Reconstructive Surgery



Fig. 2.1
Radiation effect. This adolescent patient underwent orbital extenteration for a rhabdomyosarcoma at the age of 4. She had free tissue transfer elsewhere followed by radiation. This case demonstrates the dramatic ill effects of radiation therapy on the growing maxillofacial skeleton. The mandible, maxilla, and orbit are substantially underdeveloped on the affected side



Once the reconstructive surgeon fully understands the anatomic requirements and other treatment modalities to be employed in management of the tumor , a series of reconstructive options should be generated. In some instances there may be one clear “first option”, in other instances there may be two or three equivocal options. Regardless, it is necessary to have at least one alternative procedure going into the operating room. This “lifeboat” may be deployed when intraoperative conditions change (e.g., unrecognized tumor progression, patient instability) or if the primary reconstruction modality is unsuccessful (e.g., partial or complete flap loss). When the reconstructive surgeon meets the patient and family, the rationale for the various the options should be fully discussed along with the advantages and disadvantages inherent to all reconstruction choices.

Equally important to interprovider consultation, preoperative planning must involve the parents and, when appropriate, the patient as well. The family will be overwhelmed by the diagnosis and there is often a sense of urgency to proceed as quickly as possible. The family may have been told that some form of “plastic surgery” or “reconstruction” will be required prior to the consultation with the reconstructive surgeon . A fine line must be walked between giving the family hope and inadvertently leading the family to have unrealistic expectations for the reconstruction. In addition to defining the defect and the reconstruction needs of the patient, the preferred treatment option(s) will be outlined. These may change based on anatomic considerations following physical examination or psychosocial considerations. For example, scarring from previous surgery may preclude specific donor sites for tissue or recipient vessels in case a microvascular procedure is required . Fortunately, unlike adult head and neck cancer patients , the effects of tobacco, diabetes, and other chronic comorbidities are rarely encountered. However, psychosocial considerations especially in adolescent patients, must be accounted for. It is important for the reconstructive surgeon to assess the family’s and patient’s understanding and tolerance for the reconstructive procedure being considered. In some cases, a simpler reconstruction with a less than ideal aesthetic outcome may be preferred if the surgical risks, recovery time, or postoperative restrictions are unacceptable to the patient or family.

All donor sites or potential donor sites for tissue, areas of scarring, and secondary deformities should be disclosed along with expectations for functional and aesthetic limitations at both the donor and recipient sites following surgery. Furthermore, depending on the age of the child, special attention should be given to the effects of growth on both of these locations. In many instances, additional procedures later in childhood will be required to address growth differences in the area of reconstruction. When this can be anticipated, the family should be made fully aware of a secondary procedure. In some instances, optimal reconstruction may require a series of staged procedures over time. Each patient and family should be viewed as unique with specific anatomic, psychological and social considerations. Care by the reconstructive team should be viewed as individualized, long-term, and may even exceed that of all other care team members.



Intraoperative Considerations



Timing and Sequence


A two-team approach is often helpful to minimize patient anesthesia and surgeon fatigue. In these situations, the free tissue flap is raised simultaneously with the extirpative operation . Clear communication between the oncologic and reconstructive teams is vital in these cases, especially when a skin flap is required. With poor communication between the teams, it is not uncommon to raise a flap that is too small for the defect. Certainly, the safest approach is to wait until the defect is complete. In our experience, however, most cases are amenable to a two-team approach.


Anesthesia


If combined with cancer ablative operations, head and neck reconstructive procedures are often lengthy. An experienced anesthesia team is crucial for optimizing care and minimizing complications.


Airway

In cases that involve the oropharynx, a nasal ray endotracheal tube is obligatory. The tube can be secured to the caudal septum with a heavy silk stitch. To avoid alar rim skin necrosis, the entire tubing apparatus should be brought inferiorly and secured to the patient’s foam-padded forehead with tape. A straight accordion tube extender is often useful to lengthen the circuit and avoid kinks. The tubing closer to the anesthesia machine can also be secured to the back of the headrest for additional security. Once this process is complete, the surgeon should check the integrity of this construct by turning the head in either direction.


Positioning

The positioning of the patient will depend to some extent on the reconstructive plan. In the case of pedicled flaps and most free tissue flaps, supine positioning is adequate. If a large defect is anticipated and a latissimus flap is considered for reconstruction, it may be prudent to harvest the muscle flap first in a lateral decubitus position, then partially close the donor site and turn the patient supine for the extirpative operation.


Tubes and Lines

Hemodynamic instability is rare during resection and reconstruction of most pediatric head and neck tumors . The main exception to this is in large vascular malformations, especially arteriovenous malformations. As such, invasive monitoring is typically limited to an arterial line and at least one and usually two peripheral intravenous lines. If postoperative chemotherapy or frequent blood sampling is anticipated postoperatively, a central venous catheter may be placed at the outset of the procedure. In patients coming to the operating room with a previously placed port-a-cath™ or long-term indwelling central venous catheter, special care must be taken to ensure appropriate handling and interrogation of these sites if they are to be used. The use of such devices should be cleared with the oncology team, parents, and the surgical team caring for the line. A nasogastric or orogastric tube is usually needed—initially for decompressing the stomach and potentially following surgery for nutrition.


Medication

A broad-spectrum antibiotic that covers oral/nasal flora is routine and should be continued in the perioperative period. Other medications to consider for postoperative comfort are antiemetics and pain medications. The surgeon should communicate early with the anesthesiologist about the use of vasopressors. Too often, a wide-open arterial anastomosis has been redone only to find that the agent responsible for the pale flap was the vasopressor. Fluid, colloid, or blood product administration should be the first line of treatment in these cases.


