15 Frontotemporal and Pterional Approach • Aneurysms. ◦ All aneurysms of anterior circulation. ◦ Basilar tip aneurysms. • Parasellar lesions. • Meningiomas involving the sphenoid wing and the anterior clinoid. • Position: The patient is positioned supine with torso flexed slightly downward and knees slightly flexed to improve venous drainage. Soft gelatin roll placed under the ipsilateral shoulder can be used to reduce neck rotation. • Head: The head is fixed in a Mayfield 3-point head holder. It is rotated to contralateral side such that the pterion area is at 12 o’clock, elevated and slightly extended so that the vertex tilts toward the floor. • The ipsilateral zygoma is the highest point in the surgical field. • The single pin of the head holder should be placed on the ipsilateral side superior to the mastoid process. On the other arm, one pin is placed superior to the mastoid process on the contralateral side. • Starting point: The incision begins at the zygoma (1 cm anterior to the tragus to avoid damage to frontotemporal branch of facial nerve and frontal branch of superior temporal artery). • Run: The incision extends cephalad crossing the superficial temporal artery while coursing posterior to the hairline. • Ending point: The incision terminates at widow’s peak. • The base of the skin incision should equal its height to avoid necrosis of the margin. Hemostatic clips are attached to skin edge and galea to keep vascularity. • The superficial temporal artery is preserved in every case, especially if the surgeon anticipates the potential for bypass. • Frontal branch of the facial nerve. • Superficial temporal artery. • Myofascial level (Fig. 15.2) ◦ Yasargil first described the interfascial dissection of the temporal muscle that serves to preserve the frontotemporal branch of the facial nerve and minimize postoperative cosmetic changes (see Chapters 6 and 8). Fig. 15.1 Skin incision. The incision begins at the zygoma, 1 cm anterior to the tragus and extends cephalad posterior to the hairline ending at the widow’s peak. Fig. 15.3 Temporal muscle detachment. The temporal muscle is elevated away from the squamous portion of the temporal bone and is reflected in the same manner as the skin flap. A small cuff of fascia is left along the superior temporal line. ◦ The temporal muscle is covered by a superficial fascia. This dissection should be made vertically starting from the superior temporal line, 1.5 to 2 cm from the superior rim of the orbit to the posterior portion of the zygomatic arch using a cold scalpel and Metzenbaum scissors. ◦ The reflection of the skin and superficial fascia along with its underlying fat pad is completed with the use of hooks or sutures and elastic bands as per surgeon’s preference. • Muscles (Fig. 15.3) ◦ The dissection and detachment of the temporal muscle is done in two stages. A vertical incision is made perpendicularly to the zygoma posteriorly and a transverse incision parallel to the superior temporal line, leaving a superior strap attached to the skull.
15.1 Indications
15.2 Patient Positioning
15.3 Skin Incision (Fig. 15.1)
15.3.1 Critical Structures
15.4 Soft Tissue Dissection
Abbreviations: E = ear; FB = frontal bone; PC = pericranium; STL = superior temporal line; TM = temporal muscle; TSq = temporal squama.
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