U.S. patent application number 14/148206 was filed with the patent office on 2014-11-06 for composite skull pins with reduced x-ray signature.
This patent application is currently assigned to NeuroLogica Corp.. The applicant listed for this patent is NeuroLogica Corp.. Invention is credited to Eric Bailey, Matthew Dickman, Andrew Tybinkowski.
Application Number | 20140328470 14/148206 |
Document ID | / |
Family ID | 41201769 |
Filed Date | 2014-11-06 |
United States Patent
Application |
20140328470 |
Kind Code |
A1 |
Bailey; Eric ; et
al. |
November 6, 2014 |
COMPOSITE SKULL PINS WITH REDUCED X-RAY SIGNATURE
Abstract
A composite skull pin comprising: a core comprising a cone
terminating in a distal point, the core being formed out of a
substantially radiotranslucent material; and a jacket comprising a
hollow cone terminating in a sharp distal point, the hollow cone of
the jacket being sized and shaped so that it overlies, and closely
conforms to, the exterior of the cone of the core, the jacket being
formed out of a strong, hard material, and further wherein the
jacket has a sufficiently small mass such that the composite skull
pin has a low X-ray signature.
Inventors: |
Bailey; Eric; (North
Hampton, NH) ; Tybinkowski; Andrew; (Boxford, MA)
; Dickman; Matthew; (Chelsea, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NeuroLogica Corp. |
Danvers |
MA |
US |
|
|
Assignee: |
NeuroLogica Corp.
Danvers
MA
|
Family ID: |
41201769 |
Appl. No.: |
14/148206 |
Filed: |
January 6, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12403247 |
Mar 12, 2009 |
8623029 |
|
|
14148206 |
|
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61069104 |
Mar 12, 2008 |
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Current U.S.
Class: |
378/208 |
Current CPC
Class: |
A61B 2017/00964
20130101; A61B 17/00 20130101; A61B 90/14 20160201; A61B 2017/00915
20130101; A61B 2017/0092 20130101; A61B 6/04 20130101 |
Class at
Publication: |
378/208 |
International
Class: |
A61B 6/04 20060101
A61B006/04; A61B 17/00 20060101 A61B017/00 |
Claims
1. A composite skull pin comprising: a core comprising a cone
terminating in a distal point, the core being formed out of a
substantially radiotranslucent material; and a jacket comprising a
hollow cone terminating in a sharp distal point, the hollow cone of
the jacket being sized and shaped so that it overlies, and closely
conforms to, the exterior of the cone of the core, the jacket being
formed out of a strong, hard material, and further wherein the
jacket has a sufficiently small mass such that the composite skull
pin has a low X-ray signature.
2. A composite skull pin according to claim 1 wherein the core is
formed out of carbon graphite.
3. A composite skull pin according to claim 1 wherein the jacket is
formed out of a non-radiotranslucent material.
4. A composite skull pin according to claim 1 wherein the jacket is
formed out of titanium.
5. A composite skull pin according to claim 1 wherein the jacket is
formed out of a synthetic plastic material of the type marketed by
Integra LifeSciences Corporation of Plainsboro, N.J. under the
trade name Sapphire.TM..
6. A composite skull pin according to claim 1 wherein the jacket
has a thickness of about 0.010 inches or less.
7. A composite skull pin according to claim 1 wherein the core
comprises a cylindrical body having the cone on its distal end and
a cylinder on its proximal end, with a first annular shoulder being
formed at the intersection of cylindrical body and the cone, and a
second annular shoulder being formed at the intersection of
cylindrical body and the cylinder.
8. A composite skull pin according to claim 7 wherein the base of
the jacket engages the first annular shoulder of the core.
9. A composite skull pin according to claim 7 wherein the core
comprises a cylindrical body, wherein the core is mounted to the
core by a cylinder, and further wherein the base of the jacket
engages portions of the cylinder.
