Apparatus and Method for Establishing Access to the Body
An apparatus and method for access to the inside of a body includes a transparent sheath with a radiopaque marking and fastener for securing a guidewire or catheter. The transparent sheath permits objects located within and near the sheath to be visualized with an external imaging system. Objects located near the sheath can also be observed with an imaging device disposed inside the sheath. The radiopaque marker permits accurate positioning of the sheath in the body. The sheath can be inserted into the body over an interventional device. A fastener prevents migration of a guidewire or catheter during the procedure.
This application claims the benefit of provisional application Ser. No. 60/077,624 filed on Mar. 6, 1998 and of provisional application Ser. No. 60/081,399 filed on Apr. 10, 1998 in the United States Patent and Trademark Office.
FIELD OF THE INVENTIONThe present invention relates generally to an apparatus and method for percutaneous access to the inside of the body. In particular, the invention relates to a transparent sheath with a radiopaque marking at the distal end and a fastener for securing a guidewire or catheter near the proximal end of the sheath.
BACKGROUND OF THE INVENTIONMedical procedures utilizing interventional instruments (e.g., endoscopes) inserted through the skin often require preservation of the access path after the instrument is withdrawn from the body. Typically, these procedures require insertion of a sheath into the body along a guidewire previously coupled to the interventional instrument. The sheath prevents the tract established by the interventional device from closing or collapsing. One example procedure involves insertion of a dilation catheter and a guidewire along the nephrostomy tract. Once properly positioned in the body, a balloon near the distal end of the catheter is inflated to dilate the tract. A sheath is then advanced through the nephrostomy tract before the tract substantially collapses.
This procedure has inherent problems. The sheath is typically radiopaque, thus the physician cannot observe objects within or obstructed by the sheath by standard fluoroscopic techniques. In addition, optical imaging devices inserted through the sheath are unable to look out radially, thus prohibiting accurate location of objects adjacent to the sheath. Moreover, the guidewire may migrate during the exchange of instruments through the sheath, thus inhibiting placement of additional instruments along the tract.
SUMMARY OF THE INVENTIONA transparent sheath for access to the inside of a human or animal body has been developed which is useful in a variety of medical applications including, but not limited to, the exchange of instruments, drainage of fluids and removal of objects (e.g., kidney stones). The sheath can be used to provide percutaneous access to the inside of the body or it can be used in natural body orifices. Applications include urological procedures, stent delivery and laparoscopic procedures. In one embodiment, the sheath includes an elongated hollow member with a radiopaque marking at the distal end. In another embodiment, the sheath includes an elongated hollow member with at least one radiopaque marking along the length of the sheath and one or more fasteners near the proximal end of the sheath for securing other medical devices thereon such as guidewires and catheters. The sheath can be optically or fluoroscopically transparent or transparent to ultrasound. Preferably, the sheath is transparent to all three visible light (including IR and UV lights), ultrasound, and x-rays. The radiopaque marking may be disposed on the outer or inner circumference of the sheath. The radiopaque marking may be disposed on an end face of the distal end or may occupy the whole length of the sheath such as a line or spiral. One or more additional radiopaque markings may be used for identification such as in a broken line, a series or rings, or alphanumerical characters disposed along the length of the sheath (e.g., product numbers and logos). An additional radiopaque line or spiral running the length of the sheath from the distal end to the proximal end may be used to enhance visibility during the procedure.
The distal end face may be approximately perpendicular to the longitudinal axis of the sheath. In an alternative embodiment, the distal end face and longitudinal axis may define an angle less than 90° to minimize trauma to the issue during insertion and facilitate placement of the sheath.
The transparent sheath may include one or more fasteners at its proximal end for securing other medical devices thereon such as a guidewire or catheter and maintaining the sheath at a desired position within the body. The fastener may be any device or adaptation at the proximal end of the sheath which prevents other medical devices from migrating during the procedure. Example fasteners include clips, slots, or straps such as Velcro™ straps or elastic bands or a combination thereof. In one embodiment, the fastener is a retaining slot which provides an interference fit to hold the other medical device. The retaining slot may also include an opening at the end of the slot which is opposite the proximal end face of the sheath wherein the opening accepts the other medical device and restricts its longitudinal movements back and forth or migration back out of the slot through an interference fit. In yet another embodiment, a magnet is disposed adjacent to the retaining slot to secure a ferromagnetic medical device such as a guidewire.
The invention also features a method for access to the inside of a body. The method includes the steps of inserting a first medical device through a body lumen, then inserting over the second medical device such as the transparent sheath of the invention. Once the sheath is disposed at a desired location in the body, the first medical device is secured to the second medical device in the fastener. In one embodiment, the first medical device is secured by an interference fit in an opening adjacent to an end of a slot disposed at the proximal end of the second medical device, the end of the slot being opposite the proximal end face. In another embodiment, the first medical device is secured within the slot by a magnet fixed adjacent to the slot.
