Studying the strength of the tibia during the replacement of a post-resection defect with a segmental allograft using locked intramedullary nailing (experimental clinical study)

Background. To achieve success in the incorporation of allografts and bone of the recipient, many factors are taken into account, which can be divided into two main groups: those related to sterilization and processing of the bone allograft and factors affecting the reliability of implant fixation in the bone of the recipient. The second important factor is the method for fixing the allografts and the bone of the recipient. The purpose was to determine the mechanical properties of bone after segmental bone alloplasty. Materials and methods. Female patient Sh., 30 years old, diagnosed with osteosarcoma of the left distal tibia T2N0M0 GIII, degree II, clinical group II, underwent polychemotherapy courses, surgical intervention according to the developed method. The tumor was removed en block, a post-resection defect was replaced with an articulating segmental bone allograft, fixed to the recipient’s bone through a stepped osteotomy and an intramedullary locked nail. Bone autografts were additionally placed into the area of the allograft contact with the recipient’s bone. After 2 years, the patient underwent surgery: amputation at the left third of the thigh. Radiographically, fusion of the allograft and the recipient’s bone was noted. An experimental study of the tensile strength of the tibia after segmental alloplasty of a post-resection defect was carried out using the developed surgical technique and a segmental allograft. Results. To compare the results of an experimental study of the tibia preparation after segmental bone alloplasty, data about the values of the ultimate strength of the bone tissue under compression and bending loads were selected. As shown by the experiment, the ultimate strength of the tibia preparation after its bone alloplasty was 51.82 MPa. This value corresponds to the minimum ultimate strength of a compact bone in bending — 51 MPa. Although this is twice as low as the maximum value of the ultimate strength of a compact bone in bending (133 MPa), it should be borne in mind that all the given reference values were obtained when testing intact preparations of a compact bone. Conclusions. The use of a segmental bone allograft to replace a post-resection defect in a long bone with its fixation to the recipient’s bone through a stepped osteotomy and locked intramedullary nailing with additional bone autoplasty in the area of the allograft contact with the recipient’s bone makes it possible to obtain in the osteotomy zone the bone, the ultimate strength of which corresponds to that of the intact tissue.

A 24-month retrospective update: follow-up hospitalization charges and readmissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2)

Background The objectives of this study were to build upon previously-reported 12-month findings by retrospectively comparing 24-month follow-up hospitalization charges and potentially-relevant readmissions in US lumbar fusion surgeries that employed either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a nationwide healthcare system database. Methods A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2 in the original study, of whom 3,792 patients (23.4%) were identified in the current study with all-cause readmissions during the 24-month follow-up period. Confounding baseline patient, procedure, and hospital characteristics found in the original study were used to adjust multivariate regression models comparing differences in 24-month follow-up hospitalization charges (in 2020 US dollars) and lengths of stay (LOS; in days) between the groups. Differences in potentially-relevant follow-up readmissions were also compared, and all analyses were repeated in the subset of patients who only received treatment at a single level of the spine. Results The adjusted cumulative mean 24-month follow-up hospitalization charges in the full cohort were significantly lower in the V-CBA group ($99,087) versus the rhBMP-2 group ($124,389; P < 0.0001), and this pattern remained in the single-level cohort (V-CBA = $104,906 vs rhBMP-2 = $125,311; P = 0.0006). There were no differences between groups in adjusted cumulative mean LOS in either cohort. Differences in the rates of follow-up readmissions aligned with baseline comorbidities originally reported for the initial procedure. Subsequent lumbar fusion rates were significantly lower for V-CBA patients in the full cohort (10.12% vs 12.00%; P = 0.0002) and similar between groups in the single-level cohort, in spite of V-CBA patients having significantly higher rates of baseline comorbidities that could negatively impact clinical outcomes, including bony fusion. Conclusions The results of this study suggest that use of V-CBA for lumbar fusion surgeries performed in the US is associated with substantially lower 24-month follow-up hospitalization charges versus rhBMP-2, with both exhibiting similar rates of subsequent lumbar fusion procedures and potentially-relevant readmissions.

Immediate Mandibular Reconstruction Using a Cellular Bone Allograft Following Tumor Resection in a Pediatric Patient

Reconstruction of large segmental mandibular defects presents a challenge for oral and maxillofacial surgeons, particularly in the skeletally immature pediatric patient. Autogenous bone graft is historically preferred; however, harvest of autograft requires a second surgical site, risking donor-site complications as well as the potential for long-term complications in the growing child. Here, we present the first known report of a pediatric patient who underwent immediate mandibular reconstruction of a 6.5-cm long segmental defect using a cellular bone allograft (VF-CBA) combined with custom-fabricated guides and plates following tumor resection. The use of VF-CBA, along with the custom guides and plates, eliminated the need for autograft harvest in a child, enabled an entirely intraoral approach, avoiding the creation of a cutaneous scar, and reduced the total operative time, resulting in a fast recovery and improved patient satisfaction. By 7 months postoperative, the patient’s mandible was fully healed with solid osseous consolidation. These results support VF-CBA combined with custom intraoral guides and plates as an effective treatment option for reconstruction of large segmental mandibular defects in a pediatric patient.

