Sinus augmentation via transcrestal approach: a comparison between the balloon and osteotome technique in a cadaver study.

BACKGROUND: The transcrestal approach with osteotomes is a commonly applied and predictable technique for maxillary sinus floor elevation. However, Schneiderian membrane perforation is a common and often inevitable intraoperative complication. Recently, the use of balloons has been proposed to reduce the risk of sinus membrane perforation and to facilitate the surgical technique. The aim of this study was to determine membrane elevation height and perforation rate using the transcrestal balloon technique (B) and a conventional osteotome approach, as control (C).

METHODS: Ten fresh, completely edentulous cadaver heads (seven male and three female) were selected. In a split-mouth design, each sinus was randomly assigned to either the experimental or the control technique. Pre-surgical planning was aided by cone-beam computed tomography. During the procedure, an endoscope was used to monitor the elevation procedure and the occurrence of sinus perforation. The elevation continued until either 15 mm (measured from the alveolar crest) was reached or a perforation occurred. The residual ridge and the elevated membrane height were measured and compared with the paired Student's t-test. Presence of sinus perforation was recorded at three cutoff points: 10, 12, and 15 mm.

RESULTS: The mean age of the specimens was 77.7 ± 14.2 years (range 49-92). The mean initial, final, and elevated sinus membrane height for the B group was 5.3 ± 1.9, 13.7 ± 1.9, and 8.3 ± 3.1 mm, whereas the correspondent values for the C group were 5.1 ± 2.1, 13.2 ± 2.8, and 8.1 ± 3.1 mm. The incidence of sinus perforation, using 10, 12, and 15 mm as end points was 0%, 22.2%, and 44.4% in the B group, whereas in the C group the respective values were 10.0%, 20.0%, and 50.0%. No statistically significant differences were found between the two groups for all the above-mentioned variables. In addition, mean residual ridge height was not significantly different between the non-perforation and perforation sites in the B group (5.2 ± 2.2 and 5.5 ± 1.7 mm) and in the C group (5.2 ± 2.5 and 5.0 ± 2.0 mm). Three cadavers had perforations in both sinuses, accounting for 66.6% of total number of perforations.

CONCLUSIONS: Based on the findings of this study, the balloon and the conventional osteotome approach are comparable in terms of perforation rate as it relates to the elevation height. Also, the amount of residual alveolar bone was not related to the incidence of perforation and the height of sinus elevation.