Abstract:
A surgical instrument is configured to aid in performing a procedure of detaching an internal mammary artery (IMA) and the like, from the connecting tissues and side branch vessels which surround the artery in its native location, wherein the detaching procedure is preliminary to the performing of a coronary artery bypass grafting procedure and wherein the IMA is detached via a minimally invasive thoracotomy. To this end, an elongated slender rod includes a handle at its proximal end and an artery engaging loop, arc, fork configuration, or hook at its distal working end. Embodiments may incorporate electrosurgical capability or electrical insulation. A surgeon thus has means for harvesting an intact and undamaged graft vessel from its native location through a minimally invasive incision with enhanced speed, visibility, and freedom of motion.

Description:
RELATED APPLICATIONS 
     This application is a divisional application entitled to priority from application Ser. No. 09/106,867, filed on Jun. 29, 1998, now U.S. Pat. No. 6,110,170, which is a continuation-in-part of co-pending application Ser. No. 08/835,675, filed on Apr. 10, 1997, which is a continuation-in-part of co-pending application Ser. No. 08/619,046, filed on Mar. 20, 1996, the disclosures of which are incorporated herein by reference as if set forth in full. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to minimally invasive surgical instruments and procedures and, in particular, to surgical tools for dissecting, manipulating and harvesting an artery, such as the internal mammary artery (IMA), from its natural location in connection with a coronary artery bypass grafting (CABG) procedure. 
     BACKGROUND OF THE INVENTION 
     Surgeons are constantly striving to develop advanced surgical techniques resulting in the need for advanced surgical devices and instruments required to perform such techniques. Recent advances in the surgical field are increasingly related to surgical procedures which are less invasive and reduce the overall trauma to the patient. To illustrate, in a conventional CABG procedure it has been common practice for surgeons to perform a sternotomy to expose the body cavity in the thoracic region. To this end, a surgeon makes a long incision down the middle of a patient&#39;s chest, saws through the length of the sternum and spreads the two halves of the sternum apart. Retractors then are employed to provide access to the vessels where an anastomosis will be performed. The CABG procedure is further complicated by the need to stop the beating of the heart by means of cardioplegia and to attach the patient to a cardiopulmonary bypass (CPB) machine to continue the circulation of oxygenated blood to the rest of the body while the graft is sewn in place. 
     To create a pedicled bypass graft, the surgeon dissects a sufficient length of the artery from its connective tissue, then transects the artery, and connects the transected end to a diseased target coronary artery distal to an obstruction, while leaving the other end of the dissected artery attached to the arterial supply, thus restoring blood perfusion to the heart. 
     The internal mammary arteries (IMAs), left (LIMA) and right (RIMA), are particularly desirable for use as pedicled bypass grafts as they are conveniently located, have diameters and blood flow volumes that are comparable to those of coronary arteries, and in practice typically have patency rates superior to other grafts such as saphenous veins from the patient&#39;s leg. Extending from the subclavian arteries near the neck to the diaphragm and running along the backside of the ribs adjacent the sternum, the IMAs deliver blood to the musculature of the chest wall. The LIMA is typically used as an arterial source for target locations on the left anterior descending coronary artery (LAD), the diagonal coronary artery (Dx), the circumflex artery (Cx), the obtuse marginal artery, and the ramus intermedius coronary artery. The RIMA is typically used for connection to all of the same target locations, as well as the right coronary artery (RCA) and the posterior descending artery. 
     Use of either IMA as a bypass graft first involves harvesting the IMA free from the inside chest wall. In conventional CABG approaches, access to the IMA is obtained through a sternotomy or major thoracotomy incision (involving sawing through one or more ribs) through the chest. Harvesting of the IMAs is accomplished with relative ease due to the working space made available by the stemotomy or major thoracotomy. 
     An IMA is detached from its connective tissue until there is sufficient slack in the IMA to allow the distal end thereof to be attached to the target vessel such as the left anterior descending coronary artery (LAD). The sternotomy incision provides the surgeon with ready access to the IMA since it is exposed by the spreading of the sternum. The IMA thus may be transected at its distal end and detached from the connective tissues in its native location in the sternum region, while still attached at its proximal end to its arterial supply, using the usual surgical instruments such as electrosurgical pencils, scissors, forceps, etc. 
     The CABG procedure would be improved if surgeons could avoid the need for arresting the heart, thereby eliminating the need to connect the patient to a cardiopulmonary bypass machine to sustain the patient&#39;s life. To this end, recent developments lend themselves to CABG procedures using surgical techniques which enable surgeons to perform the procedure while the heart is beating. This eliminates the need for the lengthy and traumatic cardiopulmonary bypass procedure, cardioplegia is unnecessary, the overall surgery is much less invasive and traumatic, and patient recovery time and costs are reduced. Recently, progress has been made in advancing minimally invasive surgical techniques, particularly in cardiothoracic surgery, which eliminates the need for a stemotomy or major thoracotomy. Access to the heart with these minimally invasive techniques is obtained through one very small surgical incision (such as a minimal thoracotomy) or through several percutaneous cannulas known as trocars positioned intercostally in the thoracic cavity of the patient Visualization of the operative area may be facilitated by thoracoscopes which typically consist of a video camera configured for introduction through a small incision or trocar to allow observation of the target area on a video monitor. 
     With the advent of these minimally invasive techniques, harvesting the IMA has become more complex and difficult due to a restricted work space and access, and to reduced visualization of the IMA. The procedure of detaching the IMA likewise must be performed through the minimal thoracotomy. Surgeons presently perform the procedure of detaching the IMA from its native location with the aid of the usual instruments such as the electrosurgical pencils, scissors and forceps of previous mention. These instruments are not specially designed for use in less invasive procedures and do not facilitate the desired gentle handling of the IMA as it is detached from the surrounding connective tissues to provide the bypass graft for the CABG procedure. The harvesting procedure itself may actually be lengthened and the trauma to the vessel potentially increased by the less invasive techniques, in part because a number of tools must be introduced and exchanged through the restricted incision(s). This is a concern as a high degree of precision is required when harvesting a bypass vessel to avoid injury (such as over cutting or cauterizing) to the vessel which may in turn lead to increased rates of occlusion in the vessel in the months and years after the procedure. 
     Although low-profile micro-surgical instruments are readily available for some procedures, such has not been the case for harvesting the IMA and other similarly situated arteries in minimally invasive CABG procedures. Surgical instruments designed for laparoscopic and other minimally invasive applications are not generally suitable for performing minimally invasive CABG. Most laparoscopic procedures, for example, target body structures which are quite large in comparison to coronary vessels, and do not require the high degree of precision required in a CABG procedure. Accordingly, laparoscopic instruments generally provide only limited angular orientation, making them unsuitable for harvesting of the IMA and other similarly situated arteries through a minimal thoracotomy or an intercostal puncture site. 
