Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/32—Surgical cutting instruments
  • A61B17/3203—Fluid jet cutting instruments
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/00234—Surgical instruments, devices or methods, e.g. tourniquets for minimally invasive surgery
  • A61B2017/00238—Type of minimally invasive operation
  • A61B2017/00243—Type of minimally invasive operation cardiac
  • A61B2017/00247—Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
  • A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
  • A61B2018/00345—Vascular system
  • A61B2018/00351—Heart
  • A61B2018/00392—Transmyocardial revascularisation

Definitions

• the present application relates to a fluid jet system and method for use in cardiac surgical applications.
• Fluid jet cutting systems which employ high pressure streams of liquid, such as water have been utilized in various surgical applications, for example, to disintegrate eye lens tissue (see U.S. pat. no. 3,930,505), to break down and remove tumors (see U.S. pat. no. 5,037,432), and to dislodge, emulsify and remove deposits from a vein or artery (see U.S. pat. no. 5,370,609).
• the use of waterjets in surgical procedures offers a cost-effective, precise tool which delivers the stream of liquid to the surgical site.
• new instrumentation and techniques are being developed to utilize water jets in new procedures in place of more conventional surgical instrumentation.
• Transmyocardial revascularization is a procedure used to restore blood flow in patients with vascularization deficiencies in the heart muscle (myocardium).
• myocardium vascularization deficiencies in the heart muscle
• a surgeon cuts or drills a network of holes (channels) through the myocardium of the left ventricle which allows the blood inside the heart to enter the myocardium.
• channels typically, between six to twenty channels, about 1 mm in diameter each, are drilled though the myocardium using a high-powered laser.
• the channels may either be drilled from the outside of the heart into the ventricle (thoracotomy approach), or from the ventricle outward (percutaneous approach, hereinafter, "PMR").
• the holes in the surface of the heart are closed by clotting which is promoted either by applying external digital pressure, or by placing epicardial purse-string sutures over the opening.
• the channel does not penetrate the outer surface of the ventricle.
• the surgeon In the thoracotomy approach (the most common approach to date), in order to drill channels into the heart the surgeon first aims the laser at the targeted site, arms the device, and then fires the laser, preferably between heartbeats (when the heart is gorged with blood), so that the blood in the ventricle will act as a backstop, absorbing the energy of the laser and preventing the laser's energy from inadvertently damaging other tissue. Firing between heartbeats also results in drilling through the myocardium at the point in the cardiac cycle at which the tissue of the myocardium is the thinnest. The firing of the laser is usually computer controlled from the cardiac waveform to insure that the laser is fired at the appropriate time.
• the present invention is directed to a system and method for generating a high pressure fluid jet for cutting or drilling into the heart, particularly during TMR/PMR procedures, to provide controlled, accurate and fast drilling with little or no dissipation of heat to surrounding tissue.
• the system preferably includes a variable pressure pump for creating a high-pressure fluid jet which drills channels in the heart at predetermined depths corresponding to the pressure and duration of the jet, with multiple pulses, increased duration, and/or increased pressure increasing the depth of the channel.
• the size or diameter of the hole is determined by the stand-off distance of the nozzle from the surgical site, the design of the nozzle and the diameter of the nozzle's orifice.
• the system also preferably includes a console for housing the pump and other control mechanisms which allows the surgeon to input information into the system, for example to selectively vary the diameter of the jet stream, the pressure of the jet, the desired depth of the cut into the heart, and the like, thereby allowing the system to be customized by the surgeon depending upon the details of the application.
• a console for housing the pump and other control mechanisms which allows the surgeon to input information into the system, for example to selectively vary the diameter of the jet stream, the pressure of the jet, the desired depth of the cut into the heart, and the like, thereby allowing the system to be customized by the surgeon depending upon the details of the application.
• the configuration and pressure of the fluid jet may be adjusted according to the particular procedure and desired cut, with the effective diameter of the jet preferably being up to approximately 1 mm in diameter for TMR PMR procedures.
• the jet may be delivered as a coherent, hair-thin jet, or may assume other configurations, such as an outwardly spreading spray, or a plurality of jet streams which may converge on a focal point, depending upon the desired orientation and shape of the jet channels.
