The invention relates to an instrument for determining the depth of an open or closed hole and, in particular, a depth gauge for providing a digital measurement of the depth of the open or closed hole in a bone.
Many surgical procedures require surgeons to secure a device to the bone of a patient. In some procedures, the surgeon spans and secures one or more bones, or pieces of bone, using a bone plate and screws or other fasteners. In other procedures, the surgeon uses a screw or other fastener without another device, for example, to secure a transplanted tendon. In many procedures, the surgeon drills a hole in the bone prior to securing the fastener to the bone. With a hole in place, the surgeon can more easily select a fastener of the appropriate length. Selecting a fastener of appropriate length can be very important. If the fastener is too long, the fastener may protrude from the bone. Typically, the bone abuts against soft tissues that may be harmed if the fastener is too long. Although over-drilling through a metacarpal may result only in minor damage to the fat layer within the finger, if the fastener used after drilling is too long, the patient may experience more serious complications. For example, a fastener that protrudes may be tactilely felt by the patient, prevent soft tissues (such as tendons, ligaments, or muscles) from moving over the bone surface, or even pierce the skin. As a different example, complications such as paralysis may result from a fastener mounted in the pedicle portion of the human spine that protrudes to a point where the fastener contacts the spinal cord.
During drilling, the surgeon is typically capable of feeling when the drill has penetrated through the bone from a drop in resistance of the drill against the bone. Because the simple act of drilling does not provide an exact measurement of the depth of the bone, surgeons sometimes use an analog depth gauge to measure the depth of the hole.
Analog depth gauges typically comprise a central probe member having a barb at the distal end, and a reciprocating sleeve that encircles the proximal end of the central probe member. To measure the depth of a hole in a bone, the surgeon abuts the sleeve against the proximal side of the hole, and extends the probe member into the hole. After extending the probe member beyond the distal side of the hole, the surgeon retracts the probe member, attempting to find purchase against the distal side of the hole with the barb. Typically, a marker is secured to the central probe member and the reciprocating sleeve has a graduated scale (in inches or millimeters) along a portion of its length. The surgeon reads the measurement of depth by examining the position along the graduated scale indicated by the marker secured to the central probe member.
A number of problems are associated with the analog depth gauge. Components of the analog depth gauge are typically manufactured from surgical-grade stainless steel, with the graduated scale embossed along a portion of the length of the reciprocating member, producing a highly reflective surface. Under bright operating room lights, surgeons find it difficult to see the graduated scale of millimeter-wide length increments. An accurate measurement of depth using an analog depth gauge requires the surgeon to make a close examination of the graduated scale while holding the analog depth gauge steady. If the barb loses its purchase on the distal side of the hole, either the accuracy of the measurement is decreased or the time required for surgery must be extended to permit repositioning of the barb. In surgical procedures that require many depth measurements, these difficulties are multiplied.
There are other problems associated with the analog depth gauge. An accurate reading of the graduated scale requires the eyes of the surgeon to be properly aligned with the graduated scale. Viewed from an angle, the position of the marker relative to the graduated scale may be distorted. The eyes of the surgeon may not be properly aligned with the graduated scale while the surgeon is standing erect. The surgeon may have to bend over while using the analog depth gauge to make an accurate reading because if the depth gauge is tilted in order to make the reading, the sleeve will shift relative to the probe, making the measurement less accurate and possibly causing the barb to lose its purchase on the distal side of the hole, resulting in the same disadvantages mentioned above.
Accordingly, there has been a need for an improved depth gauge for surgical procedures.
The present invention provides a system for faster and more accurate measurements of depth during surgery and permits an adjustment of the orientation screen to permit easy viewing of a display that provides depth measurement information.
