Disclosure
Velopharyngeal dysfunction (VPD) is the constellation of speech production disorders that includes velopharyngeal insufficiency, incompetence, and incorrect learning. Anomalous velopharyngeal closure prevents appropriate speech production. Patients with VPD may present with hypernasality, nasal emission, or facial grimacing. In their attempt to be understood, affected patients often develop compensatory maladaptive articulations that are very difficult to reverse if left untreated. Many times, this failure of the sphincteric mechanism is the result of a structural defect of the pharyngeal walls or the velum (soft palate) at the level of the nasopharynx. Increasingly, speech scientists and surgeons have converted to using the term VPD in place of the older and more entrenched term VPI (Loney, 1987; Folkins, 1988), which can be confusing because various authors use it to connote velopharyngeal insufficiency, velopharyngeal incompetence, velopharyngeal inadequacy, or velopharyngeal incorrect learning. In common parlance, VPI generally means that sphincteric closure is incomplete during production of oral sounds of speech. While the descriptors used in VPI are used synonymously, they are not necessarily equivalent. In contrast, the term VPD does not assume or exclude any possible origin of speech symptoms. Anatomic, myoneural, behavioral, or combinations of disorders are all possible causes of the dysfunction. VPD occurs in approximately 20% of children who undergo palatoplasty (Witt, 1993). In-depth evaluation of symptoms, causes, and treatment outcomes are critical aspects of treating patients with VPD. Patients with VPD should be treated within in the context of multidisciplinary team care. In 1988, an international working group convened to standardize definitions and assessment methodologies (Golding-Kushner, 1990). The working group strongly recommended implementing a multidisciplinary team approach and using multimodal instruments to evaluate preoperative and postoperative speech outcomes. The group asserted that comprehensive analysis of specific causes of speech production disorders, through perceptual and instrumental measures of velopharyngeal function, allows for customized treatment algorithms for specific patients. Role of the speech pathologist The surgeon, speech pathologist, and other health care providers work closely together to achieve the goal of optimal treatment for the patient. These practitioners collaborate in their reviews of the in-depth diagnostic assessment results and the individual patient's medical history. Consensus evaluation usually provides an appropriate course of management for affected individuals and may yield a differential diagnosis that leads to differential management (Marsh, 2003). Ideally, this means that care providers attempt to match the gap size, shape, and velopharyngeal closing pattern to the most appropriate intervention. Surgeons, as well as lay people, are usually capable of recognizing speech “differences.” Perception of the difference does not require a sophisticated understanding of speech physiology, but discrimination of the causes and severity or magnitude of that difference and treatment planning do require a sophisticated understanding of speech physiology. Speech and language pathologists are particularly adept at sorting out the components of a communication disorder and their respective weights, which frequently dictates what receives surgical attention, not whether it receives attention. This is both a skill and a talent that surgeons and lay people rarely possess. The relationship between speech pathologist and surgeon Making the distinction between velopharyngeal valve dysfunction (structural defect) and speech dysfunction is critical. For example, consider the following analogy: If a newly licensed 16-year-old driver is involved in a motor vehicle accident, differentiating between a mechanical failure of the car and a failure of the just-learning driver to maintain control of the vehicle is important. Was the driver taking mind-altering drugs? Was a mechanical problem with the car at fault or was the driver's inexperience or misbehavior at fault? The answers to these questions are basic to the investigational algorithm. They tell the investigator where to look next, keeping in mind that both might sides may have been to blame. The same logic holds true for the evaluation and management of VPD. Is the velopharyngeal valve (eg, car) at fault or the speech disorder (eg, driver) at fault? The answer to this question tells the investigator what to do next and who should do it. Treatment may involve fixing the velopharyngeal valve (ie, necessitating a surgeon's expertise) or teaching the patient (ie, necessitating speech and language pathologists' expertise). Examining the velopharyngeal valve should be quite straightforward. A simple mirror test at the bedside, with a definitive yes-or-no answer, can help determine if the patient can eliminate nasal escape. The presence of hypernasality is much more difficult to evaluate. Using vocal, nonverbal testing can obviate such problems as phoneme-specific velopharyngeal insufficiency. An astute speech and language pathologist should be able to make the determination despite the confounding glottal stops, fistulae, and other factors. Surgeons must emphasize to parents, patients, and other providers that surgical success can be anticipated with respect to nasal escape and hypernasality. Then, the speech and language pathologists assume the responsibility of helping the patient achieve speech and language success, including articulation and other facets of verbal communication.
