A tissue protector has a body structure having a longitudinal extending thin web. The body structure has an unconstrained first shape configured to form a nerve shield and is configured to shrink about a longitudinal axis to a smaller constrained second shape sized to fit into a lumen of a cannula. Preferably, the second constrained shape is oval or round having a maximum diameter equal or less than an inside diameter of the lumen. The body structure is configured to return to the first shape when the cannula is withdrawn or returned to this shape as the implant advances.