(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2005/0245928 A1
`(43) Pub. Date:
`Nov. 3, 2005
`Colleran et al.
`
`US 20050245928A1
`
`(54) SYSTEM AND METHOD FOR
`DISPLACEMENT OF BONY STRUCTURES
`
`(75) Inventors: Dennis Colleran, Frisco, TX (US);
`Jennifer Diederich, Arlington, TX (US)
`
`Publication Classi?cation
`
`(51) Int. Cl? ................................................... ..A61B 17/56
`(52) Us. 01. .............................................................. .. 606/61
`
`Correspondence Address:
`DALLAS OFFICE OF FULBRIGHT
`JAWORSKI L.L.P.
`2200 ROSS AVENUE
`SUITE 2800
`DALLAS, TX 75201-2784 (US)
`
`(73) Assignee: Innovative Spinal Technologies, Plano,
`TX
`
`(21) Appl. No.:
`
`10/837,724
`
`(22) Filed:
`
`May 3, 2004
`
`(57)
`
`ABSTRACT
`
`Systems and methods for displacing bony structures relative
`to each other using a single device is disclosed. Displace
`ment includes distraction and compression. Bony structures
`are engaged With displacement arms. The user selects one of
`a plurality of manners in Which to manipulate a user inter
`face, Where a ?rst manner results in compression and a
`second manner results in distraction. The user interface is
`manipulated in the selected manner until a desired amount of
`displacement has been reached. This displacement is per
`formed in a manner that is minimally invasive to the patient.
`
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`Patent Application Publication Nov. 3, 2005 Sheet 1 0f 8
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`US 2005/0245928 A1
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`Patent Application Publication Nov. 3, 2005 Sheet 2 0f 8
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`US 2005/0245928 A1
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`Patent Application Publication Nov. 3, 2005 Sheet 3 0f 8
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`US 2005/0245928 A1
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`Patent Application Publication Nov. 3, 2005 Sheet 4 0f 8
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`Patent Application Publication Nov. 3, 2005 Sheet 5 0f 8
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`US 2005/0245928 A1
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`FIG. 8
`COUPLING A RECEIVING MEMBER TO EACH
`OF SAID AT LEAST TWO ANCHORS
`I
`INSERTING AT LEAST TWO ANCHORS INTO BONY STRUCTURES
`I
`EXTENDING A BRACE BETWEEN SAID RECEIVING MEMBERS
`
`801
`
`802
`
`803
`
`800
`
`INSERTING GUIDE TUBES OF A DISPLACEMENT DEVICE
`OVER ANCHOR EXTENSIONS TO GRIP ROD CAGES
`I
`TRANSMITTING FORCE TO ANCHOR EXTENSIONS
`TO DISPLACE BONY STRUCTURES
`
`805 f
`
`DETERMINE WHETHER ENOUGH
`DISPLACEMENT HAS OCCURRED
`I
`INTRODUCING SET SCREWS TO LOCK BRACE TO SAID AT LEAST
`TWO ANCHORS TO MAINTAIN THE DESIRED DISPLACEMENT
`I
`REMOVING SAID DISPLACEMENT
`DEVICE AND ANCHOR EXTENSIONS
`
`806 f
`
`807
`
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`
`6
`
`

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`Patent Application Publication Nov. 3, 2005 Sheet 6 0f 8
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`US 2005/0245928 A1
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`Patent Application Publication Nov. 3, 2005 Sheet 7 0f 8
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`US 2005/0245928 A1
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`Patent Application Publication Nov. 3, 2005 Sheet 8 of 8
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`US 2005/0245928 A1
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`US 2005/0245928 A1
`
`Nov. 3, 2005
`
`SYSTEM AND METHOD FOR DISPLACEMENT OF
`BONY STRUCTURES
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`[0001] This application relates to co-pending and com
`monly assigned US. patent application Ser. No. 10/690,211,
`?led Oct. 21, 2003, entitled “SYSTEM AND METHOD
`FOR STABILIZING OF INTERNAL STRUCTURES”, the
`disclosure of Which is hereby incorporated herein by refer
`ence.
