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Velopharyngeal Insufficiency


Velopharyngeal Insufficiency

Article Author:
Allen Young
Article Editor:
Alycia Spinner
Updated:
9/25/2020 10:50:04 AM
For CME on this topic:
Velopharyngeal Insufficiency CME
PubMed Link:
Velopharyngeal Insufficiency

Introduction

Velopharyngeal dysfunction (VPD) is a disorder of the velopharyngeal (VP) sphincter or valve, which functions to separate the nasal and oral cavities during speech, swallowing, vomiting, blowing, and sucking. When the soft palate and pharyngeal walls are unable to form an effective seal, an abnormal connection between the nasal and oral cavities leads to hypernasal speech, increased nasal resonance, nasal regurgitation, nasal emission, and decreased intraoral pressure during speech. The overall result is decreased speech intelligibility and significant functional and social impairment.

Diagnosis and treatment require a multidisciplinary approach centered around speech-language pathology, otolaryngology, and plastic surgery. Velopharyngeal dysfunction is the favored nomenclature, as it denotes a deficit of the velopharyngeal closure without implying a specific cause. It can be further subdivided into velopharyngeal insufficiency, incompetence, and mislearning, which provides additional information on the causation. Velopharyngeal insufficiency suggests a structural defect, incompetent us due to neurologic dysfunction, and mislearning is due to learned errors in articulation.[1]

Etiology

Velopharyngeal dysfunction may result from incomplete closure of the velopharyngeal sphincter, which controls the airflow into the nasal cavity during speech and prevents nasal regurgitation during swallowing. VPD can occur secondary to structural deficits, neurological disorders, faulty learning, or as a syndromic finding.[2][3]  

  1. Structural: The velopharyngeal sphincter may fail to obtain a seal secondary to a cleft palate (overt or submucosal), congenital short soft palate, nasopharyngeal disproportion, poor sphincter mobility from tonsillar hypertrophy, or scarring from prior surgery.[4] Iatrogenic causes such cleft palate repair can cause or worsen VPD through poor mobility of the soft palate due to surgical scarring, misalignment of the levator veli palatini muscles, or creation of a palatal fistula. Adenoidectomy can enlarge the velopharyngeal port so much that it prevents adequate closure.[5][6]
  2. Neuromuscular: Neurologic or musculoskeletal injury may result in incompetent closure of an anatomically-sound velopharyngeal sphincter. Causes include head trauma, stroke, cerebral palsy, myopathy, muscular dystrophy, neuropathy, or progressive degeneration of the pharyngeal plexus secondary to Amyotrophic Lateral Sclerosis, Parkinson’s disease, Mobius syndrome, or Trisomy 21 syndrome.[7][8][9] VPD can result if the muscles of the head and neck are involved, especially the VP musculature. Myasthenia Gravis is an autoimmune disease that causes atrophy of skeletal muscles by targeting the acetylcholine receptor involved in neuromuscular signal transmission. Functions such as swallowing, phonation, and gaze fixation are impaired with resulting hoarseness, diplopia, dysphonia, eyelid ptosis, and poor head stabilization. Cerebral palsy may be associated with hypotonia and gross motor weakness.[3]
  3. Developmental/faulty learning: Poor pronunciation, articulation, or dialectical influences can be learned and emulated by children and masquerade as VPD. VPD may also arise from compensatory mechanisms after cleft palate repair. This includes greater use of nasal sounds (n, m, ng), glides (w, j), voiceless stops (p, t, k), voiceless fricatives (f, s), facial grimacing, and fewer plosives.[10] Differentiating between VPD and articulation disorders is challenging, and best done by a speech-language pathologist who is experienced in cleft speech abnormalities. Faulty learning is best corrected by speech therapy rather than surgery.
  4. Pediatric syndromes: VPD may exist as an associated symptom for many syndromes including Trisomy 21, Klippel-Feil, epidermal nevus syndrome, Turner syndrome, and VATER.[11] Velocardiofacial syndrome (VCFS) or 22q11 Deletion Syndrome is one of the most common syndromic causes of VPD in noncleft patients and affects 1:2000 to 1:4000 of newborns.[12][13] Anomalous neural crest migration disrupts the development of the pharyngeal arches.[14][15] These patients present with dysmorphic facies, conotruncal cardiac defects, hypocalcemic hypoparathyroidism, T-cell mediated immune deficiency, and variable neuromuscular weakness of the palatal and pharyngeal muscles. They may also have structural palate deformities such as reduced muscular volume, submucous cleft palate, and complete cleft palate.[16] The disorder may arise sporadically or in an autosomal dominant fashion. Approximately 27% to 92% of VCFS children have VPD, speech delay, feeding problems, and speech/language delay.[3][15]

