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IdIopathIc intracranial hypertension, or pseudotumor cerebri, is an uncommon condition that most common-ly afflicts young obese females. Typical symptoms of

IIH include daily headache, pulse-synchronous tinnitus, and transient visual obscurations. In more advanced cases papilledema can develop, which can be associated with vision loss and diplopia.39 Idiopathic intracranial hyper-tension is a chronic condition that may worsen after a pe-riod of stability, warranting long-term follow-up.35

Treatment of IIH is directed toward relief of symp-

toms and preservation of vision. Traditional treatment of IIH consists of weight loss, diuretics, and headache prophylaxis. Surgical procedures such as lumboperito-neal, ventriculoperitoneal, or ventriculoatrial shunting and ONSF are reserved for those patients who experi-ence unsuccessful medical management. None of these procedures, however, treat the underlying cause of the in-creased ICP.

Focal stenoses in the dural sinus outflow have been demonstrated in 30%–93% of patients with IIH.12,16,18 These stenoses characteristically occur in the lateral trans verse sinuses and upper sigmoid sinuses, and are likely due to hypertrophied pacchionian granulations in most instances.22 There is increasing evidence that in some patients with IIH, increased ICP is caused by ve-

Dural sinus stent placement for idiopathic intracranial hypertension

Clinical articleDaviD a. Kumpe, m.D.,1,2 Jeffrey L. Bennett, m.D., ph.D.,3,4 Joshua seinfeLD, m.D.,1,2 victoria s. peLaK, m.D.,3,4 ashish chawLa, m.D.,1 anD mary tierney, n.p.1

Departments of 1Radiology, 2Neurosurgery, 3Neurology, and 4Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, Colorado

Object. The use of unilateral dural sinus stent placement in patients with idiopathic intracranial hypertension (IIH) has been described by multiple investigators. To date there is a paucity of information on the angiographic and hemodynamic outcome of these procedures. The object of this study was to define the clinical, angiographic, and hemodynamic outcome of placement of unilateral dural sinus stents to treat intracranial venous hypertension in a subgroup of patients meeting the diagnostic criteria for IIH.

Methods. Eighteen consecutive patients with a clinical diagnosis of IIH were treated with unilateral stent place-ment in the transverse-sigmoid junction region. All patients had papilledema. All 12 female patients had headaches; 1 of 6 males had headaches previously that disappeared after weight loss. Seventeen patients had elevated opening pressures at lumbar puncture. Twelve patients had opening pressures of 33–55 cm H2O. All patients underwent di-agnostic cerebral arteriography that showed venous outflow compromise by filling defects in the transverse-sigmoid junction region. All patients underwent intracranial selective venous pressure measurements across the filling defects. Follow-up arteriography was performed in 16 patients and follow-up venography/venous pressure measurements were performed in 15 patients.

Results. Initial pressure gradients across the filling defects ranged from 10.5 to 39 mm Hg. Nineteen stent procedures were performed in 18 patients. One patient underwent repeat stent placement for hemodynamic failure. Pressure gradients were reduced in every instance and ranged from 0 to 7 mm Hg after stenting. Fifteen of 16 patients in whom ophthalmological follow-up was performed experienced disappearance of papilledema. Follow-up arteriog-raphy in 16 patients at 5–99 months (mean 25.3 months, median 18.5 months) showed patency of all stents without in-stent restenosis. Two patients had filling defects immediately above the stent. Four other patients developed trans-verse sinus narrowing above the stent without filling defects. One of these patients underwent repeat stent placement because of hemodynamic deterioration. Two of the other 3 patients had hemodynamic deterioration with recurrent pressure gradients of 10.5 and 18 mm Hg.

Conclusions. All stents remained patent without restenosis. Stent placement is durable and successfully elimi-nates papilledema in appropriately selected patients. Continuing hemodynamic success in this series was 80%, and was 87% with repeat stent placement in 1 patient. (DOI: 10.3171/2011.10.JNS101410)

Key worDs      •      idiopathic intracranial hypertension      • pseudotumor cerebri      •      stent      •      dural sinus      •      venous sinus      •      hydrocephalus

Abbreviations used in this paper: AVM = arteriovenous mal-formation; BMI = body mass index; ICP = intracranial pressure; IIH = idiopathic intracranial hypertension; ONSF = optic nerve sheath fenestration.

See the corresponding editorial in this issue, pp 536–537.

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nous outflow obstruction due to these lesions. Recent re-ports have focused on treatment of these outflow stenoses with stent placement.1,3,7,11,15,24–27,29,31,33,40 Currently, there are 42 cases of stent placement for IIH in the literature. Stenting has shown a 100% technical success rate, and intracranial sinus pressures were invariably reduced by stenting among the reported cases. While short-term clin-ical follow-up has been favorable, there are very limited follow-up data on the hemodynamic performance of the stented dural sinus system.5,13,32

Since 1999, we have treated 18 patients with IIH with 19 stenting procedures of the dural sinuses. Clini-cal follow-up is available in all of these patients. Follow-up angiographic studies are available in 16 patients, and follow-up venous manometry in 15. These patients are the basis of this report.

