Extracorporeal irradiated autogenous osteochondral graft

Patella cryo-free technique with recycled frozen autograft reconstruction preserves extensor mechanism for proximal tibial malignancy

BACKGROUNDS

We designed a patella cryo-free method to protect patella from cryoinjury during recycled frozen bone-prosthesis-composite reconstruction for proximal tibial malignancy. This study aimed to use animal model to ensure safety and efficacy of this method and reported our clinical outcomes.

METHODS

Six swine proximal tibias along with patella and patellar tendon were harvested and dived into group A (n = 3, traditional patella freezing) and group B (n = 3, patella cryo-free). Temperature curve measurement, histological analysis, and TUNEL assay were performed in both groups. Clinically, we retrospectively reviewed 23 patients with proximal tibia malignant bone tumor (13: traditional patella freezing method; 10: patella cryo-free method). The clinical and functional outcomes were reported and compared in both groups.

RESULTS

Temperature curve of the group B showed that ideal therapeutic temperature (<-60°C) required to kill tumor cells can be achieved in the proximal tibia while the innocent patella can be kept in room temperature at all time. Histological analysis showed better preservation of the cartilage tissue in patella of group B. TUNEL assay showed significantly more apoptotic cells in the frozen tibia of both groups and frozen patella of group A. When reviewing our clinical results, less complication of the patella as well as better functional preservation were found in patients subjecting to patella cryo-free method. No local recurrence was observed in either group.

CONCLUSION

Patellar cryo-free technique could protect patella from cryoinjury during freezing and therefore preserve more extensor functions for patients with proximal tibial malignant bone tumors.

Lengthening and deformity correction in vascularized fibular autograft for a patient with Ewing sarcoma

We report the case of a pediatric patient with Ewing's sarcoma of the tibia treated with vascularized fibular autograft where the resulting limb deformity and leg length discrepancy (LLD) were corrected using Ilizarov external fixator. A 14-year-old girl presented to our outpatient clinic with a deformity of the right proximal and distal tibia and an 11.7 cm of LLD after tumor reconstruction surgery. Deformity correction and limb lengthening were simultaneously performed using double corticotomy on the right proximal and distal tibia. One year postoperatively, the union of the right proximal tibia had progressed, but nonunion was observed at the right distal corticotomy site. To address this, osteosynthesis with tricortical iliac bone allograft was performed after the removal of the Ilizarov external fixator. After 6 months, the union of the distal tibia was confirmed, and the varus deformity of proximal and distal tibia improved. The LLD was also decreased, but the left lower limb was still longer by 3 cm. This report shows that vascularized fibular autografts can potentially be used for the gradual correction of LLD and deformities. However, for the treatment of multiple deformities in bones previously reconstructed with vascularized fibular graft, the possibility of impaired bone forming potential of the fibular graft should be considered.

Case report on metastatic pelvic bone tumor treated with frozen autograft by liquid nitrogen

INTRODUCTION AND IMPORTANCE

Frozen autograft recycling has been used for biological reconstruction of bone defects following tumor excision, more commonly in extremities. We report on the histological outcome of a pelvic recycled frozen autograft.

CASE PRESENTATION

We investigated the pelvic frozen autograft removed in 2 years and 8 months after surgery because of soft tissue recurrence in pelvic floor. The autograft bone showed no evidence of revitalization and was non-viable with patchy inflammation, and no residual tumor. There was only fibrous union but the autograft bone remained mechanically stable.

CLINICAL DISCUSSION

We confirmed the clearance of tumor cells with the treatment with liquid nitrogen. The union at the host-graft junction might be affected by the previous radiotherapy, the presence of infection, the small contact area limited by the anatomy, and the inadequate compression across the osteotomy interface with the fixation.

CONCLUSION

Frozen autograft treated by liquid nitrogen can be used safely for biological reconstructions after pelvic tumor excision.

Reconstruction of knee extensor with patellar tendon autograft following intraoperative radiotherapy

BACKGROUND

Patellar tendon autograft after intraoperative extracorporeal radiotherapy has been used for reconstruction of the extensor mechanism following limb-sparing wide tumor resection around the knee. The purpose of this study was to determine the clinical outcome of this reconstruction technique.

METHODS

We retrospectively reviewed six consecutive patients with peripatellar tendon and proximal tibial sarcoma who underwent reconstruction of the knee extensor mechanism. The resection area was planned to be contained with the patellar tendon in order to obtain a wide margin. First, the patella was osteotomized at the midline, and the inferior half of patella, patellar tendon, and tibial tuberosity were excised en bloc. The resected segments were devitalized with intraoperative extracorporeal radiotherapy and reimplanted into the original site. A follow-up evaluation included an assessment of the range of motion, extensor lag, the International Society of Limb Salvage score, and complications.

