The transmaxilloethmoidal approach affords the surgeon a view of the sellar and parasellar regions. The approach can be used for clival chordomas, chondrosarcomas, or pituitary tumors with a large cavernous sinus or clival extension, for encephaloceles, and for medial orbital pathology.
Key Steps
Position: Supine
Step 1. Incise the paranasal skin incision (Fig. 2.1)
Step 2. Expose the maxilla and identify the infraorbital nerve (Fig. 2.2)
Fig. 2.1 (Step 1) Incise the paranasal skin.A skin incision is made lateral to the nasal border.Fig. 2.2 (Step 2) Expose the maxilla and identify the infraorbital nerve.The infraorbital surface of the maxillary bone is exposed. The infraorbital nerve is a landmark for the lateral limit of dissection. (ION, infraorbital nerve; LS, lacrimal sac; Mx, maxilla)Fig. 2.3 (Step 3) Identify the lacrimal sac.After exposing the infraorbital nerve, the lacrimal sac in the me-dial orbital wall should be identified. The lacrimal duct extends from the medial palpebral commissure to the lacrimal sac. (ION, infraorbital nerve; LS, lacrimal sac; Mx, maxilla; NMS, nasomaxillary suture)Fig. 2.4 Cut the nasolacrimal duct.The nasolacrimal duct is cut so that the lacrimal sac can be separated from the periorbita. (ION, infraorbital nerve; LF, lacrimal fossa; Mx, maxilla; NMS, nasomaxillary suture)Fig. 2.5 Expose the lacrimal fossa.The fossa for the lacrimal sac is found anterior to the posterior lacrimal crest. The lacrimal fossa overlies the anterior lacrimal bone and posterior frontal process of the maxillary bone. (LF, lacrimal fossa; Mx, maxilla)Fig. 2.6 (Step 4) Identify the anterior ethmoidal artery and nerve.Peeling off the periorbita from the medial orbital wall exposes the anterior ethmoidal artery, which passes through the anterior ethmoidal foramen in the suture between the ethmoid and frontal bones. (AEA&N, anterior ethmoidal artery and nerve; LF, lacrimal fossa)Fig. 2.7 (Step 5) Perform a maxillostomy and ethmoidectomy.Bone is removed from the anterior wall of the maxillary sinus to preserve the mucosa of that sinus. (ION, infraorbital nerve; MxS, maxillary sinus; NLD, nasolacrimal duct)Fig. 2.8 Maxillostomy and ethmoidotomy exposing the medial maxillary and anterior ethmoid sinuses.The maxillary and anterior ethmoid sinuses are exposed. The extent of the bone removed defines the limits of the surgical exposure. (Et, ethmoid sinus; ION, infraorbital nerve; MxS, maxillary sinus; NLD, nasolacrimal duct)Fig. 2.9 (Step 6) Remove the lateral wall of the nasal cavity.The wall between the maxillary sinus and the nasal cavity is opened. The middle and superior nasal conchae are parts of the ethmoid bone. The inferior concha is a separate bone that lies adjacent to the maxillary sinus. (EB, ethmoid bulla; ION, infraorbital nerve; IT, inferior turbinate; MT, middle turbinate; MxS, maxillary sinus; NLD, nasolacrimal duct)Fig. 2.10 Completion of the ethmoidectomy.An ethmoidectomy with removal of the middle turbinate is performed. (Et, ethmoid sinus; ION, infraorbital nerve; IT, inferior turbinate; MT, middle turbinate; MxS, maxillary sinus; NLD, nasolacrimal duct)Fig. 2.11 Exposure of the choana after removal of the nasal turbinates.The removal of the nasal turbinates exposes the nasal septum and choana. The choanae are the posterior openings of the nasal cavity. This opening is outlined by the medial pterygoid plate, the sphenoid bone, the vomer, and the palatine bones. (Ch, choana; NPx, nasopharynx; NS, nasal septum)Fig. 2.12 Identification of the orifice of the eustachian tube.The eustachian tube enters the pharynx behind the inferior turbinate. The orifice of the eustachian tube is seen in the lateral wall of the nasopharynx. The posterior wall is marked by a ridge produced by the posterior edge of the eustachian tube pushing out the mucosa and the torus. (Ch, choana; ET, eustachian tube; NPx, nasopharynx)Fig. 2.13 Relationship between the ethmoid sinus, the choana, and the nasal septum.Removal of the maxillary sinus, the nasal turbinates, and the ethmoid sinus opens a broad surgical corridor. The origin of the superior turbinate emanates from the roof of the ethmoid