Protocol for postmortem bedside endoscopic procedure to sample human respiratory and olfactory cleft mucosa, olfactory bulbs, and frontal lobe.

We present a protocol for the rapid postmortem bedside procurement of selected tissue samples using an endoscopic endonasal surgical technique that we adapted from skull base surgery. We describe steps for the postmortem collection of blood, cerebrospinal fluid, a nasopharyngeal swab, and tissue samples; the clean-up procedure; and the initial processing and storage of the samples. This protocol was validated with tissue samples procured postmortem from COVID-19 patients and can be applied in another emerging infectious disease. For complete details on the use and execution of this protocol, please refer to Khan et al. (2021)1 and Khan et al. (2022).2.

Biopsy of the olfactory epithelium from the superior nasal septum: is it possible to obtain neurons without damaging olfaction?

INTRODUCTION: Olfactory epithelium biopsy has been useful for studying diverse otorhinolaryngological and neurological diseases, including the potential to better understand the pathophysiology behind COVID-19 olfactory manifestations. However, the safety and efficacy of the technique for obtaining human olfactory epithelium are still not fully established. OBJECTIVE: This study aimed to determine the safety and efficacy of harvesting olfactory epithelium cells, nerve bundles, and olfactory epithelium proper for morphological analysis from the superior nasal septum. METHODS: During nasal surgery, 22 individuals without olfactory complaints underwent olfactory epithelium biopsies from the superior nasal septum. The efficacy of obtaining olfactory epithelium, verification of intact olfactory epithelium and the presence of nerve bundles in biopsies were assessed using immunofluorescence. Safety for the olfactory function was tested psychophysically using both unilateral and bilateral tests before and 1 month after the operative procedure. RESULTS: Olfactory epithelium was found in 59.1% of the subjects. Of the samples, 50% were of the quality necessary for morphological characterization and 90.9% had nerve bundles. There was no difference in the psychophysical scores obtained in the bilateral olfactory test (University of Pennsylvania Smell Identification Test [UPSIT®]) between means before biopsy: 32.3 vs. postoperative: 32.5, p = 0.81. Also, no significant decrease occurred in unilateral testing (mean unilateral test scores 6 vs. 6.2, p = 0.46). None out of the 56 different odorant identification significantly diminished (p > 0.05). CONCLUSION: The technique depicted for olfactory epithelium biopsy is highly effective in obtaining neuronal olfactory tissue, but it has moderate efficacy in achieving samples useful for morphological analysis. Olfactory sensitivity remained intact.

Neural Stem/Progenitor Cells of Human Olfactory Mucosa for the Treatment of Chronic Spinal Cord Injuries.

We studied the efficiency of transplantation of neural stem/progenitor cells from human olfactory mucosa in chronic spinal cord injury. Neural stem/progenitor cells were obtained by a protocol modified by us and transplanted to rats with spinal post-traumatic cysts. It was shown that transplantation of neural stem/progenitor cells from human olfactory lining improved motor activity of hind limbs in the recipient rat with spinal post-traumatic cysts (according to BBB scale).

Safety and efficacy of superior turbinate biopsies as a source of olfactory epithelium appropriate for morphological analysis.

PURPOSE: There is no standardized approach for preserving olfactory function in the side of the nose where biopsy of the olfactory epithelium (OE) is performed. Moreover, a gold standard technique for obtaining human OE in vivo is still lacking. We determined the efficacy of obtaining good-quality OE specimens suitable for pathological analysis from the lower half of the superior turbinate and verified the safety of this procedure in maintaining bilateral and unilateral olfactory function. METHODS: In 21 individuals without olfactory complaints and who had undergone septoplasty and inferior turbinectomy OE biopsy was made during septoplasty. Olfactory function, both unilateral and bilateral, was assessed using the University of Pennsylvania Smell Identification Test (UPSIT) before and 1 month after the procedure. Specimens were marked with the olfactory marker protein for confirmation of OE presence. RESULTS: Ninety percent of the samples contained OE, although clear histological characterization was possible from only 62%. There was no deterioration of UPSIT scores either bilaterally or unilaterally on the side of the biopsy. Patients also maintained the ability to identify individual odorants. CONCLUSION: Biopsies of the lower half of the superior turbinate do not affect olfactory function and show strong efficacy in yielding OE tissue and moderate efficacy for yielding tissue appropriate for morphological analysis. Future studies are needed to assess the safety of this procedure in other OE regions.

