A brace or support helps keep the palm flat....ish so helps stop the sides of the Carpal Tunnel inhibiting the nerve.
I have written and spoken before of the crease that appears on the palm when the thumb moves over to meet the fingers and the valley it forms. So what follows is a 'laymen's " idea in terms of what is going on in the hand as far a bass playing is concerned.
At the base of the thumb the pad moves laterally to support the movement as the thumb comes over to oppose the fingers and creates a crease in the palm, depending on how far over the thumb moves will determine the depth of the valley the crease turns in to.
When the crease is formed it brings the edges of the Carpal tunnel in, this is not an issue, the tunnel is designed to deform and re-form its shape to deal with the complex hand movements we have.
The Carpal Tunnel is access route, so muscles, nerve, blood vessels, etc share this 'highway' as they do though he wrist. The wrist is the bottle neck for many of these services as they all try and get past the complex system of bones and joints to service movement.
The issue is over time is the valley is formed and finger use is maintained during the time it is formed then there is a motion that is rubbing against the sides of the Carpal Tunnel, in a sense.... wearing it away a such. When the sides cannot de-form and re-form they cannot resist the action of the muscle running over the top that is part of the roof, so the roof in effect caves in, pulls the walls in and the nerve within the Carpal Tunnel is trapped, so we get the symptoms as a permanent feeling.
The extent of the collapse depends on the hand use and the physiology of the person, not everyone has the same hand use and not everyone has a perfect healthy hand.
Add to this the length of time and intensity of use and the problem becomes complicated to correctly say what has caused the symptoms when the appear, we can pinpoint where they are originating and the cause, by why the cause happened is in understanding the persons hand and how they have used it in their life.
Sometimes this is "the straw that broke the camels back" situation, in that damage occurred earlier in life and it only needed a more intense use in later life to expose it, as playing bass would do
So bass playing was not what caused it as such, the intense use of the hands, with the increase in use we would use in learning has exposed what was there.
If the person never played bass the injury may never have been exposed by it, if they took up tennis or golf and put in the time and effort to that, then that intense use may have exposed it, even an intense use on computers will expose a weakness.
But as far a bass playing is concerned it is that thumb position i talk about, the putting of the thumb up-right on the neck means it has to move laterally into this position, so the pad comes over and forms the crease, and the Carpal Tunnel area is now being deformed (deforming is not a bad thing it is just a term to describe the change of shape) and the valley in the palm is formed.
The action of using the fingers means that the muscles that also use the Carpal Tunnel are forming and deforming within the tunnel to make the fingers move.
What i say is do not move the thumb over, do not put it up-right on the neck in such a way that you form the crease and so form the valley.
If you have to move the thumb over, then make it a function to support use.....then let it move back to a neutral position.
So in effect you de-form and re-form the hand within the use of the motion of the fingers.
In holding that thumb up-right behind the fingers in the middle of the neck is keeping the Carpal Tunnel deformed throughout the finger use, so making it more susceptible to wear and tear, so weakening the sides of the Carpal Tunnel and making it easy to de-form and stay de-formed.
Part of the Bass Guitarist problems is they relate to Double Bass Pedagogy.
This is a flawed idea and only came into use because the instruments were seen as doing the same job back when the Electric Bass Guitar was introduced
But the reality is they have a completely different impact on the body and on the hands.
In all Double Bass Pedagogy that accumulated over the centuries, none that developed it and used it could ever imagine a Bass Guitar and the designs, sizes and ergonomics the design would offer, or the genres and techniques that would accompany it.
Double bass had one design and two techniques Pizzicato and Arco, although Arco had two schools of thought on use of a bow, overhand or underhand (French and German respectively).
We as bass guitarists have to look at what it is we do....we play guitar, not Double Bass, it may be a bass guitar but the focus for technique is on the guitar part not the bass part.
Playing bass Trombone is based on Trombone, playing bass Sax is based on Sax etc...none of them use Double Bass techniques as such.
So look at your own technique and decide is your hand use relevant to what you play and of you can use safer positions such as neutral thumb, straight wrists, thumb over the top etc...then use them all the do is relieve the un-needed stress and strain on the hand.
Because we have become accustomed to stress and strain does not mean it is not there, it just means we have learned not to notice it or associate any issues with it within a use.
I am not saying anyone has to change, or anyone is right or wrong in how they use their hands, all i am saying is there are reasons why problems occur and to be aware of how you use your technique. This applies to a lot of activities and the forums they have on the web have the same issues with CTS that we have with it.
Thanks to all for sharing their experiences, CTS is not the end of the world, neither is surgery, in fact for many, surgery it is a new start and asks the question " why did i suffer rather than do something sooner" and that is the object of this thread to let anyone with doubts realise you are not alone in this, talk to others and decide what is best for you.
If you have had surgery, good or bad then please share your experience, what sufferers need to see is a way forward and the fact that there is light at the end of the tunnel.
In my case (it was a broken neck) that caused all, and still does, my hand problems, i changed my bass, my amp, my strings my set up, my practice, my diet, my mattress, my pillows, my car and more..... to alleviate my problems.
I still after five and a half years manage my injuries, there are no time limits on anything i do, it will take as long as it takes.
Getting your mind and thought process sorted out is the big step, accepting there is a problem and being prepared to take it on.
Its not about regaining or maintaining what you once had, its about making the best of what you now have, and how to best move forward and play.