Neurosurgeon Dr. Petar Ilkov in front of FACTI: The peak of disc herniation is between 30 and 50 years

Low back pain is among the most common complaints, but not every pain or numbness in the leg means a disc herniation. How does the disease appear, which are the most commonly affected parts of the spine, when can treatment be done without surgery and in which cases surgical intervention becomes necessary? These and other questions are answered in front of FACTI by Dr. Petar Ilkov, head of the Spinal Neurosurgery Unit at the Neurosurgery Clinic of the University Hospital of Medical Sciences “N. I. Pirogov“ – Sofia.

- Dr. Ilkov, lower back pain and burning pain along the nerve in the leg – is this a disc herniation? Why and how does it occur?
- It is possible, but not every pain in the lower back or leg is a herniated disc. The typical picture is pain in the lower back that spreads to the buttocks and down the leg, often with burning, tingling or weakness. This is the so-called radicular pain – when disc material irritates or compresses a nerve root.
The intervertebral disc is a kind of shock absorber between the vertebrae. With age and under the influence of heredity, repetitive stress, smoking, overweight and immobilization, it gradually loses elasticity. Cracks can appear in its outer layer and part of its softer inner structure can shift outward. This does not necessarily happen after one specific heavy lifting – often it is the last moment of a longer degenerative process.

- Where and on which vertebrae does a herniated disc most often occur and why?
- Most often, a herniated disc is in the lumbar region – at the levels L4–L5 and L5–S1. These are the most mobile segments of the lower back and take on a large part of the mechanical load when walking, bending, sitting and lifting weights. In second place, hernias appear in the cervical region, where they cause pain and numbness in the arm, and most often C5–C6 and C6–C7 are affected for similar reasons. In the thoracic region, herniation is rare — less than 1% of all — because the rib cage stabilizes the segments and limits movement.

- How common is lumbar disc herniation?
- Different studies define it differently - some count leg pain, others image-confirmed herniation, and still others operate. Pain along the course of the sciatic nerve at least once in their lives is reported by between 13% and 40% of adults, depending on the definition. Clinically significant symptomatic lumbar disc herniation affects approximately 1-3% of people at some point in their lives and is among the most common causes of pain "going down" the leg. The peak of disc herniation is between 30 and 50 years - that is, in the most active working age. This is not a disease of old age, in a 70-year-old person, the cause of leg pain is more often stenosis, not herniation. It is important, however, that MRI often shows disc changes even in people without any complaints. That is why we do not treat only the image, but compare the imaging study with the symptoms and the neurological examination.

- How is a herniated disc treated and when is surgery necessary?
- In most cases, the initial treatment is non-surgical: a short period of gentle treatment, painkillers and anti-inflammatory drugs, early movement according to tolerance and the gradual inclusion of appropriate rehabilitation. In carefully selected cases, a blockade can also be applied to temporarily control severe radicular pain.
We consider surgery when there is increasing or significant muscle weakness, unbearable pain that does not respond sufficiently to adequate treatment, or when the symptoms persist and clearly correspond to the MRI finding. Emergency surgery is necessary for disorders of urinary or bowel control, numbness in the buttocks and between the legs, or rapidly progressive weakness in the leg.

- What does the surgery involve and how long does recovery take?
- Most often, a microdiscectomy is performed - through a small incision, under optical magnification, only the part of the disc that is pressing on the nerve is removed. The goal is not to "remove the entire disc", but to safely release the nerve root while preserving the normal structures as much as possible.
In an uncomplicated case, the surgery usually lasts about 45-90 minutes. The patient is able to move around the same day or the next, and the hospital stay is usually short. Returning to light, office work is often possible after 2-4 weeks, and to heavy physical labor - after at least 6-8 weeks, depending on the specific case. Leg pain usually subsides quickly; numbness or weakness may take months to recover.

- When is surgery to remove the hernia alone sufficient and when is fixation with implants necessary?
- In the case of a first, typical disc herniation without spinal instability, it is most often sufficient to simply remove the hernia and release the nerve. Placing screws and implants is not a "safer" or mandatory addition.
We discuss fixation and fusion of the vertebrae only for specific indications: proven instability or slippage of a vertebra, deformation, severely destroyed disc with pronounced mechanical pain in the lower back, or when so much of the joint structures must be removed to release the nerve that the segment would become unstable. Even repeated disc herniation in itself does not automatically mean the need for implants.

- Does the pain completely disappear after surgery?
- The most predictable response is to the leg pain caused by the pinched nerve. In properly selected patients, it often decreases significantly in the first few days. Back pain is a more complex symptom: it can come not only from the disc, but also from the joints, muscles and general degeneration of the spine. Therefore, no responsible surgeon should promise that every pain will disappear completely.
If the nerve has been compressed for a long time, residual numbness, burning or weakness may recover slowly and sometimes incompletely. This is why a consultation should not be postponed in the event of a progressive neurological deficit.

- How likely is it that the hernia will reappear after surgery?
- A recurrent herniation at the same location is observed on average in about 5% of operated patients, with published rates varying greatly between different studies. The risk depends on the condition of the disc itself, the size of the defect in it, smoking, obesity, diabetes and the nature of the loads. The operation removes the compression of the nerve, but cannot make the disc completely healthy again. This is why a sensible return to activity and long-term care of general health are important after recovery.

- Every spine undergoes natural degeneration over time. How can we protect ourselves?
- We cannot stop the natural aging of the discs, nor can we change the genetic predisposition. However, we can reduce unnecessary stress and keep the spine functional. The most beneficial are regular movement, exercises for strength and control of the muscles of the back, abdomen and pelvis, maintaining a normal weight and quitting smoking. When working at a desk, it is good to have frequent short breaks and change posture, instead of prolonged immobile sitting. When lifting weights, the load should be close to the body, with the participation of the legs, and not with sudden bending and twisting at the waist.
There is no magic posture, belt or nutritional supplement that is guaranteed to prevent a herniated disc. The best strategy is constant, reasonable physical activity and timely consultation in case of pain that spreads to a limb, numbness or weakness.
And finally, something that as a neurosurgeon I consider essential - do not get an MRI without an indication. The image will almost certainly show something. This is normal for age in most cases, but once seen, it causes anxiety, activity restriction and sometimes unnecessary treatment. Imaging is done when its answer will change the doctor's behavior — not for reassurance.
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Dr. Petar Ilkov is a specialist in neurosurgery and head of the spinal neurosurgery unit at the Clinic of Neurosurgery of the University Hospital “N. I. Pirogov“ – Sofia.
His professional interests and practice are focused on spinal surgery, including minimally invasive and percutaneous techniques, navigation and robot-assisted implant placement, as well as neuro-oncology and neurotraumatology. He has obtained an educational and scientific degree of “doctor“ with a dissertation in the field of minimally invasive transpedicular stabilization. He has completed international courses and specializations in the field of spinal neurosurgery.
He is a member of the Bulgarian Society of Neurosurgery, the European Association of Neurosurgical Societies (EANS) and AO Spine. He actively participates in professional congresses and scientific and educational forums. He also examines at the "Neurovita" MC.