Method for Rigid Tissue Biopsy

The present invention relates to apparatus used in conjunction with hypodermic needles. More particularly, the present invention relates to devices used for carrying out a biopsy.

Needles conventionally used for percutaneous biopsies of hard tissue, particularly osteomedullary tissue, consist of a cylinder of varying length and diameter with a proximal end furnished with a handle and a distal end that is more tapered than the rest of the needle and ends in a hole with a sharp edge. Through the simultaneous pushing on and rotation of the needle on its axis in the tissue being biopsied, this end cuts out a cylinder that the needle takes into its cavity. Afterward, in order to extract this biopsy cylinder from the tissue it is necessary to interrupt the continuity of the distal end with the rest of the tissue penetrated by the needle. To accomplish this with conventional methods, the needle's handle is oscillated on a plane perpendicular to the needle's axis, with a pin at the point of entry of the tissue. This maneuver results in a break in the connections between the distal end of the biopsy and the remaining tissue at the level of the needle's distal end, which can then be extracted while keeping the biopsy away from the tapered end of the needle.

This method has the following disadvantages:

a) Often the biopsy is not kept away from the needle, either because it is not completely detached from the remaining tissue or because even a very slight depression is created inside the needle during tissue extraction and the biopsy aspiration that follows it, and the piece opposite from the tapered end of the needle cannot prevent this. This makes it necessary to repeat the entire process.

b) Other times the situation described above results in the biopsy partially coming out from the distal end of the needle, leading to traumatization and breakage of the biopsy cylinder as it moves back through the tissue as well as loss of a part of the distal portion of the biopsy.

c) The oscillation or oscillations performed on the needle in order to detach the biopsy always cause minimal breakage on the surface and in the hard tissue in which the needle is fixed. The width of this breakage slowly grows as the biopsy is pulled away from the surface of the tissue, with obvious suffering on the part of the patient and with changes in the needle's structure as it tends to bend and lose the necessary linearity.

The present invention is a device used with common hypodermic needles for the execution of a biopsy. This device has a structure which is introduced through the proximal end of the needle. The structure is guided by a handle and is inserted by pressure between the internal structure of the needle and the cylindrically-shaped hard tissue removed for biopsy. The device is made of a thin plate having a curvature to fit between the internal surface of the needle and the external surface of the biopsy cylinder.

FIG. 1 is a perspective view of the apparatus prior to the removal of biopsy material.

FIG. 2 is a perspective view of the apparatus of the present invention as used in a needle during the removal of biopsy material.

This invention is a complementary apparatus for common commercial needles used for percutaneous biopsy of hard tissue, particularly osteomedullary tissue.

A simplified, non-limiting form of this apparatus is represented in the schematic drawings attached hereto as FIGS. 1 and 2. As handle-guide 1 continues to its distal end 2 in a thin plate 3, it curves to the lesser dimension according to a ray of curvature which allows introduction of it into the edge of the needle from its proximal end 4, following the internal surface of the needle 5. The plate is wide enough to cover about a third of the needle's transversal section and is longer than the longest biopsy which can be taken with that needle. The plate is introduced into the needle when the needle has already been inserted into the tissue and already contains the biopsy 6, and its distal end 7 is still continuous with the rest of the tissue 8. The thinness of the plate must be less than the space between the biopsy cylinder and the internal surface of the needle above its distal tapered end 9 but not less than the limit which guarantees rigidity during the maneuver described below. This very, thinness makes it possible for the plate to run along the needle's internal surface and insert itself between that and the tissue biopsy cylinder. When the plate is pushed forward in the needle so that it reaches the beginning of the tapered portion it is then pushed centrally towards the central axis of the needle in order to reduce the ray of curvature of the needle and it therefore touches the biopsy cylinder and meets with the cylinder's curved surface and begins to exert pressure on it. This pressure is exerted, advancing the plate further until blockage of the biopsy cylinder inside the needle against the opposite surface of the plate is guaranteed, without however altering the architecture of the biopsy tissue: rather to this it provides adequate calibration of the length of the apparatus introduced into the needle, through a reference 10 brought to the proximal end of the handle guide, in order to make it even with the proximal end of the needle 4. At this point the needle is rotated repeatedly in the same direction on its major axis, without leaving any signs of advance or retraction, nor the signs of oscillation necessary when using the traditional method mentioned in the premise. The rotation of the biopsy dragged into the needle, which is made solid by the plate, causes the complete interruption of any connection between the distal end of the biopsy 7 and the rest of the tissue 8. At this point, after having extracted the needle from the biopsied tissue, the plate will be extracted from the proximal end of the needle, and the plate will bring the biopsy cylinder with it in its concave space.