TABLE IV. C. 3.

Evidence for craniofacial anatomy as a contributor to OSA

Study	Year	LOE	Study design	Study groups	Clinical endpoints	Conclusions
Jamieson et al.216	1986	3b	Case–control study	Adult OSA patients (n = 155) and non-OSA controls (n = 17)	Lateral cephalometry	OSA patients had greater retroposition of the mandible and a more acute cranial base angle.
Hochban and Brandenburg217	1994	3b	Case–control study	Adult OSA patients (n = 403) and non-OSA controls (n = 88)	Lateral cephalometry	OSA patients had longer facial type, retroposition of the mandible, more dorsocaudally positioned hyoid bone, and an anteroposterior narrowing of the posterior airway space.
Frohberg et al.218	1995	3b	Case–control study	Adult OSA subjects (n = 30) and adult chronic snorers (n = 20)	Lateral cephalometry	OSA group had retroposition of maxilla and lower positions hyoid.
Lowe et al.219	1995	3b	Case–control study	Adult OSA subjects (n = 80) and non-OSA controls (n = 25)	Cephalometric measurements obtained from CT	OSA subjects have higher upper and lower facial heights, elongated maxillary and mandibular teeth, and proclined lower incisors.
Battagel et al.220	1996	3b	Case–control study	Adult OSA patients (n = 35) and healthy non-OSA controls (n = 24)	Lateral cephalometry	OSA patients had shorter cranial base length, shorter mandiblular body length, enlarged soft palate.
Tsai et al.221	2007	3b	Case–control study	Asian adult non-obese severe OSA patients (n = 46) and non-obese, snoring controls (n = 36)	Lateral cephalometry	Severe OSA patients had increased soft palate length and lower positioned hyoid bone compared to snorers.
Riha et al.222	2005	3b	Case–control study	Adult patients with OSA (n = 22) and non-OSA sibling controls (n = 22)	Lateral cephalometry	OSA patients had shorter mandibular body length and lower positioned hyoid compared to non-OSA siblings.
Johal et al.231	2007	3b	Case–control study	Adult OSA patients referred for oral appliance (n = 78) and gender matched healthy non-OSA controls (n = 78)	Lateral cephalometry	OSA patients the following differences compared to non-OSA controls: low set hyoid, retroposition of the mandible (SNB angle), increased soft palate length, thickness, and area.
Gungor et al.225	2013	3b	Case–control study	16 Turkish adults with OSA and 16 Turkish non-OSA controls	Lateral cephalometry	OSA subjects had shorter midface length, protrusion of upper incisors, and lower positioned hyoid bone.
Banhiran et al.226	2013	3b	Case–control study	Adult OSA patients divided into mild (n = 43) and moderate/severe (n = 98) categories compared to non-OSA controls (n = 47)	Lateral cephalometry	Moderate/severe apneics had inferiorly positioned hyoid, shorter anterior cranial base angle, and longer soft palate compared to controls. There were no statistically significant differences between mild OSA patients and non-OSA controls.
Costa et al.227	2013	4	Case series	Portuguese Adult OSA patients (n = 171)	Cephalometric measurements stratified by BMI	Caudally positioned hyoid, rotated mandible, and decreased hypopharyngeal airway caliber were associated with increasing AHI severity.
Sakat et al.228	2016	3b	Case–control study	Japanese adult severe OSA patients (n = 30) and BMI matched non-OSA controls (n = 10)	Craniofacial measurements on sagittal CT versus OSA	Retroposition of maxilla (SNA angle), retroposition of mandible (SNB angle), inferiorly positioned hyoid, shorter mandibular length were associated with OSA.
Neelapu et al.229	2017	3a	Systematic review and meta-analysis	Adult OSA patients and healthy non-OSA controls (n = 26 articles)	Lateral cephalometry	Significant weighted mean difference with insignificant heterogeneity was found for the following parameters between OSA patients and non-OSA controls: greater anterior lower facial height, lower position of hyoid bone, and decreased pharyngeal airway space. Significant weighted mean difference with significant heterogeneity was found for the following parameters between OSA patients and non-OSA controls: shorter cranial base and angle, decreased mandible, increased mandible rotation, decreased maxillary length, increased tongue area, increased soft palate area, and increased upper airway length.
