Master Techniques in Otolaryngology - Head and Neck Surgery: Reconstructive Surgery, 1ed.

32. Radial Forearm Free Tissue Transfer

Brett A. Miles

INTRODUCTION

Surgical management of cancer of the hypopharynx, cervical esophagus, and larynx often results in defects in the cervical esophagus requiring reconstruction with free tissue transfer. Esophageal strictures requiring free tissue reconstruction are often a result of surgical and nonsurgical therapies for these malignancies. Patients with traumatic injuries and ingestion of caustic substances may rarely require esophageal reconstruction.

Perhaps the most challenging pharyngeal/cervical reconstruction is the free tissue transfer reconstruction of the cervical esophagus while maintaining an intact larynx. Previous surgery and radiation therapy often result in significant motor and sensory dysfunction of the cervical esophagus and larynx that is further complicated when reconstructive efforts are entertained.

Chronic aspiration, dysphagia, chondroradionecrosis, and pain may result in a nonfunctional larynx as a result of nonsurgical organ preservation strategies. In many such cases, total laryngectomy may be indicated despite a successful oncologic outcome of the initial treatment. Perhaps the least appreciated aspect regarding this patient population is the fact that resection of the cervical esophagus and successful free tissue reconstruction establishing a patent conduit does not always lead to successful swallowing outcomes. This is especially relevant in the context of adjuvant radiotherapy.

A variety of esophageal reconstructive options exist in the management of total laryngectomy, including gastric transposition, pectoralis major myocutaneous flap, jejunal flap, colonic interposition, anterolateral thigh flap, and the radial forearm flap. When the larynx is intact, a thin and well-vascularized flap is essential for reconstructing an isolated defect in the cervical esophagus in order to maximize functional outcome and provide reliable healing for the esophageal conduit. The radial forearm free tissue transfer offers several advantages in this situation including thin, well-vascularized tissue that conforms to the defect and has an extremely reliable vascular pedicle. The technique of esophageal reconstruction with the radial forearm free tissue transfer is reviewed.

In general, the presenting history of a patient requiring esophageal reconstruction is relatively straightforward. Dysphagia, regurgitation, aspiration, odynophagia, or complete inability to tolerate oral intake are common complaints in patients with malignancy and/or stenosis/stricture from a variety of etiologies as noted above. Any historical insult to the cervical esophagus may be relevant in these patients including surgery, radiation, caustic ingestion, and trauma and should be considered by the surgeon prior to selecting the best reconstructive technique.

While the physical examination of patients requiring cervical esophageal reconstruction may be normal, findings such as masses in the neck, cervical fistula, pain, and soft tissue fibrosis/scarring may be present and should be evaluated by the surgeon. Mobility of the tongue and soft palate should be documented in order to identify factors contributing to the dysphagia. Flexible fiberoptic examination should be performed to evaluate the postcricoid space, laryngeal structures, epiglottis, and the base of the tongue. The sensation of the larynx should be tested and documented. The patient should be asked to swallow, and observation of the mobility of the tongue and pharynx, mucosal surface hydration, laryngeal elevation, and aspiration/coughing should be noted. More formal swallowing evaluation should be used in the majority of cases as noted below.

Indications for esophageal reconstruction vary and are listed below. The most common indications are cancers of the upper aerodigestive tract and thyroid. Sequelae from the treatment of these lesions such as surgery and radiation resulting in stricture or fistulae are common indications. Congenital anomalies requiring free tissue transfer are relatively rare. Functional abnormalities such as perforated Zenker diverticula, achalasia, or other esophageal abnormalities occasionally require more advanced reconstruction after failure of previous therapy.

• Cancer of the esophagus

• Cancer of the larynx or thyroid with invasion of the esophagus

• Caustic ingestion/chemical injury

• Esophageal stricture

• Cervicoesophageal fistulae

• Traumatic injuries

• Congenital abnormalities

• Functional abnormalities

There are no specific contraindications to cervical esophageal reconstruction. General medical conditions may prohibit reconstructive efforts; however, in most patients, reconstruction of the cervical esophagus can be performed. In the event that thoracic or abdominal access is required for reconstruction, the risk profile as well as the associated contraindications change. Candidates with complicated prior abdominal/thoracic surgery may not be candidates for gastric pull-up or thoracic access for esophageal reconstruction. An obvious contraindication for radial forearm free tissue transfer is inadequate ulnar arterial flow as evaluated by a preoperative Allen test or ultrasonographic vascular studies of the upper extremity. In these situations, another reconstructive option such as the jejunum or anterolateral thigh flap is used.

