The impact of thyroidectomy on obstructive sleep apnea: a systematic review and meta-analysis.

PURPOSE: Various thyroid pathologies are speculated to contribute to obstructive sleep apnea (OSA). The underlying mechanisms of the intricate relationship between OSA and thyroid structure and function, and whether thyroidectomy can alleviate OSA symptoms remain unclear. An assessment of the impact of thyroidectomy on OSA is warranted. METHODS: A systematic review of four electronic databases (PubMed (Medline), Embase, the Cochrane library, and ClinicalTrials.gov) was performed up to February 2022. The primary outcomes were preoperative and postoperative Apnea/Hypopnea Index (AHI), Epworth Sleepiness Scale (ESS), Berlin questionnaire scores, and continuous positive airway pressure (CPAP) use. A meta-analysis of continuous measures and odd ratios was conducted. Small-scale studies underwent a qualitative meta-analysis. RESULTS: Six cohort studies on 221 OSA patients who underwent thyroidectomies were included. The results showed that thyroidectomy was associated with significant reduction in postoperative AHI (Mean difference [MD], -6.39, 95% CI, -12.46 to -0.32), however, no significant association was found with CPAP withdrawal (Odd ratio [OR], 0.38, 95% CI, 0.12-1.18). Neither the Berlin questionnaire score (OR, 0.19, 95% CI, 0.03-1.17) nor the ESS improved postoperatively (MD, -1.04, 95% CI, -6.37 to 4.29). CONCLUSION: This meta-analysis provides a quantitative estimate for the effect of the thyroidectomy on OSA and suggests that thyroidectomy is associated with limited clinical improvement of polysomnographic measures. Future large-scale, well-designed prospective studies are necessary to validate these findings and to refine accordingly the preoperative assessment of both medical conditions individually and in combination.

The Interaction Between Craniofacial Computed Tomographic Dimensional Parameters and BMI in Obstructive Sleep Apnea.

INTRODUCTION: The impact of the dimensional parameters of the pharyngeal bony frame by its length, width and the position of the hyoid upon the severity of obstructive sleep apnea syndrome (OSAS) has not been investigated in depth. Interactions of those parameters with body mass index (BMI) and their overall reciprocal effect on OSAS severity have also not been established. MATERIALS AND METHODS: This retrospective cross-sectional study was conducted on 108 male OSAS patients followed in OSAS outpatient clinics between November 2014 and October 2015. They all underwent a polysomnography test, and an apnea-hypopnea index (AHI) was calculated. They also underwent an upper airway computerized tomographic scan in which three craniofacial parameters were evaluated: inter-pterygoid distance (IPD), hard palate-to-hyoid (HP-H) distance, and gnathion plane-to-hyoid (GP-H) distance. RESULTS: A longer pharynx and an inferiorly placed hyoid bone correlated with the AHI (r = 0.33, p = 0.001 and r = 0.226, p = 0.03, respectively). GP-H correlated with body mass index (BMI) (r = 0.3243, p < 0.001), while HP-H and IPD did not. We found an interaction between BMI and HP-H, but none between GP-H and BMI. IPD did not correlate with OSAS severity, but it correlates with the age of the OSAS patients (r = 0.235, p = 0.015). CONCLUSION: Pharynx length and hyoid position have significant effects upon OSAS severity, and they interact differently with BMI in terms of those effects. Hard palate width increases with age but has no correlation with OSAS severity.

The effect of nocturnal CPAP therapy on the intraocular pressure of patients with sleep apnea syndrome.

