Dose-Dependent New Bone Formation by Extracorporeal Shock Wave Application on the Intact Femur of Rabbits

Abstract

Background: Whereas various molecular working mechanisms of shock waves have been demonstrated, no study has assessed in detail the influence of varying energy flux densities (EFD) on new bone formation in vivo. Methods: Thirty Chinchilla bastard rabbits were randomly assigned to 5 groups (EFD 0.0, 0.35, 0.5, 0.9 and 1.2 mJ/mm²) and treated with extracorporeal shock waves at the distal femoral region (1,500 pulses; 1 Hz frequency). To investigate new bone formation, animals were injected with oxytetracycline at days 5–9 after shock wave application and sacrificed on day 10. Histological sections of all animals were examined using broad-band epifluorescent illumination, contact microradiography and Giemsa-Eosin staining. Results: Application of shock waves induced new bone formation beginning with 0.5 mJ/mm² EFD and increasing with 0.9 mJ/mm² and 1.2 mJ/mm². The latter EFD resulted in new bone formation also on the dorsal cortical bone; cortical fractures and periosteal detachment also occurred. Conclusion: Here, for the first time, a threshold level is presented for new bone formation after applying shock waves to intact bone in vivo. The findings of this study are of considerable significance for preventing unwanted side effects in new approaches in the clinical application of shock waves.

The Use of Extracorporeal Shock Wave-Stimulated Periosteal Cells for Orthotopic Bone Generation

“…The ability of ESWs to stimulate periosteal cell proliferation has previously been shown by our group 19 as well as others. 21,22 To our knowledge, to date, however, ESWSP (or ESW-stimulated tissue from any region) has not been combined with scaffolds in a tissue-engineering approach. The advantage of adding a scaffold is three-fold: It contours the new bone, helps maintain bone at the implant site, and creates a space that allows the periosteal cells to further proliferate and fill the scaffold.…”

“…Color images available online at www .liebertonline.com/tea days, the periosteal cells have maximally proliferated but not yet undergone complete osteogenesis. 19,21,22 The ESW treatment site (medial proximal tibia) was chosen, as it is the clinically preferred location of periosteal harvest, 14,23 and we previously demonstrated that tibial periosteal cells are more responsive to ESW stimulation when compared with the femur. 19 There was a significant 2.7-fold increase in the cambium cell number and a significant 4-fold increase in cambium layer thickness; there was also immature bone formation within the proliferated periosteum as previously described.…”

“…19 There was a significant 2.7-fold increase in the cambium cell number and a significant 4-fold increase in cambium layer thickness; there was also immature bone formation within the proliferated periosteum as previously described. 19,21,22 The advantage of the proliferated cell layer is two-fold. First, it is proposed that the increased progenitor cell number will result in increased callus formation and increased osteogenesis within the scaffold.…”

Extracorporeal shockwave therapy (ESWT) – First choice treatment of fracture non-unions?

“…It was assumed that these treatment triggered micro-lesions gaining the capability to stimulate and reactivate bone healing in non-healing fractures. Tischer [3] expressed first doubts of this theory demonstrating new bone formation after shockwave application in healthy femura of rabbits without creating micro-lesions.…”

De novo Generation of an Axially Vascularized Processed Bovine Cancellous-Bone Substitute in the Sheep Arteriovenous-Loop Model

“…7b) illustrates the fact that fibrous tissue and foreign body reaction may be observed instead of bone formation. Still, according to other studies [2,22,26], neobone formation would still be expected in this matrix upon (orthotopic) transplantation into a given bone defect followed by mechanical stimulation [27], or, as in our setting, upon implantation of osteogenic cells and/or osteogenic growth factors [28]. …”