The human spine consists of 24 vertebrae connected by intervertebral discs. The basic function of the discs is to provide the flexibility that allows movement between the vertebrae while maintaining the sufficient strength of their connection. When there is a burden on the spine, all the discs (especially the lumbar discs) have to resist large forces (loads can be up to 700 kg while bending) while permitting smooth movements (bending backwards, bending forwards, and also while rotating).
The centre of the disc is made up of matter remotely similar to gelatine that surrounds the perimeter of the hard fibrous ring, and is bound to the surrounding vertebrae by a cartilage transitional layer. Intervertebral discs have no blood supply – they are the largest areas in the body where blood vessels do not go. The discs absorb all their nutrients from their surroundings. At night, when we lie down and put no pressure on our backs, the discs soak up fluids and swell up. During the day, as the back is burdened, the fluid is squeezed out. People are about 1 cm taller in the morning than in the evening. The discs are deformed during the day as the back moves around, together with the repeated exrtrusion and absorbtion and this mechanism the exchange of nutrients and oxygen is supported.
As life goes by the discs gradually get worn out. Signs of this process are already visible on specialized image screening (magnetic resonance) on people of around 20 years old. In some people a number of influences (inherited, movement, lifestyle, smoking etc.) cause the ageing process of these discs to be accelerated, they become worn out more quickly and finally their structure and function can fail. In the context of this acceleration, the hard ring can rupture and the core material can be squeezed out of the disc. This usually occurs while bending under a burden, but it can happen without any apparent cause. The herniated core mass puts pressure on the nerve structures located in the spinal canal. Sciatic nerve compression occurs most frequently, and is felt as a severe pain.
Information from the leg (sensitivity, pain) goes through the nerve roots to the spinal cord and then on to the brain, and information from the brain goes back to the muscles (movement) If the nerve is irritated, the patient feels it as pain in the lower limb. If the root is significantly compressed, then deterioration of sensitivity and weakening of the muscles, that is movement, are added to the pain. In the most severe cases a large number of roots are compressed (Cauda equina syndrome), where besides pain, insensitivity and weakening of the lower limbs the patient has similar symptoms in the genital areaand cannot hold urine or faeces. These cases must be operated on urgently.
In the event that a disc herniates, there is a chance that the body will react and absorb the herniate. If the patient is in pain, but does not have impaired sensitivity and strength, it is usual to wait and treat them with infusions, painkillers (analgesics) and rehabilitation with the aim of relieving pain until the herniate absorbs itself. This treatment works well for a large number of patients and removes their problem. If the pain persists, or if painful periods repeat often, then an operation is required. In cases when the nerve roots are severely compressed, the patient loses feeling in their legs, which are weakened, a timely operation is required to prevent permanent disability. The herniated disc material is removed and the compressed nerve root is relieved. As well as correcting the patient’s condition, this operation has a preventative significance. If root compression lasts too long it can lead to permanent results even after a successful operation, either in the form of permanent pain, or permanent impairment to sensitivity and movement.
In earlier times “lumbago” was treated using various methods. However, the nature of the disease meant that people had this illness repeatedly and with more severe forms often suffered permanent consequences and even full invalidity and movement restricted to a wheelchair. The introduction of surgery has significantly improved the overall course of the disease and prevents severe permanent consequences.
Correctly indicated and conducted operations, however, do not only affect the purely medical aspects. Repeated “lumbagos” and lengthy sick-leave in today’s demanding society significantly reduce the position of an otherwise capable person on the labour market. Long-term difficulties have financial and psychological effects, and in time can become manifest in personal relations in the patient’s family, areas of interest and professional circle. All these factors need to be taken into account both before and after the procedure is performed. Correcting the patient’s condition is a prerequisite for resolving these issues, but often the situation is the other way around, so that correcting these issues is a prerequisite for curing backache.