ROBOTIC SYSTEMS FOR SURGICAL APPLICATIONS

Transcription

1 Proceedings of the Interntionl Conference on Mnufcturing Systems ICMS Vol. 4, 2009, ISSN University POLITEHNICA of Buchrest, Mchine nd Mnufcturing Systems Deprtment Buchrest, Romni ROBOTIC SYSTEMS FOR SURGICAL APPLICATIONS Adrin Florin NICOLESCU, Eugen Rdu STRĂJESCU, Andrei-Mrio IVAN, Rolnd KADAR Astrct: This pper presents survey of vrious solutions regrding rootic implementtion in surgicl ppliction. The pproch re sed on severl common concepts of ssisted rootic surgery, however, for ech one numer of prticulrities hve een highlighted in order to provide ckground for further reserch in this re. Afterwrds, the pper illustrtes uthors pproch for rootic surgery system design, y illustrting the development of complete, functionl system sed on four suspended rootic rms crrying surgicl instruments nd one dditionl rm supporting remote controlled lighting lmp. The roots re controlled y two opertors, while the process is supervised y nother three ssistnts. Key words: medicl root, ssisted rootic surgery, mster system, suspended rootic rms, remote control. 1. INTRODUCTION The roots re the first tools in history tht re designed not only to help humns in certin ctivities, ut to replce them entirely in some spects. Although this gol is fr from eing reched, these mchines re used tody in more types of pplictions thn ever, requiring only miniml level of humn supervision. The min reson for which roots re gining more nd more ground in vrious modern ctivities resides in their verstility. Their vrious rchitecturl structures re chrcterized y high moility, llowing the rootic systems to hve very generous working spce, especilly when externl xes re used. Also, due to progrmming flexiility, much more cpilities of prmeter customiztion nd feedck re ville, mking roots more suitle for different sensoril systems implementtion [1]. The ove mentioned spects re coming in ddition to the dvntges tht every mchine hs over humn workers: higher precision, improved repetility nd productivity. These re the min rguments for which the roots re used frequently even in non-industril pplictions, such s surgicl interventions. The min reson for which the roots re widely used in vrious medicl pplictions is tht, when it s out humn helth, ny mistke cn hve very grve consequences. Since the eginning, the medicl roots were intended to drmticlly reduce the error proility nd to extend the surgicl limits eyond the conventionl limits. Trditionlly, one of the min hurdles in medicine ws the low precision of the humn rm. Even with the continuously development of the medicl tools, these were still driven y the hnd of surgeon, which ws suject to stress, tiredness, nd vrious unpredictle events. Typiclly, mn cnnot mintin high levels of concentrtion for extended periods of time, n importnt spect if considering tht some surgicl opertion cn tke well over eight hours to complete. The roots re relile solutions to overcome these issues. But, unlike the industril pplictions, the surgicl processes re not predictle, nor repetitive, so tht the rootic systems cnnot rely solely on their progrmming to successfully perform opertions on humns. A humnmchine interfce is needed in order to llow surgeons fst nd esy control over the roots without ny physicl contct. In the lst twenty yers, the emerging of virtul relity technologies leded to the development of prticulr ctegory of humn controlled systems: remote controlled roots. This concept hs ecome the centrl ojective in rootic medicl systems reserch. One of the min dvntges of medicl roots is their high precision. However, compred to the humn rm, the mechnicl systems provide low flexiility. A solution to this issue consists of complex structures comprised of multiple root rms with redundnt degrees of freedom in order to chieve incresed dexterity nd to void singulrities. Another solution is hptic technology implementtion, which represents method interfces to the user vi the sense of touch y pplying forces, virtions, nd motions [3]. 2. A COMPARATIVE STUDY OF SEVERAL ROBOTIC SURGERY SYSTEMS 2.1. Rootic surgery system sed on roots fixed on the floor Figure 1 illustrtes rootic system tht performs medicl opertions on ptient lying in n pproprite position on tle (this solution is in fct representtion of the D Vinci system developed y Intuitive Surgicl Inc.). The humn opertor (usully surgeon) is conducting minimlly invsive procedure (for exmple lproscopy) mnipulting the hndles of commnd console. According to opertor s ctions, microprocessor is controlling the movement of the endoscopic instruments or other possile ccessories [4].

2 30 Fig. 1. Rootic surgery system sed on root fixed on the floor: ) perspective view; ) ove view; 1 overll lyout; 2 hndles; 3 commnd console; 4 console microprocessor; 5,5 surgicl instruments; 6 rootic system; 7, 9 rootic rms; 8, 10 end effector orienttion system; 11 video cmer; 12 console monitor; 14 centrl monitor; O humn opertor (surgeon); A humn ssistnt; T tle. A typicl lyout of the rootic system comprises of two rootic rms for positioning nd orienting the surgicl tools nd n rm used to mnipulte n endoscopic video cmer for stereoscopic imge cquisition. The imges re simultneously displyed on the console s screen nd on centrl monitor tht llows n ssistnt to supervise the opertion. The ssistnt lso hs the role to perform preliminry positioning of the rootic rms with respect to the ptient nd to chnge the endeffectors. The specific lyout of the surgicl rootic system cn vry ccording to the ppliction, ut common solution is the DVinci root developed y Intuitive Surgicl Inc [5]. The DVinci modulr root is surgicl system designed to fcilitte complex surgery using minimlly invsive pproch. It is used especilly for lproscopy, prosttectomy, crdic vlve repir nd gynecologic procedures. As shown in Fig. 2, the root is comprised of two elements: the positioning system nd the surgicl Fig. 2. The DVinci modulr root: ) generl lyout; ) the positioning system. rootic rms. The positioning system hs SCARA-type generl rchitecture with multiple rms, nd is ttched to moile trolley. Through severl specil linking elements, surgicl root is ttched to ech of the positioning. The surgicl root is ctully prllelogrm mechnism which cn e rotted with roll-type motion, nd it mnipultes n end-effector with the role to hold the surgicl instrument. The numer of rms included in the rootic system my vry, ut n overloded mechnicl structure my crete visiility nd mnipultion prolems. A prtil solution of this issue is the implementtion of n uxiliry device with n dditionl rootic rm (s shown in Fig. 3). The overll system is functioning similrly to the one previously presented. The difference is tht, in this cse, two opertors re needed: one tht controls the min surgicl root nd one tht controls the uxiliry root. The uxiliry device implemented in Fig. 3 cn tke the form of trolley crrying one or more dditionl rootic rms, mnipulted y n ssistnt through supplementry commnd sttion.

3 31 Fig. 3. Rootic surgery system sed on root fixed on the floor nd n uxiliry device including n dditionl rootic rm. The need of using multiple surgicl instruments t the sme time in certin pplictions, while moile imge cquisition system is required, hs led to lterntive solutions, such s using two prllel-operting roots. The system presented in Fig. 4 is similr with tht from Fig. 3, the only difference eing tht, insted of the uxiliry trolley, nother complete D Vinci root is used. The system includes totl of six rootic rms, one of the roots eing mnipulted y the opertor nd the other y n ssistnt. As n exmple of ppliction for this system, one root cn mnipulte two surgicl instruments nd n endoscopic video cmer, while the other root cn mnipulte stilizer nd nother two surgicl instruments (or surgicl instrument nd n endoscopic cmer). Thus, the opertor nd the ssistnt cn cooperte to perform n opertion with stilized hertet or other procedures in which root is holding two prts of tissue nd the other is performing stitch. Nevertheless, such system is still overloding the spce surrounding the ptient ecuse of the multiple rootic rms used. Another pproch regrding ground roots used in surgery is represented y mechnisms tht re mounted on specil type of supports ttched directly to the surgicl tle. This solution llows the rootic rms to retrct under the tle when not operting, freeing the spce round the ptient if intervention from the opertors is required. Fig. 5 illustrtes this pproch with one rm oriented towrds the ptient s domen, while Fig. 5 shows two rms oriented towrds the ptient s torso. Fig. 4. Rootic surgery system sed on two roots fixed on the floor: ) perspective view; ) ove view. Fig. 5. Rootic surgery modulr system sed on two rootic rms ttched to the surgicl tle: ) the rms oriented towrds the ptient s domen; ) the rms oriented towrds the ptient s torso.

4 Rootic surgery modulr system sed on four rootic rms fixed on the ceiling Certin pplictions such s complex lproscopy require numer of severl surgicl tools. Considering the disdvntges of previously illustrted solutions, modulr system ws developed including four suspended rootic rms nd the possiility of dding two or more uxiliry rms fixed on the floor. This comined solution provides n optiml usge of the working spce, llowing efficient coopertion of the surgicl tools. Fig. 6 illustrtes the four suspended rootic rms grouped in two pirs plced on the opposed sides of the surgicl tle. It cn e oserved tht the positioning mechnisms hve prllelogrm structure. Fig. 6 shows the system in operting configurtion, while Fig. 6 shows n ove view of the system. This concept llows the opertors full ccess to the surgicl tle nd its surrounding re [6] A rootic system tht includes offset rotry joints nd rottion correction mechnisms Another pproch ws developed y the Ntionl Aerospce Lortory of Jpn for vrious pplictions, including surgery. The generl rchitecture of this rootic rm is presented in Fig. 7, with two vrints, the difference eing the ngles etween the numericl controlled xes. Fig. 7. Rootic system with offset rotry joints: ) first vrint; ) second vrint. The sis is connected with the first element y conventionl rotry joint, while the next joint hs the xis inclined t different ngle. The third segment of the rootic rm is linked to the second through rottion correction element, solution tht is lso used etween the third nd the fourth segments. The min chrcteristic of this kind of system is tht ll the degrees of freedom re chieved through rotry joints. A degree of freedom is ensured y two ssocited rotry joints, of which one hs the xis inclined with respect to the other one. Both joints cn e driven y the sme motor, so tht plne movement cn e chieved esily, or they cn e driven y two motors for more complex trjectories. The ngles etween the joint xes re chosen in the design phse of the system development ccording to the surgicl ppliction in which the roots will e implemented A rootic system tht includes rotry joints with perpendiculr xes This type of root cn operte in lrge spce, eing driven y smll commnd movements. The implementtion of secondry system for generl coordintes trnsformtion is necessry to llow the opertor to commnd the slve root (providing the required scling etween the slve nd the mster roots). The mster root cn contin the control function of the system so tht singulrity cn e voided for oth roots. The generl lyout of this type of root is presented in Fig. 8. Fig. 6. Rootic surgery modulr system sed on four suspended rootic rms: ) operting configurtion; c) ove view. Fig. 8. A rootic system tht includes rotry joints with perpendiculr xes.

5 33 Fig. 9. Positioning system for suspended rootic system. Fig. 11. Scheme of the developed rootic surgicl system. Fig. 10. End-effector orienttion system A suspended rootic system tht includes positioning system nd n orienttion system The positioning system for this type of root is composed of two turning prllelogrm mechnisms which cn execute horizontl rotry movements or verticl movements (see Fig. 9). The verticl movement is counter-lnced y two springs with force tht cn e djusted y screw-nut system. A retrcted position cn e configured to llow the rm to cler the re surrounding the surgicl tle. The structure stiffness cn e improved y dditionl structurl elements. The end-effector orienttion system is illustrted in Fig. 10. The end-effector is mounted on support ttched to sliding joint. The support llows electriclly ctuted surgicl tools tht require feedck from the opertion re. The end-effector cn perform roll nd sliding movement, s well s rottion provided y prllelogrm mechnism so tht the chrcteristic point of the tool doesn t chnge its position. 3. PRELIMINARY CONCLUSIONS The systems presented ove re intended to provide vrious options to override the issues of rootic surgery, s well s solid ckground for further reserch in this re. Bsed on the ctul development sttus of the rootic medicl systems nd dopting severl solutions presented ove, the uthors hve developed concept tht will comine the dvntges of the existing pproches. The system is sed on four rootic rms suspended on two gntry systems, with one dditionl rm crrying remote operted lighting lmp to provide video feedck of the opertion. The roots re controlled y two opertors, while the process is supervised y nother three ssistnts. The conceptul scheme of the system is illustrted in Fig. 11 [2]. 4. THE BASIC CONCEPTS OF THE PRESENTED ROBOTIC SURGICAL SYSTEM The developed solution is modulr surgicl system sed on multiple suspended rootic rms. This pproch llows multiple surgicl tools mnipultion while, t the sme time, it sves importnt spce round the tle, mking esier for the opertors to closely supervise nd coordinte the opertion. The generl structure chosen for the developed system is illustrted in Fig. 12. It includes four modulr rootic rms suspended on gntry structure which offer them the possiility to slide ove the surgicl tle [1, 3, 4]. The surgicl tools re stored ner the tle, inside the working spce of the roots. Two commnd sttions re seprted from the operting re y sfety trnsprent wll. These consoles llow the surgeons to supervise the process nd to mke decisions in criticl moments. 5. THE COMPLETE LAYOUT OF THE DEVELOPED ROBOTIC SURGICAL SYSTEM After n extended nlysis of the sic structure presented ove, nd considering the specific issues nd requirements of the ppliction, detiled lyout of the rootic cell hs een developed (see Fig. 13) [2]. For incresed precision, the surgicl roots hve een ttched to four corresponding positioning roots with prllelogrm configurtion. The rootic rms re controlled from the commnd posts y two surgeons. The opertion is ttended y three ssistnts: the first ssistnt is usully surgeon, tht stnds eside the surgicl tle nd is directly supervising the process; he is usully the only one who hs direct, close visul contct with the opertion, nd lso chnges the surgicl tools in certin situtions; he cn lso visulize the process on monitor, for etter coordintion with the other opertors; the second ssistnt stnds ner the tool storge tle nd hnds the necessry surgicl instruments to the first ssistnt if he needs to chnge n end-effector,

