Bone transport device

Abstract

The present invention provides a bone transport device for transporting a bone piece. The bone transport device comprises an elongated shaft, a tubular housing enclosing the elongated shaft, a slider slidably mounted on the elongated shaft within the housing, an actuator configured to axially slide the slider along a slide portion of the elongated shaft, and a first cable portion fixedly connectable to a bone connector external to the tubular housing. The first cable portion is further fixedly connected to the slider within the tubular housing and the first cable portion is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the elongated shaft. The bone transport device is characterised in that the slide portion is circumscribed by a solid portion of the tubular housing and the first cable portion passes through a first aperture in a tubular wall of the tubular housing. The present invention further provides a bone transport device characterised in that the slider is rotationally fixed relative to the tubular housing. The present invention also provides a method of transporting a bone piece using the bone transport device.

Description

[0001] BONE TRANSPORT DEVICE

[0002] Field of the Invention

[0003] The present invention relates to a bone transport device, and particularly, although not exclusively, to a bone transport device for distraction osteogenesis.

[0004] Background

[0005] It is known to use bone transport devices such as bone lengthening nails to lengthen bones. Bone lengthening nails are implantable inside the medullary cavity of a bone and are used to lengthen the bone via distraction osteogenesis. Specifically, bone lengthening nails gradually separate, i.e. distract, bone fragments whereby the gap between the separated bone fragments is bridged by newly formed bone tissue. The formation of new bone tissue (i.e. osteogenesis) allows the bone to be lengthened.

[0006] Bone lengthening nails can have a tubular housing enclosing a screw mechanism consisting of an elongated lead screw inserted through a correspondingly threaded nut. In use, rotation of the lead screw along its longitudinal axis causes the nut to move axially along the length of the lead screw. The bone lengthening nail can be motorized such that the rotation of the lead screw is driven by a motor provided inside the tubular housing of the bone lengthening nail. The motor can be controlled externally to the patient’s body, for example via a magnetic field or an electronic signal transmitted to the motor.

[0007] A bone piece (fragment) can be attached to the nut either directly or indirectly (e.g. via one or more screws) such that the axial motion of the nut is transferred to the bone piece in order to transport it along the length of bone lengthening nail. Both types of attachment require one or more relatively large (e.g. elongated) slots in the tubular housing to expose a portion of the nut or to allow passage of the screws. For this reason, these types of bone lengthening nails are vulnerable to corrosion due to body fluids entering the inside of the tubular housing via the relatively large slot(s). Furthermore, the relatively large slot(s) in the tubular housing structurally weaken the tubular housing.

[0008] The present invention has been devised in light of the above considerations.

[0009] Summary of the Invention

[0010] In a first aspect, there is provided a bone transport device fortransporting a bone piece, the bone transport device comprising: an elongated shaft; a tubular housing enclosing the elongated shaft; a slider slidably mounted on the elongated shaft within the housing; an actuator configured to axially slide the slider along a slide portion of the elongated shaft; a first cable portion fixedly connectable to a bone connector external to the tubular housing, the first cable portion further being fixedly connected to the slider within the tubular housing; wherein the first cable portion is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the elongated shaft; the bone transport device being characterised in that the slide portion is circumscribed by a solid portion of the tubular housing and the first cable portion passes through a first aperture in a tubular wall of the tubular housing. In this way, upon axially sliding the slider along the elongated shaft, the sliding force is transmitted to the bone piece via the first cable portion and the bone connector, thereby axially transporting the bone piece. Thus, the bone transport device can be used to perform distraction osteogenesis.

[0011] As discussed above, entry of body fluids into the bone transport device is undesirable as it can create a corrosive environment inside the device. The solid portion of the tubular housing is unperforated such that the solid portion fluidly insulates the inside of the bone transport device from the outside of the bone transport device. Thus, by providing the tubular housing such that the solid portion circumscribes the slide portion of the elongated shaft, a risk of ingress of body fluids into the housing is reduced. Furthermore, circumscribing the slide portion with a solid portion of the tubular housing can increase the torsional stiffness and flexural strength of the tubular housing, thereby providing an overall structurally stronger and more robust bone transport device.

[0012] Optional features of the invention are discussed below. The invention includes the combination of the aspects and optional features described except where such a combination is clearly impermissible or expressly avoided.

[0013] As discussed above, the first cable portion is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the elongated shaft. To this end, in some examples, the first cable portion may be configured to transmit a tensile force such that movement of the slider along the slide portion of the elongated shaft pulls the bone connector. Additionally, or alternatively, the first cable portion may be configured to transmit a compressive force such that movement of the slider along the slide portion of the elongated shaft pushes the bone connector. In use, the bone connector is connected to the bone piece. Thus, movement of the bone connector transports the bone piece connected to the bone connector. Therefore, the first cable portion may be configured to transmit a compressive force and / or a tensile force to enable bone transport. In use, the first cable portion may be taut (i.e. under tension) to transmit the tensile force.

[0014] The slide portion of the elongated shaft is a portion of the elongated shaft along which the slider is configured to slide.

[0015] The first cable portion may loop through the first aperture and may comprise an internal portion extending substantially axially from the slider to the first aperture and an external portion extending proximal the solid portion of the housing. That is, the first cable portion may extend both internally and externally relative to the tubular housing, with its point of entry / exit on the tubular housing being the first aperture.

[0016] The external portion of the first cable portion may overlie the internal portion of the first cable portion in the radial direction such that the external portion is substantially parallel to the internal portion in an axial direction and a line extending along the radial direction transects both the external portion and the internal portion. The external portion may be spaced from the internal portion at least by the thickness of the tubular wall of the tubular housing extending therebetween in the radial direction.

[0017] By looping through the first aperture, the axial direction in which the internal portion extends can be opposite to the axial direction in which the external portion extends. That is, the first aperture may act as a turning point for the first cable portion such that the first cable portion reverses its extension direction along the axial direction at the first aperture. The first aperture may comprise a first turning edge around which the first cable portion loops in use. The first turning edge may be a convexly curved edge, such as a smooth convexly curved edge. Conveniently, this can facilitate sliding of the first cable portion over the smooth, convexly curved edge. In effect, the first turning edge may act as a pulley. The bone transport device may further comprise a first pulley wherein the first cable portion loops around the first pulley. The first pulley may be located in or at the first aperture. The first pulley may be provided as an alternative to the first turning edge of the first aperture to facilitate looping of the first cable portion through the first aperture. The first pulley may be mounted to the tubular housing via a first pin. The first pin may extend through the first pulley and across the first aperture.

[0018] The bone transport device may further comprise a second cable portion fixedly connectable to the bone connector external to the tubular housing. The second cable portion may be further fixedly connected to the slider within the tubular housing. The second cable portion may be configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the elongated shaft. The second cable portion may pass through a second aperture in the tubular wall of the tubular housing. Advantageously, the second cable portion may improve stability during bone transport so as to reduce a risk of the bone piece being displaced along a direction other than the axial direction, thereby reducing a risk of misalignment. Similar to the first cable portion, the second cable portion may be configured to transmit a compressive force and / or a tensile force to enable bone transport. In use, the second cable portion may be taut (i.e. under tension) to transmit the tensile force.

[0019] The second cable portion may loop through the second aperture. The second cable portion may comprise an internal portion extending substantially axially from the slider to the second aperture and an external portion extending proximal the solid portion of the tubular housing. That is, similarly to the first cable portion, the second cable portion may extend both internally and externally relative to the tubular housing, with its point of entry / exit on the tubular housing being the second aperture. The external portion of the second cable portion may overlie the internal portion of the second cable portion in the radial direction such that the external portion of the second cable portion is substantially parallel to the internal portion of the second cable portion in an axial direction and a line extending along the radial direction transects both the external portion and the internal portion. The external portion may be spaced from the internal portion at least by the thickness of the tubular wall of the tubular housing extending therebetween in the radial direction.

[0020] By looping through the second aperture, the axial direction in which the internal portion of the second cable portion extends can be opposite to the axial direction in which the external portion of the second cable portion extends. That is, the second aperture may act as a turning point for the second cable portion such that the second cable portion reverses its extension direction along the axial direction at the second aperture. The second aperture may comprise a second turning edge. The second turning edge may be convexly curved edge, e.g. a smooth convexly curved edge, around which the second cable portion loops in use. Conveniently, this can facilitate sliding of the second cable portion over the second turning edge. The second turning edge may be identical in shape and / or size to the first turning edge.

