03 June 2020

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Sinus floor elevation: intraoperative complications with two ultrasonic tecniques

Giulia Palandrani

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Tooth loss results in  bone remodeling and reduction in horizontal and vertical dimensions of the alveolar ridge. In the posterior upper jaw a sinus pneumatization can also occur, resulting in the impossibility to place implants.  In these cases the sinus floor elevation is required. This procedure has been widly validated and different tecniques have been described. The traditional technique consists in an antrostomy  performed drilling a bone window in lateral sinus wall and an elevation of the Schneiderian membrane   in order to insert grafting materials.
The most frequent intraoperative complication is Schneiderian membrane perforation , its prevalence rates  from 5  to 56%.with rotary instrumentation, and 4 to 31% with ultrasonic techniques.

Materials and Methods
 In this RCT 72 adult patients underwent unilateral sinus lift    , the aim of this study was to compare and to assess the prevalence of intraoperative complications using two different ultrasonic approaches in order to create lateral antrostomy  : an outlining of the bony window on the lateral wall of the sinus  ( group A) or an erosion of the cortical plate until the dark color of the sinus cavity appears under a thin layer of bone, before outlining the window  (group B). After the antrostomy   in both groups. membrane elevation was completed  with hand instruments.

Results
 This study report four perforations of the Schneiderian membrane:
- (11.1%) in group A (two occurred during membrane elevation with manual instruments) 
- zero perforations in group B (p<0.05).
Three out of four perforations were associated with the presence of Underwood’s septa (p < .05), which was encountered in 20 cases (27.8% prevalence; nine in group A [25%], 11 in group B [30.6%]) No evidence of vascular lacerations or profuse bleeding was registered in both groups and no other complications were registered. Shorter surgical time was recorded in group A (9.2 1 3.7 minutes) than in group B (13.3 1 2.4 minutes; p < .05). These findings are in accordance with data present in literature on ultrasonic lateral approach. A possible explanation could be related to the better visibility and less load application on the handpiece due to the easier perception of membrane proximity when using erosion technique. Furthermore, erosion technique could allow for more efficient cooling of the piezoelectric insert in proximity of the membrane, highly susceptible to thermal damages.

Conclusions
 The authors conclude that ultrasonic erosion of the lateral wall of the sinus is a more predictable technique than piezoelectric outlining of a bone window in preventing from accidental perforations  of Schneiderian membrane. The presence of Underwood’s septa seems not to increase risk of perforations  when using this technique.    

For additional Information: Intraoperative Complications During Sinus Floor Elevation with Lateral Approach: A Systematic Review.