Method of treating nerve injuries

Abstract

The present disclosure relates to methods of treating nerve injuries. In particular, the present disclosure relates to methods of repairing severed peripheral nerves in a subject as well as reducing pain and increasing protective sensation.

Description

METHOD OF TREATING NERVE INJURIESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 618,213, filed January 5, 2024, which is incorporated herein by reference in its entirety.BACKGROUNDField

[0002] The present disclosure relates to methods of treating nerve injuries. In particular, the present disclosure relates to methods of repairing severed nerves in a subject as well as reducing pain and increasing protective sensation.Description of the Related Art

[0003] Peripheral nerve transections from trauma commonly occur in civilian and military populations and often result in prolonged or permanent significant loss of sensation and neuromuscular function. Recovery from peripheral nerve transection requires surviving proximal stumps to extend outgrowths (an innate action), limited to growth rates of approximately 1 mm / day, that often slowly, partially, and non-specifically reinnervate distal target tissues. The rate of regeneration may vary depending on location along the neuron in which proximal segments may see an increase of 2-3 mm / day while more distal segments may progress at a rate of 1-2 mm / day.

[0004] Reinnervation occurs over months-to-years post-operatively in large mammals such as humans. Severed distal axonal segments in mammals always degenerate within three days. Brushart, T. (2011) Nerve Repair. New York, NY: Oxford University Press, Inc.; Bittner et al., Regeneration Research 2015, 1406-1408; Spaeth et al, Journal of Neuroscience Research (2012, 1-12. Degeneration of the distal stump of the nerve results in denervation of target tissues that may severely and permanently atrophy before innate regeneration can occur.

[0005] Improving the rate and quality of mammalian axonal regeneration has been a major goal for neuroscientists and peripheral nerve repair surgeons, with repair strategies to date (e.g., nerve growth guides, nerve coaptation protection appliances, microsutures) relyingon guiding axonal outgrowth to increase reinnervation success. Such techniques sometimes improve recovery of sensation and function, but do not affect the rate of axonal outgrowth, improve the time course of recovery, nor prevent Wallerian degeneration of severed distal axons. Riley etal., JNeurosci Res.2Q 5, 572-583; Ghergherehchi etal., JNeurosci Res.2Q 6, 231-245; Kalbermatten et al., J Reconstru Microsurg, 2009 27-33; Kawasaki et al., J Hand SurgAm. 2000, 104-11.

[0006] Due to the direct costs of acute care, rehabilitation, loss to the workforce and long-term disability, the aggregate economic impact to the US healthcare system secondary to PNI has been estimated at >$150 billion. These staggering statistics coupled with the current lack of medical technologies to improve the speed and quality of recovery from PNI underscore the significance of the need for better therapeutic alternatives. Contemporary standard of care for transected PNI involves surgical reattachment of the proximal and distal stumps of the injured nerve using microsutures (“neurorrhaphy”). Unfortunately, neurorrhaphy does not address the underlying problem of obligatory degeneration of all distal axonal segments of the severed nerve. More importantly, no technology in clinical practice nor in development has been shown to increase the speed nor the quality of natural regeneration, which remains the only possible route to sustained recovery. Long-term clinical outcomes from PNIs include partial to near-complete loss of sensation and / or function manifesting in some degree of disability, which is many times permanent in nature. Accordingly, a need exists for methods that improve clinical outcomes for patients with PNIs.SUMMARY

[0007] In a first aspect of the present disclosure, provided herein is a method of repairing a severed nerve, the method comprising: applying at least 5 mL of hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the chamber, wherein the PEG solution is 50% PEG 3350 Da w / w in water; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with at least 10 mL of Lactated Ringers Solution.

[0008] In a second aspect of the present disclosure, provided herein is a method of repairing a severed nerve in a subject reporting a numeric pain rating of from 2 to 6 on a scale of 0 to 10, the method comprising: applying hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying a PEG solution to the severed nerve region within the chamber; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with a calcium-containing isotonic saline; wherein the subject exhibits a decrease of at least 0.5 numeric pain rating four weeks after nerve repair.

[0009] In a third aspect of the present disclosure, provided herein is a method of increasing protective sensation in a hand of a subject having a severed nerve from below the distal border of the brachial plexus to the fingertip, wherein the subject senses a Semmes- Weinstein Monofilament Test (SWMT) force using a SWMT filament of size greater than 6.65 g, the method comprising: applying hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying a PEG solution to the severed nerve region within the chamber; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with a calcium-containing isotonic saline; wherein the subject senses a SWMT force using a SWMT filament of size less than 4.56 g 12 weeks after nerve repair.

[0010] In a fourth aspect of the present disclosure, provided herein is a PEG solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of a hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within a nerve treatment device; applying no more than 2.5 mL of the PEG solution to the severed nerve region within the device; aspirating the PEG solution from the device; andremoving the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of a Lactated Ringers Solution.

[0011] In some embodiment of the fourth aspect, the hypotonic saline has a calcium concentration of less than 500 ppm. In some embodiments, the PEG solution is 50% PEG 3350 Da w / w in water.

[0012] In some embodiments of the fourth aspect, the PEG solution is administered in combination with the hypotonic saline solution and the Lactated Ringers solution.

[0013] In a fifth aspect of the present disclosure, provided herein is a hypotonic saline solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of the hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within nerve treatment device; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the device; aspirating the PEG solution from the device; and removing the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of a Lactated Ringers Solution.

[0014] In some embodiment of the fifth aspect, the hypotonic saline has a calcium concentration of less than 500 ppm. In some embodiments, the PEG solution is 50% PEG 3350 Da w / w in water.

[0015] In some embodiments of the fifth aspect, the hypotonic saline solution is administered in combination with the PEG solution and the Lactated Ringers solution.

[0016] In a sixth aspect of the present disclosure, provided herein is a Lactated Ringers solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of a hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within a nerve treatment device; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the device;aspirating the PEG solution from the device; and removing the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of the Lactated Ringers Solution

[0017] In some embodiment of the sixth aspect, the hypotonic saline has a calcium concentration of less than 500 ppm. In some embodiments, the PEG solution is 50% PEG 3350 Da w / w in water.

[0018] In some embodiment of the sixth aspect, the Lactated Ringers solution is administered in combination with the hypotonic saline solution and the PEG solution.

[0019] In a seventh aspect of the present disclosure, provided herein is a combination of a hypotonic saline solution, a PEG solution and a Lactated Ringers solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of the hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within nerve treatment device; applying no more than 2.5 mL of the PEG solution to the severed nerve region within the device; aspirating the PEG solution from the device; and removing the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of Lactated Ringers Solution.