MethodsFrom February 1999 to November 2009, 18 patients

were treated with 19 stenting procedures (Table 1). All patients had a clinical diagnosis of IIH. All patients had papilledema and 17 of 18 had visual disturbance. All pa-tients had undergone unsuccessful medical management.

Patient DemographicsThere were 6 men and 12 women in the study sample

(Table 1). Ages ranged from 16 to 62 years. All 12 female patients had headaches: 10 chronic, 1 intermittent, and 1 subacute (3 weeks). One of 6 male patients had head-aches that disappeared after he lost weight. All patients had papilledema at some time in their clinical course, and 17 had papilledema at the time of the procedure. One of these patients had papilledema with acute retinal hem-orrhages. Symptom duration ranged from 3 weeks to 20 years (median 28.5 months). Four patients were referred for urgent stent placement because of rapidly deteriorat-ing vision in the form of central field loss associated with an afferent pupillary defect.

Seventeen patients were reported to have elevated opening pressures (≥ 25 cm H2O) on lumbar puncture. Two patients had opening pressures of 25 and 26 cm H2O, and 12 patients had opening pressures between 33 and 55 cm H2O. Three patients had elevated opening pressures reported, but the values were not available. One patient had no lumbar puncture opening pressure reported.

Prior Surgical ProceduresPrior to stent placement, 3 patients had ventriculo-

peritoneal shunts placed (Cases 1, 6, and 8) and 7 had undergone 8 total ONSFs, 1 bilateral (Case 9) and 6 uni-lateral (Cases 1, 5, 8, 11, 12, and 15).

Five of 7 patients undergoing ONSF had deteriora-tion of vision in the operated eye after ONSF. There was immediate worsening of visual acuity in 2 cases. Case 5 noted initial improvement but then deterioration in visual acuity in the operated eye within 1 month. Another 2 pa-tients (Cases 9 and 12) suffered catastrophic vision loss in the operated eye within 1 and 2 months of the operation, respectively. The patients who had deterioration of vision

after ONSF had further deterioration of central visual acuity. Deterioration of vision after ONSF was believed to be due to ongoing injury to the optic nerve of uncer-tain origin. Three of these patients underwent emergency stent placement within 1, 1, and 2 months of failed ONSF to prevent vision loss in the remaining eye. Five patients’ eyes had optic nerve atrophy at presentation; all had un-dergone ONSF. Three eyes developed nerve atrophy fol-lowing ONSF and 2 had atrophy prior to ONSF.

Body Mass IndexBody mass indices ranged from 22.6 to 38 kg/m2

(Table 1). Sixteen (88%) of 18 of patients were overweight or obese. Twelve patients (67%) had BMIs ≥ 30 kg/m2 (obese), and 4 had BMIs of 26–30 kg/m2 (overweight).

Neuroimaging StudiesInterpretations were available for 17 scans performed

on 15 patients. Five patients had 6 CT venograms, 8 had MR venograms, and 2 had MR venograms and CT veno-grams. All scans showed filling defects in the transverse-sigmoid junction regions. However, in 7 patients (11 scans) studies were interpreted as normal with no mention of the filling defects. The defects were specifically described in 3 scans on 3 patients.

Dural Sinus AnatomyEight patients had right dominant transverse/sigmoid

sinuses, while 4 had left dominant systems. Six had right and left transverse/sigmoid sinuses of equal size. Filling defects were present at the transverse-sigmoid junction in all patent dural sinuses. There was asymmetrical su-perficial versus deep venous drainage, in which the deep system drained into the nondominant side, and the super-ficial system drained into the dominant side, in 9 of 12 patients with a dominant sinus.

Operative ProceduresNineteen stent procedures were performed. One pa-

tient had 2 separate stent placements after a hemodynam-ic failure of the first stenting procedure.

All patients underwent diagnostic cerebral arteriog-raphy, venous manometry, and selective intracranial dural sinus venography. The dural sinuses were depicted in a minimum of 4 angiographic projections to visualize their entire length, particularly in the transverse-sigmoid junc-tion region.

For intracranial dural sinus pressure measurements, a guiding catheter was placed in the internal jugular vein on the side that appeared to be most appropriate anatomi-cally for stenting, according to arteriography and scan-ning studies. A large-bore microcatheter (0.025-inch in-ner lumen) was advanced through the guiding catheter to its tip, where venous pressure is measured through the microcatheter. Under subtraction fluoroscopy, the micro-catheter was then advanced into the posterior superior sagittal sinus. Pressure was measured in the lower supe-rior sagittal sinus, the torcular, transverse, and sigmoid sinuses, and internal jugular vein. In some patients, we have also measured pressures on either side of the filling

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defects in both transverse/sigmoid sinuses. After pressure measurements, intracranial sinus venography was per-formed.

