Source: https://patents.google.com/patent/US7850695B2/en
Timestamp: 2019-04-23 08:47:23+00:00

Document:
This application is a Divisional of U.S. patent application Ser. No. 10/280,489, filed Oct. 25, 2002, now U.S. Pat. No. 7,056,321, entitled METHOD OF SECURING VERTEBRAE, which is a continuation-in-part of U.S. patent application Ser. No. 09/630,077, filed Aug. 1, 2000 (now U.S. Pat. No. 6,530,926), entitled METHOD OF SECURING VERTEBRAE.
FIGS. 1-5 illustrate one suitable cannula or expandable conduit 10 constructed for use in a method in accordance with the present invention. The cannula 10 is a tubular structure 12 centered on an axis 14. The tubular structure 12 defines a passage 16 through the cannula 10. Surgical instruments are inserted into the body during surgery through the passage 16.
As viewed in FIG. 10, the second support 140 supports a viewing device 200 including a camera head 201 and an endoscope 202 with a rod and lens assembly 203, herein referred to as a viewing element, extending down through the passage 16 of the cannula 10. The second support 140 includes a body 142 having an opening 144 through which the viewing device 200 extends and a clamp 146 for clamping the viewing device 200 to the body 142 in the opening 144. The clamp 146 includes a threaded set screw 148 for securing the viewing device 200 to the body 142. The set screw 148 has a manually rotatable knob 148 a and a stem threaded into the body 142. When rotated, the screw 148 moves axially relative to the body 142 to clamp or release the viewing device 200 depending on the direction-of rotation of the screw 148.
The cannula 10, support apparatus 110, and vertebral fixation assembly 620 described above may be used to perform an operation which secures two vertebrae 601, 602 together, such as the-posterolateral fusion and screw placement described above. This type of operation traditionally results in much blood loss because of the open access to the spine required for its performance. Utilizing the cannula 10 and support apparatus 110 for placement of the fixation assembly 620 at the surgical site and attachment of the fixation assembly 620 to the vertebrae 601, 602 in a manner to be described results in a much less invasive procedure and significantly less blood loss.
The cannulae 10 and the shrink wrap 102 are then removed from the body and the incisions are suitably closed. After a time, vertebrae 601, 602 and bone graft will grow together across the fusion cage(s) and in and around the fixation elements 650. The vertebrae 601, 602 will-then no longer require the fixation assembly to maintain their position. The fixation elements 650 and fasteners 624 may then be removed. The removal procedure may utilize the same type of apparatus as was used in the first and second procedures (i.e., cannula, support apparatus, etc.).
The inner tube 740 rotates about the axis 712 relative to the outer tube 750 within the outer tube. The inner tube 740 rotates in opposite directions a predetermined amount equal to one or more revolutions about the axis 712., then rotates in the opposite direction the same predetermined amount. Thus, the inner tube 740 oscillates about the axis 712. As the inner tube 740 oscillates/rotates about the axis 712, the cutting teeth 745, 755 on the inner and outer tubes 740, 750 cut tissue. Alternatively, the inner tube 740 may rotate in one direction (clockwise or counterclockwise) within the outer tube.
Another embodiment of the cannula or expandable conduit for use in a method in accordance with the present invention is illustrated in FIGS. 33-37 and is designated by reference number 1020. The expandable conduit 1020 includes a proximal wall portion 1022, which has a tubular configuration, and a distal wall portion, which is an expandable skirt portion 1024. The skirt portion 1024 is expandable from a reduced profile configuration having an initial dimension 1026 and corresponding cross-sectional area (illustrated in FIG. 33), to an enlarged configuration having a dimension 1028 and corresponding cross-sectional area (illustrated in FIG. 35). The skirt portion 1024 may be attached to the proximal cylindrical tube portion 1022 with a rivet 1030, pin, or similar connecting device to permit movement of the skirt portion 1024 relative to the proximal cylindrical tube portion 1022.
