22q11.2 Deletion syndrome and obstructive sleep apnea

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Abstract

Otolaryngologic problems are common in the 22q11.2 deletion syndrome (DS) population. Structural anomalies and retrognathia may predispose these patients to obstructive sleep apnea (OSA). The current association of OSA in this population is not defined.

Objective

(1) Define the frequency of OSA in 22q11.2 DS patients referred for polysomnography (PSG). (2) Determine if OSA is present before and/or after surgery to correct velopharyngeal insufficiency (VPI). (3) Determine effect of prior adenotonsillectomy on OSA following VPI surgery.

Methods

Retrospective review of children treated from 2006 to 2013 in a tertiary care setting identified by ICD-9 758.32 (velocardiofacial syndrome) and 279.11 (DiGeorge syndrome). Surgical history and PSG data were abstracted from the identified records.

Results

We identified 323 patients with 22q11.2 DS; 57 (18%) were screened at any point in care using PSG and 15 patients had PSG at multiple time points in care. In most cases, indication for PSG was sleep disordered breathing or pre-operative planning. Overall, 33 patients met criteria for OSA on PSG, accounting for 10.2% of our study population; however, the percentage of patients with OSA was significantly higher within the group of 57 patients (58%) who were screened with PSG.

Twenty-one of the screened patients (54%) had PSG prior to any pharyngeal surgery and had mild to severe OSA (obstructive apnea/hypopnea index (AHI): median 5.1/h, range 1.9–25.6). Eighteen patients had PSG after adenotonsillectomy; 8 of these patients (44%) had mild to moderate OSA (median AHI 2.95/h, range 1.9–5.4). Seventeen patients had PSG after VPI surgery (palatopharyngeal flap (PPF) n = 16, sphincteroplasty n = 1). Nine of these patients (53%) had mild to severe OSA (median AHI 3/h, range 1.9–15). Patients who underwent adenotonsillectomy prior to VPI surgery had similar prevalence of OSA (50%, n = 12) than those who did not (OSA: 60%, n = 5, p = 0.70). Most children had mild OSA.

Conclusion

Prevalence of OSA in this population of 22q11.2 DS patients is higher than expected in the general population. OSA risk is highest after VPI surgery, and may be decreased by adenotonsillectomy. Providers should have awareness of increased prevalence of OSA in patients with 22q11.2 DS. Close monitoring for OSA is warranted given the likelihood of subsequent surgical intervention that can worsen OSA.

Introduction

22q11.2 deletion syndrome (DS) occurs in approximately 1 in 4000 live births and is identified in most patients with DiGeorge, velocardiofacial, and conotruncal anomaly face syndromes [1]. In addition to the characteristic pattern of conotruncal cardiac anomalies, a significant number of common otolaryngologic problems are found within these syndromes [2]. Patients with 22q11.2 DS present with structural anomalies including retrognathia [3], which may predispose them to obstructive sleep apnea (OSA) [4], [5], [6]. The prevalence of OSA in this population has not previously been studied.

The majority of 22q11.2 DS patients have palatal anomalies, including palatal clefting and velopharyngeal insufficiency (VPI) in the absence of overt or submucous cleft palate [2], [7]. Previous literature suggests that up to 37% of patients with cleft palate require surgery to correct VPI [8], generally through pharyngeal flap surgery or sphincter pharyngoplasty. Surgery to correct VPI carries a risk of causing or exacerbating OSA due to alteration of the naso/oro-pharynx which carries a potential for airway compromise [9]. In the 22q11.2 DS population, a wide posterior pharyngeal flap is often necessary due to the craniofacial dimensions and severity of the velopharyngeal dysfunction. Given the increased risk of OSA, some VPI treatment paradigms recommend that adenotonsillectomy be performed prior to pharyngeal flap surgery in order to minimize incidence of OSA postoperatively [10].

Little is known about OSA in the 22q11.2 DS population, with only one case report describing a child with 22q11.2 DS with both obstructive and central sleep apnea. Tonsillectomy benefited the patient by decreasing her respiratory disturbance index and improving nadir oxygen saturation [11]. It is well established that adenotonsillectomy is effective in treating OSA in nonsyndromic patients [12]. Surgeons may be reluctant to perform adenotonsillectomy in patients with 22q11.2 DS as adenotonsillectomy has been shown to uncover or worsen VPI [13].

It is important to define the baseline frequency of OSA in in 22q11.2 DS patients since many 22q11.2 DS patients have VPI and corrective surgery may cause or worsen OSA [14]. The current study sought to determine the prevalence of OSA in 22q11.2 DS patients referred for polysomnography (PSG) through a retrospective review of patients treated at the Children's Hospital of Philadelphia (CHOP) from 2006 to 2013. Secondary objectives evaluated presence of OSA before and/or after surgery to correct VPI, and the effect of adenotonsillectomy on OSA in this patient population.

Section snippets

Methods

After institutional review board approval was obtained, we conducted a retrospective chart review of consecutive patients seen between January 1, 2006 and July 1, 2013 at CHOP. Consent was waived for this retrospective study. Potential cases were identified by querying billing records for International Classification of Diseases, Ninth Revision (ICD-9) codes 758.32 (velocardiofacial syndrome) and 279.11 (DiGeorge syndrome). Inclusion criteria were male or female patients up to age 18 with

Results

The search of billing records for the diagnosis of velocardiofacial syndrome or DiGeorge syndrome yielded 323 total patients, of whom 57 (18%) were screened at any point in care using PSG. Table 1 shows the demographic and clinical characteristics of the screened population. In the cohort of patients not included in the study who had 22q11.2 DS but were not screened with PSG (n = 266), 40 (15%) had either adenotonsillectomy or adenoidectomy, 44 (17%) had palate surgery for VPI (38 PPF and 6 cleft

Discussion

In this paper, we have shown that OSA is common in the 22q11.2 DS population. We have also examined AHI trends as they relate to point of intervention. The prevalence of OSA among all 22q11.2 DS patients screened by PSG was 58% and prevalence was relatively consistent at each PSG time-point—pre-intervention, post-adenotonsillectomy, and post-VPI surgery. It is difficult to assess OSA prevalence within the larger 22q11.2 DS population, as there was selection bias in which patients were referred

Conclusions

This study is one of the first to provide information regarding the prevalence of OSA in 22q11.2 DS patients and confirms that it is higher than expected in the general population. Providers should have awareness of increased prevalence of OSA in patients with 22q11.2 DS. Close monitoring for OSA is warranted given the underlying structural anomalies and hypotonia that predispose them to OSA and the likelihood of subsequent surgical intervention that can worsen OSA.

Acknowledgement

We thank Rachel S. Hammond, MS for her assistance with biostatistics.

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