According to the American Society of Regional Anesthesia and Pain Medicine, no while on plavix. Thienopyridine derivatives (clopidogrel and ticlopidine) should be discontinued at least 7 days prior to spinal procedures. See image below for their recommendations regarding other antiplatelet and anticoagulant agents.
Source
Horlocker TT, Benzon H, et al. "Regional anesthesia in the anticoagulated patient: defining the risks (the second ASRA Concensus Conference on Neuraxial Anesthesia and Anticoagulation)" Reg Anesth Pain Med 2003; 28: 172-97