Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical energy applicator
Reexamination Certificate
1999-04-30
2001-06-19
Kamm, William E. (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical energy applicator
Reexamination Certificate
active
06249707
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a method and apparatus for the percutaneous introduction of a paddle style lead into the space near the spinal cord of a patient. More specifically, this invention relates to the introduction of a paddle style lead whereby the paddle style lead is stiffened during introduction and implantation and becomes flaccid once implanted. Moreover, this invention relates to the percutaneous introduction of the paddle style lead into the spinal column area through a needle with an oblong cross section.
2. Description of Related Art
Spinal cord stimulation is used to treat a multitude of disorders including multiple sclerosis, spinal cord injury, cerebral palsy, amyotrophic lateral sclerosis, dystonia, torticollis and other neurological disorders. Spinal cord stimulation is also useful for treating pain including intractable malignant and nonmalignant pain. Neural stimulation electrodes and leads implanted in the epidural space of the spinal cord of a patient stimulate selected locations of the spinal cord for treatment of pain and various conditions.
Surgically implantable paddle style leads, or flat leads, and percutaneous insertable wire leads for the spinal cord have been in use for some time. These paddle style, or flat leads, and wire leads are used for electrical stimulation of neurons in the spinal cord. Two types of leads are generally used for spinal cord stimulation: 1) wire and 2) paddle.
Typically, a wire lead is introduced into the spinal column using a needle and a stylet assembly. The needle and stylet are inserted into the spinal column area between adjacent vertebrae until the tip of the needle and stylet are advanced into the epidural space of the spinal column area. The stylet is withdrawn and a wire lead is inserted through the open area or lumen of the needle and into the epidural space to a selected location adjacent to the spinal cord. Some needle and stylet assemblies have a curved distal tip to facilitate introduction of the lead at an angle to the axis of the lumen portion of the needle. The needle typically has a side opening or orifice at its distal end for insertion of the lead into the selected location of the spinal cord. In some assemblies, the stylet may fill the entire lumen cavity including the side opening of the needle to prevent the collection of tissue in the lumen cavity during insertion of the needle. The stylet can also provide rigidity to the needle body for use during insertion.
Current needle technology requires that all leads be of a circular cross section in order to be placed through the lumen portion of the needle into the epidural space. Needles used for insertion of the wire leads typically have a circular cross section between 14 and 18 gauge.
The paddle style or flat leads are generally rectangular shaped flat paddles that must be surgically implanted. To introduce a paddle style lead into the epidural space percutaneously using needle insertion, the paddle lead must be rolled to a circular shape to slide through the typical circular cross section needle. The method of rolling the paddle lead and inserting through a needle and unrolling the paddle style lead has not been perfected for use. The only way to insert a paddle style lead is by a surgical procedure known as a laminotomy, a laminectomy, or similar surgical procedure. Because the paddle style lead must be surgically implanted, anesthesiologists may not perform the procedure.
Accordingly, there remains a need in the art for a non-surgical method of inserting a paddle style or flat lead into the spinal cord area.
SUMMARY OF THE INVENTION
The present invention recognizes and provides a solution to the problems associated with the percutaneous introduction of paddle style leads. The invention provides a unique needle for percutaneous insertion of a paddle style lead into the spinal column area. Additionally, the invention provides a method of stiffening the paddle style lead to facilitate insertion of the lead in the spinal column area. Briefly, the present invention comprises a needle for percutaneous insertion having a lumen with an oblong cross section sized to receive a paddle style lead and a temporary stiffening feature for the paddle lead.
Accordingly, an object of the present invention is to provide a non-surgical method and apparatus for percutaneous insertion of paddle style leads that may be utilized by both surgeons and anesthesiologists. Current needles used for introduction of leads for electrical stimulation have a round cross section. Paddle style leads cannot be inserted through these needles. The paddle style lead must be inserted by a surgeon performing a laminotomy, a laminectomy or similar surgical procedure where the surgeon cuts open the tissue and then slides the lead into the proper position. This novel invention uses a needle having a lumen with an oblong cross section. A flat, paddle style lead based on current lead technology is passed through the oblong cross section of the lumen in this needle for introduction into the spinal column area. This invention allows for percutaneous insertion through a needle without performing the above mentioned surgical procedures.
Another object of this invention is to provide a less traumatic procedure for patients during the implantation of paddle style leads for treatment. Surgical introduction of leads for electrical stimulation is traumatic for patients. Insertion of leads for electrical stimulation utilizing an oblong needle that is inserted near the spinal column is less traumatic for patients than surgery where the surgeon must cut the tissue open and then slide the lead into the proper position.
Yet another object of this invention is to provide a method and apparatus for a paddle style lead with a stiffening member to facilitate insertion through the oblong cross section of the lumen of the needle. A stiffening stylet can be used to stiffen the paddle style lead. Another alternative is to use a continuous ribbon style lead such that the cross section of the lead body is the same as the cross section of the paddle. This procedure and apparatus is not limited to use with any specific paddle style or flat lead and can be used for introduction of leads into other areas.
A further object of this invention is to provide a paddle style lead that remains relatively stiff during implantation and positioning and becomes relatively flaccid once inserted. Lead paddles that are stiff during implantation and flaccid while implanted can be a substantial benefit during the introduction of longer lead paddles and as an improvement to current insertion procedures. A stylet, or any other suitable, temporary stiffening method, that may be reversed after implant, will aid the physician in steering the paddle to the desired location and avoid buckling should the physician need to advance the paddle lead from one spinal segment to the next.
Yet another embodiment of this invention is to provide for stiffening the paddle style lead using temperature controlled materials. The lead is composed of at least one temperature controlled material and the temperature controlled material remains relatively stiff when at temperatures below a persons body temperature and the same lead becomes relatively flaccid after heating to at least body temperature after insertion. A relatively stiff paddle improves insertability while a flaccid lead is desired once inserted.
The full range of objects, advantages, and features of the invention are only appreciated by a full reading of this specification and a full understanding of the invention. Therefore, to complete this specification, a detailed description of the invention and the preferred embodiments follow, after a brief description of the drawing wherein additional objects, advantages and features of the invention are disclosed.
REFERENCES:
patent: 4141365 (1979-02-01), Fischell et al.
patent: 4270549 (1981-06-01), Heilman
patent: 4285347 (1981-08-01), Hess
patent: 5255691 (1993-10-01), Otten
patent: 5618287
Cross, Jr. Thomas E.
Kohnen Jane Lambie
Banner & Witcoff , Ltd.
Kamm William E.
Medtronic Inc.
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