SELF-LOCKING HOLDING DEVICE WITH SINGLE-POINT FIXATION

SUPPORT AUTOBLOQUANT SE FIXANT EN UN POINT

English Abstract

The insert (4) of the holding device possesses fins (4b) that are arranged
according to the shape of a hole so that, after being introduced into the
hole, they are form-fitting, and make the hooks (4c) engage at the edge of the
hole. The locking piece (3), which fits non-positively to the inside of the
fins (4b), fixes the fins (4b) in position. The locking piece (3) in turn is
prevented from slipping out unintentionally by the fixing piece (1). Depending
on the embodiment, a pretensioning wheel (5) can increase the hold and allow
adjustment to different wall thicknesses (7), and a guide sleeve (2) can
enable intruments (6) to be guided precisely.

French Abstract

La partie d'insertion (4) du support selon l'invention présente des lamelles (4b) qui sont disposées, en fonction de la forme d'un trou, de façon telle qu'après introduction dans le trou, elles soient en liaison de forme et que les crochets (4c) viennent s'accrocher sur le bord du trou. La partie de blocage (3), qui est en liaison de force avec le côté intérieur des lamelles (4b), fixe les lamelles (4b) en position. Une sortie intempestive de la partie de blocage (3) est empêchée par la partie de fixation (1). Selon le mode de réalisation, une roue de prétention (5) peut augmenter le maintien et permettre l'adaptation à différentes épaisseurs de parois (7) et une douille de guidage (2) peut permettre un guidage précis d'instruments (6).

Claims

CLAIMS:
1. Self-locking holding device with single-point fixation,
characterized in that it has fins having hooks arranged
corresponding to the shape of a hole on the insert such that,
after being inserted into the hole, the fins 4b rest
form-lockingly against the hole and the small hooks 4c and let the
small hooks 4c project beyond the outer edge of the hole on the
side of the hole facing away from the holding device, the
subsequent inserting of the locking piece 3, which fits
force-lockingly on the interior side of the fins, fixing the fins in
their position, the clamping effect between the small hook 4c,
the fine 4b and the insert bottom 4e ensuring the hold, the
inserting of a fixing piece 1 preventing the unplanned sliding-out
of the locking piece 3.
2. Holding device according to Claim 1, characterized in
that the fixing piece has an adapter for holding or guiding.
3. Holding device according to Claim 1, characterized in
that the insert has fins 4b arranged in a ring shape and a round
locking sleeve 3 so that it can be inserted into a round hole.
4. Holding device according to one of Claims 1 to 3,
characterized in that it has a pretensioning wheel 5, the holding
device thus being adaptable to different wall thicknesses, and
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the hold being increased by the clamping in of the wall between
the small hooks and the pretensioning wheel.
5. Holding device according to one of Claims 1 to 4,
characterized in that a guide piece 2 is mounted between the
fixing piece 1 and the locking piece 3.
6. Holding device according to Claim 5,
characterized in that the guide piece 2 can be swivelled.
7. Holding device according to Claim 1 to 6, characterized
in that the guide piece 2, the insert 4 and the locking piece 3
each have a mutually aligned hole which permits the
guiding-through of instruments, tubes, hoses, etc.
8. Arrangement for carrying out the process according to
Claim 3 and 8, arrangement for removing the locking sleeve 3,
characterized in that expansion fins 14b are arranged on the
jacket of the remover 14 such that, after the insertion into a
recess in the locking piece 3, they rest form-lockingly on the
interior side of the locking piece 3, a pin 15 then fixing the
expansion fins 14b and permitting the pulling of the locking
piece out of the insert.
9. Arrangement for carrying out the process according to
one of Claims 1 to 7 for use with an instrument for determining
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the correct location of the bore hole, characterized in that the
target pin 9 and the fixing piece 1 with respect to their
mobility and construction, correspond to the corresponding parts
of the subsequently used holding device, the flexible pedicles
8a, in addition, allowing the pressing of the central marker onto
the desired spot.

