title: Intraoperative Flow Measurement by Microflow Probe During Spinal Dural Arteriovenous Fistula Surgery.
abstract: OBJECTIVE
  Flow measurement by microvascular ultrasonic flow probe is an established procedure in intracranial vascular surgery. This study tested the application of this procedure in spinal dural arteriovenous fistula (SDAVF) treatment.
  
  
  METHODS
  Data from 12 SDAVF patients who consecutively underwent microsurgical resection with the assistance of both microflow probe and indocyanine green videoangiography (ICG-VA) were retrospectively analyzed. Flowmetry was performed on a dilated perimedullary venous plexus at different distances from the fistula point (FP). In addition, measurements were made at different phases of surgery to address specific issues: at the beginning, to identify the fistula; after temporary clipping, to evaluate proper disconnection; and after section, to exclude residual filling.
  
  
  RESULTS
  Flowmetry was reliable in assessing both the value and direction of flow in all cases, thereby aiding fistula localization and confirming its disconnection. Indeed, fistula localization was helped by detection of increasing flow values approaching the FP (mean flow: 11 mL/min <10 mm vs. 3 mL/min >20 mm), while fistula disconnection was confirmed by a flow value lower than 1 mL/min (0-1 mL/min). Data from microflow probe measurements were concordant with ICG-VA data in all cases. In 3 cases, ICG-VA findings on fistula disconnection uncertain due to residual ICG dye were clarified by flowmetry.
  
  
  CONCLUSIONS
  With the limits of our small series, multistage intraoperative quantitative flow measurement is a feasible, safe, and reliable adjunct in the surgical treatment of SDAVFs. The procedure provides data helpful in guiding the surgical strategy or clarifying ICG-VA data when necessary.
authors.affiliation: Department of Neurosurgery, Padua University Hospital, Padua, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Della Puppa
authors.affiliation: Department of Neurosurgery, Padua University Hospital, Padua, Italy. Electronic address: orielarustemi@libero.it.
authors.forename: Oriela
authors.initials: O
authors.lastname: Rustemi
authors.affiliation: Department of Neurosurgery, Padua University Hospital, Padua, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Scienza
mesh_terms: D000328:Adult; D000368:Aged; D020785:Central Nervous System Vascular Malformations / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007208:Indocyanine Green; D007796:Laminectomy / Q000295:instrumentation / Q000379:methods; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008297:Male; D008866:Microsurgery / Q000295:instrumentation / Q000379:methods; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods*; D012189:Retrospective Studies; D012212:Rheology / Q000295:instrumentation* / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000295:instrumentation / Q000379:methods; D014741:Video Recording / Q000379:methods
chemical_list: D003287:Contrast Media; D007208:Indocyanine Green
keywords: Cerebrovascular surgery; Flowmetry; Microflow probe; Microsurgery; Spinal dural arteriovenous fistula; Spinal surgery