Note: Descriptions are shown in the official language in which they were submitted.
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I)ESCRIPTIO:N
MATERIALS COLLEC1'ION SYSTEl~ AND USES THEREOF
FIELD OF THE INVENTION
The present invention relates to iields of use where cuttings are collected from the
action of a cutting tool. Instrumentation and methods are provided for industrial and medical
applications. In particular, the present i:nvention relates to surgical instrumentation and a
rnethod of use t:hat allows skeletal tissue collection. Furthermore collected skeletal tissue
rnay be processed and transplanted, preforably within the donor subject to provide an
aLutologous tran~plant.
I~ACKGROUND OF THE INVENTION
In the production of machine parts to meet standard requirements for the U.S. military,
t:he U.S. Food and Drug Administration, and the International Orl~ani7~tion for Standards;
cutl~ings resulting from machining processes are collected and returned to inventory control to
account for all rnaterial issued to the shop floor. To account for all issued materials, scrap
cut:ings, residual bulk material, and machined parts are~ weighed ~o ensure that no unidentified
mal:erials are uncontrolled on the shop floor. Scrap cuttings from high-grade medical or
military specification materials are expensive and, therefore, cost effective to recycle. In
another example of collection of cuttings, jewelers collect and recycle materials that fall in the
wolk area during the machining of precious materials such as gold and silver.
The surg:ical harvest of bone, with or without marrow components, is a further
example of the need for instrumentation for collection of cuttings. Harvested bone material is
used in treatment of bone defects and diseases. The gc)al of therapeutic transplantation of
bone and bone marrow products is the induction or augmentation of bone growth and repair at
a defect site or around an implant site.
Autogenous bone grafts are the gold standard agrainst which all graft materials are
measured. Acquisition of fresh autogenous bone transplant material provides all naturally
available mitogens and growth factors in physiologic concentrations, viable mesenchymal and
progenitor cell populations, and natural bone matrix. Autograft bone has greater osteogenic
c'apacity than either allograft (tissue from donors of the same species) or xenograft (tissue
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f'rom donors of different species). In comparison to fi~ozen alloge~nic and decalcified allogenic
bone, fresh autogenic cancellous bone grafts lead to healing in most instances. Autogenous
bone grafts avoid the potential immunologic and infectious complications associated with
allograft materials.
;
Attempts to reduce morbidity associated with cancellous ~-~one harvest have usedrninim~lly invasive surgical techniques including use of cylindrical osteotomes that allow for
the harvest of scveral bone plugs obtained through a single initial cortical entrance. This
technique is slow and obtainable bone volume is limited. Bone biopsy trephines offer an
advantage that no muscle or ligamentou, attachments are disturbed, but again, the technique
lirnits harvest volume and shape, and collection of the harvested -rnaterial is tedious.
Other techniques have used square- or rectangular-shaped bone windows that
contribute to major donor-site morbidity. Angular defects produced in the formation of
common bone windows weaken bone structure because fractures can be propagated from the
corners of such defects
Devices and systems for bone cutting, and bone marrow tissue aspiration and
plrocessing for transplantation have been previously described. Bonutti (US Patent 5,269,785,
IJS Patent 5,403,317) and Thimsen et al. (Us l:'atent 4,649,919, lJS Patent 4,844,064) relate
to orthoscopic tissue removal. Johnson l'US Patent 5,443,468) and Leuenberger (US Patent
4,111,208) relate to drill bits and drill motor attachments: Abtopckomy (SU 1644923 A1),
Zelenov (SU 10~56578), and Michaelson (US Patent 5,45],227, arld WO 9505123) relate to a
bone tissue cutti:ng device; and Chin (U'; Patent 5,385,570) relates to a surgical cutting
instrument with a recess for collecting C]lipS of material. Bone rnarrow transplant methods
and a~ dlLls were described by Werner (US Patent 5,407,425), Gillis (US Patent 5,199,942)
and Altshuler (US Patents 4,486,188 andL 4,481,946).
Grant (U,S Patent 3,466,693) relates to the acti~e wiping of drill pipe for oil field use,
and Dillard (US Patent 4,991,452) relates to a sampler for hazardous solid materials.
Existing cuttings collection instrumentation fails to take into account the need for
cu.stom design for specific applications, l.he need for facile quantitation of collected material,
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the need for efi;cient transport to a second site, or the need for aseptic conditions or
environments having lowered oxygen levels, for exam.ple. In particular, existing skeletal
harvesting instrumentation and transplanting methods have encountered significant problems
,due to material characteristics and bone material harvest techniques employed. Existing
'; :methods and associated deficiencies include: 'I) genetically foreign bone and bone matrix
often elicit an infl;lmm~tory response and immunogenic rejection, 2) freeze-dried bone
implants from human donors are slow to vascularize a~nd pose unacceptable risks of
postoperative complications including disease tr~n.~mi~,~ion, 3) second-site surgery in the
patient to obtain autografts often result in high morbiclity and complications, 4) cortical bone
1() :implants are dif'ficult to shape and conform to a defect. site, 5) present bone harvest
.instrumentation and equipment are limited to trephines and curettes and limit quantity and
quality while requiring second-site surgery, and 6) a deficiency exists in present synthetic
bone matrix materials, such as compositions of calciurn phosphate and calcium carbonate,
silica glass, copolymers of polylactic and polyglycolic acid, and sea coral.
I ;
Because these prior art techniqucs are not completely sati.sfactory, the present inventors
have searched f~r improvements and provide the invention described herein.
SI~MMARY OF THE INVENTION
The pre~ent invention provides an instrument and method s for the collection of
cuttings that result from the cutting action of cutting tools. The instrument comprises a tip
adapted for use with a cutting tool, and a collection chamber attachable to the tip for
collecting and holding cuttings. When a cutting tool is inserted T.hrough the instrument, the
instrument acts independently from the cutting tool by allowing ~utting tool rotation along its
,~5 longitudinal axi i and translation of the cutting tool in and out through the instrument. When
in use, cuttings accumulate in the collection chamber.
By "adapted for use with a cutting tool" is meant that the tip serves as a cutting tool
guide, and can i.'urther serve as a cutting tool bearing. The tip haLs a bore for fitting to a
3('1 cutting tool. Aspects of the invention that cause the accumulation of cuttings in the collection
chamber include channeling from the action of a cutting tool, pulling due to translation of the
cutting tool, ancl flinging due to centripctal forces caused by rotation of the eutting tool.