Description

CA 02240456 1998-06-22
WO 9~/17191 PCT/CH97/OO~a6
SELF-LOCKING HOLDING DEVICE WI~H SI~GLE-POI~ ~IXATION
The invention relate~ to a holding device according to ~he
preamble of Claim 1. This holding device can be u~ed in many
different fields.
One po~eible field of application is the field of medicine;
for example, for maklng a biopsy in the field of neuro~urgery.
In neurosurgery, biop~ie~ are generally per~ormed a~ stereotaxic
su~gery. In the ca~e of stereotaxic ~urgery, the biop~y path is
de~ined by meane of the trepanation point and target determined
~y the ~urgeon.
For conventional ~tereotaxy, ~tereo~axy ring~ and target
bow~ are u~ed (~or example, the Kelly Sy~tem, Riechert ~
Mundinger, CRW, BRW; ~ee al~o: "Neuro~urgery", R.H. Wilkin~ and
S . S . Rengachary, 2nd Edition 1996, Volume III, Pages 4067, and
on, where a good overview of the present ~3tate of the art i~
found. ) The~e require a multi-point fixation in the tabula
externa of the skull cap ( exterior layer o~ the cranial bone).
Thi~3 thus fixed ~tereotaxy ring must be worn by the patient for
~e~reral hours which repre6ents a conE3iderable ~3train eo the
patient . In addition, the stereot~xy system limits the surgeon ' 9
operat lve act ion radiu~ .

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~ he ln~ention sol~es tank~, for example, in the field of
neuro~urgery which arl~e a~ the result of the further de~elopment
of the nuclear ~p$n tomograph or magnetic resonance ima~ing
~y~tem (MR~) to the interventional magnetic re~onance imaging
~ystem (IMR). The IMR produce~ real-time high-quality tomograms
0~ the body and, a~3 a pion~ering innovation, permit~ rgery on a
patient wh~le ~enerating imagee. In contra~t, in the ca-qe of
conventional ~tereotaxy, individual image~ produced before the
eurgery are u~ed a~ design fundame~tal~ for planning ~he surgery.
This method i~ unable to take into account change~ between the
generat ing of the tomogran~ and the surgery.
The fixed auxiliary reference sy~tem created and reguired by
the conventional ~tereo'caxy method i8 no longer required in the
IMR becau~e, during the whole surgical procedure, the patient lB
situated in the IMR with the reference system defined by the
fla~h point ~y~tem (FPS) auxiliary device connected to the IMR.
The FPS i8 a two- or three-LED guide who~e po!3ition in the
three-dimeneional ~pace is detected by three cameraE~. The FPS
allow~ the planning of a ~urgical procedure by defining an axi~3
which is computed into the lmage generated by the IMR and i~
displayed on a monitor in an i~ochronou~ manner.
The virtual axi~ generated by the FPS is made congruent wit~
t}-e biop~y path. It i~ now an object to maintain the found

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biop~y axl~ by a ~ixation of the FPS in the three-dimensional
space. The manufacturer of the FPS conceived this for a fixation
on a gooseneck. However, the goo~eneck~ known ~o far permit no
rellable fixation.
The lnvention permit~ a perfect fixation in the three-
dimen~ional ~pace becauce, in the case of the ~elected exa~ple,
it i~ fixed to the patient'~ skull cap. Furthermore, the
invention requires only little space and reduce~ the
inconvenience and ~urgery-caused etre~ to the patient to a
minimum.
The object i~ achieved according to the invention by mean~
of the feature~ indicated in the characterizing part of Claim 1.
Figure~ 1 to 18 illu~trate an embodiment of the invention in
the field of medicine. A~3 an example, an MR-compa~ible
con~truction was selected for a biop~y in the field of
neuro~urgery.
Figure 1 is an exploded view of the holding device;
Figure 2 ie a view of the assembled holding device in~erted
into the ~kull ~ap 7 with an introduced biop~y needle 6;
Figure 3 i~ an exploded ~iew of the localizer;

