An Opening in the Abdomen An Opening in the Market: Hernia Tensiometer GROUP 2: Martha Ingram Megan Johnston Chelsea Samson

Laparoscopic Open

“Tension-Free” Repair Method

Background: $ Inpatient discharges from Healthcare Cost and Utilization Project $ Outpatient estimates from 2006 CDC National Survey of Ambulatory Surgery $ Total number of ventral hernia repair procedures performed in the U.S. $ Extrapolated operation dollars from 2006 to 2009 monies using Consumer Price Index Methods: “Currently, there is a lack of standardization in ventral hernia repair procedures, with widespread variation in delivery” Lack of standard delivery  Increased complications post-surgery  increased cost

Result s  154,278 inpatient + 193,543 outpatient = 348,000 operations  1 inpatient operation = $15,374  1 outpatient operation = $3,745  Total Expenditure in Procedures =$3.1 billion on VHR

Mean Cost of Ventral Hernia Repair Procedures over Time *adapted from BK Poulose, J Shelton, DE Moore, W Nealon, D Penson, M Holzman, Making the Case for Hernia Research Year Cost per Discharge

*adapted from BK Poulose, J Shelton, DE Moore, W Nealon, D Penson, M Holzman, Making the Case for Hernia Research Mean Frequency of Ventral Hernia Repair Operations over Time Year Number of Discharges

The application of an intra-operative tension-measuring device could increase understanding of and prevent hernia recurrence, significantly decreasing costs

Get a force (Newtons) and want to know if failure will occur… Tension (N) Probability of Recurrence 100 % 90 % 80 % 70 % 60 % 50 % 40 % 30 % 20 % 10 % 0 %

Clamp both hernia edges between metal plates Large, sharp serrations hold tissue in place Lash force sensors across opening

Static arm Mobile arm Digital display Gear to wind hernia edges together Force Sensor

Calibration 1. Initial calibration –Known weights (0-5 kg) applied –Measure voltage output in Labview –Convert to force 2. Tare –Zero weight  zero force 3. Pre-operative testing –Surgeons will calibrate with weights every 5-10 uses to confirm precise results (calibration curve is still relevant)

Timeline – Near Future Attach sensors and test with weights – today Test on porcine model – 4 th week of Feb Modify design – early March