Pasteurized intercalary autogenous bone graft: radiographic and scintigraphic features

Case report: Limb-sparing surgery of tibial chondrosarcoma with frozen autologous bone graft using liquid nitrogen in a dog

Chondrosarcoma is the second most common primary bone tumor after osteosarcoma in dogs. Chondrosarcoma has a good prognosis owing to its low metastatic rate and long survival time, even with amputation alone. However, amputation risks reducing the quality of life in patients with other orthopedic diseases of the non-affected limb, neurological diseases, or large body size. Limb-sparing surgery with frozen autologous bone grafting using liquid nitrogen allows bone quality to be maintained in the normal bone area while killing tumor cells, thereby preserving the affected limb. Thus, it is expected to maintain the quality of life. We describe herein limb-sparing surgery for tibial chondrosarcoma with frozen autologous bone graft using liquid nitrogen in an 8-year and 8-month-old castrated male bulldog weighing 29.2 kg. The patient had chondrosarcoma of the left tibia, suspected cranial cruciate ligament rupture of the right stifle, and degenerative lumbosacral stenosis. In such a case, amputation would increase the burden on the non-affected limb or spine, which could cause difficulty in walking; therefore, we performed limb-sparing surgery. Postoperatively, although a circumduction gait associated with stifle arthrodesis remained, the patient maintained the quality of life for 20 months, and the owner was satisfied with the results.

Development of a novel regenerative therapy for malignant bone tumors using an autograft containing tumor inactivated by high hydrostatic pressurization (HHP)

Surgical resection of malignant bone tumors leads to significant defects in the normal surrounding tissues that should be reconstructed to avoid amputation. Our research aimed to inactivate osteosarcoma (OS)-affected bone to obtain autologous bone grafts for bone defect reconstruction using a novel therapy called high hydrostatic pressurization (HHP) therapy. The key points are complete tumor death and preservation of the non-denatured native extracellular matrix (ECM) and bone tissue by HHP. Previously, we found that HHP at 200 MPa for 10 min can completely inactivate cells in normal skin and skin tumors, including malignant melanoma and squamous cell carcinoma while maintaining their original biochemical properties and biological components. Based on our previous research, this study used HHP at 200 MPa for 10 min to eradicate OS. We prepared an OS cell line (LM8), pressurized it at 200 MPa for 10 min, and confirmed its inactivation through morphological observation, WST-8 assay, and live/dead assay. We then injected OS cells with or without HHP into the bone marrow of the murine tibia, after which we implanted tumor tissues with or without HHP into the anterior surface of the tibia. After HHP, OS cells did not proliferate and were assessed using a live/dead assay. The pressurized cells and tumors did not grow after implantation. The pressurized bone was well prepared as tumor-free autologous bone tissues, resulting in the complete eradication of OS. This straightforward and short-pressing treatment was proven to process the tumor-affected bone to make a transplantable and tumor-free autologous bone substitute.

A Viability Analysis of Tumor-Bearing Frozen Autograft for the Reconstruction After Resection of Malignant Bone Tumors Using 99m Tc-MDP Scintigraphy

PURPOSE OF THE REPORT

Several methods are used to reconstruct bony defects after malignant tumor excision. Tumor-bearing frozen autograft reconstruction is a biological procedure in which tumor-bearing bone is reused after devitalization with liquid nitrogen to kill tumor cells. The viability of frozen autografts has not been fully evaluated over time. We therefore aimed to evaluate the viability of devitalized bone grafts, using 99m Tc-MDP scintigraphy.

PATIENTS AND METHODS

Seventy-four patients who underwent frozen autograft reconstruction after the excision of a malignant bone tumor were enrolled. Two hundred forty-two postoperative 99m Tc-MDP scans were reviewed. For a quantitative analysis, the region of interest on the frozen bone segment and a symmetric region of interest on the contralateral normal area were manually set. The radioactive tracer uptake ratio was calculated by dividing the count density of the frozen bone segment by that of the contralateral normal area in each image. An uptake ratio of 0.9 to 1.1 was defined as a normalization of tracer uptake.

RESULTS

Normalization of tracer uptake was achieved in 95% to 97% of the cases by 60 months postoperatively, and earlier in the middle zone and peripheral zone in the pedicle freezing group in comparison to the free freezing group (both P = 0.03). Fracture and nonunion was associated with a low uptake ratio, whereas infection was associated with a high uptake ratio before the occurrence of the event.

CONCLUSIONS

The calculation of the uptake ratio using 99m Tc-MDP scans was an objective and accurate evaluation method. The period to normalization of tracer uptake in the pedicle frozen bone was significantly earlier than that in the free frozen bone. The postoperative complications can be also predicted.

Assessment of the Viability and Union Feature of Diaphysis Reconstruction Using Pasteurized Tumor Bone and Intramedullary Free Fibular After Tumor Resection

BACKGROUND

Reconstruction using pasteurized tumor bone (PTM) and intramedullary-placed vascularized free fibular (VFG) has the combined advantages of mechanical strength and biological activity. The aims of this study were to investigate scintigraphic viability and radiographic union patterns of composite grafts after surgery, union rates, functional outcomes, and complication rates.

