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Anti-Arcing Loop and Resectoscope
0022-534 7/78/1194-0534$02. 00/0
Vol. 119, April Printed in U .SA.
THE JOURNAL OF UROLOGY
Copyright © 1978 by The Williams & Wilkins Co.
ANTI-ARCING LOOP AND RESECTOSCOPE JOSE J. IGLESIAS, SNAPRASAD C. MADDURI, ORLANDO PETTIROSSI, ANDREW SPORER AND JOSEPH J. SEEBODE From the Department of Surgery (Urology), New Jersey Medical School, Martland Hospital and Affiliated Hospitals, the Urological Services, East Orange Veterans Administration Hospital, Newark, New Jersey, and the Instituto di Clinica Chirurgia, Trieste, Italy
ABSTRACT
A new modified cutting loop assembly and a modification of the resectoscope to prevent arcing between the bare wire loop and the distal end of the telescope are described. end of the telescope backward within the sheath but this procedure diminishes the field of endoscopic operative vision, 2) reducing the proximal movement of the cutting loop assembly in order to maintain a safe distance between the bare loop and the telescope and 3) extending the insulation of the spaced parallel arms of the loop assembly over and beyond the junction of the arms and the dependent loop but this procedure diminishes the depth of the resected pieces. These methods not only fail to prevent arcing but also reduce the efficiency of
When a transurethral operation is done with a resectoscope electrical arcing may occur between the uninsulated distal ends of the arms or the upper ends of the bare wire cutting loop and the adjacent distal end of the telescope. This arcing happens when the cutting loop assembly is moved to rest position and the end of the telescope is touched by a piece of incompletely resected tissue that has adhered to the cutting loop (part A of figure) or by the bare wire of a broken or deformed cutting loop. In the conventional loop the cutting
I
f
A, conventional loop and resectoscope. Electrical arcing may occur between uninsulated loop and telescope by piece of incompletely resected tissue that has adhered to cutting loop. B, anti-arcing loop and resectoscope. Loop arms are extended distally, bare wire loop is spaced from telescope when loop is in rest position. Telescope is protected by distal extension of tube that supports telescope. C, anti-arcing loop and resectoscope. New backward inclined position of bare wire loop. During resection this design causes bottom ofloop to enter first into insulated fenestra, initiating and assuring completely clean cut ofresected tissue with each excursion.
loop is in a vertical position and is easily deformed. The electrical arcing may damage the telescope, adversely affect the operative procedure and, possibly, cause injury to the surgeon. There have been several reports on eye injuries to surgeons doing transurethral operations, 1 and it is well known that surgeons have experienced electrical shocks and burns of the hands, cheeks, nose or ears because of arcing during an operation with the resectoscope. Among the methods suggested to correct these difficulties are 1) positioning the distal Accepted for publication June 10, 1977.
the instrument. Any modification of the resectoscope to prevent arcing should maintain the wide angle vision provided by modern optic systems and should not decrease the length of the cut at each stroke of the cutting loop. We believe that the anti-arcing loop and resectoscope, designed by the senior author, achieve these goals. DESCRIPTION OF NEW ANTI-ARCING LOOP
In the new anti-arcing loop (parts B and C of figure) the spaced parallel arms of the cutting loop assembly are equally increased in length at their distal ends by such an amount
534
535
ANTI-ARCING LOOP AND RESECTOSCOPE
that in the resting or retracted positions of the cutting loop assembly the upper ends of the bare wire cutting loop are removed from the adjacent end of the telescope stem by a safe distance. Therefore, electrical arcing will not take place when current of high voltage is being used. This distance should be 2.5 or 3.0 mm. for satisfactory results. The insulation of spaced loop arms is continued to the upper ends of the dependent loop but not on the bare wire loop itself, in accordance with the conventional practice. In further accordance with the innovation the wire loop is moved from its conventional vertical position, in relation to the spaced parallel arms at 90 degrees, to a backward inclination position, which is never in contact with the telescope. This position results in the bare wire of the loop being parallel to the objective lens of the telescope. Therefore, in the new anti-arcing loop the upper end of the loop is 2.5 to 3.0 mm. distal to the telescope when the loop is at resting position and is inclined backward at approximately 30 degrees to the vertical and 60 degrees to the arms. This backward inclination of the cutting loop causes its lower part to enter first within the insulated fenestra, avoiding the incomplete cutting of pieces. The final part of each bite during resection, thus, takes place between the bottom part of the cutting loop and the inner wall of the lower part of the insulated fenestra. The backward inclination of the loop and the requirement that its lower edge engages first the inner wall of the insulated beak prevent the incomplete cutting. The loop is larger than the
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conventional loop because it forms the hypotenuse of a triangle rather than a side of the same triangle, which is the position and condition of the conventional loop and makes clean cuts easier. It is essential before the resectoscope is used to verify that the loop freely enters into the insulated fenestra at rest position. DESCRIPTION OF THE ANTI-ARCING RESECTOSCOPE
In addition to the loop innovation the resectoscope is modified to assure a guarantee against arcing. In the conventional resectoscope the telescope extends longitudinally within the instrument and is supported by an elongated metallic tube. At its proximate end it is fixed to the block of the working element and its distal end does not reach the objective lens of the telescope. In accordance with the invention shown in part B of the figure the distal end of the tube is extended beyond the distal end of the telescope sufficiently that there will be no interference with endoscopic operative vision. The tube extension is made of a material that is electrically non-conductive or a metal with a coating of electrical insulation, to prevent electrical arcing between the bare wire of the cutting loop and the telescope. REFERENCE
1. Thomas, S. D.: Eye injury during transurethral surgery. J.
Urol., 114: 584, 1975.
