This invention relates to endoscopic cardiovascular surgical procedures and instruments, and more particularly to apparatus including a vacuum-assisted cannula and surgical instruments operable therewith, and to surgical procedures utilizing such apparatus.
The injection of undifferentiated satellite cells or myocytes or stem cells into the myocardium of a beating heart in the endoscopic procedure of cellular cardiomyoplasty must be performed carefully to avoid complications. A specialized instrument, as described in the aforecited applications, is advanced through an operating channel of an endoscopic cannula to deliver cells in controlled manner into a beating heart. If a needle is used to inject the cells, sufficient control must be provided to ensure that the needle does not puncture a coronary vein or artery and cause hemorrhage within the pericardial space, with subsequent cardiac tamponade. Movement of the beating heart further complicates needle placement because of erratic movement of the coronary vessels as needle insertion is attempted. Similarly, placement of other elements such as epicardial pacing or defibrillation leads into the myocardium of a beating heart must be carefully placed to avoid puncture of a coronary vein or artery with concomitant complications.
In accordance with the illustrated embodiments of the present invention, a substantially rigid cannula includes separate elongated lumens extending between distal and proximal ends of the cannula to provide an instrument channel and one or more separate vacuum channels that terminate in a suction port located adjacent the distal end of the cannula. The instrument channel is sized to accommodate various surgical instruments including a hollow needle for penetrating the myocardium to deliver the cells. The needle is configured for shallow penetration to avoid puncturing into a chamber of the heart with associated complications. In an alternative embodiment, an instrument channel carried by a ‘needle’ is sized to accommodate epicardial pacing or defibrillating leads. Additionally, the cannula with separate lumens or channels therethrough may be in incorporated with or disposed within an instrument channel of an endoscopic cannula that houses an endoscope aligned with a distal transparent tip. This assemblage of surgical instruments may be conveniently positioned through tissue disposed between a subxiphoid incision and a surgical site on the epicardium of a beating heart, or positioned through tissue disposed between a thoracotomy incision and a surgical site on the epicardium of a beating heart. In some cases, a laterally expandable sheath may be employed to form a working cavity in tissue to facilitate the placement of the vacuum port and associated instrument channel at the surgical site on the epicardium.
a is a partial side view of a split needle according to one embodiment of the present invention;
b is a partial side view of a needle with short bevel sharpened tip according to an embodiment of the present invention;
a and 6b comprise a flow chart illustrating a surgical procedure in accordance with the present invention;
Referring now to
The superior channel 11 is sized to accommodate slidable movement therein of a hollow needle 21 that may exhibit lateral flexibility over its length from the needle hub 23 at the proximal end to the sharpened distal end 25. When used to inject cells, the needle 21 may be about 22-25 gauge in diameter and includes an internal bore of sufficient size to facilitate injection of cells without incurring cell damage, or lysis. When used to place pacing or defibrillating leads, the needle 21 may be about 2-2.5 mm in diameter with an internal bore of sufficient size to accommodate a lead of diameter up to approximately 2 mm in diameter.
Due to the relatively large diameter of the needle for epicardial lead placement (approximately 2-2.5 mm in diameter), a solid obturator 20 may optionally be used with the slotted needle 21, as illustrated in
After the lead is implanted in the heart by the procedure described above, the proximal end is disposed out through the small initial incision in the patient. The proximal end may then be tunneled subcutaneously from the initial incision to an incision in the patient's upper chest where a pacemaker or defibrillator will be located. A small, elongated clamp is passed through the subcutaneous tunnel to grasp the proximal end of the epicardial lead to facilitate pulling the lead through the tunnel for placement and attachment to the pacemaker or defibrillator.
Both the superior channel 11 and the needle 21 may be longitudinally slotted for placing an epicardial lead that may incorporate a large diameter connector, as illustrated in
The structure according to this embodiment of the invention, as illustrated in
As illustrated in
The configuration of the suction pod 17 and the needle 21 on the insertion cannula 10 also facilitates delivery of substances or devices in an orientation perpendicular to the epicardial surface. For placement of pacing or defibrillation leads, it is particularly desirable to have the leads enter the myocardium in an orientation that is generally perpendicular to the epicardial surface for secure anchoring in the myocardium. Generally, the insertion cannula 10 is advanced through the endoscopic cannula 27 and approaches the epicardial surface of the heart at a tangential angle. Accordingly, the insertion cannula 10 is configured to facilitate deforming the epicardial surface in order to achieve perpendicular entry of the needle 21 into the myocardium, as illustrated in
Referring now to
As illustrated in
A needle stop may also be built into the proximal end of the needle 21. Such a stop may simply be the hub 23 of the needle, and the needle 21 may be sufficiently limited in length that only a specific length of needle, for example 1 cm, may extend out of the instrument channel of the cell insertion cannula 10 when the needle hub 23 abuts against the proximal face of the instrument channel 11. However, the distal visual and tactile marker 30 provides generally more precise guide to depth of needle penetration under conditions of different angles of possible needle insertion with respect to the epicardial surface. With an extremely shallow angle of entry, a needle of short length may not enter the heart at all. In use, the transparent tip 31 and the suction pod 17 of the assembled cell injection device may be manipulated to reshape a localized portion of the epicardial surface of the heart to allow perpendicular entry of the needle into the myocardium, as illustrated in
The insertion device may also inject substances other than cells. Angiogenic agents such as vascular endothelial growth factor (VEGF) may be injected into myocardial scar tissue in an attempt to stimulate neovascularization, or growth of new blood vessels into the area. Insertion of the needle itself into myocardial tissue may be therapeutic as a form of transmyocardial revascularization (TMR). It is believed that needle insertion injury may stimulate angiogenesis, or growth of new vessels into a devascularized portion of the heart. The cell insertion cannula thus promotes accurate placement of a needle 21 into myocardium under continuous visualization. When combined with the endoscopic cannula, the needle placement may be accomplished through a small, 2 cm subxiphoid skin incision.
