EFFECT OF CAPACITIVE COUPLED ELECTRICAL-STIMULATION ON REGENERATE BONE

An in vivo study was carried out to determine if capacitive coupled el ectrical stimulation increased the rate of recovery of strength of reg enerate bone produced as a result of lengthening bq the Ilizarov techn ique. Thirty-four adult male beagles underwent a right tibial mid-diap hyseal corticotomy, followed by a 5-day delay, and then 21 days of len gthening (1 mm/day). At the start of the post-distraction period (day 27), stimulation (3-6.3 V peak to peak. 5-10 mA root-mean-square at 60 kHz) was applied for 28 days to one group. The nonstimulated group (n = 17) underwent a 28-day period with no stimulation, From each group, four tibiae were prepared for histology, both ends of the remaining b ones were embedded in polymethylmethacrylate and tested in torsion (in ternal rotation at 4.7 degrees/sec) until failure. Statistically signi ficant changes included a 37% lower maximum torque capacity and a 40% decrease in strain energy to failure in the stimulated group compared with the nonstimulated group. The findings are supported by measured t rends to a lower modulus of rigidity (37% decrease) and a smaller perc entage of active osteoid perimeter (20% decrease) for the stimulated g roup, The experimental data suggest that when this dose of capacitive coupled electrical stimulation is applied to the regenerating bone cre ated during distraction osteogenesis, it delays the recovery of bone s trength compared with an untreated control.