Accordingly, in an embodiment of the invention, a generally elongated instrument is provided for measuring the depth of a hole with a first edge and a second edge, the instrument having a longitudinal axis, the instrument comprising: a first generally elongated member substantially oriented along the longitudinal axis and which is insertable in the hole, the first member comprising a portion positionable against a first surface in which the first edge of the hole is formed; a second generally elongated member substantially oriented along the longitudinal axis and which is slidably connected to the first member, the second member comprising a portion positionable against a second surface in which the second edge of the hole is formed and a sensor that generates an electronic signal that varies in relation to the distance between the first member and the second member; and a rotatable electronic display for displaying information representative of the distance measured by the sensor.
In another embodiment, a depth measurement gage is provided for measuring a hole depth, comprising: a measurement tool that converts an extension length of a measuring element into a representative electronic signal; a display assembly connected to the depth measurement gage, the display assembly comprising: a rotatable display that comprises: a display screen for displaying a numeric representation corresponding to the extension length based on the electronic signal received from the measuring tool; display electronics that receive the electronic signal, converts it into a displayable value, and drives the display to display the value; and a locking mechanism that holds the display at a particular orientation; wherein the rotatable display is rotatable about an axis normal to a surface of the display screen; the display assembly further comprising: a housing that connects with and supports the rotatable display; the depth measurement gage further comprising: a rotation element that allows the rotatable display to rotate about an axis parallel to a surface of the display screen.
In another embodiment, a depth measurement gage is provided for measuring a hole depth, comprising: a measurement tool that converts an extension length of a measuring element into a representative electronic signal; an elongated housing extending along a longitudinal axis of the measurement tool; a rotatable rectangular display that, when in an initial position, has a side that is parallel to the longitudinal axis, the display comprising: a display screen for displaying a numeric representation corresponding to the extension length based on the electronic signal received from the measuring tool; display electronics that receive the electronic signal, converts it into a displayable value, and drives the display to display the value; and a locking mechanism that holds the display at a particular orientation; wherein the rotatable display is rotatable about an axis normal to a surface of the display screen.
In another embodiment, a depth measurement gage is provided for measuring a depth of a hole, comprising: a measurement tool that converts an extension length of a measuring element into a representative electronic signal that is wirelessly transmitted; a display assembly connected to the depth measurement gage, the display assembly comprising: a wireless rotatable display that comprises: a display screen for displaying a numeric representation corresponding to the extension length based on the electronic signal received from the measuring tool; a wireless antenna and signal receiver that receives the wirelessly transmitted electronic signal; and display electronics that receive the electronic signal, converts it into a displayable value, and drives the display to display the value; the display assembly further comprising: a housing that connects with and supports the rotatable display.
The foregoing and other objects, advantages, and features of the present invention will be apparent from the following detailed description and the accompanying drawings illustrating various embodiments of the invention, in which:
FIG. 2A′ is an enlarged pictorial detail view of a circled portion of the cross-section shown in
FIG. 2B′ is an enlarged pictorial detail view of a circled portion of the cross-section shown in
After drilling a hole in a bone during surgery, a surgeon will often use an instrument to measure the depth of the hole before selecting a fastener. The system and method of the present invention are performed using a surgical depth gauge with an electronic sensor and digital display, which provide an easier, faster, and more accurate means for measuring depth during surgery. While a variety of embodiments of the invention are shown in the attached figures, those skilled in the art will recognize that there are other mechanical and electrical arrangements for accomplishing surgical depth measurements digitally in accordance with the present invention. Various alternative embodiments, features and variations are therefore also described herein.
Instruments used for surgical procedures must be robust both to the solid and liquid contaminants encountered during surgery (such as tissue and blood) and the temperatures, pressures, and fluids encountered during sterilization (such as hydrogen peroxide gas). The two embodiments of the present invention shown in the attached drawings illustrate two alternative form factors for the sterilization-proof and contamination-proof surgical depth gauge in accordance with the present invention. In a first embodiment 100 shown in
With a hole already drilled, a surgeon might reach for a surgical depth instrument of the present invention as shown by the instrument 100 of
An alternative embodiment of the form factor for the present invention is shown in
Turning back to the first embodiment of the form factor shown by instrument 100 in
An embodiment of the method for taking depth measurements in accordance with the present invention begins with the surgeon holding the instrument 100 in either a right or a left hand.
