Innovative Technologies In Non-Invasive Urodynamics Diagnostic

Nowadays, clinical investigations to understand the functionality of the lower urinary tract (LUT) are based on invasive techniques (e.g. use of catheters) for measuring intra-bladder pressure and flowmetry through urethra. These techniques can lead to significant discomfort and possible complications to patients; moreover, they represent for the health agencies an economic burden in terms of costs associated with supplies, and above all they require a great deal of personnel’s time; finally, current techniques are inadequate for urodynamic analysis in pediatric subjects. This interdisciplinary project intends to verify the possibility to develop an Innovative Instrumentation for non-invasive Urodynamics, that is in which no part of the machine comes in contact with the human body, and moreover it is characterized by the same diagnostic reliability of the techniques in use today. This Innovative Instrumentation can bring many benefits: for the patient, who is relieved of the discomfort related to the traditional methodology, and who takes less time to perform it (15 minutes instead of 60); for the structure that uses this Innovative Instrumentation, which can reduce operating costs both in terms of materials and in terms of personnel. The basic concept arises from considering the LUT similar to a hydraulic system consisting of a pressure feed tank (bladder) and an outlet elastic duct (urethra) whose physical behavior is governed by the laws of fluid mechanics. Starting from the knowledge of the physical quantities of the urinary jet measurable outside of the urethra it is possible to model the LUT internal urodynamic characteristics. A physical model of the LUT has been specifically designed and assembled in the Hydraulic Laboratory of the Department of Civil and Environmental Engineering (DICEA) of the University of Florence: basically, it consists of a pressure feed tank connected to a latex elastic collapsible output tube, that has a similar behavior to the urethra. The model has been tested with experiments to evaluate jet external characteristics under many different conditions (i.e. presence or absence of obstructions, type of obstructions, presence of absence of catheter, different types of instrumentations, etc.). Furthermore, a numerical model of the flow in elastic tube has been developed to simulate the Laboratory experiments and to represent the complex phenomena that occur in the LUT in physiological and pathological conditions. Once the numerical model has been calibrated, the detrusor pressure can be estimated from the values of flow rate and exit velocity obtained by non-invasive measurements, that is measurements taken with no contact with the human body. In parallel, a prototype of the Innovative Instrumentation has been developed. It has been built in the Hydraulic Laboratory of the DICEA and it has been taken to the Urology Clinic at the Department of Experimental and Clinical Medicine (DMSC) of Careggi Hospital, Florence, to perform a clinical testing campaign on healthy male volunteers to test and calibrate the diagnostic reliability of the new equipment. Finally, it is proposed a “Coupled Urodynamic Diagram” that can be used to estimate the detrusorial pressure and that allows to trace the functional status of the patient using only non-invasive data.