Method for selective endoscopic cannulation of ductal structures

A method and device for selective endoscopic cannulation is disclosed. The cannulator includes an elongated intermediate portion which is normally straight and flexible and a distal tip portion which flexibly deviates in a specific direction away therefrom. The cannulator also includes a referential coupling, maintained in fixed relation within the cannulator, which allows bending of the cannulator along a portion of the length of the cannulator in a first plane which is transverse to the longitudinal axis of the referential coupling while resisting bending in other transverse planes relative thereto. The cannulator is advanceable through the operating channel of an endoscope and through the entrance into the ductal system, where it can be positioned with the referential coupling located at the entrance to the ductal system. When so located, the referential coupling maintains a predictable orientation between the cannulator and the ductal entrance in dependence upon the position of the operating end of the endoscope relative to the ductal entrance. By manipulating the endoscope and cannulator relative the ductal entrance, with the referential coupling maintaining the predicted relative orientation between the cannulator and the entrance in response to these manipulations, the tip of the cannulator can thus be predictably maneuvered within the ductal system to thereby locate and cannulate the desired ductal structure therein.

BACKGROUND OF THE INVENTION 
Cannulae used in endoscopic retrograde cholangiopancreatography (ERCP) 
allow access to the bile or pancreatic ducts through the sphincter of Oddi 
which opens into the duodenum at the papilla of Vater. When performing an 
ERCP procedure, difficulty is sometimes encountered in the attempt to 
successfully cannulate the desired duct within this ductal system. This 
difficulty can result in a prolongation of the procedure or possibly 
inadequate diagnosis and/or therapy, which can possibly cause severe and 
sometimes life-threatening consequences. 
Previous devices designed to facilitate selective access of the segments 
within the biliary tree have included steerable catheters, bowed 
papillotomes, and curved tip wire guides. None of these devices have 
satisfactorily provided precise control of the cannula tip and therefore 
have proven inadequate for selective cannulation. Fully steerable cannulas 
have not enjoyed wide acceptance because they are too bulky for practical 
operation through the biopsy channel of a pancreaticobiliary endoscope. 
Thinner steerable devices, which are capable of steering in only one or 
two directions, offer little advantages over a standard catheter. 
Bowed papillotomes are sometimes used like a standard catheter to gain 
access to specific structures within the biliary ductal system. When used 
in this manner, however, the cutting wire of the bowed papillotome 
interferes with the cannulation process, while the only advantage over a 
standard catheter that is provided is additional flexion for redirecting 
the tip in only one direction. As a result, bowed papillotomes are awkward 
to use and fail to provide improved effectiveness. 
Commonly used to gain access to many structures within the body, wire 
guides are also commonly used to effect cannulation of ducts within the 
biliary ductal system. Guide wires, however, carry the risk of blunt 
trauma to structured segments of the bile or pancreatic ducts which can 
result in life-threatening infection, perforation or pancreatitis. Given 
the present alternatives, there is a need and usefulness for a new 
approach which extends the utility of endoscopic cannulas that are used to 
secure selective intraluminal access to hollow tubular structures, such as 
are found in the pancreaticobiliary tree. 
SUMMARY OF THE INVENTION 
The present invention provides for precisely directed endoscopic 
cannulation for the purpose of selective access within the 
pancreaticobiliary ductal system. In addition to providing precise 
directional control for selectively accessing specific segments of the 
pancreaticobiliary tree, the present invention may be useful to gain 
cannulation within other ductal systems as well. 
The method of cannulation described and claimed involves introducing a 
specially constructed selective cannulator through an endoscope and into a 
patient. The selective endoscopic cannulator defines a cannulating lumen 
and includes an elongated intermediate portion, which is normally straight 
and flexible and which defines a longitudinal axis, and a distal tip 
portion which flexibly deviates in a specific direction away from the 
longitudinal axis defined by said intermediate portion. The cannulator 
also includes a referential coupling, maintained in fixed relation within 
the cannulator, which allows bending of the cannulator along a portion of 
the length of the cannulator in a first plane which is transverse to the 
longitudinal axis of the referentiai coupling while resisting bending in 
other transverse planes relative thereto. 
