AU2016256812A1 - Product or process for modifying skin and spraying apparatus - Google Patents

Abstract

A storage and spraying vessel for spraying a cryogenic material on a skin area of an animal in order to effect a cryogenic freeze or cryosurgical techniques. Also disclosed is a method of tautening skin of an animal by reducing the size of a skin fold or skin area of the animal including the steps of clamping the skin fold to present an area of skin to be treated, applying a cryogenic material to the area of skin for a predetermined time period in order to freeze the area of skin, wherein after application of the cryogenic material the skin surrounding the affected area of skin contracts or tautens and the area of skin has a reduced skin area and/or eliminated skin fold. There is also disclosed a tool for clamping a skin fold of an animal to which a cryogenic material is applied. Is Fia. ±

Description

PRODUCT OR PROCESS FOR MODIFYING SKIN AND SPRAYING

APPARATUS

Field of the Invention

The present invention relates to a storage and spraying vessel used in a method of tautening skin and/or reducing skin folds, particularly in the tail and breach areas of an animal. The present invention also relates to a tool for clamping the skin of an animal in assisting in the method. 2

Background of the Invention

Merino sheep are commonly bred in Australia and New Zealand for their high quality wool. A trait of the Merino sheep is their loose skin which can result in the presence of skin wrinkles or skin folds. Figure 1 shows the presence of tail and breech wrinkles 4 present at the rear of a sheep 2.

Wrinkles or skin folds 4, such as those in the regions of skin bounded by lines 6 and 8 in Figure 2 can create a warm and moist protected environment which, given their close proximity to the sheep’s perineum, are susceptible to soilage by the sheep’s urine and faeces, thereby forming a suitable breeding ground for female flies to lay their eggs. Once the eggs hatch the larvae infest the sheep’s skin causing skin necrosis and lesions which may become infected and ultimately lead to death of the animal if left untreated. This process is known as flystrike or cutaneous myiasis and is particularly prevalent in Australia given the presence of the primary strike fly in association with the hot and humid conditions and the predisposition of merino sheep with wrinkly skin. A technique commonly used to overcome this problem is known as ‘mulesing’ whereby four areas of skin about the tail and back of hind limbs of a sheep are cut open without anaesthetic in order to remove skin and reduce wrinkles in areas which are susceptible to cutaneous myiasis. This causes considerable pain to the animal, predisposes the area to infection, undergoes a slow healing process, and is a technique which is strongly opposed by animal rights groups.

Furthermore, in the process of reducing skin folds, there is a need to securely pinch an area around the skin fold which provides adequate exposure to a cryogenic fluid without harming the subcutaneous layer as well as deeper layers in the skin of the animal. At present there is no suitable tool apparatus to carry out this procedure.

Furthermore, there is also a requirement to provide a dispensing container or spraying apparatus to emit a cryogenic fluid at a particular temperature range, pressure range, flow rate as well as allowing for a mix of gaseous and aqueous fluid to the skin fold to be treated. At present there is no such spraying equipment available to provide these features.

Thus it would be advantageous to provide a new apparatus or process for tautening skin and or reducing skin folds which substantially ameliorates one or more of the aforesaid problems.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art in Australia.

Disclosure of the Invention

According to an aspect of the invention, there is provided a storage and spraying vessel for spraying a cryogenic material on a skin area of an animal in order to effect cryosurgical techniques, the vessel including: a first portion having an inner wall and an outer wall with a vacuum space located between the inner wall and the outer wall; a second portion connected to the first portion, said second portion having a single wall and having no vacuum space; an outlet through which said cryogenic material flows; wherein the cryogenic material is able to be kept within the first portion within a predetermined temperature range and part of the cryogenic material is able to be in a gaseous state to maintain pressure within the vessel to enable release of a variable mixture of gaseous and aqueous cryogenic material through said outlet.

The outlet may have attached thereto a hose, dispensing bar and/or nozzle and valve means to direct and control the cryogenic material onto said skin area. The second portion of the vessel is preferably frustoconical in shape. Preferably an end of the second portion remote from where the second portion connects to the first portion has an opening to receive the cryogenic material. Preferably said end has a lid and seal arrangement that is releasably attached thereto to enable filling of the vessel with the cryogenic material and sealing the material within the vessel. Pressure within the vessel can be up to 150kPa. The vessel may further include a draw tube connected at one end to the outlet and having another end extending into aqueous cryogenic material inside the second portion. Preferably the cryogenic material is liquid nitrogen.

According to an embodiment of the invention, there is provided a method of tautening skin of an animal by reducing the size of a skin fold of the animal including the steps of: clamping the skin fold to present an area of skin to be treated; applying a cryogenic material to the area of skin for a predetermined time period in order to freeze the area of skin; wherein after application of the cryogenic material the skin surrounding the affected area of skin contracts or tautens and the area of skin has a reduced or eliminated skin fold.

According to another embodiment of the invention, there is provided a tool for clamping a skin fold of an animal to which a cryogenic material is applied, the tool including: a pair of handles connected at a pivot point to enable rotational movement of one handle in said pair with respect to the other handle in said pair; a cylindrical clamp attachable to a first end of each of said handles, said cylindrical clamps being substantially elongate; a hook located at a second end of one of the cylindrical clamps and at least one groove located adjacent a second end of the other of the cylindrical clamps; such that each cylindrical clamp clamps against a respective side of the skin fold and is retained in the clamped position by latching said hook in one of said at least one groove. 4

According to an embodiment of the invention there is provided a method of tautening skin comprising freezing the skin. The epidermal and dermal layers of the skin may be frozen. The method may reduce wrinkles or skin folds of the skin. The method may increase the skin tension or tautness. For the purpose of this specification skin wrinkles and skin folds are interchangeable terminologies. These terminologies are used within the sheep industry to describe the result of skin looseness.

