Lecture - Carpal Tunnel Syndrome Flashcards
What is carpal tunnel syndrome?
Compression of the median nerve in the carpal tunnel
Median nerve anatomy:
- What does the median nerve pass under?
- What sensations does it produce?
- What muscles does it innervate?
- Either called flexor retaniculum or transverse carpal ligament). It passes under this and then divides into the digits
- – Radial side of the hand to the middle of the ring finger
– Palmar cutaneous branch - skin of thenar eminence - – Thenar muscles - abductor pollicis brevis (always)
- flexor pollicis brevis (usually)
- opponens pollicis (usually)
(Abduct muscle when point thumb straight up (palm facing up in the position))
– Radial two lumbricals
What’s the anatomy of the carpal tunnel look like?
The flexor surface is deeply concave and this arch is maintained by the flexor reteinaculum
What’re the three things in the carpal tunnel?
- Tendons: 9 of them (2 for each finger and one for thumb)
- Tendon sheaths: Tendons run in sheaths (slippery tissue to allow tendon to glide)
- Median nerve
Aetiology of carpal tunnel syndrome (stuff that causes pressure on median nerve):
- Swelling of the contents of the tunnel can be caused by what 6 things?
- Encroachment on the tunnel by what two things?
- Two other causes of carpal tunnel syndrome?
- TENOSYNOVITIS (Name given to inflammaiton to synovial tissue that provides the slippery layer around tendons. We also have synovial tissue lining our joints and they produce fluid. Synovitis is excess fluid. )
- RHEUMATOID ARTHRITIS (Causes inflammation of synovial tissue. Destrucution in joints and also can have carpal tunnel problems)
- HYPOTHYROIDISM (causes tissues to get thickened)
- DIABETES
- PREGNANCY (Carpal tunnel syndrome common in preg bc tissues become more waterlogged so less room for nerve in tunnel)
- ACROMEGALY (Growth hormone excess - tissue becomes thicker and all but cant get taller since growth plates shut down) - COLLES FRACTURE (Swelling from fracture can cause pressure) and DISLOCATED LUNATE (Dislocate lunate - it’s the floor of carpal tunnel so will get symptoms to nerve)
- Occupational (You can get swelling around tendons when you squeeze things) and idiopathic (just don’t know)
Symptoms:
What sensory symptoms? (4)
-Nerve usually supplies sensation (esp medial nerve) and stimulus to make muscles work so you’ll get sensory symptoms and all
- TINGLING / PAIN
- gripping eg. tools, steering wheel
- knitting
- WEAKNESS
- difficulty gripping
- dropping cups, teapot etc (If no sensation in hand then dont know how hard you’re holding something so people can drop things)
- CLUMSINESS
- STIFFNESS / LOSS OF USE OF FINGERS
Signs:
- What to look for
- Feel for
- Movement
- – Drier skin
– Wasting thenar eminence - Look for sweating and sensation: SNS - when you get fright, you get cold and clammy on extremities. Causes sweating, and shuts down blood flow. It also makes hair stand on end. If have compression of nerve - peripheral nerve like median nerve - which supply SNS fibres to hand. If nerve isn’t working, SNS wont work either. So you get opposite to cold and clammy - GET WARM AND DRY. Dry skin often looks different than normal skin. Feels FUZZY like glove on hand or something - you normally feel something but it aint normal
- Decreased power thumb abduction
Provocative tests - three of them
- Direct pressure over carpal tunnel - almost 100%
- If tingling in fingers then hv it - Phalen’s test - 88% sensitivity
- upside down hand prayer - Tinels test - 67% sensitivity
- Tap the nerve and test sensitivity of nerve
Electrodiagnostic tests - what are they and what for?
Electrodiagnostic tests:
For confirmation rather than diagnosis
– Nerve conduction (If signal slows down as it goes down as it goes down tunnel then something wrong)
– EMG (Electromyography - stick needle in thenar muscle and see if it responds in normal way )
Also tell us the severity of it
Can’t get full recovery after surgery but if mild symptoms before then can have full
Use tests to tell them what to expect after surgery
Can diagnose by asking them but might need clinical evidence to document it and then do something about it
-We tend to do these electrical tests
Treatment - 5 of them
- Rest / avoidance of activities
- “Don’t do it” - Splint in slight wrist extension
- Splint to hold splin straight at night bc curl hands when they sleep - NSAID’s
- Good for any inflammatory condition eg if you have inflam around tendons - Steroid injection
- To provide anti-inflam effect
But if bad pressure on nerve, person wont know bc you cover their symptoms (pain). Only give these when short-lived like pregnancy - it comes to an end.
- Surgical release (If you leave it, it can happen again and wirse as the pressure builds up so surgival release is done)
– Endoscopic (Can’t see if dont properly so do open mostly )
– Open
Open surgical release: Give adrenalin - consist BV so can see what doing
Put local anaesthetic (and go deep into the carpal tunnel and make sure it doesnt go to nerve)
Put incision over carpal tunnel - cut through the carpal transverse ligament in the middle and the pressure comes off. The two flaps will get back together somehow but less tight.
Make incision to ulnar side bc medial nerve on radial side
If dont release completely then will hv recurrent symptoms
Put a little metal thing under transverse ligamemnt and then xut ligament so you dont cut anything else
Under ligament, you have carpal tunnel
Even if wound on skin looks like its healed, the tissue underneath wont be healed.
What are five complications of open surgical release?
- Permanent weakness / numbness
- Reflex sympathetic dystrophy
- Weakness of grip post surgery
- Accidental division palmar cutaneous
or recurrent motor branch - Painful scar