Epidemiology

An overt cleft palate occurs in approximately 1 in 650 to 750 children born annually and is the most common cause of VPD.[3] Following primary cleft palate surgery, a deficiency persists in up to 20% to 30% of patients.[17] VPD can also be a complication after oral surgery. The incidence of VPD after adenoidectomy ranges from 1 in 1,500 to 1 in 10,000.[18][19] Postoperative palatal fistula and VPD occurs after primary cleft palate repair at a rate of 3.4% to 15%.[20][21]

The most common diagnosis in patients with VPD of unknown cause is 22q11.2 deletion syndrome.[22] The frequency of 22q11 deletion syndrome ranges from 1 in 2000 to 4000 [12][13], with 27% to 92% of diagnosed children having VPD.[15]

Pathophysiology

The velopharyngeal sphincter consists of the soft palate (velum), levator veli palatini, tensor veli palatini, palatopharyngeus, palatoglossus, muscularis uvulae, and the superior constrictor muscles.[3] During normal velopharyngeal closure, the levator veli palatini contracts the velum posterior-superiorly while the lateral pharyngeal walls and posterior pharyngeal wall contract medially and anteriorly, respectively. This serves to close the velopharyngeal port and separate the nasal and oral cavities during speech, swallow, vomiting, blowing, and sucking.

During normal speech, this separation allows airflow to be channeled from the vocal cords to the articulating tongue, lips, and teeth of the oral cavity. This produces the consonant (p, b, t, d, k, g, f, v, s, z, sh, ch, ge, l, r, w, y) and vowel sounds or phonemes.[23] A phoneme is the smallest unit of sound that distinguishes one word from another (ie. the t in “bat” vs. “bag”). Furthermore, air pressure needs to build up in the oral cavity up to 5 to 7 mm Hg in order to produce oral plosives, fricatives, and affricatives.[3] Plosives are consonant sounds created when air is stopped completely in the oral cavity and then suddenly explodes with its release such as the “p” sound. Fricatives are consonant sounds that are created by narrowing the airflow such as the “s” sound. Affricatives are plosives followed by a fricative such as the “ch” sound. Phonemes can be divided in voiced versus voiceless depending on if the vocal cords also resonate. The soft palate is relaxed and the nasal and oral cavities coupled only for three nasal consonants sounds in the English language (m, n, ng).[24][23] Partition of the two cavities also prevents nasal regurgitation of liquids and solids during swallow and provides an adequate negative pressure in the oral cavity during sucking.

During VPD, there is an airflow leak into the nasal cavity secondary to anatomic, neurologic, or functional impairment. Sound produced at the vocal cords subsequently enters both the oral and nasal cavities, causing both cavities to resonate and creates an overall “nasal” sound due to excessive nasal airflow. This is also known as nasal emission or nasal escape.[3][23] In severe cases, a small stricture in the nasopharynx can create a distinct, fricative sound, termed nasal turbulence.[23]

Patients’ ability to produce consonant sounds becomes impaired and they may develop maladaptive compensatory mechanisms such as glottal stops, pharyngeal fricatives, and facial grimaces in an effort to close the anterior nares and decrease nasal airflow.[4][25] Those with mild VPD may compensate for decreased oral air pressure by increasing overall laryngeal airflow and shouting to produce normal speech volume. This may eventually lead to voice hoarseness and vocal cord nodules. VPD results in decreased speech intelligibility and significant functional and social impairment.[4]

History and Physical

A detailed history should include any diagnosed syndromes, history of cleft palate, history of recurrent ear infections, neurologic abnormalities, prior surgical intervention within the oral cavity or pharynx, episodes of nasal regurgitation during eating, and risk for obstructive sleep apnea.[3][24] 

The physical examination should focus on the oral and nasal cavities with attention to the soft palate height, mobility, and symmetry, tonsil size, tongue mobility and symmetry, oral competence, nasal mucosa, nasal turbinates, and septum. Inspection for any anatomical abnormalities such as a submucosal cleft palate, bifid uvula, zona pellucida, posterior palatal notching, or neuromuscular weakness and asymmetry is recommended. Mobility of the soft palate is inspected by asking the patient to maintain a sustained phonation of the vowel sounds “e” or “i”. The clinician should also perform an otoscopic exam to assess for otitis media with effusion or tympanic membrane retraction, as VPD can be associated with Eustachian tube dysfunction.[3][24]

Evaluation

The diagnosis of VPD is obtained through history, physical exam, assessment of speech production, imaging, and instrumental evaluation.   

