I think an hour of muay thai is not as bad as IPPT, but you need to ask a doctor bro...

Whats the diagnosis by the doc?

Depending on intensity and frequency on these sensation, high impact sports may/may not be suitable.

Best to consult your doctor to seek opinion. Exercise need not necessary be high intensity or impact, consider exercises which strengthen your core(abdominals AND back) like pilates or basic core conditioning exercises will do just as fine.

Check out Youtube videos for key words like cow/cat back stretch, or a general core strengthening as keywords.

Daily stretching of the (upper and lower) back for about 3x20sec can also help to strengthen the muscles.

If you do ever start on a program, a good tip is to alert the instructor of your condition and determine if modification can be made to the routine.

Of course moves like throws,pushes or even groundwork are best to be left undone unless cleared by doctor.

Though usually its mind over body during exercise fatigue . There are times that we need to listen to our body as well.

spyglass,

I too have bad back (disc prolapse), and stopped MT for 2y already. If u have the same thing, I advice u to stop n get it heal, else it will keep coming back. This is what u need to do:
1) Consult docs, check for the common symptoms: numbness on the legs n butt, nerve pain at the back when sneeze, frequent spasm on the back (back tilted to one side).
2) If you have following symptoms, u will most likely to go for MRI. Is exp, hopefully cover by SAF. MRI enable u to locate which part of the spine giving u problem.
3) Cause of disc prolapse: bad sitting posture for long period of time or carry weights (espc squat, deadlift or barbell press) with bad posture. Of cos, weak core muscle.
4) Rehab: First u need to get the spasm away. Easiest way is to take anti inflammatory pills such as Arcoxia 90mg (NSAID). Once the pain subside or spasm gone, u shd start doing more core strengthening exercise or join pilates rehab program to learn the right posture. Is long n exp rehab.
5) If you wanna go back to MT, make sure yr back is better, and u developed the ease of core tightening. Basically core tightening is like u breath out when punch or kick, the breathing process will follow by tightening of core muscle. This will protect yr back from impacts.
6) But before u start MT training, I advice u to do boxing instead. As legs kicking n knee n clinching is quite tiring for the back. Once u comfortable with yr back, then go back to MT.

Dont rush it, as disc problem is long way to recover. I been down for 2y already, and still not fully recover. Everytime i go back MT, it will hurt me more n delay the recovery process.