10. A method for scanning the head of a patient, comprising:
providing a head frame which is at least partially
radiotranslucent, and providing a composite skull pin, where the
composite skull pin comprises: a core comprising a cone terminating
in a distal point, the core being formed out of a substantially
radiotranslucent material; and a jacket comprising a hollow cone
terminating in a sharp distal point, the hollow cone of the jacket
being sized and shaped so that it overlies, and closely conforms
to, the exterior of the cone of the core, the jacket being formed
out of a strong, hard material, and further wherein the jacket has
a sufficiently small mass such that the composite skull pin has a
low X-ray signature; and securing the head of a patient to the head
frame using the composite skull pin.
11. A method according to claim 10 wherein the core is formed out
of carbon graphite.
12. A method according to claim 10 wherein the jacket is formed out
of a non-radiotranslucent material.
13. A method according to claim 10 wherein the jacket is formed out
of titanium.
14. A method according to claim 10 wherein the jacket is formed out
of a synthetic plastic material of the type marketed by Integra
LifeSciences Corporation of Plainsboro, N.J. under the trade name
Sapphire.TM..
15. A method according to claim 10 wherein the jacket has a
thickness of about 0.010 inches or less.
16. A method according to claim 10 wherein the core comprises a
cylindrical body having the cone on its distal end and a cylinder
on its proximal end, with a first annular shoulder being formed at
the intersection of cylindrical body and the cone, and a second
annular shoulder being formed at the intersection of cylindrical
body and the cylinder.
17. A method according to claim 16 wherein the base of the jacket
engages the first annular shoulder of the core.
18. A method according to claim 16 wherein the core comprises a
cylindrical body, wherein the core is mounted to the core by a
cylinder, and further wherein the base of the jacket engages
portions of the cylinder.
Description
REFERENCE TO PENDING PRIOR PATENT APPLICATION
[0001] This patent application claims benefit of pending prior U.S.
Provisional Patent Application Ser. No. 61/069,104, filed Mar. 12,
2008 by Eric Bailey et al. for SKULL PINS WITH REDUCED X-RAY
SIGNATURE (Attorney's Docket No. NEUROLOGICA-24 PROV), which patent
application is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to surgical procedures in general,
and more particularly to intracranial surgical procedures.
BACKGROUND OF THE INVENTION
[0003] In many situations it may be necessary to perform an
intracranial surgical procedure. By way of example but not
limitation, a patient may have suffered a large hemorrhagic stroke
and may require accumulated blood to be removed from the interior
of the skull so as to relieve pressure on the brain. Or the patient
may have developed a tumor which requires removal. Or the patient
may have suffered a cerebral injury which requires surgical
intervention.
[0004] Regardless of the patient's underlying condition and the
specific surgical procedure which is to be performed, intracranial
surgical procedures typically share a number of common aspects.
[0005] For one thing, due to the anatomy involved, intracranial
surgical procedures generally require opening the skull at one or
more locations, and then accessing specific sites within the
interior of the skull in order to effect a desired surgical
procedure.
[0006] Furthermore, in view of the delicate neurological tissues
present in this region of the body, it is often necessary to
stabilize the patient's head with some sort of external framework
during the surgical procedure. This external framework generally
comprises a multi-dimensional frame which is positioned alongside
different surfaces of the head, and a plurality of skull pins which
extend from the frame into engagement with the skull. By providing
the skull pins with sharp distal tips, and by configuring the frame
so that the skull pins are directed into the skull from a variety
of different angles, the skull can be stabilized during the
surgical procedure. See, for example, FIG. 1, which shows a head
frame (formed out of stainless steel) offered by Pro Med
Instruments GmbH of Freiburg, Germany under the trade name
DORO.TM., and FIG. 2, which shows a skull pin (formed out of a
stainless steel pin with a plastic mount) offered by Pro Med
Instruments GmbH under the trade name DORO.TM..
