US 20080108878 A1
An improved tissue engagement device such as a suction stabilizer or retractor. The stabilizer or retractor is provided with one or more suction pods mounted to the distal end of a flexible arm. The flexible arm is coupled to a base assembly, which attaches the arm to an associated retractor or other structure that is fixedly located relative to the operative site. The base assembly includes a fixed portion, which is coupled to the retractor or other fixed mounting point and a rotatable turret, allowing rotation of the arm relative to the fixed portion of the base assembly. A tensioning mechanism mounted to the turret applies tension to compress the turret around a corresponding pivot mounted to the fixed portion of the base to rotationally lock the turret and to lock the arm in its current configuration. If the device is a suction stabilizer, it may carry a spreading/tightening mechanism along with two suction pods and the tensioning mechanism may lock the relative location of the spreading/tightening mechanism relative to the arm and operate to spread the suction pods apart from one another to provide for additional stabilization at the desired anastomosis site. If the device is a suction retractor, the tensioning mechanism may lock a pivotably mounted carrier for a single enlarged suction pod so that the suction pod is held in its desired orientation relative to the arm.
1. A tissue engaging device, comprising:
an elongated arm, flexible to display multiple configurations, having a proximal end and a distal end and a longitudinal axis;
a tissue engagement mechanism, mounted to the distal end of the arm;
a base assembly comprising a fixed base member and a rotatable base member mounted to the proximal end of the arm, rotatable to provide rotation of the axis of the arm at its proximal end relative to the fixed base member;
a tension member extending through the rotatable base member and arm; and
a tensioning mechanism mounted to the rotatable base member, operably coupled to apply tension to the tension member to concurrently rotationally lock the rotatable base member to the fixed base member and lock the flexible arm in its then current configuration.
This patent application is a continuation of U.S. patent application Ser. No. 11/003,100, filed Dec. 3, 2004, which is a continuation of U.S. patent application Ser. No. 10/122,971, filed Apr. 11, 2002, which are both incorporated by reference in their entirety.
The present invention generally relates to surgery on body tissues and organs. More specifically, the present invention relates to methods and devices for engaging an organ, e.g. for positioning an organ in a desired orientation or for temporarily immobilizing a local area of tissue subject to motion, such as the heart wall, which permits a surgical procedure to be performed on that local area of tissue.
Coronary artery disease remains the leading cause of morbidity and mortality in Western societies. A number of approaches have been developed for treating coronary artery disease. In less severe cases, it is often sufficient to merely treat the symptoms with pharmaceuticals or to treat the underlying causes of the disease with lifestyle modification. In more severe cases, the coronary blockage can be treated endovascularly using techniques such as balloon angioplasty, atherectomy, laser ablation, stents, and the like. In cases where these approaches have failed or are likely to fail, it is often necessary to perform a coronary artery bypass graft procedure.
The coronary artery bypass graft procedure traditionally required a heart-lung or cardiopulmonary bypass. Due to the risks incurred during cardiopulmonary bypass, beating heart bypass surgery techniques have been developed to allow coronary artery bypass without cardiopulmonary bypass. Several systems are presently available which attempt to immobilize epicardial tissue in the immediate vicinity of an anastomosis site through a pressure stabilizer employing a simple mechanical fork. Such a device stabilizes the heart by pressing a fork downwards onto the heart surface. The fork is typically mounted to an elongated arm, which in turn is typically mounted to a retractor, holding the patient's ribs apart to create an operative window. Angular movement of the arm relative to the retractor in some cases is accomplished by means of a turret, which may be clamped in its desired rotational position. Longitudinal movement of the arm relative to the retractor is typically allowed as well, and clamping mechanisms are typically provided to allow clamping of the arm to the turret and locking of the fork relative to the arm. Exemplary pressure stabilization devices are disclosed in U.S. Pat. No. 6,876,332, issued to Looney and U.S. Pat. No. 6,036,641, issued to Taylor, et al., both incorporated herein by reference in their entireties. Suction stabilization systems, such as the Medtronic Octopus® Tissue Stabilizer (available from Medtronic, Inc., Minneapolis, Minn. USA), instead employ a comparatively long, flexible, articulating arm carrying a pair of suction paddles or pods at its distal end. During use, the arm is typically secured to a retractor, holding the patient's ribs apart to create an operative window. The pods are placed on either side of the anastomosis site and suction is applied to grip and immobilize the surface of the heart. Thereafter, tension is applied along the length of the arm to lock the arm in its position and to lock the position of the pods relative to the Arm. In Medtronic's device, is generally disclosed in pending U.S. patent application Ser. No. 09/396,047, filed by Boone, et al. on Sep. 15, 1999, for a “Method And Apparatus For Temporarily Immobilizing A Local Area Of Tissue”, incorporated herein by reference in its entirety. In this device, a single knob, mounted to the proximal end of the arm, is employed to lock the arm in position and additionally to spread the pods somewhat, slightly stretching the heart's surface to provide additional stabilization of the heart surface. In such devices, all adjustment of the arm relative to the retractor is accomplished by varying the configuration of the flexible arm, prior to locking it in its desired position. Other examples of suction stabilization devices are disclosed in U.S. Pat. No. 6,113,534, issued to Koros, et al., U.S. Pat. No. 6,007,486, issued to Hunt, et al, U.S. Pat. No. 5,836,311, issued to Borst, et al. and U.S. Pat. No. 5,727,569, issued to Benetti, et al., all incorporated herein by reference in their entireties.
