Ever wonder what goes on in the “back office” of an orthotic and prosthetic practice? Most health care professionals involved in the care of physically challenged patients and those who wear prosthetic and/or orthotic devices have never ventured into an O&P fabrication lab or witnessed the decision-making and craftsmanship that goes into the creation of current-generation prosthetic limbs and orthopedic braces. Were they to do so, they would gain a good appreciation of the three essential ingredients of orthotic-prosthetic fabrication:
- Technology – The science and know-how we employ to build the optimum levels of function, comfort and durability into every device;
- Materials – The advanced plastics, metals, fabrics, and other raw components we use to create advanced, functional limbs and braces for every patient; and
- People – The trained and highly skilled personnel whose talent, compassion and experience fulfill the promise of great orthotic and prosthetic designs and thereby help patients realize their lifestyle and vocation goals.
To produce a superior outcome for amputees and individuals requiring orthopedic braces, O&P assistive devices must: (1) fulfill the functional potential of their design, (2) fit intimately and wear comfortably on the patient’s anatomy, and (3) be sufficiently durable to withstand the stresses of daily use.
Present-day prosthetists/orthotists are well-trained to determine their patients’ capabilities, needs and functional desires and to design a prosthetic limb or brace to maximize mobility and lifestyle within those parameters. It remains for the device built to that design to deliver on the promise of the clinician’s vision, a result that inevitably depends on careful, accurate fabrication.
Because of the critical role of the prosthetic socket as the connecting link between human anatomy and prosthesis, most all prosthetic limbs today are custom-fabricated.
Although some bracing needs can be solved with prefabricated products, the majority of orthosis designs depend on a precise, total-contact fit and thus require custom manufacture.
An off-the-shelf device is modified and adjusted to achieve the best result possible, given that its fit is, at best, an approximation.
Custom prostheses and orthoses, on the other hand, are one-of-a-kind devices molded intimately to a cast or computer-generated model of the patient’s anatomy to deliver the best result possible.
How Great Prosthetic Limbs And Orthoses Come To Life
In standard casting, a plaster of Paris bandage or water-activated synthetic casting tape is wrapped around the affected limb or torso to create a three-dimensional mold. Upon hardening, the mold is carefully removed, sealed and filled with plaster to create a positive model of the body segment on which the prosthetic socket or orthosis will be formed.
A contemporary alternative, computer-aided design (CAD), allows practitioners to design and modify O&P components with mouse and monitor. Once completed, the design can be exported to a computer-aided manufacturing (CAM) carver to generate a foam positive model. A hybrid option utilizes a laser scanning device to digitize the interior contours of a traditional mold, allowing the practitioner to then rectify the model electronically.
After initial casting or digitizing, the prosthetist-orthotist modifies the design to build in therapeutic strategies, provide focused additional support as needed, accommodate anatomical irregularities and enhance patient comfort.
The more intimate the fit and the greater the comfort, the better the functional outcome, so the importance of an accurate and properly modified model cannot be overstated… nor can the actual fabrication process. Many prosthetist/orthotists choose to be directly involved in turning their designs into reality, while others rely on trusted technical support personnel for fabrication allowing the practitioners to focus their attention on direct patient care.
A well-equipped O&P laboratory incorporates work benches, specialized tools and equipment, a supply of plastics, metals, fabrics, foams, leather and other raw materials, and safety mechanisms to ensure fabrication is performed in a safe environment for staff and surrounding areas.
The introduction of sheet thermoplastics and thermoset plastic laminations has revolutionized the fabrication of limbs and braces, providing a total-contact fit and superior strength in a lightweight package. In both upper- and lower-extremity prosthetic limbs, custom sockets form the key interface between anatomical remnant and replacement limb.
Getting the socket right is critical to functional success; thus, one or more check, or test, sockets of transparent plastic may be fabricated to ensure an optimal fit. When the definitive (final) socket is ready, the limb is completed with various pre-made components (feet, knees, pylons, hand units, etc.) chosen specifically for that patient.
Plastics are used to an even greater extent in orthosis construction, notably in ankle-foot orthoses (AFOs), spinal braces, upper-extremity orthoses and cranial remolding helmets. Various foams and fabrics are added for enhanced comfort and skin protection. Fabrication time can vary considerably depending on design complexity and patient characteristics.
Some devices can be made in hours; others take many days. Our intention is to take whatever time is necessary – but no more – to fabricate every limb/brace as “right” as we possibly can.
We welcome your questions and comments regarding the fabrication process. Our offices are located in Beaumont, Nederland and Jasper, Texas.