[0021] The bone transport device may further comprise a second pulley. The second pulley may be provided as an alternative to the second turning edge to facilitate looping of the second cable portion through the second aperture. The second cable portion may loop around the second pulley. The second pulley may be located in or at the second aperture. The second pulley may be identical to the first pulley. The second pulley may be mounted to the tubular housing via a second pin. The second pin may extend through the second pulley and across the second aperture.

[0022] The bone transport device may comprise a first sealing element located at the first aperture to seal the inside of the bone transport device (i.e. the inside of the tubular housing), thereby preventing entry of body fluids into the bone transport device. The first sealing element may seal against walls of the first aperture. The first sealing element may further seal against the first cable portion and / or the first turning edge and / or the first pulley.

[0023] The bone transport device may further comprise a second sealing element. The second sealing element may be located at the second aperture to seal the inside of the bone transport device (i.e. the inside of the tubular housing), thereby preventing entry of body fluids into the bone transport device. The second sealing element may seal against walls of the second aperture. The second sealing element may further seal against the second cable portion and / or the second turning edge and / or the second pulley.

[0024] The first cable portion and the second cable portion may together form a continuous cable loop fixedly connected to the slider and fixedly connectable to the bone connector. This configuration is referred to as a continuous loop configuration.

[0025] The first cable portion may be integral with or connected to the second cable portion. For example, the internal portion of the first cable portion may be integral with the internal portion of the second cable portion. Alternatively, the internal portion of the first cable portion may be connected to the internal portion of the second cable portion. For example, the internal portions of the first cable portion and the second cable portion may be connected to one another via crimping and / or clamping (e.g. via a compressive retainer such as a swage sleeve or a crimping connector) or by being tied in a knot. The internal portions of the first and second cable portions may be connected to one another at or inside the slider as discussed in more detail below.

[0026] The external portion of the first cable portion may be connected to the external portion of the second cable portion via crimping and / or clamping (e.g. via a compressive retainer such as a swage sleeve or a crimping connector or for example via an offset cam or a screw) or by being tied in a knot. In use, the external portions of the first and second cable portions may be connected to one another at or inside the bone connector as described in more detail below.

[0027] The first aperture and the second aperture may be axially spaced from one another by the solid portion of the tubular housing. That is, the solid portion of the tubular housing may be interposed between the first aperture and the second aperture in the axial direction, and the first aperture and the second aperture may lie on the same line along the axial direction.

[0028] The solid portion of the tubular housing may comprise a first channel on a first external surface thereof for receiving the external portion of the first cable portion. The first channel may be also for receiving the external portion of the second cable portion. That is, when the first cable portion and the second cable portion form a continuous loop, the first channel may receive the external portion of the continuous loop. The first channel may extend between the first aperture and the second aperture.

[0029] The first channel may extend along the axial direction. The first channel may be provided as an indentation (recess) formed in the first external surface of the tubular housing. The first channel may act as a groove for receiving and guiding the external portions of the first and second cable portions. In this way, the first channel can facilitate the external portions’ axial sliding along the first external surface of the tubular housing. The first channel is fluidly insulated from the inside of the tubular housing, thereby preventing entry of body fluid into the tubular housing via the first channel. Furthermore, providing the first channel as an indentation on the first external surface of the tubular housing (e.g. as opposed to a slot) can ensure that the first channel does not significantly structurally weaken the tubular housing, thereby improving the tubular housing’s structural strength. As an alternative to the continuous loop configuration, the first cable portion and the second cable portion may be arranged so as to be parallel to one another. This configuration is referred to as a parallel cable configuration. The internal portions of the first and second cable portions may extend parallel to one another and on diametrically opposite sides of the internal surface of tubular housing (and on diametrically opposite sides of the slider). The external portions of the first and second cable portions may be parallel to one another and extend on diametrically opposite sides of the tubular housing, external thereto.

[0030] The external portion of the first cable portion may be connected to the external portion of the second cable portion via crimping and / or clamping (e.g. via a compressive retainer such as a swage sleeve or a crimping connector or for example via an offset cam or a screw) or by being tied in a knot. In use, the external portions of the first and second cable portions may be connected to one another at or inside the bone connector as described in more detail below.

[0031] The second aperture may be diametrically opposed to the first aperture.

[0032] As in the continuous loop configuration described above, the solid portion of the tubular housing may comprise a first channel on the first external surface. The first channel may be for receiving the external portion of just the first cable portion. The first channel may extend from the first aperture. The solid portion of the tubular housing may further comprise a second channel on a second external surface thereof for receiving the external portion of just the second cable portion. The first external surface may be diametrically opposite the second external surface. The second channel may extend from the second aperture. The second channel may be diametrically opposed to the first channel.

[0033] Each of the first and second channel may extend along the axial direction. The first and second channel may be each provided as an indentation (recess) formed in the respective external surface of the tubular housing. The first and second channel may thus each act as a groove for receiving and guiding the respective external portion. In this way, the first and second channel can facilitate the external portion’s axial sliding along the respective external surface of the tubular housing. Each of the first and second channel is fluidly insulated from the inside of the tubular housing, thereby preventing entry of body fluid into the tubular housing via the first and second channel. Furthermore, providing the first and second channels as indentations on the external surface of the tubular housing (e.g. as opposed to a slot) can ensure that the first and second channel do not significantly structurally weaken the tubular housing, thereby improving the tubular housing’s structural strength.

[0034] The elongated shaft may comprise a threaded external surface. The slider may comprise a threaded surface. When the slider is slidably mounted on the elongated shaft, the threaded surface of the slider may engage with the threaded external surface of the elongated shaft such that rotation of the elongated shaft around its longitudinal axis results in the slider being axially slid along the elongated shaft. The axial direction is along the longitudinal axis of the elongated shaft. The threaded surface of the slider may correspond to (i.e. match) the threaded external surface of the elongated shaft.

[0035] The slider may comprise a shaft bore, and the elongated shaft may be slidably received within the shaft bore. When the slider comprises a threaded surface, the threaded surface may be an internal threaded surface of the shaft bore. Thus, the elongated shaft and the slider may together function as a lead screw mechanism.

[0036] The slider may further comprise a cable bore for receiving the first and / or second cable portion. The cable bore may be a single cable bore for receiving both the first and second cable portions. Alternatively, the cable bore may be a pair of cable bores comprising a first cable bore for receiving the first cable portion and a second cable bore for receiving the second cable portion. The slider may comprise at least one (e.g. a single) recess in a radially outer surface of the slider. For example, the recess may be a single recess exposing the single cable bore.

[0037] The slider may be attached to the first and / or second cable portions by threading the first and / or second cable portions through the first and / or second cable bores. The slider may be secured (e.g. axially fixed relative) to the first and / or second cable portions via at least one stopper fixedly attached to the first and / or second cable portions. The at least one stopper may be located in the / each recess. The at least one stopper may have a thickness larger than a diameter of the respective cable bore. That way, the at least one stopper can limit an amount by which the first and / or second cable portions are slidable relative to the slider within the respective cable bore by abutment against an opening to the cable bore inside the respective recess. The at least one stopper may be provided in the form of a bead threaded around and fixedly attached to the first and / or second cable portions, or a sleeve (e.g. a compressive sleeve) fixedly attached to the first and / or second cable portions. Alternatively, the at least one stopper may be a crimping connector. The at least one stopper may be two stoppers. Each stopper may be located proximal a respective opening to the respective cable bore, within the corresponding recess.

