Background: Diverse findings have been reported for the cranial base angle (CBA) in patients with CLP (cleft lip and palate) and non-CLP controls. Objective: The aim of this study is to assess and evaluate the CBA in patients with CLP and non-CLP controls. Methods: Data from PubMed, OVID Technologies, Inc., Cochrane, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Scopus, Web of Science, and EMBASE for Excerpta Medica dataBASE (EMBASE) with relevant terms was extracted until December 31, 2020. Inclusion criteria were data of patients with non-syndromic unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP). In the case of UCLP and BCLP, patients with craniofacial syndromes were excluded. The study proposal was registered with PROSPERO (Registration number: CRD42021228632). Results: Fifteen studies with a total of 2032 participants were included for the systematic review and 14 studies with a total of 1972 participants were included for the meta-analysis. The risk of bias was assessed using the Modified Newcastle Ottawa scale under seven domains by two authors. Thirteen studies were graded as "good" and two as "satisfactory." The CBA in patients with CLP were greater than the non CLP Class I controls in six of the 15 studies. CBA was greater in patients with CLP than non-CLP controls by 1.21° (95% CI of 0.19-2.22). Meta-analysis reported considerable heterogeneity (I2 = 86%). Anterior (ACB) and posterior cranial base (PCB) lengths were shorter in patients with CLP than in the non-cleft Class I controls by 2.14 mm (95% CI of 0.99-3.30) and 2.06 mm (95% CI of 1.52-2.60), respectively. Conclusion: Most studies were graded as good. Patients with CLP had greater CBA and shorter ACB and PCB lengths when compared to non-CLP controls.
Keywords: cleft lip and palate.; cranial base angle; cranial base flexure; systematic review.