Brief Answer:
Chances are good.

Detailed Answer:
I read your question carefully and I understand your concern.

The information you have read on the internet does have a point because many causes of tethered cord do require surgery to untether the cord. However as you yourself have seen those cases requiring surgery have many other signs as symptoms such as weakness of the lower limbs with gait difficulties, progressive severe pain, urinary disturbances and surgery is needed to help with those symptoms. You have to understand that the overwhelming majority of spina bifida patients have some tethering, but surgery is needed only in case of deterioration.

In your case as you yourself said you don't have such symptoms, have had a normal life conducting mild sporting activity as well. Because of that your doctors maintain that while there is a degree of tethering that is causing no major suffering of the nerves. Also because you are now 32 and usually the symptoms appear earlier they are right to be optimist and predict you won't have any deterioration of your symptoms. That is why they say you will be alright.

Even if you were the exception to the rule, who started to worsen at an older age still it won't be a deterioration happening overnight, it will be very gradual and there will be plenty of time to diagnose it and intervene surgically before there is any long lasting damage. So since you seem to be a well informed person who will know to ask for re-evaluation if new symptoms occur I am sure management will be in time.

So my opinion is that you have very good chances of leading a normal healthy life, most probably without needing any surgery, but even in the worst case surgery scenario you will be able to return to normal function afterwards.

I hope to have been of help.

---

Brief Answer:
Read below.

Detailed Answer:
As you yourself said it's hard at times when the symptoms are subtle to differentiate. When you say you feel it when you press, that makes me think there is at least some degree of psychological pressure because local pressure is not transmitted to the cord and shouldn't play any role. Since you speak only of some tingling and stretching feeling the symptoms don't look to me to be affect you as much as to warrant a surgery though.

If there was a motor deficit in your limbs I believe you would feel it in your daily activities. Also I suppose since you were seen by three neurologists they did conduct a neurological exam to formally evaluate your motor strength, muscular atrophy and pathological changes in your reflexes which would accompany muscle weakness due to tethered cord. So while I can't test those functions virtually, I am inclined to believe at least one in three neurologists would have spotted them.

An objective way to reinforce that opinion and evaluate whether there is real suffering of the nerves would be electrophysiological testing of your lower limbs (including evoked potentials, electromyography, nerve conduction studies and late responses). That would help in reassuring you and in case there abnormalities even if surgery wasn't needed, would serve as a comparison in case other repeat studies will be needed in the future.

Wishing you good health.

---

Brief Answer:
Read below.

Detailed Answer:
Plantar fasciitis can cause the pain in the heels and abnormal sensation, however since similar symptoms are caused by suffering of S1 nerve roots it is hard to assess given your history of cord tethering.

For that reason the nerve conduction studies I suggested earlier would be useful to differentiate whether the symptoms derive from nerve damage, or other causes like fasciitis, anxiety.

Whatever the result of those tests though, you should stop panicking. Even if your tethered cord was at the root of your symptoms you should keep thoughts about paralysis out of your head. As I said before in the worst case scenario worsening wouldn't happen overnight but over many months/year (32 years already passed), it would be very gradual and surgical procedure would relieve the pressure before any irreparable damage happened.

I hope my answer was able to ease your worries.

---

Brief Answer:
Read below.

Detailed Answer:
Well, now you are making me feel bad about my calming abilities because at every my attempt you seem to respond with more anguish, maybe I should quit (just kidding).
First of all I said that most probably you will not need surgery so since I'm the fourth doctor saying so why do you have to think about it. By the way surgery wouldn't involve the cord itself, the tethering is at the cauda equina level at L4-L5, it's below the cord itself (the cord ends at L3 level) so it would be only the peripheral nerves which would have to be freed. So you can stop visualizing that image of the scary white spinal cord. It's one of the safest procedures, but as I said you probably won't need it.
As for alternatives to solve a tethering, no unfortunately there are no such alternatives. What you mentioned, such as medicines, physical therapy can provide relief from pain symptoms but can not solve the actual tethering.

I remain at your disposal for further questions.

---