Velopharyngeal Dysfunction Workup

Acquisition of objective, quantitative, preoperative, and postoperative evaluation data allows for a rational informed decision regarding surgical and nonsurgical intervention.^{[15, 16, 17, 18]} Determining the precise etiology of the velopharyngeal dysfunction (VPD) is paramount before embarking on treatment modalities.

Simple bedside maneuvers can help define the speech problem. A handheld pocketsize mirror can be placed beneath the patient’s nares to allow observation of nasal airflow (audible air nasal emission). A straw may be placed at the corner of the patient’s mouth while he or she recites a speech task. The listener at the other end of the straw can perceive amplified air sound, unmasked hypernasality, or both.

Listen to both spontaneous speech and structured provocative samples of speech. Try to ascertain overall intelligibility in running, spontaneous, connected speech. Patients with suspected VPD are incapable of achieving velopharyngeal closure (VPC) on maximum effort when producing properly articulated phonemes that require closure.

Provocative samples of speech are designed to elicit phonemes that require VPC. A representative sequence might include the following words or phrases: “ma, ma, ma,” “puppy,” “puffy,” “muffin,” “pamper,” “sissy,” “go get a big egg,” “bye-bye Bobby,” “Katy likes cookies,” “Sally sees the sky.” Production of voiceless consonants such as p, t, k, s, f, and sh requires maximal pulmonary pressures and thus can be used as a brief screening for the integrity of plosive sounds.

It must be emphasized that for the surgeon, errors in these sequences of sounds should serve only as a red flag; interpretation of the significance of these errors should be left to a qualified speech and language pathologist (SLP). Most physicians are unfamiliar with the behavioral variables that can affect velopharyngeal function, such as oronasal discrimination proficiency, the presence of maladaptive articulations, the effects of coarticulation, the range of articulatory motion, and the contribution of speaking effort.

The speech evaluation should include attention to error types and the “stimulability” of performance during visualization of dynamic speech activity. Arguably, the SLP is the care provider who best understands and interprets the movements and the articulatory and vocal structures. (See Voice and Resonance Evaluation.)

Several diagnostic modalities can be used to assess speech production in patients who demonstrate symptoms of VPD; detailed descriptions are found in published articles.^[19] These modalities include video-recorded standard perceptual speech screenings (ie, acoustic evaluation of sounds or listener judgments), nasoendoscopy, nasometry, aerodynamics, and fluoroscopic speech evaluations. (See Fiberoptic Nasoendoscopy and Videofluoroscopy.)

These studies have the advantage of being readily archived on digital media for review, for study, and for strobe analysis, among other tasks. Usually, test results are reviewed by the interdisciplinary velopharyngeal staff of specialists, including an SLP, an otolaryngologist, a prosthodontist, and a plastic surgeon.

If cephalometric evaluations are available, they can facilitate diagnosis. Tracings can quantitatively assess the ratio of velar length to velopharyngeal depth, which is often a good predictor of patients who require physical management of the velopharynx.

Exciting new technologies are on the horizon, such as dynamic magnetic resonance imaging (MRI) of the velopharynx, which may soon be available for clinical use.

MRI data can be reformatted to simulate endoscopy. Planar images may be converted to 3-dimensional volumes. Although this technology is still in its infancy, someday it may allow clinicians to feel as if they can actually go inside the anatomic structures they have scanned with “fly-throughs,” focusing on specific pathologies. Such an approach has the potential of evolving into noninvasive endoscopy, provided that it can meet or exceed the criteria standards currently available.^[20]

The SLP can offer informative data to help determine the appropriate course of treatment for VPD by completing a voice and resonance evaluation. A thorough voice and resonance evaluation for VPD includes articulation assessment, oral motor assessment, and measurement of nasal airflow.

Articulation assessment

Objective measures of articulation ability, such as the Arizona Articulation Proficiency Scale, are administered at the single-word level to determine articulation errors. The patient’s speech intelligibility is then rated on the basis of this scale, and the dysfunction is characterized as mild, moderate, or severe.

