Patent Publication Number: US-2009234193-A1

Title: Apparatus for keeping clean a distal scope end of a medical viewing scope

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent application incorporates by reference U.S. patent application Ser. No. 11/542,060 filed Oct. 3, 2006. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related generally to medical equipment, and more particularly to apparatus for keeping clean a distal scope end of a medical viewing scope. 
     BACKGROUND OF THE INVENTION 
     During some conventional laparoscopic procedures, first and second trocars are used to create two openings in the patient&#39;s abdomen. A rigid laparoscope is inserted through the first trocar to visualize patient tissue. A treating medical instrument is inserted through the second trocar to treat the patient tissue being visualized with the laparoscope. Bodily fluid dispersion and floating debris have a tendency to accumulate on the scope lens of the inserted laparoscope degrading the clarity of the view. Thus, at times during the laparoscopic procedure the laparoscope must be withdrawn from the first trocar and the scope lens wiped to remove the accumulated material which caused the blurred viewing. The removal of the laparoscope is inconvenient and causes delays in the laparoscopic procedure. Upon reinsertion of the laparoscope, it is necessary for the physician to take additional time to maneuver the scope to reacquire the patient tissue of interest. 
     SUMMARY 
     A first expression of a first embodiment of the invention is for apparatus for keeping clean a distal scope end of a medical viewing scope. The apparatus includes a first tube, an annular sheath, and a handpiece. The first tube has a first proximal tube end fluidly connectable to an irrigation fluid source, has a first distal tube end, and has a substantially constant first cross-sectional flow area. The sheath is surroundingly attachable to the scope, wherein the sheath includes a tubular wall having inside and outside diameters and containing a lumen between the inside and outside diameters. The lumen has proximal and distal lumen ends, wherein the lumen has a substantially constant cross-sectional flow area which is substantially equal in area to the first cross-sectional flow area. The distal scope end is positioned proximate the distal lumen end of the attached sheath. The handpiece is mounted to the sheath, is fluidly connected to the first distal tube end, and is in fluid communication with the proximal lumen end. The handpiece is adapted to have a user-selectable first internal flow configuration preventing fluid communication between the first distal tube end and the proximal lumen end and a user-selectable second internal flow configuration allowing fluid communication between the first distal tube end and the proximal lumen end. 
     A second expression of a first embodiment of the invention is for apparatus for keeping clean a distal scope end of a medical viewing scope. The apparatus includes first and second tubes, an annular sheath, and a handpiece. The first tube has a first proximal tube end fluidly connectable to an irrigation fluid source and has a first distal tube end. The second tube has a second proximal tube end fluidly connectable to a vacuum source and has a second distal tube end. The sheath is surroundingly attachable to the scope, wherein the sheath includes a tubular wall having inside and outside diameters and containing a lumen between the inside and outside diameters. The lumen has proximal and distal lumen ends, wherein the lumen has a cross-sectional flow area which has a substantially crescent shape. The distal scope end is positioned proximate the distal lumen end of the attached sheath. The handpiece is mounted to the sheath, is fluidly connected to the first and second distal tube ends, and is in fluid communication with the proximal lumen end. The handpiece is adapted to have a user-selectable first internal flow configuration preventing fluid communication between the first distal tube end and the proximal lumen end and between the second distal tube end and the proximal lumen end, a user-selectable second internal flow configuration allowing fluid communication between the first distal tube end and the proximal lumen end but not between the second distal tube end and the proximal lumen end, and a user-selectable third internal flow configuration allowing fluid communication between the second distal tube end and the proximal lumen end but not between the first distal tube end and the proximal lumen end. 
     A third expression of a first embodiment of the invention is for apparatus for keeping clean a distal scope end of a medical viewing scope. The apparatus includes first and second tubes, an annular sheath, and a handpiece. The first tube has a first proximal tube end fluidly connectable to an irrigation fluid source, has a first distal tube end, and has a substantially constant first cross-sectional flow area. The second tube has a second proximal tube end fluidly connectable to a vacuum source and has a second distal tube end. The sheath has a central longitudinal axis, is surroundingly attachable to the scope, and is insertable into a patient. The sheath includes a tubular wall having inside and outside diameters and containing a lumen between the inside and outside diameters. The lumen has proximal and distal lumen ends, wherein the lumen has a substantially constant cross-sectional flow area which is substantially equal in area to the first cross-sectional flow area of the first tube. The sheath includes a distal sheath end portion defining a manifold. The manifold has an annular fluid passageway which has a volume and which is in fluid communication with the distal lumen end. The manifold has a plurality of spaced apart nozzle passageways which together have a total volume, which are in fluid communication with the annular fluid passageway, and which point proximal of the annular fluid passageway. The volume of the annular fluid passageway is greater than the total volume of the nozzle passageways. The distal scope end is positioned proximate the nozzle passageways of the attached sheath. The handpiece is mounted to the sheath, is fluidly connected to the first and second distal tube ends, and is in fluid communication with the proximal lumen end. The handpiece is adapted to have a user-selectable first internal flow configuration preventing fluid communication between the first distal tube end and the proximal lumen end and between the second distal tube end and the proximal lumen end, a user-selectable second internal flow configuration allowing fluid communication between the first distal tube end and the proximal lumen end but not between the second distal tube end and the proximal lumen end, and a user-selectable third internal flow configuration allowing fluid communication between the second distal tube end and the proximal lumen end but not between the first distal tube end and the proximal lumen end. 
