The research mainly focused on surgeries and fistula-related risk determinants. The available evidence was low level and of poor quality. No consistent pattern between fistula occurrence and any of the risk determinants could be detected. Reported fistula rates did not differ significantly when comparing older studies with more recent studies or when high-quality studies were compared with low-quality studies.

Almost one quarter of the patients, developed fistula, and fistula incidence declined after 2009. The higher fistula rates were determined by cleft severity, time period of treatment, type of surgery, and surgeon's experience.

The proposed protocol has the potential to enhance the quality of patient care by ensuring that multiple patient-related aspects are consistently reported. It may also facilitate future multicenter research, which could contribute to the reduction of fistula occurrence in cleft lip and palate patients.