[0038] The / each cable bore may be parallel to the shaft bore. The / each cable bore may have a diameter sized such that the cable bore fits tightly around the respective cable portion(s) received therein. In the continuous loop configuration, the slider may have a single cable bore and a single recess exposing the cable bore. The cable bore may overlie the shaft bore of the slider in the radial direction such that the cable bore is parallel to the shaft bore and a line extending along the radial direction transects both the cable bore and the shaft bore. The internal portions of the first and second cable portions may be both received inside the cable bore of the slider, and the internal portions may be connected within the recess exposing the cable bore. The slider may be saddle shaped having a pair of elevated portions either side of the recess, with the cable bore transecting the slider’s elevated portions. In this way, the recess can provide a clearance for fixation of the slider to the first and second cable portions. The internal portions of the first and second cable portions may be attached to one another inside the recess via the at least one stopper for connection of the slider to the first and / or second cable portions. As discussed above, the at least one stopper may be a bead or a sleeve or a crimping connector e.g. sleeved around internal ends of the internal portions. In some examples, the internal ends of the internal portions may simply be tied to each other in a knot. In this case, the knot may provide the at least one stopper inside the recess.

[0039] In the parallel cable configuration, the slider may comprise the first cable bore and the second cable bore as described above. The first cable bore may be parallel to the second cable bore. The second cable bore may be parallel to the shaft bore of the slider. The shaft bore may be interposed between the first cable bore and the second cable bore along the radial direction. The first cable bore may be diametrically opposed to the second cable bore. The internal portions of the first and second cable portions may be fixedly attached to the slider by being clamped within the first cable bore and the second cable bore respectively.

[0040] As discussed above, in either of the continuous cable configuration and the parallel cable configuration, the external portions of the first cable portion and the second cable portion may be connected to one another. The external portions of the first cable portion and the second cable portion may be connected at or inside the bone connector. The connection between the first cable portion and the second cable portion (e.g. between their respective external portions) may be configured such that the connection becomes at least partially released upon application of a tensile force equal to or exceeding a predetermined tensile force. The predetermined tensile force may be applied to the first and / or second cable portion. The predetermined tensile force may be less than a tensile force associated with (i.e. corresponding to) a tensile strength of the first cable portion and / or the second cable portion. A tensile force associated with / corresponding to a tensile strength is the force which, if reached and / or exceeded, results in fracture of the cable portion that is characterised by the tensile strength. The tensile strengths of the first and second cable portions may be equal (e.g. when the internal portions of the first and second cable portions are integral).

[0041] Configuring the connection between the first and second cable portions so as to become at least partially released upon application of a tensile force equal to or less than a tensile force corresponding to a tensile strength of the first cable portion and / or the second cable portion can help prevent breakage of the first and / or second cable portions, e.g. when the slider is jammed causing excessive strain to be applied to the cable portions. In this way, the connection between the external portions of the first and second cable portions can act as a mechanical fuse.

[0042] For example, the connection may be at least partially released by allowing a degree of relative motion between the external portions of the first cable portion and the second cable portion. The relative motion may for example cause the external portions to slide relative to one another, thereby loosening the tension in the first cable portion and / or the second cable portion. Alternatively, the relative motion may cause the connection between the external portions to become completely released (i.e. to break). Thus, the connection between the external portions of the first and second cable portions can allow a predetermined amount of give to absorb / dissipate excessive strain in the first and / or second cable portions, thereby reducing a risk of cable breakage.

[0043] In some examples, the first cable portion may be connected to the second cable portion via a compressive retainer. That is, the first cable portion may be connected to the second cable portion by crimping and / or clamping the compressive retainer around portions (e.g. external ends of the external portions) of the first and second cable portions. The compressive retainer may exert a compressive force on the portions of the first and second cable portions retained therein. When the bone connector comprises a holder, the holder may support the compressive retainer and the portions of the first and second cable portions retained therein. The compressive retainer may extend along the axial direction of the bone transport device.

[0044] The compressive retainer may be a swage sleeve. Thus, in some examples, external ends of the external portions of the first and second cable portions may be attached to one another by swaging. Specifically, the external ends may be attached together via the swage sleeve sleeved around the external ends. The external ends may be fed through the compressive retainer (e.g. swage sleeve) in opposite directions. The swage sleeve may be swaged and / or crimped using an appropriate tool to connect / fixedly attach the external portions of the first and second cable portions together. The swage sleeve may be for example an oval swage sleeve, or an hourglass swage sleeve.

[0045] Upon application of a tensile force equal to or exceeding the predetermined tensile force, the first and second cable portions (e.g. their external portions) may slide relative to each other within the swage sleeve to loosen the tension in the first and / or second cable portions either while remaining connected, or while sliding out of the swage sleeve to break the connection.

[0046] The bone connector may comprise at least one cable receptacle configured to at least partially receive the first cable portion and / or the second cable portion. The at least one cable receptacle may be insertable into the bone piece. The at least one cable receptacle may be configured to at least partially receive external ends of the external portions of the first and / or second cable portions. For example, the bone connector may comprise a single cable receptacle configured to receive external ends of both the first and the second cable portions. Alternatively, the at least one cable receptacle may be a pair of cable receptacles comprising a first cable receptacle configured to at least partially receive an external end of the first cable portion and a second cable receptacle configured to at least partially receive an external end of the second cable portion.

[0047] In addition to at least partially receiving the first and / or second cable portions, the / each cable receptacle may be further configured to retain the first cable portion and / or the second cable portion.

[0048] The / each cable receptacle may be a channel extending through the bone connector. The / each cable receptacle may extend perpendicularly to the axial direction. Alternatively, the / each cable receptacle may be angled relative to the axial direction. In some examples, the external ends of the first cable portion and the second cable portion may be attached together via clamping and / or crimping, e.g. inside the / each cable receptacle.

[0049] The / each cable receptacle may be provided with a respective plug insertable therein. Thus, the external ends of the first and second cable portions may be clamped between a respective internal surface of the / each cable receptacle and an external surface of the respective plug. The / each cable receptacle may comprise an internal threaded surface. The / each plug may comprise a threaded external surface configured to engage with the threaded internal surface of the respective cable receptacle. Thus, the external ends of the first and second cable portions may be fixedly attached inside the / each cable receptacle by screwing the / each plug inside the respective cable receptacle so as to clamp the external ends therein. The / each plug may be a grub screw.

[0050] The bone transport device may further comprise one or more cable retainers, each cable retainer being insertable into a respective cable receptacle such that in use the / each cable retainer is interposed between portions of the first and / or second cable portions received within the respective cable receptacle and the respective plug inserted therein. The / each cable retainer may comprise one or more projections each engageable with a respective groove formed in the internal surface of the respective cable receptacle. The / each cable retainer can thus help retain the respective cable portion(s) in place within the respective cable receptacle by pressing thereon. The / each cable retainer can also space the cable portions(s) from the respective plug. Conveniently, this prevents the plug from directly exerting torque on the cable portion(s) while the plug is being screwed into the respective cable receptacle, thereby reducing a risk of cable damage.

[0051] In other examples, the external portions of the first and second cable portions may be attached to each other by tying their respective external ends together in a knot, e.g. inside the single cable receptacle, or over the pair of cable receptacles.

[0052] The bone connector may further comprise a holder for supporting the external ends of the external portions of the first and second cable portions. The holder may open to the / each cable receptacle such that the external ends can be fed to the holder through the / each cable receptacle. The holder may define a channel for receiving the external ends of the first and second cable portions. The channel may be an axially extending channel. The channel may be an open channel (i.e. such that the channel supports the external ends from underneath and laterally, but does not fully enclose the external ends). The holder may further comprise a recess transecting the channel so as to expose an inner portion of the channel in use supporting the external ends. The recess may extend perpendicularly to the channel. The recess may thus provide access to the external ends of the first and second cable portions, e.g. to facilitate attachment of the external ends to one another e.g. in one of the ways described above. In some examples, the recess may transect the channel such that the holder comprises prongs (e.g. four prongs) to support the external ends. The prongs may extend along a longitudinal axis of the bone connector (e.g. a longitudinal axis of the / each cable receptacle). The prongs may extend perpendicularly to the axial direction of the bone transport device, and optionally away from the / each cable receptacle. When the external ends of the external portions of the first and second cable portions are connected to one another via a compressive retainer (such as swage sleeve), the holder may be configured to support (e.g. retain) the compressive retainer in place.

[0053] In a second aspect, there is provided a bone transport device for transporting a bone piece, the bone transport device comprising: an elongated shaft; a tubular housing enclosing the elongated shaft, the tubular housing comprising a first aperture in a tubular wall thereof; a slider slidably mounted on the elongated shaft within the housing; an actuator configured to axially slide the slider along a slide portion of the elongated shaft; a first cable portion fixedly connectable to a bone connector external to the tubular housing, the first cable portion being fixedly connected to the slider within the tubular housing; wherein the first cable portion passes through the first aperture and is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the shaft; the bone transport device being characterised in that the slider is rotationally fixed relative to the tubular housing.