In Vivo Inspection of the Olfactory Epithelium: Feasibility of Robotized Optical Biopsy.

Inspecting the olfactory cleft can be of high interest, as it is an open access to neurons, and thus an opportunity to collect in situ related data in a non-invasive way. Also, recent studies show a strong link between olfactory deficiency and neurodegenerative diseases such as Alzheimer and Parkinson diseases. However, no inspection of this area is possible today, as it is very difficult to access. Only robot-assisted interventions seem viable to provide the required dexterity. The feasibility of this approach is demonstrated in this article, which shows that the path complexity to the olfactory cleft can be managed with a concentric tube robot (CTR), a particular type of continuum robot. First, new anatomical data are elaborated, in particular for the olfactory cleft, that remains hardly characterized. 3D reconstructions are conducted on the database of 20 subjects, using CT scan images. Measurements are performed to describe the anatomy, including metrics with inter-subject variability. Then, the existence of collision-free passageways for CTR is shown using the 3D reconstructions. Among the 20 subjects, 19 can be inspected using only 3 different robot geometries. This constitutes an essential step towards a robotic device to inspect subjects for clinical purposes.

The Nasal Cavity of the Rat and Mouse-Source of Mesenchymal Stem Cells for Treatment of Peripheral Nerve Injury.

The nasal cavity performs several crucial functions in mammals, including rodents, being involved in respiration, behavior, reproduction, and olfaction. Its anatomical structure is complex and divided into several regions, including the olfactory recess where the olfactory mucosa (OM) is located and where the capture and interaction with the environmental odorants occurs. Among the cells of this region are the OM mesenchymal stem cells (MSCs), whose location raises the possibility that these cells could be involved in the peculiar ability of the olfactory nerve to regenerate continuously throughout life, although this relationship has not yet been confirmed. These cells, like all MSCs, present functional characteristics that make them candidates in new therapies associated with regenerative medicine, namely to promote the regeneration of the peripheral nerve after injury. The availability of stem cells to be therapeutically applied essentially depends on their collection in the tissue of origin. In the case of mice and rat's OM-MSCs, knowledge about the anatomy and histology of their nasal cavity is essential in establishing effective collection protocols. The present article describes the morphological characteristics of rodent's OM and establishes an alternative protocol for access to the olfactory recess and collection of the OM. Anat Rec, 301:1678-1689, 2018. © 2018 Wiley Periodicals, Inc.

Preparation of Human Olfactory Ensheathing Cells for the Therapy of Spinal Cord Injuries.

We developed an optimal protocol for preparing and culturing of olfactory ensheathing cells from human olfactory mucosa. Using this protocol, we obtained a culture enriched with human olfactory ensheathing cells. Immunofluorescence analysis by simultaneous expression of GFAP and p75NTR markers showed that the content of ensheathing cells was maximum in passage 3 and 4 cultures (94 and 89.5%, respectively). The developed protocol can be recommended for obtaining autologous preparations of human ensheathing cells for cell therapy of spinal cord injuries.

Management of long-lasting phantosmia: a systematic review.

BACKGROUND: Interest in the pathophysiology and management of phantom smells has increased rapidly over the last decade. A PubMed search for the term "phantosmia" demonstrated a near-doubling of articles published on phantosmia within the past 7 years. We aimed to systematically review the literature on the management of phantosmia. METHODS: The PubMed, EMBASE, and Cochrane databases were searched for articles published since January 1990, using terms combined with pertinent Boolean search operators. We included articles evaluating management of phantosmia written in the English language, with original data and a minimum of 6 months of follow-up, on at least 2 patients and with well-defined and measurable outcomes. RESULTS: A total of 2151 unique titles were returned upon the initial search. Of these, 146 abstracts were examined, yielding 7 articles meeting the inclusion criteria. All articles were predominantly level 4 evidence. One prospective level 3 study was included. The studies included a total of 96 patients, with follow-up ranging from 6 months to 11 years. Endpoints were primarily based on subjective patient responses. Management options included observation and medical and surgical therapy. Olfactory mucosa excision was the only surgical intervention studied, with short-term symptomatic improvement in 10 of 11 patients. Forty-one patients were treated medically, which included antipsychotic, antimigraine, and antiseizure medications, transcranial stimulation, and topical cocaine application. CONCLUSION: Despite increasing interest in the treatment of phantosmia and reports of successful therapies, there remains a paucity of data and lack of consensus regarding optimal management of this difficult condition.