The underlying etiology resulting in esophageal compromise often drives the preoperative evaluation in patients undergoing radial forearm free tissue transfer for esophageal reconstruction. Nevertheless, several considerations merit mention.

Anatomy

While the anatomy pertinent to esophageal reconstruction is beyond the scope of this chapter, several anatomical considerations are pertinent to reconstruction in this area. Perhaps the most important factor is body habitus in terms of technical difficulty. Overweight/obese patients are significantly more challenging and may require additional incisions and early thoracic access when compared to thinner patients. The surgeon should assess the distance between the mandible and the clavicle preoperatively to determine the relative working area and plan for surgical access accordingly. Patients with a previous history of cervical surgery, or injury, or range-of-motion limitations from kyphosis or secondary to radiotherapy are significant challenges. In these patients, mobilization of the distal esophagus may be problematic, and preemptive thoracic consultation is warranted in the event that reconstruction is not feasible without a combined approach.

In terms of the radial forearm donor site, the most important anatomical consideration is the preoperative Allen test, which is used to evaluate the vascular integrity of the palmar arch to ensure adequate blood supply to the hand after radial arterial harvest. In the event that the Allen test is questionable, an ultrasound flow Doppler Allen should be performed. Previous injury or surgery to the upper extremity may preclude the use of the radial forearm harvest.

Imaging Studies

The imaging studies required for successful esophageal reconstruction vary depending on the situation; however, in general, computed tomography (CT) with contrast enhancement is relatively standard. In addition, traditional esophagram will provide information regarding the anatomy of the lumen, which is not readily appreciable on CT scans. The esophagram will provide an accurate assessment of the length of the esophagus involved with the pathologic process to allow for reconstructive planning. This is especially true for patients with an esophageal stricture. Additionally, information regarding preoperative aspiration in patients who have undergone previous adjuvant therapies or surgery will be assessed, which is critical when preservation of the larynx is entertained. Modified barium esophagram is critical if preoperative swallowing dysfunction or aspiration is present, which is often the case, in order to determine the presurgical dysfunction and better determine the likely postoperative outcome. Somewhat less frequently MRI may be employed in cases where prevertebral soft tissue involvement with malignancy is suspected or other information related to the soft tissue is required.

Laryngoscopy/Endoscopy

It is difficult to overstate the importance of preoperative endoscopy in the evaluation of the cervical esophagus prior to embarking on resection and reconstruction. Functional evaluation of the motor and sensory components of the larynx is critical, if the larynx is to be preserved. Severe sensory or motor deficits and/or anatomical deficits due to previous surgery are contraindications to laryngeal preservation in conjunction with esophageal reconstruction due to functional disturbances and aspiration. In these situations, laryngectomy is often indicated. In addition, the length and magnitude of the stricture or pathologic process must be adequately evaluated prior to surgery.

Rigid and flexible esophagoscopy offer vital information for surgical planning and allow the surgeon to anticipate problems prior to surgery. Occasionally, retrograde esophagoscopy is required via a gastrotomy tube to adequately determine the existing anatomy. Problems such as thoracic involvement limiting access for esophageal anastomosis or extremely long strictures requiring gastric mobilization must be identified prior to surgery for appropriate planning.

The transcervical approach to the cervical esophagus is relatively well described and similar to preparation for laryngectomy. Subplatysmal flaps are raised to the level of the hyoid bone superiorly and inferiorly to the level of the sternum and clavicles. The sternocleidomastoid muscles are exposed. The structures of the carotid sheath must be identified and protected prior to reconstruction of the cervical esophagus. The extent of the dissection varies depending on the location of the proposed reconstruction; however, it is advisable to widely prepare the site as the bulk of the radial forearm flap and its associated vascular pedicle require adequate access for esophageal/pharyngeal anastomosis. In patients in whom laryngeal preservation is warranted, the larynx must be rolled laterally to expose the esophagus. Placement of a nasogastric tube early in the operation (when possible) will allow for identification of the esophagus and avoid inadvertent injury. Removal of the thyroid lobe on the ipsilateral side may be required to create room for the reconstruction and also allows for preparation of the superior thyroid vessels for microvascular anastomosis. The parathyroid glands are preserved if possible. Identification and preservation of the recurrent laryngeal nerve on the side of the reconstruction are necessary to preserve the swallowing function for the patient and prevent postoperative aspiration. Similarly, the superior laryngeal nerves should be preserved if possible. When the esophagus has been separated from the trachea, and the carotid structures are lateralized, the stenotic segment may be resected. Careful attention to the dissection inferiorly is required to avoid compromising the vascular supply of the distal cervical esophagus, which will be used for the neoesophageal anastomosis. In oncologic cases, the resection of the cancer with negative margins dictates the approach and extent of the resection. The defect can then be evaluated, and the reconstruction can be planned.

