Monospermy occurs in the process of normal fertilization where a single sperm fuses with the egg, resulting in the formation of a diploid zygote. During the process of fertilization, the sperm must penetrate the zona pellucida (ZP), the outer layer of the egg, to reach the egg’s plasma membrane. Once a sperm binds to the ZP, it undergoes an acrosomal reaction, which involves the release of enzymes from the sperm’s acrosome that help it to penetrate the ZP. Ovastacin is one of the enzymes that is involved in breaking down the ZP. Studies have shown that ovastacin is necessary for the breakdown of the ZP and for successful fertilization to occur. However, the activity of ovastacin is tightly regulated to ensure that only one sperm can fertilize the egg. One way in which ovastacin helps to prevent polyspermy (the fertilization of an egg by more than one sperm) is by rapidly degrading the ZP after a sperm has penetrated it. This makes it difficult for additional sperm to penetrate the ZP and fertilize the egg. Ovastacin is also thought to play a role in the block to polyspermy, a mechanism that prevents additional sperm from fusing with the egg’s plasma membrane after fertilization has occurred. In summary, the role of ovastacin in monospermic fertilization is to help ensure that only one sperm can fertilize the egg, while preventing polyspermy and ensuring successful fertilization.

Background and Objectives: Endoscopic prelacrimal recess approach (PLRA) was introduced to treat maxillary sinus inverted papilloma (IP) without sacrificing the inferior turbinate and nasolacrimal duct. This study aimed to compare surgical outcomes of prelacrimal recess approach with the conventional Caldwell-Luc approach (CLA) to remove IP of maxillary sinus and to evaluate the usefulness of the PLRA.Subjects and Method We retrospectively reviewed medical records of 51 patients who were treated in our institution for IP of nasal cavity and sinuses between March 2010 and June 2019. Twenty patients had maxillary sinus IP. Sixteen patients underwent endoscopic sinus surgery combined with either CLA (n=8) or PLRA (n=8). Demographic data, surgical technique, site of IP origin, intra- and postoperative complications, duration of follow-up, recurrence rate and pathologic diagnosis were reviewed. Results: IP was the pathologic diagnosis for all 16 cases. Gross total removal was achieved in all cases. The mean follow-up period was 20.1 months in CLA group and 12.5 months in PLRA group. There was one case of massive bleeding during operation requiring transfusion and postoperative ICU care in CLA group. On postoperative follow-up, two patients from the CLA group had recurrence during the follow-up period. One patient had numbness around the gingival area, another patient had transient wound dehiscence, and another had persistent oro-antral fistula. In PLRA group, one patient had periorbital swelling after blowing nose; otherwise, no other patient from the PLRA group developed subjective complaints after surgery. Conclusion Endoscopic prelacrimal recess approach showed lower complication rates and recurrence rates compared to CLA. PLRA is a safe and effective method for the excision of primary maxillary sinus IP.