Patent ID: 12220128

Many aspects of the disclosure can be better understood with reference to these figures in combination with the description of specific embodiments presented herein. The elements and features shown in the figures are not necessarily to scale, emphasis being placed upon clearly illustrating the principles of example embodiments of the disclosure. Moreover, certain dimensions may be exaggerated to help visually convey such principles. In the figures, common reference numerals often designate like or corresponding, but not necessarily identical, elements throughout the several views.

DETAILED DESCRIPTION

Detailed descriptions of one or more embodiments are provided herein. It is to be understood, however, that the present technology may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to practice a variety of embodiments in any appropriate manner.

Those of ordinary skill in the art having benefit of this disclosure will be able, without undue experimentation, to combine compatible elements and features that are described in detail at various places in this written description, which includes text and illustrations. That is, the figures and specification are organized to facilitate practicing numerous combinations, such as by combining elements of one illustrated or textually-described embodiment with other elements of one or more other illustrated or textually-described embodiments.

Whenever the phrases “for example”, “such as”, “including”, and the like are used herein, the phrase “and without limitation” is understood to follow unless explicitly stated otherwise. Similarly, “an example,” “exemplary,” and the like are understood to be non-limiting.

The terms “comprising” and “including” and “having” and “involving” (and similarly “comprises”, “includes”, “has,” and “involves”) and the like are used interchangeably and have the same meaning. Specifically, each of the terms is defined consistent with the common United States patent law definition of “comprising” and is therefore interpreted to be an open term meaning “at least the following” and is also interpreted not to exclude additional features, limitations, aspects, etc. Thus, for example, “a process involving steps a, b, and c” means that the process includes at least steps a, b, and c. As another example, when a first device comprises a second device, the first device may include the second device or the second device may include the first device.

Whenever the terms “a” or “an” are used, “one or more” is understood, unless such interpretation is nonsensical in context.

The term “couple,” as may be used herein, generally refers to joining, connecting, or associating something with something else.

As one of ordinary skill in the art will appreciate, the term “operably coupled,” as may be used herein, encompasses direct coupling and indirect coupling via another, intervening component, element, circuit, or module; moreover, a first component may be operably coupled to a second component when the first component comprises the second component.

As one of ordinary skill in the art will appreciate, the term “substantially” or “approximately,” as may be used herein, provides an industry-accepted tolerance to its corresponding term. Such an industry-accepted tolerance ranges from less than one percent to twenty percent and corresponds to, but is not limited to, component values, process variations, and manufacturing tolerance.

As further disclosed below, some embodiments of a system for tissue regeneration can comprise one or more of a drive, a retractor, a regulator, a controller, a coupler, a reel, a line, and an energy storage device, not necessarily as distinct elements. Further, these terms may have overlapping scope. For example, a spring-loaded reel can comprise a retractor, a regulator, a controller, and an energy storage device. Similarly, a method or process for tissue regeneration can comprise one or more of driving, retracting, regulating, controlling, coupling, reeling, and storing energy, not necessarily as distinct actions. Further, these terms may have overlapping scope.

Turning now to the figures, the technology will be further described with reference to example illustrated embodiments.FIGS.1A-1Fillustrate an example embodiment of a system150for regeneration in an example application of nerve regeneration. The system150may be employed to regenerate severed or damaged nerves in a human or other animal or may be used in other contexts wherein tension may be advantageous to improve regeneration of damaged tissue other than nerve tissue, such as severed ligaments, tendons or muscles.FIGS.1A-IF will now be discussed in detail.

FIG.1Ais an illustration of an example treatment site100in which the example system150may be employed. In the illustrated example, an injury130resulted in a transection of a nerve111, creating a distal nerve end105and a proximal nerve end110separated by a nerve gap135, which is disposed between the proximal and distal nerve ends105,110. As discussed above, in various embodiments, the nerve injury130may have resulted from trauma, combat injury, cancer, congenital condition, lesion, bacterial or fungal infection, or some other malady or issue. In some embodiments, the distal and proximal nerve ends105,110have been surgically produced, for example by surgical removal of a section of a nerve111that a medical practitioner has deemed to be nonviable.