[0020] In some embodiment of the seventh aspect, the Lactated Ringers solution is administered in combination with the hypotonic saline solution and the PEG solution.

[0021] In some embodiments described herein, the PEG solution, the hypotonic saline solution and the Lactated Ringers solution are administered in the following sequence: a) the hypotonic saline solution; b) the PEG solution; and c) the Lactated Ringers; wherein the order of the sequence is a), b) then c).

[0022] In some embodiments described herein, the treatment further comprises trimming the first and second severed ends of the nerve before applying the calcium-free hypotonic solution. In some embodiments, the hypotonic saline is calcium-free.

[0023] In some embodiments, the nerve is a peripheral nerve. In some embodiments, the nerve injury is a severed nerve. In some embodiments, the nerve is severed from below the distal border of the brachial plexus to the fingertip.

[0024] In some embodiments, the subject reports a numeric pain rating of from 2 to 6 on a scale of 0 to 10. In some embodiments, the subject exhibits a decrease of at least 0.5 numeric pain rating four weeks after nerve repair.

[0025] In some embodiments, the subject senses a Semmes-Weinstein Monofilament Test (SWMT) force using a SWMT filament of size greater than 6.65 g. In some embodiments, the subject senses a SWMT force using a SWMT filament of size less than 4.56 g 12 weeks after nerve repair.

[0026] In some embodiments, the subject exhibits a decrease of at least 1 numeric pain rating 12 weeks after nerve repair.

[0027] In some embodiments, the nerve treatment device comprises an at least partially enclosed chamber and the PEG solution is applied within the chamber.

[0028] In an eighth aspect of the present disclosure, provided herein is a kit comprising: a first solution; a second solution; a third solution; and instructions specifying a sequence for applying the first solution, the second solution and the third solution to a nerve repair site; wherein the first solution is a hypotonic saline solution having a calcium concentration of less than 500 ppm; the second solution is 50% PEG 3350 Da w / w in water; the third solution is Lactated Ringers Solution; and wherein the instructions specify the following method steps: a) applying at least 5 mL of the first solution is to first and second severed ends of a severed nerve; b) suturing the first and second severed ends together to form a sutured nerve region; c) placing the sutured nerve region within a nerve treatment device;d) applying no more than 2.5 mL of the second solution to the severed nerve region within the device; e) aspirating the second solution from the device; f) removing the sutured nerve region from the device; and g) irrigating the sutured nerve region with at least 10 mL of the third solution; wherein the sequence of the method steps is a), b), c), d), e), f) then g) in that order.

[0029] In a ninth aspect of the present disclosure, provided herein is a kit comprising: a first solution; a second solution; a third solution; a nerve treatment device; and instructions specifying a sequence for applying the first solution, the second solution and the third solution to a nerve repair site; wherein the first solution is a hypotonic saline solution having a calcium concentration of less than 500 ppm; the second solution is 50% PEG 3350 Da w / w in water; the third solution is Lactated Ringers Solution; and wherein the instructions specify the following method steps: a) applying at least 5 mL of the first solution is to first and second severed ends of a severed nerve; b) suturing the first and second severed ends together to form a sutured nerve region; c) placing the sutured nerve region within a nerve treatment device; d) applying no more than 2.5 mL of the second solution to the severed nerve region within the device; e) aspirating the second solution from the device; f) removing the sutured nerve region from the device; and g) irrigating the sutured nerve region with at least 10 mL of the third solution; wherein the sequence of the method steps is a), b), c), d), e), f) then g) in that order.

[0030] In some embodiments of the kits described herein, the instructions further specify that the first and second severed ends of the nerve are to be trimmed before applyingthe calcium-free hypotonic solution.In some embodiments, the first solution is a hypotonic saline that is calcium-free.

[0031] In some embodiments, the kits described herein are for use in treating a nerve injury in a subject, optionally wherein the nerve injury is a peripheral nerve injury.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1A-1E schematically illustrate multiperspective views of an example of a nerve treatment device that may be used to deliver therapeutic solutions to an isolated segment of a nerve for nerve repair as described herein. The treatment device has opposing slits which are positioned along an intersection with a front wall to created flanged endwalls. Figure 1A depicts a perspective view of the treatment device. Figure IB depicts a top view of the treatment device. Figure 1C depicts a right side view of the treatment device. Figure ID depicts a rear view looking down on a portion of the handle of the treatment device. Figure IE depicts a cross-sectional view of a section taken along a midline between left and right sides of the treatment device transverse to the longitudinal axis.

[0033] FIG. 2A shows changes in MHQ total score in subjects receiving the treatment method described herein (therapy group A) and in subjects receiving the standard of care (therapy group B) for all subjects.

[0034] FIG. 2B shows changes in MHQ total score change in subjects receiving the treatment method described herein (therapy group A) and in subjects receiving the standard of care (therapy group B) for subjects having a severed nerve from below the distal border of the brachial plexus to the wrist crease.

[0035] FIG. 2C shows changes in MHQ total score in subjects receiving the treatment method described herein (therapy group A) and in subjects receiving the standard of care (therapy group B) for subjects having a severed nerve from below the distal border of the wrist to the fingertip.

[0036] FIG. 2D shows MHQ total score by time in subjects receiving the treatment method described herein and in subjects receiving the standard of care.

[0037] FIG. 3 A shows static 2-point discrimination measurements in subjects receiving the treatment method described herein and in subjects receiving the standard of care.

[0038] FIG. 3B shows moving 2-point discrimination measurements in subjects receiving the treatment method described herein and in subjects receiving the standard of care.

[0039] FIG. 4A shows Semmes Weinstein Monofilament Test (SWMT) results in subjects receiving the treatment method described herein and in subjects receiving the standard of care after 12 weeks.

[0040] FIG. 4B shows Semmes Weinstein Monofilament Test (SWMT) results in subjects receiving the treatment method described herein and in subjects receiving the standard of care at various timepoints through 48 weeks.

[0041] FIG. 5 shows MRCC motor function test results after 48 weeks in subjects receiving the treatment method described herein and in subjects receiving the standard of care.

[0042] FIG. 6 shows percentage of responders based on PGIC score after 48 weeks in subjects receiving the treatment method described herein and in subjects receiving the standard of care.

[0043] FIG. 7A shows baseline NPRS scores for subjects receiving the treatment method described herein and for subjects receiving the standard of care for all subjects.

[0044] FIG. 7B shows changes in NPRS scores from baseline for subjects receiving the treatment method described herein and for subjects receiving the standard of care.

[0045] FIG. 7C shows changes in NPRS scores from baseline for subjects receiving the treatment method described herein and for subjects receiving the standard of care for subjects having a severed nerve from below the distal border of the brachial plexus to the wrist crease.

