This invention relates generally to bone anchoring and, in particular, to a low-profile anchor system, particularly suited to pelvis fixation.
Scoliosis is a condition that affects many children, teenagers, and adults. Broadly speaking, scoliosis is a condition whereby the human spine departs from its natural curvatures which help the body to move and remain flexible. There are several “warning signs” to determine if someone has scoliosis, including shoulders at different heights; one shoulder blade more prominent than the other; the appearance of a prominent hip; leaning of the entire body to one side; and other physical signs.
There are various treatment options for scoliosis, both non-surgical and surgical. Surgery is an option used primary for several scoliosis (i.e., curves greater than 45°, or for curves that do not respond to bracing.
The need remains, however, for improved techniques that provide stabilization, preferably without pronounced evidence of instrumentation. Such techniques may be particularly adaptable to neuromuscular scoliosis (cerebral palsy) requiring corrective rod fixation and stabilization to the pelvis in children/young adults with significant deformity and poor muscle mass protection.
This invention improves upon the prior art by providing a low-profile bone anchoring system particularly suited to pelvis fixation in conjunction with spinal correction. The preferred embodiment utilizes screw fixation, followed by deployment of penetrating anchoring arms, expansion of outer sleeve, or both.
The proximal ends of the screw anchors are preferably flush or deep to the bone surface. An internal screw mechanism is utilized to deploy side anchoring arms, or expansion of outer sleeve, or both. Serrated top edge interfaces with low profile variable axis/angled elbow (VAE), which has varying lengths/dimensions to accommodate anatomy and differing rod sizes.
The VAEs preferably feature a serrated bottom edge to interface with anchor screw. Locking screw at elbow secures into inner threads of pelvis anchor screw. Each VAE captures a rod, end to end, or by passing rod through the side of elbow. Small locking screws secure rod to elbow.
This invention is directed to a low-profile screw anchor system, facilitating variable axis and angle fixation to the pelvis, particularly for corrective rod fixation and stabilization of the type used to correct deformities, such as scoliosis. The invention covers different aspects, including implants and instrumentation. In terms of implants, the invention provides for an in-situ deployable pelvis screw anchor, and different styles of variable-axis elbows that connect the anchors to a rod system. In terms of instrumentation, an inventive inner core screw driver is used.
The inner core screw plug 106 is, in turn, coupled to one or more deployable side anchors 110, which emerge from the sides of the device during deployment, as best seen in
The body of the device of
The anchor of
As an alternative to the penetrating side anchors discussed with reference to
Once a pelvis screw anchor according to the invention is in place, a device used to couple the screw anchor to a rod system is attached between the anchor and associated rod.
This application claims priority from U.S. Provisional Patent Application Ser. No. 60/456,866, filed Mar. 24, 2003, the entire content of which is incorporated herein by reference.
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Number | Date | Country | |
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20040193157 A1 | Sep 2004 | US |
Number | Date | Country | |
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60456866 | Mar 2003 | US |