  1. Instrumental assessment provides a visual complement to perceptual speech analysis and is performed with either video-nasal endoscopy or multi-view videofluoroscopy by an interdisciplinary team of otolaryngologists, speech pathologists, and radiologists.
  2. Perceptual speech analysis is the gold standard for VPD diagnosis and is performed by a speech-language pathologist (SLP). Patients are asked to produce plosive, fricative, and affricative sounds and assessed for any hypernasal speech, compensatory facial grimacing, or misarticulation. Common phrases include “pet the puppies” and “Kathy kissed the cat”. Patients can also be asked to count from 60 to 80. A dental mirror can be placed under the nostrils to visualize any nasal air emission through fogging of the mirror.[3][26]
    • Video-nasal endoscopy uses a pediatric flexible laryngoscope to directly visualize the nasal passages, nasopharynx, adenoids, and soft palate. Live images are displayed on a video monitor for the speech pathologist who is performing the phonemic evaluation on the patient. The velopharyngeal sphincter is assessed during sucking through a straw, as well as during the production of plosives, fricatives, and affricatives. The location of VP closure, size of VP gap, and mobility of VP structures can be visualized and used to guide surgical decision-making. Nasal endoscopy can also diagnose an occult cleft palate, seen as a midline groove on the nasal surface of the soft palate, as the cause for a patient’s VPD.[3]
    • Multiview videofluoroscopy is commonly used in young children who may not tolerate a video-nasal endoscopy. Barium is given trans-nasally to coat the soft palate, lateral, and posterior pharyngeal walls. Serial images oriented in the lateral, frontal, and basal views are taken to assess VP closure during phonemic evaluation by the speech pathologist. The VP closure pattern is then classified as either coronal, sagittal, or circular (symmetric). Coronal closure involves only the posterior pharyngeal wall and soft palate. Sagittal closure involves only the lateral pharyngeal walls. Circular closure involves all structures equally.[3][24]
  3. Cephalometrics use serial X-rays from multiple views to study VP anatomic relationships during sustained speech. The anterior insertion of the levator veli palatini muscle into the soft palate is assessed, with more anterior insertion (seen in occult cleft palates) resulting in decreased soft tissue stretch and a VP gap during speech. Abnormalities in the cervical spine or skull base (platybasia) can contribute to nasopharyngeal disproportion. Cephalometrics is a quantifiable and reliable evaluation for treatment planning in children with velocardiofacial syndrome and isolated cleft palates.[3][27]
  4. Magnetic Resonance Imaging (MRI) can be used to assess levator veli palatine muscle size, insertion into the soft palate, and orientation for cases of suspected submucosal or occult clefts.[28] Advantages include non-invasiveness, high-quality imaging, and lack of radiation exposure. However, it is expensive and often requires sedation for young children.[3]
  5. Nasometry measures nasal emission and calculates a ratio between nasal and oral sound emissions (nasalance) using a sound separator placed between the nose and upper lip. The ratio is compared with normative values. Preoperative and postoperative nasalance can also be compared to determine surgery success. However, nasometry does not localize or quantify the VP gap. Large VP gaps can produce artificially low nasometric scores due to diminished high-pressure airflow.[3][24]

Treatment / Management

Treatment modalities for VPD include speech therapy, prosthetics, and surgery.[23]

  1. Speech therapy is the mainstay of treatment for patients with mislearned articulation as well as those with poor compensatory mechanisms from VPD. In addition, patients who undergo surgical intervention should continue speech therapy to further enhance their speech outcomes.[24]
  2. Oral prosthetics are custom-made by prosthodontists and anchored to the maxillary teeth to provide soft palate elevation. They are usually poorly tolerated by patients and often used as a temporary measure or for poor surgical candidates.[24] Prosthetics may also be utilized for patients with large palate fistulas after surgery, or as a temporary measure during a staged palate repair before completion of the second stage.
  3. Surgery is the definitive treatment for anatomic causes of VPD with the goal of creating a functional seal between the nasal and oral cavities while avoiding airway obstruction. Operative repair usually takes place after age 3-4 years when patients are cooperative with instrumental diagnosis.[3] Surgical interventions include palate muscle repositioning, pharyngeal flap, sphincter pharyngoplasty, and posterior pharyngeal wall augmentation.[3][4]
  • Palatal muscle repositioning maneuvers lengthen or readjust the orientation of palatal muscles. The Furlow double-opposing Z-plasty was originally used for primary cleft palate repair but has the added benefit of lengthening the palate by reorienting the levator veli palatini muscles in a transverse fashion.[29][30][31] It also has a lower risk of causing obstructive sleep apnea compared to the sphincter pharyngoplasty and pharyngeal flap.[32] Intravelar veloplasty involves re-aligning the levator veli palatini for cleft palate patients who did not undergo adequate muscle correction after their primary palate repair. The soft palate is opened along the midline with meticulous dissection and realignment of the abnormally inserted muscles.[4][20] Buccal myomucosal flaps raised from the inner aspect of the cheek have also allowed lengthening of the velum and retroposition of palate muscles.[33][34][35]
  • Pharyngeal flap is ideal for the sagittal closure pattern and involves elevating a midline, superiorly-based flap of mucosa and superior pharyngeal constrictor muscle from the posterior pharyngeal wall and suturing it to the posterior soft palate.[36][37] The flap narrows the nasopharyngeal inlet and creates two lateral ports for nasal airflow, which can be sealed by the bilateral medial movement of the lateral pharyngeal walls. The width of the midline flap is determined based on the VP gap, location of VP closure, and mobility of the lateral pharyngeal walls on pre-operative nasal endoscopy.[38][39] The pharyngeal flap is also effective in some patients who have neurogenic causes of VPD such as those with 22q11 deletion syndrome with poor palate movement. Because it involves the creation of a permanent bridge of tissue between the palate and the posterior pharyngeal wall, it is not as physiologic as some of the other options for closure.
  • Sphincter pharyngoplasty is ideal for the coronal closure pattern and involves elevating bilateral, superiorly-based flaps of palatopharyngeal mucosa and muscle. The flaps are rotated 90 degrees and the distal ends sutured to the contralateral posterior pharyngeal wall or to each other to create two horizontally overlapping arms.[40][41] This creates a smaller central port and a shorter transverse distance between the soft palate and posterior pharyngeal wall.[42]
  • Posterior pharyngeal wall augmentation involves expanding the posterior pharyngeal wall with a graft or alloplastic material in order to decrease the distance between itself and the soft palate. Several materials have been described such as cartilage, fascia, acellular dermis, calcium hydroxylapatite, hyaluronic acid, fat, and silicone.[1][24][43] This surgical approach is best suited for mild VPD with a small central gap and can be used to complement pharyngoplasties where a small gap persists.[4][24]