     Typically, an electrosurgical tool (often called a “Bovie”) similar to that described in U.S. Pat. No. 5,013,312 is used to free a length of the IMA by incising the endothoracic fascia and severing the side branch vessels to free the IMA. The use of such electrosurgical devices is well known in the art and can be crucial in controlling bleeding during harvesting of the IMA. Such devices are typically in the form of scalpels, forceps, and scissors, and employ at least one conductive electrode connected thereto. For example, a bipolar electrosurgical instrument comprising a fork-shaped configuration is described in U.S. Pat. No. 4,671,274. This instrument combines the functions of tissue manipulation and electrocautery, and finds application for control of bleeding during the transection of blood vessels; however, it involves separate hinged jaws and cannot provide an adequate range of angular motion through a minimally invasive thoracotomy. 
     Despite the use of an electrosurgical tool, because initial cauterization may be applied over too short a length of a vessel or side branch to be complete, it is common practice to apply ligatures or surgical clips to control bleeding before complete coagulation is effected. Applying ligatures or clips can be time-consuming. In addition, if clips are accidentally loosened and dropped inside the patient&#39;s body cavity, there can be serious complications and additional expenditure of time in the procedure. 
     When an electrosurgical tool is used in simultaneous conjunction with other instruments that are not electrically insulated, there is a serious risk of accidental electric short-circuiting or arcing due to contact or close proximity. This can lead to traumatic electric shock to the patient or the surgeon, damage to an instrument, disruption of the procedure, or over or under cutting or cauterization, which can adversely affect the control of bleeding or the integrity and patency of the graft vessel. 
     Accordingly, it would be highly desirable when performing a detachment, or “takedown” procedure on the IMA, to provide a specialized instrument which allows the surgeon a greater range of visibility and angular motion to harvest an intact and undamaged length of vessel more rapidly and gently with fewer instruments obstructing the operating field and with minimal risk of accidental electric shock, while the tissues and side branch vessels are being dissected with the aid of a surgical knife or scissors. It would further be desirable to reduce or eliminate the need for surgical clips or sutures in the IMA harvest procedure. 
     SUMMARY OF THE INVENTION 
     The present invention provides a specialized surgical instrument which overcomes the deficiencies of previous mention, that is, provides gentle handling of the IMA when performing the procedure of detaching the IMA from its native location during the less invasive CABG procedure using the comparatively small incision or thoracotomy in the chest. It potentially reduces the number of instruments obstructing the field and, in some embodiments, provides malleable instrument shafts, thereby allowing the surgeon a greater range of visibility and angular motion to harvest an intact and undamaged length of vessel more rapidly. It provides electrically insulated instruments and self-contained electrosurgical instruments that reduce the risk of accidental electric shock. It provides embodiments that potentially reduce the need for surgical clips or sutures to control bleeding. These advantages are also applicable to the dissection or harvesting of other vessels for use as a graft in a vascular surgical procedure. 
     More particularly, in selected embodiments the invention comprises an elongated slender rod, permanently attached to a handle of greater cross section configured for comfortable grasping by a surgeon. The slender rod may be formed of a material such as a firm plastic, but preferably is formed of stainless steel. The distal end of the rod is formed into a loop or coil, an arcuate segment or other preselected curved configuration which provides means for capturing the IMA, or other vessel, which is being detached, dissected or otherwise handled. Some of the various embodiments contemplated by the invention include a full  360  degree loop configuration with the overlapped coil of the loop axially spaced apart, as well as partial loop and arcuate configurations. The distal, or working, end of the invention is configured and is of selected dimensions to allow a surgeon to capture a vessel at a distant location through small openings in a patient&#39;s body, and to then gently manipulate the vessel as necessary in the specific surgical procedure. Thus, the invention provides the advantage of remotely handling a vessel with a minimum of trauma during minimally invasive surgical procedures. 
     In alternative embodiments, the invention includes an elongated tube coaxially attached to the handle, and a rod actuating means integral with the handle. In response to the rod actuating means, the rod and the integral working end is extended from the distal end of the tube as when in use, or may be retracted into the tube when not in use. 
     In further alternative embodiments, the invention includes a fork configuration that can engage and manipulate a vessel and connective tissue. These embodiments facilitate safe and rapid severing of the many side branches that must be separated from the main vessel, with minimal bleeding or damage to the harvested vessel. Described configurations protect the harvested vessel from accidental damage by an electrosurgical knife. Instruments according to the invention are coated with electrically insulating material to prevent accidental shortcircuiting and arcing when used with electrosurgical tools. Other embodiments incorporate selfcontained unipolar or bipolar electrosurgical capabilities, thereby eliminating the need for extra instruments, potentially reducing or eliminating the need for surgical clips or sutures to control bleeding, and improving the accuracy, speed, and safety of vascular graft dissection. 
     In still other alternative embodiments, the invention includes an electrically energized cautery wire, coil, ribbon, etc., selectively embedded or otherwise contained in a loop, hook, or other curved configuration used to capture the vessel. The cautery element incorporated in the curved configuration provides an electrosurgical instrument that not only can engage and gently manipulate a vessel, or other elongated bodily structures and connective tissue, but which also can be used to rapidly sever and cauterize side branches of the vessel and separate the vessel and the tissue around it from their native bed. This is turn eliminates the need for extra instruments and for surgical clips or sutures. The cautery means may be unipolar or bipolar and the embodiments may include selected fiberoptic light and/or smoke evacuation means in the region of the curved configuration to enhance visualization of the vessel. The body of the curved configuration, that is, the insulated cross-section thereof, acts as a spreading means, applying tension to the tissue to be divided by the cauterizing member, i.e. cautery element, and insulates the nearby tissue, and most importantly the vessel itself, or other elongated bodily structure or tissue, from the electrosurgical action and heat of the cautery element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 and 2 are top and elevational views, respectively, of an embodiment of the present invention. 
     FIG. 3 is a perspective view illustrating a use of the invention in cooperation with surgical scissors when performing the procedure of detaching the IMA from its native location. 
     FIGS. 4 and 5 are elevational views of alternative embodiments of the invention. 
     FIGS. 6 and 7 are elevational views of a further alternative embodiment of the invention embodying a retractable distal working end. 
     FIG. 8 is a partial top view of the embodiment of FIGS. 6,  7 . 
     FIG. 9 is a cross-sectional view taken along section line  9 — 9  of FIG.  7 . 
     FIG. 10 shows an embodiment combining a loop with a fork configuration. 
     FIGS. 11A-11C illustrate fork configurations having fingers of unequal lengths. 
     FIG. 12 is a perspective view showing a use of the invention including a fork configuration to assist in detaching the IMA. 
     FIG. 13 is a perspective view illustrating the use of the invention including a fork configuration combined with a loop to assist in detaching the IMA. 