[0054] Advantageously, the bone transport device of the second aspect helps reduce a risk of the first and / or second loop portions twisting upon rotation of the slider relative to the tubular housing which can lead to misalignment of the bone piece being transported, thereby hindering the distraction osteogenesis process.

[0055] Features of the first aspect and the second aspect may be combined.

[0056] The slider may be rotationally fixed relative to the tubular housing. That is, the slider may be prevented from rotating around the elongated shaft. Advantageously, this can reduce a risk of the slider becoming jammed inside the tubular housing and / or the bone piece becoming misaligned during bone transport.

[0057] For example, a radially outer surface of the slider may be configured for abutment and / or engagement with a portion of the inner surface of the tubular housing. Thus, rotation of the slider relative to the axial direction can be prevented via a frictional interaction between the slider and the tubular body.

[0058] Specifically, the slider may have a substantially oval transverse cross section with a maximum major diameter (i.e. the maximum extension of the major axis of the oval transverse cross section) that is greater than the minimum diameter of the transverse cross section of the tubular housing. The transverse cross section is in a plane perpendicular to the shaft bore of the slider.

[0059] The substantially oval transverse cross section may be elliptical or egg-shaped or stadium-shaped. In this way, the abutment and / or engagement of the radially outer surface of the slider with the portion of the inner surface of the tubular housing can be enabled by the ovate shape of the slider. The tubular housing may also have a substantially oval transverse cross-section. Specifically, the tubular housing may have a transverse cross section which is matchingly shaped to the transverse cross section of the slider. In this case, the minimum diameter of the transverse cross section of the tubular housing is the minor diameter (i.e. the extension of the minor axis) of the oval cross section. Alternatively, the slider may have a substantially circular transverse cross section. In this case, the minimum diameter is the diameter of the transverse cross section.

[0060] Additionally, or alternatively, the bone transport device may comprise a fixing element which rotationally fixes the slider relative to the tubular housing. The fixing element may be located on the slider. For example, the fixing element may be located on a radially outer surface of the slider. Alternatively, the fixing element may be located on the tubular housing. For example, the fixing element may be located on an inner surface of the tubular housing.

[0061] In some examples, the fixing element may be a lug and the bone transport device may further comprise a cooperating groove. For example, the lug may be on one of the inner surface of the tubular housing and the radially outer surface of the slider, and the groove may be on the other of the inner surface of the tubular housing and the radially outer surface of the slider. The lug and groove may each extend axially along the slide portion of the elongated shaft. When the lug is provided on the inner surface of the tubular housing, the lug may extend axially along the entire / a portion of the axial length of the slide portion of the tubular housing. The cooperating groove may extend axially along the entire / a portion of the axial length of the slider. The lug may be provided as a taut wire fixedly attached (e.g. welded) to the inner surface of the tubular housing. For example, the wire may be welded at both of its ends to the inner surface of the tubular housing. The wire may have a diameter of around 0.5mm.

[0062] Additionally, or alternatively, the shaft bore may be radially offset from the slider’s longitudinal axis. In addition to rotationally fixing the slider relative to the housing, this also facilitates the slider having a substantially oval transverse cross section as described above. When the slider has a substantially oval transverse cross section, the shaft bore may be spaced from the longitudinal axis of the slider passing through the centre of the oval cross section along the major diameter of the oval cross section.

[0063] The tubular housing of the first and / or second aspect may have a circular transverse cross-section (i.e. in a transverse plane perpendicular to the axial direction). Alternatively, the tubular housing may have a substantially oval transverse cross-section. The substantially oval transverse cross section may be elliptical or egg-shaped or stadium-shaped. The tubular housing may have a transverse cross-section shaped to substantially match a shape of the transverse cross section of the slider (i.e. the cross section taken in a plane perpendicular to the shaft bore).

[0064] The bone transport device of the first or second aspect may further comprise the bone connector. The bone connector may be as described with reference to the first aspect.

[0065] All components of the bone transport device of the first or second aspect may be formed of biocompatible materials, e.g. bio-compatible metals.

[0066] The actuator in the first or second aspect may be provided by a motor configured to drive the elongated shaft so as to cause the slider to axially slide along the slide portion of the elongated shaft. More specifically, the actuator may be a motor configured to rotate the elongated shaft around its longitudinal axis. As discussed above, when the elongated shaft and the slider comprise correspondingly threaded surfaces, rotation of the elongated shaft causes the slider to axially slide along the slide portion of the elongated shaft. In some examples, the motor may be an electric motor. The motor may be driven remotely. Specifically, the motor may be driven (energised) using a device external to the patient’s body. For example, the motor may be driven via electromagnetic induction. Specifically, electricity may be induced inside the electric motor within the bone transport device by a changing magnetic field applied external to the patient’s body. Alternatively, the motor may be driven by an electronic signal transmitted thereto.

[0067] In a third aspect, there is provided a method of transporting a bone piece using the bone transport device of the first or second aspect, the bone transport method comprising: connecting a first axial end of the bone transport device to a first bone portion; connecting a second axial end of the bone transport device to a second bone portion; performing corticotomy on the first bone portion to obtain the bone piece; fixedly connecting the bone connector to the bone piece; and axially sliding the slider along the slide portion of the elongated shaft to transport the bone piece.

[0068] Fixedly connecting the bone connector to the bone piece may include at least partially inserting the bone connector into the bone piece.

[0069] The method may comprise drilling one or more openings into the bone piece for insertion of the bone connector therein. For example, the method may involve drilling the one or more openings using a suitable tool such as a jig. The method may include drilling the one or more openings perpendicularly to the axial direction, or at an angle thereto.

[0070] The method may include threading the external portion(s) of the first and / or second cable portions through the bone connector.

[0071] When the bone transport device comprises the first cable portion and the second cable portion, the method may further comprise fixedly connecting the external portions of the first and second cable portions to one another and / or to the bone connector.

[0072] For example, the method may comprise crimping and / or clamping the external portions to one another, e.g. by sleeving a compressive retainer (such as a swage sleeve) around the external ends, and crimping it or swaging it such that the compressive retainer exerts a compressive force on the external portions to retain them therein.

[0073] Alternatively, the method may comprise tying the external ends of the external portions of the first and second cable portions together in a knot, e.g. over an opening of the / each cable receptacle.

[0074] When the bone transport device comprises the one or more plugs insertable in the one or more cable receptacles, the method may include threading the external portion(s) of the first and / or second cable portions through the / each cable receptacle, and inserting the / each plug in its respective cable receptacle to clamp the / each external portion between the internal surface of the respective cable receptacle and the external surface of the plug inserted therein. When the / each cable receptacle and the / each plug comprise correspondingly threaded surfaces, the method may further include screwing the / each plug inside its respective cable receptacle to clamp the respective external portion(s) therein.

