A method for sinus surgery includes piercing first and second access openings into the anatomy of a human subject to access an inaccessible sinus site for cooperatively manipulating respective first and second surgical instruments inserted through the openings. One instrument, for example an endoscope, can permit viewing of the sinus site while the other instrument is manipulated to effect a treatment at the sinus site. The maxillary and other sinuses can be accessed and anti-inflammatory and other treatments can be applied. Systems and instruments for performing such sinus surgery methods are also disclosed.