It is nothing to be concerned about as it is normal to have a little twitching after surgery for a herniated disc.

It is due to the weakening of the muscle of the calf which occurs due to operation and also due to the nerve injury because of herniated disc. It is medically called a clonus and represents the muscles way of expressing weakness and atrophy of the muscle.

It can also happen if you have worn tight shoes due to crumpling of toes together.

I would suggest you to

1) To maintain a strict regimen of exercise to improve your general physical strength. Put more effort to improve the tone of your calf muscle with a dedicated cardio.

2) Get an MRI spine done to make sure the hernia has been treated satisfactorily.

3) Use comfortable foot wear, so as to not strain your foot and increase the chances of clonus. Preferably use open toes shoes so as to not cramp the foot and impede the nerve supply.

4) Physiotherapy is a good option to improve the tone of your muscle and prevent the recurrence of the clonus.

5) If the twitching persists consider electromyography to check for nerve conductance.

Thank you.