Patent Description:
Intraosseous access devices often require training to ensure correct placement of the access device. Users must coordinate the opposing actions of pulling proximally on a trigger, while applying sufficient distal driving force to penetrate the bone. Too little distal driving force results in osteonecrosis, where the needle tip rotates against the bone causing friction burns, instead of cutting into the bone as intended. Too much distal driving force can result in "back walling" where a needle penetrates a far wall of the bone. Further complications can arise when accessing bones of different sizes and density depending on the age and health of the patient. Moreover, IO access devices are often used in emergency situations where delays can be critical and fully trained users may not always be available. <CIT> relates to an apparatus and method for penetrating the bone marrow.

Embodiments disclosed herein are directed to push activated intraosseous (IO) access devices, and methods thereof. Push activated IO devices provide an intuitive operation with a unidirectional activation and drive force application. Further the device is both activated and deactivated automatically to prevent premature activation, guide a correct amount of distal driving force, and prevent "backwalling. " The device includes various indicators to further guide a user, who may have little or no training, in placing the device correctly. IO access devices disclosed herein further include replaceable battery packs, which may be either rechargeable or non-rechargeable, to ensure a full charge is available when the device is used, as well as providing a multi-use device that requires less storage space.

Disclosed herein is an intraosseous access device including, a housing, a trigger, and a drive train assembly, a portion of the drive train assembly slidably engaged with the housing, and configured to transition between a distal position, and a proximal position that actuates the trigger.

In some embodiments, the portion of the drive train assembly slidably engaged with the housing includes one of an electric motor, a gear assembly, a coupling structure, or an access assembly. The trigger is configured to connect a power supply with the drive train assembly when the trigger is actuated. The power supply is a battery pack disposed within the housing and configured to be removable and replaceable therefrom and wherein the battery pack is rechargeable or non-rechargeable. In some embodiments, the intraosseous access device further includes one of a force transducer, a variable speed sensor, a battery charge indicator, a timed stop sensor, or a trigger lock. The variable speed transducer is configured to modify a speed of the electric motor according to the amount of distal driving force applied to the intraosseous access device. The timed stop sensor is configured to stop the electric motor after a predetermined amount of time has elapsed. The trigger lock is transitionable between a locked position and an unlocked position, the trigger lock inhibiting the portion of the drive train assembly from transitioning to the proximal position when in the locked position.

In some embodiments, the intraosseous access device further includes a biasing member configured to bias the portion of the drive train assembly towards the distal position. A first force required to deform the biasing member and transition the portion of the drive train assembly from the distal position to the proximal position is greater than a second force required for a needle of an access assembly to penetrate a skin surface and less than a third force required for the needle to penetrate a bone cortex. In some embodiments, the intraosseous access device further includes a tensioning nut configured to adjust a tension of the biasing member. In some embodiments, the intraosseous access device further includes a force indicator configured to indicate an amount of force exerted on the biasing member. The force indicator includes one of a mechanical slider, a rotational dial, a series of graduated markings, or a series of LED lights.

Also disclosed is a method of placing an intraosseous access assembly including, providing an intraosseous access device having a driver, a drive train assembly, a portion of the drive train assembly transitionable between a first position and a second position, and an access assembly coupled to the drive train and including a needle, providing a first force to urge the access device distally until a tip of the needle penetrates a skin surface and contacts a bone cortex, providing a second force to urge the access device distally and transition the portion of the drive train assembly from a first position to a second position, rotating the access assembly, and drilling the needle through a bone cortex.

In some embodiments, the drive train includes one of a power source, an electronic control board, an electric motor, a gear assembly, or a coupling interface. The power source further includes a replaceable rechargeable or non-rechargeable battery pack. The drive train includes one of a drive spring, a drive spindle, a locking flange, or a coupling interface. In some embodiments, the method further includes an activation biasing member configured to bias the portion of the drive train assembly towards the first position, and wherein a force required to deform the activation biasing member is greater than the first force and less than second force. In some embodiments, the method further includes a tensioning nut configured to adjust a tension of the activation biasing member. In some embodiments, the method further includes a time out sensor configured to cease rotating the access assembly after a predetermined amount of time has elapsed.

Also disclosed is an access device including a driver housing, a drive spindle configured to rotate axially within the driver housing and configured to transition between a locked position and an unlocked position, a drive spring configured to rotate the drive spindle, and an access assembly coupled to the drive spindle.

In some embodiments, the access device further includes an activation biasing member configured bias the drive spindle to the locked position. A first force required to deform the activation biasing member and transition the drive spindle from the distal position to the proximal position is greater than a second force required for a needle of the access assembly to penetrate a skin surface and less than a third force required for the needle to penetrate a bone cortex. The activation biasing member is a compression spring and the first force is between <NUM> N (<NUM> lbs) and <NUM> N (<NUM> lbs) of force. In some embodiments, the access device further includes a tensioning nut threadably engaged with the driver housing, and configured to modify an amount of force required to deform the activation biasing member. The drive spindle further includes a locking flange configured to engage the driver housing and inhibit axial rotation when the drive spindle is in the locked position. The locking flange engages the driver housing with one of a plurality of ratchet teeth, a lug and detent, a frangible bridge, or a locking lever. The drive spring includes one of a torsion spring or a flat spring.

It is appreciated that these drawings depict only typical embodiments and are therefore not to be considered limiting of the scope of the invention.

