Kidney stones in the human urinary system has become a notable problem with high levels of diffusion in most of the western world and in Italy. Several technological solutions have been developed over the years for the treatment of this pathology. In recent years the most widespread technique recommended by urologists is flexible urethroscopy. It is a minimally invasive technique which consists in inserting a surgical instrument (ureteroscope) through natural orifices, in this case the urethra, to reach the deepest parts of the urinary system (ureters and kidneys) where the kidney stones are located. Ergonomics and postural problems have been found in surgeons who exploit this technique in everyday work, creating ailments and permanent injuries in clinicians. Thanks to the development of surgical robotics, solutions have been developed that involve the control of the ureteroscope through a robotic system. The LITHOS project, where this master’s thesis is framed, involves the development of a robotic control system for a commercial ureteroscope, with the aim of solving the ergonomic problems encountered and favouring the diffusion of this promising technique. The main purpose of this work is to design and implement a prototype robotic system for the control of an ureteroscope, which allows the surgeons to remotely operate in a comfortable position without the risk of muscle injuries and exposures to radiation. During this MSc Thesis, the author has designed, developed and implemented the mechanical design to attach to the ureteroscope, configured the hardware to be connected to the motors that attached to the mechanical parts, implemented the firmware controlling the motors and the software on the computer for the surgeons testing. This system has three degrees of freedom, and every single degree of freedom requires the design of mechanical solutions to control that movement. Furthermore, it was necessary to design a control system for the instrument that could allow the user to perform the movements in an ergonomically advantageous position. The prototype has been designed in all its mechanical and hardware parts and firmware has been developed for the communication between the elements of the device and the data collection. A first graphical interface has also been designed that makes it possible for the user to monitor the performance of the robot. A statistical analysis on the finished prototype was necessary to study the performance and find problems on the implemented technological solutions. In fact, the prototype must comply with some basic specifications, about its range of motion and its precision. The ranges of movement that each degree of freedom can perform, and the precision of these movements have been evaluated. The ureteroscope cable was required to travel the entire urinary system, about 50/55 cm. A range of 51,5 cm was obtained. Furthermore, the instrument had to rotate 360 ° around its longitudinal axis and the lever that controls the movement of the tip must be able to travel 90 °. Values over 360 ° and about 90° have been obtained for these movements. The accuracy is also evaluated for each movement, obtaining values of 0,51 cm for the insertion movement of the endoscopic cable, 0,38 ° for the rotation of the instrument around its own axis, 4,67 ° for the movement of the lever of tip control. Values that can be considered improved or close to the ones achievable with manual control of the instrument. The statistical analysis has also led to the discovery and study of some problems due to the designed mechanical technology.
La presenza di calcoli nel sistema urinario umano è diventato un problema di notevole entità con alti livelli di diffusione in gran parte del mondo occidentale e in Italia. Diverse soluzioni tecnologiche sono state sviluppate nel corso degli anni per la cura e il trattamento di questa patologia. Negli ultimi anni la tecnica maggiormente diffusa e consigliata dagli urologi è la uretroscopia flessibile. Questa è una tecnica mininvasiva che consiste nell’inserimento di uno strumento chirurgico (uretroscopio) attraverso orifizi naturali, in questo caso l’uretra, per raggiungere le parti più profonde del sistema urinario (ureteri e reni) dove si localizzano i calcoli. Problemi ergonomici e posturali sono stati riscontrati nei chirurghi che attuano questo tipo di tecnica nel quotidiano, creando disturbi e lesioni permanenti nel personale sanitario. Grazie allo sviluppo della robotica chirurgica si sono sviluppate perciò soluzioni che prevedono il controllo dell’uretroscopio attraverso un sistema robotico. Il progetto LITHOS, nel quale si colloca questo lavoro di tesi, prevede lo sviluppo di un sistema di controllo robotico per un uretroscopio commerciale, con la finalità di risolvere i problemi ergonomici riscontrati e favorire la diffusione di questa promettente tecnica. Lo scopo principale di questo lavoro è quello di progettare e creare un prototipo di sistema robotico per il controllo di un uretroscopio, che consenta ai chirurghi di operare a distanza e in una posizione comoda, annullando il rischio di lesioni muscolari o esposizioni alle radiazioni. Durante questa tesi di laura, l’autore ha progettato e sviluppato le diverse parti meccaniche che si collegano all’uretroscopio, configurato l’hardware per la gestione dei motori che muovono le diverse parti meccaniche, implementato il firmware che controlla i motori e il software ad uso dell’utente. Questo sistema ha tre gradi di libertà, e ogni singolo grado necessita la progettazione di soluzioni meccaniche per il controllo di quel preciso