Sural nerve pain is debilitating pain in the lower outer calf and foot. Generally, we see sural nerve pain from trauma or entrapment of the sural nerve as it passes down the calf into the foot. What is sural nerve pain, how do we diagnose it, and what is the best treatment?
What is the sural nerve?
The sural nerve starts at the outer top part of the lower leg and travels down the calf close to the Achilles tendon. It winds around the outer part of the ankle (also called the lateral malleolus) to end at the outer part of the foot. It provides sensation (such as light touch) from the outer part of the lower leg to the outer part of the heel, ankle and foot.
Causes of sural nerve entrapment
Damage to the sural nerve can occur due
- direct trauma such as a hit or fall onto the outer lower leg or calf
- fractures or sprains of the ankle leading to damage to the sural nerve as it passes close to the outer ankle
- trauma from recent surgery such as Achilles tendon repair or metalwork. Sural nerve damage has been reported in up to 25% of all Achilles tendon repairs performed percutaneously.
- tight-fitting shoes or boots that compress the sural nerve causing swelling
- lumps such as ganglions, more commonly around the ankle
Symptoms of sural nerve entrapment
Often, sural nerve damage leads to pain in the outer lower leg. Generally, pain is burning but could also be sharp shooting. Sometimes, pain radiates down into the outer part of the foot or up into the top part of the calf. Sural nerve pain can be present at rest and worsened by activity such as fast walking or running. Also, sitting or driving can worsen symptoms by increasing the tendon on the sural nerve.
How to diagnose
People with sural nerve irritation have sensitivity to touch at the outer part of the calf and lower leg. Tapping the nerve at the trapping site will often cause a sharp. Your doctor will examine your calf and foot for evidence of sensitivity along the sural nerve. Other helpful tests include neural stretching tests such as slump or straight leg raise tests.
Your doctor must exclude other causes of pain in the outer calf and foot, such as referred pain from the spine, calf tears, ankle joint sprains or fractures, and peroneal or Achilles tendonitis.
Investigations can help diagnose sural nerve pain. MRI scan might show inflammation of the nerve at the site of damage. However, most causes of sural nerve pain don’t demonstrate clear signs of inflammation and may be reported as normal. Generally, ultrasound is more useful as you can carefully follow the course of the nerve from the calf, looking for signs of nerve inflammation or trapping. Usually, nerve damage on ultrasound is seen as sudden nerve thickening at the trapping site.
Sural nerve pain treatment
Exercises to relieve sural nerve pain
Frequently, if we suspect sural nerve pain, we recommend simple treatments such as ankle and foot joint mobilisation, soft tissue therapy to the tender areas and appropriate footwear to reduce pressure on the nerve. Simple nerve stretches, or sural nerve gliders, help loosen the nerve and reduce irritation. Also, gentle calf, hamstring and pelvic stretching will help.
Certain topical and oral medications can help sural nerve pain. Rubbing anti-inflammatory creams such as Volatrol or Feldene cream at the site of tenderness will reduce nerve swelling and relieve pain. Medications such as amitriptyline or duloxetine used to treat nerve pain can make the sural nerve less painful and intense. However, these medications can only be prescribed by a doctor and have side effects.
Ultrasound-guided cortisone injeciton
In some cases of sural nerve trapping, a cortisone injection directed to the site of trapping will improve symptoms. This procedure must be performed with ultrasound guidance to improve accuracy and effectiveness.
Finally, surgical release or decompression of the nerve may be needed in cases that fail all other treatments. One study found mixed results are surgical excision of neuroma and re-implantation.
Final word from Sportdoctorlondon about sural nerve entrapment
Sural nerve pain is an uncommon cause of outer calf and foot pain, often caused by trapping or nerve irritation from a recent injury or surgery. You should see a doctor skilled in diagnosing this condition. Often, ultrasound expertise helps find the site of trapping and may help direct a cortisone injection if needed.
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