`
`TECHNICAL FIELD
`
`[0002] The present invention relates generally to the medi
`cal ?eld, and more particularly to a system and method for
`displacing bony structures relative to each other.
`
`BACKGROUND OF THE INVENTION
`
`[0003] When a patient suffers from orthopedic injuries,
`deformities or degenerative diseases, it is sometimes neces
`sary to insert implants into the patient’s body to stabiliZe an
`internal structure, promote healing, or relieve pain. In the
`area of spinal surgery, for eXample, a common procedure
`involves the use of screWs or hooks joined by a connecting
`brace in order to secure bones. Once the brace is placed in
`the patient’s body, the brace must be ?rmly secured to the
`screWs or hooks in order to provide a stable construct Which
`effectively immobiliZes a corresponding portion of the
`spine. Then, a set screW or locking element presses against
`the brace to secure the brace to the hooks or screWs.
`
`[0004] When surgery is performed, the surgeon often
`needs to distract bone by pulling it aWay from the Work site
`or compress bone to pull it together if broken, as an eXample.
`In the area of spinal surgery, a surgeon may approach the
`spinal column of a patient from a posterior position, and
`force is applied in order to move implants along a rod in
`order to distract or compress bone or implants into the most
`favorable position. Force also may be applied to distract or
`compress prior to insertion of a rod.
`
`[0005] In the past, tWo separate devices have been used to
`perform compression and distraction. As an example, US.
`Pat. No. 6,716,218 issued to Holmes et al., teaches a device
`that performs distraction. If the surgeon desires to perform
`compression, another device Would be required. Addition
`ally, this type of compression or distraction device is not
`minimally invasive. Rather, a large incision is required to
`use this device. Thus, during a procedure, a surgeon has to
`sWitch devices depending on Whether compression or dis
`traction is desired. This need for sWitching devices may
`increase the amount of time required to perform the proce
`dure, and thus may result in a longer recovery time for the
`patient.
`[0006] Alternatively, certain devices are available that
`alloW for parts to be substituted, or changed out, in order to
`perform distraction or compression. As shoWn in US. Pat.
`No. 6,551,316. (“the ’316 patent”), for eXample, a device is
`provided having tWo sets of handles that can be selectively
`interconnected on an assembly. One set of handles Would be
`af?Xed to a jaW section When compression is needed. This
`?rst set of handles may be substituted With the second set of
`handles con?gured to be used for distraction as desired. If
`
`the surgeon desires to perform compression, one set of
`handles is attached to the assembly, and if distraction is
`desired, then the set of handles for compression must be
`removed and replaced With the set of handles for use in
`distraction. Accordingly, it takes time for the surgeon to
`replace the handles during the procedure. Further, the sur
`geon must remove the jaW section of the device from the
`patient’s body if he/she decides to employ a different tech
`nique, causing the length of the surgical procedure to
`increase. Additionally, the handles of the device described in
`the ’316 patent that the surgeon manipulates are relatively
`large, causing the device to be top-heavy due to the siZe of
`the handles. The surgeon’s hand Would likely cover approxi
`mately half to tWo-thirds of the handle portion in order to
`steady the device during the procedure. Thus, the device
`cannot be left unattended inside the patient. Also, the device
`of the ’316 patent is not minimally invasive, but instead
`requires a large incision to insert the jaWs of the device.
`Even if the surgical procedure itself is minimally invasive,
`use of the non-minimally invasive ’316 patent device Would
`effectively block the surgeon’s ability to visualiZe the opera
`tive site and to conduct the operation in a minimally invasive
`fashion.