[0046] FIG. 7D shows changes in NPRS scores from baseline for subjects receiving the treatment method described herein and for subjects receiving the standard of care for subjects having a severed nerve from below the distal border of the wrist to the fingertip.

[0047] FIG. 7E shows NPRS at 4, 8, and 12 weeks after surgery for subjects receiving the treatment method described herein and for subjects receiving the standard of care.

[0048] FIG. 8 A shows baseline CISS scores for subjects receiving the treatment method described herein and for subjects receiving the standard of care.

[0049] FIG. 8B shows changes in CISS scores through Week 48 from baseline for subjects receiving the treatment method described herein and for subjects receiving the standard of care.

[0050] FIG. 8C shows CISS at 4, 8, and 12 weeks after surgery for subjects receiving the treatment method described herein and for subjects receiving the standard of care.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0051] In a first aspect of the present disclosure, provided herein is a method of repairing a severed nerve, the method comprising: applying at least 5 mL of hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the chamber, wherein the PEG solution is 50% PEG 3350 Da w / w in water; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with at least 10 mL of Lactated Ringers Solution.

[0052] In a second aspect of the present disclosure, also provided herein is a method of repairing a severed nerve in a subject reporting mild to moderate pain due to the severed nerve. In some embodiments, repairing the severed nerve in such patients using the methods described herein results in a greater and / or faster reduction in pain as compared to standard of care. In some embodiments, the pain level is determined using a numeric pain rating scale (NPRS). The NPRS scale is numerically rated from 0-10, with 0 being no pain, 1- 3 being mild pain, 4-6 being moderate pain, and 7-10 being severe pain. A subject is asked to make three pain ratings, corresponding to current, best and worst pain experienced over the past 24 hours. The average of the 3 ratings is used to represent the subject’s level of pain over the previous 24 hours. See McCaffery, M., Beebe, A., et al. (1989). Pain: Clinical manual for nursing practice, Mosby St. Louis, MO, which is incorporated herein by reference in its entirety.

[0053] In some embodiments described here, the molecular weight of the poly(ethylene glycol) (i.e., PEG) is a weight average molecular weight (Mw). In some such embodiments, the Mwof a polymer may be determined by techniques known in the art such as, but not limited to, size exclusion chromatography (SEC), gel permeation chromatography (GPC), static light scattering (SLS), dynamic light scattering, and ultracentrifugation. In some embodiments described here, the molecular weight of the poly(ethylene glycol) (i.e., PEG) isa number average molecular weight (Mn). In some such embodiments, the Mnof a polymer may be determined by techniques known in the art such as, but not limited to, measurement of colligative properties, osmotic pressure methods, and freezing point depression.

[0054] In some embodiments, the subject reports a numeric pain rating of from 2 to 6 on a scale of 0 to 10, and the method comprises: applying hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying a PEG solution to the severed nerve region within the chamber; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with a calcium-containing isotonic saline. Some embodiments include identifying a subject reporting a numeric pain rating of from 2 to 6 prior to repairing the nerve.

[0055] In some embodiments, the subject exhibits a decrease of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3 numeric pain rating four weeks after nerve repair. In some embodiments, the subject exhibits a decrease of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3 numeric pain rating eight weeks after nerve repair. In some such embodiments, the subject exhibits a decrease of at least 0.5 numeric pain rating four weeks after nerve repair. In some embodiments, the subject exhibits a decrease of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 numeric pain rating twelve weeks after nerve repair. In some such embodiments, the subject exhibits a decrease of at least 1.0 numeric pain rating twelve weeks after nerve repair. In some embodiments, the subject exhibits a decrease of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 numeric pain rating 24 weeks after nerve repair.

[0056] In a third aspect of the present disclosure, also provided herein is a method of increasing protective sensation in a hand of a subject having a severed nerve from below the distal border of the brachial plexus to the fingertip. Accordingly, in some embodiments, the subject exhibits decreased sensation in the hand due to the nerve injury, including decrease to the extent that protective sensation is diminished or lost. In some embodiments, the decreasein sensation is determined using the Semmes-Weinstein Monofilament Test (SWMT). The Semmes-Weinstein Monofilament Test (SWMT) is a clinical tool for use in the evaluation of peripheral nerve injuries before and / or after recovery. See, e.g, McGill et al., Diabet Med, 1998, 15: 615-617, which is incorporated herein by reference in its entirety. Subjects with high sensibility sense a SWMT test using fibers of size 2.83 - 4.31 g; subjects with little sensibility sense a SWMT test using fibers of size 4.56 - 6.65 g; and subjects with no sensibility sense a SWMT test using fibers of size greater than 6.65 g.

[0057] In some embodiments, the subject exhibits a Semmes-Weinstein Monofilament Test (SWMT) test using fibers of size greater than 6.65 g and the method comprises: applying hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying a PEG solution to the severed nerve region within the chamber; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with a calcium- containing isotonic saline. Some embodiments include identifying a subject exhibiting a SWMT test using fibers of size greater than 6.65 g prior to repairing the nerve.

[0058] In some embodiments, the subject exhibits a SWMT test using fibers of size less than 4.56 g 4, 8, 12, 24, or 48 weeks after nerve repair. In some such embodiments, the subject exhibits a SWMT test using fibers of size less than 4.56 g 12 weeks after nerve repair. In some embodiments, the subject exhibits a SWMT test using fibers of size 2.83 - 4.31 g 4 8, 12, 24, or 48 weeks after nerve repair. In some such embodiments, the subject exhibits a SWMT test using fibers of size 2.83 - 4.31 g 4 8, 12, 24, or 48 weeks after nerve repair.

[0059] In some embodiments of the methods described herein, the nerve is a peripheral nerve. In some such embodiments, the nerve is severed from below the distal border of the brachial plexus to the fingertip. In other embodiments, the nerve is severed from below the distal border of the brachial plexus to the wrist crease. In yet other embodiments, the nerve is severed from below the distal border of the wrist to the fingertip.

[0060] In some embodiments, the methods described herein include placing the sutured nerve region within an at least partially enclosed chamber. Non-limiting examples of the partially enclosed chamber is described in International Patent Publication No. WO2019 / 023274, which is incorporated by reference herein in its entirety. For example, in some embodiments, the partially enclosed chamber may be a nerve treatment device exemplified in FIG. 1A-1E.