[0007] Additionally, since direct visualization is, at best,
generally quite limited within the intracranial spaces (e.g., due
to the surrounding portions of the skull and, in many cases, the
presence of intervening neurological tissues), it is frequently
necessary (or, at the very least, highly desirable) to utilize
scanners (e.g., X-ray devices, MRI machines, ultrasound imagers,
etc.) before, during and after the surgical procedure. Such
scanners permit visualization of internal tissue structures even
where direct visualization is not possible. In this respect it
should be appreciated that the use of such scanners prior to,
during and immediately following the surgical procedure can be
extremely important in intracranial surgery, due to the restricted
fields of view, delicate neurological tissues and navigation
requirements. This is particularly true during the intracranial
procedure itself. In this respect it should also be appreciated
that X-ray devices (e.g., CT machines, C-arm fluoroscopes, etc.)
are generally the most desirable type of scanner for use during
intracranial surgery, due to the high quality of their images, the
ready availability of such devices within the operating suite, etc.
MRI scanners are generally not preferred for intraoperative use for
a variety of reasons, including the need to remove metal objects
from the region of the scanner, etc.
[0008] Unfortunately, the need to use these X-ray devices during
surgery complicates the design of the aforementioned head frame and
skull pins. This is because forming the head frame and skull pins
out of stainless steel (the traditional material of choice for
operating room frames) dramatically undermines the quality of the
X-ray image due to the enormous X-ray signature of stainless steel.
See, for example, FIG. 3, which shows a typical X-ray image where
no head frame and skull pins are present. Where the head frame and
skull pins are formed out of stainless steel, large sections of the
X-ray image (i.e., those sections which are aligned with the head
frame and/or skull pins) are obscured and hence effectively
unusable.
[0009] In view of the foregoing, attempts have been made to
fabricate the head frame and skull pins out of radiotranslucent
materials. Thus, and looking now at FIG. 4, there is shown another
system offered by Pro Med Instruments GmbH of Freiburg, Germany
under the trade name DORO.TM., wherein the head frame is made out
carbon graphite (a material which is substantially
radiotranslucent) and only the skull pins are made out of stainless
steel. As can be seen in FIG. 5, this approach significantly
improves the quality of the X-ray images. However, the presence of
the stainless steel skull pins in the X-ray field still creates a
significant loss of image.
[0010] To this end, attempts have been made to fabricate the skull
pins out of radiotranslucent materials. Unfortunately, carbon
graphite (the material used to fabricate the radiotranslucent head
frame) does not provide a satisfactory skull pin, since carbon
graphite is too brittle to form the strong, sharp distal tips
needed to penetrate into the skull. Attempts to use other
radiotranslucent materials (e.g., various plastics) have also
proven to be unsatisfactory. As a result, skull pins are frequently
formed out of metals (e.g., titanium) which have an X-ray signature
which is lower than the X-ray signature of stainless steel. While
forming skull pins out of titanium generally results in X-ray
images superior to the images formed when using skull pins formed
out of stainless steel, there is still substantial image loss due
to the X-ray signature of the titanium skull pins. See FIG. 6.
[0011] There is, therefore, a substantial need for a new approach
for forming skull pins which have all of the strength and integrity
needed to effectively penetrate and grip the skull, yet which have
a sufficiently small X-ray signature so as to permit the creation
of X-ray images of high quality.
SUMMARY OF THE INVENTION
[0012] The present invention provides a novel composite skull pin
having all of the strength and structural integrity needed to
effectively penetrate and grip the skull, yet which also provides a
reduced X-ray signature so as to permit the creation of X-ray
images of superior quality.
[0013] In one form of the invention, there is provided a composite
skull pin comprising:
[0014] a core comprising a cone terminating in a distal point, the
core being formed out of a substantially radiotranslucent material;
and
[0015] a jacket comprising a hollow cone terminating in a sharp
distal point, the hollow cone of the jacket being sized and shaped
so that it overlies, and closely conforms to, the exterior of the
cone of the core, the jacket being formed out of a strong, hard
material, and further wherein the jacket has a sufficiently small
mass such that the composite skull pin has a low X-ray
signature.
