Herniated disc: symptoms, treatment and when to operate

What the intervertebral disc is

Between one vertebra and the next there is a disc that acts as a shock absorber and allows the spine to bend and rotate. It is made up of an outer annulus fibrosus , made of layers of criss-crossing fibres, and an inner nucleus pulposus , which is gel-like and rich in water. Behind the disc runs the spinal canal, from which the nerve roots leading to the legs emerge (Figure 1).

How a herniation forms

With age the disc loses water and the annulus can tear. Under load, part of the nucleus pushes outwards. International nomenclature distinguishes three main forms [7]:

• Protrusion: the disc bulges beyond its margin with a broad base; the annulus still contains it.
• Extrusion (expelled herniation): the material passes through the tear and its outer part is wider than the “neck” it came out of.
• Sequestration (migrated herniation): a fragment breaks away completely from the disc and can move up or down within the canal.

Pain does not depend only on mechanical compression: the nucleus material also causesinflammation of the nerve root. This is why a small herniation can be very painful and a large one, at times, almost painless.

Symptoms: they depend on which nerve root is involved

Lumbar disc herniation mainly affects the L4-L5 and L5-S1 [6]levels. The typical symptom is sciatica: pain that runs from the back or buttock down the leg, often stronger than the back pain itself, and gets worse when sitting, coughing or sneezing.

Cervical disc herniation. In the neck, a herniation causes pain radiating into the arm (cervicobrachialgia), with tingling in the fingers. The root most often involved is C7 (middle finger, triceps), followed by C6 (thumb, biceps) [11]. In a population-based study, years later 90% of people had no symptoms or only mild complaints [11]. Clumsiness when using the hands or an unsteady gait may indicate that the spinal cord is under strain (myelopathy) and require a prompt consultation. Read more: cervicobrachialgia.

When to go straight to the Emergency Department

How it is diagnosed

Diagnosis starts with the clinical examination: the description of symptoms, the straight-leg raise test (Lasègue), reflexes, strength and sensation show which nerve root is involved. Magnetic resonance imaging (MRI) is the reference test when symptoms are consistent with radiculopathy [3]: it confirms the herniation and shows its size and position (Figure 4). CT and electromyography are used in selected cases. Without warning signs, an MRI is not always needed straight away: it is requested if symptoms do not improve or if an injection or surgery is being considered.

A word of caution about reports. In a study of 98 people without back pain, 52% had a disc bulge, 27% a protrusion and 1% an extrusion [8]. A review of 3,110 pain-free people found protrusions in 29% of people in their twenties and 43% of those in their eighties [9]. A “herniation” on a report therefore matters only if it matches the symptoms and the clinical examination.

Does a herniation reabsorb on its own?

Often, yes. The immune system recognises the material that has come out of the disc as foreign and gradually “clears it away”. A systematic review calculated spontaneous regression in 96% of migrated herniations, in 70% of extruded herniations, in 41% of protrusions and in 13% of simple bulges; complete resolution occurred in 43% of sequestrations and 15% of extrusions [4]. The largest herniations, those that have “come out”, are therefore not necessarily the worst.

Can it heal without surgery?

Yes, in most cases. Conservative treatment includes:

• Information and movement: staying active within the limits of pain; prolonged bed rest does not help and weakens the muscles.
• Medication: painkillers and anti-inflammatories, as prescribed by the doctor and for as long as needed.
• Physiotherapy: personalised exercises to control pain, recover movement and strengthen the trunk.
• Injections: in selected cases, cortisone injected near the nerve root (epidural or periradicular, under imaging guidance) can provide short-term relief [3].

When surgery is considered

Surgery is recommended in case of significant or worsening loss of strength, cauda equina syndrome or disabling leg pain that does not improve after about 6–12 weeks of well-conducted treatment, with an MRI that matches the symptoms.

What the most important studies say:

• In the Dutch study published in the New England Journal of Medicine, patients operated on early had faster relief from leg pain; at one year, however, the likelihood of feeling recovered was 95% in both groups. In the conservative group, 39% eventually had surgery over time [2].
• In the American SPORT study, both groups improved substantially [1]; at 8 years, those who had surgery showed greater improvement, with stable results over time in both groups [12].

The decision is therefore not “dictated” by the image: it is made together with the patient, based on the intensity of the pain, their work, their expectations and how quickly they wish to return to normal life.

How microdiscectomy works

The most common operation is microdiscectomy: through a small incision and using a microscope, a small window is opened in the bone, the nerve root is gently moved aside and only the fragment compressing it is removed. The rest of the disc stays in place and no screws are inserted (Figure 5). In selected cases Dr. Lavanga usesbiportal spinal endoscopy, through two small incisions.

Endoscopic techniques have been compared with traditional microdiscectomy: in a randomised trial of 613 patients, transforaminal endoscopy proved non-inferior, with less blood loss, a shorter hospital stay and earlier mobilisation [13].

Recovery after surgery

• Same day or next day: you get up and walk; leg pain usually eases within the first few days, while tingling and strength may take weeks or months to recover.
• First weeks: daily walks of increasing length, avoiding lifting heavy objects and sitting for long periods.
• Work and sport: desk jobs are usually resumed earlier than physically demanding ones; timing is agreed at the follow-up consultation.
• Physiotherapy: a trunk-strengthening programme with the Ortho-Next physiotherapists supports a gradual return to activities.

Can the herniation come back?

In a minority of cases, yes. In the Dutch randomised trial on endoscopy, a repeat operation was needed within one year in 5–6% of patients, with similar results for the two techniques [13]. Weight control, trunk strengthening and a gradual return to loading help reduce the risk. For repeated recurrences, or when a worn disc is combined with a failing segment, alumbar spinal fusionmay be considered, for example with the TLIF technique.

Prevention

Regular physical activity, frequent breaks from sitting, correct lifting technique (straight back, load close to the body, power from the legs), maintaining a healthy weight and stopping smoking all support disc health and reduce the risk of relapse.