The illustrated embodiment of the insertion cannula includes a substantially rigid cannula containing a closed channel 9 ending in a distal suction pod 17, and a superior instrument channel 11 ending immediately proximal to the suction pod 17 on the closed channel 9. In operation, a long needle is advanced through the instrument channel 11. The needle 21 contains a marker 30 immediately proximal to its beveled tip 25 that serves as a visual or other sensory indicator of the depth of needle insertion. The marker 30 may be a segment of expanded diameter to provide tactile feedback upon insertion into myocardial tissue. For example, a gold-colored metallic sleeve 30 may be welded or soldered onto the needle 21 to provide both visual and tactile feedback of the depth of penetration of the needle tip into the myocardium. The marker may alternatively include a series of rings etched in the needle or a band etched or sandblasted in the same area. A three-way valve 15 on the cannula 9 allows suction in the pod 17 to be turned on or off, and allows irrigation fluid such as saline to be injected through the suction pod 17 while suction is turned off.
Referring now to
The left atrial appendage is frequently the site or source of thromboemboli (blood clots) that break away from the interior of the left atrial appendage and cause a stroke or other impairment of a patient. An ablation probe 41 can be used in the cannula 35 to shrink and close off the appendage to prevent thromboemboli from escaping.
In a similar procedure, a suture loop or clip can be placed through the cannula 35 and applied tightly around the atrial appendage to choke off the appendage.
The suction channels 39 in the cannula 35 of
In this configuration, an injection needle 21 slidably disposed within the central bore 37 may be extended beyond the distal end of the cannula 35, within the visual field of an endoscope, in order to orient the needle in alignment with a surgical target site on the pericardium prior to positioning the distal end of the cannula on the pericardium and supplying suction thereto to temporarily affix the cannula 35 in such position. A cannula 35 formed of transparent bioinert material such as polycarbonate polymer facilitates visual alignment of the cannula 35 and the central bore 37 thereof with a surgical site, without requiring initial extension of a surgical instrument, such as a cell-injection needle, forward of the distal end within the visual field of an endoscope. In an alternative embodiment, the central lumen or bore 37 may serve as a suction lumen with multiple injection needles disposed in the outer lumens 39.
Referring now to the flow chart of
An endoscopic cannula, for example, as illustrated in
After one or more injections of the myocardium, positioned and performed as described above, the injection cannula and the needle supported therein are removed 67 through the instrument lumen of the endoscopic cannula which is then also retrieved 69 from the working cavity, and the initial subxiphoid entry incision is then sutured closed 71 to conclude the surgical procedure.
The endoscopic cannula and pericardial entry instrument may also be applied from a thoracotomy incision to gain access to the heart. A 2 cm incision is performed in an intercostal space in either the left or the right chest. Ideally, the incision is made between the midclavicular line and the anterior to mid axillary line. The incision is extended through the intercostal muscles and the pleura, until the pleural cavity is entered. The endoscopic cannula is then inserted into the pleural cavity and advanced to the desired area of entry on the contour of the heart, visualized within the pleural cavity. The pericardial entry instrument and procedure as described in the aforementioned applications are used to grasp the pleura, and a concentric tubular blade cuts a hole in the pleura, exposing the pericardium underneath. The pericardium is then grasped by the pericardial entry instrument, and the tubular blade is used to cut a hole in the pericardium, allowing access to the heart. The transparent tapered tip 31 of the endoscopic cannula 29 aids in pleural and pericardial entry by retracting lung and pleural tissue that may impede visualization of the pericardial entry site. Once the pericardium is entered, the endoscopic cannula 29 may be moved around to visualize anterior and posterior epicardial surfaces.
Therefore the surgical apparatus and methods of the present invention provide careful placement of an injection needle or other surgical instrument on the surface of a beating heart by temporarily affixing the distal end of a guiding cannula at a selected position on the heart in response to suction applied to a suction port at the distal end. The guiding cannula can be positioned through a working cavity formed in tissue between the heart and a subxiphoid or other entry incision to minimize trauma and greatly facilitate surgical treatment of a beating heart. Such treatments and procedures may include needle punctures of the myocardium, or injections therein of undifferentiated satellite cells, or other materials, to promote vascularization or tissue reconstruction, for example, at the site of a previous infarct. Such treatments and procedures may also include placing of pacing or defibrillating leads into the myocardium. Such treatments and procedures may further include positioning and manipulation of an ablation probe to ablate myocardial tissue and correct cardiac arrhythmias.
This application is a divisional application of application Ser. No. 10/140,309, filed on May 6, 2002, which is a continuation-in-part of pending application Ser. No. 09/635,721, filed on Aug. 9, 2000 by A. Chin, which claims the benefit of the filing of provisional application Nos. 60/150,737, on Aug. 25, 1999, and 60/148,130 on Aug. 10, 1999, each of which applications is incorporated herein in its entirety by this reference.
Number | Date | Country | |
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60150737 | Aug 1999 | US | |
60148130 | Aug 1999 | US |
Number | Date | Country | |
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Parent | 10140309 | May 2002 | US |
Child | 12347802 | US |
Number | Date | Country | |
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Parent | 09635721 | Aug 2000 | US |
Child | 10140309 | US |