With respect to "proximal," a "proximal portion" or a "proximal end portion" of, for example, a needle disclosed herein includes a portion of the needle intended to be near a clinician when the needle is used on a patient. Likewise, a "proximal length" of, for example, the needle includes a length of the needle intended to be near the clinician when the needle is used on the patient. A "proximal end" of, for example, the needle includes an end of the needle intended to be near the clinician when the needle is used on the patient. The proximal portion, the proximal end portion, or the proximal length of the needle can include the proximal end of the needle; however, the proximal portion, the proximal end portion, or the proximal length of the needle need not include the proximal end of the needle. That is, unless context suggests otherwise, the proximal portion, the proximal end portion, or the proximal length of the needle is not a terminal portion or terminal length of the needle.

With respect to "distal," a "distal portion" or a "distal end portion" of, for example, a needle disclosed herein includes a portion of the needle intended to be near or in a patient when the needle is used on the patient. Likewise, a "distal length" of, for example, the needle includes a length of the needle intended to be near or in the patient when the needle is used on the patient. A "distal end" of, for example, the needle includes an end of the needle intended to be near or in the patient when the needle is used on the patient. The distal portion, the distal end portion, or the distal length of the needle can include the distal end of the needle; however, the distal portion, the distal end portion, or the distal length of the needle need not include the distal end of the needle. That is, unless context suggests otherwise, the distal portion, the distal end portion, or the distal length of the needle is not a terminal portion or terminal length of the needle.

As shown in <FIG>, and to assist in the description of embodiments described herein, a longitudinal axis extends substantially parallel to an axial length of a needle <NUM> extending from the driver <NUM>. A lateral axis extends normal to the longitudinal axis, and a transverse axis extends normal to both the longitudinal and lateral axes.

As used herein, the term "spring" is considered to include any type of spring or biasing member that may store potential mechanical energy. Exemplary biasing members can include compression springs, extension springs, torsion springs, constant force springs, flat spring, flexible members, rubber rings, rubber band, leaf spring, V-spring, cantilever spring, volute spring, Belleville spring, gas spring, gravity-propelled biasing members, combinations thereof and the like, and are considered to fall within the scope of the present disclosure.

The present disclosure relates generally to intraosseous (IO) access devices, systems, and methods thereof. <FIG> shows an exploded view of an exemplary intraosseous access system ("system") <NUM>, with some components thereof shown in elevation and another shown in perspective. In an embodiment, the intraosseous access system <NUM> can be used to penetrate skin and underlying hard bone ("bone cortex") for intraosseous access, such as, for example to access the marrow of the bone and/or a vasculature of the patient via a pathway through an interior of the bone ("medullary cavity").

In an embodiment, the system <NUM> includes a driver <NUM> and an access assembly <NUM>. The driver <NUM> can be used to rotate the access assembly <NUM> and "drill" a needle <NUM> into the bone of a patient. In embodiments, the driver <NUM> can be automated or manual. As shown, the driver <NUM> is an automated driver <NUM>. For example, the automated driver <NUM> can be a drill that achieves high rotational speeds. In an embodiment, the intraosseous access system <NUM> can further include an obturator assembly <NUM>, a shield <NUM>, and a needle assembly <NUM>, which may be referred to, collectively, as the access assembly <NUM>. The needle assembly <NUM> can include an access needle ("needle") <NUM> supported by a needle hub <NUM>, as described in more detail herein. In an embodiment, the obturator assembly <NUM> includes an obturator <NUM>. However, in some embodiments, the obturator <NUM> may be replaced with a different elongated medical instrument. As used herein, the term "elongated medical instrument" is a broad term used in its ordinary sense that includes, for example, such devices as needles, cannulas, trocars, obturators, stylets, and the like. Accordingly, the obturator assembly <NUM> may be referred to more generally as an elongated medical instrument assembly. In like manner, the obturator <NUM> may be referred to more generally as an elongated medical instrument.

In an embodiment, the obturator assembly <NUM> includes a coupling hub <NUM> that is attached to the obturator <NUM> in any suitable manner (e.g., one or more adhesives or overmolding). The coupling hub <NUM> can be configured to interface with the driver <NUM>, as further discussed below. The coupling hub <NUM> may alternatively be referred to as an obturator hub <NUM> or, more generally, as an elongated instrument hub <NUM>. In an embodiment, the shield <NUM> is configured to couple with the obturator <NUM> to prevent accidental needle stick injuries when the obturator is removed after placement of the needle <NUM>.

In an embodiment, the needle assembly <NUM> includes a needle <NUM>. However, in some embodiments, the needle <NUM> may be replaced with a different instrument, such as, for example, a cannula, a tube, or a sheath, and/or may be referred to by a different name, such as one or more of the foregoing examples. Accordingly, the needle assembly <NUM> may be referred to more generally as a cannula assembly or as a tube assembly. In like manner, the needle <NUM> may be referred to more generally as a cannula.

In an embodiment, the needle assembly <NUM> includes a needle hub <NUM> that is attached to the needle <NUM> in any suitable manner. The needle hub <NUM> can be configured to couple with the obturator hub <NUM> and may thereby be coupled with the driver <NUM>, as further discussed below. The needle hub <NUM> may alternatively be referred to as a cannula hub <NUM>. In an embodiment, a cap <NUM> may be provided to cover at least a distal portion of the needle <NUM> and the obturator <NUM> prior to use of the access assembly <NUM>. For example, in an embodiment, a proximal end of the cap <NUM> can be coupled to the obturator hub <NUM>.

With continued reference to <FIG>, the driver <NUM> may take any suitable form. The driver <NUM> may include a handle <NUM> that may be gripped by a single hand of a user. In an embodiment, the driver <NUM> further includes a coupling interface <NUM>, which is formed as a socket <NUM> that defines a cavity <NUM>. The coupling interface <NUM> can be configured to couple with the obturator hub <NUM>. In an embodiment, the socket <NUM> includes sidewalls that substantially define a hexagonal cavity into which a hexagonal protrusion of the obturator hub <NUM> can be received. Other suitable connection interfaces are also contemplated.

