|STATE OF THE ART
|Year : 2019 | Volume
| Issue : 2 | Page : 65-72
Management of velopharyngeal insufficiency: The evolution of care and the current state of the art
Ann W Kummer
Division of Speech-Language Pathology, Department of Patient Services, Cincinnati Children's Hospital Medical Center; University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA
|Date of Web Publication||7-Aug-2019|
Dr. Ann W Kummer
Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3026
Source of Support: None, Conflict of Interest: None
Velopharyngeal insufficiency (VPI) is a condition in which there is incomplete closure of the velopharyngeal valve during speech production. This results in hypernasality and/or audible nasal emission. Nasal emission can cause additional secondary characteristics, including weak or omitted consonants, compensatory articulation productions, short utterance length, and even dysphonia. Overall, this condition affects the quality and intelligibility of speech production, which can have a significant effect on the individual's communication and social interactions. This article provides a brief overview of how the management of VPI has evolved over the past 40 years (which is the extent of this author's career). In addition, the current state of the art in VPI management is discussed from this author's perspective. Finally, a pathway is suggested for the future evolution of care for patients affected by VPI.
Keywords: Speech prosthetic devices, speech therapy, surgical management, velopharyngeal dysfunction, velopharyngeal insufficiency
|How to cite this article:|
Kummer AW. Management of velopharyngeal insufficiency: The evolution of care and the current state of the art. J Cleft Lip Palate Craniofac Anomal 2019;6:65-72
|How to cite this URL:|
Kummer AW. Management of velopharyngeal insufficiency: The evolution of care and the current state of the art. J Cleft Lip Palate Craniofac Anomal [serial online] 2019 [cited 2020 May 25];6:65-72. Available from: http://www.jclpca.org/text.asp?2019/6/2/65/264091
| Introduction|| |
Velopharyngeal insufficiency (VPI) is a type of velopharyngeal dysfunction that is caused by abnormal velopharyngeal structure. A history of cleft palate (or submucous cleft) is the most common cause of VPI. In fact, it has been estimated that approximately 20%–30% of children with cleft palate will demonstrate some degree of VPI, despite successful palatoplasty. In these cases, the velum is typically not of sufficient length, particularly in midline, to close firmly against the posterior pharyngeal wall during oral speech production. VPI can be due to other causes, including cervical spine anomalies (causing a deep pharynx), amniotic bands, adenoidectomy, maxillary advancement, and treatment for oropharyngeal tumors.
VPI can have a significant effect on the quality and intelligibility of speech. This is because it causes a leak of sound and/or airflow into the nasal cavity, which reduces the sound and/or airflow in the oral cavity. This can result in hypernasality, which is a resonance disorder as a result of excessive sound in the nasal cavity during speech. The leak of airflow can also result in audible nasal emission, particularly on pressure-sensitive consonants (plosives, fricatives, and affricates).
The way that VPI is evaluated and treated has changed over the past four decades and even the terminology that we use to describe it has become more precise. The following describes some of these changes that have occurred in the management of VPI.
| Terminology|| |
In the late 1900s, the literature was full of inconsistencies in the use of terminology for disorders of the velopharyngeal valve. The most common terms, which were used interchangeably, included velopharyngeal inadequacy, velopharyngeal impairment, VPI, velopharyngeal incompetence, and velopharyngeal dysfunction. The need for more specificity in terminology was first advocated by Trost and then by others who felt that the terminology should be not only consistent but also specific to general etiology., Over the years, there has been a general consensus regarding the use of terminology, which is as follows:
- VPI is used to describe an anatomical or structural defect that prevents adequate velopharyngeal closure, such as cleft palate
- Velopharyngeal incompetence is used to refer to a neurophysiological disorder that results in poor movement of the velopharyngeal structures, such as stroke, cerebral palsy, head trauma, or neuromuscular disease
- Velopharyngeal mislearning is used to describe an articulation disorder in which there is a substitution of a pharyngeal or nasal sound for an oral sound, such as the use of a pharyngeal fricative for a sibilant sound (s, z, sh, zh, ch, and j) or an n/l substitution.
