Obstructive sleep apnea syndrome: preoperative radiologic evaluation

Predictors of Success of Pharyngeal Surgery in the Treatment of Obstructive Sleep Apnea: A Narrative Review

(1) Background: This narrative review aims to explore the predictors of success for pharyngeal surgery in the treatment of obstructive sleep apnea (OSA). An extensive literature search was conducted, identifying relevant studies published up to June 2023, utilizing various databases and key search terms related to OSA, surgical interventions, and predictors of success. The review encompasses both retrospective and prospective studies, case series, and cohort studies to provide a broad understanding of the topic; (2) Methods: Review of English scientific literature on phenotypes of OSA related to predictors of success of pharyngeal surgery; (3) Results: Of 75 articles, 21 were included, in these the following were determined to be factors for surgical success: body mass index (BMI) (8 articles), apnea/hypopnea index (AHI) (8 articles), cephalometry (8 articles), palatine tonsil size (7 articles), Modified Mallampati score (2 articles), genioglossus electromyography (2 articles), Friedman score or upper airway anatomy (3 articles), nasopharyngolaryngoscopy (2 articles), drug-induced sleep endoscopy (DISE) (1 article), oral cavity anatomy (1 article) and oxygen desaturation index (ODI) (1 article); (4) Conclusions: The lack of standardized protocols for the indication of pharyngeal surgery is a reality, however identifying known predictors of surgical success may facilitate homogenizing indications.

Cephalometric and fiberoptic evaluation as a case-selection technique for obstructive sleep apnea syndrome (OSAS)

In order to obtain relatively simple and useful parameters to estimate the severity of obstructive sleep apnea syndrome (OSAS), cephalometric and fiberoptic studies were performed in 64 clinical cases previously diagnosed with either OSAS or snoring. Fourteen cephalometric parameters, 13 parameters derived from physical examination and 18 fiberoptic parameters were compared with the apnea index (AI), the apnea-hypopnea index and lowest SaO2 values. Statistically significant correlations were found between the Al and the shortest linear distance from the posterior line of the soft palate to the posterior pharyngeal wall measured along a line parallel to the supramentale-Gonion line (PAS-epipharynx distance), the distance from the mandibular plane to the most anterior and superior point on the body of the hyoid bone obtained from cephalometry (MP-H distance) and the degree of redundancy of mucosa in the arytenoid/aryepiglottic fold obtained from videoendoscopy. An increased Al was observed when the PAS-epipharynx distance was < 7 mm and there was 100% obstruction in Muller's maneuver at the palate level (supine), the MP-H distance was > 27.4 mm and the mucosa of the arytenoid/aryepiglottic fold was markedly redundant. As these three parameters are relatively easy to obtain on an outpatient basis, it is suggested that they could be used in an outpatient setting to provide a good prediction of the severity of OSAS.

Differential diagnosis of obstructive sleep apnea syndrome patients and snorers using cephalograms

Severe snoring is thought by many to be an early stage of obstructive sleep apnea syndrome (OSAS), but the anatomical relation between snoring and OSAS, if any, has remained unclear. To compare the morphology of the airway between snorers and OSAS patients for possible similarities, we conducted a cephalometric analysis of Japanese OSAS patients (n=10), habitual snorers (n=10), and non-snoring controls (n=50). There was no significant difference in SNB (the angle formed by the sella, nasion and point B) between OSAS patients and the control subjects. Obstructive sleep apnea syndrome patients tended to have an anteriorly positioned maxilla, and an anteroposterior misalignment between the maxilla and mandible. There was also a tendency toward skeletal openbite. Both OSAS patients and snorers had large tongues and large soft palates, thus causing constriction of the airway with resultant smaller airway diameter and smaller airway surface area. Significant differences between OSAS patients and snorers were found in thickness and length of soft palate surface area, and thickness, length, and position of the hyoid bone. These results suggest that cephalographic measurements may be of considerable use in determining the seriousness of a patient's condition.