PURPOSE: Few studies have documented that nocturnal continuous positive airway pressure (CPAP) therapy is associated with an increase in intraocular pressure (IOP) in patients with severe obstructive sleep apnea syndrome (OSAS). We re-examined the effect of CPAP therapy on the IOP of OSAS patients. METHODS: The IOP of two different groups of newly diagnosed OSAS patients was compared at their first sleep lab exam without CPAP treatment (non-CPAP treated group; n = 20) and at the second sleep lab exam with CPAP treatment (CPAP treated group; n = 31). The sleep lab exam (sleep period: from 11:00 p.m. until 6:00 a.m.) included IOP measurements, a complete ophthalmologic exam, and nocturnal hemodynamic recordings. The IOP was measured serially using rebound tonometer (IOP; ICARE® PRO) performed while in sitting and supine positions before, during, and after the sleep period. We compared the difference in IOP of CPAP and non-CPAP groups. RESULTS: The mean IOP of the CPAP and non-CPAP groups measured in sitting position before the sleep period was 13.33 ± 2.04 mmHg and 14.02 ± 2.44 mmHg, respectively (p = 0.9). Assuming a supine position for 1 minute significantly increased the IOP by 1.93 mmHg and 2.13 mmHg for both the non-CPAP and CPAP groups (paired t-test; p = 0.02, p = 0.001 respectively), but this IOP rise showed no difference between the two groups. The IOP increased significantly further after 7 hours of sleep in the supine position, and the mean IOP of the CPAP and non-CPAP groups was 19.2 ± 5.68 mmHg and 19.69 ± 5.61 mmHg respectively (independent t-test; p = 0.74). The rise in IOP for both groups was not correlated with any hemodynamic parameters. Three OSAS patients with glaucoma treated with CPAP had mean IOP of 23.75 mmHg after 7 hours of sleep. CONCLUSIONS: OSAS patients have a significant rise in IOP during the sleep period when comparing measurements before and after the sleep period; however, CPAP therapy did not affect the measured IOP. The presented findings suggest that in terms of IOP, CPAP is safe for non-glaucomatous patients, but this may not hold true for glaucomatous patients.

Tongue base ultrasound: a diagnostic tool for predicting obstructive sleep apnea.

OBJECTIVES: We assessed the value of an ultrasound (US) examination in the diagnostic workup of patients with sleep-related breathing disorders by correlating US measurements with known parameters for the presence and severity of obstructive sleep apnea. METHODS: Forty-one male patients who complained of snoring and/or daytime somnolence participated. The diagnostic protocol included history-taking, physical examination, polysomnography, and transcervical US examination of the tongue. The US results were compared with all of the other parameters. RESULTS: The US imaging was reliable for demonstrating anatomic structures of the tongue base, discriminating between muscle, mucosa, and blood vessels. The lingual arteries were clearly visualized entering the tongue base at its lower lateral borders. There was a significant relationship between the severity of sleep-related breathing disorders (measured by polysomnography) and the width of the lower tongue base (measured as the distance between the lingual arteries). The distance between the lingual arteries also correlated with physical examination findings and patient complaints of daytime somnolence and the sensation of choking during the night. CONCLUSIONS: Tongue base width, measured by US, may influence the severity of obstructive sleep apnea. This is the first demonstration of the possible role of US examination, an inexpensive, noninvasive, and non-irradiating office procedure, in the diagnostic workup for sleep-related breathing disorders.

AFM study of microstructures on the cornea of the compound eye and ocelli of the hornet Vespa orientalis (Insecta, Hymenoptera).

The present study describes a novel structure occurring on the cornea in the compound eye and the ocellus of the Oriental hornet. This description is based on observations carried out via scanning electron microscopy (SEM) and primarily via atomic force microscopy (AFM). We report herein that the vespan cornea is densely covered with cupola-shaped protrusions, which in the compound eye have bases about 0.2 microm in diameter and an average height of 0.03 microm while upon the ocelli their diameter is rather variable, with some measuring 0.2-0.3 microm, and a length of submicrons to microns. Interspersed among the brief, cupola-shaped structures there are winding, longer structures whose height appears uniform at around 0.03 microm. It appears that the structures are formed from the epicuticular layer of the cornea and we conjecture that in both the compound eye and in the ocelli they serve to enhance the absorption of light, as well as to reduce light reflection.