RESULTS

Six patients were followed up for 121-270 months. One patient underwent an additional reconstruction with total knee arthroplasty due to a collapse of the tibial subchondral bone. A supracondylar fracture of the femur occurred in two patients, and a delayed union of the osteosynthesis site of the tibial shaft was observed in one patient. At the latest follow up, extensor lag had a median of five degrees, and International Society of Limb Salvage scores had a median of 83%. No local recurrence or rupture of the patellar tendon was observed.

CONCLUSIONS

Reconstruction of the knee extensor mechanism using a patellar tendon treated with intraoperative radiotherapy is a reliable and successful method.

Long-term outcomes of an extracorporeal irradiated autograft for limb salvage operations in musculoskeletal tumours

Aims

We analyzed the long-term outcomes of patients observed over ten years after resection en bloc and reconstruction with extracorporeal irradiated autografts

Patients and Methods

This retrospective study included 27 patients who underwent resection en bloc and reimplantation of an extracorporeal irradiated autograft. The mean patient age and follow-up period were 31.7 years (9 to 59) and 16.6 years (10.3 to 24.3), respectively. The most common diagnosis was osteosarcoma (n = 10), followed by chondrosarcoma (n = 6). The femur (n = 13) was the most frequently involved site, followed by the tibia (n = 7). There were inlay grafts in five patients, intercalary grafts in 15 patients, and osteoarticular grafts in seven patients. Functional outcome was evaluated with the Musculoskeletal Tumor Society (MSTS) scoring system.

Results

There were no recurrences in the irradiated autograft and the autograft survived in 24 patients (88.9%). Major complications included nonunion (n = 9), subchondral bone collapse (n = 4), and deep infection (n = 4). Although 34 revision procedures were performed, 25 (73.5%) and four (11.8%) of these were performed less than five years and ten years after the initial surgery, respectively. The mean MSTS score at the last follow-up was 84.3% (33% to 100%).

Conclusion

Considering long-term outcomes, extracorporeal irradiated autograft is an effective method of reconstruction for malignant musculoskeletal tumours Cite this article: Bone Joint J 2019;101-B:1151–1159

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.

Extracorporeal radiation and reimplantation: a safe and viable option for reconstruction after sacral tumor resection?

Primary tumors of the sacrum are difficult to manage, as they often require morbid resections and complex reconstructions. In the case of tumors such as chordoma or chondrosarcoma, aggressive resections are often required to achieve appropriate margins (extending disease-free survival), followed by complex reconstructions. These reconstructions are aimed at restoring the pelvic ring and have traditionally resulted in a lumbosacral construct that utilizes structural allograft/autograft bone (fibula most commonly used) and more recently, reconstruction with 3D-printed custom sacral prostheses. While there are no reports of anatomical reconstruction using sacral allografts, extracorporeal radiation therapy (ECRT) and reimplantation provides a size and shape-matched irradiated autograft which avoids the cultural stigma, structural strength and graft-host concerns associated with allografts, as well as the high costs and time to production associated with custom 3D-printed implants. Here we present an illustrative case with technical notes, outlining the steps used at our center for ECRT. While early results with ECRT in the sacrum are promising, future larger studies should be carried out to help detect differences that may exist in long-term complications.

Intraoperative Extracorporeal Irradiation and Frozen Treatment on Tumor-bearing Autografts Show Equivalent Outcomes for Biologic Reconstruction

BACKGROUND

Immediately recycling the resected bone segment in a biologic limb salvage reconstruction is an option after wide resection of bone. Intraoperative extracorporeal irradiation and freezing are the two major tumor-killing techniques applied on the fresh tumor-bearing autografts. However, graft-derived tumor recurrence and complications are concerns affecting graft survival.

QUESTIONS/PURPOSES

We therefore asked: (1) Is there a difference in the proportion of patients achieving union by 18 months after surgery between the groups with extracorporeal-irradiated autografts and frozen-treated autografts? (2) Is there any difference in the frequency of graft-related complications for patients receiving either an extracorporeal-irradiated or a frozen-treated autograft? (3) Is there a difference between the techniques in terms of graft-derived recurrence? (4) Are there differences in failure-free grafts, and limb and overall survivorship between autografts treated by extracorporeal irradiation or by freezing?

METHODS

During the study period we treated a total of 333 patients with high-grade osteosarcoma. One hundred sixty-nine patients were excluded. Overall, 79 of the enrolled 164 patients received recycled autografts treated with extracorporeal irradiation whereas the other 85 received frozen-treated autografts. The mean followup was 82 ± 54 months for the extracorporeal irradiation group and 70 ± 25 months for the frozen autograft group, and one patient was lost to followup. Complications and graft failure (revision required for primary graft removal) were characterized by adapting the International Society of Limb Society (ISOLS) system modified for inclusion of biologic and expandable reconstruction. The primary study endpoints were the proportion of patients in each group who achieved radiographic union, and had an ISOLS grade of fair or good host graft fusion at 6, 9, 12, and 18 months after surgery. Five-year survival data for graft failure and limb amputation were analyzed by a cumulative incidence function regression model whereas the Kaplan-Meier function was used to test the 5-year overall survival rate between the two techniques.

