Management of Unfavorable Outcomes in Head and Neck Free Flap Reconstruction

Complex head and neck reconstruction often mandates free tissue transfer to achieve the most optimal outcomes. Unfortunately, such challenging cases are not without risks of complications, the most dreaded of which is loss of the free flap. Aside from loss of the free flap, there are several other potential complications that can result following head and neck reconstruction. Certain complications are avoided with careful planning, others require significant revisions and in certain cases another free flap. This article presents the experience managing a series of unique complications following free flap head and neck reconstruction.

Key points

  • Microvascular head and neck reconstruction aims to restore form and function and poses unique challenges for the reconstructive surgeon, and complications can be devastating.

  • Maximizing success in free flap head and neck reconstruction requires diligent preoperative planning, appropriate flap selection, and precise surgical technique and postoperative monitoring and management.

  • Compromised flap perfusion mandates early detection and definitive exploration and intervention to maximize flap salvage rates.

  • Complications unrelated to the microvascular anastomosis and perfusion of the flap unfortunately are inevitable; however, appropriate management requires prompt recognition and often aggressive intervention.

Introduction

Success rates in microvascular head and neck reconstruction are greater than 95% in most high-volume institutions. However, despite these high success rates, there remains a percentage of patients who suffer the catastrophic consequence of losing a free flap or other complications even with a successful free flap, which for head and neck defects can be incompatible with life. Patients undergoing reconstruction following tumor extirpation present unique challenges to the reconstructive microsurgeon given the high prevalence of tobacco use, malnutrition, prior or postoperative radiation damage, and history of prior surgeries. However, successful reconstruction is not simply achieving high flap survival rates, but is also aimed at optimizing form and function and minimizing nonmicrosurgical complications. These objectives require appropriate flap selection and design, careful preoperative planning and meticulous technique, and diligent postoperative monitoring with a low threshold for definitive operative exploration for any suspicion of compromised flap perfusion. Despite a successful flap and recovery, patients do still suffer from complications. This article provides a synopsis of our approach to maximizing flap success and managing unfavorable outcomes. Many other centers have otolaryngologists performing some or all of the head and neck reconstructions. The head and neck reconstruction experience at The University of Texas MD Anderson Cancer Center is unique in that the plastic surgery department is responsible for all of the high-volume (300–400 free flaps per year) reconstructions, which we hope helps reconstructive microsurgeons worldwide.

Introduction

Success rates in microvascular head and neck reconstruction are greater than 95% in most high-volume institutions. However, despite these high success rates, there remains a percentage of patients who suffer the catastrophic consequence of losing a free flap or other complications even with a successful free flap, which for head and neck defects can be incompatible with life. Patients undergoing reconstruction following tumor extirpation present unique challenges to the reconstructive microsurgeon given the high prevalence of tobacco use, malnutrition, prior or postoperative radiation damage, and history of prior surgeries. However, successful reconstruction is not simply achieving high flap survival rates, but is also aimed at optimizing form and function and minimizing nonmicrosurgical complications. These objectives require appropriate flap selection and design, careful preoperative planning and meticulous technique, and diligent postoperative monitoring with a low threshold for definitive operative exploration for any suspicion of compromised flap perfusion. Despite a successful flap and recovery, patients do still suffer from complications. This article provides a synopsis of our approach to maximizing flap success and managing unfavorable outcomes. Many other centers have otolaryngologists performing some or all of the head and neck reconstructions. The head and neck reconstruction experience at The University of Texas MD Anderson Cancer Center is unique in that the plastic surgery department is responsible for all of the high-volume (300–400 free flaps per year) reconstructions, which we hope helps reconstructive microsurgeons worldwide.

Defect-specific reconstruction

Head and neck reconstruction aims to restore form and function and particularly for extensive defects, free tissue transfer represents the best option for achieving the most optimal outcomes. The selection for donor sites largely depends on the extent and type of defect and patient body habitus and available donor sites taking into consideration surgeon comfort and experience. Over the years, we have developed our algorithmic approach to reconstruction of head and neck defects to minimize complications and optimize outcomes, which corresponds with algorithms from other high-volume institutions.

At our institution, we favor osteocutaneous free flaps for composite defects of the maxilla or mandible; however, in certain circumstances, soft tissue flaps are used. For example, mandibular defects, with the condyle sacrificed and the defect not extending anterior to the parasymphysis, soft tissue flaps often provide adequate postoperative function. This approach applies to reconstruction following oncologic resection and for cases of osteoradionecrosis (ORN). Similarly for defects involving the maxilla, a soft tissue flap may be sufficient if the alveolar bone defect does not extend beyond the canine tooth; however, for more extensive defects a bony reconstruction is indicated.