sinus. (Ch, choana; ET, eustachian tube; NS, nasal septum)Fig. 2.14 Identification of the natural ostium of the sphenoid sinus.Removal of the superior turbinate reveals the ostium of the sphenoid sinus. The ostium of the sphenoid sinus lies above the middle turbinate and behind the posterior edge of the superior turbinate. (Et, ethmoid sinus; OSS, ostium of the sphenoid sinus; NS, nasal septum)Fig. 2.15 (Step 7) Perform a sphenoidostomy.Opening the sphenoid sinus exposes the anterior wall of the sella turcica. (NS, nasal septum; SF, sella floor; SS, sphenoid sinus)Fig. 2.16 Overview at this stage.The sella turcica and the prominence over the right carotid artery are well seen. (CP3, carotid prominence formed by the C3 portion of the internal carotid artery; NS, nasal septum; SF, sella floor; SS, sphenoid sinus)Fig. 2.17 Identification of the C5 carotid prominence.The carotid prominence covering the C5 portion of the internal carotid artery that lies on the lateral wall of the sphenoid sinus is observed above the choana. (Ch, choana; CP5, carotid prominence formed by the C5 portion of the internal carotid artery; NS, nasal septum; SF, sella floor; SS, sphenoid sinus)Fig. 2.18 (Step 8) Expose the pituitary gland and bilateral cavernous wall.Removal of the anterior wall of the sella turcica reveals the dura covering the pituitary gland. The pituitary gland is seen from the paramedial oblique view. (CL, clivus; PG, pituitary gland; NS, nasal septum)Fig. 2.19 Exposure of the medial cavernous wall on the left side.The bulging of the C5 portion of the left internal carotid artery is seen below the medial cavernous sinus. (C5, C5 portion of the internal carotid artery; CL, clivus; PG, pituitary gland)Fig. 2.20 Opening of the cavernous sinus on the left side.The removal of the medial cavernous sinus wall exposes the C4 portion of the internal carotid artery. (C4, C4 portion of the internal carotid artery; C5, C5 portion of the internal carotid artery; CL, clivus; PG, pituitary gland)Fig. 2.21 Exposure of the internal carotid artery on the left side.The C3 to C5 portion of the internal carotid artery on the left side is well demonstrated. (C3, C3 portion of the internal carotid artery; C4, C4 portion of the internal carotid artery; C5, C5 portion of the internal carotid artery; PG, pituitary gland; NS, nasal septum)Fig. 2.22 Exposure of the medial cavernous wall on the right side.Exposure of the medial cavernous wall on the right side (approach side) is more difficult because the line of the surgeon’s view is tangential. (C3, C3 portion of the internal carotid artery; C4, C4 portion of the internal carotid artery; C5, C5 portion of the internal carotid artery; CL, clivus; PG, pituitary gland)Fig. 2.23 Anatomical relationship between the optic nerve, pituitary gland, pituitary stalk, and internal carotid artery on the left side.The tuberculum sella is removed and the dura above the pituitary gland is opened. The anatomical relationship between the left optic nerve, pituitary gland, and left carotid artery is well demonstrated with minimum retraction of the nasal septum. (C3, C3 portion of the internal carotid artery; C4, C4 portion of the internal carotid artery; C5, C5 portion of the internal carotid artery; Chi, chiasm; NS, nasal septum; ON, optic nerve; PG, pituitary gland; SpP, sympathetic nerve; St, stalk)Fig. 2.24 Anatomical relationship between the optic nerve, pituitary gland, pituitary stalk, and internal carotid artery on the right side.The ipsilateral structures are more difficult to see. (C3, C3 portion of the internal carotid artery; Chi, chiasm; CL, clivus; PG, pituitary gland; St, stalk)Fig. 2.25 (Step 9) Expose the midclivus.By extending our opening in the anterior wall of the sphenoid sinus, the midclivus can be seen. (Ch, choana; CL, clivus; NPx, nasopharynx; NS, nasal septum; PG, pituitary gland)Fig. 2.26 Overview of the final exposure.A low magnification view demonstrates the surgical exposure in the context of the patient’s face. (C3, C3 portion of the internal carotid artery; CL, clivus; NS, nasal septum; PG, pituitary gland; St, stalk)
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