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Computational fluid dynamics and trigeminal sensory examinations of empty nose syndrome patients.

ABSTRACT: The precise pathogenesis of empty nose syndrome (ENS) remains unclear. Various factors such as nasal aerodynamics and sensorineural dysfunction have been suspected, although evidence is limited. This study reported the first examination of both nasal aerodynamics and trigeminal sensory factors in actual ENS patients.Prospective case control.We enrolled six patients diagnosed with ENS. Three patients had pre- and post-inferior turbinate (IT) reduction computed tomography scans, which allowed comparison of their nasal aerodynamics changes through computational fluid dynamic (CFD) simulation. Their symptoms were confirmed through Sino-nasal Outcome Test-22, ENS 6-item Questionnaire, acoustic rhinometry, and rhinomanometry findings. Nasal trigeminal sensitivity that potentially mediates their perception of airflow was assessed via menthol lateralization detection thresholds (LDT) and compared with 14 healthy controls.Post-surgical reductions in nasal resistance were observed and significantly lower than normal (P < 0.05). Computational fluid dynamic analysis showed that, paradoxically for all ENS patients, IT reduction did not draw more airflow to the airway surrounding the ITs, but rather resulted in nasal airflow forming into a narrow jet toward the middle meatus region, leaving the airway surrounding the IT with significantly reduced airflow intensity and air-mucosal interactions (inferior region flow percentage reduced from 35.7% ± 15.9% to post-surgery 17.7% ± 15.7%, P < 0.05; inferior wall-shear-stress reduced from 7.5 ± 4.2 × 10-2 Pa to 3.4 ± 3.1 × 10-2 Pa, P < 0.01). Empty nose syndrome patients also had significantly impaired menthol LDT compared to healthy controls (P < 0.005).The results indicated that a combinatory of factors, including paradoxically distorted nasal aerodynamic, impaired sensorineural sensitivity, and potential predisposing conditions, may contribute to the development of ENS.3b. Laryngoscope, 127:E176-E184, 2017.

SUBMITTER: Li C

PROVIDER: S-EPMC5445013 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Computational fluid dynamics and trigeminal sensory examinations of empty nose syndrome patients.

Li Chengyu C Farag Alexander A AA Leach James J Deshpande Bhakthi B Jacobowitz Adam A Kim Kanghyun K Otto Bradley A BA Zhao Kai K

The Laryngoscope 20170309 6

<h4>Objective</h4>The precise pathogenesis of empty nose syndrome (ENS) remains unclear. Various factors such as nasal aerodynamics and sensorineural dysfunction have been suspected, although evidence is limited. This study reported the first examination of both nasal aerodynamics and trigeminal sensory factors in actual ENS patients.<h4>Study design</h4>Prospective case control.<h4>Methods</h4>We enrolled six patients diagnosed with ENS. Three patients had pre- and post-inferior turbinate (IT) ...[more]

PMID: 28278356

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Project description:BackgroundAbnormal nasal aerodynamics or trigeminal functions have been frequently implicated in the symptomology of empty nose syndrome (ENS), yet with limited evidence.MethodsIndividual computed tomography (CT)-based computational fluid dynamics (CFD) was applied to 27 ENS patients to simulate their nasal aerodynamics and compared with 42 healthy controls. Patients' symptoms were confirmed with Empty Nose Syndrome 6-item Questionnaire (ENS6Q), 22-item Sino-Nasal Outcome Test (SNOT-22), and Nasal Obstruction Symptom Evaluation (NOSE) scores. Nasal trigeminal sensitivity was measured with menthol lateralization detection thresholds (LDTs).ResultsENS patients had significantly lower (∼25.7%) nasal resistance and higher (∼2.8 times) cross-sectional areas compared to healthy controls (both p < 0.001). Despite inferior turbinate reductions, CFD analysis demonstrated that ENS patients had increased airflow concentrated in the middle meatus region (66.5% ± 18.3%) compared to healthy controls (49.9% ± 15.1%, p < 0.0001). Significantly less airflow (25.8% ± 17.6%) and lower peak wall shear stress (WSS) (0.58 ± 0.24 Pa) were found in the inferior meatus (vs healthy: 36.5% ± 15.9%; 1.18 ± 0.81 Pa, both p < 0.05), with the latter significantly correlated with the symptom scores of ENS6Q (r = -0.398, p = 0.003). Item-wise, complaints of "suffocation" and "nose feels too open" were also found to be significantly correlated with peak WSS around the inferior turbinate (r = -0.295, p = 0.031; and r = -0.388, p = 0.004, respectively). These correlations were all negative, indicating that less air-mucosal stimulations resulted in worse symptom scores. ENS patients (n = 12) also had impaired menthol LDT when compared to healthy controls (p < 0.0001).ConclusionThis is the first CFD examination of nasal aerodynamics in a large cohort of ENS patients. The results indicated that a combination of loss of neural sensitivity and poorer inferior air-mucosal stimulation may potentially lead to ENS symptomology.

