Oral Tongue and Floor Mouth
In this crucial chapter, a detailed introduction discusses the complex anatomy of the tongue and the most important functional correlates, along with a practical approach to clinical assessment of primary tongue lesions.
The importance of accurate imaging is stressed as a means for determining the true extent of resection necessary in a given case.
In order to best preserve as much lingual function as possible, the design of resection is extremely important and must be decided in advance following detailed examination and imaging.
Accordingly, three essential types of defects are described:
Type I, in which it is possible to achieve primary closure or avoid bringing in distant tissue for reconstruction.
Most of these excisions can be planned as a laterally based wedge in the vertical plane, and primary closure of most of these defects results in a normal looking tongue with excellent function.
For long, “linear” lesions along the lateral border, the wedge can be planned in a horizontal plane, resulting in a long scar along the lateral border.
For lesions that involve significant amounts of neighboring floor mouth, some form of tissue has to be brought in to avoid tethering of the tongue. The type and volume of tissue needed depends upon the plane and extent of the defect, and alternatives are shown, ranging from a small neighboring FAMM (facial artery myo-mucosal) flap to a split skin graft to microvascular flaps.
Type II, is essentially the “Hemiglossectomy” type defect with variations in location and extent. All these defects need reconstruction to avoid major affectation of function, mostly by fascio-cutaneous flaps. In all cases, it is optimal to restore tip function, which is crucial for articulation and for moving around the food bolus during mastication. It is also important to avoid tethering of the reconstructed tongue and providing substance posteriorly to enable the initiation of the pharyngeal phase of deglutition. If the substance loss is modest, a FRAFF reconstruction is generally preferred. With larger substance losses, the ALT flap or the Lateral arm flap are frequently preferred.
Type III defects are variations of the “Total Glossectomy” defect in which variable portions of the floor muscles / larynx / pharynx are involved. All these defects need reconstruction by high volume flaps. The ALT flap is the clear workhorse for these defects, although in some cases, the L. Dorsi free flap or the Rectus Abdominis free flaps may be employed. In all cases, adequate precautions against aspiration (Hyoid suspension, cricopharyngeal myotomy) are necessary for swallowing rehabilitation.
Patients who need massive resections such as total glosso-laryngectomy routinely need adequate reconstruction, most often with high volume fasciocutaneous free flaps such as the ALT.
Illustrative cases are demonstrated for all types of defects.