Probe for introduction into the human or animal body, in particular a papillotome

A probe for introduction into the human or animal body, having a sheath of flexible material and a traction element extending longitudinally in the sheath that is fastened to the sheath for the purpose of effecting curvature by exerting traction at its outer end and runs on one side of the sheath in the region of curvature (B), in particular a papillotome, is to be designed so as to obtain a specified direction of curvature. For this purpose the sheath has different moments of resistance to bending in two mutually perpendicular directions across its cross-section, and the traction element is arranged on the side towards which the sheath has the smaller moment of resistance.

BACKGROUND OF THE INVENTION AND PRIOR ART 
The least complicated method for the removal of stones from the bile duct 
at present consists of the endoscopic splitting of the papilla and 
subsequent extraction of the stone. 
For this purpose a perorally introduced lateral-viewing duodenoscope is 
used, after passage through the esophagus and the stomach, to locate the 
discharge branch of the duodenum, where the bile duct and the pancreatic 
duct have a common opening in a wart-shaped protrusion (papilla). 
The opening of the papilla is first intubated with a probe pushed laterally 
out of the duodenoscope. by means of a contrast medium injected with the 
probe the two ducts are made visible radiologically, when the stones show 
up as spaces in the contrast medium. After the stones have been revealed 
in this way the probe is removed and in its place a so-called papillotome 
is introduced into the bile duct--likewise through the duodenoscope--so 
that the section of the papillotome that can be curved by means of the 
traction wire is in the region of the papilla. By traction on the traction 
wire at its outer end, whereby the papillotome is caused to curve and the 
traction wire is stretched as a chord, and by simultaneously connecting 
the traction wire to a source of current, the papilla is cut in conformity 
with the upwardly extending bile duct. The stone can then spontaneously 
emerge through the widened papilla, or be withdrawn with an instrument (a 
collecting basket). 
Because of physical conditions the chord of an arc formed by the traction 
wire after the traction always faces upward, i.e. approximately along the 
line of the duodenoscope. The direction of the cut is thus substantially 
predetermined, and in practice it is not possible, if so desired, to make 
a lateral cut without changing the position of the duodenoscope, which 
would require the duodenoscope to be re-oriented. This state of affairs is 
of considerable importance, since the cut in the papilla must always 
correspond to the course of the upwardly extending bile duct or of the 
bulge adjoining the papilla. A cut laterally across this bulge would be a 
serious complication because of perforation, with possibly fatal results. 
With this known design both the introduction of the probe described above 
and the cutting open of the papilla by means of the papillotome 
corresponding to the upward course of the bile duct are difficult, since 
the direction of curvature of the probe or of the papillotome depends 
solely on the force of traction, but is not fixed, so that substantial 
deviations can occur. 
OBJECT OF THE INVENTION 
The object of the invention is to design a probe of the above mentioned 
kind so that a specified direction of curvature can be obtained. 
BRIEF DESCRIPTION OF THE INVENTION 
In the design according to the invention the direction of curvature is 
predetermined by the direction in which the smaller resistance moment of 
the sheath acts, and is thus stabilized. This applies both to the case in 
which the smaller resistance moment acts in the same direction as that in 
which the tractive force acts and also to the case in which the direction 
of the smaller resistance moment differs from the direction of the 
tractive force. In the latter case a desired direction of curvature can be 
achieved by selecting a particular direction of the smaller resistance 
moment, which also makes it possible to adapt to the anatomical conditions 
as well as giving the desired stabilization. 
The different resistance moments in mutually perpendicular directions 
across the cross-section of the sheath can be achieved both by an 
elongated crosssection of the sheath section and by additional elements 
attached to the sheath that have the abovementioned relative resistance 
moments. For this purpose a bending element in the form of a leaf spring, 
of which the direction of bending or curvature is determined by the 
different ratios of breadth and thickness, is particularly suitable. Such 
an additional element can be attached to the sheath in a simple manner, 
e.g. by accommodating it in the space inside the sheath, by embedding it 
in the wall of the sheath or even by arranging it on the outside of the 
sheath. 
