STABILIZING RETRACTOR SYSTEM
20240148372 ยท 2024-05-09
Inventors
- Alidad Ghiassi (Los Angeles, CA, US)
- Steven Howard (La Jolla, CA, US)
- Bradley Klos (Solana Beach, CA, US)
- Michael Bauschard (Richmond, VA, US)
Cpc classification
International classification
A61B17/02
HUMAN NECESSITIES
A61B17/17
HUMAN NECESSITIES
Abstract
A soft tissue retraction system may include a support body. A soft tissue retraction system may include a bone engaging concavity on a first side of the support body. A soft tissue retraction system may include a soft tissue retracting surface on a second side of the support body. The system may include a first guide configured to receive a first pin to anchor the first pin into a bone when the bone is positioned within the bone engaging concavity. The system may include a second guide configured to receive a second pin to anchor the second pin into the bone when the bone is positioned within the bone engaging concavity.
Claims
1. A soft tissue retraction system, comprising: a soft tissue retractor, comprising: a support body; a bone engaging concavity on a first side of the support body; a soft tissue retracting surface on a second side of the support body; a first guide configured to receive a first pin to anchor the first pin into a bone when the bone is positioned within the bone engaging concavity; and a second guide configured to receive a second pin to anchor the second pin into the bone when the bone is positioned within the bone engaging concavity.
2. The system of claim 1, wherein the soft tissue retraction system is configured to apply axial compression when the first pin is received within the first guide and anchored into the bone and the second pin is received within the second guide and anchored into the bone.
3. The system of claim 1, wherein the soft tissue retraction system is configured to provide rotational translation when only one of the first pin and the second pin is received within its respective guide and anchored into bone.
4. The system of claim 1, wherein the bone is an ulna, a humerus, a metacarpal, a metatarsal, a fibula, a tibia, a femur, or a clavicle.
5. The system of claim 1, wherein the first guide comprises a first lumen and the second guide comprises a second lumen, wherein the first pin extends through the first lumen and second pin extends through the second lumen to anchor to the bone.
6. The system of claim 1, wherein the soft tissue retractor is configured to hold a reduction of the bone in place.
7. The system of claim 1, further comprising a window configured to receive a bone clamp when the bone is positioned within the bone engaging concavity.
8. The system of claim 1, further comprising a backing plate.
9. The system of claim 8, wherein the backing plate has a concave side configured to conform to an anatomy of a user, wherein the backing plate has a convex side opposite the concave side.
10. The system of claim 9, wherein the backing plate comprises a curved distal region comprising a concave side and a convex side and a proximal region having a different curvature than the distal region.
11. The system of claim 10, wherein the curved distal region is configured to support a palm and the proximal region is configured to support a forearm.
12. The system of claim 11, wherein the backing plate comprises a middle region connecting the proximal region and the curved distal region, wherein the middle region is configured to support a wrist.
13. The system of claim 1, further comprising a tie configured to couple to the soft tissue retractor.
14. The system of claim 13, wherein the soft tissue retractor is a first soft tissue retractor, wherein the system further comprises a second soft tissue retractor including a second bone engaging concavity configured to engage the bone, wherein the tie is configured to couple to the second soft tissue retractor to connect the first and second soft tissue retractors.
15. The system of claim 14, wherein the tie is configured to apply tension to pull a proximal end of the first soft tissue retractor and a proximal end of the second soft tissue retractor away from each other to retract opposing sides of an incision.
16. The system of claim 14, wherein the tie is an elastic tie.
17. A method of treating a fracture, comprising: engaging a bone engaging concavity of a soft tissue retractor with a bone, the soft tissue retractor comprising a support body having the bone engaging concavity on a first side of the support body and a soft tissue retracting surface on a second side of the support body; advancing a first pin through a first guide of the soft tissue retractor to anchor the first pin into the bone; and advancing a second pin through a second guide of the soft tissue retractor to anchor the second pin into the bone.
18. The method of claim 17, wherein the soft tissue retractor is configured to apply axial compression when the first pin is received within the first guide and anchored into the bone and the second pin is received within the second guide and anchored into the bone.
19. The method of claim 17, further comprising, prior to advancing the second pin through the second guide, applying rotational translation to the bone using the soft tissue retractor while the first pin is anchored within the bone.