Technical Considerations


Several important technical considerations are related to the actual execution of the operation merit discussion. Careful attention to these issues separates the good outcomes from the potential disaster cases.


Oral Cavity Separation

One of the most difficult complications of oropharyngeal reconstruction is the dreaded fistula [312]. Fistulas may develop between the oropharynx and the nasal cavity or the skin. Typically, they occur at the flap and native mucosa juncture. To minimize the risk of fistulas, one should consider the causative factors: poor healing and inadequate seal. Poor healing may result from ischemia, infection, or a suboptimal environment (such as bathing in saliva or a radiated tissue bed). Ischemia can be controlled by bringing healthy, well-vascularized tissue to the defect and by resecting all poorly perfused tissues. Inadequate seal is almost always a result of poor surgical planning or execution. The most problematic areas for obtaining a tight seal are at the gingiva, the palate, and posterior mouth. Patients with intraoral tumor involvement, radiation, or poor oral hygiene may present with mucosa that is friable. The right approach is to remove all of the friable and suboptimal tissue from the area so that a tight seal can be created with the newly transferred flap and the surrounding tissues.


Brain–Mucosa Separation

When reconstructing defects that involve the cranial base, it is critical to obtain a good seal to separate the brain from the mucosa [13]. Tumor extirpation operations that involve the cranial base typically leave a large soft tissue defect. Obliteration of the resulting dead space is paramount to avoid cerebrospinal fluid leakage and infection. It is not uncommon to have to utilize a muscle flap in addition to a fasciocutaneous flap in these cases—the former for obliteration of the dead space and the latter for mucosal reconstruction.


Microsurgery

The importance of adequate vessels for microvascular anastomosis cannot be overstated—the larger the vessels, the higher the likelihood of success . Source vessels found in the neck have reliable anatomy and flow. These vessels may be too distant for more cephalic defects such as the scalp or orbit; in which case, the facial or superficial temporal vessels may be substituted [14]. In head and neck reconstruction , one rarely encounters difficulty in finding a suitable artery. However, finding an appropriate vein can sometimes be challenging. Good communication between the extirpative team and the reconstructive team from the outset of the procedure may allow for the identification and preservation of useful recipient vessels later in the procedure. In situations where the area is heavily scarred or has been previously radiated, one should consider (a) vein grafting to the opposite side or (b) use of the ipsilateral cephalic vein. It is rarely worth the risk to use less than optimal vessels in a zone compromised by scarring or radiation, to avoid the additional effort of vein grafting, using the contralateral side or the ipsilateral cephalic vein. We have found the cephalic vein quite useful in difficult outflow situations. A long segment can be harvested from the ipsilateral arm using multiple stab incisions. Minimal morbidity, anatomic consistency, and long length make this vein a perfect “bail out” strategy in difficult situations. There is ongoing debate in the literature about immediate versus delayed use of arteriovenous loops. The most recent literature suggests that staging of arteriovenous loops is not necessary [15].


Flaps


In this section, we will outline common flaps that are utilized for head and neck reconstruction. These flaps have consistent anatomy, low donor site morbidity, and long, reliable pedicles that allow a wide reach in the head and neck—they are the workhorse flaps of head and neck reconstruction [16].


Radial Forearm Flap [17, 18]

This flap provides thin, reliably perfused tissue based on a long pedicle for reconstruction of small to moderate sized defects. The anatomy is consistent, the flap is easy to harvest, and outcomes have been excellent [6, 7, 11, 12, 16, 1921]. It can be harvested as a fasciocutaneous flap or an adipofascial flap. Inclusion of the medial or lateral antebrachial cutaneous nerve creates a neurosensory flap that may be useful, to restore sensation to areas such as the palate. For small flaps, the donor site can be closed linearly. For larger flaps, a skin graft is required. The healing of this skin graft can be problematic if the paratenon over the flexor carpi radialis tendon is stripped [2124]. Prior to harvesting this flap, one must perform an Allen’s test to confirm integrity of the superficial palmar arch.


Anterolateral Thigh Flap

Based on the descending branch of the lateral femoral circumflex artery, this versatile flap provides a substantial surface area of skin for reconstruction of large defects in the head and neck [16, 2530]. The anatomy of the flap and pedicle are reliable and consistent. A large amount of skin and subcutaneous fat can be harvested with the flap and the donor site morbidity is minimal [31]. In some cases, the vascular pedicle courses along the fascial interface between the rectus femoris and the vastus lateralis muscles. However, in most cases, the vascular pedicle is intramuscular, thus making the dissection more tedious. In larger patients, its relatively remote location from the head and neck, as well as its anterior location makes it amenable to a two-team approach.


Rectus Abdominis (Myo or Myocutaneous)

This flap is used in a variety of anatomic locations and in head and neck reconstruction can provide cutaneous coverage or fill large cavities (Figs. 2.22.7) [6, 8, 13, 32]. The flap is harvested from the lower abdomen, preferably through a low transverse incision when only muscle is required or with an ellipse of skin and fat contiguous with the underlying muscle when coverage or lining is needed. The blood supply to the flap is via the inferior epigastric system. The pedicle is typically large, long, and easy to dissect. Depending on the amount of fascia taken with the muscle, the abdominal defect can be prepared directly or with a small mesh patch. Attention must be paid to proper closure as bulges or hernias may result. Abdominal wall function and trunk support is not impacted as long as the contralateral rectus muscle is functional. When placed low enough, the donor site scar is fairly inconspicuous.

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Dec 28, 2016 | Posted by in PEDIATRICS | Comments Off on Reconstructive Surgery
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