Bone anchor

Details Bone anchor Bone anchor

2001-04-05

2003-10-21

Lewis, Ralph A. (Department: 3732)

Surgery

Instruments

Orthopedic instrumentation

Reexamination Certificate

active

06635058

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a bone anchor, bone anchor screw, and an inserting device for use in medical applications, and particularly in medical suturing. The invention is especially useful in treating female urinary stress incontinence, although it can be utilized with other medical applications as well.
BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART
Urinary stress incontinence, i.e., the inability to control urination from the bladder, is a distressing problem for more than ten percent of elderly women as well as for many young women. This condition frequently arises in the following manner: in a normally anatomically positioned bladder, the proximal urethra and the bladder are in pressure continuity with the abdominal cavity, so that an increase in abdominal pressure is transmitted both to the bladder and to the proximal urethra, resulting in normal continence. However, particularly among elderly women, the bladder and the proximal urethra tend to descend from their normal anatomic positions such that the bladder neck and proximal urethra move away from the posterior wall of the pubic bone. When this occurs, the proximal urethra is no longer in pressure continuity with the abdominal cavity; therefore, an increase in intra-abdominal pressure (e.g. by laughing or coughing) results in an increase in intravesical pressure, but no change in the urethral closing pressure, thereby producing so-called stress incontinence. It also appears that as the bladder descends, the urethra becomes shorter and curved, so that its radial tonic muscle contraction is reduced, contributing to incontinence. Another pathology may arise from urethral sphincteric damage.
The surgical treatment for stress incontinence involves bladder neck suspension. One treatment is by an open surgical operation, involving an incision in the abdominal wall and/or anterior vaginal wall, to reposition and suspend the bladder and proximal urethra to their normal anatomic positions. This is done by suspension of the bladder neck and periurethral tissue to the posterior wall of the pubic bone. In another surgical procedure, the bladder neck is elevated by suspension of suture threads passing, with the aid of long needles, from both sides of the urethra and the bladder neck to the lower abdominal fascia or superior pubic bone ramus.
In prior patent application Ser. No. 08/150,517 filed Nov. 10, 1993 and its continuing application (the disclosures of both of which are hereby incorporated by reference) the inventors have disclosed apparatus and method(s) which allows treatment of stress incontinence by incisionless per vaginal bladder neck suspension. As disclosed therein, an inserter device can be utilized for ejecting and implanting a staple or bone anchor through the vaginal tissue to enter the pubic bone. In another embodiment, as further discussed hereafter, an inserter device can be used to install a bone anchor by screwing the bone screw into the pubic bone, with or without vaginal incision. The suture thread that is secured to the bone anchor, staple or bone screw, suspends the bladder neck and the periurethral tissue to the posterior wall of the pubic bone.
It has been found, however, in stapler devices, and especially those that require high impact for bone implantation, that the ejection of the staple from the device causes the stapler to recoil. As is apparent from basic physics, the action of ejecting the staple from the stapler is associated with a reaction force which forces the inserter/stapler, and the hand of the individual (the physician) implanting the same, to move backwards. As a result, the physician must take this recoil into account and use force to firmly press the stapler against the pubic bone to ensure that the bone anchor is properly and effectively ejected and implanted. Anyone familiar with carpentry-type staple guns is familiar with this recoil. If pressure is not placed over the head end of the stapler, and the surface into which the staple is driven is hard (as in the case of bone), the staple will not be fully implanted, but, rather, the user's hand will recoil. The medical stapler should also be held perpendicular to the bone surface. The stapler must be held in that position with the stapler held firmly during and through the ejection process so that the stapler does not shift its position as a result of the recoil. Otherwise, undue movement of the stapler because of recoil can result in a staple being ejected in an incorrect orientation, or incompletely ejected into the bone of the patient. This problem is especially apparent where the material into which the staple is ejected is bone and the physical confines of the space where the medical physician's hands are working is limited, i.e., within a vagina.
Similarly, where the inserter is a screwdriver type and the anchor is a screw type anchor, unless a hole is pre-drilled in the insertion site, constant firm pressure must be applied through the axis of the anchor (perpendicular to the pubic bone) to assist the self tapping property of the anchor to facilitate insertion during screwing. The medical screwdriver type inserter must, therefore, be held in the correct position relative to the patient's anatomy through the insertion process.
A purpose of the present invention is to provide leverage, which facilitates a constant pressure at the insertion site to minimize the effect of this recoil, increasing the ease of use of an inserter device in a medical procedure (whether a pusher or impact type inserter, or a screw inserter), and increasing an inserter device's effectiveness. This furthers the self-tapping property of the bone anchor, whether it be an impact type or screw type anchor. A screw type inserter device increases the ease of use of an inserter device in a medical procedure and increases the present stapler device's effectiveness.
A further purpose of the present invention is to provided leverage in the per vaginal insertion of a bone anchor into the pubic bone. The present invention allows the physician to employ a pulling force perpendicularly against the pubic bone of the patient, and to conveniently do so with one hand. The leverage, degree of accuracy and ease of insertion are believed to be significantly enhanced by the present invention.
In one embodiment, the invention relates to per vaginal bone screw insertion without drilling a hole in the bone by use of a non-linear or C-shaped inserter having a rotating intravaginal head for per vaginal bone screwing with or without vaginal wall incision. An additional purpose of the present invention is to provide a screw type bone anchor and related device and procedure for per vaginal incisionless or minimal incision bladder neck suspension.
SUMMARY OF THE INVENTION
The present invention addresses the difficulties experienced in the prior art by providing a “C”, “V” or other non-linear insertion shaped device for use in medical applications, and especially, per vaginal insertions of anchors of any type into the pubic bone of a patient. The insertion device, which may be rigid or flexible, is positioned during use so that force may be applied through the axis of the anchor. The weight of a patient can contribute to the force applied by the physician to firmly press the device against the patient's anatomy, so as to minimize the effects of the problems normally associated with recoil. Although the present device is directed toward a stapler device for use to eject a staple type bone anchor, it will be appreciated that the pusher/driver portion of the device can alternatively be used to insert a screw type bone anchor and will be useful in other applications as well.
Accordingly, it is an object of the present invention to provide an insertion device which minimizes recoil during ejection of a bone anchor into bone.
It is further an object of the present invention to provide an insertion device which minimizes recoil during per vaginal insertion of a bone anchor into the pubic bone and otherwise allows constan

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