Admixture of Calcium Sulfate Pellets


This week, we at SALSA have some patients who have a certain degree of bone involvement in their wounds that might benefit from locally implanting a high degree of antibiotics. This again reminded us of the requests we often received for how to mix medical-grade calcium sulfate with various classes of antibiotics.
Tobramycin, Gentamicin and Vancomycin can be delivered in a biodegradable implant similar to Methylmethacrylate delivery. Be certain there is no allergy or other contraindications for the use of these antibiotics. This will deliver high tissue concentrations with low serum concentrations by an implant that degrades completely over 6-8 weeks.
We frequently get questions regarding how to mix these. This appears to be an excellent venue to post the suggested recipe for the large resorbable and small resorbable bead kits:
 

Large Resorbable Bead Kit (6.0 mm)

The method of mixing: For Tobramycin, use the fast cure BVF kit (Wright Medical) with Vancomycin and the standard BVF kit (Wright Medical) with Gentamycin. 2 grams of Tobramycin, 1 gram of Vancomycin or 1 gram of Vancomycin/Gentamicin may be mixed with the liquid provided with the kit.

Completely blend the antibiotic.

Mix this solution with the powder provided in the kit until completely blended and is free flowing.

Pour the mixture in the blue mold (Wright Medical). Fill all thirty wells completely until the air is out.

Place the other half of the mold into position and squeeze the halves together tightly. The excess material will egress through the vent holes or the sides of the mold.

Hold the mold tightly together for 30 minutes or until hardened.

After hardening, break the mold apart and pop the implants out. This will produce 30 7 mm implants loaded with tobramycin or vacomycin. The loading will be 3-4% by implant weight.

Place the implants in the infected cavity and be sure all dead space is obliterated. The maximum number of medicated implants is one implant/kilogram of body weight. Additional non-medicated Osteoset pellets (Wright Medical) can be used to completely fill the cavity. Good soft tissue coverage is important.

If the wound is closed, it should be drained with closed suction until no significant drainage is evident.

 

 


Small Resorbable Mini-Bead (4.8 mm/3.0) Kit 

Vancomycin Mixture: USE STANDARD CURE SET. Add sterile powder equivalent to 500 mg of Vancomycin to 9.5 gm of osteoset standard cure powder. Add 3 cc of dilutent, and an additional 2 cc of normal sterile saline. Mix per instructions with pellets being produced.

Tobramycin Mixture: USE FAST CURE SET. Add 6 cc of normal sterile saline to vial containing sterile powder equivalent to 1.2 gm of Tobramycin.

This will then bring the tobramycin into solution which is approximately 200 mg of tobramycin per 1 cc of saline. Withdraw 3 cc of saline/ tobramycin mixture. This was then added to 9.5 gm of osteoset fast cure powder. This can then be mixed per instructions with pellets being produced. TO MIMIC OSTEOSET T LOADING DOSE, USE 9 cc OF NORMAL SALINE INSTEAD OF 6.

 

David G. Armstrong

Dedicated to amputation prevention, wound healing, diabetic foot, biotechnology and the intersection between medical devices and consumer electronics.

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