Surgical Idiopathic Intracranial Hypertension Treatment Trial

Inclusion Criteria:

- Subject Eligibility Criteria Inclusion Criteria

1. Diagnosis of IIH by modified Dandy criteria (Table 4)

2. Age 18 to <64 years at time of consent

3. Age 18 to <61 years at time of diagnosis (time of diagnosis is the time at which the patient meets the modified Dandy criteria, usually after the lumbar puncture results are reviewed)

4. Presence of bilateral papilledema

5. Lumbar puncture within 6 weeks of screening visit or completed as part of screening: Opening CSF pressure >250 mmH2O or 200 to 250 mmH2O with at least one of the following:

- Pulse synchronous tinnitus

- Cranial nerve VI palsy

- Echography for disc drusen negative and no other disc anomalies mimicking disc edema present

- Magnetic Resonance Venography (MRV) with lateral sinus collapse/stenosis, partially empty sella turcica on coronal or sagittal views of MRI, and optic nerve sheaths with filled out CSF spaces next to the globe on T2 weighted axial MRI scans If the patient was treated with intracranial pressure lowering agents (e.g., acetazolamide) prior to obtaining a lumbar puncture, the agent(s) must be discontinued for at least 24 hours prior to performing the diagnostic lumbar puncture.

6. At least one eye meeting all eligible eye inclusion criteria and no exclusion criteria.

7. Able to provide informed consent

8. Investigator believes participant is a good candidate for the study, including the probability of returning for follow-up.

- Eye-Level Eligibility Criteria Subjects must have at least one eye meeting all of the inclusion criteria and none of the exclusion criteria.

If both eyes meet eligibility criteria at the baseline examination, both will be included in the primary outcome analysis.

Inclusion

1. Visual field loss meeting the following criteria based on two full threshold 24-2 size V tests reviewed by the VFRC:

- PMD from -6 decibel (dB) to -27 dB

- Reproducible visual loss present on automated perimetry including no more than 15% false positive response

2. Visual acuity better than 20/200 (39 or more letters correct)

Exclusion Criteria:

- Subject Exclusion Criteria Exclusion Criteria

1. Treatment of IIH within the past 3 months with either (1) the maximally tolerated dosage of acetazolamide for at least one week or (2) more than one month of acetazolamide with a cumulative dosage of more than 45 grams 'Maximally-tolerated dose' is defined as dosage was reached where dosage could not be increased further either because of side effects or because a daily total dosage of 4 grams per day was reached.

If individual discontinued acetazolamide in the past due to side effects, individual is only eligible if investigator believes that the individual is likely to tolerate acetazolamide, as it will be prescribed in the study.

2. Treatment of IIH within the past 3 months with either (1) the maximally tolerated dosage of methazolamide for at least one week or (2) more than one month of methazolamide with a cumulative dosage of more than 4.5 grams 'Maximally-tolerated dose' is defined as dosage was reached where dosage could not be increased further either because of side effects or because a daily total dosage of 400 mg per day was reached.

3. Treatment with topiramate within two months and average cumulative dosage for the preceding month of more than 700 mg per week

4. Previous surgery for IIH, including ONSF, CSF shunting, subtemporal decompression, or venous sinus stenting; gastric surgery for obesity is allowed

5. Abnormalities on neurologic examination except for papilledema and its related visual loss or cranial nerve VI to VII paresis; if other abnormalities are present, the patient will need to be discussed with the Study Director (SD) for study entry.

6. Abnormal CT or MRI scan (intracranial mass, hydrocephalus, dural sinus thrombus, or arteriovenous malformation) other than findings known to occur with increased intracranial pressure. Abnormalities on MRI that are not known to cause increased intracranial pressure are acceptable.

7. Abnormal CSF contents: increased cells: > 8 cells; elevated protein: > 45 mg%; low glucose: < 30 mg% (If the lumbar puncture produces a cell count compatible with a traumatic needle insertion, the patient does not need to be excluded if the CSF white blood cell count (WBC) after correction is 8 cells/mm3 or less - see Manual of Procedures (MOP) for calculation. If > 8 cells or > 45mg% in CSF protein are documented in the CSF or calculated after conversion from a traumatic lumbar puncture, the patient can be discussed with the Study Director for possible inclusion.)

8. Abnormal blood work-up indicating a medical or systemic condition associated with raised intracranial pressure

9. Diabetes mellitus with diabetic retinopathy

10. Ingestion of a drug or substance, or presence of a disorder, that has been associated with increased intracranial pressure within 2 months of diagnosis, such as lithium, vitamin A related products (e.g., Retin-A), or various cyclines (see MOP for conditions and drugs)

11. Laboratory test results showing severe anemia, leukopenia or thrombocytopenia, renal failure, or hepatic disease, based on the Site Investigator's judgment

12. Other condition requiring continued use of oral, I.V. or injectable steroids (nasal, inhaled, or topical steroids are allowed since the systemic effects are small). Patients with a condition that resulted in recent or current use of steroids but may be safely tapered off will be handled on a case-by-case basis after discussion with Study Director/co-Director. See Manual of Procedures (MOP) for details.

13. Presence of a medical condition that would contraindicate use of acetazolamide or furosemide or significantly increase surgical risk

14. Pregnancy or unwillingness for a subject of childbearing potential to use contraception during the first 6 months of the study Women of childbearing potential must use an acceptable form of birth control during the first 6 months of the study. Acceptable forms include oral contraceptives, transdermal contraceptives, diaphragm, intrauterine devices (IUDs), condoms with spermicide, documented surgical sterilization of either the subject or their partner, or abstinence.

15. Presence of a physical, mental, or social condition likely to affect follow-up (drug addiction, terminal illness, no telephone, homeless)

16. Anticipation of a move from the site area within six months and unwillingness to return for follow-up at a SIGHT study site

17. Allergy to pupil dilating drops or narrow angles precluding safe dilation

18. Presence of a condition that contraindicates general anesthesia

19. Participation in an investigational trial within 30 days of enrollment that involved treatment with any systemic drug therapy or therapy that affects the eligible eye(s)

- Eye Level Exclusion Criteria Exclusion

1. Intraocular pressure currently >28 mm Hg or >30 mm Hg at any time in the past

2. Refractive error of more than -6.00 or more than +6.00 sphere or more than 3.00 cylinder with the following exceptions:

- Eyes with more than 6.00 D of myopia but less than 8.00 D of myopia are eligible if: 1) there are no abnormalities on ophthalmoscopy related to myopia that are associated with visual loss (such as staphyloma, retinal thinning in the posterior pole, or more than mild optic disc tilt), and 2) the individual will wear a contact lens for all perimetry examinations with the appropriate correction.

- Eyes with more than 6.00 D of hyperopia but less than 8.00 D of hyperopia are eligible if: 1) there is an unambiguous characteristic halo of peripapillary edema as opposed to features of a small crowded disc or other hyperopic change related to visual loss determined by the Site Investigator or the Photographic Reading Center (PRC) Director (or his designate), and 2) the individual will wear a contact lens for all perimetry examinations with the appropriate correction (which can be corrected for perimetry or with the patient's own contact lens with over correction by lens at the perimeter).

Note: Refractive error exclusion and exceptions refer to sphere not spherical equivalent, with cylinder expressed in plus format.

3. Other disorders causing visual loss except for refractive error and amblyopia, including cells in the vitreous or iritis

4. Large optic disc drusen on exam or known in previous history (small drusen of the disc can occur with longstanding papilledema and are allowed if not so numerous that investigator determines they are contributing to vision loss)