Bone depth gauge device

Abstract

A bone depth gauge device, comprising a body having a first body portion and a second body portion and comprising a lumen extending therethrough, an outer sleeve at least partially enclosing the body and configured to axially translate along the length of the body, a rod positioned within the lumen of the body, having a deployable tip positioned adjacent a distal end of the first body portion, and a lever coupled to a proximal end of the rod and configured to actuate a rotation of the rod, wherein the deploy able tip is deployed via laterally translating the deployable tip from a central axis of the first body portion via a rotation of the rod.

Description

[0001] BONE DEPTH GAUGE DEVICE

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application No. 63 / 656,664 filed on June 6, 2024, the contents of which are incorporated by reference herein in its entirety.

[0004] BACKGROUND

[0005] Traditional bone depth gauges are notoriously inaccurate tools, often used in head and neck surgery, that estimate the screw length needed for fracture fixation after bicortical drilling. Complications related to inaccurately sized screws may include soft tissue irritation or weakness of the repair and subsequent refracture.

[0006] Surgeons must often think creatively and consider new technologies and designs in the search for improved instrumentation. Novel improvements in traditional tool designs that benefit surgeon efficiency and patient outcomes play a critical role in equipping surgeons with the best tools for the task at hand. Bicortical drilling is a common surgical technique; it is seen in open reduction and internal fixation (ORIF) procedures to treat traumatic and iatrogenic fractures across many specialties and anatomical regions. (Robey AB, et al. Plast Reconstr Surg. 2008; 122(6): 1733-1738.; Roth JJ, et al. J Hand Surg Am. 2005;30(l): 151 - 153. ; Schmiddem U, et al. Knee Surg Sports Traumatol Arthrosc. 2019;27(l):239-244.) Surgeons stabilize fractures by selecting screws that expand through the marrow space to engage the distal cortex. (Roth JJ, et al. J Hand Surg Am. 2005;30(l): 151-153.; Gwinner C, et al. Int Orthop 2015;39(9): 1749-1755.) These are typically used to hold a rigid place over the area of the fracture. In the realm of head and neck surgery, bicortical drilling is commonly used in mandibular reconstruction, such as in oncological fibular free flaps, traumatic fractures, or iatrogenic osteotomies for mandibular correction. (Robey AB, et al. Plast Reconstr Surg. 2008; 122(6): 1733-1738.; Ellis E, et al. J Oral Maxillofac Surg. 2009;67(l 1):2528- 2533.; Ellis E, et al. J Oral Maxillofac Surg. 1991;49(3):234-243.; Frodel JL, et al. Arch Otolaryngol Head Neck Surg. 1993; 119(3):297-304.; Koenig ZA, et al. Craniofac Surg. 2024;35(2):649-651 .; Yamashita Y, et al. Int J Oral Maxillofac Surg. 2011 ;40(4):360- 365.)

[0007] Many surgeons have experienced the difficulty in using the available manual depth gauges needed for bicortical screw selection in ORIF cases. This old- fashioned tool uses a thin hook and rod that can be inserted into a drill hole with the intention of catching the distal cortex. A secondary measuring body is attached, allowing a user to obtain the measurement. Besides the diameter of the rod, the tool is similar across different drill sizes. This style of depth gauge can be found in the literature throughout the last century, and articles from decades prior report device warping and poor cortical catching. (Beaty NB, et al. Arch Otolaryngol Head Neck Surg. 2009;135(9):920-923.; Bradley JC. Br J Oral Surg. 1975;13(1): 100-101.; Gunther WA, et al. J Bone Joint Surg Am. 1948;30A(l):233.) As a result, inaccurate readings are possible.

[0008] Inaccurately sized screws can either be overestimated or underestimated, both causing serious complications for different reasons. An overestimated screw may cause tendinopathies and / or direct nerve and vascular injury. (Bouwman JP, et al. Br J Oral Maxillofac Surg. 1995; 33(4):231-234.; Clitherow HD, et al. 2014;8(4): 122-126.; Cook JB, et al. J Orthop. 2017;14(3):384-389.; Johnson B, et al. Cardiovasc Surg. 1996;4(3):414-415; Reddy AK, et al. Shoulder Elbow. 2022; 14(5):481 -490.; Sethi PM, et al. J Shoulder Elbow Surg. 2015;24(l): 138-142.) While serious injury to these neighboring structures is rare, protruding screws are more likely associated with worsened quality of life by causing localized irritation of the soft tissue and adjacent neurovasculature. (Bouwman JP, et al. Br J Oral Maxillofac Surg. 1995; 33(4):231-234.; Alic T, et al. Jt Dis Relat Surg. 2023;34(l): 108-114.; Butt U, et al. J Shoulder Elbow Surg. 2012;21(8): 1110-1119.; Posnick JC, et al. Int J Oral Maxillofac Surg.

[0009] 2016;45(l 1): 1445-1451.) An underestimated screw with a depth gauge would not reach the distal cortex of bone. This would lead to a weaker fracture repair. An underestimated screw would only have monocortical engagement, but its longer length relative to monocortical screws puts structures in the marrow space at risk without any added repair benefit. For example, a protruding screw may cause injury to the inferior alveolar nerve in the mandible without reaching the lingual cortex. (Yamashita Y, et al. Int J Oral Maxillofac Surg. 201 l ;40(4):360-365.; Bouwman JP, et al. Br J Oral Maxillofac Surg. 1995; 33(4):231-234.) Monocortical screws would not be effective unless additional plates and screws are used, and / or the diameter of the screw is increased. (Schmiddem U, et al. Knee Surg Sports Traumatol Arthrosc. 2019;27(l):239-244.; Yamashita Y, et al. Int J Oral Maxillofac Surg. 2011;40(4):360-365.; Ribeiro J, et al. Craniomaxillofac Trauma Reconstr. 2016;9(2): 105-108.) Bicortical screws remain the gold standard for many procedures, from femur fixation to shoulder Lateijet procedures to condylar fracture repair, therefore, ensuring accurate distal cortex engagement is crucial for surgeons. (Schmiddem U, et al. Knee Surg Sports Traumatol Arthrosc. 2019;27(l):239-244.; Gwinner C, et al. Int Orthop 2015;39(9): 1749-1755. Chung IH, et al. J Oral Maxillofac Surg. 2008;66(3):446-452.; Dayi E, et al. Ann Maxillofac Surg. 2011; l(l):48-52.;

[0010] Kosters C, et al. J Clin Med. 2022; 11(5): 1184.)

