Surgery – Truss – Pad
Patent
1983-11-03
1986-02-25
Cohen, Lee S.
Surgery
Truss
Pad
128303R, A61B 500
Patent
active
045722129
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention is concerned with the measurement of intracranial pressure. Several devices have been utilized to perform such measurements. These include intraventricular catheters, subarachnoid bolts and solid state or implantable transducers. This invention relates to improvements in subarachnoid bolts.
BACKGROUND ART
Subarachnoid bolts for measuring or monitoring intracranial pressure have been known for some time. One of the more widely utilized bolts, commonly referred to as a "Philly" bolt, is comprised essentially of stainless steel or similar material and includes an external screw thread at its lower end which is intended to be screwed into a twist drill hole formed in a patient's skull. The extreme end of the bolt enters the subarachnoid space over the cerebral hemisphere.
While known subarachnoid bolts have met with some success, they have also suffered from many problems particularly with patients with very thin skulls such as neonatal patients. With such patients and in many other cases, it is extremely difficult and sometimes impossible to secure the bolt to the skull by screwing the same thereto.
DISCLOSURE OF INVENTION
The present invention overcomes the defects of the prior art known to Applicant and provides a subarachnoid bolt which can be easily secured to substantially any skull. The bolt of the present invention includes a lower bolt half and an upper bolt half which can be screwed to the lower bolt half. A tubular member extends downwardly from the lower bolt half and is adapted to be inserted into a hole formed in a patient's skull. In one embodiment, the bolt is securely held in place when the free end of a tubular element carried by the upper bolt half enters the tubular member and cams the lowermost end thereof radially outwardly when the two bolt halves are screwed together. In a second embodiment, a sleeve on the lower bolt half bulges outwardly against the walls of the hole when the two bolt halves are screwed together.
BRIEF DESCRIPTION OF DRAWINGS
For the purpose of illustrating the invention, there are shown in the accompanying drawings forms which are presently preferred; it being understood that the invention is not intended to be limited to the precise arrangements and instrumentalities shown.
FIG. 1 is a perspective view of a subarachnoid bolt constructed in accordance with the principles of the present invention;
FIG. 2 is an exploded perspective view of the bolt shown in FIG. 1;
FIG. 3 is a cross-sectional view of the lower bolt half inserted in a hole in a patient's skull;
FIG. 4 is a cross-sectional view of the bolt secured to a patient's skull;
FIG. 5 is a perspective view of a second embodiment of a subarachnoid bolt according to the invention;
FIG. 6 is an exploded perspective view of the bolt shown in FIG. 5;
FIG. 7 is a cross-sectional view of the lower half of the bolt of FIG. 5 inserted in a hole in a patient's skull, and
FIG. 8 is a cross-sectional view of the bolt of FIG. 5 secured to a patient's skull.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring now to the drawings in detail wherein like reference numerals have been used throughout the various figures to designate like elements, there is shown in FIG. 1 a first embodiment of subarachnoid bolt constructed in accordance with the principles of the present invention and designated generally as 10. In FIG. 1, bolt 10 is shown secured to the skull 12 of a patient.
Bolt 10 is comprised of two parts: a lower bolt half 14 and an upper bolt half 16. As shown most clearly in FIGS. 2 and 3, lower bolt half 14 is essentially circular in cross section except for the upper portion thereof which is squared as shown at 18 to form a means by which a wrench or similar tool can hold the lower bolt half 14 to prevent the same from rotating. The reason for this will become more readily apparent hereinafter.
The lower section of lower bolt half 14 is reduced in diamter and forms a tubular member 20 which is coaxially aligned with the remaining parts of the bolt. An enlarged flange 22 is
REFERENCES:
patent: 4062354 (1977-12-01), Taylor et al.
patent: 4186728 (1980-02-01), van Lofringen
Cohen Lee S.
Sweeney, Jr. Paul L.
Sykes Angela D.
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