Novel Skin Reconstruction Techniques of the Maxillofacial Area

Introduction
Reconstruction of the maxillofacial area, and especially of the most rostral part, around the nasal planum, is challenging. Complete and wide excision of neoplasms is the primary goal of oncologic surgery, however cosmetically pleasing results are usually required to satisfy the owner of the animal with cancer. The modified nasal rotation flap has recently been described for reconstruction of a nasal planum defect as a result of chronic granulomatous inflammation, but the technique can be used to close defects of the dorsocranial nasal bridge after tumour resection as well. In addition, nasal planum reconstruction after excision of the central nasal planum and upper lip for squamous cell carcinoma will be discussed in this lecture, as well as the use of an intra-orally raised angularis oris based axial pattern flap for closure of a large hard palate defect.

Modified nasal rotation flap
A crescentic nasojugal flap, a local subdermal flap, has been described for reconstruction of the nasal tip in humans after removal of local carcinomas. This flap has been modified for use in dogs and cats, so that it can be used to close wounds of different sizes and shapes in the rostrodorsal region of the nose. The following four criteria must be taken into consideration before the outlines of the flap are drawn: the type of skull (brachycephalic, mesocephalic or dolichocephalic), the amount of (excess) skin covering the upper lip, the location of the defect and the dimensions of the defect. The procedure results in a good cosmetic appearance of the wound without excess tension in the donor and the recipient sites and prevents exposure of the upper canine teeth. For raising a unilateral flap, a line is drawn starting at the rostral part of the defect, along the border of the tip of the nose and continuing laterally in an arch shape to meet the alar groove. To avoid dog-ears on closure, and to minimize scar formation, a triangle is formed around the distal part of the crescent-shaped line that is going to be excised. The flap area is then automatically outlined by the caudal part of the triangle and the medial part of the defect. To avoid a second dog-ear on closure, two converging lines are drawn on the contralateral side of the nose, with the broadest part meeting the caudolateral part of the defect. The skin is incised along the predrawn lines and the two triangular-shaped skin areas are excised. The flap area is undermined to facilitate advancement to the tip of the nose. One stay suture (using 2-0 absorbable monofilament suture material) only is used to maneuver the flap. The flap is transposed into the defect and the subcutaneous tissue of the flap is attached to the adjacent subcutaneous tissue in an interrupted or continuous suture pattern using 3-0 absorbable multifilament suture material. The skin is then routinely closed. Bilateral use of this modified nasal rotation flap allows for closure of larger defects of the skin of the rostral nose in dogs and cats without creating the asymmetry that usually results from advancing a large amount of local tissue in this area. There are two variations of the bilateral flap technique: 1) Performing the technique bilaterally exactly as described for the unilateral technique allows for closure of relatively long, but not very wide, defects where both flaps meet in the midline. 2) For closing defects that are relatively short but wide, the flaps can be advanced and undermined further so that they cross the midline. One side can be used to close the more rostral part of the defect, while the second part is used to close the caudal part.  [...]