     FIG. 14 shows an embodiment of the invention comprising a fork having an articulating finger and equipped with electrosurgical capability. 
     FIGS. 15A and 15B are elevational and end views respectively, illustrating a further embodiment including a curved or hooked configuration containing exposed cautery wire means as an electrode for severing and cauterizing side branches and connective tissue. 
     FIGS. 16A and 16B are top views of alternative curved or hooked configurations of FIGS. 15A,  15 B. 
     FIGS. 17A and 17B are elevational and end views respectively of the exposed cautery wire means of FIGS. 15A,  15 B. 
     FIGS. 18A and 18B are perspective and top views respectively of an alternative curved or hooked configuration having exposed cautery wire means electrodes. 
     FIGS. 19A and 19B are a perspective and side view, respectively, illustrating a specialized surgical instrument of the invention including an electric cautery curved configuration and smoke evacuation means. 
     FIG. 20 is an elevational view of the distal working end of the cautery curved configuration instrument of FIGS. 19A,  19 B, further depicting light means. 
     FIG. 21 is a perspective view of a cross section and portion of a curved configuration illustrating means for securing an exposed cautery wire within a selected surface of the curved configuration. 
     FIG. 22A is an elevational view illustrating an alternative means for securing or confining an exposed cautery wire to a curved configuration. 
     FIGS. 22B and 22C are cross-sectional views taken along section lines A—A and B—B respectively of FIG.  22 A. 
     FIG. 22D is a cross-sectional view of the invention of FIG. 22A illustrating an alternative cautery electrode confining means of the invention. 
     FIG. 23 is an elevational view illustrating an alternative exposed cautery wire means using a twisted wire electrode configuration. 
     FIG. 24A is a cross-sectional view of the curved configuration and cautery electrode configuration of FIG. 23, but using an alternative means for containing the electrode within the surface of the curved configuration. 
     FIG. 24B is a cross-sectional view of an alternative embodiment of a cautery electrode/curved configuration combination. 
     FIG. 25 is a cross-sectional view of a portion of a cautery electrode, illustrating a bipolar electrode configuration. 
     FIGS. 26A through 26E are perspective views of portions of respective curved configurations illustrating several alternative embodiments of electric cautery curved configurations using a coil electrode. 
     FIGS. 27A and 27B are perspective views illustrating an alternative embodiment of the invention including a retractable curved configuration formed of a material having an inherent shape-memory property. 
     FIG. 28 is an elevational view illustrating an alternative retractable curved configuration of the FIGS. 27A,  27 B. 
     FIGS. 29A,  29 B are side views illustrating another alternative pre-formed curved configuration of the invention. 
     FIG. 30 is a bottom view illustrating a modification of the curved configuration of FIGS. 29A,  29 B. 
     FIG. 31 is a side view of an alternative embodiment of an electrosurgical instrument embodying the curved configuration of FIGS. 29A,  29 B, and  30 . 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     FIGS. 1 and 2 illustrate one embodiment  12  of a surgical instrument in accordance with the present invention, which includes a handle  14  at the proximal end securely attached to, or formed as part of, an elongated slender rod  16 . Rod  16  may have a circular, oval, rectangular, triangular or other cross-sectional shape over all or any portion of its length, and may be solid or hollow in whole or in part, containing one or a plurality of internal cavities. The distal end of the instrument, and particularly of rod  16 , is formed into a loop  18 . The loop  18  may be continued to form a complete circle as depicted in FIGS. 1 and 2, or may be of less than a full circle, such as exemplified by the arcuate embodiments depicted in FIGS. 4 and 5 below. Loop  18  has an inside diameter of the order of one-half to three-quarter inch, and the overlapping tip  19  of the loop is spaced from the body of the loop a distance, a, of the order of one-fourth to one-third inch. Preferably, the circumference of loop  18  does not lie in a single plane but is displaced helically to provide axial displacement between separate points on the loop. As depicted in the figures by way of example only, loop  18  is bent at an angle relative to rod  16  of approximately 10 degrees in the top view (FIG.  1 ), and at an angle of approximately  20  degrees in the elevational view (FIG.  2 ). Rod  16  and handle  14  may be formed in whole or in part of stainless steel, aluminum, or plastic, respectively. If a combination of materials is used, the rod is bonded or glued to the handle via a suitable axial bore in the handle. It may be preferable for use in electrosurgical procedures that the instrument be non-conductive electrically; accordingly, if rod  16  (and/or handle  14 ) is formed of stainless steel or other electrically conductive material, it may be coated with a non-conductive biocompatible material such as PTFE or polyamide polymer. Rod  16  and handle  14  also may be made of any of the other conventional biocompatible medical plastics having sufficient tensile and bending strength. 
     In a preferred embodiment, rod  16  is formed of a stainless steel material and thus is relatively resistant to force applied transversely to the rod length. However, a partial length  20  (FIG. 1) of rod  16  may be annealed to have a malleable property, whereby rod  16  can be deformed by the surgeon to tailor the precise curvature thereof depending on the nature of the procedure, the patient&#39;s anatomy, and the preferences of the surgeon. Loop  18  can likewise be annealed in whole or in part to have a malleable property. 
     FIG. 3 illustrates a manner of use of the invention employing the embodiment  12  of FIGS. 1 and 2. It is to be understood that any of the embodiments presented herein also may be used in similar fashion to perform the same function. To this end, surgical scissors  22  may be introduced by a surgeon through a thoracotomy  24  and used to initiate the severing of tissues from a vessel such as an IMA  26  to thus initiate detachment of a first segment of the IMA. In the following description, the IMA is used as the example, with the understanding that other vessels may be harvested using the devices and procedures of the invention. Upon slight detachment of the IMA, instrument  12  of the invention also is inserted through the thoracotomy  24  and the tip  19  of loop  18  is introduced past IMA  26 . A slight twist of instrument  12  causes loop  18  to encircle the IMA whereupon the surgeon has complete control of the direction in which force may be applied to urge the IMA gently from its native location. Scissors  22  simultaneously are used to dissect tissues and side branch vessels  25  from the IMA. The surgeon may continue the procedure of dissecting the connecting tissues and side branch vessels while pulling the IMA away from the endothoracic fascia with instrument  12  as depicted by arrow  27 , until a sufficient length of the IMA has been detached from the endothoracic fascia to allow performing a CABG procedure. The invention thus allows capturing the IMA and provides the surgeon thereafter with complete control of the artery to allow it to be manipulated gently in any direction during the detaching process. 
