Vessel eversion instrument with pressurizable membrane

#The field of art to which this invention relates is medical devices, more specifically, medical devices and surgical procedures for performing anastomosis of hollow organs such as blood vessels.

#Anastomoticsurgical procedures are common in the field of cardiac surgery. These procedures are conventionally used for repairing a damaged or diseased blood vessel. In a typical anastomotic procedure, a surgeon joins a first blood vessel to a second blood vessel and creates a passageway between the two blood vessels to provide for the communication of blood flow. For this kind of anastomosis, the surgeon typically uses specialized grasping tools to manipulate a tiny, curved needle attached to an extremely fine surgical filament (e.g., under 0.001 inch diameter) to suture the vessels together. The vessels may be joined end-to-end, end-to-side, or side-to-side. To facilitate healing of the joined vessels, the prevailing standard of care requires that the surgeon suture the inside surfaces of the first and second vessels together, intima to intima. The surgeon must take great care not to damage the intima of each vessel so that endothelial cells may form over the anastomosis without the formation of thrombus or other complications, thus improving the likelihood of a long term patency of the vessels. For life-saving procedures such as coronary artery bypass graft surgery (CABG), this is especially important. When performing a distal anastomosis in a conventional CABG procedure, the surgeon typically sutures an end-to-side anastomosis of a distal end of a graft vessel (such as a segment of saphenous vein harvested from the patient) to a side of a target vessel (the stenosed coronary artery). For a proximal anastomosis in a conventional CABG procedure, the surgeon sutures a proximal end of the graft vessel to the side of the aorta.

#As this field of art has progressed over the last several years, new anastomotic methods have been developed and introduced in attempts to replace the suturing technique briefly described above. Many of these methods incorporate novel fasteners and fastener appliers. The requirement, however, to maintain intima-to-intima contact of the joined vessels remains just as important with these approaches. In fact it is often necessary, prior to joining the vessels, for the surgeon to evert (i.e., turn inside out) the end of at least one of the vessels over the end of a member such as a tube, ferrule, or bushing, etc., which is a component of the fastener or fastener applier. This exposes the intima of that vessel for presentation to the intima of the other vessel prior to fastening the vessels.

#FIG. 1 is an isometric view of an eversion instrument 10 of the present invention;

#FIG. 2 is a cross-sectional side view of the eversion instrument 10 of FIG. 1 in a depressurized mode and a sleeve 20 in a retracted position and engaging the end of a blood vessel prior to eversion;

#FIG. 3 is a partial cross-sectional side view showing eversion instrument 10 in a depressurized mode and having a sleeve 20 moved to an extended position;

#The eversion instrument 10 of the present invention is illustrated in FIGS. 1 and 2. Instrument 10 is seen to have a tubular frame 40 having a flange 46 and mounted slidably inside of a sleeve 20. A plunger 30 is seen to slidably mounted in axial bore 49 of frame 10. Mounted to the distal end 42 of tubular frame 40 is a membrane 60. These features will be described in more detail below. Eversion instrument 10 is approximately the same size and looks much like a medical syringe for administering fluids. Eversion instrument 10 is preferably single patient use, disposable, and the materials disclosed in the present embodiment are sterilizable using conventional gamma radiation, ethylene oxide, or other sterilization methods, although it is possible to construct eversion instrument 10 to be a reusable, steam autoclavable instrument, as will be apparent to those skilled in the art.

#Referring to FIG. 2, eversion instrument 10 is shown in a depressurized mode. Tubular frame 40 is seen to have a distal end 42, a proximal end 44, and an axial bore 49 therethrough. Tubular frame 40 is preferably made from a rigid or semi-rigid, conventional biocompatible material, including metals, ceramics and polymers and combinations thereof, e.g., polyethylene or polypropylene. Sleeve 20 is seen to have a distal end 22, a proximal end 24, and an axial bore 26 therethrough that fits closely over tubular frame 40 such that sleeve 20 is slidable over frame 40. An operator may grasp sleeve 20 and move it in either the proximal or distal directions over tubular frame 40, between a retracted position as shown in FIG. 2 and an extended position as shown in FIG. 3. Sleeve 20 is rigid and preferably constructed from a transparent, conventional biocompatible material such as, for example, polycarbonate in order to view the inside during operation. A plunger 30 comprises a seal 32 that fits sealably inside of axial bore 49 of proximal end 44 of tubular frame 40. The axial position of plunger 30 relative to tubular frame 40 is adjustable by pushing a pad 34 of plunger 30 close to flange 46 on tubular frame 40, or by pulling pad 34 away from flange 46. A membrane 60 made from a conventional biocompatible elastic material such as latex rubber is mounted to distal end 42 of tubular frame 40. An internal chamber 62 is formed within the enclosed space within axial bore 49 of tubular frame 40. Chamber 62 preferably contains only air, but may contain a conventional biocompatible, hydraulic fluid such as, for example, saline. When the operator pushes plunger 30 in the distal direction, the pressure inside of chamber 62 increases; when the operator pulls plunger 30 in the proximal direction, the pressure inside of chamber 62 decreases.

#Still referring to FIG. 2, a piston 56 is seen to be mounted inside the axial bore 49 at the distal end 42 of tubular frame 40. A compression spring 70 is mounted over piston 56 and between a retainer 54 on piston 56 and a stop 48 extending radially into axial bore 49 of tubular frame 40 to bias piston 56 in the distal direction. Compression spring 70 is preferably made from a stainless steel. A mandrel 50 is coaxially mounted to retainer 54 of piston 56 and comprises a rounded, distal tip 52 that engages and stretches membrane 60 into a nipple shape for insertion into the lumen of the end of a vessel 80 to be everted. Piston 56 and mandrel 50 are preferably made from a rigid plastic. Vessel 80 is held in a tubular workpiece 90, which may be a tube, ferrule, bushing, anastomotic coupler, or other device required for performing the anastomosis of vessel 80 to another vessel.