Sciatic Nerve Injury

Overview

The sciatic nerve is the largest and longest nerve in the body. It begins in the lower back, passes deep through the buttock, and runs down the back of the thigh before dividing behind the knee into branches that supply the lower leg and foot. A sciatic nerve injury is direct damage to this nerve, which disrupts the signals that control movement and sensation in much of the leg.

This is different from sciatica, a term usually used for irritation of the nerve roots in the spine (for example by a herniated disc). A true sciatic nerve injury involves the nerve itself further along its course and may follow surgery, an injection, a fracture, or other trauma. Recovery can be slow because nerves regrow only gradually, but many injuries improve with time and rehabilitation.

Symptoms

Symptoms depend on how badly the nerve is damaged and where along its path the injury occurs. They typically affect one leg.

• Sharp, burning, or electric-shock pain running down the back of the leg
• Weakness in the leg or foot, including difficulty lifting the foot ("foot drop")
• Numbness or reduced sensation in the back of the leg, the outer lower leg, or the foot
• Tingling or "pins and needles"
• Difficulty walking, frequent tripping, or an unsteady gait
• Muscle wasting in the leg over time if the injury is severe

Because the nerve carries both movement and sensation, an injury can cause a mix of weakness and altered feeling. Loss of sensation can also make the foot vulnerable to unnoticed injuries.

Causes

The sciatic nerve can be injured by anything that stretches, compresses, cuts, or bruises it. Common causes include:

• Hip and pelvic surgery: The nerve can be stretched or compressed during hip replacement or other procedures.
• Injections: An incorrectly placed injection into the buttock can damage the nerve.
• Fractures and dislocations: A broken pelvis, hip dislocation, or thigh-bone fracture can tear or compress the nerve.
• Direct trauma: Penetrating wounds, deep cuts, or a hard blow to the buttock or thigh.
• Prolonged pressure: Sitting on a hard surface for very long periods or pressure during a long operation or period of immobility.

Less commonly, tumors, infections, or bleeding near the nerve can also be responsible.

Risk Factors

• Major hip or pelvic surgery
• Pelvic, hip, or thigh-bone fractures and dislocations
• Conditions that make nerves more fragile, such as diabetes
• Prolonged immobility or pressure during illness or surgery
• High-energy trauma such as road collisions or falls

Diagnosis

Diagnosis starts with a careful history and a physical examination that tests strength, reflexes, and sensation in the leg. To confirm the injury and judge its severity, doctors may use:

• Nerve conduction studies and electromyography (EMG): Tests that measure how well electrical signals travel through the nerve and reach the muscles.
• Imaging: MRI or ultrasound to look at the nerve and surrounding structures, and X-rays or CT to assess nearby fractures.

These tests help distinguish a sciatic nerve injury from spinal causes such as a herniated disc or spinal stenosis, and guide whether the nerve is likely to recover on its own.

Treatment

Treatment depends on the cause and severity. Many injuries that bruise or stretch the nerve without cutting it recover gradually as the nerve heals.

• Physical therapy: Exercises to maintain strength and range of motion, prevent stiffness, and retrain walking.
• Pain management: Medications for nerve pain, along with other measures to keep the person comfortable.
• Bracing: An ankle-foot orthosis can support a foot that drops, improving walking and reducing falls.
• Treating the cause: Stabilizing a fracture, relieving pressure, or removing a mass pressing on the nerve.
• Surgery: If the nerve is cut or trapped, surgical repair, decompression, or grafting may be considered, ideally before long-term muscle wasting sets in.

Nerves regrow slowly, often over many months, so recovery and rehabilitation can take a long time.

Prevention

• Ensure injections into the buttock are given correctly by trained staff
• Use careful positioning and padding during long surgeries and periods of immobility
• Protect the foot and skin from injury when sensation is reduced
• Follow rehabilitation advice closely after hip or pelvic surgery
• Manage conditions such as diabetes that make nerves more vulnerable

When to See a Doctor

See a doctor promptly if you develop new leg weakness, numbness, or difficulty lifting your foot, especially after surgery, an injection, or an injury. Seek emergency care if you have:

• Sudden, severe leg weakness or inability to move the foot after trauma
• Loss of bladder or bowel control, which may signal a serious spinal problem
• Numbness in both legs or around the groin
• A wound, deep cut, or fracture with new loss of feeling or movement in the leg

Related Topics

Frequently Asked Questions

References

1. MedlinePlus, U.S. National Library of Medicine. Peripheral nerve disorders.
2. National Institute of Neurological Disorders and Stroke (NINDS). Peripheral Neuropathy.
3. Mayo Clinic. Sciatica — Symptoms and causes.
4. American Academy of Orthopaedic Surgeons (AAOS). Peripheral nerve injuries.