[0075] When the bone transport device comprises one or more cable retainers, the method may further comprise a step of inserting the / each cable retainer in a respective cable receptacle prior to inserting and / or screwing the respective plug in the cable receptacle. Summary of the Figures

[0076] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0077] Fig. 1 schematically shows a bone transport device implanted into a patient’s limb;

[0078] Fig. 2 schematically shows a cross sectional view of a part of the bone transport device of Fig. 1 ;

[0079] Fig. 3 schematically shows a side view of a part of the bone transport device of Fig. 2;

[0080] Fig. 4 schematically shows a perspective sectional view of a first aperture on the bone transport device of Fig. 3;

[0081] Fig. 5 schematically shows a partial perspective view of a bone transport device comprising a pulley and a magnified view showing the pulley;

[0082] Fig. 6 schematically shows a partial perspective view of a bone transport device comprising a pulley, and a magnified view of the pulley;

[0083] Fig. 7 schematically shows a top sectional view of a bone transport device according to a parallel cable configuration;

[0084] Fig. 8 schematically shows an exploded view of the bone transport device of Fig. 7;

[0085] Fig. 9 schematically shows a transverse cross-sectional view of the bone transport device of Fig. 7;

[0086] Fig. 10A schematically shows a side sectional view of a part of the bone transport device of Fig. 7, and Fig. 10B schematically shows a magnified view of the part of the device shown in Fig. 10A;

[0087] Fig. 11 schematically shows a side sectional view of a bone transport device according to a continuous loop configuration;

[0088] Fig. 12 schematically shows an exploded view of the bone transport device of Fig. 11 ;

[0089] Fig. 13 schematically shows side sectional views of portions of the bone transport device of Fig. 11 ;

[0090] Figs 14A, 14B, 14C, and 14D schematically show respectively a front sectional view, a side sectional view, and a first and second perspective views of a slider for use with the bone transport device of Fig. 11 ;

[0091] Fig. 15 schematically shows a side sectional view of a bone piece connected to a bone transport device via a bone connector;

[0092] Fig. 16 schematically shows a top perspective view of bone connector inserted into a bone piece;

[0093] Fig. 17 schematically shows a side sectional view of bone connector inserted into a bone piece; Fig. 18 schematically shows a partial perspective view of a bone transport device according to the parallel cable configuration, the bone transport device comprising a bone connector;

[0094] Fig. 19 schematically shows a perspective view of a bone transport device, a jig, and a bone piece;

[0095] Fig. 20 schematically shows a partial perspective view of a bone piece attached a bone transport device according to the parallel cable configuration;

[0096] Figs 21 A, 21 B, 21 C, 21 D, and 21 E schematically show respectively a perspective view, a side view, a top view, a side view, and a side sectional view of a bone connector;

[0097] Fig. 22 schematically shows a partial perspective view of a bone transport device; and

[0098] Fig. 23A, Fig. 23B, 23C schematically show respective front sectional views of a tubular housing of a bone transport device.

[0099] Detailed Description of the Invention

[0100] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0101] Embodiments of a bone transport device 1 according to the present invention are discussed with reference to Figs 1-23C.

[0102] With reference to Fig. 1 , the bone transport device 1 is implantable inside the medullary cavity of a bone

[0103] 9. Specifically, a first axial end of the bone transport device 1 is attachable to a first bone portion 9a of the bone 9 via one or more bone screws 14, and a second axial end of the bone transport device 1 is attachable to a second bone portion 9b of the bone 9 via another set of one or more bone screws 14. A bone piece 70 is obtained by performing corticotomy on the first bone portion 9a. The bone transport device 1 is attachable to the bone piece 70 via a bone connector 61 (see e.g. Fig. 8).

[0104] With reference for example to Fig. 7, the bone transport device 1 comprises an elongated shaft 2, a tubular housing 10 enclosing the elongated shaft 2, and a slider 20 slidably mounted on the elongated shaft 2 within the housing 10. The bone transport device 1 further comprises a first cable portion 4 fixedly connectable to a bone connector 60 external to the tubular housing 10, the first cable portion 4 further being fixedly connected to the slider 20 within the tubular housing 10. The bone transport device 1 further comprises a second cable portion 5 fixedly connectable to the bone connector 60 external to the tubular housing 10. The second cable portion 5 is fixedly connected to the slider 20 within the tubular housing

[0105] 10. The first cable portion 4 passes through a first aperture 40 in a tubular wall of the tubular housing 10 and the second cable portion 5 passes through a second aperture 50 in the tubular wall of the tubular housing 10. Each of the first 4 and second 5 cable portions is configured to transmit a sliding force to the bone connector 60 upon movement of the slider 20 along a slide portion of the elongated shaft 2. Specifically, the first cable portion 4 and the second cable portion 5 are each configured to transmit a compressive force and / or a tensile force to enable bone transport. In use, the first 4 and / or second cable portion 5 may be taut (i.e. under tension) to transmit the tensile force. With reference to Fig. 8 for example, the slide portion of the elongated shaft 2 is circumscribed by a solid portion 10a of the tubular housing 10. The solid portion 10a of the tubular housing 10 is unperforated such that the solid portion 10a fluidly insulates the inside of the bone transport device 1 from the outside of the bone transport device 1 , thereby reducing a risk of ingress of body fluids inside the tubular housing 10. The slider 20 comprises a shaft bore 22 (see e.g. Figs 14A-14D), and the elongated shaft 2 is slidably received within the shaft bore 22. The elongated shaft 2 comprises a threaded external surface and the shaft bore 22 comprises an internal threaded surface such that when the slider 20 is slidably mounted on the elongated shaft 2, the threaded surface of the slider 20 engages with the threaded external surface of the elongated shaft 2. Thus, rotation of the elongated shaft 2 around its longitudinal axis results in the slider 20 being axially slid along the elongated shaft 2. Thus, the elongated shaft 2 and the slider 20 together function as a lead screw mechanism.

[0106] With reference to Fig. 2, the bone transport device 1 is motorized such that the bone transport device 1 comprises a motor 80 to drive transport of the bone piece 70 along the length of the bone transport device 1 . The motor 80 is enclosed within the tubular housing 10. The motor 80 is configured to rotate the elongated shaft 2 around its longitudinal axis to cause the slider 20 to axially slide along the slide portion of the elongated shaft 2. The motor 80 is configured to be driven remotely. The motor 80 comprises an input shaft 71 , a magnet 75, a gearbox 77, an output shaft 72, as well as bearings 74, thrust bearings 73, and seals 78. The motor 80 is driven using a device (not shown) external to the patient’s body via electromagnetic induction. Specifically, a changing magnetic field applied externally to the patient’s body causes the magnet 75 inside the motor 80 to move, e.g. to rotate, thereby driving the input 71 and output 72 shafts. The generated motion is transmitted to the elongated shaft 2 to rotate it along its longitudinal axis.

[0107] The elongated shaft 2 may be an M3 screw (i.e. the elongated shaft 2 may have a diameter of around 3mm). In another example, the elongated shaft 2 may be an M4 screw (i.e. the elongated shaft 2 may have a diameter of around 4mm).

[0108] The first 4 and / or second 5 cable portions may each have a diameter from 0.5mm to 1 ,2mm. The first 4 and / or second 5 cable portions may be each formed of any one or any combination of: steel (e.g. stainless steel), plastics materials, e.g. nylon, or polyesters such as Dacron™, or polyamides, or polyethylene, or aramid fibres such as Kevlar™, or composite materials such as Dyneema™ or Spectra™. The first 4 and / or second 5 cable portions may be each formed of a fibre polyblend. The first 4 and / or second 5 cable portions may be each reinforced, e.g. the first 4 and / or second 5 cable portions may be each formed of reinforced plastics.

[0109] As mentioned above, the first cable portion 4 passes through the first aperture 40 and the second cable portion 5 passes through the second aperture 50. With reference to Fig. 7 for example, the first cable portion 4 loops through the first aperture 40 and comprises an internal portion 4a extending substantially axially from the slider 20 to the first aperture 40 and an external portion 4b extending proximal the solid portion 10a of the housing 10. That is, the first cable portion 4 extends both internally and externally relative to the tubular housing 10, with its point of entry / exit on the tubular housing 10 being the first aperture 4.

[0110] Similarly, the second cable portion 5 loops through the second aperture 50. The second cable portion 5 comprises an internal portion 5a extending substantially axially from the slider 20 to the second aperture 50 and an external portion 5b extending proximal the solid portion 10a of the tubular housing 10. The external portions 4b, 5b of the first 4 and second 5 cable portions respectively overlie the internal portions 4a, 5a of the first 4 and second 5 cable portions in the radial direction such that the external portions 4b, 5b are substantially parallel to the respective internal portions 4a, 5a in the axial direction and a line extending along the radial direction transects both the external portions and the internal portions. The external portions 4b, 5b are spaced from the internal portions 4a, 5a at least by the thickness of the tubular wall of the tubular housing 10 extending therebetween in the radial direction. Each of the first 40 and the second 50 aperture acts as a turning point for the first cable portion 4 and the second cable portion 50 respectively such that the first cable portion 4 reverses its extension direction along the axial direction at the first aperture 40 and the second cable portion 5 reverses its extension direction along the axial direction at the second aperture 50.

[0111] The structure of the first 40 and second apertures 50 is discussed with reference to Figs 3-6. Figs 3-6 only show the first aperture 40. However, the second aperture 50 may be structurally identical to the first aperture 40, or the second aperture 50 may have any combination of features of the first aperture 40.

