Spang & Brands shows pencil point spinal needle with integrated magnifying glass function

temena Pencil-Point Spinalnadel mit Lupe / temena’s pencil point spinal needle with magnifying glass function

temena Pencil-Point Spinalnadel mit Lupe / temena’s pencil point spinal needle with magnifying glass function

Spang & Brands is a one-stop supplier of medical devices and precision parts – from development up to ready-to-use packed products. During COMPAMED, the company shows numerous different medical device solutions for specific application cases on Stand M 33 in Hall 8 A – also in 2-component technology: syringes, cannulae, pierceable membranes, implants, minimal-invasive surgery components, infusion and blood bag sets, transfusion and connection systems, as well as assembled sets and ready-for-sale systems such as mixing and dosing systems for bone cement. As a particular highlight among the Spang & Brands exhibits is a pencil point spinal needle. The company produces the plastic components of this spinal anaesthetics instrument for temena Group.

How can an anaesthetist be sure a needle is precisely positioned before he can apply spinal anaesthesia? By means of a magnifying glass integrated in the spinal needle’s hub, he can immediately detect slightly turbid cerebrospinal fluid. Spang & Bands has developed this control function of the needle in close cooperation with experts at temena Group. This was not, however, the only design feature that the high gloss polished chrome-nickel steel cavities of the injection moulding tool had to tackle.

The pronounced tactile surface plastic parts required for secure guidance of the “introducer” pre-injection cannula, spinal needle and stylet hubs must comply with very tight micro region tolerances. In addition, pointed star-shaped guidance sleeves are moulded into the interiors of the hubs. They ensure that neither misalignment nor other faulty needle/hub positions occur during adhesive assembly of the medical-quality steel needles, which have diameters of 0.33mm to 0.70mm and lengths of 90mm to 150mm. Axial and sliding precision of the four parts with each other is a particular plastics processing challenge. An Anti-Luer connector on the cannula hub prevents mistakes when using anaesthetic syringes. The stylet hub is also fixed exactly by means of a “tongue” in the injection moulded polycarbonate hub. This prevents the stylet from falling out of the needle, even in a vertical position. The stylet hubs are injection moulded in different transparent colours in order to clearly differentiate between different pencil point spinal needles. This colour coding requires use of special UV-transparent PC colour masterbatches to ensure curing of the adhesive used to join metal and plastic.

After several years of development, technical evaluation, validation to international standards and introduction in hospitals, this high-ranking product has meanwhile been in production at Spang & Bands already for quite a while. High precision production of the individual plastic components focusses on compliance with tight 2/100mm tolerances. Systematic precision control is the order of the day, not to the least with the cannula hub’s interior bore, which may not exceed a 2/100mm tolerance limit, in order to take in the maximum 0.33mm diameter needle precisely and with absolute axial straightness. “The required 2/100mm precision is part of our day-to-day business. We have been specialised for around 30 years with continuous growth in engineering knowledge in precision and cleanroom injection moulding for the medical and pharmaceutical industries”, states Friedrich Echterdiek, Managing Director of Spang & Brands GmbH, “in particular for special customer projects, we have the right solution approaches supported by CAD-3D development, MoldFlow analysis, highly modern mouldmaking and over 60 all-electric and hydraulic drive injection moulding machines”. Fully automatic and manual assembly as well as packing parts and sets of components take place in different class cleanrooms – as pre-series or lots delivered just-in-time, from small series up to requirements in millions. Strategically located test stations are equipped with 3D measurement, and both optical as well as tactile controls support quality assurance.