     A first expression of a second embodiment of the invention is for apparatus for keeping clean a distal scope end of a medical viewing scope. The apparatus includes an annular sheath surroundingly attachable to the scope. The sheath includes a tubular wall having inside and outside diameters and containing a lumen between the inside and outside diameters. The lumen has proximal and distal lumen ends. The lumen substantially continuously varies in at least one of cross-sectional flow area and irrigation flow path direction. The proximal lumen end is fluidly connectable to at least one of an irrigation fluid source and a vacuum source. The distal scope end is positioned proximate the distal lumen end of the attached sheath. 
     Several benefits and advantages are obtained from one or more of the expressions of embodiments of the invention which provide for keeping clean a distal scope end of a medical viewing scope while the scope remains inserted in a patient. In one example, not removing the scope for cleaning and not reinserting the cleaned scope reduces the time for a laparoscopic procedure. In the same or a different example, not removing the scope for cleaning and not reinserting the cleaned scope keeps the inserted scope aligned with the patient tissue of interest during cleaning so that the physician does not have to take additional time to maneuver the scope to reacquire the patient tissue of interest. In one example of the first and third expressions of the first embodiment, the substantially equal areas reduce flow losses and provide faster response times for irrigation fluid to exit the lumen of the sheath to clean the distal scope end or to clean a magnifying or non-magnifying optional lens (transparent shield) of the sheath which protects the distal scope end. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a schematic top view of a first embodiment of the invention including first and second tubes, an annular sheath, a bellows shown in a fully-extended position, and a handpiece; 
         FIG. 2  is a schematic side view of the embodiment of  FIG. 1 ; 
         FIG. 3  is a schematic side view of the embodiment of  FIG. 1  together with an irrigation fluid source fluidly connected to the first tube, a vacuum source fluidly connected to the second tube, and a medical viewing scope in the form of a laparoscope having a housing and an insertion tube extending from the housing, wherein the insertion tube has been inserted into the sheath, and wherein other components of the laparoscope have been omitted for clarity; 
         FIG. 4  is a cross-sectional view of the first tube of  FIG. 1 , taken along arrows  4 - 4  of  FIG. 1 , showing the cross-sectional flow area of the first tube; 
         FIG. 5  is a cross-sectional view of the second tube of  FIG. 1 , taken along arrows  5 - 5  of  FIG. 1 , showing the cross-sectional flow area of the second tube; 
         FIG. 6  is a cross-sectional view of the sheath of  FIG. 1 , taken along arrows  6 - 6  of  FIG. 1 , showing the cross-sectional flow area of the lumen of the sheath; 
         FIG. 7A  is a cross-sectional view of the sheath and the distal end portion of the handpiece of  FIG. 2 , taken along lines  7 A- 7 A of  FIG. 2 , showing a fluid connection of the distal handpiece passageway portion with the proximal lumen end and showing the manifold defined by the distal sheath end portion, wherein the manifold has an annular fluid passageway in fluid communication with the distal lumen end and has a plurality of spaced apart nozzle passageways in fluid communication with the annular fluid passageway; 
         FIG. 7B  is a cross-sectional view of the sheath of  FIG. 7A  taken along lines  7 B- 7 B of  FIG. 7A ; 
         FIG. 8  is a view, as in  FIG. 7A , but also including the scope of  FIG. 3  showing the insertion tube of the scope inserted in the sheath; 
         FIG. 9  is a view, as in  FIG. 8 , but with the sheath inserted into a trocar which has been inserted into a patient; 
         FIG. 10  is a diagrammatic view of the handpiece and a distal portion of the first and second tubes of  FIG. 1 , showing the distal handpiece passageway portion seen in  FIG. 7A  and illustrating with flow arrows the first internal flow configuration of the handpiece; 
         FIG. 11  is a diagrammatic view, as in  FIG. 10 , but illustrating with flow arrows the second internal flow configuration of the handpiece; 
         FIG. 12  is a diagrammatic view, as in  FIG. 10 , but illustrating with flow arrows the third internal flow configuration of the handpiece; 
         FIG. 13  is a cross-sectional view of a first alternate embodiment of the sheath of  FIG. 1 , wherein the manifold is rotatable and is longitudinally extendable and retractable; 
         FIG. 14  is an enlarged cross-sectional view of the bellows, the handpiece, the sheath, and the scope of  FIG. 3 , taken along lines  14 - 14  of  FIG. 3 , showing the position of the bellows for a shorter scope; 
         FIG. 15  is a view, as in  FIG. 14 , but showing the position of the bellows for a longer scope; 
         FIG. 16  is a view of an alternate embodiment of the first tube with a fitting which has threadably received a container containing an anti-fogging liquid; 
