Sleep-Disordered Breathing in Patients With Chiari Malformation Type II

Abstract

PURPOSE: Children with Chiari malformation type II (CM-II) have the tendency for sleep apnea syndrome (SAS). The incidence of sleep disordered breathing (SDB) in this population has not been well documented both locally and globally. The aim of this study was to estimate the frequency, mechanisms and possible predictive factors of SDB in patients with CM-II in our hospital. The anatomical and functional integrity of both respiratory circuits and lower cranial nerves controlling the upper airway is necessary for breathing control during sleep. The latter structures may be altered in CM-II, and a few investigators have reported CM-II related SDB. METHODS: This study was carried out at King Khalid University Hospital Sleep Disorders Centre, Riyadh, Saudi Arabia, between January 2002, and July 2009. All MRI diagnosed CM - II patients were routinely referred from the neurosurgical clinic to the Sleep Clinic underwent full polysomnography. The polysomnographic data was analyzed using descriptive statistics. RESULTS: Sixteen children (five females) were enrolled in the study; their mean age was 4.7 (range 0.8-10) years and their mean BMI was 18.05 (range 15.4-25.4) kg/m2. For the whole group, the mean Apnea Hypopnea Index (AHI) was 6.3/hour (range: 0.2-24.5) and AHI was ≥ 11 in 3 of 16 sleep studies (18.75%%). The mean Central Apnea Hypopnea Index (CAHI) was 5.9/hour (range: 0-24.5) and mean Obstructive AHI (OAHI) was 0.4/hour (range:0-2.9). The mean Arousal Index (MAI) was 15.11/hour (range: 5-34). CONCLUSION: There is a high incidence of SDB and definable sleep apnea in the CM-II. Disturbed sleep and Sleep Disordered breathing is most likely under-reported and treated in this population. CLINICAL IMPLICATIONS: We propose that all children with the condition should be screened at regular intervals both clinically and also by full polysomnography to detect SDB as early as possible. This will help in not only in planning early surgical intervention, but also preparing for possible post-operative complications.