title: Non-assisted versus neuro-navigated and XperCT-guided external ventricular catheter placement: a comparative cadaver study.
abstract: OBJECTIVE
  Accurate placement of an external ventricular drain (EVD) for the treatment of hydrocephalus is of paramount importance for its functionality and in order to minimize morbidity and complications. The aim of this study was to compare two different drain insertion assistance tools with the traditional free-hand anatomical landmark method, and to measure efficacy, safety and precision.
  
  
  METHODS
  Ten cadaver heads were prepared by opening large bone windows centered on Kocher's points on both sides. Nineteen physicians, divided in two groups (trainees and board certified neurosurgeons) performed EVD insertions. The target for the ventricular drain tip was the ipsilateral foramen of Monro. Each participant inserted the external ventricular catheter in three different ways: 1) free-hand by anatomical landmarks, 2) neuronavigation-assisted (NN), and 3) XperCT-guided (XCT). The number of ventricular hits and dangerous trajectories; time to proceed; radiation exposure of patients and physicians; distance of the catheter tip to target and size of deviations projected in the orthogonal plans were measured and compared.
  
  
  RESULTS
  Insertion using XCT increased the probability of ventricular puncture from 69.2 to 90.2 % (p = 0.02). Non-assisted placements were significantly less precise (catheter tip to target distance 14.3 ± 7.4 mm versus 9.6 ± 7.2 mm, p = 0.0003). The insertion time to proceed increased from 3.04 ± 2.06 min. to 7.3 ± 3.6 min. (p < 0.001). The X-ray exposure for XCT was 32.23 mSv, but could be reduced to 13.9 mSv if patients were initially imaged in the hybrid-operating suite. No supplementary radiation exposure is needed for NN if patients are imaged according to a navigation protocol initially.
  
  
  CONCLUSIONS
  This ex vivo study demonstrates a significantly improved accuracy and safety using either NN or XCT-assisted methods. Therefore, efforts should be undertaken to implement these new technologies into daily clinical practice. However, the accuracy versus urgency of an EVD placement has to be balanced, as the image-guided insertion technique will implicate a longer preparation time due to a specific image acquisition and trajectory planning.
authors.affiliation: Service de Neurochirurgie, Département de Neurosciences cliniques, Faculté de Médecine, Hôpitaux Universitaires de Genève, Geneva, Switzerland, ogautschi@gmail.com.
authors.forename: Oliver P
authors.initials: OP
authors.lastname: Gautschi
authors.forename: N R
authors.initials: NR
authors.lastname: Smoll
authors.forename: M
authors.initials: M
authors.lastname: Kotowski
authors.forename: B
authors.initials: B
authors.lastname: Schatlo
authors.forename: M
authors.initials: M
authors.lastname: Tosic
authors.forename: B
authors.initials: B
authors.lastname: Stimec
authors.forename: J
authors.initials: J
authors.lastname: Fasel
authors.forename: K
authors.initials: K
authors.lastname: Schaller
authors.forename: P
authors.initials: P
authors.lastname: Bijlenga
mesh_terms: D002102:Cadaver; D057785:Catheters; D004322:Drainage / Q000379:methods; D006801:Humans; D006849:Hydrocephalus / Q000601:surgery*; D038361:Neuronavigation / Q000379:methods*; D019635:Neurosurgical Procedures / Q000295:instrumentation / Q000379:methods*; D061646:Operative Time; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods*