Sharing the technique of minimal invasive Sub-Tenon anesthesia for pars plana vitrectomy.


Case series, description of technique and instructional videos.


The standard Sub-Tenon cannula has a curved 19G shaft with a smooth flattened tip and can provide adequate anesthesia and akinesia of the globe, if the anesthetic is administered in the posterior Sub-Tenon space. This technique has proven to be safer than retrobulbar anesthesia using a sharp needle, while not compromising on the effectiveness. To insert the standard 19G Sub-Tenon canula, a conjunctival incision with Wescott scissors is used. This means that in our current small gauge vitrectomy the conjunctival trauma caused by the anesthesia procedure is usually larger than from the vitrectomy procedure itself.


An alternative to the 19G Sub-Tenon cannula is the tri-port 21G Sub-Tenon cannula (Eagle Labs, California, USA). This angled blunt cannula can be inserted directly through the conjunctiva and Tenon. This single step procedure is faster and less traumatic than the standard technique using Wescott scissors and a 19G cannula. While fixating the conjunctiva and Tenon with forceps, the tri-port cannula can be inserted following the globe posteriorly, reaching the retrobulbar space. With correct placement it provides a fast way of administering the anesthetic resulting in adequate anesthesia and akinesia. Because of the tri-port design, reaching the retrobulbar space using the right insertion technique is essential to overcome the risk of conjunctival swelling. The technique and it’s pitfalls will also be demonstrated using videos.


The 21G tri-port cannula offers a fast and useful minimal invasive technique to provide adequate Sub-Tenon anesthesia for eye surgery in general, and for small gauge vitrectomy in particular.



Radboud University Medical Centre
Email : jan.huelle@doctors.org.uk
Cell Phone: +491797524359
Work Phone: +491797524359