Compositions and methods for treating neurological disorders

Abstract

The present invention provides a method for selectively targeting peripheral nerves and providing sustained pain treatment without damaging surrounding tissue. [Solution] A method includes injecting a biocompatible ice slurry into or around one or more peripheral nerves of a subject for a period of time sufficient to inhibit the peripheral nerves, wherein the injected biocompatible ice slurry cools the peripheral nerves and the inhibition is reversible.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 62 / 042,979, filed on August 28, 2014; U.S. Provisional Patent Application No. 62 / 121,472, filed on February 26, 2015; and U.S. Provisional Patent Application No. 62 / 121,329, filed on February 26, 2015. The entire disclosure content of the above - mentioned provisional applications is incorporated herein by reference. This application includes the disclosure content related to International Application No. PCT / US2015 / (Attorney Docket No. 051588 - 22211WO1(000386)), filed on August 27, 2015, and the entire disclosure content thereof is incorporated herein by reference.

Background Art

[0002] Chronic pain of peripheral nerves is a common problem in the general population, and particularly in veterans. Chronic pain of peripheral nerves can arise from many causes, such as surgery, trauma, nerve tumors, metabolic or genetic disorders, infections, or can be idiopathic. It is estimated that 20 - 30% of all limb injuries in U.S. military personnel are accompanied by peripheral nerve damage. Severe peripheral nerve injury and amputation can have a devastating impact on the quality of life due to intractable neuropathic pain. The treatment of intractable nerve pain has been attempted using, for example, oral pain medications including narcotics, non - steroidal anti - inflammatory drugs (NSAIDs), surgery, and various percutaneous means including high - frequency and alcohol ablation. However, these treatments are associated with many complications, including narcotic addiction and the need for multiple procedures. Overall, the current treatment options for chronic peripheral nerve pain have not been able to achieve satisfactory results.

[0003] Cryoneurolysis is the use of cooling to a target nerve. Cryoneurolysis is a specialized technique for providing long-term pain relief in the setting of interventional pain management. Applying cooling to a nerve creates a conduction block similar to the effect of local anesthesia, and when the nerve freezes, it causes Wallerian degeneration of the nerve. Cryoneurolysis has been used for years to treat, at the very least, phantom limb pain, secondary pain associated with trigeminal neuralgia, post-thoracotomy chest wall pain, pain of peripheral neuritis, and pain of post-herpetic neuralgia. This technique involves a probe that is 1.4 to 2 millimeters in size and utilizes a pressurized gas (e.g., nitrous oxide or carbon dioxide) at 600 to 800 psi to create a cold temperature of -89°C or lower at the tip of the probe by adiabatic cooling based on the Joule-Thompson effect, thereby creating an ice ball in the target area. The probe is placed directly on the nerve and any tissue, which comes into contact with the probe and is destroyed due to the extreme cold temperature used. This procedure is not selective because the surrounding tissue is almost always damaged or injured. In addition, nerve damage in these temperature ranges will be permanent.

[0004] A procedure involving cryoneurolysis that selectively targets peripheral nerves and continuously treats pain without damaging the surrounding tissue is particularly desirable.

Summary of the Invention

[0005] In one aspect, the present invention provides a method for reversibly inhibiting a peripheral nerve in a subject in need thereof. The method includes providing a biocompatible ice slurry to a peripheral nerve in the subject for a duration sufficient to inhibit the peripheral nerve, wherein the inhibition is reversible. In some embodiments, the inhibition disappears after a period of about 5 months or less has elapsed. The peripheral nerve targeted for inhibition may be a subcutaneous nerve; a somatic nerve including a sensory nerve, a motor nerve, a cranial nerve, or a spinal nerve; or an autonomic nerve including a sympathetic nerve, a parasympathetic nerve, or an enteric nerve. In some embodiments, the biocompatible ice slurry is provided along the perineural sheath of the peripheral nerve.

[0006] In one embodiment, the biocompatible ice slurry includes ice particles and a Ringer's lactate solution or a lactate electrolyte solution.

[0007] In another embodiment, the biocompatible ice slurry further includes hetastarch or dextrose.

[0008] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 20% glucose.

[0009] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 20% glycerol.

[0010] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 6% hetastarch.

[0011] In yet another embodiment, the biocompatible ice slurry includes ice particles and physiological saline.

[0012] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 20% glycerol.

[0013] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 20% dextrose.

[0014] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 5% ethanol.

[0015] In yet another embodiment, the biocompatible ice slurry further includes about 0.1% to about 10% polyvinyl alcohol.

[0016] In yet another embodiment, the biocompatible ice slurry further comprises at least one ion, sugar, polysaccharide, lipid, oil, lysophosphatidylcholine, amino acid, caffeine, surfactant, antimetabolite, or a combination thereof. Examples of the at least one ion include, but are not limited to, calcium, potassium, hydrogen, chlorine, magnesium, sodium, lactate, phosphate, zinc, sulfur, nitrate ion, ammonium, carbonate ion, hydroxide ion, iron, barium, salts thereof, or a combination thereof, including these salts. Examples of the at least one sugar include, but are not limited to, glucose, sorbitol, mannitol, hetastarch, sucrose, or a combination thereof. Examples of the at least one oil include, but are not limited to, canola oil, coconut oil, corn oil, cottonseed oil, flaxseed oil, olive oil, palm oil, peanut oil, safflower oil, soybean oil, sunflower oil, or a combination thereof.

[0017] In yet another embodiment, the surfactant is a detergent. Examples of the detergent include, but are not limited to, deoxycholate, sodium tetradecyl sulfate, polidocanol, polysorbate (including polysorbate 20 (polyoxyethylene (20) sorbitan monolaurate), polysorbate 40 (polyoxyethylene (20) sorbitan monopalmitate), polysorbate 60 (polyoxyethylene (20) sorbitan monostearate), polysorbate 80 (polyoxyethylene (20) sorbitan monooleate)), sorbitan ester, poloxamer, or a combination thereof.

[0018] In yet another embodiment, the biocompatible ice slurry comprises a peritoneal dialysis solution.

[0019] In yet another embodiment, the biocompatible ice slurry cools nerves from about 5°C to about -40°C.

[0020] In yet another embodiment, the biocompatible ice slurry has a first equilibrium temperature of about 4°C to about -30°C.

[0021] In yet another embodiment, the biocompatible ice slurry has a second equilibrium temperature of from about 2°C to about -30°C.

[0022] In yet another embodiment, the ice particles are spherical or rounded with a diameter of from about 1 mm to about 0.01 mm.

[0023] In yet another embodiment, the biocompatible ice slurry further comprises agents including, but not limited to, vasoconstrictors, corticosteroids, NSAIDs, anesthetics, glucocorticoids, lipoxygenase inhibitors, and combinations thereof. Vasoconstrictors include, but are not limited to, epinephrine or norepinephrine. Anesthetics include, but are not limited to, lidocaine, bupivacaine, prilocaine, tetracaine, procaine, mepivacaine, QX-314, etidocaine, or combinations thereof.

[0024] In yet another embodiment, the biocompatible ice slurry is injected. The injection may be administered into or around any peripheral nerve, any nerve that conducts pain, or any nerve that has sustained an injury that causes pain or a disease, including, but not limited to, subcutaneous nerves, trigeminal nerves, ilioinguinal nerves, intercostal nerves, interscalene nerves, intercostal nerves, supraclavicular nerves, subclavian nerves, axillary nerves, paravertebral nerves, nerves of the transverse abdominal muscle, lumbar plexus, femoral nerves, genitals, celiac plexus, and sciatic nerves.

[0025] In yet another embodiment, the biocompatible ice slurry is applied to the subject's peripheral nerves by pressure pumping of the slurry's swelling.

[0026] In yet another embodiment, pressure is applied to the injection site to reduce blood flow.

[0027] In yet another embodiment, the tissue including the peripheral nerve is cooled externally before, during, or after providing the biocompatible ice slurry.

[0028] In yet another embodiment, the ice content of the biocompatible ice slurry is monitored by ultrasound or imaging.

[0029] In yet another embodiment, the subject in need of treatment suffers from disorders including, but not limited to, neuropathic pain, pain of diabetic neuropathy, trigeminal neuralgia, post-herpetic neuralgia, phantom limb pain, itch or pain associated with cancer, itch or pain of burns, lichen sclerosus et atrophicus, scalp itch, dysesthetic low back pain, atopic dermatitis, eczema, psoriasis, lichen planus, vulvar itch, vulvodynia, chronic simple lichen, prurigo nodularis, itch mediated by sensory nerves, peripheral neuropathy, peripheral nerve injury, post-thoracotomy pain, incision pain, chest pain, coccydynia, low back pain (with or without radiculopathy), scar, neuroma, acute postoperative pain, lumbar facet joint syndrome and cutaneous pain disorders.