The anatomy of the velopharynx (ie, palate, posterior pharyngeal wall, airway) is depicted in Image 1. The composite movements of the lateral pharyngeal walls, the velum, and posterior pharyngeal walls close the velopharyngeal port in deglutition and during oral speech sounds; they open the port for breathing and some nasalized articulations. Patterns of closure as observed on preoperative instrumental assessments include coronal, sagittal, bow-tie, circular, and Passavant (see Image 2). Basic speech terminology for the surgeon: Presumably, care providers representing the various disciplines of the cleft team use the same nomenclature so they can effectively organize and communicate their knowledge. Trost-Cardamone developed a useful taxonomy to classify possible causative factors of VPD. In velopharyngeal insufficiency, the tissue to accomplish closure of the velopharyngeal sphincter is insufficient. Additionally, velopharyngeal insufficiency can be due to structural etiologies, such as mechanical interferences with closure, including excessively large tonsils and/or webbing of the posterior tonsillar pillars (D'Antonio, 1996). Velopharyngeal incompetence occurs with neurogenic etiologies such as motor disorders. Velopharyngeal incorrect learning may be the result of phoneme-specific nasal emission and deafness or hearing impairment. Hypernasality and hyponasality are voice tones shaped by the mouth and oropharynx. Hypernasality is excessive resonance in the nasal cavity that is usually related to VPD due to a lack of a barrier between the oral and nasal cavities. While hypernasality usually refers to velopharyngeal sphincteric function, it may be secondary to a fistula or unrepaired cleft palate. The following is a lexicon of additional terms used to describe some elements of cleft palate speech dysfunction (Kummer, 2001; Wyatt, 1996):
When a patient is referred for surgical treatment of VPD, the first steps should be to try to elicit specific information germane to speech problems, cleft palate, or both. Questions Try to ascertain from both the parents and the patient whether the speech production disorder has caused psychosocial stigmatization, peer teasing, or frustration in not being able to communicate with others. Nasal regurgitation of liquids or solids and/or an associated hygiene problem may be the source of social embarrassment. Findings During intraoral inspection, look for palatal fistulae, enlarged tonsils, visibly aberrant carotid pulsations along the posterior pharyngeal wall, a prominent adenoid pad, palatal zona pellucida (trough), a palpable notch at the junction of the hard and soft palate, or a bifid uvula. Check for velar mobility (elevation) on speech tasks, and, thus, indirectly assess levator muscle status. Provocative tests Simple bedside maneuvers can help define the speech problem. A pocket-size, handheld mirror can be placed beneath the patient's nares in order to observe 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. Provocative samples of speech are designed to elicit phonemes that require velopharyngeal closure. 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 require maximal pulmonary pressures and thus can be used as a brief screening for integrity of plosive sounds. Try to ascertain overall intelligibility in running, spontaneous, connected speech. Patients with suspected VPD are incapable of achieving velopharyngeal closure upon maximum effort when producing properly articulated phonemes that require closure. Importantly, errors in these sequences of sounds should serve only as a red flag for the surgeon; interpretive significance of the errors should be left to the qualified speech and language pathologist. 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 “stimulability” of performance during visualization of dynamic speech activity. Arguably, the speech pathologist best understands and interprets the movements and the articulatory and vocal structures. The author usually concludes the interview with extemporaneous hand-drawn pictures of the velopharyngeal mechanism to explain the complex speech mechanism to the patient and family. Airway evaluation The tonsils and adenoids are often important components of the velopharyngeal closure mechanism. Occasionally, hypertrophic tonsils may herniate into the velopharyngeal port so that lymphoid obstruction may actually be a source of speech dysfunction. Other times, enlarged tonsils may limit the technical placement of pharyngoplasty flaps or their sheer size may efface the myomucosal pillars, making flap elevation difficult. Similarly, enlarged, friable, and hemorrhagic adenoids may inhibit performance of velopharyngeal surgery, and their presence may even compromise the outcome of surgical intervention if they contribute to flap dehiscence. In these circumstances, preoperative tonsillectomy and/or adenoidectomy may be indicated. This decision, however, must be made cautiously and in conjunction with the team otolaryngologist and speech pathologist. Tonsillectomy, and particularly adenoidectomy, should be avoided in any patient with symptoms of VPD until a differential diagnosis is established and a management plan is formulated by care providers and accepted by the patient and family. The clinical manifestations of VPD are likely to worsen after adenoidectomy. If performing an