As illustrated, the nerve111has a longitudinal axis140, which in the example embodiment ofFIG.1Aextends from the proximal nerve end110across the nerve gap135towards the distal nerve end105. The nerve111extends through soft tissue120in a nerve channel145. The nerve111extends along bone115with a proximal portion of the bone116corresponding to the proximal nerve end110and a distal portion of the bone117corresponding to the distal nerve end105.

FIG.1Bis an illustration of an example installation of the system150, as may be performed by a surgeon on a human patient, a nonhuman primate, zoo animal, pet, race horse, or another appropriate vertebrate or other animal. In the illustrated example ofFIG.1B, the system150comprises a distraction unit155with an associated line165and a pump system175with an associated tube180, which will be discussed in detail with reference to subsequent figures.

FIG.1Bparticularly illustrates an initial phase of installation, in which the distraction unit155has been anchored or fastened to the bone115with fasteners160. The fasteners160may comprise screws, staples, adhesives, cements, or other appropriate fastening means. In various embodiments, the line165may comprise monofilament, thread, or suture material for connecting the distraction unit155to the proximal nerve end110in order to generate tension along the distraction axis170, which extends alongside and approximately aligns with the longitudinal axis140of the nerve111. In some example embodiments, the line165comprises nylon or fluoropolymer material.

In one example embodiment, the line165comprises a segment of elastic material (or may be elastic along essentially its entire length), such as a tube or strand of medical-grade silicone elastomer. In one example embodiment, such an elastomeric composition can stretch in accordance with applied tension and may absorb or damp tension spikes associated with patient movement.

In one example embodiment (not illustrated) the surgeon sutures one end of an elastic line to the proximal nerve end110, stretches the elastic line, and then sutures the other end to a distal portion of bone117or to the distal nerve end105. The stretched elastic line can thus apply sustained distractive force to one or both nerve ends105,110to stimulate growth.

As further discussed below with reference to subsequent figures, in various example embodiments, the distraction unit155may comprise a constant force spring or a servo-motor mechanism. A servo-motor mechanism may be wirelessly connected to a host controller for regulation or modification of torque settings, such as to tune or maintain an amount of tension placed on the proximal nerve end110.

The example pump system175comprises a reservoir (not illustrated) for one or more pharmaceutical agents or other treatment modalities, which the pump system175pumps through the tube180to the proximal nerve end110. In some embodiments, the pump system175comprises two or more reservoirs for storing two or more agents along with a capability for drawing the agents selectively from each reservoir, for example to create an on-demand blend that may be adjusted during treatment.

In some example embodiments, the pump system175, or a second pump (not illustrated), may connect to a second tube (not illustrated) for delivery of pharmaceutical agents or other treatment modalities to the distal nerve end105. In various embodiments, the pump system170and associated tube180can deliver anesthetics, nutrients, growth factors, pharmaceuticals recognized as encouraging nerve growth, oxygenated fluid, gaseous oxygen, or combinations of such materials or other substances that promote nerve regeneration. In some example embodiments, the pump system175and associated tube180deliver one or more materials described in the above Background section that are recognized as supporting nerve regeneration.

It is to be understood by one having ordinary skill in the art that the device described herein may be used for veterinary applications and for research as well as for human patients in trauma and other medical conditions as discussed above. In some example embodiments, the pump system175may comprise a micro infusion pump commercially available from Primetech Corporation of Tokyo, Japan under the registered trade name of “IPRECIO,” such as the products bearing the model numbers “SMP-310” or “SMP-200.” Pump system175may comprise a microcontroller or microprocessor and further be capable of wireless communication with a host controller for modification of dosage and flow rate. In some example embodiments, the pump system175comprises an automatic feedback loop that regulates delivery of one or more pharmaceuticals according to detected nerve growth or other sensed physiological parameters. For example, as the proximal nerve end110lengthens (or when a threshold length is achieved), the controller may automatically adjust pharmaceutical delivery parameters, such as ceasing, reducing, or increasing delivery rate or switching from one pharmaceutical agent to another or changing relative concentrations of pharmaceutical agents in a blended composition.