It is also an important advantage to make available to the surgeon 
performing the operation a set of assorted probes according to the 
invention in which the direction of curvature or bending predetermined by 
the design according to the invention differs from one probe to another, 
for example in 10.degree. to 15.degree. steps. In this case the doctor 
carrying out the treatment can select an appropriate probe in the light of 
his knowledge of the anatomical conditions. A particular direction of 
bending or curvature or direction of cut can thus be prescribed and 
maintained in a simple manner. 
It is also possible, within the scope of the invention, to twist the 
section of the sheath or the bending element to match the anatomical 
conditions or the desired bending or curvature, whereby it is likewise 
possible to obtain a match to predetermined or intended conditions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
The papillotome indicated generally by 1 in FIG. 1 consists of a sheath 2 
in which runs a traction element, preferably in the form of a wire 3, that 
is fixed to the papillotome 1 in the region of its introduction end, i.e. 
in the region of the inner end of the sheath 2. The sheath 2 consists of 
an elastically flexible tube, preferably of plastics material. In the 
region of the inner end indicated by 4 the sheath 2 has two holes 5, 6 on 
an axial line at a distance a from one another, the inner one, i.e. the 
hole 6 nearest to the inner end 4, is only a short distance from the inner 
end 4. The distance a amounts to about 2.5 cm. 
The wire 3 is led out through the outer hole 5 so that it runs on the 
outside of the sheath 2 and is led back in again through the inner hole 6. 
The fastening of the wire 3 to the sheath 2 is done by fastening the wire 
3 to a bending element in the form of a leaf spring 8, arranged in the 
cavity 9 of the sheath 2, to the inner end 11 of which the wire 3 is 
fixed. The length L of the leaf spring 8 is greater than the length of the 
bending section, indicated by B, in the region of which, when traction is 
exerted on the wire 3 at its outer end, the inner end 4 of the sheath 2 
takes up the curvature shown in FIG. 2, in which the wire 3 forms a chord 
12 to the arc of curvature. By means of the chord 12 it is possible in a 
known manner to make cuts in the tissue of the human or animal body after 
connecting an electric current. 
In FIG. 1 the narrow side 14 of the leaf spring 8 can be seen, i.e. it is 
turned with one of its broad sides towards the section 18 of the wire that 
runs on one side relative to the sheath 2. On exerting tractive force on 
the wire 3 at its outer end 16 the leaf spring 8 bends in the bending 
plane indicated in FIG. 3 by E.sub.1, as shown in FIG. 2. This bending 
plane E.sub.1 is at right angles to the plane E.sub.2 of the leaf spring 
8. 
Because of its narrow section, the moment of resistance to bending of the 
leaf spring 8 in the bending plane E.sub.1 is relatively small while its 
moment of resistance in its own plane E.sub.2 is relatively large. The 
leaf spring 8 thus provides guidance for the bending movement, whereby the 
bending movement is appreciably stabilized. This also applies to the 
bending back of the curved section of the sheath 2. Because of the 
presence of the leaf spring 8 it is not necessary to use an elastic 
material for the sheath 2, since this is bent back by the leaf spring 8. 
In the embodiment just described the bending direction, indicated by 17, of 
the leaf spring 8 is the same as the direction in which the bending 
section B of the sheath 2 is bent, because of the one-sided arrangement of 
the wire 3, when traction is applied to the latter. It is however 
possible, and also advantageous, for reasons that will now be described, 
to arrange the leaf spring 8 according to FIGS. 4 to 6 obliquely to the 
plane E.sub.3 which intersects the section 18 of wire that runs outside 
the sheath 2 and the central axis of the sheath 2, whereby the acute 
angles w.sub.1, w.sub.2, w.sub.3 between the plane E.sub.3 and the bending 
plane E.sub.1 of the leaf spring 8 can lie to the right or the left of the 
wire section 18. It is preferable to provide the surgeon performing the 
operation with a set of several papillotomes 1, including at least one 
papillotome according to FIGS. 1 and 3 and at least one or two 
papillotomes 1, in which the leaf spring 8 is inclined at least to one 
side of the wire section 18 (FIGS. 4 to 6). It is further advantageous to 
include in the set papillotomes 1 with angles w.sub.1, w.sub.2 of 
differing magnitudes so that the surgeon can determine the direction of 
cut as he desires so that it substantially corresponds to the direction of 
bending 17 of the leaf spring 8. The difference in angle from step to step 
preferably amounts to 10.degree. to 15.degree.. 
