Complications of Myocutaneous and Local Flaps
Every head and neck surgeon will encounter situations in which a primary closure will be inadequate. In these situations, local or pedicled myocutaneous flaps can be an excellent choice for coverage of these defects. When done properly, these types of flaps have an excellent success rate. This chapter will focus on the complications of local and pedicled flaps, how to avoid them, and what to do if they happen.
Complications of Pedicled Myocutaneous Flaps
Despite the widespread use of microvascular reconstruction with free flaps, pedicled flaps are still important tools in head and neck reconstruction. These flaps are reliable and do not require the specialized postoperative care needed for free flaps. In general, these flaps can have complications with the donor and/or recipient site. Donor site complications include hematoma, seroma, and infection. Recipient site complications include partial or total flap loss, hematoma, seroma, infection, dehiscence, and fistula formation. Two pedicled flaps will be considered: the pectoralis major myocutaneous flap and the latissimus dorsi myocutaneous flap.
Pectoralis Major Myocutaneous Flap
The best opportunity to avoid complications is when designing the flap.
Since Ariyan1 described the use of the pectoralis major flap in the use of head and neck defects in 1979, it has remained an essential procedure in the head and neck surgeon′s armamentarium. Four recent studies were reviewed for a total of 1,251 patients. The overall complication rate was 32.4%, including the donor and recipient sites. This seemingly high rate of complications is tempered by the fact that the incidence of total flap loss ranged from only 1% to 4%. Donor site complications ranged from 1 to 5.3% and included necrosis, hematoma, infection, and seroma. Recipient site complications were reported in 9.5 to 29.7% of patients and involved dehiscence, fistula, partial or total flap loss, infection, or neck contracture. Radiation has been associated with an increased risk of complications.2–5
The best opportunity to avoid complications is when designing the flap. A simple skin pinch test can help to determine the maximum width of the skin paddle to avoid an overly tense closure at the donor site. Also, one should consider the amount of subcutaneous tissue between the skin paddle and muscle, as increased bulk in this area can compromise the health of the skin. This is especially an important consideration in women with large amounts of intervening breast tissue. If the flap is too bulky, then one should consider another flap. Keeping the skin paddle entirely over the pectoralis muscle, not extending the skin over the rectus abdominis, and beveling out from the skin to capture more muscle are all techniques to improve the number of perforator vessels to the skin paddle.6
Hematomas at the donor site can be avoided by meticulous attention to hemostasis before closing. Infection at the donor site is likely caused by cross-contamination from saliva at the primary tumor site. If there is any concern, the donor site should be copiously irrigated before closure. To avoid seromas, we routinely place two drains at the donor site: one at the lateral edge and one at the inferior edge. In this way, the gravity-dependent drainage will be captured both while sitting up and when in the recumbent position.
Fistula formation and dehiscence can be a result of a variety of factors such as poor nutrition, previous radiotherapy, and diabetes. Another factor is excessive tension or bulk. We avoid “tubing” a pectoralis flap because its excessive bulk is detrimental to the closure. Instead, if a total pharyngectomy defect is encountered and a free flap cannot be used, then the pectoralis flap will be sutured directly to the prevertebral fascia. Dehiscence can be avoided by designing a paddle with adequate length. It should be kept in mind that length will be lost during the rotation of the flap from the chest to the head/neck, and this must be accounted for.
Ischemia or venous congestion leading to total loss of the flap is rare but can be avoided by ensuring that there is no compression of the pedicle ( Fig. 28.1 ). The flap should be brought through a subcutaneous tunnel, external to the clavicle, with at least four fingerbreadths of room. If there is too much tension still, as in previously irradiated patients, then the pedicle and surrounding muscle can be exteriorized and skin can be grafted. If ischemia is discovered in time (within 4 hours) it is best to re-explore. Venous congestion can be treated with medicinal leeches.7 Another consideration is to remove some of the sutures at the recipient site.
A particularly difficult to treat but rare complication of pectoralis major flaps is costal osteomyelitis or necrosis. During the raising of the pectoral muscle off the ribs, one should take care to not apply cautery directly to the ribs. Conservative treatment involves appropriate antibiotic coverage.8
The latissimus dorsi pedicled myocutaneous flap offers a sizable skin paddle and bulk for large head and neck defects.
One of the main drawbacks of a latissimus dorsi pedicled myocutaneous flap is that it is difficult to raise concurrently with the primary tumor resection. The pedicle is also somewhat prone to kinking and so is not quite as reliable as a pectoralis flap, even in experienced hands.
In the recent literature, total flap loss ranges from 1 to 10%. The rate of any complication, major or minor, is 10 to 35%. Donor site complications include dehiscence, seroma, and hematoma. Recipient site complications include dehiscence, infection, hematoma, partial/total flap loss, and fistula.9–13 Brachial plexus injuries were reported early in the experience of this flap and are likely to be the result of positioning and hyperadduction of the arm.14
Whereas earlier studies did not find significant shoulder weakness after flap transfer, more recent papers have detected some disability in a significant number of patients. Adams and Lassen7 found that 39% of patients complained of at least moderate weakness. Another study identified six of 18 patients who were limited in their ability to carry out housework.15–17 Shoulder dysfunction can be minimized by not performing a concurrent pectoralis major myocutaneous flap on the ipsilateral side, or if that side already has spinal accessory nerve palsy.
As stated before, the vascular pedicle is prone to kinking at the site of tunneling. The pedicle can be tunneled between the pectoralis minor and pectoralis major or between the clavicle and skin. If there is excessive tension, an incision between the clavicle and recipient site can incorporate the proximal skin paddle. In one study, all 15 flaps recorded were successfully transferred via a subscapular tunnel (between the scapula and clavicle) and brought out into the posterior triangle.18 Hayden et al12 recommend preserving the circumflex scapular branches to “maintain a gentle curve of the vascular pedicle.” They also advise preserving the humeral tendon until the pedicle dissection and tunnel are complete, to protect against excessive traction.