As illustrated, the pump system175may be disposed in or adjacent to the injury site100or above the injury site100. In the illustrated embodiment, the pump system170is implanted; in some other embodiments, the pump system175is disposed external to the patient, with the tube180extending into the treatment site100. In various embodiments, the pump system175may be placed subcutaneously or in-line with the system150or the distraction unit155. Subcutaneous placement of the pump system175can facilitate convenient replacement or refilling of the pump reservoir. In some embodiments, the tube180may comprise an elastomeric material (for example medical-grade silicone) to reduce any drag associated with retraction of proximal nerve end110.

In some example embodiments, the tube180further comprises an optical waveguide for delivering visible, infrared, or ultraviolet light to stimulate growth or otherwise provide benefit. For example, an optical fiber can be embedded in a wall of the tube180or may extend alongside the tube180. A laser light source or light emitting diode coupled to the optical fiber may be included in pump system175, for example.

The tube180may further comprise electrical lines (embedded or running alongside) and electrodes for delivering electrical stimulation to the proximal nerve end110to stimulate growth, maintain activity in the nerve111, or otherwise provide benefit. The electrodes may additionally or alternatively be connected to the distal nerve end105. An associated electrical source may be included in pump175. Such electrical lines may further provide electricity for a transducer (not illustrated) positioned adjacent the proximal nerve end110(or the distal nerve end I05). The transducer can convert the electricity into a form of energy having a potential to encourage nerve growth and/or suppress pain, for example comprising a piezoelectric element that vibrates or emits waves.

FIGS.1C and1Dare further illustrations of the example installation of the system150, particularly illustrating a second phase of installation in which the line165is attached to the proximal nerve end110. As illustrated byFIG.1C, the line165and a traveling nerve channel stent195have been extended from the distraction unit155, which is anchored to bone115as discussed above. A surgeon may pull the line165and traveling nerve channel stent195out of the distraction unit155and use a hemostat or clip to relieve retractive force during the installation procedure, for example.

As illustrated inFIG.1C, the traveling nerve channel stent195helps keep the nerve channel145open so that the proximal nerve end can grow without undue occlusion or interference. In some example embodiments, the traveling nerve channel stent195can comprise a structure of sufficient mechanical integrity to maintain a nerve channel145. The traveling nerve channel stent195can comprise medical-grade fluoropolymer, stainless steel, titanium, or a mesh or wire frame, for example. In some example embodiments, the traveling nerve channel stent195can comprise a membrane, a porous member, or a structure that is permeable to gas, liquids, or substances that support nerve regeneration. The traveling nerve channel stent195can comprise one or more biopolymers, a mesh, a woven fabric, or a non-woven fabric, to mention some representative embodiments. In some example embodiments, the traveling nerve channel stent195can comprise one or more pharmaceutical agents that are eluted or otherwise released to the nerve111or otherwise to the treatment site100. In some example embodiments, the traveling nerve channel stent195can comprise a commercially available nerve guidance conduit or artificial nerve conduit.

As discussed below, in some embodiments, the traveling nerve channel stent195travels with nerve growth to keep the nerve channel145open. In some example embodiments, the traveling nerve channel stent195may be viewed as a pilot. In some example embodiments, the traveling nerve channel stent195is replaced with a nerve guidance conduit or artificial nerve conduit or a stent that is permanently implanted in a static position (so that it does not travel with nerve growth). In such an embodiment, the line165can extend through the bore197(first labeled atFIGS.1E and1F) of the conduit or stent and apply force to the proximal nerve end110that effectively pulls the nerve end110into or towards the bore197.

