1. Field of the Invention
The present invention generally relates to surgical instruments and, in particular, relates to surgical screws which are adapted for use with skeletal members, such as vertebrae, for example, and methods for their use.
2. Description of Related Art
Skeletal structures are formed of bones and adjoining structures which include cartilage, for instance. For various reasons, these skeletal structures may require artificial support or stabilization. For example, the human spine is composed of a column of thirty-three bones, called vertebrae, and their adjoining structures. The twenty-four vertebrae nearest the head are separate bones capable of individual movement and generally are connected by anterior and posterior longitudinal ligaments and by discs of fibrocartilage, called intervertbral discs, positioned between opposing faces of adjacent vertebrae. Each of these vertebrae include a vertebral body and a dorsal arch that enclose an opening, called the vertebral foramen, through which the spinal cord and spinal nerves pass. The remaining nine vertebrae are fused to form the sacrum and the coccyx and are incapable of individual movement.
It is well known in the prior art to utilize pedicle screws for posterior lumbar stabilization procedures. These procedures typically include inserting a pedicle screw posteriorly into the pedicle or pillar of the lumbar spine, and then connecting the screw to either plates or rods for stabilization of the lumbar spine for fractures, tumors and various degenerative conditions. A bone graft also can be added to help solidify the stabilization. When this procedure is used on osteoporotic patients, however, pedicle screw fixation is sometimes difficult to achieve because the threads of the pedicle screw are unable to properly secure within the material of the pillar.
Similar results also may be observed when attempting to secure surgical anchors within the material of other skeletal members.
An additional concern relates to the potential of violating the vertebral foramen while attempting to secure a surgical anchor within the material of a pillar.
Therefore, there exists a need for improved surgical screws which address these and other shortcomings of the prior art.
Briefly described, the present invention relates to surgical screws or anchors which are adapted for use with skeletal members. In a preferred embodiment, the surgical anchor includes an elongated body with a proximal end and a distal end, a passage extending at least partially through the body from the proximal end, and at least one hole extending at least partially through the body that communicates with the passage. The passage and the at least one hole are configured so that a material is receivable in the passage, preferably, at the proximal end of the elongated body. So configured, the material may be delivered through the passage, through the at least one hole, and into the skeletal member. Additionally, a cutting member preferably is arranged at the distal end of the elongated body, with the cutting member being configured to enable penetration of the at least a portion of the elongated body into the skeletal member.
Embodiments of the present invention also may be construed as providing methods for inserting an anchor into a skeletal member. In this regard, a preferred embodiment includes the steps of: (1) providing a first anchor having a proximal end, a distal end, and a cutting member, the cutting member being configured to enable penetration of the distal end into the skeletal member; (2) inserting the first anchor into the skeletal member to form an anchor-receiving hole; (3) checking for a violation of a wall of the skeletal member; (4) removing the first anchor from the skeletal member; and (5) inserting a second anchor into the anchor-receiving hole.
Other embodiments of the present invention may be construed as providing systems for lumbar spine stabilization. In this regard, a preferred embodiments includes a plurality of first anchors, with each of the first anchors incorporating a proximal end, a distal end, a cutting member, a passage, and at least one hole. Each of the cutting members is configured to enable penetration of the distal end of its respective anchor into a skeletal member so that an anchor-receiving hole is formed in the skeletal member. A plurality of second anchors also are provided, with each of the second anchors incorporating a proximal end, a distal end, a passage, and at least one hole.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.