     FIG. 4 illustrates an alternative embodiment  28  of the invention, wherein the full loop  18  of the FIGS. 1 and 2 is defined by one or more arcuate segments, which comprise at least one arc  30  formed in the distal end of rod  16 . Arc  30  terminates in a tip  32  which is bent away from the arc configuration to extend generally coaxially with rod  16 . Tip  32  guides the introduction of arc  30  through the surrounding tissues and past the IMA, whereby arc  30  is used to manipulate the IMA while detaching it from the endothoracic fascia. 
     FIG. 5 illustrates a further alternative embodiment  34  of the invention, wherein the loop  18  of FIGS. 1 and 2 is defined by a slightly ovaled partial loop  36  of approximately three-fourths of a full oval or circle. This configuration provides a tip  38  which allows manipulating the IMA in various directions without completely encircling the artery as with loop  18 . As depicted in FIG. 5, rod  16  may be annealed along a length  20  as described in FIG. 1, to allow readily deforming the rod to tailor the contour of the instrument to meet the requirements of the procedure, the anatomy of the patient, and the preferences of the surgeon to facilitate the capture and manipulation of the IMA by loop  18 , arc  30  or partial loop  36 . 
     FIGS. 6-9 depict portions of alternative embodiments  40  of the invention employing a retractable distal working end of the instrument. Rod  16  and loop  18  (or arc  30  or partial loop  36 ) may be retracted into a protective housing when not in use, and extended to provide loop  18  when the instrument is to be used. Instrument  40  includes a hollow handle  42  having thus a lumen  44 . An elongated tube  46  is coaxially formed with the handle  42  and includes a lumen  48  extending the length of the tube  46  in communication with lumen  44 . A slender elongated rod  50  similar to rod  16  of FIGS. 1,  2 ,  4 , and  5  is dimensioned to fit in slidable relation within lumen  48  of tube  46 . Rod  50  is formed, for example, of a nickel-titanium alloy material having an inherent shape-memory property. In this embodiment the distal working end of rod  50  is formed into a loop  52  similar to the loop  18  of FIGS. 1 and 2, which thus is the shape to which the shape-memory material, that is, the distal working end of rod  50 , will return. It is to be understood that the distal working end of rod  50  could be formed into the arcuate or partial loop configurations of FIGS. 4 or  5 , respectively, rather than the full loop configuration  18 ,  52 . FIG. 6 depicts instrument  40  with rod  50  extended to provide an exposed vessel capturing distal working end for use by a surgeon. 
     FIG. 7 depicts the instrument  40  with rod  50  retracted into tube  46 . As may be seen, the shape-memory material is sufficiently flexible that, when rod  50  is drawn into lumen  48  of tube  46 , loop  52  is forcibly deformed to assume the shape of the lumen, that is, loop  52  is straightened. Thus, the working end of the instrument may be fully retracted into the protective housing of tube  46 . When the instrument is to be used in a procedure of detaching a vessel such as the IMA from its connecting tissues, rod  50  is extended from tube  46 , whereupon due to the inherent shape-memory property of the nickel-titanium alloy material, loop  52  will automatically re-form into its memorized shape depicted in FIG.  6 . 
     Various mechanical devices may be employed with handle  42  to provide rod  50  with working end  18 ,  30 ,  36  operated by an actuating means  54 . By way of example only, actuating means  54  herein includes a reciprocatable slide  56  formed with a cylindrical member  58  slidably fitted within lumen  44  of handle  42 . Cylindrical member  58  is integrally formed with a radially-extending flat yoke  60  which, in turn, has a thumb-engaging member  62  secured thereto. Flat yoke  60  reciprocates within a slot  64  formed in the side wall of handle  42  in communication with lumen  44 , and thumb-engaging member  62  is positioned exterior of slot  64  and outer cylindrical surface of handle  42  for access by the surgeon&#39;s thumb or fingers. Rod  50  is coaxially secured to cylindrical member  58  and thus any reciprocation of thumb-engaging member  62  imparts similar reciprocation to rod  50 . 
     Although slidable actuating means  54  is illustrated herein, other mechanisms may be used. For example, the proximal end of rod  50  may be provided with external helical threads, wherein a coaxial circular dial with internal matching helical threads is disposed within the distal portion of handle  42  with the internal threads engaging the external threads. Selective rotation of the dial thus reciprocally translates rod  50  to extend or retract the rod and working end of instrument  40 . 
     An alternative preferred embodiment of the invention comprising a fork configuration at the distal working end of rod  16  is illustrated in FIGS. 10,  11 A- 11 C,  12 ,  13 , and  14 . The fork configuration may be combined with loop  18  as depicted in FIGS. 10 and 13 or with arcuate configuration  30  or partial loop configuration  36  shown in FIGS. 4 and 5 respectively; alternatively a fork configuration may be used in place of loop  18  or equivalents at the distal working end of rod  16 . It is to be understood that a fork configuration may be combined with malleable rod section  20 , handle  14 , retractable rod  50 , hollow handle  42 , actuating means  54 , or any other element described herein. 
     Proceeding, FIG. 10 illustrates an embodiment  100  in which fork configuration  102  and loop  18  are combined at the distal working end of rod  16 . Fork configuration  102  comprises a plurality of fingers  104  projecting from the distal end of the fork configuration. For purposes of illustration a finger  104  is formed into a arcuate or circular configuration, such as loop  18 , terminating in tip  19 . The diameter of the loop portion  18  of finger  104  may be slightly tapered from its proximal connection point to tip  19 . Preferably, loop  18  is between about 270? and 360?. Tip  19  and the tips of fingers  104  preferably end in a bulbous configuration or have a tear drop shape. Fork  102  may comprise at least two and up to any greater number of fingers  104 , one or more of which may be formed into a loop or equivalent, depending on the detailed design of embodiment  100 . Likewise the lengths, widths, and spacing of fingers  104  may be chosen to be equal or unequal in any order at the discretion of the instrument designer. Fingers  104  may be straight, bent, curved, or adjustably shaped at the discretion of the designer. 
     FIGS. 11A-11C illustrate fork configurations at the distal working end of rods  16  having fingers of unequal lengths. FIG. 11A shows a fork  110  having inner finger  114  shorter than outer fingers  112  and  116 . FIG. 11B shows a fork  120  in which left-hand outer finger  112  is shortest, inner finger  114  is intermediate in length, and right-hand outer finger  116  is longest. FIG. 11C shows a fork  130  having inner finger  114  longer than outer fingers  112  and  116 . Preferably, any two adjacent fingers define a rounded “V”-shape groove to accommodate vessels of varying diameters for scraping or dissecting tissue away from a vessel. 
