PMY Tang, BSY Tsui, NSY Chao, EKW Chan, KH Lee

Abstract

Velopharyngeal dysfunction (VPD) refers to the inadequate separation of the oral and nasal cavities during speech and/or swallowing. In children, it is often caused by structural and/or functional palate abnormalities. Children with surgically repaired congenital cleft palate are at risk of having residual VPD. We retrospectively review children with VPD at the Hong Kong Children's Hospital from 2020 to 2023. Twenty children suffered from VPD, 12 had history of congenital cleft palate with surgical repair in childhood, 8 had congenitally intact palates with genetically confirmed 22q11.2 microdeletion. Out of these 20 children, 2 declined surgical intervention, 13 opted for pharyngeal flap operation and 5 opted for Furlow palatoplasty. For those who opted for VPD corrective operations, all but one reported significantly reduced hypernasality post operatively. Our review suggests that regardless of the etiologies of their VPD, most children are able to achieve satisfactory speech after their VPD corrective surgeries.

Introduction

Velopharyngeal dysfunction (VPD) refers to the inadequate separation of the oral and nasal cavities during speech and/or swallowing. In children, it is often caused by structural and/or functional abnormalities of the soft palate and the pharyngeal muscles, resulting in social, emotion and educational difficulties.¹ The most common cause of VPD in children would often be residual velopharyngeal dysfunction after primary cleft palate repair. Clinically, these patients usually presented with hypernasal speech, increased nasal resonance and nasal turbulence with compensatory speech errors. In children, perceptive speech assessment by a speech pathologist would be the gold standard in the diagnosis of VPD, as instrumental assessment was often poorly tolerated in this population.

Since the establishment of the Hong Kong Children's Hospital in 2019, a multidisciplinary cleft clinic was set up, where surgeons could assess the patient together with a speech pathologist simultaneously in the clinic, allowing close collaboration in managing children with velopharyngeal dysfunction. The use of fluorescence in situ hybridisation (FISH) in the detection of 22q11.2 microdeletion (22qDS), which is a genetic condition most commonly associated with velopharyngeal dysfunction, has also become available to surgeons at the cleft clinic since 2020. In view of the wide spectrum of variable clinical presentation of 22q11.2 microdeletion, the true incidence of the genetic condition in Hong Kong remains unknown, and the prevalence of such syndrome occurring in children with VPD has not been reported. While we did not have specific guidelines in ordering the genetic test, balancing resource allocation and cost effectiveness, we often would only consider genetic testing when there was high clinical suspicion, such as for patients presenting with VPD and intact palates.

With such heterogenous clinical presentations and etiologies of children presenting with velopharyngeal dysfunction, it is not surprising that there is currently no well established treatment protocol in the optimal management of their speech conditions, and local data on children with VPD is lacking. We aim to review the clinical presentation and surgical outcomes of children presenting with VPD at the multidisciplinary cleft clinic in the Hong Kong Children's hospital.

Methods

A retrospective study was conducted of patients presenting with VPD to the cleft clinic in the Hong Kong Children's Hospital from 2020 to 2023. All VPD were clinically diagnosed by perceptive speech assessment by a speech pathologist. The clinical records of these patients were reviewed, data including gender, medical history, age at VPD - corrective surgery (if performed), post-operative speech outcome and co-morbidities were analysed. Any genetic diagnosis of 22qDS, if the genetic test had been performed, was also reviewed.

Results

A total of 20 patients suffering from velopharyngeal dysfunction were identified.

Twelve patients were born with cleft palate and had their primary cleft palate repair operations in their childhoods. Their gender, type of congenital cleft anomaly, type of primary palatoplasty, age of undergoing VPD - corrective surgery and the type of VPD - corrective surgery were shown in Table 1. These patients were diagnosed to have VPD during their regular clinical follow up at the cleft clinic. For their VPD - corrective surgeries, 9 of them had superiorly based pharyngeal flap operation, and 3 of them had revision Furlow palatoplasty. All but one reported significant reduction of hypernasality after their VPD - corrective operation. The one patient who had residual hypernasality after the revision Furlow palatoplasty had history of cleft palate with primary von Langenbeck repair. In view of her unexpected persistent VPD, a genetic test was offered, and she was confirmed to have 22qDS. She is currently considering further VPD - corrective surgery.

Eight patients had intact palates and presented with VPD. Genetic testing was offered to all of these patients and all of them were genetically confirmed to be suffering from 22qDS. Their gender, age of undergoing VPD - corrective surgeries (if performed), type of VPD - corrective operations and co-morbidities were shown in Table 2. For their VPD - corrective surgery, 4 underwent pharyngeal flap operation, 2 underwent primary Furlow palatoplasty and 2 declined surgical intervention. For patients who had opted for VPD - corrective surgeries, all had significant reduction in hypernasality. There were no peri-operative blood transfusion and no surgical mortality.

Discussion

While not all patients suffering from VPD would opt for surgical intervention, for those who opted for operation, all except one had reported significantly reduced hypernasality after the operation, regardless of the cause of their VPD and the type of VPD - corrective surgery they received. In patients presenting with VPD, the decision for VPD - corrective surgery and the timing of the operation would often depend on the patient's perception of their speech function. For the two patients who declined VPD - corrective surgery, both had significant cognitive impairment, which might potentially implicate on their decision on VPD - corrective operation.

