Bone wax

Bone wax is made of beeswax containing a softening agent such as paraffin. Bone wax is used to mechanically stop bone bleeding during surgical procedures. The bone wax is smeared across the bleeding edge of the bone, blocking the holes and causing immediate bone hemostasis through a tamponade effect. Bone wax is supplied in sterile sticks, and most often requires softening before it can be applied. Once applied, it essentially never goes away. Although inexpensive, easy to use and immediate, bone wax has a number of adverse reactions associated with it.

Bone wax inhibits formation of new bone osteogenesis and acts as a physical barrier preventing bone union.

In the presence of bone wax, osteoblasts will be absent in a bone defect. In defects where bone wax was applied and removed after 10 minutes, there was complete inhibition of bone regeneration. For this reason bone wax is almost never used in areas where bone fusion is critical.

Bone wax increases infection rates and impairs the ability of bone to clear bacteria. In the presence of bone wax, the number of bacteria needed to produce osteomyelitis is reduced by a factor of 10,007. In a recent study of infection rates following spinal surgery, surgical site infections occurred in 6 of 42 cases in which bone wax was used, and in only 1 of 72 cases in which it was not used.

Infection and non-union are a particularly important problem in cardiac surgery. According to the American Heart Association, the incidence of deep sternal wound infections is 1% to 5% of patients undergoing coronary artery bypass surgery, with a mortality rate of about 25%.

Bone wax remains as a foreign body for many years, and can cause a giant cell reaction and local inflammation. In skull base surgery, bone wax has been reported to cause granuloma formation and CSF fluid leaks.

The FDA has recently approved a new water soluble bone hemostasis material designed to look and feel like bone wax. This material comprises a sterile mixture of water-soluble alkylene oxide copolymers, derived from ethylene oxide and propylene oxide. These copolymers have a long history in the medical and pharmaceutical fields, and they are considered inert. These compounds are not metabolized, but eliminated from the body unchanged. It is anticipated that with the introduction of these new hemostatic materials, the incidence of surgical bone infections, non-union and inflammatory complications will decrease with time.

The alternative to bone wax is called Ostene. It does not have any of the complications known to occur with the use of traditional bone wax.