20. The method of claim 17, wherein the bone is an ulna, a humerus, a metacarpal, a metatarsal, a fibula, a tibia, a femur, or a clavicle.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0053] The stabilizing retractor system of the present invention enables a surgeon to place a joint or limb in a pre-determined position, retract tissue from an incision site, and stabilize the retractors by securing them to an adjacent bone. This eliminates the need for additional clinical personnel to hold the retractors. Although the system described herein can be readily adapted to other surgical procedures throughout the body, it will be detailed herein primarily in the context of wrist or hand surgery as an example. The invention can be readily expanded to multiple other areas with elbow, shoulder, knee, ankle (Tibia and Fibula), spine, pelvis, and hip surgery being of particular emphasis.
[0054] In the context of a wrist surgery, the stabilized retractors also allow the surgeon to manipulate the wrist and location of an implant into a desired orientation, and move the wrist into and out of an X-ray field of view while maintaining the relative orientation of the wrist and of the implant relative to adjacent bone. This enables fine adjustments to the implant based upon the X-ray image since the orientation of the wrist and implant is maintained by the stabilized retractors.
[0055] The system may be constructed of radiolucent plastic components that can be fabricated through 3D printing or other more traditional methods like injection molding or thermo-forming. Components may be packaged for a single patient procedure and pre-sterilized. Components may be single use only and disposable. Components sizes may vary based on areas of the body (e.g., elbow, shoulder, knee, ankle (Tibia and Fibula), spine, pelvis, and hip).
[0056] During the surgical procedure, the clinician will position a primary support shell underneath the limb or joint to be accessed. The clinician will make an incision and then utilize a first and second opposing retractors retract the tissue. The retractors are next fixed with respect to adjacent bone to maintain the retracted tissue. Fixation may be accomplished by pinning each retractor to the radius using at least one pin (e.g., an attachment pin, threaded pin, non-threaded pin, or K-wire) per retractor.
[0057] It is likely that each system will thus include 1 support shell and 2 retractors. Each system may be configured with more components based upon customization. The additional components may include, for example, wire or wraps to secure the retractors adequately to the patient, and one or more elastic ties to secure the retractors to the support shell. The components may have attachment anchor guides such as holes and slots as necessary to allow for complementary attachment anchors or attachment to other components.
[0058] Customization for use in complicated cases may occur by 3D printing of parts based upon scanned image data on a patient by patient basis. Customization could also be more generic to a particular surgical procedure.
[0059] Conventional retractors are metallic and therefore impervious to X-ray imaging. This has impact to the Clinician, the assistant, and the patient. The clinician routinely risks chronic exposure to radiation through repeated exposure of hands, neck, and eyes during examination of the patient. The assistant has similar risk of exposure of radiation to the body (e.g., hands, neck, and eyes). Routinely, the assistant and clinician will remove the retractors so that imaging of the reduced bone union and implants can be clearly seen. When the retractors are removed, the clinician or assistant must insert their hands into the x-ray field to try to keep the fracture stable. Maintaining the union stable is not always achieved, potentially requiring additional repositioning and imaging steps. Also, with repeated insertion and removal of the retractors, there is increased risk to nerve and tendons that are repeatedly stretched and manipulated by rigid metallic retractors.
[0060] Referring to
[0061] A stabilizing retractor system 16 in accordance with the present invention is illustrated as mounted to the radius 10. Surrounding soft tissue has been omitted for clarity, however the retractor system 16 will be utilized to separate opposing soft tissue sides of a surgical cut down to expose the radius 10 as is understood in the art.
[0062] The system 16 includes a first retractor 18 and a second complementary retractor 20. The second retractor 20 may be a mirror image and/or have similar functionality to the first retractor 18, so primarily only a single retractor will be described in detail.
[0063] Retractor 18 comprises a support 22 such as a contoured plate, which will be described in greater detail below. In general, the support 22 includes a radius engaging surface 24 on a first side of the support 22, and a soft tissue retracting surface 26 on a second, opposite side of the support from the radius engaging surface 24. The retractor may be characterized as having a long axis and a transverse short axis.
[0064] Support 22 additionally comprises a guide 28 defining a lumen 30 for axially movably receiving an attachment pin 29 (e.g., a K wire, threaded fixation device, or non-threaded fixation devices) for securing the support 22 to the radius 10. The lumen 30 may extend directly through the support 22, or extend through a separate guide structure 32 carried by the support 22. The lumen 30 may be oriented to receive the K wire along a path that is substantially perpendicular to the adjacent surface of the radius 10 in the as mounted orientation. The axis of the guide 28 is generally within about 20 degrees, in many implementations within about 15 degrees or 10 degrees or less of parallel to the long axis. In the illustrated configuration, the guide 28 is substantially parallel to the long axis.