The cannulator is advanced through the operating channel of the endoscope 
and through the entrance into the ductal system, where it is positioned 
such that the referential coupling is located at the entrance to the 
ductal system, wherein the referential coupling, by allowing bending in a 
specific transverse plane relative thereto at the ductal entrance while 
resisting bending in other transverse planes, maintains a predictable 
orientation between the cannulator and the ductal entrance in dependence 
upon the position of the operating end of the endoscope relative to the 
ductal entrance. By manipulating the endoscope and cannulator relative the 
ductal entrance, with the referential coupling maintaining the predicted 
relative orientation between the cannulator and the entrance in response 
to these manipulations, the tip of the cannulator can thus be predictably 
maneuvered within the ductal system to thereby locate and cannulate the 
desired ductal structure. 
A specially constructed cannulator device for selectively cannulating 
ductal structures within a ductal system for use with the method of the 
present invention is also described and claimed herein. In the illustrated 
embodiment, the selective endoscopic cannulator includes a multi-lumen 
tubular catheter, and has an elongated intermediate portion which is 
normally straight and flexible and which defines a longitudinal axis, and 
a distal tip portion which flexibly deviates in a specific direction away 
from the longitudinal axis defined by said intermediate portion. One inner 
lumen, which provides cannulated access to the distal tip of the 
cannulator, is circular in cross-section and is sized to receive a wire 
guide therein with sufficient spacing to allow contrast medium to be 
injected therethrough with the wire guide positioned within the lumen. The 
second inner lumen is rectangular in cross-section and contains a flat 
wire of nickel titanium alloy, which acts as a referential coupling by 
maintaining a predictable relative orientation between the cannulator and 
the entrance to the ductal system in dependence upon the relative 
direction of angled entry of the cannulator into the ductal system. The 
proximal and distal end of the rectangular lumen are sealed. Implanted in 
the rectangular lumen at the distal tip of the cannula is a platinum coil 
which is highly visible on fluoroscopy. 
In one illustrated embodiment of the selective cannulator of the present 
invention. The distal tip portion is oriented in a 2 o'clock position 
relative to the longitudinal axis of the intermediate straight portion of 
the cannulator. So configured, the cannulator has been found to be 
particularly suited for cannulation of the left hepatic duct and segments 
of the pancreatic duct. In a second illustrated embodiment, the distal tip 
portion is oriented in a 10 o'clock position relative to the longitudinal 
axis of the intermediate straight portion of the cannulator. This 10 
o'clock configuration is particularly suited for cannulating the cystic 
duct and gall bladder, and the right hepatic duct. 
According to one important aspect of the present invention, there is 
provided a selective cannulator with a referential coupling that maintains 
a predictable orientation between the cannulator with respect to the 
entrance to a ductal system in dependence upon the relative direction of 
angled entry whereby, as the cannulator is manipulated within the ductal 
system, a predictable orientation is maintained for the tip of the cannula 
within the ductal system being probed. By this means, precise directional 
cannulation of almost any ductal structure can be simply accomplished. 
This invention extends the utility of endoscopic cannulas which are used to 
secure selective intraluminal access to hollow tubular structures, such as 
are found in the pancreaticobiliary tree, and can be used to gain 
selective access to structures within other ductal systems as well. Within 
the pancreaticobiliary tree alone, the present invention facilitates 
selective cannulation of: 1) the cystic duct and gallbladder; 2) the left 
hepatic duct and the intrahepatic ducts thereafter; 3) the right hepatic 
duct and the intrahepatic ducts thereafter; 4) segments within the 
pancreatic duct; or 5) abscesses or pseudocysts contained in the pancreas 
and pancreatic duct.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
For the purposes of promoting an understanding of the principles of the 
invention, reference will now be made to the embodiment illustrated in the 
drawings and specific language will be used to describe the same. It will 
nevertheless be understood that no limitation of the scope of the 
invention is thereby intended, such alterations and further modifications 
in the illustrated device, and such further applications of the principles 
of the invention as illustrated therein being contemplated as would 
normally occur to one skilled in the art to which the invention relates. 
Referring now to the drawings, FIGS. 1 a-c are views of a "2 o'clock" 
cannulator 2 for selective endoscopic cannulation according to the present 
invention. FIG. 1 a is a segmented side elevational view of cannulator 2, 
showing the location of a flat wire 4 of nitinol material within 
cannulator 2. Owing to its superelastic properties and its reliably 
reproducible flexion, nitinol is considered to be particularly suited for 
use in flat wire 4. Spring steel may adequately serve as an alternative 
material, particularly for devices which are designed for one time use. 
FIG. 1 a also shows platinum coil 5 in the distal tip portion 9 of 
cannulator 2. Platinum is known to be an exceptionally radio-dense metal, 
and thereby provides for precise fluoroscopic localization of cannulator 2 
within the body during the cannulation procedure. 