     FIG. 12 illustrates a manner of use of the invention employing an embodiment  140  comprising a fork configuration  142 . In the illustrated embodiment a fork  142  is connected to the distal working end of rod  16 , which is fastened to handle  14 . Fork  142  comprises fingers  144 , which terminate at their distal ends in enlarged hemispherical or rounded tips  146 . Tips  146  are configured to make gentle atraumatic contact with a patient&#39;s tissue. In the illustrated procedure fork  142  gently captures, retracts, and stabilizes IMA segment  26  or other tubular organ away from its connective tissue. The IMA and/or separated and clipped side branch and tissue  25  may be captured and woven between fingers  144  to provide additional control and stability. Combination of a malleable rod  20  (FIG. 1) and adjustable finger shapes provide the surgeon with a wide range of angular motion through a small minimally invasive incision. An electrosurgical knife  148 , such as a “Bovie” or such as that described in U.S. Pat. No. 5,013,312, may then be employed by the surgeon to coagulate and cut offside branch  25  from IMA  26 . Fingers  144  provide a sliding guide surface for knife  148  to cut offside branch  25  cleanly and accurately, and protect IMA  26  from accidental injury by the knife. Instrument  140  positions, stabilizes, and protects IMA  26  during the described dissection procedure, reducing the time and risk of the procedure. 
     FIG. 13 illustrates a manner of use of the invention employing an embodiment  150  comprising a fork configuration  152  combined with loop  18  at the distal working end of rod  16  affixed to handle  14 . In the illustrated procedure loop  18  captures and gently stabilizes IMA  26 . Fingers  154  of fork  152  are curved to engage and retract IMA  26  and to separate side branch  25  between fingers  154 . The surface defined by adjacent fingers  154  protects IMA  26  and provides a sliding support to guide electrosurgical knife  148  to coagulate and cut offside branch  25  quickly, accurately, and safely, reducing the time and risk of the procedure. Embodiment  150  illustrates the cooperative action between fork  152  and loop  18 , wherein the loop controls IMA  26 , while the fork captures side branch  25  and guides knife  148 . This functionality potentially reduces the need for extra instruments in the small operating field. 
     FIG. 14 depicts an embodiment  160  of the invention comprising a fork  162  having an articulating finger  166 . In the illustration of FIG. 14 inner finger  166  is pivotally connected to fork  162  by means of pivot bearing  168  and toggles either right or left to engage an outer stationary finger  164 . Alternatively outer fingers may pivot to engage an inner finger. For purposes of illustration only, articulating finger  166  may be actuated by cable mechanism  170 . Pulling on the right-hand cable as illustrated by the arrows  171  pivots articulating finger  166  to the right, and pulling on the left-hand cable pivots articulating finger  166  to the left. Other actuating mechanisms, such as push rods, may alternatively be employed. Fingers  164  and  166  may include cutting blade edges, clamping jaws, or grasping surfaces. Embodiment  160  may comprise only mechanical elements, or may provide for unipolar or bipolar electrosurgery by means of electrical leads  172  connected to a suitable energy source. For example articulating finger  166  may be electrically insulated from stationary fingers  164  and connected to a unipolar electrical energy source by means of electrical leads  172 , or articulating finger  166  may be electrically insulated from stationary fingers  164  with fingers  166  and  164  connected respectively to opposite poles of a bipolar electrical energy source by means of electrical leads  172 . Those skilled in the art will recognize that alternative electrode arrangements may be used with the present invention. 
     Embodiment  160  can function as an electrosurgical fork  162  with all mechanically stationary fingers  164 . One or more fingers  164  may be configured with cutting edges and connected to unipolar or bipolar energy sources. In this configuration the electrically active fingers may serve as electrosurgical cutting or coagulating (“Bovie”) knives. In a configuration comprising one or more articulating fingers  166 , embodiment  160  can function as electrosurgical scissors, wherein the knife edge of one finger engages another finger. 
     In operation embodiment  160  may be used to capture, engage, manipulate, clamp, coagulate, and cut vessels such as the IMA and side branches, tubular body organs, and related tissue. Use of embodiment  160  to coagulate and cut potentially eliminates the need for a separate electrosurgical knife, thereby reducing the number of instruments in the minimal operating field and thus increasing visibility and freedom of motion therein. When used alone or in combination with electrically insulated instruments embodiment  160  reduces the risk of accidental electrical shock or unwanted electrosurgical effects. Use of embodiment  160  further potentially reduces the need to apply mechanical surgical clips to side branches, thereby reducing the time for a procedure involving application and removal of mechanical clips, and reducing the risk of misplaced or lost mechanical surgical clips within the patient? body. A vessel or side branch can be woven and captured through the spaces between fingers  164  and  166 , thereby exposing a greater length of vessel or side branch to coagulating energy, and insuring complete cauterization prior to cutting. 
     In a manner equivalent to that of the embodiment  160  of FIG. 14, various alternative embodiments of an electric cautery member having a hooked or curved configuration are illustrated in FIGS. 15 through 31, and provide a specialized electrosurgical instrument in accordance with the invention for capturing, manipulating, cauterizing, and severing vessels, other elongated bodily structures and connective tissue. To this end, FIGS. 15A and 15B illustrate a basic embodiment of an electrically energized cautery loop instrument, including handle  14  and rod  16  secured at its proximal end to the distal end of the handle. The distal end of the rod  16  is formed in a hook or curved configuration  18  of selected configuration for engaging, manipulating and harvesting vessel  26 . The curved configuration  18  includes a groove formed within the top and leading surfaces along a major portion thereof for confining therein a cautery electrode in the form of a wire  200 . The rod  16  includes a lumen therein (not shown) through which an electrical conductor supplies electrical current to the cautery wire  200  from a suitable energy source (such as the source depicted in FIG. 14) via an electrical cord  202  and an on/off switch  204  in the handle  14 . As illustrated by a line  205 , the handle  14  and rod  16  are configured so that the handle is in-line with the working area of the curved configuration  18 , that is, the upper surface of the curve containing the wire  200 . 
     The FIGS. 16A and 16B illustrate alternative curved configurations  18  for the cautery curved configuration electrosurgical instrument of FIGS. 15A,  15 B. FIG. 16A shows the curved configuration  18  formed at a 30 to 40 degree angle to the rod  16 . FIG. 16B shows the curved configuration  18  at generally right angle to the rod  16 . The curved configuration  18  in FIGS. 15A,  15 B has no angle but is generally formed in-line with the rod  16 . Thus, the invention intends that the curved configuration  18  can be formed at various angles and arc lengths, i.e. an arc of selected length. 