Differential Diagnosis

  • Faulty learning or dialectal influence. Children with no anatomical or neurological disorders may present with mild hypernasality secondary to mislearning or exaggerated regional dialects that emphases nasal characteristics.[10] Speech therapists should consider the native language and dialect of patients when performing perceptual speech analysis. In English, there is no distinction between nasal and oral vowel sounds, but distinctive nasal vowel sounds are common in many other languages including French, Portuguese, and Polish.
  • Speech Sound Disorder (SSD) is a broad speech impediment where patients are unable to correctly form sounds of certain words. Children will commonly try and substitute, omit, or change the sounds of certain phonemes, resulting in unintelligible speech. Although this is commonly seen in young children, most kids self-correct their speech by 4 years old. SSD can be divided into articulation disorders which involve a deficit in the motor production of sound, and phonologic disorders which are characterized by trouble learning the different speech sounds and recognizing their distinct meanings.[44] Treatment is with speech therapy if the child does not self-correct before school-age.
  • Childhood apraxia of speech (CAS) is a rare neurological condition that impedes a child’s ability to produce sound precisely and consistently. It involves a deficit in motor programming and planning and children are unable to express what they want to say into the necessary fine oral-motor movements. They have inconsistent errors in consonant and vowel production when repeating sentences.[45] These children need intensive and individualized treatment plans involving both an experienced speech-language pathologist as well as the child’s caregivers.
  • Tonsillar hypertrophy can restrict VP closure and cause VPD. Symptoms can be improved after tonsillectomy. Evaluation and treatment of tonsillar hypertrophy should occur prior to any surgical interventions for VPD, as pharyngoplasty in the setting of tonsillar hypertrophy can further obstruct the airway.[24]

Treatment Planning

Due to the varying etiological causes for VPD, a thorough evaluation must be first be performed. Patients with hypernasal speech secondary to faulty learning, phonologic disorder, or language impairment without anatomic or neurological deficits should be treated with speech therapy.

Instrumentation can assist in surgical planning by determining the location of the VP closure, size of VP gap, mobility of VP structures, and pattern of VP closure (coronal, sagittal, or circular) as well as an underlying occult cleft palate.[3] In patients with neurological deficits or those who are poor surgical candidates, evaluation by a prosthodontist for oral prosthetics is recommended.[24]

VPD secondary to anatomic abnormality is most commonly caused by a cleft palate. Delayed primary cleft palate repair after 18 months is associated with a higher incidence of speech impairment and VPD.[46][47] However, the timing of VPD surgery has not been shown to affect long-term speech outcomes. Pamplona et al showed that earlier surgical treatment of VPD did not affect postoperative speech therapy.[48] Studies have shown that the success of VPD surgery and speech therapy is influenced mainly by the quality of speech therapy as opposed to the timing of the surgery.[49] Thus, older patients should not be denied surgery with the belief that they might not benefit due to their age. Neither speech therapy nor surgery alone can resolve the poor articulation from VPD and patients often require a combination of speech therapy and surgical interventions.[23][49]

