Effect of methotrexate on distraction osteogenesis

Reconstruction of intercalary bone defect after resection of malignant bone tumor

Due to accurate preoperative imaging techniques, early diagnosis and effective chemotherapy, many tumors arising in the metaphyseo-diaphyseal regions of long bones can be segmentally resected with joint preservation. The intercalary resection of malignant bone tumor results in a bone defect which can represent a challenging reconstructive problem. The most commonly used surgical reconstructive options for these defects include biologic reconstructions such as allografts, vascularized fibular grafts, autogenous extracorporeally devitalized tumor bearing bone graft, combination of allografts or devitalized autografts with vascularized fibular grafts, segmental bone transport, or induced membrane technique. Nonbiologic reconstructions, on the other hand, use intercalary endoprostheses. Every patient should be carefully evaluated and the reconstructive option should be individually selected. The aim of this article is to discuss the surgical options of reconstruction of bone defects after intercalary resection of malignant bone tumors with reviewing of their indications, advantages, disadvantages and complications.

Progress in biological reconstruction and enhanced bone revitalization for bone defects

Bone defect reconstruction with artificial materials may produce good functional recovery in the short term. Over time, the durability of artificial materials becomes an issue, and therefore, artificial materials cannot be considered a permanent solution to reconstruction. For long-term outcomes, the goal is to regain function, permanence, and form that are as close to normal as possible. Thus, physiological materials are desirable for use in reconstruction. Biological reconstruction involves the use of materials that are modified in vivo following reconstruction of bone defects. The goal is to achieve bone union, bone revival and remodeling, with biointegration of soft tissue and bone. Allograft use has been the mainstay of bone defect reconstruction in most parts of the world, although in some countries like Japan, allogeneic bone is difficult to obtain due to socio-religious concerns. Therefore, we developed new biological reconstruction techniques to overcome this problem. Bone derived from distraction osteogenesis is autologous bone, which must be an ideal reconstruction material for its biological affinity, strength, resilience, and immunity to infection. When applying this method to patients with malignant disease however, it is important to preserve as much of the local soft tissue as possible, and the clinician must be especially careful of infection and callus formation. Liquid nitrogen treatment of tumor-bearing bone produces equal, if not better, bone revitalization compared to other forms of treatment to date. Reconstruction with liquid nitrogen-treated bone involves resecting the diseased bone and returning it to the body following liquid nitrogen treatment (free-freezing method). Another method involves dislocating the joint proximal to the tumor, or cutting the bone while the distal side remains attached to the body and the limb inverted and treated with liquid nitrogen (pedicle freezing method). When both methods are possible, the pedicle freezing method is preferable since it is performed with minimal osteotomy. Our recent research has looked into the possible role of adipose-derived stem cells in promoting bone fusion and revitalization. This method has produced promising results for the future of biological reconstruction.

Intercalary reconstructions after bone tumor resections: a review of treatments

An intercalary reconstruction is defined as replacement of the diaphyseal portion of a long bone after segmental skeletal resection (diaphysectomy). Intercalary reconstructions typically result in superior function compared to other limb-sparing procedures as the patient's native joints above and below the reconstruction are left undisturbed. The most popular reconstructive options after segmental resection of a bone sarcoma include allografts, vascularized fibula graft, combined allograft and vascularized fibula, segmental endoprostheses, extracorporeal devitalized autograft, and segmental transport using the principles of distraction osteogenesis. This article aims to review the indications, techniques, limitations, pros and cons, and complications of the aforementioned methods of intercalary bone tumor resections and reconstructions in the context of the ever-growing, brave new field of limb-salvage surgery.

Effect of methotrexate on bone and wound healing

INTRODUCTION

Methotrexate (MTX) is one of the most commonly used disease modifying drugs administered for wide spectrum of conditions. Through the expansion of the indications of MTX use, an increasing number of patients nowadays attend orthopaedic departments receiving this pharmacological agent. The aim of this manuscript is to present our current understanding on the effect of MTX on bone and wound healing. Areas covered: The authors offer a comprehensive review of the existing literature on the experimental and clinical studies analysing the effect of MTX on bone and wound healing. The authors also analyse the available literature and describe the incidence of complications after elective orthopaedic surgery in patients receiving MTX. Expert opinion: The available experimental data and clinical evidence are rather inadequate to allow any safe scientific conclusions on the effect of MTX on bone healing. Regarding wound healing, in vitro and experimental animal studies suggest that MTX can adversely affect wound healing, whilst the clinical studies show that lose-dose MTX is safe and does not affect the incidence of postoperative wound complications.

