Preop Meds

• 10 mg IV dexamethasone
• 1 g/kg IV mannitol
• 20 mg IV Lasix
• 2 g Keppra
• 2 g Ancef

Equipment

• Radiolucent Mayfield (for vascular cases, ask attending)
• Layla bar
• Image guidance
  • Mayfield adapter for image guidance to be on the same side as the Mayfield arm
• Microscope

Monitoring

• SSEPs
• Transcranial MEPs
• EMG 7, case dependent, ask attending
• BSERs for contralateral ear

Lumbar Drain

Turn the patient lateral and place a preop lumbar drain.

Patient Positioning

• Turn bed 180 degrees
• Place a large bump longitudinally under the ipsilateral shoulder
• Leave the ipsilateral arm on an arm board, remove the arm board on the contralateral side
• Place a thin piece of purple foam between the contralateral arm and body
• Use 3-inch tape to "burrito" the patient to the bed.
  • Leave the ipsilateral arm out of the papoose for the radial artery harvest
  • Leave the abdomen uncovered for the fat graft site

Pinning

• Double pin on the occiput in the sagittal plane slightly contralateral to midline. 
• Single pin in the forehead (unusual for Lang, I know), in a skin crease, at about the mid-pupillary line. 

Head Positioning

• Rotate the head towards the floor
• Flex the neck
• Drop the vertex of the head
• Attach the Mayfield to the inside attachment, make sure you use the adapter that allows the image guidance to be on the same side
• Attach the Layla bar attachment on the contralateral side (i.e. by the patient's face)

Arm Positioning

For the radial artery interposition graft: 

• Keep the arm on the arm board, but swing it out away from the bed by about 20 degrees
• Pad the underside with plenty of thin purple foam. The arm will float a little because of the shoulder bump and you want to liberally support it with foam. 
• Use 3-inch tape to secure the hand to the arm board

Marking

For the head, start the incision ~1 cm anterior to the tragus to ensure that the root of the zygoma will be exposed. Curve over the ear, about 3 cm posterior to the auricle, then down to the mastoid tip. 

For the radial artery, use the Doppler to mark the course of the distal radial artery. You will lose the Doppler signal more proximally when the artery dives deep to the brachioradialis muscle. To draw the rest proximal portion of the incision, palpate the interval between the biceps tendon and brachioradialis muscle in the antecubital fossa and connect this point with the course of the artery determined by Doppler ultrasound. 

Draping

• Ioban on all three incisions
• Thyroid drape over abdominal fat graft site
• U-drape over radial artery graft site, with the horizontal leg of the U at the wrist and the vertical limbs extending along the arm towards the head
• Craniotomy drape over the head with the bag pointed towards the occiput

Approach

Open the skin with a #10 scalpel blade. Go through dermis and subcutaneous fat. 

Use double-wide skin hooks to elevate the skin edge then use the Bovie to develop the plane between the galea and the fascia of the muscle (temporalis anteriorly and trapezius and sternocleidomastoid posteriorly). 

Use the Bovie to cut through the fascia and muscle straight down to bone. Leave about a 2-cm cuff of muscle between the muscle cut and the skin incision. The muscle cut is a deep arc that connects the tip of the mastoid and the root of the zygoma. 

Elevate the muscle from the bone with a combination of Bovie and blunt dissection. As you proceed inferiorly, the temporal bone begins to slope towards the EAC. There is a characteristic spine of bone just before you encounter the opening of the EAC called the spine of Henle. 

Closure