Olfactory Epithelial Hamartoma: A New Subtype of Sinonasal Hamartoma.

Sinonasal epithelial hamartomas occurring in adults are classified as seromucinous hamartoma (SMH) or respiratory epithelial adenomatoid hamartoma (REAH). We describe herein a novel subtype of adult sinonasal hamartoma that contains olfactory epithelium, a histologic feature not previously reported in the literature. Our pathology department database was retrospectively searched for sinonasal hamartomas containing areas of olfactory epithelium. Six relevant cases (3 male and 3 female patients; age, 30 to 77 y) were retrieved, and available pathology slides and clinical and imaging data from patient charts were reviewed. Five of the lesions were unilateral solitary, polypoid, pedunculated masses, 38 to 80 mm in length, lodged in the nasal olfactory cleft. The sixth lesion was associated with bilateral nasal polyposis, and its precise localization was not known. All patients were treated by transnasal endoscopic surgery. None of the 3 patients who had received adequate follow-up evaluation exhibited recurrence. Histologically, all lesions resembled SMH or REAH, with areas of olfactory epithelium comprising olfactory receptors and sustentacular and basal cells. Olfactory epithelium was observed at the lesion surface or in invaginated gland-like structures, and it contained focal aggregates of filamentous cell processes. Some olfactory receptor cells or cell processes were also present in the seromucinous gland component of lesions. Olfactory receptor cells expressed CD56 (neural cell adhesion molecule), and the filamentous aggregates contained CD56, neurofilaments, and synaptophysin. Aside from SMH and REAH, we have described a third subtype of adult sinonasal hamartoma-olfactory epithelial hamartoma-which shares the benign character of the other 2.

Dissecting LSD1-Dependent Neuronal Maturation in the Olfactory Epithelium.

Neurons in the olfactory epithelium (OE) each express a single dominant olfactory receptor (OR) allele from among roughly 1,000 different OR genes. While monogenic and monoallelic OR expression has been appreciated for over two decades, regulators of this process are still being described; most recently, epigenetic modifiers have been of high interest as silent OR genes are decorated with transcriptionally repressive trimethylated histone 3 lysine 9 (H3K9me3) whereas active OR genes are decorated with transcriptionally activating trimethylated histone 3 lysine 4 (H3K4me3). The lysine specific demethylase 1 (LSD1) demethylates at both of these lysine residues and has been shown to disrupt neuronal maturation and OR expression in the developing embryonic OE. Despite the growing literature on LSD1 expression in the OE, a complete characterization of the timing of LSD1 expression relative to neuronal maturation and of the function of LSD1 in the adult OE have yet to be reported. To fill this gap, the present study determined that LSD1 (1) is expressed in early dividing cells before OR expression and neuronal maturation and decreases at the time of OR stabilization; (2) colocalizes with the repressor CoREST (also known as RCOR1) and histone deacetylase 2 in these early dividing cells; and (3) is required for neuronal maturation during a distinct time window between activating reserve stem cells (horizontal basal cells) and Neurogenin1 (+) immediate neuronal precursors. Thus, this study clarifies the role of LSD1 in olfactory neuronal maturation.

Periodic olfactory assessment in patients undergoing skull base surgery with preservation of the olfactory strip.

OBJECTIVES/HYPOTHESIS: Others have reported olfactory disturbances following endoscopic approaches to the skull base. However, there is a lack of consensus on the extent and duration of dysfunction. This study aimed to compare our results with previously published work and to validate the olfactory strip-sparing approach. STUDY DESIGN: Prospective study to assess olfaction in 50 patients scheduled to undergo resection of skull base tumors via extended endoscopic approaches. METHODS: Patients were divided into two groups. Group I had a nasoseptal flap (NSF), and group II included patients in whom rescue flaps were performed bilaterally. Olfactory outcomes were assessed using repeated University of Pennsylvania Smell Identification Test at baseline, 6 weeks, 3 months, and 6 months following surgery. RESULTS: Ultimately, 42 patients (seven group I and 35 group II) were available for assessment. Scores for group I were lower than at baseline at 6 weeks postoperatively (30.71 ± 5.5 vs. 24.5 ± 5.4; P = .05). However, by the third postoperative month the scores had improved to a level that was not significantly different from baseline (29.0 ± 3.7; P = .5). At 6 months, the score was 30.0 ± 3.9. Patients in group II showed no difference between their baseline and 6-week scores (31.5 ± 5.3 vs. 29.7 ± 5.9; P = .16). Six months postoperatively, the score was significantly higher (33.78 ± 3.6; P = .04). CONCLUSIONS: Expanded endoscopic approaches to skull base tumors involving reconstruction with an NSF are associated with a short-term negative impact on olfaction. Olfaction does not seem to be affected by the surgical resection of pituitary adenomas associated with rescue flaps. Identification of the olfactory epithelium and meticulous harvesting of the NSF are critical to preserve olfaction. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:1970-1975, 2017.