[0030] Cutaneous pain disorders include, but are not limited to, reflex sympathetic dystrophy (RSD), phantom limb pain, neuroma, post-herpetic neuralgia, headache, occipital neuralgia, tension headache and vulvodynia.

[0031] In yet another embodiment, the subject in need of treatment suffers from movement disorders including, but not limited to, hemifacial spasm, bladder spasm, pharyngeal spasm and gustatory hyperhidrosis.

[0032] Other features and advantages of the present invention will be apparent from the detailed description and the claims. Accordingly, other aspects of the present invention are described in the following disclosure and are within the scope of the present invention.

[0033] The following detailed description is given by way of example and is not intended to limit the present invention to the specific embodiments described, which will be understood in conjunction with the accompanying drawings and incorporated herein by reference.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0035] Definition Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present application, including definitions, will control.

[0036] Unless otherwise stated explicitly or apparent from the context, as used herein, the term "about" is understood to be within the scope of normal variation in the art, e.g., within 2 standard deviations of the mean. "About" is understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. Unless otherwise apparent from the context, all numerical values given herein are modified by the term "about".

[0037] As used herein, the term "biocompatible" refers to a substance or solution that has the ability to exist with living tissue or an organism without causing harm.

[0038] As used herein, the term "ice" refers to water in the solid state (i.e., frozen water).

[0039] As used herein, the term "water" refers to H2O and all isotopes of H2O including D2O, T2O, etc., and mixtures thereof.

[0040] As used herein, the term "aqueous solution / aqueous slurry" refers to a solution / slurry containing H2O and all isotopes of H2O including D2O, T2O, etc., and mixtures thereof. Such solutions may contain water in the solid state, semi-solid state and / or liquid state.

[0041] As used herein, the term "equilibrium" or "equilibrium temperature" refers to the temperature between the temperature of the slurry and the temperature of the tissue at the first contact of the slurry with the tissue.

[0042] As used herein, "reversibly inhibiting" a peripheral nerve refers to a loss of nerve function that recovers over time. Examples of loss of function would include, for example, a decrease in the thermal or mechanical sensation of the nerve.

[0043] The ranges given in this specification are to be understood as a shorthand for all values included in the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range (and parts thereof, unless otherwise clearly indicated by the context) from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50.

[0044] "Slurry" refers to solid phase particles (e.g., ice particles) suspended in a biocompatible liquid phase solution. The slurry may also contain gas phase bubbles.

[0045] "Subject" is a vertebrate and includes any member of the mammalian group, including humans, domestic animals, farm animals, zoo animals, sports animals or pets, such as horses, cats, dogs, mice, rabbits, pigs, sheep, goats, cows and more advanced primates.

[0046] As used herein, the terms "treat", "treating", "treatment", etc. refer to reducing or alleviating a disorder and / or symptoms associated with the disorder. Without being excluded, it will be understood that treating a disorder or condition does not require the disorder, condition or symptoms associated with the disorder to be completely eliminated.

[0047] In the present disclosure, "comprise", "comprising", "containing", "having", etc. may have the meaning assigned in the United States Patent Law, and may also mean "include", "including", etc. Similarly, "consisting essentially of" or "essentially constituting" has the meaning assigned in the United States Patent Law. This term is inclusive and allows for the presence of more than what is recited, as long as the basic or novel features of what is recited are not changed by the presence of more than what is recited, provided that prior art embodiments are excluded.

[0048] Other definitions exist throughout the text of the present disclosure.

[0049] Compositions and Methods of the Invention In one aspect, the present invention includes introducing a composition containing a cold slurry (e.g., ice slurry) directly into the interstitial tissue, i.e., not through the natural pathways in the body, such as arteries, veins, or the gastrointestinal tract, but directly into the tissue. When a predetermined volume of ice slurry is directly introduced into a predetermined volume of soft tissue, rapid heat exchange occurs between the tissue and the slurry. When injected rapidly locally, a pool of slurry is created that mixes with the targeted volume of local tissue. Symmetrically, when the slurry is injected more slowly into a larger volume, the slurry penetrates and flows through the spaces within the tissue, creating an extensive pathway filled with the slurry in a process similar to the administration of a tumescent anesthetic. The injection enables a continuous flow of the slurry through the tissue, particularly the tissue near the introduction site. The continuous or long-term flow of the slurry can cool the tissue to the same temperature as the slurry itself.

[0050] Generally, when injecting a slurry directly into tissue, there are two heat exchange periods: a rapid equilibration between the slurry and the local tissue, followed by a slow warming to body temperature. During the rapid equilibration, the slurry is warmed and the local tissue is cooled until an equilibrium temperature between the initial temperatures of the slurry and the tissue is reached. During this rapid tissue cooling by heat exchange, three events occur. 1) Heat stored by the heat capacities of the slurry and the tissue is exchanged. 2) Heat released by crystallization of the lipids in the tissue is exchanged. 3) Heat absorbed by melting of the ice in the slurry is exchanged. Depending on the parameters of the tissue and the slurry, some or all of the ice in the slurry melts and some or all of the lipids in the tissue crystallize. Crystallization of the lipids within the myelin sheaths of nerves, or direct cooling of unmyelinated nerves, results in targeted pain relief.

[0051] After rapid heat exchange with the slurry, it is gradually warmed by heat exchange with the body. Gradual warming occurs by a combination of heat diffusion from the surrounding warm tissue and convective heating from the blood flow. The blood flow can be decreased locally in the tissue by pressure or by drugs. For example, the blood flow can be stopped or significantly reduced by applying pressure to the cold tissue or by adding epinephrine or other vasoconstrictive drugs to the slurry. The desired level of pain relief will vary depending on the temperature, rate of cooling, duration of cooling, and number of cooling cycles.

[0052] The effectiveness of the treatment is related to the amount of lipid crystallization, the amount and number of epidermal nerve fibers, the reduction of myelinated nerve fibers in the dermis, the minimum temperature achieved, the duration of cold temperature, and the number of cold cycles (slurry injection can be easily repeated in one treatment session). All of these parameters can be controlled in the local tissue volume by varying the amount and rate of introduction of the slurry, including some with various ice contents.

[0053] I. Formulations Predictable cooling of the target tissue will be achieved by selection of the slurry element containing the liquid, the content of the cooled particles (e.g., ice content), and the application parameters (including position, velocity, volume of injection). During melting of the ice element of the slurry, the temperature of the slurry is at or near the melting point, and the slurry is kept cold during or after injection into the tissue. Depending on the composition and mass osmolality of its liquid component, this melting temperature can be selected to provide a desired effect on the tissue and may be from about -30°C to about 10°C, particularly from about -30°C to about 4°C, and more particularly from about -30°C to about 2°C.

[0054] The temperature of the solution containing the slurry can be adjusted by selection of the liquid phase components containing various solvents, solutes and ions that cause a controlled depression of the freezing point (e.g., including aqueous solutions of NaCl and other biocompatible salts, other electrolytes such as potassium or chlorine, glycerol, sugars, polysaccharides, lipids, surfactants, antimetabolites and detergents).

[0055] The solution containing the slurry may contain or may consist essentially of a lactated Ringer's solution or a saline aqueous solution or a hetastarch solution. A slurry formulation can be produced using dextrose, mannitol, glucose, sorbitol, mannitol, hetastarch, sucrose, glycerol or ethanol or polyvinyl alcohol. A depression of the freezing point up to about -40°C may be achieved using saline, glycerol, glucose, sorbitol, or mixtures thereof. In a specific embodiment, a slurry formulation may be produced using from about 0.1% to about 5% ethanol or from about 0.1% to about 20% glycerol (e.g., particularly from about 5% to about 10% glycerol).

[0056] In a specific embodiment, the solution containing the slurry is a lactated Ringer's solution containing from about 0.1% to about 20% glucose or glycerol, or not containing it; a physiological saline solution containing from about 0.1% to about 20% dextrose or glycerol, or not containing it; or a lactated Ringer's solution in 6% hetastarch. In another specific embodiment, the solution containing the slurry may contain from about 0.1% to about 6% hetastarch in a lactate electrolyte solution.

[0057] Glycerol is desirable for cryoprotection and / or use as a surfactant. The depression of the freezing point of a glycerol - aqueous solution can be achieved as described in Table 1 below.

