Penile compression clamps: A model of the internal mechanical state of penile soft tissues

Abstract

Aims: Prostate cancer is the most frequently diagnosed cancer, and male incontinence represents a major consequence following surgery. Penile compression clamps (PCCs) which externally occlude the urethra, may be used to manage the incontinence. Despite potential complication of PCCs, such as deformation-inflicted tissue damage, to date, there are no reported biomechanical criteria for design of PCCs, in terms of quantitative parameters for evaluating the safety-versus-efficacy of existing or future designs.Methods: we developed a set of computational three-dimensional models of the penis, to which compression was applied using five generic PCC designs. The internal mechanic states of the soft tissues of the penis were then analysed using finite element simulations.Results: Stresses in skin, fat and tunica albuginea regularly exceeded 10 kPa (75mmHg). Cuff-type and knurl-type PCCs pose the highest potential risks to tissue health with elevated tissue stresses around the entire penile perimeter (cuff) or urethral stress concentrations (knurl). The soft and contoured PCCs produced the lowest values of these mechanical parameters. Conclusion:The present study identified design characteristics, being envelopment, adaptability and durability, which provide the safest mechanical conditions in the penis and thus minimize the risk of tissue damage while still managing incontinence. Such data should help to design a safer clamp. Frequent off-loading of the penile tissues should be emphasized to patients, to prevent deformation-inflicted tissue damage. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 To control leakage, men resort to absorbent pads, urinary sheaths, body-worn urinals and penile compression clamps (PCCs). 4,5 Designed to externally occlude the urethra, PCCs have been reported to reduce the impact of incontinence and be particularly useful for managing incontinence during activities. 6,7 However, PCCs do not completely eliminate urine leakage when applied at a comfortable pressure and pain is reported when compression is sufficient to prevent leakage. 5,6 Case reports describe reduced penile blood flow and deformation-inflicted tissue damage, but there is no evaluative data assessing the effect of various penile clamp designs and the real life potential for injury. 8,9 The purpose of this study was to develop a computational model of the internal mechanical state of the penis when compressed by a range of PCC designs. This study is part of a larger programme of work to design an effective, comfortable and low risk PCC. Materials & Methods GeometryTwelve FE model variants (models) were developed, representing five generic designs and three stiffnesses of interface materials representative of PCCs currently available on the internet (see Table 1). Each model was based on an anatomical description of the 3D structure of ...

<p>Tissue response to applied loading using different designs of penile compression clamps</p>

“…A computer model confirms the limitations of current PCD designs and the potential risk of soft tissue damage 17. Interface pressure of 188 mmHg within the range of the present in vivo study (Figure 3) caused internal stresses greater than 75 mmHg in the skin, fat and tunica albuginea proximal to the urethra.…”

Device-related pressure ulcers: SECURE prevention

“…• Devices may generate high stress concentrations in tissues, leading to cell and tissue damage pathways associated with sustained deformation 86,99,100 • Devices intended to alleviate pressure and tissue loads may themselves increase load and thus the risk of DRPU 86 • Insensate patients are especially at risk of localised high-tissue deformation, stresses 96 and stress concentrations • Everyday activities such as toilet sitting increase tissue loads and reduce perfusion 101 and tissue oxygenation, placing individuals with reduced sensory and/or mobility at high risk.…”

Qualitative analysis of Amazon customer reviews of penile clamps for male urinary incontinence

“…21 Discomfort due to bad design or material can cause significant complications including penile incarceration. 22 Increasing efforts have been made to better quantitate this tradeoff between urinary incontinence control and significant discomfort and pain. Using three-dimensional modeling of penile soft tissues, Levy et al 23 identified envelopment, adaptability, and durability as parameters to help guide clamp design.…”