[0061] FIG. 1A-1E schematically illustrate multi-perspective views of a treatment device 1100. Figures 1A-1E include examples of suitable, but non-limiting dimensions (in mm) for various portions of the treatment device 1100. Figure 1A depicts a perspective view of the treatment device 1100. Figure IB depicts a top view of the treatment device 1100. Figure 1 C depicts a right side view of the treatment device 1100. Figure ID depicts a rear view looking down on a portion of the handle 1132 of the treatment device 1100. Figure IE depicts a cross- sectional view of a section taken along a midline between left and right sides of the treatment device 1100 transverse to the longitudinal axis. The slits 1128 may be disposed along the right and left endwalls 1108, 1110 along an intersection between a front portion 1105 of the sidewall 1104 forming a front inner surface of containment chamber 1106 and the left and right portions 1109, 1111 of the sidewall 1104 forming the left and right inner surfaces of the containment chamber 1106. The slits 1128 may define a single flange 1130 on each endwall 1108, 1110. The flanges 1130 may form the majority of the surface area of the endwalls 1108, 1110 and may form the entire inner surface of the containment chamber 1106. The distal edges of the flanges 1130 may oppose the front sidewall 1105 that forms the intermediate body 1112 along the front surface of the treatment device 1100. The distal edges of the flanges 1130, in an unbiased configuration, may be positioned in close proximity to the front sidewall 1105, may be positioned in contact with the front sidewall 1105, or may partially overlap the left and right edges of the front sidewall 1105, similar to the distal edges of flanges 130 described elsewhere herein. The positioning of the slits 1128 as described which more definitively proportions the sidewall 1104 between a front sidewall 1105 and left and right sidewalls 1109, 1111 may make the front sidewall 1105 relatively more compliant. The front sidewall 1105 may be readily bendable in a forward direction away from the distal end of the flanges 1130, which may advantageously facilitate insertion of the nerve through the slits 1128 to be received in apertures 1136. The top edge of the front sidewall 1105 may be angled or beveled downward in the direction of the containment chamber 1106, which may advantageously help guide the nerve into the slits 1128 during introduction of the nerve into the treatment device 1100.

[0062] The apertures 1136 of treatment device 1100 may be disposed off-center in the direction transverse to the longitudinal axis on the endwalls 1108, 1110. For instance, the apertures 1136 may be disposed along the intersection of the front sidewall 1105 and the left and right sidewalls 1109, 1111. The slits 1128 may interest the circumferences of the apertures 1126 along the frontward most points of the circumferences as shown in FIG. 1A and 1C. The front wall 1105 may merge with the left and right sidewalls 1109, 1111 generally along a bottom and / or rear portion of the circumference of the apertures 1126. The positioning of an entire aperture 1136 underneath a single flange 1130 may advantageously make the flange 1130 more flexible as a longer horizontal length of the flange 1130 may be separable from the remainder of the endwall 1108, 1110.

[0063] As shown in Figure 1C, the containment chamber 1106 may comprise beveled surfaces 1150, as described elsewhere herein, interconnecting front, rear, left, and / or right inner surfaces of the containment chamber 1106 to a floor of the containment chamber 1106. The positioning of the slits 1128 and the apertures 1126 more toward the front wall 1105 may shift the floor of the containment chamber 1106 more toward the front of the body 1102 of the treatment device 1100.

[0064] The treatment device 1100 may comprise a handle 1132 having a downward angle as shown in Figure 1C. The handle 1132 may extend laterally from the body 1102 of the treatment device 1100 (e.g., from the top of the treatment device 1100) and then bend toward a downward direction. The distal end of the handle 1132 may extend to a vertical position above the bottom of the body 1102, approximately at the same level as the bottom of the body 1102 (as shown in Figure 1C), or below the bottom of the body 1102.

[0065] In some embodiments, the methods described herein further comprise trimming the first and second severed ends of the nerve before applying the hypotonic solution.

[0066] In the methods described herein, hypotonic saline is applied to the severed ends of the nerves to prime them prior to suturing. Hypotonic fluid administration moves fluids into cells due to osmosis. Additionally, administration of calcium-free hypotonic saline prevents calcium influx into the transected axon after injury to prevent further damage. In some embodiments, the calcium concentration of the hypotonic saline is less than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 550, 600, 700, 800, 900, or 1000 parts per million (ppm). Insome embodiments, the hypotonic saline is calcium-free. In some embodiments, at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mL of hypotonic saline is applied to first and second severed ends of the nerve. In some specific embodiments, at least 5 mL of hypotonic saline to first and second severed ends of the nerve.

[0067] In some embodiments, the methods described herein require applying a poly(ethylene glycol) (“PEG”) solution to the severed nerve region within the chamber. Application of a PEG solution may increase the speed and quality of recovery from nerve injury. In some embodiments, the PEG is a low molecular weight PEG. For example, the PEG may have a molecular weight of no more than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 kDa, or within a range defined by any two of the aforementioned molecular weights. In some embodiments, the PEG may have a molecular weight from about 1 kDa to about 15 kDa, from about 2 kDa to about 13 kDa, from about 3 kDa to about 5 kDa, from about 3 kDa to about 10 kDa, or from about 5 kDa to about 15 kDa. In some embodiments, the PEG may have a molecular weight of about 3.35 kDa (z.e., 3,350 Da). In some embodiments, no more than about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1,4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 or 5.0 mL of the PEG solution is allied to the severed nerve region. In some specific embodiments, no more that about 2.5 mL of the PEG solution is applied to the severed nerve region within the chamber. In some embodiments, the PEG solution is 50% PEG 3350 Da (w / w) in water. In some embodiments, the PEG solution is applied for about 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180 seconds or more prior to aspirating the PEG solution, or within a range defined by any two of the aforementioned values. In some embodiments, the PEG solution is applied for about 30-180 seconds, 60 to 150 seconds, or 90-120 seconds or more prior to aspirating the PEG solution.

