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Keywords:

  • Pseudotumour cerebri;
  • idiopathic intracranial hypertension;
  • ventriculoperitoneal shunt;
  • lumboperitoneal shunt;
  • optic nerve sheath fenestration;
  • venous sinus thrombosis

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

To review the literature on the surgical treatment of idiopathic pseudotumour cerebri (PTC) [idiopathic intracranial hypertension (IIH)]. When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The main procedures performed include lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF). Recently, venous sinus stenting procedures have been performed on selected patients with PTC, especially those with venous sinus occlusive disease. The literature is summarized and appraised in the form of a narrative review. It is evident that ONSF, LPS, VPS and, in selected cases, venous sinus stenting may improve vision and prevent deterioration of vision in patients with PTC. All of the procedures have their advantages and disadvantages and may fail with time no matter what procedure is used. Various authorities have vehemently advocated one or the other of these procedures. Until a prospective, randomized study comparing ONSF with LPS or VPS for PTC is performed, and until the role of venous sinus obstruction as the aetiology of PTC is better defined, the question of which surgical procedure is best for the treatment of PTC remains unanswered.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

Pseudotumour cerebri (PTC) is a syndrome of increased intracranial pressure without hydrocephalus or mass lesion and with normal cerebrospinal fluid (CSF) composition. This syndrome is often considered to be ‘idiopathic’[‘idiopathic PTC’ or ‘idiopathic intracranial hypertension (IIH)’]. Recently, Friedman and Jacobson have re-defined the diagnostic criteria for idiopathic cases to include (1):

  • • 
    If symptoms are present, they may only reflect those of generalized intracranial hypertension or papilloedema
  • • 
    If signs are present, they may only reflect those of generalized intracranial hypertension or papilloedema.
  • • 
    Documented elevated intracranial pressure measured with the patient in the lateral decubitus position.
  • • 
    Normal CSF composition.
  • • 
    No evidence of mass, structural, or vascular lesion on magnetic resonance imaging (MRI) or contrast-enhanced computed tomography (CT) for typical patients, and MRI and MR venography (MRV) for all others.
  • • 
    No other cause of intracranial hypertension identified.

In all cases of presumed PTC, obstruction or impairment of intracranial venous drainage must be considered as a mechanism for cerebral oedema with increased intracranial pressure and papilloedema. Tumours that occlude the posterior portion of the superior sagittal sinus or other cerebral venous sinuses may cause increased intracranial pressure, as may septic or aseptic thrombosis or ligation of the cavernous sinus, lateral sinus, sigmoid sinus, or superior sagittal sinus (2, 3). Ligation of one or both jugular veins (e.g. during radical neck dissection for regional tumors), thrombosis of a central intravenous catheter in the chest or neck, subclavian vein catheterization and arteriovenous fistula, haemodynamically significant left-to-right cardiac shunt from a cardiac septal defect, the superior vena cava syndrome, or a glomus jugulare tumour impairing venous drainage may also cause increased intracranial pressure (4–6). Venous sinus thrombosis may be the mechanism of PTC reported with systemic lupus erythematosus, essential thrombocythaemia, protein S deficiency, antithrombin III deficiency, the antiphospholipid antibody syndrome, paroxysmal nocturnal haemoglobinuria, Behçet's disease, meningeal sarcoidosis, hypervitaminosis A, mastoiditis, and other disease processes (7–9).

Biousse et al. noted that central venous thrombosis (CVT) can present with all the classic criteria for idiopathic PTC, including normal CT imaging and CSF contents (10). Of 160 consecutive patients with CVT, 59 (37%) presented with isolated intracranial hypertension. Neuroimaging revealed involvement of more than one venous sinus in 35 patients (59%), and CT imaging was normal in 27 of 50 patients (54%). The superior sagittal sinus was involved in 32 patients (54%; isolated in seven) and the lateral sinus in 47 (80%; isolated in 17). The straight sinus was thrombosed in eight patients, cortical veins were involved in two, and deep cerebral veins in three, always in association with thrombosis in the superior sagittal sinus or lateral sinuses. Lumbar puncture was performed in 44 patients and showed elevated opening pressure in 25 of 32 (78%) and abnormal spinal fluid contents in 11 (25%). Aetiological risk factors included local causes (n = 7), surgery (n = 1), inflammatory disease (n = 18), infection (n = 2), cancer (n = 1), postpartum (n = 1), coagulopathies (n = 11) and oral contraception (n = 7). The cause was unknown in 11 cases (19%). The authors emphasized that MRI and MRV should be considered in presumed isolated intracranial hypertension. In another prospective study of 24 patients with apparently idiopathic PTC, angiography disclosed CVT in six (11).

A study by Johnston et al. reported a retrospective analysis of the evidence of cranial venous outflow pathology in 188 patients with PTC syndrome investigated over the period 1968–1999 (12). Standard methods of investigation appropriate to the period were used, i.e. cerebral angiography, CT and MR scanning. A subgroup (25 patients) was investigated for haematological abnormalities. The overall incidence of cranial venous outflow abnormality was 19.7% (37 cases). A cause of the venous abnormality was identified in 20 cases, most commonly haematological and iatrogenic. In 17 patients (all female) no cause was identified. Fifteen of the 25 patients (60%) tested specifically were found to have a haematological abnormality, although no correlation was shown between this and a demonstrable venous outflow abnormality. The conclusion was drawn that there is a high incidence of venous outflow abnormalities in PTC syndrome with detailed investigation.