`
`BRIEF SUMMARY OF THE INVENTION
`
`[0007] In vieW of the above, there eXists a need in the
`industry for a system and method for displacing, such as by
`compression or distraction, bony structures using a single
`device. Further, a need exists for a system and method for
`performing at least one of compression and distraction in a
`Way that is minimally invasive (e.g., by making a smaller
`incision to the patient).
`
`[0008] The present invention is directed to a system and
`method Which alloW for the displacement of bony structures,
`such as vertebrae of the spine relative to each other. Dis
`placement may include at least one of compression and
`distraction, and embodiments of the present invention pro
`vide for a device that may perform compression and dis
`traction interchangeably Without the need for having sepa
`rate compression and distraction devices. That is,
`embodiments of the present invention provide for an inte
`grated device that alloWs for compression and distraction to
`be selectively performed With a single device. Further,
`embodiments are provided that alloW for distraction and/or
`compression to be performed in a manner that is minimally
`invasive for the patient. That is, a displacement device is
`provided that minimiZes the incision made on a patient in
`order to perform displacement (compression and/or distrac
`tion) of bony structures.
`
`[0009] In certain embodiments, a medical instrument is
`provided that can perform both compression and distraction
`of vertebral bodies through at least tWo percutaneous inci
`sions. This instrument alloWs for either distraction or com
`pression to be selectively performed Without the removal or
`addition of parts to the instrument. Further, no substitution
`of the instrument is needed to perform distraction or com
`pression.
`[0010] The foregoing has outlined rather broadly the fea
`tures and technical advantages of the present invention in
`order that the detailed description of the invention that
`folloWs may be better understood. Additional features and
`advantages of the invention Will be described hereinafter
`
`10
`
`

`
`US 2005/0245928 A1
`
`Nov. 3, 2005
`
`Which form the subject of the claims of the invention. It
`should be appreciated that the conception and speci?c
`embodiment disclosed may be readily utiliZed as a basis for
`modifying or designing other structures for carrying out the
`same purposes of the present invention. It should also be
`realiZed that such equivalent constructions do not depart
`from the invention as set forth in the appended claims. The
`novel features Which are believed to be characteristic of the
`invention, both as to its organiZation and method of opera
`tion, together With further objects and advantages Will be
`better understood from the folloWing description When con
`sidered in connection With the accompanying ?gures. It is to
`be expressly understood, hoWever, that each of the ?gures is
`provided for the purpose of illustration and description only
`and is not intended as a de?nition of the limits of the present
`invention.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0011] For a more complete understanding of the present
`invention, reference is noW made to the folloWing descrip
`tions taken in conjunction With the accompanying draWings,
`in Which:
`
`[0012] FIG. 1 shoWs an eXploded vieW of an eXample
`embodiment of a displacement device;
`
`[0013] FIG. 2 shoWs a front vieW of the eXample dis
`placement device of FIG. 1 When assembled;
`
`[0014] FIG. 3 shoWs an isometric vieW from the back of
`the assembled displacement device of FIG. 2;
`
`[0015] FIG. 4 shoWs a front vieW of the eXample
`assembled displacement device of FIG. 2 Where one of its
`guides is angled so as to not be parallel With the other of its
`guides;
`[0016] FIG. 5 shoWs a cut-aWay vieW illustrating a stage
`of installation of an eXample stabiliZation device With Which
`embodiments of the displacement device may be used in
`certain procedures;
`
`[0017] FIG. 6 shoWs an eXample of the assembled dis
`placement device of FIG. 2 When in use With the eXample
`stabiliZation device of FIG. 5;
`
`[0018] FIG. 7 shoWs a cut-aWay vieW illustrating a stage
`of stabiliZing/?Xing the relative position of bony structures
`With the eXample stabiliZation device;
`
`[0019] FIG. 8 shoWs the eXample stabiliZation device
`resulting from the stabiliZation stage of FIG. 7 in accor
`dance With one embodiment;
`
