Reviews of the Heraeus Medical Palamix Duo Cement Mixing System | Which Medical Device

The Palamix system from Heraeus is a vacuum cement mixing system that is optimised for the mixing of Palacos cement.

The manufacturer’s product brochure lists the following advantages of the system:

• Effective vacuum generation in 10 seconds
• The ability to mix varying quantities of cement
• A charcoal filter to reduce monomer exposure
• Low residual volumes of cement after mixing
• Good mechanical properties of the mixed cement

The packaging comes with clear instructions which are found inside the outer wrapper (figure 1and 2). The Duo system we have used contains 2 cartridges (one for the acetabulum and one for the femur) a filling funnel, a vacuum hose with indicator and filter, a femoral seal and 2 additional short nozzles (Figure 3). There is no need for a nozzle cutter as the nozzle breaks off for pressurization, and the inclusion of a femoral pressurizer saves the opening of another packet.

In use

Generally speaking, this is a good system that performs well. The funnel for introducing powder and monomer is an excellent design, which allows the opened ampoule to sit up-ended whilst it empties, and which ensures powder and monomer are kept separate until they meet in the barrel (Figure 4). The funnel has a filter to capture glass fragments. There is a bladder attached to the suction tubing, which indicates adequate negative pressure (Figure 5).

Any issues we have had with this system likely relate to unfamiliarity with it and our own processes rather than design or manufacture. For example, the gun has a removable central plunger, which was “misfiled” by our sterilizing department on one occasion. Mixing is generally easy and seems to require less physical strength than the DePuy CemVac system, when used with Palacos. It’s easy to spot if the cement has not been properly mixed, and, although this may not be approved by the manufacturers, you may be able to continue the mixing process by moving the delivery tube up and down, even after the green handle has been removed.

The system is well constructed and the gun feels solid and works reliably after the barrel is screwed into the handle (Figure 6). The green “cap” which is placed on top of the barrel has occasionally leaked cement in use (Figure 7). There was an MHRA alert and the recall of some lots on July 2010 because of an issue with the green closing cap, and it is feasible that some of our systems were affected. Anecdotally, it may be possible to “unscrew” the cap if the user tends to rotate the handle whilst squeezing the trigger when filling the femur, but I have not experienced this. I have had one barrel fail as we were somewhat behind on timing and the cement was going off. I have noticed that depending on the vigour with which the cement is mixed, it can go off a little faster compared with bowl mixing (9 to 10 minutes in my theatre compared with 11 or 12 minutes)

I had previously used the CemVac system for the mixing of Palaos, but found it somewhat difficult to use. Palacos was too viscous for the system and, although pre-chilling the cement made it easier to mix, it was still difficult. The change was made to Palamix after a couple of the barrels split during introduction of the cement.

Conclusion

This is a good system and remains my preferred option for Palacos cement. Care must be taken to ensure the green cap is correctly applied and be aware that polymerization times may be shorter than with other systems.

The author has no financial or other pecuniary interest in the device or device manufacturer reviewed.