Olfactory Filaments Research Articles

Microsurgical anatomy of the olfactory filaments in the nasal mucosa.

The aim of this study was to examine the distribution of olfactory filaments (OFs) in the nasal mucosa to facilitate preservation of olfactory function in endonasal approaches and preparation of a nasoseptal flap. One formalin-fixed and 9 fresh cadaveric silicone-injected specimens with 20 total sides were studied to measure the distance of the OFs to the anatomical landmarks and compare the OF presence in the nasal septum mucosa (NSM) and ethmoidal mucosa (EM). The mean distance from the first to the last OF was 19.37 ± 2.16 mm in the NSM and 23.44 ± 5.42 mm in the EM. The NSM had a mean of 7.55 ± 1.31 OFs and the EM had 14.3 ± 1.78. Average OF lengths were measured at 6.44 ± 1.48 (range 3.75-12.40) mm in the NSM and 8.05 ± 1.76 (range 4.14-13.20) mm in the EM. The mean values of the EM measurements were compared with those of the NSM; the number of OFs, the distance between the first and last OF, the average OF length, and the number of OFs between anterior and posterior ethmoidal arteries in the NSM were significantly less (p < 0.05) than those in the EM. The distance between the first OF to the nasal bone on the NSM was greater than on the EM. Compared with the EM, the OFs are significantly fewer in number and smaller in size in the NSM. The uppermost edge of the nasoseptal flap incision in the NSM might be safer to start below 12 mm from the cribriform plate for OF protection.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Approach to the Anterior Cranial Fossa.

Introduction The development of endoscopic techniques has made endoscopic endonasal approaches (EEAs) to the anterior cranial fossa (ACF) increasingly popular. Still, the steps and nuances involved in the approach may be difficult to understand for trainees. Thus, we aim to didactically describe the EEAs to the ACF in an anatomically based, step-by-step manner with supplementary clinical cases. Methods Six cadaveric head specimens were dissected. Endoscopic endonasal Draf I, IIA, IIB, and III frontal sinusotomies, endoscopic endonasal superior ethmoidectomy, and endoscopic endonasal transcribriform and transplanum approaches were modularly performed. The specimens were photodocumented with endoscopic techniques. Results Draf I frontal sinusotomy started with the complete removal of the anteromedial portion of the agger nasi cell, exposing the medial orbital wall, cranial base, and anterior cribriform plate. Draf II frontal sinusotomy proceeded with the removal of the floor of the frontal sinus between the lamina papyracea and the middle turbinate (IIa), and the nasal septum (IIb) until the first olfactory filaments were exposed. Draf III proceeded by creating a superior septal window just below the floor of the frontal sinus. The bone of the ACF bounded by the limbus sphenoidale posteriorly, frontal sinus anteriorly, and the medial orbital walls bilaterally was removed; the cribriform plate was removed; and the crista galli was dissected free from the dural leaflets of the falx cerebri and removed. Conclusion We provide a step-by-step dissection describing basic surgical steps and anatomy of the EEAs to the ACF to facilitate the learning process for skull base surgery trainees.

Морфологія нюхового аналізатора людини. Лекція

The sense of smell provides people with valuable information about the biochemical environment and their own body. Olfactory disorders occur in pathologies of the nasal cavity, liver cirrhosis, psychological and endocrine diseases. Smell affects various psychological aspects of people's lives, forming positive and negative emotional memories associated with smells. With the dysfunction of the olfactory analyzer, a person will not do the analysis whether the food is good, will not be able to feel the presence of poisonous gases in the air, bad breath. This puts a person in an awkward position and increases the risk of social isolation. The purpose of the study was to highlight the components of the normal structure and functioning of the human olfactory analyzer. Identification of odors in the environment and from one's own body is provided by the olfactory analyzer. Primary odors as camphor, floral, fruity, spicy, tarry, burnt and putrid in different quantities form secondary odors. Aromas are composed of volatile molecules called odorants. The smallest amount of odorant that causes an odor sensation is called the odor threshold. In people with coronavirus disease the sense of smell temporarily disappears (anosmia); it is reduced (hyposmia) in liver cirrhosis and rhinitis, and in Alzheimer's disease and schizophrenia besides hyposmia there is olfactory hallucination (phantosmia). Olfactory dysfunction adversely affects children's cognitive abilities. Fragrances change emotions and behavior. Aromas are used to regulate the physical and psychological state of the patient. Volatile molecules of fragrances penetrate through the layer of mucus that covers the olfactory epithelium located in the olfactory region of the nasal mucosa. The olfactory epithelium consists of olfactory, supportive and basal epitheliocytes, as well as secretory cells of the olfactory glands. Olfactory cells are modified nerve cells that have a body, an axon, and a dendrite, which ends with a receptor in the form of olfactory cilia. Volatile molecules interact with the olfactory cilia and then with the receptor protein, which is located on the olfactory cell bodies. In humans, olfactory cells have 350 receptor proteins. One type of receptor can register molecules of several different odorants. Molecules of the same odorant can activate several different receptors simultaneously. The nerve impulse from the olfactory cells (bodies of I neurons) reaches the nerve cells (bodies of II neurons) of the olfactory bulbs via their central outgrowths (olfactory filaments). Axons of nerve cells of olfactory bulbs continue to bodies of III neurons, which are located in subcortical centers of the brain (almond-shaped body, nuclei of the transparent septum). In human, to analyze a particular odor, axons from bodies of III neurons continue to cortex, namely to the area of the uncus of the parahippocampal gyrus

