The present invention generally relates to surgical apparatus and methods. More specifically, the invention relates to an electro-surgical instrument with inhibited surface conduction and methods for use with a robotic surgical system.
Minimally invasive surgical techniques generally reduce the amount of extraneous tissue damage during surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. One effect of minimally invasive surgery, for example, is reduced post-operative hospital recovery times. Because the average hospital stay for a standard surgery is typically significantly longer than the average stay for an analogous minimally invasive surgery, increased use of minimally invasive techniques could save millions of dollars in hospital costs each year. Patient recovery times, patient discomfort, surgical side effects, and time away from work can also be reduced by increasing the use of minimally invasive surgery.
In theory, a significant number of surgical procedures could potentially be performed by minimally invasive techniques to achieve the advantages just described. Only a small percentage of procedures currently use minimally invasive techniques, however, because certain instruments, systems and methods are not currently available in a form for providing minimally invasive surgery.
Traditional forms of minimally invasive surgery typically include endoscopy, which is visual examination of a hollow space with a viewing instrument called an endoscope. One of the more common forms of endoscopy is laparoscopy, which is visual examination and/or treatment of the abdominal cavity. In traditional laparoscopic surgery a patient's abdominal cavity is insufflated with gas, and cannula sleeves are passed through small incisions in the musculature of the patient's abdomen to provide entry ports through which laparoscopic surgical instruments can be passed in a sealed fashion. Such incisions are typically about ½ inch (about 12 mm) in length.
Laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field and working tools defining end-effectors. Typical surgical end-effectors include, for example, clamps, graspers, scissors, staplers, hooks, electrocautery devices, needle holders and the like. 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 a long extension tube, typically of about 12 inches (about 300 mm) in length, for example, so as to permit the surgeon to introduce the end-effector to the surgical site and to control movement of the end-effector relative to the surgical site from outside a patient's body.
To perform a surgical procedure, a surgeon typically passes the working tools or instruments through the cannula sleeves to the internal surgical site and manipulates the instruments from outside the abdomen by sliding them in and out through the cannula sleeves, rotating them in the cannula sleeves, levering (i.e., pivoting) the instruments against the abdominal wall and actuating the end-effectors on distal ends of the instruments from outside the abdominal cavity. The instruments normally pivot around centers defined by the incisions which extend through the muscles of the abdominal wall. The surgeon typically monitors the procedure by means of a television monitor which displays an image of the surgical site captured by the laparoscopic camera. Typically, the laparoscopic camera is also introduced through the abdominal wall so as to capture the image of the surgical site. Similar endoscopic techniques are employed in, for example, arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cistemoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like.
Although traditional minimally invasive surgical instruments and techniques like those just described have proven highly effective, newer systems may provide even further advantages. For example, traditional minimally invasive surgical instruments often deny the surgeon the flexibility of tool placement found in open surgery. Difficulty is experienced in approaching the surgical site with the instruments through the small incisions. Additionally, the added length of typical endoscopic instruments often reduces the surgeon's ability to feel forces exerted by tissues and organs on the end-effector. Furthermore, coordination of the movement of the end-effector of the instrument as viewed in the image on the television monitor with actual end-effector movement is particularly difficult, since the movement as perceived in the image normally does not correspond intuitively with the actual end-effector movement. Accordingly, lack of intuitive response to surgical instrument movement input is often experienced. Such a lack of intuitiveness, dexterity and sensitivity of endoscopic tools has been found to be an impediment in the increased use of minimally invasive surgery.
Minimally invasive robotic (or “telesurgical”) surgical systems have been developed to increase surgical dexterity and allow a surgeon to operate on a patient in an intuitive manner. Telesurgery is a general term for surgical operations using systems where the surgeon uses some form of remote control, e.g., a servomechanism, or the like, to manipulate surgical instrument movements, rather than directly holding and moving the tools by hand. In such a telesurgery system, the surgeon is typically provided with an image of the surgical site on a visual display at a location remote from the patient. The surgeon can typically perform the surgical procedure at the location remote from the patient while viewing the end-effector movement on the visual display during the surgical procedure. Typically while viewing a three-dimensional image of the surgical site on the visual display, the surgeon performs the surgical procedures on the patient by manipulating master control devices at the remote location, which master control devices control motion of the remotely controlled instruments.
Such a telesurgery system is often provided with at least two master control devices (one for each of the surgeon's hands), which are normally operatively associated with two robotic arms on each of which a surgical instrument is mounted. Operative communication between master control devices and associated robotic arm and instrument assemblies is typically achieved through a control system. The control system typically includes at least one processor which relays input commands from the master control devices to the associated robotic arm and instrument assemblies and from the arm and instrument assemblies to the associated master control devices in the case of, e.g., force feedback, or the like. One example of a robotic surgical system is the DA VINCI® system available from Intuitive Surgical, Inc. of Mountain View, Calif.
One type of end-effector which is often advantageous for use with a robotic surgical system is an electro-surgical end-effector, such as an electrocautery device. Electro-surgical devices, such as monopolar and bipolar devices, electrocautery scissors, hooks or jaws and the like, are commonly used in laparoscopic surgery and conventional surgery to cut tissue and/or coagulate small blood vessels. Thus, electro-surgical end-effectors have been developed for use with robotic surgical systems. Although many such electro-surgical end-effectors are quite effective, there are ways in which such devices may be improved.
One shortcoming of currently available end-effectors is that they are not optimally designed to inhibit conduction of current from the active electrode at the distal end of the effector back toward proximal parts of the electro-surgical instrument. Current conducted proximally from the active electrode may melt or otherwise damage one or more proximal parts of the electro-surgical instrument. Such a proximally-transmitted current may also increase the temperature of a proximal portion of the instrument and thus cause an unwanted patient burn at a location apart from the active electrode.
Another possible shortcoming of currently available devices is that the end-effector is typically permanently connected to the rest of the electro-surgical instrument. Although such permanently connected end-effectors work well, the permanent connection makes cleaning of the electrode difficult, often requiring the entire electro-surgical instrument to be autoclaved or otherwise cleaned. Such permanently attached electrodes may also sustain larger amounts of wear and tear before being replaced, which may compromise performance of the end-effector.
Therefore, a need exists for improved electro-surgical instruments and end-effectors for use with a robotic surgical system. Improved end-effectors would include means for inhibiting surface conduction of current from a distal active electrode to more proximal portions of the end-effector and to the electro-surgical instrument. Ideally such end-effectors would be available either permanently attached to an electro-surgical instrument or removably attachable to an instrument. At least some of these objectives will be met by the present invention.