Sub-Tenon's anesthetic administration for cataract surgery: how much stays in?

UNLABELLED

We performed a prospective, randomized trial assessing the "remaining" volume of anesthetic solution that stays within the sub-Tenon's space after administration of 2 different volumes: 3 mL and 5 mL. The remaining volume correlated with motor block (r = 0.72; P < 0.001). The volume lost through the incision as a percentage of total volume injected was similar in both groups, suggesting sub-Tenon's space is not limited to a finite injected volume less than 5 mL and may be capable of receiving larger volumes of anesthetic to improve motor block.

IMPLICATIONS

The volume of anesthetic solution remaining within sub-Tenon's space correlates with motor block. The amount of volume lost as a percentage of total administered is independent of the volume injected, suggesting sub-Tenon's space is not limited to a finite injected volume less than 5 mL and may be capable of receiving larger volumes of anesthetic to improve motor block.