Field of the Invention. The invention relates generally to rotary drilling tools for forming an osteotomy or hole in bone or other cellular material to receive an implant or other fixation device, and more specifically toward a novel stop gauge that prevents penetration of the drilling tool beyond a predetermined depth, as well as to a novel guided surgery jig used in combinations therewith.
Description of Related Art. An implant is a medical device manufactured to replace a missing biological structure, to support a damaged biological structure, or to enhance an existing biological structure. Bone implants may be found throughout the human skeletal system, including dental implants in a jaw bone to replace a lost or damaged tooth, vertebral implants used to secure cages, joint implants to replace a damaged joints such as hips and knees, and reinforcement implants installed to repair fractures and remediate other deficiencies, to name but a few. The placement of an implant often requires a preparation into the bone using either hand osteotomes or precision drills with highly regulated speed to prevent burning or pressure necrosis of the bone. After a variable amount of time to allow the bone to grow on to the surface of the implant (or in some cases to a fixture portion of an implant), sufficient healing will enable a patient to start rehabilitation therapy or return to normal use or perhaps the placement of a restoration or other attachment feature.
In the example of a dental implant, preparation of a hole or osteotomy is required to receive a bone implant. The depth of an osteotomy is determined by the amount of axial movement that the clinician imparts on a drilling tool as he or she inserts the drilling tool into the bone tissue. If the depth of the bore is too long, it can puncture the sinus cavity in the maxillary, or the mandibular canal (which contains nerves) in the mandible. Likewise, the roots of adjacent teeth also can be adversely affected by an improperly sized osteotomy.
To ensure that a drilling tool is inserted into the bone to a known depth, the drilling tool may contain markings that signify specific depths. For example, a drilling tool may have bands of etched markings that indicate the bore depth at several locations. The use of these visual markers is, of course, limited to the clinician's ability to see the mark as the drilling tool is being inserted into the patient's mouth. Accordingly, the clinician is required to keep his or her visual attention on the depth marker as he or she slowly proceeds with the axial movement that causes the drilling tool to be inserted deeper and deeper into the bone. Visibility in such cases can be obscured by irrigation fluid and tools and other obstructions, making the traditional visual markers sometimes difficult to use.
The prior art discloses various types of stop elements that prohibit insertion of a drill or bur into the bone tissue beyond a predetermined depth. The methods employed by these prior are schemes are either difficult/cumbersome to use, or are expensive to produce. A few notable examples are described below.
U.S. Publication No. 2007/0099150 to Daniele discloses a depth stop collar for a dental drill. The shank of the drill has a series of grooves. Pawls at the top of the stop collar selectively engage the grooves in the shank to set the drilling depth. Drilling depth is adjusted by moving the stop collar up or down along the drill shank.
German patent document DE3800482 to List teaches a depth stop for a surgical drill. A series of annular ribs are formed along the drill shank. A stop collar fitted with a spring and ball locking mechanism sequentially snaps into the annular ribs to set the drilling depth.
U.S. Pat. No. 7,569,058 to Ralph discloses an adjustable depth stop for a surgical device used to form pre-threaded holes in bone. A series of annular ribs are formed along the length of the tap shank. A stop collar fitted with flexible pawls sequentially snaps into the annular ribs to set the tap depth. A screw-on locking cap threads over the flexible pawls to secure them in an adjusted position.
Common disadvantages perceived among the prior art are many, and include lack of ability to be installed on and removed from any drilling tool. Rather, in each case a specially manufactured drilling tool is required. Another common disadvantage is that multiple grooves must be formed in the tool shank. For high-speed applications, the multiple grooves risk weakening the shank with multiple stress-concentrating nodes that invite unwanted vibrations in use. The multiple grooves also add to manufacturing expense. And furthermore, each groove in the shank represents a hard-to-clean location for post-operative sterilization prior to re-use. Multiple grooves in the tool shank compound this concern, resulting in increased time and effort required during the customary sterilization and cleaning processes. Still further disadvantages of the prior art depth-stop concepts relate to the overall lack of suitability for retrofit use across a wide range of drilling tools marketed by different manufacturers. And yet further, none of the prior art depth-stop concepts are well-suited for use with the growing demand for guided surgery applications.
Korean patent document KR20060096849 to Hsieh discloses a guided surgery system in which a mouth jig has a guide feature to provide location and orientation control. Hsieh teaches the diameter of the guide feature can be reduced by adhering an additional magnetic guide bushing. However, the Hsieh system is not coordinated for use with a depth-stop feature, thereby making it difficult or cumbersome to utilize depth control in combination with guided surgery.
