Surgery: kinesitherapy – Kinesitherapy – Ultrasonic
Reexamination Certificate
1999-12-23
2002-08-06
Lateef, Marvin M. (Department: 3737)
Surgery: kinesitherapy
Kinesitherapy
Ultrasonic
C604S022000
Reexamination Certificate
active
06428491
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to invasive medical devices, and specifically to methods and devices for prevention and treatment of infections and thrombosis associated with the use of percutaneous, intravascular and intraluminal devices.
BACKGROUND OF THE INVENTION
Invasive devices such as catheters, central venous catheters, drug delivery tubing, porta-caths, etc., which are passed through body orifices or through an opening made in the patient's skin, are commonplace in medicine today. Such devices are referred to variously as “percutaneous,” “intravascular” or “intraluminal” devices. Inherent in their use is the risk of systemic infection secondary to the growth of bacteria in their vicinity, due to the introduction of bacteria with their insertion or bacterial colonization in vivo, and the fluid stasis that can occur with blockage and thus serve as nidus for infection.
Despite innovations such as the local application of antibiotics, infection continues to occur. The organisms involved in these infections are more resistant to antibiotic treatment, presumably due to a change of their membrane permeability when adherent to a catheter surface, or possibly due to other causes. Life-threatening systemic infections can occur as a result. Therefore, medical staff need to regularly remove these invasive devices, disinfect the area, and re-insert a new device. This leads to further concomitant risk of infection, as well as being unpleasant, expensive, and vexing to both staff and patient. A device that would markedly decrease or totally eliminate the need for repetitive catheter replacement, could prove extremely beneficial and allow for a significant decrease in the associated morbidity as noted heretofore.
The accepted means of preventing or treating bacterial contamination is through the use of antibiotics. At the same time, it is widely recognized that the bacteria sequestered in a biofilm that forms on a medical implant are much more resistant to antibiotics than their planktonic counterparts. There have been reports that impregnation of catheters with antiseptics or antibiotics may be helpful in reducing bacterial colonization on the catheter and related bloodstream infection. A recent report to this effect was presented by Veenstra et al., in “Efficacy of Antiseptic-Impregnated Central Venous Catheters in Preventing Catheter-Related Bloodstream Infection,” published in the
Journal of the American Medical Association
, Vol. 281 (1999), pp. 261-267, which is incorporated herein by reference.
Studies have shown that the addition of low-frequency ultrasound simultaneous to the application of antibiotics enhances the effectiveness of the antibiotic in killing the bacteria. In vitro experiments to this effect were reported by Qian et al. in an article entitled, “The Effect of Ultrasonic Frequency upon Enhanced Killing of
P. aeruginosa
Biofilms,” published in the
Annals of Biomedical Engineering
, Vol. 25 (1997), pp. 69-76, which is incorporated herein by reference. The authors found that when ultrasonic energy was applied to bacteria sequestered in a biofilm in conjunction with administration of an antibiotic (gentamicin), a significantly greater fraction of the bacteria were killed than by the antibiotic alone. Ultrasound by itself was not found to have any significant effect on the bacteria.
Similarly, Pitt et al. reported in an earlier article entitled “Ultrasonic Enhancement of Antibiotic Action on Gram-Negative Bacteria,” in
Antimicrobial Agents and Chemotherapy
Vol. 38 (1994), pp. 2577-2582, which is incorporated herein by reference, that a synergistic effect was observed when ultrasound was applied in combination with gentamicin to in vitro bacterial biofilms. The authors suggest that these results may have application in the treatment of bacterial biofilm infections on implant devices. Ultrasound by itself was not found to be effective in inhibiting bacterial growth, except possibly at power levels high enough to cause cavitation (which would therefore damage surrounding tissues in the body, as well).
There have been a number of reports on the use of ultrasound in the treatment of wounds in vivo. For example, Yudin et al., in “A Comparative Description of Effectiveness of Middling and Low Frequency Ultrasound in Treatment of Festering Wounds,” published in
Vestnik Khirurgii
(1995), pp. 63-64, report that ultrasound can have a bactericidal effect in treating wound infection. Similar results were reported by Ukhov et al., in “Indices of Immunity in Treating the Infected Wounds by Low-Frequency Ultrasound,” published in
Klin. Khir
. (1990), pp. 10-12. Komrakov et al., in “The Use of Ultrasound and Antibiotics for the Treatment of the Wounds in Patients with a High Risk of Vascular Graft Infection,” in
Klin. Khir
. (1990), pp. 10-11, report that low-frequency ultrasound in combination with gentamicin was effective in reducing the level of bacterial wound colonization following vascular graft. All of these articles are incorporated herein by reference.
Clinical ultrasound systems are mainly used for imaging, although there are also some therapeutic devices in use and others that have been suggested in the patent literature. For example, Talish, in PCT patent application PCT/US98/07531, whose disclosure is incorporated herein by reference, describes apparatus for ultrasonic bone treatment. The apparatus includes a therapeutic ultrasonic composite comprising a transducer and an integrated circuit unit positioned adjacent thereto. In operation, the apparatus is placed against the skin adjacent to a wound area, and driving signals are transmitted to the transducer for the creation of therapeutic ultrasound in the area of the bone. Another device of this type, for promotion of vascularization and epitheliazation of a wound inside the body, is described by Duarte et al., in U.S. Pat. No. 5,904,659, whose disclosure is also incorporated herein by reference.
A number of ultrasound devices for percutaneous and intrabody medical use have also been suggested. For example, PCT patent application PCT/IL97/00159, to Ben Haim et al., describes a self-aligning catheter, which uses ultrasound transducers inside the catheter to guide insertion of the probe through physiological tissues.
Tachibana et al., in PCT patent application PCT/US97/19993, whose disclosure is incorporated herein by reference, propose an intraluminal wall drug delivery device. A catheter, which is inserted into a blood vessel for this purpose, comprises at least one puncturing element that is laterally extendable to the catheter's longitudinal axis at its distal end, an ultrasound emitter, and an introducer element that introduces medication into an injection site that is in or beyond the vessel wall. The introducer element delivers a drug for treating local stenosis in the vessel, while the ultrasound emitter generates ultrasound in order to improve the distribution of the drug in the area of the stenosis.
U.S. Pat. No. 5,725,494, to Brisken, whose disclosure is incorporated herein by reference, describes an ultrasonic catheter with a resonantly-vibrating assembly at its distal end for treating vascular clot and plaque. The distal end is positioned in the area of a clot or stenosis in a blood vessel, and the vibrating assembly administers ultrasonic energy to break up the clot or other stenotic lesions. The catheter may also be used in conjunction with a therapeutic agent.
SUMMARY OF THE INVENTION
It is an object of some aspects of the present invention to provide methods and devices for reducing the risks of infection and thrombosis associated with the use of invasive medical devices, and particularly for reducing risks of infection and thrombosis within a lumen into which the invasive device is inserted and in a vicinity of the lumen.
It is another object of some aspects of the present invention to provide methods and devices for treating infection, thrombosis or clotting associated with such invasive devices.
It is a further object of some aspects of the present inv
Lateef Marvin M.
Mantis Mercader Eleni
Nixon & Vanderhye P.C.
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