WO1995014435A1

WO1995014435A1 - Endocospic surgical instrument

Info

Publication number: WO1995014435A1
Application number: PCT/US1994/013150
Authority: WO
Inventors: John Kirwan; Matthew V. Lyons
Original assignee: Brimfield Precision Incorporated
Priority date: 1993-11-23
Filing date: 1994-11-18
Publication date: 1995-06-01

Abstract

The invention features a medical instrument (10) comprising an elongate tube (14) defining a channel and having an interior and an exterior, and plural through apertures (24) spaced at intervals along the length of the tube, each through aperture defining a flow path between the interior and exterior. The distal end of the instrument has an end effector controlled by a handle (34) at the proximal end. The instrument further includes an insulating sheath (26) over the tube that key locks over a rotary joint at the proximal end and controls access to a cauterizing socket (80) so as to prevent electrical energization when the insulating sheath (26) is not over the tube (14). The rotary joint is indexed and communicates with the handle and a set of finger control loops (94, 96) so as to provide plural rotary positions for the handle relative to the end effector. The handle positions are lockable, or not, under the control of a set of pawls in a lever (108). A plurality of pawls (106, 107) associated with the lever (108) allows a great range of lock positions.

Description

ENDOSCOPIC SURGICAL INSTRUMENT

FIELD OF THE INVENTION The invention relates to the field of medical instruments, and particularly to the field of endoscopic surgery medical instruments.

BACKGROUND OF THE INVENTION

For medical procedures involving surgery, medical devices which require manual manipulation at one end to effect a result at another end via a long extension are frequently used, e.g., in arthroscopic and endoscopic surgery.

Typically, endoscopic and arthroscopic devices are relatively small and are used in surgical procedures where a long narrow tubular device provides access to tissue within the body with minimal disturbance of adjacent tissue. Encoscopic devices are normally difficult to manipulate during surgery, and are also difficult to clean due to the narrow diameter and extended length of the tube, the interior of which may come into contact with contaminated tissue or body fluids. In many endoscopic procedures, a small incision may be made in the skin of a patient, along the abdomen, for example, and the sharp point of a larger penetrating instrument, such as a trocar of suitable length and diameter, is inserted into the incision and pushed until the point punctures the cavity wall. For example, laparoscopy is a well know method of visually examining the peritoneal cavity by means of a long slender endoscope equipped with sheath, obturator, biopsy forceps, a sphygmo-manometer bulb and tubing, and a syringe. Normally, a sleeve is fitted over the exterior surface of the instrument to serve as a lining for preserving the shape of the passageway created by the instrument. After the sleeve is in place, the instrument may be withdrawn and an endoscope, forceps or other surgical instruments may be inserted via the sleeve to view and operate upon organs within the cavity. Many surgical instruments for use in endoscopy utilizing, for example, forceps or cutting instruments, incorporate a knob-like handle attached to a shaft, or a pistol-like handle which includes a protrusion or abutment on the pistol-like handle in order to receive the thumb of the surgeon. Such instruments are limited in their manipulability. The area in which the surgeon must perform procedures incorporating endoscopic surgical instrumentation is confined, and smaller than that normally encountered when conventional surgical techniques are employed. Thus, reliance by the surgeon upon touch and feel during the surgery is critical, and surgical instrumentation must accomodate restraints in which delicate manipulations are easily performed from a distance and within a confined area.

Accordingly, one object of the invention is to provide a surgical instrument which utilizes efficient mechanical design so as to allow for maximal manipulation in a relatively confined area of the body. Another object is to provide an instrument which is capable of securely locking into one of many selected positions for an extended period of time. Another object is to provide a forcep-like instrument which is capable of grasping tissue securely in a confined area and at differing angles, while allowing for relatively free movement of the operator. Yet another object is to provide an electro-cautery surgical instrument which gives insulating protection to the user and the patient. A yet further object of the invention is to permit the cleaning of even obscured part of such an instrument where body contaminants might be found.

