Medical procedures often require obtaining access to internal regions of the body. For this purpose, it is common to use a catheter inserted through either a natural body orifice or through an incision. One example is in coronary angioplasty in which a catheter is inserted through the femoral artery to the desired region of the heart where the angioplasty procedure is carried out. Typically, the catheter has a preshaped distal end portion of a configuration designed to facilitate reaching the desired region of the heart. During insertion of the catheter, a guide wire is used, and the guide wire straightens the preshaped distal end portion. However, once the catheter is near the desired location, the wire is removed so the distal end portion of the catheter can return to its preformed shape to facilitate access to the desired coronary artery.
A similar approach is used in catheterizing the fallopian tubes utilizing a transcervical approach. For example, it may be necessary or desirable to access the fallopian tubes for the infusion of a contrast dye for fluoroscopic evaluation, the placement of another catheter in which embryos, zygotes or other genetic material are deposited within the fallopian tubes, the canulation of guide wires for tubal occlusions and the insertion of an endoscope.
One prior art approach utilizes a single-lumen catheter having a curved distal end portion in the unstressed condition. To insert the catheter, a mandrel is passed through the through lumen to straighten and stiffen the catheter. In this straightened and stiffened condition, the catheter is passed through the cervix, and the catheter is oriented in the direction of the desired ostium. Once oriented, the mandrel is removed completely from the catheter, and this allows the catheter to return to its preformed, curved shape. A medical procedure can then be carried out through the lumen.
If procedures must be carried out in both fallopian tubes, it is necessary to reinsert the mandrel through the lumen to straighten the catheter, reorient the catheter with respect to the other ostium, withdraw the mandrel and then carry out the desired procedure. Alternatively, the catheter used for the first fallopian tube may be withdrawn and a second catheter may be utilized for the second fallopian tube.
One problem with this procedure is that the mandrel must be removed from the lumen and replaced with some other instrument in order to carry out the medical procedure, and this increases the time required. This replacement procedure also adds complexity and may require an additional staff member to complete. The procedure becomes even more time consuming and complex when both ostia must be accessed. In addition, if a second catheter is used for the second ostia, the cost of the procedure is increased. If the same catheter is removed, straightened and reinserted, there is an added danger of infection as a result of the reinsertion through the vaginal cavity.
It is also known to employ a pull wire to curve the distal end portion of a normally straight catheter. However, these catheters are not likely to have the rigidity required to pass through the cervix.