronic rhinitis/sinusitis. His current medications include aspirin 81 mg, fenofibrate, alfuzosin, and omeprazole. The past surgical history includes a hernia repair. The patient reports allergies to tramadol and hydrocodone. He also reports a history of cigarette smoking but quit 10 years ago. He denies alcohol and illicit drug use. The family history is negative for heart disease, diabetes, and head and neck malignancy.

Examination

General. The patient is a well-nourished, well-developed 69-year-old Caucasian male in no apparent distress.

Vital signs. Blood pressure is 156/87 mm Hg, heart rate 69 bpm, respiratory rate 16 per minute, and temperature 37°C.

Maxillofacial. Normocephalic. Skin is dry and intact, pupils equal, round, and reactive to light and accommodation (PERRLA), no scleral icterus, visual acuity grossly intact, external auditory canals clear bilaterally, tympanic membranes intact, nares patent, cranial nerves II through XII grossly intact bilaterally. Neck is supple and without lymphadenopathy.

Intraoral. Mucosa is moist and pink. No ulcers, masses, or discolorations of the oral cavity noted. Teeth #3, #11 through #15, #19, #20, and #30 are absent. Generalized periodontal disease is noted with root exposure on teeth #2, #4, #18, #21, #28, and #30. A buccal horizontal defect is present at teeth #19, #20, and #30.

Imaging

Panoramic radiograph reveals no pathologic findings of the sinuses, maxilla, temporomandibular joints, or mandible. There is pneumatization of bilateral maxillary sinuses and generalized periodontal disease with periapical radiolucency at teeth #18, #28, and #31.

Labs

No labs are indicated at this time.

Assessment

Caucasian male, 69 years old, with a history of hypercholesterolemia, prostatic hypertrophy, GERD, chronic neck pain, and chronic rhinitis/sinusitis presents for an evaluation for dental implant placement after extraction of periodontally involved teeth. The physical exam reveals vertical insufficiency of the right mandibular and bilateral maxillary posterior alveolar ridges, in addition to a horizontal alveolar deficiency of the right mandibular posterior alveolar ridge (Figure 12-1).

Treatment

Alveolar deficiencies of the posterior mandible present unique surgical challenges. Defects must be accurately assessed for the horizontal and vertical deficiencies of bone and the amount of keratinized tissue available to support the final prosthesis. A host of reconstructive techniques and materials must be considered, and the most appropriate method selected to maximize the individual patient’s outcome (Figure 12-2). The success of endosteal implant restorations and prostheses has made augmentation of the posterior mandible a necessary skill for oral and maxillofacial surgeons. The use of titanium mesh, autogenous bone, allogeneic/xenogeneic bone, and inlay bone grafting is discussed later.

Discussion

With the growing popularity of implant restorations, mandibular ridge augmentation has become a necessary skill for oral and maxillofacial surgeons. The posterior mandible can be a particularly difficult area to successfully augment due to the unique anatomy of the area. A thorough understanding of surgical techniques and bone grafting options is vital to maximizing the final functional and esthetic outcomes for the patient (Figure 12-3).

Bibliography

Jonathan Shum, Tuan G. Bui, Samuel Bobek and R. Bryan Bell

CC

A 40-year-old edentulous man is referred by his general dentist for evaluation of a tongue mass. The patient states, “My tongue hurts.”

HPI

The patient was referred to an oral and maxillofacial surgeon for evaluation of an ulcerative tongue lesion. The patient first noticed the lesion 8 months ago, and only for the past 2 months has the pain become worse. His general dentist had noted a large ulcerative lesion involving the left posterior lateral tongue. An incisional biopsy of the tongue mass was performed, resulting in the diagnosis of a poorly differentiated, invasive squamous cell carcinoma.

PMHX/PDHX/Medications/Allergies/SH/FH

The patient suffers from hypertension, gastroesophageal reflux disease (GERD), and high cholesterol. He is currently taking simvastatin, HCTZ, and Pepcid OTC. The patient also has a 60 pack-year history of cigarette smoking and has indulged in alcohol regularly for more than 20 years (risk factors for oral cancer). The family history is noncontributory.

