Surgical treatment of nonfunctioning pituitary adenomas.

Small nonfunctioning pituitary (micro)adenomas are encountered frequently as incidental findings. Large (macro)adenomas present with visual compromise, hypopituitarism or headache. Indications for surgery include loss of vision, diplopia, other symptoms of a space occupying intracranial lesion and documented tumor progression during serial imaging. Their primary treatment is surgical resection. To exclude medical treatment options, a preoperative endocrinological investigation is mandatory. To date, more than 90% of operations in patients with nonfunctioning pituitary adenomas are performed via the transsphenoidal route. There are several variations of transnasal surgery available, with and without dissection of the nasal septum. Only tumors where the predominant mass lesion is essentially located outside the sella require transcranial operations. These are usually performed via a frontotemporal or frontolateral craniotomy. Surgical decompression of visual pathways is usually followed by a rapid improvement of vision. Whether or not the tumor mass can be completely resected depends on the size and localization of the adenoma and the surgical expertise. Several patients experience an improvement of pituitary function. Potential complications of surgery include loss of vision, vascular injury, cerebrospinal fluid fistula, meningitis and hypopituitarism. Modern technical developments, such as the use of the endoscope, intraoperative magnetic resonance imaging and neuronavigation, are being increasingly appreciated by neurosurgeons throughout the world.