Abstract
Introduction Intraoperative micro-Doppler (IOMD), intraoperative digital substraction angiography
(DSA), and microscope-integrated indocyanine green angiography are methods that guide
neurosurgical resection of arteriovenous malformations (AVMs) in the brain and minimize
the trauma of healthy tissue. In this study we emphasize the use of IOMD in AVM surgery,
analyzing the advantages and the limitations of this method.
Patients and Methods A total of 32 patients were diagnosed with an AVM. Supplying arteries and draining
veins were analyzed regarding hemodynamic profiles, flow velocities, pulsatility index
(PI), and resistance index (RI). Venous drainages were accompanied by arterial blood
flow disturbances that showed typical characteristics in all cases. We set an angle
of 60 degrees between the examined vessel and the probe to achieve a more reliable
and comparable measurement. Postoperative DSA was performed in all patients.
Results Supplying arterial blood vessels of AVMs could be identified by their characteristic
blood flow profiles with PI < 0.7 and RI < 0.55. Drainage veins in all 32 cases showed
normalized venous flow patterns without arterial flow turbulences at the end of the
surgical procedure. Postoperative DSA revealed a residual AVM in one patient.
Conclusions IOMD constitutes a safe, accurate, and low-cost imaging modality for evaluating blood
flow velocities and for optimal stepwise AVM elimination without unnecessary sacrifice
of veins. PI and RI are reliable parameters in diagnosing cerebrovascular malformations,
but systolic and diastolic flow velocities may vary to a greater extent. This phenomenon
has never been elucidated previously and therefore needs to be emphasized when using
this technique intraoperatively.
Keywords
arteriovenous malformation - micro-Doppler - intraoperative - vascular
