Results
Figure 1 shows the PRISMA flow diagram for studies selection. A total of
nine retrospective observational studies and one prospective
observational study were included. There were nine studies from North
America and one study from Southeast Asia. Results of the methodological
quality as assessed with Murad’s tool are shown in Table 2.
The studies included a total of 1836 patients, with 1369 (74.6%) males
and 467 (25.4%) females. One study (6) did not provide information on
the method of diagnosis of OSA. All the other studies used
polysomnography to confirm a diagnosis of OSA. Table 3 shows the
individual study characteristics and main outcomes.
Most patients in the included studies fell under the category of
moderate to severe OSA as indicated by the reported mean or average
Apnoea-Hypopnoea Index (AHI) or Respiratory Disturbance Index (RDI). Two
studies did not assess the severity of OSA among their participants (6,
7).
The majority of studies that reported participants’ average Body Mass
Index (BMI) were either in the overweight or obese category apart from
Pang et al (8) which reported a mean BMI of 24.6. However, it is worth
noting that this study was conducted in Singapore and the World Health
Organisation (WHO) has recognised that a BMI ≥ 23kg/m2among the Asian population indicates an increased health risk similar to
that of BMI ≥ 25kg/m2 in other populations (9). Two
studies did not have information on BMI (6, 10).
We evaluated the procedures reported; One study did not specify the
exact number of each surgery performed and was excluded from this
calculation (7). Of the 1741 surgeries performed, there were 268
(15.4%) nasal surgeries, 738 (42.4%) palatopharyngeal surgeries and
735 (42.2%) combined nasal and palatopharyngeal surgeries (including
concurrent tongue surgery). Nasal surgeries were either a septoplasty or
procedures to turbinates such as submucous diathermy/turbinoplasty or
both a septoplasty and turbinate surgery. All palatopharyngeal surgeries
included at least uvulopalatopharyngoplasty with various additional
procedures such as expansion sphincteroplasty, anterior palatoplasty or
tongue surgery however most studies did not provide the numbers of the
additional procedures.