adenoidectomy is necessary to facilitate the technical execution of velopharyngeal surgery, the patient and family must be duly warned about this predictable deterioration. The author usually waits 3 months after adenoidectomy before proceeding with velopharyngeal surgery. Personally communicating with the team otolaryngologist to be certain he or she preserves the precious posterior tonsillar pillar tissue for later construction of the port is wise. Instrumental assessment of speech Several diagnostic modalities can be used to assess speech production in patients who demonstrate symptoms of VPD. Detailed descriptions of these modalities are found in published articles (Witt, 2000). These modalities include video-recorded standard perceptual speech screenings (ie, acoustic evaluation of sounds or listener judgments), nasendoscopy, nasometry, aerodynamics, and fluoroscopic speech evaluations. The 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 a speech and language pathologist, 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. |
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Nonsurgical and treatment optionsIn a small number of cases, prosthetic management may be the best solution for VPD. Prostheses include the following:
Prostheses may be used as a temporary reversible trial for which they provide diagnostic information in patients with variable VPD in whom it is unclear whether surgery alone will provide significant improvement in speech quality. A prosthesis may be useful in some patients with a short, scarred velum or in other patients with a long supple paretic velum. Some authors have hypothesized that prostheses may stimulate neuromuscular activity (Tachimura, 2002), although definitive proof for this is lacking. (Witt, Cleft Palate Craniofac J, 1995: 469-75). Contraindications to surgeryVelopharyngeal narrowing procedures are not appropriate for patients who meet the following criteria:
The author does not believe that visible pulsations on the posterior pharyngeal wall, indicating aberrant carotid arteries, should be an absolute contraindication to surgery (Witt, Plast Reconstr Surg, 1998: 1184-95). What about aberrant carotid arteries? Anomalous internal carotid arteries have been shown to be a frequent feature of velocardiofacial syndrome. These vessels pose a potential risk for iatrogenic injury and hemorrhage during velopharyngeal narrowing procedures. Various forms of cervical vascular imaging studies (eg, CT scanning, angiography) have been advocated as aids to surgery by defining the preoperative vascular anatomy. Nevertheless, whether these studies alter either the conduct or outcome of operations on the velopharynx remains unclear. Iatrogenic injuries to the carotid artery during velopharyngeal surgery are strikingly absent in the extant literature. Occasionally, transmission of vascular pulsations through floppy redundant mucosa may artificially masquerade as an ominous vessel. Additionally, tortuous mesially displaced vessels observed at one point have been shown to straighten out laterally on later studies. The issue of how should the surgeon should approach the problem of aberrantly located carotid vessels is provocative and controversial and deserves overt answers from each participating surgeon; however, safety must prevail as the first priority. When displaced vessels are identified, surgeons are faced with a few options. In the first, the surgeon may abandon the procedure. In the second, the surgeon may "operate around" the vessels. In the third, the surgeon may choose to perform one procedure instead of another, ie, sphincter pharyngoplasty instead of pharyngeal flap. (Theoretically, performance of the latter procedure could expose a vessel over the full length of the flap.) The author is more comfortable operating in the presence of these aberrant structures, provided he can reposition the flap(s) so as not to interfere with their presence, expose the vessel to oropharyngeal secretions, or compromise the execution of the procedure. The author does not routinely obtain preoperative vascular imaging studies on all patients. The author, in performing more than 150 velopharyngeal narrowing procedures, has not been compelled to abort a single procedure. Awareness of their presence comes from careful inspection of the small operative field, palpation of aberrant vessels intraoperatively, and cautious surgery. Surgical procedures for VPDPartial obstruction, either temporary or permanent, of the velopharyngeal port is the unifying feature of most current operative management strategies for VPD. The choice of either of the 2 broad categories of options for VPD depends on the patient's specific diagnosis The first option category is (1) lengthening the palate by retropositioning the velum, which can be achieved with a V-Y pushback procedure, an intravelar veloplasty (Marsh 1989), or a double-opposing Z-plasty (D'Antonio, 1997), and (2) palatal re-repair (Sommerlad, 2002). The second option category is reduction of the static opening between the nasal and oral pharynges (LaRossa, 2000; Sloan, 2000), which is considered a velopharyngeal narrowing procedure. These may be accomplished with a pharyngeal flap or sphincter pharyngoplasty. The pharyngeal flap creates a single subtotal central obstruction of the velopharyngeal port, leaving 2 open ports laterally. Alternatively, sphincter pharyngoplasty may be performed to diminish the cross-sectional area of the central port. Posterior pharyngeal wall augmentation is another method of treating resonance disorders, and this procedure is used in various centers around the world with variable success. This article focuses primarily on pharyngeal flap and sphincter pharyngoplasty procedures. Pharyngeal flap