When a significant pressure gradient existed across the filling defect, the patient was brought back on a sepa-rate occasion for elective stent placement. In 4 patients (Cases 2, 7, 9, and 12), 3 of whom were referred for ur-gent or emergency stenting, we performed stent place-ment at the time of the first examination. The patient was placed under general anesthesia for all stent procedures. A 6 Fr guide sheath (Shuttle, Cook Inc.) was advanced over a glide wire (Terumo Medical Corporation) into the sigmoid sinus. A 0.018-inch system self-expanding stent (Precise, Codman Neurovascular; Acculink, Guidant-Boston Scientific; or Zilver, Cook Inc.) was then deployed across the stenosis under roadmap imaging. Postdilation of the stent has not been necessary in our experience. Pressure measurements were repeated from the torcular herophili through the internal jugular vein to document that the gradient had decreased.

Patients were placed on 75 mg per day of clopidogrel and 325 mg per day of aspirin for at least 5 days pre-ceding the stent placement and for 6 months after stent placement. After 6 months, the clopidogrel was discontin-ued and the patients were continued on aspirin. Follow-up angiography with venous pressure measurements was

performed with the patient awake using the technique described above (Fig. 1).

Stent ProceduresOf the 19 stenting procedures, stents were placed in

the right transverse-sigmoid junction region on 12 occa-sions and on the left side on 7 occasions. Two balloon-expandable stents were placed on 1 occasion, while single self-expanding stents were used in all other cases except 1 in which 2 self-expanding stents were required to cover the narrowed segment. Stent diameters ranged from 6 to 10 mm, and stent lengths ranged from 24 to 80 mm. Six-teen stents were 8–10 mm in diameter. The most common stent lengths were 40 mm (8 cases) and 30 mm (6 cases). Stents were placed in the dominant sinus in 17 patients and in the nondominant sinus in 1 patient.

ResultsPressure Gradients

All stent placement procedures were successful. Prestent venous pressure gradients were recorded for 16 patients when awake. Gradients between the torcular he-rophili and the internal jugular vein ranged from 10.5 to 39 mm Hg (Table 2). The median gradient was 21.1 mm

TABLE 1: Patient demographics*

Case No.

Age at Stent Placement (yrs), Sex Headache

Vision Disturbance

Duration ofSymptoms (mos) BMI (kg/m2)

Lumbar Puncture Opening Pressure

(cm H2O) Shunt Placed ONSF

1 41, F yes yes 240 38 36 multiple shunts w/ infec- tion pre- and post- stent

lt

2 16, F yes yes 0.75 22.6 >50 none none 3 58, M no yes 27 28.2 elevated none none 4 30, M no yes 12 31.9 36 none none 5 52, M no yes 4 26 33 none rt

6a 25, F yes yes 72 elevated yes 2001 none6b (stent 2) yes yes 37.9 yes none

7 59, F yes yes 78 26.2 34 none none 8 28, F yes yes 72 28.6 33 multiple yes 9 27, F yes yes 4.5 33.9 43.5 none bilat10 62, M no yes 27 24.4 34 none none11 22, F yes yes 30 36.4 55 none rt12 58, F yes yes 10 35.8 44 none rt13 36, F yes yes 35 31.1 25 none none14 23, F yes yes 2.5 31.3 >50 none none15 44, M no at present; h/a in

2005 before weight loss

lt > rt 36 33.4 elevated none lt

16 23, F yes yes 60 34.4 55 none none17 53, M no no 120 37.8 26 none none18 26, F yes yes 12 30.9 not available none none

* All patients had papilledema. Abbreviation: h/a = headache.

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Hg and the average gradient was 21.5 mm Hg. Fifteen pa-tients had 16 pressure gradients recorded while under an-esthesia (1 patient underwent restenting). Gradients while under anesthesia ranged from 4 to 30 mm Hg, with a me-dian of 10 mm Hg and mean of 13.7 mm Hg. Among 13 patients who underwent recordings both while awake and under general anesthesia, the pressure gradient decreased during anesthesia in 11 and increased in 2. Poststent pres-sure gradients improved immediately in all patients. Pres-

sure gradients immediately after placement were reduced to 0–7 mm Hg (Table 2).

Transit TimeAs an angiographic indicator of hemodynamic im-

provement immediately following stent placement, the transit time on internal carotid arteriography was record-ed from the time of first appearance of contrast material at the catheter tip to first appearance of contrast at the

