Instrument for penetrating body tissue

Abstract: An instrument (54) for the direct penetration of body tissue comprises an elongated rigid hollow shaft (56). A point (60) at the distal end of the shaft (56) is shaped to penetrate body tissue, to create an opening therein and to enlarge the opening as the point (60) is advacend into the body tissue. The distal end portion (70) of the point (60) is capable of transmitting images received back from the surgical site in advance of and laterally of the point (60). The point (60) has a cutting element (68a-68d) to enable the point (60) to pierce and cut the tissue. In the hollow shaft (56) lighting means and light image receiving means are provided.

Description: FIELD OF THE INVENTION The invention relates to an instrument for the viewing and penetration of body tissue. BACKGROUND OF THE INVENTION Instruments of this type serve particularly as trocars to create an artificial access to body cavities or organs, which do not possess any natural communicating passage with the exterior. The instrument has a point, which serves to pierce the body tissue and to widen the perforation opening and, after removal of the trocar, represents an artificial access to the body cavity, the said access through which endoscopes, instruments, and the like can be introduced into the interior of the body. The insertion of the trocar, even with the advantageous selection of an injection site, entails the risk of damaging blood vessels in subcutaneous fatty tissue, in fascia, and in the peritoneum ("abdominal membrane"), thus vessels in the abdominal wall. There is the further risk after penetration of the abdominal wall that the vessels in the abdominal area (abdominal cavity) and organs in the abdominal area, such as the large intestine, small intestine, omentum majus (greater omentum), and retroperitoneally located vessels and structures can be damaged. Especially at risk for damage are the small intestine and the omentum majus, if adhesions and concretions with the anterior abdominal wall are present, so that during penetration of the abdominal wall, structures adhering to the said wall may be pierced at the same time before the trocar enters the free abdominal cavity. To reduce the risk of damage, particularly to the intestine and omentum majus, a hollow needle can be passed through the abdominal wall first while the abdominal wall is lifted, to introduce gas into the abdominal cavity and to distance the abdominal wall from the underlying omentum majus and intestine for the subsequent insertion of the trocar. In that case as well, however, there is a residual risk of damage during the insertion of the hollow needle and the trocar. DESCRIPTION OF THE RELATED ART EP 0 484 725 A1 discloses an instrument for the penetration of body tissue which reduces as much as possible the risk of damage to vessels, organs, and the like via improved optic control during insertion. This instrument has a hollow shaft. The point or at least the distal end portion of the point is made as a window from a suitable transparent material, e.g., from glass, quartz glass, Plexiglas (registered trade mark) or the like. An optic is run through the hollow shaft to the point, e.g., an optic with glass fiber-optic light guide, as is used in endoscopes. Furthermore, a lighting unit is run in the hollow shaft to the point. The lighting unit can be integrated into the optic in that fiber-optic fibers employed for producing illumination are placed in the tract of the optic. Likewise it is possible to run the illumination separately from the optic through the shaft to the point or also to combine lighting units integrated in the optic with additional separately introduced lighting units. The optic ends at an axial distance behind the summit of the point, so that the entire surface area of the conical window can be illuminated by the optic and observed. The operator thus has a view during the advance of the instrument of the structures to be penetrated and lying in front of the instrument point. The operator can thus recognize blood vessels, for example, before these are struck by the point of the instrument, and avoid the said vessels. In particular, the important step of the penetration of the peritoneum can proceed within view. The semitransparent peritoneum almost permits a look into the abdominal cavity before total penetration, so that the underlying omentum majus, intestines, and vascular structures in the peritoneum are discernable and damage thereto can be avoided. In addition, during the advance of the instrument, the operator can observe structures penetrated by the point and passing laterally by the surface area of the window, and thus obtains a feeling for the penetration of the point and for the rate of advance. DE-A-4 133 073 discloses an instrument for the penetration of body tissue comprising a hollow shaft with a tapered distal end. The distal end is formed by planar surfaces converging into a sharp point. Within the planar surfaces of the distal end are positioned transparent windows. The surgical site in advance of and laterally of that distal end can be observed by lighting means and image receiving means introduced into the hollow shaft. Since the transparent windows are positioned in