There is therefore a need in the art for an improved stop element that prohibits insertion of a surgical drilling tool or bur into the bone tissue beyond a predetermined depth, and which can be used conveniently in combination with a jig for guided surgery.
According to a first aspect of the present invention, an adjustable stop gauge is provided for a bone drilling tool of the type having a body section and a shank joined in end-to-end fashion. The adjustable stop gauge comprises a tubular collar adapted to partially surround the body of a bone drilling tool. The collar defines a stop ring that is adapted to limit over-penetration of an apical tip of the drilling tool into bone. An indexing adapter is connectable to the drilling tool and moveably supports the collar. The indexing adapter is configured to selectively locate the stop ring in any one of a plurality of longitudinal stations, wherein each station represents a different penetration depth of the drilling tool in the bone.
The indexing adapter can be easily installed on and removed from any drilling tool. The indexing adapter enables an adjustable position collar without the prior art requirement of forming multiple grooves in the shank of the drilling tool, thereby maintaining the strength of the drilling tool and reducing the tendency for unwanted vibrations in use. Furthermore, the indexing adapter reduces the need for expensive additional manufacturing operations on the drilling tool in order to accommodate an adjustable collar. And still further, the indexing adapter decreases the effort required post-operatively during the customary sterilization and cleaning processes, as compared with prior art style adjustable position depth stop systems.
According to a second aspect of the present invention, a stop gauge is provided for a bone drilling tool of the type having a body section and a shank joined in end-to-end fashion. The stop gauge comprises a tubular collar that is centered about a central axis. The collar is adapted to surround, at least partially, the working end or body of a drilling tool. The collar has a stop ring that is adapted to limit over-penetration of an apical tip of the drilling tool into the bone. The collar includes a plurality of vane slots that are configured to permit the pass-through of irrigating fluid.
The vane slots permit irrigating fluid to better wash over the osteotomy site, thereby allowing for better heat management at the treatment site. When an optional auto-grafting rotary osteotome is used as the hole-forming tool, the generous flow of irrigating fluid through the vane slots allows the osteotome to generate hydrodynamic effects which substantially enhance the hole formation procedure.
According to a third aspect of the present invention, a dental tool assembly is provided for forming a hole of predetermined depth in bone. The assembly comprises a tubular collar adapted to partially surround the body of a bone drilling tool. The collar defines a stop ring that is adapted to limit over-penetration of an apical tip of the drilling tool into bone. A jig is configured to be secured relative to a target drilling location. The jig has a guide bushing that provides a laterally open alignment valley adapted to receive the collar of the stop gauge. The alignment valley includes an internal abutment step which is adapted to engage the stop ring of the collar when the apical tip of a drilling tool has reached a predetermined penetration limit in the bone.
The alignment valley provides maximum access and visibility into an edentulous jaw site for the surgeon. The laterally open configuration allows substantially increased irrigation capacity to the osteotomy, as compared with prior art designs. The open configuration of the alignment valley allows the bone to freely expand laterally, such as when used in combination with a rotary expanding osteotome. Relatively long-length drilling tools can be navigated laterally into position. The abutment step establishes a stable, elevated surface configured to engage the spinning stop ring of the collar when the drilling tool has reached the desired drilling depth. Unlike the often imperfect surface of a patient's natural skin or exposed bone, the abutment step can afford the surgeon certain and immediate haptic feedback when the desired drilling depth has been achieved. In cases where the collar is made from a polymeric material, the abutment step may help avoid abrasion or distortion, thus extending the operating life of the collar and perhaps enabling re-use of the collar in one or more future surgical applications.
These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein:
Referring to the figures, wherein like numerals indicate like or corresponding parts throughout the several views,
The rotary osteotome 36 is described in U.S. Pat. No. 9,326,778 issued May 3, 2016, and also in WO 2015/138842 published Sep. 17, 2015, both to Huwais, the entire disclosures of which are hereby incorporated by reference in jurisdictions that recognize incorporation by reference. Generally stated, the auto-grafting osteotome 36 includes a shank 40 and a working end or body 42. The shank 40 is basically an elongated cylindrical shaft that establishes a longitudinal axis of rotation A for the rotary osteotome 36 when driven at high speed (e.g., greater than 200 rpm; typically in the range of 800-1500 rpm) by the drill motor 38. A drill motor engaging interface 44 is formed at the distal upper end of the shank 40 for connection to the drill motor 38. Of course, the particular configuration of the interface 44 may vary depending on the type of drill motor 38 used, and in some cases may even be merely a smooth portion of the shank shaft against which the jaws of a collet grip by friction alone. An annular groove 45 is disposed at a predetermined intermediate axial location along the shank 40. The groove 45 is preferably shallow, with relatively square inset corners. The longitudinal length (i.e., width) of the groove 45 may be in the range of about 10% to 100% of the diameter of the shank 40, although widths of greater or lesser dimensions are possible.
