Transsphenoidal hypophysectomy is a commonly used surgical approach for pituitary region masses, with many significant advantages over open craniotomy.
The transsphenoidal approach was first described in 1907 by Schloffer, modified by Halstead and subsequently popularised by Harvey Cushing, who is most associated with this technique 2. It is interesting to note that towards the end of his career Cushing abandoned transsphenoidal surgery in favour of a subfrontal approach 2-3.
Transsphenoidal surgery is indicated in many pituitary region tumours, including:
- pituitary adenomas
- pituitary microadenomas
- pituitary macroadenomas provided they are mostly midline
- craniopharyngiomas (provided they are intrasellar)
- biopsy of midline sphenoclival lesions (e.g. chordoma, aspergilloma, meningioma etc..)
- debulking of larger tumour
It is important to note that the size of the suprasellar component is not terribly important, and tumour can be delivered down into the pituitary fossa from as high up as the foramen of Monro 1. This can be aided by valsalva manoeuvre or introduction of air of sterile saline via a lumbar drain.
The main limitation of the transsphenoidal approach is that the the operative corridor is narrow and lateral tumour is difficult to resect. As such tumours with large parasellar component should be tackled transcranially if a total resection is being aimed for 1.
It is beyond the scope of this article to go into operative details, and only a brief summary is provided, at a level useful to a radiology audience 1.
- general anaesthesia
- patient is placed semi sitting in Mayfield tongs
- intra-operative fluoroscopy is used to confirm instrument positioning
- operative microscope is used
- incision in the buccal mucosa under the upper lip
- blunt submucosal dissection along the nasal septum to the sphenoid sinus
- speculum inserted
- anterior wall of the sphenoid sinus is opened
- mucosa of the sphenoid sinus is removed from the posterior wall
- anteroinferior wall of the pituitary fossa is opened
- the dura is opened
- tumour is removed with a variety of instruments (e.g. pituitary rongeurs)
- the surgical defect is packed with fat
- anterior wall of the fossa reconstituted with bone / cartilage / glue etc...
- further fat packing
- nose is packed with Vaseline gauze impregnated with Bacitracin ointment
- lip incision closed
Recently endoscopic techniques have also been developed.
- postoperative haemorrhage presenting similarly to pituitary apoplexy
- CSF leak which may result in meningitis
- 1. Sekhar LN, Oliveira ED. Cranial microsurgery, approaches and techniques. George Thieme Verlag. (1999) ISBN:0865776989. Read it at Google Books - Find it at Amazon
- 2. Laws ER, Sheehan JP. Pituitary surgery, a modern approach. S Karger Ag. (2006) ISBN:3805580517. Read it at Google Books - Find it at Amazon
- 3. Cohen-Gadol A, Spencer D. The Legacy of Harvey Cushing, Profiles of Patient Care. TNY. (2007) ISBN:1604066318. Read it at Google Books - Find it at Amazon