the planar surfaces behind the summit of the point, the view of the operator is restricted in front of the penetrating point of the instrument. DE-A- 2 229 239 discloses an instrument for the penetration of body tissue comprising a hollow shaft and lighting means and image receiving means inserted coaxially into the hollow shaft. The distal end of the shaft as well as of the lighting means and image receiving means is bevelled so that the penetrating point is positioned at the periphery of the hollow shaft. Therefore, the view of the operator is masked by the distal end of the hollow shaft on the site of the penetrating point. WO-A-95/13 751 comprised in the state of the art according to Art. 54 (3 EPC) discloses an instrument for the penetration of body tissue comprising a hollow shaft with a transparent point at the distal end. Lighting means and image receiving means can be introduced into the hollow shaft. The point has a pyramidal or conical shape with cutting blades in alignment with the pyramidal edges. EP-A-0 642 764 also comprised in the state of the art according to Art. 54 (3)EPC discloses an instrument for the penetration of body tissue with a hollow shaft having a transparent distal end and lighting means and image receiving means. Cutting blades are extending beyond the transparent distal end and are retractable into the distal end. SUMMARY OF THE INVENTION The invention has as its object the provision of an instrument for the penetration of body tissue under optic control which reduces the force necessary to advance the instrument during the penetration of tissue. According to the invention, the point comprises or is provided with a cutting element, especially with one or more sets of surfaces which converge to a line, i. e., a linear edge which is to incise, for example, the abdominal wall, and thereby aid in penetration. The penetration point comprises a transparent hollow cone and one or more blade members are inserted in the point, having surfaces converging to a linear edge; the linear edge is coplanar with the axis of the shaft and the conical point. These members do not extend beyond the apex of the point, in order that there may be viewed the tissue, abdominal wall, etc., adjacent and in advance of the instrument before the instrument is advanced, with the assistance of the linear edges, so that viewing of tissue, abdominal wall, etc. is made possible prior to penetration and the making of an incision in each part of the tissue or abdominal wall. Consequently, the surgeon is able to see tissue prior to engagement, penetration or cutting thereof. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in greater detail below on the basis of an embodiment presented in the figures. Shown are: Fig. 1 is an exploded perspective view of an instrument for penetration of body tissue in accordance with the present invention; Fig. 2 is an elevational view of the point shown in Fig. 1; Fig. 3 is an elevational view of an alternate embodiment of a point; Fig. 4 is an elevational view taken on the line 9-9 of Fig. 2; Fig. 5 is a view taken on the line 10-10 of Fig. 2; Fig. 6 is a cross-sectional view taken on the line 11-11 of Fig. 4, together with an optical fiber bundle; Fig 7 is an enlarged view taken on the line 12-12 of Fig. 6; Fig. 8A is an elevational view of the instrument of Fig. 1 in contact with the surface of a body; Figs. 8B and 8C illustrate successive positions in the penetration of a body with the instrument of Fig. 1 . DESCRIPTION OF THE PREFERRED EMBODIMENTS In Fig. 1 , an instrument in accordance with the invention is shown, the penetration instrument 74 comprising a linearly extending hollow rigid shaft 76 of circular configuration, and having a threaded extension 78. The point 80 is imperforate, of transparent material, and has internal threads 82 and has a cylindrical portion 84 at its proximal end of the same diameter as the shaft 76. Forwardly of the cylindrical portion 84 the point 80 preferably has a right circular conical distal end portion 86 which converges towards the distal end 90 thereof, which is preferably perpendicular to end portion 86 as shown, but could be at a different angle, with some reduction in the image acquired. Optical elements may be provided within the instrument to emit light to be passed through the window, the light being reflected from tissue, organ, etc., and passing through the windows and providing an image which is viewed by an optical viewing system. The optical viewing systems may comprise, for example, separate optical fibers, or as shown in Fig. 6, may comprise a fiber-optic bundle 72 containing both light transmitting and light receiving optical fibers; also relay lenses may be used instead of optical fibers. As shown in Fig. 2, there are provided a pair of thin blade members 88a and 88b having the bases thereof embedded in the conical distal end portion 86. The forward or distal ends of the blade members 88a and 88b terminate in a plane which passes through the truncated end 90 of the conical portion 86 of point 80. As shown in the embodiment of Fig. 3 , in the conical terminal portion 86a of point 80a, there are provided thin blade members 88c and 88d; the forward or distal ends of these members are rearwardly of the truncated