Development of the Ethmoid Sinus and Extramural Migration: The Anatomical Basis of this Paranasal Sinus

["Radical" versus "functional" surgery of the paranasal sinuses-A contradiction?]

BACKGROUND AND OBJECTIVE

The terms "functional" and "radical" paranasal sinus surgery were often considered to be different operations which were mutually exclusive. This overview aims to look at the basics of these terms and surgical procedures and to work out the resulting surgical concepts for clinically relevant indications.

MATERIAL AND METHODS

Selective literature analysis using the data base PubMed, corresponding textbooks and resulting secondary literature regarding functional and radical or extended paranasal sinus surgery. Similarly, the current literature regarding clinically relevant indications for sinus surgery were analyzed.

RESULTS AND CONCLUSION

Modern pathophysiological knowledge, anatomically and pathophysiologically substantiated endoscopic surgical procedures and the usage of up to date technical possibilities have resulted in concepts which combine functional and so-called radical or extended surgery of the paranasal sinuses that complement each other and sometimes even overlap. The preoperative diagnosis and definition of underlying diseases are decisive and should be as precise as possible, as the extent and surgical details mainly depend on them: a sole creation of free drainage pathways, an additional creation of anatomical access for subsequent topical treatment or a complete (radical) removal of a pathological process.

Growth and microanatomy of the paranasal sinuses in two species of New World monkeys

Paranasal sinuses of living apes and humans grow with positive allometry, suggesting a novel mechanism for bone enlargement. Here, we examine the paranasal sinuses of the owl monkey (Aotus spp.) and a tamarin (Saguinus midas) across postnatal development. The prediction that paranasal sinuses grow disproportionately faster than the main nasal chamber is tested. We used diffusible iodine-based contrast-enhanced computed tomography and histology to study sinuses in eight Aotus and three tamarins ranging from newborn to adult ages. Sinuses were segmented at the mucosa-air cavity interface and measured in volume. All sinuses were lined by a ciliated respiratory epithelium, except for the ethmoid air cells in Aotus, which are lined in part by olfactory epithelium. An age comparison indicates that only the maxillary sinus and ethmoid air cells are present in newborns, and two additional sinuses (invading the orbitosphenoid and the frontal bone), do not appear until late infancy or later. Comparing newborns and adults, the main nasal airway is 10 times larger in the adult Aotus and ~ 6.5 times larger in adult Saguinus. In contrast, the maxillary sinus far exceeds this magnitude of difference: 24 times larger in the adult Aotus and 46 times larger in adult Saguinus. The frontal sinuses add significantly to total paranasal space volume in both species, but this growth is likely delayed until juvenile age. Results suggest ethmoid air cells expand the least. These results support our prediction that most paranasal sinuses have a distinctly higher growth rate compared to the main nasal chamber.

Comparative physiological anthropogeny: exploring molecular underpinnings of distinctly human phenotypes

Anthropogeny is a classic term encompassing transdisciplinary investigations of the origins of the human species. Comparative anthropogeny is a systematic comparison of humans and other living nonhuman hominids (so-called "great apes"), aiming to identify distinctly human features in health and disease, with the overall goal of explaining human origins. We begin with a historical perspective, briefly describing how the field progressed from the earliest evolutionary insights to the current emphasis on in-depth molecular and genomic investigations of "human-specific" biology and an increased appreciation for cultural impacts on human biology. While many such genetic differences between humans and other hominids have been revealed over the last two decades, this information remains insufficient to explain the most distinctive phenotypic traits distinguishing humans from other living hominids. Here we undertake a complementary approach of "comparative physiological anthropogeny," along the lines of the preclinical medical curriculum, i.e., beginning with anatomy and considering each physiological system and in each case considering genetic and molecular components that are relevant. What is ultimately needed is a systematic comparative approach at all levels from molecular to physiological to sociocultural, building networks of related information, drawing inferences, and generating testable hypotheses. The concluding section will touch on distinctive considerations in the study of human evolution, including the importance of gene-culture interactions.

Anatomic misconceptions regarding the agger nasi cell: A preliminary analysis utilizing endoscopic anatomic dissection and three-dimensional computed tomography

The agger nasi cell is a key anatomic landmark in endoscopic frontal sinus surgery. However, discord amongst authors regarding anatomic definition and prevalence raises questions of its suitability as a surgical landmark. The purpose of this investigation is to evaluate the agger nasi cell using radiographic imaging correlated with endoscopic anatomic dissection to consider the cell's role as a surgical landmark and to explore if three-dimensional computed tomography (3D-CT) technology can provide enhanced insight into this anatomy. CT scans of 11 cadaveric sinonasal complexes were studied using triplanar CT or 3D-CT scanning with stereoscopic 3D imaging. Endoscopic dissections were performed and video recorded. Attention was given to identify agger nasi pneumatization and its origin. Pneumatization of the agger nasi region was noted in 4/11 cases (36.4%) (in two cases the pneumatization arose from the frontal recess, in two from a true agger nasi cell). The agger nasi region appeared as solid unpneumatized bone in 4/11 cases (36.4%). In 3/11 cases (27.3%) limited pneumatization was noted, bordering on but not pneumatizing the agger nasi proper. It may be confusing for otolaryngologic surgeons in training to rely on the "agger nasi cell" as a surgical landmark due to misconceptions regarding the anatomy, prevalence and anatomic definitions. Using standard CT scans to teach anatomy may have shortcomings as compared to the gold standard of surgical dissection. However, new 3D-CT holds promise to more accurately reflect small microanatomic features and provide an improved road map of a patient's anatomy in surgery.