For mucosal defects of the floor of mouth or inner cheek, we prefer a thin pliable flap, which in our patient population is a forearm-based flap, but occasionally an anterolateral thigh (ALT) flap can be used in thinner patients. A similar algorithm is used for reconstruction of glossectomy defects where a thinner more pliable flap, such as a forearm or thin perforator ALT, is used for partial or hemiglossectomy defects, whereas a bulkier flap, such as a combined ALT/vastus lateralis flap or a rectus abdominis myocutaneous (RAM) flap, may be necessary for a subtotal or total glossectomy defect. Reconstruction of extensive defects, such as those involving the tongue and the mandible, may often require the use of two free flaps to restore and optimize form and function, which can be performed safely with excellent success rates and outcomes ( Fig. 1 ). Similarly, for through-and-through defects, two free flaps are often necessary for reconstruction of the intraoral defect and provide coverage for the external skin.

Fig. 1
( A ) Extensive defect resulting in through-and-through composite mandibulectomy defect requiring bony reconstruction of the mandible and soft tissue coverage. ( B ) Free fibula osteocutaneous flap for reconstruction of mandible defect. ( C ) Free ALT flap for resurfacing of external skin.

Reconstruction of pharyngoesophageal defects results in fewer complications and superior function if a portion of the pharyngeal or esophageal wall is preserved. The ALT flap represents our flap of choice for near-total and circumferential defects especially in the setting of prior radiation and surgery where a neck resurfacing may be necessary. In such circumstances, an ALT with two independent skin islands is used to reconstruct the pharyngoesophageal defect and provide coverage of the neck ( Fig. 2 ). We reserve jejunal free flaps as a second-line option for cervical esophageal defects and the supercharged jejununal conduit for total esophagectomy defects when the option of a gastric pull-up is not possible. In addition to avoiding a laparotomy, our experience is that a fasciocutaneous flap provides superior speech rehabilitation compared with intestinal flaps with comparable swallowing function. In our series of 349 cases, circumferential defects not surprisingly are associated with increased complications including fistula and strictures, and therefore preservation of any viable mucosa is critical for maximizing outcomes and providing patients with a successful reconstruction. Although rare, tracheal defects can also be successfully reconstructed using free tissue transfer, and even when coupled to esophageal disease, such extensive defects can still be salvaged with the use of fasciocutaneous free flaps and supercharged jejunal flaps.

Fig. 2
( A ) Partial pharyngectomy defect following salvage for recurrent laryngeal cancer after prior radiation. ( B ) Double skin paddle ALT for reconstruction of pharyngeal defect and ( C ) external skin resurfacing.

Finally, scalp reconstruction is determined based on the size of the defect. Local scalp flaps and rotation flaps are generally used for small defects. Successful reconstruction of larger defects is achieved with either free muscle or fasciocutaneous flaps with equivalent outcomes. For larger defects, the latissimus dorsi muscle with a skin graft is the flap of choice. When defects also require a cranioplasty for reconstruction of the calvaria, customized implants or titanium mesh have proven to be effective with low long-term complication rates.

Management of microvascular complications

Postoperative management is critical to maximizing success rates in microvascular surgery. Any concern for a microvascular complication mandates immediate evaluation by a microsurgeon with a low threshold for operative exploration. Prophylactic anticoagulants, such as heparin or enoxaparin, dextran, or aspirin, have not demonstrated improved outcomes and are not routinely at our institution. The most important factors in maximizing flap success rates are careful planning, precise technical execution, and attention to detail anticipating potential complications. Performing an additional venous anastomosis has not been shown to decrease complication rates or improve flap salvage and, therefore, is not recommended because a second venous outflow has been shown to decrease volumetric flow through both anastomoses. Signs of flap compromise, such as increased swelling and bruising, change in color, and loss of the Doppler signal should prompt an immediate return to the operating room if the patient is medically stable ( Fig. 3 ). Early intervention remains the single most significant predictor of flap salvage. A negative exploration is far preferable to a lost free flap. A proposed algorithm for addressing flap compromise is summarized in Fig. 4 .