With this terminology, VPI (for both VPI and incompetence) is used for disorders that are medically based and therefore require physical management (e.g., surgery or a prosthetic device). In contrast, velopharyngeal mislearning is a functional disorder and therefore requires speech therapy only.
| Evaluation|| |
The evaluation of velopharyngeal function begins with a perceptual evaluation of speech and resonance by a speech-language pathologist (SLP), preferably one with training and experience in this specialty area. The evaluation should include a test of individual speech sound production, in addition to testing for the presence of nasal emission and hypernasality.
Conventionally, SLPs have used single-word articulation tests to evaluate speech sound production. One of the early articulation tests, the Templin–Darley Tests of Articulation, included a subsection for testing specific sounds that are typically affected by VPI. This test is now out of print. In recent years, however, many SLPs have abandoned these tests because single words are not a good representation of the child's actual speech abilities. In addition, the tests are expensive and time-consuming. Instead, tests that involve repetition of syllables and sentences are used. These tests are actually more valid in representing normal speech production, they provide better diagnostic information, and they are free.
Supplemental tests of velopharyngeal insufficiency
Over the years, SLPs have used some supplemental procedures to confirm or rule out the presence of hypernasality and/or nasal emission. These procedures include the following:
- Dental mirror: A small mirror (preferably a dental mirror with a narrow rim) is placed under the nares while the patient produces pressure-sensitive sounds [Figure 1]. If the mirror clouds up with condensation, it indicates nasal emission. This test has many false positives because of normal nasal breathing
- Air paddle: A paper “paddle” is placed in front of the nose during the production of pressure-sensitive sounds [Figure 2]. If the paddle moves, it indicates nasal emission. This test is highly unreliable
- See-Scape: The See-Scape (PRO-ED) is a pneumatic tube device. A “nasal olive” on one end of a flexible tube goes into the child's naris. The other end of the flexible tube is connected to a rigid plastic vertical tube with a STYROFOAM™ float inside. As the child repeats pressure-sensitive phonemes, the float will rise in the vertical tube if there is nasal air emission [Figure 3]. This device is expensive and it cannot be disinfected with the Styrofoam float. In addition, the Styrofoam shrinks over time, making the device useless
- Feeling the sides of the nose: Vibration from hypernasality can sometimes be felt by placing the fingers lightly on the side of the patient's nose. This feeling can be simulated by prolonging an ‘m' and feeling the vibration on the nasal cartilage. Vibration from nasal emission can sometimes be felt on the sides (cartilage) of the nose when the nasal emission is due to a small velopharyngeal opening. This is not a very sensitive test, however
- Cul-de-Sac test: If there is a suspicion of hypernasality, the examiner can have the child repeat oral syllables or sentences and then repeat them with the nose pinched closed. If there is a shift in resonance, this confirms hypernasality. For several reasons, this test is not very reliable.
|Figure 1: The use of a dental mirror to detect condensation as a result of nasal emission|
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|Figure 2: The use of a paper air paddle to detect the presence of nasal emission|
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Although these tests have some utility, they are not consistently reliable in determining both hypernasality and nasal emission. Therefore, in more recent years, the trend is to amplify the sound of the hypernasality and/or nasal emission. In this way, the examiner can detect evidence of even a very small or inconsistent opening of the velopharyngeal valve during speech.
- Listening tube/straw: Amplification of sound from the velopharyngeal valve can be done using a simple straw (preferably a bending straw). The short end of the straw is placed at the entrance of the child's nostril and the long end is placed near the examiner's ear [Figure 4]. A piece of suction tubing or other type of tube can also be used as a listening tube [Figure 5]
- The child is asked to repeat oral sounds in syllable repetition and in sentences. If there is either hypernasality or nasal emission, the sound will be amplified as it passes through the narrow tube (just as if using a stethoscope), and therefore, it will be heard loudly when it occurs.
|Figure 5: (a and b) The use of tubing to detect hypernasality or nasal emission|
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Prediction of velopharyngeal gap size
As noted above, VPI can result in either hypernasality, nasal emission, or a combination of both. The audibility of the characteristic depends on the size of the velopharyngeal opening. However, the size of the opening does not correlate well with the perceived severity of the speech disorder and the effect on intelligibility. In recent years, we have developed a better understanding of this lack of correlation by examining the separate effects of gap size on acoustics (resonance) versus aerodynamics (airflow). Given what is known about acoustics and flow, there is actually an inverse relationship between the audibility of hypernasality and audibility of nasal emission., With this understanding, we can now predict velopharyngeal gap size based on the perceptual features of the individual's speech [Figure 6].