3D CT stereoscopic imaging: observations of the frontal and anterior ethmoid sinuses development from birth to early adulthood

Objective: Our objective is to provide observations demonstrated with 3Dimensional Computed x-ray Stereoscopic Imaging (3DCTSI) in the evaluation of the anterior ethmoid and frontal sinus development from birth to age 18. Methods: This is a retrospective evaluation of patient’s CT studies performed over a fifteen-year period, reported as normal studies, and included 53 patients (142 sides) from birth to age 18. Results: At birth, there are two spaces covered by folds, the uncinate and bulla lamellae. The spaces communicate with the Middle Meatus (MM) through the emerging ethmoid infundibulum (EI) and the retrobulbar recess space (RBRS). In the first month after birth, an expansile and breakdown developmental phase blend and continue throughout the growth into the teenage years. The 3D images reveal dark lamellar structures, on the surface of the medial lamina papyracea as well as bridging the broken spatial outlines. The dark lamellae represent the mucosal lamina propria, in unossified lamellae and are the origin of permanent spatial walls. From ages 4 to 18 years, initially, the frontal recess (FR) and later the MM penetrate into the cancellous frontal bone creating the frontal Sinus (FS), the frontal septum (FS), Inter-Frontal Sinus Septal Cell (IFSSC), as well as the Fronto-Ethmoidal and Frontal Bulla Spaces. Conclusion: 3DCTSI is the first intuitive imaging modality to reveal the microanatomical development of the anterior ethmoid and frontal sinus anatomy.

Anosmia following middle nasal concha resection: an anatomic and developmental review with clinical correlation

Losing the sense of smell can be associated with a significant decrease in quality of life. Fortunately, this occurs infrequently with modern paranasal sinus surgery that has stressed minimally invasive, tissue-sparing principles. However, over time, more extensive surgical applications have emerged that incorporate increased tissue removal. Post-operative period sequelae can occur, including anosmia. Understanding the potential implications of expanded tissue removal, such as middle nasal concha (turbinate) resection, is clinically important and is facilitated by an understanding of anatomy. Our understanding of anatomic nuances is enhanced through an appreciation of embryonic and fetal development. We herein review the developmental anatomy of the middle nasal concha of the ethmoid sinus and olfactory nerve area as it relates to middle nasal concha removal during endoscopic sinus surgery. We present images from our analysis of twelve embryonic and fetal specimens that highlight the important relationship between the middle nasal concha and olfactory nerves. We also review the clinical issues surrounding turbinate preservation versus resection and present a clinical correlation to underscore the uncommon but significant complication of anosmia following sinus surgery with middle nasal concha resection. We highlight knowledge gaps, discuss case selection and review surgical technique modifications for middle nasal concha surgery to reduce the chance of this complication in the future. This article is protected by copyright. All rights reserved.

Patterns of Pneumatization of the Posterior Nasal Roof

(1) Background: For good surgical performance, sound knowledge of anatomy is required. Although the ethmoid air cells and sphenoid sinuses are subject to a high degree of variation, their possible extensions above the nasal fossa at the posterior end of the cribriform plate of the ethmoid bone (CPEB) were seemingly overlooked. (2) Methods: We retrospectively studied 162 case files from 55 male and 107 female cases, with ages varying from 42 to 80, which were scanned using Cone Beam Computed Tomography. (3) Results: In 56.17% of cases, an unpneumatized CPEB (type I) was found. Nasal roof recesses of ethmoidal origin (type II) were found at the posterior end of the CPEB in 20.37% of cases. Different types of sphenoidal pneumatizations of the posterior end of the CPEB (type III) were found in 22.83% of the cases. Onodi cells projected nasal roof recesses (type IV) in only 10 cases. In all types, nasal roof recesses were found either above the CPEB or within/underneath it. Moreover, such nasal roof recesses were found to be either unilateral, extended contralaterally, or bilateral. (4) Conclusions: As such recesses of the posterior CPEB, previously overlooked, belong to the posterior rhinobase, they should be carefully documented preoperatively to avoid unwanted surgical damage to the olfactory bulb or CSF fistula.

N, Hosemann W. Supplements and refinements to current classifications and nomenclature of the fronto-ethmoidal transition region by systematic analysis with 3D CT microanatomy

Objective: The microanatomy of the fronto-ethmoidal transition region has been addressed in several classifications. CT stereoscopic imaging (3DCTSI) provides improved display and delineates three defined complex “spaces”, the Frontal Sinus/Frontal Recess Space, the Infundibular Space of the Ethmoid Uncinate Process, and the Ethmoid Bulla Space (FSRS, IS-EUP, EB), none of which were adequately described with the “cell” terminology. We present details on the 3D microanatomy, variability, and prevalence of these spaces. Methods: 3D stereoscopic imaging displays (3DCTSI) were created from 200 datasets. The images were analyzed and categorized by a radiologist (SJZ), and consultant otolaryngologists, focusing on 3D microanatomy of the fronto-ethmoidal transition, the frontal recess/frontal sinus, and drainage pathways, in comparison to established anatomical classification systems. Results: The anterior ethmoid is subdivided into seven groups with the following core properties and prevalence: 1. The horizontal roof of the IS-EUP is attached to the superior half of the frontal process of the maxilla (19%); 2. The IS-EUP extends into the frontal recess (6.5%); 3. The IS-EUP extends into the frontal recess and the frontal sinus (18.5%); 4. A bulla is seen in the medial frontal sinus (3%); 5. The ethmoid bulla and supra bullar space extend into the frontal sinus (7%); 6. Lamellae extend into the FSRS antero-superiorly (25%); 7. FSRS expansion expands below the upper half of the frontal process of the maxilla (FSRS) (21%). Conclusion: 3-D analysis of the detailed anatomy provides important new anatomic information with the increased focus on precision surgery in the region.

Anatomical Study of Ethmoidal Foramina and Optic Canal in Endoscopic Trans-Nasal Approach to Anterior Skull Base

BACKGROUND

Surgery to anterior skull base is challenging since complex structures are involved. Injury of olfactory fila and optic nerve may result in postoperative complications. In our study, the authors aim to use computer topographic image to provide a comprehensive anatomical information of anterior skull base and set up a new classification of optic canal (OC) in ethmoid sinus by the degree of bony defect, so as to help surgeons in endoscopic transnasal approach to anterior skull base.

METHOD

Computer topographic angiography images of 112 individuals were reviewed, the measurement was performed on coronal, sagittal, and axis planes after the multiplanar reformation. Nostril and mid-sagittal lines were used to locate the anterior, middle, and posterior part of ethmoidal foramina and orbital opening of OC. Further, the authors classified OC in ethmoidal sinus into 4 types by the degree of the bony defect.