The driver <NUM> can include an energy source <NUM> of any suitable variety that is configured to energize the rotational movement of the coupling interface <NUM>. For example, in some embodiments, the energy source <NUM> may comprise one or more batteries that provide electrical power for the driver <NUM>. In some embodiments, the energy source <NUM> can comprise one or more springs (e.g., a coiled spring, flat spring, or the like) or other biasing member that may store potential mechanical energy that may be released upon actuation of the driver <NUM>.

The energy source <NUM> may be coupled with the coupling interface <NUM> in any suitable manner. For example, in an embodiment, the driver <NUM> includes an electrical, mechanical, or electromechanical coupling <NUM> to a gear assembly <NUM>. In some embodiments, the coupling <NUM> may include an electrical motor that generates mechanical movement from electrical energy provided by an electrical energy source <NUM>. In other embodiments, the coupling <NUM> may include a mechanical linkage to the gear assembly <NUM>. The driver <NUM> can include a mechanical coupling of any suitable variety to couple the gear assembly <NUM> with the coupling interface <NUM>. In other embodiments, the gear assembly <NUM> may be omitted.

Further details and embodiments of the intraosseous access system <NUM> can be found in <CIT>, <CIT>, <CIT>, and <CIT>.

<FIG> shows an embodiment of an intraosseous access device <NUM>, including a driver <NUM> that includes a replaceable battery pack energy source ("battery pack") <NUM>. In an embodiment the battery pack <NUM> is removable and replaceable with similar battery packs. In an embodiment, the battery pack <NUM> can either be rechargeable or non-rechargeable. Advantageously, this allows a user of the system <NUM> to ensure there is sufficient power when the system is deployed in a placement event. Further, during a placement event, should the power be depleted from the first battery pack, a user can replace the first battery pack with a second, fully charged battery pack and continue the access procedure without having to wait for the first battery pack to be charged. As discussed herein, intraosseous access devices are often used in emergency situations and are therefore kept in storage for extended periods of time before being rapidly deployed in a placement event. The replaceable battery pack <NUM> mitigates a user's concerns about there being sufficient charge during a placement event.

In an embodiment, the driver <NUM> includes a battery charge indicator <NUM>. In an embodiment, the battery charge indicator <NUM> is disposed on the battery pack <NUM>. The battery charge indicator <NUM> can include one or more LED lights, icons, or the like, that can turn on or off, change color, or combinations thereof, to indicate a level of charge of the battery pack <NUM>. In an embodiment, the system <NUM> includes a charge indicator button <NUM> that a user can actuate to activate the battery charge indicator <NUM> and determine a charge level for the battery pack <NUM>. Advantageously, the driver <NUM> and one or more replacement battery packs <NUM> can provide sufficient power for multiple uses while requiring less storage space compared with multiple, single-use, devices. Further, the overall costs are reduced by requiring only a replacement battery pack rather than requiring multiple, single-use access systems.

As shown in <FIG>, in an embodiment, the driver <NUM> includes a pressure activated trigger <NUM>. The trigger <NUM> can be activated by an axial pressure on the access assembly <NUM>. In an embodiment, a longitudinal pressure can depress the access assembly <NUM> in a proximal direction and activate the trigger <NUM>, which activates the motor <NUM> and causes the access assembly <NUM> to rotate.

As used herein the battery pack <NUM> and any associated electronic control boards 115A, motor <NUM>, associated gear assemblies <NUM>, coupling structures <NUM>, access assembly <NUM>, or combinations thereof, can be collectively termed a drive train assembly ("drive train") <NUM>. In an embodiment, the drive train <NUM> or a portion thereof, can be slidably engaged within a housing <NUM> of the driver <NUM>. For example, as shown in <FIG>, a portion of the drive train <NUM>, including the motor <NUM>, coupling structures <NUM>, and access assembly <NUM>, can be slidably engaged along a longitudinal axis between a first, distal position (<FIG>) and a second, proximal position (<FIG>).

It will be appreciated, however, that any combination of components of the drive train <NUM> can be slidably engaged with the housing <NUM> with the remaining components of the drive train <NUM> remaining stationary. For example, in an embodiment, the portion of the drive train <NUM> slidably engaged with the housing <NUM> can include only the access assembly <NUM> with the remaining components remaining stationary. In an embodiment, all components of the drive train <NUM> can be slidably engaged with the housing <NUM>. In an embodiment, a component of the drive train <NUM> can be further sub-divided with a first portion remaining stationary and second portion slidably engaged with the housing <NUM>. For example, the coupling structures <NUM> can be made of a first piece slidably engaged with a second piece. As such, the portion of the drive train <NUM> that is slidably engaged with the housing <NUM> can include the access assembly <NUM> and a second piece of the coupling structures <NUM>. These and other combinations of drive train assembly <NUM> are considered to fall within the scope of the present disclosure.

In an embodiment, a biasing member, for example an activation spring <NUM>, can bias the slidable drive train <NUM>, or portion thereof that is slidably engaged with the housing <NUM>, towards a distal position. In an embodiment, a biasing member (e.g. a spring) can be disposed between a first portion and a second portion of the driver train <NUM>, for example between the second piece of coupling structure <NUM> and the access assembly <NUM>, to bias a portion of the drive train <NUM> towards a distal position. These and similar combinations of slidable drive train <NUM> are considered to fall within the scope of the present disclosure.