Farb et al. determined the prevalence and nature of sinovenous structural abnormalities in idiopathic PTC using auto-triggered elliptic–centric–ordered three-dimensional gadolinium-enhanced MRV (ATECO MRV) (13). ATECO MRV consists of a three-step process: (i) two-dimensional, single-slice scanning at the level of the cavernous sinus for automatic detection of the arrival of a power-injected i.v. bolus of contrast material in the carotid arteries; (ii) an 8-s delay to allow for arterial-to-venous transit of the contrast agent; and (iii) a fast three-dimensional gradient echo MR sequence optimized to quickly capture the contrast material in the venous vascular phase of the first pass of the contrast agent. The resultant images are post-processed with the maximum intensity projection algorithm to produce an MR venogram. In this study, the patency of the transverse and sigmoid dural venous sinuses was graded using the combined venous conduit score (CCS). The CSS, the sum of the right and left scores, was the highest degree of stenosis from the torcula to the distal sigmoid sinus on a 0–4 scale [0 = discontinuity or aplasia, 1 = hypoplasia or severe segmental stenosis (< 25% stenosed), 2 = moderately stenosed (25–50%), 3 = mildly narrowed segment (50–75%), and 4 = no significant narrowing (75–100%)]. The CSS generally ranged from 2 to 8. Farb and colleagues prospectively studied 29 idiopathic PTC patients and 59 control patients. Substantial bilateral sinovenous stenoses were seen in 27 of 29 patients with idiopathic PTC and in only four of 59 control patients. Using ATECO MRV, they could identify idiopathic PTC patients with 93% sensitivity and specificity. Farb et al. speculate that idiopathic PTC is due to two components. The first is the primary, otherwise unsuspected abnormality such as a congenital narrowing of the transverse sinus (TS). Secondarily, increased CSF pressure related to idiopathic PTC could exacerbate the underlying venous sinus abnormality and create a flow-limiting stenosis and resultant pressure gradient. This could exacerbate the elevation of the intracranial pressure. In an accompanying editorial to Farb et al.'s study, Silberstein et al. noted that the use of three-dimensional contrast-enhanced MRV technique (ATECO MRV) in the evaluation of PTC patients may indicate ‘the death of idiopathic intracranial hypertension’(14). They state that if the findings of the study under consideration hold true, narrowed venous conduits appear to be a relatively sensitive and specific criterion for the diagnosis of idiopathic PTC and that > 90% of patients with idiopathic PTC have stenotic TSs. Farb et al.'s technique offers considerable benefits over time-of-flight and phase contrast techniques commonly employed in clinical practice currently. Thus, three-dimensional contrast-enhanced MRV may become the imaging procedure of choice to improve diagnostic confidence for suspected cases of idiopathic PTC.

Cerebral venous sinus thrombosis accounted for 9.4% of patients with presumed idiopathic PTC in three tertiary care neuro-ophthalmology services (15). MRV in combination with MRI is recommended to identify this subgroup of patients.

Increased blood flow and venous hypertension have also been implicated as the mechanism of papilloedema noted in some patients with cerebral arteriovenous malformations (AVMs), especially dural AVMs and fistulas (16). Thus, we consider MRV (and, in selected cases, MR angiography or even formal angiography) warranted to investigate the possibility of venous sinus occlusion in patients with PTC, especially in patients with features not typical for idiopathic PTC (e.g. in thin patients, men, the elderly).

The thought that elevated intracranial venous sinus pressure is a ‘universal mechanism’ for PTC syndrome of varying aetiologies (17) has been called into question in a study by King et al. (18). These authors studied patients with idiopathic PTC and found that when transducer-measured intracranial venous pressure is high, reduction of CSF pressure by removal of CSF predictably lowers the venous sinus pressure. This study, thus, indicates that the increased venous pressure in idiopathic PTC patients is caused by the elevated intracranial pressure, and not the reverse. In an accompanying editorial to this study, Corbett and Digre suggest that ‘the chicken is the CSF pressure elevation and the egg is the venous sinus pressure elevation’(19). The idiopathic narrowing of the venous sinuses noted in the cases of PTC described above may conceivably have been TS compression from increased intracranial pressure. Thus, venous occlusive disease and elevated venous pressure may well not be the mechanism of PTC in most idiopathic cases.

Bono et al. evaluated whether TS stenosis changed after normalization of CSF pressure in patients with idiopathic PTC during medical treatment (20). Fourteen consecutive patients with idiopathic PTC with bilateral TS stenosis on cerebral MRV during the medical treatment were studied. Patients were followed for > 6 years. During the follow-up, patients underwent repeated lumbar punctures (LPs) and cerebral MRV. MRV was always performed before each LP. TS stenosis persisted in all the patients during the follow-up. In nine of 14 (64%) patients with idiopathic PTC, CSF pressure normalized during medical treatment. The authors concluded that TS stenoses, as revealed by MRV, persist in patients with idiopathic PTC after normalization of CSF pressure, suggesting the lack of a direct relationship between the calibre of TS and CSF pressure. Their patients had sinus venous stenosis but a normal CSF pressure. They hypothesize that the narrowing in both TSs alone is not sufficient to raise intracranial pressure and that other unidentified factors may play a role together with TS stenosis in increasing intracranial pressure.

Pseudotumour cerebri may occur in association with the Chiari I malformation (21–23). In a series of 156 cases of PTC reviewed, Chiari malformation occurred with an incidence of 1.3%, rising to 2.7% in patients with MR scanning (21). The association may be coincidental. However, Vaphiades et al. reported four adult women (age range 25–59 years) with bilateral papilloedema and Chiari I malformations who underwent suboccipital decompression (23). In all four patients, surgery was followed by resolution of bilateral papilloedema and signs and symptoms of increased intracranial pressure. These authors suggested that patients with increased intracranial pressure and papilloedema from Chiari I malformation may benefit from suboccipital decompression.

MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

The treatment of PTC has two major goals: the alleviation of symptoms and preservation of visual function. Treatment of PTC is outlined in Table 1. Some patients require no treatment as long as symptoms are minimal and visual function is normal, but all require serial monitoring of visual function, especially visual fields, to observe closely for signs of visual impairment. Weight reduction, including surgically induced weight reduction in morbidly obese patients, may improve the papilloedema and reduce intracranial pressure. Medical treatments for idiopathic PTC include carbonic anhydrase inhibitors (e.g. acetazolamide and topiramate) and loop diuretics. Corticosteroids may be efficacious in the short run, but the complications of this medication, especially in the chronic treatment of an already obese individual, have resulted in most clinicians suggesting that their use be avoided. Repeated lumbar punctures have never been systematically studied for the treatment of PTC. As repeated lumbar punctures are uncomfortable, are of questionable benefit and are potentially associated with complications, we feel that they should not be performed therapeutically except perhaps during pregnancy. Finally, if carbonic anhydrase inhibitors do not control the headache associated with PTC, symptomatic headache treatments are warranted.

Table 1.  Management of idiopathic pseudotumour cerebri (adapted from Lee AG, Brazis PW. Clinical pathways in neuro-ophthalmology. An evidence-based approach, 2nd edn. Thieme: New York, 2003.)
  • *

    Blind spot enlargement should not be considered significant visual loss (refractive).

