Endoscopic skull base surgery
Terms in this set (10)
Inverted cone-shaped space.
Superior = infraorbital fissure, foramen rotundum, maxillary nerve.
Inferior = greater palatine canal.
Medial = palatine bone, sphenopalatine artery.
Lateral = pterygomaxillary fissure.
Inferior turbinectomy, uncinectomy, and maxillary antrostomy. Then do a total ethmoidectomy and wide sphenoidotomies.
Can partially remove middle turb if needed.
Expose the crista ethmoidalis and SPA foramen by removing mucosa from lateral nasal wall posterior to maxillary antrostomy.
Remove bone of posteromedial maxillary sinus exposing the soft tissue of the PPF
- Superior = greater wing of sphenoid and squamous portion of temporal bone
- Inferior = medial pterygoid muscles attaching to mandible
- Medial = lateral pterygoid plate, lateral part of clivus, lower petrous apex
- Lateral = temporalis muscle, ramus of mandible
- Posterior = tympanic and mastoid portion of temporal bone
- Anterior = Infratemporal surface of maxillary sinus.
Starts the same as approach to PPF. However, posterior maxillary sinus dissection extends to the lateral wall of the maxillary sinus.
Vidian nerve can be found posterior and deep to ligated SPA.
Medial pterygoid plate can be drilled posteriorly and the vidian nerve drilled circumferentially to identify ICA.
V2 is followed posteriorly through the pterygoid bone and PPF.
When pterygoid bone is removed flush with MCF and foramen rotundum, dissection is continued laterally through lateral pterygoid plate.
Access is ideal for CN5 schwannomas, nasopharyngeal cancer, and meningioma
- Medial = posterior border of greater wing of sphenoid.
- Lateral = basilar portion of occipital bone.
- Superior = middle cranial fossa.
- Inferior = carotid canal.
Most common hormone-secreting pituitary tumor accounting for 30% of all pituitary adenomas and 50-60% of functional adenomas.
Normal prolactin level is <25 in females and <20 in males. Abnormal are 100-250 for microadenomas and >250 in macro.
Can be treated medically with dopamine agonists like bromocriptine and cabergoline.
Incidence ranges from 2-7% and is found more commonly in men. Typically seen with adenoma.
Sudden onset HA, N/V, visual changes that persists over a few hours - 3 days.
Treatment = prompt surgical decompression of the pituitary gland. If decompression occurs within 1 week, complete recovery of eye function will occur, but hormonal function may not.
typically arises from the nasal septum and extends to the skull base.
Accounts for 5-15% of skull base tumors.
Slow growing, but locally aggressive.
Treatment = craniofacial resection or endoscopic resection. Better prognosis than chordoma.
Arises from olfactory epithelium. Average age 40yo.
Mets are uncommon, but 10-15% have cervical LAD.
Tx = surgery with XRT. ND if + LAD.
Inlay vs onlay grafts in skull base reconstruction
Inlay = placed between dura and skull base. Can be abdominal fat, acellular dermis, and fascia lata.
Onlay = placed extracranially. Can be avascular, or vascular (pedicled). Vascular flaps have a lower rate of leaks than free grafts.
Supplied by SPA and its posterior septal branch.
Vertical incision is made parallel to the anterior segment of the inferior turbinate.
Two parallel incisions are then made superiorly and inferiorly. Superior incision starts at the sphenoid ostium and is extended anteriorly 1-2cm below the superior edge of the nasal septum.
Inferiorly, carried medially along the posterior choana, down the free edge of the nasal septum, and anteriorly along the maxillary crest.
Rescue nasospetal flap
Can be created if there is a possible but unlikely risk of intra-op CSF leak.
Needs to constantly be retracted and impedes exposure to the floor of the sphenoid. The superior incision is extended 1/3 to 1/2 anteriorly.
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Cleft lip and palate
Embryology of clefts and pouches
THIS SET IS OFTEN IN FOLDERS WITH...
Vestibular and Balance disorders
Thyroid and Parathyroid glands
Congenital hearing loss
Cysts and Tumors of the Jaw