Condition
Double Crush Syndrome
Double crush syndrome is a single nerve compressed in two places along its length at the same time, classically at the neck and again at the wrist.
- Seen at
- All three offices
- Typical wait
- Within the same week
- Treated with
- 3 procedures
In short
What double crush actually is.
Double Crush Syndrome
Double crush syndrome is a single nerve compressed in two places along its length at the same time, classically at the neck and again at the wrist. A nerve squeezed at one point tolerates less pressure everywhere else, so two mild compressions together can produce symptoms that neither would cause alone. This is one of the main reasons a carpal tunnel release sometimes leaves the hand still numb. Testing the whole path of the nerve, from the root in the neck out to the fingers, is what finds the second site.
Symptoms
How it shows up.
If several of these sound like your week, it is worth having the source looked at properly.
- Hand numbness that was operated on and either came back or never fully cleared
- Numbness involving more fingers than one trapped nerve should explain
- Neck or shoulder blade aching alongside the hand symptoms
- Tingling that starts in the neck and travels down the arm as a band into the hand
- A splint or a wrist injection that helped only partly, or helped only briefly
- Weakness in the hand that is out of step with how mild the wrist findings are
- Symptoms that flare with neck position as well as with wrist and hand use
What causes it
- Arthritis or a disc herniation narrowing the opening where a nerve root leaves the neck
- Carpal tunnel at the wrist or cubital tunnel at the elbow sitting on the same nerve path
- Diabetes, which leaves nerves more vulnerable to pressure at every point along their length
- Thyroid disease, long term alcohol use or chemotherapy, which create the same background vulnerability
- Repetitive work that loads the neck and the wrist together, such as assembly work or long hours at a keyboard
- Compression at the thoracic outlet acting as the upper site instead of the neck
When to act
Stop waiting when this happens.
Do not sit on these
Any one of the following is a reason to be seen rather than to wait it out.
- Carpal tunnel surgery did not fix the numbness, or the numbness returned within months
- You have neck symptoms and hand symptoms and nobody has connected the two
- The numbness does not fit the territory of any single nerve
- There is new weakness in the hand, or thinning of the muscle pad at the base of the thumb
- Arm weakness with neck pain plus any change in balance, walking or bladder control, which needs prompt evaluation for pressure on the spinal cord
Diagnosis
Finding the actual source.
A diagnosis is not a guess from an image. It comes from the exam, the history and, where nerves are involved, electrodiagnostic testing.
- Testing the entire nerve path in one session rather than the wrist alone, which is the only way a second site is found
- Nerve conduction studies across both the wrist and the elbow, with comparison segments above and below each possible compression point
- EMG of muscles supplied by specific cervical nerve roots, which shows whether the root in the neck is contributing and at which level
- A sensory map checked against the territories of the median, ulnar and radial nerves and of the C6, C7 and C8 roots, since the overlap is the clue
- Provocative testing at both ends: Phalen and Tinel signs at the wrist, and a Spurling test at the neck
- MRI of the cervical spine when the electrical testing implicates a root, ordered to confirm the level before any injection is planned
Nerve testing happens here, not elsewhere
EMG and nerve conduction studies are done in the office and read by Dr. Sheikh the same day, rather than sent out and waited on.
Treatment
How double crush is treated.
Ordered from the most common first step to the options reserved for pain that has not responded.
15–30 minEpidural Steroid InjectionAn epidural steroid injection puts anti-inflammatory medication into the epidural space, the area just outsid…Read more →
15–45 minNerve BlockA nerve block is an injection of local anesthetic, often with a steroid, placed next to a specific nerve or c…Read more →
Trigger Point InjectionA trigger point injection treats a knot in a muscle, a tight band that will not release and that often refers…Read more →Questions
Double Crush Syndrome, answered.
Why did my carpal tunnel surgery not fix my hand?
There are a few possibilities, and a second compression site is one of the most common. If a nerve root in the neck is also compressed, releasing the wrist removes only half the problem and the hand stays symptomatic. Testing the whole nerve path shows whether that is what happened, and it is worth doing before considering a second operation.
Is double crush syndrome a real diagnosis?
The concept is debated in the research literature, and reasonable specialists disagree about the mechanism. What is not in dispute is the clinical pattern: people with both a cervical root problem and a wrist or elbow entrapment tend to have worse symptoms and respond poorly when only one site is treated. The practical response is to test both.
Which site gets treated first?
Usually whichever one the testing shows is doing more of the damage, and whichever is easier to address without a procedure. Sometimes treating the more severe site is enough for the nerve to tolerate the milder one. If symptoms only partly resolve, the second site is already identified and can be addressed next.
Does diabetes make this more likely?
Yes. Diabetes makes nerves more susceptible to pressure everywhere along their length, which is why people with diabetes develop entrapments at several sites more often. It also means the underlying neuropathy has to be accounted for, or the nerve testing gets misread as two compressions when there is a third factor underneath.
Can one test cover both sites?
Yes. A properly performed study examines nerve conduction across the wrist and the elbow and includes EMG of muscles supplied by the cervical roots, all in one appointment. A study limited to the wrist answers only the wrist question, which is exactly how a second site gets missed.
Get a real diagnosis for double crush.
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