Biopsy needle set

In application of a biopsy needle set which is utilized for collecting diseased tissue sections from internal organs in a human body without requiring surgical operation, it is desirable to be certainly taken out the tissue sections by single puncture and to decrease injury of such diseased part in addition, to reduce pain in the patient at the time of sticking into the human body with the needle. In an end of suction type biopsy needle set containing double needle set of an outer needle and an inner needle, the outer needle is narrowed to form a closely contacting portion with the inner needle, whereby negative pressure can be accumulated in a cylinder at the early stage of such suction, while thus accumulated negative pressure is transferred to an opening of the outer needle at the moment when the withdrawn inner needle is passed through the above described closely contacting portion, so that such suction force sufficient for collecting the tissue sections is produced. In this case, valve function of the needle tip construction in the above biopsy needle set can realize reliability of collecting the tissue sections. Furthermore suction can be in one-handed operation by such construction that a plunger is provided with a knob projecting through the notched split formed on the cylinder.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a biopsy needle set for sucking and 
collecting tissue sections in diseased parts such as internal organs and 
the like of a patient for obtaining test specimen, and particularly to a 
biopsy needle set which can suck certainly tissue sections and maintain 
stably the suction force during removal of such needle from the human 
body. 
2. Description of the Prior Art 
As a conventional biopsy needle set, there has been proposed, for example, 
a collecting instrument of internal organ tissue sections, as shown in 
Japanese Patent Publication No. 52575/1981, which comprises, as 
illustrated in FIGS. 1 through 4, a metallic outer needle 1 an end of 
which is formed into an edge of blade and which is provided with a needle 
base 2 at the opposite end thereof, a syringe barrel 3 to an end of which 
the needle base 2 is detachably attached, an inner needle 4 an end of 
which is formed into a sharp tip portion 4a, a slidably contacting portion 
4b having a diameter a little less than a inner diameter of the outer 
needle 1 extending from said sharp tip portion 4a, and a flat supporting 
portion 4c extending further from said slidably contacting portion 4b, and 
a syringe plunger 6 on an end of which mounts a slide packing 5 fitted 
closely in the inside wall of the syringe barrel 3 to slidably move 
therein, the inner needle 4 being provided on the end of said syringe 
plunger 6. 
In the above construction, a human body is punctured with the biopsy needle 
set under such condition where the sharp tip portion 4a of the inner 
needle 4 is projected from the outer needle 1 and when the sharp tip 
portion 4a reaches an internal organ, the syringe plunger 6 and the inner 
needle 4 are relatively retracted from the syringe barrel 3 and the outer 
needle 1, so that negative pressure is produced in the syringe barrel 3 by 
withdrawal of the slide packing 5 fitted closely in the syringe barrel 3. 
Thus, such negative pressure is transmitted to the end of the outer needle 
1 through a gap defined between the outer needle 1 and the inner needle 4 
and when the syringe barrel 3 is advanced while maintaining the condition 
as mentioned above, the blade edge of the outer needle 1 cuts off the 
tissue in a columnar shape. Then, a part of the internal organ which has 
been in contact with the end of the outer needle 1 is sucked to be led 
into the outer needle 1. In this state, when the retraction of the syringe 
plunger 6 is stopped and the outer needle 1 is withdrawn from the body, 
the tissue sections being in the outer needle 1 as a result of the suction 
are torn off so that such tissue sections can be taken out from the body. 
According to the above conventional example, the slidably contacting 
portion 4b is formed at the end portion of the inner needle 4, and the gap 
is defined between the supporting portion 4c extending from the slidably 
contacting portion 4b and the inside wall of the outer needle 1, such that 
the supporting portion 4c is not in close contact with the inside wall of 
the outer needle 1 ,whereby negative pressure produced in the syringe 
barrel 3 can be efficiently transmitted to the end of the outer needle 1. 
Hence, when an internal organ to be colleted is merely punctured slightly 
with the end of the outer needle 1, a test specimen can be collected so 
that pain in a patient can be abated. In case of collecting tissue 
sections, a thick needle having a diameter of 1.05 mm (19 G) or more has 
been used as the outer needle 1 of a conventional biopsy needle. 
In accordance with such conventional collecting instrument of internal 
organ tissue sections, however, negative pressure transmitted to the end 
of the outer needle 1 keeps leaking at the slidably contacting portion 4b 
in case of suction by the syringe plunger 6, so that if it is intended to 
produce intensive suction force at the end of the outer needle 1, the 
syringe plunger 6 must be rapidly pulled. Thus there have been such 
disadvantages that the collection of test specimens becomes unreliable, 
and that in the case where outer needle 1 is made more slender for abating 
pain in a patient, only a tissue liquid except tissue sections may be 
collected because of the weak suction force. 
SUMMARY OF THE INVENTION 
It is the first object of the present invention to provide a biopsy needle 
set by which the tissue sections in a diseased part can certainly be 
collected with more intensive and continuous suction force. 
The second object of the present invention is to provide a biopsy needle 
set in which intensive suction force can be produced even in the case 
where a needle having a thin diameter is utilized for abating more pain in 
a patient. 