RESULTS

With the numbers available, no differences were found in the accumulated proportion of patients achieving union between the groups at 6, 9, 12, and 18 months. Radiographic evaluation did not show differences in the average scores of compared criteria. However in the subchondral bone subcriterion, more patients receiving frozen-treated autografts had higher scores (p = 0.03). Complications leading to a second surgery were not different between extracorporeal irradiation and frozen autografts in aspects of soft tissue failure (Type 1B), nonunion (Type 2B), structural failure (Type 3A and Type 3B), or infection (Type 4A and Type 4B). No graft-originating tumor recurrence was found and there was no difference in Type 5A tumor progression originating from soft tissue in the groups (odds ratio, 0.8; 95% CI, 0.3-2.1; p = 0.7). Neither group showed a difference in the cumulative incidence for graft failure and limb amputation. Five-year overall survival rates were 83% and 84% (p = 0.69) for extracorporeal-irradiated and frozen autografts respectively. A decrease in survivorship was seen at 50 to 100 months after surgery for the extracorporeal irradiation group.

CONCLUSION

We segregated the ISOLS criteria evaluating the graft-mediated tumor progression into host- or graft-derived complications (Types 5B and 5C) in this study. With the available data, there was no difference in the incidence of tumor recurrence derived from irradiation- or frozen-treated autografts. Ongoing evaluations comparing 10-year survivorship for both groups will be helpful to elucidate the possible difference found after 100 months.

LEVEL OF EVIDENCE LEVEL

III, therapeutic study.

The mechanical effects of extracorporeal irradiation on bone

Extracorporeal irradiation of an excised tumour-bearing segment of bone followed by its re-implantation is a technique used in bone sarcoma surgery for limb salvage when the bone is of reasonable quality. There is no agreement among previous studies about the dose of irradiation to be given: up to 300 Gy have been used. We investigated the influence of extracorporeal irradiation on the elastic and viscoelastic properties of bone. Bone was harvested from mature cattle and subdivided into 13 groups: 12 were exposed to increasing levels of irradiation: one was not and was used as a control. The specimens, once irradiated, underwent mechanical testing in saline at 37°C. The mechanical properties of each group, including Young's modulus, storage modulus and loss modulus, were determined experimentally and compared with the control group. There were insignificant changes in all of these mechanical properties with an increasing level of irradiation. We conclude that the overall mechanical effect of high levels of extracorporeal irradiation (300 Gy) on bone is negligible. Consequently the dose can be maximised to reduce the risk of local tumour recurrence.

Intraoperative extracorporeal autogenous irradiated tendon grafts for functional limb salvage surgery of soft tissue sarcomas of the wrist and hand

BACKGROUND

In patients with soft tissue sarcoma of the wrist and hand, limb salvage operation is extremely challenging for surgeons in attempting a complete tumor resection with negative surgical margins. In this study, we report four patients with soft tissue sarcoma of the wrist and hand treated by limb salvage operation with intraoperative extracorporeal autogenous irradiated tendon grafts.

METHODS

The patients were all male, and the mean age at the time of surgery was 45 years. Histological diagnoses included clear cell sarcoma in two patients, synovial sarcoma in one, and angiosarcoma in one. All four patients had high grade tumors, wherein three had American Joint Committee on Cancer (AJCC) stage III disease and one with AJCC stage IV disease. The tumors were resected en bloc with involved tendons. The tendons were isolated from the resected tissues, irradiated ex vivo, and re-implanted into the host tendons. In one patient, the bone was resected additionally because of tumor invasion to the bone. Hand function was evaluated using Musculoskeletal Tumor Society (MSTS) rating system.

RESULTS

Of the four patients, three died of distant metastatic disease. The remaining patient lives and remains disease-free. The mean follow-up period was 33 months. One patient had local recurrence outside the irradiated graft at 20 months after surgery. The functional rating was 22. Lower scores were seen in patients with reconstruction of flexor tendons than extensor tendons.

CONCLUSIONS

Limb salvage operation with intraoperative extracorporeal autogenous irradiated tendon grafts is an acceptable method in selected patients with soft tissue sarcoma of the wrist and hand.

