A retrospective study: does upper airway morphology differ between non-positional and positional obstructive sleep apnea?

Abstract

ObjectiveThe objective of this study was to explore the differences in upper airway morphology between positional (POSA) and non-positional (NPOSA) obstructive sleep apnea.MethodsThis retrospective study enrolled 75 patients (45 NPOSA and 30 POSA) who underwent polysomnography (PSG) and computed tomography (CT). The differences in, and relationships of, the PSG values and CT data between POSA and NPOSA were analyzed.ResultsSignificant (p < 0.05) differences between the two groups were found in the apnea/hypopnea index (AHI), lateral-AHI (L-AHI), soft palate length (SPL), cross-sectional palatopharyngeal area, and the coronal diameter (CD) of the palatopharyngeal area at the narrowest part of the glossopharynx, which were all higher in POSA, except for SPL, AHI, and L-AHI. L-AHI was correlated with the cross-sectional area (r = − 0.306, p = 0.008) and CD (r = − 0.398, p < 0.001) of the palatopharyngeal area, the cross-sectional area (r = − 0.241, p = 0.038) and CD (r = − 0.297, p = 0.010) of the narrowest level of the glossopharynx, the CD of the glossopharynx (r = 0.284, p = 0.013), body mass index (BMI, r = 0.273, p = 0.018), SPL (r = 0.284, p = 0.014), and vallecula-tip of tongue (r = 0.250, p = 0.030). The SPL and CD at the narrowest part of the glossopharynx were included in the simplified screening model.ConclusionsIn NPOSA, the CD of the upper airway was smaller, and the soft palate was longer, than in POSA. These differences may play significant roles in explaining the main differences between NPOSA and POSA.

Obstructive Sleep Apnea: Do Positional Patients Become Nonpositional Patients With Time?

“…The increase in AHI-LAT was over twelve times greater in PPs who converted to NPPs compared to those who stayed as PPs. Furthermore, a recent Asian study comparing the upper airway morphology of PPs to that of NPPs supports the idea that AHI-LAT is a sensitive parameter describing OSA positionality 22 . The authors found that in NPPs the coronal diameter of the upper airway is smaller and the soft palate is longer compared to PPs.…”

“…In addition, the AHI-LAT was associated with soft palate length. More the length of the soft palate exceeded 35.4 mm, the greater was the risk to become NPP 22 . Since the increase in the length of soft palate is most probably related, at least partially, to weight gain, these results also support the modulatory effect of weight change on positional OSA 8 .…”

“…Therefore, NPPs suffers most often severe OSA as they have high number of breathing abnormalities independently of sleeping posture. The explanation how a PP turns into an NPP due to weight gain is based on the work of Saigusa et al 24 , (and supported by a recent Chinese study 22 ), in which three-dimensional upper airway morphology analysis was performed. They showed that PPs, in comparison to NPPs, have a smaller soft tissue volume in the lateral pharyngeal walls allowing PPs to breath without major difficulties while sleeping in the lateral posture.…”

Positional obstructive sleep apnea as a new interdisciplinary challenge

“…Spearman correlation analysis revealed There is a statistically significant negative correlation between allergic rhinitis score and POSA (Spearman coefficient of r = -0,40; p < 0,0001) as well as a positive correlation between the apnea-hypopnea index and body mass index (Pearson coefficient of r = 0,32; p < 0,05). The result from a comparative retrospective study of 30 POSA and 45 non-POSA patients by means of polysomnography and computed tomography demonstrate statistically significant differences (p < 0,05) between both groups in terms of the apneahypopnea index, lateral apnea-hypopnea index, soft palate length, cross-sectional palatopharyngeal area, and coronal diameter of the palatopharyngeal area at the narrowest glossopharyngeal part (13). Only the apnea-hypopnea index, lateral apneahypopnea index and soft palate length values are lower in POSA patients.…”

Upper airway morphology in adults with positional obstructive sleep apnea

“…However, only a few studies have compared craniofacial structures between POSA and NPOSA groups. Two studies have suggested that patients with POSA may have a smaller lower facial height, more backward positioned mandible, and shorter soft palatal length than patients with NPOSA [ 13 , 14 ]. However, Saigusa et al [ 14 ] found no significant difference in the anatomical balance of the upper airway between the POSA and NPOSA groups in their study.…”