[0112] With reference to Fig. 4, the first aperture 40 comprises a first turning edge 41 around which the first cable portion 4 loops in use. The first turning edge 41 is a convexly curved edge and more specifically a smooth convexly curved edge. Conveniently, this can facilitate sliding of the first cable portion 4 over the smooth, convexly curved edge 41 . In effect, the first turning edge 41 acts as a pulley. As discussed above, even though not shown in the figures, the second aperture 50 can also comprise a second turning edge 51 around which the second cable portion 5 loops in use. The second turning edge 51 can also be a smooth, convexly curved edge.

[0113] With reference to Figs 5 and 6, the bone transport device 1 can further comprise a first pulley 42 wherein the first cable portion 4 loops around the first pulley. The first pulley 42 is located in the first aperture 40. In this example, the first pulley 42 is provided as an alternative to the first turning edge 41 of the first aperture 40 to facilitate looping of the first cable portion 4 through the first aperture. The first pulley 42 is mounted to the tubular housing 10 via a first pin 44. The first pin 44 extends through the first pulley 42 and across the first aperture 40. As discussed above, even though not shown in the figures, the bone transport device 1 can also comprise a second pulley 52 located in the second aperture 50. The second pulley 52 may be mounted to the tubular housing 10 via a second pin 54. The second pin 54 may extend through the second pulley 52 and across the second aperture 50.

[0114] The bone transport device 1 may comprise a first sealing element (not shown) located at the first aperture 40 to seal the inside of the tubular housing 10. The first sealing element may seal against walls of the first aperture 40 and / or against the first cable portion 4 and / or the first turning edge 41 and / or the first pulley 42. The bone transport device 1 may comprise a second sealing element (not shown) located at the second aperture 50 to seal the inside of the tubular housing 10. The second sealing element may seal against walls of the second aperture 50 and / or against the second cable portion 5 and / or the second turning edge 51 and / or the second pulley 52.

[0115] The bone transport device 1 can be configured in different ways. For example, the bone transport device 1 may be configured in a parallel cable configuration or in a continuous loop configuration. The parallel cable configuration is discussed below with reference to Figs 7-10B. The continuous loop configuration is discussed with reference to Figs 11-13.

[0116] In the parallel cable configuration, the first cable portion 4 and the second cable portion 5 are arranged so as to be parallel to one another. That is, the internal portions 4a, 5a of the first 4 and second 5 cable portions extend parallel to one another and on diametrically opposite sides of the internal surface of tubular housing (and on diametrically opposite sides of the slider 20). The external portions 4b, 5b of the first 4 and second 5 cable portions are parallel to one another and extend on diametrically opposite sides of the tubular housing 10, external thereto. The second aperture 50 is diametrically opposed to the first aperture 40. In the example of Figs 10A and 10B, the first aperture 40 and the second aperture 50 each comprise a respective turning edge 41 , 42, as discussed in detail above.

[0117] The solid portion 10a of the tubular housing 10 comprises a first channel 11 for receiving the external portion 4b of just the first cable portion 4. The first channel 11 extends from the first aperture 40. The solid portion 10a further comprises a second channel 12 for receiving the external portion 5b of just the second cable portion 5. The second channel 12 extends from the second aperture 50. The first channel 11 is diametrically opposed to the second channel 12. Each of the first 11 and second 12 channel extends along the axial direction. Each of the first 11 and second 12 channel is provided as an indentation (recess) formed in the respective external surface of the tubular housing 10. The first 11 and second 12 channels thus each act as a groove for receiving and guiding the respective external portion 4b, 5b. Each of the first 11 and second 12 channel is fluidly insulated from the inside of the tubular housing 10.

[0118] With reference to Figs 7 and 8, the external portion 4b of the first cable portion 4 is connected to the external portion 5b of the second cable portion 5 via a compressive retainer s such as a swage sleeve or a crimping connector. In use, the external portions 4b, 5b of the first 4 and second 5 cable portions are connected to one another at the bone connector 60.

[0119] As shown in Fig. 9, the slider 20 can be rotationally fixed relative to the tubular housing 10 via a lug 7 so as to prevent the slider from rotating relative to the axial direction. In this example, the lug 7 is provided on the inner surface of the tubular housing 10. The lug 7 is received within a cooperating groove 8. The groove 8 is formed on the radially outer surface of the slider 20. The lug 7 and groove 8 each extend axially along the slide portion of the elongated shaft 2. The lug 7 may be provided as a taut wire fixedly attached (e.g. welded) to the inner surface of the tubular housing 10. For example, the wire may be welded at both of its ends to the inner surface of the tubular housing 10. The wire may have a diameter of around 0.5mm.

[0120] As best seen in Figs 9 and 10A, in addition to the shaft bore 22, the slider 20 comprises a pair of cable bores 21a, 21 b comprising a first cable bore 21a for receiving the first cable portion 4 and a second cable bore 21 b for receiving the second cable portion 5. The first cable bore 21a is parallel to the second cable bore 21 b. The second cable bore 21 b is parallel to the shaft bore 22 of the slider 20. The shaft bore 22 is interposed between the first cable bore 21a and the second cable bore 21 b along the radial direction. The first cable bore 21a is diametrically opposed to the second cable bore 21 b. The internal portions 4a, 5a of the first 4 and second 5 cable portions are fixedly attached to the slider 20 by being clamped within the first cable bore 21a and the second cable bore 21 b respectively.

[0121] Each cable bore may have a diameter sized such that the cable bore fits tightly around the respective cable portion(s) received therein.

[0122] Turning to the continuous loop configuration discussed with reference to Figs 11-13, the first cable portion 4 and the second cable portion 5 together form a continuous cable loop fixedly connected to the slider 20 and fixedly connectable to the bone connector 60.

[0123] With reference to Fig. 11 , the internal portion 4a of the first cable portion 4 is integral with the internal portion 5a of the second cable portion 5. The external portion 4b of the first cable portion 4 is connected to the external portion 5b of the second cable portion 5 at or inside the bone connector 60 as described in more detail below. The first aperture 40 and the second aperture 50 are axially spaced from one another by the solid portion 10a of the tubular housing 10. That is, the solid portion 10a of the tubular housing 10 is interposed between the first aperture 40 and the second aperture 50 in the axial direction, and the first aperture 40 and the second aperture 50 lie on the same line along the axial direction.

[0124] As in the parallel cable configuration, the solid portion 10a of the tubular housing 10 comprises a first channel 11 on the external surface of the tubular housing 10. However, in the continuous loop configuration, the first channel 11 is for receiving the external portion 4b of the first cable portion 4 and the external portion 5b of the second cable portion 5. That is, in use the first channel 11 receives the external portion of the continuous loop. The first channel 11 extends axially between the first aperture 40 and the second aperture 50.

[0125] The first channel 11 is provided as an indentation (recess) formed in the first external surface of the tubular housing 10. The first channel 11 acts as a groove for receiving and guiding the external portions 4b, 5b of the first 4 and second 5 cable portions. In this way, the first channel 11 can facilitate the external portions’ axial sliding along the first external surface of the tubular housing. The first channel 11 is fluidly insulated from the inside of the tubular housing 10, thereby preventing entry of body fluid into the tubular housing 10 via the first channel 11 . The slider may further comprise a cable bore for receiving the first and second cable portion. The cable bore may be a single cable bore for receiving both the first and second cable portions. The slider may comprise a single recess in a radially outer surface of the slider exposing the cable bore.