As illustrated, the tube180feeds through a hole196in the traveling nerve channel stent195and extends along with the line165. Thus tube180passes through hole196such that the delivery end of the tube180is disposed proximate to proximal nerve end110.

FIG.1Dillustrates the installation focused on the proximal nerve end110of the transected nerve111. With the line165, the tube180, and traveling nerve channel stent195extended, the surgeon can attach the line165to the distal nerve end110as illustrated in the detail view ofFIG.1D. Line165is sutured to the proximal nerve end110with sutures185, which attach to a knot168in the line165. Each suture185is disposed in the myelin sheath112of axon114as shown inFIG.1D. The surgeon may create an array of suture attachments that collectively circumscribe the myelin sheath112, for example on intervals of 60 degrees so that six sutures attach the line165to the myelin sheath112. The number of suture attachments may be selected in practice according to the size or location of the nerve111, the level of retractive force prescribed, the age of the patient, and/or other factors deemed relevant.

A crimp-on imaging marker169is attached to the line165as a location aid. In an example embodiment, the crimp-on imaging marker169comprises a bead of metal or other material that is conducive to location using ultrasound, x-rays, or other imaging modality. The imaging marker169supports assessing nerve growth using non-invasive imaging, since the marker169moves as the proximal nerve end110undergoes distraction neurogenesis as discussed below.

FIGS.1E and1Fare illustrations of the system150after installation at the injury site I00at the start of treatment and at the completion of treatment respectively.FIGS.1E and1Frespectively illustrate the traveling nerve channel stent195extracted from and inserted in an aperture156in an extension157of the distraction unit155.

As discussed above, in the illustrated embodiment, the system150is attached to bone115, and the distraction unit155is attached to the proximal nerve end110via the line165with sutures185. The traveling nerve channel stent195is depicted transparent inFIGS.1E and1Fto visually convey how the line165can extend through the bore197of the traveling nerve channel stent195. The transparent depiction further illustrates how a crimp-on retention bead198is captured to provide independent proximal motion of the traveling nerve channel stent195during installation and to cause joint motion in the distal direction after installation. The cross-sectional view ofFIG.5(discussed below) illustrates further details about how travelling nerve channel stent195is attached to line165with crimp-on retention bead198in the illustrated example.

In operation, as the proximal nerve end110is pulled towards the distraction unit155, it is guided by the travelling nerve channel stent195which can keep the nerve channel145open during the period of treatment. Example embodiments and operations of the distraction unit155will be further described below with reference to subsequent figures.

Turning now toFIG.2, this figure illustrates a flowchart disclosing an example process or method200of action of the system150. In a representative embodiment, a care provider (for example a surgeon, physician, veterinarian or other appropriate medical practitioner) determines that treatment of an injury to a peripheral nerve in a limb (or appropriate nerve other appropriate body part) would be improved by regeneration of a severed nerve and elects to initiate the process200.

Certain steps or actions of the process200, as well as of the other processes and methods disclosed or taught herein, may naturally need to precede other steps or actions to achieve desirable functionality. However, the disclosure is not limited to the order of the steps or actions described if reordering or resequencing does not adversely alter functionality to the extent of rendering the technology inoperable or nonsensical. Accordingly, it is recognized that some steps or actions may be performed before or after others or in parallel with others without departing from the scope and spirit of the disclosure.

At block205of process200, a surgeon installs the system150. A care provider (for example comprising the surgeon, another profession, or a team) can determine an appropriate torque to effectively regenerate the nerve111and may select hardware or tension settings according to patient size and body part. For example, a particular size of traveling nerve channel stent195can be selected according to nerve diameter and physiology. In some example embodiments, tension in a range of approximately a tenth of an ounce of force (approximately 0.03 N) to approximately ten ounces of force (approximately 3 N) may be selected. Larger nerves or larger subjects may generally warrant larger force applications. In one example embodiment, applied tension is in a range of approximately one-half ounce (approximately 0.1 N) to approximately three ounces (approximately 0.8 N) for a peripheral nerve in an animal weighing approximately 150 pounds (approximately 68 kg).

