title: Optimizing ventriculoperitoneal shunt placement in the treatment of idiopathic intracranial hypertension: an analysis of neuroendoscopy, frameless stereotaxy, and intraoperative CT.
abstract: OBJECTIVE
  Cerebrospinal fluid shunting can effectively lower intracranial pressure and improve the symptoms of idiopathic intracranial hypertension (IIH). Placement of ventriculoperitoneal (VP) shunts in this patient population can often be difficult due to the small size of the ventricular system. Intraoperative adjuvant techniques can be used to improve the accuracy and safety of VP shunts for these patients. The purpose of this study was to analyze the efficacy of some of these techniques, including the use of intraoperative CT (iCT) and frameless stereotaxy, in optimizing postoperative ventricular catheter placement.
  
  
  METHODS
  The authors conducted a retrospective review of 49 patients undergoing initial ventriculoperitoneal shunt placement for the treatment of IIH. The use of the NeuroPEN Neuroendoscope, intraoperative neuronavigation, and iCT was examined. To analyze ventricular catheter placement on postoperative CT imaging, the authors developed a new grading system: Grade 1, catheter tip terminates optimally in the ipsilateral frontal horn or third ventricle; Grade 2, catheter tip terminates in the contralateral frontal horn; Grade 3, catheter terminates in a nontarget CSF space; and Grade 4, catheter tip terminates in brain parenchyma. All shunts had spontaneous CSF flow upon completion of the procedure.
  
  
  RESULTS
  The average body mass index among all patients was 37.6 ± 10.9 kg/m2. The NeuroPEN Neuroendoscope was used in 44 of 49 patients. Intraoperative CT scans were obtained in 24 patients, and neuronavigation was used in 32 patients. Grade 1 or 2 final postoperative shunt placement was achieved in 90% of patients (44 of 49). In terms of achieving optimal postoperative ventricular catheter placement, the use of iCT was as effective as neuronavigation. Two patients had their ventricular catheter placement modified based on an iCT study. The use of neuronavigation significantly increased time in the operating room (223.4 ± 46.5 vs. 190.8 ± 31.7 minutes, p = 0.01). There were no shunt infections in this study.
  
  
  CONCLUSIONS
  The use of iCT appears to be equivalent to the use of neuronavigation in optimizing ventricular shunt placement in IIH. Additionally, it may shorten operating room time and limit overall costs.
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany, New York.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Yim
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany, New York.
authors.forename: M
authors.initials: M
authors.lastname: Reid Gooch
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany, New York.
authors.forename: John C
authors.initials: JC
authors.lastname: Dalfino
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany, New York.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Adamo
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany, New York.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Kenning
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods* / Q000592:standards; D044583:Neuroendoscopy / Q000379:methods* / Q000592:standards; D038361:Neuronavigation / Q000379:methods* / Q000592:standards; D011559:Pseudotumor Cerebri / Q000000981:diagnostic imaging / Q000601:surgery*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards; D016896:Treatment Outcome; D017287:Ventriculoperitoneal Shunt / Q000379:methods* / Q000592:standards; D055815:Young Adult
keywords: BMI = body mass index; FOHR = frontal and occipital horn ratio; IIH = idiopathic intracranial hypertension; LP = lumboperitoneal; NeuroPen; VP = ventriculoperitoneal; iCT = intraoperative CT; idiopathic intracranial hypertension; intraoperative CT; ventriculoperitoneal shunt placement