`[0020] FIG. 9 shoWs an operational ?oW diagram displac
`ing bony structures relative to each other in accordance With
`certain embodiments;
`[0021] FIG. 10A shoWs another eXample embodiment of
`a displacement device having a different user interface than
`the eXample device of FIGS. 1-4, Wherein the user interface
`is con?gured for compression;
`
`[0022] FIG. 10B shoWs the eXample displacement device
`of FIG. 10A Where the user interface is con?gured for
`distraction; and
`[0023] FIG. 11 shoWs an eXample displacement device
`con?gured for multi-level surgery.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`[0024] Certain embodiments of the present invention pro
`vide a system and method Which alloW for both the com
`pression and distraction of bony structures, such as a spine,
`during a surgical procedure. According to certain embodi
`ments, a displacement device comprises at least tWo guide
`members connected by cross members Wherein the guide
`members are displaced relative to each other responsive to
`manipulation of a user interface. The guide members pro
`vide for the transmission of distraction or compression force
`percutaneously to bony structures, thus alloWing compres
`sion or distraction of these bony structures. Although vari
`ous embodiments are described With reference to a displace
`ment device that compresses or distracts, certain
`embodiments provide for a displacement device that per
`forms at least one of compression and distraction Without the
`need for a large incision, thereby performing compression or
`distraction in a minimally invasive manner.
`
`[0025] According to certain embodiments, it is unneces
`sary to disassemble or change parts on the displacement
`device in order to compress or distract. Thus, no assembly
`or disassembly of the displacement device is needed during
`the procedure, and it is not necessary to remove the device
`from the patient’s body if the surgeon desires to sWitch
`betWeen compression and distraction. The displacement
`device is light enough, and small enough, to be left affixed
`to the extensions Without holding. Thus, the device is
`suf?ciently stable so as to not be removed if the surgeon
`ceases using it momentarily. Further, because of the siZe of
`the displacement device, the device Will not interfere With
`the surgeon’s activities during an operation. As certain
`embodiments provide for a displacement device that is
`minimally invasive, accordingly the region of the patient’s
`body in Which the surgeon is operating does not need to be
`fully eXposed in order to perform compression or distrac
`tion. This results in minimal trauma to the patient and
`perhaps a faster recovery time.
`[0026] Embodiments of this displacement device may be
`used in certain procedures in conjunction With an implant
`able stabiliZation device for maintaining the relative dis
`placement of the bony structures acquired using the dis
`placement device. As an eXample, a stabiliZation device may
`include a brace connected betWeen anchors (e.g., pedicle
`screWs) that anchor to the displaced bony structures. The
`displacement device is used in order to ensure correct
`positioning of the brace-screW assembly and the implant
`device overall preferably before an implant device is stabi
`liZed. In certain procedures, the displacement device may be
`used before the brace of the implanted stabiliZation device is
`locked doWn to stabiliZe displaced bony structures.
`
`[0027] Embodiments of this displacement device may also
`be used in certain procedures in conjunction With an
`implantable dynamic stabiliZation device. Some dynamic
`stabiliZation devices have a need to distract elements of the
`spine to the insert the dynamic stabiliZation implant and then
`compress those elements to complete the assembly process.
`This device alloWs for the minimally invasive distraction of
`that dynamic stabiliZation device and aid in its insertion.
`
`[0028] FIG. 1 shoWs an eXploded vieW of one eXample
`embodiment of a displacement device. Displacement device
`10 is a device used to perform displacement of bony
`
`11
`
`

`
`US 2005/0245928 A1
`
`Nov. 3, 2005
`
`structures, such as vertebrae of the spine, relative to each
`other. The device 10 has tWo general elements: a user
`interface and a displacement mechanism. The displacement
`mechanism includes cross-action members and at least tWo
`guide tubes. Each of these elements are shoWn in FIG. 1 and
`Will be discussed in turn.
