Surgery – Instruments – Forceps
Reexamination Certificate
1999-10-08
2001-03-27
Buiz, Michael (Department: 3731)
Surgery
Instruments
Forceps
Reexamination Certificate
active
06206903
ABSTRACT:
BACKGROUND OF THE INVENTION
Advances in minimally invasive surgical technology could dramatically increase the number of surgeries performed in a minimally invasive manner. Minimally invasive medical techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. The average length of a hospital stay for a standard surgery may also be shortened significantly using minimally invasive surgical techniques. Thus, an increased adoption of minimally invasive techniques could save millions of hospital days, and millions of dollars annually in hospital residency costs alone. Patient recovery times, patient discomfort, surgical side effects, and time away from work may also be reduced with minimally invasive surgery.
The most common form of minimally invasive surgery may be endoscopy. Probably the most common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient's abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately ½ inch) incisions to provide entry ports for laparoscopic surgical instruments. The laparoscopic surgical instruments generally include a laparoscope (for viewing the surgical field) and working tools. The working tools are similar to those used in conventional (open) surgery, except that the working end or end. effector of each tool is separated from its handle by an extension tube. As used herein, the term “end effector” means the actual working part of the surgical instrument and can include clamps, graspers, scissors, staplers, and needle holders, for example. To perform surgical procedures, the surgeon passes these working tools or instruments through the cannula sleeves to an internal surgical site and manipulates them from outside the abdomen. The surgeon monitors the procedure by means of a monitor that displays an image of the surgical site taken from the laparoscope. Similar endoscopic techniques are employed in, e.g., arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy and the like.
There are many disadvantages relating to current minimally invasive surgical (MIS) technology. For example, existing MIS instruments deny the surgeon the flexibility of tool placement found in open surgery. Most current laparoscopic tools have rigid shafts, so that it can be difficult to approach the worksite through the small incision. Additionally, the length and construction of many endoscopic instruments reduces the surgeon's ability to feel forces exerted by tissues and organs on the end effector of the associated tool. The lack of dexterity and sensitivity of endoscopic tools is a major impediment to the expansion of minimally invasive surgery.
Minimally invasive telesurgical robotic systems are being developed to increase a surgeon's dexterity when working within an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location. In a telesurgery system, the surgeon is often provided with an image of the surgical site at a computer workstation. While viewing a three-dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the workstation. The master controls the motion of a servomechanically operated surgical instrument. During the surgical procedure, the telesurgical system can provide mechanical actuation and control of a variety of surgical instruments or tools having end effectors such as, e.g., tissue graspers, needle drivers, or the like, that perform various functions for the surgeon, e.g., holding or driving a needle, grasping a blood vessel, or dissecting tissue, or the like, in response to manipulation of the master control devices.
Some surgical tools have two working members or fingers which pivot about a common pivotal axis, such as graspers or forceps. The fingers are actuated to exert a gripping force on objects such as tissues. For a clip applier, a gripping force is used to bend a clip loaded in the clip applier and affix the clip onto tissue or the like. An actuation drive arrangement such as a pulley and cable system, a push-pull rod, or the like is provided in the surgical tool to actuate the end effectors. Because the size of the end effector is preferably kept small, existing ways of actuating the end effector may not be easily adaptable for applying the desired gripping force. For instance, in a pulley and cable system, the force transmission is often increased by increasing the size of the pulleys. In minimally invasive robotic surgery, a significant increase in the size of the pulleys used in an end effector is not desirable.
SUMMARY OF THE INVENTION
The present invention is generally directed to robotic surgery methods, devices, and systems. The invention provides an end effector having a mechanical advantage to provide enhanced end effector actuation forces without significantly increasing the size of the tool. In particular, the cross-sectional size of the end effector is kept sufficiently small so that it can be passed through a cannula sleeve to an internal surgical site and manipulated from outside the patient's body. In some embodiments, a pulley and cable mechanism is used to actuate the end effector. The coupling between the pulleys and the fingers of the end effector takes advantage of changes in moment arms for force transfer to avoid or minimize force reduction between the applied cable tensions and the resultant forces at or near the distal tips of the fingers. In specific embodiments, the coupling of the pulleys and fingers results in a force gain.
In accordance to an aspect of the present invention, an end effector arrangement of a minimally invasive surgical instrument includes a first end effector mounting formation having a proximal end portion and a distal end portion which includes a first distal pivot location. The end effector arrangement further includes a second end effector mounting formation having a proximal end portion and a distal end portion which includes a second distal pivot location. The distal end portions of the first and second end effector mounting formations are rotatably coupled together at the first and second distal pivot locations to rotate with respect to each other. Each end effector mounting formation is arranged to carry an end effector element. A first pulley is rotatable about a first center of rotation and has a first force transfer location spaced from the first center of rotation. The proximal end portion of the first end effector mounting formation is rotatably coupled with the first pulley at the first force transfer location to rotate with respect to one another. A second pulley is rotatable about a second center of rotation and has a second force transfer location spaced from the second center of rotation. The proximal end portion of the second end effector mounting formation is rotatably coupled with the second pulley at the second force transfer location to rotate with respect to one another.
In some embodiments, the first and second centers of rotation are aligned, and the first and second pulleys are rotatably coupled together at the centers of rotation to rotate with respect to one another. The first and second end effector mounting formations are rotatably coupled together to move the end effector elements toward one another to contact at a contact position and away from one another generally in a plane of movement.
In a specific embodiment, the first and second force transfer locations are generally aligned in the contact position. The centers of rotation of the first and second pulleys are disposed between the generally aligned force transfer locations and the rotatably coupled first and second distal pivot locations of the end effector mounting formati
Bui Vy Q.
Buiz Michael
Intuitive Surgical Inc.
Townsend and Townsend / and Crew LLP
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