Nerve Blocks or Neural Blockade

INTRODUCTION

Injections are performed either to confirm a suspected diagnosis and/or reduce pain and inflammation for the patient with spinal problems or to provide relief by other mechanisms in other conditions.  These injections are often performed under fluoroscopy (x-ray) in an operating room under sterile conditions, using mild sedation (relaxation medicine) to assure proper placement of needle.

The history of nerve blocks or neural blockade in pain management dates back to 1901 when epidural injections for lumbar nerve root compression were reported.  Since then, substantial advances have been made not only in the administration of epidural injections, but a multitude of other blocks and procedures have been invented providing neural blockade a distinct place in the diagnosis and management of chronic or persistent pain.

The general benefits of the various types of nerve blocks (including epidural's and neurolytic blocks) include pain relief, which outlasts by hours, days, and sometimes weeks, the temporary pharmacological/chemical action of either the local anesthetic and/or other agents provided.  However, clear cut explanations for such benefits are not available.  It is believed that neural blockade alters or interrupts:

These explanations are based in part on the pharmacological/chemical and physical actions of the local anesthetics, corticosteroids, and other agents being used.  It is believed that local anesthetics work as follows:

The various modes of action of corticosteroids include: 

Additionally, there are certain physical or mechanical effects such as the reduction of adhesions (fibrous strands abnormally joining two parts) and scar tissue, as well as irritating chemicals released as a by-product of inflammation. 

What is Neural Blockade?

Neural blockade (oftentimes referred to as nerve blocks) is an interventional pain management procedure or technique where the physician injects a local anesthetic (similar to what your dentist does when he gives you Novacaine) to numb the pain, and sometimes an anti-inflammatory to reduce the swelling of inflamed nerves and the surrounding tissue.  By using fluoroscopy (a form of x-ray that produces an image of the internal structure of your body on a TV monitor) your doctor can place the medicine precisely where the nerve damage is located.

What is the purpose and reason for using neural blockade?

There are two purposes:  1) Diagnosis and 2) Treatment

1)         For diagnostic purposes, neural blockade is superior to any other method of determining the cause of spinal pain.  Clinical symptoms and features, imaging (x-rays, MRI, CT scan) and neuropsychological studies (EMG and Nerve Conduction) do not permit the accurate diagnosis of the true cause of spinal pain in 85% of patients who do not have a herniated disc or neurological deficiencies.  By using other means of diagnosis such as diagnostic blocks, it has been determined that in cases where there is a lock of a definite diagnosis even after x-ray, MRI, CT scan, nerve conduction and muscle testing, it is possible to identify the source of pain in the majority of patients (65-85%) as opposed to the mere 15% identified using other diagnostic methods.

2)       For treatment purposes, neural blockade (nerve blocks) is an excellent option for reducing pain due to spinal pain.  The primary source of spinal pain are damaged or deteriorated discs (the cushion/shock absorber between each vertebrae) or joints (yes, you have joints called facet joints on either side of each vertebrae to provide stability and range of motion).  Both discs and joints are easily accessible for nerve blocks.  On the contrary, surgical removal or correction of structural abnormalities oftentimes fails to cure and sometimes worsens the painful condition.  The degenerative processes of the spine and the origin of spinal pain are very complex and the effectiveness of many treatment approaches in managing chronic spinal pain has not been conclusively demonstrated.