The biopsy specimens were oriented for serial transverse sectioning, mounted on slices of cork in OTC compound (optimal temperature cutting compound) (Tissue Tek Miles Laboratories, Naperville, Ill), and frozen in liquid methyl-butane chilled with liquid nitrogen. Biopsy specimens were also obtained from 3 adult cadavers (all male age range, 80-86 years) within 24 hours post mortem before embalming. All patients provided informed consent to undergo biopsies, which were approved by the Institutional Review Board at the State University of New York Upstate Medical University, New York. C, Magnified T2-weighted magnetic resonance image of a patient without velocardiofacial syndrome, midsagittal plane, depicting the thickness of the superior pharyngeal constrictor muscle and the locations at which it was measured.Ī biopsy specimen of the SPC muscle at the midline of the posterior pharyngeal wall was obtained during routine superior pharyngeal flap surgery in 9 children (3 female and 6 male age range, 4-12 years) with VCFS. B, Magnified T2-weighted magnetic resonance image of a patient with velocardiofacial syndrome, midsagittal plane, depicting the thickness of the superior pharyngeal constrictor muscle and the locations at which it was measured. A, T2-weighted magnetic resonance image of a patient with velocardiofacial syndrome, midsagittal plane, depicting the superior pharyngeal constrictor muscle. The average of the 3 measurements was taken as the thickness of the muscle.įigure 1. Using computer software (eFilm 1.5 Medical Imaging System eFilm Medical Inc, Milwaukee, Wis), measurements were taken in the midsagittal plane at the following 3 levels for each patient: the level of the first cervical vertebra, the midpoint of the second cervical vertebra, and the inferior aspect of the second cervical vertebra ( Figure 1). Patients without VCFS did not have a primary myopathy. The thickness of the SPC muscle in 26 patients with VCFS (18 male and 8 female age range, 3-29 years) and 26 patients without VCFS (18 male and 8 female age range, 3-27 years) was determined using T1- and T2-weighted cervical spine and brain magnetic resonance images (MRIs). The purpose of this study is to evaluate the thickness, histology, and histochemistry of the SPC muscle in patients with VCFS to determine whether a muscle irregularity exists that might contribute to the hypotonia seen in these patients. However, further characterization of the SPC muscle in humans has received little attention. Golding-Kushner 3 demonstrated a decrease in the thickness of the posterior pharyngeal wall on plain radiographs in patients with VCFS. Motor innervation to the SPC muscle is derived from the pharyngeal plexus (vagus and glossopharyngeal nerves). The muscle extends from the pharyngeal tubercle of the skull superiorly to approximately the level of the third cervical vertebra inferiorly. The fibers then curve posteriorly to insert into the median raphe of the pharynx. The SPC muscle arises from the medial pterygoid plate and hamulus. 6 An abnormality in this muscle can adversely affect velopharyngeal function, resulting in hypotonia and hypernasal speech. 4, 5 The superior pharyngeal constrictor (SPC) muscle is largely responsible for movement of the lateral and posterior pharyngeal walls. 3Ĭlosure of the velopharyngeal valve is complex and involves posterosuperior movement of the soft palate (velum), medial movement of the lateral pharyngeal walls, and, in some individuals, anterior movement of the posterior pharyngeal wall. Decreased thickness of the posterior pharyngeal wall has been implicated. An inherent abnormality in one or more of the muscles responsible for closure of the velopharyngeal valve, an abnormality in the central nervous system, or a combination of both might contribute to the hypotonia. However, the etiology of this hypotonia has not been elucidated. 1, 2 Pharyngeal hypotonia, one of the most common findings in VCFS, contributes to the development of hypernasal speech. One of the most recognizable features of VCFS is the development of hypernasal speech, which occurs in approximately 75% of individuals with VCFS. The syndrome has been reported to have more than 180 clinical features, none of which occurs with 100% frequency. Velocardiofacial syndrome, which has an autosomal dominant inheritance, is a complex disorder with significant phenotypic variability and variable penetrance. VELOCARDIOFACIAL syndrome (VCFS) is one of the most common multiple anomaly syndromes in humans.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |