Progress of Surgical Robot in Minimal Invasive Surgery

WU Yang-chun，CHENG Li-ming

Department of Spinal Surgery，Tongji Hospital，Tongji University School of Medicine，Shanghai 200065，China

Progress of Surgical Robot in Minimal Invasive Surgery

WU Yang-chun，CHENG Li-ming

Department of Spinal Surgery，Tongji Hospital，Tongji University School of Medicine，Shanghai 200065，China

It is a hot topic about the development of surgery robot in minimal invasive surgery.Known as the second cohort of robots，ZEUS and Da Vinci have been designed for variant purposes;however，its high cost and huge body obstructs its clinical application.Recent rising small robots that could be adapt to different needs with a lower cost.It is no doubt that robotic surgery has become a main technology in minimal invasive surgery.

Robotic surgery;Computer assisted surgery;Minimal invasive surgery

Introduction

Compared with traditional operation，minimal invasive surgery(MIS)refers to the practices that with lessinvasive butsame purpose.Since all procedures are finished under endoscopes，there are only several small holes left，instead of a multicentimeter incision.Accompanying with the development of endoscopic technology，surgeons just need only one ortwo tiny hole to finish the complicate operation.

Robots assisted surgeries have many advantages compared to the traditional surgery，such as more accurate location，higher efficient surgery，and less tissue damage.In addition，robots assisted surgeries are labor-saving.However，because of the complicated per-surgery planning and programming，the total cost of robots assisted surgeries is dramatically higher than conventional ones.As the development of operation instruments and the maturation of operators’skills，the time of operation is getting shorten.

Terms to operation time，there are many other reasons which may drive surgeons to choose MIS，such as less scarring，less complication，shorter heal duration.But the huge money cost is the major challenge to MIS.Furthermore，it not only needs to improve MIS technology but also requires to give an integrative plan before procedures.

The author will lay emphases on the development and apply of surgery robotics to MIS.

Industrial robots in surgeries

CT-guided brain biopsy was the first recorded robots assisted surgery which was performed on 11th April 1985 attheMemorialMedicalCenterin America.The assistant robot was a Unimation PUMA 200 industrial robot.It was programmed to locate the surgery target with CT guidance［1］.After the target was located，the surgeons could decide a best trajectory in a variety of different ways.And then a stereotaxic instrument which hold PUMA’s guide was locked in position so that a probe could be straightly inserted along the decided trajectory and reached the target region without disturbing other vital structures.When the trajectory was aimed，the biopsy needle was inserted and the tip of the needle hit the target deep in brain.The success showed robots’accuracy，which can avoid unexpected damagecaused by surgeons’mishandling.

Another fantastic surgical robot ensued in 6 years later at Imperial in London.It was the first recorded robot which was used to resect prostate tissue.It was named Probot［2］and its prototype was also Unimate Puma.The procedure fully showed the high efficiency of robots assisted procedure.Operation time was reduced to 5 minutesfrom originalone hour.Importantly，less physicians were required in the procedure.

In 1992，a 5freedom degree robot was manufactured by Sankyo Seiki.Installing with Robodoc system，this novel robot was entered the clinical use for total hip arthroplasty(THA).

From then on，Robodoc system has assisted surgeons in more than 24，000 joint replacement operations across the United States，Europe，Japan，Korea and India.

Besides the Robodoc system，there is another industrial robot operation system called Syberknife system［4］:a robotic radiosugery system.Tumor is killed by radiation whilst minimizing radiation to adjacent tissues.

These industrial robots mentioned above make up the firgt generation of robots which was able to carry out tasks automatically at some stage during procedures without surgeons’direct intervention such as the Probot while some other robots like the one in brain biopsy were used to locate target position，adjust path and lock stably with CT guidance.

Master/slave Robots

Master/slave robots are assistive or collaborative devices.They can follow programmed commands or change them real－timely during procedures and even redo what surgeons are doing simultaneously.Almost all of the master/slave robots can assist MIS.

Aesop Robotic Surgical System［5］was developed in 1994 for holding cameras during procedures.Operators can control its movements by some simple commands such as‘left’‘right’‘up’‘down’，etc.Beside these the simple direction movements，Aesop is also a programmable robot.It can save three preprogrammed locations of the operating field and can return to any of the three locations form a present position by voice command.Compared to holding cameras manually，Aesop’s camera arm moves more smoothly and hold cameras more stably.Thus operators can concentrate on the operating target more easily，which can make mishandling decrease in some degree.

The ZEUS Robotic Surgical System developed in 1996［6］consisting of three interactive robotic arms and a control unit.One robotic arm is used to position the endoscope and the other two robotic arms manipulate surgicalinstruments underthe surgeon's remote control.While seated at the console in a chair with armrests，the surgeon can have either a 3-dimensional or a 2-dimensionalview ofthe operative site，depending on preference.ZEUS robotic system successfully assisted the first cross-Atlantic cholecystectomy in 7thSeptember 2001.