[0126] With reference to Figs 14A-14D, the slider 20 has a single cable bore 21 and a single recess 23 exposing the cable bore. The cable bore 21 overlies the shaft bore 22 of the slider in the radial direction such that the cable bore 21 is parallel to the shaft bore 22 and a line extending along the radial direction transects both the cable bore and the shaft bore. The internal portions 4a, 5a of the first 4 and second 5 cable portions are integral with one another and are both received inside the cable bore 21 of the slider 20. The slider 20 is saddle shaped having a pair of elevated portions 20a, 20b either side of the recess 23, with the cable bore 21 transecting the slider’s elevated portions 20a, 20b. In this way, the recess 23 can provide a clearance for fixation of the slider 20 to the first 4 and second 5 cable portions. The slider 20 is secured to the first 4a and second 5a cable portions via a stopper 24 fixedly attached to the first 4 and second 5 cable portions (which are integral with each other in this example). The stopper 24 is located in the recess 23. The stopper 24 has a thickness larger than a diameter of the cable bore 21 . That way, the stopper 24 can limit an amount by which the first 4 and second 5 cable portions are slidable relative to the slider 20 within the cable bore 21 by abutment against an opening to the cable bore 21 inside the recess 23. The stopper 24 is provided in the form of a bead threaded around and fixedly attached to the first 4 and second 5 cable portions. Alternatively, the stopper 24 may be a crimping connector, or a sleeve (e.g. a compressive sleeve) fixedly attached to the first 4 and second 5 cable portions.

[0127] In both the parallel cable configuration, and the continuous loop configuration, the external portions 4b, 5b of the first 4 and second 5 cable portions may be attached to one another at or inside the bone connector 60. There are multiple ways of attaching the external portions 4b, 5b to one another and / or to the bone connector 60. Examples of these are discussed with reference to Figs 15-21 E.

[0128] In some examples, the connection between the first cable portion 4 and the second cable portion 5 (i.e. between their respective external portions 4b, 5b) is configured such that the connection becomes at least partially released upon application of a tensile force equal to or exceeding a predetermined tensile force. The predetermined tensile force may be applied to the first 4 and / or second 5 cable portion. The predetermined tensile force may be less than a tensile force associated with (i.e. corresponding to) a tensile strength of the first cable portion 4 and / or the second cable portion 5. In some examples, the tensile strengths of the first 4 and second 5 cable portions are equal (e.g. when the internal portions 4a, 5a of the first 4 and second 5 cable portions are integral).

[0129] In some examples, the connection may be at least partially released by allowing a degree of relative motion between the external portions 4b, 5b of the first cable portion 4 and the second cable portion 5. The relative motion can cause the external portions 4b, 5b to slide relative to one another, thereby loosening the tension in the first cable portion 4 and / or the second cable portion 5. Alternatively, the relative motion can cause the connection between the external portions 4b, 5b to become completely released (i.e. to break). Thus, the connection between the external portions 4b, 5b of the first 4 and second 5 cable portions can allow a predetermined amount of give to absorb / dissipate excessive strain in the first and / or second cable portions, thereby reducing a risk of cable breakage.

[0130] With reference to Figs 18-21 E, the first cable portion 4 can be connected to the second cable portion 5 via a compressive retainer 6. That is, the first cable portion 4 may be connected to the second cable portion 5 by crimping and / or clamping the compressive retainer s around portions (e.g. external ends of the external portions 4b, 5b) of the first and second cable portions. The compressive retainer 6 exerts a compressive force on the portions of the first 4 and second 5 cable portions retained therein. The compressive retainer 6 extends along the axial direction of the bone transport device 1 .

[0131] In the examples of Figs 21 A-21 E, the compressive retainer 6 is a swage sleeve. That is, the external ends of the external portions 4b, 5b of the first 4 and second 5 cable portions are attached to one another by swaging. Specifically, the external ends are attached together via the swage sleeve 6 sleeved around the external ends. The external ends are fed through the swage sleeve 6 in opposite directions. The swage sleeve 6 is swaged and / or crimped using an appropriate tool to connect / fixedly attach the external portions 4b, 5b of the first 4 and second 6 cable portions together. The swage sleeve 6 is an oval swage sleeve. However, the swage sleeve 6 can have a different shape, and may be e.g. an hourglass swage sleeve. As discussed above, the swage sleeve 6 can allow the first 4 and second 5 cable portions to slide relative to each other within the swage sleeve upon application of a tensile force equal to or exceeding the predetermined tensile force, either while remaining connected, or while sliding out of the swage sleeve 6 completely to break the connection.

[0132] Next, a first variant of the bone connector 60 is discussed with reference to Figs 15 to 20. The bone connector 60 comprises a first cable receptacle 61a configured to at least partially receive the first cable portion 4, and a second cable receptacle 61 b configured to at least partially receive the second cable portion 5. The cable receptacles 61a, 61 b are configured to at least partially receive external ends of the external portions 4b, 5b of the first 4 and second 5 cable portions.

[0133] With reference to Figs 15-17, the cable receptacles 61a, 61 b are insertable into the bone piece 70. This can be achieved by drilling holes in the bone piece 70 using a suitable tool such as the jig 100 shown in Fig. 18. The cable receptacles 61 a, 61 b can be then inserted into the drilled holes within the bone piece 70.

[0134] As shown in Figs 15-17 for example, each cable receptacle 61a, 61 b is angled relative to the axial direction. The external ends of the first cable portion 4 and the second cable portion 5 are attached together via clamping and / or crimping over and between the cable receptacles 61 a, 61 b. In other examples, the external portions of the first and second cable portions may be attached to each other by tying their respective external ends together in a knot, e.g. over the pair of cable receptacles 61 a, 61 b. A second variant of the bone connector 60 is discussed with reference to Figs 11 and 12. Only the differences relative to the first variant are discussed below to avoid unnecessary repetition. In this variant, the bone connector 60 comprises a single cable receptacle 61 configured to receive external ends of both the first 4 and the second 5 cable portions. In addition to at least partially receiving the first 4 and second 5 cable portions, the cable receptacle 61 is further configured to retain the first cable portion 4 and the second cable portion 5. In use, the cable receptacle 61 extends perpendicularly to the axial direction.

[0135] The cable receptacle 61 is provided with a plug 62 insertable therein. The plug allows the external ends of the first 4 and second 5 cable portions to be clamped between an internal surface of the cable receptacle 61 and an external surface of the plug 62. The cable receptacle 61 comprises an internal threaded surface. The plug 62 comprises a threaded external surface configured to engage with the threaded internal surface of the cable receptacle 61 . Specifically, the plug 62 in this example is a grub screw. Thus, the external ends of the first 4 and second 5 cable portions are fixedly attached inside the cable receptacle 61 by screwing the grub screw 62 inside the cable receptacle 61 so as to clamp the external ends therein.

[0136] The bone transport device 1 further comprises a cable retainer 66 insertable into the cable receptacle 61 such that in use the cable retainer 66 is interposed between portions of the first 4 and second 5 cable portions received within the respective cable receptacle 61 and the plug 62 inserted therein. The cable retainer 66 comprises a pair of projections each engageable with a respective groove formed in the internal surface of the cable receptacle 61 . The cable retainer 61 can thus help retain the first 4 and second 5 cable portions in place within the cable receptacle 61 by pressing thereon. The cable retainer 61 can also space the cable portions from the plug 62. Conveniently, this prevents the plug 62 from directly exerting torque on the cable portions 4, 5 while the plug 62 is being screwed into the cable receptacle 61 , thereby reducing a risk of cable damage.

[0137] A third variant of the bone connector 60 is discussed with reference to Figs 21A-21 E. As in the second variant, the bone connector 60 comprises a single cable receptacle 61 configured to receive external ends of both 4 the first and the second 5 cable portions. In use, the cable receptacle 61 extends perpendicularly to the axial direction.

[0138] The bone connector 60 further comprises a holder 63 for supporting the external ends of the external portions 4b, 5b of the first 4 and second 5 cable portions. The holder 63 opens to the cable receptacle 61 such that the external ends can be fed to the holder 63 through the cable receptacle 61 . The holder 63 defines a channel 65 for receiving the external ends of the first 4 and second 5 cable portions. The channel is an axially extending, open channel (i.e. such that the channel supports the external ends from underneath and laterally, but does not fully enclose the external ends). The holder further comprises a recess transecting the channel 65 so as to expose an inner portion of the channel in use supporting the external ends. The recess extends perpendicularly to the channel. The recess provides access to the external ends of the first 4 and second 5 cable portion. The recess transects the channel 65 such that the holder 63 comprises four prongs 64 to support the external ends. The prongs 64 extend along the longitudinal axis of the bone connector 60 (e.g. the longitudinal axis of the cable receptacle 61). In use, the prongs 64 extend perpendicularly to the axial direction of the bone transport device 1 , and away from the cable receptacle 61. As discussed above, in the example of Figs 21A-21 E, the external ends of the external portions 4b, 5b of the first 4 and second 5 cable portions are connected to one another via a swage sleeve 6. The holder 63 supports (e.g. retains) the swage sleeve 6 in place.