The skirt portion 1024 is manufactured from a resilient material, such as stainless steel. The skirt 1024 is manufactured so that it normally assumes an expanded configuration illustrated in FIG. 35. As illustrated in FIG. 34, the skirt portion 1024 may assume an intermediate dimension 1034 and corresponding cross-sectional area, which is greater than dimension 1026 of the reduced profile configuration of FIG. 33, and smaller than dimension 1028 of FIG. 35. Skirt portion 1024 may assume the configuration of FIG. 34 when deployed in the patient in response to the force of the tissue acting on the skirt portion. The actual dimension 1034 will depend upon several factors, including the rigidity of the skirt portion 1024, the surrounding tissue, and whether such surrounding tissue has relaxed or tightened during the course of the procedure. An outer plastic sleeve 1032 (illustrated in dashed line in FIG. 33) may be provided which surrounds the expandable conduit 1020 and maintains the skirt 1024 in the reduced profile configuration. The plastic sleeve 1032 may have a braided polyester suture embedded within it (not shown), aligned substantially along the longitudinal axis thereof; such that when the suture is withdrawn, the sleeve 1032 is torn, which allows the expandable conduit 1020 to resiliently expand from the reduced profile configuration of FIG. 32 to the expanded configurations of FIGS. 34-35. While in the reduced profile configuration of FIG. 33, the skirt portion 1024 defines a first overlapping configuration 1033, as illustrated by the dashed line. As the skirt portion 1024 resiliently expands, the skirt portion assumes the second configuration 1035, as illustrated in FIGS. 34-35.
The skirt portion 1024 is sufficiently rigid that it is capable of displacing the tissue surrounding the skirt portion as it expands. Depending upon the resistance exerted by surrounding tissue, the skirt portion 1024 is sufficiently rigid to provide some resistance against the tissue to remain in the configurations of FIGS. 34-35. Moreover, the expanded configuration of the skirt portion 1024 is at least partially supported by the body tissue of the patient. The rigidity of the skirt portion 1024 and the greater expansion at the distal portion creates a stable configuration that is at least temporarily stationary in the patient, which frees the physician from the need to actively support the conduit 1020 until the endoscope mount platform 1300 and support arm 1400 are subsequently added (see FIGS. 52-53).
As discussed above, the skirt portion 1024 is attached to the proximal cylindrical portion 1022 with a pivotable connection, such as rivet 1030. A pair of rivet holes 1036 are provided in the skirt portion 1024 to receive the rivet 1030. The two free ends 1038 and 1040 of the skirt portion 1024 are secured by a slidable connection, such as second rivet 1044 (not shown in FIG. 36, illustrated in FIGS. 33-35). A pair of complementary slots 1046 and 1048 are defined in the skirt portion 1024 adjacent the end portions 1038 and 1040. The rivet 1044 is permitted to move freely within the slots 1046 and 1048. This slot and rivet configuration allows the skirt portion 1024 to move between the reduced profile configuration of FIG. 33 and the expanded configuration of FIGS. 34-35. The use of a pair of slots 1046 and 1048 reduces the risk of the “button-holing” of the rivet, i.e., a situation in which the opening of the slot becomes distorted and enlarged such that the rivet may slide out of the slot, and cause failure of the device. However, the likelihood of such occurrence is reduced in skirt portion 1024 since each of the slots 1046 and 1048 in the double slot configuration has a relatively shorter length than a single slot configuration, which thereby limits the ability of the respective slots 1046 and 1048 to be distorted to the extent in which a rivet may slide out of position. In addition, the configuration of rivet 1044 and slots 1046 and 1048 permits a smooth operation of enlarging and reducing the skirt portion 1024, and allows the skirt 1024 to expand to span as many as three vertebrae, e.g., L4, L5, and S1, to perform a multi-level fixation.
As illustrated in FIG. 35, the skirt 1024 may be expanded to a substantially conical configuration having a substantially circular or elliptical profile. Alternatively, features may be provided on the skirt which facilitate the bending of the skirt at several locations to provide a pre-formed enlarged configuration. For example, in another embodiment of the cannula or expandable conduit 1070, illustrated in FIGS. 38-40, skirt portion 1074 may have four sections 1076 a, 1076 b, 1076 c, 1076 d having a reduced thickness. For a skirt portion 1074 having a thickness 1078 of about 0.007 inches thick, reduced thickness sections 1076 a, 1076 b, 1076 c, 1076 d may have a thickness 1080 of about 0.002-0.004 inches (FIG. 39). The width of the reduced thickness sections 1076 a, 1076 b, 1076 c, 1076 d may be about 1-5 mm. The thickness 1078 of the skirt portion 1074 may be reduced by milling or grinding, as is known in the art. Thus when the skirt 1074 is opened, it moves toward a substantially rectangular configuration, subject to the resisting forces of the body tissue (FIG. 40). Alternatively, another embodiment of the skirt (not shown) may be provided with two reduced thickness sections (rather than the four reduced thickness sections of skirt 1074) which would produce a substantially “football”-shaped access area.