In an embodiment, the activation spring <NUM> can be a compression spring disposed within the driver <NUM>, between the portion of the slidable drive train <NUM> and a distal end of the driver housing <NUM>. However, as discussed herein, it will be appreciated that various other forms of biasing members are also contemplated, including compliant rubber discs, flexible metal tabs, or similar structures configured to bias the drive train <NUM> towards a distal position. In an embodiment, the driver <NUM> further includes a tensioning nut <NUM>. In an embodiment, rotating the tensioning nut <NUM> can adjust the tension on the activation spring <NUM>, and can modify the amount of force required to compress the activation spring <NUM> and activate the device, as discussed in more detail herein.

In an embodiment, a force required to compress the activation spring <NUM> can be between <NUM> N (<NUM> lbs) and <NUM> N (<NUM> lbs), although greater or lesser forces are also contemplated. As shown in <FIG>, in an embodiment, a force required for the needle <NUM> to penetrate the skin tissues <NUM> can be less than a force required to compress activation spring <NUM>. As such the activation spring <NUM> can maintain the drive train <NUM> in a proximal position as the needle penetrates the skin tissues <NUM>. In an embodiment, a force required for the needle <NUM> to penetrate the bone cortex <NUM> can be greater than a force required to compress activation spring <NUM>. As such, when the needle tip <NUM> contacts the bone cortex <NUM>, a user can apply additional distal driving force to compress the activation spring <NUM> and transition the drive train <NUM> from the distal position (<FIG>) to the proximal position (<FIG>).

As shown in <FIG>, in the proximal position, the drive train <NUM> contacts the trigger <NUM>, which activates the motor <NUM> and rotates the access assembly <NUM>. The needle tip <NUM> then drills through the bone cortex <NUM> and accesses the medullary cavity <NUM>. The density of the tissue within the medullary cavity <NUM> is less than the density of the bone cortex <NUM>. As such, a force required for the needle <NUM> to penetrate the tissues of the medullary cavity <NUM> can be less than a force required to compress activation spring <NUM>. When the needle tip <NUM> enters the medullary cavity <NUM>, the force of the activation spring <NUM> transitions the drive train <NUM> back to the distal position. This disengages the trigger <NUM>, stops the motor <NUM> and automatically stops any rotation of the access assembly <NUM>.

In an embodiment, the driver <NUM> can further include a tensioning nut <NUM>, which is configured to rotate and move a spring support <NUM> along a longitudinal axis. This can adjust the amount force required to transition the drive train <NUM> from the distal position to the proximal position. As such, the tension of the activation spring <NUM> can be adjusted depending on various factors including age of the patient, health condition of the patient, the density of the bone cortex <NUM>, the density of the tissue within the medullary cavity <NUM>, combinations thereof, or the like.

In an exemplary method of use, an intraosseous access system <NUM> is provided including a driver <NUM>, an access assembly <NUM>, and a replaceable battery <NUM>, as described herein. In an embodiment, the access assembly <NUM> and/or the replaceable battery <NUM> are provided pre-loaded in the driver <NUM>. In an embodiment the access assembly <NUM> and/or the replaceable battery <NUM> are provided separately and the user can load the access assembly <NUM> and/or the replaceable battery <NUM> to the driver <NUM> prior to use. The user can check a charge level of the battery <NUM> using battery level indicator <NUM>. If necessary the user can replace the battery <NUM> with a fully charged battery <NUM>. In an embodiment, the system <NUM> can further include a cap <NUM> to protect the needle <NUM> of the access assembly <NUM>.

The user can position a tip <NUM> of the needle <NUM> at the insertion site and apply a distal driving force to urge the driver <NUM> in a distal direction. As described herein, the activation spring <NUM> is configured to maintain the driver train <NUM> in a distal position as the needle <NUM> is urged through the skin surface tissues <NUM>. The distal tip <NUM> of the needle <NUM> then contacts the hard bone cortex <NUM> which inhibits further distal advancement. The user continues to urge the driver <NUM> distally with sufficient force to overcome the force of the activation spring <NUM>. This causes the drive train <NUM> to slide proximally, relative to the driver <NUM>, and activate the trigger <NUM>. The trigger <NUM> activates the motor <NUM> which causes the access assembly <NUM> to rotate and drill the needle <NUM> through the bone cortex <NUM>. When the needle tip <NUM> penetrates through the bone cortex <NUM> and into the medullary cavity <NUM>, the activation spring <NUM> can transition the drive train <NUM> back to the distal position since the force of the activation spring is greater than a force required to penetrate the needle <NUM> through tissues of the medullary cavity <NUM>. In the distal position, the trigger <NUM> is disengaged, which disengages the motor <NUM> and ceases rotation of the access assembly <NUM>.

Advantageously, the system <NUM> provides an intuitive function that only requires a single directional force to be applied to start the placement event, i.e. start drilling, compared with pulling a "pistol-style" trigger in a proximal direction while applying a driving force in a distal direction. Further, the activation spring <NUM> can be configured to deform and activate the device <NUM> automatically when the correct level of distal driving force is applied. A user can progressively increase the amount of distal driving force until the activation spring <NUM> compresses and activates the system <NUM>, guiding the user towards a correct level of distal driving force.

Further still, the activation spring <NUM> can be configured to deactivate the device <NUM> automatically either when the user removes the distal driving force or when the needle <NUM> accesses medullary cavity <NUM>. The automatic deactivation can indicate to a user of successful placement. This is of particular importance to prevent "back walling" which can lead to various complications. Further, the automatic deactivation of the device can act as a safety feature, deactivating the device if the device is removed from the insertion site. In an embodiment, the drive train <NUM> can also be configured to apply the correct torque and rotational speed for fast and effective access.

