title: Symptomatic cervical disc herniation in a pediatric Klippel-Feil patient: the risk of neural injury associated with extensive congenitally fused vertebrae and a hypermobile segment.
abstract: METHODS
  A case report.
  
  
  OBJECTIVE
  To report the occurrence of a herniated cervical disc following a high-impact activity in a pediatric Klippel-Feil patient who presented with spinal cord compression, myelopathy, and myelomalacia requiring posterior instrumented fusion followed by an anterior discectomy and fusion at the hypermobile nonfused segment.
  
  
  BACKGROUND
  The primary hallmark of Klippel-Feil syndrome (KFS) is the presence of at least one congenitally fused cervical segment. Studies have reported the potential risk of cervical injury from hypermobility associated with the nonfused cervical segment in KFS. The manifestation of a cervical disc herniation in the pediatric KFS patient is rare. To the authors' knowledge, the development of a symptomatic cervical herniated disc attributed to mechanical fatigue following a high-impact activity has not been addressed in the literature with respect to the pediatric KFS patient having extensive cervical fusion and a hypermobile segment.
  
  
  METHODS
  A 16.8-year-old KFS boy with occipitalization of C1 and fusion of C2-C3 and C4-T1 presented with myelopathy, severe cord compression, and myelomalacia stemming from a left-sided herniated cervical disc at C3-C4 with onset following an 8-foot high rooftop jump. On radiographic evaluation, the patient's C3-C4 segment was hypermobile.
  
  
  RESULTS
  The patient was operatively managed via a same-day combined posterior-anterior procedure. The posterior aspect of the procedure entailed a posterior lateral mass plate-screw fixation at C3-C4 with autologous iliac crest bone fusion. Anteriorly, a discectomy was performed at C3-C4 with application of an interbody tricortical autograft. After surgery, the patient wore a halo vest for 3 months, followed by a soft collar for an additional 3 months. On final follow-up at 39 months, the patient was asymptomatic with no instrumentation-related complications, fusion of the posterior graft-bed and anterior interbody graft was noted, and cervical alignment was maintained.
  
  
  CONCLUSIONS
  A hypermobile segment in the pediatric KFS patient is a risk factor that may lead to cord compression. A symptomatic herniated cervical disc may develop from an excessive mechanical load stress in a pediatric KFS patient with multiple fused segments. In such a patient, a same-day combined posterior-anterior procedure provides cord decompression and stabilizes the spine with a favorable outcome.
authors: Division of Health Sciences, University of Oxford, Oxford, England.
authors: Dino
authors: D
authors: Samartzis
authors: John P
authors: JP
authors: Lubicky
authors: Jean
authors: J
authors: Herman
authors: Prakasam
authors: P
authors: Kalluri
authors: Francis H
authors: FH
authors: Shen