In conjunction with stabilization devices, suction retractors are often employed to position the heart to allow access to the desired anastomosis site. The Medtronic Starfish™ device and the Guidant Axius™ Expose™ device are examples of commercially available suction retractors. These devices employ a single, larger suction pod to engage the heart, typically in the vicinity of the heart apex. The suction pod is carried by a flexible arm, which, like the suction stabilizers discussed above, also may be locked into a desired configuration by tension applied along their length. The application of tension to the arm may also serve to lock a carrier for the suction pod relative to the arm to fix the suction pod in a desired orientation relative to the arm, as in the Guidant device. The Medtronic device is described in pending U.S. patent application Ser. No. 09/679,294, filed Jun. 12, 2001 by Keogh, et al. for a “Method and System for Organ Positioning and Stabilization, incorporated herein by reference in its entirety. The Guidant device is described in the brochure” Axius™ Expose™ Device, Instructions for Use, Guidant Corp., 2001, P/N 30462, Rev. A, also incorporated herein by reference in its entirety. Other suction retractors are described in U.S. Pat. No. 6,019,772, issued to Spence, et al. and PCT Publication No. WO 01/17437 by Peng, both also incorporated herein by reference in their entireties.
The present invention provides an improved tissue engagement device such as a suction stabilizer or retractor, which includes features intended to allow for easier use of the device and to simplify the operations necessary to lock the device in a desired configuration. In a preferred embodiment, the invention takes the form of a suction stabilizer having suction pods mounted to the distal end of a flexible arm. In this embodiment, the flexible arm is coupled to a base assembly, which attaches the arm to an associated retractor or other structure that is fixedly located relative to the operative site. The base assembly includes a fixed portion, which is coupled to the retractor or other fixed mounting point and a rotatable portion, for example, comprising a turret, allowing rotation of the arm and turret relative to the fixed portion of the base assembly. In the embodiment disclosed, the flexible arm is locked into a desired position by means of a tensioning mechanism, also mounted to the turret. The invention may also be embodied as a suction retractor, having a similar flexible arm, wherein the tensioning mechanism similarly locks the turret and the arm.
In the preferred embodiment of the present invention described in detail herein, the tensioning mechanism mounted to the turret applies tension to a cable extending through the flexible arm, to the distal end of the arm, which carries a spreading/tightening mechanism along with two suction pods. The tensioning mechanism applies tension along the entire length of the arm to compress the turret around a corresponding pivot, mounted to the fixed portion of the base, to lock the arm in its current configuration, to lock the relative location of the spreading/tightening mechanism relative to the arm and to spread the suction pods apart from one another to provide for additional stabilization at the desired anastomosis site. If the invention is embodied as a suction retractor, the tensioning mechanism would correspondingly lock the turret and arm in the same fashion, and optionally could lock a pivotably mounted carrier for the single enlarged suction pod so that the suction pod is held in its desired orientation relative to the arm.
In preferred embodiments of the invention, all operations of the tensioning mechanism are controlled by rotation of a single knob or other control mechanism, simplifying use of the device. In the disclosed embodiment of the invention, the suction pods are interconnected by means of a conduit located distal to the spreading/tightening mechanism, allowing for the use of a single vacuum line to provide vacuum to suction pods while retaining an over-all low profile to the spreading/tightening mechanism. In the disclosed embodiment of the invention, an improved clamping mechanism is also provided for locking the fixed portion of the base assembly to an associated retractor. The improved clamping mechanism employs a cam pin which is used both to move a sliding lock component upward to clamp it against the fixed portion of the base and to move the sliding lock component laterally to tighten the sliding lock component against the retractor or other fixed mounting point for the assembly.