In an embodiment, the system <NUM> can be configured to modify the amount of torque and/or rotational speed based on the amount distal driving force applied. As such the system <NUM> can be configured to guide a user to deliver the correct balance of distal driving force, torque, and rotational speed for an intuitive, fast and efficient IO access placement. A user thereby requires little or no training to use the system <NUM>. This is of particular importance intraosseous access devices are often used within emergency situations where speed of placement is important, and users may not necessarily have had any prior training.

In an embodiment, the driver <NUM> can be configured in a variety of compact or ergonomic shapes. For example, user-actuated triggers, i.e. devices that are selective actuated by a user, can be limited to pistol-grip style configurations in order to position the trigger in an accessible position. Automatic, pressure-activated triggers are not reliant on such configurations and can allow for more compact or ergonomic configurations of the system <NUM>. For example, as shown in <FIG>, a cylindrical driver 101A is provided that defines a substantially tubular shape extending along a longitudinal axis. Such designs can provide more compact drivers <NUM> than pistol-grip style drivers leading to greater efficiencies in the storage and transport of the devices. These and other ergonomic or compact designs are also contemplated to fall within the scope of the present disclosure.

In an embodiment, the driver <NUM> includes a force sensor (not shown), in addition to the activation spring <NUM>, that is configured to automatically stop the driver <NUM> once the bone cortex <NUM> has been penetrated. In an embodiment the force sensor is a pressure transducer that detects an axial force applied to the needle tip <NUM>. The force sensor can be configured to detect a presence or absence of axial force applied to the needle tip <NUM>. The system <NUM> can then determine when the needle tip <NUM> has penetrated the bone cortex <NUM> and entered the medullary space <NUM>, and can deactivate the motor <NUM> to prevent further drilling. Advantageously, the force sensor provides an additional safeguard to prevent back walling. Further, the force sensor can allow a user to selectively activate or deactivate the driver <NUM> during the placement event, by applying or removing a distal driving force.

In an embodiment, the driver <NUM> includes a variable speed sensor configured to adjust the speed of the motor <NUM> proportionally to the amount of distal driving force that is applied to the driver <NUM>. For example, the variable speed sensor is configured to detect the amount of force applied to the driver <NUM>, or amount of deformation applied to the activation spring <NUM>, or the like. The variable speed sensor then increases the speed of the motor proportionally to the amount of force applied or deformation detected. Advantageously, the variable speed sensor balances the correct rotational speed with the amount of distal driving force applied to provide efficient intraosseous placement. This prevents osteonecrosis or back walling, as discussed herein. Advantageously, on activation, the driver <NUM> can be configured to "ramp up" the motor speed to prevent a sudden start to the activation, which can cause the needle tip <NUM> to travel away from the selected insertion site leading to misplacement of the access device. Further, the sudden start to the activation can startle the user and also lead to misplacement of the access device.

In an embodiment, the driver <NUM> includes a timed stop sensor. The timed stop sensor provides an automatic stop after a set amount of time has elapsed since the device was activated. In an embodiment, the timed stop sensor deactivates the motor between <NUM> seconds and <NUM> seconds after the motor has been activated. Advantageously, the timed stop sensor provides a safeguard against back walling, by deactivating the motor after a predetermined amount of time has elapsed e.g. <NUM>-<NUM> seconds, or an amount of time required to drill through the bone cortex <NUM>. Further, the timed stop sensor also prevents the battery from being depleted accidentally, for example, during an accidental activation event during storage or transport.

In an embodiment, the driver <NUM> includes a trigger lock. The trigger lock can include a slide switch, electronic switch, or the like, configured to prevent premature activation of the trigger <NUM>. For example, the trigger lock can be a slide switch configured to inhibit the drive train <NUM> from transitioning from the distal position to the activated, proximal position. During use, the user can release the trigger lock switch prior to starting the access event. Advantageously, the trigger lock can prevent accidental activation of the driver <NUM> prior to use, e.g. during transport or storage.

As shown in <FIG>, in an embodiment, the driver <NUM> includes a distal driving force indicator <NUM>. The force indicator <NUM> can include a series of LED lights, a mechanical slider, a rotational dial, combinations thereof, or the like, and include graduated markings <NUM>. The force indicator <NUM> can include a mechanical or electronic transducer that detects an amount of distal driving force applied to the driver <NUM> and indicate the amount force, relative to a correct amount of force, which needs to be applied. For example, <FIG> shows close up detail of a force indicator <NUM> that can be disposed on an outer surface of the driver <NUM>. In an embodiment, the drive train <NUM> can be linked with a slider <NUM> disposed on an outer surface of the driver <NUM>. As the user applies a distal driving force, the drive train <NUM> can slide proximally relative to the driver <NUM>, as described herein. The slider <NUM>, coupled with the drive train <NUM> can also slide proximally relative to the driver housing <NUM>. A series of graduated markings <NUM> disposed on the driver housing <NUM>, together with the slider <NUM>, can indicate to a user if sufficient distal driving force is being applied, or too much force, or too little force. Advantageously, the force indicator <NUM> can further guide a user as to the correct operation of the system <NUM>, even if the user has had little or no training. In an embodiment, the force indicator <NUM> includes a rotational dial that rotates about a series of graduated markings to indicate an amount of force applied. In an embodiment, the force indicator <NUM> includes one or more LED lights that turn on and off, and/or change color, to indicate an amount of force applied. These and similar configurations of mechanical or electronic force indicators are considered to fall within the scope of the present disclosure.