Table 1

[0058] Ions that can be included in the slurry to obtain a controlled freezing point depression include, but are not limited to, calcium, potassium, hydrogen, chlorine, magnesium, sodium, lactate, phosphate, zinc, sulfur, nitrate ions, ammonium, carbonate ions, hydroxide ions, iron, barium, or combinations thereof, and salts made from these.

[0059] Local blood flow is an important factor. For example, if a long treatment time is desired, drugs that limit or eliminate local blood flow may be used. The solution containing the slurry may contain a vasoconstrictor that reduces local tissue blood flow. Suitable vasoconstrictors include, but are not limited to, epinephrine (e.g., 1 / 10,000 or less) and norepinephrine. Blood flow can also be reduced by using a tourniquet, applying pressure / compression, or suction in the treatment area. Vasoconstriction can also be achieved by pre - cooling the tissue to be treated by applying local cooling in the form of Peltier cooling, or by applying ice or cold packs to the skin surface.

[0060] The addition of physiologically compatible surfactant molecules can enhance the effects of fluid and tissue. The surfactant can also act as a foaming agent. Suitable surfactant molecules include, but are not limited to, sodium tetradecyl sulfate, polysorbate, polysorbate 20 (polyoxyethylene (20) sorbitan monolaurate), polyoxyethylene sorbitan monooleate, sorbitan monooleate polyoxyethylene sorbitan monolaurate, lecithin, and polyoxyethylene-polyoxypropylene copolymer, polysorbate, polysorbate 20 (polyoxyethylene (20) sorbitan monolaurate), polysorbate 40 (polyoxyethylene (20) sorbitan monopalmitate), polysorbate 60 (polyoxyethylene (20) sorbitan monostearate), polysorbate 80 (polyoxyethylene (20) sorbitan monooleate), sorbitan ester, poloxamer, or combinations thereof.

[0061] The addition of agents such as lysophosphatidylcholine, deoxycholate or other surfactants or detergents to the slurry may be able to target unmyelinated nerves. For example, lysophosphatidylcholine is known to cause reversible degeneration of unmyelinated axons (Mitchell J. Degeneration of Nonmyelinated Axons in the Rat Sciatic Nerve Following Lysolecithin Injection. Acta Neuropathol (Berl) (1982) 56:187-193). This combination can target myelinated and unmyelinated nerve fibers by slurry injection, so that the nerves can be completely blocked.

[0062] Accordingly, the solution containing the slurry may contain a cryoprotectant or a detergent that can function as a myelin-dissolving agent. Such detergents include, but are not limited to, TWEEN® polysorbate, deoxycholate, cholate, phosphatidylcholine and sodium deoxycholate. An exemplary slurry formulation is shown in Table 2.

Table 2

[0063] The solution containing the slurry may contain agents for reducing inflammation, including but not limited to corticosteroids, glucocorticoids, lipoxygenase inhibitors, and NSAIDs.

[0064] The solution containing the slurry may contain anesthetic agents for further reducing pain, and the anesthetic agents include but are not limited to polidocanol, lidocaine, bupivacaine, prilocaine, tetracaine, procaine, mepivacaine, and etidocaine.

[0065] In one embodiment, the anesthetic agent is QX-314, an N-ethyl bromide, a permanently charged molecule that can provide long-term (more than 24 hours) anesthesia, a quaternary lidocaine derivative. Unlike lidocaine, QX-314 can block nociceptors more selectively, has a longer duration of action, and fewer side effects. QX-314 is a charged molecule that needs to enter the cell and block sodium channels intracellularly. The ability of QX-314 to block from the inside rather than the outside of the nerve membrane could be utilized to block only the desired neurons. Combining QX-314 with the cold slurry injection described herein can selectively target nociceptive sensory neurons that sense cold and warm, and provide a selective and long-lasting anesthetic agent.

[0066] In another specific embodiment, the slurry may be composed of a lipid emulsion (e.g., Intralipid), an emulsion of soybean oil, egg phospholipid, and glycerin, and those with concentrations of 10%, 20%, and 30% are available. The lipid emulsion may be mixed with amino acids and dextrose as part of a total nutrient mixture.

[0067] In another specific embodiment, the slurry may be composed of a peritoneal dialysis solution.

[0068] The solution containing the slurry may contain cooled particles, for example, ice particles having a size smaller than the inner diameters of medical cannulas, catheters, and needles, for example, smaller than about 1 mm, preferably smaller than about 0.1 mm. The volume percentage, size, and / or shape of the cooled particles (preferably less than about 0.5 mm, nominally spherical or ellipsoidal) can be adjusted to optimize the flow of the slurry through the needle, catheter, or cannula and to be able to flow through various target tissues during injection. See, for example, Kauffeld, M et al., Int J Refrig. 2010. 33(8):1491 - 1505. The volume percentage of the cooled particles (e.g., ice particles) in the injected slurry and the volume of the injected slurry determine the cooling capacity of the injection. In a specific embodiment, the volume percentage of ice in the injected slurry may range from about 0.1% to about 50% of the solution.

[0069] II. Treatment Method In a given volume of target tissue into which the slurry is injected, there is a three - stage heat exchange. First, when the slurry is injected into and / or through the tissue, the slurry is considerably colder than the tissue. There is a strong thermal gradient between the tissue and the slurry, and it equilibrates rapidly until a local equilibrium temperature is achieved. During this rapid equilibration stage, the ice in the slurry melts. The amount of melting that occurs varies depending on the initial ice content, the local volume fraction of the slurry mixed with the tissue, the initial temperature of the tissue, the lipid content of the tissue, and other factors including the injection volume and rate of the slurry. These factors can be modeled using conventional many - fluid and heat - exchange approximations (e.g., using a finite - element model) (see Example 1). If ice remains after this initial equilibration time, the equilibrium temperature will be very close to the melting point of the ice in the slurry. That is, it may be from about - 20°C to about 4°C. The composition of the slurry liquid component sets a low - temperature boundary for this equilibrium temperature. That is, the equilibration temperature should not be lower than the depressed melting point of the ice in the slurry.

[0070] After reaching a local equilibrium, a second stage begins, and the ice continues to melt when heat is removed from the surrounding tissue. This second stage may last from seconds to minutes, depending on many factors. These factors include the amount of ice per unit volume remaining after the initial equilibrium, the dimensions of the volume of tissue containing the ice, the heat transfer and composition of the target and surrounding tissue, and the local blood flow. The second stage can be considered to provide the "treatment temperature and treatment time" to the target tissue because the temperature remains relatively stable in the target tissue until all the ice in the slurry has melted during this stage. The treatment temperature is mainly set by the composition of the slurry liquid and the volume fraction of the slurry injected into and around the target tissue. The treatment time is mainly set by the ice content and the injection variables including volume, velocity, and distribution, as well as by the size and shape of the target tissue and the blood flow in the target tissue. For example, a higher ice content in the slurry results in a longer second stage, and the larger the volume fraction of the slurry injected (the ratio of the locally injected slurry to the target tissue and the injected slurry), the longer this second stage. The larger the dimensions of the injected slurry and the target tissue, the longer this stage, approximately proportional to the square of the dimensions. The blood flow in the target tissue will shorten the treatment time by accelerating the melting of the ice in the slurry. Heat transfer from the surrounding (non-slurry-filled) tissue and heat transfer by blood flow melt the ice in the slurry during this second stage.

[0071] In a specific embodiment, the biocompatible ice slurry has a first equilibrium temperature of about 4°C to about -30°C and / or a second equilibrium temperature of about 2°C to about -30°C. These equilibrium temperatures are achieved, for example, as follows. Using a slurry composition of hetastarch (500 ml), physiological saline (500 ml), and glycerol (100 ml) in a lactate electrolyte, a slurry temperature of -5°C can be obtained. When approximately 25 ml of the slurry composition is bolus injected into the tissue once at an initial temperature of 29°C, the temperature of the tissue can be rapidly lowered to -3.2°C and maintained below 0°C for about 10 to 15 minutes. Using a slurry composition of hetastarch in lactate electrolyte (500 ml), physiological saline (500 ml), and glycerol (50 ml), a slurry temperature of -2.1°C can be obtained. When using a 15-gauge needle and bolus injecting approximately 50 ml into the tissue once, a tissue temperature of about -2°C to -1.3°C is achieved. The temperature within the tissue can be maintained below 0°C for about 15 minutes. When the tissue temperature is about -0.1°C, a second bolus injection of 40 to 60 ml of the slurry further lowers the tissue temperature to about -1.1°C and maintains this temperature for longer than 15 minutes. A third bolus injection enables the tissue temperature to be maintained below 0°C for longer than 20 minutes. By injecting the slurry composition about 4 to 5 times, it is possible to maintain the cold temperature below 0°C for 60 minutes to achieve sensory anesthesia. When the peripheral nerve is at a temperature below 0°C for about 60 minutes, sensory anesthesia occurs over several weeks (e.g., 6 to 8 weeks). Performing this multiple-cycle slurry injection can extend the cooling effect of the slurry injection.