[0065] The retractor system may additionally comprise a backing plate 34, for positioning on the opposite side of the wrist from the incision. The backing plate may comprise an elongate arcuate body 36 having an (anatomically as used) proximal end 38, a distal end 40, and an elongate concavity 42 for receiving the wrist.
[0066] A convex side of the body 36 may be provided with a forceps landing zone 44, comprising a plurality of recesses 46 for receiving a forceps prong 48 as shown in
[0067] The system 16 may additionally include a drill guide 50 (or a targeting guide) having a proximal handle 52 and a distal guide 54. The guide 54 includes a guide path such as a lumen 56 for receiving a drill or pin (e.g., an attachment pin, threaded pin, non-threaded pin, or K-wire) (not illustrated).
[0068] Each of the first retractor 18 and second retractor 20 may be provided with a connector 60, 62, respectively. The connector 60, 62 may comprise an aperture, post, snap or other connector for receiving a tie to connect to the backing plate 34. The tie may be elastic, and mounted under tension to place a radially outwardly bias on the connectors 60, 62 to maintain the soft tissue in the retracted orientation. In one implementation of the invention, a single elastic tie may be attached to a first connector, extended around the back of the backing plate, tensioned, and attached to the second connector.
[0069] Additional details of a backing plate 34 suited particularly for the wrist are illustrated in
[0070] Additional details of a soft tissue retractor are illustrated in
[0071] The radius engaging surface 24 is provided near the distal end 72, and is separated axially from the soft tissue retention surface 26 by an inflection 84. The soft tissue retention surface 26 may be provided with a greater width than the width of the radius engaging surface 24. In the illustrated implementation, radius engaging service 24 is provided on a projection 86 extending distally beyond the distal end of the guide structure 32, and having a maximum width of no more than about 70%, or no more than about 50% or less of the width of the soft tissue retention surface 26. The width of the projection tapers smaller in a distal direction to a rounded tip 88 which is spaced apart laterally from the longitudinal axis of the lumen 30.
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[0075] The proximal portion of the retractor (see, e.g.,
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[0078] As shown in
[0079] As shown in
[0080] As further shown in
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[0083] As shown in
[0084] As further shown, in
[0085] In some embodiments, for example, as shown with respect to
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[0087] As shown in
[0088] In some embodiments, each retractor 161 (e.g., two retractors 161) can include a window 163 in a body 164 of the retractor 161 that may allow for positioning of the bone clamp to further help with the reduction (e.g., by providing additional stabilization). The window 163 can be sized and configured to allow a user to position a device through the window 163. For example, at least a portion of the bone clamp 155 can extend through the window 163 (e.g., the window 163 on each retractor 161). The windows 163 may enable access to the bone (e.g., the humerus) without impeding the retractor 161. In some embodiments, multiple clamps may be used with the retraction and stabilization system. The retractor 161 can have a bone engaging surface 167 (e.g., on or adjacent to the body 164) and a tissue engaging surface 168 on the opposite side of the retractor 161. The bone engaging surface 167 can be on a distal end of the retractor 161.
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[0090] As shown in
[0091] While the embodiment of each retractor 161 shown in
[0092] In some embodiments, each retractor 161 (e.g., two retractors 161) can include a window in a body 164 of the retractor 161 that may allow for positioning of the bone clamp to further help with the reduction (e.g., by providing additional stabilization). The window can be sized and configured to allow a user to position a device through the window. For example, at least a portion of the bone clamp 155 can extend through the window. The windows may enable access to the bone (e.g., radius 10) without impeding the retractor 161. In some embodiments, multiple clamps may be used with the retraction and stabilization system. The retractor 161 can have a bone engaging surface (e.g., on or adjacent to the body 164) and a tissue engaging surface on the opposite side of the retractor 161 as described herein. The bone engaging surface can be on a distal end of the retractor 161.
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[0094] Various embodiments of the backing plates described herein can have different shapes and configurations to allow a closer anatomical match to and/or provide support to the patient's anatomy. For example, various embodiments of the backing plates described herein may have different lengths, widths, curvatures, etc., at different sections of the backing plate to support different regions of the patient's anatomy. For example, various embodiments of the backing plates described herein can be concave and convex surfaces that follow the natural anatomy of the patient.