The SLP also describes the types of articulation errors, including nasal emissions, glottal stops, and nasal fricatives. The patient’s responses to corrections of articulation errors, distortions, nasal emissions, and hypernasality are then assessed to determine prognosis for improvement with speech therapy.

Oral motor assessment

A subjective oral motor assessment is completed by observing the range of motion and speed of the lips and tongue, as well as elevation of the soft palate and velum with pronunciation of the phoneme /ah/. Overall facial symmetry and muscle tone are also noted.

Measurement of nasal airflow

The MacKay-Kummer sensory nerve action potential (SNAP) test is administered to children aged 3-9 years with the Kay Elemetrics Nasometer to assess the ratio of oral airflow to nasal airflow. For children aged 9 years and older and for adults, the Zoo Passage, Rainbow Passage, and Nasal Sentences are substituted as standard reading passages.

Nasometer results are compared with normative data. A score that is 3 standard deviations above the mean indicates hypernasal resonance (ie, speaking with too much airflow and resonance in the nasal cavity). A score that is 3 standard deviations below the mean indicates hyponasality, which is defined as insufficient nasal resonance for the nasal phonemes (ie, /m/, /n/, /ng/).

Visualization of the velopharyngeal mechanism can be achieved by means of either fiberoptic nasoendoscopy (FN) or multiplanar videofluoroscopy (VF).

After voice and resonance evaluation, a determination of the need for FN is made on the basis of the test results. Indications for FN include hypernasality (either consistent or inconsistent), poor oral airflow with nasal escape, and structural abnormalities of the soft palate.^[21] If none of these conditions exist and the patient presents with sufficient oral airflow for most phonemes, speech therapy typically is recommended with periodic reevaluation before completion of FN.

Sedation is not typically used for this procedure. In certain patients, however, such as children younger than 5 and older children who are uncooperative, sedation may be helpful. If sedation is to be used, oral midazolam (Versed) is administered at a dose of 0.5 mg/kg (up to 10 mg) and given 15-20 minutes before FN. This dose provides adequate amnesia and sedation while allowing the child to perform the necessary tasks for the examination. Higher doses of midazolam may make the examination difficult because the child is sedated too heavily.

Before placement of the fiberscope, the nasal cavity is examined for any obstructions that may inhibit passage of the scope into the nasopharynx. The nose then is decongested and anesthetized with a mixture of 4% lidocaine and 0.05% oxymetazoline hydrochloride, which is sprayed into the nose with an atomizing device.

The fiberscope is passed through the nostril, superior to the inferior turbinate, to the posterior nasal choana (see the image below). Passage along the floor of the nose does not position the fiberscope high enough to allow for visualization of the entire velopharyngeal sphincter.

With the fiberscope in place, the patient is asked to repeat a series of words and sentences loaded with phonemes that require increased oral airflow (eg, plosives, fricatives) so that the velar closure pattern can be observed. The examination is videotaped for later review. Patients who are unable to vocalize these phonemes may be grossly assessed by this technique by looking at overall VPC and identifying any deficiency in each of the specific planes of closure.

FN is superior to VF for assessing VPD in that it allows direct visualization of the velopharyngeal sphincter. This is especially important in the postsurgical patient when the velopharyngeal anatomy is altered, as occurs with placement of a pharyngeal flap. Compared with VF, FN is slightly more invasive and requires a moderate degree of cooperation from the child to obtain an adequate examination.

VF is performed by the SLP in conjunction with a radiologist. Unlike FN, VF can be used to see through tissues so that movement can be discerned at all vertical and horizontal positions within the pharynx. A 3-dimensional perspective can be gained using frontal, lateral, and base or Towne projections.

