A novel puborectalis muscle artificial anal sphincter system with the module of sensory perception

Wu, Hao; Wang, Zhiwu; Yan, Guozheng; Jin, Wentian; Lü, Shan; Zhou, Zerun

doi:10.1080/03091902.2016.1226438

Cited by 3 publications

(1 citation statement)

References 17 publications

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“…However, in prior in vivo experiments, it was shown that hyperplasia wrapped the nylon-12 rotatable arm and caused mechanical failure, approximately 2 months after implantation. [5][6][7][8][9] Thus, although the PAAS improves many defects which occurred in previous AAS systems, it is limited by the influence of hyperplasia. Accordingly, there are still obstacles in the application of the system in clinical practice.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of hyperplasia during the implantation of the puborectalis-like artificial anal sphincter

et al. 2020

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Objectives: This study aims to extend the implantation lifetime of the puborectalis-like artificial anal sphincter by inhibiting the occurrence of hyperplasia following the implantation process. Method: A new transmission structure was designed inside the puborectalis-like artificial anal sphincter to generate an adequate torque to maintain the feces, even if hyperplasia developed around the prosthetic sphincter. An outer shell was added to the prosthetic sphincter to decelerate the occurrence of hyperplasia on the outer shell side. Medical titanium alloy was tested to replace the nylon-12 prosthetic sphincter, while polyetheretherketone was used for the construction of the power supply unit in the puborectalis-like artificial anal sphincter system instead of nylon-12. In vivo experiments were conducted to evaluate all the methods presented in this study with 10 Pa Ma piglets, 1 domestic pig, and 1 beagle dog during the past 2 years. Results: Compared with the previous prosthetic sphincter that was equipped with a fixed-axle gear transmission, the new transmission structure is equipped with a planet-gear train managed to generate a prosthetic sphincter output with a 53% larger torque but with the same size and type of motor as that used previously and increase the implantation lifetime by 56%. After the replacement of the nylon-12, the new prosthetic sphincter made of medical titanium alloy succeeded in extending the implanted lifetime by 83%. In addition, the lifetime was increased by 143%, when an outer shell was added to the prosthetic sphincter. Polyetheretherketone significantly decreased the growth rate of hyperplasia around the power supply unit by 44% after the replacement of the power supply unit material. After the combination of all the improvements, the longest implantation lifetime of the puborectalis-like artificial anal sphincter during the in vivo experiments was 7 months and 10 days, which reflected an improvement of 249%. Conclusion: All methods posted in this study were evaluated to be effective to prolong the implantation lifetime of the puborectalis-like artificial anal sphincter. Among the methods proposed, the most effective was the addition of the outer shell to the puborectalis-like artificial anal sphincter. The least effective method was the improvement of the transmission structure. Medical titanium alloy and polyetheretherketone were good replacements for nylon-12 that managed to extend the implantation lifetime and yield a moderate improvement.

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Section: Introductionmentioning

confidence: 99%

Inhibition of hyperplasia during the implantation of the puborectalis-like artificial anal sphincter

et al. 2020

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Comparative analysis of occlusion methods for artificial sphincters

et al. 2020

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An artificial sphincter is a device that replaces the function of the biological sphincter by occluding the relative biological lumen. The investigation of occlusion methods for artificial sphincters is crucial for a reliable and effective design of such devices. The compression induced onto the tissue by a certain pressure depends on the biomechanical and physiological features of the lumen and on the specific occlusion method. A numerical model and an experimental evaluation are presented here to assess the efficiency of different occlusion methods. Numerical models of circumferential occlusion and clamping occlusion methods to simulate the compression of the biological lumen were developed. Results revealed a relationship between the efficiency of the occlusion method and the physiological condition of the lumen. With differences related to the testing setup, this relationship was also confirmed experimentally by conducting tests on biological simulators. We analyzed the occlusion method to adopt as the physiological pressure (ie, leakage pressure values) changed. In particular, we focused on the urinary incontinence, which is a dysfunction involving the external sphincter surrounding the urethra. In this scenario, we demonstrated that a clamping occlusion is an efficient method to compress the urethra, whose physiological pressures range between 4 and 12 kPa. The clamping occlusion method resulted up to 35% more efficient in terms of sealing pressure than the circumferential one for a closing pressure varying between 2.3 and 11.5 kPa.

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Design, Improvement and Evaluation of a Novel In Situ Implanted Bionic Artificial Anal Sphincter

Wang

Yan

Ding

et al. 2022

Journal of Medical Devices

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Artificial anal sphincter has gradually become an emerging means of treating anal incontinence. However, most of the systems cannot be implanted in the human body for a long time due to insufficient reliability. Therefore, this paper has designed and improved a novel bionic artificial anal sphincter (BAAS). In order to make it work reliably for a long time, we first optimized and improved key parts to increase their strength. Given the humid working environment in the body, we optimized the design of the waterproof pressure sensor and carried out experimental research on the sealing of the circuit board and the overall sealing. When evaluating the improved system, I used simulation to analyze the structural strength and motion characteristics of the BAAS and used underwater experiments to simulate the human environment to evaluate the waterproofness of the system. The results showed that the strength of the key joint increased by 49.4%, the average clamping time and opening time of the prosthesis were 14.5s and 13.4s, respectively, and the angular velocity of the pendulum rod approaching the intestine was about 4.5°/s, which was in line with the normal defecation process of the human body. The performance is stable and reliable in the 20-day underwater body fluid simulation experiment. BAAS basically meets the application needs of long-term implantation in the treatment of fecal incontinence.

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A novel puborectalis muscle artificial anal sphincter system with the module of sensory perception

Cited by 3 publications

References 17 publications

Inhibition of hyperplasia during the implantation of the puborectalis-like artificial anal sphincter

Inhibition of hyperplasia during the implantation of the puborectalis-like artificial anal sphincter

Comparative analysis of occlusion methods for artificial sphincters

Design, Improvement and Evaluation of a Novel In Situ Implanted Bionic Artificial Anal Sphincter

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