Donald P. Becker, M.D.
Figure 1: Patient position for transsphenoidal approach.
The transsphenoidal approach is the procedure of choice for the removal of tumors of the sella that are still largely confined to this space. It is also indicated for removal of some tumors of the parasellar area. Pituitary tumors with substantial intracranial extension can engulf important structures and should be treated using a transcranial approach.
For transsphenoidal surgery, there are several alternative approaches to the sphenoid sinus. These include the transnasal paraseptal, sublabial-transseptal, and paranasal transethmoidal approaches. For processes that are largely located in the sella, the sublabial or trananasal approach is used. With extreme involvement of the paranasal sinuses, the paranasal transethmoidal exposure is of benefit.
Martin N. Montoro, MD, and Jorge H. Mestman, MD
Changes In The Normal Anterior Pituitary Gland During Pregnancy
Anatomic and functional changes take place in the pituitary gland during pregnancy that have to be taken into consideration to properly evaluate its function, and particularly to diagnose pituitary disorders during pregnancy.
The various anterior pituitary hormonesprolactin (PRL), thyroxine-stimulating hormone (TSH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH), corticotropin (ACTH), and growth hormone (GH) are released into the systemic circulation in response to stimulating or inhibiting messages from hypothalamic peptide hormones. These peptides reach the pituitary gland through the portal circulation. Thus far several have been identified; they include thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone GnRH), corticotropin-releasing factor (CRF), growth hormone-releasing factor (GHRF), somatostatin (somatotropin release-inhibiting factor [SRIF]) and more recently, a GnRH-associated peptide (GAP) that inhibits prolactin secretion. Dopamine, a biogenic amine, also inhibits PRL secretion. Communications between the hypothalamus and the higher centers of the brain are accomplished by a variety of neurotransmitters, which include the already mentioned dopamine, serotonin, y-aminobutiric acid (GABA), norepinephrine and various opioid peptides, as well as many of the peptides also found in the intestinal tract.
Predictors of Outcome and Long-Term Results
The February, l999 issue of the journal Neurosurgery contains a report by Tyrrell and colleagues from the University of California in San Francisco (UCSF) in which early outcomes and long-term results are analyzed in a large series of patients with prolactinomas following transsphenoidal microsurgery. Two groups of patients treated in different periods of time were followed, and outcomes including complications were evaluated to provide information on the benefits and risks of microsurgery in the management of prolactinomas. The author, J. Blake Tyrrell, is Professor of Medicine and Head of the Section of Endocrinology at UCSF. All patients were operated on by Charles B. Wilson, Professor of Neurosurgery at UCSF. The statistical analysis was performed by Kathleen R. Lamborn, also at UCSF.
Clinicopathological Features and Long Term Outcome Following Transsphenoidal Resection
Gordon Tang (Barstow, CA), Ming-Ming Ning, Marielle H. Nyugen, Brooke Swearingen, Nicholas T. Zervas (Boston, MA)
Discussant: Kalmon Post
Endocrine-inactive adenomas (EIA) account for 30% of pituitary tumors but are infrequently studied. We aim to characterize their clinical presentation, identify endocrinological and radiographic features, study pathological characteristics and determine long-term outcome. We have therefore retrospectively reviewed the cases on 357 patients who underwent resections of EIA from 1978 to 1996 with an average follow up of 8.4 years.