In an embodiment, the method of the present invention also comprises a step wherein the surgeon extends the probe 160 into the hole 20 of the bone portion 10.
As shown in FIGS. 2A′ and 2B′, the bone portion 10 is bicortical, i.e., the bone portion 10 has a first, proximal cortical layer 12 (see FIG. 2A′), a cancellous layer 14, and a second, distal cortical layer 16 (see FIG. 2B′). It should be noted, however, that the present invention is suitable for use with bones having other structures, including solid cortical, unicortical, or cancellous bones. The present invention may even be used for surgical depth measurement of holes or cavities in other types of tissue.
As described above, the hole 20 may be a hole formed in the bone portion 10. In using the instrument 100 to measure the distance from a proximal surface 30 formed on the proximal cortical layer 12 to a distal surface 40 formed on the distal cortical layer 16, the instrument 100 operates so that the distance between the distal end 122 of the tissue guard 120 (which abuts the proximal surface 12) and the proximal end of the indented hook 165 (which has purchase on the distal surface 16) is determined by an electronic sensor, generating a precise measurement of the distance between the proximal surface 30 and distal surface 40. The electronic sensor may comprise inductive or capacitive elements in a read assembly on a printed circuit board and inductive or capacitive elements in an increment assembly on a printed circuit board within the compartment 146 of the body 140 (see
The distal end of the probe 160 is equipped with an indented hook 165 in the instrument 100 shown in
With the indented hook 165 at its distal end, the probe 160 can take purchase on the distal surface 40 of the bone portion 10. The instrument 100 is shown in this position in FIGS. 2B and 2B′. Once the indented hook 165 has completely passed through the distal edge 26, the shaft of the probe 160 is shifted slightly, laterally so that the indentation in the indented hook 165 abuts against the distal edge 26. A slight retraction of the probe 160 then permits the indented hook 165 to engage (or take purchase on) the distal surface 40 of the distal cortical layer 16. Retraction of the indented hook 165 is accomplished in accordance with the instrument 100 by squeezing the side grooves 180 with thumb and forefinger, and pulling lightly. In this manner, the proximal surface of the indented hook 165 and the distal end of the tissue guard 120, respectively, are positioned against the distal surface 40 and proximal surface 30 of the bone portion 10 and, through the use of slight tension, are retained thereon. In reading the electronic display when the invention is maintained in this physical configuration, the surgeon is provided with an accurate measurement of the depth of the hole 20 in the bone portion 10.
Although in the embodiment depicted in
The instrument 100 further includes a reference portion that abuts the proximal surface 30. In the embodiment of the invention shown in the attached drawings, the reference portion is provided by a tissue guard 120. The tissue guard 120, as shown by way of example in
In an embodiment, the end of the body 140 nearest the tissue guard 120 has a threaded nipple (not shown in
The tissue guard 120 and probe 160 are concentrically arranged such that the distal end of the tissue guard 122 abuts the proximal surface 30 of the bone portion 10 in a manner similar to that of a bone plate or fastener head. Accordingly, the tissue guard 120 and indented hook 165 cooperate such that their relative position (and, therefore, distance) provides an accurate measurement of the depth of the hole 20 such that a screw or fastener may be selected whose length is accommodated by the hole 20.
In the embodiment of the invention provided by the instrument 100, movement of the sealed housing 130 is effective to shift the position of the probe 160 because the probe 160 and sealed housing 130 are attached as shown in
In the embodiment of the sealed housing 130 shown in
When sealed, the embodiment of the sealed housing 130 shown in
Although the instrument 100 shown in the attached drawings includes a display, it will be understood by those of skill in the electronic arts that the present invention may be practiced using an external display in communication with a wireless device. In the instrument 100, a wireless transmitter may be connected to the read-head assembly within the sealed housing 130. In such wireless embodiments, a wireless receiver would be positioned a short distance away from the surgical depth gauge (for example, on a platform near the operating table), and an electronic display would be connected to the wireless receiver. In addition, as a supplement to a visual display, the instrument may be provided with an audio readout capability that may, for example, beep or provide another audible signal when the instrument senses that movement of the probe has stopped, and there has been an appropriate interval in which to take a measurement. In addition, the instrument may include the capability for the distance displayed to also be audibly conveyed through a simulated voice from a speaker maintained within the instrument. In this manner, the surgeon's determination of the distance may also be verified from the audible articulation of the distance, providing further confidence in the accuracy of the reading.