[0068] In some embodiments, the methods described herein require irrigating the sutured nerve region with a calcium-containing isotonic saline. Irrigation of the sutured nerve region with excess isotonic calcium-containing solution dilutes residual PEG and restores transmembrane osmotic balance to the axons. In some embodiments, at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mL of a calcium-containing isotonic saline is applied to the sutured nerve region. In some specific embodiments, at least 10 mL of calcium-free hypotonic saline to the sutured nerve region. In some embodiments, the calcium-containingisotonic saline is Lactated Ringer’s Solution. Lactated Ringer’s Solution is a solution often used to treat dehydration and restore fluid balance. The solution contains sodium chloride, sodium lactate, potassium chloride and calcium chloride in water. One liter of Lactated Ringer’s Solution contains about 130 mmol of Na+, about 109 mmol Cl', about 28 mmol lactate ion, about 4 mmol K+, and about 1.5 mmol Ca2+.EXAMPLES

[0069] Some aspects of the embodiments discussed above are disclosed in further detail in the following example, which is not in any way intended to limit the scope of the present disclosure. Those in the art will appreciate that many other embodiments also fall within the scope of the methods of the present application, as is described herein above and in the claims.Example 1. Efficacy of Treatment of Acute Single Transected Peripheral Nerve Injury Occurring Below the Distal Border of the Brachial Plexus Requiring Surgical Repair

[0070] A randomized, patient and evaluator blinded, controlled study evaluating the safety and efficacy of the methods described herein compared to standard of care in the treatment of acute single transected peripheral nerve injury occurring below the distal border of the brachial plexus requiring surgical repair was conducted using a hybrid model of on-site and remote visits. The subjects in the study sustained a confirmed single transected peripheral nerve injury, which involves injury to motor and / or sensory function of the radial, median, or ulnar nerve with injury localized distal to the brachial plexus cord level to the fingertip. The subject’s nerve injury was classified as Sunderland’s Fourth and Fifth Degree (Class III), was amenable to minimal or acceptable tension, in direct, end-to-end repair. The surgical repair of the subjects occurred within 48 hours of injury. Subjects were at least 16 years of age and not older than 80 years of age. Subjects are evaluated at baseline and at weeks 4, 8, 12, 24, 36, and 48 weeks following surgical repairs.

[0071] The subjects in therapy group B (Tx-B) was the control group and received the standard of care (SOC) consisting of standard suture neurorrhaphy. The subjects in therapy group A (Tx-A) received the following treatment:1. Trim the nerve stumps as needed;2. Immediately apply Solution #1 to prime the injured nerve stumps for fusion;3. Immediately suture;4. Place isolation chamber under sutured nerve site;5. Apply Solution #2 via isolation chamber for - 90 - 120 seconds of exposure;6. Aspirate Solution #2 from isolation chamber as needed;7. Remove isolation chamber;8. Apply Solution #3 to irrigate, dilute and flush the surgical field;9. Close wound

[0072] Solution #1 was 5 mL of a sterile calcium-free hypotonic saline (priming); Solution #2 was 2.5 mL of a 3.35 kDa polyethylene glycol (fusogen), 50% in water; and Solution #3 was 10 mL of a sterile Lactated Ringer’s for Injection (irrigation). The isolation chamber is isolation chamber medical device for focal application of Solution #2 substantially similar to the one described with reference to Figures 1A-1E.Michigan Hand Outcomes Questionnaire (MHO)

[0073] The subjects were evaluated using Michigan Hand Outcomes Questionnaire (MHQ) total score. Chung etal., J Hand SurgAm. 1998; 23(4):575-87, incorporated herein by reference in its entirety. MHQ is a 37-item self-assessment instrument that measures disability along 6 domains: function, activities of daily living, pain, hand appearance, patient satisfaction, and work disability. The screening assessment of the MHQ should reflect the subject’s perception of functional ability seven days prior to their injury. Baseline assessment was conducted at week 4 after the repair. Change scores quantifying the amount of improvement for each domain were calculated for each participant by subtracting the score of the second administration of the MHQ from the score from the first. The range of MHQ Total Score is 0- 100, with 100 being the optimal score. FIG. 2A shows that at weeks 8, 12, 24, and 48, subjects in treatment group A had a greater MHQ total score change from baseline compared to subjects in the control treatment group B. FIG. 2B and 2C show the MHQ total score for subgroups of subjects have a nerve severed from the distal border of the brachial plexus to the wrist crease and from the distal border of the wrist to the fingertips, respectively. Similarly, FIG. 2D shows that subjects in treatment group A had a higher MHQ total score compared to subjects in the control treatment group B. The data for the MHQ total score change results at different time points post-surgery may be found in Table 1, which shows total MHQ scores with changes from baseline in parentheses.Table 1. - MHO total score change results by treatment group.Two-point Discrimination (2PD) Tests

[0074] Subjects were also evaluated using Medical Research Council Classification (MRCC) two-point discrimination (2PD) tests. These tests are commonly used neurosensory tests to assess mechanoperception in the clinical settings and measure the innervation density by testing the ability to discern the difference between 1 and 2 pressure points. The assessment was based on injury location. Both static and moving assessments were done on the ulnar and radial sides on the affected digits only (palmar crease to fingertip). The nerve sensory endpoint includes the change from baseline of MRCC sensory scale scores at the visits 4, 8, 12, 24, 36 and 48 weeks. The assessments were performed by a blinded evaluator. The scale is commonly used for grading the sensory outcome after peripheral nerve surgery. This scale is categorized into S0-S4: SO is the absence of sensibility; SI is the recovery of deep cutaneous pain; S2 is the return of superficial cutaneous pain and some degree of tactile sensibility; S3 is the return of superficial cutaneous pain and tactile sensibility without over response; and S4 is the complete recovery. MacKinnon et al., Plast Reconstr Surg 85:419-424, 1990, which is incorporated herein by reference in its entirety.

[0075] Static 2PD measures the innervation density (number of nerves present in an area) by testing the ability to discern the difference between 1 and 2 static pressure points. Moving 2-point discrimination returns earlier than static 2-point discrimination. Moving 2PD is used to determine progress in return of sensation. A 2-point disk-criminator was used to determine the shortest distance, in millimeters, that the subject can feel the two, not one, points.Each disk-criminator measures a different range of 8 labeled, fixed 2-point intervals ranging from 1 mm to 25 mm. Responders were classified as those subjects having a sensory scale score of S3 or S4. FIG. 3A shows the static 2PD results for subjects in treatment group A and subjects in the control treatment group B up to week 48, while FIG. 3B shows moving 2PD results for subjects in treatment group A and subjects in the control treatment group B up to week 12. With the exception of the week 12 moving 2PD measurement, subjects in treatment group A exhibited a higher responder rate than subjects in the control treatment group B. At week 24, subjects in treatment group A had a responder rate of 77.8% and 62.8% for the static 2PD and moving 2PD tests, respectively, while treatment group B had a had a responder rate of 64.3% and 61.5% for the static 2PD and moving 2PD tests, respectively. At week 36, subjects in treatment group A had a responder rate of 66.7% and 85.7% for the static 2PD and moving 2PD tests, respectively, while treatment group B had a responder rate of 36.4% for each of the static 2PD and moving 2PD tests. At week 48, subjects in treatment group A had a responder rate of 62.5% and 66.7% for the static 2PD and moving 2PD tests, respectively, while treatment group B had a responder rate of 50.0% and 54.5% for the static 2PD and moving 2PD tests, respectively. The data for the 2PD results may be found in Table 2.Table 2, - Response to 2-point discrimination tests by treatment group.Semmes Weinstein Monofilament Test (SWMT)

