Lumbar disc herniation is a consequence of degeneration (normal aging) of the lumbar intervertebral disc. Part of the disc may protrude back into the lumbar vertebral canal, through which the nerve roots of the lower limbs travel. Below: a drawing representing three different types of lumbar disc herniation. We can see the fibrous annulus (in blue) through which a fragment of the disc nucleus has extruded.
Several MRI studies have shown that lumbar disc herniations are very common in the normal asymptomatic population. Sometimes a herniated disc can cause radicular pain: an inflammatory or mechanical irritation of a nerve root in the lumbar spine. Depending on the location, this can be sciatica (pain typically starting from the buttock, then behind the thigh and calf to the foot), or cruralgia (pain in the anterior aspect of the thigh stopping at the knee). Sciatica is more common than cruralgia, and it is caused by an L4-L5 or L5-S1 hernia.
The vast majority of sciatica or cruralgia are treated non-surgically, because they present without severity criteria. These are: the loss of strength of more than 50% or a cauda equina syndrome (a rare neurologic injury, but serious with urinary and faecal sphincter incompetence). The specialized spine surgeon will be solicited in case of: disabling neurologic deficit (loss of strength> 50% or other serious neurological damage), or persistent pain (sciatica or cruralgia) despite maximum non-surgical treatment or more than 6 weeks without effect.
The natural course of lumbar disc herniations shows that pain symptoms resolve on average after 6 to 8 weeks, almost spontaneously. Non-surgical treatment accompanies this natural evolution by relieving pain with: anti-inflammatories, myo-relaxants, physiotherapy, osteopathy, sometimes injections in the spine, etc.
Light neurologic deficits (loss of strength, tingling, decreased sensitivity) recover in a few weeks.
The surgery involves removing the hernia that irritates the nerve root. For this, the most common technique, and “gold-standard”, is the microscopic herniectomy: small incision in the back and use of a microscope and small instruments to remove the hernia (see schematic representation below) . Only the fragment is removed, the goal being to injury as little as possible the rest of the disc. The intervention lasts between 30 minutes and 1 hour.
Patients remain hospitalized for at least one night for surveillance. They resume walking the same day of the surgery. Sciatica or cruralgia pain usually improves immediately after surgery. Sensory and motor deficits (loss of strength) may take longer to recover.
The risks associated with this surgery include general risks and more specific risks such as the dural breach. The risk of serious neurological complications is very low (close to 0%). More information will be given by the surgeon before the procedure.