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

["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.

Nasopharyngeal morphology contributes to understanding the "muddle in the middle" of the Pleistocene hominin fossil record

The late archeologist Glynn Isaac first applied the term "muddle in the middle" to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundaries as a source of traits that may inform this unclear period of human evolution. The nasopharynx lies at the nexus of several vital physiological systems, yet relatively little is known about its importance in human evolution. We analyzed a geographically diverse contemporary Homo sapiens growth series (n = 180 adults, 237 nonadults), Homo neanderthalensis (La Chapelle aux Saints 1, La Ferrassie 1, Forbes Quarry 1, Monte Circeo 1, and Saccopastore 1), mid-Pleistocene Homo (Atapuerca 5, Kabwe 1, Petralona 1, and Steinheim 1), and two Homo erectus sensu lato (KNM-ER 3733 and Sangiran 17). Methods include traditional (Analysis 1) and 3D geometric morphometric analysis (Analysis 2). H. erectus exhibited tall, narrow nasopharyngeal shape, a robust, ancestral morphology. Kabwe 1 and Petralona 1 plotted among H. sapiens in Analysis 2, exhibiting relatively shorter and vertical cartilaginous Eustachian tubes and vertical medial pterygoid plates. Atapuerca 5 and Steinheim 1 exhibited horizontal vomeral orientation similar to H. neanderthalensis, indicating greater relative soft palate length and anteroposterior nasopharynx expansion. They may exhibit synapomorphies with H. neanderthalensis, supporting the accretionary hypothesis. Species-level differences were found among H. sapiens and H. neanderthalensis, including relatively longer dilator tubae muscles and extreme facial airorhynchy among Neanderthals. Furthermore, H. neanderthalensis were autapomorphic in exhibiting horizontal pterygoid plate orientation similar to human infants, suggesting that they may have had inferiorly low placement of the torus tubarius and Eustachian tube orifice on the lateral nasopharyngeal wall in life. This study supports use of osseous nasopharyngeal boundaries both for morphological characters and understanding evolution of otitis media susceptibility in living humans.

Ancestry-based variation in maxillary sinus anatomy: Implications for health disparities in sinonasal disease

Paranasal sinus drainage is mediated by mucociliary transport and gravity. However, human orthograde posture, along with the superior positioning of the maxillary sinus (MS) ostium, increases reliance on the mucociliary system. Previous research has thus suggested that differences in MS size and shape may impede mucociliary clearance, potentially contributing to disparities in sinusitis susceptibility. To further investigate this hypothesis, this study collected 29 three-dimensional (3D) coordinate landmarks and seven linear measurements of MS morphology from 167 computed tomography (CT) scans of crania of European, East Asian, or Equatorial African ancestry. MANOVA results reveal the Asian-derived individuals are characterized by both a significantly taller MS (F = 14.15, p <  0.0001) and a significantly greater distance from the MS floor to the ostium (F = 17.22, p <  0.0001) compared to those of European and African ancestry. A canonical variate (CV) analysis conducted on 3D landmark data provides corroborative results, distinguishing Asian-derived individuals predominantly on the basis of a relatively lower MS floor. As a greater distance between the MS floor and ostium may impede mucociliary clearance, our results suggest MS anatomy may be a more prominent factor in chronic sinusitis among individuals of Asian ancestry compared to those of European and African ancestries. This provides tentative evidence of an anatomical etiology for chronic sinusitis even in the absence of anatomical variants/abnormalities (e.g., nasal polyps, concha bullosa, Haller's cells, and Agger nasi cells). Further research into the relationship between MS anatomy and sinusitis, in addition to socioeconomic inequalities of healthcare, is warranted to continue evaluating possible contributions to health disparities.

Identification of critical windows in early development of human upper respiratory tract and middle ear disease

Otitis media (OM) or middle ear disease is a prevalent pediatric condition generally related to early growth of the cartilaginous Eustachian tube (CET). This study used a developmental series of dry crania to reconstruct CET and dilator tubae (DT, the muscle opening the CET) morphology. Timing and directionality of CET and upper respiratory tract (URT) growth were investigated. Traditional and 3D geometric morphometrics (GM) were used to assess bony landmarks on the crania. The series was divided using dental eruption into seven growth stages ranging from before eruption of deciduous dentition (approximately the first 6 postnatal months) to eruption of the first permanent maxillary molar (after approximately 6 years). Bony endpoints of the CET and DT were used to calculate their morphology. GM analysis showed substantial shape differences between newborns, early infants, and all later developmental stages. Univariate measures showed the largest growth change between birth and 6 months. Subsequently, CET morphology changed little in the latter half of year 1, instead maturing gradually until approximately 3 years whereas DT relative length and orientation finish growth by the end of year 1. Incongruence in slower CET growth and faster DT growth could impact CET function between 6 and 12 months and be a contributing factor of OM. Tubal aeration may improve after this time when both CET and DT morphology mature, coinciding with clinically reported drop-off in ear infections.