Cannulator 2 has an intermediate portion 1 which is straight and flexible 
and which therefore normally defines a longitudinal axis, and a distal end 
portion 9 which is molded to flexibly deviate therefrom in a 2 o'clock 
direction relative thereto (where 12 o'clock is the normally medial 
direction relative to an endoscope as cannulator 2 exits therefrom, which 
orientation is reliably repeatable each time cannulator 2 is advanced 
through an endoscope owing to the bending of flat wire 4 at the curvature 
portion of the operating channel at the operating end of the endoscope). 
The shaft cannulator 2 is made of extruded transluscent Teflon material 
which has been heat molded into the deviating curvature at distal tip 
portion 9, as shown. At its distal end, cannulator 2 is tapered to a 
reduced diameter as well to facilitate insertion into and dilation of 
smaller ductal structures. Also shown in FIG. 1a, at the proximal end of 
cannulator 2, is a standard Luer-Lock adapter 6 which provides access into 
cannulator 2 for the wire guide insertion, injection of contrast medium, 
and aspiration. 
FIG. 1b is a top plan view of the "2 o'clock" cannulator of FIG. 1 a. FIG. 
1c is a sectioned view of the 2 o'clock cannulator of FIGS. 1 a-b, 
sectioned along lines A--A in FIG. 1a, and illustrates the relative 2 
o'clock orientation of the distal tip portion 9 of cannulator 2, and shows 
a first cannulating lumen 3, which is circular in cross-section, and flat 
wire 4, which is maintained in fixed relation within cannulator 2 inside a 
second, rectangularly shaped lumen. 
Similarly, FIGS. 2a-c are views of a "10 o'clock" cannulator 10 for 
selective endoscopic cannulation according to the present invention. FIG. 
2a is a segmented top plan view of cannulator 10, showing the location of 
flat wire 14 of nitinol material within cannulator 10, and also showing 
platinum coil 15 located within the distal tip portion 19 of cannulator 
10. Intermediate portion 11 is straight and flexible and normally defines 
a longitudinal axis, from which distal end portion 19 is molded to 
flexibly deviate in a 10 o'clock direction relative thereto. Also shown in 
FIG. 2a, at the proximal end of cannulator 2, is a standard Luer-Lock 
adapter 16. 
FIG. 2b is a side elevational view of the "10 o'clock" cannulator of FIG. 
2a. FIG. 2c is a sectioned view of the "10 o'clock" cannulator of FIGS. 
2a-b, sectioned along lines B--B in FIG. 2a, and illustrating the relative 
10 o'clock orientation of the distal tip 19 of cannulator 10, and the 
internal orientation of cannulating lumen 13 and flat wire 14 within 
cannulator 10. 
FIGS. 3a-b are enlarged views, respectively, of the distal end of 
intermediate portion 1 and the distal tip portion 9 of the "2 o'clock" 
cannulator 2 shown in FIGS. 1 a-b. FIGS. 3a-b illustrate the relative 
orientation of cannulating lumen 3, nitinol flat wire 4, and platinum coil 
5 within cannulator 2. In FIGS. 3a-b, it is seen that flat wire 4 extends 
within distal tip portion 9. Maintained within its constricting 
rectangular lumen within cannulator 2, flat wire 4 is twisted to conform 
to the deviating curvature of distal tip portion 9. In this relative 
configuration, with flat wire 4 extending within distal tip portion 9, the 
directional flexion of distal tip portion is further assured relative to 
the longitudinal axis of intermediate portion 1. Alternatively, flat wire 
4 may be positioned to only extend within intermediate portion 1. In this 
relative configuration, the directional flexion of distal tip portion 9 is 
due solely to the molded shape of the Teflon (or other suitable) material 
which forms the shaft of the distal tip portion 9. Also, flat wire 4 may 
be sized to extend only along only a portion of the distal end of 
intermediate portion 1 of cannulator 2, or may be constructed to extend 
the entire length thereof. A suitable length is in the range of 30-60 cm. 
at the distal end which is adequate for positioning within both the 
curvature in the operating channel of the endoscope and the ductal 
entrance. Longer lengths, while not adding to overall operability, may 
adequately function for the purpose intended. 
FIGS. 4a is a further enlarged cross-sectional view of cannulator 2 of 
FIGS. 1 a-b, cross-sectioned along lines A--A. FIG. 4b is an illustration 
of the cross-sectional view of FIG. 4a with wire guide 88 positioned 
within cannulating lumen 3 of cannulator 2, with sufficient spacing to 
allow contrast medium to be injected therethrough while wire guide 88 is 
so positioned. 
