i'm more of the opinion that it looks like MBD (metabolic bone disease) which causes kinks in the spinal column of phelsuma's. It is not common, but it does happen. When she is sitting head downwards on a wall or such, does her tail flop over her head?
Also, yes, taht is far too small to be dropping eggs, in my opinion. perhaps they could not pass properly and broke the spine on the way out. This is unlikely however. Does she still have full control over such things as tail, toes, and hind legs?
I agree, it really is hard to tell wihtout an x-ray.
best of luck.
Mark