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  • Writer's pictureIna Vogt

A Step Towards the Future: Lea's Hybrid Manufactured Lower Limb Carbon Orthosis

From a Wheelchair to an Orthosis - How a Young Woman Fought Her Way Back to an Active Life

It has been almost four years since the accident that turned Lea's world upside down. A single day changed everything and set Lea on a journey to find an assistive device that would make her life worth living again. It became clear to her early on that day the wheelchair could only be an intermediate step on this path. She wanted to take the decisive steps herself. And now, she can do so with a perfectly fitting hybrid manufactured lower limb orthosis - an orthosis that is partially created using digital processes. In this blog post, we will share the story of how it all came together.

Lea's positive attitude never wavered throughout this entire time.
Lea's positive attitude never wavered throughout this entire time. (Source: Rohde)

Lea, who is just 18 years old and in the midst of her vocational training as an operating room assistant, had her life profoundly changed by a work accident in the summer of 2019. She had an unfortunate fall that resulted in serious injuries. When she woke up in the intensive care unit, she could no longer walk and had lost sensation in her legs. She couldn't dress herself, needed help with eating, and overnight became dependent on care.

During that challenging period, Lea often found herself pondering, "Why me? Why now?" "My body was covered in scars on my legs, back, and abdomen. My lung capacity was limited. I could only speak or even laugh softly. It felt like someone was standing on my chest." This is how Lea described her condition at the time. Amid the visual scars and physical adversity, Lea never stopped fighting, even when it became clear that her leg muscles would remain permanently paralyzed. With the support of her friends, family, and the orthopedic lab, Lea made significant strides in her recovery and now ambulates with a hybrid manufactured lower limb orthosis.

Diagnosis: "Rare Disease"

When simple activities like walking or grasping objects become impossible because the leg or arm no longer cooperates, it indicates paralysis, a condition known as "paresthesia". Lea, since her accident, has been affected by a condition called "paraparesis," which is a partial paralysis of two parallel limbs (usually both legs). This type of muscle paralysis occurs as a secondary condition, for example, as a result of a stroke or damage to a motor nerve in the central nervous system. (Source) Due to her paraparesis, Lea experiences significant balance and coordination problems. The lack of stability in her knees poses an increased risk of falling. Since her accident, she has relied on assistive devices. A wheelchair became her constant companion.

In addition, Lea suffers from a complex regional pain syndrome (CRPS), which is a chronic neuropathic pain that lasts longer and is more intense than expected after the initial tissue injury. In Lea's case, it is also a consequence of the nerve damage caused by the accident. (Source) Lea is one of an estimated four million people in Germany who suffer from a rare disease (Source). As is often the case with CRPS, the disease is chronic for Lea and entails significant limitations in everyday life and the quality of life.

May 2022: Lea in her wheel chair.
May 2022: Lea in her wheel chair (Source: Instagram)

A Moment of Success Thanks to a Swiss Study

Then, at the end of 2021, a glimmer of hope emerged: Her treating neurologist and a neurosurgeon approached her and informed her about a Swiss study in which she would participate. Two surgeries were on the horizon. In the first surgery, an electrode array would be attached to the spinal cord in the damaged segment and be connected to an external pulse generator on the side of the ribs. After a successful testing phase, the second surgery would involve implanting the pulse generator and routing the cables under the skin. "The cyborg was created! 😅🤖" Lea jokingly commented in a post on her Instagram channel.

Following an intensive rehabilitation phase, the first successes emerged: Her nerve pain was reduced by over 50%, and she regained sensitivity in her thighs. "The limitations after the surgeries are not without their challenges. It takes several months for the bones, muscles, scars, and nervous system to adjust. BUT it has paid off and given me back a piece of quality of life," writes Lea.

It's Time to Learn to Walk

Then, in the summer of 2022, another ray of hope emerged: Three years after her accident, through hard training and with the help of modern technology, Lea could finally stand again—on both legs. On one side, she is equipped with a C-Brace from Ottobock, and on the other side, she wears a different lower limb orthosis. The C-Brace, an "electronic leg" on the weaker right side, enables her to walk, climb stairs, and navigate slight inclines. She receives the necessary support on the other side in the form of an AFO. "A new era is beginning for me!" exclaims Lea, who knows exactly how many days have passed since her accident.

Forging Ahead: The Clinician’s Unwavering Quest for Innovation

Initially, Lea was equipped with a composite AFO on her left lower leg, but unfortunately, it failed to provide her with the necessary support and security. Recognizing the need for a tailored solution, Clinician and Orthopedic technician Aaron Wassermann took on the challenge of developing an ankle-foot orthosis. To complete the task, Aaron relied on a combining of both digital and manual steps in the manufacturing process, which had demonstrated its effectiveness with previous patients.

Aaron Wassermann from medical supply house Rohde is Lea's clinician & orthopedic technician.
Aaron Wassermann from medical supply house Rohde is Lea's clinician & orthopedic technician. (Source: Rohde)

Aaron completed his training as an orthopedic technician at Rohde in August 2022. He already has about ten digital fittings under his belt and is convinced of their advantages. For him, it is clear that a successful fitting must be optimally tailored to each individual patient. He has found that the benefits of digital work outweigh traditional methods, especially during the correction and modeling phases. By working digitally, he can make fine adjustments more quickly, compare different results, and modify process steps if needed. In short, he can tinker on the computer until he achieves the best possible result and is satisfied.