[0095] As shown in
[0096] In certain embodiments, the backing plate 151 can include a proximal region 109. The proximal region 109 can be configured to correspond to (e.g., match) the anatomy of the forearm. In some embodiments, the proximal region 109 can also be configured to correspond to (e.g., match) the anatomy of at least a portion of the wrist of the patient. The proximal region 109 can be generally flat or have less curvature than the distal region 101. The proximal region 109 can have a smooth surface. The wings 107 of the distal region 101 may extend laterally beyond the edges of the proximal region 109. In some embodiments, the wings 107 may extend partially beyond or entirely beyond the bones (e.g., metacarpal bones) of a user. The proximal region 109 can have a convex side 103 and a concave side 105.
[0097] In certain embodiments, the backing plate 151 can include a middle region 111 positioned between the proximal region 109 and the distal region 101. The middle region 111 can be configured to correspond to (e.g., match) the anatomy of the wrist. The middle region 111 may be flat or have less curvature than the distal region 101. In some embodiments, the middle region 111 can allow for a linear transition from the distal region 101 to the proximal region 109. Alternatively, the middle region 111 can allow for a curvilinear transition from the distal region 101 to the proximal region 109. The proximal region 109 can have a narrower width than the distal region 101.
[0098] In some embodiments, the backing plate 151 may be temporarily fixed to a patient's body after surgery, much like a split. The backing plate 151 can be applied in order to protect the wound and joint from being bumped or unintentionally moved which may result in damage to the surgical site. An elastic tie, such as elastic tie 165, can wrap around the backing plate 151 to secure the backing plate 151 to the patient's body when the elastic tie is attached to the tissue retractors 161 (e.g., via connectors, such as connectors 141).
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[0107] In certain embodiments, one or more universal retractors 170 may be used as drill guides, for example, as described with respect to
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[0109] Procedure steps in an exemplary procedure are described below. Not all steps are necessary in a particular procedure, multiple images may be obtained depending on the nature of the fracture(s), and the order of performance of some of the steps can be varied as will be understood by those of skill in the art.
[0110] Take the Backing Plate out of the pouch.
[0111] Place Backing Plate on the patient's forearm.
[0112] Establish surgical access to the radius.
[0113] Take one of the Ulnar side retractors out of the pouch.
[0114] Drill the pin (e.g., an attachment pin, a threaded pin, a non-threaded pin, a K-wire, or a metallic rod) or other metallic fixation device at the desired angle using the handheld radiolucent drill guide.
[0115] Slide Ulnar side retractor passing the pin through the guide lumen into desired position. Ensure the tip is distal to the guide lumen. Alternatively, insert the ulnar side retractor first, securing the distal tip under the bone. Then insert the pin into the lumen and drill into the bone.
[0116] Take the Radial side retractor out of the pouch.
[0117] Drill the pin at the desired angle using the handheld radiolucent drill guide.
[0118] Slide Radial side retractor passing the pin through the guide lumen into desired position. Ensure the tip is distal to the guide lumen.
[0119] Secure both Ulnar, Radial, and Backing plate with rubber bands.
[0120] If more visualization of the lunate region is needed, use the retractor end of the handheld radiolucent drill guide as a retraction mechanism.
[0121] Place implant plate on the space between the two Ulnar fixed parts over the radius
[0122] Check where plate was placed relative to the fixed device parts.
[0123] Once implant plate is positioned, put some acumen pin (2 pins placed, using the handheld radiolucent drill guide), to hold the plate in position.
[0124] Clamp backing plate to the bone.
[0125] Place another pin (Trajectory pin).
[0126] Take imaging shot (Xray with contrast) to judge plate's position with respect to radial bone. Verify bone fragments are correctly positioned to ensure proper range of motion for the patient once healed.
[0127] Move the setup until obtaining a proper shot by grabbing onto the clamp.
[0128] Drive trajectory pin forward/backwards or change trajectory as needed.
[0129] Reposition the clamp accordingly to get a better view.
[0130] Repeat the shot as needed.
[0131] Remove pins.
[0132] Remove rubber bands.
[0133] Remove Ulnar and Radial parts.
[0134] Remove Backing plate.
[0135] Standard surgical closure.
[0136] Additional details of a variety of system components are illustrated in the attached Figures, with structural details of specific examples identified in the table below and associated with call out numbers in the drawings. All recited dimensions are related to specific embodiments, but any such recited dimension may be varied by +/?25% or +/?15% or other scaling depending upon the desired application and performance as will be understood by those of skill in the art. Method steps are also described below the feature table, below.