[0011] Recent studies by Liu et al. and Jernigan et al. used porcine femur and cadaveric phalangeal models to quantify surgeon accuracy and precision with current manual depth gauges. In these models, surgeons with varying years of experience struggled to use industry standard depth gauges, selecting both overestimated and underestimated screws. (Jernigan EW, et al. J Hand Surg Am. 2018;43(12): 1138. el- 1138. e8.; Liu P, et al. Front Surg. 2021;8:774682.) Overestimated screws protruded past 1.0mm in these models, and short screws failed to reach the trans cortex. Screw selection was poor after both straight and angled drilling, but angled drilling was associated with worse accuracy. More experienced users selected fewer short screws and their precision was improved compared to their less experienced counterparts; more experienced surgeons, however, had an overall accuracy in the 50% range. For less experienced surgeons, their accuracy was in the 30% range. (Jernigan EW, et al. J Hand Surg Am. 2018 ;43 ( 12) : 1138. e 1 - 1138. e8. ; Liu P, et al . Front Surg. 2021 ; 8 : 774682. )

[0012] There has been a call for surgeons to master proper screw selection with the current depth gauge design to mitigate long term complications, but new devices that incorporate updated features will be the better solution to improve hardware placement. (Rafique B, et al. Arch Plast Surg. 2017;44(4):356-357.) Progress has been made with electronic devices, such as using laser ranger finders, digital depth gauges, and a dual drill and depth sensor. (Demsey D, et al. Clin Orthop Relat Res. 2019;477(l 1):2579- 2585.; Lang SD, et al. Orthopedics. 2020;43(5):e465-e470.) The classic hardware, however, has not evolved significantly from its original design. A few modifications could guarantee distal cortex catching without it becoming stuck. Sticking of the device is a valid concern that would theoretically require additional dissection to dislodge it.

[0013] Thus there is a need in the art for a bone depth gauge device that can guarantee catching of the distal cortex while also incorporating an intra-operative disassembly mechanism to prevent sticking.

[0014] SUMMARY

[0015] Described herein is a bone depth gauge device, comprising a body having a first body portion and a second body portion and comprising a lumen extending therethrough, an outer sleeve at least partially enclosing the body and configured to axially translate along the length of the body, a rod positioned within the lumen of the body, having a deployable tip positioned adjacent a distal end of the first body portion, and a lever coupled to a proximal end of the rod and configured to actuate a rotation of the rod, wherein the deployable tip is deployed via laterally translating the deployable tip from a central axis of the first body portion via a rotation of the rod.

[0016] In some examples, the first body portion has a smaller width or diameter than the second body portion, wherein the first body portion is configured to be inserted into a hole whose depth is to be measured. In some examples, the deployable tip when undeployed has a diameter equal to the outer diameter of the first body portion. In some examples, the deployable tip when deployed forms a hook structure configured to engage a distal edge of a hole.

[0017] In some examples, the second body portion comprises markings indicating a depth measurement. In some examples, the outer sleeve comprises a tapered proximal edge and a distal bone stop. In some examples, the tapered proximal edge of the outer sleeve indicates a marking on the second body portion corresponding to a depth. In some examples, the markings are calibrated to a length of the first body portion extending between the deployable tip and the distal bone stop of the outer sleeve.

[0018] In some examples, the device is made of a rigid and biocompatible material chosen from the group consisting of metals, metal alloys, titanium, stainless steel, aluminum, plastics, and polymers. In some examples, the device has a length ranging between about 10 cm to 30 cm. In some examples, the device measures depths ranging between 0.1 mm and 100 mm. In some examples, the lumen extending through the first body portion is positioned off-center within the first body portion. In some examples, the first body portion has an outer diameter ranging between 1 mm and 5 mm. In some examples, the lumen of the first body portion has an outer diameter ranging between 0.5 and 3 mm. In some examples, the rod has an outer diameter ranging between 0.1 mm and 2.5 mm. In some examples, the minimum distance between the outer circumference of the first body portion and the outer circumference of the lumen of the first body portion ranges between 0.2 mm and 1 mm. In some examples, the maximum distance between the outer circumference of the first body portion and the outer circumference of the lumen of the first body portion ranges between 0.5 mm and 2.5 mm.

[0019] In some examples, the axial translation of the deployable tip causes a diameter or width increase of the distal end of the device ranging between 0.1 mm and 2.5 mm. In some examples, the device is assembled from component parts, wherein the component parts are configured to be easily disassembled. In some examples, the device is constructed from replaceable component parts. In some examples, the device is constructed from a combination of permanent and replaceable component parts.

[0020] Also described herein is a method of measuring the depth of a bone hole, comprising providing the bone depth gauge device, inserting the first body portion into a hole until the deployable tip extends past the distal edge of the hole, deploying the deployable tip via a rotation of the lever, engaging the distal edge of the hole via the deployable tip, advancing the outer sleeve until it contacts the bone surface, and reading an indicated marking on the second body portion to obtain a depth measurement.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following detailed description of embodiments of the invention will be better understood when read in conjunction with the appended drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities of the embodiments shown in the drawings. Fig. 1 A depicts a front-view of an exemplary bone depth gauge device. Fig. IB depicts a perspective view of the distal end of an exemplary bone depth gauge device with the tip deployed. Fig. 1C depicts a perspective view of an exemplary bone depth gauge device with the tip deployed.

[0023] Fig. 2A depicts a perspective view of a first body portion of an exemplary bone depth gauge device. Fig. 2B depicts a perspective view of a first body portion of an exemplary bone depth gauge device. Fig. 2C depicts a first body portion of an exemplary bone depth gauge device. Fig. 2D depicts a perspective view of the first and second body portions of an exemplary bone depth gauge device.

[0024] Fig. 3A depicts an exploded view of an exemplary bone depth gauge device. Fig. 3B depicts an exploded view of the body of an exemplary bone depth gauge device.

[0025] Fig. 4A depicts an exemplary deployable tip of the bone depth gauge device in the deployed configuration. Fig. 4B depicts an exemplary deployable tip of the bone depth gauge device when in the deployed and undeployed configurations. Fig. 4C depicts exemplary deployable tips that may be used with the bone depth gauge device.

[0026] Fig. 5A depicts a cross-sectional view of an exemplary bone depth gauge device. Fig. 5B depicts a perspective view of a cross-section of the proximal end of an exemplary bone depth gauge device. Fig. 5C depicts a perspective view of an exemplary bone depth gauge device.

[0027] Fig. 6A depicts a perspective view of the distal end of the bone depth gauge device, showing the first body portion having an off-centered lumen. Fig. 6B is a schematic showing a cross-sectional view of an exemplary first body portion having an off-centered lumen. Fig. 6C is a schematic showing exemplary dimensions of the first body portion and the inner lumen. Fig. 6D is a schematic showing exemplary dimensions of the first body portion and the inner lumen. Fig. 6E is a schematic showing exemplary dimensions of the first body portion and the inner lumen.

[0028] Fig. 7A depicts an exemplary metal prototype of the bone depth gauge device. Fig. 7B depicts an exemplary metal prototype of the bone depth gauge device with its components disassembled. Fig. 7C depicts an exemplary metal prototype of the bone depth gauge device with the tip undeployed. Fig. 7D depicts an exemplary metal prototype of the bone depth gauge device with the tip deployed.

