The intervertebral disc is a hydrodynamic system deputed for absorption of shock and anatomically composed of three parts, the fibrous ring, the nucleus pulposis and the articular cartilage. The first two zones allow the disc to function as a shock absorber and to resist the forces of traction and torsion. For that purpose, the nucleus pulposis, included in the annulus fibrosus, consists of a high concentration of water, proteoglycans and collagen.

The migration of the nucleus pulposis through the fibers of the annulus and its eventual migration outside, causes herniated disc and involve a mechanical compression of neural structures. An inflammatory reaction with release of various biochemical factors (prostaglandins, leukotriene’s, etc…) is supposed to be associated with this pathology.

The displacement of the disc material can happen at the center or, more commonly, laterally. Lateral disc herniation is a common cause of sciatica with leg pain (lumbar radiculopathy). Lumbar disc herniation most commonly is located between the fourth and fifth lumbar vertebrae, and between the fifth lumbar and first sacral vertebrae. These levels are also called L4/L5 and L5/S1 and are considered to constitute more than 90% of lumbar disc herniation (Figure 1) [1].

Figure 1: Normal and herniated disc material.

Many studies have suggested the possibility that the pain is mainly due to an inflammatory reaction by extrusion of the nucleus pulpous and not by mechanical compression on the nerve. Ozone has both the ability to act on the transformation of the herniated nucleus and to block the pro-inflammatory factors.

On October 2009, a Caucasian woman of 44 years, reports right lumbosciatica. Physical examination detects the VAS 7/10, discrete motor deficits (the patient cannot stand on the tip of the right foot) and the absence of Achilles and right plantar reflex. Spinal MRI shows extruded right hernia L5-S1, with compression on the S1 root.

The patient decides to submit to a cycle of Oxygen-ozone therapy, including 12 intramuscular paravertebral infiltrations L5/S1, with biweekly frequency, of gaseous oxygen-ozone mixture with a concentration of 20 μg/ml as this is the typical indication for ozone therapy. The therapy, however, gave rise to a moderate remission of pain but not of the motor deficit, so decided for neurosurgical advice and is given indication for surgical treatment.

The surgery resolved the symptoms and the patient were discharged on the third day without motor deficits. During the intervention fragments of the L5-S1 disc were collected and were examined histologically to study of the structure of collagen fibers by the Laboratory of University “Sapienza” of Rome.

The therapeutic approach to the clinical syndrome caused by slipped disc has been widely debated as well as the possible complications that can arise from the use of various therapeutic techniques. The therapeutic efficacy of oxygen-ozone therapy in the treatment of disk-root conflicts from herniated discs has been known for several years [2,3]. Our clinical experience investigated, in this case report, the histological changes that took place in the herniated disc tissue, after a cycle of oxygen ozone therapy. The histological evaluation of the intervertebral disc tissue after treatment shows the absence of inflammatory reaction, the loss of water and the proteoglycans associated with an increase of collagen fibers.

Some authors suggest that the success of the oxygen-ozone therapy in the treatment of herniated discs is attributable to action decompressed action of ozone, in fact, the dehydration of herniated nucleus pulpous or compressing of the bundles of annulus fibrosus would reduce the pressure on the nerve roots and bone. Slight modifications of the volume of the rigid vertebral canal are able to generate significant modifications of pressure. Total absence of inflammatory findings during histological examination confirms how the inflammatory reaction that is created between the nucleus pulposis and the nerve root could be effectively neutralized by ozone that has proven ability to regulate the pro-inflammatory cascade. A lot of studies [4,5] show that ozone has a strong healing action and profibrotic, and therefore, a progressive fibrotic action on the hernia, highlighted by the histological analysis. This treatment may restrict or block production of pro-inflammatory substances from the hernia itself on the one hand and on the other to form a mechanical reinforcement avoiding herniation of the "nuclear" material that still remained non-fibrotic.

Comparing the histological changes of the oxygen-ozone treated hernia to another one normally treated, it confirms fibrotic change of nucleus pulpous treated with oxygen-ozone without reduction of volume. Never the less these patients showed a significant remission of symptoms. The action of oxygen-ozone is performed in a major development of fibrous tissue of disc herniation. This would prevent the production of pro-inflammatory substances by the hernia itself, thus explaining the disappearance of the painful symptoms in the absence of volumetric reduction of the hernia.

Therefore, the now consolidated model of cause of pain due to nerve root compression should be revised.

Learning points

The intervertebral disc supports movements and impacts of the body and the displacement of the disc material causes an inflammatory reaction.

Herniated disc material involves a mechanical compression of neural structures inducing motor deficits.

Oxygen-ozone therapy restricts production of pro-inflammatory substances from the hernia, which is the responsible for the painful symptoms and restricted body movement.