1. Confirm clinical diagnosis (diagnosis of exclusion)
2. Medical treatment recommendations
 a. Acetazolamide (e.g. Diamox sequels 500 mg qHS for 3 days, then 500 mg b.i.d.—up to 2–4 g/day) if no contraindications
 b. Consider topiramate if acetazolamide intolerant
 c. Other medications have not been proven but may be useful (e.g. lasix)
 d. Avoid corticosteroids if possible (cause weight gain and other side-effects) except possibly i.v. steroids for acute visual loss
3. Explain medication side-effects of acetazolamide
 a. Paraesthesias, anorexia, malaise, tin-like taste, fatigue may limit use
 b. May cause nausea and vomiting, electrolyte changes, kidney stones
 c. Caution during pregnancy
  (1) Relatively contraindicated, especially during first 20 weeks
  (2) Potential teratogenicity (Category C agent)
  (3) Consult with obstetrics and gynaecology if benefit outweighs risk
  (4) Usually avoid diuretics and caloric restriction if pregnant.
4. Encourage weight reduction
5. Treat headache symptomatically
6. Consider diagnosis of and treat associated sleep apnoea (24)
7. Surgical treatment (if fail, intolerant to, or non-compliant with maximal medical therapy) (25)
 a. Optic nerve sheath fenestration
 b. Lumboperitoneal shunt procedure
 c. Ventriculoperitoneal shunt
 d. ?Dural venous sinus stenting
 c. Indications for surgery
  (1) New worsening visual field defect*
  (2) Enlargement of previously existing visual field defect*
  (3) Reduced visual acuity not due to macular oedema
  (4) Presence of severe visual loss (20/40 or worse) in one or both eyes at time of initial examination
  (5) Anticipated hypotension induced by treatment of high blood pressure or renal dialysis
  (6) Psychosocial reasons, such as patient's inability to perform visual field studies, non-compliance with medications, an itinerant lifestyle
  (7) Headache unresponsive to standard headache medications
8. Follow-up visit intervals
 a. Return monthly (similar interval) until disc oedema resolved (usually several months to years)

Patients with IIH without papilloedema are not at risk of visual loss.

Patients with idiopathic PTC without papilloedema are not at risk of visual loss. They are treated by weight loss, headache therapies, and with acetazolamide or topirimate, but surgery for the increased intracranial pressure is rarely, if ever, indicated.

SURGICAL TREATMENT OF PTC

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The indications for surgical therapy, as suggested by Corbett and Thompson (25), are outlined in Table 1. The main procedures performed include lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF). Recently, venous sinus stenting procedures have been performed on selected patients with PTC, especially those with venous sinus occlusive disease. Various authorities have vehemently advocated one or the other procedures, and each has its advantages and disadvantages, but there has been no prospective study comparing the efficacy of these procedures.

LPS FOR PTC

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

Lumboperitoneal shunt can relieve headache, diplopia and papilloedema and can reverse and/or prevent visual loss (26–32). This procedure may be performed if warranted in pregnancy (33). Eggenberger et al. retrospectively studied 27 patients with PTC treated with at least one LPS to ascertain the efficacy of this treatment (28). The indications for LPS were intractable headache in 18 patients (67%) and progressive optic neuropathy in 14 patients (52%). Visual function returned to normal in both eyes of six patients, showed no change in either eye in four patients, and improved in at least one eye in the remaining four. Four patients had unilateral and one had bilateral sixth nerve palsies; all completely resolved post surgery. The average duration of follow-up for this population was 77 months (mean 47 months). A functioning LPS was successful in alleviating symptoms in all of the patients studied, and no patient with a functioning shunt complained of shunt-related symptoms, such as low-pressure headache or abdominal pain, within 2 months after the shunt was performed. The major complication of LPS was shunt failure requiring revision. The authors concluded that placement of a LPS is a satisfactory treatment for the majority of patients with PTC who require surgical therapy for the disorder, even though some patients ultimately require multiple shunt revisions.

Rosenberg et al. reviewed the efficacy of cerebrospinal diversion procedures for PTC in patients from six different institutions (32). Thirty-seven patients underwent a total of 73 LPS and 10 VPSs. Only 14 patients remained ‘cured’ after a single surgical procedure. The average time between shunt insertion and shunt replacement was 9 months, although 64% of the shunts lasted < 6 months. Shunt failure (recurrent papilloedema or increased CSF pressure on lumbar puncture) (55%) and low-pressure headaches (21%) were the most common indications for re-operation. Other reasons for shunt replacement included infection, abdominal pain, radicular pain, operative complications, and CSF leak. The vision of most patients improved (13) or stabilized (13) postoperatively. However, three patients who had initially improved subsequently lost vision, six had a postoperative decrease in vision, two patients improved in one eye but worsened postoperatively in the other, and four lost vision despite apparently adequate shunt function. Shunt failure with relapse of PTC occurred as late as 7 years after insertion. The authors concluded that CSF diversion procedures have a significant failure rate as well as a high frequency of side-effects. Johnston et al. reported 36 patients who during follow-up required a total of 85 shunting procedures, with an overall complication rate of 52% and a failure rate of 48% (29).

Burgett et al. retrospectively analysed clinical data from 30 patients who underwent LPS for PTC and found LPS an effective means of acutely lowering intracranial pressure (27). Symptoms of increased intracranial pressure improved in 82% of patients, and five patients (29%) demonstrated total resolution of all symptoms. Among 14 patients with impaired visual acuity, 10 (71%) improved by at least 2 Snellen lines. Worsening of vision occurred in only one eye. Of 28 eyes with abnormal Goldmann perimetry, 18 (64%) improved and none worsened. The incidence of serious complications was low, but the major drawback was a need for frequent revisions in a few patients (30 patients underwent a total of 126 revisions with the mean revision rate of 4.2 per patient). The authors suggested that LPS should be considered the first surgical procedure for patients with PTC with severe visual loss at presentation or with intractable headache (with or without visual loss). After shunting it is important to identify patients who are shunt intolerant (27).