[0029] Fig. 8A depicts an exemplary prototype of a bone depth gauge device. Fig. 8B depicts an exemplary industry standard depth gauge. Fig. 8C depicts rotating hidden rod with an undeployed tip as used in the exemplary prototype of the bone depth gauge device. Fig. 8D depicts rotating hidden rod with a deployed tip as used in the exemplary prototype of the bone depth gauge device. Fig. 8E depicts a cross-sectional view of the exemplary prototype of the bone depth gauge device. Fig. 8F depicts an exemplary industry standard depth gauge. Fig. 8G depicts an exemplary synthetic model of a mandible for use in test experiments. Fig. 8H depicts a table showing the “true depth” of the holes drilled into the mandible model.

[0030] Fig. 9 A depicts a plot showing the difference from “true depth” between industry standard depth gauges and the bone depth gauge device. Fig. 9B depicts a plot showing the difference from “true depth” by device and by training level of testers.

[0031] Fig. 10A depicts a plot showing results from a total accuracy analysis between an industry standard depth gauge and the bone depth gauge device. Fig. 10B depicts a plot showing the results from an accuracy analysis between devices and training level of testers.

[0032] Fig. 11 A depicts a plot showing the results from an analysis between the type of inaccurate screws selected and between devices. Fig. 1 IB depicts a plot showing the types of inaccurate screws selected with both devices and by training level.

[0033] Fig. 12A depicts a plot showing the difference from “true depth” of all holes analyzed with the industry standard depth gauge. Fig. 12B depicts a plot showing the difference from “true depth” of all holes analyzed with the prototype bone depth gauge device. Fig. 12C depicts a plot showing the difference from “true depth” of hole 1 of an industry standard depth gauge and the bone depth gauge device.

[0034] Fig. 13 A depicts a plot showing the results from an accuracy analysis. Fig. 13B depicts a plot comparing responses from survey participants when asked about the learning curves of the prototype bone depth gauge device and the industry standard depth gauge. Fig. 13C depicts a plot comparing responses from survey participants when asked about the speed of the prototype bone depth gauge device compared to the industry standard depth gauge. Fig. 13D depicts a plot showing responses from survey participants when asked about concern of the bone depth gauge device sticking in a drill hole. Fig. 13E depicts a plot showing responses from survey participants when asked about their concern of the prototype bone depth gauge device prematurely catching the bone. Fig. 13F depicts a plot showing the overall preference of testers between the industry standard depth gauge and the bone depth gauge device.

[0035] Fig. 14A depicts a plot showing the difference from “true depth” between industry standard depth gauges and the bone depth gauge device for two users that tested each device in the cadaveric model. Fig. 14B depicts a plot comparing the accuracy of the two attendings who used both the industry standard depth gauge and the bone depth gauge device in the cadaveric model.

[0036] Fig. 15 depicts a plot comparing the variability between the industry standard depth gauge and the bone depth gauge device.

[0037] DETAILED DESCRIPTION

[0038] The following discussion omits or only briefly describes conventional features of depth gauges that are apparent to those skilled in the art. Those of ordinary skill in the pertinent arts may thus recognize that other elements may be desirable and / or necessary to implement the devices, systems, and / or methods described herein. It is noted that various examples are described in detail with reference to the drawings. Reference to these various examples does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are intended to be non-limiting and merely set forth some of the many possible implementations for the appended claims. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations. As such, it is understood that this detailed description is exemplary and explanatory only and is not restrictive of the broad inventive concepts upon which the examples disclosed herein are based.

[0039] Unless otherwise specifically defined herein, all terms are to be given their broadest reasonable interpretation. This includes meanings implied from the specification as well as meanings understood by those skilled in the art and / or as defined in dictionaries, treatises, etc.

[0040] It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless otherwise specified. The term “includes” and / or “including,” when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0041] Relative terms such as “horizontal,” “vertical,” “up,” “down,” “top,” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then-described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation in actuality. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral,” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The phrases “operatively” or “operably connected” indicates such an attachment, coupling, or connection that allows the pertinent structures to operate as intended by virtue of that relationship.

[0042] Reference throughout the specification to “one example,” “an example,” or “some examples” means that a particular feature, structure, or characteristic described in connection with at least one example of the subject matter is included in at least one example of the subject matter disclosed. Thus, the appearance of the phrases “in one example,” “in an example,” or “in some examples” in various places throughout the specification is not necessarily referring to the same examples. Further, the particular features, structures, or characteristics of “one example,” “an example,” or “some examples” may be combined in any suitable manner with each other to form additional examples of such combinations. It is intended that examples of the disclosed subject matter cover modifications and variations thereof. Terms such as “first,” “second,” “third,” etc., merely identify one of a number of portions, components, steps, operations, functions, and / or points of reference as disclosed herein, and likewise to not necessarily limit examples of the present disclosure to any particular configuration or orientation.

[0043] Moreover, throughout this disclosure, various aspects can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any whole and partial increments therebetween. This applies regardless of the breadth of the range. As used herein, the term “about” in reference to a measurable value, such as an amount, a temporal duration, and the like, is meant to encompass the specified value or variations of plus or minus 20%, plus or minus 10%, plus or minus 5%, plus or minus 1%, and plus or minus 0.1% of the specified value, as such variations are appropriate and fit within the confines of a functional system.

[0044] The terms “proximal,” “distal,” “anterior,” “posterior,” “medial,” “lateral,” “superior,” and “inferior” are defined by their standard usage indicating a directional term of reference. For example, “proximal” refers to a position that is situated nearer to the center of a body or point of attachment or interest. In another example, “anterior” refers to the front of a body or structure, while “posterior” refers to the rear of a body or structure, in relation to a relative viewpoint. In another example, “medial” refers to the direction towards the midline of a body or structure, and “lateral” refers to the direction away from the midline of a body or structure. In some examples, “lateral” or “laterally” may refer to any sideways direction. In another example, “superior” refers to the top of a body or structure, while “inferior” refers to the bottom of a body or structure. It should be understood, however, that the directional term of reference may be interpreted within the context of a specific body or structure, such that a directional term referring to a location in the context of the reference body or structure may remain consistent as the orientation of the body or structure changes.

[0045] The terms “patient,” “subject,” “individual,” and the like are used interchangeably herein, and refer to any animal amenable to the systems, devices, and methods described herein. The patient, subject or individual may be a mammal, and in some instances, a human.

[0046] Described herein a bone depth gauge configured for accurate measurement of the depth of a blind hole or opening. The bone depth gauge includes a deploy able tip, forming a hook structure when deployed and configured to engage the edge of the distal opening of the hole. When undeployed, the tip fully overlaps one end of the bone depth gauge, thereby allowing the device to be easily removed from the hole. In some examples, the bone depth gauge may be used to measure the depth of a hole or opening drilled into a bone during surgical procedures and allows a surgeon or clinician to accurately determine the length of a screw required to stabilize the bone. In some examples, the bone depth gauge is configured to be easily disassembled in the event the device gets stuck in the bone.

