A Portrait of the Brain

A Portrait of the Brain Author: Adam Zeman Synopsis How do you sketch a vivid profile of the most perplexing organ in the body? How do you portray the intricate workings of what is, ‘by a very long way, the most complex entity we have yet encountered in the universe‘? (page 36). The author of […]

via A Portrait of the Brain — The Doctors Bookshelf

Clipping the wings of cerebral aneurysms: is the pendulum swinging back?

This is a follow up to my previous blog post, What should we really know about cerebral aneurysms? In that post, I discussed the nature and presentations of cerebral aneurysms. In this post I will look at the two major treatments for cerebral aneurysms, exploring their pros and cons, and looking at some emerging challenges to the conventional wisdom. 

By Tiago Etiene QueirozOwn work, CC BY-SA 3.0, Link

The first question to answer regarding treatment of aneurysms is whether they need any treatment at all. In other words, are they best left well alone? In principle, aneurysms that have ruptured require treatment, irrespective of their size. On the other hand, aneurysms that are discovered incidentally, before they rupture, may not need surgical treatment unless they are large (usually 7mm or more in diameter), or they are associated with high-risk features/locations. Low-risk aneurysms that do not require treatment however need long-term surveillance with intermittent brain imaging. To limit the growth of such aneurysms, people harbouring them are advised to stop smoking, and if they have hypertension, to ensure that this is well-controlled.

By Professor Dr. O. Bollinger. – LEHMANN’S MEDICIN. HAND ATLANTEN Atlas und Grundrissder PATHOLOGISCHENANATOMIE 1901, Public Domain, Link

There are two treatment approaches to ruptured aneurysms and high-risk unruptured aneurysms. The first is invasive and neurosurgical; the cranium is opened, the aneurysm located, and a surgical clip is put around its neck, sequestering it from its parent vessel. In this way, with its wing literally clipped, the aneurysm is disarmed, its potential for growth and rupture severely restricted. 

By Roberto Stefini – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47226273

The other procedure, younger and safer than clipping, is endovascular coiling or coil embolisation. This procedure, performed by an interventional neuroradiologist, involves tunnelling a fine wire or coil through blood vessels until it reaches the aneurysm. The aneurysm space is then filled up with the coil until it is totally obliterated. Unable to fill up with blood or expand, the aneurysm is rendered impotent. Both coiling and clipping however carry a small failure risk, resulting in aneurysm recurrence or re-rupture.

By 77giallo77 – Own work, CC BY-SA 4.0, Link

This is the conventional wisdom of cerebral aneurysm treatment. But there are advocates out there who are pushing the case for clipping over coiling. One reason they put forward is the emerging observation that clipping results in better recovery of function of the third cranial or oculomotor nerve. The oculomotor nerve is critical to the movement of the eye and eyelid, and it is vulnerable to compression by the posterior communicating artery (PCOM) aneurysm. A compressed third cranial nerve results in a droopy eyelid (ptosis) and double vision (diplopia); recovery of function of the oculomotor nerve is therefore an important goal in the treatment of aneurysms.

Автор: Patrick J. Lynch, medical illustrator – Patrick J. Lynch, medical illustrator, CC BY 2.5, Посилання

There are now at least four systematic reviews and/or meta-analyses that show that recovery of the oculomotor nerve function is better achieved by clipping than by coiling. These are:

Another meta-analysis, titled Clinical outcome after surgical clipping or endovascular coiling for cerebral aneurysms, goes further to argue that clipping results in better chances of survival and independent living than coiling. 

By HellerhoffOwn work, CC BY-SA 3.0, Link

These may be the last-gasp attempts of clippers to have one up over coilers, but the consensus still remains dominantly in favour of endovascular coiling. We however need to keep a close eye on this pendulum-it may just swing back unexpectedly.

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Why not check out these related blog posts:

How does aspirin influence the rupture risk of cerebral aneurysms?

Is the growth of cerebral aneurysms predictable?

Reaching Down the Rabbit Hole 

Reaching Down the Rabbit Hole Authors: Allan H. Ropper and Brian David Burrell Synopsis This book is about the day-to-day practice of one of the leading neurologists in the world. It explores his challenging work in one of the most prestigious of hospitals, the Brigham and Women’s Hospital– ‘a place where the strangest and challenging […]

via Reaching Down the Rabbit Hole  — The Doctors Bookshelf