RESULT

Distance between nostril to anterior, middle, and posterior part of ethmoidal foramina and OC are 6.23 ± 0.21, 6.62 ± 0.26, 7.29 ± 0.25, and 7.76 ± 0.41 mm, respectively. Angle between line from nostril to ethmoidal foramina and horizontal plane are 47.50° ± 1.03°, 41.67° ± 1.33°, 37.20° ± 1.34°, respectively. For the 4 types of OC, the percentage is 15.6%, 11.6%, 31.3%, and 41.5%, respectively.

CONCLUSIONS

Our findings provide anatomical information of ethmoidal foramina and OC during endoscopic transnasal approach to anterior skull base, on the basis of some fixed anatomical landmarks. So as to enhance the surgical safety of this procedure and aid in the choice of the appropriate endoscopic equipment for the procedure.

Ethnic variation in medial orbital wall anatomy and its implications for decompression surgery

Background

To describe the inter-ethnic variation in medial orbital wall anatomy between Chinese, Malay, Indian and Caucasian subjects.

Methods

Single-centre, retrospective, Computed Tomography (CT)-based observational study. 20 subjects of each ethnicity, were matched for gender and laterality. We excluded subjects younger than 16 years and those with orbital pathology. OsiriX version 8.5.1 (Pixmeo., Switzerland) and DICOM image viewing software CARESTREAM Vue PACS (Carestream Health Inc., USA) were used to measure the ethmoidal sinus length, width and volume, medial orbital wall and floor angle and the relative position of the posterior ethmoid sinus to the posterior maxillary wall. Statistical analyses were performed using Statistical Package for Social Sciences version 25.0 (IBM, USA).

Results

There were 12 males (60 %) in each group, with no significant difference in age (p = 0.334–0.994). The mean ethmoid sinus length in Chinese, Malay, Indian and Caucasian subjects, using the Chinese as reference, were 37.2, 36.9, 38.0 and 37.4mm, the mean width was 11.6, 10.5, 11.4 and 10.0mm (p = 0.020) and the mean ethmoid sinus volume were 3362, 3652, 3349 and 3898mm³ respectively. The mean medial orbital wall and floor angle was 135.0, 131.4, 131.0 and 136.8 degrees and the mean relative position of posterior ethmoid sinus to posterior maxillary wall were − 2.0, -0.2, -1.5 and 1.6mm (p = 0.003) respectively.

Conclusions

No inter-ethnic variation was found in decompressible ethmoid sinus volume. Caucasians had their posterior maxillary sinus wall anterior to their posterior ethmoidal walls unlike the Chinese, Malay and Indians. Awareness of ethnic variation is essential for safe orbital decompression.

The sphenoethmoidal sinus and the modified anatomy of the related structures

The anterior extent of the sphenoidal sinus in the posterior ethmoid was less investigated. Our purpose was to study whether, or not, the occurrence of a sphenoethmoidal sinus (SES) relates to a sagitally-shortened ethmoid. A retrospective cone-beam computed tomography (CBCT) was performed on 36 patient files. In six patients were found SES extended anteriorly above the posterior third of the middle turbinate (MT). Two of these patients had bilateral SES with ethmoidal chambers included in the lateral and superior nasal walls and draining in the sphenoethmoidal recesses. The correlation between the nasion-to-concha sphenoidalis distance and the presence of SES was statistically significant (less than 40 mm in SES cases and more than 40 mm in non-SES cases). We also found: (i) superior turbinates (STs) with ethmoidal and sphenoidal insertions on one side and ethmoidal and maxillary insertions on the opposite side (the maxillary insertion of ST modifies surgical landmarks and was not previously reported), (ii) MT perforation and (iii) pterygoid recess of the maxillary sinus located beneath the pterygopalatine ganglion fossa. The SES thus shortens sagitally the lateral nasal wall but does not modify its morphology. The MT perforation, ST maxillary insertion and the pterygoid recess are rare anatomic variants not reported previously in our knowledge.

Paranasal sinus development and implications for imaging

Because the paranasal sinuses continue to develop throughout childhood, radiologists encounter significant anatomical variation when confronted with pediatric imaging studies. Knowledge of the stages of sinus growth is vital to differentiate normal development from abnormally large, hypoplastic or malformed sinuses. Understanding how the paranasal sinuses develop and their expected appearance at different patient ages is important for accurate interpretation of diagnostic imaging. To that end, we provide a brief review of paranasal sinus anatomy and discuss the mechanisms by which each paranasal sinus develops, as well as the implications for imaging. We also provide a practical guide for assessing normal paranasal sinuses in children based on the relationship of the sinuses to anatomical landmarks at various stages of development in order to help pediatric radiologists provide accurate interpretation of diagnostic imaging.

Anatomy of the paranasal sinuses of the common marmoset (Callithrix jacchus Linnaeus, 1758) and radiographic positioning for diagnosis of these structures

BACKGROUND

Callithrix jacchus, it is a species highly targeted by wild animal traffickers and, when apprehended, they need veterinary care. For safe therapeutic procedures, knowledge of anatomy is essential, as well as for diagnostic by imaging, good radiographic positioning is essential.

METHODS

The anatomy of the paranasal sinuses and the radiographic projections was described using 10 carcasses of common marmosets. Radiographs were taken in two panoramic views of their head: profile and frontal-naso. For the anatomical study, paramedian and transverse macroscopic sections and microscopic transverse sections were performed.

RESULTS

On the radiographs, it was possible to identify the frontal recess and maxillary sinuses in profile and frontal-naso incidences. In the anatomical study, the frontal recess and maxillary, sphenoid and ethmoid paranasal sinuses were identified.

CONCLUSIONS

The ethmoidal sinus could be observed only microscopically and the sphenoidal sinus difficult to see on the radiography due to the overlapping adjoining structures.

The Relationship Between Nasal Septal Deviation and Paranasal Pneumatization

OBJECTIVE

To investigate the impact of the presence and the severity of the nasal septal deviation (NSD) on the paranasal pneumatization.

METHODS

Initially, the deviated and contralateral sides was compared to evaluate the impact of the presence of NSD on pneumatization. Then, NSD classification groups were categorized according to the severity of deviation degree; 1: mild (<9°), 2: moderate (9°-15°), and 3: severe (>15°). Pneumatization of all paranasal sinuses, osteomeatal complex (OMC), frontoethmoid recess (FER) and variant structures were compared according to the NSD classification groups separately both for the deviated and the contralateral sides.