The third object of the present invention is to provide a biopsy needle set 
by which suction can be performed in one-handed operation. 
The forth object of the present invention is to provide a biopsy needle set 
by which tissue sections can certainly be collected even from the tissue 
containing much tissue liquid. 
The fifth object of the present invention is to provide a biopsy needle set 
wherein the rigidity thereof is not decreased even if a slender needle is 
used for easily puncturing a human body. 
According to the present invention, there is proposed a biopsy needle set 
provided with puncturing needle of a double construction composed of an 
outer needle secured to an end of a cylinder and an inner needle secured 
to an end of a plunger, and said outer needle containing slidably said 
inner needle, comprising said outer needle having the first section where 
the inside wall of said outer needle is closely in contact with said inner 
needle at the end portion of said outer needle, and the second section 
which is not in close contact with said inner needle.

DETAILED DESCRIPTION OF THE INVENTION 
The biopsy needle set according to the present invention will be described 
in detail hereinbelow by referring to the accompanying drawings. 
FIG. 5 through 8 illustrate the first embodiment of the present invention 
wherein the biopsy needle set comprises the metallic outer needle 21 which 
is composed of a close contact section A a tip portion of which is formed 
as a shape of blade, and the inner wall cross section of which may be 
tapered, a narrowed space section B at the central part thereof, and a 
reinforced section C the diameter of which is the largest and to the base 
portion of which a needle base 22 is fixed; the sharp inner needle 28 
which has a diameter to be in close contact with the outer needle 21 and a 
tip portion of which has been obliquely cut down; the cylinder 23 
containing a pair of notched splits 24 (provided with a retainer 24a for 
tentatively holding a plunger knob 31) being symmetrical with respect to 
the central axis thereof, and the rear end portion of which is covered by 
cylinder end cap 35 and to the front end portion of which the needle base 
22 is detachably attached; and the plunger 30 on the front end portion of 
which a slide packing 29 is mounted, the inner needle 28 being fixed to an 
end of the slide packing at the center thereof, and the rear end portion 
of which is provided with the knob 31. 
In the case where the inner needle 28 is inserted into the outer needle 21 
as shown in FIG. 7, air does not substantially flow in the sectiqn A since 
the outer needle is close contact with the inner needle (0.5 mm diameter). 
In the section B resistance in air flow appears at a certain degree in the 
case where air flows through an area where the outer needle is in slidable 
contact with the inner needle (outer and inner diameters of the outer 
needle being 0.8 mm (21 G) and 0.58 mm, respectively). In the section C, 
since the gap defined between the outer and inner needles is sufficient, 
resistance in air flow can be substantially neglected in the case where 
air flows therethrough (outer and inner diameters of the outer needle 
being 1.05 mm (19 G) and 0.83 mm, respectively). 
In the case when the plunger 30 provided with the knob 31 as shown in FIG. 
6 is contained in the cylinder 23, the aforesaid knob 31 is slidable along 
the notched split 24 in the body part of the cylinder 23, and the knob 31 
is tentatively held in the holding portion 24a defined at the end portion 
of the notched split 24. 
In the above construction, operations and functions of the biopsy needle 
set in the case when tissue sections are taken out by the use of the 
present biopsy needle set from internal organs in a human body will be 
described hereinbelow. 
First of all, the plunger 30 is pushed to the inside end of the cylinder 23 
by moving the knob 31 to the front end portion of the notched split 24 and 
as a result, such a situation where the tip of the inner needle 28 is 
projected from the end of the outer needle 21 with a length of about 2 mm 
is observed. The human body is punctured with the biopsy needle set while 
maintaining the above projected inner needle 28. When the needle tip 
reaches the target organ, both projections of the knob 31 are caught by 
second and third fingers of either hand of an operator, and the plunger 30 
is rapidly retracted by pulling the knob 31 until movement of the knob 31 
stops due to abutment of the knob 31 against the holding portion 24a while 
holding the lid 35 by the first finger of the same hand. As a result of 
the retracting operation of the plunger 30, it slides along the inside 
wall of the cylinder 23 being in close contact therewith so that negative 
pressure produces in a space 23a defined by the cylinder 23 and the slide 
packing 29 disposed at the end of the plunger 30 as shown in FIG. 5. Such 
negative pressure transmits to the needle tip through the interior of the 
outer needle 21, so that suction force is produced at the tip of the outer 
needle 21 because there is a pressure difference between the negative 
pressure and atmospheric pressure. 
Then, when the cylinder 23 is advanced towards the internal organ at the 
same time of the production of suction force as described above, tissue 
sections of the internal organ penetrate into the interior space of the 
outer needle 21 formed by retraction of the inner needle 28, and in 
addition the tissue sections are sucked because of the aforesaid suction 
force. After the suction, when the outer needle 21 is drawn from the body, 
the tissue sections which have been sucked in the outer needle 21 are torn 
off so that such tissue sections can be taken out from the body. 
A relationship between negative pressure (represented by pressure 
difference P from atmospheric pressure, and hereinafter referred to simply 
as "P") produced in the space 23a in the cylinder 23 during the 
above-mentioned sucking operation and stroke length (hereinafter referred 
to simply as "S") of the retracting plunger 30 with respect to the 
cylinder 23 is illustrated in FIG. 9 and the explanation therefor will be 
made hereinbelow. 