At block210, the distraction unit155applies the specified torque value to a reel or servo-motor mechanism within the distraction unit155. Subsequent figures, discussed below, illustrate example embodiments of these elements.

At block215, the reel or servo-motor mechanism translates the torque to linear force or tension on the line165. Subsequent figures, discussed below, illustrate example embodiments of these elements.

At block220, the line165applies the linear force to the proximal nerve end110.

At block225, the pump system175delivers medication to the proximal nerve end110. At block230, a shock absorber may be included to smooth the applied force by damping spikes associated with movement of tissue near the nerve111, for example as the patient moves or is moved.FIG.9, discussed below, illustrates an example embodiment of a shock absorber.

At block235, the applied force stimulates nerve growth.

At block240, the reel or servo-motor mechanism maintains the prescribed force as the nerve111lengthens. The applied force can accordingly be regulated. The applied force can alternatively be regulated by following a predetermined trajectory or path, for example decreasing or increasing in a predetermined or selected manner as the nerve111lengthens.

At decision block245an inquiry is made as to whether the treatment has produced sufficient nerve regeneration. If the decision is negative, then process200loops back to block210and blocks210-240iterate until sufficient regeneration has been achieved. In some example embodiments, the decision is automatic, such as by software stored in nonvolatile memory of the system150and executed by a controller of the system150. In some example embodiments, once the system150has determined that nerve growth is sufficient, the system150emits a wireless indicator signal for reception by a detector located outside the patient, thereby notifying of completion (or of intermediate progress).

In some example embodiments, the care provider determines when the treatment has resulted in sufficient nerve regeneration. In some example embodiments, the care provider uses non-invasive imaging to determine location of the imaging marker169which correlates to nerve growth.

At block250, once sufficient regeneration has occurred, the surgeon rejoins the distal and proximal nerve endings105,110.

Once the surgeon has joined the nerve ends105,100, process200ends at block260.

Referring now toFIGS.3A-D, these figures illustrate orthonormal views of the distraction unit155along with the traveling nerve channel stent155, both as example embodiments thereof. For viewing clarity, the drive mechanism and internal cavity of the distraction unit155are not depicted in these views, but rather are illustrated inFIG.6. A shoulder300(illustrated inFIG.5in detail) provides a mechanical stop that prevents the distraction unit155from retracting the traveling nerve channel stent195into the internal workings of the distraction unit155.

Referring now toFIG.4, this figure provides a view of an example embodiment of the travelling nerve channel stent195. A hole400provides passage for the line165into and through the bore197of the travelling nerve channel stent195. A tapered end405of the travelling nerve channel stent195seats against the shoulder300and further can provide a nose cone to facilitate moving through soft tissue with reduced drag. The tapered end405can further facilitate reception by the aperture156in the extension157of the distraction unit155.

Referring now toFIG.5, this figure is a detail view of the line165passing through hole400in the tapered end405of traveling nerve channel stent195. The tapered end405seats against shoulder300. A crimp-on retention bead198prevents the line165from being draw back into the distraction unit155beyond a pre-determined distance.

Referring now toFIG.6, this figure illustrates a cross sectional view of an example embodiment of the distraction unit155. In operation, the line165is retracted into the housing603of the distraction unit155, through shoulder300, by a drive system600that rotates a reel610. The reel610comprises a cylindrical winding surface612about which the line165winds as the drive system600rotates the reel610.

The reel610is disposed in a cavity605of the housing603, which can be formed of medical-grade stainless steel, titanium, or other biocompatible material suitable for implanting. As illustrated, the housing cavity605is sized to match the reel610, so that the reel610is located coaxially with respect to a housing post620and has clearance to rotate freely. For example, the housing cavity605can have a diameter that is oversized relative to the reel610, for example to provide a radial clearance in a range of 0.1 to 2.0 millimeters or another appropriate value as may be varied for different sizes, forces, applications, and construction materials.

