Surgery – Truss – Perineal
Patent
1980-05-09
1984-01-03
Rosenbaum, C. Fred
Surgery
Truss
Perineal
128 92R, 145 305, A61F 504
Patent
active
044237219
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a metallic device for the insertion and extraction of medullary nails the device consisting of a guide tube, striking devices on both ends, and a strike bushing.
It is known practice to drive a medullary nail into the predrilled medullary cavity by means of a striker formed like a chisel and with a hammer. To guide the nail, a guide spit is driven into the medullary cavity as the medullary canal is being bored. For extraction, a nail catcher is used which has a hook on one side that is hooked into a slit type opening in the nail. The end on the other side of the nail catcher is bent and forms an abutment, which is struck by a specially formed hammer which can be moved parallel to the nail catcher.
It is also known in some forms of nails to screw in the nail catcher in a threaded opening in the nails.
These known tools present problems such as optimum transmission of force in the axial direction of the nail and the possibility of injury due to slipping of the hammer or the striker.
From DT-GM No. 75 18 496 and DT-GM S No. 48 682 there are known knock-out devices consisting of a guide rod provided with a knock-out bushing that is displaceable concentrically with respect to the rod and a striking device at the end farthest from the medullary nail. In one embodiment, the guide rod is screwed to the medullary nail. In the other embodiment, it is clamped to the nail by means of a slotted sleeve and a wedge. These devices exhibit disadvantages since their usefulness is for the knocking out of a medullary nail, and as well, they employ an unwieldy strike bushing, since the latter is made of steel and it must be of a very large size to obtain the necessary extraction force.
In contradistinction, it is the object of the present invention to provide a device for the insertion and extraction of medullary nails which consists of a guide tube, striking devices on both ends of the tube, and a strike bushing, which does not have the mentioned disadvantages.
This problem is solved according to the invention by providing a guide tube that is recessed that is provided with two successive longitudinal section, the tube diameters diminishing at the transitions or junctures between the individual longitudinal sections and the portion of the inner longitudinal section towards the medullary nail being threaded. Further the striking device provided on this end is an insertion sleeve which is displaceably disposed on the inner longitudinal tube section being concentrically and slidably disposed thereon and having on the end towards the strike bushing a thickened portion in the form of a truncated cone. Moreover the strike bushing is made of heavy metal or alternatively of heavy metal powder surrounded by a steel jacket and the two striking devices are removable from the guide tube.
The removable striking device at the end of the guide tube farthest from the medullary nail is a three-piece construction. A two-piece sleeve, which has a larger outside diameter than the guide tube, is placed on a longitudinal section of the guide tube which is recessed to a smaller diameter and is held by a clamping sleeve which is fitted on therein.
The outer offset longitudinal section of the guide tube, whose diameter is slightly smaller than the core diameter of the thread of the inner longitudinal section, results in proper guiding when the guide tube is being screwed into the meduallary nail.
A circlip in the interior of the insertion sleeve and a spring tongue provided on the clamping sleeve prevent these parts from falling down when the tool is being handled.
An embodiment of the invention is described below with reference to the figures.
FIG. 1 is an elevational view of the assembled tool;
FIG. 2 is a sectional view through the end of the guide tube farthest from the medullary nail and through the striking device.
Referring to FIG. 1 there is shown there guide tube 1, whose inside diameter is dimensional so that together with the screwed-on medullary nail it can be displaced over the guide spit, be driven into the bone
REFERENCES:
patent: 462252 (1891-11-01), Gillette
patent: 1747053 (1930-02-01), Colerick
patent: 3036482 (1962-05-01), Kenworthy et al.
patent: 3208450 (1965-09-01), Abelson
Zimmer Mfg. Co., Catalog published 1953, vol. 35-A, p. 17, see item #460.
Richards Mfg. Co., Catalog published 1974, p. 72, see item 11-1119S.
Otte Heinz
Otte Wolf-Dieter
Schider Siegfried
Wiesner Otto
Rosenbaum C. Fred
Schwarzkopf Development Corporation
Shedd C. W.
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