A modified, sub-Tenon’s cannula for delivery of sub-Tenon’s local anesthetic solution, was manufactured from a standard disposable a 24G needle.
- It has a straight portion and a curved portion.
- The straight portion is 5 mm long and the curved portion is 27 mm long.
- The straight portion is tangential to the curved portion.
The advantages of the modification are:
- The straight portion of the cannula is tangentially angled to the curved portion. The junction of the two portions will help the surgeon to know when to stop the entry of the cannula into the sub-Tenon’s space and where the tip of the cannula will be.
- The curved portion is designed to be congruous with the curvature of the eyeball so that this portion will always remain in the sub-Tenon’s space and will precisely deliver the anesthetic solution in the sub-Tenon’s space.
- The length of the curved portion is 27 mm long so that it will be about 5 mm away from the optic nerve, and will not damage the optic nerve.
- By virtue of it curvature, it will penetrate the sub-Tenon’s space very smoothly.