RESULTS

Although there was no statistically significant difference in pneumatization of the paranasal sinuses between the deviated and contralateral sides, a significant difference was observed in OMC and FER diameters. In the deviated side, there was statistically significant difference in ethmoid sinus volume, in FER and OMC diameters between NSD classification groups. In the contralateral side, FER and OMC diameters were found to be significantly different between group 1 and group 2 and between group 1 and group 3, respectively (P = 0.04 and 0.06, respectively). Both the presence and severity of the NSD did not statistically significant influence the pneumatization of variant structures, air cells and vital structures.

CONCLUSION

The severity of NSD effects the ethmoid sinus volume. The relationship of FER and OMC with NSD is evident, however this may not always be in a proportional pattern. The paranasal pneumatization did not affect Keros type, bone integrity of carotid canal and optic canal.

The Whole Lateral Type of the Sphenoethmoidal Cell and Its Relevance to Endoscopic Sinus Surgery

BACKGROUND

The sphenoethmoidal cell and the sphenoid sinus (SS) show great similarity in endoscopy and imaging. Hence, it is important to accurately identify the sphenoethmoidal cell preoperatively to prevent injury of the nerve and artery during endoscopic surgery. The aim of the present study was to investigate a special type of sphenoethmoidal cell.

METHODS

A total of 365 inpatients whose paranasal sinus computed tomography (CT) was collected and reviewed from May 2018 to September 2019 were included. The anatomical imaging characteristics of the sphenoethmoidal cell were observed.

RESULTS

A special type of the sphenoethmoidal cell was found on 9 sides in 730 sides (1.3%), according to its extension to the SS. Unlike Onodi cell (49.6%) and Jinfeng cell (1.3%), this cell simultaneously extends toward the superolateral, lateral, and inferolateral regions of the SS and is simultaneously closely attached to the optic canal and the maxillary nerve. Presently, this cell is named as the whole lateral type of the sphenoethmoidal cell, and the SS is located at the medial or inferomedial of it.

CONCLUSIONS

When evaluating the paranasal sinus CT preoperatively, attention must be paid to the possibility of the whole lateral type of sphenoethmoidal cell appearing, not just Onodi cell, extending into the SS.

Adult and Pediatric Lateral Lamella Cribriform Plate Height: In Need for a Comparative Study

Surgery for sinuses has evolved with the advancement of instruments and modification in techniques. Endoscopes have expanded the surgical roles for lesions in the nose and para-nasal sinuses with reduced rate of complications and cosmetic side effects. Nevertheless sinus surgery in pediatrics patients has its own challenges. Pre-operative imaging is of paramount important especially when embarking on skull base procedures. The differences between adult and pediatric anatomy need to be further studied.

Posterior ethmoid cell expansion towards the inferolateral region of the sphenoid sinus: a computed tomography study

OBJECTIVE

The aim of this study was to investigate the anatomical imaging characteristics of posterior ethmoid cells (PEs) expanding towards the inferolateral region of the sphenoid sinus (SS).

METHODS

This study included a total of 278 inpatients (556 sides) whose paranasal sinus computed tomography (CT) scans were reviewed and collected from May 2018 to February 2019. The anatomical imaging characteristics of PEs expanding towards the inferolateral region of the SS were observed.

RESULTS

PEs expanding towards the inferolateral region of the SS formed an inferolateral spheno-ethmoid cell (ISEC). ISECs were observed on three sides (0.54%; 3/556) in three cases (1.08%; 3/278). All of the ISECs were present unilaterally on the right side of the SS. The ISECs originated from the most posterior ethmoid cell; they were first located at the medial aspect of the orbital apex, pneumatized continually backward to the inferomedial wall of the orbital apex, and then extended into the lateral region of the SS. The ISECs further extended laterally, inferiorly and posteriorly beyond the sphenoid body into the greater wing and/or pterygoid process.

CONCLUSION

An ISEC is a rare variation of ethmoid air cells. Preoperative recognition of ISECs is essential to achieve safe and effective endoscopic sinus surgery because of the important anatomical location.

Agger Nasi Cells Versus Lacrimal Cells and Uncinate Bullae in Cone-Beam Computed Tomography

The maxillary bone's frontal process, lacrimal bone, and ethmoidal labyrinth's uncinate process can each harbor pneumatizations, referred to as agger nasi cells (ANCs), lacrimal cells (LCs), and uncinate bullae (UBs), respectively. Different studies have failed to differentiate ANCs from LCs. We aimed at studying these 3 anatomic sites to establish the anatomical patterns that could be encountered. We performed a retrospective study on cone-beam computed tomography scans of 36 patients (72 sides); the anatomic identification was supported by bidimensional multiplanar reconstructions (MPRs) in all 3 planes and 3-dimensional volume renderings. We established 6 patterns of pneumatization as follows: (1) type I: single LCs (47%), (2) type II: distinctive adjacent LCs and ANCs (8%), (3) type III: LCs expanded as UBs (6%), (4) type IV: ANCs adjacent to LCs expanded with UBs (1%), (5) type V: ANCs expanded as LCs (27%), and (6) type VI: ANCs expanded as LCs and further expanded as UBs (11%). In a type I pattern case, we found a cell-in-cell aspect on sagittal MPRs, which was further demonstrated as being an anterolateral recess of the middle nasal meatus projected in front of an LC. Such an "agger nasi recess" of the middle meatus was not previously described. For an accurate anatomical diagnosis, computed tomography studies should use complementary MPRs in all anatomical planes, as well as 3-dimensional models, to avoid confusing ANCs with LCs and better document the drainage pathways.

Analysis of the development of human foetal nasal turbinates using CBCT imaging

PURPOSE

The morphological structure of the nasal cavity (NC) is important for endoscopic surgical treatment. The location of nasal turbinates, including the superior turbinate (ST), middle turbinate (MT) and inferior turbinate (IT), are well presented during the formation of the human NC in cone beam CT (CBCT) images. There is a complex relationship between the nasal sinuses, the maxillary sinus (MS), ethmoidal sinus and sphenoid sinus, during formation of the NC structure at the morphological level. There is a need to clearly define the relationships of these nasal elements at the ossification level, during development.

