Also known as "J" deformity of IO.
Placement of the posterior fibers at, or anterior to, the inferior rectus insertion produces a “J” deformity, and will limit elevation of the eye. The complication of limited elevation has been termed by Mims et al as anti-elevation syndrome.
Stager has shown, through anatomical dissections, that the neurofi brovascular bundle of the inferior oblique inserts into the posterior fi bers and can act as a tether to hold the eye down. He found that the ligamentous structure of the neurofi brovascular bundle provides the ancillary origin for the posterior temporal fi bers of the inferior oblique muscle when its insertion is transposed anteriorly. Because of these concerns, the full anteriorization with a “J” deformity should be reserved for severe bilateral DVD with inferior oblique overaction. Mims stated that the author’s procedure of keeping the posterior fi bers posterior to the inferior rectus insertion prevents this complication.
Drawing shows the “J” deformity anteriorization and the neurofi brovascular bundle inserting into the posterior fi bers of the inferior oblique muscle. When the posterior muscle fi bers are moved anterior to the inferior rectus insertion the neurofi brovascular bundle tethers the eye, resulting in limited elevation.
- compiled & published by Dr Dhaval Patel MD AIIMS