[0072] The melting rate of ice can be monitored for a given application and anatomical situation. For example, ice can be readily visualized by medical ultrasound imaging, and this can be used to monitor the ice content, size and shape, and the melting rate of ice from the target tissue. In some applications, the ice content in the treatment tissue can be monitored using ultrasound during and after slurry injection. During the second stage, the treatment can be significantly lengthened by repeatedly injecting or continuously injecting the slurry. Using ultrasound guidance, the ice content can be monitored and thereby the repeated or continuous injection of the slurry can be adjusted.

[0073] To target the desired nerve, the position of the slurry placement can be monitored using ultrasound. For example, during injection of the slurry, the target nerve can be monitored using ultrasound to ensure that the slurry is placed correctly. This enables accurate delivery of the slurry and targeting of the desired nerve.

[0074] If it is desirable to lengthen the treatment time, methods to temporarily limit or eliminate local blood flow may be used. For example, mechanical forces can be applied to limit blood flow, including simply applying pressure after slurry injection, or, where appropriate, applying a tourniquet before, during, or after slurry injection. Cooling the tissue prior to slurry injection can also induce vasoconstriction. Using continuous external cooling after slurry injection can lengthen the effective duration of the slurry within the tissue.

[0075] The method of the present invention reversibly inhibits peripheral nerves. After administration of the slurry, inhibition can last up to about 5 months. For example, inhibition of the peripheral nerves can be achieved for several minutes, days, weeks, or months after a single administration of the slurry. By administering multiple cycles of the slurry, the treatment can be lengthened if necessary. Before slurry injection, the tissue can also be pre-cooled or cooled in advance and kept cold for an extended period of time.

[0076] The third stage after slurry injection occurs after the ice contents have melted. Here, the temperature of the target tissue can be gradually returned to body temperature by the same processes (heat conduction, heat convection by blood flow) that melted the ice during the second stage. Again, depending on size, anatomy, and the blood flow involved, it may take several minutes or hours for the target tissue to return to normal body temperature. Since all the ice in the slurry melts, the temperature within the target tissue rises during the third stage. These stages are schematically illustrated in FIG. 2.

[0077] Lipid crystallization is one mechanism for temporarily abolishing nerve conduction over a long period after cooling the nerve. The myelin sheath surrounding the axon contains a high concentration of lipids. The main mechanism of the lipid-rich sheath is to isolate the axon, as a result of which action potentials (i.e., nerve signals) can be propagated. The destruction and / or disappearance of the myelin sheath after local cooling seems to follow a similar mechanism, with stress and denaturation occurring after the myelin lipids have crystallized. Myelin is an extension of the cytoplasm of Schwann cells, and this type of damage repairs slowly. Therefore, long-term (up to about three months or more) reduction of anesthesia, pain, or itching is an application of the present invention. For example, slurries may be used for long-term nerve blocks after injection / infusion at many anatomical sites conventionally used for temporary nerve blocks using anesthetic injections.

[0078] The method of the present invention can reduce pain or itching, or eliminate neuropathies such as, for example, neuropathic pain, pain of diabetic neuropathy, trigeminal neuralgia, post-herpetic neuralgia, phantom limb pain, itching or pain associated with cancer, itching or pain of burns, lichen sclerosus et atrophicus, scalp itching, dysesthetic low back pain, atopic dermatitis, eczema, psoriasis, lichen planus, vulvar itching, vulvodynia, chronic simple lichen, prurigo nodularis, itching mediated by sensory nerves, peripheral neuropathy, peripheral nerve injury, pain after thoracotomy, incision pain, chest pain, coccydynia, low back pain (with or without radiculopathy), scars, neuromas, acute postoperative pain, lumbar facet joint syndrome, and cutaneous pain disorders.

[0079] Skin pain disorders include, but are not limited to, reflex sympathetic dystrophy (RSD), phantom limb pain, neuralgia, post-herpetic neuralgia, headache, occipital neuralgia, tension headache, and vulvodynia.

[0080] Using the method of the present invention, it is also possible to reduce or eliminate pain disorders caused by peripheral neuropathy, symptoms associated with damage to peripheral nerves from metabolic, infectious, traumatic, genetic, or chemical processes. Using the method of the present invention, it is also possible to reduce or eliminate skin pain.

[0081] Using the method of the present invention, it is also possible to reduce or eliminate symptoms associated with pain disorders caused by surgery (e.g., surgery that makes an incision through the skin and induces pain). This includes postoperative pain of the chest wall caused by chest wall surgery (e.g., treatment of pain by incision surgery). The slurry may be injected before, during, or after the incision.

[0082] In a specific embodiment, after chest wall surgery, about 3 cm 3 of the slurry may be used for pain inhibition by injecting it into the space under the rib. The exemplary lipid content of the subcostal nerve is about 20% (f tlip = 0.2). Before injection, an ice pack is applied to cool the local tissue to 20 °C (T t = 20). A slurry containing 30% ice (I o = 0.3) and 0.001% epinephrine is added for vasoconstriction and injected around the nerve so that approximately the same volume of slurry and tissue is created (f s = 0.5). After a rapid exchange based on heat capacity, the temperature of the slurry-tissue mixture is T m = (1 - f s )T = 10 °C. Since T m = 10 °C, no new ice melts to reach 10 °C, i.e., Q to10C = (T m-10) ρC = 0. The latent heat is exchanged as ice in the melt of the slurry-tissue mixture, while the lipid crystallizes in the myelin sheath of the target nerve. The initial ice content of the slurry-tissue mixture is I o = f s I s where I o = (0.5)(0.3) = 0.15% or 15%. At this ice content, the value of Q icetotal = f s I s H ice or (0.5)(0.3)(74) = 11 cal / cm 3 The lipid content of the slurry-tissue mixture is f inlip = (1 - f s ) f tliP where (0.5)(0.2) = 0.10 or 10%. In the slurry-tissue mixture, due to the crystallization of all lipids (exothermic process), as described above, the heat energy Q lipid is equal to the product of the lipid content and the heat of fusion H liptotal multiplied by the volume of the lipid. Using the lipid content f mlip = 0.1 and the value of H lipid = 34 cal / cm 3 , the energy associated with lipid crystallization in the target nerve is Q liptotal = f mlip H lipid = (0.1)(34) = 3.4 cal / cm 3 Since Q icetotal > Q liptotal , all the lipids in the nerve crystallize and the remaining ice remains. When this remaining ice melts, the temperature decreases according to the value of Q iceresidual = Q icetotal - Q liptotal and the value of Q iceresidual = 11 - 3.4 = 7.6 cal / cm 3 is obtained. The final temperature is given by T final ~ 10 - Q iceresidual / ρC. As described above, the value of ρC for most soft tissues is close to 1 cal / °C-cm 3 and as a result, T final ~ 10 - 7.6, that is, 2.4 °C. Then, about 6 cm3 The slurry-tissue mixture of volume is gradually heated. The diameter of the sphere of volume v is d = (6v / π)^(1 / 3). 1 / 3 is given by. Thus, for a slurry-tissue mixture of spherical volume of 6 cm 3 the diameter is approximately 22 mm. The cold slurry-tissue mixture is gradually heated over approximately (22)^(1 / 3) = 480 seconds, i.e., about 8 minutes. A second or further injection of the slurry may also be performed, and the effectiveness of multiple cooling cycles is typically greater than that of a single cycle. 2 Using the method of the present invention, it is also possible to reduce muscle spasms caused by abnormal nerve firing such as bladder spasms or facial spasms.

[0083]

[0084] The method of the present invention can also target motor nerves when long-term paralysis of motor nerves is desired.

[0085] Using the method of the present invention, it is also possible to reduce, eliminate, or alter functions controlled by the autonomic nervous system. For example, the sympathetic nervous system controls sweating by sympathetic fibers that stimulate eccrine glands in the armpits. The method of the present invention can be used to target autonomic fibers to reduce sweating.

[0086] The slurry-containing solution may be administered to the peripheral nerves of a subject by injection, infusion, or tumescent pumping of the slurry into one or more nerves selected from the group consisting of the nerves of the skin, trigeminal nerve, ilioinguinal nerve, intercostal nerve, interscalene nerve, supraclavicular nerve, subclavian nerve, axillary nerve, pudendal nerve, paravertebral nerve, nerves on the fascial plane of the transverse abdominal muscle, lumbar plexus, femoral nerve, and sciatic nerve, such as one or more peripheral, subcutaneous, or autonomic nerves of the subject.

