Device and method for forming a hole in a tissue wall of a patient

A hole forming device for forming a hole in a vessel wall is provided. The hole forming device comprises a shaft. It further comprises a sheath arranged to be axially advanced along the shaft. It yet further comprises a distal end formation on the shaft. The distal end formation is arranged to pierce and pass through a vessel wall and to cooperate with the sheath, so that when the distal end formation has pierced and has been passed through the vessel wall, and the sheath is then advanced along the shaft, a peripheral portion of the vessel wall is drawn into the sheath and severed from the rest of the vessel wall thereby to form a hole in the vessel wall. Advantageously, the device is arranged to form the hole in a hemostatic manner. A method of forming a hole in a vessel wall is also provided.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS Referring to FIG. 1A and 1B of the drawings, a hole forming device for forming a hole in a vessel wall, in accordance with the invention, is generally indicated by reference numeral 10 . In FIG. 1 A, the device 10 is shown in a dormant condition, while in FIG. 1 B, it is shown in an actuated condition. Although the invention will be described with reference to using the device 10 to form a hole in a blood vessel wall, such as a wall of an aorta, or the like, it will be appreciated that the invention is not to be limited to forming a hole in a blood vessel wall only, but extends to forming a hole in a tissue wall of a patient body in general. The device 10 comprises a shaft 12 . The shaft 12 has a distal end formation, or portion, generally indicated by reference numeral 14 . The shaft 12 further comprises a proximal end generally indicated at 16 , as can best be seen with reference to FIG. 1E of the drawings. The distal end formation 14 has an end 14 . 1 arranged to pierce a vessel wall and to form a puncture in the vessel wall, so that the distal end formation 14 can be passed through the puncture and accordingly also through the vessel wall, as will be described in greater detail hereinbelow. The device 10 further comprises a sheath 18 mounted on the shaft 12 to be axially displaceable therealong, as indicated by arrow 20 . The sheath 18 is arranged to cooperate with the distal end formation 14 so that when the distal end formation 14 of the shaft 12 has been passed through the vessel wall, the sheath 18 can be advanced over the distal end formation 14 thereby to cause a peripheral portion of the vessel wall, adjacent the puncture formed by the distal end 14 . 1 , to be drawn into the sheath 18 and then to be severed so as to form a hole in the vessel wall, as will be described in greater detail hereinbelow. The device 10 further comprises a plunger arrangement 11 and a finger grip arrangement 13 . The finger grip arrangement 13 comprises two opposed limbs 13 . 1 , 13 . 2 . In use, the device 10 is held in a user's hand such that the plunger arrangement 11 abuts against the user's palm, while two fingers are urged against the limbs 13 . 1 , 13 . 2 . To actuate the device 10 from its dormant condition, as shown in FIG. 1 A, to its actuated condition, as shown in FIG. 1 B, the user urges his or her fingers and his or her palm together thereby to displace the plunger arrangement 11 and the finger grip arrangement 13 toward each other. The shaft 12 is typically operatively connected to the finger grip arrangement 13 and the sheath 18 is typically operatively connected to the plunger arrangement 11 . Accordingly, when the plunger arrangement 11 and the finger grip arrangement 13 are displaced toward each other in this fashion, the sheath 18 advances along the shaft 12 and over the distal end formation 14 . Conveniently, and as can best be seen with reference to FIGS. 1C and 1D of the drawings, the device 10 has a locking arrangement 15 . The locking arrangement 15 comprises a pin 17 on the shaft 12 . It further comprises a slot 19 defined in the sheath 18 . The pin 17 rides along the slot 19 when the device 10 is actuated. The slot 19 defines two opposed seats 19 . 1 , 19 . 2 . Each seat 19 . 1 , 19 . 2 defines a neck formation 19 . 3 , 19 . 4 for snap-lockingly holding the pin captive in the seats 19 . 1 , 19 . 2 . When the device is in its dormant condition, the pin 17 is held captive in the seat 19 . 1 by the neck formation 19 . 