Cleft lip and palate (CLP) is the most common craniofacial malformation, affecting up to 1 in 700 births throughout the world (Dixon et al., 2011). The repair process is complex and involves multiple procedures from birth to adulthood. It typically begins with the primary treatment, which is generally performed during the first 2 years of life, and aims to correct anatomical changes, and thus ensure an optimal morphological and functional outcome, thereby enhancing these children’s quality of life.

In recent decades, numerous studies have been dedicated to investigating the factors that influence craniofacial growth in children with CLP (Ross et al., 1987). One challenging aspect of treating CLP patients is dealing with maxillary hypoplasia, which often becomes an unavoidable consequence. Maxillary hypoplasia is defined as a growth deficiency that can impact one or more of the three dimensions: transversal (maxillary endognathia, anterior or complete), sagittal (maxillary retrusion), or vertical.

It is now widely accepted that surgery, and especially early surgical intervention, plays a primary role in causing this condition, since the facial, and particularly maxillary, growth of untreated adults affected by UCLP is nearly identical to that of the normal population (Shetye et al., 2004; Wlodarczyk et al., 2022).

There is a lack of evidence when it comes to determining the optimal treatment protocol, and no true consensus has been reached yet. Shaw et al. reported that 194 different protocols for unilateral CLP (UCLP) are carried out in Europe among 201 centers, and that none of these was found to be superior over another (Shaw et al., 2001). Regardless of the surgical protocol, it is clearly recognized that primary surgery plays a crucial role in subsequent maxillary development.

The majority of clinically treated UCLP patients aged 5 years already exhibit a midface retrusion and narrowing, with a class III malocclusion resulting from a maxilla that is underdeveloped in all three dimensions (Shetye et al., 2004). The etiology of maxillary growth deficiency may be attributed to multiple factors: (1) the intrinsic defect resulting from deficient embryonic development leading to the cleft itself, and the associated inherent hypoplasia of the palatal tissues, which varies according to the type and severity of the cleft (Chiu et al., 2011; Harila et al., 2013); (2) the genetic legacy for midface growth and facial pattern inherited from both parents (Honda, 1995); and (3) the growth inhibition as a result of corrective primary surgery due to generated scar retractions (Ye et al., 2015). In addition to the surgical procedure, the timing of, and differences in, primary protocols play a major role in maxillary sequelae (Bénateau et al., 2021; Wiggman et al., 2013). It is well established that the outcomes, both in terms of appearance and function, hinge upon the quality of the initial treatment.

Treating patients with CLP poses a significant challenge, particularly in ensuring that the initial treatment has a minimal effect on maxillary growth. Evaluating different treatment methods is thus essential for adjusting primary protocols and guaranteeing the quality of the final result. Primary surgical protocol assessment typically occurs around the age of 5, to mitigate biases arising from secondary surgeries or orthodontic treatment.

The aim of our study was to assess maxillary growth in 5-year-old patients with complete UCLP, who received primary treatment according to three different surgical protocols. Our secondary objective was to investigate the influence of potential predictive factors of poor craniofacial growth defects: initial cleft severity; absence of permanent lateral incisor on the cleft side, and family history of class III pattern.