Prognosis

Several studies note a successful reduction in hypernasality with pharyngoplasty up to 85%.[50][51] Failure after VPD surgery can present in 4% to 12% of patients who may require additional or revision surgery.[3] Several studies did not find gender, age, palatal defects, prior adenoidectomy, or IQ, to be predictors of postoperative speech outcomes.[52][53][54][55][56]

In a systematic review for patients with 22q11 microdeletion syndrome and VPD, there was no significant difference in speech outcome or morbidity between the different types of pharyngeal flaps.[4] Rates of failures from primary pharyngeal flap and sphincter pharyngoplasty have been equal, with both techniques being amenable to salvage through revision surgery.[55]

Complications

Complications from surgical intervention involve obstruction of nasal airflow, hyponasal speech, persistent hypernasal speech, and obstructive sleep apnea (OSA). The pharyngeal flap has been associated with lateral port stenosis, hyponasal voice secondary to over-obturation of the nasopharynx, and postoperative OSA in up to 20% of patients.[3][57] Native mucosa should be used to cover any exposed muscle during flap elevation to prevent tissue contraction and suboptimal obturation of the VP port. An increased risk of postoperative OSA has been found with sphincter pharyngoplasty requiring flap revision.[58]

Risks of posterior pharyngeal wall augmentation include migration or extrusion of injected material, foreign body reaction, and fat embolism.[59] Persistent VP gap and hypernasal speech can be treated with a combined surgical approach using both sphincter pharyngoplasty and Furlow palatoplasty. This combination approach requires significantly less surgical revision compared to pharyngeal flap or sphincter pharyngoplasty alone.[60]

Postoperative and Rehabilitation Care

Postoperatively, patients are admitted overnight and monitored for oxygen desaturations, snoring, hyponasal speech, and OSA. They are discharged once tolerating adequate oral intake. Patients with concern for sleep apnea should undergo formal polysomnography to evaluate for OSA and be considered for continuous positive airway pressure in the short term. Persistent sleep apnea, airflow obstruction, and hyponasal speech may require flap revision or takedown in the long term.[3][55] Speech therapy should continue after surgical repair to enhance speech outcomes and address poor compensatory behaviors used by patients prior to surgery.

Consultations

Collaboration among the otolaryngologist, oral maxillary facial surgeon, plastic surgeon, speech-language pathologist, and the prosthodontist is essential for the diagnosis and treatment of velopharyngeal dysfunction. Close partnership with the cleft lip and palate team at hospitals is also beneficial due to the frequent association of VPD with cleft palate.[23]

The speech therapist is responsible for the perceptual analysis of speech production and interpretation of findings on nasal endoscopy and videofluoroscopy. A multidisciplinary review of endoscopic and radiographic images has been shown to increase the reliability of interpretations.[61]

Deterrence and Patient Education

Patient education on velopharyngeal dysfunction can be challenging due to the heterogeneous causes and need for multidisciplinary management. An early introduction to a speech-language pathologist is key for the diagnosis and alleviation of any inappropriate compensatory behaviors. Patients and their families should be counseled on the different methods of evaluation such as perceptual speech analysis, video nasal endoscopy, videofluoroscopy, and nasometry. Findings on testing and imaging should be shared and a discussion held regarding the best approach for treatment. Prior to any surgical intervention, patients and parents should be educated on the risks of surgery such as airway obstruction, sleep apnea, and need for additional surgical revisions.

Enhancing Healthcare Team Outcomes

Patients with velopharyngeal dysfunction should be managed by a multidisciplinary team of otolaryngologists, oral maxillary facial surgeons, plastic surgeons, neurologists, speech-language pathologists, prosthodontists, radiologists, primary care physicians, pediatricians, and geneticists. Early diagnosis and treatment of VPD are essential for long-term speech fluency and social function. Children with poor speech development and signs of VPD such as hypernasal speech and nasal regurgitation should be referred by their pediatricians to speech therapy for first-line treatment. A genetic workup should also be performed in collaboration with a geneticist.

Patients with associated neurological weakness should be evaluated by neurology. If anatomical abnormalities such as submucosal or occult cleft palate are diagnosed on instrumentation, a referral should be sent to an otolaryngologist or plastic surgeon specializing in velopharyngeal surgery. Speech therapy should continue even after surgical repair to enhance speech outcomes and address poor compensatory behaviors used by patients prior to surgery. Finally, patients may develop social anxiety and avoidance due to the intelligibility of their speech, especially in school and work settings. Formal peer support groups with parents and patients who share the diagnosis can aid patients in addressing their concerns.


