SCOTTSDALE, ARIZ. – Venous sinus stenting remains a controversial treatment for headache associated with benign intracranial hypertension. Opponents highlight potentially serious adverse effects and a lack of rigorous studies on the procedure, while supporters describe it as safe and effective. Experts recently debated the procedure at a symposium sponsored by the American Headache Society.
Which came first?
Stenting is based on the rationale that lowering venous sinus pressure might lower intracranial pressure, said Dr. Deborah Friedman, a neuro-ophthalmologist at the University of Texas Southwestern Medical Center in Dallas.
“Other surgical techniques create a fistula the body wants to close,” she said. “Stenting may provide a permanent solution.”
The crux of the debate on stenting is whether venous sinus stenosis is a cause or outcome of benign intracranial hypertension (BIH), said Dr. Felipe Albuquerque, an endovascular neurosurgeon at the Barrow Neurological Institute in Phoenix. The fact that 90% of affected patients have venous sinus stenosis on MRI suggests stenosis is a valid etiology the condition, he said.
But Dr. Friedman disagreed. In a retrospective study of 51 patients with BIH and transverse sinus stenosis, 71% had more than 50% stenosis, but the degree and location of stenosis did not predict clinical outcome. The analysis also found no link between cerebrospinal fluid pressure and the location, degree, or residual area of stenosis. Nonetheless, the procedure may be useful in patients who have persistent transverse sinus stenosis after undergoing a shunt procedure, she said.
The cons of stenting
“Stenting carries a high risk of morbidity and mortality, compared with currently used treatments, and should only be used as a last resort in patients who are losing vision,” Dr. Friedman asserted. Most patients do well, but others suffer serious complications, including life-threatening anaphylaxis, subdural hematomas, subarachnoid hemorrhage, and brain herniation, she said.
In contrast, optic nerve sheath fenestration for BIH has no associated fatalities, according to Dr. Friedman. And in a National Inpatient Sample database analysis of 1,224 shunts, mortality was only 0.9% for ventriculoperitoneal shunt and 0.3% for lumbar-peritoneal shunt. No deaths were recorded for shunts performed for BIH or pseudotumor cerebri, she added.
The literature on venous sinus stenting “is a mess,” Dr. Friedman continued. “All data are from retrospective case series, and the diagnosis of idiopathic intracranial hypertension is questionable in some cases,” she said. “The indication for stenting is not well defined.”
Studies on the safety and efficacy of stenting have lacked a common primary outcome variable and may reflect reporting bias, Dr. Friedman said. Studies have been heterogeneous with regard to disease duration and the presence or absence of papilledema, visual status, previous treatments, and definitions of treatment failure, she added. No randomized, controlled trials have been carried out with sham stenting to assess the possibility of placebo effect, she noted.
“I think stenting may have utility in patients who have failed conventional therapy and have had another procedure that did not work. I think it very likely that there is a strong placebo effect in this group,” Dr. Friedman said.
“It’s not like our existing procedures are wonderful,” she added. “I wish we had something better to offer our patients.”
Venous sinus stenting “is usually effective in ameliorating both subjective headache and objective papilledema symptoms,” Dr. Albuquerque said. “One could argue that both ventriculoperitoneal shunt and lumbar-peritoneal shunt, the most commonly performed surgical interventions for benign intracranial hypertension, are substantially more invasive than stenting is and associated with far more severe complications.”
Dr. Albuquerque described a prospective study he conducted with his associates on 15 patients with BIH who underwent venous sinus stenting. In all, 80% of patients said their headaches improved, and 60% reported at least a 50% decrease in headache pain. Rates of patency and technical success were 100%, and no patients had permanent complications from the procedure, although one patient developed acute retroperitoneal hematoma, he said.
Dr. Albuquerque also reported his long-term follow-up of 27 patients who underwent venous sinus stenting to treat pseudotumors. All patients had more than 50% stenosis confirmed by retrograde venogram and a transstenotic pressure gradient that was greater than 12 mm Hg. Fully 70% of patients improved symptomatically, but five underwent a shunt procedure after they failed to improve. Patients experienced no permanent complications, although one required a stent for femoral artery pseudoaneurysm. Angiographies performed an average of 23 months later showed that all stents remained patent, although four patients had mild (less than 25%) stenosis. Five patients had narrowing of the sinus proximal to the stent.