Dystrophic-Like Alterations Characterize Orbicularis Oris and Palatopharyngeal Muscles in Patients Affected by Cleft Lip and Palate

Abstract

This study analyzed histological and histochemical features of specimens of the orbicularis oris muscle, and palatal and pharyngeal muscles biopsied during surgery from 33 patients affected by cleft lip and palate. Three groups were studied: 20 patients affected by cleft palate with or without cleft lip (at the time of primary palatoplasty), seven by cleft lip with or without cleft palate (primary lip closure), and six by cleft lip with or without cleft palate (secondary cheiloplasty). Muscle sections were stained with hematoxylin-eosin, modified Gomori trichrome, ATPase reaction at pH 9.4, and NADH-TR. Analyzed parameters included organization, muscle fiber size and type, nuclear changes, presence of ragged-red fibers, degree of fibrosis, and presence of inflammatory infiltrate. In all patients who underwent primary palatoplasty and lip closure we noted dystrophic-like alterations of orbicularis oris and palatopharyngeal muscles, such as variability of fiber size, fiber disorganization, and increased fibrosis. The same alterations were found in adult patients submitted to secondary cheiloplasty, notwithstanding surgical repair. Furthermore, in all groups neither neurogenic atrophy nor ragged-red fibers or inflammatory infiltrate were detected. Muscle damage is a constant event in this deformity, and it could play an important role in its etiopathogenesis. Muscular biopsy during cheiloplasty and palatoplasty could offer useful information about muscle condition and possible functional recovery in cleft lip and palate patients.