[0087] ​The method of the present invention can reduce or eliminate pain associated with plexuses (i.e., groups of intersecting nerves), including, but not limited to, the cervical plexus that bears the head, neck, and shoulders; the brachial plexus that bears the chest, shoulders, arms, and hands; the lumbar plexus that bears the back, abdomen, groin, thighs, knees, and calves; the sacral plexus that bears the pelvis, buttocks, genitals, thighs, calves, and feet; the celiac plexus (solar plexus) that bears the viscera; the coccygeal plexus that bears a small area above the coccyx; the Auerbach plexus that bears the gastrointestinal tract; and the Meissner plexus (submucosal plexus) that bears the gastrointestinal tract.

[0088] The method of the present invention can also be used in renal sympathetic denervation, which is a treatment that emerged to treat severe and / or resistant hypertension.

[0089] When the slurry is flowed through the tissue, it can be cooled over a large distance from the injection point, particularly through tissue structures with minimal resistance to fluid flow, such as along the perineural sheath of sensory or motor nerves. This solution can also be administered percutaneously by a syringe needle or to any peripheral or subcutaneous nerve accessible by a catheter through the circulatory system.

[0090] The means for injecting the slurry (e.g., a needle) may be provided with additional features (e.g., a sensor capable of reading the temperature and monitoring the temperature of the target tissue). The means for injecting the slurry may optionally have the ability to recover the melted components of the slurry while allowing the injection of fresh slurry, as shown in FIG. 17.

[0091] The injection site can be confirmed, for example, by MRI or x-ray imaging if the slurry contains an imaging agent known in the art. Pre-activation of the nerve by electrical or chemical stimulation and / or confirmation of the needle position can also be performed in combination with the method of the present invention. Here, the correct placement of the slurry can be facilitated by injecting an anesthetic or electrical stimulus to create a sensation or anesthesia along the target nerve before injecting the slurry.

[0092] The duration for which the slurry is administered is determined by a physician or other skilled expert or technician and can be adjusted, if necessary, to suit the observed effect of the treatment or, if necessary, depending on the formulation of the slurry being administered. Adjusting the duration of treatment according to the methods described herein is well within the common general knowledge of a person skilled in the art.

[0093] The method of the present invention can also be used to treat urinary incontinence. In recent surveys of women aged 25 - 84 in the United States, approximately 15% were reported to experience stress incontinence and 13% were reported to experience urge incontinence / "overactive bladder". The causal relationships of these two types of incontinence are due to separate mechanisms, but both mechanisms may be experienced by a single patient.

[0094] Stress incontinence is the most common type of incontinence in young women and is often due to hypermobility of the urethra, resulting from inadequate bladder support from the pelvic floor. This lack of support is due to the loss of connective tissue. This lack of support is also associated with other conditions such as, for example, pelvic organ prolapse and bowel problems (both constipation and incontinence). At present, the main treatment strategies include pharmacological treatment, pessary, and surgical intervention, and the success rates vary. The parasympathetic, sympathetic, and somatic nerves play important roles in controlling lower urinary tract function. More specifically, the smooth muscle of the bladder (detrusor muscle) is mainly stimulated by the parasympathetic nerves. The smooth muscle of the bladder neck and urethra (internal sphincter) is stimulated by the sympathetic nerves. The striated muscle of the external urethral sphincter (EUS) receives the main stimulation from the somatic nerves. The slurries described herein could be used as an injectable treatment for treating stress incontinence while targeting one or more of these nerves.

[0095] Urge incontinence is due to overactivity of the detrusor muscle. Treatments for treating urge incontinence are mainly pharmacological (e.g., botulinum toxin) and target reducing the neural input to the bladder muscles to prevent frequent bladder spasms. From the ability of the ice slurries described herein to reduce neural function, another embodiment of the invention provides a treatment for urge incontinence by inhibiting the neural input to the bladder. In one embodiment, the treatment includes an injectable treatment such that the ice slurry is administered, for example, at the neuromuscular junction to inhibit the neural input to the bladder.

[0096] The present invention is further described by the following non-limiting examples, which serve to provide a better understanding of the present invention and its many advantages.

Examples

[0097] The following examples illustrate some embodiments and aspects of the present invention. Various modifications, additions, substitutions, etc. can be made without changing the spirit or scope of the present invention, and it will be apparent to those skilled in the art that such modifications and variations are included within the scope of the present invention as defined in the following claims. The following examples do not limit the present invention in any way.

[0098] Example 1: Quantitative Model to Show the Behavior of the Injected Slurry A simplified reasonable estimate is made in a quantitative model to show the behavior of the injected slurry, as shown in FIG. 1.

[0099] The heat capacity is an important factor in the heat exchange between the slurry and the tissue. The first heat exchange to consider is the heat exchange of the energy stored by the heat capacities of the slurry and the tissue. The energy per unit volume in the medium stored by the heat capacity is given by H = TρC, where H is the energy density (cal / cm 3 ) and T is the temperature (°C), p is the density (gm / cm 3 ) and C is the specific heat capacity (cal / °C gm). It is assumed that ρC is the same for the slurry, tissue, and water (i.e., ρC = 1 cal / gm-°C). This assumption is approximately correct for all soft tissues except fat. In the case of fat, ρC is about half as small.

[0100] Consider the local volume of the tissue into which the slurry is introduced. If the slurry is introduced into the local tissue at a volume fraction f s , this local tissue occupies a volume fraction of (1 - f s ). Due to the heat capacity of the slurry, the heat stored per unit volume of the resulting slurry-tissue mixture is H s = f s T s ρC, and the heat stored per unit volume due to the heat capacity of the tissue is H t = (1 - f s ) T t ρC. After the rapid exchange of thermal energy due to the heat capacity, the new temperature T mis achieved. The thermal energy due to the heat capacity of this mixture is H m = T m given by ρC. Conservation of energy in local heat exchange requires that H s + H t = H m . Combining this equation gives f s T s ρC + (1 - f s ) T t ρC = T m ρC T m . Solving for T, the temperature of the slurry - tissue mixture after this initial part of the heat exchange is T m = f s T s + (1 - f s ) T t . Since the temperature of the physiological ice slurry is near 0, this simplifies to T m = (1 - f s ) T t . The rapid heat exchange during mixing due only to heat capacity is the average weighted by the volumes of the two starting temperatures. For example, if f s = 0, no slurry is added and T m = T t , which is the starting temperature of the tissue. If f s = 1, the mixture is all slurry and Tm = 0. If f s = 0.5, it is a 50 - 50 mixture of slurry and tissue and the temperature obtained after mixing is the average of the starting temperatures of the slurry and the tissue. Typical values of f s for interstitial injection of slurry are in the range of about 0.2 to about 0.8, i.e., the volume of the mixed slurry - tissue may have a slurry content of about 20% to about 80%. Also, consider the case where f s = 0.5. If the starting tissue temperature T t is 37°C, after heat exchange from the heat capacity, Tm = 18.5°C.

[0101] Define the volume fraction of ice in the physiological slurry in this model as I s which is the volume of ice per unit volume of the slurry. Thus, immediately after injection into the tissue, the initial volume fraction of ice in the local slurry-tissue mixture is I o =f s I s where I o is the total amount of ice available for melting per unit volume of the slurry-tissue mixture.

[0102] After rapid heat exchange from the heat capacity, the ice in the slurry component of the slurry-tissue mixture begins to melt, absorbing heat and cooling the slurry-tissue mixture. Before the period of gradual warming by the in-vivo heat exchange briefly described above, the ice in the slurry-tissue mixture melts until it disappears or until it reaches the equilibrium temperature. In pure water, ice and liquid water may coexist at the equilibrium temperature of 0 °C to 4 °C. In tissues, there are many solutes that lower the freezing point, and as a result, ice and water may coexist over a certain low temperature range (e.g., about -8 °C to 0 °C in the skin). Lipids in tissues are in a liquid state at normal body temperature. When cooling of the slurry-tissue mixture occurs due to the melting of ice, lipids may crystallize below a certain temperature. Essentially, there is heat exchange between the latent heat of fusion from the melting ice and the latent heat of fusion from the crystallization of lipids. Since lipid crystallization occurs at a temperature much higher than the freezing point of water, these two processes proceed in opposite directions (e.g., water melts and lipids crystallize). Most animal fats crystallize at 10 °C to 15 °C, depending on the length and degree of saturation of the lipid chains in the triglyceride molecules. Wax esters and free fatty acids crystallize at similar temperatures. Polar lipids crystallize at lower temperatures. For example, the phospholipids in cell membranes can remain fluid to a sufficient extent even below 0 °C.