|Figure 6: Perceptual characteristics related to relative velopharyngeal gap size. Reprinted with permission from Kummer AW. (2020). Cleft Palate and Craniofacial Conditions: A Comprehensive Guide to Clinical Management, 4thEdition. Burlington, MA: Jones & Bartlett Learning|
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With a large velopharyngeal opening, hypernasality is the most predominant characteristic of speech. Nasal emission is severe, but it is essentially inaudible because it flows through the opening without much resistance (even if it was audible, the sound of the nasal emission would be masked by the hypernasality.) The nasal emission causes a severe reduction of airflow in the oral cavity, making consonants weak in intensity and pressure. In addition, utterance length is shortened due to the need to take frequent breaths to replenish the airflow. Finally, compensatory productions (with articulation placement in the pharynx where there is airflow) are commonly developed to increase intelligibility.
With a mid-sized velopharyngeal opening, there are less hypernasality and more audible nasal emission. This is because with a relatively smaller opening, there is more resistance to the flow of air as it goes through the valve, causing audible friction. Furthermore, there is more intraoral airflow, so consonants are stronger and utterance length is less affected.
Small velopharyngeal openings are typically characterized by normal resonance but inconsistent and very audible nasal emission. This is often in the form of a nasal rustle/nasal turbulence, which is a loud and distracting bubbly sound., As air goes through small opening, it is released with increased pressure, which causes audible bubbling of secretions.
Nasometry is a method that is used to quantify the acoustic correlates of velopharyngeal function during speech production. This is done by collecting objective data regarding the relative amount of nasal versus oral acoustic energy that occurs during the production of a speech passage. Nasometry was designed to supplement the perceptual assessment of resonance which, by its nature, is subjective.
The first instrument to measure nasal and oral acoustic energy during speech was called TONAR, an acronym for The Oral-Nasal Acoustic Ratio. It was later updated, revised, and then renamed TONAR II. Although the TONAR instruments provided objective data, the data acquisition was somewhat unreliable. Therefore, Fletcher et al. developed the Nasometer™, which was first introduced by Kay Elemetrics Corporation in 1986. In 2002, a second version of the Nasometer was released as Nasometer II, Model 6400. With this model, data capture was done with digital circuitry, and the speech signal was recorded to allow for playback.
The latest hardware and software version is the Nasometer II, Model 6450 (PENTAX Medical). This version contains a built-in sound chip in the hardware and can be used with a laptop in addition to a desktop. In recent years, the headset for data capture has been replaced with a handheld version [Figure 7]. This device is better for infection control and is also better tolerated by young children.
Nasometry captures acoustic energy from both the nasal (N) cavity and oral (O) cavity during speech and then calculates the average ratio of nasal over total (nasal plus oral) acoustic energy for the passage. This ratio is converted to a percentage value called the nasalance score. The nasalance score can be depicted, therefore, as follows: Nasalance = N ÷ (N + O) × 100. When an individual's score is compared to normative data, a judgment can be made regarding the normalcy of resonance. High scores in comparison to normative data suggest hypernasality, whereas low scores in comparison to normative data suggest hyponasality. The severity of the nasalance score does not correlate well with the size of the velopharyngeal opening due to the interaction of hypernasality and audible nasal emission. However, nasometry is very consistent in indicating normal velopharyngeal function.
Multiview videofluoroscopy has been used for decades as a way to confirm the presence of a velopharyngeal opening and estimate the size of that opening. The evolution of the use of radiography for evaluation of velopharyngeal function began, however, with the use of a simple two-dimensional lateral cephalometric X-ray.
In the 1950s and 1960s, lateral cephalometric X-rays were used extensively as part of the evaluation of VPI. A “lateral ceph” was taken during prolongation of a vowel or a sustained /s/ and a still X-ray was taken of the midsagittal section of the velopharyngeal portal. This view showed velar length and height during sound prolongation and gave an indication as to whether the velum contacted the posterior pharyngeal wall for that sustained phoneme. Although somewhat advantageous at the time, there were multiple limitations with this method of assessment, including the fact that it provided only a two-dimensional view of the velopharyngeal valve and did not show movement during speech.
