Tag: spinal cord stimulation

Categories : Neurology Surgeries & ProceduresTags :

Spinal Surgeons can Now Monitor their Procedure’s Effects Mid-surgery

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Photo by Natanael Melchor on Unsplash

With technology developed at UC Riverside, scientists can, for the first time, make high resolution images of the human spinal cord during surgery. The advancement could help bring real relief to millions suffering chronic back pain.

The technology, known as fUSI or functional ultrasound imaging, not only enables clinicians to see the spinal cord, but also enables them to map the cord’s response to various treatments in real time. A paper published today in the journal Neuron details how fUSI worked for six people undergoing electrical stimulation for chronic back pain treatment.

“The fUSI scanner is freely mobile across various settings and eliminates the requirement for the extensive infrastructure associated with classical neuroimaging techniques, such as functional magnetic resonance imaging (fMRI),” said Vasileios Christopoulos, assistant professor of bioengineering at UCR who helped develop the technology. “Additionally, it offers ten times the sensitivity for detecting neuroactivation compared to fMRI.”

Until now, it has been difficult to evaluate whether a back pain treatment is working since patients are under general anaesthesia, unable provide verbal feedback on their pain levels during treatment. “With ultrasound, we can monitor blood flow changes in the spinal cord induced by the electrical stimulation. This can be an indication that the treatment is working,” Christopoulos said.

The spinal cord is an “unfriendly area” for traditional imaging techniques due to significant motion artifacts, such as heart pulsation and breathing. “These movements introduce unwanted noise into the signal, making the spinal cord an unfavorable target for traditional neuroimaging techniques,” Christopoulos said.

By contrast, fUSI is less sensitive to motion artifacts, using echoes from red blood cells in the area of interest to generate a clear image. “It’s like submarine sonar, which uses sound to navigate and detect objects underwater,” Christopoulos said. “Based on the strength and speed of the echo, they can learn a lot about the objects nearby.”

Christopoulos partnered with the USC Neurorestoration Center at Keck Hospital to test the technology on six patients with chronic low back pain. These patients were already scheduled for the last-ditch pain surgery, as no other treatments, including drugs, had helped to ease their suffering. For this surgery, clinicians stimulated the spinal cord with electrodes, in the hopes that the voltage would alleviate the patient’s discomfort and improve their quality of life.

“If you bump your hand, instinctively, you rub it. Rubbing increases blood flow, stimulates sensory nerves, and sends a signal to your brain that masks the pain,” Christopoulos said. “We believe spinal cord stimulation may work the same way, but we needed a way to view the activation of the spinal cord induced by the stimulation.”

The Neuron paper details how fUSI can detect blood flow changes at unprecedented levels of less than 1mm/s. For comparison, fMRI is only able to detect changes of 2cm/s.

“We have big arteries and smaller branches, the capillaries. They are extremely thin, penetrating your brain and spinal cord, and bringing oxygen places so they can survive,” Christopoulos said. “With fUSI, we can measure these tiny but critical changes in blood flow.”

Generally, this type of surgery has a 50% success rate, which Christopoulos hopes will be dramatically increased with improved monitoring of the blood flow changes. “We needed to know how fast the blood is flowing, how strong, and how long it takes for blood flow to get back to baseline after spinal stimulation. Now, we will have these answers,” Christopoulos said.

Moving forward, the researchers are also hoping to show that fUSI can help optimise treatments for patients who have lost bladder control due to spinal cord injury or age. “We may be able to modulate the spinal cord neurons to improve bladder control,” Christopoulos said.

“With less risk of damage than older methods, fUSI will enable more effective pain treatments that are optimised for individual patients,” Christopoulos said. “It is a very exciting development.”

Source: University of California Riverside

Categories : Implants and Prostheses NeurologyTags : 2 Comments

‘Digital Bridging’ Enables Paraplegic Man to Walk Again

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Study participant Gert-Jan Oskam walking with the brain-spine interface. Credit: Swiss Federal Institute of Technology in Lausanne

A 40 year-old man, Gert-Jan Oskam, has regained the ability to walk independently after being paralysed from a spinal cord injury with the use of a new brain-spine interface. The ‘digital bridging’ technology, developed at the Swiss Federal Institute of Technology in Lausanne and described in Nature, consists of implants and a computer to translate brain signals of the intention to move into stimulations that move the legs accordingly..

This BSI system could be calibrated in minutes, and remained stable for one year, including use at home. The BSI enabled the participant to exert natural control over the movements of his legs to stand, walk, climb stairs and even traverse complex terrains.

In addition to the digital bridging, neurorehabilitation supported by the BSI improved neurological recovery. The participant regained the ability to walk with crutches overground even when the BSI was switched off. This digital bridge establishes a framework to restore natural control of movement after paralysis.

