Reconstructive Surgery: Pedicled and Free Visceral Flaps
Pedicled or free visceral flaps are used in the reconstruction of pharyngolaryngeal and esophageal defects. They are an alternative to reconstruct defects limited to the pharynx or the cervical esophagus microvascular fasciocutaneous free flaps; however, their use is mandatory in extensive defects including those of the thoracic esophagus.
Reconstruction of circumferential defects limited to pharyngolaryngeal and cervical esophagus is accomplished by means of jejunum free flaps ( Figs. 30.1 and 30.2 ). The gastric pull-up is indicated when a thoracic esophagectomy is necessary ( Figs. 30.3 and 30.4 ). For patients in whom a gastric pull-up is not an option because of previous gastric surgery, or in very extensive tumors invading up to the oropharynx, a free colon transfer or pedicled colon interposition, with or without vascular supercharge, is the second best option. If neither the stomach nor the colon flaps are feasible options, then a long jejunal segment with two vascular pedicles is the next alternative.
Salvage reconstruction of the esophagus after failure of a gastric pull-up is still considered a challenging procedure because of its associated risks of postoperative infection and delayed wound healing, as well as the unavailability of recipient vessels for free tissue transfer. In these patients a free jejunal transfer including two long segment transfers with double vascular pedicle or colon interposition with vascular supercharge can be performed. Total esophageal reconstruction with supercharged pedicled jejunum has also been proposed as an alternative in patients receiving a total resection of the esophagus.
In general terms, the surgeon must possess a reconstructive algorithm that progresses according to the defect, the available donor sites, and surgical experience.
Jejunal Free Flaps
Postoperative complications, including those considered minor or not related to the graft, are frequently encountered, and occur in up to 80% of patients ( Table 30.1 ). In a series of 79 free jejunal transfers, medical complications and complications at the recipient and donor sites occurred in 67%, 56%, and 11%, respectively.1 Rates of major complications ranged between 7 and 20%, including death and total flap failure. Minor complication rates ranged between 25 and 45%. To achieve a more objective and accurate evaluation of postoperative morbidity, it has been recommended to stratify postoperative complications according to a standard classification (i.e., Clavien–Dindo2).
In general terms, mortality after a jejunal free flap is rare, and occurs in less than 5% of patients; however, in some series it has been reported to be as high as 17%. Overall failure rate of jejunal free flaps is also low; a successful flap is attained in 90 to 100% of patients and most series show flap survival rates higher than 95%.
Oral bleeding is the most prominent sign of a failed flap; and, most flap failures occur within 2 weeks of surgery. Most failures are due to venous thrombosis, and in ~ 80% of cases thrombosis develops within 3 days after surgery ( Figs. 30.5 and 30.6 ). Sometimes this circulatory crisis can be restored with emergency exploration; however, most of these flaps do not survive because of the poor ischemic tolerance of the jejunum (mainly in cases of arterial thrombosis).
Flap failure is significantly more frequent in patients with a history of previous surgery and postoperative infection, but it also occurs as the result of inadequate microsurgical technique. After a complete loss of the jejunal flap, the risk of postoperative infection and delayed wound healing is high because of thick scar formation and persistent inflammation, and; furthermore, recipient vessels for free tissue transfer are not always available. Nevertheless, in most cases of flap failure the cervical esophagus is usually reconstructed with a second free jejunal transfer or with a fasciocutaneous free flap. Surgical options depend on time of detection of flap necrosis, control of wound bacterial count, vascular status, and the patient′s general conditions. A pectoralis major myocutaneous flap should be considered to cover the reconstructed esophagus, because it is a reliable technique and primary wound closure is often difficult during a secondary reconstruction of the cervical esophagus ( Fig. 30.7 ). When regional or general conditions do not permit further free flap transfer or when defects are comparatively small, reconstruction with a pedicled flap is a preferable option.
Postoperative pharyngocutaneous fistula is a common complication, that is observed in 5 to 30% of patients. Chang et al3 identified 13.7% of patients with fistulas in a series of 168 patients who underwent free jejunal transfers following total laryngopharyngectomy. In this series the mean onset of fistula formation was 16 days, with a similar frequency of fistulas occurring at the proximal and distal anastomoses. The incidence of fistula formation was highest in patients with a single-layer repair and in patients who received preoperative radiotherapy. Postradiotherapy fistulas, however, were mainly located at the distal anastomosis. Most of the fistulas closed spontaneously (65%), particularly at the proximal anastomosis in patients who had not been irradiated. Distal fistulas in patients who have been irradiated usually need surgical repair; therefore, the use of a “prophylactic” pedicled pectoralis major myofascial flap to prevent fistula formation in previously irradiated patients has been advocated.