BRIEF SUMMARY According to the teaching of the present invention, a surgical tool is provided having an end effector such as a gripper, cutter, punch or separator located at the distal end of a long tube and a pair of scissor-like grippers in a handle located at the proximal end of the tube with a control mechanism in between. The end effector is typically provided according to the designs represented by United States Patent Application Serial No. 07/883,080 filed May 15, 1992. The elongated tube which separates the end effector at the distal end from the manual controls at the proximal end is typically formed with elongate-side apertures and covered by an insulating sheath. The insulating sheath permits electrification of the end effector for such purposes as cauterization at the point of the end effector tool without applying electrical potential to any body passages through which the tube traverses in the body. The apertures in the tube permit more complete washing and flushing of the internal tube components during cleaning to prevent contaminated body fluids with dangerous virus or other microreable material being retained therein during conventional washing. The end effector at the distal end is activated by a rod which passes through the elongated tube and is exposed by the elongated apertures therein to assist in cleaning. The control rod is activated for axial displacement to control the opening and closing or other motion of the tool at the end effector by a first pivoting finger grip in the end handle. A second, fixed finger grip permits the operator to manually control the moveable finger grip and, in turn, the axial motion of the control rod as in scissor fashion. The moveable finger grip is lockable in a plurality of different positions by a rachet mechanism comprising a set of teeth fixed to the moveable finger grip near a pivot point therefor and a plurality of pawls, offset with respect to each other so that they fit into the teeth at respective different positions to provide a multiplication of the number of fixed points at which the moveable grip may be locked. The pauls are pivoted on a release trigger which protrudes from the handle just above the position of the moveable grip and is itself pivoted within the handle and biased by a spring mechanism into a first position in which the pawls are operative to lock into the teeth of the moveable grip and a second position in which the pawls are held above the teeth so that the moveable grip moves freely without any locking effect. The placement of the trigger release is such as to allow the operator to easily manipulate it with one of the digits of the hand. The linkage between the moveable grip and the control rod is rotary, allowing the control rod to rotate about its axis of motion so that the end effector can be positioned at different angles about the axis of the control rod and the elongate tube. Between the handle and the elongated tube is an assembly which serves to permit the insulating sleeve to be removed, which provides for a terminal for electrification of the end effector with an insulating safeguard preventing shock to the patient as well as preventing electrification when the insulating sheath is removed, and provides for a series of detents defining stable angles of rotation for the end effector and elongated tube, such as at every thirty or forty-five degrees.

DRAWINGS Fig. 1 is a side view of a medical instrument of the invention, showing forceps or grippers as the end effector in the open position.

Fig. 2 is a side view of a medical instrument of the invention, showing forceps in the closed position. Fig. 3 is a side view of an unsheathed portion of an instrument according to the invention.

Fig. 4 is a cross-sectional view along plane 4-4 shown in Fig. 1 of the tube of an instrument according to the invention. Fig. 5 is a cross-sectional view along plane 5-5 shown in Fig. 1 of the tube of an instrument according to the invention.

Fig. 6 is a partial sectional view of the body of the body of the interior between handle and elongate tube of an instrument according to the invention.

Fig. 7 is a partial sectional view of the handle of an instrument according to the invention in an unlockable state.

Fig. 8 is a further partial sectional view of the handle of an instrument according to the invention in an unlockable state.

Figs. 9A, 9B and 9C are side elevation views of the ratchet locking mechanism within the handle of an instrument according to the invention in various locked positions. Fig. 10 is a side elevation view of the ratchet locking mechanism within the handle of an instrument according to the invention in an unlockable state.

DESCRIPTION Referring to Figs. 1, 2, and 3 medical instrument 10 includes handle 34 at one end, intermediate portion 32 defining an interface between the handle 34, and a driver 89 with enlongated, sheathed tube 14 terminating at the distal end 20 with an end effector tool, here shown with gripperε tongs 91, 91'. Driver rod 89 is slidably positioned within tube 14 (Fig. 3) . Tube 14 is protected by a covering sheath 26. Tube 14, shown in Fig. 3, has an exterior surface 16 and an interior surface 18 and distal end 28 and proximal end 22, and defines an internal channel for a driver rod 89 to activate tool elements 91, 91'. Referring to Fig. 3, tube 14 contains plural elongate through-apertures 24 spaced at intervals along its length, each aperture allowing communication between the exterior 16 and interior 18 surfaces of tube 14 and around rod 89. Sheath 26 is closely fitted over tube 14 such that the internal surface of the sheath is in intimate contact with the external surface of the tube. Thus, if liquid is passing through the internal volume of the tube while the sheath is fitted in place, then no liquid will pass through the apertures to the exterior of the tube. As shown in Figs. 1 and 2 and discussed more fully below, rod 89 cooperates with handle 34; that is, when scissors loop 94 of handle 34 is pushed away from loop 96, driver rod 89 retracts into tube 14 such that grippers 91,91' are in the open position (Fig. 1) , and when scissors loop 94 is pulled on loop 96, driver 89 pushes out of tube 14 such that forceps grippers 91,91' are in the closed position (Fig. 2) . Exemplary tool mechanics are shown in the above cited U.S. Patent application, incorporated herein by reference. Figs. 4 and 5 show the tube 14 and sheath 26 of instrument 10 in cross-section along planes 4-4 and 5-5, respectively. Also shown in Figs. 1 and 2 is the interface provided by intermediate portion 32, illustrated in detail in Fig. 6, which connects end 22 to handle 34 of medical instrument 10. Sheath-wheel 36 extends from sheath 26 over part of intermediate portion 32. The wheel 36 and sheath 26 are preferably formed as one unitary piece.

