Trigger finger release and lymphoedema

Please can anyone help me?
Last May 2007, I had a mastectomy and immediate reconstruction. I had eleven lymph nodes removed. I have only a tiny amount of lymphoedema in my hand and reconstructed breast.
However, I have developed a trigger finger which is disabling me. I need surgery to have the tendon released.
Part of the procedure is to apply a tourniquet to the arm for about ten minutes or so, to stop the blood flow during the surgery.
I have always been told not to have a blood pressure cuff or injection etc to the arm. So how will this pressure effect it?
I would be very grateful for any advice.
Thank you
Pattyann.