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4 lPEA/~ tAY~
An embodiment of the instrument further comprises a cap attach~ble to the collection
chamber, the cap adapted for use with a cutting tool. ]3y "adapted for use with a cutting tool"
is meant that the cap serves as a cutting tool guide, ~md further may serve as a cutting tool
bearing. A cap may have a bore for fitting to a cutting tool, it may have a funher ~ttachment
S for rnixing contents of the ~tt~chment with c~1ttings in the collection chamber.
In another embodiment of the present invention, the instrument may further comprise a
w~per for wiping a cutting tool. The wiper may have a flexible or rigid protrusion, and may be
fittable into a wiper bushing that is att~ch~hle to the collection chamber or to the cap. The
protrusion for wiping a cutting tool may be flexible so as to contour to the cutting tool
10 surface, such as a wire, a bristle, or a brush; or the protrusion may be rigid and formed to
r ) m~tchingly fit c,r contour to a flute or cross-sectional outline of a drill bit. The protrusion for
wiping a cutting tool may &rther consist of a finger that runs against the outside of the cutting
tool to clear ma~terial and may be 1 1 ~d near the junction of the tip and collection ch&..lber.
Aspects of the further embo~ P ..ls of the invention that contribute to accum~ tion of
I S cutting~ in the collectior~ charnber include the use of a wiper as herein described and use of
suction from a vacuum line, for e~l.ple These aspects add the actions of wiping and suc~ing
to the previously desc-ibed actions of çh~nnrling~ pulling, and flinging as means by which the
present invention provides for the coUection of c~ g~ reS~lting from the use of cutting tools.
The tip of the instrument may further comprise a tooth or a plurality of teeth for
20 e~ ;ng slip~page on a cutting surface. The tip may be a spheriical tip or a swivel tip.
In a prefe,~,d embodiment of the invention~ the instrument further co--.p.ises aconcentrically oriented cutting tool. By "cutting tool" is meant a tool having a flute such as a
drill bit, bur, ~rinder, rasp, reamer, milling cutter, and the like, such as a hole saw. By
"concentrically oriented" is meant that the tool fits into the body of the instrument so as to be
:'5 substarlti~lly centered within the instrument. The cutting tool ma~ be fitted with an adjustable
stop, preferably with a calibrated adjusklble stop.
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In a further preferred embodimcnt of the instrllment of t}le invention having a cutting
tool, the cutting tool is a drill bit. The drill bit may have a standard tip, or a tip with a first
side and a second side, the first side having a straight cutting edge, and the second side
having a row of grinding teeth.
S
The cutl:ing tool may be rotated manually, hovvever~ the Instrument may further
comprise means for rotating the cutting tool for opti~li7ing the cutting action for hardened
materials such as metal. A preferred m.eans is an external motor.
] O In another aspect of the invention, the instrumlent further comprises an attachment for
pushing cuttings out of the collection chamber through the tip for application to a site. The
attachment may be a plunger that is inserted through the cap. In another aspect, the
altachment may be a dual plunger that is inserted into the colleclion chamber after the cap has
been removed.
The collection chamber may further comprise a means for measuring volume. In an
embodiment, the collection chamber has a transparent or translucent wall and the means for
measuring volume includes a volumetric marking on the wall. Such an instrument may
fwther compris~ a plunger for packing collected CUttiIlgS so that packed volume may be
:2() measured.
Certain of the parts of the instrument may be advantageol1sly fabricated as one unit so
as to provide a disposable unit, for exarnple. Such units may include the tip, the collection
chamber, and a wiper bushing; the tip and the collection chamber; or the cap, a wiper, and a
:2-j wiper bushing.
A drill bit having a tip with a first side and a second side, the first side having a
,traight cutting edge, and the second sid~e having a row of grinding teeth is a further aspect of
the present invention. Cuttings obtained by a process of using the instrument fitted with a
3~) cutting tool having said drill bit is another aspect of the invention.
In a further embodiment of the instrument of the present ~nvention, the collection
chamber further comprises an opening for connection to a vacuum line to provide suction.
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In an embodiment of the invention, skeletal tissue is harvl sted using the instrument
provided. In a :further preferred embodiment, l:he harvesting is performed aseptically so as to
provide materia] for transplant. By "skeletal tissue" is meant bony or more or less
cartilaginous framework of an org~nism, bone, bone nnarrow, cartilage, ligaments, spongy
5 bone tissue, or tendon, including intrinsic physiological factors thereof, such as growlth
factors, blood, biochemical or cellular components or constituent,. By "aseptic conditions" is
meant those sterile or near sterile conditions as operative in a surgical setting. As one of skill
in the art would realize upon reading this disclosure, aseptic would include sterilization of
instruments, suri'aces, solutions, and the like; use of stcrile ~arments, masks. and the like; and
10 fiill:ering of ambient air, for example. Sterilization ma~ be achieved by heat, ultraviolet light,
alcohol swabbing, or use of germicides, for example.
A materials transplant system is another embodïment of the present invention. The
system comprises an instrument of the present invention with or without a wiper, fitted with a
1.~ clltting tool, and means for moving cuttings to iLn alternate site oi use, such as a site of
irnplantation. In an embodiment, the cuttings are bone cuttings and the system is a sterile
~issue transplant system. The materials transplant system may further comprise means for
p]-c)cessing tissue, such as an encapsulation nozzle, for e xample. ~3y "means for moving
cllttings to an alternate site of use" is meant any means of transporting cuttings from the site
2() of lharvest to a diifferent site.
A method or use of a materials transplant system as described herein for aseptically
transplanting skeletal tissue from a first site to a second. site is another embodiment of the
invention. The method includes the stepsi of removing skeletal tissue aseptically from the first
25 site using the materials xransplant system herein described, and im~lanting the skeletal tissue
aseptically at the second site. The skeletal tissue may be processed before implanting at the
second site, and the processing may include washing, grinding, tissue separation, acid
addition, base addition, encapsulant additiion, or therapeutic agents including but not limited to
pharmaceuticals and growlth factor addition. In particular, the first site and the second site are
30 ~;viithin one subject so that the implant is i~m autologous transplant.