[0076] The Semmes Weinstein Monofilament Test (SWMT) was assessed based on location of nerve injury. SWMT is used to assess perception of cutaneous pressure threshold, which reflect reinnervation of peripheral targets. For sensory only (digital injuries), the ulnar and radial sides on the affected digits were tested (palmar crease to fingertip). For motor or mixed motor injuries, the testing was done based on the regions of the hand affected by the ulnar, radial, or medial nerve injury. This assessment was performed during the baseline period. The follow-up assessments are made at Weeks 4, 8, 12, 24, 36 and 48. Assessments were conducted by a blinded evaluator. The subjects served as their own control by comparing right to left sides. SWMT provides information on protective sensation, the rigorous system can detect relatively minor differences in sensory function, and changes will occur early in nerve injury. The assessment tool consists of a set of monofilaments that vary in thickness and diameter, the gradient forces of these monofilaments range from 0.086 gm to 448 gm. The Sensory Evaluator was individually calibrated to deliver its targeted force within a 5% standard deviation. Normal value in the hand is in the range of the green filament (1.65 to 2.83 mN). FIG. 4A shows SWMT results for the affected nerve 12 weeks after surgery. A significantly larger percentage of subjects in treatment group A had higher sensibility in the affected digits than subjects in the control treatment group B. Additionally, it was observed that after 12 weeks, a significantly higher percentage subjects in control treatment group B has no sensibility as comparted with those subjects in treatment group A. At Week 48, none of the subjects in Treatment Group A had a loss sensation as compared to 5.3 percent of the subjects in Treatment Group B (FIG. 4B). This was also observed at 24 weeks and 36 weeks after surgery. The data for the SWMT may be found in Table 3.Table 3, - Responders to SWMT at selected timepointsMRCC Motor Function Test

[0077] The MRCC Motor Scale score is assessed based on location of injury. This assessment was conducted on motor and mixed motor nerve injuries only. The MRCC-motor assessment was performed during the baseline period. The follow-up assessments were at Weeks 4, 8, 12. Additional assessments were made at Week 24, 36 and 48. Assessments were made by a blinded evaluator. Strength can best be assessed by isolating an individual muscle group and comparing power with that of the patient. It can be conducted to assess larger muscles or muscle groups as well as intrinsic muscles of the hand. Assessments were made on a 5-point scale, where 0 / 5 is no muscle activation whatsoever; 1 / 5 is muscle activation without limb movement; 2 / 5 implies that the limb can be moved only when gravity is taken out of the equation; 3 / 5 means that the subject can overcome gravity but not resistance; 4 / 5 (or 4+ or 4- ) implies weakness with enough strength to overcome varying degrees of physical resistance; and 5 / 5 is full strength. The results of the motor function test are provided in FIG. 5, which shows the number of patients at 48 weeks with scores of 3 / 5 or greater.Patient Global Impression of Change (PGIC)

[0078] Patient Global Impression of Change was determined using a questionnaire and was assess during the baseline period. Follow-up assessments are at Weeks 4, 8, 12, 24, 36 and 48. The PGIC assesses all aspects of patients' health and assesses if there has been an improvement or decline in clinical status. The percentage of responders based on PGIC score for subjects in both treatment groups are shown in FIG. 6. Four weeks after surgery, subjects in treatment groups A and B both included a similar percentage of responders. However, eight weeks after surgery, subjects in treatment group A had a larger percentage of responders (76.5%) as compared to subjects in treatment group B (47.8%. A similar observation was madetwelve weeks after surgery, with treatment group A having a larger percentage of responders (70.6%) as compared to subjects in treatment group B (37.5%). At 24 weeks after surgery, treatment group A had a larger percentage of responders (80.0%) as compared to subjects in treatment group B (52.4%), while at 48 weeks after surgery, treatment group A had a larger percentage of responders (86.7%) as compared to subjects in treatment group B (80.0%).Numeric Pain Rating Scale (NPRS)

[0079] NPRS were reported by subjects and was assessed during the baseline period. Follow-up assessments are at Weeks 4, 8, 12, 24, 36 and 48. The NPRS is used to assess for pain and to determine pain intensity. The test measured single dimension of global pain intensity at rest or with activity. The patient was asked to make three pain ratings, corresponding to current, best and worst pain experienced over the past 24 hours. The average of the 3 ratings was used to represent the subject’s level of pain over the previous 24 hours. The NPRS scale is numerically rated from 0- 10, with 0 being no pain, 1 -3 being mild pain, 4- 6 being moderate pain, and 7-10 being severe pain. Baseline pain in both treatment groups were similar (FIG. 7A). However, NPRS assessment at Weeks 4, 8, and 12 show a greater decline from baseline for subjects in treatment group A as compared with those in standard of care treatment group B (FIG. 7B) through Week 12. This trend was also observed at Weeks 24, 36, and 48 (FIG. 7B). Each of these timepoints shows a greater decline from baseline for subjects in treatment group A as compared with those in standard of care treatment group B. The trend is observed through Week 24 for the subject population as a whole and also for those subjects having a severed nerve from below the distal border of the brachial plexus to the wrist crease (FIG. 7C) and subjects having a severed nerve from below the distal border of the wrist to the fingertip (FIG. 7D). Overall NPRS pain ratings were also lower at Weeks 4, 8, and 12 for subjects in treatment group A as compared with those in standard of care treatment group B (FIG. 7E). This trend was also observed at Week 24, with a mean NPRS score of 1.70 for subjects in treatment group A as compared to an NPRS score of 3.03 for subjects in control treatment group B. At Week 48, subjects in treatment group A had a mean NPRS score of 1.63 for subjects in treatment group A as compared to an NPRS score of 3.03 for subjects in control treatment group B.Cold Intolerance Symptom Severity (CISS)

[0080] Cold sensitivity is a complex symptom, which may present as pain, numbness, stiffness, weakness, swelling and change in skin color. CISS is used to evaluate sensitivity of cold intolerance during daily life. Cold sensitivity, described as “an exaggerated or abnormal reaction to cold exposure of the injured part, causing discomfort or the avoidance of cold,” is a common complaint following a variety of hand injuries and diseases. Carlsson et al., BMC Musculoskeletal Disord 2010, 11:89; Tark et al., J Hand Surg [Am] 1989, 14(1):17— 27, which is incorporated herein by reference in its entirety. The Cold Intolerance Symptom Severity (CISS) was used to evaluate sensitivity of cold intolerance during daily life. Ruijs et al. J Hand SurgBr. 2006; 31 :533-6, which is incorporated herein by reference in its entirety. The CISS questionnaire was performed during the baseline period and was self-administered. The follow-up assessments are at Weeks 4, 8, 12, 24 and 48. The CISS score is a reflection of symptom severity, with 4 being the lowest severity and 100 being the highest severity.