Management and rehabilitation of patients with persistent olfactory disorders (hypo- and anosmia) (literature review)

We present a review of the literature and our own data on the management and rehabilitation of impairment or persis‑tent loss of the olfactory function – hypo‑ and anosmia. Approaches for restoring impaired olfactory function can be divided into olfactory training, pharmacological and physiotherapy. Smell training is carried out according to a number of protocols that differ mainly in the used arsenal of smells, as well as in the frequency of their presentation. Pharma‑cologically, it is proposed to use steroids used both topically (intranasally) and systemically; there is no common view on the effectiveness of this approach. Physiotherapy involve electrical stimulation of the olfactory filaments in the area of their exit into the nasal cavity (lateral masses of the ethmoid bone). In our opinion the most rational approach is the use of training methods using different smells.

Endoscopic Study of the Distribution of Olfactory Filaments: A Cadaveric Study.

Provide a detailed anatomical description of the olfactory filaments (OF) and their distribution in the nasal cavity through endoscopic endonasal dissection. Four cadaveric specimens (8 sides) were used in this study. Nasoseptal (NSM), middle (MTM) and superior turbinate (STM) mucosa dissection was performed to identify the OF and follow them superiorly to the cribriform plate (CP). Measurements of the OF were taken on the NSM, MTM, STM under direct endoscopic visualization. A Student's T-Test was performed to compare means. The NSM contained a mean of 11 OF, distributed over surface area (SA) of 173 ± 31 mm2 with the highest density of OF being found at the posterior NSM. The MTM contained a mean 6 OF, covering a mean SA of 77 mm2, with the first OF found 5 mm from the anterior border of the MTM, on average. The STM had a mean 9 OF, with the OF covering a mean SA of 96 mm2. Overall mean OF length was 6 mm. The STM OF were significantly greater in number, with a greater distance from the first OF to last OF (p < 0.05) than the MTM OF. The STM and MTM combined were found to have a greater density of OF than the NSM. The STM contains a significantly greater number of OF covering a greater area than the MTM OF. Preservation of the STM and MTM in skull base defect repair, and in routine sinus surgery, can be as beneficial for olfactory function as preservation of the NSM; particularly in CP defect repair. Moreover, our findings indicate that nasoseptal flap harvest performed at least 6 mm from the skull base preserves OF in the NSM. To our knowledge, this is the first anatomical study of the OF through direct endoscopic observation and measurements.

Endonasal anatomy of the olfactory neural network: Surgical implications.

Define the anatomic distribution of the olfactory filaments within specific mucosal regions of the nasal cavity. Cadaveric study. Seventeen cadaveric specimens (34 sides) were dissected to study the anatomical distribution and density of olfactory fila within different regions of the nasal cavity. Olfactory fila were dissected retrogradely to their point of entry into the anterior cranial fossa through the cribriform plate. Anatomic relationships among various components of the olfactory system and their corresponding arterial supply were determined subjectively. The highest density of olfactory fila was found at the mucosa of the ethmoid roof and superior turbinates. Olfactory fila were found at regions not previously considered to be part of the olfactory system: lateral wall of the nose, ethmoidal bullae, and between the os sphenoidale and arc of the posterior choana. Furthermore, at the septum, 20% of the olfactory fila crossed contralaterally before exiting the nose. The anterior ethmoidal arteries were the primary blood supply to the olfactory epithelium. This study suggests that olfactory filaments extend beyond previously established boundaries. These findings may have clinical implications regarding oncologic resections and could serve as the foundation for the development of techniques that better preserve olfactory function. NA Laryngoscope, 2473-2477, 2018.

Morphological evaluation using MRI of the olfactory filaments (fila) in a post-traumatic olfactory rat model.

ObjectiveTo investigate whether magnetic resonance imaging (MRI) can be used to directly assess olfactory bulb (OB) lesions and quantify the associated morphological changes of olfactory filaments (OF), also known as fila, in an in vivo OB-lesion rat model of the brain.MethodsA surgical group (n = 5) of male Sprague–Dawley rats was subjected to the unilateral damage of the OB by a steel needle. The control group (n = 5) did not receive surgery. To assess olfactory system injury in vivo, T2-weighted MRI images were acquired in an oblique plane at a 30° angle from transverse plane one day after surgery. These brain regions were also assessed in the controls. The olfactory function was evaluated using the buried food pellet test (BFPT) 5 days before and after surgery.ResultsThe OF could be clearly observed on the MRI images from all animals. The left and right OF mean lengths (mm) were similar in the control group (0.81 ± 0.18 vs 0.89 ± 0.17, P > 0.05). In the surgical group, the OB was partially injured in all rats. These rats did not show differences in OF length between left- and right-side (0.83 ± 0.18 vs 0.93 ± 0.24, P > 0.05) at the time of measurement. The time (sec) required to find the food pellets in the BFPT was longer after than before the surgery (83.80 ± 34.37 vs 231.44 ± 53.23, P < 0.05).ConclusionsMicroMRI may be a feasible tool to evaluate the OF and OBs in rat models. The unilateral partial OB lesion model appears to be an effective post-traumatic olfactory dysfunction model.