[0103] The physiological slurry injected is effective in suppressing pain or itching by affecting the myelin sheath lipids of nerves. The lipids of the sheath crystallize sufficiently even above 0 °C. Effective treatment is at the starting tissue temperature Tt , the ice content I of the slurry s , a sufficient slurry fraction f in the slurry-tissue mixture s The amount and rate of the slurry injected to achieve, and the target lipid content L of the tissue t , its crystallization temperature T c , varies depending on variables including the time that some ice remains in the slurry-tissue mixture.

[0104] The enthalpy of fusion (also called the heat of fusion) describes how much thermal energy is absorbed (endothermic) or released (exothermic) due to the change from the solid state to the liquid state. The melting of ice is an endothermic transition that requires a large amount of thermal energy. In the case of water, the heat of fusion is 80 cal / gm. The density of ice at 0 °C is 0.92, and as a result, the volumetric heat of fusion H ice (the thermal energy required to melt a given volume of ice) is H ice = 74 cal / cm 3 is. The total heat Q per unit volume that can be absorbed by melting all the ice in the slurry-tissue mixture icetotal is simply the product of its ice content and H ice , and Q icetotal = f s I s H ice is.

[0105] f s Typical values as described above for f are in the range of about 0.2 - 0.8, and the ice content of physiological slurries can be up to about 50% (I s ~ 0.5). Thus, for a suitable maximum I s = 0.5, the range (without limitation) of Q in the slurry-tissue mixture is about 7 - 30 cal / cm icetotal is. 3

[0106] The heat of fusion of lipids in animal fat is in the range of about 30 - 50 cal / gm (Cooling​ Technology in the Food Industry; Taylor and Francis, 1976). The density of lipids ranges from about 0.8 to 0.9 g / cm 3 (for example, solid palmitic acid triglyceride is 0.85 g / cm 3 ). Taking an average value of 40 cal / gm as the heat of fusion, the latent heat per unit volume for lipid crystallization is approximately H lipid = 34 cal / cm 3 .

[0107] Therefore, the latent heat for lipid crystallization is less than half of the latent heat for melting ice. Cooling of the slurry-tissue mixture proceeds to some extent by melting of some ice until the temperature reaches about 10 °C, which is the temperature required for lipid crystallization to begin. The thermal energy consumed by lowering the temperature of the slurry-tissue mixture to about 10 °C is Q to10C = (T m - 10)ρC .

[0108] At approximately this temperature, any ice remaining from the slurry melts and absorbs the energy required to crystallize approximately twice the volume of the lipid itself. If all the lipids in the tissue crystallize, more ice melts and the temperature drops below about 10 °C, potentially down to about -8 °C to 0 °C where ice and liquid water can coexist in the tissue. Therefore, the lipid content of the slurry-tissue mixture is another important factor. Defining the lipid content of the tissue as f tlip , the lipid content of the slurry-tissue mixture is f mlip = (1 - f s )f tlip .

[0109] f tlip The value of varies depending on the type of tissue. The lipid content of most soft tissues ranges from about 5% (most connective tissues) to about 80% (fat), i.e., ftlip is 0.05 to 0.8. The energy per unit volume of the slurry-tissue mixture created by crystallization of all the lipids present is Q liptotal = f mlip H lipid .

[0110] During the latent heat exchange time between melting of ice and crystallization of lipids in the slurry-tissue mixture, the ice in the slurry melts until all the lipids have crystallized or until the ice is gone.

[0111] The fraction of lipids crystallizing in the slurry-tissue mixture is simply given by the energy balance, f lipxtal = (Q icetotal - Q to10C ) / Q liptotal . (Q icetotal - Q to10C ) < Q liptotal , some of the lipids crystallize and f lipxtal is given above. (Q icetotal - Q to10C ) = Q liptotal , all of the lipids crystallize and all of the ice melts and the temperature remains near about 10°C which is the phase transition temperature of most animal lipids. (Q icetotal - Q to10C ) > Q liptotal , all of the lipids crystallize and then the temperature drops to below about 10°C (i.e., to the temperature range of about -8°C to 0°C) until all of the ice has melted or until an equilibrium exists between the ice and liquid water in the tissue. The lowest temperature reached is determined by the heat exchange between melting of the remaining ice and the heat capacity of the slurry-tissue mixture. Thus, the lowest temperature T final will be estimated by equating the latent heat per unit volume absorbed by melting the remaining ice and the heat associated with the heat capacity of the temperature drop below about 10°C.

[0112] The latent heat associated with melting of the ice remaining after the lipids have crystallized is Q iceresidual=Q icetotal -Q to10C -Q liptotal and the amount of ice remaining per unit volume is I residual =Q iceresidual =H ice is. The temperature drop to T due to the melting of the remaining ice final can be estimated by Q iceresidual ~(10 - T final )ρC and rearranged to T final ~10 - Q iceresidual / ρC.

[0113] The above modeled local heat exchange occurs on a time scale of seconds because the slurry is in intimate contact with the tissue as it mixes and flows through the soft tissue and / or cuts during interstitial injection. After the exchange of latent heat from the melting ice and crystallizing lipids, the temperature of the slurry - tissue mixture is fixed at approximately T final and then gradually heated due to conduction and convection. Therefore, the rate of gradual heating varies depending on the rates of conduction and convection. In the absence of blood flow (convection), heating by conduction includes a minimum characteristic time that is proportional to the square of the diameter of the local slurry - tissue mixture. Typically, in soft tissue, the time in seconds to substantially heat a region by conduction (to 1 / e of the final equilibrium value) is approximately equal to the square of the diameter in millimeters. For example, a slurry - tissue mixture with a diameter of 10 mm typically requires about 100 seconds to substantially heat, and a slurry - tissue mixture with a diameter of 30 mm typically requires about 900 seconds (i.e., 15 minutes) to substantially heat by conduction. Depending on the ice content, some ice may remain even after this estimated period of substantial heating. The model presented here is for illustrative purposes and not actual. Direct measurements of the temperature of the slurry and tissue can be made. As shown below, such measurements generally agree with this appropriate model.

[0114] Example 2: Inhibition of Sciatic Nerve Function in Rats A 6% hetastarch lactated Ringer's slurry (i.e., a blend of hetastarch (500 ml), saline (500 ml), and glycerol (50 ml)) was injected above the sciatic nerve of male rats weighing approximately 250 - 271 g. This procedure was carried out as follows. The rats were placed under general anesthesia conditions using inhaled isoflurane and oxygen. The sciatic nerve was exposed by surgical incision (Figure 3). A slurry with an initial temperature of -3.2°C to -2.7°C was obtained and maintained throughout the experiment. For each of the 5 injections, 5 ml of the slurry was injected above the sciatic nerve. A thermocouple placed under the sciatic nerve was used to record the tissue temperature (Figure 4).

[0115] The 6% hetastarch lactated Ringer's slurry was able to maintain the temperature of the nerve tissue below 0°C for an average of 5 minutes, and the tissue temperature was maintained as long as ice was present in the slurry (Figures 5, 6, and 7). Nerve blocks are predicted to last for days, weeks, or months. When the ice melted into liquid, the tissue temperature immediately rose above 0°C. Cooling the tissue around the nerve in advance caused the ice to melt at a slower rate, so the slurry lasted longer (Figure 6).

[0116] Example 3: Sensory Tests in Rats The efficacy of cryotherapy in large motor and sensory nerves (e.g., the sciatic nerve) can be demonstrated in a rodent model by performing an assay that evaluates the staining of nerve tissue and measures the motor and sensory functions after injection of the cold slurry. Sensory experiments were conducted in 12 male adult rats weighing 250 g - 350 g. The rats were acclimated to the test environment, labeled 1 - 12, and randomly divided into 2 groups of 6 rats each. A baseline sensory test was performed 1 day before the procedure.

[0117] All rats received a chronic constriction injury (CCI) to the chronic neuropathic pain model. Using blunt dissection throughout the biceps femoris muscle, the sciatic nerve was exposed and separated from adjacent tissues as shown in Figure 8. At two points approximately 1 mm apart from each other, 4-0 chromic gut sutures were loosely tied around the nerve. Depending on the desired degree of stenosis, the circulation by the superficial epineurial vasculature was slowed but not stopped.

[0118] Six days after CCI, the sensory test was repeated in rats to demonstrate the efficacy of this procedure, i.e., the rats had a higher sensitivity to heat-induced injury in the injured foot than in the uninjured foot, and when exposed to heat pain, the injured foot was withdrawn much more quickly. One week after CCI, the sciatic nerve was exposed in all rats using blunt dissection. Six rats received an injection of ice slurry as shown in Figure 9. Six rats were opened and closed (without slurry) without injecting the slurry.