METHODS

Seventeen patients underwent intercalary composite reconstruction using PTM and VFG (12 male, 2 female, mean age: 10.9 y). Retrospective evaluation of radiography and bone scintigraphy was performed. The most common diagnosis was osteosarcoma (12/14, 85.7%). All radiography and bone scintigraphy was reviewed for bone healing and tracer uptake semiquantitatively using the ratio of the reconstructed portion to the contralateral side. Complications and oncological and functional outcomes were recorded.

RESULTS

At a mean follow-up of 33.1 months, primary union was achieved in all 28 host-graft junctions in all 14 patients. The respective mean times to proximal and distal junction bone union were 6.9 and 6.5 months. Metaphyseal junctions healed faster than diaphysis junctions (5.2 vs. 8.0 mo, P=0.02). Free fibular was integrated with surrounding bone after a mean of 10.1 months. The mean tracer uptake ratio was 1.1 after a mean of 4.8 months postoperatively. Half patients (50%) had higher uptake on bone scan than contralateral side. There was no significant correlation between uptake value and bone healing time. Five complications occurred in 4 patients (28.6%), and 1 patient (7.1%) contracted an infection. No fractures or breakages were observed. The mean Musculoskeletal Tumor Society 93 score was 87.6%.

CONCLUSIONS

Reconstruction using PTM combined with VFG is associated with good short-term biological activity as indicated by bone scintigraphy, a high union rate, and an acceptable complication rate. The technique is a useful reconstruction option for large segmental bone defects after tumor resection in lower extremities.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Reconstruction of the elbow using pedicle joint freezing after wide excision for soft tissue sarcoma: A case report

A 35-year-old man presented with a four-year history of a growing mass on the anterior aspect of his left elbow. Magnetic resonance imaging revealed a soft tissue tumor in the brachialis muscle extending to the cubital fossa. Following an open biopsy, the tumor was diagnosed as a monophasic fibrous synovial sarcoma. After neoadjuvant chemotherapy, the patient underwent wide excision and reconstruction of the elbow joint with a pedicle frozen autograft. At the final follow-up four years after surgery, the elbow range of motion was 0-120˚. Although there were signs of osteoarthritis, there was no narrowing of the joint -, and the patient experienced only mild pain. To the best of our knowledge, the present case report is the first to describe wide tumor excision and reconstruction using a pedicle frozen autograft of the elbow. This method should be considered after excision of malignant bone and soft tissue tumors, especially in non-weight-bearing joints. Further cases have to be evaluated to understand the complications and long-term prognosis of this procedure.

Efficacy of frozen autograft treated with liquid nitrogen in limb-sparing surgery in feline scapular osteosarcoma: A case report

In recent years, a novel technique of limb preservation has been used in human medicine that involves frozen autograft treated with liquid nitrogen. In this case, frozen autograft treatment along with shoulder joint reconstruction was performed in an 11-year-old cat with osteosarcoma of the distal scapula. Surgical site infection, shoulder dislocation, local recurrence, and pulmonary metastases were not reported for 24 months after surgery. Moreover, the patient was able to bear weight on the operated limb after 2 months of surgery, and excellent limb function without lameness was demonstrated after 15 months. The frozen autograft technique is advantageous because it is inexpensive, simple, and retains its initial strength after treatment, and could be a novel treatment in feline osteosarcoma.

Histological findings of regeneration in retrieved pasteurized bone grafts

BACKGROUND

Despite a number of radiologic evaluations of the incorporation of pasteurized bone (PB) in human and histologic evaluations in animal models, there has been a scarce documentation regarding the histologic evaluation of PB from human. Herein, we present histologic findings of regeneration in retrieved PB graft from pediatric and adult patients.

METHODS

PB was retrieved for various reasons in 7 patients (10-52 years old). Two bone pathologists independently counted the number of empty lacunae and lacunae with living cells in up to 10 randomly selected fields on medium-power (H&E, ×200) for each patient. Regeneration of PB was assessed as the ratio of the number of lacunae with nucleated cells to that of whole lacunae, which was defined as the "repair rate (RR)".

RESULTS

The mean interval between initial reconstruction and retrieval (graft removal time; GRT) was 47.4 months (range, 11-144 months). The length of original PBs ranged from 5.8 to 20.6 cm. Microscopic examination of PBs showed areas with empty lacunae indicating necrosis and other areas contained lacunae with nucleated osteocytes, indicative of regeneration. Some Haversian canals of the PBs were filled with fibrovascular tissue and surrounded by lamellar bones including living osteocytes. RR varied widely from 21.7 to 62.4% with a mean of 36.8%. It was much higher in adult patients (46.6-62.4%, mean = 55.3%) than in pediatric patients (21.7-28.6%, mean = 25.3%), which was correlated with GRT (pediatric patients; mean of 14 months, adult patients; mean of 72.3 months). In adult patients, RR was higher in a patient with prosthesis composite in the proximal humerus (Case No. 3; 62.4%).

