John F. Cummings

A miniature suture tensiometer for laparoscopic applications.

The tension applied to sutures can affect their performance. In laparoscopic procedures, the ability to tension sutures may be compromised by the confined space. The ability to accurately judge tension may also be compromised by lever arms of long instruments and interaction between the instrument and trocar. A miniature suture tensiometer that can be used in open and laparoscopic settings has been developed that demonstrates a maximum error of 0.05 lb over a 2-lb range. This device has been used in laparoscopic surgery to measure suture tension. The suture tension information gathered has been used in the development of a device that reliably delivers a secure knot in a laparoscopic setting.

Staple pull-out strength in an animal model of Cooper's ligament

STUDY OBJECTIVE To understand the effect of staple number, orientation, and configuration on pull-out strength in an animal model of Coopers ligament, and compare it with force to knot failure or suture breakage. DESIGN Comparative study (Canadian Task Force classification I). SETTING Ethicon Endo-Surgery Institute, Cincinnati, Ohio. SUBJECTS Fibrous connective tissues from bovine ischia were the tissue model. INTERVENTION Specimens were fixed in a cement-plaster compound and mounted in a tensiometer. Endoscopic staples were used to hold a loop of 0-braided polyester suture to the tissue. MEASUREMENTS AND MAIN RESULTS The suture loop was pulled perpendicularly away from tissue at a constant rate of 2.1 mm/second and peak force to staple pull-out was recorded. Two staple orientations and four staple configurations were studied. Tests were applied in a factorial arrangement. Ten-millimeter stitches of 0-braided polyester suture in the model were also tested. Maximum force to staple pull-out depended on staple number, orientation, and configuration. Peak force required to remove two staples was significantly higher than that to remove one. Spacing between two staples was less important. Pull-out strength was significantly higher when staples were placed parallel to tissue fibers. Stitches placed perpendicular to fibers failed at the knot or by suture breakage with a mean force approximately two times the peak force to remove two staples. CONCLUSION Two staples placed 2 to 5 mm apart parallel to tissue fibers resulted in the greatest pull-out strength of studied configurations.

Superior Dissecting Capability of A New Ultrasonic Device Improves Efficiency and Reduces Adhesion Formation

Background: Over the last two decades use of ultrasonic shears has grown in complex surgery where both precise dissection and meticulous hemostasis is required. With the introduction of HARMONIC® HD 1000i Shears (HD1000i), surgeons can now depend upon a single instrument to perform minimally-invasive dissection while securely sealing vessels up to and including 7 mm in diameter. This study was performed to compare HD1000i to the previous version of the device (HAR7) in sealing, dissecting and adhesion formation. Methods: Ex vivo testing in porcine tissues compared transection and marching speed, shaft temperature after repeated use, leaks at transection, seal reliability and burst pressures between HD1000i and HAR7. In an acute in vivo porcine study, initial hemostasis, hemostasis after a blood pressure challenge, thermal damage and dissecting ability were compared between HD1000i and HAR7. In a 30-day survival porcine study, initial hemostasis, seal durability with blood pressure challenge after the survival period, and adhesion formation were compared between the devices. Results: HD1000i had significantly faster transection and marching speeds (p<0.001) than HAR7, and similar shaft temperature, leaks at transection, seal reliability and burst pressure. In acute and survival studies, HD1000i had a high rate of hemostatic seals both initially and after blood pressure challenge, and thermal damage was not significantly different from HAR7. HD1000i was rated as superior in dissecting capability and had a significantly lower rate of adhesion formation than the HAR7 (p=0.005). Conclusion: With an integrated hand piece, the new HD1000i shears can simplify operating room setup, and should lead to fewer instrument changes, as the device is designed to both to perform dissection and seal large vessels. The versatility of this ultrasonic device may lead to more efficient surgical procedures and improved patient outcomes.

A Novel Advanced Bipolar Tissue Sealer Provides Improved Hemostasis and Less Thermal Damage

Background: Advanced bipolar devices are increasingly popular for cutting and coagulating vessels up to 7 mm in diameter. In this study, a recently introduced device with improved ergonomics, the ENSEAL® X1 Large Jaw (X1) was compared to another commercially-available advanced bipolar device. Methods: Ex vivo comparisons included jaw temperature after use and burst pressures of sealed vessels. In vivo acute and survival (30-day) studies in a porcine model evaluated hemostasis at initial sealing and after a simulated hypertensive crisis. Secondary endpoints included tissue sticking, thermal damage, adhesions and hemostasis at the distal tip of the end effector. Results: Both devices produced burst pressures that were supra-physiological with high rates of in vivo hemostasis both initially and after a blood pressure challenge. X1 showed significantly lower jaw temperatures after use, produced 41% less thermal damage and 88% greater hemostasis at the distal tip in deep mesentery. Conclusions: In these ex vivo and in vivo tests, advanced bipolar devices were shown to be reliable in sealing vessels over a range of sizes and vessel types. The novel design of X1 showed improved temperature control, thermal damage and hemostasis under difficult-to-access conditions. Clinical studies are needed to confirm these results.