`
`[0029] The user interface, as shoWn in the example
`embodiment of FIG. 1, includes knob 112 and threaded rod
`110. Threaded rod coupling 108 is a receiving part for
`receiving the distal end of threaded rod 110. Threaded block
`111 provides a movable element threadably engaged to
`threaded rod 110 and movable along the longitudinal aXis of
`the rod 110 relative to receiving part 108 in response to
`rotation of knob 112. Shoulder screW 113 fastens threaded
`rod coupling 108 to the displacement mechanism. Knob 112
`is affixed to threaded rod 110 Wherein knob 112 can be
`rotated in order to displace bony structures relative to each
`other, as described further beloW.
`
`[0030] As Will be discussed further beloW, alternative
`embodiments may include a handle-based user interface
`rather than a threaded rod-based user interface (as Will be
`discussed in conjunction With FIGS. 10a and 10b).
`
`[0031] Moving to the displacement mechanism of the
`displacement device 10, there is shoWn cross-action mem
`bers for translating received input from the user interface
`into relative displacement of guides 102, 104 Cross-action
`members 106 and 107 are coupled together via head shoul
`der screW 114b. ScreW 114a connects member 106 to slider
`element 105a Which is inserted in channel 118 of engaging
`element 101, and similarly, screW 114c connects member
`107 to slider element 105b Which is inserted into channel
`115 of guide tube 104. As knob 112 is turned, cross-action
`members 106 and 107 then move relative to one another to
`ensure that guide tubes 102 and 104 perform compression
`and/or distraction as desired.
`
`[0032] Also, beloW the user interface, there is shoWn pin
`109 that mates the hole in cross-action member 106 to guide
`104. Pin 109 and the holes on the underside of threaded
`block 111 function together as a macro adjustment for initial
`placement of the device.
`
`[0033] Moving to the guide tubes of device 10, tWo guide
`tubes 102 and 104 (also referred to as “displacement arms”)
`are shoWn in FIG. 1. Guide tube 102 is mated With engaging
`element 101 to form an adjustable guide tube. Guide tube
`102 and engaging element 101 are movable relative to each
`other thereby alloWing guide 102 to be angled relative to
`guide tube 104 so as not to be parallel With guide tube 104.
`Guide tube 104 may be referred to as “stationary” Where
`guide tube 102 moves relative to it during displacement. Of
`course, movement of either or both guides may be per
`formed to achieve the relative displacement desired.
`
`[0034] As shoWn in FIG. 1, displacement device 10
`includes thumb slide 103 positioned relative to guide tube
`102. As Will be discussed in more detail With respect to FIG.
`4, thumb slide 103 is positioned on guide tube 102 and teeth
`117A engage teeth 117B of guide tube 102. When a user
`moves thumb slide 103 doWnWard (by engaging surface
`116) to disengage teeth 117A and 117B, angulation of the
`guide tube 102 may be changed. When the desired level of
`angulation is achieved, thumb slide 103 is released upWard
`and the teeth engage locking guide tube 102 at the particular
`
`angle. Spring 121 is arranged betWeen Wall 122 and thumb
`slide 103 to apply force to cause teeth 117A of thumb slide
`103 to engage teeth 117B of guide 102. When sufficient
`force is applied to thumb slide 103, spring 121 compresses
`enabling teeth 117A to disengage teeth 117IB.
`
`[0035] Further, engaging element 101 and guide tube 104
`of device 10 receive slider elements 105a, 105b through
`channels 118 and 115 respectively. As the user interface is
`manipulated for compression or distraction, slider elements
`105a, 105b adjust up and doWn their respective channels to
`provide the desired amount of movement in the cross
`members 106 and 107. As shoWn, there is a gradual sloping
`119, 120 on the surface of guide tubes 102 and 104 respec
`tively to alloW for gentle insertion through an incision and/or
`movement of the guide tubes Within an incision, thus reduc
`ing harm to the patient during the procedure. Displacement
`device 10 also provides for sloping of the leading edges of
`guide tubes 102 and 104 to alloW a surgeon to insert guides
`tubes 102, 104 along extensions into a patient’s body in a
`minimally invasive manner.
