Variable angle spinal fixation system

Surgery – Instruments – Orthopedic instrumentation

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C606S075000

Reexamination Certificate

active

06187005

ABSTRACT:

FIELD OF THE INVENTION
The present invention is directed to a spinal fixation system, and in particular one which includes a variable angle spinal fixation device.
BACKGROUND OF THE INVENTION
Stabilization of the spine is often required following trauma, tumor, or degenerative pathologies. Although each region of the spine presents unique clinical challenges, posterior fixation of the cervical spine is particularly troublesome. The anatomy of the cervical spine makes it a technically challenging area to instrument. Specifically, several vital neural and vascular structures including the vertebral arteries, nerve roots, and spinal cord must be avoided during surgery.
Current methods of posterior cervical stabilization include the use of metallic wire or cable and plate/screw systems. Both wire and plating systems suffer from limitations. For example, in certain clinical applications such as occipital-cervical and cervical-thoracic pathologies, the fixed location of the plate screw holes makes alignment of the screws difficult and may comprise the achieved stabilization.
In order to alleviate the problems associated with fixed screw hole location, devices allowing variability in screw placement are available. For example, U.S. Pat. No. 5,735,852 discloses a clamp that can be placed anywhere along the length of a rod. One problem with this and similar designs is that the clamp has a screw hole surface oriented at a fixed angle with respect to the rod. As a result, these systems often do not provide sufficient angulation of the screw to accommodate complex degenerative pathologies.
Variable angle screw systems are also currently available. U.S. Pat. No. 5,549,608 discloses a polyaxial locking screw and coupling element device for use with a rod fixation apparatus. Because the rod is located on top of the screw after the device is assembled, the device disclosed in the '608 patent has a high profile and does not allow independent screw and rod fixation. Without independent screw and rod fixation, some adjustability is lost along with the ability to compress or distract along the rod. Furthermore, should one of the components loosen, the entire construct also loosens. The osteosynthetic fixation device disclosed in U.S. Pat. No. 5,501,684 requires that the rod be threaded through a channel rather than simply slipping the rod through an opening on the side or top of the device. It should also be noted that the devices of the '684 and '608 patents were designed for use in the lumbar and sacral regions of the spine.
U.S. Pat. No. 5,643,259 discloses spine fixation instrumentation for the cervical spine. Because the instrumentation disclosed in the '259 patent relies on a sleeve mechanism to secure the rod and the screw to the connector, it is difficult to align both sleeves with the connector. Furthermore, when several connectors are used, alignment is even more difficult and unintended distraction between levels may occur when joining the rod sleeves to the connectors. Due to the limited space between adjacent vertebrae in the cervical region of the spine, there may not be sufficient room between connectors to allow placement of the sleeves. In addition, optimal orientation of the '259 patent system is limited by the inability to rotate the screw about an axis parallel to the rod, i.e. the system only provides for two degrees of freedom, possibly resulting in the need to bend the rod in order for it to fit within the connector. Since the system of the '259 patent depends on the ability to slide the sleeve mechanism along the rod when securing the rod to the connector, the fact that the rod may have to be bent to account for the missing third degree of freedom may prohibit the proper functioning of this sleeve mechanism, and the rod may not lock securely. Finally, the assembly and disassembly processes are tedious and require complicated instruments.
As the discussion above illustrates, there is a need for an improved fixation apparatus for stabilizing the cervical spine.
SUMMARY OF THE INVENTION
The spinal fixation system according to the present invention comprises a longitudinal member positionable along a spinal column; a fastener having a threaded end for engaging a vertebra; and a connector member for connecting the fastener and the longitudinal member. The connector member includes a channel extending through side surfaces of the connector member for receiving the longitudinal member; an opening laterally displaced from the channel and extending through top and bottom surfaces of the connector member for receiving the fastener; and a fastener clamping element for securing the fastener in the opening at a surgeon selected angle relative to the connector member and longitudinal member. Preferably, the system further comprises a longitudinal member clamping element for securing the longitudinal member in the channel.
In one embodiment, the channel has a substantially oval-shaped cross section to allow positioning of the longitudinal member in the channel at discrete locations. In another embodiment, the channel is open on top to allow insertion of the longitudinal member in the channel. Alternatively, the channel is open on a side to allow insertion of the longitudinal member in the channel.


REFERENCES:
patent: 4946458 (1990-08-01), Harms et al.
patent: 5047029 (1991-09-01), Aebi et al.
patent: 5207678 (1993-05-01), Harms et al.
patent: 5261909 (1993-11-01), Sutterlin et al.
patent: 5312404 (1994-05-01), Asher et al.
patent: 5312405 (1994-05-01), Korotko et al.
patent: 5352226 (1994-10-01), Lin
patent: 5466237 (1995-11-01), Byrd, III et al.
patent: 5474551 (1995-12-01), Finn et al.
patent: 5474555 (1995-12-01), Puno et al.
patent: 5499983 (1996-03-01), Hughes
patent: 5501684 (1996-03-01), Schlapfer et al.
patent: 5520690 (1996-05-01), Errico et al.
patent: 5527314 (1996-06-01), Brumfield et al.
patent: 5531746 (1996-07-01), Errico et al.
patent: 5549608 (1996-08-01), Errico et al.
patent: 5554157 (1996-09-01), Errico et al.
patent: 5575791 (1996-11-01), Lin
patent: 5575792 (1996-11-01), Errico et al.
patent: 5578033 (1996-11-01), Errico et al.
patent: 5584831 (1996-12-01), McKay
patent: 5584834 (1996-12-01), Errico et al.
patent: 5586984 (1996-12-01), Errico et al.
patent: 5591166 (1997-01-01), Bernhardt et al.
patent: 5607426 (1997-03-01), Ralph et al.
patent: 5609593 (1997-03-01), Errico et al.
patent: 5609594 (1997-03-01), Errico et al.
patent: 5613968 (1997-03-01), Lin
patent: 5643259 (1997-07-01), Sasso et al.
patent: 5647873 (1997-07-01), Errico et al.
patent: 5669911 (1997-09-01), Errico et al.
patent: 5672176 (1997-09-01), Biedermann et al.
patent: 5683392 (1997-11-01), Richelsoph et al.
patent: 5688273 (1997-11-01), Errico et al.
patent: 5690630 (1997-11-01), Errico et al.
patent: 5728098 (1998-03-01), Sherman et al.
patent: 5733285 (1998-03-01), Errico et al.
patent: 5735853 (1998-04-01), Olerud
patent: 5741255 (1998-04-01), Krag et al.
patent: 5752957 (1998-05-01), Ralph et al.
patent: 5776135 (1998-07-01), Errico et al.
patent: 5782831 (1998-07-01), Sherman et al.
patent: 5797911 (1998-08-01), Sherman et al.
patent: 5810819 (1998-09-01), Errico et al.
patent: 5817094 (1998-10-01), Errico et al.
patent: 5863293 (1999-01-01), Richelsoph
patent: 5879350 (1999-03-01), Sherman et al.
patent: 5938663 (1999-08-01), Petreto
patent: 5997539 (1999-12-01), Errico et al.
patent: 195 09 332 C1 (1996-08-01), None
patent: 0 330 881 A1 (1989-09-01), None
patent: 0 465 158 A2 (1992-01-01), None
patent: 2 759 894 (1998-08-01), None
patent: WO 94/00066 (1994-01-01), None
patent: WO 96/28104 (1996-09-01), None
patent: WO 98/34554 (1998-08-01), None

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Variable angle spinal fixation system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Variable angle spinal fixation system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable angle spinal fixation system will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2605911

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.