Magic Conference: Treating Cushing’s Disease with Surgery: Ways of Achieving a Cure

MEETING NOTES : Dr. McCutcheon

Meeting Created: July 21, 2012 9:15 AM

Treating Cushing’s Disease with Surgery: Ways of Achieving a Cure

Dr. McCutcheon will discuss the ways of treating Cushing’s disease from the surgical
perspective, including the different ways of getting to the pituitary, the chances of
success, and the potential complications. In addition, special nuances and pitfalls of
surgery in Cushing’s (as opposed to other types of pituitary tumor) will be addressed. 

First, there was a special presentation to Phil.  (image in next post)

Medical and Surgical

Dr. Cushing

Adrenal-pituitary axes in various conditions leading to CS

No one wants to operate on wrong place

CS is too much cortisol, CD is pituitary

Ectopic

Focus on pituitary

Raise cortisol: depression, anorexia, stress, alcoholism, drugs (BCP)

Signs/Symptoms, usual stuff

Pictures of Cushies

Also:

• Body builder who lost weight
• Thin, vigorous woman with small weight gain (10-15 lbs). Looks fine
• Cyclical or mild symptoms.  Many patients.  Symptoms come and go
• Steroids
• Have to be smarter than disease
• Cushing called it polyglandular syndrome
• Cushing depended on autopsy for diagnosis
• Dogs, horses, cats

Most Cushings is pituitary

Measure cortisol

• Am/pm cortisol.  Better at midnight?
• UFC
• Salivary
• Dex (not sex) suppression.  Low dose confirms CS, high dose addresses etiology of cortisol excess
• CRH stimulation
• Petrosal sinus sampling

Circadian rhythm

ACTH

• Half-life is 17 minutes in plasma
• Must cool specimen, add protease inhibitors
• Adrenal:  ACTH down
• Ectopic:ACTH very high
• Pituitary tumor: ACTH nl or up

ACTH-secreting tumors are usually small but visible on MRI

Less than 10% of tumors are large.

Occult tumor

• BiochemicalnCushing's but tumor doesn't show up
• 10% show no tumor during surgery
• Plan for this!
• Tumors of less than a millimeter can cause CD

When tumor is not shown

• Current MRI allows about 95% of tumors to be detected
• Small dark path may be only clue
• Scan is truly normal, surgery may show tumor, hyperplasia or no abnormality

3T is strongest MRI available to public.  9T is available to research

• No evidence that increasing the strength of MRI increases diagnosis in small pituitary tumors
• 3T won't help if tumor didn't show on 1.5T.  Not worse, either
• Dynamic MRI makes scan more sensitive
• Sella protocol
• For dynamic, get contrast while sliding into machine

Petrosal sinus sampling

• Controversial
• 50-70% correct in predicting tumor side.  Same as flipping a coin
• Midline tumors and crossover venous drainage can occur
• Best for actively producing ACTH
• Time of day matter?  Lab has to get samples fast.  Best done in middle of day for staffing
• CRH is now absent in the US so they have to use DDVAP.  Wait until they make CRH again if possible

Aims in management

• Suppression of hormones
• Reduce tumor mass with correction of visual and neurological deficits
• Preserve pituitary function
• Quality of life

Surgery first line unless too risky, or radiation better option

Different ways to get to tumor

• Transnasal, preferred now
• Endonasal
• Sublabial, wider, better angle, more working room, tooth numbness, better for suprasella
• Trans-ethmoidal, on side of eye, angle to target, not many done
• Trans-palate, very big tumor, not standard
• Craniotomy
• Cut side of nose.  Really large tumors

Turbinates (flexible bones) move out of the way usually

Mesh, fat plug

No way to prevent a new tumor that anyone knows

Dr. Hardy, trained Dr IMMC. First to remove microadenoma in 1964. Before that, only large tumors were removed

30-day (yes, DAY) mortality improving since Cushing's day thanks to improvements on many levels

Problems

• Hole in septum
• Loss of sense of smell
• Carotid artery
• Opening too small
• Hurt optic nerve
• Hurt pituitary

find a surgeon who has done 500, if possible

Post op

Endonasal fewer complaints?  Depends on reporting surgeon

Change

• Endoscopic
• Image-guided
• En bloc removal

Advantages of endoscopy

• Smaller opening
• See around tumor
• Reduce nasal complications 

Disadvantages

• Need equipment
• One hand skill
• Hard to learn
• Blood gets in way
• Lack of 3D

Computer-assisted surgery

Trajectory is very important

image guidance as extra scan, use for wandering carotids

Intraoperative MRI

Cushings surgery problems

• Electrolyte
• Hypertension
• Cardiomyopathy
• Obesity makes hard to position
• IV problems
• Bleed more
• Bleeding
• CSF leak

Failure

• Don't find tumor
• Invasion of other areas

Occult tumor

• Cushings but no tumor on MRI
• Small or hyperplasia.
• He moved on too fast to get all this 

Dual-producing tumor or 2 tumors, producing different hormones

Hyperplasia, less well-defined. Hard to get all edges.  Remove more than you think, removing normal gland or remove less and see how patient does