[0119] The slurry injected into the six rats in the experimental group consisted of 5% glycerol (by weight) and 5% glycerol addition (by weight) in physiological saline before injection. 10 cc of slurry was injected around the sciatic nerve in each rat. A thermocouple was placed next to the nerve and the temperature was recorded. The average temperature of the slurry on the sciatic nerve during injection was approximately -1.1 °C. When the temperature reached +5 °C, the area was wiped with sterile gauze and another 10 cc of slurry was injected around the sciatic nerve again. The temperature of the tissue at the injection site reached +5 °C on average within about 5 minutes.

[0120] All rats were sufficiently tolerant of the slurry injection. No evidence of necrosis, infection, ulceration or self-injurious behavior was seen.

[0121] A sensory test was conducted to examine the potential analgesic effect of ice slurry at 14, 20, 25, 32, 36, and 42 days after slurry injection. All rats were randomly divided, but several rats responded well to chronic constriction injury because, as expected, their sensitivity to heat-induced pain became more excessive. These rats were used to evaluate the reduction of heat-induced pain by ice slurry injection. The results are shown in the figures described below.

[0122] Figure 10 shows the heat-induced hind paw withdrawal latency of responsive rats, indicating a longer response time to heat exposure in rats at 20, 25, and 42 days after slurry injection. A longer response time indicates less pain from heat stimulation, showing that the slurry reduces heat-induced pain.

[0123] Sensory tests in rats are known to vary, and one way to reduce this variation is to report the difference between the test side (left hind paw) and the internal control (right hind paw), i.e., the latency of the right hind paw - the latency of the left hind paw. Figure 11 shows the test results by comparing the difference in heat-induced withdrawal latency of responsive rats while normalizing to the internal control. A positive value indicates that the left paw is withdrawn earlier than the right paw in response to heat-induced pain. A decrease in the difference in latency between the left and right paws was seen after slurry injection, indicating that the slurry reduces heat-induced pain.

[0124] Experiment 4: Tolerance to Various Slurry Compositions The slurries listed in Table 3 were prepared and successfully injected around the rat sciatic nerve. "NS" is an abbreviation for "normal saline" (0.90% grams of NaCl per 1 ml of H2O). "Hetastarch" is another term for "hydroxyethyl starch" and is a non-ionic starch derivative. HEXTEND® (6% hetastarch in lactated electrolyte injection, with an average molecular weight of 670,000 daltons, available from Hospira, Inc., Lake Forest, Illinois) was used for the experiments conducted herein. "LR" is an abbreviation for lactated Ringer's solution. The ratio of glycerol is expressed in g / ml. [Table 3]

[0125] One week after injection, all rats were examined for tolerable side effects by observation, dissection of the injected area, and overall observation. All animals tolerated the injection without signs of infection, ulceration, necrosis, or side effects until one week after injection.

[0126] The following Table 4 shows the details of further safety and tolerance tests on rats. Tattoo ink was added to show the localization of the injected slurry around the sciatic nerve. [Table 4]

[0127] In none of the rats were there any signs of infection, tissue necrosis, or ulceration 24, 48, or 72 days after injection. The muscle remained intact overall. There was no difference in examination one week after injection between the side where the slurry was injected and the side where the slurry was not injected. The tattoo ink was found to be localized around the nerve, indicating that the slurry was accurately injected around the target tissue (Figure 13).

[0128] While increasing the amount of glycerol, injections were made around the sciatic nerve of rats, and further tests were conducted to examine the safety and tolerance limits of the cryogenic slurry. The rats were observed once a day until one week after the injection, and the tolerance to side effects was examined by observation, photography, and histology. The results are shown in Table 5.

Table 5

[0129] None of the animals showed signs of infection, ulceration, necrosis, or side effects until the animals were sacrificed one week after the injection and were tolerant to the injection. No abnormalities were noted upon examination.

[0130] Example 5: Relationship between Solute Concentration and Slurry Temperature In FIG. 12, the effect of increasing the glycerol concentration (in physiological saline) on the slurry temperature is shown. Increasing the amount of glycerol in the slurry significantly decreased the slurry temperature. The slurries shown in Table 5 were injected to test the safety and tolerance limits of the lowest tolerance slurry temperature. None of the animals showed signs of infection, ulceration, necrosis, or side effects until the animals were sacrificed one week after the injection and were tolerant to the injection. No abnormalities were noted upon examination.

[0131] Example 6: Feasibility of Invisible Cryoneurolysis Injection Referring now to FIG. 13, tattoo ink (black pigment) was added to a slurry composed of physiological saline and 20% glycerol. In Sprague-Dawley rats, this slurry was injected into an anatomical pocket containing the sciatic nerve. One week after the injection, the rats were sacrificed, and then the skin overlying the anatomical pocket containing the sciatic nerve was incised to confirm the placement of the slurry adjacent to the sciatic nerve (visible due to the tattoo ink). This image demonstrates the feasibility of delivering the slurry around the sciatic nerve by an invisible injection through the skin.

[0132] Example 7: Rat Sensory Tests Prior to obtaining baseline measurements, additional sensory tests were performed on Sprague-Dawley rats that had been housed in the sensory test environment for three consecutive days. A baseline sensory test by heat using the withdrawal latency period was performed. The heat-induced withdrawal latency period represents the amount of time it takes for the rat to withdraw its hind paw from an infrared heat source. A large value means a high pain threshold, and a small value means that the rat has an increased sensitivity to pain. All rats received a chronic constriction injury (CCI) for the chronic neuropathic pain model. A blunt incision was used over the entire biceps femoris muscle to expose the sciatic nerve and separate it from adjacent tissues. At two points approximately 1 mm apart from each other, a 4-0 chromic gut suture was loosely tied around the nerve. Depending on the desired degree of stenosis, the circulation by the superficial epineurial vascular system was slowed but not stopped. Six days after CCI, the sensory test was repeated in the rats to demonstrate the efficacy of this procedure. One week after CCI, the sciatic nerve was exposed in all rats using a blunt incision.

[0133] The slurry injected into the rats in the experimental group consisted of 10% glycerol (by weight) in saline, and the average temperature was -3.9 °C. A thermocouple was placed next to the nerve and the temperature was recorded. First, in each rat, 5 cc of the slurry was injected into the nerve. Then, a syringe smaller than the delivery syringe was used to continuously remove the slurry from the site and replace it with fresh ice slurry once it melted. A 15-minute nerve cooling duration was ensured, which was defined as a temperature of less than +5 °C at this site of the nerve. A sample of the slurry was removed from the container and warmed to room temperature. A room temperature solution having the same composition as the slurry was injected into the control (room temperature slurry) rats.

[0134] All rats were fully tolerant to the injection of the slurry. No evidence of necrosis, infection, ulceration, or self-injurious behavior was seen. Sensory tests were performed to examine the potential analgesic effect of the ice slurry at intermediate time points (5 and 6 days after slurry injection), and then at long-term time points (28 days after slurry injection). The selected rats were matched based on the mean injury severity after CCI. Injury severity was determined by the decrease in the heat withdrawal latency compared to the mean baseline measurement. Injury severity = (baseline heat withdrawal time) - (heat withdrawal time at time point X). Here, a reading of 0 indicates that the rat has returned to its baseline (pre-injury) pain threshold. Four rats were perfectly matched (difference less than 0.2 s), and then an additional two rats were matched at the highest severity of that group (difference less than 0.5 s).

[0135] In rats with severe sciatic nerve stenosis injury, the addition of ice slurry resulted in a decrease in the pain level to heat stimulation at 6 and 28 days after injection (Figure 14). Compared to rats injected with room temperature slurry (shown in red), rats injected with ice slurry (shown in blue) had a 4.4-fold decrease in the heat withdrawal latency at 28 days after slurry injection (1.4 s vs. 6.2 s), indicating a significant decrease in the sensitivity to heat pain.

[0136] In rats with moderate sciatic nerve stenosis injury, the addition of ice slurry resulted in a decrease in the pain level to heat stimulation at 6 and 28 days after injection (Figure 15). Compared to rats injected with room temperature slurry (shown in red), rats injected with ice slurry (shown in blue) had an almost 2-fold decrease in the heat withdrawal latency at 28 days after slurry injection (2.1 s vs. 4.1 s), indicating a significant decrease in the sensitivity to heat pain.