Vol. 119, April Printed in U .SA.
THE JOURNAL OF UROLOGY
Copyright © 1978 by The Williams & Wilkins Co.
ANTI-ARCING LOOP AND RESECTOSCOPE JOSE J. IGLESIAS, SNAPRASAD C. MADDURI, ORLANDO PETTIROSSI, ANDREW SPORER AND JOSEPH J. SEEBODE From the Department of Surgery (Urology), New Jersey Medical School, Martland Hospital and Affiliated Hospitals, the Urological Services, East Orange Veterans Administration Hospital, Newark, New Jersey, and the Instituto di Clinica Chirurgia, Trieste, Italy
ABSTRACT
A new modified cutting loop assembly and a modification of the resectoscope to prevent arcing between the bare wire loop and the distal end of the telescope are described. end of the telescope backward within the sheath but this procedure diminishes the field of endoscopic operative vision, 2) reducing the proximal movement of the cutting loop assembly in order to maintain a safe distance between the bare loop and the telescope and 3) extending the insulation of the spaced parallel arms of the loop assembly over and beyond the junction of the arms and the dependent loop but this procedure diminishes the depth of the resected pieces. These methods not only fail to prevent arcing but also reduce the efficiency of
When a transurethral operation is done with a resectoscope electrical arcing may occur between the uninsulated distal ends of the arms or the upper ends of the bare wire cutting loop and the adjacent distal end of the telescope. This arcing happens when the cutting loop assembly is moved to rest position and the end of the telescope is touched by a piece of incompletely resected tissue that has adhered to the cutting loop (part A of figure) or by the bare wire of a broken or deformed cutting loop. In the conventional loop the cutting
I
f
A, conventional loop and resectoscope. Electrical arcing may occur between uninsulated loop and telescope by piece of incompletely resected tissue that has adhered to cutting loop. B, anti-arcing loop and resectoscope. Loop arms are extended distally, bare wire loop is spaced from telescope when loop is in rest position. Telescope is protected by distal extension of tube that supports telescope. C, anti-arcing loop and resectoscope. New backward inclined position of bare wire loop. During resection this design causes bottom ofloop to enter first into insulated fenestra, initiating and assuring completely clean cut ofresected tissue with each excursion.
loop is in a vertical position and is easily deformed. The electrical arcing may damage the telescope, adversely affect the operative procedure and, possibly, cause injury to the surgeon. There have been several reports on eye injuries to surgeons doing transurethral operations, 1 and it is well known that surgeons have experienced electrical shocks and burns of the hands, cheeks, nose or ears because of arcing during an operation with the resectoscope. Among the methods suggested to correct these difficulties are 1) positioning the distal Accepted for publication June 10, 1977.
the instrument. Any modification of the resectoscope to prevent arcing should maintain the wide angle vision provided by modern optic systems and should not decrease the length of the cut at each stroke of the cutting loop. We believe that the anti-arcing loop and resectoscope, designed by the senior author, achieve these goals. DESCRIPTION OF NEW ANTI-ARCING LOOP
In the new anti-arcing loop (parts B and C of figure) the spaced parallel arms of the cutting loop assembly are equally increased in length at their distal ends by such an amount
534
535
ANTI-ARCING LOOP AND RESECTOSCOPE
that in the resting or retracted positions of the cutting loop assembly the upper ends of the bare wire cutting loop are removed from the adjacent end of the telescope stem by a safe distance. Therefore, electrical arcing will not take place when current of high voltage is being used. This distance should be 2.5 or 3.0 mm. for satisfactory results. The insulation of spaced loop arms is continued to the upper ends of the dependent loop but not on the bare wire loop itself, in accordance with the conventional practice. In further accordance with the innovation the wire loop is moved from its conventional vertical position, in relation to the spaced parallel arms at 90 degrees, to a backward inclination position, which is never in contact with the telescope. This position results in the bare wire of the loop being parallel to the objective lens of the telescope. Therefore, in the new anti-arcing loop the upper end of the loop is 2.5 to 3.0 mm. distal to the telescope when the loop is at resting position and is inclined backward at approximately 30 degrees to the vertical and 60 degrees to the arms. This backward inclination of the cutting loop causes its lower part to enter first within the insulated fenestra, avoiding the incomplete cutting of pieces. The final part of each bite during resection, thus, takes place between the bottom part of the cutting loop and the inner wall of the lower part of the insulated fenestra. The backward inclination of the loop and the requirement that its lower edge engages first the inner wall of the insulated beak prevent the incomplete cutting. The loop is larger than the
------------ ~--~-~=--~~
conventional loop because it forms the hypotenuse of a triangle rather than a side of the same triangle, which is the position and condition of the conventional loop and makes clean cuts easier. It is essential before the resectoscope is used to verify that the loop freely enters into the insulated fenestra at rest position. DESCRIPTION OF THE ANTI-ARCING RESECTOSCOPE
In addition to the loop innovation the resectoscope is modified to assure a guarantee against arcing. In the conventional resectoscope the telescope extends longitudinally within the instrument and is supported by an elongated metallic tube. At its proximate end it is fixed to the block of the working element and its distal end does not reach the objective lens of the telescope. In accordance with the invention shown in part B of the figure the distal end of the tube is extended beyond the distal end of the telescope sufficiently that there will be no interference with endoscopic operative vision. The tube extension is made of a material that is electrically non-conductive or a metal with a coating of electrical insulation, to prevent electrical arcing between the bare wire of the cutting loop and the telescope. REFERENCE
1. Thomas, S. D.: Eye injury during transurethral surgery. J.
Urol., 114: 584, 1975.