Freezing the skin may comprise causing intracellular ice or crystal formation in the skin. This may lead to irreversible damage of the skin. Thus the or some of the skin may contract, scab and form a scar. The skin surrounding the treated area may also contract or tauten.

Freezing the skin may cause damage to the collagen layer of the dermis. Scarring may result. This may lead to contraction of the skin.

Freezing the skin may comprise achieving a temperature of less than 0 ( zero) degrees Celsius in the skin. More particularly, the temperature achieved in the skin may be less than minus 25 degrees Celsius. Even more particularly, the temperature may be less than minus 50 degrees Celsius. The treated skin may feel solid when the freezing agent is applied. Optimally, the temperature in the skin is between minus 60 degrees Celsius and minus 80 degrees Celsius.

Freezing the skin may comprise applying a freezing agent or cryogenic material to the skin of the animal. The freezing agent may be at a temperature less than minus 5 degrees Celsius. More particularly, the temperature of the freezing agent may be less than minus 60 degrees Celsius. Even more particularly, the temperature may be less minus 190 degrees Celsius.

The freezing agent may be applied in vivo. The freezing agent may comprise a cryogen. The cryogen may comprise liquid nitrogen or liquid oxygen or a combination of liquid nitrogen and liquid oxygen. However, extreme caution must be applied when using solely oxygen as a cryogen due to its severe oxidising effects. The freezing agent may be applied by spraying on to the skin of the animal and may comprise a mixture of aqueous and gaseous cryogen.

The region of skin to be treated may extend along the back of the hind leg and lateral or substantially parallel to the sheep’s perineum. This region may be called the breech region.

The region of skin to be treated may extend along the lateral aspect of the tail which hangs posterior to the sheep’s perineum. This region may be called the tail region.

Wrinkles may be reduced in the region of the skin treated. Additionally wrinkles may be reduced in the area of skin surrounding the region of skin treated. The area of surrounding skin in which wrinkles may be reduced may extend up to 100mm beyond the region of skin treated. Suitably, it may extend up to 50mm beyond the region of skin treated.

The method may be bloodless. The method may be non-invasive. The method may comprise shielding the skin around the region of skin to which the freezing agent is to be applied. The method may comprise clipping hair which covers the skin prior to applying the freezing agent. The hair may comprise wool.

The method may comprise spraying the freezing agent onto the skin through variable lengths of wool.

The method may comprise clamping the wrinkle of skin prior to applying the freezing agent.

The method may comprise spraying the freezing agent at a rate between 5 and 800 grams per minute. More specifically, the rate may be between 50 and 700 grams per minute. Even more specifically, the rate may be between 140 and 600 grams per min.

The method may comprise spraying the freezing agent on to the skin for between 5 and 60 seconds. More specifically, the freezing agent may be sprayed on to the skin for between 5 and 30 seconds.

The cryogen may be in part liquid and part vapour form as it contacts the skin. The freezing agent may be sprayed continuously on to the skin.

The freezing agent may be sprayed longitudinally along the skin fold or skin or both. It may be sprayed along the designated region of skin in a line, in a lengthwise back and forth fashion, or in a crosswise zigzag fashion.

The method may comprise allowing the skin to thaw before reapplying the freezing agent. The skin may be allowed to thaw for 15 to 60 secs. Suitably, the skin may be allowed to thaw for between two and three minutes. The freezing agent may be re applied immediately or some time after the initial application, especially if skin solidity is not achieved sufficiently.

The freezing agent may be sprayed between 0.5 and 10 cm away from the skin. More particularly, the freezing agent may be sprayed between 2 and 4 cm away from the skin.

The skin may be animal skin. More particularly it may be sheep skin. The sheep may be of the Merino type. Suitably, it may be a lamb, weaner, or older sheep. The sheep may generally be between 1 week and 18 months of age when presented for treatment.

The method may comprise restraining the sheep prior to application of the freezing agent. The sheep may be restrained on its haunches or in a marking cradle. The sheep may be restrained in a standing position.

The method may be used to treat animals en masse. It may be used in conjunction, and without interfering, with normal animal husbandry procedures.

In another aspect the invention provides a method of reducing or removing skin, wrinkles or both comprising freezing the skin. The wrinkles may be reduced by tautening of the skin which may occur following freezing.

The degree of tautening may depend on the area of skin treated. An increase in the skin area applied with cryogen, may result in an increase of surrounding skin tautening.

Sheep with loose skin have increased predisposition to fly strike. These animals generally have more skin wrinkles. Skin wrinkles may be significantly reduced when an appropriate skin area is treated.

In an embodiment, the invention provides an apparatus for spraying a freezing agent on to skin, the apparatus comprising, a bottle for holding the freezing agent, and dispensing means for dispensing the freezing agent disposed on the bottle, the dispensing means comprising a nozzle having an opening for passage of the freezing agent, the opening or internal diameter being between 1.0mm and 6.0 mm in diameter. This compares with about 2.2mm for medical applications.

The nozzle may be interchangeable.

The bottle may be double walled. Thus, the bottle may comprise an inner wall and an outer wall with a space therebetween. The walls may be made of steel, in particular mild steel or stainless steel. There may be a substantial vacuum in the space between the walls.

The dispensing means may comprise a variable flow valve for adjusting the flow of the freezing agent out through the nozzle. The dispensing means may comprise a draw tube for drawing up freezing agent in the bottle.