[0047] Fig. 1 A illustrates a front view of an exemplary bone depth gauge 100 (hereinafter “gauge 100”). Gauge 100 comprises a body 102 having a distal end 104 and a proximal end 106. In some examples, the body 102 comprises a first body portion 108 coupled to a second body portion 110, wherein the average thickness or diameter of the first body portion 108 is smaller than that of the second body portion 110. In some examples, the first body portion 108 is sized to fit a hole or opening whose depth is to be measured, while the second body portion 110 is configured to remain external to the hole / opening. In some examples, the gauge 100 further comprises a deployable tip 112 connected to the distal end 104 of the first body portion 108, wherein the tip 112 when deployed forms a lip or hook configured to engage a distal end of a hole or opening (as depicted in Figs. IB and 1C). In some examples, the gauge 100 includes an outer sleeve 114 at least partially enclosing the first body portion 108 and the second body portion 110. In some examples, the gauge 100 includes a lever 116 positioned on the outer surface of the second body portion 110 and configured to be rotatable, wherein a rotation of the lever 116 actuates the deployment of the deployable tip 112. Fig. IB illustrates a perspective view of the distal end 104 of the body 106, showing the deployable tip 112 in the deployed configuration. Fig. 1C illustrates a perspective view of the gauge 100 showing the deployable tip 112 in the deployed configuration.

[0048] Referring now to Fig. 2A, shown is a perspective view of the first body portion 108 of the body 102. In some examples, the first portion 108 is a longitudinally rigid member, and may have a generally cylindrical or cuboidal shape. The first body portion 108 is sized to fit a hole or opening whose depth is to be measured and may have any suitable width or diameter. The first body portion 108 further comprises an off- centered lumen 122 extending between distal and proximal ends of the first body portion 108. Referring now to Fig. 2B, and when viewed cross-sectionally, the center of the circumference of the inner lumen 122 and the center of the circumference of the first body portion 108 are not aligned and the circumferences of each form two co-axial circles. Referring now to Fig. 2C, the first body portion 108 may further comprise a connector 124 at a proximal end having an opening 126 aligned with the off-center lumen 122, and one or more tabs 128 extending proximally from a top surface of the connector 124.

[0049] Referring now to Fig. 2D, a perspective view of the first body portion 108 and the second body portion 110 is shown. In some examples, the second portion 110 is generally hollow and comprises a circumferential wall 132 forming an inner lumen 134. In some examples, one or more slots 136 are positioned on a bottom side of circumferential wall 132. The one or more slots 136 are configured to engage with the one or more tabs 124, thereby fixedly and removably connecting the first and second body portions 108 and 110. In some examples, the first and second portions 108, 110 may be coupled via any other attachment or coupling known to one of skill in the art, including but not limited to a pin and groove mechanism, threads, external fasteners, magnets and the like. In some examples, the second body portion 110 further comprises markings 138 positioned on the outer surface of the second portion 110. In some examples, the markings 138 may be engraved, etched, scribed or glued to the outer surface of the second body portion 110. In some examples, the markings 138 have a numerical scale and indicate a measured depth. In some examples, and referring now to Fig. 3 A, the off-center lumen 122 of the first body portion 108 is aligned with the inner lumen 134 of the second body portion 110, thereby forming a single passageway extending longitudinally between distal end 102 and proximal end 104 of the body 102. In some examples, a rod 140 is disposed within the passageway, the passageway being sized to allow the rod to rotate within. In some examples, the rod 140 is a rigid elongated member. In some examples, the rod 140 may have any suitable length. For example, the rod 140 may have any length greater than the length of the first body portion 108. In some examples, the rod 140 may extend any distance into the inner lumen 134 of the second body portion 110.

[0050] In some examples, and referring now to Figs. 4A - 4C, the deployable tip 112 is connected to a distal end of the rod 140. In some examples, the deployable tip 112 is a cylindrical disc. In some examples, the deployable tip 112 has the same diameter as the first portion 108 such that when the rod 140 is positioned in the passageway of body 102, the deployable tip 112 is adjacent the distal end of the first portion 108 and fully overlaps the distal end of the first body portion 108, thereby forming a distal extension of the first body portion 108. In some examples, the deployable tip 112 may have any other suitable shape. For example, the deployable tip may be a circular disc, an ovular disc, or may have an irregular shape, such as a spiked shape, a hook shape, and the like. In some examples, the deployable tip 112 may comprise any additional features, such as a ridged or textured outer surface. Exemplary shapes of the deployable tip 112 are illustrated in Figs. 4B and 4C. In some examples, the deployable tip 112 is hidden under a lip. In some examples, the deployable tip 112 may be angled. In some examples, the deployable tip 112 is connected to the rod 140 via any suitable attachment or coupling including, but not limited to adhesives, glue, welding and the like. In some examples, the deploy able tip 112 and the rod 140 are formed as a single component part.

[0051] In some examples, the deployable tip 112 may be configured in a deployed or undeployed state. In the undeployed state, the deploy able tip 112 fully overlaps the distal end of the first body portion 108. In the deployed state, the deployable tip 112 is laterally translated from a central axis of the first body portion 108, such that the deployable tip 112 forms a lip or hook structure as illustrated in Fig 4A. In some examples, the deployable tip 112 is deployed via a rotation of the rod 140. It should be understood that due to the off-centered positioning of the rod 140 within the first body portion 108, a rotation of the rod 140 causes a lateral translation of the deployable tip 112 such that the deploy able tip 112 and the first portion 108 overlap only partially, thereby forming a lip, flange, or hook-like structure capable of engaging a distal edge of a hole or opening whose depth is to be measured. In the deployed state, the distal tip of the gauge 100 has a larger average diameter than its diameter in the undeployed state. For example, the average diameter of the distal tip of gauge 100 may increase by about 15% - 70% when the deployable tip 112 is deployed.

[0052] In some examples, and referring back to Fig. 3 A, the gauge 100 further comprises an outer sleeve 114 at least partially enclosing the body 106. In some examples, the outer sleeve 114 is substantially hollow, and may be at least partially formed in a cylindrical shape. In some examples, the outer sleeve 114 is configured to axially translate along the body 102. For example, a user may move the outer sleeve 114 along the length of the body 102 to extend or retract the first body portion 108 out of the outer sleeve 114 and expose or hide the markings on the second body portion 110.

