Infiltration is one of the veterinary medical acts with more doubts and generates resistance in horse owners when deciding to use treatments.
Infiltration is merely an application of medication in the precise area of the injury rather than by general application.
What are the advantages and disadvantages of infiltration?

AS FOR THE ADVANTAGES WE CAN SAY THAT:
- Analgesic effects are achieved with stronger potent anti-inflammatory treatments than conventionally administered.
- The beneficial effects are longer lasting than those obtained with systemic medication
- By Avoiding the anti-inflammatory adverse effects that are produced at the level of stomach, liver, bone marrow, the dose and duration of treatment would be necessary to achieve a similar effect to that of local administration.
- It reduces high proportion amounts of the medication used, when administered through general anesthetics.
- Recovery times are dramatically reduced in some circumstances, allowing the horse to return to its activity in less time.

THE DISADVANTAGES CAN BE SUMMARIZED IN:
Risk of infection, which can be minimized by using strict aseptic techniques.
Technically difficult in addressing some of the deep joints.

The drugs can be administered systemically, general or local. When we administer them through general administrations, we do them either orally or by injection, where they are absorbed and distributed throughout the body,  a very diluted amount reaching the target organ, which is where we need the drug to exert its action.
These infiltrations are a way to get the medication to the injured area, thereby achieving a higher drug concentration in the affected area, thus more intense effects, longer lasting and sometimes totally curative.
Normally when infiltrated inside the joints, muscle mass or tendon sheaths and sometimes infiltrating the perilesional, or around the lesion, as in an active periostitic that is growing near and around a ligament injury.


In what kind of situation do we decide to conduct an infiltration?
IN JOINT DISEASE, chronic and degenerative. It is one of the most common situations. Many sport horses, sometimes develop degenerative joint disease from very early ages. As the years pass, the likelihood of developing such problems increases significantly.
Most modern treatments in the pathology of the articulate or sinew are based on infiltration in the area of injury with plasma rich factors in platelets or marrow, both obtained from the patient's own cells. The capacity for regeneration of injured tissue is with these much higher quality treatments, while minimizing the risks of relapses.

For the treatment of joint disease, we basically use the following tools:
INFILTRATION OF THE FETLOCK JOINT:
- Nonsteroidal anti-inflammatory steroids, oral or by injection, which will be effective as they are administered. Unfortunately they all have side effects when use is prolonged over time, it causes gastritis or ulcers, liver damage, decreased blood cell production and possibly kidney damage. So we must use a limited basis.
- Orthopedic shoeing, in general if there are problems the lie further in the distal parts of the limb.
- The chondroprotective, are naturally occurring substances that nourish the cartilage and delay the onset of the degenerative process.
- Alternative therapies such as homeopathy, acupuncture and ozone therapy.
Physical therapies such as hydrotherapy, laser, ultrasound, shockwave therapy, etc. ..
- Eventually we will use only joint infiltration. Coming to maintain one or two injections per year, with excellent results and at this rate the likelihood that collateral damage is very low, with all the tools available for joint therapy, these obtained the best results.
The latest treatments for joint or tendon pathology are based on infiltration into the injury site with platelet rich plasma factors or bone marrow cells, both obtained from the patient. The capacity for regeneration of damaged tissue with these treatments have much better quality and minimizes the risk of relapse.

Intralesional infiltration ecoguide marrow stem cells in a superficial flexor tendon, under general anesthesia

IN THE MUSCLE MASSES:
On many occasions horses show back, rump, or croup contractures but rarely back or neck. You can suspect resistance while in training, poor performance, stiffness or asymmetry and differences in behavior when changing one exercise to another.


Many times it produces a contracture symptom which causes pain, generates contracture and this way perpetuating the problem. We usually use physical therapy such as massages, coldness, rubs with different substances, or physical therapy. If these measures prove insufficient, we'll use local infiltration of the muscles contracted, with anti-inflammatories, muscle relaxants, local anesthetics or a combination of them all and in many cases they are a totally curative descontracturar, relaxing and allowing the fibers a complete reduction in inflammation.

Infiltration of the dorsal region of a chronic dorsal contructure , intervertebral spondylitis

In very chronic pain, we occasionally use iodinated derivatives, that generate a mild rubefacient effect, bringing to the lesioned area an increased blood supply and thus enhancing the endogenous anti-inflammatory mechanisms.