The instrument of the present invention is useful in any field of use where cuttings are
collected. Cuttings may be collected because the materials being (:ut are precious, i.e., rare~
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expensive, or have a special property, and where loss is undesirable. On the other hand,
cuttings may be toxic or hazardous, and collection of such cuttings is desirable to minimize
any hazard. Toxicity may be due to volatility, fl~mm~bility, radioactivity, or due to
biohazardous aspects, such as having a virus like the ]~IIV virus, for example.
';
In the n~l~chining of hazardous materials, the instrument ~nd methods of the present
-invention provide enhanced safety. Materials that are easily oxidized and present a fire
Ihazard such as titanium, magnesium, and sodium can be collected safely in the system since
oxygen pressure can be controlled within the system. The design of the instrument minimi7es
Il) ;my fire hazard by having a reduced access to oxygen in a substantially closed system.
~Vacuum can be used to remove powdered cuttings and further reduce collection chamber
oxygen tension. Furtherrnore, the collection system nsLay be flushed with an inert gas such as
argon, for minimi7ing combustion hazard.
:k'j In indusl:rial applications, gold, silver, platinum~, or uranium can be machined and the
cuttings can be collected for reuse, disposal, or to address safety or environmental concerns,
i-'or example. The instrument may also lbe used in a microgravity environment for the
collection of cu1ttings that would not otherwise be contained. By "microgravity" is meant any
e nvironment having a force of gravity less than that found on the surface of the earth, for
2() cxample, the space station environrnent.
In medical applications, the collection of cuttings of skeletal tissue is particularly
contemplated in orthopaedic or dental applications where bone and/or marrow is to be drilled
or aseptically harvested for subsequent rnedical use. 1 larvested skeletal tissue may be used for
2~i transplants, for Facilitating healing of bone defects, or for assisting implant acceptance. If
harvested tissue is a biohazard, the prescnt collection system enh~mces the safety of handling
such tissue by keeping it substantially contained, until disposal.
Particular materials contemplated by the inventc)r for CUttil1g with the instrument of the
'~CI present invention include skeletal tissue, metals, ceramics? and polymers. By "ceramic" is
rneant a material made of silica-based cc-ramic, silica ~lass, calci-lm carbonate, calcium
phosphate, hydroxyapatite, porcelain, or an aerospace ceramic, for example. By "aerospace
ceramic", is meant materials such as fibrous refractory composite insulation, thermoplastic
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syntactic foam, ceramic matrix composi.te, or l;he like. By "polyrner" is meant medical grade
~polymers such as polymethylmethacryla~te, pol5carbonate, polyst:yrene, polyvinylchloride,
silicone elastomer, or the like.
The instrument of the present invention can be used by following the steps of anexemplary orthopaedic procedure as follows: 1) place the instrument on bone, to locate the
cutting site, and provide a guide for the cutting tool, ïn this exarnple~ a drill bit, 2) place the
drill bit into the instrument, 3) drill in a manner consistent with clinical practice, 4) withdraw
the drill from the instrument, 5) hold th~e instrument at the drill ,ite so as to align the bore oi'
I () the tip and dril] hole to allow marrow tissues includin.g blood to well up into the tip and
collection cham.ber, 6) remove the instrument from the site, 7) compact the harvested material
within the instrument, ~) measure the volume of material collected, 9) extrude compacted
material through the tip or withdraw it from the bore of the collection chamber, and 10)
implant the mal:erial in a second site within the same patient.
In this ten step example, the independence of the instrument from the drill bit is
demonstrated in noting that the drill bit was used with the instrument in only three steps (2, 3
and 4), tissue was collected in three steps (3, 4 and 5,1 and tissue was manipulated within the
device in 6 steps (3, 4, 5, 6, 7, 8 and 9). In this exarnple, in addition to collecting tissue, the
:2() instrument was used to locate the site of drilling, brace the drill, guide the drill, control the
depth of drilling through use of an adjustable stop, protect surrolmding tissues from being
caught by the edge of the drill, and to collect, protect., store and transport tissue in a sterile
manner.
:2~ Advantages of the present invention include: 1') the instrument can be customized to
specific cutting procedures and requirements, 2) the instrument ~acilitates rapid and easy
volumetric quantitatiorl of collected material, 3) the instrumentation facilitates the efficient
utilization and placement of' collected cuttings in an alternate site, 4) the invention elimin:~tes
the practice of discarding and waste of valuab]e materials, 5) th~ invention can be used with
3() conventional drill motors and bits, 6) th.e invention efficiently combines three processes:
channeling, pul:iing, and slinging to collect cuttings, 7') the invention is adaptable to numerous
types of cutting tools, 8) the invention can be used to collect precious metal chips and dust, 9'
the invention can be used to automatically col]ect radïoactive material, 10) the invention can
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'~
be used to reduce the likelihood of a fire when cutting oxidizabl~ materials, 11) the invention
can be used to locate and brace a cutting tool. 12) a flute wiper of the invention can rotate
with the bit duri.ng rotation and translation, 13) the instrument can be held by hand, 14) the
invention is independent from the cutting tool in many of its use.~i, and 15) efficient collection
5 through the processes of channeling, pulling, and flin~;in~; can be further enhanced by adding
the processes of wiping and suctioning.
Further advantages of the present invention that are apparent in the application of
harvesting skeletal tissue include: 1) the invention allows harvest of cancellous and other
10 bone and/or malTow material from multiple donor sites, 2) the invention allows for optimal
processing of viable collected skeletal tissue for transplantation bv providing it in small pieces
with a high surface area and washed in vital marrow elements, 3) the invention minimi7es
biohazards assoc,iated with the disposal of hum~m bone cuttings, 4) the invention decreases
patient morbidit~y by decreasing haLrvest lime and allows the use of minim~lly invasive surgical
15 procedures, and 5) the invention decreases mechanical stress concentration and probability of'
iatrogenic fracture and morbidity.
Following long-standing patent laLw convention, the terms "a" and "an" mean "one or
nnore" when used in this application, including the clai]ms.
E~RIEF DESCRIPTION OF THE DR~WIN(,S
Further ~bjects and advantages oi' this invention will becorne apparent from
consideration of the drawings and ensuing description c~f the preferred embodiments.
Fig. l shows a cross-sectional plane view of an embodiment of the instrument of the
p~resent invention having a drill bit placed therein.