[0053] In some examples, the outer sleeve 114 comprises a proximal edge. In some examples, the proximal edge is tapered and sits flush with the second body portion 110 such that a marking 138 corresponding to a measured depth is clearly indicated. In some examples, extending the first body portion 108 at a certain distance from the outer sleeve 114 causes the sleeve 114 to axially translate along the second body portion 110 such that the tapered proximal edge of the outer sleeve 114 clearly indicates a marking 138 corresponding to a measured depth on the second body portion 110. In some examples, the outer sleeve 114 further comprises a bone stop 154. In some examples, bone stop 154 is configured such that when first body portion 108 is inserted into a bone hole and the deployable tip 112 catches the distal edge of the hole, the outer sleeve 114 may advance towards the bone surface until the bone stop 154 contacts the bone surface, thereby indicating to a user that a measurement may be recorded. In some examples, the markings 138 on the second body portion 110 are calibrated to the length of the first body portion 108 such that each marking corresponds to a length of the first body portion 108 extending between the deployable tip 112 and the bone stop 154. In some examples, the bone stop 154 comprises an inner lumen sized to fit the first body portion 108. In some examples, the bone stop 154 may be releasably connected to the second body portion 110 via a connector 152 threadably connected to the second body portion 110. In some examples, the outer sleeve 114 and the bone stop 154 may be further secured to the body 102 via a connector 156 threadably connected to the outer sleeve 114, wherein the connector 156 comprises an inner lumen sized to fit the bone stop 154, thereby allowing the first body portion 108 to extend through the bone stop 154 and preventing the second body portion 110 to extend through the bone stop 154. It should be understood that the various component parts of the gauge 100 may be operably connected via any suitable attachment or mechanism known to one of skill in the art.

[0054] In some examples, and referring now to Fig. 5 A, the rod 140 extends proximally through the off-center lumen 122 of the first body portion 108, through the inner lumen 134 of the second body portion 110, and through an inner channel within the lever 116. In some examples, the lever 116 may comprise a shaft disposed within the inner lumen 134 of the second body portion 110 and an engageable element extending laterally outwards from the shaft. In some examples, and referring now to Fig. 5B, the rod 140 is disposed within an inner channel of the lever 116 and operably connected to the lever 116 via a pressure plate 162 and a screw 164, such that a rotation of the lever 116 causes a rotation of the rod 140. In some examples, the second body portion 110 may have a cavity or indent 166 sized to fit the engageable element of the lever 116 and allow lever 116 to rotate about an axis of rotation 168. In some examples, the lever 116 is configured to rotate through angles ranging between about 0° and 180°. In some examples, and when the lever 116 is rotated through 180°, the deployable tip 112 is fully deployed. In some examples, the lever 116 is releasably attached to the second body portion 110 via any attachment mechanism known in the art, including but not limited to screws, hinge mechanisms, glues, adhesives, and the like. In some examples, the lever 116 may be any other element operably connected to the rod 140 such that actuating the element allows the rod 140 to rotate. For example, the element may be engaged via a rotation, a sliding action, a switch mechanism, a button mechanism, and the like. In some examples, and referring now to Fig. 5C, the gauge 100 may further comprise a cap 170 configured to secure the second body portion 110 and to prevent the second body portion 110 from being proximally removed from the outer sleeve 114. In some examples, the cap 170 is configured as a screw, and may be unscrewed such that the gauge 100 may be easily disassembled in case the gauge 100 is stuck in a hole or opening while the deployable tip 112 is deployed.

[0055] In some examples, the gauge 100 may be made of any suitable rigid material, including but not limited to metals, metal alloys, titanium, aluminum, stainless steel, plastics, polylactic acid (PLA), polycarbonate, polyurethane, and the like. In some examples, the gauge 100 is made from a biocompatible material. In some examples, each component part of the gauge 100 may be made from the same material or different materials.

[0056] In some examples, and referring now to Figs. 6A and 6B, shown is a cross-sectional view of the first body portion 108 and the off-center lumen 122. In some examples, the first body portion 108 has an outer diameter 202 ranging between 1 mm and 5 mm. In some examples, the off-center lumen 122 has an outer diameter ranging between 204 ranging between 0.5 mm and 3 mm. In some examples, the minimum distance 206 between the circumference of the first body portion 108 and the circumference of the off-center lumen 122 ranges between 0.2 mm and 1 mm. In some examples, the maximum distance 208 between the circumference of the first body portion 108 and the circumference of the off-center lumen 122 ranges between 0.5 mm and 2.5 mm. In some examples, the rod 140 has an outer diameter ranging between 0.1 mm and 2.5 mm. In some examples, the average diameter increase upon deployment of the tip 112 ranges between 0.1 mm and 1.5 mm. Exemplary dimensions of the first body portion 108 and the off-center lumen 122 are depicted in Figs. 6C - 6E.

[0057] In some examples, the gauge 100 has a total length ranging between about 10 cm and 30 cm. In some examples, the first body portion 108 has a length ranging between 5 cm and 10 cm. In some examples, the second body potion 110 has a length ranging between 10 cm and 20 cm. In some examples, the width or outer diameter of the second body portion 110 ranges between 1 cm and 5 cm. In some examples, the outer diameter of the outer sleeve 114 ranges between 1.5 cm and 6 cm. In some examples, the gauge 100 is assembled from component parts. In some examples, the component parts are replaceable. In some examples, the gauge 100 is assembled from replaceable component parts. In some examples, the gauge 100 is assembled from a combination of replaceable and permanent parts. In some examples, the gauge 100 is configured to be disassembled. In some examples, the lever 116 and the rod 140 are configured to be disengaged from the body 102 for quick disassembly. For example, the gauge 100 may be disassembled while it is in use, such that the gauge 100 may be easily removed if it gets stuck in a hole or opening during a procedure.

[0058] In some examples, the gauge 100 is configured to be inserted into a hole or opening having a diameter ranging between about 0.1 mm and about 10 mm. In some examples, the gauge 100 is configured to measure a depth ranging between about 0 mm and about 100 mm. In some examples, the gauge 100 is configured to select appropriate screw sizes by accurately measuring the depth of a drilled hole in the bone. In some examples, screw lengths may range between 2 mm and 8 mm. In some examples, a plurality of deployable tips 112 and rods 140 of differing diameters may be provided and may be configured to be interchangeable. The plurality of deployable tips 112 and / or rods 140 may each have different lengths and diameters and may fit any drill hole or opening whose depth is to be measured. In some examples, the gauge 100 may comprise a drill tip such that the gauge 100 may be configured to both drill a hole and measure its depth.

[0059] In some examples, and to measure a depth of a hole in a bone using the gauge 100, the first body portion 108 is inserted into a drill hole whose depth is to be measured. The lever 116 is rotated to deploy the tip 112 of the gauge once the tip 112 extends past the distal end of the hole, and the tip 112 is used to feel for the distal edge of the hole. When the tip 112 catches the distal edge of the hole, the outer sleeve 114 is advanced distally until the bone stop 154 contacts the bone surface, such that the proximal tapered edge of the outer sleeve 114 indicates a marking 138 on the second body portion 110, the marking 138 corresponding to the depth of the hole.

