====== Petrosal craniotomy ======



===== Indications =====

1. lesions of the petrous apex (e.g. petroclival meningiomas)

2. lesions of the clivus (e.g. chordomas) with both posterior fossa and supratentorial components

=====  Advantages =====

Spares sinus and otologic apparatuses. Minimizes cerebellar and temporal lobe retraction.

===== Technique =====

see [[Petrosal approach]].

===== Position =====

1. patient supine, ipsilateral shoulder roll

2. elevate thorax 10°: reduces venous distension

3. flex knees

4. Mayfield 3 pin head-holder: close to true AP with single pin on forehead

5. head positioned to place petrous base at highest point of field:

a) head rotated 40–60° from vertical

b) head abducted towards contralateral shoulder

c) neck extended 15°: allows gravity to retract frontal lobe away from skull base

===== Skin incision =====

Reverse question mark starting from zygomatic arch 1cm anterior to tragus, arcing posteriorly over
ear, descending to 0.5–1cm medial to mastoid notch.

Temporalis muscle and periosteum reflected anteriorly and inferiorly.

===== Craniotomy =====

Four burr holes are utilized, two on each side of the sinuses (near the junction of the transverse and
sigmoid sinuses).