Fig. 2 shows an exploded plane view with some components in cross-section of an
embodiment of the invention.
Fig. 3a S]lOWS a cross-sectional p]ane view of a further embodiment of the invention
adjacent to bone and prior to drilling.
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Fig. 3b illustrates an embodiment of the invention durin~, a harvesting operation. The
drill body (150) is being rotated at speed (~') in a clockwise direction.
Fig. 4a shows an exploded plane view with some components in cross-section of an5 embodiment of the invention.
Fig. 4b shows a plane view of a tip of an inst:rument with means to grip bone surface
and pivot to provide a seal between the tip and bone.
Fig. 5a and 5b show a plane view of a fluted drill bit design that combines bothgrinding and cutting processes at the tip to optimize the morphology of cuttings and a large
flute with low flute angle to facilitate movement of cuttings up lhe drill and within the tip
( ] 00).
1.~ Fig. 6 s]nows a schematic of an embodiment o-l the invention that provides for aseptic
tissue transplantation f'rom a first site to a second site using an instrument of the present
invention. Harvested tissue may be processed to further enhanc~ its bone inductive potential.
Fig. 7 S]lOWS a dual plunger attachment within a collection chamber of an instrument
2() of the present i-nvention for extrusion of collected cuttings.
Fig. 8 S]lOWS a cross-sectional view of a dual plunger.
Fig. 9a shows a top view of a rotating drill flute wiper (~00) with rigid flute
:2~ protrusion (610) for drill bits with two conventional flutes.
Fig. 9b ;shows a top view of a rotating generic wiper (62i)) with flexible bristle-like
protrusions (63()) for use with a drill bit, tapered rea~ner~ bur. rasp, or saw.
3() Fig. 9c shows a top view of a rotating reamer flute wipet (640) with rigid or flexible
flute protrusions (650) for a multifluted reamer.
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11
I,IST OF REFERENCE NUMERALS
1 0, l 00 ti]l
103 spherical end tip
106 tip teeth
20, ll0 collection chamber
120 w iper bushing
130 drill wiper
30 140 c~p
150 drill bit
10 160 flute wiper
17() drill flute
18() swivel tip
18 . tip fixation prongs
186 swivel tip teeth
l 5 P9() cancellous bone
19 3 cortical b~)ne
195 bone cutt;ings
:20() cutting edge
2 I () grinding 1:eeth
2() 22() land
7 30 flute
240 drill shank
401 collection charnber
402 tissue suc~ion line
2S 4()3 tissue reservoir
4()4 vacuum pump
4()5 bone cuttings
4()6 roller pUlllp
4()7 tissue separator
3() 4()8 valve
4()'9 encapsul~lt
41 () encapsulation nozzle
4] l applicator
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12
412 encapsulated tissue
4 l 3 bone
4 l 4 iliac crest
5~0 tip plunger
5 510 collection chamber plunger
5'20 plunger head
5:30 plunger face
540 collection charnber extrusion face
1500 drill flule wiper
10 1510 drill flute protrusion
~$20 generic wiper
6 30 generic wiper protrusion
~40 reamer flute wiper
650 reamer flute protrusion
]I 'i;
DETAILED D15SCRIPTION OF THE' PREFERRED EMBOl)IMENTS
The pre~ent invention, in one exzLmple of its preferred embodiment, provides surgical
instrumentation that acts as a cutting tool brace for eff'icient cutting and collection of skeletal
tissue, including bone and cartilage tissue. The invention further provides for transfer of
2() harvested tissue to an implantation site. When the har-vest site arld implantation site are
within the same subject. the transplant is called an autologous transplant or an autograft. This
type of transplant is as close to ideal as can be achieved, since intrinsic growth factors and
rnatrix material are provided. and the possibility of immune rejection is avoided. When the
harvest site and implantation site are in different subjects, the transplant is called an
2~ a.llogeneic transplant or allograft, and th1 possibility ol immune rejection by the recipient
subject exists. An implantation site may be a structuri1l defect or a site of an implant in a
bone or cartilaginous site in a body, suc:h as an orthopaLedic impli.lnt or dental implant.
Freshly harvested bone or cartilage tissue can be described as being vital and having
30 imductive potent:ial. This means that freshly harvested tissue has gro~,vth factors and matrix
material that, when implanted in the donor patient, stimulate bone or cartilage to heal.
E,xemplary intrinsic growth factors and rnatrix material include, but are not limited to,
b-ansforming grc,wth factor beta, fibroblast growth fact~or, bone morphogenetic proteins,
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13
biocompatible scaffolding, and natural ]natrix material to facilitate bone to bridge large
fractures or fill defects. Growth factors, such as these and others, are contemplated as
optionally being added to harvested material to further enhance t~one healing at an implant
slte.
In a preferred embodiment of Fig. 1 and Fig. :3a, a surgi(:al instrument of the present
invention allows aseptic collection of bone and cartilage cuttings and comprises a tip (10,
1()0) that contacts bone and guides a cutting tool, a collection charnber (20, 110) that collects
.md holds bone cuttings, and a cap (30, 140) having a bore that acts as the upner cutting ~oo]
~150) guide and bearing. Together the tip (10, 100) and bearing cap (30, 140) center and
allow a cutting tool (1~0) to be rotated and translated by hand, ky using a handchuck, or by
use of an external motor. When fitted with a cutting tool such a., a drill bit (150), for
example as sho~,vn in Fig. 1, 3a, and 3b, the drill bit (15()) inserts longitudinally through the
body of the invention ~md serves to cut and grind bone cuttings ( 195) at its tip and translate
] ~i the bone cuttin~s (195) up the tip into the tissue collec:tion charnber (110).
The terms "bushing" and "bearing" are used interchangea~ly herein to illustrate that the
surface on which a cutting tool runs can be a simple bushing, or a roller bearing that turns
with the cutting tool and has no sliding contact between the surface of the tool and the
2 0 bearing.
The present invention efficiently combines three processes simultaneously to charmel,
pull, and fling cuttings resulting from the use of cutting tools into a collection chamber.
