|Year : 2017 | Volume
| Issue : 2 | Page : 120-124
Velopharyngeal dysfunction of neurogenic origin: Evaluating the use of gel implant injection augmentation
Khurram Khan1, Michael Cadier2
1 West Midlands Regional Centre for Cleft Lip and Palate, Birmingham Children's Hospital, Birmingham, England
2 Spires Cleft Centre, Salisbury District Hospital, Salisbury, England
|Date of Web Publication||11-Aug-2017|
West Midlands Regional Centre for Cleft Lip and Palate, Birmingham Children's Hospital, Steelhouse Lane, Birmingham
Source of Support: None, Conflict of Interest: None
Objectives: Velopharyngeal dysfunction (VPD) secondary to neuromuscular pathology is well recognized. Surgical treatment in these patients using palatoplasty or conventional sphincteric and posterior flap-based pharyngoplasty is often contraindicated as they may further weaken or aggravate already impaired musculature. We report a small case series of patients who underwent successful long-term treatment for VPD of neurogenic origin using an injectable gel polymer to augment the posterior pharyngeal wall. Design: Three patients in whom a neuromuscular condition had led to the development of VPD underwent augmentation pharyngoplasty. Speech was compared pre- and post-operatively examining hypernasality, nasal emission, and nasalance scores and patient self-evaluation of outcome. Results: All three patients had improvement in parameters measured following pharyngeal injection augmentation. One patient noticed deterioration in speech intelligibility following initial injection into the velum: the implant polymer was easily removed and later reinjected in the posterior pharynx with good effect. Conclusions: The use of gel polymer injection pharyngoplasty in the treatment of neurogenic VPD was safe, simple, well tolerated, and easily reversible. However, due to recent severe complications reported from fat augmentation pharyngoplasty, we would not recommend its routine usage.
Keywords: Augmentation pharyngoplasty, velopharyngeal dysfunction, velopharyngeal incompetence
|How to cite this article:|
Khan K, Cadier M. Velopharyngeal dysfunction of neurogenic origin: Evaluating the use of gel implant injection augmentation. J Cleft Lip Palate Craniofac Anomal 2017;4:120-4
|How to cite this URL:|
Khan K, Cadier M. Velopharyngeal dysfunction of neurogenic origin: Evaluating the use of gel implant injection augmentation. J Cleft Lip Palate Craniofac Anomal [serial online] 2017 [cited 2018 Mar 22];4:120-4. Available from: http://www.jclpca.org/text.asp?2017/4/2/120/212836
| Introduction|| |
Velopharyngeal incompetence (velopharyngeal dysfunction [VPD]) secondary to neuromuscular disorders is well recognized. Treatment usually focuses on speech therapy to correct sound production by adaptive techniques. Surgical treatment using palatoplasties or conventional sphincteric and posterior flap-based pharyngoplasty are frequently felt to be undesirable through concern that the surgery may either further weaken the already impaired nasopharyngeal musculature or aggravate coordination of muscular function which could adversely affect swallowing, thereby precipitating aspiration.
Thus, in the treatment of VPD of neurogenic origin alternative strategies have primarily focused on substances used to augment the posterior pharyngeal wall. Numerous prosthetic and autologous substances have been proposed, with their relative advantages and disadvantages the subject of much debate.,,,,,,, Denny et al. reported the use of autologous costal bone or cartilage implants to preselected sites in the posterior pharynx in a preliminary study of twenty children with VPD. After the ninth patient, costal bone was discontinued due to problems with infection and resorption, and in the subsequent cartilage implanted cohort 80% demonstrated overall speech improvement in the short-term only. Similar problems with resorption have been encountered using autologous fat injection augmentation, despite its advantage as a readily available tissue with low donor-site morbidity.,,, Nonautologous materials are manufactured in an injectable or implantable form, minimizing operating time as well as obviating the need for a donor site. However, despite reports of numerous synthetic substances used to augment the pharyngeal wall, including Teflon, collagen, porous polyethylene, calcium hydroxyapatite, and silicone,,,,,,, they have not been without associated risk. This has led Hallén et al. to comment “…in augmentative surgery there is an intensive search for new biocompatible substances that are easy to inject and have a lasting effect.” In a case series of 23 patients augmented with silastic implants (ages ranging between 4 and 31 years old), the authors reported a total of five complete or partial extrusions, and similarly in 26 patients with proplast implants, 4 extruded postoperatively. More recently, Ulkur et al. concluded porous polyethylene to be effective in correcting mild adult VPD in 7 of 10 patients at 6-month follow-up. In a large, retrospective 40-year review of 111 patients who underwent augmentation with a range of principally silicone or gortex implants placed in a surgically dissected pocket in the posterior pharyngeal space, Lypka et al. demonstrated normal or near normal speech in 64 (73%) of the 88 patients with full postoperative speech evaluations, and an implant removal or extrusion rate of 11.7%.