Fig. 1. Case 5. Images from a 52-year-old man with progressive, rapidly decreasing visual acuity over 4 months. He under-went right ONSF 6 weeks prior to presentation. A: Digital subtraction angiogram of the right internal carotid artery, left anterior oblique projection, venous phase showing outflow almost exclusively via the left transverse sigmoid sinuses. The right transverse sinus and sigmoid sinus are small and receive drainage almost exclusively from the straight sinus. There was a pressure gradient (ΔP, between the torcular herophili and internal jugular vein) of 21 mm Hg across the filling defects in the left transverse sinus and transverse-sigmoid junction (patient awake). Arrows indicate venous pressures of 34 and 13 mm Hg in the lower superior sagittal sinus and torcular herophili compared with the lower left sigmoid sinus and upper left internal jugular vein. B: Left transverse sinus venogram before stent placement, with the patient under anesthesia. Pressure gradient was 8 mm Hg. The filling defect in the transverse sinus and transverse-sigmoid junction are evident. C: Left transverse sinus venogram immediately after place-ment of two 10 mm × 30 mm Precise stents. Pressure gradient was 0. The residual filling defect at the lower end of the stent (arrow) has no gradient across it. D: Digital subtraction angiogram of the right internal carotid artery, venous phase, obtained 41.5 months after stent placement. The stent is patent without restenosis. Pressure gradient is 1.5 mm Hg. The patient’s right eye acuity remains abnormal, but improved from initial presentation, and the left eye vision is normal. There is no papilledema.

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jugular foramen. Among 14 patients in whom this infor-mation was available, transit time decreased acutely in 11 (79%) and was unchanged in 3. For example, in Case 7 transit time decreased from 8.42 seconds to 6.33 seconds, a 25% decrease. In 7 patients, transit time decreased by 18%–26%, and in 2 patients by 12%. In another 2 patients, transit time decreased by 1 second, although the specific times were not recorded.

ComplicationsThere were 1 major and 2 minor complications. One

patient developed a urinary tract infection. This same pa-tient had a brief syncopal episode when transferring from the bed to a chair the morning after stent placement.

One patient had a concomitant small parasagittal brain AVM. She was referred for urgent stent placement after a failed ONSF in which she became functionally blind in the operated eye over the following month. Ur-gent transcatheter obliteration of the AVM followed by stent placement, was performed to preserve vision in the remaining eye. The patient had also developed occlusion of the left sigmoid sinus during the month after ONSF. During stent placement, there was transient stasis of flow in the solitary right sigmoid sinus. The patient developed a left subdural hematoma and subarachnoid hemorrhage, managed with placement of a ventriculostomy catheter. The subdural hematoma resolved spontaneously within 24 hours. At 6 months after stent placement the patient

was normal except for trace right foot weakness believed to be secondary to curative embolization of the AVM.

Clinical Follow-UpClinical follow-up was available in all patients and

ranged from 11 to 136 months (median 30 months, mean 43.7 months). Sixteen patients have undergone follow-up fundoscopic examinations. The examining ophthalmolo-gist was aware that the patients had undergone dural sinus stent placement. Papilledema resolved in 15 (94%) of 16 patients (Table 3) and has not recurred. Visual acuity in-formation before and after stent placement was available in 15 patients. Visual acuity remained stable or improved in every patient. Visual acuity did not improve from base-line in the eyes that had deteriorated vision either from optic nerve atrophy or following ONSF. Follow-up lum-bar punctures were not obtained because of the increased incremental risk of hemorrhage among these patients who were all receiving daily clopidogrel and aspirin.

Among the 12 female patients, all of whom had head-ache at presentation, headaches resolved in 2 (Cases 6 and 12) and were present but improved (decreased intensity and frequency, with a different pattern) in 8 (Cases 2, 7, 9, 11, 13, 14, 16, and 18; Table 3). Headaches were un-changed in 2 cases. Thus, 10 of 12 patients had persistent headache in some form, even though they improved in 8 of the 10. No male patient had headaches before or after stent placement.

TABLE 2: Pressure gradients across the stenosis*

Case No.

Venous Pressure Gradient (mm Hg) Interval from Stenting to Last

Angiogram (mos)

Venous Pressure Gradient (mm Hg)Before Stent Placement

During Anesthesia

After Stent Placement At Last Follow-Up

Change From Immediate Poststent Measurement

1 NA 14 3 72 NA NA 2 22 NA 6 99 5.5 −0.5 3 22 14 7 NA NA NA 4 17.5 24 2 21.5 2 0 5 21 8 0 41.5 1.5 1.5 6 NA 10 1 10.5 10.5 9.5 (hemodynamic failure)

6 (restent) 10.5 7 0 25.5 0 0 7 18 NA 3 7.3 4 1 8 16.5 9 3 25 5.5 2.5 9 20 30 4 29.5 5 110 22 7 1 5 2 111 27 10 3 NA NA NA12 NA 28 5 7.5† 8 313 16 10 0 24.5 2.5 2.514 39 9 1 6.5 4.5 3.515 16.5 NA 3 8.5 3 016 23 14 3 6 10.5 7.517 24.5 21 1.5 9 2.5 118 22 4 1 8 18 17

* NA = not available.† Patient underwent CT angiography at 15.5 months that showed continuing patency of the stent without any restenosis. No venous pressures were available at this time.