Thus, LPS is often effective in controlling PTC, and although placement of the shunt is in general safe, any operation performed under general anaesthesia carries some risk, and there is at least one perioperative death reported following LPS (34). The use of shunting prodedures (VPS and LPS) for idiopathic PTC is increasing in the USA (35). Shunt obstruction is the most common complication of LPS (27, 28, 32, 36–38), followed by secondary intracranial hypotension caused by excessive drainage of the CSF via the LPS (27–30, 32, 36–39). The recent availability of a programmable LPS apparatus may result in a lower incidence of symptomatic intracranial hypotension. Symptoms of intracranial hypotension include nausea and vomiting, nuchal rigidity, disturbances of vision, vertigo, tinnitus, and reduced hearing (the latter three are thought due to a decreased intra-labyrinthine pressure gradient across the cochlear aqueduct). Complications of LPS are listed in Table 2.

Table 2.  Complications of lumboperitoneal shunts (adapted from Lee AG, Brazis PW. Clinical pathways in neuro-ophthalmology. An evidence-based approach, 2nd edn. Thieme: New York, 2003.)
• Abdominal pain, bowel perforation, or migration or dislocation of the peritoneal end of the catheter (28, 31, 36–38)
• Tonsillar herniation (acquired Chiari I malformation) (symptomatic or asymptomatic) and syringomyelia (36, 37, 40, 41)
• Infection (32, 38)
• Low pressure symptoms (e.g. positional headache, etc.) (32, 38)
• Subdural haemorrhage
• Subarachnoid haemorrhage and intracerebral haematoma (42)
• Visual loss from retinal ischaemia
• Bilateral visual loss and simultagnosia from bilateral parieto-occipital infarction related to rupture of a previously asymptomatic intracranial aneurysm after LPS (43)
• Rarely death (34)

VPS for PTC

Ventriculoperitoneal shunt is another possible treatment for PTC. McGrit et al. have reported results of VPS for PTC (44). Between 1973 and 2000, 21 consecutive patients received 79 LPSs for PTC-associated intractable headache. Between 2000 and 2004, 21 consecutive patients underwent 36 VPS surgeries with frameless stereotactic image guidance despite the absence of ventriculomegaly in all patients. Shunt revision and complication rates were compared between LPS and VPS, and predictors of treatment failure (continued headache despite properly functioning shunt) were assessed using proportional hazards regression analysis. Forty patients (95%) experienced significant improvement of headache immediately after shunting. Severe headache recurred despite properly functioning shunt in eight (20%) and 20 (48%) patients 12 and 36 months after initial shunt surgery. Patients without papilloedema (n = 17) or with symptoms for > 2 years (n = 19) were fivefold and 2.5-fold more likely to experience headache recurrence. LPS vs. stereotactic VPS was associated with a 2.5-fold increased risk of shunt revision, because of a 2.8-fold increased risk of shunt obstruction, but had a similar risk of overdrainage, distal catheter migration and shunt infection. The authors concluded that shunts were extremely effective at acutely treating PTC-associated intractable headache, providing long-term relief in the majority of patients. Lack of papilloedema and long-standing symptoms were risk factors for treatment failure. This is the first comparison of stereotactic VPSs vs. LPSs and suggests that VPSs placed with image-guided stereotaxy are associated with lower risks of shunt obstruction and revision. According to these authors, using stereotactic VPS in patients with papilloedema should be considered for patients with PTC-associated intractable headache.

In another study, McGirt et al. reviewed the records of all shunt placement procedures that were performed for intractable headache due to PTC at one institution between 1973 and 2003 (45). Using proportional hazards regression analysis, predictors of treatment failure (continued headache despite a properly functioning shunt) were assessed, and shunt revision and complication rates were compared between LPS and ventricular [ventriculoperitoneal (VP) or ventriculoatrial (VAT)] shunts. Forty-two patients underwent 115 shunt placement procedures: 79 in which an LP shunt was used and 36 in which a VP or VAT shunt was used. Forty patients (95%) experienced a significant improvement in their headaches immediately after the shunt was inserted. Severe headache recurred despite a properly functioning shunt in eight (19%) and 20 (48%) patients by 12 and 36 months, respectively, after the initial shunt placement surgery. Seventeen patients without papilloedema and 19 patients in whom preoperative symptoms had occurred for > 2 years experienced recurrent headache, making patients with papilloedema or long-term symptoms fivefold [relative risk (RR) 5.2] or 2.5-fold (RR 2.51) more likely to experience headache recurrence, respectively. In contrast to VP or VAT shunts, LPSs were associated with a 2.5-fold increased risk of shunt revision (RR 2.5) due to a threefold increased risk of shunt obstruction (RR 3.95%), but there were similar risks between the two types of shunts for overdrainage (RR 2.3), distal catheter migration (RR 2.1) and shunt infection (RR 1.3). The authors concluded that, based on their 30-year experience in the treatment of these patients, shunts were extremely effective in the acute treatment of PTC-associated intractable headache, providing long-term relief in the majority of patients. Lack of papilloedema and long-standing symptoms were risk factors for treatment failure. The use of ventricular shunts for PTC was associated with a lower risk of shunt obstruction and revision than the use of LP shunts. They suggested that using ventricular shunts in patients with papilloedema or symptoms lasting < 2 years should be considered for those with PTC-associated intractable headache.

Bynke et al. reported a series of 17 patients treated with VPS for idiopathic PTC that were followed up for 1.8–12.8 years (mean 6.5 years) (46). The ventricular catheter was inserted without any guidance device. VPS was effective on all clinical manifestations of idiopathic PTC. Seven patients required one or two (a total of nine) surgical revisions. The revision rate was significantly less than in two similar series of patients treated with LPS. Papilloedema resolved within 0.6–7.0 months (mean 3.1 months). Visual acuity improved by more than two lines in three eyes, remained unchanged and < 1.0 in six eyes, and was 1.0 before and after surgery in 20 eyes. Non-significant changes (increase or decline by one or two lines) occurred in five eyes. Visual fields returned to normal in 11 eyes, improved in 11 eyes and remained unchanged in 12 eyes. The other symptoms and signs resolved. The high-pressure headache resolved in all patients, in most patients immediately after shunt implantation. Four patients developed low-pressure headache due to overdrainage. This was resolved by increasing the opening pressure of the valve. During a follow-up time of 1.8–12.8 years (mean 6.5 years), seven patients required one or two (a total of nine) surgical revisions. All revisions were undertaken within 1.9 years (mean 0.5 year) after the first shunt implantation. One revision was made because of malposition of the ventricular catheter, six because of failures of the peritoneal catheter, and two because of suspected shunt infection. Bacterial cultures were negative. The survival time of the last shunt was 1.8–12.8 years (mean 6.3 years).

