The epidemiological data obtained in our study on cleft lip and palate (CLP) provide important insights into the distribution of this malformation within our patient population. The mean age of 11.6 years with a variability ranging from 3 months to 78 years reflects the diversity of the stages of diagnosis and management of CLP. This variability in the mean age at the time of seeking care is in accordance with the results reported by Sangwa et al. in Lubumbashi (DRC) reporting 11.8 years [12] and by Longombe and Tshimbila in Goma (DRC) finding 9.9 years [13]. The finding that almost half of our patients presented at the age of 5 years or younger highlights the importance of early detection of CLP. This is consistent with recommendations from other studies, which emphasize the positive impact of early intervention on both functionally and aesthetically [14]. On the other hand, the significant proportion (51%) of patients aged over 5 years at the time of consultation raises questions about the factors which could contribute to a late diagnosis. Previous studies have suggested that socioeconomic barriers, limited access to health care, or lack of awareness of the malformation could influence the timing of consultation [15–17]. Additionally, in African communities, the birth of a malformed baby is considered a tragic event due to the religious and mystical considerations surrounding it. Children who have a cleft lip and palate at birth are often hidden by their parents for fear of stigma and discrimination and may cause divorce [12, 18]. Understanding these factors is essential to implementing strategies to reduce the delay in making the diagnostic and improve access to care.
The present study highlights a significant predominance of the male sex among patients with CLP, with a sex ratio of 1.4 in favor of male. This observation raises relevant questions about gender differences in CLP prevalence. The predominance of the male sex in our cohort is consistent with previous findings reported by several Congolese studies [10, 12, 13, 19]. For example, a study conducted in Goma (DRC) revealed a male predominance of 59.2% in patients with cleft lip and palate [19]. Another study conducted in Lubumbashi (DRC) revealed a male/female ratio of 1.2:1 in patients with cleft lip and palate [12]. However, variations in sex distribution have been observed in other study populations [20–22]. These differences could be the result of genetic or environmental variations that merit further investigation. Genetic studies have suggested associations between certain genes involved in facial development and predisposition to CLP, but the exact understanding of the mechanisms underlying sexual predominance remains incomplete [23, 24].
The results of the present study highlight a prevalence of family history of cleft lip and palate (CLP) among our patients, with 72 cases representing 4.3% of the total sample. In the study by Sangwa et al. [12], the presence of family history was reported at 20.7%. This observation raises intriguing questions about the potential contribution of the genetic component in the development of some cases of CLP, and it is important to explore these findings in light of the work of other investigators. Previous studies have also reported associations between CLP and positive family history, thus supporting the idea of a genetic predisposition [10, 25]. These findings support the hypothesis that genetic factors may play a critical role in the pathogenesis of CLP. Extensive genetic investigations have identified several CLP-associated genes involved in embryonic facial development. Genetic variability may contribute to the diversity in CLP prevalence in families [26, 27]. However, it is essential to note that despite the presence of a family history, the majority of cases of CLP occur sporadically. This suggests a complex interaction between genetic and environmental factors in triggering this malformation [26]. Environmental exposures, such as nutritional factors, exposure to toxins, or other unknown factors, could also influence the risk of CLP, even in the absence of a genetic predisposition. A Chinese study reported a significant association between heavy metals and the occurrence of CLP [28].
In the present study, the identification of 25 cases (1.5%) of CLP associated with other visible malformations reinforces the idea that CLP may be part of more complex syndromes presenting a variety of anatomical abnormalities (Dixon et al., 2011; Leslie, 2017). The prevalence of these associations varies considerably depending on the populations studied, with rates reaching 21% [29, 30], highlighting the diversity of epidemiological contexts. These differences could be influenced by genetic factors specific to each population, variations in data collection methodologies, or differences in the diagnostic criteria used. Genetic studies have identified syndromes associating CLP with other congenital malformations, highlighting underlying genetic abnormalities that influence overall embryonic development [31]. Early recognition of these associations may have important implications for clinical management, particularly in terms of planning surgical interventions, medical monitoring, and assessment of overall prognosis.