~hen a cutting tool is inserted through the instrument, the instrurnent acts independently from
25 thc cutting tool by allowing cutting tool rotation along its longitudinal axis and translation of
thc- cutting tool in and out of the entire instrument without being required to change the speed
or translational characteristics of the dril:l and its motor. When in use, cuttings are channeled
through the action of flutes, pulled through translation of the bit, Rung through centripetal
forces caused by rotation of the bit, and may be withdrawn using a fourth process through
30 evacuation of the collection chamber USillg suction.
A cutting tool may be a tool having a flute, such as for example, a drill bit, bur,
grinder, rasp, reamer, milling cutter, or the like. In a further embodiment, a wiper (130, 600,
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I~EAI~,', , . !~AY lg91
. 14
~i20, 640) is provided for wiping cuttings (195) from a tool (170) causing the cuttingS to be
deposited into the collection charnber (110) when the cutting tool is removed from the
instrument. Use of a wiper adds a fi~h process, that of wiping, to the herein described
processes of channelïng, pulling, flinging and sucking cuttings to more efficiently and
S completely clear all cuttingc from the cutting tool. When the cutting tool has a flute (230),
such as a drill bit (150), the wiper (130, 600, 620, 64tl) may be designed so as to fit into the
flutes (230) of l:he cutting tool. The wiper (130, 600, 620, 640) is concentrically oriented with
the cutting tool, and may have a protrus'ion (160, 610, 630, 650) in its bore that reaches into
the flutes (230) of a cutting tool to wipe the flutes of cuttings when the cutting tool is pulled
through the wiper. The wiper (130, 600, 620, 640) is free to rotate within the collection
chamber or an adjacent bearing housing, during cutting tool rotation or translation through the
instrument. In .an embodiment having a wiper desigr-e~ for a drill bit, a drill wiper (130, 600,
620, 640) turns with the drill bit (150) ~md allows drill bit (150) tr~nCl~tiorl The drill wiper
(130, 600, 620, 640) runs on an inner bore and is c,orltain~d within a wiper bushing (120). The
l S drill flute wiper protrudes into the flutes of the drill bit to clear the flutes of bone cutting~ and
blood; the wiper rotates within the collection chal~.b~r during drill bit rotation and translation
within the collection chan.ber.
Protrusions may be lobes (610, 650), hairs, wires, brushes (630), or threadlike
projec,tions (631)). A wiper (620) may be adapted to a tapered cutting tool. In one wiper
embodiment (6:20) the projec,tions (63()) are like the spokes on a wheel and flexible for
adaptation to tapered ,ea~.le-s with one or more flutes. This wiper (620) turns in the housing
so as to minimi7e rotational action of the bit against the spoke-like protrusions (630), while
allowing translation and wiping of tapered fluted bits or reamers A reamer wiper (640) with
irregular flute-slhaped protrusions (650) c,an be used ~ith the instrument.
Cutting tools may also be tools, such as a hole saw. Cylindlical saws having a bore and
cutting teeth on one end are used to corle material while cutting a round hole. In an alternate
embodiment adapted for a hole saw, cut material moves up the bore of the saw until it enters a
section of the saw bore that has a grealer internal diameter than at the tip of the saw bores
where it accumulates in a collection chamber. In this embodiment, the collection chamber
turns with the saw and inside a stationary housing. The instrument would have a tip and a
housin~ similar to the collection chamber of the preferred embodin-lent.
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through whieh the hole saw with eolleetion ehamber ~,vould rotale. A cap, fixed to the
~proximal end of the housing, would aet as a bearing and end for the colleetion eharnber
within the saw.
The surgieal instrument may further eomprise an attaehment that fits into the eollection
chamber that ac,ts like a plunger (500, 510) to push bone euttings (195) out ofthe eolleetion
chamber (20, l lO) through the tip (10, lO0) for application to a surgieal site. In operation,
~he plunger (50D, 510) is translated through the bore of the eolleetion ehamber (20, 110) to
-foree euttings out the tip (lO, 100). The plunger faee (530) is formed from ~liable material
ll.) arld tapered at a more gentle angle than that of the eolleetion ehamber extrusion faee (540) so
:hat, upon eontact, cuttings are first eompressed at the periphery of the plunger faee (530) to
e xtrusion face (540) contact area. As the plunger faee conforms due to its pliable material,
lhe eontact area grows in size and towards the tip (10, 100~) bore. This action extrudes all
materials into the tip (10, 100). The tip is cleared with the tip plunger (500) onee the
1:; eolleetion ehamber plunger (510) reaehes full travel.
The insbrument of the present invention may further eomprise an attaehment eontaining
bioeompatible materials, pharmaeeutieals, or biologies for mixin~ with bone euttings. The
attaehment would fasten to the bore of the eolleetion c,hamber (20, 110) and provide a means
ior mixing the contents of the attaehment with the bone euttings (195) within the eolleetion
chamber (20, 1 ] 0). The attachment ma'y be configure~.l with a screen for filtering cuttings by
size, or a mixer to stir the contents of the attachment with bone cuttings (195). The
attachrnent ean be used with a plunger to eombine the features of facile and accurate delivery
with the treatment of bone cuttings to enhanee effieacy in faeilitating bone healing.
The sur~ical instrument is preferably of a generally cylindrical shape, although the
instrument is not limited thereto. Alternative general shapes may be elongated and shaped for
case of use sueh as having a grip, preferably a grip that is ergon(:~metrically shaped. An
cmbodiment that has been fabricated and used in surgery is a cyllnder of about 1.25 inches in
,() cliameter and 4.0 inches in length. Cylinders of about 3/8 to 1/2 inch in diameter, and about
] inch in length are eontemplated for use with small bones; for use in industrial settings, a
cylinder having a diameter of up to about 1 foot and a length of up to about 1 foot is envisioned.
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16
Materjals suitable to fabricate the instrument include, but are not limited to, stainless
steel, delrin, polymethylmethacrylate, and polyethylene, for example. The tip, flute wiper,
and bushing rnay be fabricated of metal, and is preferably ma(~e from surgical stainless steel.
Alternative materials could be used, such as titanium~ cobalt, or titanium nitrate coated steel.
The cap, collection chamber, and wiper housing are preferably fabricated from injection-
molded high density polyethylene but can be formed from polymers including but not limited
to delrin, nylcln, polymethylmethacrylate, po]yester, polyvinylchloride, and polycarbonate.
