Growth Effects on Velopharyngeal Anatomy Within the First 2 Years of Life

Growth and Symmetry of the Levator Veli Palatini Muscle Within the First Two Years of Life

OBJECTIVE

To quantify differences in levator veli palatini (LVP) muscle dimensions based on age, sex, and race and determine the typical range of asymmetry between the left and right sides of the LVP under age 2.

DESIGN

Retrospective cohort study.

SETTING

Children's tertiary care hospital.

PARTICIPANTS

A retrospective chart review of non-cleft patients under 2 who received a volumetric FLAIR MRI sequence within the past 18 months identified 216 patient scans. Exclusion criteria left 200 scans for analysis. Measurements of the LVP were obtained consistent with previous literature.

INTERVENTIONS

Corrected age, sex, and race.

MAIN OUTCOME MEASURE(S)

LVP muscle dimensions.

RESULTS

A significant (P < .0001) difference between corrected age groups based on the overall combination of LVP variables after controlling for sex and race. Significant age differences included average extravelar length (P < .0001), average intravelar length (P < .0001), midline thickness (P < .0001), and average (P < .0001) and difference (P = .0413) in insertion thickness. Significant sex differences included average intravelar length (P = .0412) and average insertion thickness (P = .0281). Significant race differences included average insertion thickness (P = .0334) and difference in intravelar length (P = .0473). Differences between left and right total length (P = .0491) and angle of origin (P < .0001) were significant.

CONCLUSIONS

Differences in LVP morphology were observed in individuals under 2 years or age related to age, sex, and race. While asymmetry was significant in some dimensions, it varied by age range.

Craniofacial and Velopharyngeal Dimensions in Infants 0-12 Months: Between- and Within-Group Differences Based on Age and Sex

PURPOSE

The purpose of the present study is to (a) provide quantitative data on the growth of levator veli palatini (LVP), velopharyngeal (VP), and craniofacial dimensions in children under 12 months while controlling for corrected age and sex and (b) compare variability within age and sex groups.

METHOD

Magnetic resonance imaging scans of 75 infants between 0 and 12 months were measured and divided into four age groups. These data were obtained as part of a larger retrospective study. Following exclusion criteria, scans were analyzed, and dependent variables were obtained.

RESULTS

There was a statistically significant (p < .0001) difference between corrected age groups on LVP muscle, VP, and craniofacial variables while controlling for sex. Significant growth effects were observed for LVP length (p < .0001), extravelar length (p < .0001), intravelar length (p = .048), midline thickness (p = .0001), origin-origin distance (p < .0001), velar length (p < .0001), velar thickness (p = .003), nasion-sella turcica distance (p < .0001), sella turcica-basion distance (p < .0001), and hard palate length (p < .0001). Significant sex effects were observed for pharyngeal depth (p = .026) and effective VP ratio (p = .014). When age was treated as a continuous variable, similar results were observed for all variables except pharyngeal depth. Within-group comparisons revealed the most variability occurs between 3 and 5.99 months for LVP and craniofacial variables and between 9 and 11.99 months of age for VP variables. Male participants demonstrated greater variability than female participants.

CONCLUSIONS

Differences were observed in LVP, VP, and craniofacial variables in children under 12 months while controlling for sex. Males demonstrated larger values and greater variability for most variables.

Measurement Matters: MRI Analysis of Differing Anatomic Measurement Techniques for Velar Length and the Velopharyngeal Needs Ratio

Background

Advances in imaging tools provide opportunities to enhance how velopharyngeal (VP) variables are quantified to facilitate surgical decisions. The purpose of this study was to use magnetic resonance imaging (MRI) to determine if quantitative differences were present between measures of linear and curvilinear velar length, and subsequently, the VP needs ratio.

Methods

Data were prospectively collected from patients presenting with repaired cleft palate and/or congenital palatal insufficiency with or without VPI at a single center tertiary children's hospital. Quantitative measures of the velopharynx using a novel nonsedated MRI protocol were obtained. Paired samples t tests were conducted to assess if differences were present between the VP needs ratio and measurements of linear and curvilinear velar length at rest and during sustained phonation. Intraclass correlation coefficients were calculated to assess intra/inter-rater reliability.

Results

Significant differences were present between measurements of linear and curvilinear velar length at rest (P ≤ 0.001) and during sustained phonation (P ≤ 0.001). Significant differences were also present in the VP needs ratio (P ≤ 0.001). Curvilinear velar length at rest and during sustained phonation was longer than that of linear velar length at rest and during sustained phonation. No significant differences were observed between measures of effective velar length (P = 0.393).

Conclusions

Measurement differences influence the VP needs ratio. This may have implications for comparisons to previously reported normative reference values and for those who are anatomically at risk for VPI. MRI provides an enhanced imaging modality to assess normative benchmarks and the anatomic variables used to define VP anatomy for clinical decision-making.

Sex Differences in Velopharyngeal Anatomy of 9- and 10-Year-Old Children

OBJECTIVE

Understanding the normal anatomy of velopharyngeal (VP) mechanism and the emergence of sexual dimorphism provides valuable insights into differences of VP anatomy among males and females. The purpose of this study is to examine sex differences in VP anatomy in a large data set of 3,248 9- and 10-year-old children.

METHOD

Static three-dimensional magnetic resonance imaging was used to compare five VP characteristics including velar length, velar thickness, effective velar length, levator veli palatini muscle length, and pharyngeal depth between age-matched males (n = 1,670) and females (n = 1,578). Additionally, these dimensions were used to determine the VP ratio and effective VP ratio.

RESULTS

Males showed significantly larger dimensions for all VP distances and significantly lower ratios of velar length and effective velar length to pharyngeal depth (p < .05). The magnitude of these effect sizes was small to medium, with Cohen's d values ranging from 0.12 to 0.63. Additionally, the VP ratio and effective VP ratio are lower among males compared to females (p < .05).

CONCLUSIONS

Results suggest the presence of sexual dimorphism in the VP mechanism among 9- and 10-year-old children. These findings emphasize the necessity of using different normative data for males and females when making comparisons to patients with cleft palate.

An Exploratory Investigation of the Palatoglossus Muscle in Children Using Magnetic Resonance Imaging

PURPOSE

There is currently little evidence reporting the typical morphology of the palatoglossus (PG) muscle. The primary purpose of this exploratory study is to determine whether magnetic resonance imaging (MRI) methods used to quantify the morphology of the levator veli palatini (LVP) muscle can be applied to the PG. The secondary purpose is to provide preliminary data regarding the relationship between the LVP and PG muscles in children.

METHOD

Ten children between ages of 4 and 7 years participated in this study. Each participant was scanned using a nonsedated, child-friendly protocol with a T2-weighted, three-dimensional anatomical scan to obtain images of the oropharyngeal anatomy. Custom, oblique-coronal image planes were created to visualize and measure the LVP and PG muscles in their entirety from origin to insertion. Thermo Scientific Amira Software was used to obtain 2D measurements of PG muscle length, width, velar insertion distance, lingual insertion distance, and several angle measurements.

RESULTS

The PG ranged from 17.95 to 26.96 mm in length across participants. Velar insertion distance ranged from 17.22 to 30.95 mm. Lingual insertion distance ranged from 26.91 to 36.02 mm. Width ranged from 2.32 to 3.08 mm. The angle formed by the PG and LVP muscle planes ranged from 7.3° to 52.7°. The LVP insertion angle ranged from 42.5° to 75.9°. The PG insertion angle ranged from 16.9° to 52.3°.

CONCLUSIONS

MRI was successful in visualizing the PG muscle. The PG was consistent in size and shape within an individual participant but varied across the participant cohort.