Saving a Child's Elbow Joint: A Novel Reconstruction for a Tumour of the Distal Humerus

Reconstruction after wide resection of a malignant bone tumor can be obtained using several techniques such as the use of prostheses, allograft, autograft, or combined procedure. We describe a 12-year-old girl with parosteal osteosarcoma of the distal right humerus treated by en bloc resection, intraoperative extracorporeal irradiation, and implantation. We inserted a nonvascularised fibular autograft through the middle of irradiated graft to obtain a greater stability. We have not recorded any complication associated with this technique such as nonunion, pathological fracture, infection, and bone necrosis and we obtained an excellent functional result. 10 years after surgery, the patient had no recurrence. Extracorporeal irradiation and reimplantation is a valid and inexpensive technique for the treatment of bone tumors when there is reasonable residual bone stock. With this procedure we have a precise fit being the patient's own bone. In this way we avoid all the problems related to the adaptation of the shape and size.

Improved repair of bone defects with prevascularized tissue-engineered bones constructed in a perfusion bioreactor

Vascularization of tissue-engineered bones is critical to achieving satisfactory repair of bone defects. The authors investigated the use of prevascularized tissue-engineered bone for repairing bone defects. The new bone was greater in the prevascularized group than in the non-vascularized group, indicating that prevascularized tissue-engineered bone improves the repair of bone defects. [Orthopedics. 2014; 37(10):685-690.].

Recycling of extracorporeally irradiated autograft for malignant bone tumors: long-term follow-up

This study was conducted to evaluate the long-term oncological and functional outcomes. Forty-two patients (29 men and 13 women) with primary malignant bone tumors were included in this study. The procedure consisted of wide en bloc resection, clearing the extraosseous soft tissue and medullary content, extracorporeal irradiation with a single dose of 50 Gy using linear accelerator, and reimplantation using suitable fixation devices. The mean survivor follow-up was 54 months (24-174 months). There were 32 (76.2%) patients continuously disease free, 7 (16.7%) died of disease, and 3 (7.1%) alive with disease. Local recurrence was encountered in 4 (9.5%) patients. Nonunion occurred at 3 (6.4%) osteotomy sites. Deep infection developed in 4 (9.5%) cases. There were 13 patients rated excellent, 17 good, 10 fair, and 2 failures according to the Mankin scoring system. The mean ratings of the Musculoskeletal Tumor Society score and the Toronto Extremity Salvage Score were 77 and 81, respectively. The long-term oncological and functional results are encouraging and suggest that extracorporeal irradiation and reimplantation can be a long-lasting biological reconstructive technique in properly selected patients.

Pasteurization of bone for tumour eradication prior to reimplantation - an in vitro & pre-clinical efficacy study

BACKGROUND & OBJECTIVES

In current era of limb-salvage therapy, pasteurization of bone sarcomas is receiving growing attention as a potential extracorporeal treatment and cost-effective alternative to allografts and radiation before surgical reimplantation. Detailed in vitro and in vivo pre-clinical study to evaluate efficacy of pasteurization to eradicate malignant cells has not been reported yet. The present study was carried out to assess the efficacy of pasteurization to kill tumour cells both in vitro and in vivo.

METHODS

Surgically resected specimens of osteosarcomas (n=4) were cut into equal halves and one section was pasteurized by heating at 60°C to 65°C for 40 min. Paired samples before and after pasteurization were studied in vitro for DNA ploidy, evaluation of histological change and elimination of mitotic activity. These tissues were transplanted in immune-deficient NOD-SCID mice to evaluate effect on tumour-generating ability, presence of human nuclei, osteopontin and cytokine/chemokines released in tumour-transplanted mice.

RESULTS

Non-pasteurized tumour samples had viable tumour cells which exhibited significant growth in culture, increased proliferative ability and clonogenic potential while respective pasteurized tumour tissues did not grow in culture and did not exhibit clonogenicity. Flow cytometry revealed that propidium iodide positive dead cells increased significantly (P< 0.01) post pasteurization. Seven of 12 non-pasteurized tumour transplanted mice demonstrated tumour-forming ability as against 0 of 12 in pasteurized tumour transplanted mice. Solid tumour xenografts exhibited strong expression of anti-human nuclei and osteopontin by immunohistochemistry as well as secretary human interluekin-6 (IL-6) while pasteurized mice failed to express these markers.

INTERPRETATION & CONCLUSIONS

This study has provided a basis to establish pasteurization as being efficacious in ensuring tumour eradication from resected bone tumour specimens. Pasteurized tumour bearing bone can thus safely be used to reconstruct large defects after tumour resection.