The body 42 of the osteotome 36 joins to the shank 40 at a transition 46, which may be formed with a tapered or domed shape. The angle or pitch of the transition 46 may be described by a transition angle measured relative to the longitudinal axis A. The transition 46 normally helps spread the irrigating fluid something like an umbrella as the surgeon irrigates with water (or saline, etc.) during use. Irrigation of the osteotomy site 32, as depicted at 39 in
The working end or body 42 of the osteotome 36 has conically tapered profile decreasing from a maximum diameter adjacent the shank 40 to a minimum diameter adjacent an apical end 48. The apical end 48 is thus remote from the shank 40, with the aforementioned groove 45 being located along the shank 40 at a predetermined distance from the apical tip 48 for reasons that will be described. The working length or effective length of the body 42 is proportionally related to its taper angle and to the size and number of osteotomes in a surgical kit in cases where the osteotomy 32 is formed by a sequence of progressively larger osteotomes 36. Preferably, all osteotomes 36 in a kit will have the same taper angle, and the diameter at the upper end of the body 42 for one osteotome is approximately equal to the diameter adjacent the apical end of the body 42 for the next larger size osteotome.
The apical end 48 may include one or more lips 50. A plurality of grooves or flutes 52 are disposed about the body 42. The flutes 52 are preferably, but not necessarily, equally circumferentially arranged about the body 42. A rib or land is formed between adjacent flutes 52, in alternating fashion. Thus, a four-flute 52 osteotome 36 will have four interposed lands, a ten-flute 52 osteotome 36 will have ten interleaved lands, and so forth. Each land forms a working edge. Depending on the rotational direction of the osteotome 36, the working edge either functions to cut bone or condense bone. That is, when the osteotome 36 is rotated in the cutting direction, the working edges slice and excavate bone (or other host material). However, when the osteotome 36 is rotated in the condensing (non-cutting) direction and pushed into the osteotomy 32 with modulating pressure, the working edges compress and radially displace bone with little to no cutting whatsoever. This compression and radial displacement is exhibited as gentle pushing of the osseous structure laterally outwardly in a condensation mechanism.
To ensure that the apical end 48 of the rotary osteotome 36 (or the tip of a traditional drilling bur or other boring tool) does not exceed a desired depth in the bone, an axial stop gauge, generally indicated at 54, is provided. The stop gauge 54 is shown exploded in
The collar 56 may, optionally, include a plurality of vane slots 60 configured to permit irrigating fluid 39 to readily pass-through to reach the body section 42 of the osteotome 36. The vane slots 60, therefore, allow the irrigating fluid 39 to better wash over the osteotomy site 32, thereby allowing for better heat management at the treatment site. As illustrated by the broken directional arrows in
The vane slots 60 may, optionally, be configured as an integral impeller to accelerate the radially inward flow of water. In this configuration, the rotating motion of the collar 56 (synchronously locked to the rotating osteotome 36 through friction) is used as an energy source, together with the shape or configuration of the vane slots 60, to facilitate movement of the irrigating fluid inwardly toward the osteotome 36. Each pair of adjacent the vane slots 60 may be seen as being circumferentially separated by a respective longitudinally extending blade 62. The blades 62 terminate at the lower end of the collar 56, i.e., near the stop ring 58, at an annular lower cuff 64. Said another way, the lower cuff 64 is the region of the collar 56 between the stop ring 58 and the vane slots 60. Similarly, an annular upper cuff 66 is formed by the region of the collar 56 between its upper end and the vane slots 60. The blades 62 thus extend between the upper 66 and lower 64 cuffs forming a ventilated cage-like structure.