[0139] As discussed with reference to Fig. 9 above, the slider 20 can be rotationally fixed relative to the tubular housing 10. That is, the slider 20 may be prevented from rotating around the elongated shaft 2. This is also shown in Fig. 23A where the tubular housing 10 comprises a lug 7 on an internal surface of the tubular housing 10. In the example of Fig. 23C, the internal surface of the tubular housing 10 is instead provided with a groove 8 for receiving a lug (not shown). The lug 7 can be provided on a radially outer surface of the slider 20.

[0140] In addition to, or instead of rotationally fixing the slider 20 relative to the tubular housing 10 via a lug 7 and a cooperating groove 8, the slider 20 can be rotationally fixed relative to the tubular housing 10 by providing the slider 20 such that it has a substantially oval transverse cross section with a maximum major diameter that is greater than the minimum diameter of the transverse cross section of the tubular housing 10. The transverse cross section is in a plane perpendicular to the shaft bore 22 of the slider 20. This is illustrated in Figs 14A, 14C, and 14D. In this example, the substantially oval transverse cross section is elliptical. The substantially oval transverse cross section of the slider 20 enables abutment between the radially outer surface of the slider 20 and a portion of the inner surface of the tubular housing 10 to prevent the slider 20 from rotating around the axial direction. The tubular housing 10 may have a circular transverse cross section (as shown in Fig. 22), or a substantially oval transverse cross section (as shown in Fig. 23B).

[0141] With reference to Fig. 14A, the shaft bore 22 can be radially offset from the slider’s longitudinal axis. This also helps rotationally fix the slider 20 relative to the tubular housing 10. In the example of Fig. 23A, the shaft bore 22 is spaced from the longitudinal axis of the slider 20 passing through the centre 25 of the oval cross section along the major diameter of the oval cross section.

[0142] The tubular housing 10 may have an external diameter of 10mm to 14mm inclusive, such as 10mm to 12mm inclusive or 12mm to 14mm inclusive. The tubular housing 10 may have an internal diameter of around 6mm. When the tubular housing 10 has an oval transverse cross-section, the tubular housing 10 may have a major diameter of 10mm to 14mm inclusive, such as 10mm to 12mm inclusive or 12mm to 14mm inclusive.

[0143] The slider 20 may have a diameter of around 5.5mm. When the slider 20 has a substantially oval transverse cross section, the major diameter of the slider 20 may be around 5.5mm.

[0144] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0145] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0146] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0147] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.

Claims

Claims:1 . A bone transport device for transporting a bone piece, the bone transport device comprising: an elongated shaft; a tubular housing enclosing the elongated shaft; a slider slidably mounted on the elongated shaft within the housing; an actuator configured to axially slide the slider along a slide portion of the elongated shaft; a first cable portion fixedly connectable to a bone connector external to the tubular housing, the first cable portion further being fixedly connected to the slider within the tubular housing; wherein the first cable portion is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the elongated shaft; the bone transport device being characterised in that the slide portion is circumscribed by a solid portion of the tubular housing and the first cable portion passes through a first aperture in a tubular wall of the tubular housing.

2. The bone transport device of claim 1 wherein the first cable portion loops through the first aperture and comprises an internal portion extending substantially axially from the slider to the first aperture and an external portion extending proximal the solid portion of the housing.

3. The bone transport device of claim 2 wherein the solid portion of the tubular housing comprises a first channel on a first external surface thereof for receiving the external portion of the first cable portion.

4. The bone transport device of claim 2 or 3 further comprising a first pulley wherein the first cable portion loops around the first pulley.

5. The bone transport device of any one of the preceding claims further comprising: a second cable portion fixedly connectable to the bone connector external to the tubular housing, the second cable portion further being fixedly connected to the slider within the tubular housing; wherein the second cable portion is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the elongated shaft; and wherein the second cable portion passes through a second aperture in the tubular wall of the tubular housing.

6. The bone transport device of claim 5 wherein the second cable portion loops through the second aperture and comprises an internal portion extending substantially axially from the slider to the second aperture and an external portion extending proximal the solid portion of the tubular housing.

7. The bone transport device of claim 6 further comprising a second pulley wherein the second cable portion loops around the second pulley.

8. The bone transport device of any one of claims 5 to 7 wherein the first aperture and the second aperture are axially spaced from one another by the solid portion of the tubular housing.

9. The bone transport device of claim 8 wherein the first cable portion is integral with or connected to the second cable portion.

10. The bone transport device of claim 9, wherein: the first cable portion is connected to the second cable portion at or inside the bone connector; andthe connection between the first cable portion and the second cable portion is configured to become at least partially released upon application of a predetermined tensile force.11 . The bone transport device of claim 9 or 10 wherein the predetermined tensile force is less than a tensile force associated with a tensile strength of the first cable portion and / or the second cable portion.

12. The bone transport device of any one of claims 9 to 11 , wherein the first cable portion is connected to the second cable portion via a compressive retainer.

13. The bone transport device of any one of the preceding claims wherein the slider comprises a cable bore for receiving the first and / or second cable portion, and a recess in a radially outer surface of the slider, the recess exposing the cable bore.

14. The bone transport device of any one of claims 9-11 wherein the slider comprises a cable bore for receiving the first and second cable portion, and a recess in a radially outer surface of the slider, the recess exposing the cable bore, wherein the first and second cable portions are connected within the recess.

15. The bone transport device of any one of claims 5 to 7 wherein the second aperture is diametrically opposed to the first aperture.

16. The bone transport device of claim 15 wherein the solid portion of the tubular housing comprises a second channel on a second external surface thereof for receiving the external portion of the second cable portion, the second external surface being diametrically opposed to the first external surface.

17. The bone transport device of any one of the preceding claims wherein the slider is rotationally fixed relative to the tubular housing.

18. A bone transport device for transporting a bone piece, the bone transport device comprising: an elongated shaft; a tubular housing enclosing the elongated shaft, the tubular housing comprising a first aperture in a tubular wall thereof; a slider slidably mounted on the elongated shaft within the housing; an actuator configured to axially slide the slider along a slide portion of the elongated shaft; a first cable portion fixedly connectable to a bone connector external to the tubular housing, the first cable portion being fixedly connected to the slider within the tubular housing; wherein the first cable portion passes through the first aperture and is configured to transmit a sliding force to the bone connector upon movement of the slider along the slide portion of the shaft; the bone transport device being characterised in that the slider is rotationally fixed relative to the tubular housing.

19. The bone transport device of claim 17 or 18 wherein a radially outer surface of the slider is configured for abutment and / or engagement with a portion of the inner surface of the tubular housing.

20. The bone transport device of any one of claims 17 to 19 wherein the slider has a substantially oval transverse cross section with a maximum major diameter that is greater than the minimum diameter of the transverse cross section of the tubular housing.21 . The bone transport device according to any one of claims 17 to 20 wherein the slider comprises a fixing element which rotationally fixes the slider relative to the tubular housing.

22. The bone transport device of claim 21 , wherein the fixing element is a lug and the bone transport device further comprises a cooperating groove, the lug being on one of the inner surface of the tubular housing and the radially outer surface of the slider, and the groove being on the other of the inner surface of the tubular housing and the radially outer surface of the slider.

23. The bone transport device of any one of claims 17 to 22 wherein the slider comprises a shaft bore and the elongate shaft is slidably received within the shaft bore, the shaft bore being radially offset from the slider’s longitudinal axis.

24. The bone transport device of any preceding claim further comprising the bone connector wherein the bone connector comprises at least one cable receptacle configured to at least partially receive the first cable portion and / or the second cable portion, the at least one cable receptacle being insertable into the bone piece.

25. A method of transporting a bone piece using the bone transport device of any preceding claim, the bone transport method comprising: connecting a first axial end of the bone transport device to a first bone portion; connecting a second axial end of the bone transport device to a second bone portion; performing corticotomy on the first bone portion to obtain the bone piece; fixedly connecting the bone connector to the bone piece; and axially sliding the slider along the slide portion of the elongated shaft to transport the bone piece.

Images