Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
1999-04-28
2001-04-10
Buiz, Michael (Department: 3731)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
C606S108000, C606S194000
Reexamination Certificate
active
06214022
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates principally to a perfusion device for use in performing minimally-invasive vascular microsurgeries and in particular to minimally invasive coronary artery bypass grafting (CABG) procedures such as an internal mammary artery (IMA) or vein graft to a coronary artery anastomosis procedure. The device of the invention maintains blood flow distally in a coronary artery such as the LAD during the construction of an anastomosis, thereby preventing ischemia and maintaining a dry anastomosis site to facilitate the procedure.
Surgeons are constantly striving to develop advanced surgical techniques resulting in turn in the need for developing advanced surgical devices and instruments to facilitate performance of such techniques. Recent advances in the surgical field are increasingly related to operative techniques which are less invasive and reduce overall patient trauma. To illustrate, in the field of CABG procedures it has been common practice for surgeons to perform a sternotomy where a lengthy incision is made down the middle of the chest to expose the body cavity in the thorax region, wherein retractors are employed to provide the surgeons the access required to perform the necessary bypass surgery.
However, more recent surgical techniques employ less invasive CABG procedures, known as “endoscopic” surgery, involving the use of an endoscope instrument which permits the visual inspection and magnification of any cavity in the body, such as the thorax cavity. The procedure involves the insertion of tubes called trocar cannulas through the soft tissue protecting the body cavity. The surgeon then performs diagnostic and therapeutic procedures at the surgical site with the aid of specialized micro-instrumentation designed to fit through the various trocar cannulas that provide the required openings into the body cavity.
In such endoscopic techniques, an arterial blood source such as an IMA is dissected from its location, transacted and prepared for attachment at an anastomosis site on a selected coronary artery, commonly the left anterior descending artery (LAD). To this end, a portion of the LAD is exposed and an incision is made in the arterial wall. The distal end of the IMA is then sutured over the incision in the LAD to complete the bypass graft surgery.
However, in order to perform the above surgical procedures, heart activity must be arrested. Thus, to maintain the patient, it is necessary first to divert the patient's blood circulation through an extracorporeal cardiopulmonary bypass system. This is accomplished by isolating the heart at selected arterial locations using selected catheter instruments and occluders to draw the blood into the bypass system for oxygenation thereof via an associated pump oxygenator. The oxygenated blood is returned to the patient to maintain the patient's systemic circulation during the surgery. The procedure further includes the ligating of vessels by pinching off the vessel with sutures and/or the use of occluder devices in the artery, the functions of which are to prevent the flow of blood through the artery to maintain a dry surgical site during the suturing of the anastomosis.
Accordingly, many typical cardiovascular surgical procedures, even many so-called less invasive procedures, include the procedures of placing the patient on a cardiopulmonary bypass system and then inducing cardioplegia arrest of the heart. It follows that the entire anastomosis construction is performed with the heart in the arrested state, and with special precautions taken to prevent any blood flow in the vessel on which the anastomosis surgery is being performed. To this end, an occluder device, which is sometimes inserted in the blood vessel to isolate the anastomosis site, is specifically configured to be impenetrable to the flow of fluid and to thereby prevent the flow of blood through the occluder device at the anastomosis site.
The surgical procedures of previous mention experience the disadvantages of increased trauma to the arteries caused by ligatures, to the heart due to the cessation of blood flow to distal portions thereof, and to the patient in general due to the cardiopulmonary bypass and cardioplegia arrest procedures and instruments. Accordingly, it would be highly desirable when performing a bypass surgery to circumvent the problems of previous mention, that is, to obviate the need for a cardiopulmonary bypass procedure and to allow the anastomosis construction to be performed without the occlusion of blood flow through the associated blood vessel and to prevent ischemia while still maintaining a dry anastomosis site to facilitate the suturing procedure.
An analogous problem is encountered whenever a surgical procedure penetrates the wall of a vessel. In many instances, the problem is overcome using mechanical means to occlude the vessel, either by externally clamping the vessel closed, or by use of an intravascular occluder as mentioned above. However, both approaches necessarily interrupt blood flow through the vessel, depriving the downstream tissue of oxygenated blood and creating the possibility of ischemia/reperfusion injury.
SUMMARY AND DESCRIPTION OF THE INVENTION
The present invention overcomes the above problems by enabling a surgeon to perform an anastomosis construction on, for example, a left anterior descending coronary artery (LAD) without occluding the distal flow of blood through the LAD to the heart. The invention thus facilitates the anastomosis construction by keeping the surgical site free of blood while preventing ischemia and reducing overall patient trauma.
Although the present invention is described herein in the performance of anastomosis surgery involving a graft of an internal mammary artery (IMA) to a LAD, it is to be understood that the invention and associated techniques are equally applicable to performing anastomosis constructions or surgical grafts on body vessels other than the LAD-IMA example employed herein for purposes of description.
Moreover, certain embodiments of the invention may be used in any medical application where a flow of fluid is desired to be maintained past an opening in the fluid conduit. Such applications occur in several surgical settings and other procedures both within the cardiovascular system and elsewhere.
The present invention comprises a distal perfusion device, hereinafter termed a “shunt” for ease of description, for use in LAD-IMA surgical procedures and the like. The shunt maintains blood flow in the LAD to prevent ischemia while maintaining a dry or blood free anastomosis site to facilitate a surgeon's suturing procedure. A shunt also provides support within the LAD if the LAD is ligated via sutures bordering the anastomosis site thereby decreasing trauma to the vessel. The shunt may also be configured with flanges, protruding edges, etc., to help expose the anastomosis to aid the positioning of a needle or otherwise further facilitate the suturing procedure.
To this end, the invention provides a microsurgical device, generally including a cylindrical central portion or member formed of a thin-walled, tube-like flexible material which includes a lumen therein to allow the flow of blood or other fluids through the central member. In preferred embodiments, selectively tapered end members are provided on either extremity of the central member, which extremities may be termed the proximal and distal extremities upon insertion in the LAD. The tapered end members include various configurations and perforations in the conical walls and/or in the apexes as well, as necessary to maintain the nominal blood flow through the shunt. The configuration of the opposing tapered ends facilitates the insertion of the shunt into an incision in the LAD, for example, by a surgeon using forceps. Since the shunt must be longer than the incision, that is, the anastomosis site, various shunts are installed in preferred embodiment by first inserting one end, generally of either end of the shunt, into the incision until the opposite end of
Cantu Alfredo R.
Gia Son M.
Krolic Jeff A.
Matheny Robert G.
Salahieh Amr
Buiz Michael
Cardiothoracic Systems, Inc.
Limbach & Limbach LLP
Woo Julian W.
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