• several inter-changeable instruments or catheters may be provided to allow the surgeon to choose a particular instrument depending upon the particular application.
• the drilling solution may include water, physiological saline, a liquefied gas such as carbon dioxide, or other drilling media. In one embodiment, the drilling solution may contain additives to achieve certain functional purposes.
• the fluid jet may contain angiogenic factors for inducing vascularization.
• Other functional additives may include, but are not limited to, contrast agents for image visualization, denaturing agents for strengthening holes drilled in tissues, anti-infectives for treating or preventing infections, drugs to prevent myocardial shock, vasoconstricting compounds to reduce bleeding, anesthetic compounds to reduce pain, solutions of various salts to achieve an electrolyte balance with the blood, and/or other functional additives.
• the system also preferably includes a high pressure fluid delivery tube for conducting the pressurized stream to a distal end of the system, to deliver the drilling jet to the myocardium.
• the delivery tube may be flexible for ease of manipulation by the user, allowing the user to position the fluid jet relative to the heart and also may include means for guiding the tube, such as by a guidewire or a guiding catheter. If the procedure is performed with the thoracotomy or thoroscopic approach (TMR), the distal end of the tube is preferably in the form of an instrument dimensioned to fit through a port of an endoscope.
• the distal end When utilized percutaneously (PMR), the distal end preferably is in the form of a flexible, guidable catheter, preferably with an articulated or movable nozzle, and may also include a metallic tip or marker, so as to be visible by angioscopy.
• PMR percutaneously
• the variable pressure pump which drives the cutting fluid may preferably include a reusable component and a disposable or limited use component, which allows the portion of the pump which directly contacts the drilling fluid to be separate from the other components. In this manner, the pumped fluid communicates only with the disposable component, allowing for contamination-free reuse of the pumping system by simply replacing a spent disposable component with a fresh, sterile one.
• the pump preferably operates in the range of 10 to 50,000 psi, so that the pressure and velocity of the fluid jet can be selectively controlled between a pinpointing pressure (about 10-500 psi) having no significant drilling affect on the heart, before increasing the pressure to within the drilling range (about 700-50.000 psi) after the target has been pin-pointed by the non-drilling jet.
• pinpointing may optionally be utilized to selectively space the channels drilled into the heart, but it is not necessary to pinpoint the target before drilling.
• the pump is designed so that for a given pressure, a single pulse of liquid will drill into the heart at a predetermined depth, for example one pulse may equal a 2 mm deep hole. Multiple pulses are utilized to increase the depth of the cut, for example two pulses in the above example would drill a 4 mm deep hole.
• the pump is designed so that the flow of liquid through the pump is continuous with the flow being "gated" or diverted to the surgical site for a controlled duration of time in order to drill into the heart at a predetermined depth, the longer the flow is diverted, the deeper the cut. Both embodiments allow for precise drilling into the heart with the flexibility of increasing the depth of the holes, if necessary.
• the fluid jet system is designed for use in a TMR procedure to drill one or more channels into the myocardium of the heart.
• the fluid jet system is designed for use in a PMR procedure to drill one or more channels into the myocardium of the heart.
• the fluid jet system utilizes a drilling solution containing additives to achieve certain functional purposes.
• the components of the system are detachable allowing for the interchange of various components, as desired. It is an object of the present invention to provide a fluid jet drilling system for cardiac applications which is operable at high pressures and which may be utilized in TMR and/or PMR procedures.
• Fig. 1 is a schematic of a fluid jet drilling system according to the present invention specifically configured for use in surgical applications;
• Fig. 2 is an illustration of the variable high pressure pump illustrated in Fig 1 ;
• Fig. 3 is a sectional illustration of the disposable pump cartridge component of the variable high pressure pump;
• Fig 4 is a top view of a latching mechanism which secures the cartridge to a reusable component of the variable high pressure pump.
• a fluid jet cutting system 10 for use in cardiac surgical procedures, for example TMR and or PMR procedures, is illustrated in Fig. 1.
• the system 10 preferably includes a variable pressure pump 24 (Fig. 2) for creating a high pressure fluid jet which drills channels in the heart at predetermined depths corresponding to the pressure and duration of the jet, with multiple pulses, increased duration, and/or increased pressure increasing the depth of the cut.