The apparatus may be adapted to spray the freezing agent at a rate between 5 and 800 grams per minute. More specifically, the rate may be between 50 and 700 grams per minute. Even more specifically, the rate may be between 140 and 600 grams per minute.

The apparatus may be adapted to spray an area of skin between 10 and 30 mm in diameter when the opening is between 5 and 70 mm away from the skin.

In another aspect the invention provides a nozzle for a spray bottle containing a freezing agent, the nozzle having an opening for passage of the freezing agent, the opening being between 1.0 and 6 mm in diameter or between 3.0mm and 3.5mm.

Brief Description of the Drawings

By way of example only, embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings, in which:-

Figure 1 is a rear view of a sheep with skin folds prior to cryogenic treatment; Figure 2 is a rear view of the sheep of Figure 1 and shows area of skin treatment; Figure 3 is a side view showing a sheep undergoing cryogenic skin modification treatment;

Figure 4 is a side sectional view of spraying apparatus in order to effect cryosurgical techniques or effect a cryogenic freeze according to one embodiment for spraying a cryogenic fluid onto the skin of an animal;

Figure 4A is a perspective view of a storage and spraying vessel in order to effect cryosurgical techniques or effect a cryogenic freeze according to a further embodiment to enable spraying of a cryogenic fluid onto the skin of an animal; Figure 4B is a side view of a vessel similar to that shown in Figure 4A;

Figure 4C is a view of the vessel of Figure 4A having a hose and applicator or dispenser attached thereto for dispensing the cryogenic material;

Figure 4D is a view of the vessel of Figures 4A and 4C with the hose disconnected from the vessel;

Figure 5 is a perspective view of a tool, in particular forceps, for grabbing and holding a skin fold having a pair of substantially identical cylindrical clamps, such as rods;

Figure 6 is a perspective view of a tool similar to the tool shown in Figure 5 with a pair of cylindrical clamps having differing lengths;

Figure 7 shows a rear view of a sheep with a pair of the tools shown in Figure 5 applied to skin folds around the edge of the tail of the sheep;

Figure 8 is a rear view of a sheep having applied to skin folds in the tail of the sheep a pair of forceps similar to the tool shown in Figure 5 with curved handles; Figure 9 is a rear view of a sheep similar to Figure 8 with clamping tools that have one or more cylindrical clamps with a looped section therein to enable cylindrical clamps of another tool to laterally pass underneath such a cylindrical clamp;

Figure 10 is a side sectional view of the layers of skin on an animal before treatment by the present method;

Figure 11 is a side sectional view of the outer layers of the skin of the animal with a tool of Figure 5 applied to a skin fold such that the epidermis and dermis is clamped ready for treatment;

Figure 12 is a rear view of the sheep of Figure 1 approximately two weeks post treatment;

Figure 13 is a rear view of the sheep of Figure 1 approximately four to six weeks post treatment; and

Figure 14 is a side sectional view of the outer layers of the skin of the animal after treatment showing scar tissues and tautening or tightening of the skin in the immediate region of the scar tissue.

Detailed Description of Elements of the Drawings

The various elements identified by integers in the drawings are listed in the following integer list.

Integer List 2 lamb 4 skin wrinkle/fold 6 breech region 8 tail region 10 marking cradle 12 spray bottle 14 liquid nitrogen and liquid nitrogen vapour 16 trigger 18 hind leg 20 tail 21 spraying apparatus 22 container 24 liquid nitrogen 30 inner wall 32 outer wall 34 vacuum space 40 nozzle 44 trigger 46 draw tube 52 flow valve 62 safety relief valve

Detailed Description of the Preferred Embodiments

Referring to Figures 1 and 2 there is shown the hind legs 18 and tail 20 of an animal such as a Merino lamb, generally designated 2, with extensive breech and tail skin wrinkles 4. Breech regions and tail regions, shown by outlines referenced 6 and 8 respectively, represent areas of skin to which a cryogen, such as liquid nitrogen, is to be applied during cryogenic treatment.

The breech regions 6 extend separately on both sides along the upper hind legs, adjacent to the tail and lateral or parallel to the perineum. Each breech region 6 is approximately 150 mm long and 35 mm wide. Due to its close proximity to the perineum, the breech region 6 is prone to being soiled by urine and faeces, leaving wrinkles in the region susceptible to cutaneous myiasis. The area of treatment varies according to the animal’s age and animal type (degrees of wrinkliness)

The tail regions 8 extend laterally on opposite sides along the upper aspect of the tail 20, posterior to the perineum when the tail 20 hangs down. Each tail region 8 is about 85 mm long and 25 mm wide, and its closeness to the perineum also leaves it susceptible to soilage by the sheep’s urine and faeces. This can lead to cutaneous myiasis in the tail regions 8.

With reference to Figure 3, wrinkles 4 in and surrounding the breech regions 6 and tail regions 8 may be reduced, thereby reducing incidence of cutaneous myiasis, in the following manner:

Mount the lamb 2, being between 1 and 12 weeks of age, on its haunches securely in a marking cradle 10 with its hips flexed.

Grasp a spray bottle 12 containing liquid nitrogen 14 with one hand and grasp the sheep’s tail 8 with the clamping tool 20 in the other hand. The tail 8 grasped using the clamping tool is to be discussed in relation to Figures 5 to 9.

Rotate the clamp handles 20 to expose the other skin sections of the breech area to be treated;

Hold the tip of the nozzle of the spray bottle 3 to 7 cm away from the breech region.

Depress a trigger 16 on the spray bottle in order to spray liquid nitrogen 14 on to the breech region 6.

Spray longitudinally back and forth along the breech region 6 for 10 seconds before releasing the trigger.