[0016] In another form of the invention, there is provided a method
for scanning the head of a patient, comprising:
[0017] providing a head frame which is at least partially
radiotranslucent, and providing a composite skull pin, where the
composite skull pin comprises: [0018] a core comprising a cone
terminating in a distal point, the core being formed out of a
substantially radiotranslucent material; and [0019] a jacket
comprising a hollow cone terminating in a sharp distal point, the
hollow cone of the jacket being sized and shaped so that it
overlies, and closely conforms to, the exterior of the cone of the
core, the jacket being formed out of a strong, hard material, and
further wherein the jacket has a sufficiently small mass such that
the composite skull pin has a low X-ray signature; and
[0020] securing the head of a patient to the head frame using the
composite skull pin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] These and other objects and features of the present
invention will be more fully disclosed or rendered obvious by the
following detailed description of the preferred embodiments of the
invention, which is to be considered together with the accompanying
drawings wherein like numbers refer to like parts, and further
wherein:
[0022] FIG. 1 is a schematic view showing a prior art stainless
steel head frame;
[0023] FIG. 2 is a schematic view showing a prior art skull pin
comprising a stainless steel pin with a plastic mount;
[0024] FIG. 3 is a schematic view showing a typical X-ray image
where no head frame and skull pins are present;
[0025] FIG. 4 is a schematic view showing a prior art system
comprising a radiotranslucent head frame and stainless steel skull
pins;
[0026] FIG. 5 is a schematic view showing a typical X-ray image
where the head frame is formed out of a radiotranslucent material
and the skull pins are formed out of stainless steel;
[0027] FIG. 6 is a schematic view showing a typical X-ray image
where the head frame is formed out of a radiotranslucent material
and the skull pins are formed out of titanium;
[0028] FIG. 7 is an exploded schematic view showing a novel
composite skull pin formed in accordance with the present
invention;
[0029] FIG. 8 is a schematic side view showing the radiotranslucent
carbon graphite core of the composite skull pin shown in FIG.
7;
[0030] FIG. 9 is a schematic distal end view of the
radiotranslucent carbon graphite core shown in FIG. 8;
[0031] FIG. 10 is a schematic proximal end view of the
radiotranslucent carbon graphite core shown in FIG. 8;
[0032] FIG. 11 is a schematic view showing the titanium jacket of
the composite skull pin shown in FIG. 7;
[0033] FIG. 12 is a schematic sectional view of the titanium jacket
shown in FIG. 11;
[0034] FIG. 13 is a schematic view showing a typical X-ray image
where the head frame is formed out of a radiotranslucent material
and the skull pins are formed with the composite construction shown
in FIG. 7;
[0035] FIG. 14 is an exploded schematic view showing an alternative
form of composite skull pin formed in accordance with the present
invention;
[0036] FIG. 15 is a schematic side view showing the composite skull
pin shown in FIG. 14;
[0037] FIG. 16 is a schematic distal end view of the composite
skull pin shown in FIG. 14;
[0038] FIG. 17 is a schematic proximal end view of the composite
skull pin shown in FIG. 14; and
[0039] FIG. 18 is a schematic sectional view, taken along line
18-18 of FIG. 17, showing the composite skull pin shown in FIG.
14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] Looking now at FIGS. 7-12, there is shown a novel composite
skull pin 5 formed in accordance with the present invention.
Composite skull pin 5 generally comprises a carbon graphite core 10
carrying, over a selected portion of its exterior, a titanium
jacket 15.
[0041] Carbon graphite core 10 makes up the primary mass of
composite skull pin 5 and is effectively radiotranslucent. In one
preferred form of the invention, carbon graphite core 10 comprises
a cylindrical body 20 having a cone 25 on its distal end and a
cylinder 30 on its proximal end. Cone 25 terminates in a sharp tip
32 on its distal end. An annular shoulder 35 is formed at the
intersection of cylindrical body 20 and cone 25, and an annular
shoulder 40 is formed at the intersection of cylindrical body 20
and cylinder 30. Annular shoulder 35 preferably provides a stop or
support for the base 45 of titanium jacket 15, and annular shoulder
40 preferably provides a stop or support for mounting composite
skull pin 5 in a head frame, as will be apparent to those skilled
in the art in view of the present disclosure.
