Design and development of a detrusor system for artificial bladder

The urinary bladder is indispensable to collect urine and void upon peripheral nervous system control. However, cancer, neurological disorders and aging can cause a loss in bladder functions. To date, the existing solutions are only partial and disabling in some cases, thus result in a reduced patients quality of life. The present work aims at developing a fully implantable artificial bladder system (ABS) able to store and eliminate urine. The proposed system is a bicomponent device consisting of an artificial bladder integrated with a hydraulically driven mechanism that serves as detrusor system. The actuation is operated through a controller and a micropumping system connected to a reservoir. The ABS is a self-foldable inextensible structure that can hold 300ml. For the voiding strategy two types of hydraulic actuators are proposed: origami and bellows actuator. The former consists of a rigid zigzag skeleton enclosed in a flexible skin and a fluid medium between them. When a negative pressure is applied by removing the fluid, the actuator contracts exerting a pulling force. The latter one is made of a chain of flexible and inextensible interconnected chambers. They are completely flat when there is no fluid inside but elongate producing a pushing force when inflated. After the design optimization, each actuator type is tested on the ABS and the voiding efficiency is evaluated. The bellows actuators showed higher performance achieving an ABS voiding efficiency of 90%

Hydraulic Detrusor for Artificial Bladder Active Voiding

: The gold standard treatment for bladder cancer is radical cystectomy that implies bladder removal coupled to urinary diversions. Despite the serious complications and the impossibility of controlled active voiding, bladder substitution with artificial systems is a challenge and cannot represent a real option, yet. In this article, we present hydraulic artificial detrusor prototypes to control and drive the voiding of an artificial bladder (AB). These prototypes rely on two actuator designs (origami and bellows) based either on negative or positive operating pressure, to be combined with an AB structure. Based on the bladder geometry and size, we optimized the actuators in terms of contraction/expansion performances, minimizing the liquid volume required for actuation and exploring different actuator arrangements to maximize the voiding efficiency. To operate the actuators, an ad hoc electrohydraulic circuit was developed for transferring liquid between the actuators and a reservoir, both of them intended to be implanted. The AB, actuators, and reservoir were fabricated with biocompatible flexible thermoplastic materials by a heat-sealing process. We assessed the voiding efficiency with benchtop experiments by varying the actuator type and arrangement at different simulated patient positions (horizontal, 45° tilted, and vertical) to identify the optimal configuration and actuation strategy. The most efficient solution relies on two bellows actuators anchored to the AB. This artificial detrusor design resulted in a voiding efficiency of about 99%, 99%, and 89%, in the vertical, 45° tilted, and horizontal positions, respectively. The relative voiding time was reduced by about 17, 24, and 55 s compared with the unactuated bladder

An origami-based hydraulic soft artificial detrusor

Objectives: Neurological and non-neurological disorders (e.g. spinal injuries and detrusor ageing) can impair controlled bladder emptying capabilities. Neural stimulators have been proposed to reactivate the associated neural pathways, but they feature severe long term side effects. Artificial detrusor systems might act as an alternative solution, although sparsely approached by researchers. We propose here a novel hydraulic soft bodied artificial detrusor for controlled bladder voiding. Methods: The artificial detrusor is composed of two semispherical units embracing the natural bladder. They consist of a soft silicon skin enclosing a water chamber and a flexible acetate origami skeleton (waterbomb pattern). The origami guides the shape change from domed to flat when a negative pressure is applied. This shift compresses the bladder allowing the voiding. The voiding performances (bladder volume (Vb), voiding efficiency (VE), post-voiding residual volume (PVR), and voiding time (VT)) were assessed ex-vivo on horizontally oriented porcine bladders (i.e. simulating bedridden patients). The performance was compared with both naked bladder and de-activated detrusor ones to assess the role played by spontaneous voiding and gravity, respectively. Three waterbomb detrusor filling levels were evaluated (120, 140 and 160 mL), to investigate their effect on the skeleton contraction. Results: The proposed detrusor proved an average VE of ~90% and a PVR < 20 mL, irrespective of the detrusor filling degree. When non-actuated, VE and PVR varied between 50-70% and 20-50 mL, respectively. The VT lowers from ~400 s (unactuated) to ~200 s (actuated). The Vb ranges from 75 to 100 mL, depending on the detrusor filling. Conclusions: The proposed system could efficiently restore active voiding also in bedridden patients. Design improvements are required to allow more physiological bladder volumes. Acknowledgements: The authors acknowledge INAIL (Istituto Nazionale Assicurazioni Infortuni sul Lavoro) for providing their collaboration in the framework of the BioSUP project

A Hydraulic Implantable Artificial Detrusor for Controlled Bladder Voiding

Severe spinal cord injuries or detrusor muscle degeneration due to aging can cause the loss of contractility of the urinary bladder. To date, long-term clinical solutions to restore contraction control include neurostimulators with unpleasant long-term side effects. Thus, implantable artificial detrusors turn out to be an urgent promising solution in this field. In this paper, an origami-based fluidic system is proposed as a robotic prosthesis for human bladder voiding. Both on-the-bench and ex vivo tests highlighted promising results with a bladder voiding efficiency range of 75-90%

Awake surgery between art and science. Part I: clinical and operative settings

Awake surgery requires coordinated teamwork and communication between the surgeon and the anesthesiologist, as he monitors the patient, the neuroradiologist as he interprets the images for intraoperative confirmation, and the neuropsychologist and neurophysiologist as they evaluate in real-time the patient’s responses to commands and questions. To improve comparison across published studies on clinical assessment and operative settings in awake surgery, we reviewed the literature, focusing on methodological differences and aims. In complex, interdisciplinary medical care, such differences can affect the outcome and the cost-benefit ratio of the treatment. Standardization of intraoperative mapping and related controversies will be discussed in Part II

Effects of pre‐operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05-1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4-7 days or >= 8 days of 1.25 (1.04-1.48), p = 0.015 and 1.31 (1.11-1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care