Hold and rotate the clamp handles away from the sheep’s body and spray the section of skin that is exposed;

Spray longitudinally back and forth along the breech region 6 for 10 seconds, maintaining the tip of the nozzles 3 to 7 cm away from the skin. Alternatively, the following can be performed:

Mount the lamb 2, being between 1 and 12 weeks of age, on its haunches securely in a marking cradle 10 with its hips flexed.

Using electric shears or clippers, shear the wool covering the breach and ^ tail edges.

Grasp a liquid nitrogen dispenser unit 12 containing liquid nitrogen 14 with one hand and pinch and clamp the loose breech skin including wrinkles with a skin clamp 20 with the other hand.

Hold the tip of the probe 22 of the spray bottle 3 to 7 cm away from the breech region.

Depress a trigger 16 on the liquid nitrogen dispenser in order to spray liquid nitrogen 14 on to the breech region 6.

Spray longitudinally back and forth along the one aspect of the tented or pinched skin for 10 seconds, defined by the skin clamp before releasing the trigger.

Then slightly rotate the skin clamp outwards to exposure the other aspect of the pinched skin. Repeat the liquid nitrogen spray application where the area of skin application is defined by pinched skin height and skin clamp jaw ventrally.

Repeat skin clamp technique and Liquid Nitrogen spray application to the other breech area.

Clamp section of skin on lateral tail edge.

Spray longitudinally back and forth along the tail region for 10 seconds, maintaining the tip of the probe 3 to 7 cm away from the skin.

Rotate skin clamp and repeat process to other aspect usually ventral of tail edge.

Repeat the same process to the other lateral tail skin edge.

Follow similar process to tail end if tail has been previously docked.

The nozzle 40 of the spray bottle 12 (or 21) is specially designed with an opening of between 1 .Omm and 6.0 mm in diameter or cylindrical slot for the passage of liquid nitrogen. Its shape can be cylindrical or oval for the passage of the cryogenic material. This allows high flow rates of around 150 to 250 grams per minute of liquid nitrogen vapour mix to be expelled. Thus with the nozzle held at about 3 to 7 cm from the skin, much of the liquid nitrogen reaches the skin in a combination vapour and liquid form. The liquid Nitrogen quickly evaporates once exposed to air and upon skin contact, thereby limiting spillage and run off from the designated region.

In the days following application of the liquid nitrogen an inflammatory response ensues with skin darkening and slight swelling occurring at the application site in the breech and tail regions, but the lamb is still fully mobile and only elicits slight pain response on deep palpation of the treated region within 1-3 days post application. Over the next couple of weeks as the inflammation abates the skin in the treated region contracts, a scab forms and eventually lifts, forming a generally lineal scar, resulting in tautening of the skin in the larger surrounding area and results in reduction or flattening of the wrinkles in the breech and tail regions, thereby reducing the incidence of cutaneous myiasis in the sheep.

Referring to Figure 4 there is shown a spraying apparatus 21 including a container 22 which contains a liquid cryogen 24, in this case liquid nitrogen. The container 22 is insulated essentially from the neck 26 down to the bottom 28 of the container 22 whereby there exists an inner wall 30, and an outer wall 32 with a vacuum space 34 in between the inner wall 30 and the outer wall 32. The container 22 may be made from mild steel or stainless steel and therefore insulates the liquid nitrogen 24 to keep it at a predesignated temperature. The upper reaches or upper section of the container 22 at neck 36 does not have the vacuum space 34 and enables partial evaporation of the liquid nitrogen so that a mixture of gaseous nitrogen and aqueous nitrogen is able to be emitted through tube 38 and nozzle 40. A higher percentage of liquid cryogen compared to gaseous nitrogen is able to be ejected from spraying apparatus 21 compared with existing spraying apparatus used in a medical application where a much greater percentage of gas is emitted. A user can hold the container 22 through handle 42 and operates the container 22 to inject the liquid nitrogen by using trigger 44 and pushing trigger 44 towards the container 22. The applied pressure of the cryogen exiting nozzle 40, which dictates the amount of displacement of the valve 52, is proportional to the amount of hand pressure applied to trigger 44. Typically the trigger is pressed inwardly about one-third to a half of the distance to the container 22. It is to be noted that a much higher percentage of liquid nitrogen is delivered to the skin than compared with medical spray containers, which typically only provide about 20% of the total volume as a liquid. The nozzle and container of the present invention supply at least 40% liquid cryogen of the total volume of cryogen emitted from the nozzle 40, and generally between 50% and 70% liquid cryogen of the total volume of cryogen.

Liquid nitrogen is drawn out through the draw tube 46 whereby upon depressing trigger 44, lever or pin 48 forces washers 61, 63 upwardly(or just washer 63 where part 61 designates a portion of the end of the trigger 44 connected to the head through pin 48). These washers 61, 63 are connected to the valve 52 by rod/shaft 51 so that spring 50 moves upwardly, under pressure from the valve 52, to open valve 52 which enables the passage of a mixture of gaseous and liquid nitrogen from the draw tube 46, through the tube 38 and the nozzle 40 under pressure from within container 22. A seat 54 together with O ring seal 56 ensures that there is no escape of nitrogen from the top of the bottle or container 22 and that it solely goes through the tube 38. Valve 52, sits into a corresponding inverted conical V-shaped element 65 having an aperture therein, through which liquid nitrogen flows which is enabled through the top part or neck 36 of the container 22 not being insulated so that the nitrogen boils faster at this location in order to keep the pressure up within the container 22. Thus the further upward the valve 52 is drawn, with more pressure from the trigger 44, the greater the volume of cryogen that flows out through tube 35 due to the greater volume available in the V-shaped element 65. The thickness of the container wall at neck 36, where there is no vacuum space, is about 9mm. This ensures that when the dispenser unit is tilted forward during the application process, the liquid nitrogen within container contacts the container wall neck 36 and there is sufficient heat transfer from the environment to keep part of the liquid nitrogen boiling with resultant production of the gas phase to ensure a relatively high and continual flow rate. The external diameter of the wall at the neck 36 is about 70 to 80mm, preferably 75 to 77mm and the internal diameter is preferably 60 to 70mm. The external diameter at the lower part of the container 22 where there is vacuum space 34 is preferably about 140 to 150mm.