As shown in <FIG>, in an embodiment, an intraosseous access system <NUM> generally includes a spring driven energy source <NUM>, and a force actuation spring <NUM>. The access system <NUM>, includes a driver <NUM> having a driver housing <NUM> defining a substantially cylindrical shape, although other shaped housings <NUM> are also contemplated. The access system <NUM> further includes a spring driven energy source <NUM> and a drive spindle <NUM>, disposed within the driver housing <NUM>. The drive spindle <NUM> is configured to rotate about a longitudinal axis of the driver <NUM>. The drive spindle <NUM> is further configured to slide along a longitudinal axis between a distal, locked position, and a proximal unlocked position, as described in more detail herein. The drive spindle <NUM> further includes a locking flange <NUM> that is configured to engage the driver housing <NUM> when the drive spindle <NUM> is in the distal, locked position, and disengage the driver housing <NUM> when the driver spindle <NUM> is in the proximal unlocked position, as described in more detail herein.

The spring driven energy source ("drive spring") <NUM> can include a torsion spring configured to store rotational potential energy. However, it will be appreciated that other biasing members are also contemplated. The drive spring <NUM> can be coupled with both the driver housing <NUM> and the drive spindle <NUM> in a tensioned state. As such, when the locking flange <NUM> disengages the driver housing <NUM>, allowing the drive spindle <NUM> to rotate freely, the drive spring <NUM> causes the drive spindle <NUM> to rotate about the longitudinal axis.

In an embodiment, the driver <NUM> further includes a coupling interface <NUM> disposed at a distal end of the drive spindle <NUM> and configured to engage an access assembly <NUM>, as described herein. Rotation of the drive spindle <NUM> can cause the access assembly <NUM> to rotate and causes the needle <NUM> to drill through the bone cortex <NUM>, and access the medullary cavity <NUM>, as described herein. As used herein, the drive spring <NUM>, drive spindle <NUM>, locking flange <NUM>, coupling interface <NUM>, or combinations thereof can be collectively termed a drive train assembly.

In an embodiment, the driver housing <NUM> includes a tensioning nut <NUM> threadably engaged with the driver housing <NUM>. Rotating the tensioning nut <NUM> about the longitudinal axis, can cause the nut <NUM> to move along the longitudinal axis relative to the driver housing <NUM>. In an embodiment, the driver <NUM> includes a force activation spring <NUM>, disposed annularly about the drive spindle <NUM>, between the tensioning nut <NUM> and the coupling interface <NUM>. In an embodiment, the activation spring <NUM> is a compression spring, configured to resist a compressive force before deforming. In an embodiment, the compressive force required to deform the spring is between <NUM>-<NUM> N (<NUM>-<NUM> lbs) of force, although greater or lesser forces are also contemplated. In an embodiment, rotating the tensioning nut <NUM> can modify the amount of compressive force required to deform the activation spring <NUM>. In an embodiment, the activation spring <NUM> is configured to bias the drive spindle <NUM> towards the distal locked position. When a proximal force is applied to the needle tip <NUM>, sufficient to compress the activation spring <NUM>, the drive spindle <NUM> can move to the proximal unlocked position, activating the device.

In an embodiment, the coupling interface <NUM> is threadably engaged with drive spindle <NUM>, such that rotating the coupling interface <NUM> about the longitudinal axis causes the coupling interface <NUM> to move longitudinally relative to the drive spindle <NUM>. As such, rotating the coupling interface <NUM> can modify the tension of the activation spring <NUM> disposed between the coupling interface <NUM> and the driver housing <NUM> or tensioning nut <NUM>.

In an embodiment, the locking flange <NUM> can include one or more locking features configured to allow the locking flange <NUM> to selectively engage or disengage the driver body <NUM>. <FIG> show some exemplary embodiments of locking features. In an embodiment the flange <NUM> can include a first, flange locking feature, e.g. flange ratchet teeth <NUM>, configured to selectively engage a second, driver locking feature, e.g. housing ratchet teeth <NUM>, to selectively inhibit relative movement therebetween.

As shown in <FIG>, in an embodiment, the locking flange <NUM> includes a plurality of ratchet teeth <NUM> that are configured to engage a plurality of housing ratchet teeth <NUM> disposed on the housing <NUM>, tensioning nut <NUM>, or combinations thereof. The flange ratchet teeth <NUM> and housing ratchet teeth <NUM> are configured to engage to inhibit rotational movement of the drive spindle <NUM> about the longitudinal axis in a first direction, e.g. a clockwise direction, and configured to allow stepwise rotation in a second, opposite, direction, e.g. anti-clockwise direction. Advantageously, this allows the drive spring <NUM> to be tensioned by rotating the drive spindle <NUM> in the second direction. The system <NUM> maintains the tension by the engagement of the flange ratchet teeth <NUM> and housing ratchet teeth <NUM> to prevent rotation in the first direction. In an embodiment, when a proximal force is applied to the needle tip <NUM>, which is sufficient to overcome the compression force of the activation spring <NUM>, the spindle <NUM> and locking flange <NUM> move proximally and disengage the flange ratchet teeth <NUM> from the housing ratchet teeth <NUM> to allow free rotation of the spindle <NUM>. The drive spring <NUM> then causes the drive spindle <NUM> to rotate as described herein.

As shown in <FIG>, in an embodiment, the drive spindle <NUM> includes one or more lugs <NUM> that engage one or more detents <NUM> disposed within the housing <NUM>, tension nut <NUM>, or combinations thereof. As shown in <FIG>, the lugs <NUM> engage the detents <NUM> and prevent rotational movement of the drive spindle <NUM>. In an embodiment, when a proximal force is applied to the needle tip <NUM>, which is sufficient to overcome the compression force of the activation spring <NUM>, the spindle <NUM> and locking flange <NUM> move proximally and disengage lugs <NUM> from the detents <NUM> to allow free rotation of the spindle <NUM>. The drive spring <NUM> then causes the drive spindle <NUM> to rotate as described herein.