The outcome of the treatment of diaphyseal primary bone sarcoma by resection, irradiation and re-implantation of the host bone

We analysed the outcome of patients with primary non-metastatic diaphyseal sarcomas who had en bloc resection with preservation of the adjoining joints and reconstruction with re-implantation of sterilised tumour bone after extracorporeal radiation (50 Gy). Between March 2005 and September 2009, 32 patients (16 Ewing’s sarcoma and 16 osteogenic sarcoma) with a mean age of 15 years (2 to 35) underwent this procedure. The femur was the most common site in 17 patients, followed by the tibia in 11, humerus in three and ulna in one. The mean resected length of bone was 19 cm (10 to 26). A total of 31 patients were available at a mean follow-up of 34 months (12 to 74). The mean time to union for all osteotomy sites was 7.3 months (3 to 28): metaphyseal osteotomy sites united quicker than diaphyseal osteotomy sites (5.8 months (3 to 10) versus 9.5 months (4 to 28)). There were three local recurrences, all in soft-tissue away from irradiated graft. At the time of final follow-up, 19 patients were free of disease, one was alive with disease and 11 had died of disease. The mean Musculoskeletal Tumor Society Score for 29 patients evaluated at the last follow-up was 26 (9 to 30).

Extracorporeal irradiation is an oncologically safe and inexpensive technique for limb salvage in diaphyseal sarcomas and has good functional results.

A preliminary evaluation of limb salvage surgery for osteosarcoma around knee joint

Objective

To evaluate the effectiveness and drawbacks of diversified procedures of limb salvage surgery (LSS), providing a reference of rational surgical criterion of LSS.

Methods

Fifty eight patients with stage IIB extremity osteosarcoma around knee joint area between 1992 and 2002 were studied retrospectively. Among them, 43 patients were treated by LSS followed by reconstruction. Reconstruction approaches included re-implantation of irradiation-devitalized tumor bone (n = 12), autoclaving-devitalized tumor bone (n = 8), prosthetic replacement (n = 11), allograft transplantation (n = 8) and vascularized fibula autograft implantation (n = 4). Amputations were performed in 15 patients. Patients were followed up for 6–16 years.

Results

There were no significant difference between LSS and amputation groups regarding disease free survival and local recurrence rates. The actuarial 5-year continuous disease free survival and local recurrence rate were 30.0% and 25.0% in patients of devitalized LSS group, whereas those were 56.5% and 8.7% in patients of non-devitalized reconstruction group. The complication rate was significantly higher in LSS group compared to amputation group (P = 0.003).

Conclusion

LSS with non-devitalized procedures is the optimal treatment for osteosarcoma around knee joint area. Prosthesis implantation is the preferred option for bone reconstruction following LSS. Prevention and treatment of post-operative complications should be paid more attention to get good long-term outcomes of surgery.

Limb salvage operation using intraoperative extracorporeal autogenous irradiated bone and tendon graft for myxoid liposarcoma on dorsum of foot

Foot and ankle sarcomas are conventionally treated with amputation. In this article, we report a case of myxoid liposarcoma on the dorsum of the foot treated by limb salvage operation with intraoperative extracorporeal autogenous irradiated bone and tendon grafts. The patient was a 76-year-old woman with a soft tissue tumor beneath the extensor tendons with attachment to the tarsal and metatarsal bones. The histological diagnosis was myxoid liposarcoma. Wide margin was achieved by splitting the tarsal and metatarsal bones into dorsal and plantar parts. The dorsal part of the bones and tendons was isolated from the resected material, irradiated ex-vivo and re-implanted into the host's bones and tendons. No local recurrence was detected around the irradiated bones and tendons during the follow-up at 36 months. The functional rating was 74% according to the ISOLS rating system. This method may be a better procedure for limb salvage operation of sarcomas on the dorsum of the foot.

Which is the best method of sterilization of tumour bone for reimplantation? A biomechanical and histopathological study

Introduction

Sterilization and re-usage of tumour bone for reconstruction after tumour resection is now gaining popularity in the East. This recycle tumour bone needs to be sterilized in order to eradicate the tumour cells before re-implantation for limb salvage procedures. The effect of some of these treatments on the integrity and sterility of the bone after treatment has been published but there has yet been a direct comparison between the various methods of sterilization to determine the one method that gives the best tumour kill without compromising the bone's structural integrity.

Method

This study was performed to evaluate the effect of several sterilization methods on the mechanical behavior of human cortical bone graft and histopathology evaluation of tumour bone samples after being processed with 4 different methods of sterilization. Fresh human cortical tumour bone is harvested from the diaphyseal region of the tumour bone were sterilized by autoclave (n =10); boiling (n =10); pasteurization (n =10); and irradiation (n =10). There were also 10 control specimens that did not receive any form of sterilization treatment. The biomechanical test conducted were stress to failure, modulus and strain to failure, which were determined from axial compression testing. Statistical analysis (ANOVA) was performed on these results. Significance level (α) and power (β) were set to 0.05 and 0.90, respectively.

Results

ANOVA analysis of 'failure stress', 'modulus' and 'strain to failure' demonstrated significant differences (p < 0.05) between treated cortical bone and untreated specimens under mechanical loading.

