Patients with UC (Ulcerative Colitis) are, generally, referred for surgery when they are severely emaciated, steroid dependent, in poor general condition, and in need for an emergent operation with obvious sub-optimal result.
You point out a clear dilemma when treating chronic severe UC. Surgery remains a very good options for these patients, but recent progress with biological therapy has increased the options. In many countries there are financial restrictions on the use of anti-TNF drugs, however.
When anti-TNF are used, I would aim for achieving remission or at at least a very good response. Those patients with a partial response will likely require surgery soon and may benefit from elective rather than emergency surgery. We are however expecting the licensing of new drugs soon that will increase options further (Vedolizumab, Golimumab).
The best use of these drugs are early - before the patient is severely emaciated or even steroid dependent. Selective adhesion molecule blockers are attractive targets as they do not overall decrease systemic immunity and have demonstrated great remission rates without much side effects. Proportion-wise however, they may increase gastrointestinal infections.