Chapter 59 Current techniques for the treatment of velopharyngeal insufficiency
Velopharyngeal insufficiency (VPI) is a significant speech disorder. This is usually identified and addressed in childhood, but may be seen as a consequence of central nervous system disease or injury, peripheral nerve injury or palate resection with cancer ablation in the adult. VPIcan be a result of inappropriate articulation and hence, in these cases, remediable by aggressive speech therapy. All too often the treatment will need to be surgical. In this chapter, the surgical treatment will be addressed. Prosthetic management can be quite useful as well and will be addressed in the patient selection section, but will not be fully described here.
Most children with VPI can be successfully treated by speech therapy. It is therefore imperative that the surgeon work closely with the speech pathologist in reduction of hypernasality, with appropriate phoneme production. In the case of VPI following CNS injury, the speech pathologist may be needed to address both swallowing as well as speech. Because recovery of function may take months, surgical intervention in these cases should proceed only after there seems to be a cessation of improvement in function.
The trained ear may hear the hypernasality, nasal emission and nasal turbulence in structured samples or spontaneous speech. The use of a non-heated mirror beneath the nose may give a reasonable assessment of the leakage of air through the nose during speech tasks. As /m,n,ng/ are normally nasalized sounds, the speech sample should focus on the other consonant non-nasal phonemes including/p,b,t,d,s,sh,z/. If the phoneme is not appropriately articulated it may be hypernasal. If possible the sample should obtain isolated phonemes, single words, phrases, sentences and spontaneous speech. Focus should be on the phonemes that are accurately articulated. The assessment of appropriate articulation is best done by the speech pathologist. This emphasizes the need for team care of the person with VPI. Surgical intervention should not be the order when speech therapy alone could suffice.
Another objective measure of hypernasality is naso-metry, also called nasalence testing. The procedure compares the energy coming from the nose versus the mouth in a structured speech environment. With a sample loaded with non-nasal phonemes, hypernasality will be documented as a higher number and is compared to an established normal. It is rated as the number of standard deviations from the mean. If the sample is well articulated and there is good co-operation, this can be a help in deciding the need for surgical intervention.
Occasionally it is felt that the patient needs aggressive intervention, but is not a surgical candidate. These situations include severe airway obstruction, progressive disease, and prior radiation therapy to the airway or medical problems that would reduce the advisability of surgery. In these cases prosthetic management should be considered. An adequately long palate can be lifted to allow velopharyngeal competence or an obturator placed behind the palate can be used. The obturator is especially useful if there is a soft tissue defect from a cancer ablation or if the palate is congenitally short and the palatal lift cannot allow complete closure.
The appliance is clasped to the teeth and may be used during the day, but is removed for cleaning and sleep. This is of special help for both adults and children with a risk of obstructive sleep apnea. Children with other craniofacial syndromes may be at special risk for airway obstruction and prosthetic management may be a good option for them. Endoscopy can help with the determination of the need for prosthesis, as well as its fitting.
Though some use only a single surgical procedure for all, there is wisdom in deciding the surgery based on the shape and the size of the ‘gap’ that needs obturation. A coronal or circular closure pattern may be more successful with sphincter pharyngoplasty than the sagittal closure pattern, as the area needing obturation may be more lateral. A pharyngeal flap that obturates the central velopharynx may be more helpful in these situations. If there is a small central gap, one should consider an augmentation.
If the levator veli palatini muscles are longitudinal in orientation rather than transverse, consideration must be given to either an intravelar veloplasty or a Furlow double opposing Z-plasty. In both of these operations the levator is reoriented to improve palatal motion, thereby correcting the VPI. The Furlow will be described in detail here.
Regardless of which surgical intervention is chosen, there is a potential effect on the airway. The Furlow lengthens and thickens the palate. All of the others to a greater degree reduce the cross-sectional airway areaat the velopharynx. This alteration unfortunately mayprecipitate immediate post-surgical airway obstructionand OSA or sleep-disordered breathing, also. In general it seems the procedures from least to most obstructive are: Furlow, augmentation, sphincter and pharyngeal flap. Of course, each of the latter three may be altered tosome extent to increase or decrease nasopharyngeal obturation and hence airway obstruction. This is based onthe degree of motion of the velopharynx during speech. Care must be taken in the decision for surgical interven-tion to offer informed consent with regard to the airway issues.