CONCLUSIONS

RR was higher in whom GRT was longer, being correlated with GRT in retrieved PBs. In terms of our histological observation, PB is thought to be an acceptable temporary biologic spacer in limb-sparing surgery for malignant bone or soft tissue tumors.

Are Pasteurized Autografts Durable for Reconstructions After Bone Tumor Resections?

BACKGROUND

Pasteurized autograft is regarded as a biologic reconstructive option for managing bone defects after tumor resection; however, reports on long-term outcomes from large patient series are scarce. Contrary to previous favorable reports, we have observed many patients with failures, in particular as the duration of followup increased. Because pasteurized autografts are used in many countries as a reconstruction option, we wished to formally evaluate patients who underwent this approach at one specialty center.

QUESTIONS/PURPOSES

(1) What is the graft survival and what proportion of patients achieved union when pasteurized autografts were used for bone defects after tumor resection? (2) What are the complications and causes of graft removal? (3) What factors are related to the likelihood of union and graft survival? (4) What is the survival and cause of failure by type of pasteurized autograft reconstruction?

METHODS

Over a 26-year period from 1988 to 2013, we performed 1358 tumor resections in our center. Of these, 353 were reconstructed with pasteurized autograft. Other reconstructions included endoprostheses (508 patients), instant arthrodesis using an intramedullary nail and bone cement (286 patients), allografts (97 patients), and resection only (114 patients). During the period in question, we generally used this approach when tumor showed an osteoblastic pattern and less than one-third cortical destruction in osteolytic tumor. We generally avoided this approach when the tumor showed an extensive osteolytic pattern. We excluded 75 (21% [75 of 353]) patients, 21 (6% [21 of 353]) for incomplete clinical data and 54 (15% [54 of 353]) with a followup < 2 years or those lost to followup leaving 278 autografts eligible. The mean followup was 113 months (range, 25-295 months). Of these 278 patients, 242 patients had primary bone sarcomas, 22 patients had soft tissue tumor invading bone, seven patients had metastatic carcinoma, and seven patients had aggressive benign bone tumors. From a chart review, we obtained the age, sex, location, tumor volume, histologic diagnosis, use of chemotherapy, graft length, fixation modality, type of pasteurized bone used, proportion of union, complications, and oncologic outcome of the patients. In total, 377 junctional sites were assessed for union with serial radiographs. We defined junctions showing union < 2 years as union and > 2 years as delayed union. We grouped our patients into type of pasteurized bone use: pasteurized autograft-prosthesis composites (PPCs) were performed in 149, intercalary grafts in 71, hemicortical grafts in 15, osteoarticular in 12, and fusion of a joint in 31 patients. The endpoint of interest included removal of the autograft with implant loosening, infection, fracture of the graft, or any reoperation resulting in removal. Survival of the graft was determined by Kaplan-Meier plot and intergroup differences were determined using log-rank test.

RESULTS

Five, 10-, and 20-year survival of 278 autografts was 73% ± 5.5%, 59% ± 6.7%, and 40% ± 13.6%, respectively. Of 278 autografts, 105 (38%) were removed with complications. Cause of removal included infection in 13% (33 patients), nonunion in 7% (18 patients), fracture of graft in 6% (16 patients), resorption of the graft in 5% (14 patients), and local recurrence in 4% (11 patients). Univariate survival analysis revealed that patient age ≤ 15 years (p = 0.027; hazard ratio [HR], 1.541), male sex (p = 0.004; HR, 1.810), and pelvic location (p = 0.05; HR, 2.518) were associated with graft removal. The 20-year survival rate of osteoarticular and hemicortical methods was 92% (95% confidence interval, -15.6% to +8.3%) and 80% ± 20%, respectively. For intercalary and fusion, it was 46% ± 15% and 28% ± 22%, respectively, although for PPC, it was 37% ± 22%. Log-rank survival analysis showed the osteoarticular and hemicortical groups had better graft survival compared with other types of reconstruction (p = 0.028; HR, 0.499). The most prevalent cause of graft removal in three major types of reconstruction was as follows: (1) PPC type was infection (30% [17 of 56]); (2) intercalary graft was infection, nonunion, and local recurrence in even proportions of 29% (86% [24 of 28]); and (3) fusion was infection (35% [six of 17]). Two hundred ten (56%) of 377 junctional sites showed union within 2 years (average, 14 months), 51 (13%) junctions showed delayed union after 2 years (average, 40 months), and the remaining 116 (31%) junctions showed nonunion. Diaphyseal junction (p = 0.029) and male sex (p = 0.004) showed a higher proportion of nonunion by univariate analysis.

