Exoskeletons in medicine: what they do and where they are used

They still seem futuristic, but have long since made their way from research into everyday (clinical) practice: exoskeletons. An exoskeleton supports and relieves the human body during movement. In medicine, the technology has already opened new possibilities in rehabilitation. Other areas such as surgery and nursing are now following suit.

The following article provides an overview of exoskeletons and their use in medicine. It is the first part of our series on exoskeletons in medicine.

An exoskeleton is an external, wearable structure that supports or relieves the human body during movement. It is a mechanical construction that is worn on the body and amplifies or guides movements.

Exoskeletons can be roughly divided into two categories:

• An active exoskeleton uses motors and sensors to support movement. This can be achieved using mechanical, electrical, or pneumatic components.
• A passive exoskeleton works without an energy supply, but specifically relieves the body during sustained activities, for example through springs, cable pulls, or mechanical levers.

An exoskeleton should not be equated with a prosthesis: a prosthesis replaces lost limbs, while an exoskeleton supplements or stabilizes the existing musculoskeletal system. This means that exoskeletons are closer to classic orthoses.

An exoskeleton works with joints, sensors, and, if necessary, drive systems that are worn on the body (extremities, back, torso, neck, or spine) to varying degrees. Integrated sensors detect movement intentions or body postures. In an active exoskeleton, signals are transmitted to actuators that support joint movements. In this way, an exoskeleton amplifies the natural movements of the person wearing it. Ideally, this is done without restricting the wearer's own mobility to maximize the benefits in professional use.

Important functional principles of an exoskeleton are:

• Sensors: detect muscle activity, movement, or posture
• Actuators: guide or amplify movements
• Control systems: process signals in real time
• Ergonomic structure: distributes weight, enables mobility and wearing comfort even over long periods of time

Exoskeletons have several applications in medicine. They benefit both patients and medical staff.

• Rehabilitation: Patients who have suffered a stroke, spinal cord injury, or live with MS use exoskeletons to train specific movement sequences. The exoskeleton promotes neural reorganization through repeated movement.
• Orthopedic therapy: Devices with exoskeleton-like functions stabilize joints or enable assisted walking in cases of muscle weakness, like classic orthoses.
• Care: Exoskeletons for caregivers reduce physical strain during activities such as lifting or repositioning patients. The risk of work-related ailments is reduced using an exoskeleton.
• Surgery: Exoskeletons for doctors are used during long surgical procedures. An exoskeleton stabilizes posture for hours, prevents fatigue and improves precision.