An illustrative example of the method of selective cannulation of the 
present invention utilizing the above described instrumentation will now 
be described. First, an endoscope is introduced into the patient and 
positioned with its operating end in proximity with the Sphincter of Oddi. 
A wire guide is then advanced through the operating channel of the 
endoscope and through the ductal entrance to gain access into the ductal 
system. A selective endoscopic cannulator, as described above, is then 
advanced over the wire guide, through the operating channel of the 
endoscope, and through the entrance into the ductal system. 
The cannulator is then positioned with its referential coupling (flat wire) 
located at the Sphincter of Oddi, so that, by allowing bending in a 
specific transverse plane relative thereto at the Sphincter of Oddi while 
resisting bending in other transverse planes, the referential coupling 
maintains a predictable orientation between the cannulator and the ductal 
entrance in dependence upon the position of the operating end of the 
endoscope relative to the ductal entrance. By manipulating the endoscope 
and cannulator relative the ductal entrance with the referential coupling 
located at the entrance thereto to predictably maneuver the tip of the 
cannulator within the ductal system, the desired ductal structure can 
thereby be easily located and cannulated. 
FIGS. 5a-c illustrate the above described technique for manipulating the 
tip of a selective cannulator 2 of the present invention within a ductal 
system by maneuvering endoscope 77 about the entrance 99 (Sphincter of 
Oddi) to the ductal system (pancreatobiliary tree) while flat wire 4 acts 
as a referential coupling between cannulator 2 and entrance 99. In FIG. 
5a, 2 o'clock cannulator 2 is shown advanced through the operating channel 
78 of endoscope 77 and through the Sphincter of Oddi 99 into the biliary 
duct, with referential coupling 4 positioned within both the Sphincter of 
Oddi 99 and the curvature of the operating channel 78 at the end of 
endoscope 77. In this position, and with endoscope 77 in a 12 o 'clock 
orientation with respect to the Sphincter of Oddi 99, the distal end 
portion 9 of cannulator 2 assumes its natural 2 o'clock orientation. 
FIGS. 5b-c illustrate the precise maneuverability of cannulator 2 within 
the pancreatobiliary tree that is obtainable by manipulating endoscope 77 
about the Sphincter of Oddi 99. In FIG. 5b, endoscope 77 has been moved in 
a counterclockwise direction CC about ductal entrance 99, and the relative 
corresponding counterclockwise movement of the distal tip portion 9 of 
cannulator 2 within the ductal system is shown, owing to the referential 
coupling effect between cannulator 2 and ductal entrance 99 that has been 
formed by flat wire 4. In this figure, it is seen that, by allowing 
bending in only one direction, flat wire 4 causes distal tip portion 9 of 
cannulator 2 to rotate relative to ductal entrance 99 as endoscope 77 is 
moved thereabout. 
In FIG. 5c, the effect of the opposite movement, in a clockwise direction 
C, of endoscope 77 about ductal entrance 99, and the relative 
corresponding clockwise movement of distal tip portion 9 of cannulator 2 
within a ductal system is shown. Owing to the referential coupling effect 
between of flat wire 4 and ductal entrance 99, referential coupling 4 
causes distal tip portion 9 of cannulator 2 to correspondingly rotate 
relative to ductal entrance 99 in a clockwise direction in response to the 
clockwise movement of endoscope 77 about ductal entrance 99. 
It is to be noted that FIGS. 5a-c show referential coupling 4 positioned 
within both the curvature of the operational channel 78 of endoscope 77 
and ductal entrance 99 during the manipulation procedure. By so 
maintaining a referential coupling between cannulator 2 and both endoscope 
77 and ductal entrance 99, a higher degree of precision in the relative 
movement of cannulator 2 may be obtained at the sacrifice of an overall 
loss of a degree of freedom of movement. 
By appropriately selecting a selective cannulator of the present invention 
with the desired orientation of its distal tip portion, any of a wide 
variety of ductal structures can be easily and simply cannulated. For 
example, the 2 o'clock cannulator, as above described, is particularly 
suited for cannulation of the left hepatic duct and segments of the 
pancreatic duct. The orientation of the second illustrated embodiment, the 
10 o'clock cannulator, is particularly suited for cannulating the cystic 
duct and gall bladder, and the right hepatic duct. 
While the invention has been illustrated and described in detail in the 
drawings and foregoing description, the same is to be considered as 
illustrative and not restrictive in character, it being understood that 
only the preferred embodiment has been shown and described and that all 
changes and modifications that come within the spirit of the invention are 
desired to be protected.