`
`[0036] FIG. 2 is a front vieW of the embodiment of FIG.
`1 When assembled. As shoWn, the tWo general elements
`(user interface and displacement mechanism) of the dis
`placement device are displayed. In this eXample embodi
`ment, a left-hand thread is used for threaded rod 110 of the
`user interface. Accordingly, When knob 112 is turned to the
`right (clockWise), the knob Will loosen and the distance
`betWeen knob 112 and threaded block 111 Will increase.
`Responsive to this action, the displacement device Will
`compress or tighten the bony structures. Thus, guide tubes
`102 and 104 Will be moved closer together resulting in
`compression. On the other hand, if knob 112 is rotated to the
`left (counter-clockWise), the device Will distract or loosen
`the bony structures relative to each other. That is, guides 102
`and 104 Will be pushed apart. This implementation may be
`desirable in that one typically thinks of turning a screW to the
`right (clockWise) to tighten (or compress) and turning the
`screW to the left (counter-clockWise) to loosen (or distract).
`Of course, in other implementations, a right-hand threaded
`screW may be used for rod 110 in Which turning knob 112
`clockWise results in distraction and turning knob 112
`counter-clockWise results in compression.
`
`[0037] FIG. 3 shoWs an isometric vieW of the eXample
`embodiment of FIG. 2 from the back. In FIG. 3, thumb slide
`103 can be seen. Further, the sloped portions 119, 120 on the
`surface of guide tubes 102, 104, along With the channels 118,
`115 for receiving slider elements 105a and 105b, respec
`tively, can be seen.
`
`[0038] FIG. 4 illustrates a front vieW of the eXample
`embodiment of a displacement device 10 of FIG. 2, Wherein
`guide tube 102 has been angularly adjusted. Thumb slide
`103 is used to alter the angular positioning of guide tube 102.
`As shoWn in FIG. 4, thumb slide 103 is positioned on guide
`tube 102 relative to guide tube 104 so as to not be parallel
`With guide tube 104. Angular displacement of guide tube
`102 is achieved by moving thumb slide 103 to disengage the
`teeth 117. Teeth 117A of thumb slide 103 engage teeth 117B.
`When the thumb slide shifts doWnWard, for eXample, the
`teeth are disengaged and the angulation of guide tube 102
`may be changed. While the teeth are disengaged, guide tube
`102 can be adjusted until the desired angulation is achieved.
`Responsive, slider elements 105a and 105b slide doWnWard
`
`12
`
`

`
`US 2005/0245928 A1
`
`Nov. 3, 2005
`
`in channels 118, 115 (in the direction away from rod 110),
`thus permitting the loWer ends 106A, 107A of cross-mem
`bers 106 and 107 to compress toward each other. This
`compression is translated to guides 102 and 104, Which in
`turn translate the compression force to anchors (e.g., screWs
`602 and 603 of FIG. 6) to Which the guides engage. Once
`guide tube 102 has been adjusted to its desired position
`relative to engaging element 101 to Which slide 105a is
`slidably engaged, thumb slide 103 is released, and the teeth
`117A, 117B Will lock guide tube 102 into place. Similarly,
`When distraction is desired, slider elements 105a and 105b
`slide upWard in channels 118, 115 (in the direction toWard
`rod 110), thus permitting the loWer ends (106A, 107A) of
`cross members 106 and 107 to distract aWay from each
`other. This distraction is translated to guides 102 and 104,
`Which in turn translate distraction force to the anchors to
`Which the guides engage.
`[0039] This angular adjustment may be desired, for
`example, When the positioning of the anchors are not
`arranged perfectly parallel to each other. Further, adjustment
`may be desired When a connecting brace positioned betWeen
`the anchors is not entirely straight (e.g., is curved to match
`the curvature of the patient’s spine).
