Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-11-10
2002-08-13
Casler, Brian L. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S047000, C604S174000, C604S175000, C604S104000, C604S171000, C604S265000, C128SDIG008
Reexamination Certificate
active
06432100
ABSTRACT:
TECHNICAL FIELD
This invention relates to the generation of a protective sleeve against infections of a artificial lead that extends in the body of a patient. Specifically this invention relates to a new apparatus and method for the generation of a sterile protective sleeve for an percutaneous lead that extends through the skin of a human or animal patient.
BACKGROUND ART
A percutaneous lead is designed for an enduring connection between the external world and the inner space of the body. This is of importance for patients, who rely on such a connection for a diagnosis or a therapy. Such an application is, for example, the ambulant peritoneal dialysis. This treatment requires a permanent lead to the peritoneal cavity for the repeated exchange of dialysis fluid. This lead is sometimes called artificial lead through the skin or percutaneous lead.
Other applications are the artificial heart or an artificial cardiac assist system. These devices mostly require a tube penetrating the skin for the transport of air or electricity to energize the blood pump. A further application is the usage of the lead for the transport of biosignals, which are used for the stimulation of muscles or for sensory purposes.
All these long-term applications of an artificial lead through the skin are endangered by infection. Intense care of the percutaneous lead can alleviate these complication, but cannot completely eradicate the above mentioned dangers. Often percutaneous leads become so severely infected, that they have to be explanted. This operation endangers the life of the patient, if the infection invades deeply into the body.
The infections starts at the region, where the three phases—implant, body tissue and the microbe containing air—meet. That is the region, where the lead exits the body. At this three-phase line the microbes can be controlled initially by frequent cleansing and with bacteriostatica. But in the long-term, the microbes tend to form a biofilm at the surface of the artificial lead through the skin. This biofilm is a layer of microbes attached to the lead material. This layer protects itself by a mucus layer against the immune system. The body cannot fight against the infection because the biofilm is impenetrable for its defenses. The biofilm tends to expand. It grows in direction of the nutrition source. In this case, it is towards the inside of the body. As a result a pouch forms, which resists cleansing and which can result in a dangerous infection.
There are various artificial leads through the skin, which attempt to avoid this danger by a collar at the region where the lead exits the body. These collars are implanted just under the skin and should prevent the biofilm from invading. However, experience shows that the skin, nonetheless, retracts, exposing the collar and finally an infection can develop.
Further attempts have been made to avoid infections by covering the skin penetrating surface with porous surfaces, such as synthetic grafts, to encourage the ingrowth of cells. Clinical experience shows that these devices as well finally become infected.
In the patent DE 39 43 412 A1 the surface of the lead is covered by a porous textile, which is intended for an easy and sure ingrowth of cells by a decreasing porosity from the artificial surface to the tissue. Clinical experience shows, that this device as well finally becomes infected, because the tissue detaches from the artificial lead through the skin.
In the patent DE 197 28 489 A1 the surface of the lead is covered by an organic tissue made from collagen fibers or collagen polymer fibers. The basic idea is that the natural collagen encourages the ingrowth of tissue. Clinical experience shows that these devices as well finally become infected.
There are artificial leads through the skin with an easily movable three-phase line, which is made to reduce the mechanical force at the ingrowth cells. This is described in a publication of the inventor (Grosse-Siestrup, Ch., Affeld, K.: Design criteria for artificial percutaneous devices, Journal of Biomedical Materials Research, Vol 18, 357-382 (1984)). Clinical experience shows that these devices as well finally become infected in the long-term.
Hitherto all artificial leads through the skin can not prevent infections and the invading of microbes in the body in the long-term. They are accompanied with complications and endanger the patient.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a new percutaneous lead.
It is a further object of the present invention to provide a percutaneous lead that is operative to prevent infections.
It is a further object of the present invention to provide a percutaneous lead that is operative to prevent infections and microbes from invading the body
It is a further object of the present invention to provide a percutaneous lead that is operative to prevent the formation of a biofilm at the surface of the artificial lead through the skin.
It is a further object of the present invention to provide a percutaneous lead that is operative to prevent body tissues from separating from the percutaneous lead.
Further objects of the present invention will be made apparent in the following Best Modes for Carrying Out Invention and the appended claims.
The foregoing objects are accomplished in one exemplary embodiment of the invention by a device that comprises a protective sleeve against infections at the three phase line, which is formed continuously or in intervals and which is moving out of the body. The sleeve imitates one prominent feature of natural percutaneous structures such as fingernails: Growth from the inside of the body to the outside.
The bacterial biofilm, which tends to form at the three-phase line, where the sleeve exits the skin, is pushed outwards into an area of lower humidity and lower nutrition. There the biofilm is perishing. The regeneration of the three-phase line is achieved by a protective sleeve against infections, which is created inside the microbe free body. This protective sleeve against infections surrounds the lead where it penetrates the skin and separates the lead from the surrounding tissue.
The protective sleeve against infections is formed by a liquid or plastic material, which hardens upon contact with water vapor or other substances from the body. This material is preferably injected from outside of the body to the inside by a tube. Such a material is for example the silicon rubber RTV 3140 of DOW Corning, which cures at room temperature under the influence of water vapor. In this invention, the vapor of the surrounding tissue is used.
There exist different materials, which are transformed to elastomeric polyurethane by this process. These materials can be mixed with biologically active substances, which are diffused inside the body. For example, it is possible to add antibiotics, to achieve a microbe free tissue. Other substances can promote the adhesion of cells at the protective sleeve against infections.
The protective sleeve against infections, which is formed continuously or in intervals as described above, requires cutting of unwanted extensions very much like hair and fingernails. The advantage of the invention is the complete prevention of infections in the region of the lead through the skin.
REFERENCES:
patent: 4479795 (1984-10-01), Mustacich et al.
patent: 4959054 (1990-09-01), Heimke et al.
patent: 5156597 (1992-10-01), Verreet et al.
patent: 5308338 (1994-05-01), Helfrich
patent: 5911757 (1999-06-01), Seare, Jr.
patent: 2242033 (1999-01-01), None
patent: 39 43 412 (1991-07-01), None
patent: 197 28 489 (1999-01-01), None
Christian Grosse-Siestrup and Klaus Affeld, “Design Criteria for Artificial Percutaneous Devices,” Journal of Biomedical Materials Research, 1984, p. 357-382, vol. 18, John Wiley & Sons, Inc., USA.
Casler Brian L.
Parmelee Christopher L.
Rodriguez Cris
Walker & Jocke LPA
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