Nutlin-3 treatment spares cisplatin-induced inhibition of bone healing while maintaining osteosarcoma toxicity

The majority of Osteosarcoma (OS) patients are treated with a combination of chemotherapy, resection, and limb salvage protocols. These protocols include distraction osteogenesis (DO), which is characterized by direct new bone formation. Cisplatin (CDP) is extensively used for OS chemotherapy and recent studies, using a mouse DO model, have demonstrated that CDP has profound negative effects on bone repair. Recent oncological therapeutic strategies are based on the use of standard cytotoxic drugs plus an assortment of biologic agents. Here we demonstrate that the previously reported CDP-associated inhibition of bone repair can be modulated by the administration of a small molecule p53 inducer (nutlin-3). The effects of nutlin-3 on CDP osteotoxicity were studied using both pre- and post-operative treatment models. In both cases the addition of nutlin-3, bracketing CDP exposure, demonstrated robust and significant bone sparing activity (p < 0.01-0.001). In addition the combination of nutlin-3 and CDP induced equivalent OS tumor killing in a xenograft model. Collectively, these results demonstrate that the induction of p53 peri-operatively protects bone healing from the toxic effects of CDP, while maintaining OS toxicity. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1716-1724, 2016.

Cisplatin inhibits bone healing during distraction osteogenesis

Osteosarcoma (OS) is the most common malignant bone tumor affecting children and adolescents. Many patients are treated with a combination of chemotherapy, resection, and limb salvage protocols. Surgical reconstructions after tumor resection include structural allografts, non-cemented endoprostheses, and distraction osteogenesis (DO), which require direct bone formation. Although cisplatin (CDP) is extensively used for OS chemotherapy, the effects on bone regeneration are not well studied. The effects of CDP on direct bone formation in DO were compared using two dosing regimens and both C57BL/6 (B6) and tumor necrosis factor receptor 1 knockout (TNFR1KO) mice, as CDP toxicity is associated with elevated TNF levels. Detailed evaluation of the five-dose CDP regimen (2 mg/kg/day), demonstrated significant decreases in new bone formation in the DO gaps of CDP treated versus vehicle treated mice (p < 0.001). Further, no significant inhibitory effects from the five-dose CDP regimen were observed in TNFR1KO mice. The two-dose regimen significantly inhibited new bone formation in B6 mice. These results demonstrate that CDP has profound short term negative effects on the process of bone repair in DO. These data provide the mechanistic basis for modeling peri-operative chemotherapy doses and schedules and may provide new opportunities to identify molecules that spare normal cells from the inhibitory effects of CDP.

Methods of biological reconstruction for bone sarcoma: indications and limits

Therapy of bone sarcoma has dramatically changed over the past few decades. Several successful interdisciplinary treatment strategies have led to an increase of the survival rates from 20% to 60%-80%. Consequently new demands on the operative treatment of bone and soft tissue sarcoma have arisen. Nowadays limb salvage can be achieved in 80%-90% using tumour megaprostheses or biological reconstruction procedures. In this article we outline the indications and limitations of biological reconstruction procedures after bone tumour resection. We therefore introduce the different biological approaches such as free autologous bone grafting, reimplantation of extracorporeal devitalized autografts or distraction osteogenesis and summarize the currently available data on the individual procedures. Our analyses demonstrate a wide applicability of biological procedures in tumour situations. Although accompanied by considerable complications in the early postoperative phase, biological reconstructions clearly demonstrate the potential of having excellent long-term durability and functionality.

Safety of external fixation during postoperative chemotherapy

We studied the safety of external fixation during post-operative chemotherapy in 28 patients who had undergone distraction osteogenesis (17, group A) or vascularised fibular grafting (11, group B) after resection of a tumour. Four cycles of multi-agent post-operative chemotherapy were administered over a mean period of 14 weeks (6 to 27). The mean duration of external fixation for all patients was 350 days (91 to 828). In total 204 wires and 240 half pins were used.

During the period of post-operative chemotherapy, 14 patients (11 in group A, 3 in group B) developed wire- and pin-track infection. A total of ten wires (4.9%) and 11 half pins (4.6%) became infected. Seven of the ten infected wires were in periarticular locations.