The trigger 44, as well as the nozzle 40 and tube 38, form part of the head 39 of the container 22 which is screwed onto the top part of the container 22 via threads 58 with a pair of O ring seals 59 and 60 positioned to prevent escape of nitrogen vapour. The draw tube 46 is rigidly affixed by screw means to shaft 61 which is threaded and hollow to accommodate the valve 52 and spring 50. Manual as well as automatic relief valves as shown at 62 may be used to relieve pressure from within container 22. 4

The spraying apparatus 21 is suitable for treating sheep or other animals en masse. Draw tube 46 may have a diameter range of between 2.5mm to 5.0mm. The diameter is 3.2mm in the embodiment shown in Figure 4. Draw tube 46 is screwed into the centrally located shaft 61 at the top of the container. The nozzle 40 is interchangeable to provide a variable flow rate of nitrogen, once the valve 52 is drawn up, and typically it has an aperture range of 1.0mm to 6.0mm. Thus the inlet and outlet at respective ends of the internal tube 35, through which the freezing agent is dispensed, is in the range of 1.0mm to 6.0mm in diameter. The operator can adjust the diameter of the nozzle passage, through a knob or lever (not shown) as well as the passage through the valve 52. A relief valve or opening 64 is also located at the bottom of the container. This allows passage of liquid or gaseous nitrogen to the atmosphere.

Generally the spraying apparatus 21 has a capacity of about 2 kg of liquid nitrogen in the embodiment shown in Figure 4. It is possible that the size of the container 22 can vary to hold anywhere between 0.5 kg and 5 kgs of liquid nitrogen when used in an en masse application.

The double walled container 22, although it is a good insulator, still allows sufficient heat transfer through the walls in order to cause evaporation of some of the liquid nitrogen, which has a boiling point of about minus 196 degrees Celsius. This results in a build-up of pressure in the bottle up to a level of about 150kPa, and at which level the safety relief valve 62 is set to relieve any further pressure build up. The operating pressure may range from a few kPa to 150kPa. In a preferred embodiment, the optimal range is between lOkPa and lOOlcPa. This possible variation of pressure in the container 22 results in variable vapour and liquid output flow rates. The flow rates can then be adjusted as required by adjustment of a flow valve 52 by the operator using a lever or knob (not shown).

In a further embodiment, the double walled container 22 may have an outlet in a double sided wall near the base as shown in 64, which allows the vacuum to occur within the container 22.

Referring to Figures 4A and 4B there is shown a storage and spraying vessel 130 which spraying a cryogenic material on a skin area of an animal in order to effect cryosurgical techniques or effect a cryogenic freeze. The vessel 130 has a first, lower portion 134 and a second, upper portion 136 which is in the form of a ffustoconical member attached or connected to the upper side or ledge 133 of lower portion 134. The portion 136 serves as a neck to the vessel 130. The top of the neck 136 has an opening 131 (Figure 4D) adapted to enable liquid nitrogen to be poured into the vessel 130. It is sealed by a cap, lid or nut 134 and a teflon seal 139, the cap 134 having a pair of handles 145 for insertion and removal of the cap 144 from the portion 136. A tube 138, which is double-walled and has the some insulating ability, provides a support for draw tube 142 which is narrower in diameter than the tube 138 and actually extends into the interior of the lower portion 134 into the liquid nitrogen(see Figure 4B). The draw tube 142 at the top is bent perpendicularly and at the end of the tube 142 there is an outlet 140 which is adapted to fit to a hose, control valve and to an applicator, such as a nozzle or tube dispenser, in order to apply liquid nitrogen or a mix of liquid and gaseous nitrogen to a skin area of an animal in order to tauten the skin. The lower portion 134 is vacuum sealed similar to the container of Figure 4 in that there is an outer wall 133, an inner wall 135 and a vacuum space 137 in between the outer wall 133 and inner wall 135. The vessel 130 can be made from mild steel or stainless steel and therefore insulate the liquid nitrogen 168 to keep it at a predesignated temperature. The upper portion or neck 136 has a single wall and does not have the equivalent vacuum space 137 and therefore enables partial evaporation of the liquid nitrogen so that a mixture of gaseous nitrogen and liquid or aqueous nitrogen is able to be admitted through tube 142 at outlet 140. With neck 136, by its nature of being non-insulated this allows heat to passively transfer into the vessel 130 which then exerts a boiling effect on the liquid nitrogen which is in its liquid state at -196°C. This added heat results in pressuring the liquid nitrogen with the subsequent boiling of some of the liquid nitrogen to the gaseous state. When liquid nitrogen goes to a gaseous state, such a gas state has pressure up to 70 times greater than the liquid state such that the internal pressure within the vessel 130 is increased which then enables the liquid nitrogen, with some component of a gaseous form of nitrogen, to flow out through the tube 142 and the outlet 140.

