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