METHODS

We investigated the three-dimensional construction of human foetal NC elements, including ST, MT, IT and vomer, using CBCT images from 16 weeks gestation (E16) to E31 (25 foetuses) and compared it to histochemical observations (E25).

RESULTS

At the stage of ossification, the studied elements are elongated in the posterior region near the sphenoidal bone, showing that the locations of the ST, MT, and IT are important during formation of the NC. CBCT analysis revealed that the horizontal and vertical directions of nasal turbinates affect the formation of the human NC.

CONCLUSION

The location and elongated development of the MT is one of the most important elements for NC formation. The relationship between the nasal sinus and nasal turbine at the level of ossification may provide useful information in clinical treatment of children.

Vertical and sagittal combinations of concha bullosa media and paradoxical middle turbinate

Common anatomic variants of the middle nasal turbinate include its pneumatization (i.e. concha bullosa media) and its paradoxical curvature. We report here two cases of differently combined variations of the middle turbinate which were documented in cone beam computed tomography (CBCT). The first report presents the vertical combination of a double or septated lamellar concha bullosa with the paradoxical curvature of middle turbinate. This combined variant associated (coincidental findings): ipsilateral paradoxical superior turbinate and contralateral paradoxical middle turbinate, concha bullosa superior and concha bullosa suprema. In the second case was found the sagittal combination of successive anterior concha bullosa media and posterior paradoxical curvature of the middle turbinate. An ethmoidal sinolith was found embedded in lamella basalis. The contralateral superior turbinate was pneumatized. These rare findings demonstrate that sound knowledge of possible anatomical variations, supported by a complete use of the tools available for the CBCT documentation of cases, is able to enrich the picture of human anatomic variations, with a direct impact on clinical and surgical practice. The septa-containing lamellar concha bullosa and paradoxical middle concha combination is a variation that affects surgical practice.

Imaging and anatomical features of ethmomaxillary sinus and its differentiation from surrounding air cells

OBJECTIVE

The aim of this study was to investigate the imaging anatomical characteristics and clinical significance of the ethmomaxillary sinus (EMS).

METHODS

The study included a total of 280 ENT Outpatient Department patients with nasal symptoms whose paranasal sinus CT scans were analyzed from January 2012 to December 2016. The anatomical imaging characteristics of EMS were observed.

RESULTS

EMS was observed in 23 of 280 patients, with an incidence of 8.2%. Bilateral EMS appearance in 17 cases (73.9%) was significantly higher than that of unilateral EMS in 6 cases (26.1%) (P < 0.01). EMS occurs when there are anterior or anterior-inferior cells of the posterior ethmoidal sinus (PEs) extending toward the maxillary sinus (MS) and entering the MS through the maxillary hiatus rather than spreading from outside of the MS. EMS is surrounded by five walls, and the main position of EMS was invariably located in the posterior-superior corner of the MS and draining to the superior nasal meatus (SNM). EMS must be differentiated from SNM, sphenoid sinus, and retromaxillary pneumatization of PEs, because they may appear between the MS and the orbital floor.

CONCLUSION

EMS was not a rare variation that should be careful identification during endoscopic sinus surgery. Accurately confirming EMS is the key to completely opening and removing lesions in the MS and EMS.

The Terracol and Ardouin developmental model of frontal sinus drainage pathway and surrounding spaces: a radiologic validation

BACKGROUND

The complexity of the frontal sinus drainage pathway (FSDP) can be challenging even for expert surgeons. Several classifications have been proposed to simplify the understanding of FSDP, whose anatomical variability can be simplified based on the knowledge of its developmental mechanisms.

METHODS

Cone-beam computed tomography studies performed at the Unit of Radiology of the University of Brescia between March and November 2012 were retrospectively analyzed. FSDP was classified as medial or lateral to the vertical portion of the uncinate process and the following anatomical variants were studied: agger nasi cell, Kuhn's cells, suprabullar cell, supraorbital ethmoid cell, suprabullar frontal cell, and frontal septal cell. The developmental model of the FSDP proposed by Terracol and Ardouin was analyzed and expected associations between the position of the drainage pathway and anatomical variants were formulated. Statistical associations between anatomical variants and the position of FSDP were calculated and compared with expected associations to validate the developmental model.

RESULTS

The anatomical variants of FSDP statistically validated the developmental model of Terracol and Ardouin.

CONCLUSION

Knowledge of the possible developmental patterns of FSDP helps the surgeon in the understanding of the complexity of the frontoethmoidal region.

Chronic nasal dysfunction

Chronic nasal dysfunction is a clinical concept in the diagnostic and therapeutic management of sinonasal diseases, based on the evo-devo theory of formation of the nose according to which the nose is not a single organ but rather an association of three organs: olfactory nose, respiratory nose and paranasal sinuses. In chronic nasal dysfunction theory, etiological diagnosis takes account of the possible pathophysiological independence of nasal symptoms, in accordance with the different origins and physiology of the three organs constituting the nose. The diagnostic approach of the chronic nasal dysfunction concept breaks down the pathology so as to propose treatment(s) adapted to the diseased organ(s) and to the capacity for physiological resolution of dysfunction induced in one organ by pathology in a neighboring nasal organ. The ethmoid is not a sinus according to evo-devo, and therefore functional endoscopic endonasal surgery (FEES) cannot be restricted to functional endoscopic sinus surgery (FESS). Evo-devo theory and the chronic nasal dysfunction concept offer an alternative to the concept of chronic rhinosinusitis with or without polyps for the management of sinonasal diseases.

Frequency and volumetry of infraorbital ethmoid cells (Haller cells) on cone-beam computed tomograms (CBCT) of the mid-face

Objective: The aim of this study was to determine the frequency and morphology of Haller cells using a new radiological technique that allows examination of the facial skull.

Material and methods: In a single center retrospective cohort study the cone-beam computed tomography (CBCT) volume data of the maxillary sinus of 199 patients were analysed (398 paranasal sinuses). If Haller cells were found, their capacity was determined. If orthopantomograms (OPG) were taken in a narrow time frame around the CBCT investigation, the rate of correspondence of the radiological findings was determined. The correlation between frequency of Haller cells and age and gender was calculated.