In the illustrated example, the drive system600comprises a spring630that is coaxially disposed with respect to the reel610and the housing post620. As illustrated, the spring630is disposed in a coiled state a cavity615of the reel610. The spring630is held at one end by a spring retention slot625in the housing post620and at the other by a spring retention aperture635disposed within the reel610. In some embodiments, a rotary damper or other damper (not illustrated inFIG.6) may be included to smooth spikes in force associated with limb movement.

In various embodiments, the spring630may have more or fewer coils than illustrated. The number of coils can be selected according to whether or how much the force delivered is to be constant or is to vary over the length of travel, and/or further by the overall length of travel. In some embodiments, the retractive force varies linearly over the length of travel. In some embodiments, the retractive force varies less than 2, 5, 10, or 15 percent over the length of travel. In the illustrated embodiment, the spring630comprises a coiled strip of metal (such as spring-tempered stainless steel); in some other embodiments, the spring630comprises a length of spring wire that may be coiled. In an example alternative embodiment, a silicone elastomeric member supplies rotational force to the reel610.

In some example embodiments (without limitation), the spring630can comprise one or more of a constant force spring, a constant torque spring, a power spring, a spiral spring, a clock spring, a strip spring, or a wire spring, as such terms are typically applied in industry and as understood by those of skill in the art having benefit of the present disclosure. The preceding sentence is not intended to imply that the terms may have overlapping scope.

In some example embodiments, the drive system600can comprise a spring or spring drive commercially available from the Spiroflex division of KERN-LIEBERS Ltd. of Schramberg, Germany. In some example embodiments, the drive system600can comprise a spring or spring drive commercially available from Vulcan Spring of Telford, PA, USA under the trade identifier “CONFORCE” for constant force springs or the trade identifier “CONTORQUE” for constant torque springs. In some example embodiments, the drive system600can comprise a spring drive system commercially available from the West Coast Corporation of Ontario, California, USA, such as the drive system in the consumer product that the company markets as “MINI-BAK RETRACTABLE BADGE HOLDER, SKU 0055-005” which is available in a choice of two or four ounces of specified retraction force. In some example embodiments, the drive system600can comprise a spring or spring drive commercially available from the Hunter Spring division of AMETEK. Inc. in Horsham, PA, USA, such as the spring motor assemblies marketed under the trade identifier “NEG′ ATOR” and designated as part number ML-1448.

In some example embodiments, the spring drive system600comprises a servo-motor drive system, which will be further discussed below with reference toFIG.11.

Referring now toFIGS.7Aand B, these figures illustrate orthonormal views of an example embodiment of the reel610. In some example embodiments, the reel610is composed of stainless steel or an appropriate polymer such a fluoropolymer, nylon, or acetal resin. The diameter700of the cylindrical winding surface612correlates with the tension that a particular drive system600applies to the line165in the configuration illustrated atFIG.6. Increasing the diameter700decreases line tension, while decreasing the diameter700increases line tension. Accordingly, reel diameter700can be selected to achieve a selected line tension.

Referring now toFIG.8, this figure illustrates a perspective view of a spacer800for increasing the effective diameter700of the cylindrical winding surface612of the reel610. In application, the spacer800can be snapped onto or otherwise disposed on the reel610, over the cylindrical winding surface612. This provides a capability to vary the diameter700of the cylindrical winding surface612and thus applied force. As an alternative to the spacer800, the reel610can be partially filled with backing line to increase the diameter700. Another alternative for achieving different forces (as may be beneficial for different applications) is to swap out springs with different force characteristics or to increase force by using multiple springs at the same time.

