Intraoperative Doppler

What are Intraoperative TCD Measurements?

Intraoperative Doppler measurements are the detection of blood flow velocity in small micro-vessels inside the sterile field during surgery. Typically a micro-Doppler probe with a frequency of 16 MHz or 20 MHz is used.

The probe is placed directly on the wet tissue or the external wall of the blood vessel.

How to use TCD for Intraoperative Doppler Measurements

Most transcranial doppler manufacturers include a micro-vascular probe for intraoperative measurements with their TCD machines. The most common micro-probe frequency is 16 MHz, but 20 MHz Doppler probes can also be found.

The microvascular head of the probe is very small, of the order of just an mm or so. The probe must be sterile and is used inside the sterile field. The surgeon will place the tip of the probe directly in the region of interest, whether on wet tissue to identify underlying vessels or directly on a small vessel or graft to verify the flow of blood in the target blood vessel.

Intraoperative Doppler Probe
16 MHz Intraoperative Doppler Probe
Intraoperative Doppler 16 MHz Probe

16 MHz Doppler Probe

Intraoperative probe

Using the Dolphin TCD for Intraoperative Doppler Measurements

All of the Dolphin transcranial doppler machines and models include a port for connecting a 16 MHz microvascular probe. The probe is based on Pulse Wave (PW) Doppler technology, which means the measurements are made from a specific distance from the probe head towards the blood vessel.

This technology provides the surgeon with tools to assess the risk of removing an aneurism or a tumor, as well as validate the sufficient blood flow rate through the target vessel of interest. 

The Dolphin intraoperative measurement software includes a dedicated protocol to simplify the measurement process and provide appropriate documentation of the measurement findings.

Expected Results of Intraoperative Doppler Measurements

Intraoperative Doppler measurements are used primarily to verify appropriate blood flow in the vessel or graft of interest and the direction of that blood flow.

In addition, the use of PW microvascular intraoperative Doppler probes is to determine the distance from the wall of the blood vessel in order not to damage the vessel during various surgical procedures such as tumor removal.

Selected Literature for Intraoperative Measurements

Intraoperative microvascular Doppler monitoring of blood flow within a spinal dural arteriovenous fistula: a precious surgical tool, Domenico Gerardo Iacopino, Maria Giusa, Alfredo Conti, Salvatore Cardali, And Francesco TomaselloNeurosurg Focus 10 (2):Clinical Pearl, 2001

Intraoperative microvascular Doppler ultrasonography in cerebral aneurysm surgery, Ruediger Stendel, Terttu Pietilä, Ali Abo Al Hassan, Andreas Schilling, Mario BrockJ Neurol Neurosurg Psychiatry 2000;68:29–35

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