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Physiology of the Nose and Paranasal Sinuses
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
The velocity of air increases as it passes the nasal valve, the narrowest part of the upper respiratory tract (Figure 26.1). With change of velocity, laminar flow turns into a turbulent flow, which results in reduced air velocity and prolonged contact of inspired air with the nasal mucosa, allowing the nose to perform its vital functions. Normally, 50% of air flows via the middle meatus. Septal deviations and turbinate hypertrophy may increase resistance and cause nasal obstruction. However, when resistance is too low, patients may suffer with paradoxical obstruction known as ‘empty nose syndrome’.
Management of Enlarged Turbinates
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Andrew C. Swift, Samuel C. Leong
However, total resection of the inferior turbinate does carry a risk of inducing the ‘empty nose syndrome (ENS)’ in which the patient complains of nasal obstruction in the absence of an obstructive cause (Figure 105.9).24 The pathophysiology is unclear but probably involves altered nasal receptor sensitivity, associated with humidity and conditioning of inhaled air; neuropsychological factors have also been suspected. Visible dryness or crusting are normally not seen. Should ENS occur after inferior turbinate resection, inserting a submucosal Medpor (Porex Surgical Inc) implant to effectively create a neo-turbinate has recently been described as a successful means of management.25
Intranasal trigeminal function in chronic rhinosinusitis: a review
Published in Expert Review of Clinical Immunology, 2023
Anna Kristina Hernandez, Thomas Hummel
Nasal obstruction is among the key symptoms of chronic rhinosinusitis [13,52]. Although the symptom is often attributed to a mechanical obstruction due to nasal polyps, other factors including trigeminal dysfunction have been proposed to contribute to the perception of impaired nasal airflow in CRS [20,21]. Interestingly, the perception of decreased nasal airflow has also been reported in patients with ‘empty nose syndrome’ suggesting that perceived nasal airflow is independent of nasal patency but related to mucosal sensitivity [55].
Perioperative nasal and paranasal sinus considerations in transsphenoidal surgery for pituitary disease
Published in British Journal of Neurosurgery, 2020
Lisa Caulley, Ravindra Uppaluri, Ian F. Dunn
Aggressive resection of the turbinates, an essential source of respiratory resistance, can result in paradoxical nasal obstruction, so-called empty-nose syndrome. Empty nose syndrome, a poorly recognized but devastating complication of excessive intranasal resections, is an iatrogenic disorder characterized as subjective poor nasal breathing despite a patent nasal airway.67,68 A lack of turbinate tissue creates an impaired sensation of nasal airflow while the distal respiratory structures (that is, the pharynx and lungs) and manometric flow studies will continue to indicate a fully patent airway.67 This conflicting information can lead patients to report a sensation of suffocating or constant dyspnea, and may result in a preoccupation with nasal breathing, poor concentration (aprosexia nasalis), chronic fatigue and depression. Furthermore, patients may suffer from hyposmia, sleep-disordered breathing, and squamous metaplasia of the remaining nasal mucosa due to excess exposure to dry and cold air.67 Empty nose syndrome is a rare, albeit possible, complication following endoscopic skull base surgery, although high quality evidence on this topic is lacking.69–71 Management of empty nose syndrome can be challenging. Primary interventions should focus on avoidance of superfluous resection of intranasal structures, a consideration to which surgeons should be particularly conscious of in the setting of endonasal skull base surgery where normal nasal structures are removed. Treatment goals in patients with empty nose syndrome should focus on open dialogue with patients regarding their symptoms, moisturization and reconstruction of nasal structures.67 A significant improvement in SNOT-20 and −25 scores following surgical intervention are reported in the majority of patients. However, clinical response varies among patients with up to 21% reporting only marginal improvement.68
Evaluation of nasal function after endoscopic endonasal surgery for pituitary adenoma: a computational fluid dynamics study
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Miao Lou, Luyao Zhang, Simin Wang, Ruiping Ma, Minjie Gong, Zhenzhen Hu, Jingbin Zhang, Yidan Shang, Zhenbo Tong, Guoxi Zheng, Ya Zhang
Over recent years, significant advances have been made in computational fluid dynamics (CFD) which can provide an accurate and non-invasive means of quantitative analysis of fluids, representing a popular method of the evaluation of nasal aerodynamics. Li et al. (2016) used CFD to study the influence of nasal septal perforation on functionality during inhalation and found that it not only caused airflow interference but also disrupted heating of the nasal cavity. Maza et al. (2019) found that nasal airflow patterns in patients with empty nose syndrome (ENS) following EEA were similar to those in non-EEA ENS patients, which were significantly different from those of EEA patients without the symptoms of ENS or healthy controls. Rhee et al. (2011) performed preoperative and postoperative CT scans of patients undergoing septoplasty and right inferior turbinate reduction (ITR) to establish three-dimensional models of nasal airways and virtual surgical models. Analysis by CFD suggests that virtual nasal surgery has considerable potential as a predictive tool, enabling surgeons to individualize the procedure using computer simulation techniques. Li et al. (2020) conducted a study on patients with nasal septum deviation (NSD) and found that the presence of concha bullosa on the non-deviated side of NSD patients resulted in more uniform air distribution between the bilateral nostrils. Moreddu et al. (2020) found that the nasal valve region plays a crucial role in warming the inhaled air of newborns. Lindemann et al. (2005) studied nasal airflow during inhalation after radical sinus surgery using numerical simulation and found that invasive sinus surgery resulted in decreased nasal air conditioning due to disturbed airflow patterns and decreased surface area relative to nasal volume. Moghadas et al. (2011) used computational modeling methods to study the effect of nasal septal deviation on nano/microparticle deposition in human nasal passages. The results demonstrated that, in addition to significant changes in airflow morphology, the deposition of nano and microparticles also changed significantly after nasal septoplasty or septal correction. Using a partial middle turbinectomy model, Zhao et al. (2014) found that although overall airflow and nasal obstruction had changed, no significant differences in flow rate, air flux distribution, or wall shear stress distribution were observed between the MTR and control models. In contrast, Dayal et al. (2016) observed significant impairment of nasal air conditioning after total middle turbinectomy and significant changes in local airflow distribution. Siu et al. conducted a CFD study to investigate the effect of different surgical techniques on nasal air conditioning under different environmental conditions (Siu et al. 2021). They found a reduced warming (or cooling) and humidification (or dehumidification) capacity under cooler temperatures in patients following inferior turbinate surgery. A literature review performed by Newsome et al. revealed that nasal surgeries inflicted some changes to the nasal mucosa and geometry that may result in decreased heating and humidification (Newsome et al. 2019).