Surgery – Endoscope – Having auxiliary channel
Reexamination Certificate
2002-01-07
2004-03-30
Leubecker, John P. (Department: 3739)
Surgery
Endoscope
Having auxiliary channel
C600S129000, C600S153000
Reexamination Certificate
active
06712759
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates generally to surgical devices for introduction into a patient in minimally invasive surgery. More particularly, the present invention relates to medical endoscopes and, even more particularly, to a continuous flow endoscope sheath assembly.
2. Background Art
Minimally invasive surgery reduces patients' surgery-induced trauma, pain, and infection risk. Minimally invasive surgery typically is performed through one or more portals, such as a body orifice or a small incision formed in the patient's body. The portals provide for introduction of surgical devices, such as endoscopes that allow viewing of the surgical site. The surgical instruments enable examination, therapeutic action, and operative actions. The therapeutic actions include, among other things, irrigating, suctioning, cutting, cauterizing, coagulating, vaporizing, retracting, stapling, and sampling tissue. The instruments may also provide operative actions such as distention of a body cavity, substance ingress, and substance egress.
By minimizing invasiveness, procedures are safer and atraumatic, patients recover more quickly, hospital stays are shortened, and health care costs may be decreased. Accordingly, minimizing invasiveness continues to be of importance, and there is a continuing need for devices and methods that achieve this objective.
One significant barrier to further minimization of invasiveness is that in many procedures, the instruments must have fluid inflow and outflow channels. These channels effectively add to the outer diameter of the instruments. For example, known endoscopic instruments provide inflow/outflow through an assembly of concentric sheaths that define channels for inflow and outflow of fluids to and from the operative or surgical site. For example, the fluid may be an irrigating solution that helps maintain a clear view of the site for the physician. Certain known irrigating systems provide continuous and simultaneous inflow and outflow. These systems are known as “continuous flow” systems.
The known continuous flow endoscope systems generally introduce an irrigating fluid into the surgical site from an external source. For this purpose, the endoscope has an inflow channel defined by the inner surface of the inner sheath. The fluid passes through the channel and exits the distal end of the sheath to irrigate the operative site. Fluid at the surgical site may be withdrawn through an outflow channel defined by the outer surface of the inner sheath and the inner surface of a surrounding outer sheath. The outflow channel initiates at the distal end (front end) of the instrument and transports fluid to an exit point at the proximal end of the outer sheath.
Examples of continuous flow systems include: U.S. Pat. Nos. 3,835,842; 5,392,765; 3,835,842; 4,920,961 (discloses a latching system for connecting inner and outer sheaths to each other and for connecting the inner sheath to a base element); 5,486,155 (discloses a rotatable continuous flow endoscope sheath); 5,320,091; and 5,392,765 (discloses a continuous flow cystoscope with a front top inlet). The foregoing patents are incorporated herein by reference in their entireties for all purposes, and more particularly to show certain devices that could be adapted to include the features of the present invention. (This incorporation by reference is not intended to be an admission that any referenced patent is prior art that would render claims appended hereto unpatentable.)
Looking more particularly at the known devices, the outflow channel has a main distal aperture for withdrawing fluid. The aperture may be defined by the distal end points of the inner sheath or outer sheath (whichever has its distal end in a proximal position relative to the distal end of the other) and the points on the inner or outer sheath that are on common perpendicular lines off the longitudinal axis of the outflow channel. In other words, if the inner sheath is recessed within the outer sheath, and all points on the distal end of the inner sheath lie in a single plane transverse to the longitudinal axis of the inner sheath, then the aperture for the outflow channel is defined by the transverse plane through the inner sheath and extending through the surrounding outer sheath. This is the case, for example, in U.S. Pat. No. 3,835,842, where the distal end of the outer sheath extends distally beyond the distal end of the inner sheath (represented in FIG.
9
). In other cases, as seen in U.S. Pat. No. 4,132,227 (represented in FIG.
10
), the distal end of the inner sheath extends distally beyond the distal end of the outer sheath. The points on the distal end of the outer sheath do not lie in a single plane. Therefore, the outflow aperture does not have points that lie in a single transverse plane, i.e., the aperture initiates at a distal location and terminates at a proximal location. A significant drawback of this arrangement is that the aperture, which generally has an annular profile because it is defined by the space between sheaths, has a limited area for outflow. Increasing the space between sheaths to increase the outflow area would necessitate a corresponding increase in the outer diameter of the sheath assembly. This, of course, runs contrary to the objective of minimizing invasiveness.
There has been some effort to address the foregoing problem, but it has not been adequate. In known devices, in addition to a main outflow aperture at the front end of the device, the outer surface of the outer sheath has one or more lateral outflow apertures for passing fluid from the exterior of the outer sheath into the outflow channel. It is significant that in the known devices, these secondary outflow apertures on the outer sheath are disposed proximal (behind) the inflow aperture at the distal (front) end of the inner sheath. This is largely because the outflow holes would necessarily be positioned sufficiently proximal from the distal structure of the inner sheath so as to provide for unimpeded outflow through the holes and into the outflow channel between inner and outer sheaths. As a consequence, these lateral outflow holes generally lie well proximal to the inflow aperture. Unfortunately, there are inherent, unresolved disadvantages in tip portions having outflow apertures disposed proximal to the inflow aperture. For example, tissue or debris at the surgical site may press against the lateral outflow apertures, blocking them. This reduces outflow capacity.
In endoscopes such as resectoscopes, which are used with electrosurgical throughput devices, such as cutting, coagulating, or vaporizing electrodes, the distal tip portion of the inner or outer sheath assembly includes a dielectrical tip. The dielectrical tip insulates the electrode element from the outer and inner sheaths, which are generally made of electrically conductive metal. In general, the tip is a tube-like extension of the outer or inner sheath. However, the tip may take other configurations, such as a partial tube, beak, shield, etc. In the known devices, the insulative tip does not provide lateral apertures for outflow. Therefore, lateral outflow apertures in the known devices are situated even further behind the inflow aperture, and provide inadequate outflow at the distal tip portion of the endoscope. This is particularly disadvantageous where such instruments are used in tight anatomical spaces.
Another disadvantage of having a dielectrical tip placed on the end of the inner sheath is that common dielectrical materials are brittle and prone to fracturing when the inner sheath is physically withdrawn from the outer sheath.
For at least the foregoing reasons, there is a significant need for improved outflow systems in endoscopes and other invasive medical instruments requiring outflow functions, and particularly in endoscopes used with electrosurgical throughput devices where dielectrical tips must be used.
SUMMARY OF THE INVENTION
The present invention overcomes the aforementioned disadvantages by providing an improved outflo
ACMI Corporation
Ganz Bradley M.
Ganz Law PC
Leubecker John P.
Wolfe James L.
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