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Angiographic and Hemodynamic Follow-UpSixteen patients underwent 29 follow-up catheter

arteriograms and 1 CT arteriogram between 5 and 99 months (median 18.5 months, mean 25.3 months). All stents were patent with no in-stent restenosis. In 2 patients (Cases 9 and 12) there were intraluminal filling defects immediately adjacent to the upper end of the stent. In retrospect, the filling defects were present at the time of stent placement and were not covered completely by the stent. This was a technical error. In 4 patients (Cases 6, 8, 16, and 18) there was a tapered narrowing of the trans-verse sinus as it approached the stent, without an intralu-minal filling defect. The transverse sinus above the stent was widely patent in the remaining 10 patients.

In 15 patients there were also 28 venous pressure determinations during follow-up. Pressure gradients be-tween the torcular herophili and the internal jugular vein at the last follow-up ranged from 0 to 18 mm Hg. In 12 patients (80%), the change from the gradient immediately after stent placement was less than 4 mm Hg, including the 2 patients who had a filling defect above the stent (Fig. 2). Three of the 4 patients with tapered narrowing of the transverse sinus above the stent had significant hemody-namic failure, with changes from the immediate poststent gradient of 7.5–17 mm Hg. One of these patients (Case 6), who experienced recurrence of the original gradient of 10.5 mm Hg, underwent restenting with elimination of the gradient. Two other patients (Cases 16 and 18) who developed narrowing of the transverse sinus above the stent had pressure gradients of 10.5 and 18 mm Hg at follow-up, compared with prestent gradients of 23 and 22 mm Hg and immediate poststenting gradients of 3 and

1 mm Hg, respectively (Fig. 3). None of these patients developed recurrent papilledema.

RetreatmentTwo patients required retreatment. One patient (Case

6) underwent placement of a second stent into the nar-rowed transverse sinus 11 months after the initial stent placement because her gradient of 10 mm Hg had com-pletely recurred. Follow-up venous manometry 15 months after placement of the second stent showed a zero gra-dient.

At the time of the initial stent placement, one patient (Case 2) had a subacute thrombosis of her right transverse sinus that could not be recanalized using a transcathe-ter technique. The stent was placed in her stenotic left transverse-sigmoid junction with a decrease in her pres-sure gradient from 22 to 6 mm Hg. A hypercoagulability syndrome that was not characterized was diagnosed in this patient. Seventy months after stent placement, and 1 month after a stillbirth, she developed thrombosis of the left sigmoid sinus downstream from the stent. The throm-bus was successfully cleared using transcatheter intracra-nial thrombolysis and mechanical thrombectomy, with restoration of the original poststenting gradient. There was no stenosis within the stent. At 99 months follow-up, angiography and venous manometry showed a pat-ent stent with a pressure gradient equal to the original postenting gradient.

TABLE 3: Clinical outcome at follow-up

Case No.

Clinical Inter- val (mos) Papilledema Headache

1 136 unchanged unchanged 2 99 resolved improved 3 76 resolved none to begin with 4 71.5 resolved none to begin with 5 41.5 resolved none to begin with 6 54 resolved resolved (after 2nd stent) 7 42 resolved nearly com-

pletelyimproved

8 38 resolved unchanged 9 29.5 resolved rt eye improved10 30 resolved none to begin with11 27 NA improved12 30 resolved resolved13 24.5 resolved improved14 30 resolved improved15 16.5 resolved rt eye none to begin with16 18 resolved improved17 11.5 resolved none to begin with18 11 resolved improved

Fig. 2. Case 9. Internal carotid artery angiogram, lateral oblique view, venous phase of a filling defect immediately above the stent, 30 months after placement of a 10 mm × 40 mm Zilver stent in a 27-year-old woman. The patient was 18 weeks pregnant at the time of stent placement. She had undergone bilateral ONSFs 2 months previously, after which her left eye vision rapidly deteriorated from 20/20 to 20/200. She was referred for urgent stent placement to preserve right eye acu-ity. The filling defect above the stent (arrow) was noted in retrospect after stent placement. The poststent gradient rose from 4 to 8.5 mm Hg at 18 months after stenting, and then fell to 5 mm Hg at 30 months after stent placement. Papilledema has not recurred. The decision was made at the present time to not perform repeat stent placement. Her visual acuity remains 20/20 in the right eye, with no change in the left eye.

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DiscussionAnatomical Considerations

Stenoses in the lateral transverse sinuses are com-monly found in patients with IIH. Farb et al.2,12 found that more than 90% of patients with IIH undergoing imaging using a specialized MR venography (auto-triggered el-liptic-centric-ordered 3D Gd-enhanced MR venography) demonstrated evidence of sinovenous stenoses. There is controversy as to whether stenoses in the lateral trans-verse sinuses are a primary cause of elevated ICP or a result of increased ICP. Disappearance of stenoses in the transverse sinuses and transverse-sigmoid sinus junctions after shunting or lumbar puncture have been documented by several investigators2,21,33 who assert that the phenom-enon is secondary to increased ICP. Conversely, Bono et al.4 followed 14 patients with IIH and transverse sinus stenoses and found no change in the anatomical narrow-ing despite normalization of CSF pressure in 64% of the patients. The explanation of these contradictory findings may be secondary to the presence of 2 patient popula-tions in IIH, one with truly IIH and one with intracra-nial hypertension caused by venous outflow obstruction.17 These distinct populations are apparent in the study by Farb et al.,12 who noted 2 types of dural sinus narrowing in patients with IIH: 1) long, smooth-tapered narrowing secondary to external compression from swollen brain parenchyma; and 2) acutely “marginated” (clearly demar-cated with a sharply defined margin) intraluminal filling defects secondary to enlarged, partially obstructing intra-luminal arachnoid granulations.