Woodworth et al. reported 21 patients who underwent 32 ventricular shunting procedures (20 VP, 10 ventriculoatrial, two ventriculopleural) for PTC (47). One hundred percent of shunts were successfully placed into slit ventricles, all requiring only one pass of the catheter under stereotactic guidance to achieve the desired location and CSF flow. There were no procedure-related complications and each ventricular catheter showed rapid egress of CSF. All (100%) patients experienced significant improvement of headache immediately after shunting. Ten percent of ventricular shunts failed at 3 months after insertion, 20% failed by 6 months, 50% failed by 12 months and 60% failed by 24 months. Shunt revision was due to distal obstruction in 67%, overdrainage in 20% and distal catheter migration or CSF leak in 6.5%. There were no shunt revisions due to proximal catheter obstruction or shunt infection. The authors concluded that frameless stereotactic ventricular CSF shunts were extremely effective at treating PTC-associated intractable headache and continued to provide relief in nearly half of patients 2 years after shunting without many of the shunt-related complications that are seen with LPSs. Placing ventricular shunts using image-guided stereotaxis in patients with PTC despite the absence of ventriculomegaly was an effective, safe treatment option.

Abu-Serieh et al. reviewed the medical charts of nine consecutive patients (mean age 26.4 years, range 4–63 years) treated using either a frame-based or frameless stereotactic ventriculoperitoneal shunting (SVPS) technique for idiopathic PTC (48). The mean postoperative follow-up period was 44.3 months (range 6–110 months). Before shunting procedures were performed, each patient presented with intractable headache, and five patients (55.6%) had mild to moderate visual deficits. The last follow-up assessment showed that after shunting was performed, eight patients (89%) were headache free. Only one patient had recurrent headache; however, this patient's pain was much less frequent and severe than before the shunting procedure was completed and was concomitant with recent weight increase. Visual deficits were resolved in three patients and remained stable in two who already had optic nerve atrophy before shunting was completed. Twelve SVPS procedures were performed on our patients. Nine shunt revisions were needed in six patients because of infection (n = 5, including two revisions in one patient), valve dysfunction (n = 2), distal obstruction (n = 1) and ventricular catheter malpositioning (n = 1). No patient had proximal catheter obstruction. Given the favourable long-term outcome of the SVPS technique for refractory idiopathic PTC, the authors were encouraged to apply this procedure on their patients and suggested that more invasive approaches should be reserved for patients who have SVPS failure.

Table 3 compares the advantages and disadvantages of LPS vs. VPS in patients with PTC.

Table 3.  Lumboperitoneal shunt (LPS) vs. ventriculoperitoneal shunt (VPS) in pseudotumour cerebri (PTC)
• Both control headache, papilloedema, visual loss, and other PTC signs and symptoms
• LPS
 – Requires more revisions
 – Increased risk of shunt obstruction
 – Low-pressure headache difficult to treat but may be avoided by programmable shunt
• VPS
 – Revisions less often required
 – Shunt obstruction less often than with LPS
 – Low-pressure headache controlled by programmable shunt
 – But, requires craniotomy—risk of stroke, haemorrhage, infection, seizures, etc.

ONSF FOR PTC

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

Optic nerve sheath fenestration has been proven to prevent deterioration in vision and, in some cases, improve visual function in patients with PTC (49–69). For example, in one study 28 patients underwent 40 ONSFs for relief of visual loss or to preserve vision (16 unilateral and 12 bilateral operations) (59). Papilloedema disappeared or was strikingly reduced in 24 of 28 patients. The other four patients had gliotic discs (two patients) or were followed up for only a short time. Visual acuity improved in 12 of 40 eyes and remained the same in 22 of 40 eyes. In six eyes, visual acuity decreased. The visual fields improved in 21 of 40 eyes and remained the same in 10 eyes; five of the 10 eyes that did not change had poor vision before surgery. Eight eyes in five patients continued to lose acuity postoperatively. An additional two eyes developed visual field loss with preserved visual acuity. In another study, 23 patients with chronic papilloedema had ONSF, and 21 of the 23 patients demonstrated improvement in visual function (64). Twelve of 21 patients with bilateral visual loss had improved visual function bilaterally after unilateral surgery, and six of 21 patients needed bilateral surgery. ONSF improved vision in six patients who failed to recover vision after LPS.

Kelman et al. performed ONSF on 17 patients with severe visual acuity or field loss (57). Postoperatively, visual acuity improved or stabilized in 33 of 34 eyes (97%) and the visual fields improved in 20 of 21 eyes that underwent surgery. Kelman et al. also performed ONSF in 12 patients (16 eyes) with functioning LPS and progressive visual loss (58), and all patients demonstrated improvement in visual function. Pearson et al. operated on nine patients (14 eyes), and visual function showed significant improvement or stabilized in all but one patient (63). Spoor et al. performed ONSF in 53 patients (101 eyes) with PTC and visual loss (67). Sixty-nine eyes (85 patients) with acute papilloedema uniformly had improved visual function after ONSF. Of the 32 eyes with chronic papilloedema (18 patients), only 10 improved. Thirteen eyes required secondary or tertiary ONSF after an initial successful result. Eleven of 13 eyes had improved visual function after repeat ONSF. Goh et al. described 29 eyes of patients with PTC who underwent ONSF for visual loss in spite of acetazolamide treatment (55). Visual acuity and visual fields were compared before and after operation (within 1 and 6 months). The mean follow-up of this study was 15.7 months (range 1–50 months). Visual acuity improved in four eyes (14%), was unchanged in 22 (76%) eyes and worsened in three (10%) eyes. Visual fields improved in 10 (48%) eyes, remained unchanged in eight (38%) eyes and worsened in three (14%) eyes (six lost to follow-up). There were four repeat surgeries in which vision was lost in one eye.