`
`[0040] FIG. 5 shoWs a cut-aWay vieW illustrating a stage
`of installation of an example stabiliZation device 50 With
`Which embodiments of the displacement device of FIGS.
`1-4 may be used in certain procedures. More speci?cally,
`FIG. 5 shoWs a spine stabiliZation brace assembly that may
`be introduced into the vertebrae of a patient’s spine during
`a surgical procedure by coupling a brace to a pedicle screW
`as a single assembly as described further in co-pending and
`commonly assigned US. patent application Ser. No. 10/690,
`211, ?led Oct. 21, 2003, entitled “SYSTEM AND
`METHOD FOR STABILIZING OF INTERNAL STRUC
`TURES.”FIG. 5 shoWs the installation of example stabili
`Zation device 50 With respect to vertebrae L4 and L5.
`Embodiments of a displacement device described herein
`may be used With other stabiliZation devices such as that of
`US. Pat. No. 6,530,929 issued to Justis et al., or in proce
`dures that do not involve implanted stabiliZation devices at
`all.
`
`[0041] Although an example surgical procedure Will be
`described in further detail With respect to FIGS. 8 and 9, a
`brief overvieW of an example procedure may be helpful to
`put the use of a displacement device into context. A small
`incision may be made through the skin and a device is used
`to pinpoint Where a pedicle screW, such as pedicle screW
`602, is to be placed. Dilators, such as dilators 503 and 504,
`are introduced until a diameter suitable for passing the
`pedicle screW and its extensions is achieved. After the
`appropriate diameter is achieved, brace (or “rod”) 601 is
`attached to pedicle screW (“anchor”) 602 to form a brace
`screW assembly. The assembly is placed at the distal end of
`cannula 501, inserting pedicle screW 602 into a pre-tapped
`hole in vertebrae L4. Then, pedicle screW (“anchor”) 603 is
`inserted through cannula 502 into a pre-tapped hole in
`vertebrae L5. Once these screWs are in place, dilators 503,
`504 are removed, and a tool is used to part the muscle bundle
`beloW the skin betWeen vertebrae L4 and L5. The muscles
`and other tissue are only separated to a point Where brace
`601 may pass. Thus, the procedure may be performed With
`minimal invasion because no incision is needed betWeen the
`small incisions by Which cannulas 501, 502 may pass.
`
`[0042] After separating the muscles, brace 601 is posi
`tioned by pivoting brace 601 into position as shoWn by the
`arroW pointing doWnWard in FIG. 5. Again, this procedure
`Will be discussed in further detail later With respect to FIGS.
`8 and 9. HoWever, FIG. 5 shoWs hoW brace 601 may be
`positioned betWeen pedicle screWs 602 and 603. Once brace
`601 has been positioned in the area betWeen pedicle screWs
`602, 603, the surgeon may assess What angular and lateral
`adjustments may be made in the vertebrae L4 and L5, and
`accordingly, the surgeon may use the displacement device as
`described With respect to FIGS. 1-4 in order to make these
`adjustments before locking brace 601 into place. While
`brace 601 is used for stabiliZation in this example device, in
`other devices other types of elements may be used such as
`a ?exible material or a Wire. A cage, autograft or any other
`type of interbody fusion device may be placed in betWeen
`the vertebrae bodies. The device could be used With a
`dynamic stabiliZation device.
`
`[0043] FIG. 6 illustrates the example displacement device
`10 in use With the example stabiliZation device 50 of FIG.
`5. The guide tubes 102 and 104 of displacement device 10
`are placed over anchor extensions 606 and 607. Anchor
`extensions 606 and 607 are removably attached to rod cages
`605 and 604 respectively. Guides 102 and 104 may be
`displaced relative to each other responsive to manipulation
`of the user interface (knob 112 in this example).
