Local adjuvants in surgical management of bone metastases

Micro-CT, Mechanical, and Histological Examination of the Effect of Local Adjuvants on Porcine Cortical Bone Following Intralesional Curettage of Bone Tumors

BACKGROUND AND OBJECTIVES

Curettage is the removal of a tumor from the bone while preserving the surrounding healthy cortical bone, and is associated with higher rates of local recurrence. To lower these rates, curettage should be combined with local adjuvants, although their use is associated with damage to nearby healthy bone.

OBJECTIVE

The purpose of this analysis is to determine the effect of local adjuvants on cortical porcine bone by using micro-computed tomography (micro-CT) along with histological and mechanical examination.

METHODS

Local adjuvants were applied to porcine specimens under defined conditions. To assess changes in bone mineral density (BMD), a micro-CT scan was used. The pixel gray values of the volume of interest (VOI) were evaluated per specimen and converted to BMD values. The Vickers hardness test was employed to assess bone hardness (HV). The depth of necrosis was measured histologically using hematoxylin and eosin-stained tissue sections.

RESULTS

A noticeable change in BMD was observed on the argon beam coagulation (ABC) sample. Comparable hardness values were measured on samples following electrocautery and ABC, and lowering of bone hardness was obtained in the case of liquid nitrogen. Extensive induced depth of necrosis was registered in the specimen treated with liquid nitrogen.

CONCLUSION

This study determined the effect of local adjuvants on cortical bone by using micro-CT along with histological and mechanical examination. Phenolization and liquid nitrogen application caused a decrease in bone hardness. The bone density was affected in the range of single-digit percentage values. Liquid nitrogen induced extensive depth of necrosis with a wide variance of values.

The role of surgery in the treatment of metastatic bone tumor

Surgery for bone metastasis has two primary goals-palliative care to relieve pain, instability and paralysis, and tumor resection for curing the disease. Oncologically en bloc resection, followed by a reconstruction of the bone defect is the treatment of choice in single bone metastasis from renal cell carcinoma or thyroid cancer. Bone metastases may occur in the extremities, pelvis, or spine, and different resection and reconstruction methods depend on the regional anatomy. For instance, multiple options are available for reconstruction of the pelvis, especially for the acetabulum, including anatomical reconstruction using custom-made implants or recycled autologous bone grafting when a long-term prognosis is expected. Recently, for the spine, total en bloc spondylectomy is extensively performed despite the initial limitations of surgical invasiveness, such as blood loss. Principally, palliative surgery aims to maintain lasting bony stability with minimal surgical invasiveness. Intramedullary nails and plate fixation are frequently used in the extremities but the postoperative failure rate is relatively high. Therefore, surgeons should consider the use of long intramedullary nails and long-type stems for endoprosthesis reconstruction along with cement fixation to reduce the failure rate. Although short-term complications, such as dislocation, have been observed with endoprosthesis reconstruction, it is stable in the long-term follow-up. Percutaneous bone cement injection into the spine and pelvis is also effective and less invasive.

Recent Advances in the Treatment of Bone Metastases and Primary Bone Tumors: An Up-to-Date Review

In the last decades, the treatment of primary and secondary bone tumors has faced a slow-down in its development, being mainly based on chemotherapy, radiotherapy, and surgical interventions. However, these conventional therapeutic strategies present a series of disadvantages (e.g., multidrug resistance, tumor recurrence, severe side effects, formation of large bone defects), which limit their application and efficacy. In recent years, these procedures were combined with several adjuvant therapies, with different degrees of success. To overcome the drawbacks of current therapies and improve treatment outcomes, other strategies started being investigated, like carrier-mediated drug delivery, bone substitutes for repairing bone defects, and multifunctional scaffolds with bone tissue regeneration and antitumor properties. Thus, this paper aims to present the types of bone tumors and their current treatment approaches, further focusing on the recent advances in new therapeutic alternatives.

A comparison of depth of necrosis among adjuvant therapies used for the treatment of benign bone tumors

BACKGROUND AND OBJECTIVES

Benign bone tumors are often treated with extended curettage utilizing an adjuvant therapy to eliminate any remaining tumor cells. The purpose of this study was to explore and compare the histologic depth of necrosis created by various adjuvant therapies used in the treatment of benign bone tumors.

