Surgery – Instruments – Orthopedic instrumentation
Patent
1999-04-21
2000-09-12
Buiz, Michael
Surgery
Instruments
Orthopedic instrumentation
606 72, A61B 1756
Patent
active
061171360
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a hook for implants for correcting and stabilizing the spinal column with a head that has a seat for a rod that can be inserted into and fixed on the head and with a rear arm hookable behind the bone.
BACKGROUND OF THE INVENTION
German 41 07 480 describes a pedicle screw which serves for anchoring implants in the spinal column to which end bores are formed in the pedicle of the vertebra in which the threaded shaft of a pedicle screw is threaded. This type of mounting of implants has shown itself effective in practice; however cases are known in which anatomical considerations exclude the use of a pedicle screw, for instance with anomalies or with such bone structures that do not allow the use of a screw.
It is known to use, as an alternative to a pedicle screw, hooks that are hung on the pedicle or on the lamina of the spinal column in order to effect a distraction or compression. Since the hooks are only secured at one arm, the result is in many cases an insecure mounting.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to provide a hook of the above-described type which has an improved hold on the column.
SUMMARY OF THE INVENTION
This object is achieved in the above-described hook in that two of the hooks are provided whose heads are releasably latched to each other and whose arms form when latched together a ring.
The invention has the advantage that the column is surrounded by the latched-together ring-forming arms of the two hooks like a clamp. Thus there is not just a one-sided mounting of one of the hooks on the column which can be undone by a corresponding one-sided force, but the column is surrounded so that pressure and tensile forces can be transmitted.
To form the latch connection a bore is formed in the head of the first hook in which a pin formed on the head of the second hook can engage.
It is particularly preferable when the pin has a barb that in latched condition engages an undercut of the head of the first hook. Such hooking together produces a secure connection of the first hook with the second hook so that an unintentional or accidental separation of the two hooks is impossible.
In order to facilitate an intentional disconnection of the first hook from the second hook the pin is split and is formed of two spring tongues on which the barb is formed. The two spring tongues can be deflected so that the barbs are freed of the undercut and the pin can be pulled out of the bore of the first hook so that an emplaced hook can be moved around before the implant is finally positioned.
According to an alternative embodiment the pin is seated in a bore of the head of the second hook and is secured there by a pin inserted in a transverse bore. In addition to manufacturing advantages this embodiment has the additional advantage that after the pin is inserted into the bore of the first hook after the pin is withdrawn from the transverse bore it is also possible to separate the first hook from the second hook by driving the pin in the insert direction further through the bore of the first hook.
A particularly advantageous embodiment of the invention is characterized in that the head has a bow part reaching over both sides of the seat for the rod and having lateral arm parts releasably held on the head, and that presettable retaining parts are provided on the head and/or on the bow engageable against the rod in the recess to secure it by means of the bow closed over the recess to prevent it from shifting longitudinally. As a result of this construction the hooks can be used in standard implants with the extra step of first fitting the spinal column with the hooks and only subsequently setting the rod in place which makes manipulating the implant substantially easier.
The invention is further described in the following with reference to the embodiments shown in the drawing; therein
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of first and second hooks before being joined together;
FIG. 2 is a top view of the stru
REFERENCES:
patent: 4611582 (1986-09-01), Duff
patent: 5395370 (1995-03-01), Muller et al.
patent: 5527314 (1996-06-01), Brumfield
patent: 5928231 (1999-07-01), Klein et al.
Buiz Michael
Ulrich GmbH & Co. KG
Woo Julian W.
LandOfFree
Hooks for implants to correct and stabilize the vertebral column does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hooks for implants to correct and stabilize the vertebral column, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hooks for implants to correct and stabilize the vertebral column will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-91708