[0042] Titanium jacket 15 preferably covers only the distal tip of
carbon graphite core 10. In one preferred form of the invention,
titanium jacket 15 comprises a hollow cone 50 for covering cone 25
of carbon graphite core 10. Hollow cone 50 terminates in a sharp
tip 52 on its distal end. Hollow cone 50 is sized and shaped so
that it can overlie, and closely conform to, the exterior of cone
25. Preferably, base 45 of titanium jacket 15 engages annular
shoulder 35 of carbon composite core 10 when titanium jacket 15 is
mounted on cone 25 of carbon graphite core 10, so that the primary
load of engaging the skull of the patient is born by annular
shoulder 35. Alternatively, hollow core 50 of titanium jacket 15
and core 20 of carbon graphite core 10 may be formed so that the
primary load of engaging the skull of the patient is distributed
across substantially the entire surface area of cone 20 of carbon
graphite core 10.
[0043] Titanium jacket 15 provides the sharp distal tip of
composite skull pin 5 with the strength and integrity needed to
penetrate the scalp and grip the skull of a patient. However,
titanium jacket 15 is preferably very thin, e.g., only about 0.010
inches thick or less, or some other minimal thickness, so that the
titanium jacket constitutes very little mass and hence presents a
minimal X-ray signature. See, for example, FIG. 13, which shows the
X-ray image made using a composite skull pin formed in accordance
with the present invention, wherein the core of the composite skull
pin comprises carbon graphite and the distal tip jacket comprises
titanium. Note how the X-ray image of FIG. 13 is essentially devoid
of skull pin artifacts, due to the use of the composite skull pins
of the present invention.
[0044] Titanium jacket 15 may be secured to carbon graphite core 10
using glue or epoxy, or the various parts may be machined or
otherwise fabricated so that no glue or epoxy is needed.
[0045] Thus, the novel skull pin of the present invention
effectively comprises a composite structure, utilizing two
different components, formed out of two different materials, so as
to provide a superior skull pin. More particularly, the present
invention provides a novel skull pin comprising (i) a core formed
out of radiotranslucent carbon graphite, and (ii) a thin distal
jacket formed out of strong, hard titanium. This permits the skull
pin to have a low X-ray signature, since the major portion of the
skull pin (i.e., the core) is formed out of radiotranslucent carbon
graphite. At the same time, this construction permits the skull pin
to have the strong, hard point needed to penetrate the scalp and
grip the skull, since the distal tip of the core is covered by a
thin jacket of titanium. The titanium jacket is deliberately made
very thin (e.g., about 0.010 inches thick or some other minimal
thickness) in order to constitute very little mass and hence
present only a minimal X-ray signature.
[0046] See also FIGS. 14-18, which shows an alternative skull pin 5
also utilizing the novel composite construction of the present
invention. In the composite skull pin 5 shown in FIGS. 14-18, cone
25 of carbon graphite core 10 is not mounted directly on
cylindrical body 20 of carbon graphite core 10; rather, it is
mounted to the distal end of a cylinder 55 which is itself mounted
to cylindrical body 20. Furthermore, titanium jacket 15 is not does
not engage annular shoulder 35 of carbon graphite core 10; rather,
the proximal end of titanium jacket 15 comprises a plurality of
fingers 60 which interlock with a plurality of counterpart fingers
65 formed on cylinder 55 so as to support titanium jacket 15 about
cone 25. As a result of this construction, the primary load of
engaging the skull of the patient is born by the interface of
fingers 60, 65, i.e. it is not born by the distal tip of carbon
graphite core 10.
[0047] If desired, the radiotranslucent core of the present
invention can be fabricated out of a suitable radiotranslucent
material other than carbon graphite, and/or the strong, hard distal
tip jacket of the present invention can be fabricated out of a
material other than titanium, e.g., a synthetic plastic material
marketed by Integra LifeSciences Corporation of Plainsboro, N.J.
under the trade name Sapphire.TM..
Modifications of the Preferred Embodiments
[0048] It should be understood that many additional changes in the
details, operation, steps and arrangements of elements, which have
been herein described and illustrated in order to explain the
nature of the present invention, may be made by those skilled in
the art while still remaining within the principles and scope of
the invention.
* * * * *