Bilateral Nasoseptal Rescue Flap with Olfactory Epithelium Preservation: A Prospective Study Analyzing Postoperative Olfaction and Epistaxis

Background: Adequate exposure and preservation of normal sinonasal function remain key but often competing goals in endoscopic skull base surgery. We have previously published our approach and rationale for utilizing bilateral nasoseptal rescue flaps. Herein, we report a prospective study to determine if this approach impacts the incidence of postoperative epistaxis and olfactory dysfunction.

Methods: A prospective analysis was performed for patients who underwent endoscopic endonasal skull base surgery between February 2012 and August 2014. Patients were classified by diagnosis, the approach (simple, extended and/or revision), and the four types of mucosal flaps elevated (bilateral nasoseptal “rescue flaps,” converted NSF from “rescue flaps” planned nasoseptal flaps [NSF], or middle turbinate flap [MTF]). The incidence of postoperative hyposmia, anosmia, and epistaxis were analyzed. All patients underwent olfactory testing utilizing the Brief University of Pennsylvania Smell Identification Test (B-UPSIT) at baseline preoperatively and postoperatively at 6 weeks and subsequently.

Results: In total, 164 patients, 92 female and 72 male participants with a mean age of 50 years, were enrolled in the study. Overall, 102 patients completed the olfactory outcomes study. Pathologies of the 164 patients included 121 pituitary adenomas (44 functional and 77 nonfunctional), 16 Rathke cleft cysts, 8 meningiomas, 7 craniopharyngiomas, 3 arachnoid cysts, and 9 other pathologies. Of the 164 patients, 86 patients had a simple approach with 78 having extended approaches beyond the sella. Overall, 29 (18%) patients underwent revision operations. Bilateral nasoseptal “rescue” flaps were elevated in 152 patients (94%). Five patients were converted from the rescue flap to a formal nasoseptal flap. Twelve patients had planned nasoseptal flaps, and three patients had a middle turbinate flap reconstruction with rescue flap procedure. Bilateral nasal septal “rescue flaps” were used in 131 patients (96%) of pituitary adenomas and Rathke cleft cysts.

In each operation, excellent visualization and mobility of the endoscope, and dissecting instruments were experienced with no alteration of the approach. In “rescue flap” procedures, the sphenopalatine artery pedicle was preserved. Postoperatively, there were no episodes of posterior epistaxis or return to the operating room for epistaxis. Olfaction analysis in 102 patients demonstrated preservation of normal function in 79 patients, 8 patients demonstrated preoperative abnormal function to postoperative normal function (87/92 normal post-op olfaction, 95%), 5 patients (5.0%) with mild hyposmia without anosmia, and 10 patients with abnormal preoperative and postoperative olfactory function who were not included in the olfaction outcomes analysis. On the basis of absolute B-UPSIT scores, 21 patients (21%) showed improved olfactory function after surgery. None of the 11 patients who had a vascularized flap skull base reconstruction (NSF or MTF) had postoperative smell dysfunction including one patient who recovered normal olfaction from a preoperative deficit.

Conclusion: Septal olfactory strip preservation during elevation of bilateral nasoseptal “rescue” flaps and the NSF is an effective mucosalsparing and olfactory function preserving approach applicable for the majority of endonasal endoscopic pathologies. In addition, by preserving the vascular pedicle (sphenopalatine artery), this approach appears to largely eliminate the risk of major postoperative epistaxis and allows for future conversion to nasoseptal flaps.