Past, present, and future for surgical needles and needle holders

Buckling prevention strategies in nature as inspiration for improving percutaneous instruments: a review

A typical mechanical failure mode observed in slender percutaneous instruments, such as needles and guidewires, is buckling. Buckling is observed when the axial compressive force that is required to penetrate certain tissue types exceeds the critical load of the instrument and manifests itself by sudden lateral deflection of the instrument. In nature, several organisms are able to penetrate substrates without buckling while using apparatuses with diameters smaller than those of off-the-shelf available percutaneous needles and guidewires. In this study we reviewed the apparatuses and buckling prevention strategies employed by biological organisms to penetrate substrates such as wood and skin. A subdivision is made between buckling prevention strategies that focus on increasing the critical load of the penetration tool and strategies that focus on decreasing the penetration load of the substrate. In total, 28 buckling prevention strategies were identified and categorized. Most organisms appear to be using a combination of buckling prevention strategies simultaneously. Integration and combination of these biological buckling prevention strategies in percutaneous instruments may contribute to increasing the success rate of percutaneous interventions.

Tungsten-rhenium suture needles with improved properties for coronary artery bypass graft surgery

Suture needles are essential instruments for performing blood vessel anastomosis in coronary artery bypass graft (CABG) surgeries. Exceptional needle performance is needed now as never before because of the increasing prevalence of elderly patients with advanced stages of coronary disease and calcified tissue. The various properties that affect the performance of suture needles used in CABG surgery are reviewed and recent progress towards improving needle performance through the use of tungsten-rhenium alloys and novel lubricous needle coatings is presented. Substantial enhancement of properties beyond those exhibited by commercially available stainless steel suture needles has been made, including an approximate 40% increase in strength, 100% increase in stiffness, and superior multiple pass penetration performance in both synthetic rubber media and human cadaver carotid arteries (p < 0.01).

Experimental model for analyzing cutting resistance by various knives for cataract surgery

BACKGROUND

The trend in current cataract surgery towards clear corneal incision and sutureless procedures makes us realize the importance of wound construction. For optimal surgical outcomes, we need good surgical instruments. In this study, we employed a resistance recording system to analyze the characteristics of seven commercially available disposable cataract knives and to find clues for the future development of 'good' cataract knives.

METHODS

The cutting resistance was recorded during perpendicular penetrations of porcine scleral tissues by cataract knives. This data was processed and analysed mathematically with MATLAB software (The MathWorks, Inc, Natick, MA, USA) to see the resistance wave shapes and their derivatives to show the products' differing characteristics.

RESULTS

The wave shapes demonstrated product-dependent characteristics. The average maximum penetration resistance varied from 86.4 to 233 mN. The first order time derivatives also showed distinctive wave shapes.

CONCLUSION

We used an experimental model to analyze one aspect of a knife's character. This model can help give clues for future developments, although this is the initial step.

Improving the retention of suturing needles in surgical graspers

BACKGROUND

Surgical needles are usually held using dedicated grasping instruments. When the tissue to be penetrated is resilient, or the grasping force is low, the needle can swivel, causing it to deviate from the intended path, resulting in suboptimal tissue approximation. Needle swivel is particularly prevalent when needles are not held transversely in the jaws, but it is difficult to maintain a transverse grasp during surgery. An improved swivel-resistant grasper design is proposed.

METHODS

Conventional and swivel-resistant graspers were tested to quantify the benefits of the swivel-resistant design. Needles secured in the grasper were repeatedly distracted until swiveling occurred. The torque required to swivel the needles was statistically analyzed.

RESULTS

The swivel-resistant grasper offers greatly improved resistance to swivel (p = 0.01) when the needle is not held transversely.

CONCLUSIONS

The four-point contact afforded by the modified needle graspers imparts improved needle retention and resistance to swivel.

Resistance forces acting on suture needles

Understanding the resistance forces encountered by a suture needle during tissue penetration is important for the development of robotic surgical devices and virtual reality surgical simulators. Tensile forces applied to skin and tendon during suturing were measured. Fresh sheep achilles tendons were tensioned with a static load 4.9 N, 9.8 N or 19.6 N and sheepskin with 0.98 N, 2.9 N or 4.9 N static load. A straight 2/0 cutting suture needle in series with a load cell on a materials testing machine penetrated the tissue at 90 degrees with a velocity of 1, 5 or 10mm/s for each tissue tension (n=5). Continuous load versus displacement data was obtained and penetration load and stiffness were noted. The load versus displacement curve for skin during needle penetration demonstrated two characteristic peaks, corresponding to initial penetration and emergence of needle from the undersurface of the tissue. Increasing the tension within the tissue (skin and tendon) increased the amount of force required to penetrate the tissue with a suture needle (p<0.05). Needle displacement rate did not affect the resistance to needle penetration (p<0.05). This study provides a simple model for measuring force-feedback during needle penetration of soft tissues and is a good starting point for future studies of the penetration resistance properties of human tissues.

5th Annual David R. Boyd, MD Lecture: Revolutionary advances in wound repair in emergency medicine during the last three decades. A view toward the new millennium

This lecture provides an overview of advances in wound repair devised by our multidisciplinary team of physicians, scientists, and students. Our collective efforts have devised products, drugs, and concepts that are facilitating wound repair without infection and with the least possible scar. Some of the beneficial products and drugs developed or identified by our laboratory include nitrile examination and surgical gloves, magnification loupes, high pressure syringe irrigation, Shur Clens, as well as a wide variety of different wound closure techniques. In addition, our studies of the mechanism of wound injury, soil infection-potentiating fractions, dynamic and static skin tensions, and microflora of the skin have become important predictors of the outcomes of wound repair. During the new millennium, the computerized clinical information system as well as studies of tissue regeneration should dramatically change our approaches to wound repair.

Biomechanical performance of cutting edge surgical needles

The purpose of this study was to compare the biomechanical performance of cutting edge needles made of S45500 stainless steel alloy to Surgalloy stainless steel. The new high-nickel stainless steel alloy, Surgalloy, has superior performance characteristics over that of the other high-nickel stainless steel alloy, S45500. The Surgalloy needle is produced from a stronger stainless steel alloy than the S45500 needle. The Surgalloy needle has considerably greater resistance to bending than the needle produced from S45500 alloy. In addition, Surgalloy stainless steel has almost a twofold greater resistance to fracture than the S45500 stainless steel alloy.

Search for a scientific basis for continuous suture closure: a 30-yr odyssey

Continuous percutaneous and dermal suture closures have an important role in the approximation of long, linear lacerations in the emergency department. This report documents the scientific basis for these continuous closure techniques. In addition, a detailed description of these surgical closure techniques is presented.