In another embodiment of the cannula or expandable conduit 1080, the skirt portion 1084 is provided with a plurality of perforations 1086, in order to increase flexibility at the desired locations (FIGS. 41-43). The size and number of perforations 1086 may vary Depending upon the desired flexibility and durability. Alternatively, the skirt may be scored or otherwise provided with a groove or rib in order to facilitate the bending of the skirt at the desired location.
An early stage in the process is to determine the access point in the skin of the patient to insert the access conduit. In the exemplary embodiment, the access point corresponds to the posterior-lateral aspects of the spine. Manual palpation and Anterior-Posterior (AP) fluoroscopy may be used to determine the optimal incision locations. For the exemplary procedure, placement of the cannula or expandable conduit 1020 is preferably midway (in the ceph-caud direction) between the L4 through S1 vertebrae, centrally about 4-7 cm from the midline.
In addition to expanding the expandable conduit, the expander apparatus may also be used to position the distal portion of the expandable conduit at the desired location for the surgical procedure. The expander engages the interior wall of the expandable conduit, and moves the cannula to the proper location. For the embodiments in which the distal portion of the expandable conduit is relatively movable with-respect to the proximal portion, the expander apparatus is useful to position the distal portion without substantially disturbing the proximal portion.
An endoscope mount platform 1300 and indexing arm 1400 provide securement of an endoscope 1500 on the proximal portion 1025 of access conduit 1020 for remotely viewing the surgical procedure, as illustrated in FIGS. 51-54. The endoscope mount platform 1300 also provides several functions during the surgical procedure. The endoscope mount platform 1300 includes a base 1302 that extends laterally from a central opening 1304 in a general ring-shaped configuration. For the physician who is primarily viewing the procedure by observing a monitor, the base 1302 provides an aid for the physician when inserting surgical instruments into the central opening 1304. For example, the size of the base 1302 provides visual assistance (as it may be observable in the physician's peripheral vision) as well as provides tactile feedback as the instruments are lowered towards the central opening 1304 and into the expandable conduit 1020.
The endoscope mount platform 1300 further provides a guide portion 1306, which extends substantially parallel to the longitudinal axis 1308 away from the central opening 1304. The base 1302 is typically molded as one piece with the guide portion 1306. The base 1302 and guide portion 1306 may be constructed as a suitable polymer such as polyetheretherketone (PEEK).
The guide portion 1306 includes a first upright member 1310 extending upward from the base 1302, and a second upright member 1312 extending upward from the base 1302. The upright members 1310 and 1312 each have a respective vertical grooves 1314 and 1315 for slidably receiving an endoscopic mount assembly 1318.
As illustrated in FIGS. 52-54, the endoscope mount platform 1300 is mounted to the support arm 1400. The support arm 1400, in turn, is mounted to mechanical support, such as mechanical support arm A, which is incorporated by reference in its entirety herein. The support arm 1400 rests on the proximal portion 1025 of the expandable conduit 1020. The support arm 1400 includes an indexing collar 1420, which is received in the central opening 1304 of the base 1302 of endoscope mount platform 1300. The indexing collar 1420 is substantially torroidal in section and has an outer peripheral wall 1422 and inner wall 1424 and a wall thickness 1426. The indexing collar further includes a flange 1428, which supports the indexing collar 1420 on the support arm 1400.
The indexing collar 1420 is mounted to the proximal portion of the expandable conduit 1020 and allows angular movement of the endoscope mount platform 1300 with respect thereto about the central axis 1308 (as indicated by arrow C in FIG. 52). The outer wall 1422 of the index collar 1420 includes a plurality of hemispherical recesses 1450 for receiving one or more ball plungers 1350 on the endoscope mount platform 1300 (indicated in dashed line.) This mount configuration permits the endoscope mount platform 1300, along with the endoscope 1500 to be fixed in a plurality of discrete angular positions. Further details of the support arm and indexing collar are described in U.S. patent application Ser. No. 09/491,808, filed Jan. 28, 2000, Application No. 09/821,297, filed Mar. 29, 2001, and application Ser. No. 09/940,402, filed Aug. 27, 2001.
