Failure of a Heifetz aneurysm clip

Area of Science:

• Materials Science
• Biomedical Engineering
• Pathology

Background:

• Aneurysm clips are critical medical devices used to secure and occlude blood vessels in the brain.
• The Heifetz aneurysm clip, manufactured from 17-7PH steel, has been utilized in neurosurgical procedures.

Observation:

• A 16-year-old female patient experienced an acute subarachnoid hemorrhage.
• The hemorrhage was directly linked to the fracture of a blade on a Heifetz aneurysm clip.
• Metallurgical analysis of the fractured clip revealed significant intergranular corrosion susceptibility in the 17-7PH steel.

Findings:

• The fracture mechanism was identified as stress corrosion.
• Stress corrosion resulted from the synergistic effects of mechanical stress, an electrolytic environment, and the inherent susceptibility of the 17-7PH steel to corrosion.
• The intergranular corrosion compromised the clip's structural integrity, leading to blade fracture.

Implications:

• This case highlights a critical failure mode in Heifetz aneurysm clips, emphasizing the importance of material selection and corrosion resistance in implantable medical devices.
• Findings underscore the need for rigorous material testing and quality control in the manufacturing of surgical implants to prevent catastrophic failures.
• The study contributes to understanding the long-term risks associated with specific metallic alloys in the physiological environment and informs future device design and material standards.