In the illustrated embodiment, the vane slots 60 are spaced from one another in equal circumferential increments about the collar 56, and the blades 62 are each of generally equal width forming a symmetrical appearance. The vane slots 60 and the interposed blades 62 respectively extend in generally straight axial paths parallel to one another and parallel to the central axis B. However, in a contemplated alternative embodiment, the vane slots 60 and blades 62 may be spiraled or slanted in their arrangement around the collar 56 to promote irrigation flow 39 if desired. Indeed, the vane slots 60 need not even be slots per se, but could in fact be designed as holes of round or other geometric shape that permit the pass-through of irrigating fluid (with or without an impeller effect). The number and/or relative sizes of the vane slots 60 may depend on the exterior diameter of the collar 56 and the width of the intervening blades 62. In the examples shown in
Turning to
The stop gauge 54 may be of a fixed length design, i.e., so that only one predetermined drilling depth is possible, or alternatively may include an indexing adapter, generally indicated at 70, that allows the collar 56 to be moved to various pre-selected longitudinal stations relative to the osteotome 36. In this manner, the stop ring 58 can be set or re-set, at the time of use, at different heights relative to the apical end 48 of the osteotome 36, thus achieving different pre-determined drilling depths into the bone. For example, in the illustrated embodiment five longitudinal stations are established, respectively corresponding to drilling depth limits of 6, 8, 10, 11.5 and 13 mm. That is to say, when the collar 56 is moved to the first longitudinal station along the indexing adapter 70, the axial distance between the apical end 48 and the stop ring 58 is 6 mm. In
As shown in the cross-sectional view of
The top end of the indexing adapter 70 includes at least one, and preferably a plurality of, cantilever locking segments 76. In the illustrated examples, the indexing adapter 70 is formed with four locking segments 76. The locking segments 76 could be formed by cutting one or more narrow radial slits into the top of the indexing adapter 70. Each locking segment 76 includes a spur 78 that extends inwardly from the central bore 72 and engages within the annular groove 45 of the shank 40, as best seen in
The aforementioned longitudinal stations of the collar 56 are established by annular channels 80 disposed about the external surface of the indexing adapter 70. Each adjacent pair of the channels 80 is separated by a respective annular rib 82. Depth number indicia may be disposed in or near the channels 80 to indicate a distance between the stop ring 58 and the apical end 48 corresponding to each longitudinal station. For example, using the previous exemplary pre-set drilling depths, the number “6” could be visibly embossed inside the first annular channel 80; the number “8” in the second annular channel 80; the number “10” in the third annular channel 80; the number “11.5” in the fourth annular channel 80; and the number “13” in the fifth/last annular channel 80.
One or more fingers 84 extend from the upper end of the collar 56, each carrying an inwardly extending prong or barb 86 designed to seat within a selected one of the annular channels 80. The annular channels 80 are each the same width which corresponds to the width of the barbs 86, and are therefore adapted to selectively receive the inwardly extending barbs 86 of the collar 56 as the collar 56 is moved from one longitudinal station to another. (Although, the width of the ribs 82 will vary depending on the predetermined spacing between the longitudinal stations.) The barbs 86 may be chamfered with camming faces to facilitate movement between the annular channels 80 as a user moves the collar 56 from one longitudinal station to another in setting and re-setting the depth stop. In this manner, the fingers 84 resiliently flex as the barbs 86 move into and out of registry with the annular channels 80 using moderately applied external force, and yet securely hold the collar 56 in each longitudinal station when the external force is removed.
One particular advantage of the indexing adapter 70 is that it can be installed on and removed from any osteotome 36 or drilling tool having at least one groove 45 in its shank 40 at a longitudinally coordinated location such that relative distance between the stop ring 58 and the apical end 48 will correspond to the intended drilling depth limit. Another advantage is that an adjustable position collar 56 can be utilized without forming multiple grooves in the tool shank 40, which would otherwise weaken the shank 40 with multiple stress-concentrating nodes that invite unwanted vibrations in use, and which add to manufacturing expense. And furthermore, multiple grooves in the tool shank 40 could increase the effort required post-operatively during the customary sterilization and cleaning processes.
The present invention, when configured with an indexing adapter 70, can be better suited to retrofit use across a wide range of drilling tools/burs marketed by different manufacturers. That is to say, in the case where manufacturers of different drilling tools form a groove 45 on their tool shank at different longitudinal positions relative to the apical end, or perhaps form grooves 45 of different shapes/sizes, it is possible to custom-manufacture an indexing adapter 70 for each manufacturer's specifications yet universally use the same collars 56 to fit across the spectrum of those various custom indexing adapters 70. For example, if Company X manufactures drilling tools and has a unique specification for the size and location of grooves 45 it forms on its tool shanks, and if Company Y manufactures drilling tools and has a consistently different specification for the size and location of grooves 45 it forms on its tool shanks, then an indexing adapter 70 specially fitting to Company X products can be offered, along with a different indexing adapter 70 specially fitting to Company Y products. And yet, the same collar 56 may be made to fit both types of indexing adapters 70.