         FIG. 17  is a cross-sectional view of the sheath and the distal end portion of the handpiece of  FIG. 7A  taken along lines  17 - 17  of  FIG. 7A  showing the lumen, wherein the lumen has a substantially straight flow path and, from  FIG. 6 , has a substantially constant cross-sectional flow area which has a substantially crescent shape; 
         FIG. 18  is a view, as in  FIG. 17 , but of a second alternate embodiment of the sheath of  FIG. 1  showing a substantially helical flow path where the lumen has a substantially constant cross-sectional flow area which has a substantially crescent shape; 
         FIG. 19  is a cross-sectional view of the sheath of  FIG. 18  taken along lines  19 - 19  of  FIG. 18  showing the substantially crescent shape of the cross-sectional flow area of the lumen of the sheath; 
         FIG. 20  is a side elevational cross-sectional view of portion of a first alternate embodiment of the handpiece of  FIG. 1  showing a first valve having a first button adapted to pump irrigation fluid into the proximal lumen end of the lumen of the sheath; 
         FIG. 21  is a side elevational cross-sectional view of a portion of a second alternate embodiment of the handpiece of  FIG. 1  showing a second valve having a second button adapted to provide suction to the lumen proximal end of the lumen of the sheath; 
         FIG. 22  is a side elevational cross-sectional view of a portion of a third alternate embodiment of the handpiece of  FIG. 1  showing a single valve having a button adapted to provide irrigation fluid into the proximal lumen end of the lumen of the sheath when partially depressed and adapted to provide suction to the lumen proximal end of the lumen of the sheath when completely depressed; 
         FIG. 23  is a view, as in  FIG. 17 , but of a third alternate embodiment of the sheath of  FIG. 1  showing a substantially helical flow path where the lumen has a substantially constant cross-sectional flow area which has a substantially circular shape; 
         FIG. 24  is a cross-sectional view of the sheath of  FIG. 23  taken along lines  24 - 24  of  FIG. 23  showing the substantially circular shape of the cross-sectional flow area of the lumen of the sheath; 
         FIG. 25  is a view, as in  FIG. 17 , but of a fourth alternate embodiment of the sheath of  FIG. 1  showing a substantially straight flow path where the lumen has a tapered cross-sectional flow area which has a substantially crescent shape; and 
         FIG. 26  is a cross-sectional view of the sheath of  FIG. 25  taken along lines  26 - 26  of  FIG. 25  showing the substantially crescent shape of the cross-sectional flow area of the lumen of the sheath. 
     
    
    
     DETAILED DESCRIPTION 
     Before explaining the several embodiments of the present invention in detail, it should be noted that each embodiment is not limited in its application or use to the details of construction and arrangement of parts and steps illustrated in the accompanying drawings and description. The illustrative embodiments of the invention may be implemented or incorporated in other embodiments, variations and modifications, and may be practiced or carried out in various ways. Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative embodiments of the present invention for the convenience of the reader and are not for the purpose of limiting the invention. 
     It is further understood that any one or more of the following-described expressions, embodiments, examples, etc. can be combined with any one or more of the other following-described expressions, embodiments, examples, etc. 
     A first embodiment of the invention is shown in  FIGS. 1-12 ,  14 - 15 , and  17 . A first expression of the first embodiment, as best seen in  FIGS. 1-3 , is for apparatus  10  for keeping clean a distal scope end  12  of a medical viewing scope  14 . The apparatus  10  includes a first tube  16 , an annular sheath  18 , and a handpiece  20 . The first tube  16  has a first proximal tube end  22  fluidly connectable to an irrigation fluid source  24  and has a first distal tube end  26 . As best seen in  FIGS. 4-9 , the first tube  16  has a substantially constant first cross-sectional flow area. The sheath  18  is surroundingly attachable to the scope  14 , wherein the sheath  18  includes a tubular wall  28  having inside and outside diameters and containing a lumen  30  between the inside and outside diameters. The lumen  30  has proximal and distal lumen ends  32  and  34 , wherein the lumen  30  has a substantially constant cross-sectional flow area which is substantially equal in area to the first cross-sectional flow area. The distal scope end  12  is disposed proximate the distal lumen end  34  of the attached sheath  18 . As best seen in  FIGS. 1-3 , the handpiece  20  is mounted to the sheath  18 , is fluidly connected to the first distal tube end  26 , and, as best seen in  FIGS. 7-9 , is in fluid communication with the proximal lumen end  32 . The handpiece  20  is adapted to have, as best seen in  FIGS. 9 and 10 , a user-selectable first internal flow configuration  1  preventing fluid communication between the first distal tube end  26  and the proximal lumen end  32 , and to have, as best seen in  FIGS. 9 and 11 , a user-selectable second internal flow configuration  2  allowing fluid communication between the first distal tube end  26  and the proximal lumen end  32 . It is noted that “fluid” includes, without limitation, gas or gasses (e.g., pressurized air) and/or liquid or liquids. 