As shown in <FIG>, in an embodiment, the locking flange <NUM> includes a frangible bridge <NUM> that is formed between the locking flange <NUM> and the housing <NUM>, tension nut <NUM>, or combinations thereof. The frangible bridge <NUM> can include a tear line, e.g. a score line, laser cut line, perforation, or the like, that is configured to break when a predetermined force is applied, allowing the locking flange <NUM> to separate from the housing body <NUM> or tension nut <NUM>. For example, when a proximal force is applied to the needle tip <NUM>, which is sufficient to overcome the force required for the breach line to separate, the frangible bridge <NUM> detaches from the housing <NUM>/tension nut <NUM>, allowing the spindle <NUM> and locking flange <NUM> move proximally and to allow free rotation of the spindle <NUM>. The drive spring <NUM> then causes the drive spindle <NUM> to rotate as described herein. In an embodiment, the frangible bridge <NUM> can be used in place of the activation spring <NUM> to prevent proximal movement until sufficient proximal force is applied. In an embodiment, the frangible bridge <NUM> can be used in addition to the activation spring <NUM> to prevent proximal movement until sufficient proximal force is applied.

As shown in <FIG>, in an embodiment, the driver <NUM> includes a locking lever <NUM>, configured to engage the locking flange <NUM>, drive spindle <NUM>, or combinations thereof to prevent the drive spindle <NUM> from rotating. In an embodiment, an outer surface of the locking flange <NUM> includes one or more locking teeth. The locking lever <NUM> engages the locking teeth and prevents the drive spindle <NUM> from rotating. In an embodiment, when a proximal force is applied to the needle tip <NUM>, which is sufficient to overcome the compression force of the activation spring <NUM>, the spindle <NUM> moves proximally. As shown in <FIG>, a portion of the locking lever <NUM> is actuated by the proximal movement of the drive spindle <NUM> and causes the locking lever <NUM> to pivot and disengage from the locking flange <NUM> to allow free rotation of the spindle <NUM>. The drive spring <NUM> then causes the drive spindle <NUM> to rotate as described herein.

In an exemplary method of use a spring driven intraosseous access system <NUM> is provided, as described herein, including a coiled drive spring <NUM> and an activation spring <NUM>. A user urges the driver <NUM> distally until a needle tip <NUM> penetrate a skin surface <NUM>. To note, the resistance of the needle <NUM> penetrating the skin tissues <NUM> is less than a force required to deform the activation spring <NUM>. As such the drive spindle <NUM> and access assembly <NUM> remains a distal, locked position. The needle tip <NUM> then contacts the bone cortex <NUM>, a user can continue to urge the driver <NUM> distally with sufficient force to deform the activation spring <NUM> by pressing the access assembly <NUM> into the bone cortex <NUM>. The access assembly <NUM> and driver spindle <NUM> slides proximally relative to the driver housing <NUM>, compressing the activation spring <NUM> between the coupling interface <NUM> and the tensioning nut <NUM> portion of the driver housing <NUM>. The locking flange <NUM>, coupled to the driver spindle <NUM>, disengages from the driver housing <NUM> allowing the driver spindle <NUM> to rotate. The drive spring <NUM> causes the driver spindle <NUM> and access assembly <NUM> to rotate, drilling the needle <NUM> into the bone cortex <NUM> and accessing the medullary cavity.

As shown in <FIG>, in an embodiment, an intraosseous access system <NUM> is provided including a flat drive spring <NUM>. The access system <NUM>, includes a driver <NUM> having a driver body <NUM>, with a flat drive spring <NUM>, a drive spindle <NUM>, and a collector spindle <NUM>, disposed therein.

In a tensioned state, the drive spring <NUM> is wrapped about the drive spindle <NUM>. As the drive spring transitions between a tensioned state and an untensioned state, the flat spring unwinds from the drive spindle <NUM>, causing the drive spindle to rotate, and is wound on to the collector spindle <NUM>. <FIG> shows a plan view of the drive spindle <NUM>, the collector spindle <NUM> and the flat drive spring <NUM> extending therebetween, including the associated direction of rotation for each of the drive spindle <NUM> and the collector spindle321. Advantageously, the flat drive spring provides a more constant torque and more constant rotational speed as the spring transitions between a tensioned and an untensioned state.

In an embodiment, the drive spindle <NUM> and the collector spindle <NUM> remain in a longitudinally fixed position, relative to the drive body <NUM>. In an embodiment, a coupling interface <NUM> is slidably engaged with the drive spindle <NUM> along a longitudinal axis. The coupling interface <NUM> is also coupled with the drive spindle <NUM> such that any rotational movement of the drive spindle <NUM> causes the coupling interface <NUM> and access assembly <NUM> to rotate.

In an embodiment, the driver <NUM> includes an activation spring <NUM>, disposed within the drive spindle <NUM> and is biased to maintain the coupling interface <NUM> is a distal position. When a force is applied to a needle tip <NUM> in a proximal direction, which is sufficient to overcome the force of the activation spring <NUM>, the activation spring <NUM> can deform and allow the coupling interface <NUM> to slide longitudinally. The coupling interface can further include a locking flange, as described herein. As the coupling interface <NUM> transitions from a distal position to a proximal position, the locking flange can disengage allowing the coupling interface <NUM> and drive spindle <NUM> to rotate. The coupling interface <NUM> and locking flange can include various ratchet teeth, lugs and detents, frangible bridges, locking levers, combinations thereof, or the like, as described herein, to selectabley inhibit rotation of the coupling interface <NUM> and drive spindle <NUM> assembly until activated.