The system consists of a pair cortical of sensors, each an array with 64 electrodes housed in 5cm-diameter titanium discs. These discs are implanted snugly in the skull to pick up brain activity. They transmit the data wirelessly to a personalised headset, which also provides power for the sensors. The headset then sends the data to a portable processing unit (which may be carried in a backpack). Using specialised software, it uses this brain signal data to generates real-time predictions of motor intentions. These decoded intentions are translated into stimulation commands and sent on to another implant, a paddle array of 16 electrodes implanted next to the spinal cord, delivering current to the targeted dorsal root entry zones.

Neurosurgical implantation procedure

Oskam had sustained an incomplete cervical (C5/C6) spinal cord injury during a biking accident 10 years previously. He had already participated in a neurological recovery programme, the STIMO trial, which had used neurostimulation to get him to the stage where he could walk with the aid of a front-wheel walker. The neurorehabilitation from the trial also enabled him to use his hip flexors and lift his legs against gravity, but recovery had plateaued for the three years prior to his participation in the present study.

For the BSI to function, the researchers needed to locate neural features related to the intention to move the legs. To pinpoint the cortical regions associated with the intention to move, they used CT scans and magnetoencephalography. Taking into account anatomical restraints, they then decided on the positions of the implants.

Under general anaesthesia, surgeons performed a bicoronal incision of the scalp to allow two circular-shaped craniotomies over the planned locations of the left and right hemispheres. They then replaced the bone flaps with the two implantable recording devices, before closing the scalp.

The paddle lead had already been emplaced over the dorsal root entry zones of the lumbar spinal cord during the STIMO clinical trial. Its optimal positioning was identified using high-resolution structural imaging of the spine, and its final position was decided during the surgery based on electrophysiological recordings. The implantable pulse generator was inserted subcutaneously in the abdomen. Oskam was able to return home 24 hours after each procedure.

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New Review Finds Spinal Cord Stimulation Ineffective for Low Back Pain

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Photo by Sasun Bughdaryan on Unsplash

Spinal cord stimulation for the treatment of chronic pain does not provide long-term relief and may cause harm, according to a new Cochrane Review. Spinal cord stimulation involves an implanted device that sends electrical pulses to the spinal cord to interrupt nerve signals before they get to the brain.

The study reviewed published clinical data on spinal cord stimulation, including randomised controlled trials, the ‘gold standard’ for medical research. The researchers analysed the results of 13 clinical trials, looking at data from 699 participants, comparing spinal cord stimulation treatment with placebo or no treatment for low back pain.

Cochrane reviews are trusted by researchers, medical professionals and policymakers because they use robust methodologies to combine evidence from multiple sources, reducing the impact of bias and random error that can make individual studies less reliable.

The review concluded that spinal cord stimulation is no better than a placebo for treating low back pain, with probably little to no benefit for people with low back pain or improvement in their quality of life.

There was little to no clinical data regarding the long-term effectiveness of spinal cord stimulation.

The researchers also found that adverse side effects to the surgery were poorly documented overall, preventing them from concluding the level of risk involved. Harms from spinal cord stimulation could include nerve damage, infection, and the electrical leads moving, all of which may need repeated surgeries.

The review findings have been submitted to the Federal Department of Health and Aged Care prosthesis list review taskforce. The taskforce is reviewing the eligibility of current prostheses subsidised by Medicare.

In Australia, the devices’ long-term safety and performance are also being re-assessed by The Therapeutic Goods Administration (TGA), the country’s regulatory authority for therapeutic goods.

“Spinal cord stimulation is invasive and has a great financial cost to people who choose surgery as a last resort to alleviate their pain. Our review found that the long-term benefits and harms are essentially unknown,” said lead researcher Dr Adrian Traeger from Sydney Musculoskeletal Health, an initiative of the University of Sydney, Sydney Local Health District and Northern Sydney Local Health District.

“Our review of the clinical data suggests no sustained benefits to the surgery outweigh the costs and risks.

“Low back pain is one of the leading causes of disability worldwide. Our findings further emphasise the urgent need to review funding arrangements for chronic pain care to help patients in their search for relief. There are evidence-based physical and psychological therapies for back pain; ensuring access to these is essential.”

The review team found multiple gaps in clinical data.

There were no studies that investigated the long-term (more than 12 months) impact of spinal cord stimulation on low back pain. The longest was a single six-month trial.

The majority of clinical trials only looked at the immediate impact of the device, which is a time frame of less than a month.

The review team provided a list of recommendations, including that future spinal cord stimulation clinical trials be at least 12 months, clearly document the number of people who experience adverse events and make comparisons with other pain treatment options.

Professor Chris Maher,Co-Director of Sydney Musculoskeletal Health, said:

“Our review found that the clinical benefit of adding spinal cord stimulation to treat low back pain remains unknown. When coupled with the reality that these devices are very expensive and often break down there is clearly a problem here that should be of concern to regulators.”

A separate Cochrane review, in which the researchers were not involved, examined the effect of spinal cord stimulation versus placebo in people with chronic pain. Similar to this review, it concluded there was a lack of evidence to suggest long-term benefits in treating chronic pain.

Source: University of Sydney