Sheath 26, with wheel 36, of medical instrument 10 is slidably removable for easy cleaning of tube 14. Sheath 26, when fitted around tube 14, electrically isolates the exterior surface 16 of tube 14 from the external environment particularly body parts. Sheath 26 and sheath-wheel 36 are made of electrically non-conductive material such as plastic, and thus act as insulators.

Referring to Fig. 6, a sheath-wheel 36 is provided at the proximate end of sheath 26 and fits snugly around rotator disk or cup 50 of intermediate portion 32. Tube 14 is secured to the cup 50 and activating rod 89 passes through it. Along the inner surface 53 of the wheel edge are located several fingers 52 which are shaped so as to fit into corresponding notches 54 extending partially along outer surface 51 the cup 50 from the proximal end. Adjacent notches 54 are grooves 55 allowing fingers 52 to slide axially the length of cup 50 for installation or removal. A spring 56 holds the fingers 52 in notches 54 after they are slid the length of grooves 55, and, by rotation of wheel 36 allowed to slip into notches 54. Thus, the sequential pushing and turning motion of the wheel 36 allows the fingers 52 to fit into corresponding notches 54, and thus locks the wheel into place. To remove the wheel and sheath, the wheel 36 is pushed proximally to cause fingers 52 to exit notches 54 and turn in the opposite direction to allow fingers 52 to slide the length of grooves 55 to release the wheel 36 and sleeve 26.

Rotator spring 56 abuts at one end against abutment 58 on the inside of sheath-wheel 36 and at the other end against rotator cup 50. Thus, when sheath 26 is secured in place by sliding over tube 14, sheath-wheel 36 is pushed against rotator spring 56 with fingers 52 in grooves 55 all the way until they exit at the proximal end. Then with a rotation of wheel 36 fingers 52 are allowed to slide into notches 54, in a click-stop motion. Optimally, sheath-wheel 36 will include three equally spaced fingers 52 located circumferentially on the wheel, only one of which is visible in Fig. 6. There are the three grooves 55 and three notches 54 equally spaced from each other. When sheath-wheel 36 is in place, spring 56 is coiled under pressure and this tension forces sheath-wheel 36 in the direction of distal end 20. Sheath-wheel 36 cannot slide off intermediate portion 32 due to fingers 52 secured in notches 54. Sheath 26 is removed by pushing the wheel 36 against the coiled tension of spring 56 in the handle direction, and rotating the wheel 36 enough to allow fingers 52 to disengage from the corresponding notches 54.

Referring to Fig. 6, an indexing sleeve 60 is positioned around activating rod 89, proximal of cup 50, and includes a central portion integral with forward and rear projections 61 and 61'. Rotator cup 50 and indexing sleeve 60 form a two-piece construction which is axially secured together via slip fit pin 62. Pin 62 fits through a hole 63 in cup 50 and locks indexing sleeve 60 in a circular groove 64 to allow rotary movement of cup 50 and indexing sleeve 60. Indexing sleeve 60 is able to rotate, clockwise or counter-clockwise, relatively friction-free in opposition to rotator cup 50 but is held in stable indexed locations by a ball 66 in sockets 65, 65', 65", 65'", etc., cut into the distal facing surface of sleeve 60 where it abuts rotator cup 50. These sockets are typically 8 or 12 in number and are equally spaced in a circle. Ball 66 is urged into a socket by a spring 68 in a bore of rotating cup 50. Spring 68 pushes ball 66 into one of sockets 65, 65', 65", 65'"; thus, the spring/ball combination acts as a detent to retain rotating cup 50 in place against indexing sleeve 60. Upon rotation of rotator cup 50 with respect to indexing sleeve 60, ball 66 slips out of one socket 65 and into the next socket 65', allowing rotator cup 50 to assume as many stable rotational positions with respect to indexing sleeve 60 as there are sockets. The invention thus provides for rotational capability about the longitudinal axis of instrument 10.