METHODS

A high-speed burr was utilized to create cortical defects within porcine humeri and femora. Phenol, polymethyl methacrylate (PMMA), argon beam coagulation (ABC), liquid nitrogen, and the Bipolar Hemostatic Sealer (BHS) were each applied to five defects, with an additional five defects left untreated as a control. The maximal depth of necrosis was determined under microscopic examination.

RESULTS

The phenol, PMMA, ABC, liquid nitrogen, and BHS demonstrated an average histologic depth of necrosis of 0.30, 0.78, 2.54, 2.54, and 0.92 mm, respectively, each of which was significantly increased compared to the control group (p = .001, .003, .003, .01, and  <.001). Their respective variances, a measure of reproducibility, were 0.01, 0.09, 0.96, 1.93, and 0.03 mm² .

CONCLUSION

This study confirms, through histologic analysis, adjuvant therapies create a rim of cellular necrosis beyond that of burring during extended curettage, supporting their use in the treatment of benign bone tumors. Furthermore, it provides a head-to-head comparison.

Which one of the benign tumors and tumor-like lesions located in long bones needs prophylactic fixation during surgery?

Objectives

This study aims to define the simultaneous prophylactic fixation indications of benign tumors and tumor-like lesions located in long bones that were treated by curettage and grafting/cementing.

Patients and methods

Fifty-six patients (33 males, 23 females; mean age 30.9±15.9; range, 15 to 65 years) who were treated by curettage and grafting or cementation for their benign tumors or tumor-like lesions in long bones between January 2013 and June 2016 were retrospectively analyzed. Age, sex, anamnesis and physical examination findings, histopathologic diagnosis, lesion localization, pre- and postoperative imaging results and follow-up data were all analyzed. The patients were divided into two groups as those with and without postoperative fracture.

Results

The most common localization was femur (38%). The mean tumor diameter was 6.8±2.2 (range, 2.6 to 12.6) cm and volume was 58.3±45.0 (range, 6 to 177) cm³. Postoperative fracture occurred in 14 patients. The lesion diameter and volume of the patients in postoperative fracture group were significantly higher compared to group without postoperative fracture (p=0.034 and p=0.004, respectively). A volume value greater than 67 cm³ and ages over 35 years were found to be associated with a higher rate of fracture for all lesions.

Conclusion

In the postoperative period, patients with benign tumors or tumor-like lesions of long bones had a higher fracture risk if the volume value was greater than 67 cm³ and the age was over 35 years. Prophylactic fixation may be suggested for these patients.

Total en bloc spondylectomy combined with the satellite rod technique for spinal tumors

Background

Instrumentation failure (IF) is a common complication after total en bloc spondylectomy (TES) in spinal tumors. This study aims to evaluate the clinical outcomes of TES combined with the satellite rod technique for the treatment of primary and metastatic spinal tumors.

Methods

The clinical data of 15 consecutively treated patients with spinal tumors who underwent TES combined with the satellite rod technique by a single posterior approach from June 2015 to September 2018 were analyzed retrospectively. Radiographic parameters including the local kyphotic angle (LKA), anterior vertebral height (AVH), posterior vertebral height (PVH), and intervertebral titanium mesh cage height (ITMCH) were assessed preoperatively, postoperatively, and at the final follow-up. The visual analog scale (VAS), Oswestry Disability Index (ODI), and American Spinal Injury Association (ASIA) scale were used to assess quality of life and neurological function. The operative duration, volume of blood loss, and complications were also recorded.

Results

The mean operation time and volume of blood loss were 361.7 min and 2816.7 mL, respectively. During an average follow-up of 31.1 months, 2 patients died of tumor recurrence and multiple organ metastases, while recurrence was not found in any other patients. Solid fusion was achieved in all but one patient, and no implant-related complications occurred during the follow-up. The VAS, ODI, and ASIA scores significantly improved from before to after surgery (P < 0.05). The LKA, AVH, and PVH significantly improved from before to immediately after surgery and to the final follow-up (P < 0.05), and the postoperative and final follow-up values did not significantly differ (P > 0.05).

