New surgical sensor could revolutionise brain surgery

18 Jan 2016

A new surgical implant could pave the way for a major progression in brain surgery, resulting in live monitoring of swelling achievable with minimal fuss. Extrapolated over other areas in the future, the discovery could also help drive organ monitoring.

A group of neurosurgeons and engineers in the US have devised a sensor that can be implanted relatively simply during brain surgery, monitoring swelling and allowing for immediate responses by doctors.

Should the sensor make its way into the current surgical landscape it will bring forward a process stuck in the 1980s, according to one Irish doctor who worked on the project.

A revolution

“Bioelectronics is going through a revolution at the moment,” explained Cork man Rory Murphy, a neurosurgery resident at the hospital as well as Washington University School of Medicine, which helped develop the product.

“We think our discovery is an exciting example of this,” he told me, with his team’s findings published in Nature.

Brain injuries are very commonly seen by Murphy and his colleagues in St Louis, with them working on projects like this every day.

The risk of swelling on the brain, though, is a constant reminder of how far we still have to go before neurosurgeons are truly happy with the tools on offer. In the US alone, for example, 50,000 people die from brain-pressure-related injuries every year.

Drilling down

“At the moment to test for swelling we drill a hole in patients’ heads and put in a small fibre optic cable which hooks up to a machine beside the bed,” explained Murphy. “It works very well but it’s 1980s technology.”

Murphy collaborated with engineers in the laboratory of John A. Rogers, a professor of materials science and engineering at the University of Illinois, to build new sensors.

The devices are made mainly of polylactic-co-glycolic acid and silicone, and they can transmit accurate pressure and temperature readings, as well as other information.

These sensors are about the size of a hypothermic needle, while they also dissolve after a period of time. That means they can be implanted during surgery, and then used afterwards to monitor patients’ subsequent recovery.

Advanced materials

“With advanced materials and device designs, we demonstrated that it is possible to create electronic implants that offer high performance and clinically relevant operation in hardware that completely resorbs into the body after the relevant functions are no longer needed,” Rogers explained.

“This type of bio-electric medicine has great potential in many areas of clinical care.”

It’s not ready for human patients yet, though. The team tested the sensors in saline solution first, which dissolved them in a few days. They then moved up to lab rats with Murphy, Rodgers and co hopeful that the subsequent successful results will put them in line for patient trials in the near future.

Small sensors, big results

“We’ve proven the concept. There are more federal hoops we need to get through. It’s still a good few years before this would be on the market,” said Murphy, who has another year or so finishing his neurosurgery training in the US before he returns to Ireland.

Sensors in medicine are becoming a big thing, with Irish involvement consistent throughout many discoveries. For example, late last year Tyndall and the NIBRT joined forced for PATsule, a project to developing a new kind of sensor for monitoring drug making.

Generally, sensors rest in a fixed position in bioreactors – which are the vessels that contain biological materials for bioprocessing the pharmaceuticals – and monitor material that they touch, giving good data to scientists with regard to the stage of the medicine production.

PATsule, though, will see sensors move freely throughout the bioreactor, providing a stream of data to monitor factors that might affect product yield or quality – the sensors are used solely for the production of protein therapies.

When all else fails

With regards neurosurgery, though, Murphy’s discovery could be huge. In patients with traumatic brain injuries, neurosurgeons attempt to decrease the pressure inside the skull using medications.

If pressure cannot be reduced sufficiently, patients often undergo surgery. The new devices could be placed into the brain at multiple locations during such operations.

“The ultimate strategy is to have a device that you can place in the brain — or in other organs in the body — that is entirely implanted, intimately connected with the organ you want to monitor and can transmit signals wirelessly,” explained Murphy.

That way it can provide information on the health of that organ, allowing doctors to intervene if necessary to prevent bigger problems.

“And then after the critical period that you actually want to monitor, it will dissolve away and disappear.”

Main image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic