Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
1999-11-08
2001-12-11
Mancene, Gene (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
Reexamination Certificate
active
06328739
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a spine fixation apparatus, and more particularly to an enhanced spine fixation apparatus having a compact mechanism adjustable in three dimensions and an enhanced combination.
2. Description of the Prior Art
A spine fixation apparatus is an internal fixation system for fixing at least two vertebrae of the spine for the benefit of promoting recovery of a damaged spine. The spine fixation apparatus is usually made of stainless or special material and is widely used in line with the progress and development of surgical procedures. However, there are still some drawbacks existing in the known various spine fixation apparatuses, such as inconvenience to adjust in an arbitrary direction, damage to soft tissue, and inconvenience to operate. Such drawbacks occur in the light of the fact that the components in a spine fixation apparatus should be properly adjusted so as to conform to the anatomical structure of a patient and to eliminate stress subjected therein. In addition, even if a spine fixation apparatus adjustable in many axes has been developed in the prior art, it includes lots of components and requires a complicated assembly procedure, which in turn places a heavy stress one the surgeon and surgical staff. Also, a long duration for surgery may be required and thus patient morbidity resulting from blood loss and stress of anesthesia may increase.
In U.S. Pat. No. 5,474,551, a spinal fixation device which allows for adjustment in four axes with respect to an attachment of a longitudinal rod to vertebrae of a spinal column is disclosed. However, such a device consists of a multitudes of complicated components and tends to loosen. Moreover, a helical thread is provided on the exterior surface of a distal end of a pedicel screw for coupling other components, such as nut, and thus damage to soft tissue is possible due to exposure of threads after assembly. In U.S. Pat. No. 5,545,163, a spine fixation system comprising an elongated fixation plate is disclosed, in which the position of the plate to be fixed can be selected according to pitches of the pedicel screws. However, the range to be selected is segmental and the orientation of the spine fixation system is not able to be adjusted sufficiently. Further, a helical thread is also provided on the exterior surface of the distal end of a pedicel screw and thus soft tissue damage after assembly is also possible. In U.S. Pat. No. 5,261,910, a pedicel screw provided with a threaded hole at its distal end to couple with a screw is disclosed. However, such a construction fails to allow for an adjustment corresponding to the distance of two pedicel screws and the oblique angles of pedicel screws implanted into the vertebrae. In U.S. Pat. No. 5,735,850, a fastening system for pedicel screws each having a threaded hole at its distal end is disclosed, in which the angle of a connecting member relative to each pedicel screw can be adjusted by the provision of a counter-part capable of sliding against the surface of the connecting member. However, the fixed points of said connecting member cannot be freely selected in so far as to conform to the pitch of two pedicel screws.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an enhanced spine fixation apparatus capable of inclusively overcoming the above drawbacks, which is conveniently installed, easily adjusted for compensating implanting deviation of pedicel screws, and able to avoid damage to soft tissue.
Another object of the present invention is to provide a spine fixation apparatus having a more stable coupling between components thereof.
In order to achieve the above objects, an enhanced spine fixation apparatus according to this invention comprising:
a connecting rod;
a plurality of coupling blocks each having a lower side surface and an upper side surface;
a plurality of pedicel screws each being anchorable in a vertebra;
a plurality of first securing elements each for securing the coupling blocks on the pedicel screws respectively;
a plurality of second securing elements each for securing the connecting rod on each of the coupling blocks; and
a plurality of third securing elements each having an engaging end surface for engaging with each of the first securing elements;
wherein, each of the pedicel screws includes a first head portion having a first spherical convex surface at a top end surface thereof, and a first engaging hole longitudinally extending substantially along a longitudinal axis of each of the screws and opening to the first convex surface;
each of the first securing elements includes:
a shank portion to be detachably secured in the first engaging hole of the pedicel screw; and
a second head portion having a second spherical convex surface disposed at a top of the shank portion; and
each of the coupling blocks includes:
a first socket for the shank portion of the first securing element passing therethrough, in which the first socket includes a first recess opening to the lower side surface and defined by a first concave surface for accommodating and matching with at least a portion of the first head portion, a second recess opening toward the upper side surface and defined by a second concave surface for accommodating and matching with the second head portion with a spacing left between portions of the second spherical convex surface and the second concave surface, and an aperture extending between and opening to the bottoms of the first and the second recesses and having a diameter larger than that of the shank portion and smaller than a largest diameter at either of the first and the second head portions;
a second socket substantially axially perpendicular to the first socket, for the connecting rod accommodated therein;
a second engaging hole substantially axially perpendicular to the second socket for securing the connecting rod in cooperation with the second securing element; and
a third engaging hole communicating with the second recess and opening to the upper side surface of the coupling block for engaging with the third securing elements so that the engaging end surface of the third securing element forces the first securing element against the coupling block.
According to the above structure, users could install in sequence each component of the spine fixation apparatus on the spine with a driving force in a direction coming down from the upside over a spine. Moreover, the vertical tilt angle of each coupling block relative to each pedicel screw can be moderately adjusted and the horizontal rotating angle thereof can be arbitrarily adjusted, and thus an adjustment of each coupling block relative to each pedicel screw in three dimensions is available. Accordingly, even if the implanting angle of the pedicel screw has little deviation, it could be easily compensated by the adjustment of the inclination and rotation of the coupling block relative to the pedicel screw. Furthermore, since an engaging hole is used by the pedicel screw to receive the distal end of the first securing element, soft tissue probably would not be damaged. And, by means of the provision of the third securing elements and the third engaging holes, the first securing elements could be more stably retained in the pedicel screws and thereby firmly secure the coupling blocks. Therefore, it is possible to obtain an enhanced spine fixation apparatus which is simply constructed, conveniently operated, easily adjusted, and firmly assembled, as well as being non damaging to soft tissue.
These and the other objects, characteristics and effects of this invention will become clearer based upon the following detailed description with regard to this invention.
REFERENCES:
patent: 5047029 (1991-09-01), Aebi et al.
patent: 5053034 (1991-10-01), Olerud
patent: 5129900 (1992-07-01), Asher et al.
patent: 5261910 (1993-11-01), Warden et al.
patent: 5403314 (1995-04-01), Currier
patent: 5474551 (1995-12-01), Finn et al.
patent: 5487744 (1996-01-01), Howland
patent: 5545163 (1996-08-01), Miller
Choeo Audy
Jang Ben-Hwa
Jao Wei-Tai
Liu Chien-Lin
Shaio Chen-Dao
Industrial Technology Research Institute
Ladas & Parry
Mancene Gene
Robert Eduardo C.
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