Conclusions

TES combined with the satellite rod technique can yield strong three-dimensional fixation and reduce the occurrence of rod breakage, thereby improving the long-term quality of life of patients with spinal tumors.

Early postoperative compilations of bone filling in curettage defects

Background

Curettage is widely used in orthopedic oncology; the defect created frequently requires filling for mechanical and functional stability for the bones and adjacent joint. Allograft, bone graft substitute, and polymethyl methacrylate (PMMA) are the most common substances used each with their benefits and drawbacks. The aim of the study is to show that good functional result can be achieved with curettage and bone filler, regardless of type.

Methods

A series of 267 cases were reviewed between 1994 and 2015 who received curettage treatment and placement of a bone filler. Endpoints included fracture, infection, cellulitis, pulmonary embolism, and paresthesia. Complication rates at our single institution were compared against literature values for three study cohorts: allograft, bone graft substitute, and PMMA bone fillers. Friedman test, Wilcoxon test, and Z-score for two populations were used to compare our subset against literature values and between different bone filling types.

Results

Our cases included 18 autografts, 74 allografts, 121 bone graft substitute, and 54 PMMA of which the bulk of complications occurred. Our overall complication rate was 3.37%. Allograft has a complication rate of 1.35%, bone graft substitute of 4.13%, and PMMA of 5.56%. Other techniques did not yield any complications. Combination filling techniques PMMA + allograft and PMMA + bone graft substitute had sample sizes too small for statistical comparison. Statistical comparison yielded no significant difference between complications in any of the filling groups (P = 0.411).

Conclusions

Some has even argued that bone defects following curettage do not require bone filling for good outcome. However, many structural or biologic benefits that aid in earlier return to functionality can be conferred by filling large bone defects. There was no significant difference in postoperative complication rates between allograft, bone graft substitute, and PMMA when compared at our institution and with literature values. Nevertheless, one complication with a large defect filled with allograft, requiring a subsequent reconstruction using vascularized fibular graft. Taking everything into account, we see bone graft substitute as a suitable alternative to other bone filling modalities.

Surgical therapy of benign and low-grade malignant intramedullary chondroid lesions of the distal femur: intralesional resection and bone cement filling with or without osteosynthesis

Surgical treatment of benign and low-grade malignant intramedullary chondroid lesions at the distal femur is not well analyzed compared to higher-grade chondrosarcomas. Localization at the distal femur offers high biomechanical risks requiring sophisticated treatment strategy, but scientific guidelines are missing. We therefore wanted to analyze a series of equally treated patients with intralesional resection and bone cement filling with and without additional osteosynthesis. Twenty-two consecutive patients could be included with intralesional excision and filling with polymethylmethacrylate bone cement alone (n = 10) or with compound bone cement osteosynthesis using a locking compression plate (n = 12). Clinical and radiological outcome was retrospectively evaluated including tumor recurrences, complications, satisfaction, pain, and function. Mean follow-up was 55 months (range 7–159 months). Complication rate was generally high with lesion-associated fractures both in the osteosynthesis group (n = 2) and in the non-osteosynthesis group (n = 2). All fractures occurred in lesions that reached the diaphysis. No fractures were found in meta-epiphyseal lesions. No tumor recurrence was found until final follow-up. Clinical outcome was good to excellent for both groups, but patients with additional osteosynthesis had significantly longer surgery time, more blood loss, longer postoperative stay in the hospital, more complications, more pain, less satisfaction, and worse functional outcome. Intralesional resection strategy was oncologically safe without local recurrences but revealed high risk of biomechanical complications if the lesion reached the diaphysis with an equal fracture rate no matter whether osteosynthesis was used or not. Additional osteosynthesis significantly worsened final clinical outcome and had more overall complications. This study may help guide surgeons to avoid overtreatment with additional osteosynthesis after curettage and bone cement filling of intramedullary lesions of the distal femur. Meta-epiphyseal lesions will need additional osteosynthesis rarely, contrary to diaphyseal lesions with considerable cortical thinning.