Results: Out of 199 patients 47 showed at least one Haller cell (23.62%). The total number of Haller cells was 64. Correspondence was rare in the same case between the results from different examination procedures with respect to the target object.

Conclusions: Bony variants of paranasal sinuses can be analysed using CBCT as an alternative to computed tomography (CT), whereas OPG images do not reliably detect Haller cells.

Computed tomographic analysis of frontal recess cells in pediatric patients

OBJECTIVE

To describe the prevalence of frontoethmoid cells and superior uncinate process attachment in pediatric patients with sinonasal symptoms.

METHOD

Fifty high-resolution computed tomographies of the paranasal sinuses for pediatric patients were evaluated for the presence of frontoethmoid cells and uncinate process insertion. The computed tomographies were randomly collected for patients with sinonasal symptoms (age range, 4-15 years) at our clinic. The prevalence of these cells was compared against age group and type of uncinate process.

RESULTS

The prevalence of each structure was agger nasi cell (97%), type 1 frontal cell (39%), type 2 frontal cell (27%), type 3 frontal cell (11%), type 4 frontal cell (1%), supraorbital ethmoid cell (38%), suprabullar cell (57%), frontal bullar cell (9%), and interfrontal septal cell (16%). When excluding the agger nasi cell, 48 patients (96%) had at least one type of frontoethmoid cell and 43 (86%) had at least one frontal cell. The frequency of these cells did not significantly differ based on sex or uncinate process insertion, but it did with age. Lamina papyracea was the most common site of superior uncinate process attachment.

CONCLUSION

Our results indicated a high frequency of frontoethmoid cells in the pediatric age group. The prevalence of these variations changes during childhood development. As in adults, lamina papyracea is the most common site of superior uncinate process attachment. Recognition of these variations in the frontal recess can provide useful information for safe and efficient endoscopic dissection in the frontal recess region.

Structure of the lateral mass of the ethmoid by curved stacking of endoturbinal elements

CONTEXT

According to evo-devo theory, the embryonic development of the nasal organ mimics its phylontogenic formation: the lateral masses of the human ethmoid bone develop by curved "onion" stacking of the endoturbinals (the horizontal bone septa of the mammalian olfactory chamber) under the impact of facial and skull-base remodeling, rather than by pneumatization of cavities communicating via ostia.

OBJECTIVES

To assess the frequency of the onion structure on coronal CT.

MATERIAL AND METHODS

Three independent examiners performed a retrospective descriptive study of coronal CT scans taken ahead of septorhinoplasty between June 2010 and December 2012 in adult patients without history of sinonasal surgery.

RESULTS

Fifty patients were included. In the anterior right and left and posterior right ethmoid, an onion arrangement of the endoturbinals was systematically found on at least 1 view, and on 60% of views taking all ethmoid compartments together. Two endoturbinals were generally involved, but a rolling-up of 3 endoturbinals was also observed, significantly more frequently in the posterior compartments (P=0.004 on the right side, P=0.012 on the left).

CONCLUSION

The onion structure of the lateral masses of the ethmoid can be observed on coronal CT scans. This structure confirms evo-devo theory. The ethmoid thus appears fundamentally different from the paranasal sinuses, suggesting that the pathogenesis of nasal polyposis and ethmoidectomy techniques need to be reconsidered.

The olfactory fascia: an evo-devo concept of the fibrocartilaginous nose

PURPOSE

Evo-devo is the science that studies the link between evolution of species and embryological development. This concept helps to understand the complex anatomy of the human nose. The evo-devo theory suggests the persistence in the adult of an anatomical entity, the olfactory fascia, that unites the cartilages of the nose to the olfactory mucosa.

METHODS

We dissected two fresh specimens. After resecting the superficial tissues of the nose, dissection was focused on the disarticulation of the fibrocartilaginous noses from the facial and skull base skeleton.

RESULTS

Dissection shows two fibrocartilaginous sacs that were invaginated side-by-side in the midface and attached to the anterior skull base. These membranous sacs were separated in the midline by the perpendicular plate of the ethmoid. Their walls contained the alar cartilages and the lateral expansions of the septolateral cartilage, which we had to separate from the septal cartilage. The olfactory mucosa was located inside their cranial ends.

CONCLUSION

The olfactory fascia is a continuous membrane uniting the nasal cartilages to the olfactory mucosa. Its origin can be found in the invagination and differentiation processes of the olfactory placodes. The fibrous portions of the olfactory fascia may be described as ligaments that unit the different components of the olfactory fascia one to the other and the fibrocartilaginous nose to the facial and skull base skeleton. The basicranial ligaments, fixing the fibrocartilaginous nose to the skull base, represent key elements in the concept of septorhinoplasty by disarticulation.

Agger-bullar classification (ABC) of the frontal sinus drainage pathway: validation in a preclinical setting

BACKGROUND

The anatomy of structures surrounding the frontal sinus drainage pathway (FSDP) is extremely complex and challenging for endoscopic sinus surgeons. The anatomical nomenclature of this area reflects this complexity and lack of agreement regarding anatomical variants of this region is present in the literature. This work presents a new classification system of the air spaces surrounding the FSDP, called the agger-bullar classification (ABC), and compares it with the most widely used anatomical classification of the frontoethmoidal region, the modified Bent and Kuhn classification (MBKC).

METHODS

Fourteen human heads underwent cone beam computed tomography (CT) scan and subsequently endoscopic dissection. Anatomical data were collected by 2 radiologists in consensus, an expert surgeon, and a novice surgeon. The radiologists filled the anatomical report after examining the CT scan, and the expert surgeon had both CT scan and endoscopic dissection available. A record of the dissection was obtained to allow the novice surgeon to compile the report. Interrater agreement regarding each variable of the classification systems was estimated through Cohen's kappa value. Cohen's kappa values of variables referring to the same anatomical subunit were matched to compare ABC with MBKC.

RESULTS

For both air spaces in front and behind the FSDP, interrater agreement values of the variables of the ABC were significantly higher than the corresponding variables of the MBKC.