• the system 10 also preferably includes a console 22 for housing the pump and other control mechanisms which allows the surgeon to vary the parameters of the system by inputting information to the control circuitry, for example by the use of dials or buttons on the console.
• Such parameters may include, for example, the desired pressure and size of the jet, the desired depth of the cut into the heart, or the inclusion of functional additives to the jet, thereby allowing the system to be customized by the surgeon depending upon the details of the application.
• the system 10 also preferably includes a high pressure fluid delivery tube 36 for conducting the pressurized stream to a distal end of the system adjacent the heart to deliver the fluid jet to the surgical site (heart).
• high pressure delivery tube 36 may be connected at one end 37 to a surgical jet instrument 40.
• Surgical instrument 40 preferably includes a body 41 defining a lumen in communication with delivery tube 36, and further includes one or more jet orifices 43 in communication with the lumen.
• the instrument 40 may be designed for thoroscopic use, and as such may preferably be dimensioned to fit through a port of an endoscope.
• the instrument 40 may preferably be in the form of a flexible, guidable catheter for ease of manipulation through the arteries leading to the heart thereby allowing the user to manually position the fluid jet relative to the heart.
• the catheter may preferably include an articulated or movable nozzle, and may be made of a medical-grade plastic or metal (for example, a shape memory alloy) and may also include a metallic tip or marker, so as to be visible by angioscopy.
• the tip 44 of the surgical instrument 40 may be selectively moldable allowing a surgeon to reshape or bend the jet tip 44 into variable configurations, including angular orientations, to facilitate positioning of the nozzle relative to the surgical site. This feature is especially attractive where the operative field is difficult to reach, allowing the tip of the instrument to reach around obstructions.
• the surgical instrument, and more particularly the tip of the instrument preferably has a low-profile, slender configuration to facilitate use of the instrument in small openings and narrow spaces which may confine the operative field.
• the one or more jet orifice(s) may be disposed axially or transverse with respect to the lumen of the instrument and may be dimensioned as a small diameter opening, in order to produce a hair-thin fluid jet.
• the diameter of the orifice may be in the tenths of millimeters to drill holes up to about 1 mm in diameter.
• the size or diameter of the hole is determined by the stand-off distance of the nozzle from the surgical site (i.e. the distance between the nozzle and the surgical site), the design of the nozzle and the diameter of the nozzle's orifice.
• the stand-off distance in the present embodiment is preferably in the range of approximately 0-5 mm and is most preferably approximately 2mm.
• the surgical instrument may be releasably secured to delivery tube 36 to allow varying instruments to be utilized with the system. For example, instruments having varying diameter orifices, or having different pre-shaped tips may be utilized. Alternatively, the tip of the surgical instrument may be releasably secured to the body of the instrument to allow the tip to be changed.
• the surgical instrument delivers the high-pressure fluid jet to the surgical site in a precise manner.
• the fluid may include water, physiological saline, or a liquefied gas such as carbon dioxide, or other cutting media.
• the fluid may be delivered at lower drilling pressures to pinpoint the target and irrigate the surgical site, if desired.
• the fluid may also contain additives for achieving certain functional purposes.
• the fluid may contain a contrast agent for image visualization, angiogenic factors for inducing vascularization, denaturing agents for strengthening holes drilled in tissues, anti-infectives for treating or preventing infections, drugs to prevent myocardial shock, vasoconstricting compounds to reduce bleeding, anesthetic compounds to reduce pain, solutions of various salts to achieve an electrolyte balance with the blood, and/or other functional additives.
• the high pressure delivery tube 36 is connected at a second end 38 to a pumping system 24 which provides the high pressure cutting fluid to the delivery tube 36 and the instrument 40.
• Fig. 2 illustrates, in detail, the two component pumping system 24 which is preferably housed in console 22, and which may include both a reusable component 57 and a disposable component 59.
• the pump is designed so that for a given pressure, a single pulse of liquid is delivered which will drill into the heart at a predetermined depth, for example one pulse may equal a 2 mm deep hole. Multiple pulses are utilized to increase the depth of the cut, for example two pulses in the above example would drill a 4 mm deep hole.
• the pump is designed so that the flow of liquid through the pump is continuous with the flow being "gated” or diverted to the surgical site for a controlled duration of time in order to drill into the heart at a predetermined depth, the longer the flow is diverted, the deeper the cut. Both embodiments allow for precise drilling into the heart with the flexibility of increasing the depth of the holes, if necessary.