A perspective view of the instrument 100 from the bottom is shown in
Some structural features of the invention shown in
When slidably connected as shown in the instrument 100, the present invention does not require oil lubricants, such that the materials are entirely compatible with a surgical environment. Referring to
The electronic sensors used in the system and method of the present invention comprise capacitive and inductive sensors and sensor assemblies. Sensors and sensor assemblies are readily available commercially from manufacturers such as Sylvac and Mitutoyo. For example, capacitive and inductive read-head and write-head assemblies are used in digital calipers, such as that made by Mitutoyo America Corporation, 965 Corporate Blvd., Aurora, Ill., and by Guilin Measuring and Cutting Works, 106 Chongxin Road, Guangxi, Guilin 541002, Peoples Republic of China. In general, the electronic sensor secured within the compartment 134 of the sealed housing 130 takes the form of a conventional electronic sensor, display, and power source assembly for use in a length measuring device relying on inductive or capacitive or other elements. For some embodiments, inductive elements may provide advantages to the extent that inductors provide more uniform and consistent measurements through a wider variety of environmental conditions. For example, the instrument 100 may be built with a pattern of inductive loops laid down along the sensor pattern compartment 146 of the body 140, and a facing read-head assembly secured within the compartment 134 of the sealed housing 130.
In various embodiments of the present invention, the electronic sensor may be connected with a microprocessor or other digital electronic device in order to produce an output for an electronic display, such as a liquid crystal display or light-emitting diode display. In other embodiments, the microprocessor or other digital electronic device may be connected to a wireless transmitter, as described above. In some embodiments, a signal conditioning circuit may interpose the inductive or capacitive elements of the electronic sensor and the microprocessor or other digital electronic device used to drive the display, thus ensuring that correct input current and voltage levels are provided to the various components. As will be recognized by skilled artisans, a power source, such as a primary or secondary battery, may be connected to the signal conditioning circuit or to the microprocessor directly.
The microprocessor or other digital electronic device used to drive the display may be configured to provide depth measurements in inches, millimeters, or fractions thereof. In various embodiments, the sealed housing 130 may include buttons that permit the surgeon to select how the preferred unit of measurement is displayed. In an embodiment, the microprocessor or other digital electronic device is configured to provide a positive reading for depth as the probe 160 is extended from the proximal surface 30 toward the distal surface 40 of the bone portion 10, and a zero reading when the probe 160 is retracted so that the catch of the hook is flush with the distal end of the tissue guard. In another embodiment, the present invention may be configured to permit a re-zeroing of the device by providing a calibration button. In still other embodiments, the present invention may provide on and off buttons (or an on/off toggling button), or a button for storing and holding the measurement presently shown on the display for reading after the probe 160 has been moved. In such embodiments, the buttons may be formed in the sealed housing 130.
The electronic display of the present invention is selected for quick and easy visual inspection during surgery. The electronic display, however, may provide information in addition to depth measurements. For instance, the present invention may be provided as part of a kit (not shown) including a bone plate that mates with a head and shank formed on a screw. The electronic sensor may be calibrated to compensate for or provide an offset corresponding to a portion of the screw head and shank received within the bone plate. Accordingly, the present invention could be configured to suggest a particular screw selected from the kit for use with the bone plate, rather than a measurement of length. The electronic display may also provide an indication that the reading is not stable, for example, because the tissue guard 120 and probe 160 are not generally stationary relative to one another. This event is more typical when compressible soft tissue is caught on the indented hook 165, or between the tissue guard 120 and the proximal surface 30, or in general when the distal end of the probe 160 is not securely positioned. In this respect, it should be noted that the probe 160 may be provided without any mechanical securement at its distal end. As an example, the distal end of the probe 160 may be inserted to a depth such that its distal end is coincident with, but generally does not extend beyond, the distal edge 26 of the hole 20. In using such an embodiment, the surgeon may place a stop or finger on the distal surface 40 of the bone portion 10 to stop the probe 160 when it has reached the distal edge 26.