Examination

General. The patient is a slim, pleasant white man who appears his stated age.

Intraoral. The patient is edentulous and has a prominent ulceration at the left posterior lateral tongue that measures 3 cm in length and 2 cm in width. The red and white lesion is tender and has a necrotic center with firm, everted edges along its periphery (Figure 12-4). The tongue is freely mobile. There appears to be no extension into the floor of the mouth.

Neck. There is no palpable lymphadenopathy.

Nasal fiber endoscopy. The lesion does not extend into the base of tongue; the bilateral tonsillar pillars, epiglottis, valleculae, arytenoids, piriform sinuses, and glottis are without obvious lesions.

Extremity. Peripheral pulses are 2+ for all extremities, and there is no cyanosis, clubbing, or edema. Bilateral Allen’s tests revealed good collateral circulation to the hands.

Allen’s test is used to assess the circulatory blood flow of the hand. The main blood supply to the hand is via the ulnar and radial artery. The ulnar artery supplies the superficial palmer branch, and the radial artery supplies the deep palmer branch. (Communication between the superficial and deep systems allows perfusion of the hand if there is interruption of one of the two main arteries to the hand, such as with the radial forearm free flap harvest.) Allen’s test determines the perfusion of the hand by simulating complete interruption of the radial artery. This is to ensure that the hand remains viable upon harvesting of the radial forearm free flap. Allen’s test is performed by elevating the intended hand and digitally occluding both the ulnar and the radial arteries. The patient is asked to clench and release a fist to cause blanching of the hand. Next, the pressure over the ulnar artery is released, and the capillary refill of the hand is evaluated. A wide range of values for hand reperfusion have been noted, ranging from 3 to 15 seconds. Additional techniques to qualify hand perfusion include the use of finger oximetry and Doppler assessment in conjunction with the Allen’s test. If hand perfusion is predominately based from the radial artery, use of the contralateral forearm or of an ulnar fasciocutaneous free flap should be considered.

Imaging

In general, if the patient has a normal result on Allen’s test, no imaging is necessary prior to radial forearm free flap harvest.

The work-up of squamous cell carcinoma of the tongue includes CT scanning of the head and neck with intravenous contrast (for improved delineation of soft tissue) and a chest radiograph (see the section Squamous Cell Carcinoma in Chapter 11).

In the current patient, axial and coronal CT scans demonstrated a 3 × 2 × 1.5-cm mass with poorly defined margins in the area of the tongue. No cervical lymphadenopathy was noted. The results of the chest radiograph were within normal limits.

Physical examination of the neck has variable reliability, with a sensitivity of 74%, specificity of 81%, and accuracy of 77%. As recommended by the National Comprehensive Cancer Network (NCCN) guidelines, the work-up for cancer of the oral cavity can include CT scans with contrast and/or MRI studies with contrast of the primary tumor location and the neck. CT imaging has a sensitivity of 83%, specificity of 83%, and accuracy of 83% for the detection of cervical metastasis. MRI, which has an effectiveness similar to that of CT, has been described as more sensitive in the identification of small metastatic cervical nodes. The combination of a physical examination with CT imaging increases the detection rate to 91%, whereas the detection rate for a physical examination alone is 75%.

Labs

Routine laboratory studies, such as a complete blood count (CBC), electrolyte studies, and coagulation studies, may be obtained to establish a baseline preoperatively. Liver function tests are obtained as part of the complete metabolic panel (CMP) and are important screening tests for liver metastasis. No specific laboratory tests are essential before radial forearm free flap harvest.

For the current patient, the results of all the laboratory studies mentioned were within normal limits.

Assessment

cT2N0M0, stage II (greatest clinical tumor dimension is between 2 and 4 cm, with no regional nodal metastasis and no distant metastasis on clinical or radiologic investigation) squamous cell carcinoma of the left lateral tongue.

Treatment

Surgery is the primary treatment modality for oral squamous cell carcinoma. Radiation therapy is an alternative with a comparable survival outcome; however, the treatment duration and likely complications of radiation-induced fibrosis and xerostomia make this option less appealing. Most patients opt for surgery, although medically compromised patients who are not suitable candidates for surgery may opt for radiation therapy.