The rod portion 1502 supports an optical portion (not shown) at a distal end 1508 thereof, which may define a field of view of about 105 degrees and a direction of view 1511 of about 25-30 degrees. An eyepiece 1512 is positioned at an end portion of the body portion 1504. The camera (not shown) is attached to the endoscope 1500 adjacent the eyepiece 1512 with a standard coupler unit. A light post 1510 supplies illumination to the surgical site at the distal end portion 1508. A preferred camera for use in the system and procedures described herein is a three chip unit that provides greater resolution to the viewed image than a single chip device.
FIGS. 57-61 illustrate an embodiment of a fusion device or spinal implant 2010 that is inserted between the adjacent vertebrae. The spinal implant 2010 is placed between adjacent vertebrae to provide sufficient support to allow fusion of the adjacent vertebrae, as shown in FIGS. 67 and 78. The spinal implants 2010 are preferably made from an allograft material.
The spinal implant 2010 (FIGS. 57-61) has a first end 2020 for insertion between the adjacent vertebrae V. The first end 2020 has a tapered surface 2022 to facilitate insertion of the implant between the adjacent vertebrae V. The surface 2022 defines an angle X of approximately 45° as shown in FIG. 60.
The spinal implant 2010 (FIGS. 57 and 58) has a second end 2030 that is engageable with a tool 2032 (FIG. 70) for inserting the implant between the adjacent vertebrae V. The tool 2032 has a pair of projections 2034, one of which is shown in FIG. 70, that extend into recesses 2036 and 2038 in the end 2030 of the implant 2010. The recesses 2036 and 2038 (FIGS. 57 and 58) extend from the second end 2030 toward the first end 2020. The recess 2036 (FIG. 60) is defined by an upper surface 2040 and a lower surface 2042 extending generally parallel to the upper surface 2040. The recess 2038 (FIG. 58) has a lower surface 2046 and an upper surface 2048 extending generally parallel to the lower surface 2046.
The implant 2010 (FIGS. 57-60) has an upper surface 2060, as viewed in FIGS. 57-60, for engaging the upper vertebra V. The implant 2010 has a lower surface 2062, as viewed in FIGS. 57-60, for engaging the lower vertebra V. The upper and lower surfaces 2060 and 2062 extend from the first end 2020 to the second end 2030 of the implant 2010 and parallel to the upper and lower surfaces 2040, 2042, 2046, and 2048 of the recesses 2036 and 2038. The upper surface 2060 has teeth 2064 for engaging the upper vertebra V. The lower surface 2062 has teeth 2066 for engaging the lower vertebra V. Although FIGS. 57 and 58 show four teeth 2064 and four teeth 2066, it is contemplated that any number of teeth could be used.
A pair of spinal implants 2010 may be placed bilaterally between the adjacent vertebrae V. The cannula or expandable conduit 1020.1 s inserted into the patient's body adjacent the vertebrae V. The skirt portion 1024 of the cannula 1020 is radially expanded to provide a working space adjacent the vertebrae V. Disc material between the vertebrae V is removed using instruments such as kerrisons, rongeurs, or curettes. A microdebrider may also be utilized to remove the disc material. An osteotome, curettes, and scrapers are used to prepare end plates of the vertebrae V for fusion. Preferably, an annulus of the disc is left between the vertebrae V.
Another embodiment of a fusion device or spinal implant 2110 is illustrated in FIGS. 62-66. The spinal implant 2110 is substantially similar to the embodiment disclosed in FIGS. 57-61. The implant 2110 is placed between the adjacent vertebrae V to provide sufficient support to allow fusion of the adjacent vertebrae, as shown in FIG. 69. The spinal implant 2110 is preferably made from an allograft material.
The spinal implant 2110 (FIGS. 62-66) has a first end 2120 for insertion between the adjacent vertebrae V. The first end 2120 has a tapered surface 2122 to facilitate insertion of the implant between the adjacent vertebrae V. The surface 2122 defines an angle Y of approximately 45° as shown in FIG. 66.
