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Nerve entrapment

Upper Limb Nerve Entrapment Syndromes

Nerves are responsible for delivering your feeling and function in your arm and hand.  There are three principle nerves that reach your hand, but important branches of these nerves supply other structures in your upper limb.  Each major nerve passes through anatomically tight points on its journey to your hand.  At these points, the nerves are prone to entrapment.  If a nerve gets squashed or tethered, it’s normal function becomes interrupted. Normally this is initially intermittent and the nerve recovers, but eventually, the nerve can develop scarring and never function fully again.

There a three main nerve compression syndromes that may require surgery. Each will be covered:

  1. Carpal tunnel syndrome (median nerve)
  2. Cubital tunnel syndrome (ulna nerve)
  3. Radial tunnel syndrome (Posterior Interosseous nerve)

1. Carpal tunnel syndrome

This is very common and patients often have bilateral symptoms. Your median nerve runs along the centre of your forearm as it passes across your wrist into your hand.  Here it shares a tunnel with your finger flexor tendons. Any cause of swelling in the tunnel can compress your nerve. Symptoms typically include:

- Pins and needles in your thumb, index and middle finger

- Symptoms often worse and wake you at night

- Aching in your forearm

- Loss of fine touch sensation in the tips of your thumb, index and middle fingers

- Weakness of grip and certain thumb movements

Diagnosis in Carpal Tunnel Syndrome

Your symptoms and clinical examination are often highly suggestive. Nerve testing (neurophysiology) can clarify the extent of nerve dysfunction, but is sometimes normal even in the presence of convincing symptoms. This is done with you awake, takes 30 minutes and is mildly uncomfortable only  

Treatment Options in Carpal Tunnel Syndrome

If your symptoms are mild and your nerve function good, you may be successfully treated with a splint and an injection (cortisone). If your symptoms are more intrusive, or they fail to respond to an injection and splinting, you may require surgical release of your carpal tunnel

Carpal Tunnel Release

This is a day-case operation performed with you wide awake under local anaesthetic. You are given a numbing injection (this stings for about 10 seconds like a dental injection) .  Your hand is then cleaned and draped.  A tourniquet on your upper arm may be used  to minimise bleeding in the surgical field - this is normally only inflated for about 5 minutes and often does not need to be elevated at all.  After checking your surgical area is numb a 3cm incision is made over the front of your wrist. The tight ligament that is trapping your median nerve is released fully to ensure there is ample ‘breathing room’ for your nerve.  Your nerve is inspected to ensure it is free (you are welcome to look if you want!). Your wound is closed with sutures and covered with a padded dressing .

If I have bilateral symptoms should I have both done together, or one at a time?

This is very much your choice.  Most patients opt for staged surgery, with a gap of 6-12 weeks between sides.  However, it is perfectly feasible to have both sides done simultaneously (Mr Granville-Chapman had both sides done together). The advantage of bilateral surgery is reduced overall time off work, so it may work best for you if you are self-employed.  The potential disadvantage is the short-term incapacity from having both hands operated on.  

Recovery after carpal tunnel surgery (Mr Granville-Chapman has had this surgery - both sides at once - so he can tell you his experience!)

Please elevate your arm for the first 24hrs to reduce throbbing pain and swelling.  Do take regular painkillers as soon as you get home and for the first few days.  You can take down your bulky dressing on  day 3,  but should keep the small dressing over your wound and keep it dry for 10 days.   Please begin gentle finger and wrist range of movement straight away. Your stitches need to be removed at 10 days after your operation.

You can return to a desk job after a few days, and most people are safe to drive after four days to a week. Your grip will be sore and week for a while, so return to heavier jobs will take a few weeks.  The grip strength and soreness on loading the wrist will improve and, for most, this has resolved by three months.

Is carpal tunnel release successful?

Yes, and most patients report a rapid improvement in night-time symptoms and pins and needles. If you have severe carpal tunnel, with numbness and weakness, then recovery will take much longer and may well be incomplete.  

Are there any complications?

This is a well tolerated and successful operation, but some patients do experience problems:

Infection – this is uncommon and normally settles with antibiotics

Lack of benefit - This is uncommon.  Occasionally your median nerve is crushed in your neck as well, this would not be addressed by a carpal tunnel release.  It is very rare for inadequate surgical release or nerve damage to have occurred, but very occasionally revision surgery is indicated

Complex regional pain syndrome (CRPS) - A small proportion of patients develop pain, stiffness and swelling in response to injury or surgery to their hand.  This rarely happens and is usually recognised early and treated by special painkillers and desensitisation physical therapy.  Very occasionally it becomes severe and requires specialist pain doctor referral.

Aching in the wrist is common after carpal tunnel surgery as your hand adapts to the loss of the ligament that was cut.  You will also notice weakness of grip for a similar time and have soreness on loading the wrist (press-ups).  These symptoms have normally resolved by three months as the ligament heals.

Painful scar - this is a problem for a few patients, but this usually settles with massage and time.  You should begin to massage your scar (with a little moisturising cream) from three weeks after your operation.  This helps to desensitise the scar.

2. Cubital Tunnel Syndrome

Your ulna nerve is the one the you may have jolted on the inside of your elbow: it runs just behind the inside knuckle of your elbow and into the forearm. The ulna nerve runs into the hand and gives you sensation in your little and ring fingers and supplies most of the muscles in your hand.  Just behind the elbow there is a tunnel through which your nerve runs. This can get tight, or your nerve can be unstable and flip out of position when you bend your arm. Both can result in symptoms.  These typically include:

Pins and needles or numbness in your little and ring fingers, often worse at night.

