الفهرس 
SURGICAL ANATOMY OF THE NORMAL PITUITARYOnly 14 pages are availabe for public view
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Abstract
Pituitary adenomas are relatively common tumors that account for 10 to 20% of all primary intracranial tumors. Epidemiological studies have demonstrated a nearly 20% incidence of pituitary adenoma in the general population. Pituitary adenomas are broadly classified into functioning and non functioning groups passed on the presence or absence of hormone hypersecretion.
Although one of the primary goals of surgery in both groups is to maximize the surgical resection, it is not possible in all times, moreover, functioning tumors may continue to produce significant amount of hormone with deleterious endocrine and systemic effects despite gross total resection adding an additional degree of difficulty to achieving neurosurgical cure. Consequently, rates of long term tumor control using surgery alone vary from 50 to 90% depending on the functional status and degree of tumor invasion.
Our study was conducted on 81 patients harboring residual pituitary adenomas after surgical resection. All the patients were treated by Gamma Knife radiosurgery and had a minimum follow up period of 24 months. Our study included 41 females and 40 males with a nearly equal sex distribution. The age of patients at the time of presentation ranged from 14-72 years with a mean age of 38 years and the maximum follow up period available ranged for 24-108 months with a mean follow up period of 38 months.
Our study included four groups of patients; non functioning adenomas, prolactinomas, Acromegaly, and Cushing’s disease. The results were analyzed in terms of tumor growth control, hormonal (biochemical control), clinical improvement, and visual field changes.
At the maximum follow up period available, tumor shrinkage was achieved in 70% of patients and tumor volume remained stable in 30% of patients. This made the cumulative percent of tumor growth control 100%. There was no significant difference in the rate of tumor volume changes in our four study groups.
At the maximum follow up period available, the rate of hormonal normalization was 68% in prolactinomas, 82% in acromegaly, and 83% in Cushing’s disease. The mean time to hormone normalization was 13 months in prolactinomas, 21 months in acromegaly, and 18 months in Cushing’s disease. Hormonal level normalization was associated with improvement in clinical manifestations due to hormone overproduction.
At the maximum follow up period, complete visual field normalization was achieved in 22% of patients and partial visual field improvement in 47% of patients. This makes the cumulative percent of visual field improvement 69%. Consequently, 5 out of 15 totally blind eyes restored their visual functions and two out of three totally blind patients included in our study had restored their vision.
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Treatment complications included one patient with newly developed hypopituitarism, two patients with newly developed visual field deficits, and one patient with temporal lobe edema. The relatively low complication rates in our study were possibly related to small number of series and short follow up period.
In conclusion, Gamma Knife radiosurgery seems to be a safe and effective therapeutic option for treatment of residual pituitary adenomas after surgical resection. The highly acceptable radiological and hormonal control and relatively low rate of complications at this small follow-up period are consistent with results in literature.
The main limitations of our study were the short follow up period available and shortcomings in the number of patients with completed follow up especially in functioning groups. Therefore, longer follow up period and larger number of patients is required for a better estimate of the rates of tumor control, hormonal normalization, and development of complications.