Dual pump irrigation/aspiration system and method for determining joint pressure
View Patent ↗A dual pump irrigation/aspiration pump system capable of operating in a plurality of different modes suitable for a variety of different endoscopic surgical procedures. The system monitors actual or calculated intra-articular pressure and adjusts flow to maintain surgeon requested pressure at the surgical site while controlling outflow. The irrigation/aspiration pump system has an inflow pump and tubing dedicated to communicating fluid to the surgical work site and an outflow pump and tubing dedicated to removing fluid from the work site at a controlled rate. The system further has different size inflow and outflow pumps and tubing cassettes, a subsystem for altering the outflow fluid flow rate to accommodate a surgical tool and a subsystem for declogging the surgical tool in the event of blockage. In a preferred embodiment a pressure control system provides inferred pressure information representative of the pressure at the work site.
1. A method for determining and controlling the pressure at a surgical work site during an endoscopic surgical procedure utilizing a fluid inflow pump, inflow tubing and an inflow cannula for conveying fluid from a fluid source to the surgical work site, a fluid outflow pump, outflow tubing and an outflow cannula for conveying fluid from the work site to a drain, the method further utilizing a pressure feedback control loop intended to maintain fluid pressure at the surgical work site at a pressure set point by adjusting pressure and flow parameters to maintain the pressure at the work site at or near the set point pressure, the method comprising the steps of:
providing a first pressure determining means comprising a first pressure sensor near the inflow pump to measure pressure at the output of the inflow pump;
providing a second pressure determining means comprising a second pressure sensor at the surgical work site to measure actual pressure at the surgical work site;
providing a third pressure determining means comprising a pressure inferring system to calculate the pressure at the surgical work site using known and measurable pressure and fluid flow characteristics;
determining whether said second pressure determining means comprising a pressure sensor at the surgical work site is present and operational;
if said second pressure sensor is present and operational, selecting said second pressure sensor as the source of the value for the pressure at the surgical work site to be used in the feedback control loop; and
if said second pressure sensor is not present and operational, selecting either said first or third pressure determining means as the source of the value for the pressure at the surgical work site to be used in the feedback control loop.
2. A method according to claim 1 wherein the measurement of pressure and flow parameters is made periodically during the surgical procedure.
3. A method according to claim 2 wherein the periodic time period is approximately 1-20 milliseconds.