movimento. Inoltre, si è reso necessario progettare un sistema di controllo per lo strumento che possa consentire all’utente di realizzare i movimenti preposti da una posizione ergonomicamente vantaggiosa. Il prototipo è stato progettato in ogni sua parte meccanica e hardware e si sono sviluppati firmware per la comunicazione tra i vari elementi del dispositivo e la raccolta di dati. Viene inoltre progettata una prima interfaccia grafica che rende possibile all’utente il monitoraggio delle prestazioni del robot. Un’analisi statistica sul prototipo finito è stata necessaria per studiare le prestazioni e riscontrare problemi sulle soluzioni tecnologiche implementate. Il prototipo deve infatti rispettare alcune specifiche base, circa il suo range di movimento e la sua precisione. Sono stati perciò calcolati o stimati i range di movimento che ciascuno grado di libertà può eseguire e la precisione con il quale questi movimenti avvengono. Si richiedeva che il cavo dell’uretroscopio potesse percorrere l’intero sistema urinario, circa 50/55 cm. Un range di 51,5 cm viene ottenuto. Inoltre, lo strumento doveva poter ruotare di 360° intorno al proprio asse e la leva che controlla il movimento della punta deve potere traslare di 90°. Valori oltre i 360° e vicini ai 90° vengono ottenuti per questi movimenti. L’accuratezza inoltre viene valutata per ogni grado di libertà, ottenendo valori di 0,51 cm per il movimento di inserimento del cavo endoscopico, 0,38° per la rotazione dello strumento intorno al proprio asse, 4,67° per il movimento della leva di controllo della punta. Valori che possono ritenersi migliorati o vicini rispetto alla precisione ottenibile con il controllo manuale dello strumento. L’analisi statistica ha portato inoltre alla scoperta e allo studio di alcune problematiche, dovute alla tecnologia meccanica progettata.
Design and implementation of a robotic prototype for the control of a flexible ureteroscope
NASI, FEDERICO
2017/2018
Abstract
Kidney stones in the human urinary system has become a notable problem with high levels of diffusion in most of the western world and in Italy. Several technological solutions have been developed over the years for the treatment of this pathology. In recent years the most widespread technique recommended by urologists is flexible urethroscopy. It is a minimally invasive technique which consists in inserting a surgical instrument (ureteroscope) through natural orifices, in this case the urethra, to reach the deepest parts of the urinary system (ureters and kidneys) where the kidney stones are located. Ergonomics and postural problems have been found in surgeons who exploit this technique in everyday work, creating ailments and permanent injuries in clinicians. Thanks to the development of surgical robotics, solutions have been developed that involve the control of the ureteroscope through a robotic system. The LITHOS project, where this master’s thesis is framed, involves the development of a robotic control system for a commercial ureteroscope, with the aim of solving the ergonomic problems encountered and favouring the diffusion of this promising technique. The main purpose of this work is to design and implement a prototype robotic system for the control of an ureteroscope, which allows the surgeons to remotely operate in a comfortable position without the risk of muscle injuries and exposures to radiation. During this MSc Thesis, the author has designed, developed and implemented the mechanical design to attach to the ureteroscope, configured the hardware to be connected to the motors that attached to the mechanical parts, implemented the firmware controlling the motors and the software on the computer for the surgeons testing. This system has three degrees of freedom, and every single degree of freedom requires the design of mechanical solutions to control that movement. Furthermore, it was necessary to design a control system for the instrument that could allow the user to perform the movements in an ergonomically advantageous position. The prototype has been designed in all its mechanical and hardware parts and firmware has been developed for the communication between the elements of the device and the data collection. A first graphical interface has also been designed that makes it possible for the user to monitor the performance of the robot. A statistical analysis on the finished prototype was necessary to study the performance and find problems on the implemented technological solutions. In fact, the prototype must comply with some basic specifications, about its range of motion and its precision. The ranges of movement that each degree of freedom can perform, and the precision of these movements have been evaluated. The ureteroscope cable was required to travel the entire urinary system, about 50/55 cm. A range of 51,5 cm was obtained. Furthermore, the instrument had to rotate 360 ° around its longitudinal axis and the lever that controls the movement of the tip must be able to travel 90 °. Values over 360 ° and about 90° have been obtained for these movements. The accuracy is also evaluated for each movement, obtaining values of 0,51 cm for the insertion movement of the endoscopic cable, 0,38 ° for the rotation of the instrument around its own axis, 4,67 ° for the movement of the lever of tip control. Values that can be considered improved or close to the ones achievable with manual control of the instrument. The statistical analysis has also led to the discovery and study of some problems due to the designed mechanical technology.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/146265