Why applying a Geometrical method to an orbital block may provide a safer yet effective approach to orbital blocks
I have used a variety of orbital block techniques over the years, both Intraconal and Extraconal. I was originally taught the Atkinson technique, the most common technique used for intraconal retrobulbar blocks, which directs the needle tip towards the orbital apex.
Reviewing the literature I came across an article by Gills-Lloyd (1983), which described their intraconal technique, directing the needle tip lateral to the Lateral Limbus. I began utilizing this approach in late 1985. The needle-tip is directed into the Intraconal Space lateral to the macula, optic nerve and larger orbital vessels.
To facilitate a more reproducible approach to teaching practitioners this Intraconal orbital block, I created a geometrical overlay to the technique in 2006, and my poster presentation, “A Geometrical Method Applied to an Orbital Block ”was accepted for the Ophthalmic Anesthesia Societies Annual meeting in 2008.
The geometrical approach utilizes an external measurement of the Orbital-Globe relationship, including the axial length if available, to calculate the distance from the needle insertion site to the equatorial plane of the globe. Once the needle-tip passes the equator of the globe the needle-tip can be redirected into the intraconal space, allowing for the most effective distribution and rapid onset of the local anesthesia to the cranial nerves.
This technique beautifully marries the concept of the extraconal peribulbar needle insertion until the needle tip passes the equator of the globe through a mathematical calculation of the individual’s orbital-globe relationship. After the needle-tip passes the equator of the globe, the needle-tip may be redirected into the intraconal space, the most effective area for the orbital distribution of the local anesthetic.
Start Today! Remember the importance of repetition to assist you in getting more acquainted and comfortable with the various orbital blocks. Our program allows you to watch the lecture as many times as you need to master the information provided.