The insurance adjuster in my D.C. workers comp case sent me to an IME doctor who said I should have surgery but I'm not sure if I should. And now she won't pay my benefits until I have surgery. Can she do this?

No.

They cannot force you to have an invasive surgical procedure.  You obviously have a big decision when surgery is recommended but that recommendation should come from your treating doctor - a doctor who has examined and treated you over weeks, months or even years and has tried different therapies, injections, etc. before recommending surgery or has explained that the treatment for your injury is surgery - that therapy, injections, etc. won't help.

In D.C. you have the right to control your own medical care and treatment when you get hurt on the job.  Everyone with an on the job injury and a workers compensation case in the District of Columbia has the right to choose his or her own treating doctor.

Don't get bullied or lied to or tricked by the workers comp adjuster.  She may send you an official letter with a list of doctors to choose from, or tell you they only pay for treatment by doctors in their network or on their panel, or that they have pre certified doctors willing to take workers comp insurance so you have to go to one of those.

None of it is true.  Don't make the mistake of going to some insurance doctor who is looking out for the insurance company sending him business (you) instead of the patient's best interest.

And just this past Friday I heard another horror story about a "workers clinic" - that's a clinic that construction companies, insurance companies and employers send their people to when they get hurt on the job.  The physician assistant did not refer the injured worker to a specialist in time and the delay may make the injury much worse.

You should never settle for a "clinic" run by these people.   Their job is to minimize the amount of medical treatment and time out of work the workers comp insurance company has to pay for.