[0081] Baseline CISS is reported in FIG. 8A. At Weeks 8, 12, 24, and 48subjects in therapy group B show a greater increase from baseline as compared to subjects in treatment group A (FIG. 8B). Overall CISS ratings were also higher at Weeks 4, 8, and 12 for subjects in treatment group B as compared with those in standard of care treatment group A (FIG. 8C). At Weeks 24 and 48, subjects in therapy group B also show a greater overall CISS rating as compared to subjects in treatment group A.

[0082] While the present application has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the present application. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present application. All such modifications are intended to be within the scope of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A method of repairing a severed nerve, the method comprising: applying at least 5 mL of hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the chamber, wherein the PEG solution is 50% PEG 3350 Da w / w in water; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with at least 10 mL of Lactated Ringers solution.

2. The method of claim 1, further comprising trimming the first and second severed ends of the nerve before applying the calcium-free hypotonic solution.

3. The method of claim 1 or claim 2, wherein the hypotonic saline is calcium-free.

4. The method of any one of claims 1 to 3, wherein the nerve is a peripheral nerve.

5. The method of claim 4, wherein the nerve is severed from below the distal border of the brachial plexus to the fingertip.

6. A method of repairing a severed nerve in a subject reporting a numeric pain rating of from 2 to 6 on a scale of 0 to 10, the method comprising: applying hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying a PEG solution to the severed nerve region within the chamber; aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with a calcium- containing isotonic saline;wherein the subject exhibits a decrease of at least 0.5 numeric pain rating four weeks after nerve repair.

7. The method of claim 6, further comprising trimming the first and second severed ends of the nerve before applying the calcium-free hypotonic solution.

8. The method of claim 6 or 7, wherein the nerve is a peripheral nerve.

9. The method of claim 8, wherein the nerve is severed from below the distal border of the brachial plexus to the fingertip.

10. The method of any one of claims 6 to 9, wherein the subject exhibits a decrease of at least 1 numeric pain rating 12 weeks after nerve repair.

11. The method of any one of claims 6 to 10, comprising applying at least 5 mL of calcium-free hypotonic saline to first and second severed ends of the nerve.

12. The method of any one of claims 6 to 11, wherein the hypotonic saline is calcium-free.

13. The method of any one of claims 6 to 12, wherein no more than 2.5 mL of the PEG solution is applied to the severed nerve region within the chamber.

14. The method of any one of claims 6 to 13 , wherein the PEG solution is 50% PEG 3350 Da w / w in water.

15. The method of any one of claims 6 to 14, wherein the calcium-containing isotonic saline is Lactated Ringers solution.

16. The method of any one of claims 6 to 15, wherein the sutured nerve region is irrigated with at least 10 mL of Lactated Ringers solution.

17. A method of increasing protective sensation in a hand of a subject having a severed nerve from below the distal border of the brachial plexus to the fingertip, wherein the subject senses a Semmes- Weinstein Monofilament Test (SWMT) force using a SWMT filament of size greater than 6.65 g, the method comprising: applying hypotonic saline to first and second severed ends of the nerve, wherein the hypotonic saline has a calcium concentration of less than 500 ppm; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within an at least partially enclosed chamber; applying a PEG solution to the severed nerve region within the chamber;aspirating the PEG solution from the chamber; removing the sutured nerve region from the chamber; and irrigating the sutured nerve region with a calcium- containing isotonic saline; wherein the subject senses a SWMT force using a SWMT filament of size less than 4.56 g 12 weeks after nerve repair.

18. The method of claim 17, further comprising trimming the first and second severed ends of the nerve before applying the calcium-free hypotonic solution.

19. The method of claim 17 or 18, wherein the subj ect exhibits a decrease of at least 1 numeric pain rating 12 weeks after nerve repair.

20. The method of any one of claims 17 to 19, comprising applying at least 5 ml of calcium-free hypotonic saline to first and second severed ends of the nerve.

21. The method of any one of claims 17 to 20, wherein the hypotonic saline is calcium-free.

22. The method of any one of claims 17 to 21, wherein no more than 2.5 mL of the PEG solution is applied to the severed nerve region within the chamber.

23. The method of any one of claims 17 to 22, wherein the PEG solution is 50% PEG 3350 Da w / w in water.

24. The method of any one of claims 17 to 23, wherein the calcium-containing isotonic saline is Lactated Ringers solution.

25. The method of any one of claims 17 to 24, wherein the sutured nerve region is irrigated with at least 10 mL of Lactated Ringers solution.

26. A PEG solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of a hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within a nerve treatment device; applying no more than 2.5 mL of the PEG solution to the severed nerve region within the device; aspirating the PEG solution from the device; andremoving the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of a Lactated Ringers Solution; wherein the hypotonic saline has a calcium concentration of less than 500 ppm; and wherein the PEG solution is 50% PEG 3350 Da w / w in water.

27. The PEG solution for use according to claim 26, wherein the PEG solution is administered in combination with the hypotonic saline solution and the Lactated Ringers solution.

28. A hypotonic saline solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of the hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within nerve treatment device; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the device; aspirating the PEG solution from the device; and removing the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of a Lactated Ringers Solution; wherein the hypotonic saline has a calcium concentration of less than 500 ppm; and wherein the PEG solution is 50% PEG 3350 Da w / w in water.

29. The hypotonic saline solution for use according to claim 28, wherein the hypotonic saline solution is administered in combination with the PEG solution and the Lactated Ringers solution.

30. A Lactated Ringers solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of a hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within a nerve treatment device; applying no more than 2.5 mL of a PEG solution to the severed nerve region within the device;aspirating the PEG solution from the device; and removing the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of the Lactated Ringers Solution; wherein the hypotonic saline has a calcium concentration of less than 500 ppm; and wherein the PEG solution is 50% PEG 3350 Da w / w in water.

31. The Lactated Ringers solution for use according to claim 30, wherein the Lactated Ringers solution is administered in combination with the hypotonic saline solution and the PEG solution.

32. A combination of a hypotonic saline solution, a PEG solution and a Lactated Ringers solution for use in treating a nerve injury in a subject, wherein treatment comprises: applying at least 5 mL of the hypotonic saline solution to first and second severed ends of a nerve; suturing the first and second severed ends together to form a sutured nerve region; placing the sutured nerve region within nerve treatment device; applying no more than 2.5 mL of the PEG solution to the severed nerve region within the device; aspirating the PEG solution from the device; and removing the sutured nerve region from the device; and irrigating the sutured nerve region with at least 10 mL of Lactated Ringers Solution; wherein the hypotonic saline has a calcium concentration of less than 500 ppm; and wherein the PEG solution is 50% PEG 3350 Da w / w in water.

