Mr Michael Powell
National Hospital for Neurology and Neurosurgery

Most people with a Pituitary tumour will require surgery. Of course, Radiotherapy and medical therapy are also important in pituitary management, and not every case requires surgery (eg many prolactinomas), but still, many people will require an operation. To do this, we have to use a route to get to the Pituitary gland either through the skull cavity under the brain or through the back of the nose, via the air cavity called the sphenoid sinus.

I shall highlight three developments here: endoscopy, image-assisted surgery, and new skull-based approaches to the pituitary. Before I do so, I would like to touch on the risks associated with pituitary surgery, which are the reason we need to look for improved techniques.

One risk is damage to the function of the normal part of the gland, although sometimes, of course, it is damaged before we get there. We obviously need to avoid damaging the optic nerves, which may well be compressed as part of the reason why a surgeon is required in the first place. There are three particular dangers that should be avoided by surgeons and can be avoided with training, experience and careful study of such things as the scan details of the anatomy. The first error is opening the carotid artery; the second is opening the bone at the back of the pituitary and biopsying the brain stem, which is usually fatal; and the third error is when the surgeon misses the pituitary gland altogether and biopsies normal brain. All of these are avoidable tragedies.

To move on to the new approaches I mentioned earlier, the first of these is endoscopy. An endoscope is a long thin tube of metal with some clever optics, which can be inserted into body cavities and has a remote light source that is brought through a cable. The image is taken to a camera, so that what is seen at the endoscope can be followed during the operation. Some endoscopes look straight ahead and some are angled at 30°. I use them in something called endoscope-assisted surgery. Most of the operation is carried out normally, but the endoscope is used to help me at the end.

Use of a 30° endoscope provides side views, allowing the study of the side wall of the pituitary fossa and the cavernous sinus, which the carotid artery runs in. It helps us make sure that we have taken away the extension of the tumour sideways, which has previously been difficult. This will hopefully improve endocrine results of surgery. It also allows, to a certain extent, a view of what is going on up above, although I do not think that it is always needed.

Totally endoscopic procedures lessen the need for nasal dissection, although the down side is that the surgeon does not have the same freedom of movement. The surgeons who use it would argue that there is a shorter patient stay, although I personally keep patients in for endocrine testing after their surgery and that is what normally keeps them in hospital, rather than an actual need to be in hospital because of the operation.

The next thing I wanted to talk about was neuronavigation, or image-directed surgery. MRI (magnetic resonance imaging) scans are taken before the operation, and we have to interpret what they show by what we see. With neuronavigation, a computer links a pointer, which we have in our hands during the operation, with what we see down the microscope, and this can be integrated with a computer image on the scan. By this method, we know exactly where we are in relation to the scan and we can therefore know the exact location of vital structures such as the carotid artery, the clivus, and the optic nerves and their canals in the skull base. This sort of device is now available in a number of neurosurgical units in the UK, and I think that before very long it is going to be in every neurosurgical unit, although they are quite expensive.

I mentioned before that there are some new transcranial approaches. These are approaches that actually go through the skull cavity and involve lifting up brain. Most people who have had craniotomies will have had a classic subfrontal, which is through the front, or pterional, which is just in front of the temple. These are the approaches we were taught as registrars, but we have been experimenting and have found two extremely useful ENT approaches. These are the glabella approach and the rather gruesome-sounding mid-face facial degloving, which is useful for very difficult and extensive skull-based pituitary tumours. The transglabella is the most useful (the glabella is the bone between the eyebrows). Because there is little or no disturbance of the brain, it is particularly well tolerated in elderly patients and it has been used successfully in patients in their late 70s and 80s.

I would like to leave you with a thought about what I think is going to happen in the future. I think that pressure groups like The Pituitary Foundation are going to demand designated pituitary surgeons. They could be either neurosurgeons or ENT surgeons, but there is no doubt that dedicated pituitary surgeons will increase the level of experience and therefore improve results. Not only is that going to improve results, both in terms of endocrine function and of ophthalmic recovery, but it will also reduce the risks of surgery. It will allow safe utilisation of new technology, improved training and, through collaborative work with people like Stafford Lightman, it will assist further research into the understanding of pituitary disease.