Intraluminal filling defects are common in the lateral sinuses. Leach et al.22 found discrete filling defects within the dural sinuses on 138 (24%) of 573 contrast-enhanced CT examinations in a nonselect group of patients, and in 13 (13%) of 100 contrast-enhanced MR studies. These

defects are focal, well defined, and typically located ad-jacent to venous entrance sites. Arachnoid granulations were observed in 66% of 29 cadaveric specimens in a similar distribution. They concluded that these are nor-mal structures and should not be confused with a sinus thrombosis or intrasinus tumor. Significant bilateral ob-struction of venous outflow may ultimately trigger the onset of IIH.

It is our opinion, shared by others,5,11,16 that patients who have a clinical diagnosis of IIH should undergo non-invasive scanning studies, either MR venography or CT venography, to look for anatomical evidence of dural sinus abnormality, either bilateral filling defects in the trans-verse-sigmoid junction region or unilateral hypoplasia of the transverse and/or sigmoid sinus with a filling defect in the contralateral patent transverse/sigmoid sinus. The clinician should review the studies because filling defects in the transverse sinus region are commonly present and might not be described in the radiology report. Fifteen patients in this series had filling defects on either CT ve-nography, MR venography, or both, but in 7 of 15 patients the studies were interpreted as normal with no mention of the filling defects. We believe that patients with such fill-ing defects should undergo diagnostic arteriography and venous manometry. The angiographic/manometric diag-nostic workup in our experience has been safe and with-out complications. Patients who will respond to unilateral stenting have intraluminal filling defects with a pressure gradient precisely across the filling defect.

Clinical ConsiderationsAll patients in this series had a clinical diagnosis of

severe IIH producing papilledema and 17 of 18 had visual disturbance. Four developed unilateral blindness. Three patients had rapidly progressive vision loss shortly fol-lowing ONSF and were referred for urgent stent place-

Fig. 3. Case 18. Digital subtraction angiograms of the left internal carotid artery, venous phase, obtained in a 26-year-old woman with a new headache pattern for 1 year, receiving chronic narcotics, found to have papilledema. A: The pressure gradi-ent was 22 mm Hg across the filling defect in the left transverse-sigmoid junction (patient awake). B: The pressure gradient was 1 mm Hg immediately after stent placement. C: Eight months after stenting the pressure gradient was 18 mm Hg, with a tapered narrowing of the lateral transverse sinus above the stent (arrow).

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ment. Another patient had become blind in 1 eye previ-ously. All had increased intracranial venous pressure with a pressure gradient localized across a filling defect in the treated transverse-sigmoid junction. Two patients had oc-clusion of a sigmoid sinus. All patients received unilateral stents. In our experience, bilateral stenting was not nec-essary. All stent placements were technically successful, with an immediate decrease in the pressure gradient.

Our clinical follow-up ranged from 11 to 136 months. Half of the patients had follow-up of more than 30 months. No patient experienced visual deterioration from baseline after stent placement. Papilledema resolved in 15 (94%) of 16 patients, with no recurrence in follow-up. Two patients did not have fundoscopic examination fol-lowing stent placement; in both patients visual symptoms improved.

Headaches persisted in some form in 10 of 12 female patients, although 8 of the 10 had decreased frequency and severity of the headaches, which also had a differ-ent pattern from that at presentation. Continued headache in patients with IIH after successful treatment is not un-common. In 1 series of patients with IIH treated using shunt procedures, 95% had significant improvement in headache immediately after shunt placement. However, 48% of patients with a functioning shunt had recurrence of their headaches at 3 years.23 Friedman and Rausch14 noted that, among a series of 82 patients with IIH, 67% had persistent headaches despite successful treatment for increased ICP.

Angiographic and Hemodynamic ConsiderationsThe minimum pressure gradient at which stenting

will produce significant clinical benefit has not been es-tablished. In our experience, the maximum normal pres-sure gradient between the torcular herophili and the inter-nal jugular vein is 4–5 mm Hg, which is compatible with published figures.20 We set an arbitrary pressure gradient of 10 mm Hg as the lower limit of when stenting was to be performed. All patients in this series had a pressure gradient of at least 10 mm Hg.

This study suggests that stenting is a durable proce-dure. All stents studied angiographically have remained patent, and the longest study interval was 99 months. No patient has experienced a recurrent stenosis within the stent. The only reocclusion developed as an acute dural sinus thrombosis in the sigmoid sinus below the stent, at 70 months after stent placement. This patient had had a prior episode of dural sinus thrombosis and was believed to have a hypercoagulable state.

