In conclusion, and within the limits of its retrospective nature, our study implies that in cases of intraoperative perforation of the Schneiderian membrane, a consequent surgical assessment and treatment might avoid complications regarding graft stability and implant survival. Two-stage procedures might be appropriate if primary stability does not seem to be achievable. Augmentation of the sinus floor might be possible even in cases of perforation. A negative impact on the bone graft itself or on remodeling processes in follow-up could not have been shown, but prospective long-term studies should be performed to deliver reliable data on the impact of membrane perforation on graft stability and implant survival.