3 . When the user actuates the device 10 , as described above, by causing the plunger arrangement 11 and the finger grip arrangement 13 to displace toward each other thereby to cause the sheath 18 to advance along the shaft 12 and over the distal end formation 14 , the pin 17 is caused to ride along the slot 19 from the seat 19 . 1 and into snap-locking engagement with the seat 19 . 2 , so as to be held captive in the seat 19 . 2 by the neck formation 19 . 4 . By snap-lockingly holding the pin 17 captive in the seat 19 . 2 in this fashion, the distal end portion 14 . 1 is inhibited from inadvertently being advanced from the sheath, thereby inhibiting inadvertent injury, or damage, after a hole has been formed, as described in greater detail herein below. Although, a snap-locking arrangement has been shown, it will be appreciated that any other appropriate locking arrangement can be used instead. As can best be seen in FIG. 1E of the drawings, the end 14 . 1 is typically pointed. The distal end formation 14 comprises a rearwardly-tapering surface, or formation, 14 . 2 tapering outwardly and in an operatively rearward direction from the end 14 . 1 . At least one spiral groove 14 . 3 extends along the surface 14 . 2 from the pointed end 14 . 1 . A cutting edge, positioned proximally relative to the end 14 . 1 is indicated by reference numeral 22 . The cutting edge 22 is arranged to cooperate with the sheath 18 so as to sever a peripheral portion of a vessel wall therebetween when the sheath 18 is advanced over the cutting edge 22 . The cutting edge 22 typically defines an adjacent undercut formation 22 . 1 . Although the cutting edge 22 is shown as extending circumferentially in a straight fashion, it will be appreciated that the cutting edge can be in any appropriate form. For example, instead of extending circumferentially in a straight fashion, the cutting edge can be serrated, or the like. The distal end formation 14 further defines a gripping formation generally indicated at 24 . The gripping formation 24 is positioned proximally of the cutting edge 22 . The gripping formation 24 is arranged to cooperate with the sheath 18 so as to grip the peripheral portion of the vessel wall therebetween thereby to cause the peripheral portion to be drawn into the sheath 18 as the sheath 18 is advanced over the gripping formation 24 . The gripping formation 24 typically defines a circumferentially extending shoulder 24 . 1 on the shaft 18 . The shoulder 24 . 1 defines a circumferential edge 24 . 2 . The circumferential edge 24 . 2 has an outer diameter 26 less than an inner diameter 28 of the sheath 18 , as can best be seen in FIG. 1E . The diameter 26 of the circumferential edge 24 . 2 is typically between about 1.5 mm and about 3.5 mm less than the internal diameter 28 of the sheath, when the device 10 is arranged to form a hole in a typical blood vessel. Forming a hole in a blood vessel wall with the device 10 will now be described with reference to FIGS. 2 to 7 of the drawings, in which like reference numerals have been used to designate similar parts and features unless otherwise stated. Referring initially to FIG. 2 , the end 14 . 1 is urged against a blood vessel wall 30 of a blood vessel 32 . The shaft 12 is then caused to rotate relative to the vessel wall 30 thereby to cause the distal end formation 14 to rotate, as indicated by arrow 34 . As the shaft 12 rotates in this fashion, the pointed end 14 . 1 pierces and punctures the wall 30 to form a puncture 30 . 1 in the vessel wall 30 , as can best be understood with reference to FIG. 3 of the drawings. As the shaft 12 is rotated further, a peripheral edge 30 . 2 , of the vessel wall 30 , adjacent the puncture 30 . 1 , rides along the tapering surface 14 . 2 in the spiral groove 14 . 3 until the peripheral edge 30 . 2 drops behind the surface 14 . 2 as indicated in FIG. 3 . By causing the peripheral edge to ride along the surface 14 . 2 in the groove 14 . 3 in this fashion, the formation 14 can be passed through the vessel wall in a relatively controlled manner. Therefore, the risk of pushing the distal end formation 14 through the vessel wall too far, so that it punctures the vessel wall at an opposed side, for example, can be inhibited. Accordingly, the formation 14 can be passed through the vessel wall in a relatively safe manner. It will be appreciated that as the peripheral edge 30 . 2 of the vessel wall 30 adjacent the puncture 30 . 1 rides along the tapering surface 14 . 2 in the spiral groove 14 . 3 , the peripheral edge 30 . 2 is tensioned around the surface 14 . 2 and in the groove 14 . 3 thereby permitting hemostatic passage through the vessel wall 30 . After the vessel wall 30 has dropped behind the tapering surface 14 . 