Referring again to Fig. 6, cautery plug 70 provides for electrical connection of instrument 10 to an electrical source. Plug 70 inserts into plug receptacle 80 in sleeve 60 through a hole 78, in cautery plug cuff 72, which fits closely around indexing sleeve 60. Cuff 72, made of an electrically non-conductive material, is urged by the force of a sleeve spring 74 as it abuts cuff 72 at one end and annular spacer 76 at the other end to move to cover recess 80 where wheel 36 is removed, preventing insertion of the plug 70 in that case. With a plug 70 inserted, wheel 36 cannot be moved sufficiently to clear fingers 52 from notches 54. Spacer 76, which is made of an electrically non- conductive material, abuts handle 34 and thus acts as an insulator which prevents electricity coming into instrument 10 via plug 70 from conducting to an operator near handle 34. Because instrument 10 is utilized in connection with electrical means via cautery plug 70, and acts as a conductor for electrical energy used in cauterizing along tube 14, an additional safety means prevents use of the instrument without first securing the insulating sheath 26 in place. This safety means is found in the opposing interaction of sheath-wheel 36 and cautery plug cuff 72, both of which are insulators. When sheath 26 and sheath-wheel 36 are in place on the instrument, sheath-wheel 36 abuts cautery plug cuff 72 such that the insulating effect is continuous over the surface of instrument. When sheath-wheel 36 is turned into click-stop position, it forces cuff 72 against spring 74 such that hole 78 in cuff 72 is aligned with plug receptacle 80 to allow insertion of plug 70. The electrical connection provided by plug 70 is prevented when sheath 26 is removed, since the sheath-wheel 36 is not present to force cuff 72 back to allow alignment of hole 78 with plug receptacle 80. Misalignment of hole 78 and receptacle 80 prevents plug 70 from entering the recess 80 and completing an electrical connection without the sheath 26 being in position. An additional safety mechanism exists while plug 70 is in place in hole 78; that is, sheath 26 and sheath-wheel 36 cannot be removed without first removing plug 70 from hole 78, since sheath-wheel 36 must be pushed against cuff 72 to unlatch fingers 52 from notches 54, which in turn forces cuff 72 against spring 74 and misaligns holes 78 and 80. Thus, holes 78 and 80 are misaligned when sheath 26 sheath-wheel 36 are removed, and also when sheath-wheel 36 is being secured into position. Holes 78 and 80 are aligned and thus available for insertion of plug 70 into position only when sheath-wheel 36 is secured into click-stop position.

Activating rod 89 slides within tube 14 and is able to slide and turn by virtue of a rotary connection with the scissor loop 94 with handle 34. Although the distal end 20 of driver rod 89 is shown to have forcep strips, in fact, this effector end may be any type of instrument, e.g., a surgical gripper, a cautery instrument, e.g., electro- cautery, a needle, scissor blades, a punch, a suction instrument, etc., with appropriate modifications. Although the distal end 20 of instrument 10 in the figures is depicted as a forceps, and thus the description directed to operation of a forceps, the instrument described herein is not meant to be limited to forceps operation. As shown in Fig. 1, movement of driver rod 89 back into tube 14 opens gripping tongs 91, 91' so as to grasp tissue; movement of driver 89 forward out of tube 14 allows tongs 91, 91' to move toward each other and thus to grip tissue. Rotational movement of wheel 36 relative to the handle 34 and the coordinate rotation of driver rod 89 allows tongs 91, 91' to assume a horizontal or vertical position with respect to the handler 34, or any position between horizontal and vertical.