     In one example of the first expression of the first embodiment, the fluid communication between the first distal tube end  26  and the proximal lumen end  32  includes the handpiece  20  having a distal handpiece passageway portion  4  which exits the handpiece  20  and includes the sheath  18  having a proximal sheath passageway portion  5  which enters the sheath  18 . In this example, the distal handpiece passageway portion  4  is directly fluidly connected to the proximal sheath passageway portion  5 , and the proximal sheath passageway portion  5  is directly fluidly connected to the proximal lumen end  32 . 
     It is noted that “keeping clean a distal scope end  12 ” includes cleaning at least a portion (such as a scope lens if so equipped) of the distal scope end  12  to improve scope clarity (such as scope lens clarity if so equipped), and includes cleaning at least a portion of a sheath lens (if the sheath is so equipped with a sheath lens adapted to protect the distal scope end) to improve scope clarity. It is also noted describing the first tube  16  as having a substantially constant cross-sectional flow area means the cross-sectional flow area is substantially constant from proximate the first proximal tube end  22  to proximate the first distal tube end  26 . It is further noted that describing the lumen  30  as having a substantially constant cross-sectional flow area means the cross-sectional flow area is substantially constant from proximate the handpiece  20  to proximate the distal sheath end  6 . 
     In one sheath-to-scope attachment technique, the scope  14  is slidingly insertable into the proximal sheath end portion near the handpiece  20 , the distal scope end  12  has an outside diameter, and, although not shown in the figures, the inside diameter of the tubular wall  28  near the distal sheath end  6  is less than the outside diameter of the distal scope end  12 . In one variation, the distal scope end  12  makes a press fit with the sheath  18  near the distal sheath end  6 . In one modification, the inside diameter of the tubular wall  24  has a constant taper. Other attachments, not shown, of the sheath  18  to the scope  14  include, without limitation, an elastomeric sheath, a compression fitting, and an elastomeric O-ring attached to the sheath proximate the distal sheath end  6  and adapted to attachingly engage an advancing scope  14  which has been inserted into the proximal sheath end near the handpiece  20 . 
     In one enablement of the first expression of the first embodiment, as best seen in  FIGS. 8 and 9 , the distal scope end  12  is in fluid communication with the distal lumen end  34  of the attached sheath  18 . In the same or a different enablement, as best seen in  FIG. 4 , the first cross-sectional flow area of the first tube  16  has a substantially circular shape, and, as best seen in  FIG. 6 , the cross-sectional flow area of the lumen  30  of the sheath  18  has a substantially crescent shape. In one variation, as best seen in  FIG. 9 , the scope  14  is a laparoscope, and the sheath  18  is substantially rigid and is insertable into a trocar  36 . Other types of scopes, not shown, include, without limitation, endoscopes (including gastroscopes and colonoscopes). It is noted that scopes include, without limitation, those scopes with video cameras which display an image on a monitor and those scopes having eyepieces for viewing by a physician. In one modification, as best seen in  FIG. 3 , the irrigation fluid source  24  is an operating-room saline bag  38 , and the first proximal tube end  22  is fluidly connected to the saline bag  38 . 
     A second expression of the first embodiment, as best seen in  FIGS. 1-3 , is for apparatus  10  for keeping clean a distal scope end  12  of a medical viewing scope  14 . The apparatus  10  includes first and second tubes  16  and  40 , an annular sheath  18 , and a handpiece  20 . The first tube  16  has a first proximal tube end  22  fluidly connectable to an irrigation fluid source  24  and has a first distal tube end  26 . The second tube  40  has a second proximal tube end  42  fluidly connectable to a vacuum source  44  and has a second distal tube end  46 . The sheath  18  is surroundingly attachable to the scope  14 , wherein the sheath  18  includes a tubular wall  28  having inside and outside diameters and containing a lumen  30  between the inside and outside diameters. The lumen  30  has proximal and distal lumen ends  32  and  34 , wherein the lumen  30  has a cross-sectional flow area which has a substantially crescent shape. The distal scope end  12  is disposed proximate the distal lumen end  34  of the attached sheath  18 . As best seen in  FIGS. 1-3 , the handpiece  20  is mounted to the sheath  18 , is fluidly connected to the first and second distal tube ends  26  and  46 , and, as best seen in  FIGS. 7-9 , is in fluid communication with the proximal lumen end  32 . 
     In the second expression of the first embodiment, the handpiece  20  is adapted to have, as best seen in  FIGS. 9 and 10 , a user-selectable first internal flow configuration  1  preventing fluid communication between the first distal tube end  26  and the proximal lumen end  32  and between the second distal tube end  46  and the proximal lumen end  32 , to have, as best seen in  FIGS. 9 and 11 , a user-selectable second internal flow configuration  2  allowing fluid communication between the first distal tube end  26  and the proximal lumen end  32  but not between the second distal tube end  46  and the proximal lumen end  32 , and to have, as best seen in  FIGS. 9 and 12 , a user-selectable third internal flow configuration  3  allowing fluid communication between the second distal tube end  46  and the proximal lumen end  32  but not between the first distal tube end  26  and the proximal lumen end  32 . 