However, the exact choice of implantable material has proved problematic, as it must fulfill the criteria of being nonallergenic and resistant to both resorption and migration. The latter can be a particular problem in the posterior pharyngeal wall given the lack of density due to the midline split in muscle fibers extending from the skull base. It must be predictable, long lasting, reversible, and safe.
Bio-Alcamid® (Polymekon, Italy) is a biocompatible gel polymer that has been widely used in cosmetic and reconstructive surgery as a method of soft-tissue augmentation. It is a permanent soft-tissue filler composed of a matrix of alkylimide groups (4%) and nonpyrogenic water (96%), which upon implantation is covered by a thin (0.02 mm) isolating collagen film, which allows it to bind to host tissues preventing movement. It is purported to be nonallergenic, nontoxic, easily injectable, with no reported history of migration, and importantly has the potential to be removed. There is no record of its use in velopharyngeal or vocal fold augmentation, however, there is a preliminary study of its use to treat gastroesophageal reflux disease. We present a series of three patients who underwent successful long-term treatment for velopharyngeal incompetence of neurogenic origin using the implantable gel polymer Bio-Alcamid® to augment the posterior pharyngeal wall.
| Materials and Methods|| |
Three suitable patients with VPD were identified in whom a neuromuscular condition had led to the development of VPD, and in whom sphincteric and posterior flap pharyngoplasties were contraindicated as these procedures could interfere with an already disturbed swallowing mechanism. Appropriate Institutional Ethical Approval was obtained. Two of these patients had previously tried multiple palatal assist devices that were not well tolerated due to problems with suitable dentition. All patients demonstrated moderate to significant gapping of the velum and posterior pharynx on lateral videofluoroscopy. Ethical approval for the procedure was obtained. A total of 4–8 ml of Bio-Alcamid® was injected into varying locations in the velopharynx depending on individual pathology and anatomical requirement. All injections were performed under local anesthetic only.
Speech evaluation was reviewed using Great Ormond Street Speech Assessment (a comprehensive standardized assessment framework used by speech and language therapy in treating cleft palate and VPD in the UK), nasometry, and patient self-assessment.
A 60-year-old male was referred with a long-standing speech anomaly resulting from a head injury sustained 43 years previously. Speech assessment revealed mixed dysarthria and VPD leading to hypernasal resonance. Lateral videofluoroscopy demonstrated a persistent gap in the velopharynx. Following inadequate improvements after speech therapy, the patient underwent an augmentation pharyngoplasty with 5 ml of Bio-Alcamid® injected into the posterior pharyngeal space at adenoidal level. He was discharged home the same day and reported no side effects from treatment.
A 51-year-old male was referred after an extensive investigation by the neurologists with postviral induced palatal and posterior pharyngeal palsy resulting in significant nasality of speech rendering him relatively unintelligible. Imaging confirmed VPD with a persistent small gap in the velopharynx. After an extensive consultation, he underwent augmentation pharyngoplasty with a total of 8 ml Bio-Alcamid® into the posterior pharyngeal space at adenoidal level as previously described. He was discharged home the following day and reported only mild coryzal symptoms in the postoperative period.
A 45-year-old male was referred with unintelligible speech secondary to Balo's concentric sclerosis, initially diagnosed in 1992, a rare variant of multiple sclerosis. A resonance disorder was judged to be the primary source of poor intelligibility following specialist speech and language assessment. Dysarthria was the main presenting problem with occasional dysphagia during the episodes of relapse. Lateral video fluoroscopy demonstrated no structural anomalies and a usual pattern of closure on individual sounds, however, in connected speech demonstrated an increasingly inconsistent and incomplete closure that was clearly visible. A palatal lift device was initially employed but not tolerated by the patient due to discomfort and excess saliva production. With concerns regarding interfering with swallowing, it was felt that conventional sphincteric flap pharyngoplasties were contraindicated and an augmentation pharyngoplasty performed after consultation with the multidisciplinary cleft team. Initially, a soft palatal augmentation with injection of Bio-Alcamid® was undertaken in a technique similar to that of Klotz et al. The patient was discharged home on the same day reporting only mild discomfort in his throat. At routine follow-up at 8 weeks, it was rapidly apparent to the multidisciplinary team that speech had been aggravated by the procedure as assessed using all of the above tests. At 11 weeks postoperative, the implant polymer was therefore easily removed from both injection sites, and the patient discharged home on the same day. At a later date, the patient underwent a second injection this time in the posterior pharynx.
