I am highly appericeated for your very good efferts
I cannot give you any kind of formal opinion over the internet, and without seeing the scans myself, hence my advice is limited, and dependent on the written report
An area of 'bright T2 signal, consistent with myelomalacia' is consistent with the old injury you sustained previsouly and does not suggest any kind of 'new lesion'. Thinning of the cord is also a chronic process, from changes over time associated with the pre-fusion injury and after. I do not know if contrast was given as this may help differentiate an old with a new lesion, although old surgical areas can brighten with contrast for a long time after surgery.
The rest of th report does not suggest that there is an acute problem with the spinal cord, although there may be posture dependent tightening around the C4-5 level (ie the MRI is done lying flat only), and compression of the left C5 root might cause pain or numbnees in the left shoulder area or weakness lifting the left arm up.
I'm not sure what you mean by neuropathy ?sensory, and I am not clear how long your urinary symptoms are there (if there from the old injury, this would be consistent with the cervical injury, and may benefit from medication after defining the urinary problem with urodynamic studies), but if new, you should be re-evaluated as you are doing, but a lumbar MRI may be necessary to ruleout degenerative or displasced discs in this area also. There are some sensory tracts that could be involved slowly over time as cord thinning develops, that would supply the right as well as the left, depending on how much damage was done (the report does not mention the side of the myelomalacia ?both sides)
As with all patients with a sensory nerve problem you need to be careful with hot objects etc as you may not feel enough to avoid injury.
They should check your lower spine rather than your upper spine, i.e. neck. Myelomalacia simply means that you have lost tissue in the region of your old injury and there's nothing you can do about it now. However, your symptoms of "neuropathy" in legs and urinary frequency may signify a problem somewhere lower down. Don't rush to the neurosurgeon yet, find out where the problem truly lies.