     It is noted that describing the second tube  40  as having a substantially constant cross-sectional flow area means the cross-sectional flow area is substantially constant from proximate the second proximal tube end  42  to proximate the second distal tube end  46 . It is also noted that the term “vacuum” includes partial vacuum and includes aspiration. It is further noted that the term “vacuum” is relative to the pressure proximate the distal scope end  12  and that, in one example, the vacuum source may be ambient room air when the distal scope end  12  is exposed to a higher pressure within, for example, the insufflated abdomen of a patient  52 . 
     In one enablement of the second expression of the first embodiment, as best seen in  FIGS. 8 and 9 , the distal scope end  12  is in fluid communication with the distal lumen end  34  of the attached sheath  18 . In the same or a different enablement, as best seen in  FIGS. 4-6 , the first tube  16  has a substantially constant first cross-sectional flow area, the second tube  40  has a substantially constant second cross-sectional flow area which is substantially equal in area to the first cross-sectional flow area of the first tube  16 , the lumen  30  of the sheath  18  has a substantially constant cross-sectional flow area, the first and second cross-sectional flow areas each have a substantially circular shape, and the cross-sectional flow area of the lumen  30  of the sheath  18  is substantially equal in area to the first cross-sectional flow area of the first tube  16 . In one variation, as best seen in  FIG. 9 , the scope  14  is a laparoscope, and the sheath  18  is substantially rigid and is insertable into a trocar  36 . In one example, the first and second tubes  16  and  40  are each ten feet of flexible tubing. In one modification, as best seen in  FIG. 3 , the irrigation fluid source  24  is an operating-room saline bag  38 , the first proximal tube end  22  is fluidly connected to the saline bag  38 , the vacuum source  44  is an operating-room suction canister  48 , and the second proximal tube end  42  is fluidly connected to the suction canister  48 . 
     A third expression of the first embodiment, as best seen in  FIGS. 1-3 , is for apparatus  10  for keeping clean a distal scope end  12  of a medical viewing scope  14 . The apparatus  10  includes first and second tubes  16  and  40 , an annular sheath  18 , and a handpiece  20 . The first tube  16  has a first proximal tube end  22  fluidly connectable to an irrigation fluid source  24 , has a first distal tube end  26 , and has a substantially constant first cross-sectional flow area. The second tube  40  has a second proximal tube end  42  fluidly connectable to a vacuum source  44  and has a second distal tube end  46 . The sheath  18  has a central longitudinal axis  50 , is surroundingly attachable to the scope  14 , and is insertable into a patient  52 . The sheath  18  includes a tubular wall  28  having inside and outside diameters and containing a lumen  30  between the inside and outside diameters. The lumen  30  has proximal and distal lumen ends  32  and  34 , wherein the lumen  30  has a substantially constant cross-sectional flow area which is substantially equal to the first cross-sectional flow area of the first tube  16 . 
     In the third expression of the first embodiment, the sheath  18  includes, as best seen in  FIGS. 7-9 , a distal sheath end portion  54  defining a manifold  56 . The manifold  56  has an annular fluid passageway  58  which has a volume and which is in fluid communication with the distal lumen end  34 . The manifold  56  has a plurality of spaced apart nozzle passageways  60  (two are shown in  FIG. 7A  and four are shown in  FIG. 7B ) which together have a total volume, which are in fluid communication with the annular fluid passageway  58 , and which point proximal of the annular fluid passageway  58 . The volume of the annular fluid passageway  58  is greater than the total volume of the nozzle passageways  60 . The distal scope end  12  is disposed proximate the nozzle passageways  60  of the attached sheath  18 . As best seen in  FIGS. 1-3 , the handpiece  20  is mounted to the sheath  18 , is fluidly connected to the first and second distal tube ends  26  and  46 , and, as best seen in  FIGS. 7-9 , is in fluid communication with the proximal lumen end  32 . 
     In the third expression of the first embodiment, the handpiece  20  is adapted to have, as best seen in  FIGS. 9 and 10 , a user-selectable first internal flow configuration  1  preventing fluid communication between the first distal tube end  26  and the proximal lumen end  32  and between the second distal tube end  46  and the proximal lumen end  32 , to have, as best seen in  FIGS. 9 and 11 , a user-selectable second internal flow configuration  2  allowing fluid communication between the first distal tube end  26  and the proximal lumen end  32  but not between the second distal tube end  46  and the proximal lumen end  32 , and to have, as best seen in  FIGS. 9 and 12 , a user-selectable third internal flow configuration  3  allowing fluid communication between the second distal tube end  46  and the proximal lumen end  32  but not between the first distal tube end  26  and the proximal lumen end  32 . 
     In one example of the third expression of the embodiment, as best seen in  FIG. 7A , the sheath  66  includes a sheath passageway  7  consisting essentially of the proximal sheath passageway portion  5 , the lumen  30 , the annular fluid passageway  58  of the manifold  56 , and the nozzle passageways  60  of the manifold  56 . 