A methodological advancement in radiography of the velopharyngeal valve occurred in the late 1950s with the introduction of cineradiography. The “cine study” technique involved taking a series of 16–24 frames of radiographs per se cond, which were recorded on motion picture film. Multiple views were taken to account for the three-dimensional aspects of the velopharyngeal valve. One major disadvantage of this procedure was the relatively high dosage of radiation per study.
The most significant methodological advancement in radiographic assessment procedures was the introduction of videofluoroscopy in the late 1960s.,, Unlike with cineradiography, this technique allows simultaneous audio recording of the speech, which greatly enhances the diagnostic value of this procedure. In addition, videofluoroscopy is done with far less radiation than a cine study.
Multiview videofluoroscopy has been used since the 1970s to confirm the presence of a velopharyngeal opening and estimate the size of that opening. The cause of VPI can be differentiated between a short velum and poor velar movement. In comparison with nasopharyngoscopy, videofluoroscopy is superior in showing the vertical movement of the velum during speech. It also provides a view of the entire length of the posterior pharyngeal wall during closure, which cannot be seen with nasopharyngoscopy.
Although videofluoroscopy has been a valuable tool in VPI management for decades, its use has been declining over the years with more providers now using nasopharyngoscopy as their preferred method of assessment.
Nasopharyngoscopy is an endoscopic evaluation of the velopharyngeal function [Figure 8]. It is done by passing a nasopharyngoscopy through the middle meatus of the nasal cavity and then turning the scope down to view the entire velopharyngeal valve during speech.
The idea to use endoscopy to evaluate velopharyngeal function began in the 1960s. In 1966, Taub described the use of an oral panendoscope for the assessment of velopharyngeal function. The panendoscope consisted of an optical tube that could be placed in the mouth and then turned upward for visualization of the velopharyngeal sphincter. The use of this scope did not gain wide acceptance, however, because of its many issues. First, the placement of the tube in the mouth interfered with the normal production of speech. However, the optical tube was too big for insertion in the nose. Another problem was that the light bulb generated a dangerous amount of heat in addition to an electrical hazard for the individual.
In 1969, Pigott et al. described the use of a rigid endoscope that was slender enough to be inserted through the nose but large enough to allow observation of the velopharyngeal portal at rest and during speech. This endoscope provided a wide-angle view of about 70°, which allowed visualization of most of the port. However, because it was rigid, the scope could not be maneuvered for additional assessment of the lateral edges of the port or to see farther down into the pharynx or vocal tract. In addition, it was very difficult to insert and caused significant pain, so it was not well tolerated by patients.
In 1975, Miyazaki et al. described a side-viewing flexible endoscope. With this design, the scope remained in a horizontal position, and the opening at the side of the scope gave the examiner the same view as with the rigid scope. However, because of the side opening, the scope could not be manipulated easily to provide a view of both the horizontal and vertical aspects of the velopharyngeal valve.
The biggest advancement in the use of endoscopy for evaluation of VPI occurred in the mid-1970s and the 1980s with the development of the end-viewing flexible fiber-optic nasopharyngoscope., The flexible scope is smaller in circumference than the rigid scope (ranging from 2 mm to 3.3 mm), making it much easier to pass transnasally and better tolerated by for patients. The tip of this scope is flexible and can turn down to view the velopharyngeal port from various angles. It can even be moved farther down the pharynx for a view of the larynx and the vocal folds. The latest version of these scopes also has a “chip-on-the-tip,” which is a small digital camera on the tip of the scope for better optics.