Access to the lesion is considered first. In the current patient, the resection can be completed via a transoral approach. For larger oral squamous cell carcinomas of the oral cavity, it is not uncommon to gain access via a lip split mandibulotomy or “pull through” approach (Figure 12-5). Along with resection of the tumor, reconstruction of the defect is planned preoperatively. In general, reconstruction is based on the concept of the reconstructive ladder. The methods of reconstruction are ranked by complexity; most descriptions of the reconstructive ladder start with closure by secondary intention, primary closure, local flaps, regional pedicled flaps, and microvascular free flaps. In the current patient, the surgical defect after resection would result in a significant loss of tissue, because oncologic clearance generally incorporates 1 to 1.5 cm for the margins and, depending on frozen sections, may incorporate another 3 to 5 mm circumferentially.

With respect to tongue defects, reconstruction should consider preserving the patient’s functions of speech and swallow. Resections incorporating the anterior tongue require the tongue tip for articulation and for propelling a food bolus posteriorly; the posterior tongue is largely involved with swallowing. Primary closure is an acceptable means of reconstruction if closure will not restrict tongue mobility. For the current patient, the radial forearm free flap was selected to provide bulk and to prevent restriction in tongue mobility that would affect speech and swallowing functions. Because tongue defects vary, a variety of free flaps can be used to restore form and function. When a glossectomy leaves more than 33% to 50% of the tongue, emphasis should be placed on maintaining mobility of the remaining tongue through the use of a thin, pliable flap, such as a radial or an ulnar fasciocutaneous free flap. When the defect leaves less than 33% of the original tongue, reconstruction shifts to the restoration of bulk to direct secretions toward the oropharynx and to provide contact of the neotongue with the palate for deglutition. For greater tissue bulk, the anterior lateral thigh free flap is an effective choice for reconstruction.

The radial forearm fasciocutaneous flap is the soft tissue flap of choice for reconstructing small to medium-sized oral and oropharyngeal defects. Based on the radial artery and cephalic vein and/or venae comitantes, it consists of thin, pliable skin and a very long pedicle, which make it well suited for use in the oral cavity. It can be designed to include tendons, muscle, or a segment of bone up to 12 cm in length, making it also useful for composite maxillary and mandibular defects.

The current patient was placed under general anesthesia and underwent a tracheostomy to secure his airway. A marking pen was used to delineate the planned resection edges, and a paper template was used to approximate the size and shape of the resection. A left hemiglossectomy was performed, and the margins of the resection were confirmed to be adequate with frozen sections (Figure 12-6, A and B).

A left selective neck dissection was performed to sample lymph nodes from levels I through III and to expose and preserve vessels for microvascular reconstruction (Figure 12-6, C). These vessels included the internal jugular vein and the internal and external carotid arteries and their associated branches.

Simultaneous harvest of the radial forearm free flap was performed on the nondominant hand (Figure 12-6, D). The template was used to approximate the area of skin needed for the fasciocutaneous flap harvest. Generally, the skin of the entire volar forearm may be harvested, extending from the antecubital fossae to the flexor crease of the wrist. The skin and subcutaneous tissue are thinner in the distal forearm than in the proximal portion of the forearm. Also of note, the area of the distal forearm is thinner in males than in females.

Clinical landmarks that assist in the harvest of a radial forearm free flap include the distal extent of the flap within a flexor crease of the wrist, the antecubital fossae, and the brachioradialis, flexor carpi radialis, and palmaris longus, in addition to the outline of the planned flap. The flap is centered to overlap the region of the vascular pedicle located between the brachioradialis and flexor carpi radialis (Figure 12-6, E).