CONCLUSIONS

Compared with the favorable short-term and small cohort reports, survival of pasteurized autograft in this long-term large cohort was disappointing. We believe that pasteurized autograft should be used with caution in children and adolescents, in the pelvic region, and in PPC form. When bone stock destruction is minimal, it is worth considering this approach for small intercalary or distal long bone reconstruction. We believe this procedure is best indicated after hemicortical resection of long bone.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Long-term clinical outcome of sacral chondrosarcoma treated by total en bloc sacrectomy and reconstruction of lumbosacral and pelvic ring using intraoperative extracorporeal irradiated autologous tumor-bearing sacrum: a case report with 10 years follow-up

BACKGROUND CONTEXT

Primary malignant tumors of the sacrum are rare. Chondrosarcoma is one of the common malignant tumors arising from the sacrum. Chondrosarcoma is often invasive, and there is a high propensity for local recurrence. Surgical resection is often the only effective treatment; however, the treatment of malignant sacral tumors can be challenging, both because of the anatomy of the spinopelvic complex and the frequently large tumor size.

PURPOSE

We report a case of sacral chondrosarcoma that was successfully treated by total en bloc sacrectomy and reconstruction of the lumbosacral and pelvic ring using intraoperative extracorporeal irradiated autologous tumor-bearing sacrum.

STUDY DESIGN

A case report with 10 years follow-up.

METHODS

A 51-year-old man presented with right lower leg pain. Plain radiographs and computed tomography (CT) showed an osteolytic lesion at the sacrum that extended to the sacroiliac joint. Magnetic resonance imaging demonstrated that the tumor mass was localized from S1 to S2 with an epidural lesion at L5-S1 disc level. Histopathologic evaluation by open biopsy revealed that the lesion was chondrosarcoma. Total en bloc sacrectomy of the tumor-bearing sacrum was performed. The removed tumor-bearing sacrum was extracorporeally irradiated at 200 Gy during the operation and returned to the original position as a bone graft and fixed with instruments thereafter.

RESULTS

We needed two revision surgeries during the first 3 years because of the implant failures; however, 10 years after the initial surgery, CT revealed that the irradiated sacrum had remodeled into living bone and integrated with surrounding iliac bone without radiological evidence of tumor recurrence. The patient ambulates without any support and there was no clinical and radiological evidence of tumor recurrence.

CONCLUSIONS

The advantages of our method include the availability of high dose of radiation because of extracorporeal irradiation, excellent fit between graft and host bone, reduction of the dead space, no immunological rejection, no need for a bone bank, availability of the sacrum not only for the augmentation of the large defect but also for the scaffold for the other bone grafts. Our report is of only one case; however, we consider that it could be one option for the treatment of sacral malignant bone tumors, such as chondrosarcoma.

Prognostic value of histological response to chemotherapy in osteosarcoma patients receiving tumor-bearing frozen autograft

Background

A variety of surgical procedures are now available for tissue reconstruction after osteosarcoma excision, and an important prognostic factor is the evaluation of response to chemotherapy using histology. Although tumor-bearing autografts are useful tools for reconstruction, re-use of the primary tumor may make it difficult to assess the histological response to chemotherapy, since the entire tumor cannot be analyzed. Here, we analyzed the prognostic value of the histological response in the patients who received frozen tumor-bearing autografts for reconstruction.

Method

Retrospective analysis of the medical records of 51 patients with high-grade osteosarcoma of the extremities was performed. All patients received reconstruction using frozen tumor-bearing autografts. Tumor necrosis was evaluated in extraskeletal masses and cancellous bone.

Results

Five-year overall survival of patients with good and poor response to chemotherapy was 82.9% and 46.4%, respectively (P = 0.044), and 5-year event-free survival was 57.7% and 36.0%, respectively (P = 0.329). Multivariate analysis revealed that a poor histological response to chemotherapy was a significant prognostic factor for overall survival (P = 0.033).

Conclusion

Histological response is an important and reliable prognostic factor in patients undergoing reconstruction using frozen tumor-bearing autografts.

Evaluation of long-term outcomes of pasteurized autografts in limb salvage surgeries for bone and soft tissue sarcomas

BACKGROUND

Pasteurized autografts used in limb salvage operations for malignant musculoskeletal tumors have several advantages, including reduced disease transmission, economic efficiency, accessibility, and anatomical conformation. However, their use has been associated with bone absorption, fracture, and pseudarthrosis. Few studies exist which have assessed the long-term outcomes of pasteurized autografts. The purpose of this study was to investigate the clinical outcomes of patients treated with pasteurized autografts and to compare these outcomes across various graft types.

METHODS

A retrospective analysis of 46 patients treated with pasteurized autografts between 1992 and 2010 was conducted. The analysis included 22 intercalary bone grafts, 17 inlay grafts, 4 composite grafts, and 3 osteochondral grafts, with the mean follow-up period of 8.7 years (2-17 years).

RESULTS

The 10-year survival rate of the 46 pasteurized autograft cases analyzed was 93.5 %, and the average bone union time between host and pasteurized autogenous bone was 9.5 months. Infections were identified in 6 (13 %) patients, fractures in 7 (15 %) patients, non-union in 8 (17 %) patients, and bone absorption in 6 (13 %) patients. Inlay grafts were completely incorporated with the host bone at the follow-up period. Combination with a vascularized fibular graft significantly reduced the risk of non-union and bone absorption (p < 0.05 and p < 0.01, respectively), with an average functional score of 23.1/30 (83.8 %).

