History of endovascular surgery: personal accounts of the evolution.

Endovascular therapy has continuously evolved since it was first described in 1904. It was first used as a technique to inject particles to follow the flow into vascular lesions, and from the mid-seventies on, microballoons were developed to reach targets in the arterial vascular tree. Arteriovenous malformations were approached with catheters, the tip mounted by calibrated leak balloons. The embolizing material injected was cyanoacrylate labeled with Lipiodol (Lafayette Pharmacal, Lafayette, IN), a technique that is similar to what we use today. Flow-guided microballoons placed and detached in brain aneurysms eventually became unstable, making reperfusion and rupture possible. With the introduction of guidewire-supported microcatheters, controlled navigation in the endovascular tree became possible, allowing the injection of particles, liquid embolizing agents, or free coils. In 1991, detachable coils became available and brought new therapeutic concepts. Having learned that detachable coils could not be used to treat aneurysms, which were difficult to treat surgically, the neurosurgical community accepted this new technology primarily for patients in poor condition following aneurysmal subarachnoid hemorrhage. Increased experience led to better clinical results, and Guglielmi detachable coiling therapy began to be accepted also for patients with posterior circulation aneurysms. Recent controlled trials and new technologies improving the endovascular feasibility have raised the acceptance of endovascular therapy for brain aneurysms. The elegance of the endovascular approach was an important argument for this technology from its inception, but in early years, restricted endovascular efficacy limited the efficiency of embolizations. Increasing experience and exploding new technologies have made endovascular techniques not only safer but also as effective as microsurgery. The number of vascular pathologies where microsurgery is the only option is decreasing, and training in vascular neurosurgery may become the privilege of specialized centers in the future.