MPMN: March 1997
Partnership Breathes New Life
into an Innovative Device
Two companies work together to design, manufacture, and sell a dynamic product
A common problem for manufacturers sometimes arises with the introduction of a product that is dynamic and innovative, but that has to be modified to pass stringent requirements and be easier to manufacture. Such was the case with the Sure Closure skin stretcher, a device designed for treating open wounds. Instead of letting skin heal naturally, which can cause a traumatic skin graft or flap, the device stretches the skin by taking advantage of its natural viscoelastic properties.
The Sure Closure skin stretcher was developed in Israel to treat wounded soldiers of the Israeli army. Although it was a breakthrough in medical treatment, the original product was made of metal and had many inherent deficiencies. MedChem Products (Woburn, MA), a medical device manufacturer, saw the product's potential and purchased the rights to it.
The prototype stainless-steel models presented a problem: the tension that was applied across the wound could not be reliably or consistently duplicated from patient to patient. This prompted MedChem to seek to develop a disposable plastic skin stretcher for one-time use. To produce the new version, MedChem turned to The MedTech Group Inc. (South Plainfield, NJ), a medical products injection molder.
Eric Rozier, the project manager for MedTech and key liaison with MedChem, attributes the successful commercialization of the Sure Closure skin stretcher, which took less than a year, to a multidisciplinary team approach. This approach enabled the companies' joint project teams to quickly implement changes. "Assembly, packaging, and sterilization were all developed concurrently with the first injection-molded components," says Rozier.
For easy manufacturing and lower cost, the entire Sure Closure skin stretcher is snapped together, including metal-into-plastic and plastic-into-plastic assemblies. Rozier notes that the development of the product was no easy task. Since the system consists of nine complex molded components and four steel parts, a great deal of mechanical functionality needed to be built in, including systems that engage and disengage a drive system automatically when a preset force is applied.
One component involves a one-half molded thread that must slide smoothly in one direction and must accurately hold a preset force in the other direction without stripping. Since a 2.5-kg force is held continuously for up to two days by the device, design and material selection were critical.
