Graduated intraluminal catheter and methods of use thereof

Details Graduated intraluminal catheter and methods of use thereof Graduated intraluminal catheter and methods of use thereof

2000-08-16

2003-08-19

Bockelman, Mark (Department: 3763)

Surgery

Radioactive substance applied to body for therapy

Radioactive substance placed within body

Reexamination Certificate

active

06607477

ABSTRACT:

FIELD OF THE INVENTION
The field of the invention is a catheter which is insertable into or through a subject's urethra, or into or through another pre-existing or artificial bodily lumen of an animal, for a diagnostic or therapeutic purpose.
BACKGROUND OF THE INVENTION
The use of catheters, including multi-lumen catheters, is known for many therapeutic and diagnostic medical purposes. For example, the use of urethral catheters, including multi-lumen urethral catheters, is known in the art of urology. Such urethral catheters are useful for delivering compositions, including radioactive compositions, to the urethra of a subject (e.g. Harada et al., 1993
, Rad. Oncol
. 11:139-145; Skarlatos et al., 1994
, Urol. Int
. 53:209-213). However, the use of prior art urethral catheters is limited by the ability of the practitioner to accurately identify the position of a tissue in need of radiation treatment with respect to the position of the catheter and the ability of the practitioner to accurately position a radiation source within a urethral catheter to deliver radiation to the tissue. Furthermore, prior art urethral catheters do not permit use of a first catheter to determine the position of a tissue of the subject, removal of the first catheter, and use of a second catheter to accurately provide a composition to the position of the tissue without determining the position of the tissue a second time.
Intracavitary Brachytherapy
Various apparatus and techniques are known in the art of brachytherapy for exposing an animal tissue to a radioactive material using a conduit placed in a cavity of the animal. By way of example, bronchial, esophageal, rectal, vaginal, and arterial conduits have been described (e.g. Raju et al., 1993, Int. J. Radiation Oncology Biol. Phys. 27:677-680).
A serious limitation of prior art intracavitary brachytherapy methods has been the inability of such methods to enable accurate and reproducible placement of radiation sources in close proximity to a tissue in need of such treatment. Significant shortcomings of prior art intracavitary brachytherapy catheters include the tendency of the catheter to move within the bodily lumen and the inability of practitioners to accurately determine both the location of a relevant tissue relative to the catheter and the location of a radiation source or pharmaceutical composition within or along the catheter. Typical prior art methods have involved attempting to identify the position of a relevant tissue, thereafter attempting to position a catheter near the relevant tissue, and thereafter attempting to position a radiation source or pharmaceutical composition within or along the catheter near the relevant tissue.
A limitation on the use of radiation and other potentially cytotoxic medical treatments is the lack of cytotoxic specificity. Radiation or drug delivered near a relevant tissue may induce death of cells in both the relevant tissue and other tissues which are located in close proximity to the relevant tissue. Because of the inaccuracy of prior art intracavitary brachytherapy methods for directing treatment only to relevant tissue, as described above, prior art methods have required the use of excess amounts of cytotoxic agents so that death of relevant tissue cells will be effected even if the agent is not accurately placed. Use of excess cytotoxic agent, however, induces damage in non-relevant tissue. Collateral damage to non-relevant tissues could be avoided if the cytotoxic agents could be delivered more accurately to relevant tissues. Accordingly, there is a great need for devices, kits, and methods for accurately delivering cytotoxic agents to relevant tissues while minimizing delivery of the agents to surrounding tissues.
The prostate is a solid organ which surrounds the urethra of the male human between the base of the bladder and the urogenital diaphragm. Benign prostatic hypertrophy (BPH) is a common condition among male humans aged 45 or older. Prostate cancer is a leading cause of death among males, and can frequently be diagnosed with the aid of a simple blood antigen-detecting test. Radiation therapy and prostatectomy are the primary treatments available for prostate cancer and prostatectomy is currently the primary treatment for BPH. Prostatectomy has numerous drawbacks, which have been widely described in the art. External beam irradiation of the prostate for the treatment of localized prostate cancer is associated with small bowel injury, radiation proctitis, and urethral stricture (Gibbons et al., 1979
, J. Urol
. 121:310-312). At least two groups have employed transurethral radiation therapy as a supplement to external beam irradiation of localized prostate cancer tissue (Harada et al., 1993
, Rad. Oncol
. 11:139-145; Skarlatos et al., 1994
, Urol. Int
. 53:209-213). In addition, another group has employed transurethral radiation therapy as a sole treatment for recalcitrant BPH-related urine retention (Koukourakis et al., 1994, Med. Dosimetry 19:67-72). Each of these groups employed ultrasonography, computerized tomography, or fluoroscopy imaging methods to identify the tissue to be treated or to confirm the position of the radiation source relative to the tissue to be treated. Identification of the location of tissue in need of treatment and placement of a radiation source using one of these imaging methods is dependent upon the deformability of the tissues being imaged, the body posture of the subject during the identification or placement, the position of the imaging device, and other factors which may not be easily replicated.
Failure to precisely control the amount and location of transurethrally-delivered radiation can result in damage to the urethra itself or to other organs located in close proximity thereto, including the bladder and the prostate. It is thus critical to identify the position of a tissue in need of treatment and the location of radiation source as accurately as possible.
Urethral and Ureteric Stricture
Urethral stricture is a common complication of urological procedures, particularly following urethral intervention by a urologist (Baskin et al., 1993, J. Urology 150:642-647; Stormont et al., 1993, J. Urology 150:1725-1728). Formation of a urethral stricture is thought to involve disruption of the urothelium, followed by hypertrophy of urothelial or other tissues, resulting in stenosis. A urethral stricture may also be formed by hypertrophy of a tissue located in close proximity to the urothelium, such as prostate tissue or corpus spongiosum penis tissue in male humans or muscle tissue or spongiose erectile tissue in female humans. Non-limiting examples of urological interventions known to be associated with urethral stricture include transurethral resection of the prostate, radical prostatectomy, external beam irradiation of prostate tissue, and other urological interventions which disturb the urethra. Non-limiting examples of diseases or disorders known to be associated with urethral stricture include BPH, prostate cancer, and urethral cancer. Further details of tissues which comprise the urethra or which are located in close proximity thereto in the human are found in, for example, Williams et al., eds. (1980
, Gray's Anatomy
, 36th ed., W.B. Saunders Co., Philadelphia, pp. 1408-1409).
Known treatments for urethral strictures include surgical modification of the urethra, laser-assisted modification of the urethra, urethroplasty, and urethral stent implantation (Bosnjakovic et al., 1994, Cardiovasc. Intervent. Radiol. 17:280-284; Badlani et al., 1995, Urology 45:846-856; Mundy, 1989, Brit. J. Urology 64:626-628; Quartey, 1993, Ann. Urol. 27:228-232).
Ureteric stricture is another known complication of urological procedures and of disease and disorder states. Ureteric strictures may involve hyperplasia or hypertrophy of any of the tissue layers of a ureter, namely the fibrous layer, the muscular layer, or the mucous layer, or may involve hyperplasia or hypertrophy of a tissue or organ located in close proximity to a ureter. Further details of tissues which compri

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