I wouldn't be too harsh on those who made the original diagnosis 20 years ago.
I'll go into more detail, than you will need, but I will do so, so that others will understand.
Carpal tunnel syndrome CTS has symptoms of numbness, or tingly sensations, and later of weakness (when advanced) of the first three fingers of the affected hand, including the thumb. It is suspected, but never quite proven that it is caused by repetitive hand motion such as doing a lot of keyboarding.
The median nerve carries both motor and sensory fibers. It passes through the carpal tunnel in the wrist.
between the little bones of the wrist and the transverse carpal ligament. If that ligament thickens, it can put pressure on the median nerve, and cause the symptoms of CTS. Numbness, tingly, loss of grip strength, pain. This is similar to when one strikes his funny bone, except he is catching the Ulnar nerve.
The clinical diagnosis of CTS, is pretty simple. If the patient has the classical symptoms, and the examiner can elicit those symptoms by stretching the median nerve: have the patient rotate the head away from the affected side, and lean his head away from the affected side, then straighten the arm out to the side, hyper extend the wrist, and then tap on the median nerve on the inside of the wrist (as seen in the above picture). If the patient states that he gets the same tingly sensation, and or more intense, then clinically the patient has CTS.
A more advanced tool for the diagnosis is to do electrodiagnostic nerve testing. Electromyelograph / Nerve conduction Velocity tests are typically done together. The EMG tells how well the nerve and muscle are working together, and if the muscle is somewhat disconnected from the nerve.
The NCV tests the speed at which the nerve will carry an impulse, and to a certain extent, how many nerve fibers are firing. If there is pressure on a nerve, the speed of the impulse will slow at that point, and if severe enough not all of the impulses will get past the pressure point, and the tester will see a drop off in the number of fibers firing. The NCV is a terrific advanced tool for locating peripheral nerve entrapments.
The surgical solution is to cut that Transverse Carpal ligament to release the pressure on the nerve. Most people do pretty well with that. Especially if they have the correct diagnosis.
The median nerve can also get trapped in the forearm as it passes under the pronator teres muscle. IIRC studies have shown 30% of those with CTS also have entrapment under the pronator teres. If you have entrapment at more than one place, it is called a "Double Crush" syndrome. One can make a clinical diagnosis of entrapment of the median nerve under the pronator teres but with an NCV it would be definitive.
The median nerve is made of nerve fibers from three levels in the neck but most of them come from between the neck bones numbered C6-C7. With a bad disc, one can have pressure put on it all the way up in the neck and one can get shooting pains all the way to the hand, or the symptoms of CTS. Entrapment in the neck due to a bad disc would be seen on a MRI, and be evidenced with a EMG study. Not so much with an NCV.
Since the sensory fibers are more sensitive to pressure than the motor fibers, a patient may experience sensory deficits, or tingly sensations sooner than when the equipment will be able to pick up the neural deficits. Also, the NCV may pick up slowing of the impulse due to pressure, but there may not yet be conduction BLOCK, and the muscle may still behave normally when studied by the EMG.
Whew... with all that said:
@turbodog
It's possible that you have a double crush, one in the cervical spine, and one in the wrist and or forearm. IF CTS was confirmed with a NCV, and fusion of the C6-7 relieved you of your symptoms, then IMO you most likely have, or had a double crush.
You quite possibly still have a subclinical CTS.
Good luck my friend, I hope that your symptoms do not return.
Poppy