In the current patient, a tourniquet was placed proximal to the elbow and inflated to 250 mm Hg to facilitate dissection. An incision was made along the distal margin of the planned flap to expose and identify the vascular pedicle, cephalic vein, and superficial branch of the radial nerve. (After identification of the vascular pedicle, a confirmatory Allen’s test can be performed with a bulldog clamp, the tourniquet let down and perfusion checked in the hand. A subfascial dissection is completed to the extent of the planned flap, with care taken to incorporate the vascular pedicle and to travel along the brachioradialis and flexor carpi radialis and to incorporate the cephalic vein. At the proximal margin of the flap, the vascular pedicle is dissected free to the antebrachial fossae. Along the medial aspect of the skin flap, care is taken to avoid injury to the ulnar artery during dissection [deep between the flexor digitorum superficialis and flexor carpi ulnaris muscles.])

The radial artery was clamped and divided at its most proximal extent at the branching of the brachial artery to form the radial and ulnar arteries. (The cephalic vein is generally dissected free into the antebrachial fossae. The superficial branch of the radial nerve of the forearm runs with the radial artery beneath the distal belly of the brachioradialis. At approximately the midpoint of the brachioradialis, the nerve continues laterally and the radial artery courses medially. For this reason, it is often not included in the raised pedicle; therefore, the antebrachial cutaneous nerve is relied upon to supply the paddle.)

Once the radial forearm flap had been harvested, it was inset into the intraoral defect (Figure 12-6, F). Because of the vessel geometry, the pedicle was delivered medial to the left mandibular body and placed alongside the great vessels of the neck. Excess skin was removed to achieve the desired bulk, and the flap was secured to the resection wound edge prior to the microvascular vessel anastomosis. The term “ischemia time of the flap” refers to the time from harvesting of the flap to the moment the artery is reestablished. Free flap reconstructions require a period of tolerance to tissue ischemia. Studies have demonstrated that this period of tolerance varies with the tissue type. Most flaps incorporate skin, fascia, muscle, and bone tissue. Skin and fascia are the most resistant to ischemia; they have a tolerance period of 4 to 6 hours before irreversible cellular injury occurs that could jeopardize the viability of the free flap. Muscle is generally the most sensitive to ischemia time; it has a tolerance period of less than 3 hours.

In the current patient, after flap harvest, the tourniquet was released, hemostasis was confirmed, and a split-thickness skin graft was harvested from the left thigh and grafted to the radial forearm free flap donor site. The arterial anastomosis was performed in an end-to-end fashion into the facial artery with 9-0 nylon sutures in an interrupted fashion, and the venous anastomosis was performed in an end-to-side fashion into the internal jugular vein. (During the microvascular anastomosis, heparinized saline [100 µ/ml] is used to mute the process of thrombosis in the lumen of the vessels. Inherent to the anatomy of blood vessels, arteries generally have a thicker media, whereas veins have thinner vessel walls; hence, anastomosis for the artery is commonly completed with sutures, and the veins are coupled together, because their thin walls make them amenable to coupling.) Adequate perfusion of the flap was confirmed clinically by assessment of color, texture, capillary refill, and temperature. (Doppler probes are also regularly used to assess blood flow through the free flap.)

Closure of the donor site was completed in a layered fashion, with dermal sutures followed by staples for the skin. The skin paddle donor site can be closed primarily if it is small, and techniques have been described for using local flaps (Z-plasty) to facilitate closure. Most defects are repaired with either a split-thickness or full-thickness skin graft. Unlike microvascular flaps, these grafts are dependent on nutrition from the recipient bed via plasmatic circulation or imbibition for 48 to 72 hours, until capillary in-growth occurs. During the initial wound healing phase, it is necessary to bolster the graft on the recipient bed to provide stability for the healing process. The split-thickness skin graft incorporates the layers of the epidermis and a portion of the dermis. Its advantages include the ability to cover large areas with a higher rate of successful graft take. On the other hand, split-thickness skin grafts are less esthetic, are susceptible to more contracture, and require an additional donor site. Full-thickness skin grafts incorporate layers of the epidermis and dermis and provide a more esthetic result with less late wound contracture. The donor site for the full-thickness skin graft can also be closed primarily, and the graft can be harvested from inconspicuous areas of the body, such as the supraclavicular area or, more commonly, the medial aspect of the upper arm.