The pressure in the vessel is pre-set to 22psi or about 150KPa. A manual gas relief valve 148, operated by handle 150, is important in the process of refilling the vessel 150 with liquid nitrogen. The relief valve 148 is opened to ensure that all the pressure that is within the vessel 130 is released. This is so that the cap 144 can be safely opened for refilling. The cap 144 is approximately 75-100mm in diameter. A variable gas relief valve 146 is located on the opposite side of handle 150 to the valve 148.

When the vessel 130 is initially filled with liquid nitrogen the vessel 130 is usually at room temperature. The rate of evaporation of liquid nitrogen is high at this stage. However once the cap 144 is secured to the top of neck 136 and then the teflon seal seals the vessel such that there is no gas leakage, then a pair of relief bursting discs 154 and 156 release nitrogen gas in the case where the variable gas relief valve 146 cannot release the built-up pressure in the gaseous nitrogen fast enough. The vessel 130 or at least the liquid nitrogen, after pouring in the vessel 130, settles in approximately 2-5 minutes to a more static state. When the liquid nitrogen in the vessel becomes static, the manual relief valve 148 can be opened to reduce the internal pressure within the vessel 130 to preferred operating pressure settings. The preferred settings are generally between 5 and 155 kPa. The lower the operating pressure within the vessel 130, then the colder the liquid nitrogen that will be dispensed to the animal’s skin, effecting a faster cryogenic skin effect. A second or subsequent refill of liquid nitrogen into the vessel 130 will not provide as much heat transfer to the liquid nitrogen to form a partly gaseous state of the nitrogen as the container or vessel is already at a much reduced temperature. Instead heat can be directed to the upper portion or neck 136 which has a single wall, to increase the pressure of the nitrogen within the vessel 130. Such heat can be obtained from direct sunlight, radiant heat from the atmosphere or from a warming device or heat from a gas burner, for example. Thus, the liquid nitrogen is able to be kept within the first portion 134 within a predetermined temperature range and part of the liquid nitrogen is able to be in a gaseous state to maintain pressure within the vessel 130 to enable release of a variable mixture of gaseous and aqueous cryogenic material through the outlet 140. A gauge 158 enables the display of the internal pressure of the gaseous nitrogen in the vessel 130. Lifting handles 160 and 162 (Figure4D) enable the vessel 130 to be lifted by one or two people and a square tray 164 is provided for extra stability or support in which the lower portion 134 of the vessel 130 sits. When the liquid nitrogen is refilled, it is poured to a level 166 shown in Figure 4B such that it is just below the area where the upper portion 136 joins the lower portion 134. This keeps liquid nitrogen within the area that has a vacuum space 137 of the lower portion 134. A vacuum extraction point or valve 152 is also provided on the side wall of the lower portion 134 of the vessel 130.

As mentioned previously, when required for use after being transported to a certain destination, a hose, valve means and applicator with a nozzle can be attached to the outlet 140 ready for use to a predefined area of skin of the animal to be treated. This is shown in each of Figures 4C an 4D. In Figure 4C, hose 170, which is double-walled having a vacuum space there between similar to the lower portion 134, is connected through suitable joiners to outlet 140. The other end of hose 170 is connected to valve means 172, such as a solenoid valve, through a joiner which is activated through switch 176. The solenoid valve is then connected to a suitable dispenser, nozzle or dispensing bars to dispense the cryogenic material. Figure 4D shows the hose 170 disconnected from the vessel 130 but still attached to the draw tube 142 and threaded cap 144, in order allow filling of the vessel 130 with liquid nitrogen.

The capacity of the vessel 130 can be anywhere from 10 litres up to 250 litres. A 10 litre vessel can have a height of 500mm, a diameter of the lower portion 134 of 250mm and the height of the lower portion up to 374mm. Alternatively the vessels can be manufactured to hold up to 250 kg of nitrogen or more. It can also be on a trolley/wheel system or alternatively can be lifted by one or two people.

Referring to Figures 5 and 6 there is shown a tool 70, in the form of forceps, which is used to clamp a skin fold or wrinkle of the skin of an animal. The forceps 70 has a pair of handles 71 and 72 which are pivoted and joined at pivot 75. At one end of handle 71 there is located a transverse cylindrical clamp or rod 74 and at one end of handle 72 is located a transverse cylindrical clamp or rod 73 which acts with rod 74 to clamp a skin fold. The diameter of each of rods 73, 74 can be between 1mm and 5mm, preferably 2.7mm. Spring 76 enables the forceps or the handles of the forceps 71 and 72 to be apart in a resting state so that their rods 73 and 74 are apart.

Upon depressing the handles 71 and 72 together against the forceps spring 76, the rods 73 and 74 are drawn together around the skin fold and by virtue of a hook 82 at end 78 of handle 72 and a series of grooves 84 at end 80 of handle 71, and as is shown in Figure 6, a number of positions can be located to keep the rods 73 and 74 locked or engaged against the base of the skin fold. This is more clearly shown in Figure 11. Thus depending on the thickness of the skin fold and degree of clamping force required, any one of the grooves 84 can be used to receive the hook 78 to clamp the tool 70 in a fixed position. Unclamping is simply a matter of depressing the handles against each other further to release the hook 78 from the respective groove 84. The handles 71 and 72 then return to their natural resting state with the rods 73 and 74 apart.

Figure 6 shows a further rod 85 which replaces rod 74 in Figure 5. Rod 85 is generally between 30mm to 50mm long compared with rods 73 and 74 which can be between 60mm and 150mm long, but preferably about 100mm long. The advantage in having a shorter rod is particularly for where clamping is required around the lower part of the sheep’s tail to allow for one or more clamps to be simultaneously applied against skin folds in the tail of the sheep, and the end section of the tail skin is raised forming a raised V for the whole perimeter of the tail.