Banta et al. reported 158 ONSFs in 86 patients with PTC with visual loss despite medical treatment (70). Visual acuity stabilized or improved in 148 of 158 (94%) eyes, and visual fields stabilized or improved in 71 of 81 (88%) eyes. Surgical complications, most often benign and transient, occurred in 39 of 86 patients. Diplopia occurred in 30 patients with 87% resolving spontaneously (two patients required prismatic correction and two patients underwent subsequent strabismus surgery). Only one eye in one patient had permanent severe visual loss (count fingers acuity) secondary to an operative complication (presumed traumatic optic neuropathy). One patient had total ophthalmoplegia and blindness after surgery (orbital apex compression syndrome) that completely resolved over 1 month with steroid therapy. Visual loss occurred in 16 of 158 (10%) eyes after initially successful primary ONSF with time from surgery to failure variable (up to 5 years post surgery). No specific risk factors that predisposed patients to ONSF failure were discovered. Nine eyes in six patients underwent repeat ONSF for progressive visual loss after an initially successful ONSF. The only complication encountered on repeat ONSF was transient diplopia in two patients. Two patients who underwent repeat ONSF required a CSF diversion procedure to halt progressive visual loss, and two patients with stable visual function after repeat ONSF required CSF diversion procedures for intractable headaches. Three patients with progressive visual loss after initially successful primary ONSF underwent CSF diversion procedures instead of repeat ONSF. After ONSF, many patients initially had symptomatic improvement of headaches, but only eight of 61 (13%) patients with headache as a presenting symptom had subjective improvement. Nine patients underwent CSF diversion procedures for intractable headaches after ONSF despite stable visual parameters. The authors noted that the patient population with a significant headache component would be likely to benefit from an initial CSF diversion procedure. The authors concluded that ONSF is a safe and effective means of stabilizing visual acuity and visual fields in patients with PTC with progressive visual loss despite maximum medical therapy (70).

Mittra et al. examined changes in colour Doppler imaging before and after ONSF for PTC (62). Their results suggest that some of the visual loss from chronic papilloedema may be due to ischaemia, and worsening visual acuity correlates with greater impairment of the retrobulbar circulation. One of the mechanisms by which ONSF improves visual function may thus be reversal of this ischaemic process.

Talks et al. reported 24 patients with PTC who required ONSF (68). Twenty-one of the 48 eyes (44%) had macular changes, including choroidal folds (nine patients), circumferential (Paton's) lines (four patients), nerve fibre layer haemorrhages (three patients), macular stars (five patients), macular oedema (six patients), retinal pigment epithelial changes (four patients) and subretinal haemorrhage leading to a macular scar (one patient). Significant visual loss attributable to the macular changes was found in five eyes in the short term and three eyes in the long term. The two eyes that improved had macular stars; of the three eyes that did not improve, two had retinal pigment epithelial changes and one had subretinal haemorrhage leading to a macular scar. The authors concluded that the majority of macular changes in PTC patients resolve and do not add to visual loss from optic nerve damage. Patients with marked macular oedema, however, are at the most risk for permanent visual loss and should be considered for early surgical treatment.

Chandrasekaran et al. studied 51 eyes of 32 patients with PTC by chart review and comparison of preoperative and postoperative examinations. The main outcome measures included visual fields, visual acuity, and complications (71). Postoperative visual field mean deviation scores improved within 6 months when compared with preoperative visual fields. Multiple regression analysis demonstrated that eyes with mean deviation ≥ −20 dB were associated with improved or stabilized visual acuity at 6 months [odds ratio (OR) 7.5]. Eyes with visual field defects outside 10 degrees of fixation were associated with improved or stabilized visual fields at 6 months (OR 9.7). Five patients developed self-limiting complications from surgery.

Yazici et al. evaluated morphological changes occurring in the retrobulbar region after optic nerve sheath decompression (ONSD) in patients with idiopathic PTC using MRI (69). This study included 26 eyes of 17 patients (age range 9–57 years) with idiopathic PTC who underwent ONSD. The surgery was performed through transconjunctival medial orbitotomy and by a dural window excision. After ONSD, the optic nerves were examined with MRI by means of three-dimensional ‘constructive interference in steady state’ sequence. After ONSD, papilloedema resolved in all eyes and visual functions improved in all except one. Early postoperative MRI (2–8 weeks after surgery) demonstrated a cyst-like fluid collection adjacent to the dural window site in nine (75%) of 12 eyes and a fibrous tissue formation in three eyes (25%). Late postoperative MRI (6–15 months after surgery) demonstrated a fibrous tissue formation at the decompression site in 25 eyes (96%) and perioptic fluid collection in one eye (4%). The authors concluded that in the early postoperative period after ONSD, a fluid collection adjacent to the decompression site occurs in most eyes; this finding disappears in the late period. Early postoperative MR findings support the idea that ONSD functions through CSF filtration.

Optic nerve sheath fenestration has also been affective in children with PTC (60). Of 12 patients with PTC (< 16 years of age) reviewed, 66% had improved visual acuity, 33% had improved visual fields and 17% had worsening of visual acuity and visual fields postoperatively (60).

Headaches may be relieved in over half of the patients with PTC undergoing ONSF (25, 54). For example, with unilateral decompression, headaches were improved or were relieved in 13 of 17 patients in one series (64) and in 10 of 16 patients in another study (54), whereas 91% of patients (10/11) had relief of headache after ONSF in a third study (72). ONSF may also relieve papilloedema and improve vision when performed on patients with PTC secondary to occlusion of the dural sinuses (56, 62).

Thus, some reports have suggested that ONSF is more effective and associated with fewer complications than LPS (54, 64). Because of these reports, many physicians have abandoned LPS in favour of ONSF for the majority of their patients with PTC that require surgery (28). However, long-term follow-up data suggest that ONSF may not be as effective as originally claimed, and up to 33% of patients undergoing ONSF for PTC who show initial improvement in visual function later show deterioration in visual field and acuity (65, 66). In a study of the long-term effectiveness of ONSF for PTC, Spoor and McHenry reviewed 32 series of postoperative visual fields in patients who were undergoing ONSF for PTC who had stable visual acuity and four or more fields during 6–60 months' follow-up (65). The authors then extended the review to include all patients (54 patients, 75 eyes) who underwent ONSF for PTC, who were followed up with serial automated perimetry. Fifty-two eyes (68%) showed improvement (36%) or stabilization (32%) of visual function, whereas 24 eyes (32%) experienced deterioration of visual function after an initially successful ONSF. The probability of failure from 3 to 5 years was 0.35 by life-table analysis. The authors concluded that ONSF effectively stabilizes or improves visual function in the majority of patients with PTC and visual loss. However, it may fail at any time after surgery, and patients need to be followed up routinely with automated perimetry to detect deterioration of visual function. Some of these late failures may be prevented by better and different operative techniques (64, 66). Also, Acheson et al. reported 14 patients (11 with idiopathic PTC and three with dural venous sinus occlusion) who underwent eight unilateral and six bilateral ONSFs (49). Visual acuity and fields either improved or stabilized in 17 out of 20 eyes, and three deteriorated. Of the eight patients undergoing unilateral surgery, the other eye remained stable in seven and deteriorated in one. Four patients required ONSF despite previous shunting or subtemporal decompression. Five patients required shunting or subtemporal decompression after ONSF because of persistent headache in three cases and for uncontrolled visual failure in two cases. No patient lost vision as a direct complication of surgery.