While the various aspects of the invention are most preferably embodied in a suction stabilizer or retractor with an articulating arm, certain aspects of the invention may be useful in the context of a pressure stabilizer and/or a stabilizer with a rigid arm and/or a suction retractor with a rigid arm. In addition, it is anticipated that the invention will be applicable to similar surgical devises intended for use in other medical procedures, as they may be developed.
The foregoing and other aspects of the present invention will best be appreciated with reference to the detailed description of a preferred embodiment of the invention in conjunction with the accompanying drawings, wherein:
The preferred embodiment shown in
Turning now to
Pivot mount 240 carries the turret pivot 242, which takes the form of a disk topping a cylindrical section extending upward and at an angle from the pivot mount 240. First and second turret halves 206 and 216, when assembled, are mounted around the turret pivot 242, allowing the turret and attached flexible arm to pivot relative to the fixed portion of the base assembly. The first and second turret halves 202 and 216 are provided with grooved portions 207, 217, adapted to engage with the disk-shaped top portion of turret pivot 242, allowing rotation but preventing removal of the first and second turret members 206 and 216. Turret halves 206 and 216 are connected to one another by means of hinge pin 208. When assembled, hinge pin 208 passes through bore 212 in the second turret half 216, through bore 210 in the first turret half 206 and then is anchored in bore 214 of the second turret half 216. By this arrangement, turret halves 206 and 216 may pivot relative to one another. The dimensions of the internally formed grooves in turret halves 206 and 216 are such that when the two components are pivoted around pin 208 such that their lower extremities are in close proximity to one another, they correspondingly clamp inwardly around the turret pivot 242, locking the turret rotationally into position relative to the fixed portion of the base assembly. When assembled, projection 215 is located in a corresponding recess in turret half 206, maintaining the turret halves in alignment.
The mechanism for tensioning cable 40 (
Operation of the tensioning mechanism is as follows. The distal extremity of the threaded member 220 is provided with a hexagonally shaped distal portion 220, which is located in a corresponding hexagonally configured recess 218 in the proximal portion of the second turret half 216. Threaded member 222 is free to slide within this recess, but cannot rotate. When assembled, washers 226 are located within the proximal end of the first turret half 216, and provide a bearing surface against which handle 23 rotates. Handle 23 is provided with internal threading corresponding to the external threading on member 222. Rotation of handle 23 thus causes proximal movement of member 222 against sleeve 228, in turn causing proximal movement of the cable 40, correspondingly tightening the components of the articulating arm and the turret, to affix them in their desired positions. Resilient tabs 223 of handle 23 cooperate with corresponding notches formed in the second turret half 216 to prevent over-rotation of the handle 23 and consequent detachment of the handle. This aspect of the operation of the tensioning mechanism is discussed in more detail below in conjunction with
As discussed below, proximal movement of cable 40 also serves to stabilize the location of the spreading mechanism 21 at the distal portion of the arm (as illustrated in
Mounted to the fixed portion of the base assembly is sliding clamp 26. Clamp 26 is provided with inwardly directed tabs 234 and is also provided with two upwardly extending projections 236. When assembled, projections 236 are located adjacent the distal ends of springs 244, which lie in downwardly extending grooves formed in the lower surface of pivot mount 240 and urge clamp 26 distally. Handle 200 and cam rod 202 also make up a portion of the clamping mechanism, passing through bore 248 in the clamp 26. Functional operation of the clamp 232 is described in more detail in conjunction with
In this view, turret halves 206 and 216 are shown mounted to one another by means of hinge pin 208, and the inter-relation of the internal circumferential grooves 207, 217 in turret halves 206 and 216 can be appreciated. These grooves are shown as located closely adjacent to the outer surface of the pivot 242. Movement of the lower portions of the turret halves 206 and 216 toward one another due to tension provided by the cable 40 tightly clamps the turret to the turret pivot 242. Handle 23 is shown with its threaded inner surface engaging the threaded member 222 and its distal surface lying adjacent washers 226, located in a recess formed in the proximal end of turret component 216. The hexagonally shaped distal portion of threaded member 222 is shown lying within a correspondingly configured lumen 264 formed within turret half 216, allowing for longitudinal movement of threaded member 220 but not rotational movement. Sleeve 226 is shown located within the handle 26, adjacent the proximal end of threaded member 220 and is mounted to the proximal end of the tension cable 40
