Should ENT surgeons undertake pituitary surgery ?

Pituitary surgery was first carried out at the turn of the century. Victor Horsley in his address to the 74th Annual meeting of the British Medical Association, published in 1906, made brief reference to 10 cases he had operated upon by what is assumed to have been a sub-temporal approach. Schloffer published an article in 1907 describing a per nasal trans-sphenoidal operation and in 1909 Oskar Hirsch described his per nasal technique based on the work of Hajek. This operation, which was performed under local anaesthetic, was carried out in four stages over a period of four days. In 1912 Harvey Cushing published his work on pituitary surgery in which he further refined the per nasal approach. This differs very little from the technique used by most surgeons to this day. It was Cushing who proposed that tumours with a significant supra sella extension should be treated by a trans-cranial rather than a trans-sphenoidal route, although there is some evidence to suppose that Cushing reverted to the trans-cranial route as his main approach towards the end of his career. Dott learned the Cushing trans-sphenoidal technique from the master and continued its use for the decompression of pituitary tumours throughout his career in Edinburgh. He, in turn, passed it on to Guillot who practised in Paris. In the late 1960s Jules Hardy learned the technique from Guillot and is rightly credited for popularizing the operation and for introducing the use of the operating microscope. In the early 1960s, Angel-James described the trans-ethmoidal approach to the pituitary, in response to an increasing demand for pituitary ablation in the context of advanced metastatic carcinoma of the breast. At this time it was known that some metastatic breast disease responded to oestrogen ablation. Until then, it had been the practice to carry out bilateral adrenalectomies and oophorectomies. It was felt to be more humane, however, to carry out oestrogen ablation by removal of the pituitary. Angel-James' technique was adopted by a number of ENT surgeons, notably Salmon, Richards and Williams, and whilst the initial results were disappointing as compared with neurosurgical trans-frontal pituitary ablation of the day, within two years the results were comparable, regardless of the approach. With the discovery of Tamoxifen, the need for this kind of ablative surgery in the management of breast carcinoma disappeared. Prior to the early 1970s, pituitary surgery had largely consisted of ablation of the gland or decompression of tumours. With the advent of radioimmunoassay and the adoption of the operating microscope, Hardy was able to show that hormonesecreting adenomas of the pituitary could be removed, leaving normal gland behind. This line of succession from Cushing through to Hardy was entirely in the hands of neurosurgeons. A few ENT surgeons continued to use the transethmoidal approach under microscopic control for the removal of hormone-secreting pituitary adenomas. The majority of the ENT surgeons who still practise in this field today adopt the Angel-James trans-ethmoidal approach, rather than the midline trans-septal route. On an international basis, nowadays pituitary surgery is carried out predominantly by neurosurgeons, using a trans-nasal approach, either per nasal or through a sub-labial incision. It has been suggested that functional endoscopic sinus surgery may have a role to play, though it is unlikely to displace the present techniques in the foreseeable future. The use of real time magnetic resonance imaging may influence surgery of this kind in the future but for the moment it is beyond the financial reach of most UK departments. The 1994-95 figures for the incidence of pituitary surgery in the UK indicate that some 317 cases were performed in that year. It is assumed that the bulk of this work was undertaken by neurosurgeons via a trans-sphenoidal route, although some will have used the trans-frontal approach. The remainder will have been carried out by ENT surgeons. Damage to the carotid arteries represents the major hazard in pituitary surgery. It is essential, therefore, to be able to identify the midline at the time of opening of the pituitary fossa. The major disadvantage with a trans-ethmoidal approach, is the difficulty in accurately identifying the midline. The midline approach allows for clear identification of the posterior end of the nasal septum, which always lies in the midline, and acts as an indicator of the point at which the pituitary fossa should be entered, regardless of the anatomy of the sphenoid which is notoriously variable. This technique, taken in conjunction with the use of the image intensifier, renders the midline approach substantially safer than the trans-ethmoidal route.