Referring now toFIG.9, this figure is an illustration of a shock absorber900disposed on the line165as an example embodiment of a damper. The illustrated shock absorber900includes a dashpot905and a spring910for damping. The shock absorber900can relieve spikes in force associated with limb movement. In some example embodiments, the shock absorber900may positioned adjacent the proximal nerve end110or inside the traveling nerve channel stent195. In some embodiments, a damper (such as a shock absorber, dashpot, or rotary damper) is included in the mechanisms of the drive system600inside the housing603of the distraction unit155.

Turning now toFIGS.10Aand B, another example embodiment is illustrated and will now be discussed.FIGS.10A and10Bare illustrations of an example drive system1000, withFIG.10Aillustrating an overhead view andFIG.10Billustrating a side view. The drive system1000can be enclosed in a housing in accordance with the housing603illustrated inFIG.6. For example, the drive system1000can be enclosed in a housing having the outward geometry of the illustrated housing603with an interior space configured to accommodate the drive system1000. The drive system1000can be operated in accordance with the foregoing discussion. Accordingly, the drive system1000can provide retractive tension on the line165. Additionally, the drive system1000can comprise one or more shock absorbers900(seeFIG.9and accompanying discussion) or other appropriate damper.

As illustrated, the example drive system1000comprises two shafts1025,1030that are mounted to the housing603, for example via threads, press fit, weld, braze, epoxy, or other appropriate fastening means. The two shafts1025,1030can be formed of stainless steel or other appropriate material.

A spring drum1020is mounted to and rotates freely about the shaft1025, with a shaft head1026capturing the spring drum1020on the shaft1025. In some embodiments, the shaft head1026is countersunk in a recess in the spring drum1020, in which case the shaft head1026would be hidden in the view ofFIG.10A. Countersinking can provide a compact profile.

Another spring drum1015and a reel1010are mounted to and rotate freely in unison about the shaft1030, with a shaft head1031capturing them on the shaft1030. The shaft head1031can be countersunk in a recess in the reel1010as discussed in the immediately preceding paragraph. The spring drum1015and the reel1010can be formed out of a unitary piece of material (for example a piece of stainless steel) or otherwise connected to one another to provide unitary rotation.

In the illustrated embodiment, a constant force spring1005extends circumferentially around each of the spring drums1015,1020. That is, one end (hidden from view inFIGS.10A and10B) of the constant force spring1005wraps about the spring drum1020, and the opposite end1007of the constant force spring1005wraps about and is attached to the spring drum1015. While the spring end1007is illustrated in the view ofFIG.10A, in practice the end1007may be hidden from view by additional windings about the spring drum1015. For example, the length of the constant force spring1005may be selected according to desired travel distance, with a margin of at least one additional wrap to avoid over-extension issues.

In operation, the constant force spring1005seeks to transition to a low-energy state whereby the windings transfer from the spring drum1015to the spring drum1020. In other words, the constant force spring1005wants to release stored energy by unwinding from the spring drum1015and winding onto the spring drum1020. As illustrated by the representative arrows overlaid upon the view ofFIG.10B, the constant force spring1005thus applies rotational force or torque to the spring drum1015, which in turn applies rotational force or torque to the reel1010, which in turn applies linear pulling force to the line165, which in turn applies linear pulling force to the proximal nerve end110, which in turn stimulates nerve regeneration in accordance with the foregoing discussion of the preceding figures. As the proximal nerve end110regenerates and lengthens, the drive system1000rotates the reel1010to provide ongoing regulated tension.

Turning now toFIG.11, this figure illustrates a functional block diagram of an embodiment of a system1100for regenerating nerves that employs an electric motor1105for reel rotation in place of a spring (or alternatively for use with a spring). The electric motor1105is controlled by a controller1135. The electric motor1105delivers force to the line165, the force is modulated by a gearbox1110and is coupled by a coupler1115to a reel1120. One or more sensors1125gather feedback signals1127which convey force and/or position/displacement information (and/or other physiological information relevant to nerve regeneration) to the controller1135. These feedback signals1127are used by the nerve regeneration engine1150, which is stored in nonvolatile memory1145, and an associated processor1140to modulate the amount of torque generated by the motor1105so as to regulate and/or optimize the tension placed on the proximal nerve end110by the line165.

