The effect of ultrasound on the healing of muscle-pediculated bone graft in spinal fusion.

STUDY DESIGN

A rabbit model of posterolateral intertransverse process spine arthrodesis with and without the application of low-intensity ultrasound was used.

OBJECTIVE

To determine the effects of low-intensity ultrasound on the healing of muscle-pediculated bone graft.

SUMMARY OF BACKGROUND DATA

Earlier animal and clinical studies demonstrated the efficacy of low-intensity ultrasound stimulation in the acceleration of osteogenesis and fracture healing. This is the first study in which the beneficial effects of ultrasound on the healing of muscle-pediculated bone graft in spinal fusion have been assessed.

METHODS

In this study, 20 New Zealand rabbits were randomly assigned to two groups to undergo either spinal fusion using muscle-pedicle bone graft with ultrasound (ultrasound group) or muscle-pedicle bone graft without ultrasound (control group). Muscle-pediculated bone grafts were prepared from the posterosuperior iliac crest, erector spine muscle, and internal and external oblique muscle. This graft was placed bilaterally between the L5 and L6 transverse processes. Ultrasound was performed 20 minutes per day over the rabbits' lumbar spine. The rabbits were killed 6 weeks after surgery. The lumbar spines were evaluated radiologically, macroscopically, and histologically.

RESULTS

By macroscopic and radiologic findings, fusion was detected in 11 control group rabbits (55%) of the control group, and in 17 ultrasound group rabbits (85%). The fusion success rate for the rabbits treated with low-intensity ultrasound were statistically higher (P <0,05) than that for the control group. Histologic specimens showed increased bone formation in the fusions exposed to ultrasound. Mature fusions were present in rabbits that received ultrasound.

CONCLUSION

Low-intensity ultrasound in white rabbits increased the rate and quality of spinal fusion using muscle-pediculated bone grafts.