end 90a of the conical portion 86a. Consequently, it will be seen that in the embodiments of Figs. 2 and 3 , the thin blade members are at or rearwardly of the distal end of the point 80, so as to enable the surgeon to see tissue or organ prior to the moving of the instrument in a manner to penetrate or cut the tissue or organ. Hence, the surgeon is enabled to view the tissue or organ in advance of the instrument prior to effecting penetration or cutting thereof. Fig. 4 and Fig. 5 are other views of the point 80, and as will be seen therein, the blade members 88a and 88b are coplanar with the axis of the point 80, and with the axis of the shaft 76. Referring now to Fig. 6 , there is shown the point 80, including the conical portion 86, with the blade elements 88a and 88b having the bases thereof embedded in the conical portion 86. The truncated end 90 of the conical portion 86 is also shown, which together with the material of the point 80 which is behind it, functions as a window lying on the axis of the point 80, for viewing of tissue or organ directly ahead of the point 80. As is apparent from Fig. 6, the blade members 88a and 88b have their forward or distal ends substantially in the plane of the truncated planar end 90. The distal end of conical portion 86 may terminate in a conical apex; blade members are at or rearwardly of it. In Fig. 7 , there is shown the truncated end 90, the conical portion 86, and the blade elements 88a and 88b; these blade elements contain converging surfaces 88e and 88f, which meet or join at a linear edge 88g, which is the cutting edge of the blade element 88a, 88b. Referring now to Figs. 8A, 8B and 8C the instrument 74 will be seen in successive stages of penetration of a tissue or organ. Initially, there will be obtained a view of the upper surface of the body to be penetrated before penetration begins. As penetration proceeds, as shown in Figs. 8B and 8C the tissue or organ is cut or severed, and the surgeon will be able to view an image of the portion of the body being penetrated, through utilization of optical lighting and viewing systems (now shown), and will be able to view tissue or organ adjoining the surface of the conical portion 86. Thus, when the instrument 74 enters into each separate layer of tissue or different element of the body, a view thereof will be obtained prior to the actual penetration or curting of that layer or element. The utilization of a penetrating point, of tapering, preferably conical configuration, together with linear edges, which cut tissue or organ, enables the instrument to penetrate tissue or organs with minimal, readily controlled force. For example, there is only required a force of about 17.8-35.6 N to advance the instrument. The claims and specification describe the invention presented, and the terms that are employed in the claims draw their meaning from the use of such terms in the specification. Some terms employed in the prior art may be broader in meaning than specifically employed herein. Whenever there is a question between the broader definition of such term as used in the prior art and the more specific use of the term herein, the more specific meaning is meant.

Claims: An instrument for the direct penetration of body tissue comprising: an elongated rigid hollow shaft (76) having a distal end; a point (80) at said distal end of said shaft (76) shaped to penetrate body tissue to create an opening therein and to enlarge the opening as the point (80) is advanced into the body tissue by said shaft (76); said hollow shaft (76) being formed to contain a lighting means and a light image receiving means; at least the distal end portion of said point (80) or a portion of said distal end portion is transparent to enable the transmission of light from said lighting means and of images received back from the surgical site in advance of and laterally of said point (80); and the point (80) having a cutting element to enable said point (80) to pierce and cut tissue; characterized in that said distal end portion is conical truncated; said cutting element is provided by at least one set of surfaces (88e, f) converging to a linear edge (88g) having one part thereof closer to the distal end portion of said point (80) than another part thereof; said surfaces (88e, f) having distal ends not beyond the planar distal end face (90) of said truncated end portion; said set of surfaces (88e, f) has at least in part surfaces of one blade member (88a, b) or at least two circumferentially spaced blade members extending outwardly from said distal end portion of said point (80) comprising said set of surfaces (88e, f) and said linear edge (88g); and said point (80) is transparent at least at said planar distal end face. The instrument of claim 1, wherein said point (80) has a central axis and said at least one linear edge (88g) is coplanar with said axis. The instrument of claim 1, wherein said blade member (88a, b) has a base portion opposite said linear edge (88g) embedded in said point (80).

Inventors: BACHMANN KARL-HEINZ, GAISELMANN THOMAS, RIEK SIEGFRIED, BACHMANN, KARL-HEINZ, GAISELMANN, THOMAS, RIEK, SIEGFRIED
Applicants: PARTOMED MEDIZINTECHNIK GMBH
Application year: 1995
Main classification: A61B17
IPC codes: A61B17, A61B19, A61B1