The nerve regeneration engine1150may comprise instructions for executing certain steps of a nerve regeneration process. For example, in some embodiments, the nerve regeneration engine1150comprises executable instructions for implementing the loop of blocks210,215,220,225,230,235,240, and245of process200as illustrated in flowchart form byFIG.2and discussed above. The processor1140can comprise a microprocessor, a microcontroller, or other appropriate computing system for executing such an embodiment of the nerve regeneration engine1150, for example.

As illustrated, power for the system1100is supplied by a power supply1155. In various embodiments, the power supply1155may comprise a battery capable of being recharged via inductive coupling through the skin of the patient. The sensors1125may comprise a strain gauge, a torque sensor, a force sensor, a displacement sensor or other appropriate sensors for gathering relevant feedback signals1127.

In one example embodiment, the sensor1125comprises a strain gauge that measures the amount of force on the line165(as applied to the proximal nerve end110). In operation, the controller1135compares the measured force to a threshold level. If the controller1135determines that the measured force is above the threshold level, then the controller1135leaves the electrical motor1105in an off state, whereby the measured force is maintained and unnecessary energy consumption is avoided. If, on the other hand, the controller1135determines that the measured force is below the threshold level, then the controller1135turns the electric motor1105on, and the electric motor1105responds with rotation.

The gearbox1110gears down the rotational motion of the electric motor1105and comprises a ratchet wheel and pawl that prevents unwanted backward rotation or other appropriate gearing arrangement or means. The gearbox1110drives rotation of the reel1120via the coupler1115, which in various embodiments can comprise a rotary damper, a spring, or any link, member, fastener or other means for transmitting force and motion between the gearbox1110and the reel1120(without limitation). The rotation of the reel1120increases force on the line165until the controller1135determines that the measured force meets the threshold level. Once the threshold level is met, the controller1135turns the electric motor1105off, and the ratchet wheel and pawl of the gearbox1110hold the rotational position of the reel1120. Once the nerve sufficiently lengthens, the measured force drops below the threshold level, and the controller1135again prompts the electrical motor to drive rotation of the reel1120until the force threshold is met. In this manner the system1110can maintain a target level of force applied to the proximal nerve end110while managing energy consumption.

In an example variation, the controller1135can utilize a deadband approach for regulating applied force. In this approach, the controller1135uses one force threshold for turning the motor on and another force threshold for turning the motor off The difference between the two thresholds can define a deadband range in which the target force lies.

Technology useful for regenerating tissue has been described. From the description, it will be appreciated that an embodiment of the disclosure overcomes limitations of the prior art. Those skilled in the art will appreciate that the technology is not limited to any specifically discussed application or implementation and that the embodiments described herein are illustrative and not restrictive. Furthermore, the particular features, structures, or characteristics that are set forth may be combined in any suitable manner in one or more embodiments based on this disclosure and ordinary skill. Those of ordinary skill having benefit of this disclosure can make, use, and practice a wide range of embodiments via combining the disclosed features and elements in many permutations without undue experimentation. This disclosure not only includes the illustrated and described embodiments, but also provides a rich and detailed roadmap for creating many additional embodiments using the various disclosed technologies, elements, features, and their equivalents. From the description of the example embodiments, equivalents of the elements shown herein will suggest themselves to those skilled in the art, and ways of constructing other embodiments will appear to practitioners of the art. Therefore, the scope of the technology is to be limited only by the appended claims.

Moreover, those skilled in the art will recognize, or be able to ascertain using their skill, the present teaching, and no more than routine experimentation, many equivalents to the specific embodiments described herein. Such equivalents are intended to be encompassed by the following claims.

All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference into the specification to the same extent as if each individual publication, patent or patent application was specifically indicated to be incorporated herein by reference.

Other embodiments are in the claims.