Generally, metal parts should be resistant from cutting tool wear and selected from a family
of metals that is biocompatible so that a little wear debris will not adversely cont;~min~te
I() collected tissue. Generally, the polym.er parts can be formed of any material that can be
easily formed and sufficiently strong f'or the application.
The tip (10, 100. 103) contacts a cutting sur~ace without penetrating into it, and serves
as a cutting tool (100) guide or brace and bearing, while chanrleling harvested tissue into the
c collection chamber (20, 110). In either an embodiment having a wiper (130, 600, 620, 640)
or an embodiment lacking a wiper, the instrurnent's tip (10, 10()) forms the lower portion of'
the tissue collection charnber (20, 110,l and may have a lip to enhance stability and retention
in the collection chamber. The tip prcvides a pathway and means to move cuttings into the
collection charnber (20, 110). The tip (10, 1()0) has means to elimin~te slippage on bone and
trap bone cuttings (195) in the cutting tool flute (170) to channel the bone cuttings up the tip
(10, 100) and :into the collection chamber (20, 110).
A serrated edge or sharp tip teeth (15, 106) located directly on the cylindrical portion
of'the tip (10, 100) or on a swivel tip 1'180) held with elastic tip fixation prongs (183) can be
used to elimin,lte slippage and channel bone cuttings (19~). A ~;wivel tip (180) rotates about
the lower end of an optional sphericall~y ended tip (1()3) so as to provide good cortical bone
(193) contact.
The collection chamber body (20, 110~ may attach to a cap (30. 140) or to a wiper
bushing (120). When fabricated to attach to a cap (30), the open end of the collection
chamber (20, 110) may have a positive lip on the internal diameter to lock with the cap. The
collection chamber (20, 110) requires no moving parts and takes advantage of the movement
of cuttings up cutting tool flutes, pulling of tissue thrc)ugh the tip and .~linging of cuttings to
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deposit cuttings in the collection chamber. The collection chamber (20, 110) can be further
enhanced b~ having an opening for connection to suction (4()1) to facilitate the collection of
cuttings and to facilitate collection c~f blooci. The collection chamber (20, 110, 401) may
have a means of measuring collected tissue volume not limited to a volumetric marking, or
transparent or translucent outer walls which together with a volumetric marking, can be used
to measure ~mpacked volume. A plwnger (500, 510) may be used to compress said bone
cuttings for l:he measurement of pack;ed volume.
The cap (30, 140) mav attach to the s~ollection clhambcr (2C, 1 iO) or to a wiper
]0 bushing (120). The cap (30, 140) may have a groove on the outside diameternear one end to
lock with a li.p in the bore of the collection chamber (20, 110); other types of connections
may be threads, o-rings or a quick di;sconnect member. The cap (140) may house a flute
wiper (130) that is held in through the use of a press-fit cylindrical bearing.
An embodiment of the invention is shown in Fig. 3a in contact with cortical bone(193) prior to drilling. The invention is sho~n in operation in Fig. 3b with cortical bone
(193) and cancellous bone (190) being drilled and bc~ne cuttings (195) moving up the drill
flutes (170) and being deposited in the collection chamber (110).
2() In one aspect of the invention, the surgical instrument is designed for use with a drill
bit. A drill bit having a tip that both grinds ~md cuts bone (20(" 210) to optimize the size of
bone particles for specific transplantation purposes is an aspect of the invention (Fig. 5a and
~b). The bit tip has teeth (210) and a cutting edge (200) at the entry to its flutes to grind ancl
cut bone while creating a bore in bone. The teeth and cutter geometry can be chosen to
''~ adjust the particle size of bone cuttings. The drill may have a large flute volume and low
flute angle to facilitate bone cutting movement into the tissue c(}llection chamber.
Drill bits of most any design may be used, and the qualily of the bone cuttings (19~)
can be optimized through the use of a specialty bit in one embodiment. The cutting edge of a
specialty drill bit tip has a straight cutting edge (200) on one side, and has a row of grinding
teeth (210) on the other side. The grinding teeth (210) protrude from the tip of the drill
beyond the cutt:ing ed~;e (200~ and serve to grind and loosen material for the cutting edge
(200) to sever and scrape into the entry to the flute (230).
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Further aspects of a drill bit that are contemE)lated as p,lrt of the present invention
include the following. A land (220) can be optimized for different applications using
different flute volumes and angles to llanslate bone cuttings (1~5) or marrow tissue. A drill
shank (240) ~~ithout fluted section attaches to a drill motor and serves to stop translation of
'; the drill through the drill wiper (130) through interference between the flute wiper (160) and
Imfluted section of the drill shank (240). The drill shank (240~ can be fitted with a calibrated
adjustable stop to allow precise control of drill penetration deplh.
The surgical instrument may be a single use cievice, i.e. a disnosable unit that is
] 0 provided in a sterile package to a user. In particular~ models adapted to fit drill bit diameters
of 2-4 mrn, 4-6 mm, 6-8 mm, 8-10 mm, and 10-12 mm are contemplated.
Another embodiment of the invention includes the surgical instrument described herein
and further includes rneans for transferTing harvested tissue to ~a second site with optional
lS processing of lhe harvested tissue. In this embodiment, the collection chamber (401) is
connected to a suction line (402) to move bone cuttil1gs (405) and fluid collected from a
surgical site, such as -the iliac crest (414), so that it can be stored in a tissue reservoir (403).
Vacuum is su~plied to the system by a vacuum pump (404) connected to the tissue reservoir
(403). Collected material in the tissue reservoir (403) is movea using a roller pump (406) to
a tissue separal:or (407). The tissue separator (407) can contain screens, filters, centrifuge
units or other cell and tissue separatin~ devices as well as acid cmd basic solutions to modify
the collected tissue. The tissue transpL~nt system ma~y comprise a pump, filter, centrifuge~
mixing chamber, settling chamber, con,duit, and the like. The sYstem may have an applicator
for the implantation of collected skeletial tissue. Skeletal tissue may be harvested from a
variety of sites, such as rib, fibula, iliac bone, craniurn, sternum tibia, or the like.
For example, a centrifuge may be used to fractionate the harvested tissue and remove
red and/or whil:e blood cells; or harvested tissue may be chemically washed so as to increase
the bone inducl:ive potential of various proteins and cells while m~int~ining their viability.
Processing may include steps to enhance the bone forming potential of said bone cuttings not
limited to filtering, rinsing with water, grinding of saiid bone cuttings, washing with acid
solutions, and washing with basic solutiions.