2 , the shaft 12 is urged in the direction of arrow 36 , as indicated in FIG. 3 , until the vessel wall drops behind the shoulder formation 24 , as can best be seen in FIG. 4 of the drawings. Typically, a smooth tapering surface 24 . 3 extends from behind the surface 14 . 2 to the shoulder formation 24 so that when the shaft is urged in the direction of arrow 36 , the vessel wall hemostatically rides over the surface 24 . 3 until it drops behind the shoulder formation 24 , as can best be seen with reference to FIG. 4 of the drawings. Advantageously, the shaft 12 is caused to displace angularly to and fro in a clockwise and counter clockwise direction to assist in causing the vessel wall 30 to ride along the tapering surface 24 . 3 . Referring now to FIG. 5 , when the distal end formation 14 has been inserted through the vessel wall 30 , and typically into a lumen 33 of the vessel 32 defined within the wall 30 , the device 10 is actuated, as described above, by the user urging his or her fingers and his or her palm together thereby to displace the plunger arrangement 11 and the finger grip arrangement 13 toward each other. In this fashion, the sheath 18 is advanced along the shaft 12 , as indicated by arrow 40 , until it abuts against the vessel wall 30 . As the sheath 18 is advanced further in the direction of arrow 40 , as indicated in FIG. 6 of the drawings, a peripheral portion 30 . 4 of the vessel wall 30 , immediately adjacent the edge 30 . 2 , is gripped between the gripping formation 24 and an inner surface 18 . 1 of the sheath 18 , so that when the sheath 18 is advanced further, the peripheral portion 30 . 4 is drawn into the sheath 18 . As the peripheral portion 30 . 4 is drawn into the sheath 18 in this fashion, it is typically placed in tension, or stretched, between a leading circumferential edge 18 . 2 of the sheath 18 and the gripping formation 24 . As the sheath 18 is advanced yet further, it passes over the cutting edge 22 , as can best be seen in FIG. 7 of the drawings. As it passes over the cutting edge 22 , the peripheral portion 30 . 4 is severed between the cutting edge 22 and the sheath 18 as the leading edge 18 . 2 of the sheath 18 passes over the cutting edge 22 . It will be appreciated that as the sheath 18 was advanced along the shaft 12 in this fashion, the pin 17 rode along the slot 19 from a position in the seat 19 . 1 to a position in the seat 19 . 2 . Since the pin is then held captive in the seat 19 . 2 by the neck formation 19 . 4 , the pointed end 14 . 1 is inhibited from accidentally being extended from the sheath 18 . In this fashion, inadvertent piercing or other damage to the patient is inhibited since the pointed end is retained in the sheath 18 after the hole has been formed in the vessel wall. After the peripheral portion 30 . 4 has been severed in this fashion, a hole 50 is formed in the vessel wall 30 , as can best be seen with reference to FIG. 7B of the drawings. It will be appreciated that since the peripheral portion 30 . 4 was stretched as it was drawn into the sheath 18 and before it was severed, the hole 50 has a diameter D greater than a diameter d of the cutting edge 22 . It will be appreciated that the diameter D of the hole 50 to be made in the vessel wall 30 can be varied by varying a distance L between the gripping formation 24 and the cutting edge 22 . Advantageously, the device 10 is arranged so as to form a hole having a diameter D which is greater than the diameter d of the cutting edge 22 but less than an outer diameter d 2 of the sheath 18 so that after the hole 50 has been formed, an edge 50 . 1 of the vessel 30 adjacent the hole 50 hemostatically embraces the sheath 18 , as can best be seen in FIG. 7 . With reference to FIG. 7C of the drawings, a hole formed in a vessel wall 61 with a conventional hole forming device, or punch, is generally indicated by reference numeral 63 . It has been found that when such conventional hole forming devices, or punches, are used, the hole formed is defined by an inclined circumferential edge 65 . Such a hole 63 can unnecessarily hinder blood flow in the case where the hole is formed during an anastomosis procedure. When the hole forming device in accordance with the invention is used, the circumferential edge is closer to being perpendicular relative to the wall of the vessel, as can best be seen with reference to FIG. 7 D, and as indicated by reference numeral 67 . Referring now to FIGS. 8A and 8B , a preferred distal end portion of a device 10 A in accordance with the invention, is generally indicated by reference numeral 14 A. In FIGS. 8A and 8B similar reference numerals have been used to designate similar parts, or features, unless otherwise stated. The distal end portion 14 A is similar to the portion 14 described above, but has been formed to inhibit, or at least reduce, twisting of the vessel wall 30 in response to the distal end portion 14 A being displaced angularly relative to the vessel wall 30 to pierce and pass through the vessel wall 30 . To this end, the helical groove 14 . 