External fixation during post-operative chemotherapy was used safely and successfully for fixation of a vascularised fibular graft and distraction osteogenesis in 27 of 28 patients. Post-operative chemotherapy for malignant bone tumours did not adversely affect the ability to achieve union or cause hypertrophy of the vascularised fibular graft and had a minimal effect on distraction osteogenesis. Only one patient developed osteomyelitis which required further surgery.

Effects of diclofenac and tenoxicam on distraction osteogenesis

INTRODUCTION

In the management of bone defects, pseudoarthrosis, deformities, chronic osteomyelitis and in extremity lengthening procedures, the technique of distraction osteogenesis (DO) has been frequently used. In this experimental animal study, the effects of two non-steroidal anti-inflammatory drugs, i.e., diclofenac and tenoxicam, on the outcomes of distraction osteogenesis are investigated.

MATERIALS AND METHODS

In this study, 30 mature New Zealand-type male rabbits (2.5-4.5 kg) were used. The rabbits were randomized into three groups, each consisting of ten animals. Under optimal operating conditions, a pre-reconstructed circular external fixator was applied on the right tibias of rabbits, and osteotomy was performed with a Gigli saw just below the tibial tuberosity. After seven postoperative days, distraction was initiated at a rhythm of 2 x 0.5 mm/day. During the 10 days of distraction, adjunctive therapy was not instituted for group I (control group). For 10 days, group II received i.m. diclofenac sodium (0.5 mg/kg per day) and group III was treated with tenoxicam (8 mg/kg per day i.m.). At the end of 3 weeks postoperatively, five rabbits from each group were killed for histologic examinations. The remaining rabbits were killed at the end of eight postoperative weeks for biomechanical and histological analysis. Besides, radiological examinations were performed at the end of 3, 6 and 8 weeks postoperatively for the radiologic evaluation of calluses. For statistical evaluations between groups, Kruskal-Wallis variance analysis, and for intergroup assessments, Mann-Whitney test were performed.

RESULTS

For radiological evaluations, the scoring system developed by Lane and Sandhu, and for histopathological assessments, the grading system of Huddlestone et al. were used. Biomechanical tests were realized using torsional loading. During the first 3 weeks, the groups did not differ much in the radiological parameters. However, in the diclofenac group and in especially the tenoxicam group, the histological scores were lower than in the control group. Radiological images obtained at the end of 6 weeks demonstrated inadequate consolidation in the diclofenac and tenoxicam groups when compared with the control group. At the end of 8 weeks postoperatively, in consideration of biomechanical, radiological and histological tests, significantly worse regenerates were obtained in the diclofenac and tenoxicam groups.

CONCLUSIONS

During the distraction osteogenesis period, diclofenac and tenoxicam affected the quality of regenerate unfavorably. This effect is sustained during all periods of bone healing. However, this finding should be supported by experimental and human studies.

Technique and complications of callus distraction in the treatment of bone tumors

INTRODUCTION

This study investigated the effects of chemotherapy, defect length, and patient age on the outcome and complications of callus distraction as a limb salvage technique in 17 patients.

MATERIALS AND METHODS

The mean patient age was 18.4 years (range 7-47). Of 17 patients, 8 received chemotherapy and the remaining 9 patients did not. The mean defect length after excision of the lesion was 13 cm (range 8-20). The mean follow-up period for the patients whose treatments were completed was 55 months (range 20-90), the mean distraction index was 12.55 days/cm (range 11-15.7), and the mean external fixation index was 34.73 days/cm (range 30-41).

RESULTS

In two patients, local recurrence occurred before distraction was completed. Two patients died, and one of them was a patient in whom local recurrence had occurred. Complications included non-union in one patient, osteomyelitis in one patient, and premature callus, osseous bridge, and varus of the femur in one patient. The extremity functional score was 80% (range 26-100). Chemotherapy and defect length had no significant effect on the distraction or external fixation indices. In contrast, the increase in the external fixation index in those over 20 years old was significant (P=0.043).

CONCLUSION

We found that chemotherapy and defect length have no significant effect on the outcome and complications with this technique, which was more successful in patients younger than 20 years.