Difficult laryngoscopy and cephalometric roentgenograms in obstructive sleep apnea syndrome patients undergoing uvulopalatopharyngoplasty

We retrospectively studied the incidence of difficult laryngoscopy in 53 subjects with obstructive sleep apnea syndrome (OSAS) undergoing uvulopalatopharyngoplasty (UPPP) and 72 subjects with chronic otitis media undergoing tympanoplasty (control group). The incidence of difficult laryngoscopy in the UPPP group was significantly higher than in the control group (18.9%vs 4.2%,P<0.001). To analyze the anatomical findings of difficult laryngoscopy in UPPP patients, cephalometric roentgenograms were compared between patients in whom direct laryngoscopy was difficult (difficult patients,n=10) and patients in whom direct laryngoscopy was not difficult (nondifficult patients,n=43). Cephalometric atlanto-occipital distance (cAOD) was less than 4mm in 80% of the difficult patients, and there were significant differences between the difficult patients and the nondifficult patients (2.8±3.3 mmvs 6.7±3.0 mm, mean ±SD,P<0.001). There were significant differences in cephalometric effective mandibular length/cephalometric posterior depth of mandible ratio (cEML/cPDM) between the difficult patients and the nondifficult patients (4.0±0.6vs 4.5 ±0.8,P<0.01); however, the calculation of cEML/cPDM was more difficult than cAOD. We concluded that OSAS patients undergoing UPPP are at high risk for difficult laryngoscopy, and that cAOD calculated from cephalometric roentgenograms is an easy and sensitive predictive indicator for the estimation of difficult laryngoscopy.

Videoradiography of patients with habitual snoring and/or sleep apnea. Technical description and presentation of videoradiographic results during sleep concerning occurrence of apnea, type of apnea, and site of obstruction

PURPOSE

The videoradiographic examination described was designed for habitual snorers and sleep apnea syndrome (SAS) patients and was performed during wakefulness and sleep. During wakefulness the purpose was to reveal any dysfunction in deglutition and speech as well as morphologic abnormalities. The purpose during sleep, which usually was induced by low-dose midazolam intravenously, was to reveal the site and form of obstruction in obstructive sleep apnea patients and the site of snoring in habitual snorers.

MATERIAL

The preoperative results of 104 patients are presented. In 57 patients who had apneas, the occurrence and type of apnea could be determined.

RESULTS AND CONCLUSION

A continuous recording over some minutes gave a rough estimate of the degree of SAS and mean duration of apnea. Although much information on SAS can be obtained by this method, it cannot replace polygraphic sleep recording in the investigation of habitual snorers and SAS patients. However, these 2 methods are complementary and can be performed simultaneously as polygraphic videoradiography.

Brief airway obstructions during sleep in infants with breath-holding spells

We investigated the possibility that infants with breath-holding spells have breathing disorders during sleep. Seventy-one breath holders with a median age of 14 weeks were selected from a well babies clinic because of their histories: 34 infants without loss of consciousness, and 37 with loss of consciousness (21 of the latter had had cyanotic spells, 14 pallid spells, and 2 combined cyanotic and pallid spells). For each breath holder, one control infant without a history of breath holding was chosen from the same clinic. All infants were healthy and had no known cause of disrupted breathing during sleep. Their histories indicated that the breath holders were covered with sweat during sleep (p = 0.005) or wakefulness (p = 0.006) significantly more often than were the control infants. The infants were studied during a one-night monitoring session, and the 142 sleep recordings were analyzed without knowledge of the history. The breath holders had significantly less nonrapid eye movement (stage III) sleep, more indeterminate sleep, more arousals, and more sleep-stage changes than the control infants had. Central apneas were evenly distributed in the two groups. Airway obstructions were found in 41 breath holders and six control infants; the obstruction lasted longer in the breath holders. The infants with airway obstruction during sleep snored more often (p = 0.023) and sweated more (p = 0.035) during sleep. The water evaporation rate, measured on the forehead with an evaporation meter, was significantly greater in the breath holders (p = 0.001). Ocular compression induced longer asystoles in the infants with pallid syncopes than in either those with cyanotic syncopes (p = 0.036) or those without loss of consciousness (p = 0.031). We conclude that the obstructed breathing during both wakefulness and sleep could be related to a common immature breathing control.