The Operation for Metabolic Bone Disease in Children

Patient Positioning

  • Baseline IOM potentials prior to positioning: Electrophysiological monitoring (where available) should be established after induction of anesthesia and then confirmed once the patient is positioned.
  • Optimize spinal alignment during positioning: Optimal reduction of any craniovertebral deformity must be achieved prior to surgery. If there is severe myelopathy or instability, then prior immobilization in a halo-body orthosis should be considered.
  • Pin fixations for prone procedure involving occiput and cervical spine: Occipitocervical decompression and fixation procedures are performed in the prone position. The head should be immobilized with pin fixation.
  • Check alignment after positioning: Fluoroscopy is used to confirm adequate craniovertebral alignment prior to commencing the surgery.  

Surgical Approach

Posterior midline approach

  • Decompression and stabilization: For occipitocervical decompression and stabilization procedures a standard midline posterior approach is used.
  • Expose facets if lateral fusion planned: If pedicle or lateral mass screws are to be placed, then the muscle reflection needs to extend more laterally to allow visualization of the line of the facet joint.
  • Anticipate cartilaginous midline of C1 in young: In metabolic disorders, particularly in younger children, the posterior C1 ring is often cartilaginous and incomplete. Dissection needs to be carried out with caution to avoid inadvertent dural injury.
  • Caudal extent varies with disease: The inferior extent of the approach is dictated by circumstance. Exposure from the occiput to the lower border of C2 suffices for most craniovertebral stabilization procedures. 

Transoral approach

  • Decompression of craniovertebral junction: This approach is indicated for irreducible compression at the craniovertebral junction. This permits access from the lower third of the clivus to the body of C2.

Anterior cervical approach

  • Ventral decompression and deformities: This approach is used for subaxial ventral compression or severe midcervical deformity unresponsive to traction.

Intervention

Closure

  • Standard closure: Meticulous attention to wound closure and skin care is important to prevent wound-related complications and deep infection. Any metal instrumentation, particularly at the occiput, should be positioned so that there will be adequate soft tissue cover.  The wound is closed in layers.
  • Drain can be used: A wound drain may be used but should remain for no longer than 24 hours to reduce the risk of infection.