DCA Design International

Disposable medical devices for wound closure

- Adhesive based wound closure system
- Background research
- Concept generation
- Concept selection and development
- Proving rigs built to test adhesive delivery
- Consideration of existing assembly facilities
- Consideration of detailed manufacturing issues
- CAD modelling of leading concepts
- Close liaison with client

Medlogic approached DCA having developed a new and innovative wound closure technique. The technique uses a specially developed quick-setting, medical grade, cyanoacrylate adhesive to “stitch” together an open wound, either after surgery, or in an accident and emergency situation. Once the wound is successfully closed the next step is to seal the wound area below a waterproof membrane, using a second type of adhesive. This gives the closure both added strength and resistance to infection, whilst still retaining necessary flexibility.
This technique has several advantages over traditional suturing. Wound closure times are reduced and there is no requirement to recall the patient to remove stitches at a later date. In most cases a cleaner scar with no stitch marks is also possible, together with a reduced chance of infection. The technique does however, require the applicator to give the surgeon a high degree of control in the delivery of each adhesive stitch and the secondary membrane film must be easy to apply accurately.
DCA’s brief was to produce an applicator design for the two stage system that would allow the technique to be marketed as an integrated wound closure and dressing technique, using a disposable, single-use, simple to operate applicator.
Testing had shown that the adhesive would need to be stored in thin walled glass ampoules to maintain good shelf life and keep the properties of the adhesive stable. Therefore, a key demand of the project was that in order to be effective the new applicator would need to be primed by first breaking the ampoules.
Surgeons are sometimes reluctant to abandon traditional established techniques and, therefore, in order to become accepted, the new device would need to be exceptionally reliable and simple to use as well as offering a high degree of control to the surgeon. Each ampoule would need to break on demand, first time and with a minimum of effort in order to be ready for immediate use by the surgeon.
DCA approached the project by initially carrying out team brainstorming and development. The most promising concept routes were investigated using simple rigs, so that key aspects of a selection of the concepts could be tested. This included sourcing and testing of suitable sintered plastics for the broad wick required for the wound sealing end of the device, ideas to achieve the correct adhesive flow to the fine tip and a range of ideas to control the breaking of the glass ampoules. DCA then selected the most promising routes and presented them to Medlogic. Discussion followed as to which aspects of the ideas were worthy of further development, before five of the ideas were solid modelled in detail, using 3D CAD, to explore refinements and include further manufacturing considerations. The mix of designs chosen was deliberately diverse so as to fully review options ranging from simple, low risk, solutions to more innovative ideas with higher level development implications and additional benefits. This approach allowed Medlogic to consider the level of risk and investment considered appropriate for the product, before committing to further development.
The product is in full production and proving to be highly successful. It is being used for small wound closure, right through to large and complex closures, such as caesarean sections.
Richard Stenton, Medlogic Managing Director, said,
"Our design collaboration experience with DCA was a very good one. The team were innovative, creative and most importantly achieved the milestones they set in the product development programme. We look forward to working with them again".