The implant 2110 (FIGS. 62-65) has an upper surface 2160, as viewed in FIGS. 62-65, for engaging the upper vertebra V. The implant 2110 has a lower surface 2162, as viewed in FIGS. 62-65, for engaging the lower vertebra V. The upper and lower surfaces 2160 and 2162 extend from the first end 2120 to the second end 2130 of the implant 2110 and parallel to the upper and lower surfaces 2140, 2142, 2146, and 2148 of the recesses 2136 and 2138. The upper surface 2160 has teeth 2164 for engaging the upper vertebra V. The lower surface 2162 has teeth 2166 for engaging the lower vertebra V. Although FIG. 63 shows four teeth 2164 and four teeth 2166, it is contemplated that any number of teeth could be used.
The apparatus or shield 3100 for use in placing the fusion devices or spinal implants between the vertebrae is illustrated in FIGS. 71-75. The apparatus 3100 includes an elongated body portion 3102, which protects the nerve root or dura, and a mounting portion 3104, which allows for the surgeon to releasably mount the apparatus 3100 to the cannula 1020. Consequently, the surgeon is able to perform the surgical procedures without requiring the surgeon or an assistant to continue to support the apparatus 3100 throughout the procedure, and without reducing the field of view.
To install the apparatus 3100 within the interior passage of the proximal wall portion 1022, the surgeon may apply an inwardly directed force on the ring portion 3120, thereby causing the ring portion to resiliently deform, as illustrated by dashed line and arrows B in FIGS. 77-78. The surgeon subsequently inserts the apparatus 3100 into the interior lumen of the proximal wall portion 1022 (as indicated by arrow C) to the position of ring portion 3104 illustrated in solid line in FIGS. 77-78. When the surgeon releases the finger grip portions 3122, the ring portion 3120 resiliently moves towards its undeflected configuration, thereby engaging the interior lumen of the proximal wall portion 1022. The mounting portion 3104 described herein has the advantage that it is easily removed and/or moved with respect to the conduit 1020 without disturbing the position of the conduit 1020 or any other instrumentation.
During certain surgical procedures, it may be useful to introduce crushed bone fragments or the fusion devices 2010 or 2110 to promote bone fusion. As illustrated in FIGS. 80-80 a, apparatus 3100 is useful to direct the implants into the space I between adjacent vertebrae V. As shown in the figures, the distal portion 3110 of the elongated body portion 3102 is partially inserted into the space I. The distal end portion 3110, is positioned between adjacent vertebrae V, and creates a partially enclosed space for receiving the implants or other material therein.
Another embodiment of the apparatus or shield is illustrated in FIGS. 81-82, and designated apparatus 3200. Apparatus 3200 is substantially identical to apparatus 3100, described above, with the following differences noted herein. In particular, distal end portion 3210 includes a pair of surfaces 3240 and 3242. Surface 3240 is an extension of elongated shield portion 3202, and surface 3242 extends at an angle with respect to surface 3240. In the exemplary embodiment, surfaces 3240 and 3242 defined an angle of about 90 degrees between them. Alternatively another angle between surfaces 3240 and 3242 may be defined as indicated by the body structures to be protected.
As illustrated in FIGS. 83-84, distal end portion 3210 allows the apparatus to provide simultaneous shielding of both the dura D and the nerve root R. In FIGS. 83-84, surface 3242 shields the dura D, and surface 3240 shields the nerve root R. It is understood that surfaces 3240 and 3242 may be interchanged with respect to which tissue they protect during the surgical procedure.
A particularly useful fastener for use in the exemplary procedure is the fastener 4600, illustrated in FIGS. 85-86, and described in greater detail in U.S. patent application Ser. No. 10/075,668, filed Feb. 13, 2002 and application Ser. No. 10/087,489, filed Mar. 1, 2002, which are incorporated by reference in their entirety herein. Fastener 4600 includes a screw portion 4602, a housing 4604, a spacer member 4606, a biasing member 4608, and a clamping member, such as cap screw 4610. The screw portion 4602 has a distal threaded portion 4612 and a proximal, substantially spherical joint portion 4614. The threaded portion 4612 is inserted into the hole 4092 in the vertebrae, as will be described below. The substantially spherical joint portion 4614 is received in a substantially annular, part spherical recess 4616 in the housing 4604 in a ball and socket joint relationship (see also FIG. 88).