References

[1] Belcher R,Deshpande A,Goudy S, State of the Art in Treating Velopharyngeal Dysfunction. Facial plastic surgery : FPS. 2016 Apr;     [PubMed PMID: 27097137]
[2] Trost-Cardamone JE, Coming to terms with VPI: a response to Loney and Bloem. The Cleft palate journal. 1989 Jan;     [PubMed PMID: 2645070]
[3] Ruda JM,Krakovitz P,Rose AS, A review of the evaluation and management of velopharyngeal insufficiency in children. Otolaryngologic clinics of North America. 2012 Jun;     [PubMed PMID: 22588042]
[4] de Blacam C,Smith S,Orr D, Surgery for Velopharyngeal Dysfunction: A Systematic Review of Interventions and Outcomes. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2018 Mar;     [PubMed PMID: 29437504]
[5] Kummer AW, Types and causes of velopharyngeal dysfunction. Seminars in speech and language. 2011 May;     [PubMed PMID: 21948641]
[6] Pickrell KL,Massengill R Jr,Quinn G,Brooks R,Robinson M, The effect of adenoidectomy on velopharyngeal competence in cleft palate patients. British journal of plastic surgery. 1976 Apr;     [PubMed PMID: 1276523]
[7] Hardy JC,Netsell R,Schweiger JW,Morris HL, Management of velopharyngeal dysfunction in cerebral palsy. The Journal of speech and hearing disorders. 1969 May;     [PubMed PMID: 5782400]
[8] Hillarp B,Ekberg O,Jacobsson S,Nylander G,Aberg M, Myotonic dystrophy revealed at videoradiography of deglutition and speech in adult patients with velopharyngeal insufficiency: presentation of four cases. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 1994 Mar;     [PubMed PMID: 8186219]
[9] Horton SK,Murdoch BE,Theodoros DG,Thompson EC, Motor speech impairment in a case of childhood basilar artery stroke: treatment directions derived from physiological and perceptual assessment. Pediatric rehabilitation. 1997 Jul-Sep;     [PubMed PMID: 9689252]
[10] Dworkin JP,Marunick MT,Krouse JH, Velopharyngeal dysfunction: speech characteristics, variable etiologies, evaluation techniques, and differential treatments. Language, speech, and hearing services in schools. 2004 Oct;     [PubMed PMID: 15609637]
[11] Goudy S,Ingraham C,Canady J, Noncleft velopharyngeal insufficiency: etiology and need for surgical treatment. International journal of otolaryngology. 2012;     [PubMed PMID: 22548069]
[12] Devriendt K,Fryns JP,Mortier G,van Thienen MN,Keymolen K, The annual incidence of DiGeorge/velocardiofacial syndrome. Journal of medical genetics. 1998 Sep;     [PubMed PMID: 9733045]
[13] Shprintzen RJ, Velo-cardio-facial syndrome: 30 Years of study. Developmental disabilities research reviews. 2008;     [PubMed PMID: 18636631]
[14] Duband JL,Escot S,Fournier-Thibault C, SDF1-CXCR4 signaling: A new player involved in DiGeorge/22q11-deletion syndrome. Rare diseases (Austin, Tex.). 2016;     [PubMed PMID: 27500073]
[15] Kobrynski LJ,Sullivan KE, Velocardiofacial syndrome, DiGeorge syndrome: the chromosome 22q11.2 deletion syndromes. Lancet (London, England). 2007 Oct 20;     [PubMed PMID: 17950858]
[16] McDonald-McGinn DM,Hain HS,Emanuel BS,Zackai EH, 22q11.2 Deletion Syndrome 1993;     [PubMed PMID: 20301696]
[17] Fisher DM,Sommerlad BC, Cleft lip, cleft palate, and velopharyngeal insufficiency. Plastic and reconstructive surgery. 2011 Oct;     [PubMed PMID: 21921748]
[18] GIBB AG, Hypernasality (rhinolalia aperta) following tonsil and adenoid removal. The Journal of laryngology and otology. 1958 Jun;     [PubMed PMID: 13564013]
[19] Skolnick ML, Velopharyngeal function in cleft palate. Clinics in plastic surgery. 1975 Apr;     [PubMed PMID: 1097159]
[20] Sommerlad BC,Mehendale FV,Birch MJ,Sell D,Hattee C,Harland K, Palate re-repair revisited. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2002 May;     [PubMed PMID: 12019005]
[21] Yang Y,Li Y,Wu Y,Gu Y,Yin H,Long H,Shi B,Zheng Q, Velopharyngeal function of patients with cleft palate after primary palatoplasty: relevance of sex, age, and cleft type. The Journal of craniofacial surgery. 2013 May;     [PubMed PMID: 23714912]