Drug-eluting implants for the suppression of metastatic bone disease: current insights

INTRODUCTION

The fixation of impending or pathologic fractures is challenging and their successful management can have a favourable impact on the quality of life of the patient. The progression of the metastatic bone disease can cause significant pain and disability but also could result in the loosening and subsequent failure of the implants. To prevent the additional local growth, postoperative radiotherapy is often recommended, and many patients receive endocrine or chemotherapy.

AREAS COVERED

Several reports support the antineoplastic drugs to bone cement as an adjuvant to improve implant stability as well as to prevent local cancer progression and failure of reconstructive devices used to treat patients with pathologic fractures. The aim of the present review is to present our current understanding on the effect of local delivery of antineoplastic drugs at the bone site.

EXPERT COMMENTARY

Encouraging evidence support the application of bone cement loaded with antineoplastic drugs to fill defects and strengthen the fixation of orthopaedic implants. This is an inexpensive and safe method that can improve implant stability, prevent local cancer progression and failure of reconstructive devices. To fully evaluate its clinical effectiveness randomized clinical studies are needed.

Reducing kyphotic deformity by posterior vertebral column resection with 360° osteosynthesis in metastatic epidural spinal cord compression (MESCC)

PURPOSE

Metastatic epidural spinal cord compression (MESCC) often requires anterior-posterior decompression and stabilization. To reduce approach-related complications, single-stage posterolateral vertebrectomy and 360° fusion is often performed. However, a sufficient reduction of kyphotic deformity through this approach has not been reported. The purpose of this study is to investigate the efficacy of kyphotic deformity reduction by this approach in MESCC.

METHODS

A retrospective analysis and chart review was performed for 14 consecutive patients who underwent a vertebrectomy and decompression from a posterolateral approach. Anterior mesh stabilization of the ventral column is used as hypomochlion for the posterior compression manoeuvre, which leads to reduction of the kyphotic deformity.

RESULTS

Pre-operative back pain was 7.2 on a visual analogue scale. Back pain was reduced to 4.4 at discharge and 2.0 at the latest follow-up with a mean follow-up of 12 months (p < 0.001). The Frankel score remains constant or improved from D to E. Radiological segmental kyphosis was corrected from a mean of 16° to 4° (p < 0.001) post-operatively with a loss of 3° at the final follow-up, but still with significant corrections compared with the pre-operative measurements (p < 0.003).

CONCLUSION

Single-stage posterolateral vertebrectomy and reconstruction is a safe and less invasive approach that allows a sufficient reduction of hyperkyphosis and preservation of neurological function in patients with MESCC. This approach is an efficient alternative to anterior-posterior fusion with good pain reduction and improved sagittal profile.

Indications for prophylactic osteosynthesis associated with curettage in benign and low-grade malignant primitive bone tumors of the distal femur in adult patients: a case series

BACKGROUND

The aim of the study was to evaluate whether the use of preventive osteosynthesis after curettage in benign and primitive low-grade malignant bone tumor localized in the distal femur in adult patients provides sufficient mechanical stability to the system as to allow weight-bearing and reduce the risk of postoperative fracture. Additionally, lower limb function after curettage and preventive osteosynthesis was evaluated.

MATERIALS AND METHODS

We analyzed twelve cases of benign and low-grade malignant bone lesions of the distal femur in adult patients treated in our orthopedic department between 2008 and 2011 with curettage, bone filling and preventive osteosynthesis. All patients were treated with curettage with the use of high-speed cutters, plus liquid nitrogen as local adjuvant in low-grade malignant lesions, and filling of the lesion with bone graft or allograft or acrylic cement, followed by osteosynthesis.

RESULTS

No fractures or major complications were observed; good function of the knee was observed.

CONCLUSION

We recommend preventive osteosynthesis after curettage in patients with very large lesions (>5 cm, >60 cm³) or high functional requirements, in obese patients, and when local adjuvants are used.

LEVEL OF EVIDENCE

Level IV retrospective case-series study.