Equipment for Intraoperative Assessment of Sternal Collaterals

by Mark M. Levinson , MD
Hutchinson Hospital
Hutchinson, KS, USA

April 21, 2001

In an attempt to determine if the absence of sternal collaterals predisposes to sternal wound complications following IMA harvesting, I have searched for a method that would reliably and inexpensively assess chest wall collateral flow. A 5 mm endoscopic straight tip doppler probe (as used by general surgeons during laparoscopic procedures) proved to be inadequate.

Recently, I have been very successful in detecting doppler flow signals in the intercostal arteries using a special bayonet doppler probe supplied by Koven Technology . This is the only probe I have found that has the correct angle at the tip. The bayonet probe can be positioned correctly over the intrathoracic portion of the intercostal spaces and doppler flow signals easily detected in the intercostal arteries. Flow signals have also been detected in the subcostal and superior epigastric vessels with this probe.

The photograph below shows the bayonet probe tip.

This probe is connected to a Koven (or Hadeco) hand held MiniDop ES-100x unit. Signal acquisition requires a 10 MHz amplifier . Only the probe tip needs to be sterilized. The photograph below shows the MiniDop ES-100x and the 10 MHz amplifier. The probe inserts into the amplifier. There is an on-off button on the amplifier.

Use of this equipment has allowed me to locate intercostal and subcostal flow signals in every case so far. Digital compression of the IMA against the chest wall one or two interspaces proximal to the signal eliminates all intercostal or subcostal flow in about 10% of cases. In the remaining 90%, the signal either remains or is increased.

It is my hypothesis that complete loss of the flow signal at all interspaces indicates absent chest wall collaterals. This finding implies that chest wall blood supply is completely IMA dependent and thus contraindicates IMA harvesting. However, proof of this hypothesis is not possible yet as the data is preliminary. A multicenter study is currently being organized to help determine if the incidence of sternal wound complications is higher in patients with absent collateral flow. If you wish to participate in this study, please email Mark M. Levinson

Total cost of this system is about $1,700 USA. You may contact Koven Technology at:

Koven Technology
12125 Woodcrest Executive Drive
Suite 220
St. Louis, MO 63141 USA

Phone: 314-542-2101
Fax: 314-542-6020
Email: info@koven.com
Web: www.koven.com