[0060] Also described herein is a system for measuring the depth of a bone. In some examples, the system may comprise a gauge 100, a sensor, and a computing device communicatively connected to the sensor and a display device and comprising a processor and a non-transitory computer-readable medium with instructions stored thereon, which when executed by the processor, performs the steps comprising: receiving a depth measurement from the sensor, and displaying the depth measurement on the display device.

[0061] Also described herein is a method of measuring the depth of a bone hole, comprising providing the bone depth gauge device, inserting the first body portion into a hole until the deployable tip extends past the distal edge of the hole, deploying the deployable tip via a rotation of the lever, engaging the distal edge of the hole via the deployable tip, advancing the outer sleeve until it contacts the bone surface, and reading an indicated marking on the second body portion to obtain a depth measurement.

[0062] EXPERIMENTAL EXAMPLES

[0063] The invention is further described in detail by reference to the following experimental examples. These examples are provided for purposes of illustration only, and are not intended to be limiting unless otherwise specified. Thus, the invention should in no way be construed as being limited to the following examples, but rather, should be construed to encompass any and all variations which become evident as a result of the teaching provided herein.

[0064] Without further description, it is believed that one of ordinary skill in the art can, using the preceding description and the following illustrative examples, make and utilize the present invention and practice the claimed methods. The following working examples therefore are not to be construed as limiting in any way the remainder of the disclosure.

[0065] Example 1 : Prototyping and Portable Model Creation

[0066] A prototype depth gauge was designed with Fusion 360 CAD Software. The created .STL files were used to print parts in polylactic acid (PLA) and dark grey nylon. These various components were assembled into a functioning depth gauge (Fig. 8A). This prototype was used for validation testing by comparing it to an industry standard depth gauge (Depth Gauge 0 mm to 40 mm Scale Stainless Steel Gauge Model, DDP Instruments; Miami, FL, USA) (Fig. 8B). For the prototype, a rotating hidden rod was enclosed inside of a fixed sheath and connected to a lever that can be accessed on the main measuring body. This would allow a user to insert a straight rod into a bone drill hole, turn the lever and rotate the hidden rod, and expose a hook to catch the inner cortex (Figs. 8C and 8D). The diameter of the device would then be larger than a drill hole and prevent it from slipping out. After the device was locked in place, measurements could be determined. The fine dimensions needed for ideal function prevented from printing a closed fixed sheath. Limitations of available 3D printers included poor resolution, which prevented the creation of a complete fixed sheath around the rotating rod. The back portion was too thin, resulting in a sheath with an exposed back (Fig. 8E). This was a point of weakness, that occasionally allowed the rotating rod to pop out.

[0067] Inserted diameters were ~2.8mm for both devices, and they were calibrated to measure 0-40mm. The industry standard device used a fixed hook without a sheath (Fig. 8F). The device was constructed with an “emergency release feature,” allowing a user to disassemble it if it became stuck in the drill hole.

[0068] To allow testers to assess the depth gauge, a portable model was constructed out of a grey urethane synthetic mandible (Fig. 8G). The mandible was obtained from a urethane training skull, a proprietary Stryker training tool used to teach maxillofacial drilling and plating (Urethane Craniofacial Training Model, Stryker; Holland, MI, USA). A 3.2mm drill bit was attached to a handheld craft drill and a total of 10 holes were drilled into the right side of the mandible. Drilling was started on the buccal side of the mandible and exit holes were on the lingual side. Of the 10 holes drilled, 1 was in the ramus, 2 were in the angle, and 7 were in the body. The mandible model was made of solid urethane and lacked a synthetic marrow space. Varying mandibular contours prevented calipers from measuring the “true depth” by preventing the device’s prongs from lying flush against entrance and exit holes. To measure this “true depth”, the wooden shaft of a cotton-tipped applicator was inserted into the hole until in line with the hole’s exit. The flat shaft was visually and palpably confirmed to be flush with the exit hole and the applicator sticks were marked on the buccal side of the mandible. The marked shaft was measured with the applicator’s provided ruler to the nearest half mm. After documenting these measurements, they were compared with both the industry standard and prototype depth gauges. Both devices’ distal cortex engagement was verified through visual and tactile confirmation and yielded the same depths as the cotton applicator method. The depth of the holes ranged in size from 2.5mm to 14mm (Table 1). The left aspect of the mandible model was then clamped to a laboratory stand to mimic the position of the mandible encountered during a surgical procedure with bicortical drilling.

[0069] Table 1

[0070] Example 2: Portable Model Validation

[0071] A total of 30 individuals (12 medical students, 12 Residents, and 6 Fellows and Attendings (senior MDs)) were invited to test the prototype with the mandible model. Most residents and all fellows / attendings had experience with an industry standard depth gauge; nonetheless, all device testers were given a demonstration of how to use an industry standard gauge and the prototype depth gauge with the mandible model. They were instructed not to look for or feel for depth gauge lingual cortical engagement on the model. Testers were asked to stand while measuring, and the height of the model was adjusted per user to represent the height of the operating table. They were instructed to measure holes 1-10, randomly starting with either the industry standard or the prototype depth gauges. After completing these measurements, they would switch to the other depth gauge, and measure holes 1-10. A scribe would record the values determined. If the prototype was to become stuck, the user would indicate that the device’s “emergency release” feature was needed, and the scribe would disassemble the device to remove from the hole and reassemble it before continuing measurements.

[0072] After completing the measurements on the model, testers were asked for their feedback by completing an anonymous device quality assurance survey. The survey assessed training level, previous depth gauge usage, along with how they felt their accuracy, the learning curve, and their speed with the prototype compared to the industry standard. It also assessed whether users felt the prototype prematurely caught bone more often than the industry standard, if there was concern for the device becoming stuck in a drill hole, number of emergency releases required, and overall preference.

[0073] Example 3 : Cadaveric Model

[0074] Cadaveric mandibles have a natural marrow space dividing the buccal and lingual cortices; thus, they are ideal for testing the prototype’s function. The lower jaws of two cadavers were dissected down to the mandible. Using a 3.0 mm drill bit, bicortical drilling was performed. The final diameters were similar to the portable model. Eight holes were drilled per cadaver (16 holes total). To determine the true length, the mucosa and musculature were dissected away from the lingual side of the mandible. The shaft of a cotton-tipped applicator was then inserted and marked after confirming it was in line with each hole’s exit. The length was measured with the applicator’s provided ruler and repeated for all holes. Two attendings were invited to measure all holes with both devices. They were randomly assigned to start measurements with either the prototype or the industry standard, and the selected screws were recorded by a scribe.