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Processed tissue components c~m be combined or sent separately to the site of
implantation through a valve (408) to an encapsulation nozle 1410) where an encapsulant
such as algin, poly-L-lysine, collagen, polylactic acid, polyglycolic acid, methylcellulose~
glycerol, saline, calcium phosphate, or calcium carbonate from an encapsulant reservoir (409,
5 can be combined with the tissue. Encapsularlt with tissue (412~ or tissue alone can then be
applied at a bone (413) defect site with an applicator (411). A positive displacement pump
(406) provides the positive pressure to move the material through the processing stage and to
the implant site.
:10 Cancellous bone is cell rich and integrates rapidly with recipient bone and is resistant
lo infection. In comparison with solid bone grafts, particulate or paste-like bony materials
c~ffer considerable advantages. Further advantages of fresh autograft bone chips or particles
include; high ~;raft surface area facilitating vascularization and remodeling, healing would
occur as a "field phenomenon" occurring simultaneously throughout the entire defect,
] 5 irregularly shaped defects can be filled more c,ompletely with contact between host site and
graft tissues closer and more extensive, and only a small surgical access is necessary to f1ll a
large bone cavity defect. Furthermore, bone cells within cancellous bone graft material placecl
in contact with a well-vascularized recipient bed will survive, and storage of harvested
cancellous bone material in normal saline ensures cell survival in the 95% to 100% range
even after a working time of up to four hours (Marx R. ef ~1. J. Oral Surg. 37: 712-718,
1 g79).
An aspect of the invention is the use oi the herein described tissue transplant system
combined with the addition of growth factors ~md matrix material to enhance bone wound
.25 healing. Addition of such factors and material is expected to optimize the state of the
:harvested skeletal tissue. Such factors ~md material include, for e xample. transforming gro~,vth
:factor beta and alpha, bone morphogenetic protein, platelet derived growth factor, epithelial
g,rowth factor, fibroblast grov~th factor, vascular permeability factor, mitogens, mesenchymal
cells, progenitor cells, and natural bone matrix.
~I)
Procurement of tissue may be separated in time by implantation into the donor or into
a different recipient. One of skill in the art would realize, in light of this disclosure, how to
llse the instrumentation of the present invention when tissue is harvested from one patient and
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implanted into a different patient.
In the operation of the invention, drilling of skeletal tissue for reeonstruetive surger~?
or for plaeement of orthopaedic, dental, oral, or maxillofaeial implants sueh as plates, screws.
5 or rods is performed using aseptie teehnique. The drill euttings are eommonly disearded; wit;h
use of the present invention, the drill euttings are eolleeted and ean be plaeed around the
implant to further anehor the implant and faeilitate healing. The invention is used in
eonjunction wil:h eommon drill bits ancl drill motors.
] 0 The method involves aseptie coi.leetion and transfer of bone euttings andlor marrow
constituents for imrnediate transplantation. Tissue collected from use of the surgical
instrument provided by the present invention is cortical and cancellous bone combined with
marrow tissues and blood that form a paste-like graft material. This material has paste-like
handling propelties, high surface area, and a generally open strueture. These features of the
:methods of the present invention facilitate h~n~lling, vascularizatlon, modeling, and provide a
bone-inductive seaffolding for enhaneernent of healing of a surgieal site.
In praetiee of a preferred embodiment, a drill bit (150) is inserted through the eap
l~140), wiper bushing (120), drill wiper (130), eollection chamber (I 10) and tip (100).
]Rotation of the drill bit (150) cuts bone. Bone cuttings (195) ar~, confined within the drill
flute (170) by the tip (100). Continued rotation of the drill bit ( 150) causes translation of the
bone cuttings (] 95) up the inner bore of the tip (100). Bone cuttings (] 95) that have moved
up the tip (100) and into the collection ehamber (110) fall from the drill flutes (170) and
collect in the collectiol1 chamber (110). Bone cuttings rem~inin~ in the drill tip (10, 100) can
2"i be pulled into the collection charnber (20, 110) through drill bit translation and cuttings
rem~ining in the drill flutes (170) are removed from the drill flutes (170) by centripetal force?
suction, or the clrill wiper (130).
The drill wiper (130) is free to rotate in the wiper bushing (120) along its eommon
~0 clXiS with the drill bit (150). The flute wiper (160) of the drill wiper (130) extends into the
clrill flute (170) to wipe any residual bo:ne cuttings that have not collected in the collection
chamber (110). The drill wiper (130) hlrns with the drill bit when it is rotated along its long
aLxis or when the drill bit is tr~n.~l~ted through the tip ( 100), collection charnber (110) and drill
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- 21
wiper (130).
The tip (100) is connected to the tissue collection chamber body (110). The collection
chamber (110) connects to the wiper bushiIlg (120) which serve; as a bearing surface and
guide for the drill wiper (130). The drill wiper (130) rotates freely in the wiper bushing
(120) and is confined by the cap (140) which is connected to th, wiper bushing (120). The
tip (100), collection chamber (110) and wiper bushing (120) can be combined into one part
and fabricated as a disposable instrume:nt.
The surgical instrument is used ~vith conventional surgicdl drill bits. A drill bit of the
appropriate diameter, flute length and overall ].ength is inserted into the a~ opfiate model of
the surgical instrument from the cap end. The instrument is held in one hand and the tip
positioned on bone at the point of drilling. As bone is drilled, bone and /or marrow tissue
fragments are carried up the flutes of the drill bit, through the tip and passively fall from the
flutes into the collection chamber. The drill bit can extend beyond the tip of the instrument
up to about 3-5 inches, and the instrument may be moved in an arc motion so as to harvest
tissue from a cone-shaped area of the bone. ~Ihen the drill bit i, translated longitudinally
away from bone ~vithin the instrument in and out of the tip, rota~ing action further acts to
displace material from flutes into the collectioIl chamber, and in an embodiment having a
wiper? movement of the drill bit through the wiper serves to displace material into the
collection charnber.
The description of the embodiments and their operation i~ given not to limit the design
arld scope of the invention but to broaden the description of the invention to include any
~5 ~method or device that uses a surgical instrument of the present invention and achieves the
goal of harvesting and processing of borle or marrow tissue for the purpose of transplantation.
