The document summarizes research on the effectiveness of optic nerve sheath fenestration (ONSF) for treating idiopathic intracranial hypertension. Case series show that ONSF is effective in the short term for resolving papilloedema and preventing visual deterioration in 85-94% of patients, though not as effective for headaches. While unilateral ONSF may be sufficient, long-term recurrence is common. ONSF appears similarly effective as lumbar punctures or ventriculoperitoneal shunts, though randomized controlled trials are still needed to determine best treatment.

1. EBS Presentation
Effectiveness of optic nerve sheath
fenestration in idiopathic intracranial
hypertension
Johnny Wong
14th July, 2011
Advanced Scholar: Prof Marcus Stoodley

2. Introduction
• “Benign intracranial hypertension”
• “Idiopathic intracranial hypertension”
• “Pseudotumour cerebri”
• Symptoms: Headaches and visual blurring
• Treatment options
– Conservative: Weight loss, diet, diuretics, acetazolamide, corticosteroids,
octreotide
– Surgical procedures: Optic nerve sheath fenestration, CSF diversion –
multiple lumbar punctures, LP or VP shunt, subtemporal decompressions
– Venous stenting

3. Clinical Questions:
• Primary Question:
What is the effectiveness of optic nerve sheath fenestration
(ONSF) in patients with idiopathic intracranial hypertension?
• Secondary Question:
How does ONSF compare with other treatments for
idiopathic intracranial hypertension?

4. Search strategy
• P = Idiopathic intracranial hypertension
• I = Optic nerve fenestration
• [C = Other surgical procedures (eg CSF shunting;
sinus stenting) ]
• O = Treatment outcomes
• Cochrane, Ovid Medline, Scopus, Google Scholar
• MeSH terms: “Pseudotumour cerebri” ; “ophthalmologic surgical
procedures”

5. Cochrane
• Methods:
– Searched for RCT only
– 3 categories: Idiopathic patients
with papilloedema; Idiopathic
without papilloedema; IIH with
underlying aetiology
– 7 Interventions types
• Results:
– 85 studies relevant to IIH
– 1 RCT found – poor
randomisation (acetazolamide)
• Recommendations:
– Optic nerve fenestration or LP
shunt for papilloedema
– Further research required

6. Ovid Medline
5 useful articles identified

7. Ovid Medline
12 useful articles identified

8. Scopus
10 additional
useful articles

9. Primary Question – Efficacy of ONSF
• No RCT; Case series only;
• 3 review articles found
• Prevent visual deterioration; Improved VA,
not HA (33-50% not relieved)
• Review by Brazis et al(2008), Uretzky et al.
(2009)
– Papilloedema: 86-97% resolved or sig. improved
– VA: 85-91% Improved or stabilised
– VF: 48-95% improved; 25-38% stabilised

10. Primary Question – Efficacy of ONSF
– Bilateral VA improvement from unilateral ONSF
– Better for acute papilloedema
– 10-15% worsening vision
– 4.5-45% complication rates
– Long-term (5 years):
• 36% improvement
• 32% stabilisation
• 33% later deterioration after initial improvement
– Maintenance of vision
• 66% @ 12 months; 55% @ 3y, 38% @ 5y, 16% @ 6y

11. • Retrospective series of 32 patients, 51 eyes
• 41% with PTC; 47% ONSF as primary procedure
• 11/17 had second shunt procedure

12. Case series
• Retrospective case series; 10 patients with
bilateral ONSF
• All 10 patients improved in papilloedema and
VA in short-term
• Long-term: evaluation difficult due to
concomittant treatment

13. Case series: Alsuhaibani et al, 2011
Effect of Optic Nerve Sheath Fenestration on
Papilloedema of the operated and
contralateral non-operated eyes in idiopathic
intracranial hypertension
• Retrospective series; 62 patients unilateral ONSF
• Pre-op papilloedema scores: Ipsi & contral – 3 & 2
• Post-op: 2 & 2 (2 wks); 1 & 1 (3 & 6 months); 0.5 & 1
(12 months)

14. Secondary question: Comparison with
other treatments
• No RCT comparing surgical options or
medical treatment
• Case series and review articles
• LPS – effective in treating symptoms, but high
rates of revisions
• VPS – difficult ventriculostomy with small
ventricles

15. LPS (Review articles – Brazis 2008)
(Burgett 1997: 30 patients)
– VA: 71% improvement of 2 lines; VF: stabilised in
62%; Symptom resolution: 82%
– Mean no. of revisions: 4.2;
– Revision rate: 55-63%
(Eggenberger 1996: 27 patients)
– 100% improvement
– 56% revisions (3 requiring 35 revisions)

16. LPS
• 40 patients; VAD in 21 patients
• 10 revision operations
• 7 intractable headaches

17. VPS (Review article – Brazis 2008)
Bynke 2004: 17 patients
– Symptom resolution: 100%
– Mean FU: 6.5 years
– Revision rate: 7/17 for 1 or 2 revisions
Woodworth 2005: 21 patients
– 100% initial improvement
– Failure rates: 10% at 1 month, 20% at 2 months,
50% at 12 months, 60% at 24 months
– Revisions for distal obstruction (67%) &
overdrainage

18. VPS
• 8/9 improvement in HA; 12 revisions in 6 patients

19. LPS vs VPS
• 115 shunt operations in 42 patients (79 LPS, 36 VPS)
• 95% improvement in headaches
• 19% and 48% recurrent HA despite functioning shunt
at 12 and 36 months respectively
• 2.5 fold increased risk of revisions with LPS
• 3 fold increased risk of distal obstruction with LPS.

20. LPS vs VPS
• Retrospective; 25 patients
• 72% LPS – 11% failure rate, 60% revision
• 28% VPS – 14% failure rate, 30% revision

21. Conclusion
• ONSF effective in short term for papilloedema
and visual deterioration (85-94%); not HA.
• Unilateral may be adequate;
• Long-term recurrence
• Efficacy similar to LP or VP shunts
• RCTs required for best treatment for IIH