This is the first Transonic in Action blog: the beginning of an irregular series that will detail Transonic’s device utility in daily medicine.

The aneurysm surgery in question took place earlier this month in Germany, performed by a well-respected surgeon and his staff with a Transonic representative in attendance, and a Transonic FlowXL for flow measurement.

The patient was a 22yo male who had been transferred from another institution due to the urgency and complexity of the surgery he required (multiple EC-IC and IC-IC bypasses because of multiple branches exiting the aneurysm dome.)

The surgeon required a FlowXL for the case, specifically, as he said, for objective data—direct and precise measurement of the requisite blood flow in the two main artery branches exiting the aneurysm*, and also to measure the cut flow index on the donor vessel**, in this case, a single frontal branch of the superficial temporal artery.

Given the delicacy and complexity of the surgery, the surgeon had prepared in advance, drafting a decision tree of surgical strategies and alternatives that might be required as the surgery progressed. (Low-medium STA to M2 and M3 vs. high flow ECA to both MCA branches with a Y radial artery graft) based on the demand for flow and quantitative measurement (M1/M2 & M3, STA prox and distal) using the FlowXL.

These differing potentials carried much risk for the patient and required great planning and skilled execution from the surgical team. Throughout the surgery, the different treatment strategies outlined above needed continuous balance against actual demand for blood flow (as measured by the FlowXL) because the increasing blood flow and bypass complexity would commensurately increase the risk for stroke or death. This skilled medical tightrope walk became more precarious with each further step in the procedure until a “point of no return” was reached (excision of the aneurysm itself) after which all bypasses had to be completed and patent within 30 minutes, or the patient would likely suffer a massive stroke and lose his ability to speak and/or control the right side of his body. The FlowXL’s flow measurement for patency confirmation was invaluable at this stage, speeding the surgical decision-making process.

After 12 hours, the surgery was complete: two EC-IC bypasses (end to side and end to end STA to MCA), trapping and excision of the giant aneurysm. The surgical team saw complete filling of the brain by the bypasses, despite occlusion of the proximal brain vessel. Most importantly: the patient was extubated after the procedure, had no neurological deficits, and currently has a good prognosis, considering the circumstances. Truly a masterful surgery performed by a masterful surgeon and his team.

Transonic is humbly grateful to have supported, and we wish many more such medical victories to the dedicated, talented surgical team.

Notes:

*The FlowXL is the only system on the market that can precisely and noninvasively quantifies the flow within cerebrovascular vessels. Pre-anastomosis, this information allows surgeons to decide upon the exact flow volume that will be needed post-operatively to protect and sustain the cerebrovascular tissues in the region. Post anastomosis, the FlowXL allows surgeons to re-measure all flows in natives and grafts to confirm that sufficient flow has been restored throughout, or to alert the surgeon to an unseen flow deficit and prompt revision.

**Cut flow index (developed by Dr Fady Charbel, MD, FAANS, FACS, Head of Neurosurgery at University of Illinois Health) is a technique which derives a metric that can be used to help a surgeon predict neurosurgical graft success. The metric is derived in the following way: the intended graft vessel is severed and allowed to bleed while that flow is measured with Transonic equipment. Because there is no downstream backpressure in a severed vessel, this “cut flow” is logically assumed to be the maximum carrying capacity of the vessel; therefore, when the graft is anastomosed, its flow can again be measured and set as a fraction against the cut flow volume. This ratio represents the percentage of the maximum flow that the anastomosed graft is providing. If the surgeon deems this percentage sufficient, then CFI provided evidence that the graft will be successful, and if the surgeon deems that the percentage is insufficient, then CFI has prompted a revision that may be life-saving.