CONCLUSION

Our findings show that pasteurized bone grafts in combination with vascularized fibular grafts have improved outcomes and potential clinical indications.

Long-term results from use of pasteurized bone

BACKGROUND

Pasteurized bone (PB) is recycled bone. The pasteurization has a tumor cell-killing effect wit retention of initial strength. However, few reports have been published on its long-term course; thus, in this study, we evaluated the long-term course of use of PB and examined appropriate reconstruction methods.

PATIENTS AND METHODS

We reviewed 27 cases in which reconstructive surgery using PB was performed between 1990 and 2002. Of these, we excluded 12 fatal cases and 1 case in which follow-up was discontinued. Therefore, our final analysis consisted of 14 cases with an average follow-up period of 165 months. The reconstruction methods used were: osteoarticular graft in 6 cases, composite graft with prosthesis in 3 cases, intercalary graft in 1 case, and reconstruction using PB from the pelvis in 4 cases.

RESULTS

The PB survived in 7 of the 14 cases. Five and 10-year survival of the PB was 78.6 and 47.6%, respectively. Three of the 6 osteoarticular cases failed because of late-onset absorption or infection of the PB. For patients with composite graft or intercalary graft, long-term survival was achieved when small amounts of PB were used. For patients with pelvic grafts, long-term survival was achieved in a case of P1 pelvis, but large PB grafts on small bone-junction surfaces were not successful in the long term. On the basis of these results, we were able to achieve successful long-term results with small PB grafts on large bone-junction surfaces.

CONCLUSIONS

To prevent bone absorption and achieve long-term survival of PB, it is important to use a small PB graft and create a large surface area of contact with normal bone. These factors are advantageous to PB survival and to gaining limb function.

The healing process of intracorporeally and in situ devitalized distal femur by microwave in a dog model and its mechanical properties in vitro

Background

Limb-salvage surgery has been well recognized as a standard treatment and alternative to amputation for patients with malignant bone tumors. Various limb-sparing techniques have been developed including tumor prosthesis, allograft, autograft and graft-prosthesis composite. However, each of these methods has short- and long-term disadvantages such as nonunion, mechanical failures and poor limb function. The technique of intracorporeal devitalization of tumor-bearing bone segment in situ by microwave-induced hyperthermia after separating it from surrounding normal tissues with a safe margin is a promising limb-salvage method, which may avoid some shortcomings encountered by the above-mentioned conventional techniques. The purpose of this study is to assess the healing process and revitalization potential of the devitalized bone segment by this method in a dog model. In addition, the immediate effect of microwave on the biomechanical properties of bone tissue was also explored in an in vitro experiment.

Methods

We applied the microwave-induced hyperthermia to devitalize the distal femurs of dogs in situ. Using a monopole microwave antenna, we could produce a necrotic bone of nearly 20 mm in length in distal femur. Radiography, bone scintigraphy, microangiography, histology and functional evaluation were performed at 2 weeks and 1, 2, 3, 6, 9 and 12 months postoperatively to assess the healing process. In a biomechanical study, two kinds of bone specimens, 3 and 6 cm in length, were used for compression and three-point bending test respectively immediately after extracorporeally devitalized by microwave.

Findings

An in vivo study showed that intracorporeally and in situ devitalized bone segment by microwave had great revitalization potential. An in vitro study revealed that the initial mechanical strength of the extracorporeally devitalized bone specimen may not be affected by microwave.

Conclusion

Our results suggest that the intracorporeal microwave devitalization of tumor-bearing bone segment in situ may be a promising limb-salvage method.

Can bone scintigraphy predict the final outcome of pasteurized autografts?

OBJECTIVE

As pasteurization is becoming more widely used in limb salvage reconstruction, more study is required to understand about host-graft junction healing, graft revascularization and incorporation, and the incidence and type of complications among pasteurized autografts. This was mainly achieved by follow-up radiography. We aimed to clarify whether Tc99m bone scanning can be considered a reliable method in determining these three parameters.

MATERIALS AND METHODS

Twenty-seven osteosarcoma patients with pasteurized autograft reconstructions were retrospectively reviewed using available scintigraphic and radiographic follow-up every 6 months postoperatively for 36 months. Follow-up of the unhealed cases was continued for the maximum follow-up period available for each case beyond the original study period, ranging from 1 to 15 months. Tc99m uptake was classified as cold, faint, moderate and high uptake. Junction healing was classified as none, partial and complete healing.

RESULTS

Seventy percent of junctions united with a mean of 22 months. Ninety to 100% of junctions showed increased uptake (high or moderate) at one time of the study regardless of final outcome. 85% of the pasteurized grafts showed the characteristic "tramline appearance". Four grafts (15%) were complicated: pseudoarthrosis and implant failure (1), fractured plate (1), intramedullary nail (IMN) fracture (1), and prosthesis stem loosening in the host bone (1), with underlying unhealed junctions in all cases.