     In one enablement of the third expression of the first embodiment, as best seen in  FIGS. 8 and 9 , the distal scope end  12  is in fluid communication with the nozzle passageways  60 . In the same or a different enablement, as best seen in  FIGS. 4-6 , the second tube  40  has a substantially constant second cross-sectional flow area which is substantially equal in area to the first cross-sectional flow area of the first tube  16 , the first and second cross-sectional flow areas each have a substantially circular shape, and the cross-sectional flow area of the lumen  30  of the sheath  18  has a substantially crescent shape. In one example, as best seen in  FIG. 6 , the crescent shape is substantially equal in shape to an end view of substantially ninety degrees of a circularly annular right cylinder. In one variation, as best seen in  FIG. 9 , the scope  14  is a laparoscope, and the sheath  18  is substantially rigid and is insertable into a trocar  36 . In one modification, as best seen in  FIG. 3 , the irrigation fluid source  24  is an operating-room saline bag  38 , the first proximal tube end  22  is fluidly connected to the saline bag  38 , the vacuum source  44  is an operating-room suction canister  48 , and the second proximal tube end  42  is fluidly connected to the suction canister  48 . 
     In one implementation of the third expression of the first embodiment, as best seen in  FIGS. 7A and 7B , each nozzle passageway  60  has a proximal nozzle passageway end  62  and a distal nozzle passageway end  64 , and each nozzle passageway  60  is tapered from the corresponding proximal nozzle passageway end  62  to the corresponding distal nozzle passageway end  64 . In the same or a different implementation, as best seen in  FIG. 7A , the distal nozzle passageway end  64  of the attached sheath  18  has a portion abutting the distal scope end  12  and a portion spaced apart from the distal scope end  12 . In one variation, each nozzle passageway  60  is aligned to intersect the central longitudinal axis  50  of the sheath  18  at substantially the same point. 
     In a first alternate sheath embodiment, as shown in  FIG. 13 , the sheath  66  includes a mid sheath portion  68  disposed proximal to the manifold  70 , and the manifold  70  is manually rotatable about the central longitudinal axis  50  of the sheath  66  with respect to the mid sheath portion  68 . In one variation, the manifold  70  and the mid sheath portion  68  are attached by a rotatable (rotatable about the central longitudinal axis  50 ) tongue  78  and at-least-partially-annular groove  80  arrangement. In one variation, not shown, the distal scope end is angled for improved sideways viewing, the manifold is correspondingly angled, and the rotatable manifold feature allows rotational alignment of the angled manifold with the angled distal scope end. 
     In one arrangement of the third expression of the first embodiment, as best seen in  FIG. 7A , the lumen  30  has an irrigation flow path direction which is substantially parallel to the central longitudinal axis  50  of the sheath  18 . In one variation, the manifold  56  has a radiused distal inner wall portion  72  facing the distal lumen end  34 . In one example, the radiused distal inner wall portion  72  receives irrigation flow from the distal lumen end  34  and gradually turns such irrigation flow to fill the annular fluid passageway  58  of the manifold  56 , such gradual turning reducing pressure losses. 
     In one configuration of the third expression of the first embodiment, as best seen in  FIG. 8 , the sheath  18  includes a scope stop  74 , and the scope  14  is insertable into the sheath  18  and is translatable within the sheath  18  to abut the scope stop  74  to define the attached sheath  18 . In one example, the scope stop  74  is a portion of the manifold  56 . 
     In the first alternate sheath embodiment, as shown in  FIG. 13 , the sheath  66  includes a mid sheath portion  68  disposed proximal to the manifold  70 , and the manifold  70  is manually longitudinally extendable and retractable with respect to the mid sheath portion  68 . Here, the scope stop  76  is a portion of the manifold  70 . Typically, scopes  14  vary a small amount (such as one inch) in length, and the extendable and retractable manifold  70  allows scopes  14  of varying length to be fully inserted in the sheath  66  against the scope stop  76 . In one variation, the manifold  70  and the mid sheath portion  68  are attached by a sliding tongue  78  and groove  80  arrangement and have locking tabs  82  which abut during extension of the manifold  70  with respect to the mid sheath portion  68  to prevent separation of the manifold  70  from the mid sheath portion  68 . 
     In one employment of the third expression of the first embodiment having the scope stop  74 , the distal scope end  12  is the distal scope end  12  of an insertion tube  84  extending from an end of a housing  86  of the scope  14 , wherein the sheath  18  is surroundingly attachable to the insertion tube  84  of the scope  14 . In this employment, the apparatus  10  also includes, as best shown in  FIGS. 1-3  and  14 - 15 , a flexible annular bellows  88  having a central longitudinal axis  90  substantially coaxially aligned with the central longitudinal axis  50  of the sheath  18 . The bellows  88  includes a proximal bellows end  92  and includes a distal bellows end  94  which abuts the handpiece  20 . The bellows  88  is biased (such as by a spring, not shown) to extend proximally from the handpiece  20  to a fully extended position. The bellows  88  is adapted, for the attached sheath  18 , to surround the insertion tube  84  of the scope  14  with the proximal bellows end  92  contacting the end of the housing  86  of the scope  14 . This allows a shorter scope  14 ′ (see  FIG. 14 ) or a longer scope  14 ″ (see  FIG. 15 ) to be fully inserted against the scope stop  74  (see  FIG. 8 ) without a longitudinal gap between the housing  86  of the scope  14  and the handpiece  20  (see  FIG. 3 ). 