Turning now to
The jig 88 is configured to be secured over a target drilling location, which in the exemplary dental context may be an edentulous jaw site 30. The target drilling location will naturally vary for each patient and according to the needed surgical procedure. In order to best cooperate with the stop gauge 54, the jig 88 includes a novel guide bushing 90 which establishes an alignment valley 92 that is sized and shaped so as to center the longitudinal axis A of the osteotome 36 with the target drilling location when used in combination with the stop gauge 54. The alignment valley 92 may be formed in various ways. For example, in the illustrated examples the alignment valley 92 is formed in the shape of a semi-cylinder having an internal diameter that is configured slightly larger than the outer diameter of the collar 56 to receive the high-speed rotating collar 56 with minimal friction and yet without excessive play/clearance. Although not shown in the drawings, it is contemplated that the alignment valley 92 may take other forms including, for example, the shape of a “V” or a squared notch or other open geometry.
The alignment valley 92 is oriented within the jig 88 to open toward the outer gum of the patient, thus providing maximum access and visibility into the edentulous jaw site 30 for the surgeon. That is to say, the half-cylinder shape of the bushing 90 provides the operator with superior visual and physical access to the edentulous jaw site 30. The alignment valley 92, which is not fully enclosed like in many prior art designs, allows substantially increased irrigation capacity to the osteotomy 36, as illustrated in
The alignment valley 92 may, optionally, include an internal ledge or abutment step 94. The abutment step 94 establishes an elevated surface configured to engage the spinning stop ring 58 of the collar 56 when the osteotome 36 has reached the desired drilling depth. In the case of a semi-cylindrical bushing 90, the abutment step 94 is semi-annular. One advantage of the abutment step 94 is to provide a perfectly smooth and perpendicular surface against which the rapidly rotating stop ring 58 will contact. Unlike the often imperfect surface of a patient's natural skin or exposed bone, the abutment step 94 is engineered to precision and will afford the surgeon certain and immediate haptic feedback when the desired drilling depth has been achieved. In cases where the collar 56 is made from a polymeric material, the smooth surface of the abutment step 94 may help avoid abrasion or distortion, thus extending the operating life of the stop gauge 54 and perhaps enabling re-use of the stop gauge 54 in one or more future surgical applications.
The elevation of the abutment step 94 above the patient's skin or bone at the edentulous jaw site 30 must be factored into the pre-set drilling depths established by the several longitudinal stations of the collar 56. For example, if the elevation of the abutment step 94 is 2 mm, then using the previous examples the actual drilling depths established by an indexing adapter 70 having five longitudinal stations will be 4, 6, 8, 9.5 and 11 mm, respectively. That is to say, the 2 mm elevation of the abutment step 94 (used as an example only) will subtract 2 mm from each of the otherwise predetermined drilling depths established by the indexing adapter 70 for the longitudinal stations of the collar 56. In
Of course, it is possible to design the indexing adapter 70 specifically for use with the guided surgical jig 88 so that the customary drilling depths are achieved without subtracting for the elevation of the annular abutment 94. Or alternatively, the depth number indicia may be designed to accommodate use of the stop gauge 54 with and without a jig 88 having an abutment step 94. For example, using the previous exemplary pre-set drilling depths, the numbers “6(4)” could be visibly embossed inside the first annular channel 80; the numbers “8(6)” in the second annular channel 80; the numbers “10(8)” in the third annular channel 80; the numbers “11.5(9.5)” in the fourth annular channel 80; and the numbers “13(11)” in the fifth/last annular channel 80. Of course, many alternatives are possible to accommodate the loss of drilling depth caused by the annular abutment 94.
The novel features of this invention are not limited to dental applications, but in fact are directly adaptable to many orthopedic applications as well.
The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. Furthermore, particular features of one embodiment can replace corresponding features in another embodiment or can supplement other embodiments unless otherwise indicated by the drawings or this specification.
This application claims priority to Provisional Patent Application No. 62/164,799 filed May 21, 2015, the entire disclosure of which is hereby incorporated by reference and relied upon.
Filing Document | Filing Date | Country | Kind |
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PCT/US16/33406 | 5/20/2016 | WO | 00 |
Number | Date | Country | |
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62164799 | May 2015 | US |