Sphincter pharyngoplasty The goal of sphincter pharyngoplasty is to narrow the central velopharyngeal orifice, thus minimizing airflow through the nose during speech. Theoretically, sphincter pharyngoplasty tightens the central orifice without creating lateral ports, resulting in an opposite configuration of the velopharynx compared with the pharyngeal flap. Sphincter pharyngoplasty was first described more than 50 years ago, yet only recently has it become the procedure of choice among many surgeons. Because of insufficient collation of data, a detailed description of risks, benefits, and long-term outcomes has not been confirmed. The original concept of sphincter pharyngoplasty was described by Hynes (1950); it has since been modified by others, including Orticochea (1968). The procedure rearranges palatopharyngeus myomucosal flaps raised from the posterior tonsillar pillars, which are transposed to the posterior pharyngeal wall and to each other. This procedure may result in less airway morbidity than the pharyngeal flap (Witt, 1996) and, conceptually, is more physiologic, although these impressions reflect the author's personal bias and remain unproven.
Risks involved with surgical VPD treatment include acute obstructive sleep apnea, dehiscence (procedure failure), and a potential/theoretical risk of iatrogenic injury to anomalous internal carotid arteries. Sleep disturbances as a consequence of sphincter pharyngoplasty may range from simple snoring to acute obstructive sleep apnea. Rarely is sleep apnea so severe as to require hospitalization. This adverse effect appears to occur in a substantial percentage of patients surgically managed for VPD, as suggested in a preliminary report by Witt et al in which the incidence was 13% of 58 patients observed (Witt, 1996). Complete nasopharyngeal obstruction should be a rare complication, assuming that all raw surfaces were properly fulfilled at the primary pharyngoplasty. The author has not encountered it in his practice. He has seen patients in referral who presented with the unpleasant triad of sleep apnea/snoring, hyponasal resonance, and retained secretions/maxillary sinusitis (see Image 22). Velopharyngeal surgery is still more of an art than a science. The goal is to create a subtotal obstruction that improves resonance but avoids airway morbidity. Still, in approximately 10% of cases, reoperation is necessary to treat residual hypernasality or nasal emission.
Several studies have been published in support of each of the available options for management of velopharyngeal insufficiency; however, most of the data have not been validated by large numbers of patients, nor have these results been subjected to critical analysis. Most of these studies lack a multidisciplinary evaluation, standardized evaluation/treatment criteria, and methods for assessing surgical outcome. For example, several different types of sphincter pharyngoplasties have been described, although commonly, they have been grouped together as though they were the same. These procedures differ regarding transposition of the flaps, use of muscle tissues, levels of insertion, and whether a synchronous pharyngeal flap is used. Other uncontrolled variables include the status of the tonsils and whether a full-thickness transverse cut is made in the posterior pharyngeal wall mucosa. This heterogeneity of sphincter pharyngoplasties explains some of the difficulty in describing postoperative outcomes. Cleft palate populations, migratory patterns of treating physicians, and dogmatism among surgeons regarding the best technique are all inherently unstable. Additionally, the study designs often do not include rigorous documentation of the preintervention, periintervention, and postintervention states or the methodology for evaluation of the intervention. Achieving a high compliance rate from a patient population stratified for age, sex, socioeconomic factors, and number of surgical interventions is an arduous task. The outcome assessment instrument must be designed to allow analysis of intrarater and interrater reliabilities of all the extramural raters and, at the same time, not be so cumbersome and burdensome as to reduce compliance. Future diagnostic assessment and treatment modalities Exciting new technologies are on the horizon, such as dynamic magnetic resonance imaging of the velopharynx, that may soon be available for clinical use. Magnetic resonance data can be reformatted to simulate endoscopy. Planar images may be converted to 3-dimensional volumes. While in its infancy, this technology may someday allow clinicians feel as if they can actually go inside the anatomic structures they have scanned with "fly throughs," focusing on specific pathologies. This has the potential of evolving into noninvasive endoscopy, assuming that it can meet or exceed the criteria standards currently available (D'Antonio, 1988).
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