Project description:BackgroundEmpty nose syndrome (ENS) remains highly controversial, with aggressive inferior turbinate reduction (ITR) or mucociliary dysfunction frequently implicated. However, the appropriate degree of ITR is highly debatable.MethodsWe applied individual computed tomography (CT)-based computational fluid dynamics (CFD) to 5 patients receiving relatively aggressive ITR but with no ENS symptoms, and compared them to 27 symptomatic ENS patients who all had histories of aggressive ITRs, and 42 healthy controls. Patients' surgical outcomes were confirmed with 22-item Sino-Nasal Outcome Test (SNOT-22) (ITR: 6.40 ± 4.56; ENS: 58.2 ± 15.9; healthy: 13.2 ± 14.9), Nasal Obstruction Symptom Evaluation (NOSE) scores (ITR: 4.00 ± 2.24; ENS: 69.4 ± 17.1; healthy: 11.9 ± 12.9), and Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) (≥11 for ENS).ResultsBoth aggressive ITR without ENS symptoms and symptomatic ENS patients had significantly lower nasal resistance (ITR: 0.059 ± 0.020 Pa·s/mL; ENS: 0.052 ± 0.015 Pa·s/mL; healthy: 0.070 ± 0.021 Pa·s/mL) and higher cross-sectional areas surrounding the inferior turbinate (ITR: 0.94 ± 0.21 cm2 ; ENS: 1.19 ± 1.05 cm2 ; healthy: 0.42 ± 0.22 cm2 ) than healthy controls. The lack of significant differences among patient groups indicated similar degrees of surgeries between ITR with and without ENS symptom cohorts. However, symptomatic ENS patients have paradoxical significantly less airflow in the inferior meatus (ITR: 47.7% ± 23.6%; ENS: 25.8% ± 17.6%; healthy: 36.5 ± 15.9%; both p < 0.01), but higher airflow around the middle meatus (ITR: 49.7% ± 22.6%; ENS: 66.5% ± 18.3%; healthy: 49.9% ± 15.1%, p < 0.0001) than aggressive ITR without symptoms and controls. Aggressive ITR patients have increased inferior meatus airflow as expected (p < 0.05). This imbalanced airflow produced less inferior wall-shear-stress distribution among symptomatic ENS patients only (ITR: 42.45% ± 11.4%; ENS: 32.2% ± 12.6%; healthy: 49.7% ± 9.9%). ENS patients (n = 12) also had impaired nasal trigeminal function, as measured by menthol lateralization detection thresholds (ITR: 15.2 ± 1.2; ENS: 10.3 ± 3.9; healthy: 13.8 ± 3.09, both p < 0.0001). Surprisingly, aggressive ITR patients without ENS symptoms have better menthol lateralization detection thresholds (LDTs) than healthy controls.ConclusionAlthough turbinate tissue loss is linked with ENS, the degree of ITR that might distinguish postoperative patient satisfaction in their nasal breathing vs development of ENS symptoms is unclear. Our results suggest that a combination of distorted nasal aerodynamics and loss of mucosal sensory function may potentially lead to ENS symptomology.

Project description:ObjectivesPatients with empty nose syndrome typically experience paradoxical nasal congestion, nasal dryness, epistaxis, and suffocation. Conservative management is generally preferred for empty nose syndrome. However, some patients continue to experience persistent symptoms. When symptoms do not resolve, surgical options are considered. Therefore, we reviewed the surgical and regenerative treatment options for empty nose syndrome.MethodsPubMed, Embase, Scopus, Cochrane Register of Controlled Trials, and Google Scholar were searched from the earliest date provided in the database until December 2022. This review included studies that assessed treatment outcomes using patient symptom scores, including the Sino-Nasal Outcome Test (SNOT-20, -22, and -25) and the Empty Nose Syndrome 6-Item Questionnaire, supplemented by various clinical examinations.ResultsTwenty-eight studies were analyzed. Various materials were utilized, including submucosal injectable materials, allografts/xenografts/cadaveric implants, autologous implants, and synthetic implants. The polyethylene implant was the most commonly used (23.3%), followed by autologous, homologous, or cadaveric costal cartilage (20%). The anterior-inferior lateral nasal wall was the most frequent site of administration. Most studies indicated that surgical intervention led to significant improvements in clinical outcomes, as evidenced by endoscopic exams, acoustic rhinometry, and computed tomography scans, along with patient-reported enhancements in nasal symptoms, psychological well-being, and overall health-related quality of life. However, several studies found no improvement in certain psychological-related questionnaires or saccharin transit times. The average follow-up duration was 12.0 months (range, 2.0-27.6 months). Only two studies reported postoperative adverse effects.ConclusionSeveral surgical options and recent tissue regeneration techniques have demonstrated efficacy in treating empty nose syndrome. However, more detailed investigations involving a larger number of participants and a randomized control study are necessary to establish a standardized treatment protocol for patients with empty nose syndrome.

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Computational fluid dynamics and trigeminal sensory examinations of empty nose syndrome patients.

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Computational fluid dynamics and trigeminal sensory examinations of empty nose syndrome patients.

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