     FIGS. 17A and 17B illustrate in further detail a modification of the cautery curved configuration of FIGS. 15A,  15 B, and includes handle  14  formed, for example, of a stainless steel tube  206  suitably insulated by means of a plastic shrink tube  208  disposed about the tube  206 . Only a portion of the handle  14  is shown. A curved configuration  18  formed of a suitable high temperature insulating material is secured along a straight portion  210  within the distal end of the tube  206 , with the curved configuration  18  thereof extending from the handle. In accordance with the invention, a cautery electrode in the form of a wire  212  extends through the tube  206  and a lumen in the straight portion  210  of the curved configuration. The cautery wire  212  then is confined in a groove  214  (FIG. 17B) in the top and leading surfaces of the curved configuration  18 . The distal end of the cautery wire is secured within the tip  19  of the curved configuration  18  as depicted at  216 . A nonconductive disk  218  secured within the tube  206  and to the cautery wire  212  provides a shoulder for one end of a spring  220 , the other end of which is confined by the end of the straight portion  210 . The force of the spring  220  against the disk  218  imparts tension to the cautery wire  212  to maintain it in place in the groove  214  during a harvesting procedure. As depicted in FIGS. 15 and 17, the cautery curved configuration instrument is connected to a unipolar energy source. 
     The cautery electrode of FIGS. 17A,  17 B, as well as any of the electrodes of further description hereinafter, may be formed of various electrically conductive materials such as, for example, stainless steel, nickel chromium alloy, nickel titanium alloy, titanium, etc. 
     FIGS. 18A and 18B illustrate a configuration of the present invention wherein the curved configuration  18  is formed at a selected angle to the rod  16 , such as previously illustrated in FIG.  16 A. In FIGS. 18A,  18 B the curved configuration  18  is provided with a pair of cautery electrodes in the form of wires  224  and  226  embedded in opposite side surfaces of the curved configuration. The wires  224 ,  226  could be replaced with cautery ribbons. As in FIGS. 15-17, the cautery wires  224 ,  226  are exposed along the major portion of the curved configuration to provide electrical contact with connecting tissue and side branches as the instrument is advanced or retrieved along the vessel being harvested. The curved configuration of FIGS. 18A,  18 B is particularly useful in harvesting vessels which extend parallel to the center line of the handle and rod of the instrument, as when harvesting the LIMA through a xyphoid or sub-xyphoid incision. 
     FIGS. 19A,  19 B illustrate an alternative embodiment of an electrosurgical instrument of the invention, generally similar to those of FIGS. 15 and 17. FIG. 19A illustrates the embodiment in use harvesting a vessel  26  such as the LIMA or other elongated bodily structure or tissue. The embodiment in FIGS. 19A,  19 B includes handle  14  which extends distally to the working area of the cautery curved configuration  18 . As illustrated, a surgeon gently manipulates the vessel  26  to disengage it from surrounding tissue. In particular, the body of the curved configuration  18  acts as a spreading means which applies tension to the tissue being divided and which insulates nearby tissue and in particular the vessel  26  itself from the electrosurgical action and the heat of the cauterizing element. It this example, the vessel is also grasped with a pair of forceps  230  while the cautery hook instrument spreads, tensions and manipulates the vessel  26  when urged as depicted by arrow  231 , to sever and cauterize side branches  25  and connective tissue using an exposed cautery electrode (depicted here as a wire)  232  contained in the side surface of the curved configuration  18 . The process of cauterizing and cutting of tissue and side branches generates substantial smoke  233  which impairs visualization of the working area. Thus, the embodiment of FIGS. 19A,  19 B also includes a suction lumen  234  which extends within the handle  14  to terminate in a suction port  236  in the working-area, thereby defining a smoke evacuation means integral with the instrument. To further facilitate visualization of the working area, the embodiment also may include a fiberoptic light  238  (FIG. 20) within the handle  14  with the light lens disposed to illuminate the working area The light is supplied via a suitable fiberoptic light guide (not shown) also housed in the handle  14 . Electrical current is provided to the cautery wire  232  from a suitable energy source via a pair of button switches  237 ,  239  embedded in the handle  14  and an electrical cord  240  (FIG.  19 B). The button switches supply suitable electrical energy for separately selecting the process of coagulation or severing of side branches and tissue. Button switches  237 ,  239  and cord  240  replace the switch  204  and cord  202  previously depicted in FIG.  15 A. 
     FIG. 20 illustrates the working end of the instrument similar to that in FIGS. 19A,  19 B, including a distal portion of the handle  14  and a curved configuration  18  having the cautery electrode or wire  232  suitably embedded or otherwise attached to the side surface of the curved configuration. Suction is provided via the suction or smoke evacuation port  236 , and light is provided via the fiberoptic light  238 . The curved configuration  18  may be adapted for removal so that it may be replaced if desired. Suitable mating electrical contacts (not shown) are provided between the curved configuration and the associated distal end of the handle  14 . As previously mentioned, the wires  232  could be replaced by embedded ribbons, or by the cautery coils of description below. 
     FIG. 21 illustrates means for securing a cautery electrode in the form of a wire  242  within a groove  244  in a curved configuration  18 , while allowing the wire to be exposed along the length of the groove and curved configuration. To this end, a spaced series of counterbores  246  are formed, drilled, etc., through most of the curve cross-section in register with the groove  244  but leaving intact a portion  248  of the cross-section which abuts the wire  242 . A pair of wire-size bores  250  are formed or drilled at opposite sides of the diameter of the counterbore  246 , which bores penetrate into the groove  244  at opposite sides of the cautery wire  242 . A tie wire  252  is disposed about the cautery wire  242 , with the ends inserted through the wire-size bores  250  and twisted together a short length so as to be buried in the respective counterbores  246 . The series of tie wires  252  thus confine the cautery wire  242  within the groove  244 . The tie wires  252  may be tightly or loosely twisted. If loosely twisted, the tie wires allow axial or rotational movement of the cautery wire  242  with respect to the tie wires  252  and the groove  244 . This in turn provides means for cleaning or otherwise removing residual, charred, coagulated, entangled, etc., tissue and blood from the cautery wire  242 . Examples of such selfcleaning cautery wire embodiments are further discussed below. 
     FIGS. 22A,  22 B,  22 C and  22 D show alternative embodiments of a cautery curved configuration of the invention illustrating other means for confining a pair of exposed cautery electrodes or wires  256  in respective grooves  258  (FIGS. 22B,  22 C) in the curved configuration  18 . The confining means also can be used with a curved configuration having only one cautery wire. The curved configuration  18  is integrally formed with the rod  16 , in a selected configuration and angle such as disclosed here and in the other Figures. Conductors leading to the exposed cautery wires, or the cautery wires themselves, are embedded in the rod  16  or extend through a lumen therein. The cautery wires  256  are exposed via respective holes  259  at either side of the curved configuration  18  and extend therefrom within respective grooves  258  to the tip  19  of the curved configuration. As more clearly shown in the cross-sectional FIGS. 22B,  22 C, the grooves  258  and thus the cautery wires  256  exit the curved configuration  18  at opposite sides thereof as depicted in FIG.  22 B. The grooves gradually converge as they reach their midpoint in the region depicted in FIG. 22C, where the grooves  258  merge into a single wider groove and the cautery wires  256  extend side-by-side therein. The grooves and wires gradually diverge back to the opposite sides of the curved configuration at the tip  19  thereof. In this way, the position of the wires, and thus the direction of their exposure and the associated cutting and coagulating action of the instrument can be controlled. In this case, the cautery wire is further from the vessel which would generally be located inside the curved configuration  18  in the central section thereof, i.e. in the region of the section B—B, FIG.  22 A. 