VF is usually performed without sedation. Barium is instilled through the nose with a nose dropper to contrast soft tissues against the surrounding skeletal structures. Fluoroscopic views are then obtained in the lateral, anteroposterior (frontal), and base projections while the patient articulates phonemes that require increased oral airflow. The lateral view helps the examiner visualize the velum, posterior pharyngeal wall, and tongue. The frontal view enables assessment of the lateral pharyngeal walls along the entire vertical extent of the pharynx.

The advantage of VF is that it allows more precise localization of the level of VPC by measuring the level against the spine. Observation of the tongue is also important because the tongue may contribute to closure in a compensatory fashion by lifting the palate, as is seen in swallowing. This information could be missed with FN alone. VF has the obvious disadvantage of radiation exposure. In addition, when normal anatomy is altered (eg, after surgery), interpretation of the images may be difficult.

Assessment of velopharyngeal closure pattern

Four main patterns of VPC have been described on the basis of FN and VF: coronal, sagittal, circular, and circular with the Passavant ridge. (See Pathophysiology.) The type of closure pattern is determined by the relative contribution of the palate and lateral pharyngeal walls to closure of the velopharyngeal sphincter.

Determination of a patient’s closure pattern is clinically significant, as is the determination of the vertical level of closure. The type of closure pattern determines the type of surgical intervention, because surgical intervention is most effective when it targets the point of maximal pharyngeal motion.^[22]

Preoperative tonsillectomy and adenoidectomy

An important preoperative consideration is the need for adenoidectomy, tonsillectomy, or both.^[23] In most instances, preoperative adenoidectomy is necessary for either sphincter pharyngoplasty or a pharyngeal flap procedure. Indications for preoperative tonsillectomy vary.

In the case of sphincter pharyngoplasty, adenoidectomy makes room for placement of the lateral pharyngeal wall flaps. Failure to remove the adenoids makes attachment of the flaps to the posterior pharyngeal wall difficult.

The need for tonsillectomy before pharyngoplasty is determined by the degree of obstruction. This determination is somewhat subjective and is based on the size of the tonsils and whether they interfere with the raising of the lateral pharyngeal wall flaps. Leaving the tonsils in place often helps preserve the posterior tonsillar pillars, which are used to create the pharyngoplasty flaps.

Before a pharyngeal flap procedure, removal of both the tonsils and the adenoids often is necessary. Placement of a pharyngeal flap makes subsequent adenoidectomy difficult if not impossible, and residual adenoid tissue may obstruct the lateral pharyngeal ports. Similarly, the tonsils may obstruct the pharyngeal ports from below, so their removal typically is recommended.

Other considerations

One factor to consider in preoperative planning is whether breathing is obstructed preoperatively. Placement of a pharyngeal flap increases the degree of nasal airway obstruction and may worsen any preexisting obstructive sleep apnea. This is especially true in patients with Pierre Robin syndrome, in which retrognathia may result in upper airway obstruction. In such instances, consideration should be given to pharyngoplasty instead of a pharyngeal flap because the risk of worsening airway obstruction postoperatively is lower with pharyngoplasty. Children with both obstructive sleep apnea and VPD should have treatment of the sleep apnea prior to surgical management of the VPD.

The location of the internal carotid arteries (ICAs) as they traverse the lateral pharynx is also an important consideration, especially in patients with velocardiofacial syndrome (VCF).^[24] In patients with VCF syndrome, the ICA can take a more medial position and thus is theoretically at risk for injury with pharyngeal surgery. Preoperative evaluation with contrast-enhanced computed tomography (CT) scanning or magnetic resonance angiography (MRA) can elucidate the course of the ICA.^[25]

In practice, the ICA will lateralize when the head is extended for surgery and will not be in the operative field during pharyngoplasty or pharyngeal flap surgery, and the presence of a medially displaced ICA is not necessarily a surgical contraindication.

The presence of a primary bleeding disorder (ie, hemophilia or von Willebrand disease) may complicate surgical management. Likewise, anticoagulation for reasons such as a prosthetic heart valve may be a contraindication to surgery.