Bilateral Coagulation of Inferior Hypophyseal Artery in Endoscopic Endonasal Transcavernous Approach: Does It Affect Pituitary Function?

Background The endoscopic endonasal transcavernous approach with interdural pituitary transposition provides surgical access to the posterior clinoids and lateral interpeduncular cistern. Prior to performing a posterior clinoidectomy, selective coagulation and transection of the inferior hypophyseal artery (IHA) is recommended to prevent uncontrolled avulsion of the artery from the wall of the cavernous carotid artery. Our preliminary experience has shown that unilateral sacrifice of the IHA has no consequences for pituitary function. The purpose of this study was to evaluate pituitary function in the setting of bilateral posterior clinoidectomies via interdural transcavernous approach with bilateral sacrifice of IHAs.

Methods All patients who underwent endoscopic endonasal bilateral posterior clinoidectomies with bilateral inferior hypophyseal artery sacrifice between March 2010 and December of 2016 were included and retrospectively evaluated. Postoperative assessment of the patient's fluid balance was performed hourly for at least the first 24 hours; serum sodium and urine density were obtained in all patients with increased urine output. Serum cortisol levels and full pituitary panel were evaluated in symptomatic patients with high postoperative risk of pituitary dysfunction.

Results Twenty-two patients had bilateral transcavernous posterior clinoidectomies with coagulation of bilateral inferior hypophyseal arteries and were included in the study. We excluded two cases due to previous pituitary dysfunction. There were 13 chordomas, 3 epidermoid cysts, 2 chondrosarcomas, 1 meningioma, and 1 hemangiopericytoma (6 cases were recurrent). Mean follow-up was 19 months (13–84 months). One patient (hemangiopericytoma) developed persistent (>6 month) diabetes insipidus (DI) and panhypopituitarism requiring long-term treatment with desmopressin, hydrocortisone, and levothyroxine. This patient had a very large and invasive tumor that required not only bilateral sacrifice of IHAs but also extensive surgical manipulation of the pituitary gland. Another patient with an extensive chordoma involving the pituitary gland developed isolated permanent DI. Postoperatively, four patients experienced transient DI requiring one to three daily doses of DDAVP, and in all cases the DI resolved before discharge from the hospital (1–3 days). There were no vascular complications (ICA injury) in this series.

Conclusion The endoscopic endonasal transcavernous approach with bilateral posterior clinoidectomies is a safe and effective approach, when properly executed. In our surgical experience with bilateral sacrifice of the IHAs, the vast majority of patients do not develop any pituitary dysfunction. This finding challenges current understanding of pituitary function and vasculature, suggesting an important role of the superior hypophyseal arteries as compensatory vascular supply for both anterior and posterior pituitary lobes.