Patent ID: 9243881
Filing Date: 2016-01-26
CPC Classification: A61B,G01B

Claim Text:
1. A device for measuring a thickness of target material, the device being configured for use in conjunction with a retrograde drill including a tubular shaft, a drill bit disposed at a distal end of the tubular shaft, and at least one cutting member moveably disposed adjacent the distal end of the tubular shaft, the device comprising: a substantially transparent measurement tube having a proximal end and a distal end, the measurement tube being configured to receive and be slidingly engaged over the tubular shaft of the retrograde drill, wherein the cutting member of the retrograde drill is operative to move between a first position where a central axis thereof is coincident with a longitudinal axis of the tubular shaft of the retrograde drill, and a second position where the central axis thereof is disposed at a non-zero angle relative to the longitudinal axis of the tubular shaft of the retrograde drill, wherein the tubular shaft of the retrograde drill has a plurality of linear graduation marks on a surface thereof for identifying a plurality of linear measures, respectively, at least some of the plurality of linear graduation marks being observable through the substantially transparent measurement tube, and wherein each of the plurality of linear graduation marks aligned with the proximal end of the measurement tube provides a respective linear measure of a distance between the distal end of the measurement tube and the cutting member of the retrograde drill disposed in the second position, the respective linear measure corresponding to the thickness of the target material remaining while drilling or after having drilled a tunnel or bore through the target material using the retrograde drill.