Hemodynamic improvement was sustained in 13 of 15 patients studied with venous manometry in follow-up. Twelve patients had no or minimal (< 4 mm Hg) hemody-namic deterioration at 8–96 months after a single stenting procedure, while 1 patient underwent repeat stent place-ment.

Three patients with hemodynamic deterioration de-veloped narrowing of the transverse sinus above the stent with no intraluminal filling defect. The cause of the nar-rowing is not clear. These 3 patients may have had pri-mary idiopathic intracranial hypertension rather than ve-

nous obstruction as a cause of their increased ICP, despite the findings on diagnostic arteriography and selective intracranial venous pressure measurements. Rohr et al.33 published a widely quoted single stenting failure similar to our 3 cases, associated with recurrence of symptoms. The stenosis was documented on CT and MR imaging, without follow-up angiographic or hemodynamic stud-ies. The incidence of development of hemodynamic de-terioration across a new narrowing above the stent is 20% (3 of 15 patients with hemodynamic follow-up) in this series. In 1 of these 3 patients, who underwent re-peat stent placement, there is continued hemodynamic success without new narrowing above the second stent. None of the patients with hemodynamic deterioration has developed recurrent papilledema to date. No other such stenting failures have been reported. At present we do not have a fixed limit of pressure gradient recurrence above which we will perform repeat stent placement. We are following these patients’ clinical status. If they redevelop papilledema or visual changes, we will perform restent-ing of the narrowed segment above the stent. Of note, the mode of hemodynamic failure in these 3 patients does not involve a problem with the stented segments, which have universally remained patent without restenosis, but with the dural sinus above the stent. More experience with the procedure should refine patient selection criteria. It is an open question whether primary stenting of the transverse sinus as well as the focal narrowing at the transverse-sig-moid junction eliminates this possibility.

Comparison With Reported Experience With StentingOur outcomes of stent placement are comparable

with those in the literature, with longer follow-up. There are 42 reported cases of stent placement for IIH. These cases consist of 4 series of 4, 10, 10, and 12 patients7,11,15,27 and 6 individual case reports.1,26,29,31,33,40 The literature re-sults have been tabulated in 2 recent reports.1,40 In this reported experience, technical success has been 100%. Between 10% and 42% of patients have been asymp-tomatic in follow-up, and 58%–100% of patients either asymp tomatic or improved. One patient, cited above, had clinical failure within 1 week associated with a change in Doppler velocities.33 Clinical follow-up has been reported from 2 to 60 months, with 6 patients followed for longer than 24 months7,11,15 and only 2 patients followed for lon-ger than 36 months. There is almost no information about stent patency or the hemodynamic performance of the stented venous system in follow-up. Our clinical results (100% technical success, 89% with either no or improved headaches, and 94% with resolution of papilledema) are comparable with reported results, and with a longer clini-cal follow-up of up to 136 months (mean 43.7 months, median 30 months). In addition, we have angiographic follow-up studies for as long as 99 months in 16 patients, and hemodynamic follow-up studies in 15 patients, which indicate that both angiographic patency and the hemody-namic result of stenting are durable. One retreatment was performed because the transverse sinus became narrowed above the stent with recurrence of the original pressure gradient. Two other patients (13%) developed hemody-

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namic deterioration—although not to their baseline pres-sure gradients—associated with narrowing of the trans-verse sinus above the stent.

There is 1 report of in-stent restenosis in a dural si-nus stent. The restenosis occurred at 6 months following placement of a stent in a tight sigmoid sinus stenosis in a patient with an untreated AVM associated with venous hypertension.38 In our opinion this is a different hemody-namic situation that does not pertain to patients with IIH due to outflow stenosis.

Serious complications from stent placement have been rarely reported in the literature. Higgins et al.15 re-ported thrombosis in 2 stents shortly after stent place-ment, treated by thrombolysis. Our serious complication of intracranial hemorrhage due to transient venous out-flow occlusion occurred during an urgent stent placement to attempt to preserve vision in a patient who had rapidly lost vision in 1 eye following ONSF. In the future, in a similar situation, we would consider performing a surgi-cal cutdown of the anterior superior sagittal sinus to allow antegrade placement of the stent without compromising the outflow, as has been mentioned by Owler et al.28

Comparison With Results of Conventional TherapyAmong patients who have appropriate anatomy for

stent placement, as in this series, outcomes appear to be more durable and successful than standard medical or surgical results. All current medical and surgical treat-ments have a significant long-term failure rate. All surgi-cal procedures have a potential for early complications.

Medical management of IIH is appropriate for pa-tients without severe papilledema and/or visual deteriora-tion and is not free of risk. In a study of 20 patients with IIH followed for at least 10 years and managed medically, 45% had either delayed worsening or recurrence of their visual symptoms and papilledema.35 Another study with a mean observation of 6.2 years showed a 38.4% recur-rence rate of IIH.19

Patients with papilledema have a more severe mani-festation of IIH that can permanently damage their optic nerves and are frequently referred for a surgical proce-dure to preserve vision. Surgical management involves either a shunt procedure (lumboperitoneal, ventriculo-peritoneal, or ventriculoatrial) or ONSF.