Safety of human olfactory mucosal biopsy for the purpose of olfactory ensheathing cell harvest and nerve repair: a prospective controlled study in patients undergoing endoscopic sinus surgery.

BACKGROUND: Nasal olfactory mucosa is an accessible source of olfactory ensheathing cells for spinal cord regeneration. However, safety of the biopsy technique and the effects on sense of smell and nasal function have not been robustly assessed in the form of a prospective controlled study. METHODOLOGY: National Health Service ethical approval was granted for this study of 131 patients. The primary outcome measure was olfactory function and the secondary outcomes included postoperative complication rates as well as the SNOT 22, NOSE scale scores and surgeon reported (Lund-Kennedy score) nasal function outcomes. RESULTS: 65 patients underwent functional endoscopic sinus surgery (FESS) and superior turbinate biopsy, and 66 patients underwent FESS only as the control group. There was no significant difference in complication rates between the two groups. All Olfactory function outcomes were unaffected following olfactory biopsy. We demonstrated that the patients quality of life and nasal patency as well as surgeon reported outcome measurements remain unaffected following olfactory harvesting. CONCLUSIONS: We have uniquely provided level 2a evidence for the safety of endoscopic biopsy of olfactory mucosa, which does not affect nasal function or the sense of smell compared to standard FESS without biopsy.

Obtaining the olfactory bulb as a source of olfactory ensheathing cells with the use of minimally invasive neuroendoscopy-assisted supraorbital keyhole approach--cadaveric feasibility study.

BACKGROUND: Obtaining the human olfactory bulb (OB) for treatment of spinal cord injuries with olfactory ensheathing cells (OECs) requires the elaboration of a surgical approach that could meet the criteria of safety and minimal invasiveness. The aim of the study was to evaluate the suitability of the keyhole supraorbital craniotomy (SOC) with an eyebrow incision for obtaining OB for therapeutic purposes. METHODS: Seventeen SOCs were performed on nine fresh adult cadavers. The procedure of obtaining OB was conducted by neuroendoscope-assisted microsurgical dissection. Technical features related to the procedure were measured and adverse events were noted. The virtual three-dimensional planning was applied in six cases to verify the authorial A-C scale published previously. RESULTS: The intact OB was obtained in 10 (59%) cases and a minor injury was discovered in another 5 (29%) cases. In 2 (12%) specimens OB was severely damaged which was correlated with the minor neural tissue injury (Fi(2) = 0.44). While no case of an evident vascular injury was noted, there were 3 (18%) incidents of unintended frontal sinus opening positively correlated with the craniotomy width (Fi(2) = 0.44). The unfavorable three-dimensional (3D) configuration of the olfactory groove area was revealed in 66% of cases and highly correlated with OB injury (Fi(2) = 1.0) but not damage. CONCLUSIONS: The SOC via an eyebrow incision may be safely and effectively applied to obtain the OB as a source of OECs in roughly 90% of cases. Virtual 3D planning is useful in preoperative qualification of potential donors.

