Optic Nerve Sheath Fenestration Using a Headlight Only

I believe that the medial lid crease approach is likely the preferred method for performing an optic nerve sheath fenestration.  The incision allows a direct approach to the optic nerve.  However, in patients that have relative enophthalmos, this approach can be difficult.  I always examine the axial position of the globe carefully in patients who will undergo optic nerve sheath fenestration.  If they have relatively enophthalmos, I prefer to perform a lateral approach. 

This is Richard Allen at oculosurg.com.  This video demonstrates an optic nerve sheath fenestration using a medial lid crease approach.  The eyelid crease has been marked.  A 15 blade is used to make an incision through the skin.  A traction suture is then placed through the upper eyelid margin at the level of the Meibomian gland orifices with a 4-0 silk suture.  A 7-0 Vicryl suture is placed partial thickness through the superior medial limbus so that the globe can be rotated inferior-laterally.  The needle tip cautery is then used to dissect through the orbicularis muscle to the underlying orbital septum.  The orbital septum is opened and the preaponeurotic fat is identified.  The medial edge of the preaponeurotic fat is exposed as well as the medial fat pad.  Dissection with be directed between the medial and preaponeurotic fat which will place the dissection plane medial to the medial edge of the levator muscle. Narrow malleable retractors are then used to dissect into the orbit toward the optic nerve.  I have seen experienced orbital surgeons get lost in the orbit (including myself).  The goal is to follow the posterior surface of the globe and keep the malleable retractors perpendicular to the path of the optic nerve.  The mistake that is made is that the malleable retractors will be directed posteriorly, which essentially places the malleable retractors parallel to the path of the optic nerve.  This results in more posterior dissection, but will not result in exposure of the optic nerve.  The optic nerve will be palpated with the malleables and strummed.  The 7-0 Vicryl suture acts to place the insertion of the optic nerve into the globe in a superior medial position.  Once the optic nerve is exposed, saline dampened ½ by 3-inch neurosurgical cottonoids are packed around the nerve.  This allows the fat to be held back by the cottonoids.  It is not uncommon to have to place more than one cottonoid medial and lateral to the nerve.  The malleables are placed over the cottonoids.  The loose tissue around the nerve sheath can be moved away from the sheath with cotton-tipped applicators or a freer periosteal elevator.  Myringotomy forceps are then used to grasp the sheath, and straight Yassargil neurosurgical scissors are used to make an incision anterior to the myringotomy forceps.  The straight scissors are used to make an incision laterally and medially.  It is useful to not release the myringotomy forceps from the optic nerve sheath.  Curved Yassargil scissors are then used to complete the formation of the window with an incision posteriorly.  I send the optic nerve sheath sample to the pathologist for evaluation for two reasons:  one is to ensure that the tissue is normal (i.e. no tumor or inflammation) and the other is to document that the surgery was successfully completed.  This procedure was performed with loupes and a headlight only.  It is very reasonable to use a neurosurgical microscope for the fenestration.  The fenestration is demonstrated.  There is no active bleeding.  The neurosurgical cottonoids are then removed.  The eyelid crease incision is then closed with interrupted 5-0 fast absorbing sutures.