Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-09-15
2003-06-17
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S022000
Reexamination Certificate
active
06579277
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to medical devices such as small diameter endoscopes, catheters, probes and/or other semi-rigid, semi-flexible instruments having an elongated insertion tube which is flexible, and more particularly to such devices which incorporate mechanisms for varying the stiffness of the device.
2. Description of Related Art
It is usually necessary to provide some amount of initial rigidity/columnar strength upon the initial insertion of a device (such as endoscopes, catheter devices, or probes) in order for the device to pass through natural or manmade orifices and passages without bending or buckling and enter the human body. Unfortunately, the initial rigidity of a device is usually too stiff to allow for and provide for residual flexibility within the human body, which includes many changes in direction.
The residual flexibility is necessary to ensure that the device does not puncture organs or vessels, and ensure that the device is able to follow the anatomical passages without causing injury to the passage. Furthermore, the introduction of flexibility to a given probe enables the device to accommodate small amounts of compression, so as to traverse bends in the anatomy, without inducing torsional/tearing forces on the tissue. For example, driving a straight, relatively stiff rod thought a tortuous vessel will induce tearing stresses on the vessel where the vessel has a large degree of directional change.
The present invention is particularly well suited for use with an ultrasonic probe operating in a transverse mode of operation, as described in our co-pending application Ser. No. 09/618,352, which was filed on Jul. 19, 2000 and is herein incorporated by reference in its entirety. In prior art devices, the application of ultrasonic energy has required that the inserted probe be relatively rigid. These relatively rigid probes were required to transmit ultrasonic energy, and limited the flexibility of the ultrasonic probe. Through the application of transverse ultrasonic energy, flexible ultrasonic probes are able to be produced. The present invention is particularly well-suited for use with these probes.
Prior art medical devices currently available are usually either too flexible or too stiff to easily manipulate within the human body and provide the aforementioned needs and issues. In the construction of prior art medical devices, the flexibility has been predetermined at the time of construction. The flexibility cannot be adjusted to suit specific anatomical or user conditions encountered in various medical procedures. This predetermined flexibility is based upon the diameter, wall thickness and durometer of the material used. Alternatively, where allowable, intricate steering and stiffening devices have been added to the instrument to influence the predetermined flexibility. Some examples of these steering/stiffening devices are wires embedded within a catheter tube that allow for directional changes to be caused by pulling/easing of the wires, and then to stiffen the device by applying equal retraction on the wires so as to cause compression on the column and inducing stiffness to it.
Furthermore, prior to the present invention the length of the flexible portion of the device—along with the strength modulus of the materials used in the probe construction determined the overall compression/deflection factor on the probe and the subsequent ability of the device to bow and bend and particularly how much prior to eventual breakage.
With reasons and necessity for a wider degree of flexibility within use in the human anatomy, it is desirable to provide a medical device wherein the stiffness thereof can be varied through a relatively wide range with a relatively simple and inexpensive construction.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to provide a medical device with variable stiffness, so that the device provides sufficient initial rigidity to allow initial insertion into a body, yet provides sufficient residual flexibility to allow manipulation within the human body. An object of the invention is to provide a single-use product. In this aspect of the invention, the method of construction and design has been directed towards those products which are considered to be single patient contact. This provides a device which does not require complicated methods of disassembly and cleaning procedures and processes prior to reuse of the device.
Another abject of the present invention is to provide a design with minimal incremental cost increases when compared to existing devices. This is important factor because of financial constraints placed upon the medical markets and healthcare reimbursement.
A further object of the invention is to eliminate the use and introduction of wires and or other devices within the lumen of the probe (if hollow) and eliminate any fixation or similar attachments to the exterior of the probe.
Another object of the invention is to minimize the size of the medical device. It is known that any increase in outer dimension significantly increases the circumference and hence contact with the human anatomy. Similarly, the portion of the medical device which penetrates the human body should be minimized to ensure that the device is (where appropriate) more comfortable, less traumatic and easily tolerated by a patient and/or fits within the confines of existing medical instrumentation.
For example, when inserting diagnostic instrumentation into the cervix of a human uterus, the smallest outer dimension is desired in order to preclude the need for cervical dilation. Unfortunately, the small diameter devices required for such procedures must be relatively flexible so as to preclude accidental puncture of the organ, as well as to be able to be deflected so as to reach anatomical landmarks. However this flexibility increases the degree of difficulty of insertion of the device, as well as subsequent manipulation. Thus, increasing the durometer, increasing wall stiffness and or diameter—with a result in the decrease in flexibility may assist in the introduction of the probe, but can cause a risk of damage.
Yet another object of the invention is to provide the ability to provide modification to the location of the maximum point of flexure along the probe. By having the ability to move or altering the location of the flexure point, the probe is able to maximize its utility within the human anatomy.
Another object of the present invention is to provide a device capable of the delivery of an active ultrasonic probe—where the thinner/softer wires are required for the effective positioning and delivery into the human anatomy. As the wires of an ultrasonic probe are made thinner and softer, the transmission of the ultrasonic energy may be reduced. The probe may, over the length of the active portion, start to exhibit undesired flexural modes or, may incur losses due to contact with soft acoustically absorbing materials.
A further object of the present invention is to provide the ability to modify the stiffness of an ultrasonic probe so as to allow for the insertion/manipulation of that probe within the confines of the human anatomy—while at the same time not reducing the stiffness such that it cannot/will not provide sufficient power to destroy tissue.
In accordance with these objects, a medical device such as an endoscope, catheter, or ultrasonic probe includes an insertion tube or trocar, which is adapted to penetrate into the human body. A trocar is a surgical instrument that contains two parts: a trocar sheath and an obturator. The trocar sheath is an outer thin walled tube that surrounds the obturator. The obturator contains a point or sharpened profile that is able to penetrate the human anatomy.
For convenience, the present invention is described in conjunction with trocars. However, trocars are merely used for illustration, and one skilled in the art will recognize that any alternative vascular access devices and instruments for percutaneous introduction and access
Rabiner Daniel E.
Rabiner Robert A.
Han Mark K.
Mendez Manuel
OmniSonics Medical Technologies, Inc.
Palmer & Dodge LLP
Smith Richard B.
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