33. The PEG solution for use according to any one of claims 26 or 27, the hypotonic saline solution for use according to any one of claims 28 or 29, the Lactated Ringers solution for use according to any one of claims 30 and 31 , or the combination for use according to claim 32, wherein the PEG solution, the hypotonic saline solution and the Lactated Ringers solution are administered in the following sequence: a) the hypotonic saline solution; b) the PEG solution; and c) the Lactated Ringers; wherein the order of the sequence is a), b) then c).

34. The PEG solution for use according to any one of claims 26, 27 or 33, the hypotonic saline solution for use according to any one of claims 28, 29 or 33, the Lactated Ringers solution for use according to any one of claims 30, 31 or 33, or the combination for use according to any one of claims 32 or 33, wherein treatment further comprises trimming the first and second severed ends of the nerve before applying the calcium-free hypotonic solution.

35. The PEG solution for use according to any one of claims 26, 27, 33 or 34, the hypotonic saline solution for use according to any one of claims 28, 29, 33 or 34, the Lactated Ringers solution for use according to any one of claims 30, 31, 33 or 34, or the combination for use according to any one of claims 32 - 34, wherein the hypotonic saline is calcium-free.

36. The PEG solution for use according to any one of claims 26, 27 or 33 - 35, the hypotonic saline solution for use according to any one of claims 28, 29 or 33 - 35, the Lactated Ringers solution for use according to any one of claims 30, 31 or 33 - 35, or the combination for use according to any one of claims 32 - 35, wherein the nerve is a peripheral nerve.

37. The PEG solution for use according to any one of claims 26, 27 or 33 - 36, the hypotonic saline solution for use according to any one of claims 28, 29 or 33 - 36, the Lactated Ringers solution for use according to any one of claims 30, 31 or 33 - 36, or the combination for use according to any one of claims 32 - 36, wherein the nerve injury is a severed nerve.

38. The PEG solution for use according to claim 37, the hypotonic saline solution for use according to claim 37, the Lactated Ringers solution for use according to claim 37, or the combination for use according to claim 37, wherein the nerve is severed from below the distal border of the brachial plexus to the fingertip.

39. The PEG solution for use according to any one of claims 26, 27 or 33 - 38, the hypotonic saline solution for use according to any one of claims 28, 29 or 33 - 38, the Lactated Ringers solution for use according to any one of claims 30, 31 or 33 - 38, or the combination for use according to any one of claims 32 - 38, wherein the subject reports a numeric pain rating of from 2 to 6 on a scale of 0 to 10.

40. The PEG solution for use according to claim 39, the hypotonic saline solution for use according to claim 39, the Lactated Ringers solution for use according to claim 39, or the combination for use according to claim 39, wherein the subject exhibits a decrease of at least 0.5 numeric pain rating four weeks after nerve repair.

41. The PEG solution for use according to claim 38, the hypotonic saline solution for use according to claim 38, the Lactated Ringers solution for use according to claim 38, or the combination for use according to claim 38, wherein the subject senses a Semmes- Weinstein Monofilament Test (SWMT) force using a SWMT filament of size greater than 6.65 g.

42. The PEG solution for use according to claim 41, the hypotonic saline solution for use according to claim 41, the Lactated Ringers solution for use according to claim 41, or the combination for use according to claim 41 , wherein the subject senses a SWMT force using a SWMT filament of size less than 4.56 g 12 weeks after nerve repair.

43. The PEG solution for use according to any one of claims 39 - 42, the hypotonic saline solution for use according to any one of claims 39 - 42, the Lactated Ringers solution for use according to any one of claims 39 - 42, or the combination for use according to any one of claims 39 - 42, wherein the subject exhibits a decrease of at least 1 numeric pain rating 12 weeks after nerve repair.

44. The PEG solution for use according to any one of claims 26, 27 or 33 - 43, the hypotonic saline solution for use according to any one of claims 28, 29 of 33 - 43, the Lactated Ringers solution for use according to any one of claims 30, 31 or 33 - 43, or the combination for use according to any one of claims 32 - 43, wherein the nerve treatment device comprises an at least partially enclosed chamber and the PEG solution is applied within the chamber.

45. A kit comprising: a first solution; a second solution; a third solution; and instructions specifying a sequence for applying the first solution, the second solution and the third solution to a nerve repair site; wherein the first solution is a hypotonic saline solution having a calcium concentration of less than 500 ppm; the second solution is 50% PEG 3350 Da w / w in water; the third solution is Lactated Ringers Solution; and wherein the instructions specify the following method steps: h) applying at least 5 mL of the first solution is to first and second severed ends of a severed nerve;-SO-i) suturing the first and second severed ends together to form a sutured nerve region; j) placing the sutured nerve region within a nerve treatment device; k) applying no more than 2.5 mL of the second solution to the severed nerve region within the device; l) aspirating the second solution from the device; m) removing the sutured nerve region from the device; and n) irrigating the sutured nerve region with at least 10 mL of the third solution; wherein the sequence of the method steps is a), b), c), d), e), f) then g) in that order.

46. A kit comprising: a first solution; a second solution; a third solution; a nerve treatment device; and instructions specifying a sequence for applying the first solution, the second solution and the third solution to a nerve repair site; wherein the first solution is a hypotonic saline solution having a calcium concentration of less than 500 ppm; the second solution is 50% PEG 3350 Da w / w in water; the third solution is Lactated Ringers Solution; and wherein the instructions specify the following method steps: h) applying at least 5 mL of the first solution is to first and second severed ends of a severed nerve; i) suturing the first and second severed ends together to form a sutured nerve region; j) placing the sutured nerve region within a nerve treatment device; k) applying no more than 2.5 mL of the second solution to the severed nerve region within the device; l) aspirating the second solution from the device; m) removing the sutured nerve region from the device; and n) irrigating the sutured nerve region with at least 10 mL of the third solution; wherein the sequence of the method steps is a), b), c), d), e), f) then g) in that order.

47. The kit according to any one of claims 45 or 46, wherein the instructions further specify that the first and second severed ends of the nerve are to be trimmed before applying the calcium-free hypotonic solution.

48. The kit according to any one of claims 45 to 47, wherein first solution is a hypotonic saline that is calcium-free.

49. The kit according to any one of claims 45 to 48, for use in treating a nerve injury in a subject, optionally wherein the nerve injury is a peripheral nerve injury.

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