Abordaje subfrontal para el tratamiento de un estesioneuroblastoma / Sub-frontal approach in the treatment of esthesioneuroblastoma

El estesioneuroblastoma es un tumor maligno de la mucosa olfatoria localizado en el tracto nasosinusal con un manejo controvertido debido a su baja incidencia y a su origen desconocido. La resección craneofacial, empleando un abordaje subfrontal, es uno de los abordajes de elección para el tratamiento de esta compleja entidad. Describimos un caso tratado en nuestra institución que fue resuelto favorablemente con este procedimiento, así como una revisión exhaustiva de la bibliografía con respecto a este tipo de tumor y a las ventajas de este abordaje (AU)

Esthesioneuroblastoma is a rare malignant tumor of the olfactory mucosa located in the sinonasal tract with a controversial management due to its low incidence and unknown origin. Craniofacial resection using a subfrontal approach is one of the techniques of choice for treating this complex entity. We describe a case treated in our institution that responded favorably to this procedure, as well as a thorough review of the literature regarding this type of tumor and the advantages of the approach (AU)

Long-term outcome of olfactory ensheathing cell transplantation in six patients with chronic complete spinal cord injury.

The aim of the study was to analyze the clinical efficacy and safety of olfactory ensheathing cell (OEC) transplantation for treating patients with chronic, complete spinal cord injury (SCI). Six patients with six chronic complete spinal cord injuries were recruited and treated with autologous OEC transplantation and followed for 24 months. The scores from before and after transplantation were analyzed. This was a self-control experiment. There was significant amelioration in the scores of the standard neurological classification of spinal cord injury made by the America Spinal Cord Injury Association (ASIA) and the International Association of Neurorestoratology-Spinal Cord Injury Functional Rating Scale (IANR-SCIFRS) following OEC transplantation with 24 months of follow-up. No clinical complications were observed. OEC transplantation would appear to be clinically safe and may promote the neurofunctional recovery of SCI based on data from six patients. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.

Evaluación del olfato en pacientes con patología tumoral en la región selar, intervenidos mediante abordaje endoscópico transesfenoidal transnasal / Assessment of smell in patients with tumor pathology in the sellar region, operated by transnasal transsphenoidal endoscopic approach

Introducción: Para acceder a la región selar, podemos utilizar las técnicas transcraneal, transeptal, o transnasal endoscópica, pudiendo provocar diferentes grados de hiposmia. Se ha descrito menor morbilidad al utilizar la técnica endoscópica, pero faltan estudios dirigidos a los resultados olfatorios. Objetivo: Determinar la presencia de deterioro olfatorio en los pacientes sometidos a un abordaje transnasal endoscópico. Material y método: Se reclutaron 12 pacientes con tumores en la región selar durante 8 meses. Se les realizó un test de olfato preoperatorio, fueron intervenidos mediante abordaje transnasal endoscópico y controlados al mes posoperatorio. Resultados: Se logró seguimiento a 10 pacientes. Seis (60%) presentaron un test de olfato preoperatorio normal. Al mes posoperatorio, se constató mejoría olfatoria en 1 (10%) paciente, 8 (80%) se mantuvieron en la misma categoría y 1 (10%) presentó deterioro olfatorio. En suma, 9 de 10 pacientes (90%) mantienen o mejoran su olfato al mes posoperatorio. Conclusión: Nuestros resultados sugieren que el abordaje transnasal endoscópico utilizado en este estudio no produce deterioro olfatorio. Dado que además es una técnica de abordaje efectiva y relativamente segura, consideramos que constituye una alternativa factible para utilizar en pacientes con patología tumoral en la región selar.

Introduction: To access the sellar region we can use the transcranial, transeptal, or transnasal endoscopic approaches, which may cause different degrees of hyposmia. It has described less morbidity to use the endocopic technique, however, there are few studies directed at olfactory outcomes. Aim: To determine the presence of olfactory impairment secondary to endoscopic transnasal approach. Material and method: 12 patients with tumors in the sellar region were enrolled during 8 months. They were underwent a smell test preoperatively, operated by endoscopic transnasal approach, and controlled with postoperative retesting, after one month. Results: Follow-up was achieved to 10 patients. 6 (60%) presented a normal preoperative smell test. Within one postoperative month, olfactory improvement was found in 1 (10%) patient, 8 (80%) remained in the same category and 1 (10%) had olfactory impairment. In all, 9 out of 10 patients (90%) maintain or improve their sense of smell after surgery. Conclusions: Our results suggest that the transnasal endoscopic approach used in this study, doesn't produce olfactory impairment. Given that is also an effective and relatively safe approach, we believe that is a feasible alternative for use in patients with tumor pathology in the sellar region.

Nasal polyps do not contain olfactory structures.

