Nervs block had  evolved imensely in the last 15 years. Started with a risky blind placement of a needle by a small group of doctors and followed by a quite high percentage of complications , the nerve block evolved in time in the hand of a large practitioners called " Interventionist ", some of the reasons for such of improvement are the introduction of a computarized X-Ray called C-Arm fluoroscope and the spreading of new and safer techniques. 
Currently with the new available tecnology, we were able to left with incredible presicion the medication around the nerve and literally "navigate"  and reach any point inside the spine. 
Contrary to the public opinion, the modern nerve blocks guided by are extremely safe and predictable . They can be used as a DIAGNOSTIC ( testing the origen of a suspected painful structure ) or THERAPEUTIC ( to cure a already know area of pain ).                   effective form to determine if the nerve or nerves are affected (diagnostic blocks), as well as to supply the medicine directly and as close as possible to the nerves or structures affected to treat them (therapeutic blockades). The blockades also receive other names as epidural procedures, " transforming injections" and selective injections (the correct name would be neuroaxial procedures).  In the last 20 years the blockades have evolved and now they are in the hands of pain specialist as they require a high level of mastery.

How do I know if I am a candidate for a Nerve block?
If you suffer of persistant pain in the spine ( neck or lower back ) of know or unknow origen and have no improvement with conservative therapy that can include Physical Therapy, rest, activity modification and have poor response to medication, should have a nerve block first to determine possible origen and second to achive a pain reduction and improve in function.

What percentage of patients they report improvement?
Approximately 70-80 percent of patients can potentially improve . As I just explained above in some conditions we test the nerve and other structures in the spine, means that no improvement can rule out certain conditions and change and re-direct the prior failed treatment.

What are some principles to have a nerve block ?
The ideal conditions for Dr Castellanos's standard is a well studied case, with a prior MRI or CT scan to locate anatomically the affected structure. Consider all potential  complications and the level of health of the patient . If the patient carried a large amount of medical conditions in Dr Castellanos opinion the nerve block should be done under monitoring and strict supervision, like Hospitals OR,  Surgical Centers (ASC) or a Register State Office Procedures Room.
The use of a high quality C-Arm digital fluoroscope can make a diference between a failure and a sucessful procedure. Remember that the lack of qualified doctor and a poor environment is a perfect recipee for a disaster, that can run from paralysis to death. 

How many blockades do I need to feel well? You should know that the blockades can be diagnoses (to find the cause) or therapeutic (where it’s already known and applied in the affected area to control the pain). Generally to confirm or find the pain two blockades are needed, in the case of treatment with a blockade it’s provided that, previously, one has responded favorably to the treatment. No scientific proof exists that there has to be three continuous applications of blockades or a determined number, it all depends on the dexterity and knowledge of the doctor. Our method is supported by prestigious organizations such as the ASIPP (Medical Interventionists of Blockades), as well as what CMS (Central of I Medicated) proposes for the correct application of the blockades. We like the fact that there exists at the least a period of six (6) months in which to apply another blockade if necessary.

What medicine does the doctor use to treat the nerve and the disks with the blockade? Over the last ten years, the doctor has investigated and developed multiple options to utilize. Traditionally he utilizes the "cortisone" or "steroid" to lower any swelling. In the opinion of the doctor, this medicine in spite of having a force, causes many collateral effects, especially in patients that are higher than 60 years old and that they suffer from diabetes, hypertension, high cholesterol, have had heart attacks, etc. For all of these patients, the doctor utilizes other substances or medicines without steroid that act similarly without causing the effects of the cortisone. All these medicines are approved by the FDA and have tested value in the case of those patients that do not require steroids or cortisone.

Are there risks with neuroaxial treatments or blockades? Each intervention of course involves a degree of risk, however you should know that the purpose of the International Pain Institute and the doctor is to minimize them. The doctor with his specialty is possibly the doctor that applies more blockades, with approximately more than 1500 in the past year; his level of mastery is the absolute highest. Nevertheless, he has had few complications or almost none. This is due to applying the scientific advances and being the head of investigations, to achieve the maximum security and positive effect in the patients.

Does that mean that different blockades exist and that each one is specific for each patient? Yes, different types of blockades exist, each one harmonious to its pathology or affection. The doctor has achieved a mastery in knowing how to apply each patient with the "ideal procedure", continuing a guide thought up by himself in reference of the affected place, the conditions of the patient, the "age of the pain or time it’s been affecting". You should know that many of the blockades fail because they do not arrive at the needed area and two conditions exist: there is the mastery of the doctor to arrive at the affected area, and the other is to know before where the problem is, otherwise the blockade is condemned to fail.