The outer needle 21 is provided with the above-mentiomed three sections in 
accordance with changes in the inner diameter thereof. In the case where 
the inner needle 28 which is in the outermost projected position from the 
outer needle 21 is rearwardly moved to pass through the section A, S to be 
required therefor is the sum of a length (l.sub.1) of such part of the 
inner needle 28 which has been projected from the outer needle 21 and the 
length (l.sub.2) of the section A. Since the outer needle 21 is in close 
contact with the inner needle 28 in this (l.sub.1 +l.sub.2) stroke, P is 
sharply increased while pressure difference P.sub.1 thus increased is 
stored. Negative pressure is transmitted to the tip of the outer needle 21 
at such moment that the tip of the inner needle 28 passes through the end 
of narrow portion 26. For this reason, intensive suction force can be 
produced at the early stage of sucking operation. The inner needle 28 is 
further retracted to enter the section B, until the plunger abuts upon the 
holding portion 24a (stroke (l.sub.3)) so that it is held tentatively. 
Even in this (l.sub.3) stroke, P increases gradually because the close 
contact in section A functions as valve means, and such increased P 
(Negative pressure) is transmitted to the needle tip so that the suction 
force is produced increasingly during the sucking operation of the stroke 
(l.sub.3). In accordance with the suction force as described above, tissue 
sections are certainly sucked during whole stage, because suction force is 
maintained for the reason why negative pressure is increasing gradually 
above pressure difference P.sub.1. 
In addition, according to the present embodiment, the plunger 30 is 
provided with the knob 31 so that suction can be made in one-handed 
operation. Thus, biopsy can easily be performed while shifting a probe of 
an ultrasonograph by another hand of the operater to observe a human body 
to be diagnosed. 
According to the construction of the biopsy needle set of the present 
embodiment, since diameter of the outer needle 21 in said section B is 
slender, i.e., 21 G (0.8 mm), pain in a patient at the time of puncturing 
the body with the needle can be reduced, whilst rigidity of the whole 
outer needle 21 can be elevated because of diameter of the outer needle 21 
of 19 G (1.05 mm) in said section C, and in addition negative pressure in 
the cylinder 23 can easily be transmitted to said section B since inner 
diameter of the outer needle 21 is 0.83 mm in said section C. 
The biopsy needle set according to the second embodiment of the present 
invention is constructed, as shown in FIG. 10, unlike the first embodiment 
in such that the plunger 30 comprises a longitudinal slot 30a of a desired 
length defined therein while a stopper 28a is formed on the rear end of 
the inner needle 28 which is slidable in the longitudinal slot 30a. 
Further there is provided another stopper 32 for anchoring the stopper 28a 
of the inner needle 28 in the case when the plunger is moved for suction 
of tissue sections as well as retraction of the needle. In this 
embodiment, when the stopper 28a of the inner needle 28 abuts upon the 
bottom of the longitudinal slot 30a, the tip of the inner needle 28 
becomes projected about 2 mm beyond the tip of the outer needle 21 as 
shown in FIG. 7. 
In accordance with the above construction, even if the plunger 30 is drawn 
back, the inner needle 28 does not retract during the stroke of the 
plunger 30 corresponding to the depth of the longitudinal slot 30a. 
Therefore, negative pressure can be stored before the inner needle begins 
to retract by the anchoring of the stopper 28a with the stopper 32. As a 
result, force for sucking tissue sections may be further enhanced. 
The biopsy needle set according to the third embodiment of the present 
invention is constructed, as shown in FIG. 11, unlike the first embodiment 
in such that the inner needle 28 has a tubular form the tip of which is 
closed, and an aperture 28b and another aperture 28c are defined in the 
front portion of the inner needle 28 and the rear portion of the inner 
needle 28, respectively. In the above construction, suction force is 
produced when the inner needle 28 pass through the close contact section A 
because negative pressure is transmitted through two passages, i.e., one 
of which is a gap defined between the outer needle 21 and the inner needle 
28, the other of which is a passage formed by communicating the aperture 
28b with the aperture 28c defined in the inner needle 28, respectively. 
Hence, even if tissue sections containing a comparatively large quantity 
of tissue liquid are sucked into the outer needle 21, decrease in suction 
force can be avoided, because there are provided two passages for 
failsafety. As a consequence, suction force can be stably maintained so 
that failure cases in collecting test specimens can remarkably be reduced. 
As described above, according to the present invention, the biopsy needle 
set is constructed in such that a closely contacting part with the inner 
needle 28 is formed on the end of the outer needle 21 while a middle part 
of the outer needle 21 having a gap for communicating negative pressure is 
made to be as small as possible in outer diameter. In such biopsy needle 
described above, therefore, negative pressure produced in the cylinder 23 
by withdrawing the plunger 30 is efficiently transmitted to the end of the 
outer needle 21 so that tissue sections can certainly be collected from a 
diseased part by intensive suction force with decreasing a pain in the 
patient.