The method may be used for naturally existing body lumens or body lumens created by the practitioner with the use of an interventional device such as a needle or a trochar. Thus, in one embodiment, the method of the invention permits access to the inside of a body percutaneously. The percutaneous method further includes the step of inserting an interventional device into the body. The interventional device may be coupled to a guidewire or catheter. Once, the lumen is created the interventional device is decoupled from the guidewire or catheter. A transparent sheath of the invention with a fastener near its proximal end and radiopaque markings along its length is inserted into the body over the guidewire or catheter. The interventional device is then removed from the body. In one embodiment, the sheath may be inserted into the body over the guidewire after removal of the interventional device. In another embodiment, the sheath may be inserted over the interventional device before its removal.
In yet another embodiment, the methods of the invention further include the step of viewing through the first medical device objects in the body relative to a radiopaque marking at the distal end. The invention also features a method of viewing objects within or near the first medical device in a body. Objects inside or near the first medical device are viewed relative to the radiopaque marking at the distal end with an imaging device or disposed along the length of the elongated hollow body. The imaging device may be located within the first medical device or be outside of the body. In one embodiment, the imaging device is a side-viewing endoscope placed within the first medical device. In another embodiment, the imaging device is a fluoroscopic imaging system viewing from outside the body.
In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.
Referring to
The elongated hollow member 12 can be made from any optically clear plastic. Urethane or rigid vinyl such as polyvinylchloride (PVC) are good sheath materials owing to their flexibility. Polycarbonate materials (e.g., Plexiglas) can also be used. At least a portion of the length of the elongated member 12 is optically and/or fluoroscopically transparent, semi-transparent, or translucent to permit visualization of objects within or near the elongated member 12. Suitable material for use in the sheath of the present invention have a transmittance of at least 20% and above at a given wavelength. The transmittance (Tr) is a standardized measurement of the percentage of light intensity transmitted (Ir) through a length (m) of material normalized by the intensity of the incident light (Io):
The length of the path traveled by the light through the material affects the transmittance value: in the same material, the longer the path is, the lower the transmittance will be, and vice versa. Thus, high transmittance materials may be used to form sheath with thicker walls, and still provide suitable transparency for observation through the walls of the sheath. Low transmittance materials may also be used either with thinner wall, or in conjunction with higher intensity incident light or higher sensitivity light receptors.
As an illustration,
Preferable materials also maintain sufficient rigidity at body temperature to maintain the body opening propped open. Suitable material will maintain a durometer of about 50-72 Shore D at body temperature. Softer materials may be used with reinforcing materials such as, rings, coils or braids to maintain the lumen open.
The radiopaque markings 18, including a marking 19 on the distal end face 14 at the sheath 10, permit visualization of the sheath 10 inside the track 27 with a fluoroscopic imaging system and facilitate accurate positioning of the sheath 10 within the body 22. The markings 18 and 19 can be coatings made from paints, inks, or films which contain materials opaque to the imager adhered, sprayed, or painted on the sheath. For example, the radioopaque substance is preferably metal components such as metal salts, metal oxide or elemental metal or mixtures of metal components in the form of particles or powders dispersed in the coating (e.g., barium, strontium, tantalum, tungsten, gold, iridium, stainless steel and platinum). Alternatively, the particles or powders are dispersed into a portion of the elongated hollow member 12 directly at the desired location. The markings 18 and 19 may also be pieces of opaque materials such as pieces of metal or foils inserted into recesses carved into the elongated hollow member 12 or disposed on either the inner or outer surface 36 and 38, respectively, of the elongated hollow member 12 and secured into place by glue, heat and/or a covering tape.
It should be understood in conjunction with the descriptions of fasteners for securing a guidewire described above that multiple retaining slots 24 can be used to secure multiple guidewires 20 to the sheath 10. Furthermore, it should be understood that safety wires, catheters, and other medical instruments having geometries resembling guidewires can be similarly secured to the sheath 10. In addition, clips, latches, magnets, small locking devices and other fasteners can be integrated or attached to the proximal end of the sheath 10 to secure guidewires, in place of, or in combination with, those described above.
Referring to
Referring to the flowchart of
Referring to the flowchart of
While the invention has been particularly shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims
1. A medical device for providing access to the inside of a human or animal body, comprising
- an elongated hollow member including a distal end and a proximal end and comprised of a transparent material;
- a radiopaque marking disposed on said elongated hollow body; and
- a fastener at the proximal end of said elongated hollow body to secure at least another medical device.
2.-27. (canceled)
Type: Application
Filed: Jan 21, 2010
Publication Date: May 13, 2010
Inventors: Yem Chin (Burlington, MA), Clifford M. Liu (Randolph, MA), Benjamin J. Bottcher (Franklin, MA), John B. Adams (Augusta, GA)
Application Number: 12/691,285
International Classification: A61M 25/00 (20060101);