Neurosurgery notes/Procedures/Cranial procedures/CSF procedures/EVD

EVD

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CSF procedures
  • Three methods
    • Free hand
      • Should not use it that much
    • Neuronavigational
    • U/S guided
  • Procedure
    • Place on right side
      • Nondominance for language function in >90% of patients
    • The patient is maintained with head of bed elevated at 45° in the supine position. Hair is removed using clippers and the scalp is prepared in a sterile fashion.
    • A burr hole is placed at Kocher's point (10 cm nasion and 3 cm lateral to midline, along the mid pupillary line) to avoid the superior sagittal sinus and frontal cortex motor strip.
      • This is placed in through middle frontal gyri
    • Local anesthesia, a linear skin incision is made down to the bone and the periosteum is scraped.
    • A twist drill is used to penetrate the cranium in the trajectory determined for ventricular cannulation, and the pia and dura are pierced with a scalpel.
    • The ventricular catheter is primed and passed no more than 7 cm,
      • Aiming in a coronal plane toward the medical canthus of the ipsilateral eye
      • Anteroposterior plane toward a point 1.5 cm anterior to the ipsilateral tragus,
      • Toward the ipsilateral Foramen of Monro.
    • Once CSF flow is visualized after removal of catheter stylet, it can be transduced to obtain an opening intracranial pressure.
      • Sutured securely in place, and then connected to an external drainage system.
  • Complications
    • Haemorrhage and inadvertent placement into brain tissue is reported in 10–40% of cases.
    • EVD has 9.3% infection rates (from EVD audit)
      • Definition of EVD infection by Keong et al. 2012 (Silver study)
        • Clinical meningitis requiring treatment, accompanied by clinical signs and CSF pleocytosis,
        • Whether or not organisms were successfully isolated were not important.
      • Infection rate increase significantly if more than 8 days
      • 70% gram + infections
        • 50% being staphylococcus infections
      • How to reduce infection
        • Jamjoom et al 2018: Prospective observational trial 495 EVD
          • Data from mix aetiology of HCP: 65% are SAH
          • Tunneled >5cm through the skin away from the point of entry through a separate incision
          • Do not sample frequently
          • Use bactiseal EVD: although in EVD audit has not shown to reduce infection but in Shunt it has shown to have reduced infection rates
      • Jamjoom et al 2018: median length of treatment with antibiotics was 10 days
  • Post EVD care:
    • Set at 20cmH20
    • Do not regular sample
    • Evidence for early removal of EVD
      • Rao et al 2019
        • Reduce LOS
        • Reduce complications
          • Non functioning
          • Infectino rates
        • Reduce CSF diversion rates (shunting rates)
          • Theory is if it is too low you reduce CSF reabsorption through arachnoid villi and making it easier to block.
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