Changes in the Schniderian membranes following sinus augmentation procedure are associated with baseline membrane’s thickness

Objectives: Maxillary sinus augmentation (MSA) techniques are predictable procedures aiming to increase the amount of bone available for implant placement in the posterior maxilla. These techniques have a potential risk of compromising the sinus physiology via changes to the muco-ciliary system of the Schneiderian membrane. Thus, the aim of the present study was to measure the Schneiderian membrane's dimensional changes following MSA via lateral approach and to examine the variables affecting the changes in the membrane's thickness.
Methods: Sixty-six sinuses corresponding to 50 patients (15 males and 35 females) which underwent lateral wall MSA (34 unilateral and 16 bilateral) were retrospectively evaluated. The Schneiderian membrane thickness (SMT) was measured on cross sectional computed tomography images which was performed prior to and 6-11 months post MSA. t-test for paired observations was used to compare between baseline and post-operative SMT. Pearson correlation test was used to analyze correlations between graft height and changes in the SMT.
Results: The mean age of these patients was 53±4 years . A total of 132 CBCTs were analyzed [pre-operative (n=66) and postoperative (n=66)]. The mean thickness of the Schneiderian membrane before the procedure was 2.61±3.61 mm while the mean thickness of the membrane after the procedure was 2.94± 3.51.
Thin membranes (<1.56 mm) gained thickness (mean 2.21±2.34 mm, ranges 0.19-10.1 mm) while thicker membrane (≥1.56 mm) lost 1.46±3.96 mm width (ranging from 0.35 to 9.31 mm). These difference between the groups were statistically significant (p<0.0001). No correlation was found between the graft height and changes in the SMT.
Conclusions: lateral wall MSA seems to affect the SMT. These changes are associated with the pre-operative thickness of the membrane.