3 A is in the form of a smooth, relatively shallow, and gradually rounded groove, so as to inhibit, or at least reduce, friction between the portion 14 A and the vessel wall. Accordingly, the vessel wall is inhibited from being “grabbed” by the portion 14 A as the portion 14 A passes therethrough. As indicated at 15 A, the groove 14 . 3 A starts at a position operatively rearwardly of the point 14 . 1 A so as to inhibit, or at least reduce, twisting of the vessel wall 30 when the portion 14 A is used to pierce the vessel wall. Referring to FIG. 9 of the drawings, part of another hole forming device for forming a hole in a vessel wall, is generally indicated by reference numeral 110 . The device 110 is similar to the device 10 save that its tapering formation 112 has a sharp cutting edge 114 for penetrating through a vessel wall. Such an arrangement can be beneficial where the device is to be used to form a hole in a vessel wall which has a grain, such as the aorta, or the like. In such a case, the cutting edge 114 can be positioned to extend generally perpendicularly relative to the grain when piercing the aorta thereby to inhibit, or at least reduce, the risk of tearing the aorta wall. Referring to FIG. 10 of the drawings, a tapering formation of another hole forming device in accordance with the invention is generally indicated by reference numeral 120 . The tapering formation 120 has three faces 121 which extend from a pointed end 124 to a generally circular cutting edge at 126 . The pointed end 124 is arranged to penetrate a vessel wall by urging the pointed end therethrough. A tapering formation of another hole forming device in accordance with the invention is generally indicated by reference numeral 130 in FIG. 11 . The tapering formation 130 of the device shown in FIG. 11 is similar to the tapering formation 120 shown in FIG. 10 , save that it has four faces 131 which extend from its pointed end to a generally circular cutting edge at 136 . Referring now to FIGS. 12A and 12B of the drawings, a distal end formation of yet another hole forming device in accordance with the invention is generally indicated by reference numeral 140 . The distal end formation 140 comprises a tapering portion at 142 and a constant diameter portion 144 extending from the tapering portion 142 . The distal end formation 140 further comprises a helical groove 146 leading from an end 148 . Referring to FIGS. 13A and 13B of the drawings, yet another distal end formation of a hole forming device in accordance with the invention is generally indicated by reference numeral 150 . The distal end formation 150 is similar to the distal end formation shown in FIGS. 12A and 12B , save that it does not have a helically extending groove formation 146 extending along its tapering portion 154 . Accordingly, in use, the distal end formation 150 is urged through the vessel wall with or without rotation relative to the vessel wall, so that a leading end 152 pierces the vessel wall and the vessel wall rides directly up and over the tapering portion 154 . Referring to FIGS. 14A and 14B of the drawings, a distal end formation of yet another hole forming device in accordance with the invention is generally indicated by reference numeral 160 . Generally, the distal end formation 160 is used in a fashion similar to the distal end formation 150 of FIGS. 13A and 13B , save that the distal end formation 160 has a pin formation 162 arranged to pierce the vessel wall. Referring now to FIG. 15 of the drawings, a distal end formation of yet another hole forming device in accordance with the invention is generally indicated by reference numeral 170 . In use, the distal end formation 170 is inserted through a puncture, aperture, or the like, in the vessel wall, to permit the distal end formation 170 to be passed therethrough. Referring to FIG. 16 of the drawings, a distal end formation of another hole forming device in accordance with the invention is generally indicated by reference numeral 180 . The