Chi et al.224	2011	3b	Case–control study	Adult OSA patients(n = 55) and healthy non-OSA controls matched for age, sex, and race (n = 55)	Cephalometry based on MRI	Significant mean differences between OSA patients and non-OSA controls: Inferiorly and posteriorly displaced hyoid is associated with OSA.
Seto et al.230	2001	3b	Case–control study	Adult OSA patients (n = 29) and non-OSA controls (n = 21)	Lateral cephalometry, maxillary width, and height on dental exam	OSA patients had shorter mandibular body length and lower positioned hyoid compared to non-OSA patients. On maxillary width, OSA patients showed decreased inter-molar widths and increased palatal index.
Johal et al.223	2007	3b	Case–control study	Adult OSA patients referred for oral appliance (n = 78) and gender matched healthy non-OSA controls (n = 78)	Lateral cephalometry	OSA patients had the following differences compared to non-OSA controls: low set hyoid, retroposition of the mandible (SNB angle), increased soft palate length, thickness, and area.
Kuzucu et al.232	2020	4	Case series	89 Adult OSA subjects	Craniofacial measurements on CT	Narrower interpterygoid distance and smaller interpetrygoid to velopharyngeal length ratio was associated with increasing AHI.
Lam et al.236	2005	3b	Case–control study	Asian adults (n = 164) and White adults (n = 75)	Craniofacial measurements on physical exam obtained with patient sitting upright with head in neutral position	OSA subjects had; larger thyromental angle, neck circumference, BMI, and Mallampati scores.
Ferguson et al.238	1995	4	Case series	Adult OSA patients divided into three groups based on neck circumference (n = 161)	Lateral cephalometry	Larger neck circumference apneics had lower hyoid bone positions, smaller neck circumference patients had smaller maxillary and mandibular lengths.
Tangugsorn et al.239	2000	3b	Case–control study	Obese OSA patients (n = 57), non-obese OSA patients (n = 48), and healthy non-OSA controls (n = 36)	Lateral cephalometry	Significant differences observed between OSA patients and non-OSA controls for the following parameters: inferiorly positioned hyoid, shorter cranial base, increased gonial angle, increased lower anterior facial height, decreased posterior facial height, large tongue, and large soft palate associated with OSA compared to non-OSA controls. Significant differences observed between non-obese and obese OSA patients for the following parameters: shorter mandibles, greater posteriorly displaced and rotated mandibles, greater anterior facial height, decreased posterior facial height.
Paoli et al.240	2001	3b	Case–control study	Obese adult OSA patients (n = 46) and non-obese adult OSA patients (n = 39)	Lateral cephalometry versus obesity	Retroposition of mandible (SNB angle), shorter cranial base, shorter mandibular ramus in non-obese OSA patients versus obese OSA patients.
Yu et al.241	2002	3b	Case–control study	Asian adult obese n = (33) and non-obese OSA patients (n = 29) and non-obese, non-OSA snoring patients (n = 13)	Lateral cephalometry	OSA patients have longer soft palates and lower hyoid position compared to snorers.
Lee et al.106	2010	3b	Case–control study	Caucasian adult OSA patients (n = 74) and Chinese adult OSA patients (n = 76)	Lateral cephalometry	Chinese OSA patients had shorter cranial base angle, shorter maxillary length, and shorter mandibular bodies compared to Caucasians. Chinese OSA patients had greater severity of OSA and lower BMI compared to Caucasians.
Xu et al.242	2020	3b	Case–control study	Icelandic adults (n = 108) and Chinese adults (n = 57) with OSA defined by ODI > 10 matched for age, gender, and ODI	Craniofacial dimensions as measured on MRI	Chinese subjects had bigger ANB angle, shorter mandibular corpus length, longer mandibular ramus length, and a wider and shallower maxilla.
Cakirer et al.244	2000	3b	Case–control study	Caucasian adults (n = 364) and African American adults (n = 165) and BMI <32	Cranial and facial indices measured using calipers	Caucasians with AHI > 5 had lower cranial and facial indices compared to those with AHI <5 while African Americans had similar cranial and facial indices between the same groups.