What Is Aneurysm Surgery?

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An aneurysm is a dilation or bulge of an artery by at least 50% more than the original width of the vessel.1,2 They occur in different arteries in the body and can be classified according to their site. Treatment will depend on where and how big they are. The concern with aneurysms is that they can potentially rupture. This is when the vessel wall breaks, resulting in blood within the blood vessel spilling out. This can be catastrophic, even leading to death depending on the site of the aneurysm.1 

This article will cover what aneurysms are, the risk factors that can cause them and ways to reduce your risk of developing them.

Anatomy of the artery

There are three layers to an artery wall from inner to outer;2 

  • The intima
  • The media 
  • The adventitia

The intima layer has endothelial cells which are important in regulating aspects of the vessel size and also proteins that prevent blood clotting within the blood vessel. 

The middle layer, the media, is composed of smooth muscle cells and plays an important role in the structure, strength and elasticity of the vessel wall.2 

The outer adventitia layer contains collagen and inflammatory response cells. Fat tissue surrounds this outer layer.2

Changes at each of the three layers including breakdown of structural support, inflammation and changes of vascular smooth muscle affect the stability of the vessel walls leading to weakness. This weakness can cause the vessel wall to bulge out, leading to the formation of an aneurysm.3

Risk factors and causes 

The causes of aneurysms can be a mixture of genetic, molecular and biomechanical (blood flow causing changes to the vessel wall) and inflammatory changes. These cause the structure of the vessel wall to change over time which can lead to an aneurysm forming.2 

Sometimes an aneurysm can be due to an underlying disease or cause. For example, trauma, infections, inflammatory causes and connective tissue disorders such as Marfan's syndrome can cause aneurysms to form.4  Infections can cause inflammation in the artery wall where there is a breakdown in the elastic fibres leading to dilation and aneurysm 4. Atherosclerosis, a condition that causes blood vessels to narrow due to build-ups of fatty plaques, is associated with aneurysm formation.4 Smoking and high blood pressure are also known risk factors for aneurysms.4,5

Genetics also plays a role in developing an aneurysm. This can be seen in cerebral aneurysms where baseline risk in the general population is 2.3% increasing to 4% in those with a first-degree relative (parent, sibling or child) that has had or has a cerebral aneurysm.5 Autosomal dominant polycystic kidney disease, a type of inherited cystic kidney condition is the most common genetic condition linked with cerebral aneurysms.5 Those assigned male at birth also have an increased chance of developing an aneurysm so screening is offered when they turn 65 years old in many countries.6

Types of aneurysms

These can be classified according to where they’re located within the body. If an aneurysm forms within the brain, they are called a cerebral aneurysm. The large blood vessel that carries blood from the heart is called the aorta and aneurysms can occur along this vessel  - either within the thorax (chest area) called thoracic aneurysm or as the aorta passes through the abdomen - an abdominal aortic aneurysm (AAA).4


Aneurysms can be diagnosed via screening with ultrasound which gives an accurate diagnosis at almost 100%.4 Computerised Tomography (CT) and Magnetic Resonance Imaging (MRI) scans with a specific type of X-ray that looks at blood vessels (angiography) are used to locate potential aneurysms and determine their size. From here, healthcare professionals can plan any potential surgery.4 

Cerebral aneurysm

These occur in up to 3-5% of the general population.5,7 Most of them go unnoticed and are never located.7  Cerebral aneurysms are formed commonly via a mixture of genetic, changes in blood flow and inflammatory processes.5 The most concerning aspect of cerebral aneurysms is that if they rupture, it results in a haemorrhagic stroke.5  

How do cerebral aneurysms present? 

Subarachnoid haemorrhage - a type of serious bleeding in the brain from a cerebral aneurysm is the most common way cerebral aneurysms are detected.7 These can present with what is termed a ‘thunderclap headache’ which is a very severe headache, as well as other symptoms such as a stiff neck, vomiting and difficulty looking at light.8

Aortic aneurysms

Aortic aneurysms can happen in any part of the aorta - ascending or descending as the aorta comes out from the heart in the chest, (thoracic aortic aneurysm) and in the abdomen, - abdominal aortic aneurysm often known as AAA.4

Generally, aortic aneurysms are asymptomatic, however, if they rupture, they can be very dangerous, accounting for roughly 200,000 deaths per year worldwide.4 Mortality from a AAA rupture is ~80%.4 Those with a width of less than 4 cm have a negligible chance of rupture.6

Treatment of aneurysms 

When an aneurysm has been found, a decision is made on how to treat it depending on factors including site and likelihood of rupture.8

Pre-operative assessment 

Healthcare professionals will discuss with you the types of surgery and which would be best to treat your specific aneurysm. This discussion will also include a pre-assessment covering things such as any other health conditions you have and any medication you are taking. Some medications may be okay to continue taking while some need to continue or stop will be discussed. 

Cerebral aneurysms

Surgical procedures for cerebral aneurysms include:

Surgical clipping

This involves going under general anaesthetic before a section of the skull is removed. The aneurysm is then located and a clip is placed at the neck of the aneurysm.9

Endovascular coiling

Access to the artery of interest is gained via inserting a tube into the artery in the groin to access the arteries in the brain. Here coils are released into the aneurysm until no contrast is seen filling the aneurysm during imaging captured during the procedure.7

Aortic aneurysms

Repair surgeries can include both open and endovascular (surgery on blood vessels that is minimally invasive and doesn’t require being cut open) but depend on where the aneurysm is and it’s size.