MicroRNA-200 family members are weakly expressed in the neurosensory epithelia of the developing zebrafish (Danio rerio) inner ear.

MicroRNA-200 family members are expressed in the developing mouse inner ear and in zebrafish (Danio rerio) olfactory epithelia, taste buds, and neuromasts, and have also been shown to be associated with differentiation of olfactory and taste buds. However, the role of the miR-200 family in the inner ear of zebrafish had not been studied. We investigated the expression and function of the miR-200 family in the zebrafish inner ear via in situ hybridization and loss-of-function methods. Expression of the miR-200 family was weak and dispersed throughout the developing zebrafish inner ear. After knockdown of miR-200 family members in the developing inner ear, no significant differences in development were observed compared to the controls. Otic vesicles, otoliths, and semicircular canals appeared normal. Compared with less differentiated olfactory filaments in olfactory epithelia, the development of hair cells and statoacoustic ganglion neurons were normal. The kinocilia and stereocilia of hair cells, the innervation of hair cells, and the formation of ribbon synapses were also unaffected. Overall, we conclude that the miR-200 family has a negligible role in the development of zebrafish inner ear; the functions of the miR- 200 family may be organ-specific.

Evidence‐based management of a patient with anosmia

Evidence‐based management of a patient with anosmia

Subcranial management of 395 combined frontobasal-midface fractures.

In severe craniofacial injuries, the involvement of the skull base with concomitant major dural tears is significantly high. Our methods and treatment plan are controversial compared with the conventional procedure: primary urgent neurosurgical exploration and repair with deferral of maxillofacial reconstruction. To avoid the disadvantages of the transfrontal intracranial management of the skull base, we modified the transethmoidal approach so as to enable the subcranial exposure of all the anterior fossa planes, including the sellar-sphenoidal region. The advantages rendered by this method are the feasibility of an early one-stage craniofacial reconstruction and avoiding retraction of the frontal lobes and damage to the olfactory filaments. The reduction of pseudohypertelorism, the decompression of the optic nerve, and the meticulous reconstruction of the midface and skull base are performed in one session and are regarded as one entity. The results of the surgical management of 395 craniofacial injuries and the low rate of complications emphasize the advantages of the methods described in this article.

Advantages of an additional subcranial approach in the corrrection of craniofacial deformities

The subject of this paper are the advantages conferred by the subcranial and extracranial approach for the performance of fronto-orbital osteotomy and advancement. In contrast to the usual intracranial approach the resection of the ethmoidal and medial aspect of the orbital roof can be achieved by the subcranial and transethmoidal approach, thus avoiding any damage to the olfactory filaments. The resulting subcranial compartment, after radical resection of the ethmoidal cells, enables optimal visualization of the optic nerve and decompression from this access. Frontal lobe retraction is only necessary at the lateral fronto-temporal region in order to complete the lateral osteotomy. Thus the morbidity rate related to the intracranial procedure can be reduced. Further advantages are the watertight repair of the skull base with fascia lata and the drainage of the intercranial region avoiding the postoperative development of the Orbital Apex Syndrome.

Ultrastructural morphology of the olfactory pathway for cerebrospinal fluid drainage in the rabbit

Previous physiological studies indicate that the olfactory region serves as a major pathway for cerebrospinal fluid (CSF) drainage into the lymphatic system. The present study was undertaken to determine the ultrastructural characteristics of this egress route. New Zealand White rabbits received a single bolus injection of the tracer ferritin (MW 400,000) into both lateral ventricles in such a manner as not to raise the intraventricular pressure above the normal level. The animals were sacrificed via intracardiac perfusion of fixative between less than 12 minutes and 4 hours following injection. The cribriform region was removed en bloc, decalcified, sectioned coronally, and prepared for light and electron microscopic examination. The arachnoid, dura, and periosteum surrounding the fila olfactoria passing through the cribriform plate merge together and form the perineurium, which consists of multiple layers of loosely overlapping cells with widely separated junctions and few vesicles. The perineurium surrounding the olfactory filaments at the superficial submucosal level is only one cell thick. The subarachnoid space freely communicates with the perineural space surrounding each filament. No morphological barrier between the perineural space and the loose submucosal connective tissue was identified. Whether or not the perineurium was multi- or single-layered, ferritin was noted in abundance between the loosely overlapping perineural cells and in the submucosal connective tissue. The distribution of ferritin at 12 minutes was similar to that at 4 hours; however, the quantity of ferritin was increased at 4 hours. These results indicate that no significant barrier to CSF drainage is present at the rabbit cribriform region and that CSF reaches the submucosal region rapidly via open pathways.