     The wires  256  are retained in place in respective grooves  258  by a specially wrapped non-conductive line or thread  260  extending from prior to the exit holes  259  of the cautery wires to the tip  19  of the curved configuration. The cautery wires  256  can be rotated in place as depicted by arrows  262  to rotate the wires in their respective grooves thereby providing a self-cleaning action against the groove edges. Alternatively, or simultaneously, the wires  256  can be reciprocated longitudinally as depicted by arrows  264  to provide the self-cleaning action as they pass under the confining turns of the thread  260 . 
     FIG. 22D illustrates an alternative electrode confining means, namely, tie wires  266  in the form of individual rings spaced at selected intervals along the length of the curved configuration  18 , and secured about the circumference of the configuration and cautery electrodes to contain the electrodes in their respective grooves. Such individual tie wires  266  may be employed with any of the embodiments of description herein. 
     A mechanism for imparting the reciprocating movement to the cautery wire generally includes a stiff control wire extending through the handle  14  and attached at its proximal end to a spring loaded lever mounted in the handle. The spring maintains the cautery wire in a nominal position. Application of force on the lever overcomes the spring force and moves the cautery wire a selected distance to a second position. Rotation of the cautery electrode may include a slow speed motor housed in the handle  14  with an additional speed reducing gear arrangement coupled to a stiff wire. The cautery electrode wire (or coil) is suitably coupled to, but insulated from, the stiff wire, and is rotated upon the motor being energized. 
     FIG. 23 illustrates a further alternative embodiment of a cautery curved configuration employing a twisted, braided, etc. cautery electrode in the form of wire means  270  confined in a shallow groove  272  formed in a selected length of the curved configuration  18 . The cautery wire means  270  is confined in the shallow groove  272  by means of a spirally wrapped line or thread  274  extending over and beyond the length of the groove  272 , in a configuration similar to the confining means of FIG.  22 A. The twisted or braided cautery wire means  270  is exposed to surrounding tissue or side branches to provide the process of cutting and cauterizing. 
     In an alternative embodiment of FIG. 24A the spirally wrapped thread  274  is replaced by selectively confining the cautery wire means in a precisely sized groove  276 . That is, the diameter of the groove  276  and its depth into the curved configuration  18  cross-section is selected relative to the outside diameter of the twisted or braided cautery wire means  270  so that a narrow strip  278  of the cautery wire means protrudes from the configuration along its length to thus be exposed for electrical contact with adjacent tissue and side branches, while still being positively contained within the groove  276  as illustrated for example in FIG.  24 A. 
     As in the embodiment of FIG. 22A, the twisted or braided cautery wire means  270  may be rotated or reciprocated within the groove  272  or  276  as depicted by the arrows  279 , to provide the self-cleaning action of previous description. A mechanism for imparting rotating and/or reciprocating movement to the cautery wire is discussed above relative to FIG.  22 A. 
     FIG. 24B illustrates a further embodiment of a cautery electrode/curved configuration, wherein the major cross-section of the curved configuration  18  is formed by an electrically conductive cautery electrode  273 . A protrusion  275  is formed which extends a selected length of the curved configuration and provides electrical contact with side branches and connective tissue. An insulating coating  277  is formed over the remaining cylindrical surface to insulate the curved configuration  18 . 
     FIG. 25 illustrates a bi-polar coil configuration  280  for use in a cautery curved configuration in place of the various cautery wire configurations disclosed in the previous FIGS. 15-24 which, in general, depict a unipolar cautery wire configuration. The coil  280  is formed of a support tube  282  of a suitable insulating material, and selectively spaced wraps of a pair of coils  284 ,  286  which are partially embedded in the outer cylindrical surface of the insulating tube  282 . Coils  284  and  286  conduct electricity of opposite polarities to provide a bipolar cautery action between the coils. 
     FIGS. 26A-26D show portions of a curved configuration  18  illustrating various alternative embodiments of cautery electrodes formed of coils rather than the wires or ribbons of previous description. FIG. 26A illustrates an electrically energized cautery coil  300 , a major cross-section of which is embedded in a matching groove  302 . A portion of the coil  300  along its length is exposed to provide an exposed strip  304  for electrical contact with adjacent tissue and side branches. The coil diameter is relatively large with respect to the diameter of the curved configuration  18  and the groove is configured so that the coil  300  is confined within the configuration in the manner described in FIG. 24A, thereby dispensing with the tie wires or spirally wrapped threads, etc., of FIGS. 21,  22 ,  23 . As previously described, the coil  300  may be rotated or reciprocated to provide the self-cleaning action. In addition, since the coil forms in effect a continuous tube the sides of which are permeable to air, fluids, etc., the coil  300  may be used as a vacuum tube to provide smoke evacuation or a flood of fluid as depicted by arrow  305  and described in FIG.  19 . 
     By way of example only, a cautery electrode in the form of a coil such as described in FIGS. 26A-26D may be made of 0.010 inch diameter wire, wherein the wound coil measures 0.049 inch outside diameter. If the groove in which the 0.049 coil is embedded is of the order of 0.045 inch diameter, then the coil will be confined within the groove even when the coil is under considerable torque as when being rotated. See the wire electrode  270  and groove  276  of FIG.  24 A. 
     FIG. 26B illustrates a cautery coil electrode wherein a coil  306  is of smaller diameter relative to the diameter of coil  300  in FIG.  26 A. The curved configuration  18  is provided with a protruding portion  308  along the working length of the configuration, and a groove  310  is formed within the protruding portion. As in FIG. 26A, the groove  310  is of a diameter and is located relative to the outer surface of the protruding portion  308 , such that it confines the coil  306  within the curved configuration  18  while still exposing a strip  312  along the length of the coil to surrounding tissue and side branches. The coil  306  also may be used as a smoke evacuation tube and/or may be rotated or reciprocated to provide the self-cleaning action. 
     FIG. 26C illustrates an alternative embodiment of a cautery curved configuration  18  employing a pair of electrodes or coils  314 , 316  embedded in respective grooves  318 ,  320  in the manner described in FIGS. 26A or  26 B. The dual coil configuration allows the cutting and cauterizing process to be performed while moving the cautery curved configuration in either direction, without having to rotate the instrument. 