Investigation of Antibiotic Release from Bone Allograft in an Experiment on Rabbits

BACKGROUND: The treatment of chronic osteomyelitis, despite the use of new methods, is still an urgent problem. Local use of antibacterial drugs in combination with systemic antibiotic therapy has become popular in recent decades. Autologous bone grafts are considered ideal for bone defects filling. Different methods of allograft preparation may have differences in the rate and duration of antibiotic release. Moreover, it can affect the effectiveness of microbial agent eradication. The study analyzed the differences in the release of gentamicin from different types of allografts in dynamics and methods of preparation: «PerOssal» medium, whole bone allograft soaked in antibiotic, whole bone allograft, welded with an antibiotic, and perforated bone allograft soaked in an antibiotic solution. AIM: The objective of the study was to study the stability of antibiotic release and to determine the effectiveness of local transport systems. Evaluation of the difference in gentamicin release from different types of allografts in dynamics and methods of preparation had been realized: “PerOssal” medium, whole bone allograft soaked in antibiotic, whole bone allograft welded with an antibiotic, and perforated bone allograft, soaked in antibiotic solution. MATERIALS AND METHODS: The research was conducted between September 2020 and March 2021. The experiments were performed on 120 laboratory rabbits (weight – 3000–3500 g, age – 6–8 months), which were divided into four groups (30 animals in each group). Group 1 consisted of animals treated with “PerOssal.” The whole bone allograft soaked in an antibiotic was used in the treatment of animals of Group 2. The whole bone allograft, welded with an antibiotic, was used in the treatment of animals of Group 3. Perforated bone allograft soaked in an antibiotic was used in Group 4. Osteomyelitis of the proximal femur was formed in experimental animals. RESULTS AND DISCUSSION: Statistically insignificant decrease in the concentration of gentamicin was observed by the 7th day in all experimental groups. In rabbits whose bone defect was filled with a whole bone allograft welded with antibiotic and perforated bone allograft impregnated with an antibiotic (Groups 3 and 4), the most stable concentration of gentamicin was noted throughout the study period. Statistically significant differences were revealed between the experimental groups in relation to the dynamics of changes in the concentration of gentamicin in blood plasma. It was found that the group using the biodegradable material “PerOssal” on the 1st day showed a high concentration of the antibiotic in the blood plasma. However, by the 2nd day, a lower concentration of the antibiotic was recorded compared to all comparison groups of the bone allograft. CONCLUSIONS: The results of the analysis of the dynamics of gentamicin concentration may indicate significant differences between the methods of graft preparation, especially in the relationship with antibiotic release into the blood plasma. The most stable antibiotic concentration was registered in the groups of animals that underwent the filling of bone defect using a whole bone allograft welded with an antibiotic and a perforated bone allograft impregnated with antibiotic. A significant decrease of gentamicin concentration in the femur homogenate by the 7th day after transplantation was observed when using a whole bone allograft impregnated with an antibiotic. At the same time, a stable concentration of the antibiotic in the blood plasma was registered. The highest initial antibiotic concentration in the homogenate with a gradual decrease over 7 days was observed when using the antibiotic-impregnated biodegradable material “PerOssal.”

EVALUATION OF EFFICACY OF DEMINERALIZED FREEZE DRIED BONE ALLOGRAFT WITH AND WITHOUT PLATELET-RICH FIBRIN IN THE TREATMENT OF INTRABONY DEFECTS BY CONE BEAM COMPUTED TOMOGRAPHY: A CLINICAL AND RADIOGRAPHIC STUDY

Background: Eventhough the combination of DFDBA (demineralized freeze dried bone allograft) with PRF (platelet-rich fibrin) has been attempted in periodontal practice with significant results, assessment of the intrabony defect and defect bone fill largely done with two-dimensional imaging modalities. Three dimentional analysis of the intrabony defect and defect bone fill has not been attempted with cone beam computer tomography (CBCT). The present study evaluated the efficacy of DFDBA with and without PRF in the treatment ofintrabony defects by CBCT. Methods: 60 defects in systemically healthy patients ranging from 18 to 50 years of age will be included in the study.30 defects were treated with PRF+DFDBA and 30 defects were treated with DFDBA alone. The study will include the assessment of clinical parameters involving probing depth (PD), relative attachment level(RAL), full mouth bleeding scores(FMBS),plaque index and gingival index from baseline to 3 , 6, 9 months. Hard tissue changes will be assessed radiographically by evaluating defect fill and defect resolution by CBCT at baseline& 9 months. Results: The results of the present study are statistically significant in both groups in terms of clinical and radiographical parameters (P < 0.001). In inter-group comparison, there was a statistically significant greater PD reduction and attachment gain while there was not significant reduction in terms of PI, GI, FMBS, defect fill and defect resolution in DFDBA+ PRF group. Conclusion: DFDBA along with PRF failed to provide additional value in terms of defect fill and defect resolution over DFDBA alone.