ConditionBrain & nerves
Sciatic Nerve Injury
A sciatic nerve injury is damage to the sciatic nerve itself, the largest nerve in the body, which runs from the lower back through the buttock and down the back of the thigh to the leg and foot. It differs from common sciatica, which comes from a pinched nerve root in the spine. Injury can follow hip replacement surgery, hip fractures and dislocations, misplaced buttock injections, deep wounds or prolonged pressure. It causes weakness below the knee, foot drop, numbness and burning pain. Recovery is slow and depends on how badly the nerve is damaged.
Also called: Sciatic neuropathy, sciatic nerve palsy, sciatic nerve damage, sciatic mononeuropathy
At a glance
- What it is
- Damage to the sciatic nerve trunk in the pelvis, buttock or thigh, rather than a pinched root in the spine.
- Causes
- Hip replacement and hip surgery, hip fractures and dislocations, buttock injections, gunshot or knife wounds, prolonged pressure while unconscious, and tumors.
- Symptoms
- Weak ankle and toe movements, foot drop, numbness of the lower leg and foot, and burning pain.
- Diagnosis
- Nerve conduction studies and EMG, MRI or ultrasound of the nerve.
- Treatment
- Ankle-foot orthosis, physical therapy, nerve pain medicines, and surgery for cut or compressed nerves.
When to get help
Call 911 or go to the ER
- Sudden leg weakness with numbness between the legs or loss of bladder or bowel control (possible cauda equina syndrome): call 911
- Severe buttock or thigh pain with tense swelling after injury or surgery (possible compartment syndrome or hematoma)
- A deep wound to the buttock or back of the thigh with leg weakness
See a doctor within a day or two
- New foot drop or leg numbness after hip surgery, a hip injury or an injection in the buttock
- Leg weakness and burning pain after being unconscious or immobile for a long time
- Rapidly worsening leg weakness
Book a routine appointment
- Foot drop or numbness in the foot that is not improving after several weeks
- Ongoing burning nerve pain in the leg
Anatomy of the sciatic nerve
The sciatic nerve forms from nerve roots in the lower back (L4 to S3). It leaves the pelvis through the sciatic notch, usually passing beneath the piriformis muscle, travels down the back of the thigh, and divides above the knee into:
- the tibial nerve, which controls calf muscles and feeling on the sole
- the common peroneal (fibular) nerve, which lifts the foot and toes and supplies feeling on the top of the foot and outer leg
The peroneal division is more vulnerable to injury, which is why foot drop is the most common sign.
Sciatic nerve injury vs sciatica
| Sciatic nerve injury | Sciatica | |
|---|---|---|
| Where the problem is | The nerve trunk in the pelvis, buttock or thigh | A nerve root in the lower spine |
| Common cause | Surgery, trauma, injections, pressure | Herniated disc, spinal stenosis |
| Back pain | Usually absent | Common |
| Weakness | Often marked, especially foot drop | Usually mild |
| Diagnosis | Nerve studies, nerve imaging | MRI of the lower spine |
Causes
- hip replacement and hip surgery: stretching, compression or direct injury during surgery, especially with hip dysplasia or leg lengthening. It affects a small percentage of hip replacements
- hip fractures and posterior hip dislocations, which can stretch or compress the nerve. See hip dislocation
- buttock injections placed too close to the nerve
- penetrating wounds: gunshots and stabbings
- prolonged pressure: lying or sitting for long periods, for example during drug overdose, coma or prolonged surgery
- compartment syndrome of the buttock or thigh
- masses: tumors, cysts, aneurysms or hematomas, especially in people on blood thinners
- piriformis syndrome: compression by the piriformis muscle, a debated and uncommon cause
- endometriosis of the sciatic nerve, causing cyclical symptoms
Symptoms
- foot drop: inability to lift the front of the foot, causing tripping and a high-stepping gait. See foot drop
- weakness pointing the foot down, bending the knee or moving the toes
- numbness and tingling of the lower leg and foot, sparing the inner calf (supplied by a different nerve)
- burning, electric or shooting pain in the leg and foot
- reduced ankle reflex
- muscle wasting in the calf over time
Diagnosis
- examination of strength, sensation and reflexes to map which branches are involved
- nerve conduction studies and EMG, ideally 3 to 4 weeks after injury, to locate and grade the damage and to track recovery
- MRI of the pelvis and thigh or high-resolution ultrasound to look at the nerve, compressing masses or hematomas
- MRI of the spine to exclude a root problem
- blood tests if a generalized peripheral neuropathy is suspected
Treatment
Non-surgical
- ankle-foot orthosis (AFO): a brace that holds the foot up and prevents tripping
- physical therapy: maintaining range of motion, preventing contractures and strengthening muscles
- nerve pain medicines: gabapentin, pregabalin, duloxetine or amitriptyline, prescribed by a doctor
- protecting numb skin from pressure sores and injury
- treating the cause, such as draining a hematoma or adjusting a hip implant
Surgical
- exploration and decompression if a hematoma, scar or mass is compressing the nerve
- nerve repair or grafting for a cut nerve, ideally early
- nerve or tendon transfers, such as moving a working tendon to restore ankle lifting when recovery is incomplete
Recovery
Nerves regrow slowly, at about 1 mm a day (roughly an inch a month), and the sciatic nerve is long, so recovery can take many months to 2 years. Outcomes depend on the severity:
- mild injuries (stretch or compression without fiber loss) often recover well within weeks to months
- more severe injuries may recover partially, with the tibial division usually recovering better than the peroneal division
- complete transection needs surgery and often leaves lasting weakness
Chronic nerve pain and complex regional pain syndrome can develop in some people and need specialist pain management.
Frequently asked questions
What are the symptoms of sciatic nerve damage?
Symptoms include weakness below the knee, foot drop with tripping, numbness and tingling in the lower leg and foot, burning or shooting pain, and a reduced ankle reflex. Muscle wasting in the calf can develop over time.
Can hip replacement damage the sciatic nerve?
Yes, though it is uncommon. The nerve can be stretched, compressed or injured during hip replacement, especially in complex cases or with leg lengthening. Most cases are partial and improve over months, but some leave lasting foot drop.
How long does a sciatic nerve injury take to heal?
Recovery depends on the severity. Mild compression injuries can improve within weeks to months, while more severe injuries may take 1 to 2 years and may not fully recover. Nerves regrow roughly an inch a month.
Is a sciatic nerve injury the same as sciatica?
No. Sciatica usually comes from a pinched nerve root in the lower spine, often from a herniated disc, and causes back and leg pain. A sciatic nerve injury damages the nerve itself in the pelvis, buttock or thigh and typically causes more weakness, such as foot drop.
What is the treatment for foot drop from sciatic nerve injury?
An ankle-foot orthosis keeps the foot lifted and prevents tripping. Physical therapy maintains movement and strength. If the nerve does not recover, surgery such as tendon or nerve transfers can restore the ability to lift the foot.
Sources
This guide was written from current patient and clinical guidance, including:
- American Association of Neuromuscular and Electrodiagnostic Medicine: Sciatic neuropathy
- American Academy of Orthopaedic Surgeons: Complications of total hip replacement
- National Institute of Neurological Disorders and Stroke: Peripheral neuropathy
- MedlinePlus: Sciatic nerve dysfunction
- Merck Manual Professional: Mononeuropathies