Fig. 3
( A ) Total glossectomy defect for recurrent squamous cell carcinoma of the tongue after prior radiation therapy reconstructed with a free ALT flap ( B ). ( C ) Patient developed venous congestion of the flap on postoperative Day 1 requiring emergent exploration. ( D ) Postoperative photograph after successful flap salvage.

Fig. 4
MD Anderson Cancer Center plastic surgery algorithm for management of compromised free tissue transfer.

Case reports of unfavorable outcomes

Case 1

The patient underwent a free radial forearm flap following a maxillectomy and then developed significant hollowing of the malar prominence following radiation therapy. The patient was disturbed with the cosmetic result and received two rounds of autologous fat grafting to restore the volume deficit. Although the patient achieved a reasonably aesthetic outcome, two additional operations were needed to achieve the desired result ( Fig. 5 ). Given the anticipated effects of radiation, a larger flap should have been used for the initial reconstruction. A larger flap, such as an ALT or perhaps a lateral arm flap, would have provided more bulk that may have appeared excessive initially but would have settled to the appropriate size following radiation. However, alternatively, if a larger flap were performed, there is a potential risk that the patient may need to undergo a debulking procedure if the flap is too large. Patients should be counseled regarding the need for potential revisions and autologous fat grafting or liposuction may be necessary to augment or reduce a flap to achieve the most aesthetic outcome.

Fig. 5
( A ) Preoperative photograph of patient before undergoing a suprastructure maxillectomy for squamous cell carcinoma ( B ) that was reconstructed with a free radial forearm flap. ( C ) Postoperative photograph after completing radiation therapy; the patient lost a noticeable amount of volume with hollowing of his malar region. ( D ) Postoperative photograph after two rounds of autologous fat grafting with improvement in the fullness of his cheek.

Case 2

Following an extensive scalp and calvaria resection for squamous cell carcinoma, the patient had a free latissimus dorsi muscle flap for coverage with a skin graft. Unfortunately, the patient lost the distal-most aspect of the muscle requiring debridement and a second free flap to cover the exposed titanium mesh cranioplasty ( Fig. 6 ). The distal portion of the latissimus dorsi muscle may not be as well perfused on the main thoracodorsal vascular pedicle and can be injured during the elevation because traction on the muscle can compromise the perfusion to the distal flap. For large defects, careful elevation of the latissimus is critical to maximize the viability of the entire flap and if the defect is too large, potentially two free flaps may be necessary. In this particular instance, likely a combination of traction on a large flap and the patient’s resuming smoking led to necrosis of the distal portion. Therefore, postoperative management and careful technique and tissue handling are equally important in avoiding unfavorable outcomes.

Fig. 6
( A ) Extensive squamous cell carcinoma of the vertex of the scalp resulting in a large composite defect of the scalp soft tissue and calvaria that was reconstructed with titanium mesh ( B ) and a free latissimus dorsi muscle flap ( C ). ( D ) Postoperative photograph demonstrates loss of the distal aspect of the flap with initial loss of the skin graft and subsequently full-thickness necrosis ( E ). ( F ) Patient then underwent a second free vastus lateralis muscle flap with skin graft to cover the area of exposed titanium mesh following debridement of the necrotic latissimus flap.

Case 3

The patient underwent a prior gingival resection and was found to have positive margins that ultimately required a segmental mandibulectomy that was reconstructed with a free fibula osteocutaneous free flap. The titanium plate was contoured by the dental team and used for a single segment fibula osteocutaneous flap. Postoperatively, the patient reported malocclusion with an anterior open crossbite ( Fig. 7 ). The goal of mandibular reconstruction is to restore the patient’s ability to eat normally and restoring class I occlusion is critical. With the increasing use of computer-assisted design and modeling, precise cutting guides are manufactured to guide the osteotomies and are coupled to titanium plates that are milled to coincide precisely with defect. Unfortunately, this technology can be prohibitively expensive. Whenever performing a fibula osteocutanous free flap for mandibular reconstruction, it is critical to contour the titanium plate yourself and to maintain the patient in class I occlusion during the fixation. Before leaving the operating room, it is important to make certain that the condyles are not dislocated from the glenoid fossa and the patient is in proper occlusion. If there is dislocation or malocclusion, it is best to correct immediately because correction of malocclusion secondarily is exceedingly challenging.

Nov 21, 2017 | Posted by in Dental Materials | Comments Off on Management of Unfavorable Outcomes in Head and Neck Free Flap Reconstruction
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