BACKGROUND: Nasal polyposis can lead to olfactory dysfunction, either due to physical obstruction of the olfactory cleft or physiological disruption of the olfactory neuroepithelium. Where medical therapy has failed to relieve symptoms of nasal polyposis, surgical excision can be considered. However, removal of polyps medial to the middle turbinate is controversial: some believe this will relieve physical obstruction to odourants, others state that removal here risks excising olfactory neuroepithelium. METHODS: We stained 25 nasal polypectomy samples from the area medial to the middle turbinate with olfactory marker protein. RESULTS: We confirmed that our staining method worked on normal olfactory tissue. However, no positive staining of nasal polyps was demonstrated. CONCLUSION: We conclude that nasal polyps medial to the middle turbinate do not contain olfactory neurons, and surgical excision is not contraindicated.

The human olfactory mucosa.

Studies of the tissues of the human olfactory mucosa have been performed to investigate olfactory dysfunction and, more recently, olfactory mucosa has attracted a novel interest of investigators because it can be used as an early marker of neurodegenerative conditions of the brain and as a source of multipotent neural stem cells, with applications in regenerative medicine. The olfactory mucosa is readily available to the otolaryngologist, but the harvesting of this tissue must be safe, effective, and reliable, obtaining as little tissue as necessary, while avoiding unnecessary harm to the remaining olfactory tissue and function. The purpose of this review is to summarize the results of the most important studies and knowledge with regard to the human olfactory mucosa and its applications, emphasizing the issue of the distribution of the olfactory mucosa in the nasal cavities.

The olfactory bulb and olfactory mucosa obtained from human cadaver donors as a source of olfactory ensheathing cells.

During the last decade, olfactory ensheathing cells (OECs) have been successfully applied in multiple experimental approaches aimed to repair damaged mammalian spinal cord. Some of these experiments have consequently been translated into clinical trials. Finding a reliable source of human OECs that is easily accessible and can ensure a sufficient number of cells is a major prerequisite for conducting studies on OEC-mediated spinal cord regeneration. Here, we present a procedure for obtaining olfactory bulbs (OBs) and olfactory mucosa (OM) simultaneously from adult cadaver heart-beating donors for OEC isolation and analyze some of the factors that may condition successful OEC culture. We show that the results of OEC culture from OBs (10 cases) correlated significantly with warm ischemia time (WIT) as well as the initial viability of the isolated cells. Efficient OEC culture was possible when the WIT for the OB was up to 20 min. Brain damage, assessed by determination of S100B serum level, was not related to the success of OEC culture from the OB. Cadaver OM (7 cases) was shown to be a more reliable source of human OECs than the OB. In most of the examined cases the efficacy of culturing OECs from cadaver OM obtained even 180 min after cardiac arrest was comparable to that of living patients. The method of obtaining OBs and OM from cadavers enables the use of an alternative source of primary adult human OECs for further preclinical and clinical studies on their neurotrophic properties.

Resection of the inferior superior turbinate: does it affect olfactory ability or contain olfactory neuronal tissue?

BACKGROUND: One approach to the sphenoid sinus involves resection of the inferior portion of the superior turbinate. There is general agreement from anatomic investigations that this area contains olfactory mucosa. This study will determine if olfactory tissue can be found in the superior turbinate mucosa of patients with chronic sphenoiditis and what effect its removal has on a patient's olfactory ability. METHODS: The inferior one-third of the superior turbinate removed during endoscopic sphenoidotomy was stained with olfactory marker protein antibody, a marker for mature olfactory tissue. The specimens were graded for content of olfactory neuronal elements. All patients underwent uninasal 12-item smell identification testing before surgery and at least 3 weeks after surgery. RESULTS: Fifty-five superior turbinate samples were taken from 31 patients. Nine (16%) of 55 samples contained olfactory neuronal elements that stained with olfactory marker protein. When comparing the pre- and postoperative smell test results, 52% of the nostrils had no more than a one-item change, 35% of the nostrils had a more than one-item improvement, and only 12% had more than a one-item loss. None of the nostrils with a loss of olfactory ability after the surgery showed olfactory neuronal elements in their superior turbinate specimens. CONCLUSION: There is olfactory mucosa in approximately one-sixth of the superior turbinate specimens removed during the endoscopic transethmoidal sphenoidotomy procedure. Although 12% of the patients had a loss of olfactory ability in this study, none of the loss could be attributed to excision of olfactory tissue.