More clearly visible in this view is the mechanism by which clamp 26 operates in conjunction with the pivot mount 240 to provide a mechanism for attaching the assembly to an associated chest retractor. Pivot mount 240 is provided with a downwardly extending projection having a proximally facing angled surface 252, corresponding to a distally facing angled surface 254 on the distal end of clamp 26. In use, a portion of a retractor is located between these two slanted surfaces, and clamp 26 is moved distally as far as possible so that that portion of the retractor is held between pivot mount 240 and clamp 26. Cam pin 256 is located within an angled bore 260 formed in clamp 26, having its lower extremity located proximal to its upper extremity. Pin 256 extends through and is located slidably within a downwardly extending slot 262, formed in pivot mount 240. Although not shown in this view, the enlarged head portion 258 of pin 256 bears downwardly along the upper surface 238 of the pivot mount 240. Cam rod 202 has its camming surface located within a cross bore in the pin 256, configured so that rotation of the handle 200 and associated cam rod 202 pulls the pin downward relative to the pivot mount 240 and is correspondingly pulls clamp 26 upward into tight contact with pivot mount 240. Because pin 256 and bore 260 are angled less than 90 degrees relative to the axis along which the clamp 26 slides, rotation of the cam rod 202 by means of lever 200 (
Suction pods 22 correspond generally to those described in conjunction with the '047 application, cited above. However, rather than delivering vacuum individually to each pod, only a single vacuum line is required, coupled to vacuum connector 25. Distribution of vacuum to both pods is accomplished by means of a cross bore 320, molded into the plastic component 310 which forms the body of suction pods 22.
Malleable metal tubes 304 and 306 are shown located within longitudinally aligned bores within components 309 and 310. Tube 304 extends to the vacuum connector 305, and serves as the vacuum source for both pods 22. The proximal end of tube 306 is capped by ball 308, and the recess adjacent to it is backfilled, for example with silicone rubber. The distal ends of both tubes 304 and 306 are similarly capped with balls 307 and backfilled. Cross bore 320 extends all the way through the molded plastic component 309. However, it is sealed at its ends by means of the tubular projections 340 and 342 of component 309. After assembly, the slight recesses 322 and 324 may be filled with silicone rubber. Malleable tubes 304 and 306 are formed such that each is provided with a laterally directed opening 328, 326 which as assembled aligns with the cross bore 320, providing a mechanism for communicating vacuum applied to tube 304 to tube 306, and thereby evenly applied to both suction pods 22. Vacuum applied to tube 304 is delivered to cup shaped recesses in each of the pods, indicated at 316 and 318, by means of bores 312 and 314, in a fashion similar to that as employed in the presently available Medtronic devices.
In the embodiments illustrated above, the stabilizer is disclosed as a stabilizer having a flexible, articulating arm. As noted above, the invention may similarly be practiced in a suction retractor with an articulating arm. Moreover, certain aspects of the invention might also be used fully practiced in the context of a stabilizer or retractor with a rigid arm. For example, the ability to simultaneously rotationally lock the turret relative to the fixed portion of the base assembly in conjunction with adjustment of the angular position of the spreading/tightening assembly relative to the arm or adjustment of the position of the suction pod of a retractor relative to the arm would still be desirable. Similarly, in the context of a suction stabilizer with a rigid arm, the ability to simultaneously lock the turret rotationally relative to the fixed portion of the base and spread the pods 22 would still be valuable. The various features discussed above in conjunction with the lock, the spreading/tightening mechanism could also usefully be employed in a stabilizer with a rigid arm. Similarly, while the disclosed embodiments of the invention take the form of a suction stabilizer, inclusion of the ability to simultaneously adjust the position of the turret relative to the fixed portion of the base and adjust the position of the tissue contact members in a pressure stabilization device would also be of use in a pressure stabilizer.
While the disclosed embodiment employs a knob and a threaded shaft to apply tension to the cable, causing the locking of the turret to the fixed portion of the base assembly, alternative mechanisms for applying tension to the cable could of course be substituted. For example, the tensioning mechanisms disclosed in U.S. Pat. No. 6,007,486 issued to Hunt, et al., U.S. Pat. No. 5,899,425 issued to Corey, et al. and U.S. Pat. No. 6,264,605 issued to Sirica, et al. could all usefully be substituted for the tensioning mechanism of the present invention, while remaining within the scope of the present invention. As such, the above description and associated drawings should be considered as exemplary, rather than limiting, with regard to the scope of the claims which follow: