The lamina push test: an alternative to the globe push test for identifying the medial orbit during endoscopic sinus surgery.

Abstract

Aside from endoscopic and image guidance confirmation, the standard method of identifying the lamina involves the surgeon or an assistant applying gentle pressure on the globe externally. This globe push test requires the surgeon to remove one instrument from the endoscopic field or an assistant to press on the globe, and the test is most useful when either the periorbita or periorbital fat is exposed. We propose an alternative, equally accurate, and more efficient technique dubbed the lamina push test. A blunt instrument is used to gently apply lateral pressure in the expected location of the medial orbital wall. If the lamina has been adequately skeletonized, the entire lamina will be seen to move as a unit. If residual ethmoid partitions are present, no movement or only localized movement is observed. Using the lamina push test, we have been able to safely identify the lamina papyracea in all patients undergoing endoscopic sinus surgery, without injury to the lamina or orbital contents. The use of direct pressure significantly increases the movement of an intact lamina. The lamina push test is a safe and effective technique for identification of the medial orbital wall, confirmation of removal of all lateral ethmoid partitions, and verification of lamina integrity. It enables more consistent identification of an intact lamina, allows the surgeon to keep both instruments in the endonasal surgical field, and does not require an assistant.