In the current patient, the harvested split-thickness skin graft was bolstered with a wound vacuum-assisted closure system, and the wrist was immobilized for 5 to 7 days with a volar splint to prevent shearing of the skin graft. The flap remained viable at the recipient site and healed without complications.

Complications

The surgical complication rate among patients undergoing microvascular reconstruction after head and neck surgery is 19% to 22%. The majority of these surgical complications are related to the reconstructive effort and manifest as flap loss, partial loss, and wound healing complications at either the donor or recipient site. Preoperative risk factors that have been described to contribute to the incidence of surgical complications include American Society of Anesthesiologists (ASA) status of III or IV, low preoperative hemoglobin, prolonged operative time (longer than 10 hours), and prior radiation and/or surgery. Factors specific for free flap failure have been associated with the surgeon’s experience, flap selection, and the patient’s nutritional status. Free flap failure rates have improved significantly since this technique moved into mainstream use. Initial free flap survival rates, during the first decade of popularity in the 1980s, ranged from 85% to 89%; recent studies show that they have improved to more than 95%. A review of 248 consecutive microvascular free flap reconstructions at Legacy Emanuel Hospital in Portland, Oregon, found a 95.5% success rate. The radial forearm fasciocutaneous free flap was used in 52% of cases, reflecting its popularity for reconstruction of defects in the oral cavity. Specifically, the radial forearm free flap demonstrated excellent success, with flap survival rates of 96% to 100% in multiple studies.

The main disadvantage of the radial forearm fasciocutaneous free flap is the morbidity associated with the donor site. Inherent to the harvest of the graft is the manipulation of the superficial branch of the radial nerve, because this nerve is closely associated with the cephalic vein. The superficial branch of the radial nerve provides sensory input for the dorsal surface of the thumb and the second and third digits. Abnormal sensation (hypoesthesia, hypesthesia, or paresthesia) in the donor hand occurred in 82% of patients at 3 months after surgery; however, this improved to 26% during a mean follow-up period of 14 months.

Wound healing accounts for most of the complications associated with the donor site. Subfascial radial forearm fasciocutaneous free flap harvests demonstrated a higher incidence of skin graft loss, ranging from 16% to 28%; in this same subgroup, tendon exposure and delayed healing accounted for 13% to 28% and 22% to 28%, respectively. An alternative to harvesting of the radial forearm free flap involves suprafascial dissection, which tends to leave the exposed tendons of the forearm with investing fascia and some deep subcutaneous tissue to allow for a better foundation for the split-thickness or full-thickness graft. Skin graft losses in suprafascial donor sites are reported to be 4% to 6%. The incidence of skin graft loss has been associated with the likelihood of decreased grip strength. It is reported that subjective grip strength was significantly decreased in 5% to 10% of patients who demonstrated partial skin graft failure.

Use of the radial forearm flap as an osteocutaneous flap can be associated with the risk of radial fracture. A segment of vascularized bone can be harvested, and the length is limited by the attachments of the pronator teres muscle proximally and the brachioradialis muscle distally. On average, 10 to 12 cm in length and less than half of the radius can be harvested. Prophylactic plating of the radius is recommended to decrease the likelihood of radius fracture. Prior studies in which the radius was not plated after harvesting reported a fracture incidence of 15% to 67% in donor arms.

Discussion

Since the original description of the radial forearm fasciocutaneous free flap, more than 30 years ago, this technique has evolved into a versatile and reliable flap for head and neck reconstruction. First described by Taylor in 1976 and publicized in oral cavity reconstruction by Soutar and colleagues in 1983, this flap continues to be a popular soft tissue flap despite the challenges with donor site morbidity. Alternative flaps, such as the cutaneous lateral arm flap, fasciocutaneous ulnar flap, and anterior lateral thigh perforator flap, have limited advantages, which focus on less donor site morbidity.

There are many applications for the radial forearm free flap in head and neck reconstruction. As demonstrated in this case presentation, tongue reconstruction with the radial forearm free flap is a common indication. Use of this type of flap has been described for reconstructing the ablative defects of the soft palate and mandible, restoring soft tissue deficiencies, and repairing tracheoesophageal fistulas. Dual skin flaps have been used to reconstruct through-and-through defects in the cheek and lip, and with two-stage procedures, prefabricated grafts can be prepared for reconstruction of complex structures such as the nose (Figure 12-7).

