Creating a Superiorly Based Pharyngeal Flap: Is Prominence of C1 Superior Enough, and Will Adenoid Pad Be in the Way?

Abstract

Background: Positioning the pharyngeal flap base high along the posterior pharyngeal wall is essential for optimizing speech outcomes. Objective data on where to place the flap base are lacking. Further, adenoid tissue can restrict cephalad positioning of the flap. This study aimed to improve the design of the pharyngeal flap by measuring the distance from the first cervical vertebrae (C1) to the palatal plane, and the adenoid depth in children undergoing evaluation for velopharyngeal insufficiency.

Methods: This retrospective cross-sectional study analyzed magnetic resonance imaging (MRI) scans of the velopharynx and measured the distance between C1 and the palatal plane, and the adenoid depth at the level of the palatal plane in millimeters.

Results: Thirty-four patients met the inclusion criteria. The mean age at the time of MRI was 7.4 years (range: 3.9-11.9 y). The anterior tubercle of C1 was below the palatal plane in 97% (n = 33) of patients. On average, this landmark was 10.5 mm (SD = 5.0) below the palatal plane. Adenoid tissue was present at the level of the palatal plane in 91% (n = 31) of patients.

Conclusions: Positioning the pharyngeal flap base at C1 is too low to aid with velopharyngeal closure. Further, adenoid tissue is frequently present at the level of velopharyngeal closure, limiting superior positioning of the pharyngeal flap base. When this occurs, surgeons should consider adenoidectomy before pharyngeal flap surgery. Preoperative MRI may be beneficial for planning pharyngeal flap positioning relative to C1 and assessing adenoid tissue at the palatal plane.

Fig. 1.

Postoperative MRI from a patient with persistent hypernasality after pharyngeal flap placement. The pharyngeal flap base is above the anterior tubercle of C1 but below the palatal plane. Further, the adenoid tissue would prevent elevation of the pharyngeal flap base to the palatal plane. The adenoid is outlined in yellow; C1 is shown in green. The palatal plane is shown by a white dashed line.

Fig. 2.

The distance from above the anterior tubercle of C1 (green) to the palatal plane (horizontal dashed line) was obtained as a vertical linear measurement along the posterior pharyngeal wall, as shown in blue.

Fig. 3.

Depth of the adenoid pad at the palatal plane. The palatal plane and posterior pharyngeal wall are shown with white dashed lines. The adenoid is outlined in yellow. The anterior tubercle of C1 is shown in green. The red line indicates the horizontal, linear measurement for the depth of the adenoid at the palatal plane.

Fig. 4.

The distance between above the anterior tubercle of C1 and the palatal plane is shown across patients in 1-mm increments. C1 was not the same height as the palatal plane in 97% (n = 33) of patients. On average, C1 was 10.5 mm (SD = 5.0; range 0–18.7) below the palatal plane. Basing a pharyngeal flap at C1 may tether the palate inferiorly.

Fig. 5.

Adenoid depth in millimeters at the level of the palatal plane is shown across patients in 1-mm increments. The mean adenoid depth at the level of the palatal plane was 9.5 mm (SD = 4.8; range 0–19.3). For surgeons who base a pharyngeal flap at the palatal plane, 91% of patients younger than 12 years will have adenoid tissue that may impede cephalad positioning of the flap.

Fig. 6.

In A, the adenoid does not preclude cephalad positioning of a pharyngeal flap at the palatal plane or C1. In B, adenoid tissue is present at the palatal plane but not at C1. In C, adenoid tissue is present at the palatal plane and C1. A pharyngeal flap placed at C1 may tether the palate inferiorly, rather than assist with elevation of the palate during velopharyngeal closure.