     In one illustration of the third expression of the first embodiment, the sheath  18  is manually rotatable about the central longitudinal axis  50  of the sheath  18  with respect to the handpiece  20 . In one example, the proximal sheath passageway portion  5  has a crescent shape perpendicular to the flow direction. In one variation, not shown, the distal scope end  12  is angled for improved sideways viewing, the manifold  56  is correspondingly angled, and the rotatable sheath feature allows rotational alignment of the angled manifold with the angled distal scope end. 
     In one extension of the third expression of the first embodiment, as seen in  FIG. 16 , the first tube  16  includes a fitting  96  which is disposed between the first proximal tube end  22  and the first distal tube end  26 . The fitting  96  is adapted to threadably receive a container  98  containing an anti-fogging liquid  100 . In one example, the anti-fogging liquid  100  is drawn into the flow  102  of irrigation fluid  104  by the venturi effect. 
     In one employment of the third expression of the first embodiment, as best seen in  FIG. 7A and 17 , the lumen  30  has a substantially straight proximal-to-distal flow path  106 . Flow path  106  is the flow path of the irrigation fluid in lumen  30 . It is noted that the vacuum flow path in lumen  30  is the reverse of flow path  106 . In an alternate employment, as seen in figures  18  and  19 , the lumen  108  has a substantially helical flow path  110 . Flow path  110  is the flow path of the irrigation fluid in lumen  108 . In one variation (which can be pictured as having the sheath  112  of  FIG. 18  substituted for the sheath  18  of  FIG. 7A ), this allows the distal lumen end  34  to be substantially tangentially aligned with the annular fluid passageway  58  of the manifold  56  which reduces pressure losses. 
     In one design of the third expression of the first embodiment, the first, second, and third internal flow configurations  1 ,  2  and  3  of the handpiece  20  are achieved by, as best shown in  FIGS. 10-12 , having the handpiece  20  include a first valve  114  and a second valve  116 . The first valve  114  is operatively disposed between the first distal tube end  26  and the proximal lumen end  32 , and the second valve  116  is operatively disposed between the second distal tube end  46  and the proximal lumen end  32 . The first valve  114  has a first valve button  118 , has a first fluid inlet  120  fluidly connected to the first distal tube end  26  (also seen in  FIG. 1 ), and has a first fluid outlet  122 . The second valve  116  has a second valve button  124 , has a second fluid inlet  126 , and has a second fluid outlet  128  fluidly connected to the second distal tube end  46  (also seen in  FIG. 1 ). The first fluid outlet  122  and the second fluid inlet  126  form the arms of a “Y” whose leg is the distal handpiece passageway portion  4  (seen in  FIG. 7A ).  FIG. 10  shows the first internal flow configuration  1  where the first and second buttons  118  and  124  are biased upward.  FIG. 11  shows the second internal flow configuration  2  where the first valve button  118  has been depressed.  FIG. 12  shows the third internal flow configuration  3  where the second valve button  124  has been depressed. Arrows  106  indicate the irrigation fluid flow path, and arrows  130  indicated the suction flow path. In one example, the first and second valves  114  and  116  are trumpet valves. In one variation, the saline bag  38  is disposed at a height for sufficient flow of irrigation fluid to quickly impinge the distal scope end  12  once the first valve button  118  is depressed. In one modification, a bladder, not shown, is placed around the saline bag  38  to compress the bag to increase the pressure of the irrigation fluid. 
     In an alternate embodiment of the first valve, as seen in  FIG. 20 , the first valve  132  has a first button  134  and is adapted to pump irrigation fluid into the proximal lumen end  32  (also see  FIGS. 10 and 7A ) when the first button  134  is manually depressed and when the first proximal tube end  22  is fluidly connected to the irrigation fluid source  24 . Note the one-way flapper valve  136  (in the button passageway  137  of the first button  134 ), the O-ring seals  138 , and the button return spring  140  of the first valve  132  in  FIG. 20 . The flapper valve  136  is biased open when the first button  134  is not depressed allowing irrigation fluid to flow downward below the flapper valve  136 . When the first button  134  is depressed, the flapper valve  136  is forced shut by the resisting irrigation fluid allowing a pumping action of the irrigation fluid by the downwardly-moving first button  134 . 
     In an alternate embodiment of the second valve, as seen in  FIG. 21 , the second valve  142  has a second (immovable) valve button  144  with an orifice  146 , has a one-way flapper valve  148 , and is adapted to suction air from the orifice  146  when the orifice  146  is exposed and is adapted to provide suction to the proximal lumen end  32  when the second valve button  144  is manually covered all when the second proximal tube end  42  is fluidly connected to the vacuum source  44 . The orifice  146  is disposed at the top of the second valve button  144  and is in fluid communication with a button passageway  150  of the second valve button  144 . The button passageway  150  is in fluid communication with a suction passageway  152  having a first portion  154  extending proximal of the button passageway  150  toward the second distal tube end  46  and having a second portion  156  extending distal of the button passageway  150  toward the proximal lumen end  32 . The one-way flapper valve  148  is disposed in the second portion  156  of the suction passageway  152 . When the orifice is exposed, the one-way flapper valve  148  is biased shut preventing applying suction to the proximal lumen end  32 . When the orifice is covered, the one-way flapper valve  148  is forced open, by the pressure differential, allowing suction to be applied to the proximal lumen end  32 . Note the O-ring seals  158 . 