• the reusable component preferably includes a reciprocating plunger 60 which pushes against a flexible, disposable diaphragm 86 (Fig. 3) which is part of the disposable pump cartridge 28.
• a positive displacement, motor-driven plunger is illustrated as the reusable component, other pumping mechanisms, such as an air intensifier, are contemplated as would be apparent to one of ordinary skill in the art.
• the console 22 may also house shaft 52, driven by a motor 29 which is connected to an eccentric crank 56 mounted on shaft 52, and which is engaged to one end of an elongated linkage rod 58.
• the other end of linkage rod 58 is preferably connected to plunger 60 by pin 62.
• Bearings 34 may additionally be provided at each linkage connection to minimize friction between the respective moving parts.
• the plunger 60 is preferably made of a carbide-containing material or other wear- resistant material as would be apparent to one of skill in the art.
• a cylindrical chamber 64 preferably including a carbide-containing insert, is dimensioned to receive plunger 60.
• the clearance between the chamber 64 and the plunger 60 is about 0.0002 inches, with the diameter of the plunger being about 0.50 inches.
• Rotation of shaft 52 causes the eccentric crank 56 to move the linkage rod 58, thereby reciprocating the plunger within the chamber 64.
• the distance between the plunger in an extended position and a retracted position is the length of the stroke. In the present embodiment, the stroke is about 0.1 inches.
• the disposable component of pump 24 preferably includes disposable diaphragm cartridge 28, or piston pump, which is illustrated in Fig.
• the cartridge 28 preferably includes flexible diaphragm 86, supported by a semi-rigid cone 87 which is mounted in a conical recess disposed in the lower surface 88 of cartridge 28.
• a variable sized pumping chamber 89 is defined by the deformable diaphragm for receiving cutting fluid therein.
• the diaphragm When disposed within console 22, the diaphragm is preferably seated against the mouth of cylindrical chamber 64 so that retraction and extension of the plunger will cause the diaphragm to flex between a fill and an ejection stroke to pump the fluid from the fluid source, into the pumping chamber and to the delivery tube 36, as described in greater detail below.
• the diaphragm is preferably made from a medical grade polyurethane, while the semi-rigid cone may be made of type 304 or 316 stainless steel, or a polymer such as fiber-filled hard plastic, the cone preferably being bonded or press fit into position.
• the pump cartridge 28 may be mounted into a compatible socket or opening 26 (Fig. 1) in the console housing 27 and may be securely retained in the console by a locking lever 140 and latch 148, side views of which are shown in Fig. 2.
• a safety switch (not shown) may also be provided on the lever to prevent the operation of the pump when the lever is in the unlocked position.
• Fig. 4 shows a top view of an exemplary latching mechanism.
• the cartridge further includes an inlet passage 100 which preferably extends between an inlet port 101 communicable with a sterile source of fluid and the flexible pumping chamber 89, and also includes an outlet passage 112 which preferably extends between an outlet port connected to one end of high pressure delivery tube 36, and the pumping chamber 89.
• the inlet port 101 is connected to one end a fluid delivery tube 32.
• Delivery tube 32 is connected at its other end to the source of cutting fluid, such as a saline bag 30 suspended from an IV pole (Fig. 1).
• a one way valve 98 may preferably control the flow of fluid into the chamber during the fill stroke, while preferably preventing backflow into the sterile fluid source.
• a one-way valve 114 may, likewise, control the flow of pumped fluid out of the pumping chamber during the ejection stroke.
• the system is first prepared by the user who inserts the pump cartridge 28 into the console housing prior to surgery, with the cartridge aligned so that the diaphragm 86 drapes over the chamber 64.
• the user then secures the cartridge to the console by engaging the locking lever 140 with the latch 148 which also acts to deactivate the safety switch and compresses the seal between the diaphragm 86 and cone 87 in a leaktight fashion.
• a tube 32 running from a fluid bag may then be connected to the inlet of the cartridge and the burst-resistant delivery tube 36 may be attached to the outlet of the cartridge.