The surgical anatomy of the radial forearm flap is consistent and readily assessed. As previously mentioned, the viability of a donor site is based on the results of Allen’s test. The blood supply is based on the radial artery, which is reliably found between the brachioradialis and flexor carpi radialis. On average, the length of the radial artery, from the antecubital fossa to the wrist, is 18 to 20 cm, and the vessel has a diameter of 2 to 2.5 mm. It is relatively superficial, and dissection is completed within a subfascial plane guided by the brachioradialis and flexor carpi radialis. The radial artery is intimately associated with the overlying fascia and supplies perforating vessels that pass through to form subfascial, intrafascial, and suprafascial vascular plexuses. These networks establish the extensive subcutaneous vascular plexuses that supply the skin. The fascia provides a degree of additional protection to the pedicle and overall integrity of the flap.

Multiple variations of this flap can be developed from the incorporation of accessible anatomic resources. Additional bulk can be obtained from the brachioradialis, tendon and ligaments can be obtained from the palmaris longus when necessary, and innervation through the antebrachial cutaneous nerve and bone can be obtained through harvest of the radius.

Venous return for the free forearm flap is classified as a deep and superficial venous supply. The deep supply is composed of the venae comitantes, which run in the intermuscular septum along with the radial artery. The superficial venous supply consists chiefly of the cephalic vein. Both systems provide venous outflow for the tissue supplied by the radial artery. The harvest of both venous systems allows for anastomosis of two veins. A study of 492 head and neck free flap procedures performed at the University of Toronto compared two-vein anastomosis with single-vein anastomosis and demonstrated an improved success rate for the former (98.6% versus 93.6%). This finding was also illustrated in an evaluation of microvascular couplers in head and neck reconstruction; in this study, dual vein–coupled anastomosis showed a trend for improved success over single vein–coupled anastomosis. When only a single vein is used for reconstruction, there are no differences in using the superficial over the deep venous system as the sole outflow for the flap.

In a vessel-depleted neck, a radial forearm hybrid flap can be used to compensate for the lack of vascular options. This scenario is most common in previously operated and irradiated fields. The radial forearm hybrid flap uses a single arterial anastomosis that is carried out between the radial artery of the flap and a recipient artery and the venous drainage (the cephalic vein), to remain in continuity with the systemic venous system. Technically, the cephalic vein is dissected up to the deltopectoral groove, pedicled over the clavicle, and delivered into the neck in the subcutaneous plane.

The radius is situated lateral to the ulna and articulates with the humerus and ulna proximally and with the ulna, scaphoid, and lunate bones distally. It averages 23 cm in length and in cross section the radial shaft appears triangular. Functionally the radius plays a minor role in the stability of the elbow; however, at the radiocarpal joint, it is an integral structure of the wrist. The proximal head of the radius allows the hand to pronate, and the distal head plays a role in hand flexion, extension, adduction, and abduction.

The brachioradialis functions to flex the arm at the elbow and for pronation and supination of the forearm. Its origin is at the lateral supracondylar ridge of the humerus, and it attaches to the distal styloid process of the radius by way of the brachioradialis tendon. It is located in the posterior compartment of the forearm and is innervated by the radial nerve. In reconstruction, the brachioradialis can be used to provide bulk, such as in a total glossectomy defect.

The skin available to be harvested on the forearm is defined by the radial artery angiosome. It extends from the flexor crease of the wrist to the antecubital fossa and from the medial third of the ventral surface of the forearm to the lateral third of the dorsal surface of the forearm. If an innervated flap is considered, the somatosome of the lateral antebrachial cutaneous nerve is used to guide the location of skin flap harvesting. The somatosome of the lateral antebrachial cutaneous nerve extends from the midline of the ventral forearm to the lateral third of the dorsal surface of the forearm.

Innervated tongue flaps are accomplished by neurorrhaphy of the lateral antebrachial cutaneous nerve to a recipient nerve. Sensation recovery of the innervated radial for/>