- IN THE TENDON SHEATHS, when the sheaths are swollen, there is a buildup of fluid that lubricates them, in addition to this the pressure it can generate, it produces deposits of substances that produce inflammation, also creates adhesions and calcifications. The drainage increase of this pathological fluid and placement in its own sheath are anti-inflammatory substances, lubricants, anticoagulants, etc., is often very beneficial and sometimes the only really effective tool.
- PERINEURALLY, trying to desensitize the regions where the pathology is chronic. We use in this case, neurolytic which are substances that moderately alter the nerve, in its sensitive portion, acting on the myelin that covers it, impeding the transmission of impulses and thereby decreasing the sensitivity.
- IN THE DENOMINATE REGIONAL BLOCKING OF THE ENDOVENOUS, where after applying a tourniquet on the distal portion of a limb, we inject medication in the vein that drains the region, preventing its return, "thus soaking the affected area with the medication that is being used and as long as we maintain a tourniquet, we thus achieve a very high concentration of antibiotics or anti-inflammatory that we would have used.

There are two frequent questions we receive when we talk about infiltrating a horse. A widespread belief is that infiltration creates dependency, and is that once we use it for the first time, we can't quit to perform it in the future.
Another widespread myth is that infiltration by definition is something harmful.
Regarding the first of the theories, dependency, we can flat-out deny it. Infiltration is used only when necessary, and to evaluate the effects obtained. If the results are good, it may well not be necessary to perform more infiltrations, or consider two or three series of treatments and after the necessary rest, the horse can be permanently cured. We will use them when appropriate and their withdrawal is possible, without creating adverse effects for the horse.
Should be used moderately, trying to combine them with the rest of the therapeutic tools and use them in moderation.
What is also common to hear is the radical opinion, completely contrary to infiltration. Citing strong phrases like "are harmful and finally we are the ones that hurt the horse." This conservative philosophy so often limits healing options or use of the horse, and in many cases, joint disease, thanks to infiltrations we achieve that a horse could continue its activity, not necessarily in high competition, but in riding, jumping, or dressage at an amateur level, walk etc. Doing one or two injections a year will keep the horse operational, in my opinion it is a valuable aid not only for the owner, but also for the horse, which would otherwise terminate its active stage as a riding or sport horse.
An important issue is the type of drugs used, the doses and how often they are used. Some substances such as hyaluronic acid, glycosaminoglycans, platelet or Medullary, are totally beneficial factors. They do not produce adverse effects and only provide nutrient factors, anti-inflammatories, lubricants and cartilage articulate protectors.
Denominate drugs like Corticoids have been classically blamed for generating an immediate beneficial gain but with major erosions of the cartilage in the long term. That is why we use it if it is necessary, but always with protectors like hyaluronic acids, in low doses and choosing the most appropriate compound.

In that situation of NOT TO BE USED:
We must contraindicate the therapy by infiltration when around the target area of affected tissue. In cases of infection, you can employ the use of antibiotics locally, infiltrating in the affected area. We must avoid analgesic infiltrations or anti-inflammatories on soft tissues. Tendons and ligaments must fundamentally heal with rest. It is only coherent the local use of growth factors, platelet or medullar's to improve the quality of tissue repair. In no case the use of these factors reduces the rest and healing time.
We avoid performing them in young horses, always trying to be as much as possible conservative with these patients.
We avoid performing them repeatedly when its benefits would be short-termed.
We avoid using them to mask pain and are able to compete with them. They are not an instrument to compete better, but to try and improve the injury or disease.
We avoid using the use of corticoids and if we do always accompanied by chondroprotectives.
We avoid using high doses, with better benefits and less damage to the joints, opting for extremely low doses, with which has been demonstrated that there may even be beneficial effects on the cartilage.
We will avoid using them if for some reason sanitary conditions could not be applied in full aseptic technique.
With all this said we are describing the reasonable and the conservative criteria for its use, where they are taken into account, this technique will be a valuable assistance.
In other medicine fields, it's emerging around the world of sport and injuries, infiltrations are a very valuable instrument and often irreplaceable.
We use them in Pediatrics, septic arthritis, to combat the devastating destruction of an articulate by the effects of infection.

Washing articular infiltration in a foal with septic arthritis

We use in ophthalmology, intraocular form or subesclera in numerous cases of uveitis or in other ocular problems.

Subescleral infiltration in a case of recurrent uveitis

Used in sarcoids or in some tumor lesions, which can be infiltrated around the tumor with immunosuppressive substances or cytostatic drugs. We use them in infectious diseases, sometimes in difficult places to access, such as the infiltration in a subdural space, intracranial and the (C1) first cervical vertebra, to treat tetanus, or some types of meningitis. Finally, we can conclude that infiltrations are a medical tool, which used with wisdom are very helpful. That its use can be detrimental in some cases and highly beneficial in others, it's only a way of administering medication, and that the important thing to decide is, will it be a precise indication, the substances to be used, the frequency of repetition, and respect for the patient.