'Stress to failure' was significantly reduced in boiled, autoclaved and irradiated cortical bone samples (p < 0.05). 'Modulus' detected significant differences in the boiled, autoclaved and pasteurization specimens compared to controls (p < 0.05). 'Strain to failure' was reduced by irradiation (p < 0.05) but not by the other three methods of treatments.

Histopathology study revealed no viable tumour cell in any of four types of treatment group compared to the untreated control group.

Conclusions

Sterilization of cortical bone sample by pasteurization and to a lesser extent, irradiation does not significantly alter the mechanical properties when compared with untreated samples. Mechanical properties degrade with the use of high temperature for sterilization (boiling). All methods of sterilization gave rise to 100 percent tumour kill.

Reconstruction of the proximal humerus by combined use of extracorporeally-irradiated osteochondral graft and free vascularized fibula following resection of Ewing sarcoma

Reconstruction of the proximal humerus following limb-saving resection of malignant bone tumor is extremely challenging. We describe here a novel anatomical reconstruction technique in a young patient. A 6-year-old girl with Ewing sarcoma of the proximal humerus was treated by wide excision of the tumor followed by reconstruction with extracorporeally-irradiated osteoarticular autograft combined with an intramedullary inserted free vascularized fibula graft. Proper alignment of the shoulder joint was maintained with no osteoarthritic changes after 16 months. The resulting limb function was satisfactory. This biological reconstruction method was safe and without serious complication. It is indicated for the reconstruction of non-weight-bearing joints and is ideal for the proximal humerus.

Combined use of free vascularised fibula graft and extracorporeally irradiated osteochondral graft for osteosarcoma of the proximal ulna

The elbow is an uncommon site for malignant bone tumors. Surgical options for the reconstruction of the elbow joint are limited and technically challenging. In this study, we describe a patient with osteosarcoma of the proximal ulna treated by wide resection and reconstruction with a combined use of free vascularised fibula graft and extracorporeally irradiated osteochondral graft. Ten years after the surgery, the patient is alive, without disease and is able to play golf with no lateral instability or pain of the elbow joint. A vascularised fibula, combined with extracorporeally irradiated osteochondral graft with ligamentous repair is one of the options for the treatment of malignant bone tumor of the proximal ulna.

Effects of flow shear stress and mass transport on the construction of a large-scale tissue-engineered bone in a perfusion bioreactor

Currently, a tissue-engineered bone is usually constructed using a perfusion bioreactor in vitro. In the perfusion culture, fluid flow can exert shear stress on the cells seeded on scaffold, improving the mass transport of the cells. This experiment studied the effects of flow shear stress and mass transport, respectively, on the construction of a large-scale tissue-engineered bone using the critical-sized beta-tricalcium phosphate scaffold seeded with human bone marrow-derived mesenchymal stem cells (hBMSCs). This was done by changing flow rate and adding dextran into the media, thus changing the media's viscosity. The cells were seeded onto the scaffolds and were cultured in a perfusion bioreactor for up to 28 days with different fluid flow shear stress or different mass transport. When the mass transport was 3 mL/min, the flow shear stress was, respectively, 0.005 Pa (0.004-0.007 Pa), 0.011 Pa (0.009-0.013 Pa), or 0.015 Pa (0.013-0.018 Pa) in different experiment group obtained by simulation and calculation using fluid dynamics. When the flow shear stress was 0.015 Pa (0.013-0.018 Pa), the mass transport was, respectively, 3, 6, or 9 mL/min. After 28 days of culture, the construction of the tissue-engineered bone was assessed by osteogenic differentiation of hBMSCs and histological assay of the constructs. Extracellular matrix (ECM) was distributed throughout the entire scaffold and was mineralized in the perfusion culture after 28 days. Increasing flow shear stress accelerated the osteogenic differentiation of hBMSCs and improved the mineralization of ECM. However, increasing mass transport inhibited the formation of mineralized ECM. So, both flow shear stress and transport affected the construction of the large-scale tissue-engineered bone. Moreover, the large-scale tissue-engineered bone could be better produced in the perfusion bioreactor with 0.015 Pa (0.013-0.018 Pa) of fluid flow shear stress and 3 mL/min of mass transport.

Histological examination of frozen autograft treated by liquid nitrogen removed after implantation

BACKGROUND

Several oncological sterilization methods involving autoclaving, irradiation, or pasteurization have been developed for limb reconstruction of large bone defects following tumor excision. Studies involving histological examinations of these autografts have all found that osteogenesis occurs slowly. We have used frozen autografts treated by liquid nitrogen for limb reconstruction and have achieved excellent results for bone union. To determine if frozen autografts exhibit early bone remodeling, we investigated the repair processes of the frozen bones.

