As the relationship between endovascular and open surgical approaches to cerebral aneurysm treatment continues to evolve, Edgar Samaniego (Iowa City, USA) discusses the appropriate place for both techniques moving forward.
Over the past decade, management of cerebral aneurysms has advanced rapidly. Endovascular therapy (EVT) has overtaken open surgical approaches in many centres because it is broadly applicable, less invasive, and increasingly effective. Key innovations include flow diversion for parent-artery remodelling, intrasaccular flow-diverter devices that simplify treatment of wide-neck bifurcation aneurysms while reducing coil burden, and a modern access armamentarium—guiding catheters, distal access catheters and microcatheters—that improves navigability to complex targets. As a result, lesions once considered the purview of microsurgery are now routinely treated endovascularly.
Microsurgical clipping remains important, especially for younger patients with favourable middle-cerebral anatomy, where standard approaches are well-tolerated and long-term durability is excellent. Optimal care occurs in high-volume centres that offer both microsurgery and EVT, with case selection made by a multidisciplinary team. This model is crucial for complex scenarios in which adjunctive strategies (e.g. bypass) may be required. Centres should meet a minimum annual aneurysm volume to maintain expertise; complex cases are best referred to programmes treating roughly ≥100 aneurysms per year,1 and outcomes appear better where at least ≥35 ruptured aneurysms per year are managed.2
Access and economics also shape practice patterns. In many low- and middle-income settings, the high cost of endovascular implants and imaging infrastructure sustains microsurgical clipping as the default therapy, and highly experienced surgeons achieve excellent outcomes, even for aneurysms that might otherwise be treated endovascularly. In the USA, the growth of neuroendovascular training across neurology, neurosurgery and radiology has expanded EVT availability. In Europe, EVT is predominantly delivered by neurosurgeons and neuroradiologists, with neurologists playing a more limited interventional role.
The trajectory in neurovascular care mirrors earlier shifts in cardiology: percutaneous interventions (e.g. coronary stenting) reduced the need for open bypass in many patients by offering safer, faster recovery with shorter hospital stays. Likewise, most endovascular aneurysm procedures require only overnight observation, and enable an earlier return to work compared with craniotomy and clip reconstruction.
As minimally invasive techniques continue to mature, the overall reliance on open surgery will likely diminish, but it should not disappear. Large tertiary cerebrovascular centres must preserve and cultivate microsurgical expertise, including extracranial-intracranial bypass, which remains essential for selected haemorrhagic lesions and steno-occlusive disorders such as moyamoya disease. Moreover, patients with aneurysmal subarachnoid haemorrhage should be triaged to comprehensive stroke centres capable of delivering the full spectrum of neurocritical care, EVT, microsurgery, and rescue therapies.
In conclusion, aneurysm treatment is steadily moving toward minimally invasive endovascular approaches, supported by ongoing device and imaging innovation. Microsurgical clipping remains crucial for selected anatomies, patient profiles and resource-limited environments. The highest standards of care arise when multidisciplinary, high-volume centres offer both modalities and tailor therapy to each patient’s age, anatomy, and comorbidities.
References:
- Etminan N, de Sousa D A, Tiseo C et al. European Stroke Organisation (ESO) guidelines on management of unruptured intracranial aneurysms. Eur Stroke J. 2022; 7(3): V.
- Leifer D, Fonarow G C, Hellkamp A et al. Association between hospital volumes and clinical outcomes for patients with nontraumatic subarachnoid hemorrhage. J Am Heart Assoc. 2021; 10(15): e018373.
Edgar Samaniego is a clinical professor of neurology, neurosurgery and radiology, and director of the Vascular Neurology Fellowship, at the University of Iowa in Iowa City, USA.
DISCLOSURES: The author declared no relevant disclosures.