The modification according to FIG. 7 shows a tubular sheath 2 that is 
stabilized to in respect of its direction of bending 17 not by an 
additional bending element but because of the shape of its cross-section, 
an elongated, flattened cross-section. The direction of bending 17 is 
determined in this example by the direction in which the bending section B 
of the sheath 2 has its smaller resistance moment predetermined by the 
elongated cross-section. Here the direction of bending 17 matches the 
plane E.sub.1, i.e. the bending section B is stabilized in the plane 
E.sub.1, which is also the traction plane. 
According to FIGS. 8 and 9 an extension 21 of the leaf spring 8 extends 
beyond the outer hole 5 in the sheath 2 for stabilization of the sheath 2 
in this region. The extension 21 has a zig-zag or corrugated shape, so 
that the cross-sectional area required by the extension section 21 
corresponds to the cross-section of the cavity 9. This contributes both to 
the stabilization of the sheath 2 in this region and to a sheath 2, and 
does not interfere with the lateral emergence from a duodenoscope which 
will be described later. 
The papillotome 1 serves to widen the papilla indicated in FIG. 10 by 25 by 
means of an upwardly directed cut, so that stones (not shown) present in 
the bile duct 27 can be removed. The papillotome 1 is introduced by means 
of a lateral viewing duodenoscope 28 into the papilla 25 or into the bile 
duct 27, as described above. Tension is then applied by traction on the 
traction member that is indicated by FIG. 1 by 29 and is fastened to the 
wire 3, whereby the bending section B is curved (FIG. 2), and by 
simultaneously connecting the wire 3 to a source of current the cut 
indicated by 31 by in FIG. 11 is made. 
It can clearly be seen in FIG. 11 that the cut 31 must be made upwards and 
along the bile duct 27, since otherwise it leads to perforation of the 
bile duct, with serious consequences. 
With the design according to the invention the direction of cut, that as a 
result of the exertion of traction on the bending section B automatically 
runs substantially longitudinally of the duodenoscope 28, can be both 
stabilized and corrected by the leaf spring 8 or the particular 
cross-sectional ratio of the sheath 2. 
Because of differing anatomical conditions it is often necessary to make an 
inclined cut 31 of which the inclination differs from the line of the 
duodenoscope 28. In such cases it is advantageous to have available 
papillotomes 1 having different angles w.sub.1 to w.sub.3, in order to 
make a cut that is adapted to the anatomical proportions. In practice the 
cut 31 is begun with a conventional papillotome or a papillotome 1 
according to FIGS. 3 or 7. If the resulting direction of cut appears not 
to be optimal, which can be observed in known manner through the 
duodenoscope 28 or by means of radiology, the papillotome is exchanged for 
a papillotome with a suitable cutting angle w.sub.1 to w.sub.3 . The 
alignment of the intended cutting movement can then be made without having 
to reposition the duodenoscope 28. 
Within the scope of the invention it is possible to use other 
cross-sectional shapes of the sheath 2 and other bending elements or other 
arrangements of a bending element. It is for example possible to form the 
sheath, at least in its bending region B, from solid material. Instead of 
a leaf spring inserted in the hollow interior in the sheath 2 a leaf 
spring embedded in the material of the sheath or stuck onto the sheath can 
be used. It is also possible to form the bending region B solely from a 
leaf spring or a corresponding bending element.