27 Free Flap Reconstruction

Dimitrios P. Mastorakos and Joseph J. Disa

Major head and neck extirpative surgery is frequently followed by plastic surgery reconstructive procedures in an attempt to restore function, cover a vital structure, or improve cosmesis. This need becomes ever more pressing after a secondary procedure, even if during the first procedure no such need was appreciated.1–3 This makes reoperative head and neck surgery a formidable undertaking that demands coordination between the ablative and reconstructive teams. A multidisciplinary approach is crucial to the successful completion of such an undertaking. This chapter examines the reasons for free flap reconstruction, the timing and purposes of such surgery, the technical issues involved, and specific problems associated with it.

Reasons for Reconstruction

The return of a patient to the operating room (OR) after a head and neck procedure is usually due to recurrence of the original pathology or a complication of the previous treatment modalities.^2,3 A recurrence usually involves the suture lines around the previous resection or the tissues neighboring the previous reconstruction. It is associated with increasing induration or mass effect of the tissues near the previous pathology. As a result of a possible infiltration of previous reconstruction,⁴ by the time the resection is completed, the new defect is usually larger than the old one, while at the same time the previous reconstruction is, for the most part, resected.

A complication in this setting is usually the result of either radiation therapy^5,6 or the development of a fistula.⁷ The changes associated with radiation therapy usually involve all the tissues exposed to it, including bone and blood vessels.^8,9 This makes issues such as coverage of hardware and identification and dissection of recipient vessels for microanastomoses very challenging. Equally challenging from a different standpoint can be the management of a fistula. It is usually the result of a flap or a suture line failure and can result in probably the most feared of complications, namely, the carotid artery blowout.¹⁰ In such a situation, addressing the problem becomes rather pressing.⁷

Timing of Surgery

Because reoperative head and neck surgery is never a trivial undertaking, the timing of such a procedure can be very critical. Depending on the reason for the return to the OR, this can be done emergently, urgently, or at a later date. Emergency surgery is usually associated with massive bleeding or airway obstruction. The role of the reconstructive surgeon in this setting is to ensure coverage of sensitive structures, with living and well-vascularized tissue, once the bleeding or airway obstruction has been relieved.¹¹ This includes the revision of previous reconstructive solutions once hemostasis has been assured. Preventing such complications with reliable coverage of all vascular structures beforehand, prompt drainage of collections, and securing of a stable airway is always easier than salvage surgery in an emergency setting. Urgent management is usually associated with hardware or sensitive structure exposure, such as bone, vessels, or meninges. The approach here should be one of proactive management, trying to minimize the extent of damage caused. Lastly, late approaches are usually associated with radiation-induced changes, exposure of heavily irradiated or even necrotic tissue, or aesthetic shortcomings of the previous surgery outcome.

Purposes of Reoperation

The rationale behind returning to the OR for reoperative head and neck surgery is damage control, another attempt at curing the patient, palliation, or functional/cosmetic improvement. Keeping in mind the purposes of the surgery can be crucial because this could dictate the extent of resection, the sophistication of the reconstruction, and the length to which one is prepared to go to accomplish it.

Condition of the Patient

Evaluating the general medical condition of the patient is paramount before embarking on a lengthy and complicated reoperative endeavor.¹² Issues such as nutrition, tobacco or alcohol or even drug abuse, and history of chemotherapy or radiation, as well as the Acute Physiology and Chronic Health Evaluation (APACHE) II score,13 are extremely important when assessing the patient preoperatively. Virtually all patients have long histories of alcohol and/or tobacco abuse. A large number of them will be debilitated because of malnutrition secondary to the disease itself, other treatment modalities, or long-standing poor health.¹⁴ Pulmonary and cardiovascular assessment is always critical, as it was before the first procedure. Aspiration pneumonia, adult respiratory distress syndrome (ARDS), prolonged respiratory insufficiency or intensive care stay, stroke, and myocardial infarction are well-known complications after such surgeries. Actually, many would argue that even before the first procedure, one should evaluate the ability of a patient to go through reoperation.¹⁵ A negative answer should steer the reconstructive surgeon away from complex and lengthy reconstruction toward an expeditious and reliable procedure. It appears, therefore, that a reoperative approach is one of potentially significant morbidity and mortality, and this should be made clear to the patient beforehand.

One should always take into consideration the patient’s priorities and wishes.¹⁰ Oftentimes what the physician considers important will not coincide with the patient’s views. A better cosmetic outcome, for instance, might not be worth a prolonged stay in the hospital. Therefore, getting to know the patient’s views and needs and describing the functional, aesthetic, and structural defects anticipated can be very helpful in providing the best possible solution to the patient’s problem.