     In an alternate embodiment which replaces the first and second valves with a single valve, as seen in  FIG. 22 , the handpiece  160  includes a single valve  162  having a single valve button  164  having first, second, and third positions, wherein the valve  162  is adapted to provide the first, second, and third internal flow configurations  1 ,  2 , and  3  based correspondingly on the first, second, and third positions of the valve button  164 . The valve button  164  has a single transverse button passageway  166 . When the valve button  164  is biased upward, the button passageway  166  is not aligned with the first fluid inlet  120  or with the second fluid outlet  128 . When the valve button  164  is partially depressed, the button passageway  166  is aligned with the first fluid inlet  120  and the first fluid outlet  122  providing fluid communication between the first fluid inlet  120  and the first fluid outlet  122 . When the valve button  164  is fully depressed, the button passageway  166  is aligned with the second fluid inlet  126  and the second fluid outlet  128  providing fluid communication between the second fluid inlet  126  and the second fluid outlet  128 . Note the O-ring seals  168 , and the button return spring  170  of the valve  162  in  FIG. 22 . 
     A second embodiment of the invention is shown in  FIGS. 1-12 ,  14 - 15 , and  17 - 19 , wherein  FIGS. 1-12 ,  14 ,  15 , and  17  illustrate the first embodiment having sheath  18 , and wherein  FIGS. 18-19  illustrate the lumen portion of a second alternate embodiment of the sheath  112  which replaces the lumen portion of sheath  18  to create the second embodiment. A first expression of the second embodiment is for apparatus  10  for keeping clean a distal scope end  12  of a medical viewing scope  14 . The apparatus  10  includes an annular sheath  112  surroundingly attachable to the scope  14 , wherein the sheath  112  includes a tubular wall  113  having inside and outside diameters and containing a lumen  108  between the inside and outside diameters, wherein the lumen  108  has proximal and distal lumen ends  32  and  34 , wherein the lumen  108  substantially continuously varies in at least one of cross-sectional flow area and irrigation flow path direction, wherein the proximal lumen end  32  is fluidly connectable to at least one of an irrigation fluid source  24  and a vacuum source  44 , and wherein the distal scope end  12  is disposed proximate the distal lumen end  34  of the attached sheath  112 . 
     In one variation of the first expression of the second embodiment, the distal scope end  12  is in fluid communication with the distal lumen end  34  of the attached sheath  112 . In the same or a different variation, the irrigation fluid flow path  110  has a substantially helical shape with a substantially constant cross-sectional flow area. In one example, the lumen  108  has a substantially crescent shape. 
     In a third alternate sheath embodiment, as shown in  FIGS. 23-24 , the lumen  172  of the sheath  174  has a flow path direction  176  (the irrigation fluid flow path direction is shown) which has a substantially helical shape. In this embodiment, the cross-sectional flow area of the lumen  172  is substantially constant and has a substantially circular shape. 
     In a fourth alternate sheath embodiment, as shown in  FIGS. 25-26 , the lumen  178  of the sheath  180  has a flow path direction  182  (the irrigation fluid flow path direction is shown) which is a substantially straight flow path direction. In this embodiment, the cross-sectional flow area of the lumen  178  has a substantially crescent shape which substantially continuously tapers from proximate the proximal lumen end  182  to proximate the distal lumen end  184 . 
     Several benefits and advantages are obtained from one or more of the expressions of embodiments of the invention which provide for keeping clean a distal scope end of a medical viewing scope while the scope remains inserted in a patient. In one example, not removing the scope for cleaning and not reinserting the cleaned scope reduces the time for a laparoscopic procedure. In the same or a different example, not removing the scope for cleaning and not reinserting the cleaned scope keeps the inserted scope aligned with the patient tissue of interest during cleaning so that the physician does not have to take additional time to maneuver the scope to reacquire the patient tissue of interest. In one example of the first and third expressions of the first embodiment, the substantially equal areas reduce flow losses and provide faster response times for irrigation fluid to exit the lumen of the sheath to clean the distal scope end or to clean a magnifying or non-magnifying optional lens (transparent shield) of the sheath which protects the distal scope end. 
     While the present invention has been illustrated by a description of several expressions, embodiments, and examples, etc. thereof, it is not the intention of the applicants to restrict or limit the spirit and scope of the appended claims to such detail. Numerous other variations, changes, and substitutions will occur to those skilled in the art without departing from the scope of the invention. For instance, the apparatus of the invention has application in robotic assisted surgery taking into account the obvious modifications of such apparatus to be compatible with such a robotic system. It will be understood that the foregoing description is provided by way of example, and that other modifications may occur to those skilled in the art without departing from the scope and spirit of the appended Claims.