Clinical and radiographic outcomes of reentry lateral sinus floor elevation after a complete membrane perforation

Background: Although small perforation of the maxillary sinus schneiderian membrane is a well-documented complication during lateral sinus floor elevation (LSFE), complete perforations larger than 10 mm often result in discontinuation of surgery. Reports on reentry LSFE and its long-term outcomes are sparse. Purpose: To evaluate the long-term outcomes of reentry LSFE following complete membrane perforation to elucidate the technical details of the reentry procedure. Materials and methods: We assessed the medical records of all patients receiving LSFE from 2008 to 2017 in the Department of Oral Implantology, Peking University Hospital of Stomatology. Twenty-two patients receiving reentry LSFE after complete membrane perforation were enrolled. Data were recorded using cone beam computer tomography: including the residual bone height, membrane thickness of the sinus prior to surgery (MT1), and before reentry (MT2), and height of the bone graft during the reentry procedure (HBG). Cumulative survival rate of implants (CSR), marginal bone loss (MBL), and subsequent complications were also recorded. Results: From 2008 to 2017, 2023 consecutive patients (2262 sinuses) who underwent LSFE were screened. Complete membrane perforation occurred in 28 patients and resulted in discontinuation of surgery (1.2%). Twenty two patients were enrolled and received reentry LSFE within 3-6 months. Two patients undergoing the reentry procedure were suspended due to excessive membrane perforation, while the other 20 finished reentry sinus bone graft. In the reentry procedure, the HBG was 9.73 +/- 2.67 mm with 34 implant placements. The MT1 and MT(2)were 1.03 +/- 0.43 and 1.91 +/- 1.45 mm, respectively, showing a statistically significant difference (P< .05). After a follow-up of 2-10 years, CSR was 97.1%, and MBL was 0.64 +/- 0.50 mm. Conclusions: The long-term outcome of reentry LSFE is predictable and reentry LSFE offers a reliable alternative following complete membrane perforation. However, the procedure is relatively sensitive and should be performed by experienced surgeons.