Referring to Figs. 7 and 8, handle 34 includes scissor loops 94 and 96 for insertion of index finger and thumb, respectively, scissor loop 96 is stationary with handle 34, whereas loop 94 moves pivotally. Referring also to Figs. 9A, B and C, scissors loop 94 is secured in place via slip-pin 100 which in turn is tightened or loosened via set screw 114. Slip-pin 100 slides through a hole in head 98 and thus acts as a fulcrum allowing lateral, pivotal movement of loop 94 around pin 100. Head 98 also includes a cam 102 which fits between driver 89 and the fixed extension 92 of driver 90. Thus, lateral movement of loop 94 towards or away from loop 96 results in force being applied against driver 89 via cam 102 or resting in a recess in driver rod 89 between cheeks 92. The position of the driver may be secured via the ratchet locking mechanism, which includes ratchet teeth 104, pawls 106 and 107 and release lever 108. The ratchet locking mechanism, the driver rod 89 and a portion of the cuff 72 are all located within handle 34, as shown in Figs. 7 and 8. Locking may occur in several positions, depending upon the relative positions of loop 94 and lever 108. In Figs. 1 and 7, loop 94 and lever 108 are positioned so as to lock ratchet teeth 104 in a position which applies force pulling back driver 89. Alternatively, in Figs. 2 and 8, loop 94 and lever 108 are positioned so as to lock ratchet 104 in a position which applies force toward driver 89. Referring to Figs. 9A, B and C, the ratchet lock is shown in the process of tightening in lockable states, and in the unlocked state in Fig. 10. Lever 108 is pivoted to handle 34 via a pin 112 at location 109. The lever 108 has two stable positions with respect to handle 34 secured via a ball 120 urged against detents 121 by a spring in a set screw 118 (Fig. 9A) . Set screw 118 is in turn secured in handle 34. Set screw 118 thus interfaces with the locking mechanism so as to help stabilize it in a locked or unlocked position. When the locking mechanism is in a locked position, pawls 106, 107 are in contact with the teeth 104 of the ratchet to provide locking. Pawls 106, 107 are similar in shape, but have their points of contact with teeth 104 staggered. Pawl 106 is slightly longer than Pawl 107 by half the distance between teeth 104. The staggered locking point of pawls 106, 107 thus allow locking twice as often as a single pawl would, and provides twice as many index locked positions for manual operation of loops 94, 96.

Pawls 106, 107 are secured to lever 108 via a pivot pin 112 which is held in place by set screw 116. Pawls 106, 107 are urged against teeth 104 by wire spring 124, which is looped around pin a 122. In the unlocked position of lever 108 shoulders 123 lift pawls 106, 107 away from contact with teeth 104. Lever 108 is operated by the pressure of an index finger on its distal end, and thus may be pulled towards loops 94, 96 into locking position (i.e., lever down position), or it may be pushed away from loops 94, 96 into unlocked position (i.e., lever up position). Thus, when lever 108 is in the up position, the lock is off, and when lever 108 is in the down position, the lock is on. Medical instrument 10 may be obtained as a medical kit which includes the packaged medical instrument. The medical instrument may be pre-assembled in the kit, i.e., the sheath 26 is fitted around the tube 14 so that the instrument 10 is ready for use once the packaging is removed. Alternatively, instrument 10 may be obtained in unassembled form and thus may contain a separately packaged sheath 26. In the unassembled kit, the packaging is removed from each of the sheath 26 and the tube 14, and the sheath is slidably fitted over the tube. The medical kit may further include a cleaning solution. Instrument 10 is particularly useful in laparoscopic surgery or where it is necessary to provide uniformly spaced and uniformly long incisions or cauterization.

In operation, medical instrument 10 is sterile and is inserted in sheathed form into the body, typically with gripping tongs 91, 91' retracted and locked as in Fig. 2, and manipulated via handle 34 at the distal end 20 of tube 14 in surgery. Normally, instrument 10 will be inserted into the body with cautery plug 70 inserted in holes 78 and 80, ready for electrical use. The tongs 91, 91' open under spring force when the lever 108 is unlocked. Wheel 36 is rotated to align the tongs for gripping. • The syrgeon manipulates the rest of the instrument with the thu7mb inserted into loop 96 and finger into loop 94; another finger is resting on lever 108, which initially may be in the unlocked (i.e., upward) position (Fig. 10B) . Thus, with tissue to be gripped (cut, punched, etc.) by squeezing loop 94 toward loop 96, in the direction shown in Fig. 7, head 98 is rotated around pin 100 and cam 102 pushes against driver 89 and toward the distal end 20 of instrument 10. When driver 89 is in the forward position, tongs 91, 91' are in the closed position.