[0075] Data was collected on paper and then transferred to Excel, transformed, and then analyzed with GraphPad Prism. Survey data was directly inputted into GraphPad Prism. 300 measurements per device were obtained with the synthetic mandible model. Measured depths were subtracted from the “true depth” obtained from the cotton-tipped applicators. These values were compared via a student’s paired t test, along with descriptive statistics. Descriptive statistics allowed the determination of both devices’ precision, via coefficient of variance (COV). Difference from true depth was also analyzed by level of training and device usage by a 2-Way ANOVA. Next, the percent accuracy was determined per user from their 10 measurements with each depth gauge using an ideal screw length. Ideal screws were within 1.0 mm of the true depth to prevent unnecessary protrusion while guaranteeing lingual cortex engagement (not too long or short). This 1.0 mm buffer also accounted for slight variations in drill hole length due to bone contours and placement of both device’s hooks. An inaccurate screw was defined as >1.0 mm shorter or longer than the ideal screw length, since these would not likely engage the lingual cortex or would protrude into soft tissue, respectively. A participant’s total accuracy was calculated from total ideal screws, including short and long screws using Equation 1.

[0076] Equation 1

[0077] A paired t-test was used to determine if there were any differences in accuracy between the two devices for all participants. Another 2-Way ANOVA with post-hoc Tukey’s analysis was also used to analyze accuracy measurements between the level of training and type of device being used. Inaccurate screw selections were analyzed by 2-way ANOVAs and post-hoc Turkey’s analysis to compare number of overestimated and underestimated screws by device and training level. Lastly, differences between holes were analyzed for all levels of training with each device using a 2-way ANOVA and post-hoc Tukey’s analysis. Hole 1, an angled hole, was individually analyzed with a 2 -way ANOVA testing to see which group struggled the most with its measurement. 2- way ANOVAs were also used to analyze survey data. For the cadaveric model, measurements for each tester were compared via 2-way ANOVA and accuracies were compared with a paired t test.

[0078] Example 4: Comparison between Industry Standard and Prototype Values Relative to the “True Depth”

[0079] The paired t test between industry standard and prototype depth gauge measurements were not statistically different (P = 0.1440) (Fig. 9A), however COV was found to be 1289% for the industry standard depth gauge, while the prototype’s COV was 426%. The effect of the device was not significant by device (P = 0.0959) or training level (P = 0.3059) was not significant in the 2-way ANOVA (Fig. 9B).

[0080] The accuracy for each participant was determined with the criteria described under Statistics. The total accuracy of the prototype was slightly improved (P = 0.0264), with a mean difference of 6.00% between the prototype and industry standard groups (Fig. 10A). The accuracy for medical students, residents and senior MDs with the industry standard depth gauge was found to be 80%, 93.33%, and 85.00%, respectively. The prototype accuracy was found to be 93.33%, 94.17%, and 85.00%, respectively.

[0081] When comparing the accuracy between the tester groups (Fig. 10B), significant differences were seen between levels of training (P = 0.0284), as determined by the 2- way ANOVA. Post-hoc Tukey’s analysis showed a significant decrease in accuracy between medical student testers with the industry standard depth gauge compared to residents (P = 0.0101). Medical students had a significant increase in accuracy when using the prototype compared to the industry standard depth gauge (P = 0.0020). No statistically significant difference in accuracy was seen between medical students, residents, and senior MDs with the prototype. The type of inaccurate measurements per device was classified and a significantly smaller number of underestimated screws with the prototype was observed compared to the industry standard depth gauge (P = 0.0457) (Fig. 11 A). Users with the prototype were more likely to overestimate screw size than to underestimate (P = 0.0169). The rate of overestimation and underestimation with the industry standard depth gauge was not statistically different (P = 0.3784). Further analysis by training level (Fig. 1 IB) demonstrated a significantly lower selection of underestimated screws by medical students relative to the industry standard depth gauge (P = 0.0445). Underestimations occurred less than overestimations for medical students with the prototype (P = 0.0006).

[0082] When analyzing measurements per hole, there was a large amount of variability noticed with Hole 1 with the industry standard device. This hole demonstrated underestimated values, rather than overestimated (Fig. 12A and 12B). It was the only hole with a significant angled exit and there was noticeable device slippage in the drill hole that occurred during testing. This underestimation, which was worse among medical students, improved with the prototype as demonstrated by post-hoc Tukey’s analysis (P = 0.0012) (Fig. 12C).

[0083] Medical students reported that they felt their accuracy was improved with the prototype, even though this was not significant (Fig. 13 A). For both medical students and residents, learning curve and speed appeared to be lesser and faster, respectively (Figs. 13B and 13C). Concerns about either the prototype prematurely catching or becoming stuck in a drill hole were assessed; no significant number of testers were worried about this potential issue (Figs. 13D and 13E). Even with no significant differences for these metrics, a post-hoc Tukey’s analysis of user overall preference identified a significant preference for the prototype over the industry standard model (P = 0.0251) (Fig. 13F).

[0084] In the cadaveric model, Attending 1 used the same sheath and rod used during the synthetic model testing and experienced multiple device malfunctions; this led to use of a new sheath and rod for Attending 2. Difference from the “True Depth” was modestly increased for Attending 1 with the prototype (P = 0.0479), but not for Attending 2 (P = 0.9273) (Fig. 14A). The average accuracy was not statistically different between the two devices (P = 0.3440) (Fig. 14B) but lower compared to the attending accuracy observed in the synthetic mandible model (65.65% and 81.25%).

[0085] Example 6: Synthetic Mandible Model Quantitative Data

[0086] The initial synthetic mandible model results with the 3D printed prototype exhibit no significant difference between the prototype’s and industry standard’s measurements compared to a “true depth,” demonstrating prototype non-inferiority. In addition, initial analysis shows improved precision with the prototype compared to a stainless steel industry standard depth gauge (426% vs 1289%). When examining overall accuracy based on number of ideal screws placed, some improvement was seen among users with the prototype (6.0% mean difference between groups). Further analysis of this improvement demonstrates that first time users (medical students) are able to perform at a resident and attending level by using this new mechanism, further highlighting the intuitive nature of the prototype design. The rate of underestimated screws in the synthetic mandible model was significantly lower in the prototype group. This demonstrates that guaranteed cortical catching with the depth gauge allows for the selection of fixation screws that engage both cortices and provides better fracture stabilization. More accurate Hole 1 measurements by medical students may also indicate that the device may improve angled drilling measurements. We believe that previous training with a depth gauge may have caused senior MDs to bend the prototype, similar to usage with a standard stainless-steel model, increasing the number of overestimated screws selected. Bending may also cause premature catching of the device, due to its rough 3D printed surfaces. In addition, the industry standard depth gauge appeared to warp after 30 testers, demonstrating usage of a bending technique for cortical catching. The prototype device did not require full disassembly during any testing. The “emergency release” feature was used 10 times over 300 measurements and was due to the rotating rod dislodging from the exposed hidden sheath or the sheath separating from the main body - both likely due to the limitations in resolution of 3D printing. This is not expected to occur with an unexposed hidden sheath in the stainless steel prototype in future testing.