METHODS

We analyzed frozen autografts treated by liquid nitrogen, retrieved at a mean of 19.1 months (2-75 months) after implantation because of complications or local tumor recurrence. The specimens were obtained from six patients with a mean age of 36.2 years (8-68 years). The six grafts comprised three osteoarticular grafts, two intercalary grafts, and one joint graft. We histologically reviewed the autograft-containing sections for tumor cell necrosis, evidence of cortical repair, the cortical junction, and joint cartilage.

RESULTS

Tumor cells were completely eradicated from the frozen bone in all cases. In a specimen retrieved 5 months after implantation, a small area of the bone showed active osteocytes and osteoblasts. In three cases retrieved more than 1 year after implantation, osteocytes and osteoblasts were observed in broad portions of the frozen bones, indicating the onset of osteogenesis in the frozen bone at an early stage. The cortical host-graft junction showed incorporation along with continuity of bone trabeculae. In addition, we were able to fi nd normal chondrocytes on the articular surface.

CONCLUSIONS

The frozen bone specimens in this study thus showed evidence of newly formed bone and earlier osteogenesis than has been previously reported. Our results suggest that frozen autografts may be considered one of the most useful recycled materials for biological reconstruction.

Reconstruction of the proximal humerus with a composite of extracorporeally irradiated bone and endoprosthesis following excision of high grade primary bone sarcomas

INTRODUCTION

Functional reconstruction of the shoulder joint following excision of a malignant proximal humeral tumour is a difficult proposition.

METHOD

Eleven patients with primary osteosarcoma or Ewing's sarcoma underwent reconstruction with a composite of extra-corporeally irradiated autograft with the addition of a long stemmed hemiarthroplasty. At a mean follow-up of 5.8 years two patients had died from disseminated disease and one patient had undergone amputation for local recurrence. The eight patients with a surviving limb were examined clinically and radiographically.

RESULT

The mean Toronto Extremity Salvage Score was 74 and Musculo-Skeletal Tumour Society score 66. Rotation was well preserved but abduction (mean 32 degrees ) and flexion (40 degrees ) were poor. There was a high rate of secondary surgery, with five out of eleven patients requiring re-operation for complications of reconstruction surgery. Radiographic estimate of graft remaining at follow up was 71%. There were no infections, revisions or radiographic failures.

CONCLUSION

Whilst the reconstructions were durable in the medium term, the functional outcome was no better than with other reported reconstructive methods. The composite technique was especially useful in subtotal humeral resections, allowing preservation of the elbow joint even with very distal osteotomy. Bone stock is restored, which may be useful for future revision surgery in this young group of patients.

Extracorporeal irradiation for pelvic reconstruction in Ewing’s sarcoma

We review the treatment of pelvic Ewing’s sarcoma by the implantation of extracorporeally-irradiated (ECI) autografts and compare the outcome with that of other reported methods.

We treated 13 patients with ECI autografts between 1994 and 2004. There were seven males and six females with a median age of 15.7 years (interquartile range (IQR) 12.2 to 21.7). At a median follow-up of five years (IQR 1.8 to 7.4), the disease-free survival was 69% overall, and 75% if one patient with local recurrence after initial treatment elsewhere was excluded. Four patients died from distant metastases at a mean of 17 months (13 to 23). There were three complications which required operative intervention; one was a deep infection which required removal of the graft. The functional results gave a mean Musculoskeletal Tumor Society score of 85% (60% to 97%), a mean Toronto extremity salvage score of 86% (69% to 100%) and a mean Harris hip score of 92 (67 to 100).

We conclude that ECI grafting is a suitable form of treatment for localised and resectable pelvic Ewing’s sarcoma.

Intercalary femoral reconstruction with extracorporeal irradiated autogenous bone graft in limb-salvage surgery

Between 1996 and 2003, 16 patients (nine female, seven male) were treated for a primary bone sarcoma of the femur by wide local excision of the tumour, extracorporeal irradiation and re-implantation. An additional vascularised fibular graft was used in 13 patients (81%). All patients were free from disease when reviewed at a minimum of two years postoperatively (mean 49.7 months (24 to 96). There were no cases of infection. Primary union was achieved after a median of nine months (interquartile range 7 to 11). Five host-donor junctions (16%) united only after a second procedure. Primary union recurred faster at metaphyseal junctions (94% (15) at a median of 7.5 months (interquartile range 4 to 12)) than at diaphyseal junctions (75% (12) at a median of 11.1 months (interquartile range 5 to 18)). Post-operatively, the median Musculoskeletal Tumour Society score was 85% (interquartile range 75 to 96) and the median Toronto Extremity Salvage score 94% (interquartile range 82 to 99). The Mankin score gave a good or excellent result in 14 patients (88%). The range of movement of the knee was significantly worse when the extracorporeally irradiated autografts were fixed by plates rather than by nails (p = 0.035). A total of 16 (62%) of the junctions of the vascularised fibular grafts underwent hypertrophy, indicating union and loading. Extracorporeal irradiation autografting with supplementary vascularised fibular grafting is a promising biological alternative for intercalary reconstruction after wide resection of malignant bone tumours of the femur.