The tissue may be fully released from grasp of the tongs by moving lever 108 upward to pawls 106, 107 so that they are no longer forced into contact with ratchet teeth 104. Release of the tissue may then be followed by removal of instrument 10 from the body. After surgery is complete and instrument 10 is removed from the body, the instrument is cleaned in preparation for further use. Cleaning of instrument 10 is accomplished by first removing cautery plug 70 from holes 78 and 80. Sheath- wheel 36 is then pushed toward and against cuff 72 and twisted such that fingers 52 are moved out of position in notches 54. Sheath 26 with its wheel 36 are then slidably removed by moving fingers 52 in grooves 55 and by moving the sheath and wheel along tube 14 towards distal end 20. The instrument 10 minus sheath 26 and wheel 36 is then cleaned by flowing a cleaning solution over it and into the interior of tube 14 via apertures 24. During flow of the cleaning solution through tube 14, remnants of body tissue and body fluids are swept out of the interior of tube 14. In addition, flow of the cleaning solution through the apertures and along the exterior surface 16 of tube 14 sweeps tissue and body fluids from the tube 14 external surface 16.

All elements of the instrument except the sheath, sheath-wheel, and cuff are typically made from high grade surgical stainless steel. Sheath 26 and sheath-wheel 36 may be injection-molded using non-conductive material, typically teflon. Cuff 72 is also made from non-conductive material, e.g., teflon.

The invention may be embodied in other forms without departing from the spirit of the invention, as described herein. The described embodiments are to be considered as illustrative and are not intended to restrict the scope of the invention. Other aspects, advantages, and objects of the invention are embraced within the following claims.

Claims

1. A medical instrument comprising: an elongate tube defining a channel and having an interior and an exterior, and plural through-apertures spaced at intervals along the length of said tube, each said through-aperture defining a flow path between said interior and exterior; an end effector at a distal end of said tube; a hand control for said end effector at a proximal end of said tube; and an activating rod connecting said end effector and said hand control through said tube and exposed through said apertures.

2. The instrument of claim l, further comprising: an elongate removable sheath having distal and proximal open ends, fitted closely around said tube so as to electrically insulate said tube.

3. The instrument of claim 2, said tube further comprising distal and proximal ends and, ^' extending from said tube proximal end, means for rotatably attaching said tube to said handle.

4. The instrument of claim 3, further comprising: an insulating wheel extending from said sheath proximal end; a disk attached to said tube and selectively covered by said wheel; and a rotary joint formed between said handle and said disk imparting indexing of positions to rotation between said handle and said tube.

5. The instrument of claim 4 wherein said wheel further comprises means for anchoring said wheel to said disk.

6. The instrument of claim 5, wherein: said wheel and disk have relatively keying and spring loading that permits the wheel to slide over the disk against a spring force in one key position and to be held with the wheel covering the disk in a second key position.

7. The instrument of claim 6 further including a cover protecting a cautery plug socket electrically connected to said tube at said rotary joint and accessible through said cover only when said wheel is in said second key position.

8. The instrument of claim 6 wherein: said rotary joint has a covering and spring urging it over the rotary joint against the wheel; said rotary joint has an aperture for accepting a cauterizing plug; and said covering has an aperture aligned with said joint aperture only when the covering is urged against said spring by said wheel being in the second key position.

9. The instrument of claim 1 wherein said hand control includes: a handle and finger loop associated therewith; a second finger loop pivoted to said handle and engaging said activating rod for axial motion through said tube to control said end effector thereby; a locking mechanism for said second loop having a plurality of locking fingers engaging a set of teeth at different positions for each finger to provide more locking positions than the number of teeth over a predetermined range of positions for said second loop.

10. The instrument of claim 9 wherein said locking mechanism includes: a locking control lever having a plurality of pawls pivoted thereon, each pawl carrying one of each of said fingers; a surface on said second loop within said handle proximate the pawls of said lever, said surface bearing said teeth.