Bacterial transportable toxins of the nasopharyngeal microbiota in multiple sclerosis. Nose-to-brain direct

Intranasal administration delivers molecules directly to the brain bypassing the blood-brain barrier. Three distinct routes of access have been identified; olfactory, trigeminal and via the paranasal sub-mucosa of the posterior sinuses. Consequently, environmental toxins may access the CNS directly to induce inflammatory and degenerative disease. They may also activate bacterial species of the nasal mucosal microbiome to release both immune-deviating cell wall antigens and transportable neurotoxins with local direct access to the CNS. Evidence is reviewed that toxins of the nasal bacterial microbiota may be directly implicated in the inflammatory and degenerative pathogenesis of multiple sclerosis.

Reconstructing the Neanderthal Eustachian Tube: New Insights on Disease Susceptibility, Fitness Cost, and Extinction

Neanderthals are among the best studied and yet most enigmatic fossil human groups with aspects of their anatomy and functional morphology remaining poorly understood. We present the first anatomical reconstruction of the Neanderthal cartilaginous Eustachian tube (CET), a vital component of the upper respiratory tract and nexus for the middle ear and postnasal airway. The Eustachian (auditory, pharyngotympanic) tube, comprised of a bony and cartilaginous (CET) portion, is integral to normal physiological functions such as middle ear aeration and pressure equilibration. Findings indicate that Neanderthal tubal morphology may have predisposed them to high rates of middle ear disease (otitis media [OM]). In living humans, mechanical CET dysfunction underlies OM in infants and young children, with sequelae including hearing loss, meningitis, and pneumonia. Despite proven linkage of CET malfunction with OM, the role of CET morphology in Neanderthal health and disease remains unstudied. We reconstructed Neanderthal CET morphology, comparing their crania to a modern human growth series. Methods included geometric morphometrics and univariate measures among Procrustes-fitted coordinates. Results showed Neanderthal adults exhibiting primitively tall and narrow nasopharynges with infant-like horizontal CET and choanal orientation. As horizontal CET orientation is associated with increased OM incidence in infants and children until around age six, its appearance in Neanderthal adults strongly indicates persistence of high OM susceptibility at this time. This could have compromised fitness and disease load relative to sympatric modern humans, affecting Neanderthals' ability to compete within their ecological niche, and potentially contributing to their rapid extinction. Anat Rec, 302:2109-2125, 2019. © 2019 American Association for Anatomy.

Cranial Indicators Identified for Peak Incidence of Otitis Media

Acute otitis media (AOM) is one of the most common pediatric conditions worldwide. Peak age of occurrence for AOM has been identified within the first postnatal year and it remains frequent until approximately six postnatal years. Morphological differences between adults and infants in the cartilaginous Eustachian tube (CET) and associated structures may be responsible for development of this disease yet few have investigated normal growth trajectories. We tested hypotheses on coincidence of skeletal growth changes and known ages of peak AOM occurrence. Growth was divided into five dental eruption stages ranging from edentulous neonates (Stage 1) to adults with erupted third maxillary molars (Stage 5). A total of 32 three-dimensional landmarks were used and Generalized Procrustes Analysis was performed. Next, we performed principal components analysis and calculated univariate measures. It was found that growth change in Stage 1 was the most rapid and comprised the largest amount of overall growth in upper respiratory tract proportions (where time is represented by the natural logarithmic transformation of centroid size). The analysis of univariate measures showed that Stage 1 humans did indeed possess the relatively shortest and most horizontally oriented CET's with the greatest amount of growth change occurring at the transition to Stage 2 (eruption of deciduous dentition at five postnatal months, commencing peak AOM incidence) and ceasing by Stage 3 (approximately six postnatal years). Skeletal indicators appear related to peak ages of AOM incidence and may contribute to understanding of a nearly ubiquitous human disease. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1721-1740, 2017. © 2017 Wiley Periodicals, Inc.

The evolution and development of human swallowing: the most important function we least appreciate

As mammals evolved, the larynx accrued added importance in new activities such as effectuating intra-abdominal pressure control during the transition from egg-laying to birthing and control of intrathoracic stabilization as movement of the upper limb required rib stabilization during climbing. The proper development of the larynx during the embryonic period is crucial to its later normal function. The permanent intersection of the respiratory and digestive pathways has created a de novo aerodigestive tract; a first of its kind in mammals. The lowered position of the human larynx has provided a greatly expanded supralaryngeal portion of the pharynx.