CONCLUSION

Bone scanning can determine the stages of the graft's rim revascularization and incorporation; however, it cannot detect or predict junction healing or occurrence of complications. Supplementary treatment of unhealed junctions showing either decreased junctional uptake or graft quiescence may be warranted. Otherwise, detection of distant metastasis and early local recurrence remains the main application of Tc99m scanning in the management of bone sarcomas.

Establishment of an animal model of a pasteurized bone graft, with a preliminary analysis of muscle coverage or FGF-2 administration to the graft

Background

Pasteurized bone grafting is used following the excision of a bone tumor for the purpose of eliminating neoplastic cells while preserving bone-inducing ability. In the hopes of guaranteeing the most favourable results, the establishment of an animal model has been urgently awaited. In the course of establishing such a model, we made a preliminary examination of the effect of muscle coverage or fibroblast growth factor 2 (FGF-2) administration radiographically.

Methods

Forty pasteurized intercalary bone grafts of the Wistar rat femur treated at 60°C for 30 min were reimplanted and stabilized with an intramedullary nail (1.1 mm in diameter). Some grafts were not covered by muscle after the implantation, so that they could act as a clinical model for wide resection, and/or these were soaked with FGF-2 solution prior to implantation. The grafts were then divided into 3 groups, comprising 12 grafts with muscle-covering but without FGF-2 (MC+; FGF2-), 12 grafts without muscle-covering and without FGF-2 (MC-; FGF2-) and 16 grafts without muscle covering but with FGF-2 (MC-; FGF2+).

Results

At 2 weeks after grafting, the pasteurized bone model seemed to be successful in terms of eliminating living cells, including osteocytes. At 4 weeks after grafting, partial bone incorporation was observed in half the (MC+; FGF2-) cases and in half the (MC-; FGF2+) cases, but not in any of the (MC-; FGF2-) cases. At 12 weeks after grafting, bone incorporation was seen in 3 out of 4 in the (MC+; FGF2-) group (3/4: 75%) and in 3 out of 8 in the (MC-; FGF2+) group (3/8: 38%). However, most of the grafted bones without FGF-2 were absorbed in all the cases, massively, regardless of whether there had been muscle-covering (MC+; FGF2-; 4/4: 100%) or no muscle-covering (MC-; FGF2-; 4/4: 100%), while bone absorption was noted at a lower frequency (2/8: 25%) and to a lower degree in the (MC-; FGF2+) group.

Conclusion

In conclusion, we have established an animal pasteurized bone graft model in rats. Pasteurized bone was able to maintain bone induction ability. Despite the low number of cases in each group, the results of each group suggest that muscle-covering has an effect on bone incorporation, but that it is not able to prevent bone absorption to the pasteurized bone. However, an application of FGF-2 may have a positive effect on bone incorporation and may be able to prevent bone absorption of the graft in cases of pasteurized bone graft.

Technetium-99 m-MDP scintigraphy and long-term follow-up of musculo-skeletal sarcoma reconstructed with pasteurized autologous bone graft

INTRODUCTION

Local bone tumor excision followed by pasteurization and reimplantation is a unique technique of reconstruction for sarcoma patients. The long-term scintigraphic findings of pasteurized bone grafts in relation to clinical patients' data were reviewed retrospectively.

PATIENTS

Twenty-two sarcoma patients (mean age, 24 years) done between April 2000 and January 2004 constituted the material of this study. One hundred and fifty-two 99 m TC-methylene diphosphonate (MDP) whole-body scans were reviewed. Initially, all autografts appeared as photon deficient areas. Diffusely increased bone uptake was present at the osteotomy sites within 4-6 months after surgery, the uptake of the grafted pasteurized bone was detected in 17 patients from about 6 months after surgery.

RESULTS

Of 22 patients, 11 (50%) showed higher uptake than the normal bone, 6 (27%) had uptake similar to the normal bone, while 5 (23%) had less uptake than the normal bone. Radiologically, 15 patients (68%) showed complete incorporation of graft and 5 patients (23%) had partial incorporation. Oncologically, 16 patients are disease free, while 6 died of disease. No local recurrence was detected at a mean of 59 months, while fracture (13.6%) eventually healed with bone grafting and revision of internal fixation, graft collapse (9%) (needed revision arthroplasty) and infection (9%), one cured and one converted to rotationplasty, were the major complications encountered. Significantly more mechanical complications were seen when tracer uptake suggestive of revascularization occurred; thus, revascularization and partial bone ingrowth are not sufficient conditions for lower mechanical complication rate.

CONCLUSION

The method of pasteurization of bone is a useful option for reconstruction after resection of malignant bone tumors.

Pasteurized autograft-prosthesis composite for distal femoral osteosarcoma

BACKGROUND

We examined the survivorship and functional outcome of the pasteurized autograft-prosthesis composite for distal femoral osteosarcoma. We also evaluated complications including nonunion, loosening, bony resorption, infection, and fracture.