Thus, vision can be saved after shunt failure, and in other cases may be maintained without the need for a shunt. Shunting may still be required, however, after ONSF, especially for persistent headache. Mauriello et al. reviewed the records of 108 patients with pseudotumour who underwent ONSF and showed visual loss within 1 month of surgery (61). Five patients, including two with renal failure and hypertension, had visual loss within 1 month of ONSF. The first had an abrupt decrease in vision 6 days after ONSF, and in this patient a vessel on the nerve sheath bled into the surgical site. After high-dose i.v. steroids failed to improve vision, emergency LPS resulted in full visual recovery. An apparent infectious optic neuropathy developed in the second patient 3 days after surgery. After 72 h of i.v. antibiotics, visual acuity improved from 20/600 to 20/15. The other three patients had gradual visual loss after ONSF, which stabilized after LPSs. These authors reviewed ONSF failures in the literature and showed that four of seven patients with abrupt visual loss within the first 2 weeks of ONSF had no improvement in vision despite various treatments, including shunts. Corbett et al.'s series of 40 ONSFs in 28 patients included six who lost vision within the first 2 weeks of surgery (54). Only one of these six patients had return of vision, and this patient had a dramatic decrease of vision from 20/30 in the involved eye to no light perception (NLP) 3 h postoperatively after retrobulbar haemorrhage, with acuity improving to 20/20 after surgical drainage of the retrobulbar haematoma. The other five patients had no visual recovery despite LPS, continuous lumbar drainage, and repeat ONSF in one patient described who had intrasheath haemorrhage due to coughing (this patient went from 20/30 to 20/200 10 days postoperatively). Intravenous steroids appeared to enhance visual recovery in one patient of Flynn et al., who went from 20/400 to NLP 5 h postoperatively, but who improved to 20/800 after i.v. dexamethasone (73). Mauriello et al. concluded that avoidance of bleeding during ONSF may prevent fibrous occlusion of the surgical site, and that patients with no identifiable cause for visual loss after ONSF, who do not respond to i.v. steroids, should be evaluated for emergency LPS (61). Also, postoperative infectious optic neuropathy should be considered in the differential of abrupt visual loss after ONSF. If ONSF fails, the authors favour LPS rather than repeat ONSF.

Numerous complications have also been reported after ONSF (54, 73–78). Plotnik and Kosmorsky reported postoperative complications in 15 of the 38 eyes (40%) undergoing ONSF (75). Temporary motility disorders (due to extraocular muscle damage or damage to their nerve or blood supply) occurred in 29%, and all resolved, the longest by 9 weeks. Pupillary dysfunction occurred in four eyes (11%) and consisted of sectoral tonic pupils (due to damage to short ciliary nerves or their blood supply causing iris sphincter palsy) that lasted 2–8 weeks in three eyes but persisted in one eye for 12 weeks. Four eyes (11%) had postoperative vascular complications, including two with central retinal artery occlusions, one supertemporal branch retinal artery occlusion, and one episode of transient outer retinal ischaemia. Both eyes with the central retinal artery occlusions had poor visual outcomes, and eyes that had undergone prior ONSF were significantly more likely to have vascular complications than those without a previous operation. The incidence of vascular complications was 67% in eyes that had undergone prior ONSF and 6% in those that had never undergone a previous ONSF. The complications reported with ONSF are listed in Table 4.

Table 4.  Complications of optic nerve sheath fenestration (adapted from Lee AG, Brazis PW. Clinical pathways in neuro-ophthalmology. An evidence-based approach, 2nd edn. Thieme: New York, 2003.)
  1. References: (51, 54, 70, 73–78).

• Ocular motility disorders (e.g. temporary horizontal motility disorder caused by disinsertion of the medial rectus muscle or combined third and sixth nerve palsies)
• Transient or permanent diffuse or sector tonic pupils
• Conjunctival blebs with dellen formation
• Chemosis
• Chorioretinal scar from excessive traction on the globe
• Peripapillary haemorrhages thought secondary to short ciliary vessel injury
• Orbital haemorrhage
• Trauma to the optic nerve
• Myelinated nerve fibres (noted 5 months and 6 years postoperatively thought stimulated by trauma associated with surgery dellen)
• Microhyphaemas
• Orbital apex syndrome (? steroid responsive)
• Optic nerve cyst formation with proptosis, pain and vision loss
• Subconjunctival Tenon's cysts
• Streptococcal corneal ulcers
• Dacryocystitis
• Intraoperative angle closure glaucoma
• Deterioration of visual function, transient blindness, choroidal infarction (fundus changes with choroidal infarction may not be evident for several weeks after operation
• Central or branch retinal artery occlusion
• Death

From the above summary, it is evident that ONSF, LPS and VPS may improve vision and prevent deterioration of vision in patients with PTC (Class II–III, Level B data). All of the procedures have their advantages and disadvantages and all may fail with time no matter what procedure is used. Approximately one-third of patients undergoing ONSF will not experience headache relief and only about 75% of ONSFs appear to be functioning 6 months after surgery. The probability of functioning of ONSF steadily decreases thereafter, so that 66% are functioning at 12 months, 55% at 3 years, 38% at 5 years and 16% at 6 years after surgery (65). Thus, these patients must have their visual function followed for years, as deterioration may require repeat procedures for ONSF failures. Although patients may be treated with a second ONSF after initial failure, eyes that have more than one ONSF are less likely to improve after surgery and more likely to experience significant vascular complication than are eyes that undergo a single surgery (75). On the other hand, LPS is fraught with many complications, although headache due to PTC is probably better controlled by LPS. Also, LPS failure is common, although most shunt failures occur within 2–3 months of the initial LPS (cumulative risk 37%) and only rarely is the first shunt revision required > 1 year after initial LPS (28). Thus, a patient with PTC who undergoes a LPS and who maintains a functioning shunt for > 1 year has a lower risk of requiring a shunt revision over subsequent years (28). However, patients undergoing LPS also need careful follow-up after their procedure because of the possibility of late failures. LPS failure has been reportedly successfully treated by repeat LPS or by ONSF.

