**8. Postoperative evaluation**

The postoperative care and management of complications require an understanding of osseous wound healing and the potential causes of failure. Loss of skeletal stability as a result of loss of fixation allows for motion at the wound interface, with secondary impairment of vascula‐ rization. Early recognition of flap compromise is associated with improved chances of flap salvage. The ideal flap monitoring technique should be reliable, reproducible, easily inter‐ pretable, inexpensive, noninvasive, rapidly responsive to changes in microcirculation, and able to provide continuous monitoring in the immediate postreconstructive period. The clinical examination should focus on capillary refill time (>3 seconds is the cutoff), which provides information on the adequacy of the arterial supply. Early venous outflow obstruction results in capillary refill that is too brisk. The color of a flap can also provide information about arterial insufficiency. A pale flap signifies poor flap perfusion, whereas one with outflow obstruction is congested and hyperemic. Skin temperature can assess the adequacy of circu‐ lation in digits but is of little use when applied to flaps for reconstruction, as changes in ambient temperature affect the measured surface temperature readings. The most invasive monitoring method is blood flow from the flap. Flow of oxygenated blood, from a needle puncture, indicates good perfusion, whereas dark red blood or sluggish flow is a prognostic indicator.

For example, implants placed in the mastoid bone or the temporal bones allow an auricular implant to be fixated via bar splinting. A nasal prosthesis can use a similar retention technique and have its fixtures placed in the floor of the nose. And in situations in which tumor ablation included the orbit, implants can be placed in the supraorbital rim region [173]. As with intraoral Buried flaps, or flaps used for pharyngoesophageal reconstruction, require some other form of monitoring technique, because direct visualization is not possible. Flexible fiberoptic telescopes have been used, but this method cannot be performed on a continual basis. To visualize a segment of jejunum used for pharyngeal reconstruction, a sheet of silicone rubber (Silastic) is placed over the segment of jejunum and the skin is left open to provide a "window" to allow a direct view of the jejunum. A flap can be designed with a segment externalized so that the surgeon can readily visualize it. The cutaneous part can often be partially externalized and incorporated in the wound closure to serve as an indicator of graft survival; this also decreases wound tension. Tissue that is unnecessary for reconstruction and is supplied by the vascular pedicle can be externalized and observed for impairment of blood supply.

There are a number of adjunctive monitoring devices that can be used to assess the adequacy of tissue perfusion. An electromagnetic flowmeter determines the absolute blood flow in a vessel by electromagnetic induction and allows immediate and continuous readings to see slow or rapid changes. The ultrasonic Doppler flowmeter has been in clinical use for more than 30 years and is useful if one is certain that the flow signal heard is from the vascular pedicle. Arterial thermometry is a system that measures temperature difference across a vascular anastomosis with implanted thermocouple probes. Fluorescein has been used to identify flaps with inadequate perfusion; when injected intravenously, it diffuses out to the capillaries into the interstitial fluid. The staining can then be visualized under ultraviolet illumination. The more intense the staining, the better the perfusion, and vice versa. The dermofluorometer enables the clinician to quantify minute degrees of fluorescence and uses smaller doses of the drug to prevent allergic reactions. Radioisotope washout of xenon 133, sodium pertechnetate Tc99m, iodine 131, and sodium 24 has been used to indicate the adequacy of perfusion; after administration of an isotope, clearance from the flap is monitored and correlated with flap perfusion (i.e., greater clearance equals greater flap perfusion). Pulse oximetery can detect pulsatile blood flow until the artery is 95% occluded. Laser-Doppler velocimetry is currently the best tool for objective monitoring of flaps. It must be in place when the flap is known to have good perfusion, because changes in this initial value are the important parameter. The laser-Doppler velocimeter can provide an accurate, easily interpretable readout of tissue perfusion that is rapidly responsive to changes in perfusion. Duplex Doppler ultrasonography is capable of identifying and characterizing blood flow from small, superficially located vessels, similar to those involved with microvascular surgery. Different shades of gray are assigned to stationary areas, whereas color is assigned to areas of motion such as blood flowing within a vessel. Vessels as small as 1 mm in diameter can be identified. Transcutaneous oxygen monitoring is also an option, where Po2 is measured directly to assess the state of microcir‐ culation. Finally, changes in interstitial fluid hydrostatic pressures can reflect changes in blood flow [175]. Radiologic literature on bone graft evaluation is sparse. Follow-up assessment of skeletal reconstruction with plain radiographs and cephalometric studies in the immediate postoperative period is needed to document the position of bone segments and the location of hardware. However, data on the evaluation of primary bone tumors and bone allografts stress the role of plain film radiography. In 1992, Soderholm and colleague [176] studied the effectiveness of using plain film radiography in the follow-up and prognosis of non-vascular bone grafting used in mandibular reconstruction. They concluded that narrow-beam radiog‐ raphy and spiral tomography are excellent tools for the evaluation of bone resorption and bony healing of mandibular grafts. Panoramic radiographs are able to visualize the whole mandib‐ ular bone and are used for a general assessment; tomography is used for specified, selected diagnostic tasks, such as to visualize bone resorption within the graft and under the plate. After reconstruction of large defects in the oral cavity or the oropharynx with myocutaneous or free microvascular flaps, physical rehabilitation by a therapist trained in speech and swallowing is of paramount importance, as these reconstructive procedures cannot fully restore the patient's ability to masticate, swallow, or speak. The major aims of physical therapy are to decrease the amount of facial deformity and to limit the loss of oral opening. Oral opening exercises are initiated as soon as the patient can tolerate them. Stretching exercises three to four times a day are adequate home regimens. A specialized therapist may use the Therabite mouth opener (Therabite Co., Bryn Mawr, PA) to improve maximal opening. Also, those patients who have had neck dissections require physical therapy for shoulder pain and trapezius weakness. Range-of-motion exercises are necessary to prevent frozen shoulder and worsening pain.
