Velopharyngeal dysfunction in children with Prader-Willi syndrome after adenotonsillectomy

Prader-Willi syndrome (PWS) is a rare genetic disorder with an incidence rate of 1 in 10,000-30,000. Patients with PWS typically have symptoms related to hypotonia, obesity, and hypothalamic dysfunction. A high rate of obstructive sleep apnea (OSA) is found among this population of patients. Adenotonsillectomy has been advocated as a first line approach for treatment of OSA in patients with PWS. Velopharyngeal dysfunction (VPD) is a known complication of adenotonsillectomy. VPD can also be present in patients with global hypotonia, such as those with PWS. The objective of this study is to review the occurrence of VPD in patients with PWS after adenotonsillectomy for OSA.

A retrospective review was performed of all patients with PWS and OSA from a tertiary pediatric hospital between the years of 2002 and 2012. Pre- and post-operative sleep studies and sleep disordered breathing symptoms, post-operative VPD assessment by the speech-language pathologist (SLP), and VPD treatments were evaluated.

Eleven patients (five males and six females), fitting the inclusion criteria, were identified. The age of the patient at the initial otolaryngologic evaluation ranged from 2 to 9 years. All patients underwent adenotonsillectomy for sleep disordered breathing. Four patients were diagnosed with post-operative hypernasality after assessment by a speech-language pathologist. The hypernasality ranged from mild to moderately severe. Of the four patients with hypernasality, two were found to have structural issues requiring surgery (pharyngeal flap). Both of the surgical patients experienced significant improvement in their VPD after surgery. The remaining two patients were found to have articulation error patterns that were considered more developmental in nature and both responded to speech therapy. All patients, except one, had improvement in their polysomnogram or sleep symptoms after adenotonsillectomy. However, three patients continue to require continuous positive airway pressure at night.

Velopharyngeal dysfunction may occur after adenotonsillectomy in patients with Prader-Willi Syndrome. Families should be counseled of this risk and the potential need for operative intervention to correct it.