CONCLUSION

This preclinical study demonstrates the potential of the ABC system. Although the ABC may improve preoperative anatomical assessment of the frontoethmoidal area, validation in a clinical setting is required.

Normal Anatomy and Anatomic Variants of the Paranasal Sinuses on Computed Tomography

It is imperative for all imaging specialists to be familiar with detailed multiplanar CT anatomy of the paranasal sinuses and adjacent structures. This article reviews the radiologically relevant embryology of this complex region and discusses the region-specific CT anatomy of the paranasal sinuses and surrounding structures. Radiologists also need to know the clinical implications of identifying preoperatively the numerous anatomic variations encountered in this region and prepare a structured report according to the expectations of the referring clinician.

Impairment of nasal airway under intermittent hypoxia during growth period in rats

OBJECTIVE

To clarify the influences of intermittent hypoxia (IH) on the growth and development of the midfacial area, including the nasal cavity, in growing rats.

DESIGN

Seven-week-old male Sprague-Dawley rats were divided into two groups: the experimental group (n=5), which was exposed to IH for 8h during light periods at a rate of 20 cycles/h (nadir, 4% O₂ to peak, 21% O₂ with 0% CO₂), and the control group (n=5), which was exposed to room air. After 3 weeks, the maxillofacial structures in both groups were evaluated with respect to the height, width, length, surface area, cross-sectional area, and volume of the nasal cavity using soft X-ray and micro-CT.

RESULTS

The experimental group showed a significantly smaller cross-sectional area and volume than did the control group. The surface area exhibited no significant differences between the two groups, although it tended to be smaller in the experimental group than in the control group. The nasal volume divided by the length of the tibia (for comparison with whole-body growth) was significantly smaller in the experimental group than in the control group.

CONCLUSIONS

These data suggest that IH exposure suppresses growth and development of the nasal cavity and may result in nasal breathing disturbance.

Consequences of evolution: is rhinosinusitis, like otitis media, a unique disease of humans?

We hypothesize that if otitis media is most likely primarily a human disease due to consequences of evolution, rhinosinusitis may also be limited to humans for similar reasons. If otitis media, with its associated hearing loss, occurred in animals in the wild, they probably would have been culled out by predation. Similarly, if rhinosinusitis occurred regularly in animals, they likely would have suffered from severely decreased olfactory abilities, crucial for predator avoidance, and presumably would likewise have been selected against evolutionarily. Thus, both otitis media and rhinosinusitis-common conditions particularly in infants and young children-appear to be essentially human conditions. Their manifestation in our species is likely due to our unique evolutionary trajectory and may be a consequence of adaptations, including adaptations to bipedalism and speech, loss of prognathism, and immunologic and environmental factors.

Sinus hypoplasia precedes sinus infection in a porcine model of cystic fibrosis

OBJECTIVES/HYPOTHESIS

Chronic sinusitis is nearly universal in humans with cystic fibrosis (CF) and is accompanied by sinus hypoplasia (small sinuses). However, whether impaired sinus development is a primary feature of loss of the cystic fibrosis transmembrane conductance regulator (CFTR) or a secondary consequence of chronic infection remains unknown. Our objective was to study the early pathogenesis of sinus disease in CF.

STUDY DESIGN

Animal/basic science research.

METHODS

Sinus development was studied in a porcine CF model.

RESULTS

Porcine sinus epithelia expressed CFTR and exhibited transepithelial anion transport. Disruption of the CFTR gene eliminated both. Sinuses of newborn CF pigs were not infected and showed no evidence of inflammation, yet were hypoplastic at birth. Older CF pigs spontaneously developed sinus disease similar to that seen in humans with CF.

CONCLUSIONS

These results define a role for CFTR in sinus development and suggest the potential of the CF pig as a genetic model of CF-sinus disease in which to test therapeutic strategies to minimize sinus-related CF morbidity.

Fetopathological aspects of holoprosencephaly

Holoprosencephaly (HPE) is a congenital central nervous system malformation estimated to occur in 1/250 conceptuses and 1/10,000 live births. While the severe forms, which are incompatible with life, are easier to detect in the prenatal period, the milder forms can remain unrecognised. As this can have serious consequences for the pregnancy and malformation carriers it is of crucial importance to find ways of timely detection of this pathological condition. The present study AIMED at finding an association of holoprosencephaly with facial dysmorphia and anomalies of visceral organs that would alert the physician to be very careful in making the prenatal diagnosis, which may require termination of pregnancy by medical indications.

MATERIAL AND METHODS

The study included 15 fetuses diagnosed with holoprosencephaly out of 2095 cases analysed post-mortem in the Fetopathology Clinic at the Centre for Maternity and Neonatology in the town of Tunisia over a period of 3 years (Oct. 2006 - Oct. 2009). The fetuses were analysed macro- and microscopically.

RESULTS

All forms of holoprosencephaly include elements of facial dysmorphism with the facial phenotypes of cyclopia, cebocephaly and ethmocephaly. It can be associated with specific internal organs anomalies, the hydrocephaly being the most common anomaly of the central nervous system. Our study suggested that holoprosencephaly can be correlated with craniofacial anomalies affecting the midfacial and medium craniovisceral structures.

CONCLUSION

The anatomical variations of HPE and the phenotypic facial correlations require a systematic and targeted study of central nervous system.

Revisiting human nose anatomy: phylogenic and ontogenic perspectives

This review suggests revisiting nose anatomy by considering the ethmoidal labyrinths as part of the olfactory nose and not as paranasal sinuses. Phylogenetically, the olfactory and respiratory organs of the most primitive vertebrates are separated. Exaptation, a mechanism of evolution, may explain the fusion of the olfactory and respiratory organs in dipnoi. The respiratory and olfactory noses remain anatomically separated by the transverse lamina in most mammals, whose olfactory labyrinth is a blind recess housing the ethmoturbinates. In humans, the partitioning between the olfactory cleft and the ethmoid labyrinth seems to be a consequence of ethmoid bone remodeling induced by the acquisition of an upright posture. The ethmoid bone is derived from the cartilaginous nasal capsule of primitive vertebrates and considered to be a highly conserved region among the bony elements of the skull base. It appears to be involved only in housing and protecting the olfactory function. During the early stages of human fetal development, rupture of the oronasal membrane leads to the integration of the primary olfactory sac in the future respiratory organ. The cartilaginous nasal capsule appears in the tissue under the brain and around the olfactory channels. Its early fetal development is classically regarded as the beginning of paranasal sinus formation. From phylogenic and ontogenic perspectives, it may be regarded as the development of the olfactory labyrinth as modified by the remodeling process of the human face and skull base. The endochondral bony origin of the ethmoid labyrinths makes them substantially different from the other paranasal sinuses.