distal end formation 180 is similar to the distal end formation 14 of the device shown in FIGS. 1 - 7 , save that the distal end formation 180 has two grooves extending helically from its end 184 . The one groove, indicated by reference numeral 182 , extends in a generally clockwise direction, and the other groove, indicated by reference numeral 186 , extends in a generally counter-clockwise direction. Accordingly, in use, the distal end formation can be rotated in either a clockwise or a counter-clockwise direction so as to cause the vessel wall to ride up the distal end formation 180 in one of the grooves 182 , 186 . Instead, the distal end formation can be angularly displaced to and fro in both a clockwise and a counter-clockwise direction so as to cause the vessel wall to ride up the distal end formation 180 along portions of both of the grooves 182 , 186 . Referring now to FIG. 17 of the drawings, another hole forming device in accordance with the invention is generally indicated by reference numeral 190 . The hole forming device 190 is similar to the hole forming device 10 shown in FIGS. 1 - 7 , save that its distal end formation 194 defines a smooth tapering surface 192 leading to a pointed end 196 . In use, the formation 194 is pushed against the vessel wall to cause the leading end 196 to pierce the vessel wall to permit the distal end formation 194 to be passed directly through the vessel wall. Advantageously, the formation 194 can be displaced angularly to and fro in a clockwise and counter-clockwise direction to ease passage through the vessel wall and to reduce insertion force so as to enable the formation 194 to be passed through the vessel wall in a relatively controlled manner. In this fashion, the risk of pushing the distal end formation 194 through the vessel wall too far so that it punctures the vessel wall at an opposed side of the vessel wall, for example, can be inhibited. Referring now to FIG. 18 of the drawings, a distal end formation of yet another hole forming device in accordance with the invention is generally indicated by reference numeral 200 . The distal end formation 200 is similar to the distal end formation 14 of the device 10 shown in FIGS. 1 - 7 , save that the surface 202 extending from the cutting edge to the shoulder formation extends at a constant diameter and does not taper as in the case of the device 10 . Referring now to FIG. 19 of the drawings, yet another distal end formation of another hole forming device in accordance with the invention is generally indicated by reference numeral 210 . The distal end formation 210 comprises a tapering threaded formation for puncturing the vessel wall and for causing the vessel wall to ride screw-threadedly therealong. Referring to FIGS. 20A and 20B , a hemostatic sheath assembly is generally indicated by reference numeral 310 . The assembly 310 comprises a hemostatic sheath portion, or elongate tubular portion, 312 and a valve body 314 . The sheath portion 312 is elongate and defines a longitudinally extending passage 316 and a free end 318 defining an open mouth 320 leading into the passage 316 . The valve body 314 is mounted at an opposed end of the elongate sheath portion 312 . As can best be seen with reference to FIG. 20 B, the valve body 314 defines a seal formation 322 . The seal formation 322 is arranged sealingly to close the opposed end of the sheath portion 312 . However, the seal formation 322 is arranged to permit passage of an instrument therethrough. In use, the assembly 310 can be passed through a hole in a blood vessel, or the like, so that the free end 318 is positioned within the vessel, the vessel wall then sealingly engaging the sheath portion 312 so that the sheath portion 312 is hemostatically received by the vessel. The mouth 320 is then positioned in the vessel and the seal formation 322 inhibits blood from passing therethrough. Different instruments can then be selectively introduced into the vessel by passing the instruments through the seal formation, the seal formation inhibiting the escape of blood from the vessel when the instruments are selectively passed into the vessel through the seal formation. In accordance with another aspect of the invention, a method of forming a hole in a vessel wall will now be described with reference to FIGS. 21 and 22 . In FIGS. 21 and 22 , the same reference numerals as used herein above, have been used to designate similar parts or features unless otherwise stated. Referring initially to FIG. 21 , the hole forming device 10 shown in FIGS. 1 to 7 