A raised bar for aneurysm surgery in the endovascular era

Key points:

  • To review advances in surgical treatment of aneurysms;
  • To highlight the importance of continued training in microsurgical techniques.

Despite microsurgical treatment of cerebral aneurysms has a documented history, the impressive progression of endovascular technology, techniques and skills, and the results of the International Subarachnoid Aneurysm Trial (ISAT) and the Barrow Ruptured Aneurysm Trial (BRAT) has altered the paradigm for treating intracranial aneurysms. These neurointerventional option have raised the bar for aneurysm surgery, in an era when most of the neurosurgery residents complete their training after having treated few brain aneurysms. In this paper, published online February 24, 2017 on Journal of Neurosurgery, Authors review advances in surgical treatment of aneurysms and highlight the importance of continued training in microsurgical techniques. Following useful neurosurgical tips and tricks:

Minimally Invasive Tailored Craniotomies
The aim of tailored craniotomy is to expose vascular lesions safely while minimizing morbidity to the adjacent brain. Experience has demonstrated shorter lengths of stay and improved subjective patient satisfaction with this technique compared with larger skull base approaches. This technique allows surgeons same control on aneurysm, proximal and distal parent artery, and perforators. Patient positioning is of paramount importance to obtain the optimal surgical corridor; tools like endoscope could be useful.

Retractorless Surgery
The aim of retractorless surgery or “dynamic retraction” is the use of the shaft of the suction and bipolar devices or microinstruments to mobilize the brain. The abandonment of fixed retractors avoids chronic pressure ischemia in the surrounding brain. It is important a complete understanding of the 3D anatomy of the case and skull base techniques (e.g., removal of the superior and lateral orbit, the clinoid, the zygoma, or the medial occipital condyle) create a working space that reduces the need for a fixed retractor.

Adjuncts for Aneurysm Exposure
Hydrodissection is an adjunctive tool to assist the opening of the sylvian and interhemispheric fissures. The use of hemostatics and fibrin sealants allows surgeons to control bleeding and minimize the use of cautery (especially in cavernous sinus aneurysms).

Circulation arrest
It is an important, but highly risky adjunct. The introduction of adenosine made this procedure much better tolerated, safer and more transient. Administration of adenosine could be necessary to decrease flow into the aneurysm, to have better control on proximal and distal parent artery and perforators.

Intraoperative Confirmation of Aneurysm Occlusion
The indocyanine green (ICG) angiography and Doppler ultrasonography allow the surgeon to document aneurysm occlusion, despite intraoperative DSA remain the gold standard; but its use is reduced due to surgical difficulties and the low diffusion of hybrid surgical rooms.

Revascularization Techniques for Difficult Aneurysms
Revascularization remains an essential tool for the most complicated aneurysms. Intracranial-to-intracranial bypass surgery or maxillary artery–to–middle cerebral artery bypass provide a shorter bypass length, avoid neck dissection or extensive drilling of the skull base. Furthermore, the addition of nonocclusive bypass techniques, such as ELANA, could be very useful.

In conclusion, the advent of novel tools and techniques are evolving the treatment of cerebral aneurysms and upcoming studies probably will change our perspectives; the application of progenitor cell or regenerative medicine approaches to assist the healing of injured vessels wall or the application of genome sequencing to identify biological pathways involved in endothelial cell damage are the future frontiers. But for now, are neurosurgery and interventional neuroradiology antagonists or they rapresent a single arsenal for the best treatment of patients?

Reference

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