[0137] In rats with mild sciatic nerve stenosis injury, the addition of ice slurry reduced the pain level in response to heat stimulation 6 days and 28 days after injection (Figure 16). Compared to rats injected with room temperature slurry (shown in red), rats injected with ice slurry (shown in blue) had an 11-fold decrease in the heat withdrawal latency at 28 days after slurry injection (0.2 s vs. 2.2 s), indicating a significant decrease in heat-induced pain sensitivity. In fact, by 28 days, rats injected with ice slurry had heat sensitivity equivalent to the baseline level, meaning that the addition of ice slurry reduced the pain level to the baseline.

[0138] Example 8: Injection of Slurry around the Sciatic Nerve of Intact (Undefeated) Rats Male Sprague-Dawley rats weighing 250 - 271 g were obtained and baseline sensory tests were performed. The heat withdrawal latency of the hind paw was obtained. Then, using inhaled isoflurane and oxygen, the rats were anesthetized, the hair on their left thigh region was shaved and cleaned. Next, a slurry with the following composition shown in Table 6 was injected into the dissection pocket containing the left sciatic nerve.

Table 6

[0139] All rats were sufficiently tolerant of this procedure, and no adverse effects were observed at the injection site during follow-up. At 7, 14, and 25 days after slurry injection, the rats underwent subsequent sensory tests (Figure 18). Compared to the baseline, the heat withdrawal latency of the hind paw injected with slurry was prolonged at the follow-up at 7, 14, and 25 days after slurry injection. The prolonged heat latency reflects an increased tolerance to heat-induced pain and is an indicator of analgesia in the left hind paw. The difference in heat withdrawal latency between the left (injected with slurry) and right (not injected) is shown in Figure 19. The heat withdrawal latency of the left hind paw (receiving slurry injection) was prolonged, while the right remained relatively constant (no change).

[0140] From the foregoing, it will be apparent that variations and modifications may be made to the invention described herein to adapt it to various uses and conditions. Such embodiments are also within the scope of the following claims. The citation of an element in the recitation of a variable definition herein includes the definition of the variable as any one element or combination (or sub-combination) of the recited elements. The citation of an embodiment herein includes the embodiment as any one embodiment or in combination with any other embodiment or part thereof. Literature All patents, patent applications, and publications referred to herein are incorporated herein by reference to the same extent as if each individual patent and publication were specifically and individually indicated to be incorporated by reference. Those incorporated by reference include, but are not limited to, the following. 1. Lenz H, Goertz W, Preussler H. The freezing threshold of the peripheral motor nerve: an electrophysiological and light-microscopical study on the sciatic nerve of the rabbit. Cryobiology 1975;12:486-96. 2. Barnard D. The effects of extreme cold on sensory nerves. Ann R Coll Surg Engl 1980;62:180-7. 3. Kauffeld M, Wang MJ, Goldstein V, Kasza KE. Ice Slurry Applications. Int J Refrig 2010;33:1491-505. 4. Shikanov S, Wille M, Large M, et al. Microparticulate ice slurry for renal hypothermia: laparoscopic partial nephrectomy in a porcine model. Urology 2010;76:1012 - 6. 5. Vanden Hoek TL, Kasza KE, Beiser DG, et al. Induced hypothermia by central venous infusion: saline ice slurry versus chilled saline. Crit Care Med 2004;32:S425 - 31. 6. Garbay B, Heape AM, Sargueil F, Cassagne C. Myelin synthesis in the peripheral nervous system. Prog Neurobiol 2000;61:267 - 304. 7. Halkier - Sorensen, L. and K. Thestrup - Pedersen, The relevance of low skin temperature inhibiting histamine - induced itch to the location of contact urticarial symptoms in the fish processing industry. Contact dermatitis,1989.21(3):p.179 - 83. 8. Fruhstorfer, H., M. Hermanns, and L. Latzke, The effects of thermal stimulation on clinical and experimental itch. Pain,1986.24(2):p.259 - 69. 9. Pradel, W., et al., Cryosurgical treatment of genuine trigeminal neuralgia. Br J Oral Maxillofac Surg, 2002. 40(3): p. 244-7. 10. Calandria, L., Cryoanalgesia for post-herpetic neuralgia: a new treatment. Int J Dermatol. 2011. 50(6): p. 746-50. 11. Hargreaves K, Dubner R, Brown F, Flores C, Joris J(1988). A new and sensitive method for measuring thermal nociception in cutaneous hyperalgesia. Pain 32:77-88. 12. Mitchell J. Degeneration of Non-myelinated Axons in the Rat Sciatic Nerve Following Lysolecithin Injection. Acta Neuropathol (Berl)(1982) 56:187-193.

Claims

**Claim 1** A composition for use in reversibly inhibiting one or more peripheral nerves in a subject in need thereof, comprising a biocompatible ice slurry, wherein said reversible inhibition comprises accessing a tissue containing one or more peripheral nerves and administering said biocompatible ice slurry around said one or more peripheral nerves by injection, said biocompatible ice slurry being configured to cool said one or more peripheral nerves for a duration sufficient to inhibit said one or more peripheral nerves and said inhibition being reversible, a composition. **Claim 2** The composition according to claim 1, wherein the injection of the biocompatible ice slurry around the one or more peripheral nerves comprises delivering the biocompatible ice slurry along the perineural sheath of the one or more peripheral nerves. **Claim 3** The composition according to claim 1, wherein said one or more peripheral nerves are at least one of a subcutaneous nerve, an autonomic nerve, or a somatic nerve. **Claim 4** The composition according to claim 1, wherein said biocompatible ice slurry is configured to cool said one or more ablated nerves to a temperature sufficient to crystallize a plurality of lipids of the myelin sheath of said one or more peripheral nerves. **Claim 5** The composition according to claim 1, wherein said biocompatible ice slurry is configured to cool said one or more ablated nerves to a temperature of about 5°C to about -40°C. **Claim 6** The composition according to claim 1, wherein said biocompatible ice slurry is configured to have a first equilibrium temperature of about 4°C to about -30°C. **Claim 7** The composition according to claim 6, wherein said biocompatible ice slurry is configured to have a second equilibrium temperature of about 2°C to about -30°C. **Claim 8** The composition according to claim 1, wherein said duration sufficient to inhibit said one or more peripheral nerves in a subject is at least about 5 minutes. **Claim 9** The composition according to claim 1, wherein said biocompatible ice slurry comprises a plurality of ice crystals. **Claim 10** Said biocompatible ice slurry is configured to cool said one or more ablated nerves by tissue cooling, said tissue cooling comprising (i) exchanging heat stored by the heat capacities of said biocompatible ice slurry and the tissue, (ii) exchanging heat released by crystallization of one or more lipids of said tissue or one or more lipids of the myelin sheath of said one or more ablated nerves, and (iii) exchanging heat absorbed by melting of said biocompatible ice slurry The composition according to claim 1, comprising

11. A composition for use in reversibly inhibiting one or more peripheral nerves in a subject in need thereof, wherein the reversible inhibition comprises accessing a tissue comprising one or more peripheral nerves and injecting a biocompatible ice slurry around the one or more peripheral nerves, the biocompatible ice slurry being configured to inhibit the one or more peripheral nerves in the subject for a duration sufficient to cool the one or more peripheral nerves and the inhibition being reversible, composition.

12. The composition according to claim 11, wherein the injection of the biocompatible ice slurry around the one or more peripheral nerves comprises delivering the biocompatible ice slurry along the perineural sheath of the one or more peripheral nerves.

13. The composition according to claim 11, wherein the biocompatible ice slurry is configured to cool the one or more peripheral nerves to a temperature sufficient to crystallize a plurality of lipids of the myelin sheath of the one or more peripheral nerves.

14. The composition according to claim 11, wherein the biocompatible ice slurry is configured to cool the one or more peripheral nerves to a temperature of about 5°C to about -40°C.

15. The composition according to claim 11, wherein the biocompatible ice slurry has a first equilibrium temperature of about 4°C to about -30°C.

16. The composition according to claim 15, wherein the biocompatible ice slurry has a second equilibrium temperature of about 2°C to about -30°C.

17. The composition according to claim 11, wherein the duration sufficient to inhibit the one or more peripheral nerves in the subject is at least about 5 minutes.

18. The composition according to claim 11, wherein the biocompatible ice slurry comprises a plurality of ice crystals.

19. The biocompatible ice slurry is configured to cool the one or more peripheral nerves by tissue cooling, the tissue cooling comprising (i) exchanging heat stored by the biocompatible ice slurry and the heat capacity of the tissue, (ii) exchanging heat released by crystallization of one or more lipids of the tissue or one or more lipids of the myelin sheath of the one or more peripheral nerves, and (iii) exchanging heat absorbed by melting of the biocompatible ice slurry The composition according to claim 11, comprising

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