     FIG. 26D illustrates another alternative embodiment of a curved configuration  18  wherein a coil  322  is embedded in a groove  324 , wherein the groove and thus the coil location varies along the working length of the curved configuration  18 . More particularly, the coil  322  may initially exit from the curved configuration  18  at a top location  326  of the configuration cross-section. The groove and coil location then transitions from the top location to terminate at the tip  19  at an inside location  328 . Alternatively, the groove and coil may terminate at the front (leading) or side surface of the curved configuration  18  at the tip  19 . 
     FIG. 26E illustrates a modification to the cautery coil electrode configurations of, for example, FIGS. 26A-26D. A small tube  330  formed of an insulating and flexible material is formed with perforations  332  along its length. The tube  330  has an outside diameter and length to allow it to be inserted into the coils  300 ,  306 ,  314 ,  316  or  322  of previous description. The tube  330  is used for example to meter fluid evenly in or out of the coil area over the entire length of the coil and thus of the working area of the cautery curved configuration  18 . Thus the tube may be used for smoke or fluid evacuation, or may be used to supply a selected fluid evenly over the working area of the curved configuration. 
     FIGS. 27A and 27B illustrate still another embodiment of the invention suitable for delivery through a trocar port positioned in the patient&#39;s thoracic cavity for endoscopic surgery. This embodiment employs a retractable distal working end, that is, a retractable cautery curved configuration  340 , and includes a housing in the form of a tube  342  (only a distal portion is shown) which is coaxially formed or otherwise attached to a handle, such as shown in FIGS. 15,  17 ,  19 . The cautery curved configuration  340  is formed of a rod  344  of flexible and electrically non-conductive material. The rod  344  is consecutively notched as at  346  to permit easier deformation thereof into a predetermined curved configuration. A wire  348  is embedded into the rod  344  and is formed, for example, of a nickel-titanium alloy material having an inherent shape-memory property. That is, once the material is pre-formed into a predetermined shape application of an associated electrical current will cause the material to return to its predetermined shape. The material thus is similar to that described in the invention embodiment of previous FIGS. 6-9. In this embodiment, the nickel-titanium alloy wire  348  in the working end of the rod  344  is preformed to define the predetermined curved configuration  340 . 
     FIG. 27A depicts the rod  344  as it is being extended from the protective housing of the tube  342  (arrow  350 ). Upon full extension, application of an electrical current to the nickel-titanium alloy wire  348  by a suitable energy source (not shown) via a conductor  352 , causes the pre-formed portion of the wire  348  in the working area to return to its predetermined curved configuration, as shown by arrow  354  in FIG.  27 B. 
     Although a cautery electrode is not shown in the retractable embodiment of FIGS. 27A,  27 B, it is to be understood that a cautery wire or coil may be embedded along the centerline surface of the rod  344  in the working area of the curved configuration  340  in the manner variously described in the previous FIGS. 15-26E. 
     FIG. 28 illustrates an alternative embodiment of the retractable curved configuration  340  of FIGS. 27A,  27   b  wherein a rod  356  similar to the rod  344  includes a nickel-titanium alloy wire  358  embedded in the working end thereof. In this embodiment the wire  358  is pre-formed into a predetermined configuration  362  which also is bent at a selected angle (arrow  360 ) relative to the center-line of the handle and housing tube  342 . The added angle allows the instrument to be used in retrieval takedown procedures for a vessel  26  such as the LIMA when the vessel extends parallel to the center-line of the instrument. Such a curved configuration also is shown and described in previous FIGS. 18A,  18 B. 
     FIGS. 29A through 31 illustrate a further alternative embodiment of the invention employing a pre-formed curved configuration  370  generally similar to the curved configuration  340  of FIGS. 27A,  27 B, but wherein the curved configuration is established by means of selective notches and a pull-wire assembly. More particularly, the curved configuration  370  is formed of a rod  372  of flexible and electrically non-conductive material. The rod  372  is notched as at  374  in an upper portion thereof at the proximal end of the curved configuration  370  itself. The rod is also notched along the lower portion thereof for the length of the curved configuration  370 , as indicated at  376 . The notches  374  and  376  thus determine the eventual shape of the curved configuration  370 . A relief bore  378  is formed through the rod cross-section at the apex of each notch  374 ,  376  to facilitate the desired bending of the rod into the curved configuration  370 . A pull-wire  380  is embedded within a lumen  382  within the rod  372  along generally the centerline thereof. A distal end  384  of the pull-wire  380  is anchored at the tip  19  of the rod  372 , that is, of the curved configuration  370 . In FIGS. 29A,  29 B the pull-wire  380  extends through the lumen  382  in the rod  372  to a locking mechanism  386  disposed here at the proximal end of the rod. The locking mechanism  386  includes a proximal end of the pull-wire  380  extends. A locking/unlocking cam  388  with wire-engaging serrations is pivotally secured in the mechanism above the pull-wire. When the cam  388  is raised to disengage it from the pull-wire (arrow  390 , FIG. 29A) the pull-wire  380  may be translated within the lumen  382 . To form the curved configuration  370  of FIG. 29B, the pull-wire  380  is pulled proximally (arrows  392 ), whereupon the cam  388  is pivoted down to engage the pull-wire (arrow  394 ) to lock the shape of the curved configuration  370 . A cautery wire, ribbon, etc., electrode  396  is selectively contained by the curved configuration  370 , as described in previous figures, to provide the cutting and cauterizing functions. 
     FIG. 30 illustrates a modification to the notch configuration of the previous FIGS. 27A-29B wherein the notches  374  and/or  376  are provided with an interlocking V-groove configuration to increase the lateral stability of the curved configuration  370  when locked in place. 
     FIG. 31 illustrates an alternative embodiment of a curved configuration electrosurgical instrument in accordance with the invention embodying the features of FIGS. 29 and 30. The instrument includes a handle  398 , equivalent to the handle  14  of FIGS. 15A,  17 A,  19 A,  19 B and  20 , and coupled at its distal end to a preferably malleable, elongated shaft  400 . The curved configuration  370  of FIGS. 29,  30  is secured to, or formed with, the distal end of the shaft  400 . The pull-wire  380  extends within the length of the shaft and through the handle  398  to terminate at a locking mechanism  402  the equivalent of the mechanism  386  of FIGS. 29A,  29 B. The locking mechanism  402  also includes means for pulling the attached pull-wire  380  into the handle  398  prior to locking the pull-wire, and thus the curved configuration  370 , in place. The cautery electrode  396  is electrically energized by means of an electrical conductor extending therefrom through the shaft  400 , and a pair of electrical button switches  404 ,  406  similar to the switches  237 ,  239  of FIG.  19 B. Suitable electrical energy is supplied to the switches  404 ,  406  via an electrical cord  408  extending from the proximal end of the handle  398 . The malleable shaft  400  allows the instrument to be bent into a desirable shape. 
     Although the invention has been described herein relative to specific embodiments, various additional features and advantages will be apparent from the description and drawings, and thus the scope of the invention is defined by the following claims and their equivalents.