Approaching Reoperative Free Flap Surgery

When faced with a reoperative head and neck surgery, one should first try to visualize the defect present once the ablative surgeon has completed his or her part. The extent of soft tissue deficit, the bony structures missing, the neurovascular structures resected or ligated, and the functional deficit are all issues to be taken into consideration. To do that, one should be able to communicate fully and reliably with the ablative team preoperatively but also during the surgery itself, assessing or even modifying the defect while it is created. Preoperative imaging and a physical examination will help a great deal by allowing a fairly accurate estimate of the anticipated defect.

The next step is to take an inventory of all the possible reconstructive options available once the resection is completed. To that end, one should take into consideration the possible vascular and neural structures affected by the surgery, as this could determine the strength of particular surgical options. Local, regional, and distant flaps, simple and composite tissue reconstructions, single- or multiple-stage procedures, use of bone/nerve/vein/skin grafts, even the use of medical prosthetics, are all options to be considered. This decision process must also take into consideration the condition of the patient, and whether it would or would not allow some of these options.^14,16 Additionally, local conditions are crucial. By now most patients will have already been irradiated, and many of the locally present landmarks and planes will have been obscured. This raises the degree of difficulty associated with the dissection and makes the presence/condition of the structures dissected rather unpredictable.

Technical Issues

In the reoperative setting, one will obviously come across the stigmata of previous surgery, such as scar tissue, obscured tissue and fascial planes, and displaced and distorted anatomical relationships. Some of the native vessels would have been ligated or used during the earlier procedure. This setting, coupled with the fewer vessels available to the reconstructive surgeon, makes dissecting a reoperative neck and establishing recipient vessels for microvascular anastomoses formidable undertakings. Fine instruments, atraumatic blunt and sharp dissection, and a concerted effort to get out of the zone of injury are all ways to approach this challenge. The full extent of the reconstructive ladder, including classic and reliable options such as the deltopectoral or the forehead flap, all the way to free flaps and composite tissue transfers, should be considered.^17–19 The option best suited to the patient’s needs should be the one chosen, and age alone should not be considered a contraindication to free flap reconstruction.¹⁶

When microvascular tissue transfer is the procedure of choice, careful attention must be given to the perioperative management of the patient. Due to the long operative time and the complexity of the procedure, a multidisciplinary approach is warranted. Anesthesia, medicine, cardiology, intensive care, infectious diseases, nursing, and respiratory and physical therapy are all disciplines needed to come together to assist in getting the patient through the perioperative period.¹³ Careful positioning during surgery, prevention of hypothermia, invasive cardiovascular monitoring of patients with compromised cardiac or pulmonary function, and optimization of the fluid status become significant issues.

The Irradiated Neck

Particular attention is due to the irradiated neck. Aside from the inherent difficulty of redissecting a previously dissected neck due to scar tissue adhesions, the added fibrosis and friability of radiated tissue make the environment even more hostile.9 The vessels are usually incorporated in thick scar tissue, completely obscuring the anatomical planes.⁵ Judicious use of blunt dissection with fine-tipped instruments can be very helpful. In addition, particular attention should be given to the quality of the soft tissue and skin covering the vital neck structures. Any doubt of viability should prompt resurfacing with fresh, well-vascularized, and healthy soft tissue and skin.

Vascular Access

Obtaining vascular access should always be the first step toward a complex reconstruction in the neck.²⁰ Unless good quality vascular access has been established, one should avoid raising any kind of flap as a free tissue transfer. In addition, a fallback option of a local flap should always be in place, if possible, should the securing of a vascular access prove impossible. Helpful points include the following:

1. Going for major vessels with well-known and fairly constant anatomy (external carotid, lingual artery, common facial artery, superficial temporal artery) preferably outside the zone of injury/radiation

2. Minimal threshold before going to the opposite side or using the external carotid artery in an end-to-side fashion if the ipsilateral vascular access proves impossible

3. Avoiding vein grafts, if possible, and using flaps with long vascular leashes

4. Unless a perfect match to the donor vessels is found, preferring the internal jugular vein (IJV) with its optimal sump flow characteristics to any other vein of the area for vascular outflow

5. The reconstructive team, given their precise concept of the characteristics and quality needed for a successful reconstruction, should ideally perform the vascular access dissection.

Second Flap

Once vascular access is obtained, attention should be turned to raising and transferring an appropriate flap. This is the time to accurately assess the defect created as well as the characteristics required from the flap to be used. On occasion only a combination of flaps can provide the optimal characteristics of structural rigidity and surface conformity. For example, a free fibula would provide the best structural characteristics but only mediocre surface coverage, whereas a radial forearm free flap would provide the best coverage with thin, pliable, well-vascularized skin but a bone that is only marginally adequate.²¹ This is the time to think of a combination of flaps. This becomes a daunting task, especially taking into account the difficulties mentioned regarding vascular access. Attaching both flaps to the same recipient vessels or piggybacking the second flap on the first is always an option to be considered, keeping in mind that one may end up overtaxing the vascular access vessels. In general, separate vascular access should be provided for each flap if at all possible.

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