In patients who had not been tested for 22qDS, all of them had history of congenital cleft palates that had been surgically repaired in childhood. The clinical history of congenital anatomical anomaly was suggestive of a potential structural cause of their VPD, which was evident by the relatively short velums at clinical examinations. As genetic screening tests were not routinely performed in VPD patients with known congenital cleft palate, we were unable to conclude the incidence of 22qDS in this population. Although VPD could have various different clinical presentation, such as compensatory mis-articulation, audible nasal emission and facial grimace, we chose to single out hypernasality as the outcome measure after VPD corrective operation as it was often the very first speech parameter that would be improved significantly without much speech therapy or training after the operation, and it was often independent on the patient's cognitive level.

Based on the US census 2010, 22qDS was estimated to have a prevalence of 1 in 2000 - 6000 live births² and the majority (90 - 95%) of the newly identified patients with 22qDS are found to have de novo deletions where neither parent has or is affected.³ Although 22qDS is a common genetic condition, due to the variability of its clinical presentation, lack of recognition by clinicians and the of lack of accessibility to the genetic testing methods, the diagnosis is often delayed, if not at all missed. Historically, various conditions such as DiGeroge syndrome, conotruncal anomaly face syndrome, velocardiofacial syndrome, Cayler Cardiofacial syndrome and autosomal dominant Opitz G/BBB syndrome have been known to be associated with the 22qDS, and they were described clinically prior to the development of advanced cytogenetic studies. In the large paediatric cohort from the Children's Hospital of Philadelphia, the median age of 22qDS diagnosis was 360 day-old2 and of these patients, about 5% were referred for genetic investigations by the craniofacial specialists.⁴ The prevalence of 22qDS in the Chinese populations has not been well documented,⁵ although recent studies have shown that the condition is likely to be under diagnosed in the adult Chinese populations.⁶

The timely recognition of 22qDS in children presenting with velopharyngeal dysfunction is important as it carries significant implications on the surgical planning and expectation management of the speech outcome. Speech production skills have been shown to be worse in children with 22qDS than in children with isolated cleft palate.⁷ Literatures have shown that even after undergoing cleft palatal repair for overt or submucous cleft palate, patients with 22qDS are less likely to demonstrate speech correction, and secondary speech surgery is frequent required due to the additional abnormalities seen in these patients.⁸

In our centre, specific 22qDS genetic testing have only recently become easily available to the frontline cleft surgeons, and at no additional cost to the patients. Therefore, as a pilot preliminary measure, we were only offering 22qDS genetic testing when we have very strong clinical suspicions that such patients are carrying such genetic mutation, i.e. in patient with anatomically intact palate and significant VPD. Although we did not have sufficient data to conclude the incidence of 22qDS in patients presenting with VPD, we were surprised by our findings that 100% of all the patients with intact palates were subsequently confirmed to be carrying the 22qDS genetic mutation.

One exception was the patient with congenital cleft palate, repaired with von Langenbeck palatoplasty at 1-year-old, and revision Furlow palatoplasty at 9-year-old. As she was still having significant residual hypernasality, we decided to offer the genetic testing for 22qDS and it was confirmed to be positive. Retrospectively speaking, if we had known her genetic diagnosis before the revision Furlow palatoplasty, other surgical treatment option such as pharyngeal flap might have been considered when she was 9-year-old instead.

For patients with history of primary cleft palate repair in their childhoods, the established standard vigilant clinical monitoring of their speech profiles, and regular speech assessment sessions with the dedicated speech pathologist facilitated the timely diagnosis and intervention of their residual and persistent VPD. However, in patients with anatomical intact palate, the diagnosis of VPD often depends on the parents' awareness and timely referral. Thus, we believed with increased awareness of the clinical entity of VPD in the frontline clinicians and in the general population, an increase in the diagnosis of 22qDS would be expected.

The decision on the type of VPD - corrective surgery depends on the patient's age, cause of VPD, the palatal anatomy (attachment and orientation of the levator veli palatini muscles, size of the nasopharyngeal port), the presence of underlying genetic syndrome and the surgeon's experience. Currently, there is no common consensus on which surgical technique would be best suited for patients with 22qDS. We wish that with time, a registry of patients with 22qDS could be set up to facilitate long term monitoring of their speech profiles and continual evaluation of other potential co-morbidities associated with the syndrome. Moreover, a dedicated clinic with paediatrician would be ideal in the comprehensive management of patients with 22qDS.

Limitation

A significant limitation in our review is the lack of objective peri-operative speech evaluation to quantify the patient's VPD improvement. Instrumental assessment such as nano-endoscopy would allow the numerical calculation of the improvement in the velo-pharyngeal closing ratio, theoretically providing an objective outcome measure. Unfortunately, such invasive investigation is often poorly tolerated in children, especially in children with genetic mutation such as 22qDS. Therefore, we believed a validated and standardised perceptive speech assessment score would be the most appropriate tool in this clinical setting. And the mentioned speech assessment scoring system in Cantonese is currently undergoing development by our team of dedicated speech pathologists.

Conclusion

Our review suggested that a sizeable number of children are suffering from VPD in Hong Kong. Surgical intervention such as revision Furlow palatoplasty or pharyngeal flap operation were safe and effective in reducing the hypernasality in this group of children, regardless of the aetiologies of their VPD. Clinicians should have high index of suspicion when managing patients with VPD and anatomically intact palate, specific genetic testing for 22qDS should be considered to facilitate surgical planning and patients' expectation management. A longer term monitoring would be beneficial to evaluate patients' speech outcomes and for assessment of potential complications of the operations such as obstructive sleep apnea.

Figure 1 The types of VPD - corrective surgery received for patient with cleft palate.

Figure 2 The types of VPD - corrective surgery received for patients with intact palates.

Declaration of Interest

The authors declare no conflict of interest.

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