Is it more reasonable to categorize frontal cells on the basis of their location rather than on their type?

Frontal cells appear in two locations-in the frontal recess and in the frontal sinus. The aim of this study was to analyze the anatomic and clinical differences between the frontal cells at each location. The author reviewed 487 left and right sides of coronal computed tomography (CT) scans of the sinuses obtained from 300 consecutively presenting patients (600 sides) who were being evaluated for chronic sinusitis. For the purposes of this study, the frontal cells were classified according to location; group A cells were located in the area of the frontal recess (Bent and Kuhn cell types I and II), and group B cells were those that had invaded the frontal sinus itself (Bent and Kuhn cell types III and IV). The presence or absence of frontal sinusitis and concha bullosa was determined, as was the degree of frontal sinus pneumatization. Analysis revealed statistically significant differences between group A and group B in all three parameters; the prevalence of frontal sinusitis and hyperpneumatization of the frontal sinus was higher in group B, and the prevalence of concha bullosa was higher in group A (all p < 0.05). These findings imply that it might be more reasonable both clinically and anatomically to categorize frontal cells based on their location rather than on their Bent and Kuhn type.

Triological thesis: concurrent endoscopic sinus surgery and cosmetic rhinoplasty: rationale, risks, rewards, and reality

OBJECTIVES/HYPOTHESIS

To examine the effect of concurrent endoscopic sinus surgery (ESS) on the postoperative course of cosmetic rhinoplasty (CR), identify any specific contraindications, and to develop more useful treatment regimen in patients undergoing concurrent ESS and CR.

STUDY DESIGN

Retrospective case-control study.

METHODS

Consecutive patients undergoing CR (performed by the principal investigator (PI) in a tertiary care academic practice) at the same operative setting as ESS from June 2004-June 2007 were identified. Additionally, patients undergoing CR (also by the PI) without ESS over the same time period (matched for gender, age, and rhinoplasty approach and techniques) were identified and used as control subjects. The office and hospital charts of these patients were reviewed for details of pre-, intra-, peri-, and postoperative care, preoperative CT scans as well as for patient and physician observations. Specifically noted were details regarding the type of cosmetic changes sought, course of symptoms of chronic sinusitis, prior treatment, surgical techniques used for both ESS and CR, and postoperative treatment with antibiotics and corticosteroids. Additionally, a literature review of articles describing concurrent CR and ESS was performed.

RESULTS

Thirteen patients were identified who underwent ESS at the same time as CR. There were no cases of cerebrospinal fluid leak, epistaxis, orbital complications, septal perforation, cellulitis or saddle nose deformity. No correlation was found between sinus surgery performed and need for revision surgery (CR or ESS) or postoperative infections. However, the time to patient reported resolution of postoperative nasal swelling was significantly higher in patients undergoing concurrent ESS/CR compared to CR only (dorsal swelling: 9.62 +/- 6.18 (ESS/CR) vs. 5.85 +/- 1.95 (CR) weeks, P = .0469; nasal tip swelling: 19.31 +/- 13.02 (ESS/CR) vs. 10.38 +/- 2.96 (CR) weeks, P = .0240, unpaired t test). The same relation held true for doctor noted postoperative edema (nasal dorsal edema: 10.62 +/- 7.32 (ESS/CR) vs. 6.31 +/- 2.72 (CR) weeks, P = .0582; nasal tip edema: 21.46 +/- 15.66 (ESS/CR) vs. 12.23 +/- 4.10 (CR) weeks, P = .0508, unpaired t test). Among patients who underwent concurrent ESS and CR, this time was highly correlated with the severity of sinus disease on preoperative CT scanning (r(2) = 0.8573, P < .0001). A greater need for postoperative corticosteroid injections in the ESS/CR group was suggestive but not statistically significant (30.8% vs. 0%, P = .0957).

CONCLUSIONS

While our data supports concurrent ESS and CR as safe, our findings suggest that the presence and treatment of concurrent sinonasal disease prolongs the patients' recovery from CR. This may be due to the effects of sinus pathology and manipulation of sinonasal venous and lymphatic drainage patterns or could be due to subclinical infectious soiling of rhinoplasty tissue planes. We recommend a two-team approach to promote excellent surgical technique, avoid surgeon fatigue, and enhance patient care. We recommend adequate medical management of chronic sinusitis prior to surgery, pre, intra and postoperative antibiotic coverage, appropriate postoperative sinus toilet beginning 1 week after surgery and careful and close patient follow-up to optimize results. Most importantly, we advocate close coordination of sinonasal and rhinoplastic care in a two-team approach to maximize care.

The paranasal sinuses: the last frontier in craniofacial biology

This special issue of the Anatomical Record explores the presence and diversity of paranasal sinuses in distinct vertebrate groups. The following topics are addressed in particular: dinosaur physiology; development; physiology; adaptation; imaging; and primate systematics. A variety of approaches and techniques are used to examine and characterize the diversity of paranasal sinus pneumatization in a wide spectrum of vertebrates. These range from dissection to histology, from plain X-rays to computer tomography, from comparative anatomy to natural experimental settings, from mathematical computation to computer model simulation, and 2D to 3D reconstructions. The articles in this issue are a combination of literature review and new, hypothesis-driven anatomical research that highlights the complexities of paranasal sinus growth and development; ontogenetic and disease processes; physiology; paleontology; primate systematics; and human evolution. The issue incorporates a wide variety of vertebrates, encompassing a period of over 65 million years, in an effort to offer insight into the diversity of the paranasal sinus complexes through time and space, and thereby providing a greater understanding and appreciation of these special spaces within the cranium.