Nasopharyngoscopy is now widely used for the clinical evaluation of velopharyngeal function. In contrast to videofluoroscopy, nasopharyngoscopy allows the examiner to see the entire velopharyngeal port and with far better clarity than videofluoroscopy. In addition, the examiner can determine the relative size, location, and cause of a velopharyngeal opening, which is important for surgical planning. Finally, there are anomalies that can be seen through nasopharyngoscopy, which are not clearly visible (or visible at all) through videofluoroscopy, including evidence of an occult submucous cleft, enlarged adenoids, pulsation of the carotid artery on the pharyngeal wall, tonsils in the airway, vocal nodules, and the effects of previous VPI surgery on function. Therefore, most cleft/craniofacial centers in the United States now use nasopharyngoscopy primarily or even exclusively over videofluoroscopy for the visual evaluation of velopharyngeal function.
| Treatment|| |
The treatment of speech disorders secondary to VPI includes physical management (surgery or a prosthesis) or behavioral management (speech therapy). The ultimate goal of treatment is to achieve normal articulation placement and complete closure of the velopharyngeal valve during oral speech production, while maintaining a patent nasopharyngeal airway for nasal breathing and sleep.
Historically, access to surgery for VPI was limited, and the success of the surgical procedures was not as high as it is currently. Therefore, a large number of patients with VPI were managed with prosthetic devices. These devices include the palatal lift, which holds the velum in position against the posterior pharyngeal wall (assuming it has sufficient length), and the speech bulb obturator, which fills in the space between the velum and the posterior pharyngeal wall with an acrylic bulb. With better surgical procedures and better access to care, surgical correction of VPI is more commonly done., Prosthetic devices are still used in certain patients, however, particularly those with complex conditions and those with less access to surgical care.
There are several surgical procedures that have been used over the years to correct VPI. These include the following:
- Pharyngeal flap: The pharyngeal flap is the most commonly used procedure for correction of VPI. It is done by raising a flap from the pharynx and inserting it into the velum, thus creating a passive, soft-tissue obturator in the middle of the velopharyngeal port
- Sphincter pharyngoplasty: The sphincter pharyngoplasty also called Orticochea sphincteroplasty has undergone a series of modifications over the years., It is done by raising myomucosal flaps from the posterior faucial pillars. These flaps are then rotated posteriorly and inset into a transverse incision in the nasopharynx. This effectively narrows the lateral aspects of the pharynx and leaves a single round port in the center of the pharynx. Although this procedure was expected to create a dynamic sphincter, studies have shown that the muscle fibers are actually passive. Therefore, it actually serves as a lateral port obturator
- Furlow Z-palatoplasty: The Furlow Z-plasty technique was first used as a primary cleft palate repair procedure. It is now also being to lengthen the velum when there is a narrow velopharyngeal opening and the original repair was a different approach,
- Pharyngeal wall augmentation: For very small velopharyngeal openings, some surgeons use posterior pharyngeal wall augmentation. With this procedure, a substance is injected in the posterior pharyngeal wall in the area of the velopharyngeal opening. Various materials have been used for augmentation, including Teflon™ (which is no longer used), calcium hydroxylapatite, cartilage, fascia, silicone, porous polyethylene, proplast, fat, and most recently, Deflux®.
All of the above procedures have a risk of undercorrection, resulting in persistent VPI. The pharyngeal flap and sphincter pharyngoplasty also have a risk of causing upper airway obstruction and obstructive sleep apnea (OSA) because by design, these procedures partially obstruct the pharynx. To lengthen the palate and reduce the risk of upper airway obstruction, a buccal flap, which is a relatively new procedure, is being used by some surgeons.
- Buccal (buccinator myomucosal) flap: With this procedure, bilateral buccal myomucosal flaps are raised and transferred to the velum in a modified pushback procedure. The effectively lengthens the velum and does not obstruct the nasopharynx.
Choice of procedure
Some surgeons have a preferred surgical procedure for the treatment of VPI based on their training, experience, and even bias. However, VPI comes in all shapes and sizes. Therefore, a more progressive approach would be to find the “hole” and then choose the procedure that will best fill that hole. Using this approach, it would initially make sense to choose a pharyngeal flap for the treatment of midline gaps (which are most common following a cleft palate repair) and large gaps in the anterior–posterior dimension. However, the buccal flap shows great promise and may prove to be as effective as the pharyngeal flap with less risk of OSA. A sphincter pharyngoplasty would be most effective with lateral gaps, as are common with hemifacial microsomia. The Furlow Z-plasty would be most effective with narrow, coronal openings, and finally, pharyngeal augmentation should be considered in small, localized openings.
