Surgery – Instruments – Means for inserting or removing conduit within body
Reexamination Certificate
2001-02-12
2003-09-23
Robert, Eduardo C. (Department: 3732)
Surgery
Instruments
Means for inserting or removing conduit within body
Reexamination Certificate
active
06623490
ABSTRACT:
TECHNICAL FIELD
This invention relates to cranial bolts or screws and systems for monitoring physiological functions in human and animal brains.
BACKGROUND
Cranial bolts are frequently used for temporarily securing a catheter to the skull, the catheter being used for monitoring intercranial pressure in the intensive care of patients who have suffered head injuries. In one procedure a catheter is introduced into the brain through a hollow bolt and the intercranial pressure measured by means of a sensor in the tip of the catheter. The catheter may be inserted into various parts of the brain. Where it is introduced into a cranial ventricle, the catheter may also be used to draw off cerebral spinal fluid (CSF) in order to alleviate pressure increases or to analyse samples of the CSF.
Existing cranial bolts are bulky and typically incorporate a Luer lock or other device for fixing the catheter securely to the bolt.
More recently interest has arisen in measuring a number of physiological parameters in the brain during intensive care. If a number of securing devices, such as Luer locks are incorporated in the bolt, it becomes even more bulky and awkward to use.
SUMMARY
It is now proposed to provide a cranial bolt in which one or more tubes (or a single multi-lumen catheter) are fixed directly into a hollow shank forming the body of the bolt and individual passageways are provided within the shank for passing probe(s) or tube(s) into desired positions in the brain.
According to one aspect of the invention there is provided a cranial bolt for connecting one or more elongate, flexible members, such as tubes, cables, filaments or the like, with the interior of the skull, said bolt comprising a hollow shank having one threaded end and a second end opposite said threaded end for receiving one or more elongate members, each said member being retained in said second end and communicating with a separate passageway in the shank extending to the threaded end.
Conveniently the tube or tubes or other elongate member are fixed into the end of the shank with adhesive.
It will be appreciated that instead of fixing a plurality of individual catheters into the second open end of the shank, a multi-lumen catheter could be fixed into the end of the shank and probes or smaller tubes fed through respective lumens and passageways into the brain. The term ‘multi-lumen catheter’ is used here in a broad sense and may comprise a bundle of individual tubes which are gathered together, e.g. by enclosing them in a common external sheath, or held together by a non-tubular gathering device such as a series of external rings or a spring-like coil. Alternatively, the multi-lumen catheter may be a catheter in which two or more lumens are extruded integrally so that externally the catheter appears to be a single tube. Whatever the particular construction selected, the individual lumens are split out of the assembly at the point where the catheter enters the shank and individual connections are made to passageways therein. Similarly, at the end of the assembly remote from the shank, the lumens are split out of the assembly and individual connections made to appropriate devices, e.g. via Luer locks.
Although the shank may be manufactured from plastics material, e.g. an engineering plastic such as polycarbonate, the shank is preferably made from metal. Some plastics are hard enough to cut a thread in the skull but metals do this more efficiently. Titanium or its alloys are preferred because they are non-magnetic and interfere less than other materials in magnetic scanning procedures. The bolts of the present invention are designed to make use of the minimum of metal.
In order to facilitate manipulation of the bolt and manually screwing the bolt into the skull while minimising the amount of metal employed in manufacturing the bolt, a metal shank is preferably received within a plastics body member which may be moulded with wings or other projections to permit the member to be gripped and the shank screwed more easily into a hole in the skull.
Preferably the shank is generally cylindrical and preferably formed with a central axial passageway and a further passageway or passageways disposed around the central passageway. The central passage preferably has a larger cross-section than the further passageways and may be used for example, for draining CSF fluid. The further passageways are preferably angled with respect to the central passageway. For example, they may be inclined at an angle between about 3 and 15° (such as about 5 to 10°) to the longitudinal axis of the shank.
In order to avoid the danger of the catheters kinking, particularly at or close to the point where they enter the shank, a kink-resistant catheter construction is preferred. Flexible tubes can be made kink-resistant by stiffening them with a spring
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, such as a coil spring. The spring may be metal or plastic but preferably is a tubular metal coil spring, and the wire from which it is made preferably has a generally flat cross-section. In order to minimise flow disturbance or contamination of fluids in the tube, the spring is preferably embedded or encapsulated in the wall of the tube or is sandwiched between coaxial tubes which form the catheter. Catheters such as described in U.S. Pat. Nos. 5380304 and 5700253 and in our U.S. patent application Ser. No. 09/093,934 are preferred, and their disclosure is specifically incorporated herein by reference.
REFERENCES:
patent: 4629451 (1986-12-01), Winters et al.
patent: 4903707 (1990-02-01), Knute et al.
patent: 5054497 (1991-10-01), Kapp et al.
patent: 5246441 (1993-09-01), Ross et al.
patent: 5545179 (1996-08-01), Williamson, IV
patent: 5634911 (1997-06-01), Hermann et al.
patent: 6152933 (2000-11-01), Werp et al.
patent: 298 17 986 (1999-02-01), None
patent: 198 20 808 (1999-11-01), None
patent: 96/22798 (1996-08-01), None
Crane Barry C.
Irvine Michael P.
Markle David R.
Diametrics Medical Limited
Merchant & Gould P.C.
Robert Eduardo C.
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