`
`[0044] As shoWn in FIG. 6, When knob 112 is turned,
`cross-action members 106 and 107 move Which displaces
`guide tubes 102 and 104 relative to one another. Depending
`on Whether compression or distraction of L4 and L5 is
`desired, guides 102 and 104 Will either be placed in closer
`relative position to each other (by compression) or be
`pushed apart (by distraction).
`[0045] In an embodiment of the present invention, guide
`tubes 102 and 104 may be used to perform adjustments to
`the relative displacement of L4 and L5 after brace 601 is
`inserted betWeen pedicle screWs 602, 603 but before it is
`locked doWn to such pedicle screWs using locking caps. The
`pedicle screWs can be moved relative to each other by
`displacement device 10, Wherein rod cages 605, 604 are
`rotated and have angular motion to the heads of the pedicle
`screWs 602, 603. In an alternative embodiment, the pedicle
`screWs may be locked into position prior to insertion of
`locking caps. In this scenario, displacement device 10 may
`force a particular angulation on the pedicle screWs 602, 603
`even When the pedicle screWs have been locked into posi
`tion. In either case, a displacement technique, such as
`compression or distraction, may be performed. For example,
`While doing a fusion, the surgeon may ?rst perform distrac
`tion in order to insert an interbody device. Later the surgeon
`may compress the vertebrae to embed the interbody device
`and secure the stabiliZation device (With set screWs) before
`stitching the incisions made for each of the cannulas.
`
`[0046] When in use in the example procedure of FIG. 6,
`the majority of the displacement device 10 Would not be
`positioned inside the patient’s body. Rather, the skin line
`typically Would be just beloW the sloped portion 119, 120 of
`guide tubes 102, 104 respectively as shoWn in FIG. 6.
`Because most of the displacement device is located outside
`the patient’s body, smaller incisions may be used because
`the incisions Would only need to be as Wide as guide tubes
`102 and 104. Thus, no incision Would be needed for inser
`
`13
`
`

`
`US 2005/0245928 A1
`
`Nov. 3, 2005
`
`tion of cross-action members 106, 107 or threaded rod 110,
`for example, because no additional incisions are needed over
`those required for inserting the anchors. This is useful both
`for the patient and for the surgeon. The patient bene?ts
`because smaller incisions are made due to the smaller siZe of
`the inserted position of the displacement device, resulting in
`a potentially faster recovery time. The surgeon also bene?ts
`because he/she may perform distraction and subsequently
`perform compression Without having to remove the device
`from its placement in the patient or Without having to sWitch
`devices to perform each type of displacement. Further, the
`portion of the device that the surgeon operates is positioned
`far enough above the incision line that it is easy for the
`surgeon to turn knob 112 making it user-friendly to perform
`the desired displacement technique.
`
`[0047] After the desired displacement of L4 and L5 rela
`tive to each other is made, FIG. 7 shoWs a cut-aWay vieW
`illustrating a stage of stabiliZing/?xing the displaced posi
`tion of L4 and L5 bony structures With the example
`implanted stabiliZation device 50. Set screWs 701, or other
`locking devices, are introduced doWn cannulas 501 and 502
`to lock each end of brace 601 to its respective pedicle screW
`602, 603, While displacement device 10 (not shoWn in FIG.
`7) maintains the desired displacement of L4 and L5. Once
`the set screWs are locked doWn, the displacement device 10
`can be removed. The resulting implanted stabiliZation
`device 50 is shoWn in FIG. 9.
`
`[0048] Turning to FIG. 8, a How diagram for operation of
`a displacement device during a spinal procedure according
`to one embodiment of the invention is shoWn. The How
`diagram of FIG. 8 Will be discussed With reference to the
`device 50 described above. The resulting implanted stabili
`Zation device 50 is shoWn in FIG. 9. Assemblies 500 and
`700 (FIG. 9) are coupled to pedicle screWs 602 and 603,
`respectively in process 801. The pedicle screWs are
`assembled With the extensions and rod cages prior to