TABLE-US-00001 ID Feature Description Specification range 1 Wrist Base Curvature Curvature that Defined by four arc Backing matches the contour segments with radii plate of the forearm to allow 34, 44, 30, and 40 for arm resting on the mm. plate. 2 Side Cuts Two symmetric side Hourglass shaped cuts for matching Width of the plate at forearm shape and proximal end: 54.52 ensuring good support mm. and contact. Width of the plate at Cuts are symmetric distal end: 78.8 mm. for device to be used Width of the plate at for both left and right neck: 57.6 mm. arms. Cut: 40 mm width at proximal end 17.43 mm width at distal end 3 Distal wings Optimized degree of 144? of coverage radial/ulnar coverage. (wing-to-wing) in one implementation; generally within the range of from about 90 to 180 degrees 4 Length Optimal length to 160 mm. provide good structural support of forearm. 5 Fillet Fillet corners to Radius of 10 mm at smooth the edges distal, 8 mm at No sharp surfaces to proximal end, and 1 irritate patient skin or mm throughout. represent sharp points for gloves. 6 Grid pattern Covering the distal Rectangular pattern end, to improve the with 1 mm depth and grip and allow for contoured pockets; tunable clamp grid size may be from placement. about 0.5 to about 2.0 mm 7 Thickness Optimal thickness to At proximal end: 3 decrease bulkiness mm while ensuring At distal end: 4 mm; stiffness and strength both generally within the range of from about 1 mm-4 mm 8 Material Nylon 12 could Tensile Modulus: ultimately have 0 MPa composite Tensile Strength: 48 reinforcement MPa Flexural/Bending Modulus (23? C.): 1,500 MPa 9 Scale Scaled to 0.8 on x and Scaling factor: 0.8 y axes for small size 10 Ulnar Base Profile Curved handle Defined by two 60? Plate extending laterally arcs with radii 25 mm (Left & away from the incision and 28.3 mm, Right) site so surgeons view respectively. 20 mm is un-obstructed. long rectangular tail Length extended and 0.8 mm thick beyond wrist to create pointy end. appropriate vector for elastic restraints 11 Tip Tip created by a cut at Width: 15.78 mm the distal end. For Height: 11.5 mm better attachment of Fillet of 1.75 mm the plate within the radius. bony structures. Offset from centerline of plate for torsional adjustments Geometry provides leverage 12 Rib Cylindrical Rib Rib diameter: 6 mm structure appended on Inner hole diameter: opposite side of the 2.2 mm tip, with an inner hole Rib Length: 25 mm for pin placement Chamfer: 0.5 mm to secure the plates by distance and 45? drilling into the bone. Offset from centerline to aid in placement and rotation 13 Rounded corners at To improve flexibility, 9 mm radius. proximal end reduce bulkiness and smooth the edges. 14 Center cut To improve flexibility 23.05 mm radius when surgeon handles 35 mm cut length and fixates the plate at Fillets of 6 and 8 mm different positions. of radius at edges of Narrow neck to reduce center cut. the impact to incision length 15 Thickness Not too thick to avoid 3.3 mm in one bulkiness nor too thin implementation; so that it is too fragile generally within the range of from about 1-4 mm 16 Hook Located at the 12 mm wide, 8.6 mm proximal end. To long hook over 18.9 enable elastic band mm wide, 13.6 mm attachment. long gap. Radius of Hook arcs: 2.5 mm and 1.5 mm 17 Material Nylon 12 could Tensile Modulus: ultimately have 1620 MPa composite Tensile Strength: 48 reinforcement MPa Flexural/Bending Modulus (23? C.): 1,500 MPa 18 Lunate Tip Curved shape and flat Two 60? arcs with Retractor/ end for optimal tissue radii 32 mm and 25 Drill contact without mm. Guide impingement risk Variable thickness: from 3.25 to 5.25 mm. Two 7.5- and 10-mm radii arcs at the distal end of the tip. 19 Cut-out Cut-outs on sides of Cut-outs of 10.25- tip to confer hourglass and 15-mm radii shape along length of tip. Width at proximal end: 16 mm Width at distal end: 14.49 mm 20 Fillet Fillet corners to 3 of radius smooth the edges surrounding entire No sharp surfaces to part irritate patient skin or represent sharp points for gloves. 