The harvest of the radial forearm free tissue transfer has been well described and is currently a very popular method of reconstruction of structures in the head and neck. Briefly, the flap is designed over the radial surface of the flexor surface of the forearm with the appropriate size measured from the defect. The distal portion of the incision should be approximately 1 cm proximal to the wrist crease, and the flap should include the cephalic vein if possible. Under tourniquet, the skin and dermis is incised and the cephalic vein, lateral antebrachial cutaneous nerve, and brachioradialis tendon are identified on the radial side of the flap. The ulnar artery lies medial to the flexor carpi ulnaris and lateral to the palmaris tendon, and preservation of the overlying fascia is mandatory to avoid inadvertent injury of the ulnar artery. The dissection in either a subfascial or suprafascial plane from lateral to medial to isolate the radial artery pedicle and the fasciocutaneous flap. At this point, the radial artery can be ligated distally after division of the extensor retinaculum and identification of the artery and its associated venae comitantes. Dissection of the vascular pedicle is then performed from a distal to proximal direction with the radial artery located between the brachioradialis muscle and flexor carpi radialis muscle. The proximal limit of the dissection is the antecubital fossa where the radial artery joins the brachial artery and the superficial cephalic/median cubital vein joins the deep venous system. At this point, the tourniquet can be released and flap perfusion verified. Perfusion of the distal extremity must be verified at this point in the event that vascular compromise is present requiring repair of the radial artery and aborting the flap procedure.

At the conclusion of the harvest, the radial forearm flap is inset into the esophageal defect (Figs. 32.1 and 32.2). In partial defects it is best to close the distal and proximal portions of the reconstruction and leave the central portion to close last for greatest access during closure. Additionally, insetting with a small triangle of flap into the distal esophagus may prevent stricture formation (see Fig. 32.3, Complications).

FIGURE 32.1 After laryngectomy. Note anastomosis suture lines may be oriented anteriorly or posteriorly, as long as potential leak areas are away from the vascular pedicle.

FIGURE 32.2 Radial forearm flap sutured in tubed technique (salivary bypass tube may be used, unless larynx remains intact).

FIGURE 32.3 A. Standard circumferential inset may result in contraction and stricture proximally and distally. B. Dart modification for stricture prevention. C. Oblique/twisted flap orientation, with dart modification. D. Running Z-plasty/triple dart type modification.

Postoperative care of the patient is relatively straightforward with standard flap monitoring protocols using the Doppler pen, and an external skin paddle if used. The duration of NPO status varies depending on the patient and reconstruction with longer periods indicated on a patient with a history of preoperative radiotherapy. Approximately 7 to 10 days is generally appropriate prior to obtaining a postoperative esophagram to verify that there is no anastomotic leak. If negative, a clear liquid diet may be instituted and advanced as tolerated to a soft diet. The nasogastric tube may now be removed.

The most devastating complications of esophageal reconstruction with the radial forearm free tissue transfer include complete flap loss secondary to vascular thrombosis, salivary fistula, hematoma, and infection, all of which may lead to a prolonged postoperative course. The risk of salivary fistula with radial forearm reconstruction is approximately 15% to 20%. Risk factors vary; however, previous radiotherapy is statistically correlated with fistula formation and increases the risk in pharyngeal/esophageal reconstructions. Preventative measures such as fibrin glue have been described with positive results but remain unproven as a reliable way to prevent salivary leakage. Positioning the longitudinal suture line posteriorly in contact with the prevertebral fascia has also been advocated. Conservative local management including packing/diversion and antibiotics are effective in approximately 60% to 65% of cases with the remaining requiring surgical revision and additional reconstruction. Regarding the location of the fistula, it appears that fistula occurring in the longitudinal portion of the anastomosis (partial reconstructions) is less common than distal/proximal fistula formation, which occurs at a rate of approximately 50%, respectively. Use of a salivary bypass tube may reduce the incidence of salivary fistula. Early exteriorization and local wound care are warranted to prevent additional complications.