Even though the invention has been described ~,vith a certain degree of particularity~ it
is evident that rnany alternatives, modifications, and variations will be apparent to those
skilled in the art in light of the foregoing disclosure. Accordingly, it is intended that all such
alternatives, modifications, and variations which fall within the spirit and the scope of the
invention be embraced by the defined c]aims.
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The followin,~; example is included to demonstrate a preferred embodiment of theinvention. It should be appreciated by those of skill in the art that the techniques disclosed in
the example represent techniques discovered by the inventor to function well in the practice of
the invention, and thus can be considered to constitute preferred modes for its practice.
I~owever, those of skill in the art should, in light of the present disclosure, appreciate that
many changes can be made in the specific embodiments which are disclosed and still obtain a
like or similar result without departing from the spirit and scope of the invention.
EXAI~IPLE 1
]10 Collection of Skeletal Tissue
A surgical instrument according to the present invention was built and tested in a
cadaver and in living ~nim~l.s. The device was used with a conventional drill bit in fresh
cadaver femoral bones. Bone cuttings were collected following a few revolutions of the drill
bit. Cuttings nnoved up the flute within the conf1nes of the tip. Cuttings exited the flute once
they passed the tip and entered the collection chamber. The white color of cortical bone was
seen through the collection chamber window and cancellous chips were coated with a small
quantity of blood. Six 0.272 inch holes of approximately 2 cm depth were made. With each
new hole the collection chamber continued to fill. The large quantity of osseous tissue
collected in the chamber quickly obscured the view of the drill.
While drilling, the flutes were noted to retain some of the cuttings. To test the
performance of the flute wiper, the drill bit was withdrawn. When removed from the device~
the flutes were noted to be clear of cunings and the cuttings were seen to fall into the
cc)llection charnber. Ihe action of the rotating wiper was smooth and did not cause the bit to
2.~ bind during drilling or withdrawal. At the desired drill depth, the bit could be quickly pushed
in and pulled oLlt to collect additional osseous tissue from the margins of the drill hole, or to
pump blood into the collection chamber that ~as hemorrhaging mto the site. Use of a
vacuum in conjunction with the device could facilitate collection of more blood if clinically
advantageous. Once drilling was compLIeted, the drill bit was withdrawn for the final time.
:3()
In one embodiment of the invemtion, the cap and wiper bearing are fabricated as one
unit, and this Ullit may be removed together with the rotating flute wiper. The collection
c hamber and tip also may be fabricated as one piece. A plunger assembly will connect to the
collection chamber and facilitate clearing of the harve.sted osseous tissue from the device. This
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23
plunger assembly would allow harvested osseous tissue to be forced from the collection
chamber throu~,h the tip to facilitate application to a site of injury, fusion, or implantation.
With plunger assembly attached, the device allows placement of collected osseous tissue and
blood.
Following collection, the collection chamber was emptie~1 of osseous tissue. Theosseous tissue was noted to consist of coarse cuttings with varied dimensions of approximately
0 5 mm X 4 mm X 8 mm. Blood coated the cuttings~ however. no free liquid was present in
the collection chamber.
I()
Tissue was evaluated for volume and the values were compared to theoretical values
based on the dimensions of the drill hole; tissue was also evaluated for weight and those
values were compared to theoretical weight which was calculate~l using the density of the
bone segment nnultiplied by the volume of the drill hole. The ti ,sue collection data are
1~ provided for volume comparisons in Table 1, and for weight comparisons in Table 2.
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24
Table 1: Tissue Collection Comparison l~y Volume
Sample Number Harvested Tissue Theoretical Tissue Harvested Tissue
Volume (cc) Volume (cc) as a % of
Theoretical
103951 0.6'j 0.65 100
103952 0.6,~ 0.60 103
103953 0.6(~ 0.54 111
103g54 0.5'3 0.53 109
103955 0.5~) 0.58 97
103956 0.5(~ 0.60 98
103957 0.6() 0.61 98
928951 0.8() 0.71 112
928952 0.3il 0-30 103
928953 0.2~) 0.26 100
928953 0.2(~ 0.30 96
l:j 102951 2.4 2.6 93
Table 2: Tissue Collection Comparison By Weight
2()Sample Number Harvested TissueTheoretical Tissue Harvested Tissue
~Jeight (grams) Weight (grarns) as a % of
Theoretical
103951 0.5'~ 0.98 56
10:3952 0.54- 0.93 58
10.3953 0.53 0.88 60
10:3954 0.5CI 0.85 59
:2'j10:3955 0.4~' 0.85 58
10:3956 0.5CI 0.89 56
103957 0.54- 0.91 59
10'~951 3.1 3.1 100
:30 The surg~ical instrument was used in a living animal in both iliac crest and proximal
tibial metaphysis sites. Two holes were drilled in each location. The observations made
during the drilling of fresh cadaver bone and the sites in the live animal were consistent.
Osseous tissue collection was achieved with the bone cuttings having a light coating of blood.
~BIood in the collection chamber was not of sufficient quantity to form free liquid. The two
drill holes in the tibia produced 0.45 cc or 0.48 grams of bone. The two drill holes in the
iiliac crest produced 0.'31 cc or 1.09 grams of bone.
These data demonstrate that the surgical instrument of tht present invention is
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straightforward to use and allows collection of vital osseous tissue for placement at an injured
site. With the use of this device, a hole drilled in bone to fasten an implant or place a screw
,can be a source of highly inductive tiss-ue capable of enhancing ~he healing response of bone,
Fllling large bone defects, or facilitatin~ fusion of unstable or diseased joints.
.5
All of the compositions and methods disclosed and claimed herein can be made ande xecuted without undue experimentation in light of the present disclosure. While the
cc)mpositions ar-d methods of this invention have been described in terms of preferred
embodiments, il: will be apparent to tho,e of skill in the art that variations may be applied to
he composition, methods and in the steps or in the sequence of steps of the method described
herein without departing from the concept, spirit and scope of the invention. More
specifically it ~;vill be apparent that certain agents which are both chemically and
physiologically related may be substituted for the agents described herein while the same or
similar results vvould be achieved. All such si]nilar substitutes and modifications apparent to
1'~ lhose skilled in the art are deemed to be within the spirit, scope ~md concept of the invention
clS defined by the appended claims.