As for the anatomical varieties of CLP, comparing our results with other studies, this study has similar trends regarding the predominance of cleft lips, followed by combinations of cleft lip, alveolar and palate. [12, 13, 20]. However, variations in specific percentages can be observed, highlighting the diversity in the anatomical presentation of CLP between different populations. The predominance of isolated cleft lip in our study is consistent with previous studies [12, 13, 20]. This observation suggests that cleft lips often represent the primary manifestation of the malformation. The high frequency of lip and alveolar clefts (15.7%) underlines the importance of the involvement of the lip and the alveolus in the pathogenesis of CLP. The identification of isolated cleft palates in 2.6% of patients in our study is in line with the generally lower prevalence of isolated cleft palates compared to cleft lips because they are hidden and do not attract parental attention or they simply do not want to talk about it as malformations are misinterpreted in Africa [13]. These results highlight the heterogeneity of clinical presentations of CLP and highlight the need for an individualized approach in clinical management. Complex associations between the lips, palates, and alveoli, such as cleft lip (15.7%) and cleft lip/palate (10.6%), are consistent with the expected anatomical variability in the CLP. These multiple associations reflect the diversity of abnormalities in embryonic facial development and require in-depth surgical and multidisciplinary management.
Regarding the location of CLP, the observation that the left side is more frequently affected, is consistent with similar findings reported in the literature [12, 13, 21, 32]. These findings could be related to specific embryonic mechanisms or environmental factors influencing the prevalence of left-sided CLP.
Regarding the distribution of complete and incomplete forms of CLP, our finding that complete forms predominate at the lips and palates, while incomplete forms dominate at the alveoli, is consistent with previous observations [12, 13, 21]. This distribution may be linked to differences in stages of embryonic development or to specific pathogenic mechanisms in these anatomical regions. However, variations in these trends have been noted in other studies, highlighting the complexity of CLP genetics and embryonic development. Genetic and environmental factors specific to each population could influence these differences, requiring further exploration.
Talking about the management of cleft lip and palate, more than 81.4% patients had cleft lip repaired according to the Straight on-line, Millard, and Mulliken techniques. In the present study, the Straight on-line technique was used for incomplete unilateral cleft lip repair, the Millard or Modified Millard technique was used to repair the complete unilateral cleft lip and the Mulliken technique for bilateral cleft repair. Studies elsewhere have described that the modified Millard technique is commonly used for cleft lip repair, particularly in the United States of America and Europe [33]. The Manchester and Mulliken techniques are best performed for bilateral labiaplasty. The advantages of the Mullikens procedure are lengthening of the columella with superior repair of the nostril [34]. A multicenter analysis carried out in Germany reported five most commonly used lip repair techniques from 37 participating centers. These were the Randall-Axhausen, Tennison, Pfeiffer, Delaire, Millard and Tennison-Randall techniques. The Millard (12/37 centers) and Tennison (14/37 centers) techniques were the most popular [35]. Gatti et al. [36] used the Tennisson-Randall and modified Millard techniques respectively to perform unilateral cleft lip surgery and the Mulliken technique was used for bilateral cleft lip.
Regarding palate repair, Cubitt et al. [37] revealed that palatoplasty is more performed in developed countries than developing countries. Sub-Saharan African countries have low rates of cleft palate repair. In this study, 20.0 and 2.6% of respectively CLP and CP patients had undergone palatoplasty by practicing Von Langenbeck and Bardach techniques. When performing bilateral palatoplasty, the Bardach technique is performed more commonly where a vomer flap is applied for reconstruction [35]. Gatti et al used the Bardach or Von Langenbeck technique from the age of 6 months to repair the palate [36]. The study by Akinmoladun et al. [38] showed that Millard's rotation and advancement technique was used for lip repair in 91.2% and 63.7% used Von Langenbeck technique for palatal repair. To date, systematic reviews of the published literature have revealed no consensus on which treatment provides the best patient outcome [39]. In most cases, the surgical approach is entirely based on the personal preference of the surgeon, and most surgical centers have their own technique of choice [40].
The results of this study must be interpreted taking into account certain limitations. First, this study does not include information on the long-term outcomes of patients who underwent CLP reconstructive surgery. Follow-up over a prolonged period would have made it possible to assess the results of surgical interventions, possible complications, and the impact on quality of life. Second, this study could be subject to selection bias, because it is based on cases of cleft lip and palate identified during awareness campaigns. Patients who participated in the campaigns may not be representative of the entire population with this malformation, as some individuals may not have had access to these awareness services.
Despite these limitations, this study has a number of notable strengths. First, the sample size of 1666 CLP cases represents a substantial sample size, providing an important database to describe the characteristics of this malformation. Additionally, this study provides an important perspective on the local population affected by CLP, which may have direct implications for public health policies and awareness interventions.