Surgery – Instruments – Orthopedic instrumentation
Patent
1990-03-13
1992-03-03
Hafer, Robert A.
Surgery
Instruments
Orthopedic instrumentation
623 17, A61F 504
Patent
active
050928678
DESCRIPTION:
BRIEF SUMMARY
The invention refers to a correction and supporting apparatus as in particular used for the spinal column.
UNFALLCHIRURGIE, Vol. 12 (1986), pages 68-70 discloses the mechanical principle for the dorsal stabilisation of the pectoral and lumbar spinal column by means of a correction and supporting apparatus. The brochure "Fixateur Interne fur die Wirbelsaule, Original-Instrumente und--Implantate der Schweizerischen Arbeitsgemeinschaft fur Osteosynthesefragen-AO" discloses a fixateur interne or internal fixation device. This device comprises two pairs of so-called Schanz screws. A first pair thereof is screwed into the first vertebra through the arc roots (pediculus) on both sides and a second pair thereof is screwed into a second vertebra through the arc roots (pediculus) on both sides. The Schanz screws then have a shaft of a length of about 10 cm projecting from the vertebra. After mounting the four Schanz screws a partial reposition of the vertebra is already manually possible by means of the long projecting screw ends. Thereafter threaded rods are slipped onto respective two Schanz screws lying on the same side of the superposed vertebra. Thereupon the projecting free ends of the Schanz screws are again operated and the threaded rods are arrested. Finally those parts of the Schanz screws which project beyond the threaded rods are cut off. Thereafter the fixateur is covered with the muscles and the skin and the cut is closed. Whenever the surgeon will discover the next day that an adjustment of the angular position of the vertebra would be required, such an adjustment is no longer possible, because the projecting parts of the Schanz screws which are necessary for adjusting the angular position have already been removed. Moreover, the rotational flexibility of the apparatus is low.
The DE 36 39 810 A1 discloses an implant for correction and/or stabilization of the spinal column. The implant comprises screws having a threaded shaft part and a receiving part which is rigidly connected with the threaded shaft part and turned away therefrom. A respective pair of screws has the end thereof rigidly connected with a tie rod through the corresponding receiving part. Moreover, the pair of screws is additionally connected through a tension rod at a point in a distance from the connection between the receiving part and the tie rod. In order to allow an adjustment of the axial direction of the screws and the vertebra receiving the screws in a direction deviating from the parallel position, the connection between the tension rod and both screws is adjusted such that a flexion or bending strain is exerted onto the tie rod or the tension rod. This results in an uncontrollable material stress which may, in course of time, lead to a destruction of the tension rod and/or the tie rod. This may result in unpredictable problems in the interior of the body.
It is the object of the invention to provide a correction and supporting apparatus which allows the adjustment and the locking of the vertebra position in the sense of a longitudinal displacement and of an angular position (i.e. flexion of the spinal column forward or backward) without bending stress of the rods used therein. Such an adjustment and locking operation shall be facilitated as much as possible. A readjustment after the operation shall be possible. According to a further development a high stability with respect to the rotational movement exerted on the vertebrae and with respect to an axial load shall be obtained. Moreover, these aims shall be reached with an apparatus having a small front-to-back size.
These objects are achieved by means of a correction and supporting apparatus according to claim 1. Further embodiments of the invention are characterized in the dependent claims.
The screws to be used in the apparatus correspond to those described in the EP-0 242 708.
Further features and advantages of the invention will be apparent from a description of an embodiment in connection with the figures. In the figures:
FIG. 1 shows a side view of the correction and s
REFERENCES:
patent: 3865105 (1975-02-01), Lode
patent: 4289123 (1981-09-01), Dunn
patent: 4836196 (1989-06-01), Park et al.
patent: 4932975 (1990-06-01), Main et al.
Biedermann Lutz
Harms Jurgen
Brown Donald
Hafer Robert A.
Owens Kerry
LandOfFree
Correction and supporting apparatus, in particular for the spina does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Correction and supporting apparatus, in particular for the spina, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Correction and supporting apparatus, in particular for the spina will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-269328