Combined approach for extensive maxillectomy: technique development and cadaveric dissection.

The procedure is started by performing a total ethmoidectomy (or inferior/subtotal ethmoidectomy) and a wide maxillary antrostomy with standard sinus or powered instrumentation. This is followed by the resection of the entire medial wall of the maxillary sinus (including the inferior turbinate) and the inferior aspect of the middle turbinate. Subsequently, an incision is performed at the level of the ipsilateral gingivobuccal sulcus. The incision is made from the contralateral central incisor to the ipsilateral third molar. Blunt subperiosteal dissection of the soft tissues is performed with a freer dissector along the anterior wall of the maxillary sinus, until locating the infraorbital nerve (ION) superiorly and the zigomaticomaxillary fissure laterally Fig. 1 A. Vertically oriented osteotomies along the intermaxillary (IMF) fissure or segment, zigomatomaxillary fissure (ZMF), ascending process of the maxilla (APM), and transversally along the superior or inferior margin of the infraorbital neurovascular bundle are performed with powered instrumentation, in order to detach the anterior aspect of the maxilla Figs. 1 B-D, 2. An incision is made sagitally along the mucosa of the hard palate, which is raised and reflected with a soft tissue elevator. A nasal floor / palate osteotomy is performed with a powered saw, from posterior to anterior. It is preferred to make this osteotomy as close as possible to the medial maxillary wall to preserve more palatal bone to facilitate reconstruction, if oncologically possible. The sphenopalatine artery (SPA) and foramen (Fig. 3 A) are identified at the level of the ethmoidal crest. The SPA is clipped and cauterized and the foramen is opened with a small Kerrison roungeour (KR) forcep (Fig. 3 B). This instrument is also used to remove the adjacent posterior wall of the maxillary sinus in a lateral fashion (Fig 4 A). Having this done, the ITF and the PPF are exposed. The IMA is identified and clipped (Fig. 4 B). A KR or and angled drill can be used to continue the posterior osteotomy as laterally and anteriorly as possible, connecting it to the osteotomy previously performed along the ZMF (Fig. 5 and 6). Depending on individual’s anatomy, it may be difficult to extend the posterior osteotomy laterally and anteriorly, however, angled drills and endoscopes (45-70 degree) can be used endonasally, or a drill can be used to connect them by using the gingivobuccal approach (Fig. 7). Another option is to gain working space by drilling additional bone from the posteromedial aspect of the ipsilateral ascending process of the maxilla. Lastly, the nasal floor / hard palate osteotomy and the posterior osteotomy are connected with an angled drill, with or without transecting the pterygopalatine canal or pterygoid plates. Alternatively, the attachment of the maxilla to the pterygoid plates can be thinned out with a drill, and the maxilla can be dow-fractured in a controlled fashion. Once all the ostetomies are connected and the IMA is ligated, the remaining soft tissues (eg. soft palate) are divided sharply or using electrocautery. The floor of the orbit, ION, lamina papyracea, and superior aspect of ascending process of the maxilla are preserved in a subtotal maxillectomy. However, these structures can be removed (for a total maxillectomy) using the same instrumentation.