Loss of grip strength and wasting of muscles in your hand

It may also cause pain in your inner arm and forearm

Diagnosis in Cubital Tunnel syndrome

The symptoms and clinical examination are often highly suggestive.  Nerve testing (neurophysiology) is useful to characterise the degree of compression and any other compressions in your arm.  

Treatment Options in Cubital Tunnel

If your symptoms are mild and your nerve function is good you may benefit from elbow splinting at night, or an injection.  If your symptoms are more intrusive, or they have failed to respond to the splint or injection, you may benefit from surgery.  If your nerve testing shows dysfunction it is generally recommended that you have surgery to prevent deterioration, as recovery once hand weakness has set in is unpredictable.

Cubital tunnel release

This is done as a day-case under general anaesthetic.  A 5-7 cm incision is made over the inside of your elbow.  Your ulna nerve is identified and fully released. Sometimes your nerve needs to be ‘transposed’ (moved infront of the knuckle of your elbow) if it is unstable, or in a revision surgery. Your wound is sutured with dissolvable stiches and you have a bulky dressing applied.

Recovery after Cubital Tunnel Release

You can take down your bulky bandages at 3 days but please leave the small plaster over your wound and keep it dry for two weeks. You can gently move your arm an hand immediately.

Most patients are safe to drive after a week. You can expect to return to desk work after a week, but heavy work may take a few weeks. 

Are there any complications?

This is a well tolerated and successful operation, but some patients do experience problems:

Infection – this is uncommon and normally settles with antibiotics.

Lack of benefit - This is uncommon.  If your ulna nerve has been badly compressed for a long-enough time that the muscle nerve endings in your hand have withered, then your weakness will not recover, but nor should it deteriorate once your nerve is released.  

Neuroma - There are small skin-nerve branches that cross the surgical site.  While every care is taken, these can sometimes be injured.  This may cause a very tender spot in your scar.  Very occasionally this does not improve with massage and time and revision surgery to bury the affected nerve is indicated

Complex regional pain syndrome (CRPS)  - a small proportion of patients develop pain, stiffness and swelling in response to injury or surgery to their arm or hand.  This rarely happens and is usually recognised early and treated by special painkillers and desensitisation physical therapy.  Occasionally it becomes severe and requires specialist pain doctor referral. 

 

3. Radial Tunnel Syndrome

This is the least common of the three conditions. The posterior interosseous nerve (PIN) supplies your posterior forearm muscles (these extend your wrist, thumb and fingers) and it also supplies sensory (pain) feedback from the wrist. Just beyond your elbow there is a tight band of muscle that can tether and entrap the PIN.  Symptoms can be quite vague but generally include:

Aching in the back of your forearm

Weakness and fatigue of grip

Pain over the outer aspect of your elbow

Sometimes mistaken for tennis elbow

Diagnosing Radial Tunnel Syndrome

Your symptoms and clinical examination are often suggestive

Nerve function testing may be helpful, but it is sometimes normal, despite convincing clinical signs and symptoms. A normal test does not therefore exclude the problem.

A diagnostic injection to numb the nerve may be useful to confirm the diagnosis.

Sometimes imaging such as Ultrasound scan or MRI can help identify a cause of nerve compression (e.g. a ganglion from the elbow joint or a fatty lump near the nerve)

Treatment Options in Radial Tunnel Syndrome

Initially it is worth trying rest, a wrist splint and anti-inflammatories. If these fail then an injection (cortisone) may help.  If both of these fail, or if the effect of the injection wears off, then surgery may be indicated.

Radial Tunnel Release

This is a day-case operation under general anaesthetic. An incision is made over the outer-front aspect of your elbow and down into your forearm to allow your nerve to be traced and released - from its origin to beyond any sites of compression. Your wound is closed with dissolving stitches and covered with a bulky dressing

Recovery after Radial tunnel release

You can take down your bulky bandages at 3 days, but please leave the small plaster over your wound for two weeks. You can gently move your arm an hand immediately. 

Most patients are safe to drive after a week. You can expect to return to desk work after a week or so, but heavy work will take a few weeks.  

Are there any complications?

This is a well tolerated successful operation, but some patients do experience problems:

Infection – this is uncommon and normally settles with antibiotics

Lack of benefit - this is uncommon, but sometimes other causes of pain in the region may co-exist (neck nerve entrapment).  If your nerve has been badly compressed for a long-enough time that the muscle nerve endings in your hand have withered, then your weakness will not recover, but nor should it deteriorate once your nerve is released.

Nerve injury - The posterior interosseous nerve is small and fragile. Every care is taken to protect your nerve, and injury to your nerve during surgery is rare.  If the nerve gets bruised, then it may turn off for a while, but it should recover. However a cut nerve does not normally recover on its own. If the nerve were to stop working permanently, then other surgery (tendon transfer or nerve exploration and grafting) might be required to restore your finger function

Complex regional pain syndrome (CRPS) - a small proportion of patients develop pain, stiffness and swelling   inresponse to injury or surgery to their arm or hand.  This is usually recognised early and treated by special painkillers and desensitisation physical therapy.  Occasionally it becomes severe and requires specialist pain doctor referral.