Shown in Figure 7 is a pair of forceps 70 applied to respective sides 90 and 92 of the tail 20. One of the rods of each of the forceps 70 lies underneath the tail so that the whole tail is clamped. The operator can then freely use the spraying apparatus 22 to spray liquid nitrogen at the desired location. As an alternative a skin fold on the top part of the tail may be clamped between the rods 73 and 74 and then the operator sprays the designated area. The operator can then spray on the other side of the tail 20 by releasing the clamp firstly and then reapplying the clamp to the underneath surface to produce a skin fold near the edge of the tail 20 and thereafter spray liquid nitrogen to the desired area. Each of the breech sections identified by numeral 6 either side of the perineum can then be similarly grasped between the rods 73 and 74 of forceps 70 to apply a liquid and gaseous nitrogen mixture to the particular skin fold.

With reference to Figure 8 (and Figures 5, 6) there is shown an alternative set of forceps 70 applied to breech skin. The handles of the forceps 70 are curved to assist in providing better positioning or gripping of the forceps handles compared to the arrangement of handles shown in Figures 5 and 6. Points 94 and 95 represent the junction of the handles welded to the clamps/rods 73, 74, 85. One of the rods or both of the rods of the forceps may be looped as is shown at 96 and 97 to allow for multiple clamping via a series of forceps so that where two clamps meet, this makes it easier to have one clamp handle going underneath another clamp handle.

With regard to Figure 9, as with Figure 8, tail clamps are shown but instead of having a curved set of handles for each set of forceps, they may be bent at a particular angle at the clamp handle attachments points 94 and 95 so that a pair of relatively straight handle sections meets at 94 and 95 with clamp handle attachments.

Referring to Figure 10 there is shown a cross section 100 of an animal’s skin, subcutaneous tissue and muscle. The skin primarily comprises two layers being the epidermis 102 and dermis 104. The subcutaneous layer 106 is underneath the dermis 104 and the muscle 108 is beneath the subcutaneous layer 106. A wool follicle 110 is shown with its root embedded in the dermis 104. Also in the dermis 104 is shown an artery 112, a vein 114 with capillaries 116 located between the artery 112 and vein 114. A nerve ending 118 is also shown.

Referring to Figure 11, there is shown a cross section of the animal’s skin, subcutaneous tissue and muscle similar to Figure 10. However rods 73 and 74 of forceps 70 (shown end on) has clamped a section of skin or a skin fold 120 ready for treatment via the application of liquid and gaseous nitrogen. The skin fold 120 which has been clamped contains only the epidermis 102 and dermis layer 104. This is so that the complete epidermis layer and dermis layer of the treated skin is fully treated and undergone a freezing process. A third degree cryo burn, which occurs through the action or application of the cryogenic fluid through the complete skin layers is less painful than a first degree bum or a second degree burn. Upon application of the liquid nitrogen through the spraying apparatus 22, the skin right through to the centre of the skin fold 120 is frozen at an optimal temperature between minus sixty degrees Celsius and minus eighty degrees Celsius. Pinching isolates the skin from the subcutaneous layer and prevents any harmful destruction of the subcutaneous layer. When frozen, the cells produce large ice crystals particularly at around minus sixty degrees Celsius and thereafter undergo cellular necrosis. This is termed cellular lysis after the ice crystals form and melt from exposure to the liquid and gaseous nitrogen.

Figures 1,2, 12 and 13 are a sequence of rear views of a sheep 2 at various times before and after cryogenic treatment. This single case sequence illustrates the changes in the skin which can occur following cryogenic treatment.

Referring to Figure 1, there is shown a sheep 2 prior to cryogenic treatment. The sheep has generally vertically aligned skin folds 4 present at the rear of the sheep. In particular, there is one pair of skin folds 4 on opposite lateral aspects of the tail 20, and three pairs of generally parallel skin folds 4 along the back of the hind legs 18.

Figure 2 shows the sheep 2 of Figure 1 immediately following cryosurgical treatment. Outlined breech regions 6 and tail regions 8 represent areas of skin to which liquid nitrogen was applied, with the application of liquid nitrogen causing these areas of skin to be frozen at the time of treatment. The treatment areas will darken over the first day after treatment and then from that time, up to about seven days after, swelling of the skin will occur.

Figure 12 shows the sheep 2 of Figure 1 approximately two weeks post treatment. As shown, the treated areas of skin (i.e. the breech regions 6 and the tail regions 8) have contracted with resultant scabbing or skin crusts with hardened skin formation, appearing superficially like dry areas of skin with matted wool. Contraction of the skin in the breech and tail regions, 6 and 8 respectively, has resulted in flattening of the skin folds 4 within these regions. Additionally, contraction of the skin in the breech and tail regions 6, 8 has resulted in pulling of the surrounding skin towards the treated area, thereby reducing skin folds 4 in the surrounding skin. This process of contraction and scab formation generally takes place over 7 to 42 days after treatment.

Referring to Figure 13, the sheep of Figure 1 is shown approximately four to five weeks post treatment. The breech and tail regions of skin, 6 and 8 respectively, have further contracted to form longitudinal scars which do not grow wool. In addition, folds in the skin surrounding the breech and tail regions 6, 8 have further reduced with smoothness of the skin being evident in the general areas around the breech and lateral aspects of the tail.

Referring to Figure 14, there is shown a cross section 100 of the skin of the sheep 4 to 5 weeks after treatment. It is seen that scar tissue 122 remains in the epidermis 102 and dermis 104 while movement of skin towards the scar tissue 122, in the adjacent areas shown by arrows 124, has provided a tightening or tautening of the adjacent skin, and as a consequence of the freezing and tautening, the skin fold is removed or substantially reduced.

