Pituitary Surgery: What You Need To Know?

Endocrine complications

DI and anterior pituitary insufficiency were the most frequent complications reported in the national survey. With the least experienced surgeons, one of five transsphenoidal operations resulted in both of these complications. In contrast, the incidence of these complications was lower in the hands of the most experienced surgeons.

Figure 11Postoperative anterior pituitary insufficiency has been reported in the literature as being rare (72). Various series cite an incidence ranging from less than 1 to 10% (63, 97,101), with one series reporting an incidence of 27% (82). Postoperative anterior pituitary insufficiency was also reported to occur more frequently after removal of larger tumors and in patients whose anterior pituitary functions were impaired pre-operatively (63).The residual normal anterior pituitary tissue can be identified in the preoperative, T1-weighted, infused magnetic resonance imaging scans as a thin layer of enhanced tissue draping around the tumor,mostly over the upper pole of the tumor (Fig. 11). Every effort should be made to preserve this attenuated, residual, normal anterior pituitary tissue, because it can prove sufficient to maintain or even improve anterior pituitary functions in the postoperative period (64).

Temporary post-transsphenoidal surgery DI has been reported to occur in 10 to 60% of cases (26, 68, 82). Permanent DI, however,seems to be relatively rare, with the reported incidence ranging in most large series from 0.5 to 15% (8, 26, 44, 52, 61, 68, 71,97,101). DI after removal of microadenomas usually occurs as a consequence of stalk manipulations. Vertically oriented vessels on the pale-reddish stalk are helpful landmarks for recognizing the stalk. In pituitary macroadenomas, the stalk and the posterior lobe are often not seen because they can be displaced in any direction, flattened, and covered by a fibrous layer. The latter finding explains the relatively low incidence of permanent postoperative DI in patients undergoing removal of pituitary macroadenomas.

In addition, the postoperative course can be complicated by inappropriate secretion of the antidiuretic hormone, which occurs usually on the 6th or 7th postoperative day and thus frequently after the patient has been released from the hospital (5,15,19,95, 97). One of the explanations for this phenomenon is presumed necrosis of a portion of the posterior lobe because of surgical trauma, resulting in a sudden release of the antidiuretic hormone.