Marie-Louise Walker-Engström

Centrum för klinisk forskning, Centrallasarettet Västerås

Titel: "Treatment effects with a mandibular advancement appliance and uvulopalatopharyngoplasty in obstructive sleep apnea"

Disputation: Torsdagen 8/5 2003 kl. 09.00, Robergsalen, ing 40, 4 tr., Akademiska Sjukhuset Uppsala.

Fakultetsopponent: Professor Elisabeth Hultcrantz, Öron-Näs-Hals avd., Universitetssjukhuset Linköping.

Dissertation for the degree of Doctor of Medical Science in Clinical Physiology presented at Uppsala University in 2003.

Abstract

Walker-Engström, M-L. 2003. Treatment effects with a mandibular advancement appliance and uvulopalatopharyngoplasty in obstructive sleep apnea. - randomised controlled trials- Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the faculty of Medicine 1240. 88pp. Uppsala. ISBN 91-554-5578-6.

Enthusiasm for uvulopalatopharyngoplasty (UPPP) in the treatment of mild-to-moderate obstructive sleep apnea syndrome (OSAS) has declined in recent years, partly because of a lower success rate over time and partly because of adverse effects. In more severe cases, the patients are generally treated with nasal continuous positive airway pressure (CPAP). However, many patients do not satisfactorily tolerate CPAP as a result of frequent side-effects. Consequently, there is a need for an alternative treatment. Reports on the beneficial effects of mandibular advancement appliances in the treatment of mild-to-moderate OSA exist in the form of short?term evaluations.

One of the aims of the present thesis was to compare treatment effects with a mandibular advancement appliance and UPPP in patients with OSA with follow-up after one and four years. Ninety-five male patients with confirmed mild-to-moderate OSA (apnea index, AI >5 and <25) were randomised to treatment with a dental appliance or UPPP. Sleep studies were performed before and one and four years after intervention. According to the criteria for normalisation (AI<5 and apnea hypopnea index, AHI<10), 78% of the patients in the dental appliance group and 51% of the patients in the UPPP group had normalised after one year (p<0.05). Still after four years of treatment, 63% of the patients in the dental appliance group and 33% of the patients in the UPPP group were normalised. The dental appliance group had a higher normalisation rate than the UPPP group, but the efficacy was partly invalidated by the compliance rate of 62%. Quality of life assessments in the dimensions of vitality, contentment and sleep improved in both groups at the one-year follow-up after treatment. There was no difference between the groups in terms of vitality and sleep. The UPPP group, however, reported a higher degree of contentment than the dental appliance group, even though the somnographic values were superior in the latter group.

Another aim was to conduct a randomised study to test the hypothesis that severe OSA patients will benefit from more pronounced mandibular advancement (MA) compared with a shorter advancement. Eighty-six males with severe OSA (AI>20) were randomly allocated to either 75% or 50% MA for a six-month treatment period. Treatment with a more pronounced mandibular advancement yielded a 20% higher normalisation rate than a shorter advancement. A mean normalisation rate of 45% was found for patients in this category with few side-effects, good patient satisfaction and a compliance of 92% after 6 months.

The overall conclusion is that dental appliance treatment is effective in patients with mild to moderate OSA and even for patients with severe OSA. The efficacy in terms of normalisation in patients with mild to moderate OSA was higher after the dental appliance treatment with a 50% degree of advancement than after the UPPP treatment. However, severe OSA patients might benefit from more pronounced advancement (75%) compared with a shorter degree of advancement (50%). QOL improved significantly after both dental appliance and UPPP treatment.

Key words: oral appliance, dental appliance, obstructive sleep apnea, UPPP, quality of life, somnography, randomised controlled trial, one-year follow-up, four-year follow-up, severe obstructive sleep apnea

Marie-Louise Walker-Engström, Centre of clinical research, Central hospital Västerås, Uppsala universitet, SE-72189 Västerås, Sweden.