The fastener 4600 is inserted into the expandable conduit 1020 and guided to the prepared hole 4092 in the vertebrae as a further stage of the procedure. The fastener 4600 must be simultaneously supported and rotated in order to be secured in hole 4092. In the exemplary embodiment, the fastener 4600 is supported and attached to the bone by an endoscopic screwdriver apparatus 4660, illustrated in FIGS. 87-88. Screwdriver 4660 includes a proximal handle portion 4662 (illustrated in dashed line), an elongated body portion 4664, and a distal tool portion 4666.
In the exemplary embodiment, the guide apparatus 4800 has a proximal handle portion 4802, an elongated body portion 4804, and a distal tool portion 4806. The elongated body portion 4804 defines a central bore 4808 (illustrated in dashed line) along its longitudinal axis 4810. The central bore 4808 is sized and configured to receive the endoscopic screwdriver 4660 and cap screw 4610 therethrough. In the exemplary embodiment, the diameter of the central bore 4808 of the elongated body portion 4804 is about 0.384-0.388 inches in diameter, and the external diameter of the endoscopic screwdriver 4660 (FIG. 87) is about 0.25 inches. The proximal handle portion 4802 extends transverse to the longitudinal axis 4810, which allows the physician to adjust the guide apparatus 4800 without interfering with the operation of the screwdriver 4660.
The distal tool portion 4902 may also include a spacing member, such as spacing member 4906, which engages an adjacent fastener 4600 b while driver member 4904 is-engaged with housing 4600 a to move the fastener 4600 b with respect to fastener 4600 a. In the exemplary embodiment, spacing member 4906 is a jaw portion which is pivotably mounted to move between a first position adjacent the driver portion and a second position spaced from the driver portion, as shown in FIG. 95. The distal tip 4910 of the spacing member 4906 is movable relative to the driver portion 4904 in a direction extending transverse to the longitudinal axis.
with the elongated apparatus mounted inside the access device, then inserting at least a first fusion device through the access device, and inserting the fusion device between first and second vertebrae.
2. The method of claim 1, further comprising inserting a second fusion device through the access device, while maintaining the position of the access device, inserting the second fusion device between the first and second vertebrae, wherein the first and second fusion devices are positioned bilaterally between the adjacent vertebrae.
3. The method of claim 1, wherein the proximal region of the elongated apparatus is resilient and the step of mounting the elongated apparatus includes compressing the proximal region, inserting the elongated apparatus into the access device such that the distal region extends distally from the access device to cover the body structure, and releasing the proximal region to secure the proximal region of the elongated apparatus within the proximal portion of the access device.
4. The method of claim 3, wherein the proximal region of the elongated apparatus has an exterior shape corresponding to an interior shape of the access device, the proximal region having an opening, wherein the step of compressing the proximal region reduces the size of the opening, and the step of releasing the proximal region allows the opening to return to its original size, thereby engaging the access device.
5. The method of claim 4, wherein the exterior shape is a deformable partial ring biased in an open configuration, wherein the step of compressing the proximal region includes compressing ends of the ring.
6. The method of claim 1, wherein the body structure is a nerve root, and the elongated apparatus is inserted through the access device until the distal region covers the nerve root while exposing a disc between the first and second vertebrae.
7. The method of claim 1, wherein the elongated apparatus is inserted to a first position in which the distal region covers the body structure, wherein the distal end does not substantially displace the body structure.
8. The method of claim 7, further comprising moving the elongated apparatus to a second position within the access device in which the distal region covers another body structure.
9. The method of claim 1, wherein the distal region of the elongated apparatus includes first and second surfaces extending away from each other, wherein the elongated apparatus is positioned such that the first and second surfaces cover first and second body structures.
10. The method of claim 1, further comprising the step of expanding the distal portion of the access device after the distal portion is adjacent the at least one vertebra.
11. The method of claim 1, wherein the mounting step includes mounting the elongated device inside the access device such that the distal region extends at least partially into a space between the first and second vertebra.
without removing the access device, moving the elongated apparatus to a second position within the access device in which the distal region covers a second body structure.
13. The method of claim 12, wherein the access device is configured to move between an unexpanded configuration to an expanded configuration wherein in the expanded configuration a cross-sectional area of the access path at a first location is greater than a cross-sectional area of the access path at a second location, wherein the first location is distal to the second location.

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