Open graft repair surgery

AAAs can be repaired with a synthetic graft. This involves opening the abdomen to access the abdominal aorta, removing the segment of the blood vessel wall causing the aneurysm and placing a synthetic tube graft around the remaining blood vessel wall. 6

Endovascular Stent - TEVAR and EVAR (Thoracic) endovascular aortic aneurysm repair

EVAR surgery involves placing a stent into the aneurysmal part of the vessel of the artery. A needle is inserted into the groin area to reach one of the femoral arteries. A thin tube is then passed through the hole made by the needle and into the femoral artery. Within this thin tube is the stent. The thin tube is then guided to where the aneurysm is before being deployed. When deployed, the stent opens up within the blood vessel, creating a stable tube which blood can flow through, without coming into contact with the aneurysm section. Once deployed, the thin tube is removed and the entry hole closes without needing stitches.6

Post-surgery treatment

Post-operative management will depend on the patient and the outcome of the operation. There will be a surgical team of doctors and nurses, in addition to the rehabilitation team of physiotherapists and occupational therapists who will help get the patient back on their feet. 

The length of stay in the hospital will depend on what type of surgery is being done and if there are any other medical conditions. Typically, hospital stays for cerebral aneurysm surgery are longer at around 14 days on average. Aortic aneurysm surgeries usually have shorter hospital stays, on average, less than 7 days.10,11

The time required to recover to presurgery functioning has a median of 3 months, however, cerebral aneurysm surgery usually takes more time to recover compared to aortic aneurysm surgery. It should be noted that there is also the chance that you may never fully recover after aneurysm surgery with those who don’t commonly suffer from tiredness, memory problems and concentration problems. However, the likelihood of not fully recovering is linked to in-hospital complications and the size of the aneurysm.11

The median time before returning to work for people who have had aneurysm surgery is also 3 months. Similar to presurgery functioning, those who have surgery for cerebral aneurysms take longer before returning to work compared to those who have aortic aneurysms.11


Aneurysms are dilations or bulges of an artery by at least 50% more than the original width of the vessel. They are dangerous due to the risk of them rupturing, causing internal bleeding. Surgery techniques for aneurysms depend on their location. For cerebral aneurysms, surgical techniques include surgical clipping and Endovascular coiling. For Aortic aneurysms, endovascular aortic aneurysm repair surgery is required which involves placing a stint into the aneurysm. The recovery time required after surgery depends on the type of aneurysm, the type of surgery as well as the size aneurysm itself.


  1. Setty HSN, P RM, Patil R, Patil SS, Kumar JRV, Manjunath CN. Aneurysms: a comprehensive review. JSM Atherosclerosis [Internet]. 2017 Jan 4; Available from: https://www.jscimedcentral.com/article/Aneurysms%3A-A-Comprehensive--Review
  2. Costa D, Andreucci M, Ielapi N, Serraino GF, Mastroroberto P, Bracale UM, et al. Vascular biology of arterial aneurysms. Annals of Vascular Surgery [Internet]. 2023 Aug 1 [cited 2023 Dec 15];94:378–89. Available from: https://www.sciencedirect.com/science/article/pii/S089050962300225X
  3. Cho MJ, Lee MR, Park JG. Aortic aneurysms: current pathogenesis and therapeutic targets. Exp Mol Med [Internet]. 2023 Dec 1 [cited 2023 Dec 15];1–12. Available from: https://www.nature.com/articles/s12276-023-01130-w
  4. Gao J, Cao H, Hu G, Wu Y, Xu Y, Cui H, et al. The mechanism and therapy of aortic aneurysms. Sig Transduct Target Ther [Internet]. 2023 Feb 3 [cited 2023 Dec 15];8(1):1–20. Available from: https://www.nature.com/articles/s41392-023-01325-7
  5. Chalouhi N, Hoh BL, Hasan D. Review of cerebral aneurysm formation, growth, and rupture. Stroke [Internet]. 2013 Dec [cited 2023 Dec 15];44(12):3613–22. Available from: https://www.ahajournals.org/doi/10.1161/STROKEAHA.113.002390
  6. Swerdlow NJ, Wu WW, Schermerhorn ML. Open and endovascular management of aortic aneurysms. Circ Res [Internet]. 2019 Feb 15 [cited 2023 Dec 15];124(4):647–61. Available from: https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.118.313186
  7. Seibert B, Tummala RP, Chow R, Faridar A, Mousavi SA, Divani AA. Intracranial aneurysms: review of current treatment options and outcomes. Front Neurol [Internet]. 2011 Jul 8 [cited 2023 Dec 15];2:45. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3134887/
  8. NHS.UK [Internet]. NHS; 2022. Overview Brain Aneurysm. Available from: https://www.nhs.uk/conditions/brain-aneurysm/
  9. Belavadi R, Gudigopuram SVR, Raguthu CC, Gajjela H, Kela I, Kakarala CL, et al. Surgical clipping versus endovascular coiling in the management of intracranial aneurysms. Cureus [Internet]. 13(12):e20478. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8760002/
  10. Sarmento RM, Rosa RDS. Hospital admissions for treatment of ruptured and unruptured cerebral aneurysms within the Brazilian National Health System, 2009-2018: a descriptive study. Epidemiol Serv Saude. 2022;31(2):e20211122.
  11. Backes D, Rinkel GJE, Van Der Schaaf IC, Nij Bijvank JA, Verweij BH, Visser-Meily JMA, et al. Recovery to preinterventional functioning, return-to-work, and life satisfaction after treatment of unruptured aneurysms. Stroke [Internet]. 2015 Jun [cited 2024 May 26];46(6):1607–12. Available from: https://www.ahajournals.org/doi/10.1161/STROKEAHA.115.008795

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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