Chapter 2, Surgical Approaches to the Craniocervical Junction for the Resection of Chordomas (continued)
SURGICAL APPROACHESPrevious Page | Page 13 | Next Page
The surgical approaches can be divided into anterior, anterolateral, and posterolateral. All of these approaches can be useful either individually or in combination in the management of chordomas (2, 7, 10, 26). It is important to understand the areas of access provided by each approach and, more importantly, to understand the limitations and potential risks imposed (29).
The anterior approaches that are useful in accessing the anterior craniocervical junction can be broadly divided into transcranial (subfrontal transbasal) and transfacial. These are noted in Table 4.1.
TRANSMAXILLARY/LEFORT I, WITH MEDIAL MAXILLECTOMY
The transmaxillary approach is best suited for extradural lesions extending into the sphenoid and the upper and middle clivus with minimal lateral extension (7, 10, 18, 22, 32, 38, 40, 41). This approach provides the most direct access to the clival tumors in the ventral midline, such as chordomas and chondrosarcomas (11, 42). The transmaxillary approach further expands the conventional transnasal approach and is well suited for lesions that are too rostral on the clivus for a transoral approach (6, 8, 9, 43). In the transmaxillary approach, the lateral boundaries are defined by the medial pterygoid plates, the internal carotid arteries (ICAs) at the level of the foramen magnum, the cavernous sinus, the hypoglossal canals, and the jugular foramen. An extension of this approach can be performed via a midline sagittal split of the maxilla and the soft palate to provide a further caudal exposure to the craniovertebral junction.
Case Illustration of the Transmaxillectomy Approach
A 27-year-old, left-handed woman presented with headaches since 1995. The headaches were severe and progressive and were worse during her menstrual cycles. During the workup, she had an MRI scan performed, which revealed a tumor in her lower clivus (Fig. 2.1). A transnasal endoscopic biopsy was performed and revealed the tumor to be chordoma. Aggressive treatment was planned. Because of the tumorís midline location, with no lateral extension, a maxillectomy approach was undertaken (Fig. 2.2). She underwent a transfacial approach to the clivus, which consisted of a bilateral maxillotomy and a medial maxillectomy. In this approach, the prevertebral muscles were taken down and the opening in the sphenoid sinus was visualized. Using the navigation system, the rostral, caudal, and lateral limits of the tumor were defined. The clival bone was carefully drilled down. The retropharyngeal portion of the tumor was clearly visible after the longus colli muscles were removed. The tumor was visualized and removed in a piecemeal fashion. The tumor had eroded through and gone through the periosteal layer of the dura. The inner layer of the dura towards the brainstem was, however, intact. The retropharyngeal portion of the tumor was also removed in a progressive fashion. The remainder of the clivus-involved bone was drilled until no more abnormality was identified. Intraoperative image-guided navigation and endoscopic inspection was very helpful. It appeared that we were almost at the level of the hypoglossal canal, which was left intact and not interfered with. The pharyngeal flap was sutured with the Mitek anchor in place. A gross total removal of the tumor was achieved along with resection of the surrounding bone.