Is the Magnitude of Maxillomandibular Advancement Correlated with Long Term Changes in the Apnea-Hypopnea Index in Patients with Obstructive Sleep Apnea?

Statement of the Problem: Several studies indicate that maxillomandibular advancement surgery (MMA) is a clinically effective therapy for patients with obstructive sleep apnea (OSA) as measured by changes in the apnea-hypopnea index (AHI).  Some surgeons have advocated advancing the mandible at least 10 mm to effectively treat OSA, but currently it is unclear if there is a relationship between the magnitude of maxillomandibular advancement and long term changes in the AHI.  The purpose of this study was to determine if the magnitude of maxillomandibular advancement is correlated with long term changes in the AHI in patients with OSA. 

 Materials and Methods:  The investigators conducted a prospective long term cohort study composed of patients with moderate to severe OSA (baseline AHI >15) who underwent MMA for treatment of OSA at Vanderbilt University Medical Center. The primary outcome variable was the long term change in the AHI as measured by polysomnography (PSG) performed preoperatively and postoperatively greater than 3 years after surgery (mean follow-up 7.8 ± 2.5 years). The predictor variable was the magnitude of surgical advancement of the maxilla (A point) and mandible (B point), as measured from cephalometric radiographs taken preoperatively and postoperatively at the time of the long term PSG.

Methods of Data Analysis:  Descriptive and bivariate statistics were computed.  Spearman rank correlation coefficients were calculated to assess the association between changes in the AHI and the magnitude of maxillary and mandibular advancement.  Subgroup analysis was also performed after stratifying patients by magnitude of mandibular advancement and included: ≥ 10mm and <10mm.  For all analyses, a p-value of <0.05 was considered statistically significant.

Results: The study group was composed of 20 patients, who were primarily middle age (mean age, 47.6 ± 7.8 years), obese (mean baseline BMI, 28.1 ± 2.8) males (80%) with severe OSA (mean baseline AHI, 51.9 ± 22.3).  Surgical treatment resulted in a significant long term decrease in the AHI (51.9 ± 22.3 to 8.5 ± 10.9, P < 0.0001; Δ AHI = -43.3 ± 25.0).  The long term mean maxillary and mandibular advancements were 6.6 ± 2.3mm (range, 1.8-11.0) and 9.2 ± 2.9mm (range, 3.0-17.0) respectively. No strong association was found between changes in the AHI and the magnitude of advancement of the maxilla (r = .37; P = .111) or mandible (r = .32; P = 0.116).  However, patients with ≥10mm of mandibular advancement (n=8) had larger long term decreases in the AHI than those who had <10 mm of advancement (n=12) (≥ 10mm, Δ AHI = -53.1 ± 27.7 vs. < 10mm, Δ AHI = -36.8 ± 23.0).  This level of difference between the groups is clinically significant but did not meet the level of statistical significance (P= 0.1908). 

Conclusions:  The results of this study indicate that MMA produces significant long term decreases in the AHI over a relatively large range of maxillary and mandibular advancements.  No statistically significant correlation was found between the magnitude of maxillomandibular advancement and the long term change in the AHI, but mandibular movements of ≥10 mm on average produced the largest decreases in the AHI. 

 

Support:  This investigation was supported in part by a Research Support Grant Award from the Oral and Maxillofacial Surgery Foundation and in part by CTSA award No.UL1TR000445 from the National Center for Advancing Translational Sciences.  

 

References

Hsieh Y-J, Liao Y-F.  Effects of maxillomandibular advancement on the upper airway and surrounding structures in patients with obstructive sleep apnea: a systematic review.  Br J Oral Maxillofac Surg 2012; (DOI 10.1016/j.bjoms.2012.11.010).

Holty J-E, Guilleminault C.  Maxillomandibular advancement for the treatment of obstructive sleep apnea: a systematic review and meta-analysis.  Sleep Medicine Reviews 2010; 14: 287-297.