Surgical Intervention vs. Radiation Therapy: The Shifting Paradigm in Treating Metastatic Spinal Disease

Management of Metastatic Spinal Disease - A Practical Approach

STUDY DESIGN

Narrative review.

OBJECTIVE

This review presents a comprehensive approach to the management of spinal metastases.

METHODS

N/A.

RESULTS

The wide spectrum of clinical presentation in spinal metastases necessitates a personalized approach to treatment planning. This includes a comprehensive diagnostic workup, oncological management, palliation of symptoms, and surgical intervention if appropriate. A systematic and multidisciplinary approach allows optimal shared decision making to reach an evidence-informed and value-congruent treatment plan for the patient. We highlight how advances in stereotactic body radiotherapy (SBRT) and separation surgery may be incorporated into clinical management from a spine surgeon's perspective.

CONCLUSION

This review summarizes the approach and management of spinal metastases, its outcomes and complications.

Comparative study of Lutetium-177 and Phosphorus-32 in radioactive bone cement for the treatment of vertebral body metastasis

BACKGROUND

Vertebroplasty is a minimally invasive outpatient procedure to stabilize compression fractures in the spine. This procedure involves injecting bone cement into the vertebrae that have been cracked or broken, typically due to osteoporosis. The cement hardens inside the bones, providing stability to the fractures and supporting the spine. Additionally, radioactive bone cement and brachytherapy sources have been utilized to suppress tumor growth in the vertebral body.

OBJECTIVE

We present a novel brachytherapy technique for treating vertebral body metastases using a liquid form of radioactive sources, Phosphorus-32 and Lutetium-177, separately mixed with bone cement and injected into vertebral body bone prostheses. We also investigated the dose distribution of the radioactive bone cement by theoretically calculating it using GEANT4 Monte Carlo and measuring it using TLD dosimeters for Phosphorus-32 and Lutetium-177 loaded in vertebral bodies.

MATERIAL AND METHODS

CT-scanned images of each vertebral body (L2 and L3) were imported into GEANT4 for simulation purposes. Two simulations were performed to evaluate the possibility of using PLA prostheses in ex vivo measurements, using bone and PLA material as a bone substitute for brachytherapy of Lutetium-177 and Phosphorus-32. The simulations calculated the dose distribution, dose rates, and deposited dose to the spinal cord and aorta. Next, 3D-printed bone prostheses were drilled and separately filled with bone cement, including PMMA-P32 and PMMA-Lu177, in liquid form using the Vertebroplasty technique. The dose to regions of interest was measured using Thermoluminescence dosimeters.

CONCLUSIONS

When comparing the simulated and measured results of dose rates, it was observed that P32 delivers higher doses to normal organs such as the spinal cord and aorta. At the same time, Lu177 has better sparing in these regions of interest. Therefore, while P32 and Lu177 are suitable for radioactive bone cement treatment, Lu177 delivers relatively lower doses to vital organs such as the spinal cord and aorta. Additionally, Lu177 has characteristics such as a shorter range and lower energies of beta particles in tissue and the presence of gamma rays that make it a better choice for the same treatments. It also provides the possibility of SPECT imaging.

An Overview of Decision Making in the Management of Metastatic Spinal Tumors

INTRODUCTION

Spinal metastases are the most commonly encountered spinal tumors. With increasing life expectancy and better systemic treatment options, the incidence of patients seeking treatment for spinal metastasis is rising. Radical resections and conventional low-dose radiotherapy have given way to modern 'separation' surgeries and stereotactic body radiotherapy which entails lesser morbidity and improved local control. This article provides an overview of the decision making and currently available treatment options for metastatic spinal tumors.

METHODS

A MEDLINE literature search was made for studies in English language reporting on human subjects, describing results of various treatment options that are a part of multidisciplinary management of metastatic spinal tumors. The highest-quality evidence available in the literature was reviewed.

DISCUSSION

Treatment of patients with metastatic spinal tumors is largely palliative, with radiotherapy and selective surgery being the mainstays of management. Multidisciplinary management that incorporates factors like patient performance status, expected survival and systemic burden of disease and employs well-validated decision-making frameworks for guiding treatment holds the key to an effective palliative treatment strategy. Effective pain management, achieving local control, adequate neurological decompression in the setting of epidural cord compression and surgical stabilization for mechanical stabilization are the main goals of treatment.

CONCLUSION

The management of metastatic spinal tumors has been rapidly evolving; currently, limited decompression and stabilization followed by postoperative SBRT for local tumor control are associated with less morbidity and may be referred to as the current standard of care in these patients.