1. Menigiomas on the anterior sagittal sinus are safer to resect than those on the posterior; on the anterior, if you get into the sinus you can ligate it, posteriorly it may lead to mortal bleeding.
2. Sight & Sound: 
- Superior colliculus & Lateral geniculate body- vision
- Inferior colliculus & medial geniculate body  - hearing.
- Brodmann's 41 = primary acoustic cortex.
3. About pain drugs
- morphine 1 = dilaudid 0.2
- morphine is renally cleared
- rigid chest syndrome when bolusing fentanyl (esp kids, anaesthesia dosing rather than analgesic dosing)
- fentanyl patch - steady state 12-24 hours, effect lasts for 14-24 hrs after taking it off
- take off transdermal patches before entering MRI- some have aluminum layer that helps contain the drug and can cause burns
- methadone: half life 15-60 hours (ie can take a long time to reach steady state, as its 5 half lives), can cause QT prolongation
- nalbuphine (nubain): partial agonist/antagonist, 0.05mg/kg pruritis, 0.1 mg/kg analgesia, at doses >0.15mg/kg can reverse opiate effects - don't give in opiate tolerant people
4. Osteoid osteoma vs osteoblastoma:
- Histologically identical. Distinguish by SIZE and BEHAVIOR
- Osteoid osteomas are by definition smaller (<1cm), never have malignant transformation, appear mostly in the lamina of the lumbar spine but occ cervical (not thoracic), can appear in pedicle or facet too, have more bony sclerosis around them, 10% in the spine.
- Osteoblastoma are bigger (>1cm), more locally destructive/invasive, may have contralateral spondylolysis, more often will present with neurologic symptoms, can appear anywhere in the spine, tend to occur in pedicle primarily but frequently multi-part (incl lamina, etc) very rarely will transform into osteosarcoma, about a third will occur in the spine.
- Cure with complete resection - no role for radiation
- Quick word on osteosarcoma- rarely appear in the spine, but when they do, tend to be 40 y/o M with hx of paget's or osteoblastoma.
5. Vertebral hemangioma - 
- most common primary bone malignancy in spine.
- Causes "striped" (sagittal/coronal) or "polka-dot" (axial) or honeycomb vertebral body on CT
- Don't light up on bone scan (vs mets, which do)
- Highly vascular
- Primarily in women post puberty - rarely beforehand, possibly bigger with pregnancy/hormones although this has not been proven.
- Rarely present with sx, and when they do its usually from compression fracture
- Rarely change over time
- Don't do anything unless its symptomatic.
- Small ones tend to be hyperintense on T1 and T2, tend to become hypointense as they grow bigger.
7. Posterior fossa Tumors - ependymoma vs medulloblastoma
- both most common posterior fossa tumors in kids - each about 1/4-1/3, but medulloblastomas more common
- can appear very similar on imaging - somewhat heterogenous, T2 bright, enhancing.
- ependymomas tend to arise from floor of 4th, and medulloblastoma from roof ("medulloblast" thought to be granular cell layer precursors, hence cerebellar)
- if it extends through the foramina of lushka or magendie, it's more likely an ependymoma
- medulloblastomas tend to light up hot on dynamic perfusion MR (dsc-t2) since they are higher grade, while ependymomas (and jpa) are colder.
- maybe ependymomas are a little brighter on dwi/adc... They are hypercellular and so tend to restrict
- other possibly helpful tips that may or may not help - ependymomas sometimes are calcified, some say ependymomas conform to the shape of the 4th while medulloblastomas are rounder.
8. Cystic posterior fossa lesions with mural nodule
- Kid - jpa
- Adult - hemangioblastoma. (Also should make you think of von hipple lindau)
- In the above, the capsule usually doesn't enhance but if it does you need to take it surgically (along w mural nodule).
- enhancing capsule should make you expand differential to include higher grade lesions (mets, gbm)
9. Posterior fossa lesions in adults: most common tumor is met, most common primary is hemangioblastoma
10. CPA Tumors
- 7/9 vestibular Schwannoma aka acoustic neuroma
- 1/9 meningioma
- 1/18 epidermoid cyst (diffusion restricts)