LAUSR

Klippel- Feil Sequence (KFS) is a rare congenital condition that classically presents with a triad of congenital cervical spine fusion, reduced cervical spine flexion and low posterior hairline. KFS has been associated with several comorbidities including congenital heart defects, hearing loss, renal dysfunction, Chiari malformation and sleep disordered breathing (SDB). The co-occurrence of SDB and chiari malformation type 1 (CM1) has been reported in multiple individuals. However, the pathological basis of the connection between CM1 and SDB in the setting of KFS is not clearly understood. Here we present a pediatric case report of a patient with KFS, SDB, drooling and dysphagia. The drooling and dysphagia prompted an MRI that revealed CM1. Baseline polysomnogram (PSG) showed mild central sleep apnea with apnea-hypopnea index (AHI) 6.06 comprised of central apnea index 4.81 and obstructive apnea index 1.28. Posterior fossa decompression of this patient, following neurology recommendations, resolved majority of the symptoms, namely the drooling, nocturnal cough, dysphagia and sleep disturbances. However unexpectedly repeat polysomnogram eight weeks after posterior fossa decompression revealed worsening central sleep apnea despite the patient being clinically asymptomatic. Taken together this case highlights the point that while it is critical to recognize the association of SDB in the setting of KFS, decompression alone may not be sufficient to completely alleviate SDB and/or certain neurological symptoms such as nocturnal coughing. Our observations are consistent with the hypothesis that SDB in a setting of KFS is multifactorial and pathophysiology is not clearly understood.