44 Transmaxillary Transpterygoid Approach The transmaxillary transpterygoid approach is a variant of the standard Le-Fort I transmaxillary approach, suitable for midline extradural tumors, extending from the sella turcica to the anterior rim of the foramen magnum and laterally to the internal carotid artery (ICA), invading the pterygopalatine fossa, the medial infratemporal fossa and the medial parapharyngeal space. • Clival chordomas and chondrosarcomas. • Other non-chordomatous lesions of the clivus. • Esthesioneuroblastoma. • Malignancy of the anterior skull base-sinonasal tumors. • Downward retraction of the maxilla can be improved by using tracheostomy or submental orotracheal intubation according to Hernandez-Altamir (see Chapter 43). • Subsequent enhanced exposure of the lower clivus is obtained. • Position: The patient is positioned supine with the head fixed to a horseshoe head holder. • Body: The body is placed in neutral position with the trunk elevated of 30° to increase venous backflow and the legs elevated at the level of the heart. • Head: The head is tilted back 20°and toward the left shoulder 25°. The surgeon is placed on the right side of the patient. • Anti-decubitus device: Rolls are placed under the knees. • The zygoma must be the highest point in the surgical field. A mucoperiosteal incision is performed between the first molars, 1 cm above the gingival reflection along the upper alveolar margin, leaving a cuff of mucosa on the gingival side. • Superficial temporal artery. • Facial nerve. • Mucosal level ◦ Gingival mucosa is detached till the maxillary-malar reflection on both sides and the floor of the nasal cavity are identified. • Bone exposure ◦ The bony exposure is continued to the level of the last molar. ◦ Subperiosteal dissection is carried out to expose the anterior maxilla and the piriform aperture, as far as the inferior rim of the infraorbital foramen is exposed. ◦ The infraorbital nerve is identified at the exit from its canal. The cartilaginous septum is detached from the nasal spine and vomer. • Infraorbital nerves. • A Le Fort I osteotomy is performed 8-10 mm above the roots of the teeth with an oscillating saw. • The nasal septum is then divided from the maxilla on the midline, and a curved chisel is used to divide the pterygoid-maxillary junctions. • The hard palate is down-fractured and mobilized into the oral cavity. • A self-retaining retractor is positioned between the maxilla and the hard palate. • Palatine nerves and arteries. • The sphenoid sinus is opened and the posterior sinus wall is drilled out, exposing the sellar floor, the carotid and optic prominences (Fig. 44.1). • A longitudinal incision is performed on the midline along the rhinopharynx mucosa and the parapharyngeal muscles, together with the mucosa, are dissected in a subperiosteal fashion from the underlying clival bony surface. • Clival resection is completed by drilling the middle and lower clival bone until the foramen magnum. • Internal carotid arteries (ICA): C3, C4 and C5 segments. • Optic nerves and chiasm. • Lateral exposure is completed by removing the inferior and middle turbinates and by resecting the posterior wall of the maxillary sinus. • Pterygopalatine fossa is opened, gaining access to the third segment of the maxillary artery, which is mobilized laterally by dividing the sphenopalatine artery. • The greater palatine artery is preserved. The vidian nerve is completely skeletonized to the lacerous segment of the internal carotid artery. • The pterygoid plates on both sides are removed, widening the paraclival dura exposure to the infratemporal segment of the mandibular branch of the trigeminal nerve (V3). • The Eustachian tube can be divided opening the surgical access to the parapharyngeal space. • ICAs: C2, C3 and C4 segments. • Maxillary arteries. • Greater palatine nerves and arteries. • Pterygopalatine ganglions. • Maxillary (V2), and mandibular branch (V3) of the trigeminal nerve. • Eustachian tubes. • Twelfth cranial nerves (hypoglossal nerve). • The dura is divided longitudinally on the midline. • Bleeding from the basilar plexus must be managed by compression and by using hemostatic agents.
44.1 Introduction
44.2 Indications
44.3 Anesthesia And Patient Intubation
44.4 Patient Positioning
44.5 Mucosal Incision (See Chapter 43)
44.5.1 Critical Structures
44.6 Soft Tissues Dissection (See Chapter 43)
44.6.1 Critical Structures
44.7 Maxillar Osteotomy (See Chapter 43)
44.7.1 Critical Structures
44.8 Clival Exposure
44.8.1 Critical Structures
44.9 Paraclival Exposure (Figs. 44.2–44.5)
44.9.1 Critical Structures
44.10 Dural Opening (Fig. 44.6)
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