Another potential complication, which is often challenging to manage, is postoperative stricture formation. The presence of a stricture is usually related to the occurrence of a salivary fistula. Some authors have advocated the use of alternative flaps for cervical reconstruction to avoid additional suture lines and stricture formation, while others prefer the radial forearm flap for its previously noted advantages. Technical recommendations include a small dart or angled interdigitation techniques, which may decrease the stricture rate when compared to circumferential anastomotic techniques (Fig. 32.3). Early recognition and management of postsurgical strictures may prevent failure of the reconstruction. Esophageal dilations should be initiated as soon as possible after initial healing (approximately 3 to 4 weeks), and serial dilations may be required.

The results after esophageal reconstruction often relate to the initial indication for the reconstruction. Primary resection of the esophagus with reconstruction will often result in an adequate salivary conduit; however, the flap is insensate and without muscular contraction. Therefore, partial reconstructions may fare better than total esophageal reconstructions in terms of swallowing as some muscular contractions are preserved. In cases where surgery and radiotherapy are indicated, the rates of stricture, fistula, and swallowing dysfunction are increased. The risk of aspiration must be evaluated in cases which the reconstruction involves an intact larynx, especially if laryngeal dysfunction is present (i.e., cervical esophageal reconstruction for thyroid malignancy with associated vocal cord paralysis). This is especially relevant in patients with significant pulmonary disease. In general, most patients will be able to resume oral intake; however, in cases where significant swallowing dysfunction is present, long-term gastrostomy dependence may occur. This possibility should always be discussed with the patients preoperatively. Caustic ingestion results vary significantly depending on the severity and length of the injury.

• Preoperative education of the patient regarding realistic postoperative swallowing results is critical to success.

• Suprafascial or subfascial dissection of the radial forearm flap is feasible.

• A nasogastric tube should be used to help identify the esophagus in difficult situations such as prior surgery and/or radiotherapy

• Do an elective tracheostomy.

• Interdigitation of the esophageal anastomosis may prevent stricture formation.

• Meticulous anastomotic closure is required to prevent salivary leakage.

• Early recognition with exteriorization of a salivary fistula is critical to minimize complications.

• The radial flap has a superior ischemia time and decreased donor site morbidity when compared to enteric flap options.

• The radial flap has a long, reliable vascular pedicle of excellent diameter for microvascular anastomosis.

• Dissection of the radial artery performed superficial to the flexor retinaculum improves visualization of the distal vascular pedicle.

• Avoid violation of flexor retinaculum overlying the ulnar artery.

• Meticulous attention to vascular perforators to prevent postoperative hematoma.

• Verify distal extremity perfusion after tourniquet release prior to completing flap harvest.

• External skin paddle may be used for monitoring if desired.

• Improper preoperative evaluation of the esophageal segment requiring reconstruction is inadequate surgical planning and may result in a complication.

• Preservation of the larynx may not be possible in cases with multiple previous insults such as surgery and radiotherapy.

• Head and neck surgical tray

• Steven tenotomy scissors, curved 6 inch (15 cm) Baby Metzenbaum 5 1/4 inch (14 cm)

• DeBakey Straight 1.5 mm tip Petit-Point mosquito 7 1/8 inch curved Jarit Flat Tip Scissors 5 inch

• Jamison Scissors Curved 7 inch Jamison-Metz Scissors Curved 6 inch

• Semken Needle Forceps, carbide, delicate 6 inch

• Gerald Forceps 1 × 2 teeth

• Adson Forceps, toothed Delicate Allis Clamps 7 1/2 inch

• Petit-Point Mixter 7 1/4 inch Polar/Army Navy retractors Medium Clip Appliers

• Small Clip Appliers

• Bipolar Insulated 4 inch 0.5 mm tip Monopolar Cautery, insulated tip Kittner dissector sponges Microvascular instrumentation

SUGGESTED READING

Varvares MA, Cheney ML, Gliklich RE, et al. Use of the radial forearm fasciocutaneous free flap and Montgomery salivary bypass tube for pharyngoesophageal reconstruction. Head Neck 2000;22(5):463–468.

Marin VP, Yu P, Weber RS. Isolated cervical esophageal reconstruction for rare esophageal tumors. Head Neck 2006;28(9):856–860.

Stile FL, Sud V, Zhang F, et al. Reconstruction of long cervical esophageal defects with the radial forearm flap. J Craniofac Surg 2006;17(2):382–387.

Andrade P, Pehler SF, Baranano CF, et al. Fistula analysis after radial forearm free flap reconstruction of hypopharyngeal defects. Laryngoscope 2008;118(7):1157–1163.

Murray DJ, Novak CB, Neligan PC. Fasciocutaneous free flaps in pharyngolaryngo-oesophageal reconstruction: a critical review of the literature. J Plast Reconstr Aesthet Surg 2008;61(10):1148–1156.