| Results|| |
The speech outcomes for each patient comparing pre- and post-operative hypernasality and nasal emission scores are presented in [Figure 1]. There was a range of severity of preoperative symptoms; however, all patients demonstrated some improvement following treatment with gel polymer injection to the posterior pharynx at 6 months follow-up assessment. As outlined earlier, Patient 3 underwent two injections. The first was into the soft palate that resulted in a worsening of his symptoms: the implant was therefore removed, and he underwent a second injection into the posterior pharynx that demonstrated a marked improvement in his symptoms.
|Figure 1: Pre- and post-operative speech assessment results using the Great Ormond Street Speech Assessment rating system of hypernasality and nasal emission (*Resonance not rateable postoperatively due to dysphonia). Note Patient 3 underwent two injections: first into the velum (which was removed due to exacerbation of symptoms) and secondly into the posterior pharynx|
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The pre- and post-operative nasalance scores and patient self-evaluation of outcome scores are presented in [Figure 2]. Patients 1 and 3 demonstrated an improvement in nasalance scores posttreatment. All patients reported a “Fair” or “Good” self-evaluation of improvement in symptoms, following gel polymer augmentation injection therapy to the posterior pharynx.
|Figure 2: Nasometry and patient self-evaluation of outcomes pre- and post-pharyngoplasty injection augmentation|
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Patient 2 developed sleep apnea postprocedure that required treatment with a continuous positive airways pressure (CPAP) device. At 6-month follow-up, the sleep apnea had resolved; however, the improvement in speech remained stable. There were no other significant complications.
| Discussion|| |
Augmentation pharyngoplasty using the gel polymer Bio-Alcamid® offers a relatively simple surgical alternative for the treatment of VPD of neurogenic origin. The gel polymer was easily implantable with minimal morbidity to the patient, and in one case, though unfortunately unable to produce to the intended effect, was nonetheless removed without difficulty and the effects reversed. However, in cases of potentially progressive neurological disease where the course and rate may be difficult to predict, it is essential to balance the patient's long-term prognosis with the risks of any surgical intervention. In addition, in demyelinating disease muscle strength is weak: injecting mass into a mechanism innervated by an impaired neurological system may carry higher risk than injecting into a less dynamic posterior pharyngeal wall.
In patient 3, all outcome measures confirmed that the gel polymer injection augmentation to the soft palate exacerbated the VPD. Lateral videofluoroscopy confirmed accurate bulking of the velum had occurred with no evidence of migration, however, there was noticeably reduced velar movement. Although it cannot be entirely discounted that this could be the result of rapid and spontaneous progression of the Balo's sclerosis with decreased innervation of the primary velar muscles, the patient's general neurological stability presurgically make this seem highly unlikely. A more plausible hypothesis may be that the gel polymer increased the weight and hence the length of the velum such that the already weakened and demyelinated primary velar muscles had insufficient strength and velocity to approximate closure. Nonetheless, once a consensus decision had been made that the VPD had worsened postinjection augmentation, a key advantage of the gel polymer Bio-Alcamid® over other previously described autologous and nonautologous pharyngeal augmentation methods is that it was safely and easily removed.
Postoperative airway obstruction and/or obstruction sleep apnea are recognized complications of velopharyngeal surgery. The risk has generally been of greater frequency and severity following pharyngeal flap surgery and pharyngoplasty,,, than with pharyngeal augmentation surgery., In this study, the sleep apnea that developed postprocedure in one patient was rated as being of mild severity after respiratory assessment. The principal consequence was noisy breathing at night that was a problem for his partner and hence requested a CPAP device. However, due to significant improvement in the primary problem with his speech, the patient and his partner viewed this complication as minor and felt that the speech benefits exceeded the disadvantage of needing nightly CPAP for 6 months.
Injection pharyngoplasty with the gel polymer Bio-Alcamid® has been simple and safe to use and remove, is well tolerated with minimal morbidity to the patient, and has had significant improvement in treating VPD of neurogenic origin. However, since this study was carried out in 2010, the senior author has currently discontinued the use of this technique following reports of a severe embolic complication from fat injection into the posterior pharynx. In the UK, this has precipitated a self-enforced moratorium on the use of augmentation pharyngoplasty by injection, though the technique is still used outside the UK. In addition, the use of permanent soft-tissue fillers in the cosmetic industry have been associated with problems of granuloma formation and have largely been abandoned in the UK,,,, despite in noncosmetic regions such fillers having been used very successfully. Refinement of the injection technique may well lead to resumption of this procedure, however, at the current time, we would no longer recommend the routine use of injection pharyngoplasty for neurogenic VPD, despite the promising initial results we report.
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Conflicts of interest
There are no conflicts of interest.
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