In the past (and sometimes even now), there were those who believed that speech therapy could correct VPI or at least improve velopharyngeal function. There were also those who believed that “intensive” speech therapy should be done before surgical correction. These assumptions were not based on evidence (or even common sense). Fortunately, these assumptions are now being dispelled.
It is important to note that speech therapy cannot correct VPI. VPI is a condition that is due to abnormal structure, and speech therapy does not change structure. In addition, there are no exercises that will lengthen the velum, and if there were, the child would have to do them the rest of his life to maintain any gains. Overall, a structural defect, including even a small velopharyngeal opening, requires physical management.
In contrast, speech therapy is done to correct abnormal function (e.g., abnormal articulation placement). Therefore, speech therapy is effective in correcting compensatory articulation productions that develop as a result of VPI. The placement of these compensatory productions occurs in the pharynx, where there is airflow. Because of this placement, the air is released through the nose, causing nasal emission. Therefore, if the child developed this type of placement due to VPI, there will still be nasal emission after surgical correction of VPI. By changing the placement of these sounds from pharyngeal to oral through speech therapy, the nasal emission will be eliminated.
Speech therapy prior to correction of VPI is not very effective, particularly if the VPI is the cause of the abnormal placement. VPI should always be surgically corrected first (unless there are airway issues). Once the structure is normalized, therapy will be much more effective. If the child is under the age of five, he may even begin to use oral phonemes correctly on his own.
| Pathway for the Evolution of Care|| |
There is no doubt that children affected by VPI today have a much better prognosis for normal speech than children affected by VPI 40 years ago. We have better evaluation procedures, particularly with nasometry and nasopharyngoscopy, and surgical procedures continue to improve. However, we can and should do better.
To continue to improve the quality of our treatment of VPI, we need to be able to compare outcomes of VPI surgery to see what works best. Unfortunately, outcome studies in the literature show a significant variability in how the characteristics of VPI are evaluated and how the outcomes are reported. Ratings of severity of hypernasality or nasal emission are subjective and are inherently unreliable. In addition, severity can be affected by utterance length, loudness, phonemic complexity, and level of effort and fatigue. Finally, objective measures are often not included in the outcome data. As a result, it is virtually impossible to compare results in order to determine best surgical procedures.
Therefore, to really improve care, my suggestion is as follows: we need to have large, multicenter studies to determine the percentage of patients who obtain normal velopharyngeal function following surgery for cleft palate or VPI. This should be defined through both perceptual assessment and objective measures, as follows:
- Normal speech and resonance (e.g., no hypernasality or audible nasal emission) as judged by an experience SLP
- Normal nasometry scores (e.g., average nasalance scores for oral passages at 22% or under).
With this “apples-to-apples” comparison, we will be able to determine which surgical procedures (and which surgeons) have the best outcomes and under which circumstances. This will provide a benchmark of best procedures for others to follow.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Trost JE. Articulatory additions to the classical description of the speech of persons with cleft palate. Cleft Palate J 1981;18:193-203.
Loney RW, Bloem TJ. Velopharyngeal dysfunction: Recommendations for use of nomenclature. Cleft Palate J 1987;24:334-5.
Trost-Cardamone JE. Coming to terms with VPI: A response to Loney and Bloem. Cleft Palate J 1989;26:68-70.
Templin MC, Darley FL. The Templin-Darley Tests of Articulation: A Manual and Discussion of Articulation Testing. Des Moines: University of Iowa; 1969.
Kummer AW, Briggs M, Lee L. The relationship between the characteristics of speech and velopharyngeal gap size. Cleft Palate Craniofac J 2003;40:590-6.
Kummer AW, Curtis C, Wiggs M, Lee L, Strife JL. Comparison of velopharyngeal gap size in patients with hypernasality, hypernasality and nasal emission, or nasal turbulence (rustle) as the primary speech characteristic. Cleft Palate Craniofac J 1992;29:152-6.
Fletcher SG, Bishop ME. Measurement of nasality with tonar. Cleft Palate J 1970;7:610-21.
Fletcher SG. Theory and use of tonar II: A status report. Biocommun Res Rep 1976;1:1-38.