Combined use of free vascularised bone graft and extracorporeally-irradiated autograft for the reconstruction of massive bone defects after resection of malignant tumour

We review eight patients who underwent curative resection for malignant musculoskeletal tumour followed by reconstruction with vascularised bone graft in combination with extracorporeally-irradiated autograft. This method consists of (1) wide en-bloc resection of the tumour; (2) curettage of tumour from the resected bone; (3) extracorporeal irradiation with 60 to 70 Gy as a bolus single dose; (4) vascularised bone grafting from the fibula (six cases) or scapula (two cases); (5) re-implantation of the irradiated bone into the recipient and fixation with plates and screws. Five cases were located in the tibial shaft and one each in the ulnar shaft, distal femur and acetabulum. Radiological and functional outcomes were excellent in four patients who were reconstructed with vascularised fibula and irradiated intercalary tibial bone graft. Two patients with irradiated osteochondral graft showed osteoarthritic change in the long term. No local recurrences arising from the irradiated bones were detected. Combination of a vascularised and an extracorporeally-irradiated bone graft is a useful reconstructive tool for massive bone defects arising from resection of malignant musculoskeletal tumour. This approach has the advantage of combining the biological properties provided by the vascularised bone graft with the mechanical endurance of the irradiated bone autograft. The method is best indicated for intercalary defects of the tibia.

Kinetics of in vivo bone deposition by bone marrow stromal cells within a resorbable porous calcium phosphate scaffold: An X-ray computed microtomography study

Resorbable ceramic scaffolds based on Silicon stabilized tricalcium phosphate (Si-TCP) were seeded with bone marrow stromal cells (BMSC) and ectopically implanted for 2, 4, and 6 months in immunodeficient mice. Qualitative and quantitative evaluation of the scaffold material was performed by X-ray synchrotron radiation computed microtomography (microCT) with a spatial resolution lower than 5 microm. Unique to these experiments was that microCT data were first collected on the scaffolds before implantation and then on the same scaffolds after they were seeded with BMSC, implanted in the mice and rescued after different times. Volume fraction, mean thickness and thickness distribution were evaluated for both new bone and scaffold phases as a function of the implantation time. New bone thickness increased from week 8 to week 16. Data for the implanted scaffolds were compared with those derived from the analysis of the same scaffolds prior to implantation and with data derived from 100% hydroxyapatite (HA) scaffold treated and analyzed in the same way. At variance with findings with the 100% HA scaffolds a significant variation in the density of the different Si-TCP scaffold regions in the pre- and post-implantation samples was observed. In particular a post-implantation decrease in the density of the scaffolds, together with major changes in the scaffold phase composition, was noticeable in areas adjacent to newly formed bone. Histology confirmed a better integration between new bone and scaffold in the Si-TCP composites in comparison to 100% HA composites where new bone and scaffold phases remained well distinct.

Pham Q, Sharma U, Sikavitsas VI, Jansen JA, Mikos AG. In vitro generated extracellular matrix and fluid shear stress synergistically enhance 3D osteoblastic differentiation

This study instituted a unique approach to bone tissue engineering by combining effects of mechanical stimulation in the form of fluid shear stresses and the presence of bone-like extracellular matrix (ECM) on osteodifferentiation. Rat marrow stromal cells (MSCs) harvested from bone marrow were cultured on titanium (Ti) fiber mesh discs for 12 days in a flow perfusion system to generate constructs containing bone-like ECM. To observe osteodifferentiation and bone-like matrix deposition, these decellularized constructs and plain Ti fiber meshes were seeded with MSCs (Ti/ECM and Ti, respectively) and cultured in the presence of fluid shear stresses either with or without the osteogenic culture supplement dexamethasone. The calcium content, alkaline phosphatase activity, and osteopontin secretion were monitored as indicators of MSC differentiation. Ti/ECM constructs demonstrated a 75-fold increase in calcium content compared with their Ti counterparts after 16 days of culture. After 16 days, the presence of dexamethasone enhanced the effects of fluid shear stress and the bone-like ECM by increasing mineralization 50-fold for Ti/ECM constructs; even in the absence of dexamethasone, the Ti/ECM constructs exhibited approximately a 40-fold increase in mineralization compared with their Ti counterparts. Additionally, denatured Ti/ECM* constructs demonstrated a 60-fold decrease in calcium content compared with Ti/ECM constructs after 4 days of culture. These results indicate that the inherent osteoinductive potential of bone-like ECM along with fluid shear stresses synergistically enhance the osteodifferentiation of MSCs with profound implications on bone-tissue-engineering applications.