Example

The Australian Wool Innovation commissioned the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to undertake a pilot study to assess the time course and clinical impact of cold-induced skin necrosis and wound healing caused by the application of liquid nitrogen to skin on the breech and tail regions of sheep as a method to modify breech and tail conformation in order to reduce the risk of breech strike.

The anticipated advantages of the method over surgical mulesing include the absence of an open skin wound, accurate delivery of liquid nitrogen in a precise ‘dosing’ of each animal of the treatment modifying breach conformation. Furthermore less pain and discomfort and fewer systemic impacts than mulesing are additional anticipated advantages. Data was provided on the impact of the treatment on clinical signs including rectal temperature, heart rate, lung sounds, demeanour, appetite, freedom of movement, wound appearance and wound healing.

The animals studied and tested were six merino sheep aged about six months with a body weight range of 20-28 kilograms and gender being castrated males.

Vaccinations occurred on 21 March 2011 and then subsequently the sheep were crutched on 30 March 2011 with cryogenic treatment supplied on 6 April 2011. Breech wrinkle was scored according to the AWI/MLA Visual Sheep Score standard. Assessments were based on clinical observations of treated and control lambs.

Standard clinical procedures were employed, rectal temperature was measured by digital thermometer while heart and lung sounds were assessed with the aid of a stethoscope. Clinical examinations were made before offering feed in a communal feed trough. Appetite was assessed by the interest as shown by sheep in approaching and eating the newly offered feed. Ease of movement was assessed from outside the pen when the sheep were disturbed by the approach of a human and as the sheep approached the feed trough. Treated and control sheep shared a single pen so that assessments were made informally based on comparison between treated and control animals.

Treatment

The lambs were restricted in a cradle and the hind legs held forward by an animal handler standing at the head of the cradle. Skin on the side of the tail and beside the perineum was clamped in forceps, such as tool 70 ,to raise a fold of tissue to which liquid nitrogen was applied. The liquid nitrogen was applied via a modified applicator, such as the spraying apparatus 21. Skin temperature at the sites of application of liquid nitrogen was measured with infrared thermometer. Control lambs were placed in the cradle for measurement of bare areas and for photography of the breech.

Results - Breech Scores

Wrinkles on the tails of the three treated sheep appeared to be more pronounced when scored at 28 days than at day 1. At this time, the skin folds on the tails that had been treated with liquid nitrogen had not sloughed, which may account for the more pronounced appearance of the wrinkles. The decrease in breech score from day 0 to day 28 in control sheep is likely to reflect the effect of wood growth on accuracy of scoring breeches.

With regard to body temperature, there was identified a moderate increase in rectal temperature evident from about six to nine hours after treatment. In relation to the respiration rate, a substantial increase in respiration rate occurred at about six hours after treatment. The results suggest that the rate might still have been elevated at 24 or 48 hours afterwards. Regarding hear rate, this was highly variable between the animals and no clear trend was evident. No significant alterations in demeanour throughout the observation period were evident. All animals were considered in general to be bright, alert and responsive. There was also no significant effect on appetite observed. Little effect was evident on the movement of the animals. Treated animals were observed to stand with their tails tucked slightly under and to walk a little stiffly on their hind legs at about 9 hours after treatment on each of days one and two. By day three the sheep had returned to normal.

In conclusion it was evident that lambs experienced discomfort in the initial moments after application of liquid nitrogen to the skin. Subsequently there was a moderate increase in body temperature and respiration rate, indicative of a mild stress response to the treatment. In comparison to the known effects of mulesing and intradermal alternatives, the response appeared to be very mild and did not represent a substantial insult to the lambs. There was little impact on appetite and lambs remained bright following the treatment. They showed little restriction on freedom of movement. Mild swelling of the treated sites was noticeable for several days and was followed by hardening of the tissues without marked exudation except for a few hours at skin sites damaged by freezing of the skin to the forceps used as clamps. Subsequently the treated tissue became shrivelled and the overlying skin appeared to be dry and dead with the formation of a dark eschar before being shed over a period of several weeks to leave linear scars.

Claims (8)

1. CLAIMS:

   1. A storage and spraying vessel for spraying a cryogenic material on a skin area of an animal in order to effect cryosurgical techniques, the vessel including: a first portion having an inner wall and an outer wall with a vacuum space located between the inner wall and the outer wall; a second portion connected to the first portion, said second portion having a single wall and having no vacuum space; an outlet through which said cryogenic material flows; wherein the cryogenic material is able to be kept within the first portion within a predetermined temperature range and part of the cryogenic material is able to be in a gaseous state to maintain pressure within the vessel to enable release of a variable mixture of gaseous and aqueous cryogenic material through said outlet.
2. 2. A vessel according to claim 1 wherein the outlet has attached thereto a hose, dispensing bar and or nozzle and valve means to direct and control the cryogenic material onto said skin area.
3. 3. A vessel according to claim 1 or claim 2 wherein the second portion of the vessel is frustoconical in shape.
4. 4. A vessel according to claim 3 wherein an end of the second portion remote from where the second portion connects to the first portion has an opening to receive the cryogenic material.
5. 5. A vessel according to claim 4 wherein said end has a lid and seal arrangement that is releasably attached thereto to enable filling of the vessel with the cryogenic material and sealing the material within the vessel.
6. 6. A vessel according to any one of the previous claims wherein pressure within the vessel is up to 150kPa.
7. 7. A vessel according to any one of the previous claims further including a draw tube connected at one end to the outlet and having another end extending into aqueous cryogenic material inside the second portion.
8. 8. A vessel according to any one of the previous claims wherein the cryogenic material is liquid nitrogen.