Thikriat Al-Jewair BDS, MSc, FRCD (C)
Maxillomandibular advancement (MMA) is the most successful surgical therapy, as an alternative to lifelong ventilation therapy, in the treatment of obstructive sleep apnea syndrome (OSAS).
In adults with OSAS, is MMA compared to conventional continuous positive airway pressure (CPAP) ventilation therapy more efficient in reducing objective and subjective OSAS signs and symptoms?
The authors searched only one database for articles published in English between 1985 and January 2010. They also screened reference lists of identified articles. The authors chose to include articles with patients 20 to 65 years old who were diagnosed with OSAS by polysomnography (PSG) and who received MMA as their main treatment with or without adjunctive surgery. The authors excluded patients who had craniofacial syndromes, acromegaly, or temporomandibular joint disorders. The authors’ primary outcomes of interest were those obtained by PSG; however, they also summarized other findings such as the Epworth Sleepiness Scale (ESS) scores, patients’ esthetic concerns assessed by questionnaires, patients’ perceptions, and objective findings such as reaction time and imaging results when reported. The authors used the Oxford Centre of Evidence-Based Medicine system to assess the quality of the included studies on a scale from 1 to 4 with 1 being the highest quality. They did not perform a meta-analysis.
A total of 39 studies (N=1,213) were included and divided into two groups: group A, studies describing pre- and post-operative PSG of patients who received MMA (n=28) (with additional surgical interventions listed if applicable); and group B, studies that did not describe PSG findings but reported other outcomes such as long-term skeletal stability, post-operative endoscopic findings, soft tissue changes, or the need for bone grafting. Most studies in group A were of poor quality (level 4) except five cohort studies (level 2b) and one RCT (level 1b). All studies in group B were level 4. The success rates (measured by improvement of apnea/hypopnea, apnea, or respiratory disturbance indices, or arterial oxygen hemoglobin desaturation levels) ranged between 65 to 100 percent with the sample sizes between 3 and 175 patients. The mean duration of follow up was 6 months, although the minimum was 6 weeks after surgery. All studies showed that MMA is effective in treating OSAS.
The review suggested that MMA is an effective treatment of OSAS. Long-term follow-up studies are lacking.
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Importance and Context:
CPAP is considered the gold standard for treating OSAS; however, some patients do not comply with CPAP therapy, which requires a lifetime commitment. Some recent studies [1-2] have shown that MMA produces comparable results to CPAP, indicating MMA may be a viable option for some patients. Strong evidence on the effectiveness, success rates, and long-term stability of MMA in OSAS patients is needed.
Strengths and Weaknesses of the Systematic Review:
There are several significant limitations in this poorly conducted systematic review. The authors limited the search to only one database, did not search the grey literature and only considered articles published in English. The potential for publication bias was not assessed. Because the authors did not specify a minimum sample size in the inclusion criteria, the review included studies with as few as three subjects. The authors included low-quality, high bias studies (e.g., case series) in addition to any outcome measures, regardless of pertinence. The designs of the cohort studies were not specified. Also, they did not report the number of reviewers who assessed the quality of included studies. As appropriate, the authors did not perform a meta-analysis because of the varied nature of the evidence.
Strengths and Weaknesses of the Evidence:
Most of the studies were of poor quality except for one RCT (level 1b) with 12 months’ follow-up comparing patients treated with CPAP versus MMA and five cohort studies (level 2b). The RCT did not find significant differences between the groups. Twenty-eight studies used pre-and postoperative PSG as an outcome measure, but the definition of success rate as well as the follow-up periods varied among the studies. In 21 studies (75 percent), the results of MMA might have been confounded due to patients having adjunctive surgical procedures performed before, during, or after the MMA. Several studies assessed subjective variables using non-validated questionnaires.
Implications for Dental Practice:
This systematic review suggested that MMA is an effective treatment for OSAS; however, the generally poor quality and high heterogeneity of the evidence limits the certainty of this conclusion. Based on this systematic review and current literature, it is recommended that stronger levels of evidence be produced using study designs of higher quality, developing standard definitions of success rates, following treated patients long-term and assessing complications of the treatment modalities. Future studies should assess the degree of OSAS to determine if any given therapy is better suited for a specific target OSAS group. References: 1. Varghese R, Adams NG, Slocumb NL, et al. Maxillomandibular advancement in the management of obstructive sleep apnea. Int J Otolaryngol 2012; Volume 2012: Article ID 373025, 8 pages. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3299305/ Accessed February 28, 2014. 2. Boyd SB, Walters AS, Song Y, Wang L. Comparative effectiveness of maxillomandibular advancement and uvulopalatopharyngoplasty for the treatment of moderate to severe obstructive sleep apnea. J Oral Maxillofac Surg 2013;71(4):743-51.