Chapter 31: Velopharyngeal Dysfunction

Velopharyngeal dysfunction occurs in any situation in which air passes inappropriately through the nasal airway during speech. The causes can be categorized as cleft related or noncleft related. Situations which are not cleft dysfunction can specifically occur when closure of the velum against the nasopharyngeal walls is incomplete. Normal velopharyngeal function involves composite movements of the velum posterosuperiorly, posterior pharyngeal wall ventrally, and the lateral pharyngeal wall medially. Dysfunction can be caused by a short or immobile velum or a large nasopharynx with poor function. It leads to poor speech quality and nasal regurgitation of food and is seen in patients following cleft palate repair and LeFort I/II midface advancement. Other patients at risk of velopharyngeal dysfunction are those with a relatively large nasopharynx. Normal closure patterns of the velopharyngeal sphincter are classified as coronal, sagittal, circular, or bow tie. Any of these patterns can be involved in dysfunction of the sphincter, but a bow tie is not the most common (Fig. 31.1).1–3 Fig. 31.1 Bird’s-eye view of the velopharynx illustrating directional movements of the representative closure. (From Bentz ML, Bauer BS, Zuker RM. Principles & Practice of Pediatric Plastic Surgery. St Louis: Quality Medical Publishing, 2007.) Coronal Sagittal Circular Bow tie Circular with Passavant’s ridge

Velopharyngeal dysfunction is a general descriptive term to describe any abnormal velopharyngeal function regardless of the cause. A more accurate description for a neuromotor control problem is velopharyngeal incompetence. In contrast, velopharyngeal insufficiency describes a structural abnormality resulting in dysfunction. Velopharyngeal dysfunction can result from a learned response that is neither structural nor neuromotor and this is termed velopharyngeal mislearning. Velopharyngeal disproportion describes a situation where the velum is small relative to the nasopharyngeal space as may be seen in patients with velocardiofacial syndrome.1,2

3. Kummer AW, Marshall JL, Wilson MM. Non-cleft causes of velopharyngeal dysfunction: implications for treatment. Int J Pediatr Otorhinolaryngol 2015;79(3):286–295

Consonants may be categorized as plosives, fricatives, or affricates. Plosives include b, t, d, and k. Fricatives include f, v, s, z, sh, and th. Affricates include ch and j. During formation of these sounds, nasal emissions may be evident if closure of the nasopharynx is incomplete. When using plosives such as p, b, or t, there needs to be initial occlusion of the vocal tract by the lips or tongue such that airflow stops and pressure builds. Sudden release of the occlusion then produces the sound. Fricatives such as f and v require air being forced through a narrow channel made by placing two articulators such as the lower lip against the teeth. Sibilants are a subset of fricatives in which the tongue directs air over the edge of the teeth, resulting in high pitch sounds such as s or sh. Affricates such as ch represent sounds that start as a plosive and continue as a fricative.1–6

5. McWilliams BJ, Morris H, Shelton R. Cleft Palate Speech. Philadelphia: BC Decker; 1990

6. Bernthal JE, Bankson NW. Articulation and Phonological Disorders. Englewood Cliffs: Prentice Hall; 1988

Instrumental assessment of velopharyngeal dysfunction is directed at identification of the cause and severity of the speech problem. Multiview videofluorscopy is a useful modality for semiquantitatively assessing both the type and extent of velopharyngeal closure. It involves static and dynamic frontal and lateral views of the velopharynx. It can be performed at an early age (usually from age 2 onward) and avoids the need for an invasive approach. Nasometry is performed from age 3 onward and involves placement of air pressure transducers inside the nostril and mouth. This enables measurement of oral and nasal air pressure, nasal airflow, and also facilitates calculation of the velopharyngeal port size. Nasoendoscopy can be performed from age 4 onward and allows qualitative assessment of velopharyngeal closure patterns and port size. MRI is used as an adjunct to velopharyngeal dysfunction and provides only static rather than dynamic views. Perceptual speech evaluation is not an instrumented assessment. It is undertaken by the speech and language therapist. Both spontaneous speech and provocative speech samples are assessed.1–3

Some authorities propose an algorithmic approach to the surgical management of velopharyngeal dysfunction. This is dependent on the location and size of the velopharyngeal port closure deficiency: • Small to moderate gap and anterior midpalate velar musculature—re-repair palate and retroposition muscle (straight line or Furlow) • Small to moderate gap and posterior velar musculature—consider palatal lengthening with buccal myomucosal flaps or pharyngoplasty (for touch closure—consider velar fat grafting or re-repair of palate) • Large gap and short but highly mobile palate—consider palatal lengthening with buccal myomucosal flaps • Large gap and coronal closure pattern—consider pharyngoplasty • Large gap and noncoronal closure pattern—pharyngeal flap However, a recent meta-analysis refutes the effectiveness of this theoretical approach and suggests that a pharyngeal flap is the superior choice in most cases.1–3

