Olfactory improvement in acromegaly after transnasal transsphenoidal surgery

The direct transnasal transsphenoidal approach to the sellar region has become a widely adopted surgical procedure among neurosurgeons and ear, nose, and throat specialists. Nasal complications and their incidence have been investigated, but a systematic testing of olfactory disturbance has not previously been performed. Considering that the sense of smell is deeply anchored and interwoven within the CNS, and that its impairment implies a considerable loss in quality of life, surgical practice should aim at its preservation.

In this retrospective study, pre- and postoperative olfactory performance, nasal airway passage, septal perforation, and epistaxis were assessed in 96 patients who underwent direct transnasal transsphenoidal microsurgery at the authors' department between January 2007 and August 2009. Olfactory performance was assessed using the Sniffin' Sticks test and/or the Zürcher Geruchstest.

After surgery, 47 (49%) of 96 patients improved, 34 (35%) of 96 deteriorated, and 15 (16%) of 96 presented with unchanged olfactory performance. With respect to the underlying pathological entity, the authors noticed a remarkable difference between patients with acromegaly (23 cases) and all other patients (73 cases). Fifteen (65%) of 23 patients with acromegaly improved (others 44%), only 3 (13%) of 23 deteriorated (others 42%), and 5 (22%) of 23 remained unchanged (others 14%) in their ability to distinguish odors. This illustrates a significant shift toward improved postoperative olfactory performance (cross-tabulation, Fisher exact test; p = 0.028) in patients with acromegaly. In nasal breathing, 77 (80%) of 96 patients noticed no change, 11 (12%) of 96 improved, and 8 (8%) of 96 worsened postoperatively. Of the 11 patients with improved breathing, 6 (55%) had acromegaly. Improved nasal airway patency was more frequent in patients with acromegaly (cross-tabulation, Fisher exact test; p = 0.002).

The data provide the first significant evidence for improvement in olfactory performance in patients with acromegaly after transsphenoidal surgery (TSS) of growth hormone-producing adenomas. Furthermore, postoperative olfactory disturbance in patients treated with transnasal TSS is more frequent than previously reported. Nevertheless, recurrent transnasal TSS can be performed successfully, even multiple times, and does not involve a higher risk of nasal complications.