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1. #Mri of internal auditory canal images which cranial generator
2. #Mri of internal auditory canal images which cranial skin

Identify the labyrinthine segment of the facial nerve at the transverse crest and decompress the meatal foramen a few millimeters.Skeletonize the IAC up the level of Bill\’\’s Bar.Exercise caution when drilling laterally, due to the location of the cochlea and ampulla of the SSCC.Develop your exposure working medial to lateral.Drill deep troughs 270 degrees around the IAC, down to the level of the posterior fossa dura.Lower the meatal plane over the IAC until it is well-defined.The IAC is located 60° anterior to the blue lined SSCC.The Stenvers x-ray will demonstrate the amount of bone overlying the semicircular canal (SSCC).The SSCC will be perpendicular to the petrous ridge.Begin drilling using a 4-0 diamond burr over the arcuate eminence to identify the location of the superior semicircular canal.Place the House-Urban retractor under the lip of the petrous ridge at the anticipated location of the IAC (based upon the arcuate eminence).Brisk bleeding from the middle meningeal artery at the foramen spinosum may be encountered and can be controlled with bone wax and Oxycel packing.Use cottonoids anteriorly and posteriorly for dural retraction during elevation.Identify the arcuate eminence, GSPN, and petrous ridge.Elevate the dura along the floor of the middle cranial fossa from posterior to anterior so as not to disrupt the greater superficial petrosal nerve (GSPN).Place Oxycel cigars under the bone flap anteriorly, posteriorly, and superiorly.Circumferentially elevate the dura from the overlying cranium, using the bipolar cautery liberally to stop bleeding from the dura.Check exposure: if the bone window is not flush with the tegmen, remove excess bone with rongeur or drill.Elevate bone flap off of dural with Joker elevator.Mark bone flap to ensure easy and properly oriented replacement at end of case.Branches of the middle meningeal artery will be encountered, which are controlled with bone wax or bipolar cautery.Use diamond 4 mm burr, to remove the final layer of bone over the dura.Use a 4 mm (BJG) or 5 mm (MRH) cutting burr to remove the majority of the bone.Hyperventilate patient to end tidal CO2 of 30.Have anesthesiologist administer 0.4 grams/kg of mannitol now.Should be able to see zygomatic root easily after elevation.

#Mri of internal auditory canal images which cranial skin

Inferiorly-based temporalis flap if anterior-based skin flap.Anterior temporalis flap if posterior-based skin flap.leave cuff of fascia on either side of muscle flap.Harvest a large piece of temporalis fascia prior to elevation of the muscle flap.Keep temporoparietal fascia layer attached to scalp during skin flap elevation.Temporalis muscle flap is then reflected anteriorly.Incision starts just behind temporal hairline and a rounded box shape approx 6 cm wide is carried back approximately 6-7 cm.Temporalis muscle is then reflected inferiorly.Good for extended middle fossa approaches.Incision starts anterior to tragus, extends posteriorly approximately 3-4 cm posterior to pinna, superiorly 5-6 cm, and anteriorly again to the temporal hairline.Anterior/inferiorly-based skin flap (MH).Also note the posteriorly based temporal skin flap design.

#Mri of internal auditory canal images which cranial generator

Patient positioning with 3 point straps to allow rolling of the bed to improve operative exposureĮlectrode placement NIMS monitor electrodes in the orbicularis occuli and orbicularis oris with ground electrods on the chest ABR click generator in the operertive side ear canal 3 ABR electrodes (one on each mastoid and one on vertex). Nursing instructions to call family every 3 hours White board: intra-operative medications (1 gram Ancef Q8hrs, 10 mg Decadron q6 hrs, Mannitol at 0.4 mg/kg given after performing craniotomy). Pre-operative note, audiogram, ABR test results and Internal medicine surgical co-management note placed on wall