METHODS

We retrospectively reviewed 15 distal femoral osteosarcoma patients who underwent reconstructions using pasteurized autograft-prosthesis composite between 1993 and 2003.

RESULTS

No patient required graft removal during a minimum follow-up of 35 months (average 56 months; range 35-78 months). The average Musculoskeletal Tumor Society System (MTSS) functional score was 86%. Nonunion developed in five patients, and three of them subsequently showed loosening of the stem. No patient experienced infection or fracture.

CONCLUSIONS

Our data suggest that the pasteurized autograft-prosthesis composite could be an easily accessible alternative for the reconstruction of large skeletal defects in the distal femur because of the satisfactory functional outcome with a low rate of ultimate failure and complications in this study.

The use of pasteurized autologous grafts for periacetabular reconstruction

Reconstruction after periacetabular resection is a challenge. We asked whether the use of pasteurized autologous grafts would provide satisfactory results regarding patient survival, local recurrence, and metastasis, and graft union and functional outcome. We retrospectively reviewed 11 patients having such grafts with a minimum followup of 12 months (mean, 40 months; range, 12-116 months). All patients underwent periacetabular (Type II) resection of malignant periacetabular tumors. The resected bone was treated in saline at 65 degrees C for 30 minutes and reimplanted into the host bone with internal fixation. Total hip arthroplasty was performed in all patients. Local recurrence occurred in two of nine patients with primary sarcoma. Ten grafts survived at the last followup. Union of the resected bone with the host bone was achieved in eight of the 11 patients at an average of 12 months. The overall functional rating was 61% according to the Musculoskeletal Tumor Society System, with better results in the patients with primary tumors. Graft fracture (one patient) and infection (one patient) were the major complications. Our data suggest the use of pasteurization may be a reasonable option for reconstruction after resection of malignant periacetabular tumors.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Pasteurized intercalary autogenous bone graft combined with vascularized fibula

The optimal reconstruction procedure after wide resection of bone tumors is debatable. We reviewed pasteurized intercalary autogenous bone graft combined with a vascularized fibula graft in 15 patients with malignant bone tumors, and assessed whether this procedure would improve bone union and function. The mean duration until bone union of the pasteurized autogenous bone was 13.5 months and duration until union of the vascularized fibula was 7.7 months. Complete bone union between the pasteurized autogenous bone and the vascularized fibula eventually was achieved in 13 patients (86.7%). In the remaining two patients, fibula union was achieved but union of the pasteurized autogenous bone was not attributable to infection. Postoperative complications included two fractures and two infections. Three patients with delayed union eventually achieved bone union using an autogenous cancellous bone graft. The mean Musculoskeletal Tumor Society score was 80.6% and it was comparable to scores from other procedures. Our results suggest a pasteurized autogenous bone graft combined with a vascularized fibula graft can be a useful reconstruction method in selected patients with large bone defects after wide resection of malignant bone tumors.

Reconstruction using an autograft containing tumour treated by liquid nitrogen

We describe a method of reconstruction using tumour-bearing autograft treated by liquid nitrogen in 28 patients. The operative technique consisted of en bloc excision of the tumour, removal of soft tissue, curettage of the tumour, drilling and preparation for internal fixation or prosthetic replacement before incubation for 20 minutes in liquid nitrogen, thawing at room temperature for 15 minutes, thawing in distilled water for ten minutes, and internal fixation with an intramedullary nail, plate or composite use of prosthetic replacement. Bone graft or cement was used to augment bone strength when necessary. The limb function was rated as excellent in 20 patients (71.4%), good in three (10.7%), fair in three (10.7%), and poor in two (7.1%). At the final follow-up six patients had died at a mean of 19.8 months after the operation, while 21 remained free from disease with a mean follow-up of 28.1 months (10 to 54). One patient is alive with disease. Bony union was seen at a mean of 6.7 months after the operation in 26 patients. Complications were encountered in seven patients, including three deep infections, two fractures, and two local recurrences. All were managed successfully. Our results suggest that this is a simple and effective method of biological reconstruction.

Pasteurized autologous bone graft in surgery for bone and soft tissue sarcoma

For skeletal reconstruction in surgery for bone tumors, pasteurization of bone has been used with favorable results over autoclaving or boiling. Twenty-three patients with primary malignant bone tumors and two patients with soft tissue sarcoma invading bone reconstruction surgery with pasteurized autologous bone graft comprised the study group. There were 16 females and nine males, between 7 and 77 years of age who were followed up for at least 3 years (mean, 52 months). The International Society of Limb Salvage graft evaluation method was used for evaluation of the radiographs. Fifteen patients (60%) had complete incorporation of the graft and eight patients (32%) had partial incorporation. Viability of the grafts was evaluated by bone scintigraphy. Of 22 patients evaluated, uptake was detected in 17 patients from approximately 6 months postoperatively after which it increased gradually. The functional results were assessed by the system of the Musculoskeletal Tumor Society, and the mean functional rating was 86%. Eighteen patients have been disease-free and seven have died of disease. Fracture (12%) and infection (20%) were the main complications. No local recurrence was detected. These results indicate that pasteurization of bone may be a useful option for reconstruction after resection of malignant bone tumors. The advantages of extracorporeal pasteurization include convenience of use, avoidance of intraspecies infection and allogenic reactions, and satisfactory bone remodeling.

