Most of the options can be availed with strong will.
1. Weight reduction through dietitians,physiotherapist.
2.epidural blocks as your doc seems necessary at this point
3.After significant weight reduction over a year or so,surgical intervention like laminectomy
/ fusion of
spine may be advisable.These days in some centers, minimal invasive spine surgery is carried out, i wonder your current doc.might think of that possibility even at this stage or else you seek second opinion
with spine surgeons in your area/district/country.
Of-course your obesity is a problem now but it can be contained to some extent. Your disc problem can be resolved in due course also , so there should be no despair or hopelessness