Study objectives: The effect of therapy using a cervicomandibular support collar (CMSC) to manage obstructive sleep apnea (OSA) was compared with standard therapy, nasal continuous positive airway pressure (nCPAP).
Design: Subjects received treatment with CMSC or nCPAP each for 1 month in random order. The study was analyzed on an intention-to-treat basis.
Setting: Tom McKendrick Sleep Laboratory, Dunedin Hospital.
Participants: Ten adult subjects with mild-to-moderate OSA (apnea-hypopnea index [AHI], 24 +/- 13/h slept [mean +/- SD]) completed the study.
Interventions: The CMSC was designed to prevent mandibular movement and hold the head in slight extension, thus preventing the postural changes that might contribute to OSA. Positioning of the CMSC was confirmed by an externally applied cervical range of motion (CROM) instrument and by cephalometry. Subjects were carefully instructed in the use of each device and completed a symptom diary. After 1 month, subjects underwent polysomnography with each of the allocated devices in situ, and symptom questionnaires were administered.
Measurements and results: Treatment success (AHI </= 10/h slept) with CMSC was achieved in only 2 of 10 subjects, partial success (AHI > 10/h to </= 15/h slept) was achieved in 2 subjects, and in 6 of 10 subjects there was no benefit. In contrast, treatment success was achieved in 7 of 10 subjects receiving nCPAP. Mean AHI was 29.4 +/- 13.4/h at baseline, 26.9 +/- 17.2/h slept with CMSC, and 9.9 +/- 8.0/h slept with nCPAP (p = 0.001). No significant differences in sleep architecture or sleep efficiency were achieved using nCPAP compared to CMSC. The efficacy of the CMSC in maintaining the desired head position was confirmed by cephalometry and the CROM instrument.
Conclusions: Our results, although negative, provide important evidence that control of head and neck posture, perhaps adopted as a second-line treatment, is not helpful in the management of OSA. It appears that other anatomic and physiologic factors have a dynamic overriding influence on upper airway closure compared to simple skeletal relationships.