DURAL VENOUS SINUS STENTING FOR PTC

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

Dural venous sinus stenting has been tried as a treatment in some patients with PTC (79). Higgins et al. presented a case of PTC thought secondary to bilateral transverse sinus stenosis discovered on venography that was treated successfully by inserting a self-expanding stent across the stenosis in the right transverse sinus (80). These authors suggest that the transverse sinus pathology was not thrombosis but an idiopathic narrowing of the transverse sinus bilaterally. Owler et al. described a 38-year-old woman, previously diagnosed with PTC and unsuccessfully treated 10 years previously, who re-presented with spontaneous CSF rhinorrhoea (81). Imaging revealed dramatic changes of chronically raised CSF pressure and a defect in the anterior cranial fossa. The CSF leak was corrected surgically, and a LPS was inserted to correct a large postoperative subgaleal CSF collection. Direct retrograde cerebral venography demonstrated venous sinus obstruction due to a filling defect. This was associated with a pressure gradient and high superior sagittal sinus pressure. The venous sinus obstruction was successfully treated with a venous sinus stent and the LPS was removed. The authors feel that chronically raised CSF pressure in untreated cases of PTC may cause widespread changes in the skull, which in this case culminated in a spontaneous CSF leak despite relatively mild headache and visual symptoms. Higgins et al. further reported 12 patients with refractory idiopathic PTC who had dilation and stenting of the venous sinuses after venography, and manometry had shown intracranial venous hypertension proximal to stenoses in the lateral sinuses (82). Intrasinus pressures were recorded before and after the procedure and correlated with clinical outcome. Intrasinus pressures were variably reduced by stenting. Five patients were rendered asymptomatic, two were improved, and five were unchanged. The authors concluded that the importance of venous sinus disease in the aetiology of idiopathic PTC is probably underestimated and that lateral sinus stenting shows promise as an alternative treatment to neurosurgical intervention in intractable cases. Owler et al. investigated the role of cerebral venous sinus disease in PTC and the potential of endoluminal venous sinus stent placement as a new treatment (83). Nine consecutive patients in whom diagnoses of PTC had been made underwent examination with direct retrograde cerebral venography (DRCV) and manometry to characterize the morphological features and venous pressures in their cerebral venous sinuses. The CSF pressure was measured simultaneously in two patients. If patients had an amenable lesion they were treated using an endoluminal venous sinus stent. Five patients demonstrated morphological obstruction of the venous TSs. All lesions were associated with a distinct pressure gradient and raised proximal venous sinus pressures. Four patients underwent stent insertion in the venous sinuses and reported that their headaches improved immediately after the procedure and remained so at 6 months. Vision was improved in three patients, whereas it remained poor in one despite normalized CSF pressures. The authors concluded that patients with PTC should be evaluated with DRCV and manometry because venous TS obstruction is probably more common than is currently appreciated. In patients with a lesion of the venous sinuses, treatment with an endoluminal venous sinus stent is a viable alternative for amenable lesions. Hunt et al. also reported two cases of cerebral venous sinus thrombosis with papilloedema and visual loss that improved after endovascular stent placement (84), and Ogungbo et al. reported successful endovascular stenting of the TS in a single patient with right TS occlusion causing PTC (85).

Higgins et al. reported a patient with PTC who failed to be improved by balloon angioplasty of the lateral sinuses (86). She declined venous sinus stenting. Three months later, she had a LPS inserted due to severe headaches, papilloedema, and bilateral inferior arcuate visual field loss. Papilloedema resolved, but severe headaches persisted. Repeat venography was performed to exclude residual venous obstruction and showed that the sinus stenoses had resolved. Repeat MRV now also appeared normal. She remained symptomatic with headaches but no papilloedema. McGonigal et al. reported resolution of transverse sinus stenosis in idiopathic PTC after LPS (87). CT venography performed before shunting demonstrated severe narrowing of both distal transverse sinuses with no evidence of intracranial venous sinus thrombosis. CT venogram was repeated 6 days after shunt insertion and showed marked reduction in the degree of TS narrowing bilaterally. Rajpal et al. have also reported a single case of a 15-year-old boy who presented with headache, papilloedema, decreased visual acuity, and diploplia who underwent successful unilateral transverse sinus stenosis stenting and experienced complete resolution of symptoms (88).

Thus, some cases of PTC secondary to venous sinus obstruction may be successfully treated using venous sinus stenting. Karakalios et al., however, found that angioplasty or thrombolytic infusion improved outlet obstruction but not the clinical picture of idiopathic PTC (17). It is still unclear if primary treatment of the observed stenosis benefits patients with idiopathic PTC. This should be no surprise, as it is not certain whether the stenoses are the cause or the result of idiopathic PTC.

SUMMARY OF SURGICAL TREATMENT FOR PTC

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References

It is evident that ONSF, LPS, VPS and, in selected cases, venous sinus stenting, may improve vision and prevent deterioration of vision in patients with PTC. All of the procedures have their advantages and disadvantages and all may fail with time no matter what procedure is used. Various authorities have vehemently advocated one or the other procedure. Until a prospective, randomized study comparing ONSF with LPS or VPS for PTC is performed and until the role of venous sinus obstruction as the aetiology of PTC is better defined, the question of which surgical procedure is best for the treatment of PTC will remain unanswered.

References

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MEDICAL TREATMENT OF IDIOPATHIC PTC (IIH)
  5. SURGICAL TREATMENT OF PTC
  6. LPS FOR PTC
  7. ONSF FOR PTC
  8. DURAL VENOUS SINUS STENTING FOR PTC
  9. SUMMARY OF SURGICAL TREATMENT FOR PTC
  10. References