[22] Zori RT,Boyar FZ,Williams WN,Gray BA,Bent-Williams A,Stalker HJ,Rimer LA,Nackashi JA,Driscoll DJ,Rasmussen SA,Dixon-Wood V,Williams CA, Prevalence of 22q11 region deletions in patients with velopharyngeal insufficiency. American journal of medical genetics. 1998 Apr 28;     [PubMed PMID: 9557885]
[23] Sell D,Ma L, A model of practice for the management of velopharyngeal dysfunction. The British journal of oral     [PubMed PMID: 8909722]
[24] Glade RS,Deal R, Diagnosis and Management of Velopharyngeal Dysfunction. Oral and maxillofacial surgery clinics of North America. 2016 May;     [PubMed PMID: 27150305]
[25] Trost JE, Articulatory additions to the classical description of the speech of persons with cleft palate. The Cleft palate journal. 1981 Jul;     [PubMed PMID: 6941865]
[26] Rudnick EF,Sie KC, Velopharyngeal insufficiency: current concepts in diagnosis and management. Current opinion in otolaryngology     [PubMed PMID: 19005324]
[27] Veerapandiyan A,Blalock D,Ghosh S,Ip E,Barnes C,Shashi V, The role of cephalometry in assessing velopharyngeal dysfunction in velocardiofacial syndrome. The Laryngoscope. 2011 Apr;     [PubMed PMID: 21305558]
[28] Shprintzen RJ,Marrinan E, Velopharyngeal insufficiency: diagnosis and management. Current opinion in otolaryngology     [PubMed PMID: 19448542]
[29] Chen PK,Wu JT,Chen YR,Noordhoff MS, Correction of secondary velopharyngeal insufficiency in cleft palate patients with the Furlow palatoplasty. Plastic and reconstructive surgery. 1994 Dec;     [PubMed PMID: 7972481]
[30] Furlow LT Jr, Cleft palate repair by double opposing Z-plasty. Plastic and reconstructive surgery. 1986 Dec;     [PubMed PMID: 3786527]
[31] Hudson DA,Grobbelaar AO,Fernandes DB,Lentin R, Treatment of velopharyngeal incompetence by the Furlow Z-plasty. Annals of plastic surgery. 1995 Jan;     [PubMed PMID: 7702296]
[32] Liao YF,Noordhoff MS,Huang CS,Chen PK,Chen NH,Yun C,Chuang ML, Comparison of obstructive sleep apnea syndrome in children with cleft palate following Furlow palatoplasty or pharyngeal flap for velopharyngeal insufficiency. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2004 Mar;     [PubMed PMID: 14989690]
[33] Hens G,Sell D,Pinkstone M,Birch MJ,Hay N,Sommerlad BC,Kangesu L, Palate lengthening by buccinator myomucosal flaps for velopharyngeal insufficiency. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2013 Sep;     [PubMed PMID: 23237471]
[34] Hill C,Hayden C,Riaz M,Leonard AG, Buccinator sandwich pushback: a new technique for treatment of secondary velopharyngeal incompetence. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2004 May;     [PubMed PMID: 15151445]
[35] Mann RJ,Neaman KC,Armstrong SD,Ebner B,Bajnrauh R,Naum S, The double-opposing buccal flap procedure for palatal lengthening. Plastic and reconstructive surgery. 2011 Jun;     [PubMed PMID: 21617473]
[36] Honig CA, The treatment of velopharyngeal insufficiency after palatal repair. Archivum chirurgicum Neerlandicum. 1967;     [PubMed PMID: 4861153]
[37] Skoog T, The pharyngeal flap operation for cleft palate patients. Journal of the American Medical Women's Association. 1966 Dec;     [PubMed PMID: 4227207]
[38] Peat BG,Albery EH,Jones K,Pigott RW, Tailoring velopharyngeal surgery: the influence of etiology and type of operation. Plastic and reconstructive surgery. 1994 Apr;     [PubMed PMID: 8134487]
[39] Shprintzen RJ,Lewin ML,Croft CB,Daniller AI,Argamaso RV,Ship AG,Strauch B, A comprehensive study of pharyngeal flap surgery: tailor made flaps. The Cleft palate journal. 1979 Jan;     [PubMed PMID: 282029]
[40] Jackson IT, Sphincter pharyngoplasty. Clinics in plastic surgery. 1985 Oct;     [PubMed PMID: 3905177]
[41] Orticochea M, A review of 236 cleft palate patients treated with dynamic muscle sphincter. Plastic and reconstructive surgery. 1983 Feb;     [PubMed PMID: 6823477]
[42] Sloan GM, Posterior pharyngeal flap and sphincter pharyngoplasty: the state of the art. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2000 Mar;     [PubMed PMID: 10749049]
