The placement of dental implants in the maxillary posterior region often involves maxillary sinus floor elevation (SFE) to augment insufficient alveolar bone. However, one of the most common complications of this procedure is the perforation of the Schneiderian membrane, with reported prevalence ranging from 8% to 32%. Factors such as sinus septa, low residual bone height, and smoking increase the risk of membrane perforation. While there are conflicting reports on the impact of membrane perforation on implant survival rates, it is believed to be associated with complications such as sinusitis. Various methods have been developed to repair membrane perforations, but most studies focus on repair procedures via a lateral approach for SFE.
To address the issue of membrane perforation during SFE, a crestal approach can be used instead of a lateral approach. This approach minimizes patient discomfort by avoiding the need for a second operation site. Additionally, studies have shown that the incidence of maxillary sinusitis is lower with the crestal approach compared to the lateral approach. However, membrane perforation remains a risk factor for postoperative sinusitis, which can negatively impact implant survival rates.
To minimize complications during SFE, it is important to identify and diagnose any anatomical structures or pathological findings before surgery. Cooperation with an otorhinolaryngologist is recommended in cases of asymptomatic maxillary sinus lesions, chronic maxillary sinusitis, and nasal septum deviations. Evaluation of the vertical resorption of alveolar bone and the position of the posterior superior alveolar artery can help prevent arterial bleeding. Thin or thick sinus lateral walls increase the risk of membrane perforation, while the presence of sinus septums can also increase this risk. The condition of the maxillary ostium, as well as any history of sinus-related surgery or maxillary sinusitis, should be evaluated to assess the risk of postoperative complications.
In Case 1, a crestal sinus lift using the Crestal Approach Sinus Kit (CAS Kit) was successfully performed on a patient with a missing upper left first molar. The procedure involved lifting the sinus membrane and filling the sinus cavity with bone graft material before placing an implant. The use of a hydraulic lifter with saline solution helped safely raise the membrane without perforation. The patient achieved a successful vertical sinus lift with minimal invasiveness.
In Case 2, a patient with a congenitally missing upper right back molar underwent a sinus lift in conjunction with the extraction of a wisdom tooth. The sinus membrane was lifted using a 3.3 mm drill, and the sinus cavity was grafted with a mixture of cortico-cancellous bone. An implant was then placed, and the patient experienced successful healing and restoration.
In conclusion, perforation of the Schneiderian membrane is a common complication during maxillary sinus floor elevation for dental implant placement. While the crestal approach offers advantages in terms of patient comfort, membrane perforation remains a risk factor for postoperative sinusitis and implant failure. Careful evaluation and diagnosis before surgery, as well as proper techniques and tools, can help minimize complications and achieve successful outcomes.