Effects of liquid nitrogen treatment on the proliferation of osteosarcoma and the biomechanical properties of normal bone

To overcome problems of autografts for reconstruction in the presence of malignant bone and soft tissue tumors, we devised a method for treating autografts that utilizes the hypothermic effect of liquid nitrogen. We measured temperature changes inside the bone at each condition and established a one-cycle liquid nitrogen protocol that included 20 min in liquid nitrogen, 15 min in room air, and 15 min in physiological saline. The proliferation potential of the tumor cells treated with the liquid nitrogen method was examined by means of bromodeoxyuridine (BrdU) immunostaining. Tumor proliferation potential in vivo was examined in nude mice. Based on the results we concluded that the tumor cells died out as a result of the liquid nitrogen method. Regarding compression strength there was no significant difference between intact bone and liquid nitrogen-treated bone, whereas the strength of the autoclaved bone was decreased. Scanning electron microscopic examination of the fracture surface of the autoclaved bone after the compression test showed an irregular, uneven surface, whereas that of the liquid nitrogen-treated bone was smooth and fine-grained. This might be one of the reasons for the discrepancy in compression strength.

Reconstruction with autologous pasteurized whole knee joint I: experimental study in a rabbit model

Hyperthermia-treated bone has been used for skeletal reconstruction after resection of malignant bone tumors, and more favorable results have been seen after pasteurization than after autoclaving or boiling. Pasteurization destroys malignant cells while preserving the bone-inducing property. All previous experimental models have studied replantation of bone segments, but reconstruction of joints is more important clinically. We studied the effects of extracorporeal hyperthermia on the reintegration of autologous whole knee joint grafts over a period of 16 weeks in a rabbit model. The whole knee joint was resected from 32 animals, heat-treated at 65 degrees C for 30 min, and replanted. In the control group, resection and replantation were performed without heat treatment. Reintegration was assessed by macroscopic analysis, histology, histochemistry, and radiography. Reintegration of the pasteurized group showed excellent remodeling during the 16 weeks, similar to the control groups. Responses to the pasteurization and the subsequent reintegration of cartilage, menisci, and ligaments were similar at 4, 8, 12, and 16 weeks with no significant difference between the two groups, although cartilage degradation seemed to occur earlier in the study group than in the control group. These results suggest that pasteurization may be superior to other cell-lethal treatments for autotransplantation of the whole joint currently available.

Radiographic analysis of pasteurized autologous bone graft

OBJECTIVE

Local malignant bone tumor excision followed by pasteurization and subsequent reimplantation is a unique technique for reconstruction after resection of primary bone sarcomas. The purpose of this investigation was to assess the normal and abnormal long-term radiographic findings of intercalary and osteo-chondral pasteurized bone graft/implant composite.

DESIGN AND PATIENTS

The long-term radiographic findings of pasteurized bone grafts used in reconstruction after resection of bone and soft tissue sarcomas in relation to patients' clinical data were reviewed retrospectively. Thirty-one patients (18 females, 13 males; age range 7-77 years, mean 30 years) who underwent surgery between April 1990 and January 1997 at the authors' institute constituted the material of this study. They were followed up for at least 3 years or until the patient's death (mean 69 months). The International Society of Limb Salvage graft evaluation method that assesses the fusion, resorption, fracture, graft shortening, fixation, subluxation, joint narrowing and subchondral bone was used for evaluation of the radiographs.

RESULTS AND CONCLUSIONS

Twenty-one patients (68%) showed complete incorporation of graft and eight patients (26%) had partial incorporation. The overall radiographic evaluation rate was 81%. Fracture (10%) and infection (16%) were the main complications. No local recurrence was detected. These results indicate that pasteurization of bone is a useful option for reconstruction after resection of malignant bone tumors.

Histological and radiological analysis of autoclaved bone 2 years after extirpation

We examined grafted distal femoral autoclaved bone radiologically and histologically 24 months after surgery. The patient was a 16-year-old boy with osteoblastic-type osteosarcoma in the distal part of the left femur. The patient received pre- and postoperative chemotherapy and underwent limb reconstruction surgery using an autoclaved autograft. He was forced to undergo hip disarticulation because of local recurrence in the soft tissue. Radiologically and histologically, we were able to detect newly formed bone at the site of the distal junction and surrounding the autoclaved autograft, although most of the autoclaved bone remained without substitution even 24 months after implantation. The layer of newly formed bone surrounding the autoclaved autograft was so thin that it seemed to be ineffective for weight-bearing. Drilling into the autoclaved autograft appeared to promote little bone regeneration inside the autoclaved autograft. A bone scintigram showed newly formed bone around the autoclaved autograft, but the scan tended to exaggerate such bone formation beyond that actually confirmed by histological examination. We should be careful when applying autoclaved bone for weight-bearing parts.