Da Vinci Robotic Surgery system developed in 2000.It has 3 components:a vision cart that holds a dual light source and dual cameras，a master console where the surgeon sits，and a moveable cart，where 2 instrument arms and a camera arm are mounted.The camera arm contains dual cameras whose images can be processed into 3-dimensional ones via an image processing computer in master console.This system displays its 3-dimensional image above the hands of the surgeon so that it gives the surgeon the illusion that the tips of the instruments are an extension of the control grips，thus giving the impression of being at the surgical site［7］.Besides the image processing computer，a master console also has a view port where the surgeon views 3D image which has been enlarged about 10 －15 times bigger than image itself，foot pedals to control electrocautery，cameras，instruments and master control grips that drive the servant robotic arms at patient's side.The instruments are cable driven and provide 7 degrees of freedom.Although Da Vinci system has such fantastic functions but it doesn't have the capability of haptics in its early stage which is the sense of force feedback from the instruments to the surgeon.But recently a computerized force feedback endoscopic surgical grasper has been developed［8］and shows satisfactory performance.

Hansen Medical Company was founded in 2002 and created Sensei:a vessel robotic system used in cardiac intervetion operations.It is based on master/slave configuration and surgeons sit in comfortable armchairs away from X-ray［9］.

Acrobot Sculptor is also a synergistic device.The device is a small，low-powered，special purpose robot built for use in a crowded sterile operating theatre environment.It wasclinically tested in April 1991 to perform a prostatectomy［10］.

It has a relatively smaller available manipulation field(around 30cm)making it inherently safer than an industrial robot.The robot is equipped with a milling tool，enablingbone removal according to a preoperative plan.The robot is free to move when its tip is inside a predefined safe region and gradually increases its stiffness as its tip approaches the boundary of the safe region.At the boundary，the robot becomes very stiff，thus preventing the tool from leaving the safe region.The boundaries are derived from a CT-based pre-operative plan and from the shape of the prosthetic implants.This allows the surgeon to“sculpt”bone“free-hand”.

Smaller and special purpose robots

The third geneiation ofsurgicalrobotsare smaller，lower cost and for special purpose taking the place of multifunction expensive huge robots at some degree.

Existing small robots for special purpose contain location system.The theory is similar to Kwoh＇s.But the third cohort of is close to patients，eliminating the need for patients'immobilization or motion track，which greatly simplifies the robot’s registration to the target anatomy［11］.

Moshe Shoham［11］put out a new concept:a new approach to robot-assisted spine and trauma surgery in which a miniature robot is directly mounted on the patient’s bony structure near the surgical site.To demonstrate this concept，Shoham developed a new robot(SpineAssist):a cylindricalsix-degree-offreedom parallel manipulator which operates in a semiactive mode to precisely position and orient a drill or a needle in various surgical procedures named as PSF(PosteriorSpinalFusion)，PLIF(Posterior Lumbar Interbody Fusion)，spondylolisthesis grade I and extreme scoliosis.A preliminary clinical date demonstrated that over one hundred screws in over 30 cases，72% were executed，and out of all executed procedures 98% had accurate，highly satisfactory results.

Another different small robot is“HeartLander”which was created byCarnegie Mellon University［12］.It's a mobile robotic device for minimal invasive cardiac interventions entering the pericardium through a minimal invasive incision，attaching itself to the epicardial surface，then its own power drives the little robot to reach desired location and establishes a stable platform for surgery.The problem of the beating-heart motion is thus avoided by attaching the device directly to the epicardium，and the problem of access is resolved by incorporating the capability for locomotion.The drive mechanism adheres tothe epicardium using suction which was proved to be effective in surgical stabilizers［13］.Visual feedback from the front module is relayed to an external video camera by a 1.6-mm diameter fiber optic endoscope running through the tether，and displayed to the user on the monitor.A mirror is mounted to the front module in order to angle the view of the scope toward the surface of the heart［12］.Although many technical matters need resolved，the prototype has shown up in clinical application.

Conclusion

Robotics can improve minimal invasive surgery’s accuracy，stability，efficiency and adaptability.It has been a trend to apply robotics to minimal invasive surgery.Master/slave robotic surgical system that is commercially available provides much of the needed dexterity for the realization of various endoscopic surgeries.But its high cost and huge body obstructs its wide clinical use.To fix the shortness，surgical robots in the future may be smaller，lower cost ones，such as snake-like robots for spinal minimal invasive surgeries，macrophage-like robots for elimination in vessels.And these robots are designed for some specific procedures.

It can be predicted that the third cohort of robots may do better in some procedures than master/slave robots but they can't replace master/slave ones completely.

Up till now，we haven't had any matured minimal invasive surgery robots system domestically.Andthose imported surgical robotic system are extremely expensive.So the innovation of domestic surgicalrobotic system has paramountstrategic meaningsin improving the quality ofdomestic medicare.

Surgical robotics is just at the very beginning.

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外科机器人技术在微创手术领域的发展

吴洋春，程黎明
同济大学附属同济医院脊柱外科，上海 200065

如何把机器人应用于外科手术一直是人们关注的热点问题。其中主从式机器人(例如达芬奇机器人、宙斯机器人等)已趋于完善。他们功能很强大，能完成很多手术，但是昂贵的成本和庞大的体型在一定程度上限制了他们在临床上的推广。因此用于不同手术目的的小型机器人的发展成为该领域内新的发展动向。毫无疑问的是，机器人辅助外科手术已成为微创手术的主要思路。

机器人手术;计算机辅助手术;微创手术

R 608

A

2095-378x(2013)02-0119-04

吴洋春(1988－)，男，上海人，硕士在读，脊柱微创手术相关研究。

程黎明(1968－)，男，安徽人，博士，教授主任，研究脊柱脊髓损伤修复与再生和脊柱脊髓退行性疾病。E-mail:chlm.d@163.com