In the US, about one in 50 people live with an unruptured intracranial aneurysm on one of their cerebral arteries, often with no symptoms. Most of these blister-like lesions will never rupture, but when they do, it can be fatal. In fact, according to Cleveland Clinic, about 50% of patients who suffer a ruptured aneurysm will die from a subarachnoid haemorrhage or haemorrhagic stroke. Of those who survive, around 66% suffer permanent brain damage.

When an aneurysm ruptures, emergency treatment is required. Neurosurgeons typically use one of two techniques: neurosurgical clipping (open surgery) or endovascular coiling (a minimally invasive method). In the former, a surgical clip is inserted during craniotomy to isolate the aneurysm from normal circulation. In the latter, a coil is inserted via a catheter. The coil blocks blood flow to the aneurysm, preventing haemorrhage.

Clip or coil?

In 2017, the results of a randomised controlled trial comparing the long-term clinical outcomes and cost-effectiveness of the two methods was published by the London School of Hygiene & Tropical Medicine. Despite similar mortality rates in the first 90 days, fewer patients died in the mid-term (three months to three years) in the endovascular cohort than the open repair group (48% vs 56%). The endovascular group also spent less time in hospital and their treatment incurred lower costs.

The University of California San Diego (UC San Diego) describes the endovascular coiling method as the current standard of care for a ruptured aneurysm. But, despite the benefits, directing the medical device to the cerebral artery is incredibly difficult.

The blood vessels of the cerebral anatomy are among the most tortuous and fragile in the body. During the procedure, a curved-tip guidewire, inserted into an artery near the groin, takes a catheter up through the aorta and into the arteries of the brain. The guidewire is then removed and the coiled tip of the catheter is used to provide treatment. The whole procedure is done under fluoroscopy.

Precision components for complex procedures

Manufacturing the devices required for minimally invasive neurovascular surgeries such as intracranial aneurysm repair have introduced significant challenges for the medical device industry. According to UC San Diego, such instruments need to be smaller than one millimetre in diameter and about five feet long. These specifications have pushed the boundaries of traditional manufacturing techniques used for catheters and guidewires. Medical device makers, in partnership with their medical wire contract manufacturers, have stepped up to answer the needs of the sector with microcatheters and microguidewires.  

Custom Wire Technologies (CWT), a US-based contract manufacturer of custom-made medical wire components, has been a key partner along this journey. Throughout its 20 years in business, the company has built up a high level of expertise in the manufacture of micro-scale components for catheters and guidewires.

“Not all medical device companies can claim they have been producing micro coils since their inception,” says Jim Boldig, director of engineering at CWT. “When CWT was founded in 2002, one of the first machines purchased was a machine which specialised in producing micro coils.”

Everything produced at the CWT facility in Port Washington, Wisconsin is custom-designed to the specific requirements of medical device companies.

“There’s no project too small, but every project is important to the customer, and we like to treat each project as if it were our own. Ultimately, their success is hinged on that project succeeding,” says Boldig.

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