Unofficially, Aaron serves as the "Digitalization Officer" at Rohde – his role is to eliminate uncertainties, examine new technologies, and share the results with the team. Overall, the orthopedic lab is well on its way to a digital future. Currently, orthotic fittings are partially developed using a digital workflow, meaning that part of the orthosis is created using traditional methods, while the other part is produced digitally. Currently, 20-30% of orthotics fittings are utilizing scanning to 3D-print splints. This upward trend signifies a growing adoption of digital technologies in orthotics manufacturing.

Aaron's plan for Lea's orthosis: He intends to perform the correction of the joint angles and to modify the positive model digitally, have the positive model manufactured externally, and finally build the orthosis using the prepreg process. Aaron has witnessed numerous advantages by incorporating a digital workflow into his practice, including "reduced fabrication time, a cleaner working environment, and improved workspace cleanliness."

Lea is a paraparesis patient, with bilateral limb paralysis.
Lea is a paraparesis patient, with bilateral limb paralysis. (Source: Rohde)

The Hybrid Solution: From a Scan to a Finished Carbon Orthosis

To achieve the desired goal, Lea's leg is first scanned. The scanning process is not only faster for the clinician but also much more comfortable for the patient. "The manufacturing of the orthosis was associated with significantly less effort for me. There were no major "plaster disasters” as before. Taking the plaster cast on the right leg was a major challenge due to the paralysis. It was very heavy, requiring several people to hold the leg during the casting process. Moreover, as a customer, casting with plaster requires significant physical exertion. The scan was super quick and without any problems," confirms Lea.

The subsequent correction and functional form modeling using Mecuris’ software were done digitally within an hour. For the correction, including dorsiflexion, pronation, supination, and forefoot adjustment, Aaron needed ten minutes, allowing him to compare the digital model with the original scan in between. In the subsequent 50-minute functional form modeling, the digitally aligned model, adjusted for posture, was smoothed out to remove irregularities such as corners and edges.

Afterwards, using the Apply tool, material was added in the ankle area, and the Merge tool was used to attach a forefoot extension. The surrounding areas were smoothed, and a four-millimeter offset was created to accommodate future padding. The "global smoothing" function ensured uniformly smooth transitions overall. The final step involved setting the joint/axis of rotation ("tango joint") and downloading the finished .stl file.

The digital positive model of Lea's leg.
The digital positive model of Lea's leg.

Hybrid approach: From the 3D Printer to the Oven

Next, the digital file was sent to Cure-Lab, a German-based company specializing in 3D printing for orthopedic technology. They 3D printed Lea's modeled leg using the FDM process in approximately 17 hours. The material used was PA-CF, known for its exceptional strength, durability, thermal stability, and stiffness.

Using the 3D-printed positive model, the final orthosis was manufactured using the prepreg process (see picture below). First, the carbon fabric was placed on the model, and anchor points for the joints were incorporated (1). Then, a vacuum film was pulled over the carbon fabric to create a vacuum (2). The carbon and resin were heated in an oven at 80 degrees Celsius (3) until the resin cured (4). The advantages of such a carbon orthosis are significant: it is very stable and firm, but above all, it is exceptionally lightweight.

The prepreg process shown from left to right in 4 steps.
The prepreg process shown from left to right in 4 steps as an example. (Source: Rohde)

Impressive Results: Smoother Gait and Improved Fit

Through the combination of traditional craftsmanship techniques and digital solutions, a custom-made orthosis was created for Lea that offers stability and comfort in a previously unattainable form. "My new orthosis is more functional and significantly more customized than the one I had before. It fits perfectly on my leg. It's like a second skin," Lea rejoices. She and Aaron agree that the hybrid manufacturing process sets a new standard for orthopedic fittings.

"Now I can walk more smoothly and experience a better fit. I can finally get going again. I can stand freely, and maybe soon I'll even be able to walk alone," Lea evaluates her new orthosis. Her father is always there to lend a helping hand. And even though she hasn't fully achieved independent walking yet, Lea has already embarked on an incredible journey – she no longer needs the wheelchair, at least for now.

Lea's story is an inspiring example of how the hybrid approach in orthopedic technology can significantly improve patients' lives.

We wish Lea and Aaron all the best for the future and thank them very much for sharing their experience with us. At Mercuris, we are dedicated to developing the most advanced digital tools for professionals like Aaron and patients like Lea.

Would you like to learn more about our digital tools and digital workflows? Get an overview in the webinar recording: "How to Create an AFO Ready for 3D Printing" >>

More on the topic of hybrid process and pre-preg: Learn why Gary Wall, CPO & Clinic Manager at Hanger in Atlanta likes to work with the combination of digital and manual processes. Read all about it in the blog post: Integrating Digital Tailoring with Carbon Fiber Techniques for Custom AFOs/KAFOs

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