Biomechanical performance of cutting edge surgical needles

Watkins, Frederick H.; London, Scott D.; Neal, Jeffrey G.; Thacker, John G.; Edlich, Richard F.

doi:10.1016/s0736-4679(97)00149-2

Cited by 13 publications

(9 citation statements)

References 6 publications

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“…Recent research [23][24][25] derived a numerical index for the sharpness of a blade edge which does not depend explicitly on the blade geometry or the stiffness or strength of the tissue being cut. This approach appears to provide quantitative results that are more consistent than previous attempts to characterise the cutting quality of a knife in terms of either maximum cutting force [26][27][28], the radius of the cutting edge [29][30][31], or the power [32] or energy [33] used during cutting. The definition of a dimensionless index for sharpness usefully permitted different combinations of blades and skin simulants to be compared directly in a quantifiable manner.…”

Section: Introductionmentioning

confidence: 63%

Measuring knife stab penetration into skin simulant using a novel biaxial tension device

Gilchrist

Keenan

Curtis³

et al. 2008

Forensic Science International

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This paper describes the development and use of a biaxial measurement device to analyse the mechanics of knife stabbings. In medicolegal situations it is typical to describe the consequences of a stabbing incident in relative terms that are qualitative and descriptive without being numerically quantitative. Here, the mechanical variables involved in the possible range of knife-tissue penetration events are considered so as to determine the necessary parameters that would need to be controlled in a measurement device. These include knife geometry, in-plane mechanical stress state of skin, angle and speed of knife penetration, and underlying fascia such as muscle or cartilage. Four commonly available household knives with different geometries were used: the blade tips in all cases were single-edged, double-sided and without serrations. Appropriate synthetic materials were used to simulate the response of skin, fat and cartilage, namely polyurethane, compliant foam and ballistic soap, respectively. The force and energy applied by the blade of the knife and the out of plane displacement of the skin were all used successfully to identify the occurrence of skin penetration. The skin tension is shown to have a direct effect on both the force and energy for knife penetration and the depth of out of plane displacement of the skin simulant prior to penetration: larger levels of in-plane tension in the skin are associated with lower penetration forces, energies and displacements. Less force and energy are also required to puncture the skin when the plane of the blade is parallel to a direction of greater skin tension than when perpendicular. This is consistent with the observed behaviour when cutting biological skin: less force is required to cut parallel to the Langer lines than perpendicularly and less force is required to cut when the skin is under a greater level of tension. Finally, and perhaps somewhat surprisingly, evidence is shown to suggest that the quality control processes used to manufacture knives fail to produce consistently uniform blade points in knives that are nominally identical. The consequences of this are that the penetration forces associated with nominally identical knives can vary by as much as 100%.

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Section: Introductionmentioning

confidence: 63%

Measuring knife stab penetration into skin simulant using a novel biaxial tension device

Gilchrist

Keenan

Curtis³

et al. 2008

Forensic Science International

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“…Studies by Thacker et al [36] and Watkins et al [37] on the measurement of sharpness for needles used in surgical procedures utilised force measurement method involving the penetration of simulated tissue. Needles tested in this research are curved and not all have similar radii of curvature.…”

Section: Quantitative Analysis Of Sharpnessmentioning

confidence: 99%

Cutting sharpness measurement: a critical review

Reilly

McCormack

Taylor

2004

Journal of Materials Processing Technology

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“…The sharpness of a cutting instrument is a fundamentally important parameter in all cutting applications because it strongly influences the forces generated and hence energy required during the cutting process, as well as the life of the cutting edge, and surface finish or quality of the cut surface. A number of studies in diverse areas such as general surgery [1][2][3], forensic medicine [4][5][6][7][8], meat processing [9][10][11][12][13], zoology [14][15] and cutting tool evaluation [16] have loosely used the term sharpness to describe the performance of a cutting instrument. However, in these studies the definition of blade sharpness differs significantly.…”

Section: Introductionmentioning

confidence: 99%

On the sharpness of straight edge blades in cutting soft solids: Part I – indentation experiments

McCarthy

Hussey

Gilchrist

2007

Engineering Fracture Mechanics

135

107

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The sharpness of a blade is a key parameter in cutting soft solids, such as biological tissues, foodstuffs or elastomeric materials. It has a first order effect on the effort, and hence energy needed to cut, the quality of the cut surface and the life of the cutting instrument. To date, there is no standard definition, measurement or protocol to quantify blade sharpness. This paper derives a quantitative index of blade sharpness via indentation experiments in which elastomeric materials are cut using both sharp and blunt straight edge blades. It is found that the depth of blade indentation required to initiate a cut or crack in the target material is a function of the condition or sharpness of the blade's tip, and this property is used to formulate a so-called "blade sharpness index" (BSI). It is shown theoretically that this index is zero for an infinitely sharp blade and increases in a quadratic manner for increasing bluntness. For the blades tested herein, the sharpness index was found to vary between 0.2 for sharp blades and 0.5 for blunt blades, respectively. To examine the suitability of the index in other cutting configurations, experiments are performed using different blade types and target materials and it is found that the index is independent of the target material and thus pertains to the blade only. In the companion Part II to this paper a finite element model is developed to examine the effect of blade geometry on the sharpness index derived herein.

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Biomechanical performance of cutting edge surgical needles

Cited by 13 publications

References 6 publications

Measuring knife stab penetration into skin simulant using a novel biaxial tension device

Measuring knife stab penetration into skin simulant using a novel biaxial tension device

Cutting sharpness measurement: a critical review

On the sharpness of straight edge blades in cutting soft solids: Part I – indentation experiments

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