## 3 Discussion  
The approach proposed in this study involves a modified surgical approach from what is generally utilized to manage perforations. However, this method is valuable and its application in clinical management of perforations results in minimal postoperative complications with no loss of bone graft placed at the site. Although not initially planned, the perforations were an incidental occurrence during surgery. The proposed procedure was employed to manage the large perforations, and such became a novel approach to circumferential large perforations during the procedure. The large perforations are generally challenging from a surgical management perspective. The proposed approach allows for continuation of treatment as planned without aborting the procedure due to large perforation. The access section of the sinus window displayed complete bony coverage notable with sufficient complete soft tissue coverage. The mechanism of soft tissue covering in the widely perforated area is not clearly understood. However, we hypothesize reasons that could explain the success of this procedure. First, the regenerative potential of the Schneiderian membrane is excellent at the site of surgical injury [32; 36]. Second, as in the extraction socket, the bone graft substitute is mixed with the blood clot and stabilized. Blood supply to the bone graft is from a torn Schneiderian membrane and a buccal flap through an open lateral window. The blood clotting of the exposed bone graft substitute prevents additional leakage of the bone graft substitute. In particular, in two cases, the MSA performed simultaneously with the open lateral window technique and the conventional technique could be unintentionally compared. There was no difference in the clinical and radiological results of these two procedures. In particular, the bone volume change was not as remarkable as expected. In the CBCT scan, the exposed portion of the sinus bone graft was covered with soft tissue after surgery. The thickness of Schneiderian membrane remained unchanged for 6-12 months postoperatively. In patients with unrepairable perforation of the Schneiderian membrane, the lateral sinus floor elevation without repair of perforated Schneiderian membrane showed an unexpected healing process despite many risk factors. All the implants installed in the MSA were osseointegrated and continue to function well without failure. Ultimately, the proposed modification to MSA with large perforations is challenging and involves risks. It is an alternative treatment option that can be utilized for MSA targeting the Schneiderian membrane with a large perforation that is difficult to repair. Within the cases presented, implants placed simultaneously can be viewed as a challenge. This especially becomes critical considering that the implants placed with or without the primary stability are at a higher risk of being displayed into the sinus. The authors recommend circumventing the risk by employing implants that are tissue level as opposed to bone level with a wider collar. The combination acts like a plug at the osteotomy site and prevents any further apical displacement. The limitations of the proposed approach are encased by the fact that this case report is a preliminary documentation with a limited number of patients treated. Additionally, the patients that underwent this procedure had a non-complex medical history, primary ASAI or ASAII category. Medical conditions such as diabetes have been clinically documented to affect quality and time of healing. Conditions such as osteoporosis or bisphosphonate therapy can impact the overall quality and quantity of regenerated bone. The impact of these medical conditions has not been evaluated in the context of the proposed technique. An extensive discussion on the quality and long prognosis of this procedure cannot be carried out due to the limited sample size and follow up time documented currently.