Posterior wall augmentation creates a static posterior obstruction and can be achieved using injectable substances such as fat, collagen, or Teflon. Although it is quick and relatively simple, it is less effective than other surgical techniques and there is a risk of migration, extrusion, or embolization of the injected material. This is of particular concern where the internal carotid arteries are medialized and lie just deep to the posterior pharyngeal wall as can occur in velocardiofacial syndrome. It can also result in obstructive sleep apnoea.1,2

The Hynes and Orticochea procedures are both types of sphincter pharyngoplasty. Although they are based on the same principle of raising pharyngeal wall flaps to create a sphincter at the velopharyngeal port, they differ in a number of ways. The Hynes technique involves bilateral superiorly based salpingopharyngeus musculomucosal flaps whereas the Orticochea technique involves bilateral superiorly based palatopharyngeus musculomucosal flaps. In addition, the Orticochea technique utilizes a third, inferiorly based, posterior pharyngeal wall flap. The flaps from the Orticochea technique are attached in an overlapped fashion to the posterior pharyngeal wall and covered by the third flap. Neither technique involves Z-plasties.1,2

Surgical procedures to treat velopharyngeal dysfunction can be categorized as either obstructive or nonobstructive. Obstructive techniques include the pharyngeal flap and pharyngoplasty. Nonobstructive techniques include the double opposing Z-plasty, straight line palate repair, palatal lengthening using buccal flaps, velar fat grafting, and posterior pharyngeal wall augmentation. Pharyngeal flap surgery involves raising a flap of mucosa and pharyngeal constrictor from the posterior pharyngeal wall and insetting this into the soft palate. This results in a permanent tissue bridge from the velum to the posterior pharyngeal wall and nasal airflow is achieved through the created two lateral ports. Velopharyngeal function is achieved by movement of the lateral pharyngeal walls medially to close the ports. The flap may be either superiorly or inferiorly based and varied in terms of size and inset (Fig. 31.2).1–5 Fig. 31.2 Sphincter pharyngoplasty. A, A catheter is passed transnasally and attached to the uvula. B, Proposed incisions (dashed lines) are shown. C, Both tonsillar pillar flaps are elevated. D, Palatopharyngeal fl aps are rotated through 90 degrees. They are ready for attachment to the posterior pharyngeal wall. E, Completed sphincter pharyngoplasty. The flaps are overlapped and sutured to each other and to the posterior pharyngeal wall. (From Bentz ML, Bauer BS, Zuker RM. Principles & Practice of Pediatric Plastic Surgery. St Louis: Quality Medical Publishing, 2007.) Catheter A B C E D Retractor Endotracheal tube

The most significant complication following velopharyngeal surgery is airway obstruction and this occurs in approximately 10% of patients. Approximately 1% will require reintubation. The risk will be affected by other factors such as mandibular size, age at surgery, and respiratory function. Therefore, airway monitoring is vital in all postoperative patients undergoing velopharyngeal surgery. However, Pierre Robin patients are particularly at risk because the sequence includes the triad of micrognathia/retrognathia, glossoptosis, and airway obstruction that can be exacerbated by speech surgery. Adenoidectomy can exacerbate velopharyngeal dysfunction (VPD), as it can increase the physical distance required to achieve velopharyngeal (VP) closure during speech. Velocardiofacial syndrome may be associated with VPD in conjunction with abnormal facies and cardiovascular abnormalities. Stickler syndrome often involves cleft palate in conjunction with a collagen gene mutation, leading to ocular malformations, hearing loss, and arthropathies. VPD may also be present. These conditions do not specifically predispose to airway issues.1–5

The most common early complication following velopharyngeal surgery is obstructive sleep apnea and this can occur in as many as 90% of cases during the first 1–2 days. It usually resolves spontaneously as postoperative edema decreases and is managed conservatively. However, in some circumstances (less than 1%) intubation is required in the short term. Either way, it is vital to discuss this preoperatively as the effects can be life threatening and even if not, it can be alarming for the family to observe. Other potential complications include intraoperative and postoperative bleeding, wound dehiscence, and failure to significantly improve speech. Life-threatening bleeds can occur when injury to the internal carotid artery occurs. This is a risk when the vessel is placed aberrantly toward the midline as occurs in certain conditions such as velocardiofacial syndrome. Swallowing problems are unlikely following velopharyngeal surgery. General complications such as chest infection are also unlikely in most cases.1–4