Artikel
The role of intraoperative microdoppler in cerebral and spinal arterio-venous malformations
Die Bedeutung des intraoperativen Mikrodopplers bei zerebralen und spinalen Gefäßmalformationen
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Autoren
Veröffentlicht: | 23. April 2004 |
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Gliederung
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Objective
When arterio-venous malformations (AVM) and -fistulas (AVF) are resected and ligated by a neurosurgical approach, all essential vessels and healthy brain and spinal tissue have to be preserved. The surgical approach has to focus first on the arterial blood supply before draining veins are obliterated. Otherwise compromising draining veins during the preparation of an AVM will lead to hazardous congestive bleeding. In this context PW-intraoperative microdoppler (IOMD) was evaluated for its value in guiding the surgical strategy.
Methods
Since 1/2001, 64 cranial AVMs and 12 dural AVFs as well as 9 spinal dural AVFs were operated on in our clinic. IOMD investigations were performed on the supplying and draining vessels to analyze their hemodynamic profile, flow velocities, pulsatility index (PI) and resistance index (RI).
Results
IOMD measurements of systolic and diastolic blood flow were not comparable to data obtained from transcranial doppler (TCD) evaluations. Blood flow velocities by IOMD were significantly lower than by TCD investigations. Nevertheless supplying arterial blood vessels of AVM and AVF were reliable identified by their indices, especially a characteristic low PI<0.72. Venous drainages carrying arterialized blood, showed characteristics of intermediate flow with abnormal high systolic and diastolic blood flow, providing a reliable diagnosis in all investigated pathologies.
Conclusions
In principle IOMD is an easy-to-handle tool, reliable for identifying arterial and venous blood vessels of cerebral arteriovenous malformations, thereby enhancing the safety of the surgical procedure. The young vascular surgeon, in particular, will profit from this quick investigation designed to prevent serious complications. However, further technical improvements have been initiated because we found that high doppler probe angles and low pulse repitition frequencies (PRF) are the major reasons for unexpected low systolic and diastolic flow measurements.