6 34 c c Fig. 12. The sic lyout of the presented rootic surgicl system: ) perspective view; ) ove view; c) side view; 1 rootic rms; 2 surgicl tle; 3 surgicl tools; 4 commnd posts; 5 gntry structure. or is performing the replcement himself in some situtions; the third ssistnt performs the nesthesi of the ptient. The surgicl tle hs structure with few degrees of freedom in order to set n pproprite height or to llow the orienttion of the ptient in certin positions. The necessry mount of light is provided y lmp mnipulted y n uxiliry rootic rm [5]. In Fig. 14 n lterntive solution is presented, in which two of the four rootic rms re plced on support system ttched to the surgicl tle [6]. This pproch llows the two remining suspended rms etter movement possiilities, since they re using seprte slides for trnsltion. The disdvntge is tht, lthough the two rms mounted on the ground cn e retrcted under the surgicl tle when not operting, they re still tking some spce round the ptient during surgery, possily interfering with the opertors supervision or movements. Fig. 13. The complete lyout of the presented rootic surgicl system: ) perspective view; ) front view; 1 gntry system; 2 positioning rootic rms; 3 surgicl roots; 4 surgeons; 5 control posts; 6 first ssistnt; 7 second ssistnt; 8 uxiliry disply; 9 surgicl tle; 10 nesthetist; 11 ptient; 12 nesthetist s control post; 13 lighting rootic rm; c) side view; d) ove view; 1 gntry system; 2 positioning rootic rms; 3 surgicl roots; 4 surgeons; 5 control posts; 6 first ssistnt; 7 second ssistnt; 8 uxiliry disply; 9 surgicl tle; 10 nesthetist; 11 ptient; 12 nesthetist s control post; 13 lighting rootic rm. d

7 35 A comprtive nlysis hs een mde regrding the driving pproch for the orienttion rotry joints. In Fig. 16, pinion powered y n electricl motor is simultneously rotting oth segments of the rm in contrry direction. The resulting trjectory is plne movement with n ngle smller thn the ngle etween the xes of the two rotry joints. This ehvior is similr with tht of simple rotry joint, the only dvntge eing tht this solution llows greter lod cpcity (however, this is not necessry for surgicl root) [5]. A second pproch is presented in Fig. 17, in which the third element cn e rotted round its inclined xis, round the first rotry joint or it cn execute plne movement. The movement is trnsmitted from the motor to spindle through elt system. The cinemtic flexiility is otined through n electromgnetic device. Fig. 14. An lterntive pproch with two root rms plced on support system ttched to the surgicl tle: ) generl view; ) detil. 6. THE STRUCTURE OF THE ROBOTIC ARM INCLUDED IN THE SURGICAL SYSTEM The generl lyout of the developed rootic rm is illustrted in Fig. 15. The root is suspended on gntry structure, with the sis ttched to trnsltion joint. The mechnicl structure includes positioning system (with two prllelogrm mechnisms) nd n orienttion system (with offset rotry joints) [4]. c Fig. 15. The suspended surgicl root. Fig. 16. An pproch for the orienttion system: ) generl view; ) detiled view; c) the movement of the rotry joints.