In an embodiment, the electronic sensor and accompanying electronics can be shielded from electromagnetic interference, for example, by coating the inside of the sealed housing 130 with a conductive paint containing metal microspheres. Such shielding may be effective in reducing interference from low frequency magnetic fields, or other stray electromagnetic fields. Shielding is desirable at least because the method of the present invention may be practiced in conjunction with the use of a magnetic pad for holding surgical instruments (not shown in
Although the displays shown in
Therefore, referring to
Referring to
The display 340 is preferably a generally circular shape and comprises a display screen 350 along with display electronics 352 that are used to operate the display screen 350. The display screen 350 is preferably a liquid crystal display (LCD), since this is a relatively low-power type of display well suited for a measuring instrument. This LCD display could provide some form of back-lighting that is known in the art. The display screen 350 could also be implemented as a light-emitting diode (LED) display. This display, while consuming greater power than the LCD display, could serve to improve readability. Also, other display technologies, such as organic light-emitting diodes (OLED) and the like could be utilized. The display could be arranged in a number of ways, ranging from a simple seven-segment numeric display to a screen display comprising a color pixel grid. The display screen 350 and display electronics 352 are affixed within a circular housing comprising an upper 342 and a lower 360 housing component.
In order to permit a locking and holding of the display 340 at a particular orientation, one or both of the following may be provided: a plurality of locking holes 346 on a side edge of the upper display housing 342, and a plurality of locking grooves 348 also located on a side edge of the upper 342 and lower 360 housing components. It should be noted that the location of the locking holes 346 and/or locking grooves 348 could be provided on the lower housing 360, or even on an upper or lower surface of the housing components 342, 360. The operative action of the locking holes 346 and locking grooves 348 will be described in more detail below along with the other elements with which they interact.
The upper housing component 342 may provide a window 344 through which the display screen 350 can be read. It is also possible that the upper housing component 342 would have a clear surface through which the display screen 350 could also be read.
Referring to
When the display 340 is a wireless display, then no such access slots 362 need to be provided. Such a display 340 may be easily placed into the display assembly 300 and become operative with little effort. For the wireless display 340, the display electronics 352 comprises an antenna and receiver that can read signals provided by the measuring device itself. Any form of short range wireless communication hardware and protocol may be utilized here.
In the embodiment shown in
The display 340 rests between a proximal (to the measuring device) support 386 and a distal support 374. The proximal support 386 has a curved raised edge designed to match a curvature of the display 340. Protrusions 390 are provided on a raised edge of the proximal support 386 that serve to engage the locking groove 348 of the display 340 when at least some minimal force provided by a spring 336 and locking slider 332 (see also
The distal support 374 comprises a spring slot 378 into which the spring 336 rests. It also comprises a slider recess 376 into which the locking slider 332 rests, as well as a corresponding pin slot 380 in which the slider pin 334 rests. The locking slider 332 preferably has a spring hole 338 into which a portion of the spring extends. The spring hole 338 helps to maintain the spring in position, although this is not essential, and other mechanisms, such as an additional pin, may be used. The slider pin 334 itself is designed to engage one of the locking holes 346 of the display. The spring 336 resting in the slot is in a generally compressed state, such that it provides a force that biases the locking slider 332 and its slider pin 334 into the display 340.
Thus, a user wishing to orient the display, moves the locking slider 332 towards the distal (away from the measuring device) end of the display assembly 300 and against the spring 336 bias. This causes the slider pin 334 to disengage from the locking hole 346 so that the display 340 can be rotated about is axis about the pin 364. Absent a biasing force, the display 340 is also slightly moved in a distal lateral direction such that the protrusion(s) 390 disengage the locking groove(s) 348. The lower housing 370 also comprises a handle portion 372 that, when combined with a handle portion 312 of the upper hosing 310, provides an easy-to-grasp element for the user.