• the drilling site on the heart muscle (myocardium) is identified and the patient is anesthetized and prepped in a conventional manner. If the procedure is thoroscopic, a trocar is inserted through the rib cage of the patient, and an endoscope is place through the trocar to provide visualization of the heart muscle through the endoscope.
• the desired surgical jet instrument is chosen and may then be inserted through a port on the endoscope.
• the surgical jet instrument is provided in the form of a flexible, guidable catheter, preferably with an articulated or movable nozzle.
• the surgical jet catheter To deliver the surgical jet catheter percutaneously, it is typically inserted through the femoral artery, into the aorta and then into the left ventricle.
• the catheter preferably includes a metallic tip or metallic marker so that the catheter is visible by angioscopy as it is inserted into the femoral artery and advanced to the surgical site.
• the user may pre-select either a non-drilling or drilling pressure, depending upon whether pinpointing the target prior to drilling is desired. If pinpointing is desired, the jet beam is introduced at a low, non-drilling pressure while the drilling site is pin-pointed. When the jet beam and target coincide, the pressure of the stream may be increased to within the drilling range of pressure to drill a hole in the myocardium.
• the drilling pressure is pre-selected to drill a hole only through the wall intended for drilling, so as to not injure other parts of the heart.
• the depth of the hole corresponds to the pressure and the pulse duration of the of the fluid jet, with multiple pulses increasing the depth of the hole, or for gating the longer the flow is diverted, the deeper the cut.
• the user may select the desired depth by turning the appropriate control knob to the desired depth, as indicated on the control console.
• the size or diameter of the hole is determined by the stand-off distance of the nozzle from the surgical site, the design of the nozzle and the diameter of the nozzle's orifice.
• the stand-off distance in the present embodiment is preferably between 0-5 mm and is preferably 2mm.
• the plunger will begin to retract, thus reducing the pressure in the pumping chamber.
• the reduced pressure causes the inlet check-valve to open, allowing sterile fluid to fill the pumping chamber.
• Extending the plunger increases the pressure in the pumping chamber, opening the outlet check-valve and driving the pressurized fluid out through the outlet check-valve, into the deliver)' tube and ultimately, the surgical instrument.
• the pressurized fluid flows out of the instrument as a single pulse, while in another embodiment, the flow of liquid is continuous through the pump with the flow being diverted to the surgical site for a controlled duration of time.
• the pump speed may be selectively controlled by the user via a control dial, a foot 20 or hand switch (not shown), allowing the pressure and cutting strength of the fluid jet to be varied, during the procedure, as desired.
• the target is ready to be drilled.
• the instrument is triggered by the user to deliver the drilling jet to heart.
• blood is entrained in the fluid jet as the hole is drilled. Entraining the blood allows the holes to fill more rapidly with blood, thus promoting the angiogenic factors and the formation of new blood vessels.
• Other functional additives may also be introduced into the fluid jet at this time, as described above. If the procedure is percutaneous, once in the ventricle the cutting jet is delivered at a pre-selected pressure for drilling only the myocardium, and preferably through most of the myocardium, but not for complete penetration.
• the cutting jet is delivered at a pre-selected pressure for drilling the myocardium, and preferably complete penetration of the myocardium is achieved. Penetration may be timed to occur between heartbeats, if desired, but this is not necessary.
• the surgeon then moves the instrument to the next position to drill the next hole and repeats the process until, preferably, a plurality of holes are drilled according to the needs of the patient.
• the disposable pump head Upon completion of a surgical procedure, the disposable pump head is detached from the reusable console and discarded or resterilized for reuse.
• the plunger which does not contact the sterile fluid, may then be reused with a new, sterile pump cartridge.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Surgery (AREA)
• Heart & Thoracic Surgery (AREA)
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• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
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• 1998
  • 1998-12-30 CA CA002315673A patent/CA2315673A1/en not_active Abandoned
  • 1998-12-30 IL IL13664398A patent/IL136643A0/xx unknown
  • 1998-12-30 EP EP98965022A patent/EP1049511A1/de not_active Withdrawn
  • 1998-12-30 JP JP2000526256A patent/JP2003517325A/ja active Pending
  • 1998-12-30 WO PCT/US1998/027824 patent/WO1999033510A1/en active Application Filing
  • 1998-12-30 AU AU20221/99A patent/AU2022199A/en not_active Abandoned

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