Surgical shunts have a high failure rate. Patients un-dergoing ventriculoperitoneal or lumboperitoneal shunt placement frequently require 1 or more shunt revisions within 3 years of placement. In a review of a 30-year ex-perience of shunt placement for headache due to IIH at a single institution, McGirt et al.23 discussed 115 shunt placement procedures in 42 patients. Eighty percent of all shunts in this study required revision within 36 months. Cumulative failure at 1 year was 75% for lumboperitoneal shunts and 50% for ventriculoperitoneal and ventricu-loatrial shunts. Ninety-five percent of patients experienced a significant improvement in their headaches immediately after the shunt was inserted. However, severe headache re-curred despite a properly functioning shunt in 20 patients (48%) at 36 months. Papilledema was present in 60% of patients before shunt placement. There was no informa-tion about relief of papilledema.

Optic nerve sheath fenestration has been considered by some investigators to be more effective for treatment of papilledema with fewer complications than lumboperito-neal shunting.8,10,34 However, follow-up studies have indi-cated that ONSF is not as effective as originally believed.6 Optic nerve sheath fenestration is associated with signifi-cant complications, with as many as 40% in 1 series.30 As many as 33% of patients who have initial improve-ment in visual symptoms after ONSF for IIH experience deterioration of visual acuity and visual fields.36,37 In the series by Corbett et al.10 with 40 ONSFs in 26 patients, 6 patients (15% of eyes, 23% of patients) lost vision within 2 weeks of surgery. Five of the 6 had no vision return after lumboperitoneal shunting. One-third of patients undergo-ing ONSF have no relief of headaches. Shunting may still be required in these patients. Patients treated with ONSF must be followed carefully. Only approximately 75% of ONSFs appear to be functioning 6 months after surgery. The probability of functioning of ONSF steadily decreas-es thereafter, so that 66% are functioning at 12 months, 55% at 3 years, 38% at 5 years, and 16% at 6 years af-ter surgery.36 The incidence of complications increased significantly with repeat ONSF.6,9 Our experience in this series is consistent with the data in literature. Seven pa-tients had undergone 8 total ONSFs. Five of these patients had deterioration of vision in the operated eye either im-mediately or within 2 months of surgery, and 2 patients became blind in the operated eye.

Thus, even though either shunting or ONSF may ini-tially improve vision and prevent acute deterioration of vi-sion in patients with IIH, both have significant early com-plication rates and high long-term failure rates, requiring repeat procedures. In contrast, stent placement appears to be a safer procedure initially, and more durable in follow-up. Papilledema, in particular, disappeared after the in-tracranial venous pressure gradient was eliminated by the stent. The hemodynamic success in 87% of patients and continued patency in 100% of the stents in our series sug-gest that the stabilization or improvement in vision may be durable without the need for repeat procedures.

Headache control following stent placement was less satisfactory. A similar phenomenon has been observed in patients who have undergone a shunt procedure or ONSF. The persistence of headache in some form among our fe-male patients with IIH suggests that stenting may offer no advantages for headache relief compared with shunting. On the other hand, the persistent headaches in all these patients may simply reflect the more severe nature of their clinical syndrome, because all had papilledema.

ConclusionsOur experience indicates that there is a subgroup

of patients meeting the diagnostic criteria of IIH who have focal dural sinus outflow obstruction that causes a substantial and documentable pressure gradient, in turn causing intracranial hypertension with papilledema. Nor-malization of this pressure gradient with stent placement results in resolution of the papilledema. Therefore, these patients have elevated ICP due to their venous sinus ste-nosis and are not “idiopathic.” We believe that stenting

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Dural sinus stents for idiopathic intracranial hypertension

547

is the initial procedure of choice in this patient subgroup because it is safer and more durable than conventional surgical therapy. The proportion of this subgroup within the entire IIH population remains to be established.

Disclosure

Dr. Kumpe has received royalties from Cook, Inc.Author contributions to the study and manuscript preparation

include the following. Conception and design: Kumpe, Seinfeld. Ac quisition of data: all authors. Analysis and interpretation of data: Kumpe, Bennett, Seinfeld, Pelak. Drafting the article: Kumpe, Sein-feld. Critically revising the article: Kumpe, Seinfeld. Statistical anal-ysis: Kumpe. Administrative/technical/material support: Kumpe, Seinfeld. Study supervision: Kumpe, Seinfeld.

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Manuscript submitted August 17, 2010.Accepted October 24, 2011.Please include this information when citing this paper: published

online December 9, 2011; DOI: 10.3171/2011.10.JNS101410.Address correspondence to: David Kumpe, M.D., Department

of Radiology, 12401 East 17th Avenue, Mail Stop L-954, Aurora, Colorado 80045. email: david.kumpe@ucdenver.edu.