The immediate effects of ionomeric and acrylic bone cements on peripheral nerve function

Abstract

A total of 44 rat saphenous nerves were isolated. A pair of stimulating electrodes was positioned distally (at the ankle) to evoke a compound action potential (CAP) which was recorded proximally (in the thigh) through another pair of electrodes. Bone cement was then placed adjacent to the nerve midway between the electrodes and changes in the CAP recorded over a 30-min period. Nerve conduction was completely blocked within 2 min of placing unset acrylic bone cement adjacent to the nerve. The experimental ionomeric cements (IC) also caused a reduction in the nerve conduction although this did not usually occur until the cement had been positioned adjacent to the nerve for over 10 min. Slow-setting IC blocked nerve conduction more quickly than fast-setting IC but there was no apparant difference between the effects of applying materials early or late in the setting reaction. Set ionomeric porous microimplant particles (Ionogran®) had no effect on neural function.

The effects of implanted ionomeric and acrylic bone cements on peripheral nerve function

“…We previously reported that partially set IC had no effect on nerve conduction for over 10 min, whereas acrylic caused conduction block within 2 min [1]. Together with the results from the present specially designed animal experiments, this suggests that if polyalkenoate acid is released from ionomeric cements during gelation it is slow to diffuse through the connective tissues compared with methylmethacrylate monomer.…”

“…In a previous study we demonstrated that neural conduction is blocked within two minutes of placing acrylic cement adjacent to a peripheral nerve [1]. We have also confirmed that if the acrylic is applied in the same way as described in the present experiments, rapid block of nerve conduction occurs.…”

“…Previous investigations carried out in this laboratory have shown that when ionomeric (IC) and acrylic bone cements are placed adjacent to a peripheral nerve trunk they cause a block of axonal conduction [1]. In contrast to our findings, clinical observations on patients following placement of ionomeric cement have not revealed any apparent neural disturbance [2,3].…”

“…Porous microimplant particles (Ionogran R) had no effect on neurone conduction either immediately after it was placed adjacent to a peripheral nerve [1] or after it had been implanted in the tissues for 3 weeks.…”

In vitro biocompatibility of a novel Fe2O3 based glass ionomer cement

“…At this time, however, a number of concerns were raised over the in vivo neurotoxicity of the setting cement. 8,9 Serious adverse events were subsequently reported including death following skull base surgery where relatively large volumes of ionomer bone cement were placed in direct contact with cerebral spinal fluid (CSF) or brain tissue. [10][11][12] While doubts have been since expressed over the surgical approach taken, and current glass ionomer bone cements are now contra-indicated for these clinical applications and concerns remain regarding the biocompatibility of these biomaterials.…”