8 36 Fig. 17. The second pproch for the orienttion system. Fig. 19. The virtul model of the orienttion system: ) generl view; ) section. Fig. 18. The pproch chosen for the surgicl rootic rm. Although the second pproch hs the chrcteristics required for surgicl pplictions (especilly dexterity nd flexiility), the implementtion of the electromgnetic device leds to very complex mechnism. This is the reson for which the finl solution integrted in the developed surgicl system hs the two rotry joints of the orienttion system driven y seprte motors. The motors re plced grouped t the eginning of the rm, or directly in the ctuted joints, s shown in Fig. 18. The virtul model developed for the orienttion system is illustrted in Fig. 19. The orienttion system is ttched to positioning system composed of two prllelogrm mechnisms (see Figs. 20 nd 21). This structure hs een chosen ecuse it llows the root to cler the re surrounding the surgicl tle, so tht the opertors cn hve free ccess to the ptient. The end-effector cn perform roll-type rottion, ut lso sliding movement, s shown in Fig. 22. A ll ush device is used for movement trnsmission. Fig. 23 illustrtes severl end-effectors tht cn e used in surgicl pplictions. The instrument used in the developed ppliction is presented in Fig. 24. In order to nlyze more efficiently the positions, speeds nd ccelertions of the mechnicl structure elements, the positioning system nd the orienttion system hve een nlyzed seprtely. The inertil d grvittionl lods hve een determined y pproximting model of the root sed on the existing documenttion. Fig. 20. Fist prt of the virtul model of the positioning system: ) generl view; ) 5 th nd 4 th xes.

9 37 Fig. 23. End-effectors used in surgicl pplictions. Fig. 21. Second prt of the virtul model of the positioning system: ) 3 rd nd 2 nd xes; ) first xis. Fig. 24. The end-effector used in the developed ppliction: ) generl view; ) sections. Fig. 22. The trnsltion movement of the end-effector. In order to determine the most unfvorle configurtion, the lods hve een clculted for two different positions of the rootic rm (the gretest lods hve een considered).

10 38 7. CONCLUSIONS Since the eginning, the medicl roots were intended to drmticlly reduce the error proility nd to extend the surgicl limits eyond the conventionl limits. The most importnt spects of this pproch in medicl pplictions re precision, minituriztion, smller incisions, decresed lood loss, less pin nd quicker heling time. These rguments re solid justifictions for continuous reserch in rootic medicl systems, ttempting to find new solutions to overcome specific issues. The introduction of utomted systems (especilly rootic cells) in surgicl pplictions llowed the development of specific techniques, such s remote nd unmnned surgery, minimlly invsive surgery nd hptic control of medicl systems. This pper presents fully developed rootic surgicl system tht is cple of miniml invsive nd precise opertions. The implementtion of virtul relity technology llows the rootic rm to e remote controlled y surgeons, which hve full control of the process. The rchitecture of the system llows full moility of the mnipultors, while keeping the spce round the surgicl tle cler. This chrcteristics offer mximum ccess to the ptient for oth the rootic rms nd the opertors, efficiently comining the mechnicl nd the humn fctors. REFERENCES [1] Nicolescu, A. (2009). Industril Roots Implemented into Rootic Mnufcturing Systems (Work in progress, in Romnin), Edit. Didctică şi Pedgogică. [2] Kdr, R. (2007). Rootic system for surgicl pplictions, diplom work, University "Politehnic" of Buchrest. [3] Nicolescu A., Mohor C., Ivn A. (2009). Root for medicl pplictions (Work in progress, in Romnin), Edit. Didctică şi Pedgogică. [4] Blumenkrnz, S., Ros, D. (2002). Mnipultor positioning linkge for rootic surgery, ville t ccessed: [5] Tierney, M., Cooper, T. (2002). Mechnicl ctutor interfce system for rootic surgicl tools, ville t ccessed: [6] Blumenkrnz, S. (2005). Ceiling nd floor mounted surgicl root set-up rm, ville t ccessed: Authors: PhD, Eng., Adrin Florin NICOLESCU, Professor, University "Politehnic" of Buchrest, Deprtment of Mchines nd Mnufcturing Systems, E-mil: fnicolescu@yhoo.com, PhD, Eng., Eugen Rdu STRĂJESCU, Professor, Poli- University "Politehnic"of Buchrest, Deprtment of Mchines nd Mnufcturing Systems, E-mil: eugen_strjescu@yhoo.com, Eng, Andrei-Mrio IVAN, PhD Student, University "Politehnic" of Buchrest, Deprtment of Mchines nd Mnufcturing Systems, E-mil: ndrei.mrio@yhoo.com, Eng, Rolnd KADAR, PhD Student, University "Politehnic" of Buchrest, Deprtment of Mchines nd Mnufcturing Systems, E-mil: rolndkdr@gmil.com.