21 Loft Neck of the handle Rectangular to oval shape. Loft constraint by two 40- and 70-mm radii arcs. 22 Rib Rib cylindrical Rib radius: 3.25 mm structure appended on cylindrical rib of same side of the length 32.5 mm Inner retraction end, with an hole radius: 1.10 mm inner hole for pin Chamfer: 0.5 mm placement to secure distance and 45? the plates by drilling into the bone. 23 Extrusion Extrusion to increase Length 52 mm in one the length of the implementation; retractor end generally from about 40-80 mm 24 Handle Hole left that acts as 25-mm long, 6.5-mm handle for improved wide cut with the grip and potential shape of a slot in one interface with elastic implementation; restraints length generally from about 20-50 mm 25 Fillet Fillets along the rib for 0.5-mm fillets at smoothing purposes. chamfer No sharp surfaces to 1 mm fillet along irritate patient skin or length of the rib represent sharp points for gloves. 26 Fillet Fillets at the distal end Radius 1 mm along and handle for tip width. smoothing purposes. Radius 2 mm along No sharp surfaces to handle irritate patient skin or represent sharp points for gloves. 27 Duality Dual device useful for both tissue retraction and as a drill guide for pin insertion 28 Ankle Base Curvature Curvature that Defined by four arc Backing matches the contour segments with radii Plate of the _ to allow for _ 50, 54, 37.5, and resting on the plate. 41.5 mm. 29 Side Cuts Two symmetric side Hourglass shaped cuts for matching _ Width of the plate at shape and ensuring proximal end: 54.05 good support and mm. contact. Width of the plate at Cuts are symmetric distal end: 78.89 mm. for device to be used Width of the plate at for both left and right neck: 50 mm. legs. Cut: 40 mm width at proximal end 17.3 mm width at distal end 30 Distal wings Optimized degree of 144? of coverage tibial coverage. (wing-to-wing) 31 Length Optimal length to 160 mm. provide good structural support of _. 32 Fillet Fillet corners to Radius of 10 mm at smooth the edges distal, 8 mm at No sharp surfaces to proximal end, and 1 irritate patient skin or mm throughout. represent sharp points for gloves. 33 Grid pattern Covering the _end, to Rectangular pattern improve the grip and with 1 mm depth and allow for tunable contoured pockets clamp placement. 34 Thickness Optimal thickness to At proximal end: 3 mm decrease bulkiness At distal end: 4 mm while ensuring stiffness and strength 35 Material Nylon 12 could Tensile Modulus: ultimately have 1620 MPa composite Tensile Strength: 48 reinforcement MPa Flexural/Bending Modulus (23? C.): 1,500 MPa 36 Ankle Base Profile Curved handle Defined by two 60? side extending laterally arcs with radii 25 mm retractor away from the incision and 28.3 mm, site so surgeons view respectively. 20 mm is un-obstructed. long rectangular tail Length extended and 0.8 mm thick beyond ankle to create pointy end. appropriate vector for elastic restraints 37 Tips Two tips created, Width: 15.78 mm mirror images of each Height: 11.5 mm other, by a cut at the Fillet of 1.75 mm distal end. For better radius. attachment of the plate within the bony structures. Geometry provides leverage 38 Rounded corners at To improve flexibility, 9 mm radius. proximal end reduce bulkiness and smooth the edges. 39 Side Relieves Two center cuts on 22.5 mm radius each side. 35 mm cut length To improve flexibility Fillets of 5 mm of when surgeon handles radius at edges of and fixates the plate at center cut different positions. Narrow neck to reduce the impact to incision length 40 Thickness Not too thick to avoid 3.3 mm bulkiness nor too thin so that it is too fragile 41 Hook Located at the Tilted 25.5? outward. proximal end. To 16 mm wide, 15.2 enable elastic band mm long hook over attachment. 22 mm wide, 20 mm Slightly bend outwards long gap. to aid in rubber band Radius of Hook arcs: placement. 4 mm and 1 mm 42 Material Nylon 12 could Tensile Modulus: ultimately have 1620 MPa composite Tensile Strength: 48 reinforcement MPa Flexural/Bending Modulus (23? C.): 1,500 MPa 43 System Tightening mechanism Grid pattern improving grip for clamping at different locations. 44 Compatibility pins and clamps 45 Adjustability after anchoring Variable tensioning with elastic bands to easily adjust positions 46 Clinical Position verification Device made of Nylon which is radiolucent, position can be verified during fluoroscopy imaging. 47 Variants of location Different scales for different patient sizes. 48 Radiolucency Materials transparent to X-rays 49 Hands free Self-retaining mechanism via elastic bands and clamp placement 50 Permanent thru procedure Self-retaining mechanism via elastic bands and clamp placement