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Figure 4 i8 a view of an a~;~embled localizer with an applied
FPS 10;
Figure 5 i~ a v~ ew of a ra~;
Figure 6 i~ an exploded view ~f the combined in~trument of
the dura detaching in~trument and the mea~uring device;
Figure 7 iB a view c1f an a~;sembled combined in~trument;
Figure ~ i~ an exploded view of the locking sleeve remo~er;
Figure 9 i~ a view of the a~embled locking ~leeve remover;
Figure~ 10 to la illustrate a possible ~ouxse o~ an
applicatlon o~ the in~ention.
Figure 10 i~ a view of an insext 4 and a preten~ioning wheel
5 which are screwed together before ~eing in~erted into the ~kull
cap 7;
Figure 11 iH a view of t~e in~3ert 4 and the pretensioning
wheel 5 ineerted into the ~kull cap 7;
Figure 12 i~ a view of the locking sleeve 3 in~erted by

CA 02240456 1998-06-22
mean~ of the ram ll;
Figure 13 i8 a view of the fixing wheel l and the guide
~leeve 2 whlch are in~erted into the in~er~ 4;
Figure 14 in a view of the holding device which i~ inserted
in an assembled and operationally ready manner into the ~kull cap
7, 1/4 ~ectional view with the ineerted biop~y needle 6;
Figure 15 i~ a view of the locking :3leeve remover in the
relaxed condition before the removal of the locking sleeve 3;
Figure 16 i~ a ~iew of the locking sleeve remover which i~
engaged ln the locking E~leeve 3 but not locked;
Fiqure 17 i~ a view of the lockin~ sleeve remover which i~
locked by pre~sure on the head lSa;
~ igure 18 i~ a view of the removal of the locking nleeve 3.
In the following, the production and u~e of the invention i~
lllu~trated by mean~ of an embodiment from the field of
neurosurge~y.
For thl~ field of application, it i~ u~eful to produce the
invention of ~ynthetlc material~ (PEEK, POM) in order to prevent

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in~erfering artefact formation~ in the IMR.
The invention i~ ~a~ed on the idea of inserting a ~elf-
locking holding device into the bore hole required for brain
surgery. In thi~ e~bodiment, the holding de~ice~ ~ses the ~hape
o~ a cylindrical bore hole for finding a hold without ha~ing to
u~e third fixation point~.
In order to precinely determine the ~pot where the bore hole
i~ to be made, the FPS 10 is placed on the target pin 9 of the
localizer (Figure 4). The localizer i~ a~embled a~ illu~trated
in Figure 3. In this ca~e, the ball-and-socket joint of the
target pin gb i8 guided by the upper la and lower 8c joint
eocket~ contained in the fixing wheel 1 and in the localizer
~tand 8. T~e ~wivelling radiu~3 of the target pin 9 is limited by
t~e conlcal interior surface of the fixing piece 1 in a manner
uqed later for the limiting of the guide sleeve in the fixing
wheel 1. The target pin 9 can be fixed in it~ position by the
clo~ing of the ~ixing wheel 1.
The locallzer i8 now held by means of the pedicles 8a
againnt the patient ' 8 head and i8 moved around until the target
pin 9 or the axi~ calculated ~y the FPS point to the site to be
operaeed. The flexible pedicle~ 8a now make lt po~sible by mean~
of a pre~ing onto the localizer, to pre~-~ the central ~arker ~b
onto the ~calp and thu~ mark the point were the drilling i8 to be

~ CA 02240456 1998-06-22
carried out. The drill and the outer radiu6 o~ the fin~ 4b are
~elected ~o have the same ~ize.
After the placing of the cylindrical ~ore hole (normally of
a diameter of lS mm) in the ~kull cap 7, by mean~ of a dura
detaching device 12, the menin~ iB detached from the intexior
~ide of the skull cap 7 (Figure 6). ~hen, by mean~ of the
mea8u~emen~ ~cale 12a pro~ided on the dura detaching device 12,
the thickness of the 8kull cap 7 ~an be meaeured (Figure 7) and
thus the opti~al ~ize of the in~ert 4 can be selected. When ~he
in~ert 4 is guided through the bore hole, the flexible ~ins 4b
are compressed by the projecting small hook~ 4c to a smaller
radiu~. After the ~all hook~ 4c of the insert 4 have reached
the interior ~ide of the ~kull, the flexi~le ~in~ 4b will ~prin~
baek into their ini~ial po~ition, whereby the small hook~; 4c are
pres~ed over the ed~e of the bore hole (Figure 10 and Figure 11)
and prevent a ~liding back of the holding device out of the bore
hole. After they were guided through the bore hole, the flexible
fins 4b, which are arranged in a ring-~haped manner on the in~ert
4, rent flu~h on the bore hole. Then, by mean~ of the ram 11,
the locklng ~leeve 3 i8 in~erted into the insert 4 (Fiyure 12).
By means o~ it~ fit with the inside radiu~3 of the flexiblc fin~
4a, the locking 81eeve 3 prevent~ another ~p~inging-back of the
fins. By ~ean~ of the clo8ing of the preten~ioning wheel S, the
~kull cap 7 is now clamped in between the ~all hoo~s 4b and the
pre~en~ioning wheel 5. The preten~ioning wheel S permits the

