OPTIC NERVE FENESTRATION

INTRODUCTION

Optical nerve fenestration is a surgical process used to soothe elevated intracranial pressure. This method of surgery is usually used to treat papilledema due to idiopathic intracranial hypertension (IIH). Quick and/or accelerating loss of vision rather than the headaches is a common symptom of this condition. The effect is normally restricted to the ipsilateral optic nerve, however sometimes this method may have a filtration effect. This effect breeds through the entire system, which causes improvements in headaches and contralateral disc edema as well. In some cases, this procedure can also be used to stabilize or reverse the loss of vision due to optic nerve sheath hemorrhage, cryptococcal meningitis with papilledema, and intracranial breast cancer metastases with papilledema.

THE PROCEDURE

Optical nerve fenestration uses different techniques and procedures depending on the need. The most common technique is the transconjunctival medial orbitotomy approach. This method is performed under general anesthesia, after which, the eye and eyelid are prepped and draped in a standard ophthalmic surgical fashion. The detailed procedure involves placing of the eyelid speculum, peritomy at the nasal limbus and making incisions and dissection, insolation of rectus muscle, disinsertion of the muscle and running a stitch.

POST PROCEDURE CARE

Post procedure care involves the following:
      Avoidance of anticoagulants
      Systemic intake of antibiotics
      Intravenous steroids
      Regular eye check up
      Antibiotic-steroid drop for 1 week

COMPLICATIONS

Optic nerve fenestration surgery involves the following possible risks and complications:
      Diplopia, which is typically temporary
      Sudden loss of vision (either from a vascular occlusive event, direct injury to nerve, or a hemorrhage)
      Orbital or intrasheath hemorrhage resulting in vision loss
      Pupillary abnormality from damage to parasympathetic nerve fibers

FAQ ON OPTIC NERVE FENESTRATION AND IDIOPATHIC INTRACRANIAL HYPERTENSION

What is idiopathic intracranial hypertension?

Idiopathic intracranial hypertension (IIH) is a condition which is caused by an increase in the pressure of the Cerebro-Spinal Fluid (CSF). This fluid is present in our body to shield the brain and spinal cord. To maintain this fluid pressure, the CSF, which is constantly produced by the brain, is reabsorbed back into the bloodstream at a constant rate. An increase in the pressure of this fluid causes idiopathic intracranial hypertension (IIH).

What are the symptoms of idiopathic intracranial hypertension?

      Headaches that are associated with nausea
      Pulsating ringing, which is heard in both ears or one
      Loss of color vision
      Horizontal double vision
      Radicular pain in arms or legs
      Transient obscurations of vision
      Visual field defects

Can idiopathic intracranial hypertension affect children?

The answer is yes. Idiopathic intracranial hypertension can affect children. It affects both prepubescent children and post pubescent teenagers. IIH In prepubescent children is of the secondary type and affects males and females equally.

How is pediatric idiopathic intracranial hypertension diagnosed?

Usually, pediatric idiopathic intracranial hypertension is diagnosed by examining the optic nerve for swelling and the visual fields for defects. Sometimes, a procedure called lumbar puncture is carried out to estimate the pressure as well as the content of the CSF. High pressure of CSF indicates IIH.

How is idiopathic intracranial hypertension treated?

Treatment includes medications which help in lowering the CSF pressure, thus decreasing the optic nerve swelling. Medications used for this purpose include carbonic anhydrase inhibitors, steroids, migraine medication, and diuretics.
In some cases, surgical methods are used to treat this condition. Surgery of the spinal cord or optic nerve fenestration is used to treat this condition.

Are there treatments besides medicine and surgery that can help?

Besides surgery and medication, this condition can be improved by losing weight if they are obese. It is a good idea to visit your doctor and dietician to discuss about your weight loss goals.

What is the prognosis of idiopathic intracranial hypertension?

People with this condition experience progressively worsening vision and sometimes, may eventually become blind. There is a risk of recurrence even after the symptoms have been treated.