In an embodiment, the driver <NUM> further includes a tensioning nut <NUM>, which is threadably engaged with the driver housing <NUM>. As such, rotating the tensioning nut <NUM> about the longitudinal axis can modify the tension of the activation spring <NUM> which can modify the amount of force required to move the access assembly <NUM> longitudinally and trigger the device <NUM>.

In an exemplary method of use a spring driven intraosseous access system <NUM> is provided, as described herein, including a flat drive spring <NUM> and an activation spring <NUM>. A user urges the driver <NUM> distally until a needle tip <NUM> penetrates a skin surface <NUM>. To note, the resistance of the needle <NUM> penetrating the skin tissues <NUM> is less than a force required to deform the activation spring <NUM>. As such the activation spring <NUM> maintains the coupling interface <NUM> and access assembly <NUM> in a distal, locked position. The needle tip <NUM> then contacts the bone cortex <NUM> where the resistance to needle penetration is greatly increased. A user can continue to urge the driver <NUM> distally with sufficient force to deform the activation spring <NUM> by pressing the access assembly <NUM> into the bone cortex <NUM>. The access assembly <NUM> and coupling interface <NUM> slides proximally relative to the driver housing <NUM>, compressing the activation spring <NUM> between the coupling interface <NUM> and the tensioning nut <NUM>. The locking feature, which is configured to inhibit rotation of the coupling interface <NUM>, disengages from the driver housing <NUM> allowing the coupling interface <NUM> and access assembly <NUM> to rotate, drilling the needle <NUM> into the bone cortex <NUM> and accessing the medullary cavity <NUM>.

Advantageously, the drive springs disclosed herein, e.g. drive spring <NUM>, <NUM>, can maintain the stored energy of over an extended period of time without depleting. Further, these drive springs include an inherent time stop feature to prevent backwalling, as described herein. i.e. The drive spring <NUM> can be configured to provide sufficient rotations of the access assembly to drill through the bone cortex before reaching an untensioned state and ceasing further drilling. In an embodiment, the drive springs are configured to provide between <NUM>-<NUM> rotations to provide sufficient drilling to penetrate the bone cortex and access the medullary cavity without backwalling. It will be appreciated, however, that the drive springs can also be configured to provide fewer or greater numbers of rotations.

In an embodiment, as shown in <FIG>, the drive train can include a drive spindle <NUM>, drive spring <NUM>, collector spindle <NUM>, and access assembly <NUM>. The drive train can be slidably engaged relative to the housing <NUM> along a longitudinal axis, as described herein. The activation spring <NUM> can be disposed between the drive train, e.g. the drive spindle <NUM>, and the housing <NUM> and can bias the drive train towards a distal position (<FIG>). In an embodiment, one of the drive spindle <NUM> or the collector spindle <NUM> can include a locking engagement feature, as described herein, configured to selectively inhibit rotation of the drive spindle <NUM>. For example, as shown in <FIG>, the drive spindle can include a first set of ratchet teeth <NUM> disposed on the drive spindle <NUM> configured to engage a second set of ratchet teeth <NUM> disposed on the housing <NUM> in the distal position. As shown in <FIG> an axial force applied to the access assembly <NUM> can compress the activation spring <NUM>, allowing the drive train to transition to the proximal position. This in turn can allow the first set of ratchet teeth <NUM> to disengage the second set of ratchet teeth <NUM> and allow the drive spindle <NUM> to rotate, as described herein.

In an embodiment, as shown in <FIG>, the drive train can include the drive spindle <NUM>, drive spring <NUM>, collector spindle <NUM>, and access assembly <NUM>, and can further include a gear mechanism <NUM>. The gear mechanism <NUM> can either be "geared up" or "geared down" to modify one of the speed or torque of the access assembly <NUM> relative to the rotation speed of the drive spindle <NUM>. The gear mechanism <NUM> can include spur gears, planetary gears, helical gears, bevel gears, miter gears, worm gears, screw gears, combinations thereof, or the like.

In an embodiment, the gears within the gear mechanism <NUM> can slide along the longitudinal axis relative to each other. As such, when an axial force is applied to the access assembly <NUM>, the access assembly <NUM> and gear(s) 317B coupled thereto can slide longitudinally from the distal position to the proximal position. The drive spindle <NUM> and gear(s) 317A coupled thereto and remain stationary relative to the longitudinal position. The movement of the access assembly <NUM> and gear(s) 317B can disengage a locking feature, e.g. ratchet teeth <NUM>, <NUM> and can allow the gear mechanism <NUM>, drive spindle <NUM> and access assembly <NUM> to rotate, as described herein. The system <NUM> can further include an activation spring <NUM> configured to bias the access assembly <NUM> and gear(s) 317B towards the distal, locked position. In an embodiment the locking feature can be configured to engage the drive gear 317A coupled with the drive spindle <NUM>.

In an embodiment, a gear ratio between the drive spindle <NUM> and the access assembly <NUM> can be greater than <NUM>. Further the locking feature can be configured to engage the driven gear 317B coupled to the access assembly <NUM>. Advantageously, the force required by the locking feature to engage and inhibit movement of the driven gear 317B can be less than the force required to engage and inhibit movement of the drive gear 317A where the drive ratio is greater than <NUM>.

While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claim 1:
An intraosseous access device (<NUM>), comprising:
a housing (<NUM>);
a trigger (<NUM>); and
a drive train assembly (<NUM>), a portion of the drive train assembly (<NUM>) slidably engaged with the housing (<NUM>), and configured to transition between a distal position, and a proximal position that actuates the trigger (<NUM>),
wherein the trigger (<NUM>) is configured to connect a power supply with the drive train assembly (<NUM>) when the trigger (<NUM>) is actuated.