~ CA 02240456 1998-06-22
taklng into account of different wall thicknesues of the ~kull 7.
The locking sleeve 3, in turn, is fixed in it~ po8i~ion by the
screwing-on of the fixing wheel 1.
The locking ~leeve 3 and the ecrewed-on fixing wheel 1 form
the upper la and the lower 3a integrated joint socket~ for the
ball-and-so~ket joint of the guide sleeve 2b. By mean~ of thi~
joint 2b, the guide ~leeve 2 can be ~wivelled in a ~electable
radiuY. Cones are therefore rece~sed in the axis of the guide
eleeve ~ in the fixing wheel 1 and the locking sleeve 3. As ~oon
as the guide ~leeve 2 ha~ reached the de~ired position, by me~n~
of a rotatlng on the fixing wheel 1, the guide ~leeve 2 can be
fixed in it~ ponition ~igure 13, 14). ~ow, the biop~y needle 8
can be introduced lnto ~he guide ~leeve 2 and the specimen can be
taken ( Figure 14).
The fixing wheel 1 i~ unRcrewed ~or removing the holding
device. Then, by means of the locking sleeve remover ( F'igure ~,
9), the locking fileeve 3 i8 removed (Figures 15 to 18) . ~n the
~tarting position, the pin of the locking ~leeve remover 15 i~
preu~ed ~o the upper ~top of he locking pin l5b in the pln detent
14c. Thu~, the locking ~leeve remover can be introduced into the
locking sleeve 3, becau~e the expan~ion fin~ 14b can be
compre~ed ~Figure 15, 16~ By a pre~ing onto the head ~Sa of
the locklng ~leeve remover, the expansion f in~ 14b are fixed ln
thelr po~ition (Fig. 17, 19) ~o that ehe locking ~leeve 3 can be

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removed. Tl~e ten~ioning wheel S i9 now rotated counterclockwiee,
whereby the ~kull ~ap 7 i~ no longer clamped in. sy mean~ of a
~light rotatlng and tilting movement, the insert 4 can he removed
f rom the bore hole.

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Numbering of the Individual Component Parte of the Patent
1 fixing wheel
la upper joint ~o~ket
lb grip indentation~
2 guide ~leeve
2a adapter for FPS (Fla~h Point System
2b ball-and-~ocket joint of the guide sleeve
3 locking ~leeve
3a lower joint socket
3b ineide cone of the locking ~leeve
4 ineert
4a grip ~ndentation~
4b flne
4c ~mall hook~
4d ~in elot~
preten~ioning wheel
5a out~ide cone of the preten~ioning wheel
Sb grip indentations
6 biop~y needle
7 ~kull cap

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3 localizer eupport
~a pedlcle
Bb central marker
8c lower ~oint ~ocket
g target pin
9a adapter $or FPS
9b ball-and-~ocket joint for target pin
fla~h point system (FPS)
ram
12 dura detaching device
12a mea~urement ~cale
12b underminlng head
13 meaeuring ~leeve
jacket of the locking slee~e remover (VHE)
14a guide bore
14b Yr~nRion fin~
l~c pin detent
pin of the locking ~leeve remover (VHE)
15a head

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15b detent pin
6 pre~E~ure ~pring
12

Representative Drawing