11. A medical instrument comprising: an elongate tube defining a channel and having an interior and an exterior; an end effector at a distal end of said tube; a hand control for said end effector at a proximal end of said tube; and an activating rod connecting said end effector and said hand control through said tube and exposed through said apertures. an elongate removable sheath having distal and proximal open ends, fitted closely around said tube so as to electrically insulate said tube.

12. The instrument of claim 11, said tube further comprising distal and proximal ends and, extending from said tube proximal end, means for rotatably attaching said tube to said handle.

13. The instrument of claim 12, further comprising: an insulating wheel extending from said sheath proximal end; a disk attached to said tube and selectively covered by said wheel; and a rotary joint formed between said handle and said disk imparting indexing of positions to rotation between said handle and said tube.

14. The instrument of claim 12, said disk comprising an annular groove and said rotary joint comprising a hole , wherein a pin is inserted through said hole and against said groove so as to rotatably join said disk to said rotary joint.

15. The instrument of claim 13 wherein said wheel further comprises means for anchoring said wheel to said disk.

16. The instrument of claim 15, wherein: said wheel and disk have relatively keying and spring loading that permits the wheel to slide over the disk against a spring force in one key position and to be held with the wheel covering the disk in a second key position.

17. The instrument of claim 16 further including a cover protecting a cautery plug socket electrically connected to said tube at said rotary joint and accessible through said cover only when said wheel is in said second key position. i

18. The instrument of claim 16 wherein: said rotary joint has a covering and spring urging it over the rotary joint against the wheel; said rotary joint has an aperture for accepting a cauterizing plug; and said covering has an aperture aligned with said joint aperture only when the covering is urged against said spring by said wheel being in the second key position.

19. The instrument of claim 11 wherein said hand control includes: a handle and finger loop associated therewith; a second finger loop pivoted to said handle and engaging said activating rod for axial motion through said tube to control said end effector thereby; a locking mechanism for said second loop having a plurality of locking fingers engaging a set of teeth at different positions for each finger to provide more locking positions than the number of teeth over a predetermined range of positions for said second loop.

20. The instrument of claim 19 wherein said locking mechanism includes: a locking control lever having a plurality of pawls pivoted thereon, each pawl carrying one of each of said fingers; a surface on said second loop within said handle proximate the pawls of said lever, said surface bearing said teeth

21. A medical instrument comprising: an elongate tube defining a channel and having an interior and an exterior; an end effector at a distal end of said tube; a hand control for said end effector at a proximal end of said tube; and an activating rod connecting said end effector and said hand control through said tube and exposed through said apertures; said hand control including a handle and finger loop associated therewith; a second finger loop pivoted to said handle and engaging said activating rod for axial motion through said tube to control said end effector thereby; a locking mechanism for said second loop having a plurality of locking fingers engaging a set of teeth at different positions for each finger to provide more locking positions than the number of teeth over a predetermined range of positions for said second loop.

22. The instrument of claim 21, further comprising: an elongate removable sheath having distal and proximal open ends, fitted closely around said tube so as to electrically insulate said tube.

23. The instrument of claim 22, said tube further comprising distal and proximal ends and, extending from said tube proximal end, means for rotatably attaching said tube to said handle.

24. The instrument of claim 23, further comprising: an insulating wheel extending from said sheath proximal end; a disk attached to said tube and selectively covered by said wheel; and a rotary joint formed between said handle and said disk imparting indexing of positions to rotation between said handle and said tube.

25. The instrument of claim 24 wherein said wheel further comprises means for anchoring said wheel to said disk.

26. The instrument of claim 25, wherein: said wheel and disk have relatively keying and spring loading that permits the wheel to slide over the disk against a spring force in one key position and to be held with the wheel covering the disk in a second key position.

27. The instrument of claim 26 further including a cover protecting a cautery plug socket electrically connected to said tube at said rotary joint and accessible through said cover only when said wheel is in said second key position.

28. The instrument of claim 26 wherein: said rotary joint has a covering and spring urging it over the rotary joint against the wheel; said rotary joint has an aperture for accepting a cauterizing plug; and said covering has an aperture aligned with said joint aperture only when the covering is urged against said spring by said wheel being in the second key position.

29. The instrument of claim 28 wherein said locking mechanism includes: a locking control lever having a plurality of pawls pivoted thereon, each pawl carrying one of each of said fingers; a surface on said second loop within said handle proximate the pawls of said lever, said surface bearing said teeth.