Surgery was first used by Horsley in 1889 but was refined by Cushing23. The treatment of choice is either transsphenoidal or transcranial neurosurgical adenomectomy, aiming at complete tumour removal or decompression of surrounding structures. The transsphenoidal approach usually allows for potential resection of a sellar tumour without entering the subarachnoid space, thereby minimizing the risk of complications such as cerebrospinal fluid leakage or meningitis. Complete surgical removal is often impossible, because of the invasive character of microadenomas and larger pituitary adenomas, with infiltration of the neighbouring structures such as arachnoid membrane, dura,
sinus cavernosus and the skull base24,25.
The neurosurgeon’s conclusions on complete resection during operation is dif-ferent from the conclusions on MRI26. This clarifies the statement of Turner et al. who demonstrated that the surgeon’s assessment of complete surgical removal was unrelated to recurrence27. Specialization improves the outcome of pituitary surgery with less morbidity and mortality28. Differences in results among centres for pituitary surgery should be interpreted with caution even for those confined to comparable criteria of remission28. Nowadays minimal invasive neurosurgery i.c. endoscope assisted trans-sphenoidal microsurgery is applied29.
Non-functioning pituitary adenomas are most frequently macroadenomas at
diagnosis. In 90% of the cases, only a partial resection can be performed30.
Concerning prolactinoma, surgery is only rarely performed, in case of resistance or intolerance to medication.
In regard to acromegaly, 75% of the tumours are macroadenomas, which often extends laterally into the cavernous sinus or dorsally to the suprasellar region10. The cure rate with surgery alone for intrasellar lesions is 59-95%21,28 and for larger tumours 26-68%21,28. Intraoperative GH-measurements and intraoperative MRI, can improve results31,32.
For Cushing’s disease, the immediate postoperative cure rate after first surgery for microadenomas varies between 78-97% and for macroadenomas between 50-60%33. After curative resection, the recurrence percentage is 5-25%34.
Although small series have shown, that neurosurgery can improve pituitary hypofunction11,35-38, more often deterioration of the pituitary function will occur30. Other specific side effects of surgery are leakage of cerebrospinal fluids, some degree of nasal discomfort and transient diabetes insipidus or mild SIADH (syndrome of inappropriate vasopressin secretion).
The mortality rate of neurosurgery is reported to vary between 0.26 and 3%39.