above, is shown in a condition in which its sheath 18 has been positioned to extend internally along the hemostatic sheath portion 312 of the hemostatic sheath assembly 310 shown in FIGS. 20A and 20B . Accordingly, the hemostatic sheath assembly 310 is positioned such that it extends along the sheath 18 of the device 10 . The sheath 18 extends co-axially within and along the passage 316 and through the seal formation 322 , not shown in FIGS. 21 and 22 , of the hemostatic sheath assembly 310 . The seal formation 322 sealingly embraces the sheath 18 . As shown in FIG. 21 , after the hemostatic sheath assembly has been so positioned on the sheath 18 of the device 10 , the device 10 is used to form a hole 348 in a wall 350 of a vessel 352 in a fashion similar to that described above with reference to FIGS. 2 to 7 of the drawings. After the hole 348 has been formed by the device 10 , the device 10 is urged carefully in an operatively forward direction to cause the end 18 . 2 of the sheath 18 to pass through the hole 348 . After the end 18 . 2 has been urged through the hole 348 in this fashion, an edge 354 of the vessel wall 350 defining the hole 348 hemostatically seals against an end portion of the sheath 18 at the end 18 . 2 . Accordingly, by using the device 10 the hole 348 is formed under hemostatic conditions. After the hole 348 has been formed by the device 10 , and as can best be seen with reference to FIG. 22 of the drawings, the hemostatic sheath assembly 310 is advanced along the sheath 18 of the device 10 such that the end 320 passes through the hole 348 between the sheath 18 and the edge 354 of the vessel wall 350 defining the hole 348 . Advantageously, an end portion 312 . 1 of the hemostatic sheath portion 312 is tapered in an operatively rearward direction to assist in passing the end 320 of the hemostatic sheath portion 312 through the hole 348 and to ease the edge 354 of the wall 350 radially outwardly. After the end 320 has been passed through the hole 348 in this fashion, the edge 354 of the wall 350 hemostatically embraces the hemostatic sheath portion 312 . After the hemostatic sheath assembly 310 has been so positioned to extend through the hole 348 , the device 10 can be removed from the hemostatic sheath assembly 310 by withdrawing the device 10 through the seal formation 322 . In this way the hemostatic sheath assembly 310 can be operatively positioned to extend through a hole in a blood vessel, or aorta, or the like, under hemostatic conditions. After the device 10 has been removed from the hemostatic sheath assembly 310 , the assembly 310 can be left in place relative to the vessel 352 to serve as a port through which instruments can be passed to access the vessel 352 . Although a method of forming a hole in a vessel wall is described above with reference to FIGS. 21 and 22 using the device 10 of the invention, it will be appreciated that any other appropriate hole forming device can be used instead of the device 10 . For example, any one of the hole forming devices described above with reference to FIGS. 8 to 19 can be used instead. Furthermore, any other appropriate hole forming device, or punch, could be used in the method as described with reference to FIGS. 21 and 22 . For example, a conventional hole forming device, or punch, can be used, such that the method can then comprise forming an initial incision in the vessel wall, passing the conventional hole forming device through the incision while it extends through a hemostatic sheath assembly, and then advancing the hemostatic sheath assembly relative to the hole forming device so as to pass through the hole in the vessel wall in a manner similar to that described above with reference to FIGS. 21 and 22 . When such a conventional hole forming device is used in this fashion, the method can include clamping the blood vessel for a short period so as to inhibit blood from escaping from the vessel from when the incision is made to when the hemostatic sheath assembly has been hemostatically positioned relative to the blood vessel. Although certain embodiments of the invention have been described above in detail for purposes of clarity and understanding, it will be appreciated that the invention has been described with reference to the above embodiments by way of example only, and that modifications or changes can be made without detracting from the essence of the invention. Accordingly, the scope of the invention is to be defined by the appended claims with due regard to equivalents of the claimed elements or features.