[43] Filip C,Matzen M,Aukner R,Moe M,Høgevold HE,Åbyholm F,Abrahamsen TG,Tønseth K, Superiorly based pharyngeal flap for treatment of velopharyngeal insufficiency in patients with 22q11.2 deletion syndrome. The Journal of craniofacial surgery. 2013 Mar;     [PubMed PMID: 23524725]
[44] Eadie P,Morgan A,Ukoumunne OC,Ttofari Eecen K,Wake M,Reilly S, Speech sound disorder at 4 years: prevalence, comorbidities, and predictors in a community cohort of children. Developmental medicine and child neurology. 2015 Jun;     [PubMed PMID: 25403868]
[45] Morgan AT,Murray E,Liégeois FJ, Interventions for childhood apraxia of speech. The Cochrane database of systematic reviews. 2018 May 30;     [PubMed PMID: 29845607]
[46] Randall P,LaRossa DD,Fakhraee SM,Cohen MA, Cleft palate closure at 3 to 7 months of age: a preliminary report. Plastic and reconstructive surgery. 1983 May;     [PubMed PMID: 6836060]
[47] Marrinan EM,LaBrie RA,Mulliken JB, Velopharyngeal function in nonsyndromic cleft palate: relevance of surgical technique, age at repair, and cleft type. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 1998 Mar;     [PubMed PMID: 9527305]
[48] Pamplona M,Ysunza A,Guerrero M,Mayer I,García-Velasco M, Surgical correction of velopharyngeal insufficiency with and without compensatory articulation. International journal of pediatric otorhinolaryngology. 1996 Jan;     [PubMed PMID: 8770673]
[49] Becker DB,Grames LM,Pilgram T,Kane AA,Marsh JL, The effect of timing of surgery for velopharyngeal dysfunction on speech. The Journal of craniofacial surgery. 2004 Sep;     [PubMed PMID: 15346022]
[50] Wagner RD,Wolfswinkel EM,Buchanan EP,Khechoyan DY, Surgical Outcomes for Speech Surgery in 22q11.2 Deletion Syndrome: The Dilemma of Persistent Velopharyngeal Insufficiency After Pharyngeal Flap Operation. The Journal of craniofacial surgery. 2017 Jul;     [PubMed PMID: 28582304]
[51] Rogers C,Konofaos P,Wallace RD, Superiorly Based Pharyngeal Flap for the Surgical Treatment of Velopharyngeal Insufficiency and Speech Outcomes. The Journal of craniofacial surgery. 2016 Oct;     [PubMed PMID: 27763974]
[52] Riski JE, Articulation skills and oral-nasal resonance in children with pharyngeal flaps. The Cleft palate journal. 1979 Oct;     [PubMed PMID: 290433]
[53] Losken A,Williams JK,Burstein FD,Malick D,Riski JE, An outcome evaluation of sphincter pharyngoplasty for the management of velopharyngeal insufficiency. Plastic and reconstructive surgery. 2003 Dec;     [PubMed PMID: 14663217]
[54] Perkins JA,Lewis CW,Gruss JS,Eblen LE,Sie KC, Furlow palatoplasty for management of velopharyngeal insufficiency: a prospective study of 148 consecutive patients. Plastic and reconstructive surgery. 2005 Jul;     [PubMed PMID: 15988249]
[55] Witt PD,Marsh JL,Marty-Grames L,Muntz HR, Revision of the failed sphincter pharyngoplasty: an outcome assessment. Plastic and reconstructive surgery. 1995 Jul;     [PubMed PMID: 7604092]
[56] Pryor LS,Lehman J,Parker MG,Schmidt A,Fox L,Murthy AS, Outcomes in pharyngoplasty: a 10-year experience. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. 2006 Mar;     [PubMed PMID: 16526928]
[57] Cole P,Banerji S,Hollier L,Stal S, Two hundred twenty-two consecutive pharyngeal flaps: an analysis of postoperative complications. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 2008 Apr;     [PubMed PMID: 18355599]
[58] Ettinger RE,Oppenheimer AJ,Lau D,Hassan F,Newman MH,Buchman SR,Kasten SJ, Obstructive sleep apnea after dynamic sphincter pharyngoplasty. The Journal of craniofacial surgery. 2012 Nov;     [PubMed PMID: 23154358]
[59] Crockett DJ,Goudy SL, Update on surgery for velopharyngeal dysfunction. Current opinion in otolaryngology     [PubMed PMID: 24874210]
[60] Bohm LA,Padgitt N,Tibesar RJ,Lander TA,Sidman JD, Outcomes of combined Furlow palatoplasty and sphincter pharyngoplasty for velopharyngeal insufficiency. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery. 2014 Feb;     [PubMed PMID: 24323907]
[61] D'Antonio LL,Marsh JL,Province MA,Muntz HR,Phillips CJ, Reliability of flexible fiberoptic nasopharyngoscopy for evaluation of velopharyngeal function in a clinical population. The Cleft palate journal. 1989 Jul;     [PubMed PMID: 2758674]