Case report: Reconstruction of an intercalary defect with bone transport after resection of Ewing's sarcoma

We report a 13-year-old girl with Ewing's sarcoma of the tibia who was treated with multiagent chemotherapy, followed by local control tumor surgery consisting of wide resection of the tumor and bone transport with distraction osteogenesis for reconstruction. The bone defect created by resection was 13 cm long and was replaced by bone transport using a monolateral external fixator. Evaluation of the resected specimen revealed wide tumor-free margins with 100% chemonecrosis. A planned Harmon-type autogenous bone grafting between the middle and proximal segments of the tibia (docking site) was done primarily after docking occurred, and a solid union was obtained by 23 months after resection. The bone healing index (treatment index) was 54 days/1 cm distraction, which is indicative of slow healing. Clinical evaluation of the affected extremity using the Musculoskeletal Tumor Society rating system revealed 80% normal functional capability. Indications for bone transport in reconstruction of bone defects created by wide resection of bone sarcomas are discussed. In retrospect, we have concerns regarding the suitability of this technique in the setting of diaphyseal sarcoma reconstruction in patients with Ewing's sarcoma who require aggressive and intense multiagent chemotherapy.

Effect of neoadjuvant chemotherapy on distraction osteogenesis in the goat model

Neoadjuvant chemotherapy potentially can have an adverse effect on bone healing in distraction osteogenesis whether given before or concomitant with distraction osteogenesis. It was the purpose of the current study to determine if administration of chemotherapy before distraction adversely affects bone generation in distraction osteogenesis. Twenty-four adult dairy goats were divided randomly into two groups: a control group having distraction osteogenesis only and a chemotherapy group, receiving one course of Adriamycin before distraction osteogenesis. The animals were sacrificed at 6 weeks, 12 weeks, or 24 weeks and the lengthened tibias were evaluated by radiologic studies, biomechanical testing, and histologic analysis. All goats receiving chemotherapy showed systemic adverse effects. In a multifactorial analysis of the lengthened bones, there was no statistically significant difference between the control goats versus goats that received chemotherapy; indicating that there was no sustained inhibitory effect on bone formation by the chemotherapy. These findings suggest that a prior course of chemotherapy with Adriamycin may not be a contraindication to limb lengthening for limb salvage after resection of an osteosarcoma.

Distraction osteogenesis enhanced by osteoblastlike cells and collagen gel

Femoral distraction was done in rats to determine whether the injection of osteoblastlike cells with collagen gel into the distracted callus was useful for new bone formation. The cells were obtained from the femoral marrow of Sprague-Dawley rats and cultured for approximately 3 weeks. These rats were divided into four groups. The rats in Group A received injections of physiologic saline, those in Group B received injections of collagen gel, those in Group C received injections of cells, and those in Group D received injections containing a mixture of cells and collagen gel. The distracted areas were harvested and evaluated by histologic analysis, radiography, three-point bending testing, and the weight of femoral ash. Histologic evaluation did not show an immunoreaction between the donor and recipient. Radiographs showed that Group D had the most callus, and the fracture strength in this group as determined by the three-point bending test was higher than in Group A at 2, 4, and 6 weeks after elongation was completed. Group D showed a significant difference in the ash weight of the distracted femurs at 2 weeks. The current study showed that osteoblastlike cells with collagen gel promoted new bone formation in the distracted gap, and shortened the consolidation period.

Effect of cisplatin on bone transport osteogenesis in dogs

OBJECTIVE

To document effects of cisplatin on regenerate bone formation during the distraction and consolidation phases of bone transport osteogenesis.

ANIMALS

10 skeletally mature hounds.

PROCEDURES

Bone transport osteogenesis was performed to reconstruct a 3-cm defect in the radius of each dog. Five dogs were randomly selected to receive cisplatin (70 mg/m2, IV, q 21 d for 4 cycles), and 5 were administered saline (0.9% NaCl) solution. Bone mineral density was measured by use of dual-energy x-ray absorptiometry (DEXA) on days 24, 55, and 90 after surgery. Dogs were euthanatized 90 days after surgery. Histomorphometry was performed on nondecalcified sections of regenerate bone. Bone mineral density and histomorphometric indices of newly formed bone were compared between groups.

RESULTS

Densitometric differences in regenerate bone mineral density were not detected between groups at any time period. Cisplatin-treated dogs had decreased mineralized bone volume, decreased percentage of woven bone volume, decreased percentage of osteoblast-covered bone, increased porosity, and increased percentage of osteoblast-covered surfaces, compared with values for control dogs. Lamellar bone volume and osteoid volume did not differ significantly between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Regenerate bone will form and remodel during administration of cisplatin. Results of histomorphometric analysis suggest that bone formation and resorption may be uncoupled in cisplatin-treated regenerate bone as a result of increased osteoclast activity or delayed secondary bone formation during remodeling. These histomorphometric differences were modest in magnitude and did not result in clinically observable complications or decreased bone mineral density as measured by use of DEXA.