Monitoring

• SSEPs
• EEG
• tcMEPs

Pinning

Always use the radiolucent head holder.

Body position

Supine on a flat table. Ipsilateral arm tucked. Contralateral arm out towards anesthesia. Liberally tape the patient to the bed. 

Be sure to leave the right groin bare in case of need for intraoperative angiography.

Head position

• Extend the neck, a lot. This helps the frontal lobes fall away from the floor of the anterior cranial fossa
• Rotate the head 60 degrees to the contralateral side

Incision

Curvilinear incision beginning 1 cm anterior to the tragus and following the hairline to the midline. 

Prep once and administer local anesthetic. 

Setup

Greenburg retractor oriented in a standard Zenonos pentagon. 

Approach

Go through skin and subcutaneous fat with a 10 blade. Do not go through the galea. 

Use a toothed Gerald pickup to pick up the cut edge of skin and poke through the galea with the closed tips of a pair of Metzenbaum scissors. Develop the subgaleal plane and cut through just the galea with the scissors. Do not go through the pericranium. 

At the bottom of the incision (i.e. by the ear) spread with the scissors to identify and preserve the STA. 

Place Raney clips along the incision. 

Pick up the skin edge and use a 15 blade to dissect in the plane immediately deep to the galea, leaving the pericranium down on the skull (above superior temporal line) and temporalis muscle (below superior temporal line). 

Carry this dissection anteriorly to the orbital rim and use a broad periosteal to get down onto the bone of the rim. No need to extensively dissect it for an acomm. 

Place fish hooks to retract the skin flap anteriorly. 

Pericranial flap

In the case of a large frontal sinus that may be violated in the course of turning the craniotomy, you will want to raise a pericranial flap as a contingency. Use a Bovie to make a cut in the temporalis parallel to and below the superior temporal line, leaving a small cuff of fascia at the line. The cut begins at the orbital rim and extends posteriorly to a few millimeters shy of the edge of the skin incision. When the cut reaches its posterior limit, curve it down towards the zygoma parallel with the posterior part of the skin incision. This inferiorly-oriented cut extends only for 3 cm or so and does not need to reach the bottom of the incision or expose the zygoma. 

Use the Bovie to make an incision in the pericranial flap above the superior temporal line then elevate it. The pericranial flap is pedicled anteriorly (i.e by the orbit). The first cut is parallel to and above the superior temporal line. Once this cut reaches the posterior limit of the skin incision, it is curve upwards towards the top of the head, paralleling the skin incision, then is extended anteriorly to the anterior limit of the exposure. Next, use a Love-Adson periosteal dissector to elevate the pericranium, cover it with wet Telfa, and tuck under the anteriorly-retracting skin hooks.