As one considers surgery for VPI, it is important to plan the procedure based on the endoscopic findings. As was discussed above, one should consider the Furlow for any submucous cleft palate, as one could hope the reorientation of the levator sling would allow improved closure. If there is substantial lateral wall motion, the pharyngeal flap is ideal as it allows obturation without as much airway risk as a wide flap. Sphincter pharyngoplasty works well for most situations, as most people will have a circular or coronal closure pattern and this obturates the lateral and posterior velopharynx.
The association of 22q11 microdeletions (velocardiofacial syndrome) with especially non-cleft VPI makes it imperative to consider cardiac disease in the population of children with VPI. Careful examination and clearance by pediatrics or cardiology are important. Additionally many children with this syndrome will have medialization of the great vessels. This is often seen endoscopically as a pulsatile area in the hypo- or velopharynx. Though usually one may be able to successfully and safely complete the speech surgery even in this setting, it is critical to know this is present and avoid injury to the vertebral or carotid artery. Not only should this be considered at endoscopy, but as the pharynx is inspected as the mouth gag is placed, one should always re-evaluate for pulsation.
The surgery is performed under general anesthesia. Usually the use of an oral RAE tube will allow less interference with the field. The Dingmann mouth gag is usually used. It has the advantage of self-retaining lateral retractors and springs to allow suture retention. Other mouth gags used in tonsil surgery can be employed as well. Craig Senders suggested that releasing the pressure on the tongue during the surgery allowed improved blood flow and likely decreased pain.1
Local infiltration of the flap areas is necessary for hemostasis and will decrease local pain to make the anesthesia smoother. Lidocaine with epinephrine is good, but has a relatively shorter duration of pain control.
A throat pack is suggested, especially if the endotracheal tube is non-cuffed. This will hopefully prevent both aspiration of blood around the endotracheal tube and also swallowing of blood that could increase the chance of postoperative nausea.
At the end of surgery, a tongue suture can be placed. This is tied loosely and the tail remains long. It is taped to the side of the mouth. In the event of postoperative airway obstruction, pulling the tongue anteriorly with the suture will improve the airway. This is usually removed the following morning if the airway is secure.
The Furlow double opposing Z-plasty is quickly becoming a standard way of repairing a cleft palate. The advantage is the reorientation of the levator. If the levators are longitudinal one must consider the Furlow, or completely dissecting the levators to perform an intravelar veloplasty. In this chapter the focus will be on the Furlow.
A Z-plasty lengthens a scar. In VPI the problem often includes a short palate. The double Z-plasty lengthens the palate. The initial ‘Z’ can be made in either direction but the right-handed surgeon seems to do better as pictured (Fig. 59.1A). The posteriorly based flaps are always the myomucosal flaps. The anteriorly based flaps are mucosa only. Kathy Sie suggests rounding the tips of the flaps to improve the vascular supply.2 The incision is carried through the oral cavity mucosa. As the incision is madein the left hemipalate, care must be taken to maintain a small amount of mucosa behind the posterior edge of the hard palate so that suturing is easier. Careful dissection through the levator and tensor veli palatini tendon brings one to the nasal mucosal layer. The plane is usually well defined. Meticulous blunt and sharp dissection separates the undersurface of the muscle bundle from the nasal mucosa.
Fig. 59.1 Furlow. A, The dashed line indicates the location of the incisions for the initial Z-plasty. The dotted line describes the posterior border of the hard palate. Flap (A) is the oral cavity myomucosal flap and flap (B) is the mucosal flap. B, The posteriorly based myomucosal flap (A) has been elevated as has the anteriorly based mucosal flap (B). The dashed lines show the location for the incisions to create the nasal layer myomucosal flap (D) and the nasal mucosal flap (C). C, The flaps (C) and (D) have been rotated and sutured into position. The uvula is often divided at this point to grant more mobility to the flap (D). The flaps (A) and (B) are retracted out of the field to improve the access for suturing the nasal layer. D, The flaps (A) and (B) have been rotated to create the second Z-plasty. They have been sutured into position. The uvula has been closed. The dashed line shows the location of the closure of the nasal Z-plasty.
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