The upper housing 310 may be designed as a three-piece unit or as a one-piece unit. The three-piece configuration comprises a separate proximal support member 320, distal support member 314, and transparent cover 324. In the one-piece unit, these the proximal support member 320, distal support member 314, and transparent cover 324 may be provided as a single unit, either via assembly or construction as a monolithic unit.
The transparent cover 324 (see also
The distal support 314 comprises a slot 316 into which a top portion of the locking slider 332 protrudes. A lever 331 may be affixed to a top surface of the locking slider 332 and serves to form a relatively secure seal of the slider slot 316 such that contaminants cannot readily enter the slider slot 316. Thus, when the user wishes to reorient the display 340, the user moves the lever 331 towards the distal end of the display assembly 300 and against the spring 336 bias to disengage the display 340 from the locking mechanisms (332, 390). Once the display 340 is disengaged, it may be rotated into a locking position (one in which the slider pin 334 aligns with the locking hole 346 and the locking groove 348 aligns with the protrusion 390). The user releases the lever 331 and the spring 336 biases the locking slider 332 to move the slider pin 334 into the locking hole 346 and biases the display 340 against the curved side surface 388 of the proximal support 386, thereby engaging the locking groove(s) 348 with the protrusion(s) 390.
Referring to
It should be noted that the embodiment shown provides for a rectangular cross section of the support elements of the display assembly 300 and the pivot arm 391. However any practical cross-sectional shape can be implemented, such as round, oval, polygonal or other closed curved shape. Furthermore, an additional pivot arm similar to the pivot arm 391 described above could be provided at the end of the pivot arm 391 in order to permit rotation of the display in three full dimensions.
Furthermore, the rotating mechanisms described above relating to a pin and hole or slot to permit rotation could also be implemented using supporting roller, spherical, or other forms of bearings, or could also be implemented with a ball socket type arrangement. In the latter arrangement, the locking mechanism could simply be a frictional fit that may or may not be adjustable in the frictional forces created. When a pivoting mechanism is used, the pivot may be placed central to the display, or offset. Furthermore, the display 340 itself can be located at either a proximal or distil end of the display assembly 300 instead of in a central region.
In an embodiment, the display screen 350 is provided directly on the rotatable body section 311. In this embodiment, a series of grooves and protrusions or bumps and holes may be provided on an inner surface of the body 140 and outer surface of the rotatable body section 311 in order to provide discrete orientation positions for this section. Alternately, the rotatable body section 311 can be designed to operate with a frictional fit so that it can be rotated when a certain force is deliberately applied but is unlikely to rotate during normal measurement use.
In a further embodiment, as illustrated in
Two final embodiments are illustrated in
In all of these designs, it is possible to include an option in which the image on display itself can rotate as well, although this would be practical when the display comprises an array of pixels.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
A variety of embodiments of the invention are described and illustrated herein; variations of those embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. It is not the intent of the inventors to surrender or otherwise dedicate any valid claim to the subject matter described herein to the public, and the following claims are intended to capture the entire scope of the invention herein described.
This application is a continuation of co-pending U.S. patent application Ser. No. 12/391,814, filed Feb. 24, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 11/376,399, filed Mar. 15, 2006, now issued as U.S. Pat. No. 7,493,703, which is a continuation-in-part of U.S. patent application Ser. No. 11/081,147, filed on Mar. 16, 2005, now issued as U.S. Pat. No. 7,165,336, the entire content of these being herein incorporated by reference.
Number | Date | Country | |
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Parent | 12391814 | Feb 2009 | US |
Child | 12572733 | US |
Number | Date | Country | |
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Parent | 11376399 | Mar 2006 | US |
Child | 12391814 | US | |
Parent | 11081147 | Mar 2005 | US |
Child | 11376399 | US |