[0087] Example 7: Cadaveric Model Quantitative Data and Study Limitations

[0088] Even with plastic and metal warping, both devices performed well in the synthetic model, with most accuracies falling within 80-100%. The improved accuracy with all depth gauges relative to Jernigan et al.’s and Liu et al.’s studies, is likely due to the usage of a urethane mandible model (Jernigan EW, et al. J Hand Surg Am. 2018;43( 12): 1138.el-l 138. e8.; Liu P, et al. Front Surg. 2021;8:774682.) The lack of extra-cortical tissue, a marrow space, and slippery fluids, likely allowed users to be more accurate with both devices, which is why the prototype was further tested in a cadaveric model with true bicortical drilling. Due to 3D printing limitations, however, the nylon / plastic prototype in a cadaver mode was compromised. Usage of the device with 30 testers before being used in the cadaver weakened the plastic of the sheath, causing the edges to peel / bow. The nature of searching for the drill hole on the lingual cortex perpetuated further warping. This in combination with the exposed section on the fixed rod allowed tissue and fixative to enter the device, allowing the rotating rod to pop out. An extruding rotating rod required the disassembly of the device multiple times to resecure the sheath and realign the rotating rod. The hidden sheath was able to separate from the main measuring body and will need to be secured with fasteners in future iterations. Switching to a new sheath and rod for Attending 2 decreased the number of malfunctions and slightly improved accuracy; however, this did not prevent fixative from entering the sheathing or the sheath being able to separate from the measuring body. Using replacement parts could also have also uncalibrated the prototype, leading to underestimated screw selections. These difficulties would not be expected to occur with a closed sheath design and metal materials, such as stainless steel (Figs. 7A - 7D). The variability of the prototype may further be improved with incorporation of laser etching, digital readings, and / or incorporation into drill bits.

[0089] The quantitative improvement in first time user accuracy, paired with initial quality assurance data elucidated the confidence instilled in younger trainees with the prototype. No medical students preferred the industry standard over the prototype depth gauge, with the majority of all groups preferring the prototype. In addition, while not statistically significant, most users felt similarly or more accurate with the prototype. This may indicate a study bias, since the goal of testing the prototype was unblinded, and contrasts with a large number of testers believing the device prematurely caught bone sooner. The bulky size of the device and specific manipulation to keep from disassembling while measuring, may be frustrating to long time users of the stainless- steel model. Medical students and residents were likely more receptive to the prototype, thus obtaining accurate readings. Reducing the bulkiness of the design and providing improved stability would hopefully alleviate these problems for long time users. The survey data also further confirmed the need for the emergency release mechanism, with 11 testers being concerned and 3 testers being uncertain about the device becoming stuck in a drill hole. By preventing the need of performing a posterior mandibular dissection to dislodge a depth gauge, the prototype is more likely to become an accepted technique for screw selection.

[0090] The 3D printed prototype depth gauge inspired confidence in trainees and improved their accuracy to the level of residents and attendings when compared with an industry standard depth gauge. Since the prototype does not require bending for accurate measurements, a lack of warping may increase the duration of usage before device retirement. The prototype includes the use of an intra-operative emergency release mechanism, a crucial development that addresses concerns of device sticking and paving the road for implementation of a depth gauge where components rotate to wider than the dimension of the drill hole to ensure catch of the inner cortex. Prototype creation with 3D printing has its limitations, such as with more complex cadaveric models. Future goals include metal prototyping. It has been demonstrated that surgeons should continue to be critical of their tools and explore updated intuitive designs that improve surgical outcomes. References

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[0125] The disclosures of each and every patent, patent application, and publication cited herein are hereby each incorporated herein by reference in their entirety. While this invention has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations of this invention may be devised by others skilled in the art without departing from the true spirit and scope of the invention. The appended claims are intended to be construed to include all such embodiments and equivalent variations.

Claims

CLAIMSWhat is claimed is:

1. A bone depth gauge device, comprising: a body having a first body portion and a second body portion and comprising a lumen extending therethrough; an outer sleeve at least partially enclosing the body and configured to axially translate along the length of the body; a rod positioned within the lumen of the body, having a deployable tip positioned adjacent a distal end of the first body portion; and a lever coupled to a proximal end of the rod and configured to actuate a rotation of the rod; wherein the deployable tip is deployed via laterally translating the deployable tip from a central axis of the first body portion via a rotation of the rod.

2. The device of claim 1, wherein the first body portion has a smaller width or diameter than the second body portion, wherein the first body portion is configured to be inserted into a hole whose depth is to be measured.

3. The device of claim 1, wherein the deployable tip when undeployed has a diameter equal to the outer diameter of the first body portion.

4. The device of claim 1, wherein the deployable tip when deployed forms a hook structure configured to engage a distal edge of a hole.

5. The device of claim 1, wherein the second body portion comprises markings indicating a depth measurement.

6. The device of claim 5, wherein the outer sleeve comprises a tapered proximal edge and a distal bone stop.

7. The device of claim 6, wherein the tapered proximal edge of the outer sleeve indicates a marking on the second body portion corresponding to a depth.

8. The device of claim 7, wherein the markings are calibrated to a length of the first body portion extending between the deployable tip and the distal bone stop of the outer sleeve.

9. The device of claim 1, wherein the device is made of a rigid and biocompatible material chosen from the group consisting of: metals, metal alloys, titanium, stainless steel, aluminum, plastics, and polymers.

10. The device of claim 1, wherein the device has a length ranging between about 10 cm to 30 cm.

11. The device of claim 1, wherein the device measures depths ranging between 0.1 mm and 100 mm.

12. The device of claim 1, wherein the lumen extending through the first body portion is positioned off-center within the first body portion.

13. The device of claim 1, wherein the first body portion has an outer diameter ranging between 1 mm and 5 mm.

14. The device of claim 12, wherein the lumen of the first body portion has an outer diameter ranging between 0.5 and 3 mm.

15. The device of claim 12, wherein the rod has an outer diameter ranging between 0.1 mm and 2.5 mm.

16. The device of claim 12, wherein the minimum distance between the outer circumference of the first body portion and the outer circumference of the lumen of the first body portion ranges between 0.2 mm and 1 mm.

17. The device of claim 12, wherein the maximum distance between the outer circumference of the first body portion and the outer circumference of the lumen of the first body portion ranges between 0.5 mm and 2.5 mm.

18. The device of claim 1, wherein the axial translation of the deployable tip causes a diameter or width increase of the distal end of the device ranging between 0.1 mm and2.5 mm.

19. The device of claim 1, wherein the device is assembled from component parts, wherein the component parts are configured to be easily disassembled.

20. The device of claim 19, wherein the device is constructed from replaceable component parts.

21. The device of claim 19, wherein the device is constructed from a combination of permanent and replaceable component parts.

22. A method of measuring the depth of a bone hole, comprising: providing the device of claim 1; inserting the first body portion into a hole until the deployable tip extends past the distal edge of the hole; deploying the deployable tip via a rotation of the lever; engaging the distal edge of the hole via the deployable tip; advancing the outer sleeve until it contacts the bone surface; and reading an indicated marking on the second body portion to obtain a depth measurement.

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