Experimental Study Of Prosthetic Titanium Ribs On The Reconstruction Of Chest Wall Defects In Rabbits

Objective:The most common etiological factors of chest wall defects include trauma,tumor,infection,radiation necrosis and congenital deformities.Large defects of the anterior or lateral chest walls can lead to the damage of thoracic integrity and stability,resulting in paradoxical respiration and other respiratory dysfunctions.Therefore,it's important for the reconstruction of large chest wall defects to attain a fine functional and cosmetic result.In recent years,a variety of artificial materials have been applied to the chest wall reconstruction in clinics.However,there is no ideal repair material available until now.The reconstruction of large defects remains a challenging problem for thoracic surgeons.Titanium and its alloys have been widely used in several surgical fields,such as craniofacial reconstruction and orthopedic prosthesis.This prosthesis has been proved to be not only good biocompatibility,mechanical strength and corrosion resistance,but also light weight and low radiological interference.In this study,we repaired chest wall defects with the prosthetic titanium ribs by means of coarsening surface with sandblasting and acid etching(SLA)in rabbits.The purpose of this experiment was to investigate the application of prosthetic titanium ribs for reconstruction of large chest wall defects,so as to assess its feasibility in clinical chest wall reconstruction.Methods:Prosthetic titanium ribs were prepared by means of coarsening surface with sandblasting and acid etching(SLA).Large chest wall defects of 3cm×3cm were created in 20 rabbits and then randomly divided into 2 groups: the study group and the control group.In the study group(n=10),the defects were repaired by the titanium implants,while in the control group(n=10),the defects were replaced with the autogenous ribs with periosteum.Biochemical blood parameters such as serum levels of alkaline phosphatase(ALP),calcium and phosphorus were measured before surgery(time 0)and 1,2,4,6,8,10,12 weeks after operation.Chest radiography and pathohistological examinations were performed in 4,8,12 weeks after operation to dynamically observe the progress of Bone healing.Results:No intraoperative and postoperative deaths were observed in both groups;flail chest,paradoxical breathing and infections were not found in all the rabbits.The serum ALP concentrations followed the same pattern in both groups, decreased from 1 weeks to 6 weeks,lowest at 6 weeks and then increased.The calcium-phosphorus products reached peak value at 1 week and then gradually decreased from 6 weeks.No significant differences were found in both the serum ALP concentrations and the calcium-phosphorus products in the two groups(P＞0.05).In the study group,expected bone-to-implant contact was achieved,with a large amount of new bone tissues appeared in the interface without forming the fibrous tissue;while in the control group,osteogenesis in the broken ends of the ribs was evident with continuous callus formation.Conclusion:The results of this study demonstrated that chest wall reconstruction using prosthetic titanium ribs with the coarsening surface could provide an effective support to the defected chest wall.This prosthesis has fine biocompatbility,mechanical strength and corrosion resistance.After the implantation into the defects,the prosthetic titanium rib can achieve successful osseointegration,which makes it a promising prosthesis for the reconstruction of large chest wall defects and deserves further researches in the clinical application.