Minimally invasive electrical muscle stimulation corrects spinal curvature in children

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Adolescent idiopathic scoliosis affects 2–3% of children aged between 10 and 16. It is more common in girls than in boys (ratio of 10:1). Besides the obvious physical signs derived from the visible spinal deformity, the condition can cause psychological and emotional problems, such as low self-esteem and poor self-image body, that significantly reduces patients’ quality of life.

Although bracing has been used in non-surgical treatments for adolescent idiopathic scoliosis for almost fifty years, some studies suggest that this technique is able only to stop the curve progression, but cannot reduce the deformity. Furthermore, bracing often conditions or boosts psychological disorders in patients wearing the brace for a long period of time.

Patients developing high magnitude spinal curves or those who show a rapid and significant curve progression, often require a very aggressive surgery. More than 4,000 European adolescents undergo this procedure each year with the risk of long-term side effects.

“Surgery corrects the curve deformity, but fuses the spine, eliminating its function. The long term consequences of spinal fusion cause several complications,” says Carlos Barrios, director of the Institute for Research on Musculoskeletal Disorders of the Universidad Católica de Valencia, Spain, who has been twice awarded for his publications at EuroSpine Annual Meetings. “Efforts are currently being made to find techniques that do not involve extensive spinal fusion to correct the scoliotic deformity, preserving the physiological range of motion of the spine.”

Barrios continues, “A high proportion of diagnosed patients are normally subject to mere observation, without receiving specific therapy. However, if the disease is diagnosed late or develops faster than anticipated, current medical practice only has treatments with brace or surgery, each one with its drawbacks.”

Recent studies provide evidence that suggest possibilities for alternative treatments. “Recent findings show that adolescent idiopathic scoliosis is a musculoskeletal expression of a central nervous system disorder, in other words a neurological disease,” Barrios explains.

StimulAIS project

Neurological dysfunction affects deep paraspinal muscles inducing an imbalance of forces acting on the vertebral segments. The StimulAIS Project, supported by an international consortium of businesses, research institutes and universities, aims to introduce alternative scoliosis treatments based on electrical muscle stimulation of deep paraspinal rotator muscles—a technique known as functional electrical stimulation.

The consortium consists of three companies: the project coordinator Tequir SL (Spain), Synergie Ingeniere Medicale SARL (France) and Bentronic Gesellschaft Für Medizintechnik GMBH (Germany), working at three reference research centres: the Instituto de Biomecánica de Valencia (Spain), the Universidad Católica de Valencia (Spain) and Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung EV (Germany). Uniting their expertise, the project has developed the first prototypes of the device that provides the electrical stimulation treatment.

As a spokesperson of Tequir, a Spanish company that specialises in innovative medical technologies in the fields of spinal medicine, orthopaedics and traumatology, explains, “The unit should provide personalised treatments. It is primarily aimed at not only inhibiting the curve progression, but also potentially correcting it significantly.”

To achieve this, the project has developed an implantable device to sense and stimulate the key muscles as well as the integrated stimulation control software to modulate it into safety thresholds. To implement the device subcutaneously, the team has developed minimally invasive surgical instruments.

The findings obtained in the research phase have been incorporated into a stimulation protocol which allows real-time adaptation to the data received and therefore the treatments are more effective.

Barrios explains, “We have met the initial objectives and our proposal is significantly closer to commercialisation. The next aim of the consortium to continue the project is to produce a fully operational prototype in terms of greater efficiency-cost ratio. After reaching collaboration with specialised suppliers, this version of the product will take part in phase II and III clinical trials in order to validate the device.”

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