Tips and Techniques for the Combined Approach for Caudal Maxillectomy-inferior Orbitectomy

Caudal maxillectomy via an a combined intraoral and dorsolateral approach was first described by Lascelles et al (2003) and is an excellent approach for tumors of the mid-to-caudal maxilla which either arise or extend dorsolaterally and/or caudally to the alveolar margin. The combined approach provides better exposure, and thus improved ability to achieve hemostasis and completely excise the tumor, compared to the intraoral approach for more extensive caudal maxillary tumors. A CT scan is recommended for tumors of the caudal maxilla and orbit to determine the extent of the tumor, resectability, and to plan the surgical approach. In some cases, particularly those with more extensive involvement of the orbit, enucleation may be required to improve exposure and likelihood of achieving complete excision of the tumor.

Dogs are positioned in lateral recumbency with the mouth held open using a gag. The pharynx should be packed with gauze sponges to minimize the risk of aspirating blood and lavage fluid. The dorsolateral skin incision is created first with an incision lateral to midline of the dorsal aspect of the nasal cavity and extending caudally and ventrally to the eye along the zygomatic bone. This incision is continued through the subcutaneous tissue, between the paired levator nasolabialis muscles, and down to bone. Caudally, the ventral aspect of the globe is separated from the dorsal zygoma with a combination of sharp and blunt dissection leaving the conjunctival sac intact, while the masseter muscle is elevated from the ventral aspect of the zygomatic arch using a combination of sharp and blunt dissection. The most common complication of the combined approach for caudal maxillectomy is blood loss from the maxillary artery. The maxillary artery should be ligated early in the procedure, if possible, to prevent this complication. The maxillary and palatine arteries are exposed deep within the orbit by carefully retracting the globe dorsally and ligated with either suture material or metallic clips. Exposure may be limited and can be improved by resecting the zygomatic arch rostral to the orbital ligament, however this is often difficult and ligation of the maxillary artery is frequently completed at the end of the procedure when the bone segment is freed.  [...]