Fletcher SG, Adams L, McCutcheon MJ. Cleft palate speech assessment through oral-nasal acoustic measures. In: Bzoch KR, editor. Communicative Disorders Related to Cleft Lip and Palate. Boston: College Hill Press; 1989. p. 246-57.
Skolnick ML. Video velopharyngography in patients with nasal speech, with emphasis on lateral pharyngeal motion in velopharyngeal closure. Radiology 1969;93:747-55.
Skolnick ML. Videofluoroscopic examination of the velopharyngeal portal during phonation in lateral and base projections – A new technique for studying the mechanics of closure. Cleft Palate J 1970;7:803-16.
Skolnick ML, McCall GN. Radiological evaluation of velopharyngeal closure. JAMA 1971;218:96.
Taub S. The taub oral panendoscope: A new technique. Cleft Palate J 1966;3:328-46.
Pigott RW, Bensen JF, White FD. Nasendoscopy in the diagnosis of velopharyngeal incompetence. Plast Reconstr Surg 1969;43:141-7.
Miyazaki T, Matsuya T, Yamaoka M. Fiberscopic methods for assessment of velopharyngeal closure during various activities. Cleft Palate J 1975;12:107-14.
Croft CB, Shprintzen RJ, Rakoff SJ. Patterns of velopharyngeal valving in normal and cleft palate subjects: A multi-view videofluoroscopic and nasendoscopic study. Laryngoscope 1981;91:265-71.
Shprintzen RJ, Lewin ML, Croft CB, Daniller AI, Argamaso RV, Ship AG, et al.
Acomprehensive study of pharyngeal flap surgery: Tailor made flaps. Cleft Palate J 1979;16:46-55.
Lam DJ, Starr JR, Perkins JA, Lewis CW, Eblen LE, Dunlap J, et al.
Acomparison of nasendoscopy and multiview videofluoroscopy in assessing velopharyngeal insufficiency. Otolaryngol Head Neck Surg 2006;134:394-402.
Kummer AW, Hosseinabad HH, Redle E, Clark S. Protocols for reporting speech outcomes following palatoplasty or velopharyngeal surgery: A literature review. Plast Reconstr Surg Glob Open 2019;7:e2151.
Delgado AA, Schaaf NG, Emrich L. Trends in prosthodontic treatment of cleft palate patients at one institution: A twenty-one year review. Cleft Palate Craniofac J 1992;29:425-8.
Reisberg DJ. Dental and prosthodontic care for patients with cleft or craniofacial conditions. Cleft Palate Craniofac J 2000;37:534-7.
Cable BB, Canady JW, Karnell MP, Karnell LH, Malick DN. Pharyngeal flap surgery: Long-term outcomes at the University of Iowa. Plast Reconstr Surg 2004;113:475-8.
Orticochea M. Results of the dynamic muscle sphincter operation in cleft palates. Br J Plast Surg 1970;23:108-14.
Jackson IT. Sphincter pharyngoplasty. Clin Plast Surg 1985;12:711-7.
Jackson IT, McGlynn MJ, Huskie CF, Dip IP. Velopharyngeal incompetence in the absence of cleft palate: Results of treatment in 20 cases. Plast Reconstr Surg 1980;66:211-3.
Perkins JA, Lewis CW, Gruss JS, Eblen LE, Sie KC. Furlow palatoplasty for management of velopharyngeal insufficiency: A prospective study of 148 consecutive patients. Plast Reconstr Surg 2005;116:72-80.
Sie KC, Gruss JS. Results with furlow palatoplasty in the management of velopharyngeal insufficiency. Plast Reconstr Surg 2002;109:2588-9.
Gray SD, Pinborough-Zimmerman J, Catten M. Posterior wall augmentation for treatment of velopharyngeal insufficiency. Otolaryngol Head Neck Surg 1999;121:107-12.
Varghese D, Datta S, Varghese A. Use of buccal myomucosal flap for palatal lengthening in cleft palate patient: Experience of 20 cases. Contemp Clin Dent 2015;6:S36-40.
Kummer AW, Clark SL, Redle EE, Thomsen LL, Billmire DA. Current practice in assessing and reporting speech outcomes of cleft palate and velopharyngeal surgery: A survey of cleft palate/craniofacial professionals. Cleft Palate Craniofac J 2012;49:146-52.
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