What is the recommended treatment approach for surgical fixation in spinal metastasis?

Surgical Fixation in Spinal Metastasis: Treatment Approach

Immediate surgical intervention is indicated for spinal metastases causing compression of the spinal cord and/or nerve roots with neurological deficits or uncontrollable pain, with the specific approach determined by the Spinal Instability Neoplastic Score (SINS) and patient prognosis. 1

Assessment and Decision-Making Framework

1. Initial Evaluation

• Use the Spinal Instability Neoplastic Score (SINS) to assess stability:
  • SINS 0-6: Stable lesion
  • SINS 7-12: Potentially unstable - surgical consultation recommended
  • SINS 13-18: Unstable - requires surgical intervention 1

2. Surgical Decision Algorithm

Indications for Surgical Fixation:

• Neurological deficits due to spinal cord/nerve root compression
• Intractable pain unresponsive to conservative management
• Spinal instability (SINS score ≥7)
• Vertebral body fractures causing progressive deformity
• Risk of imminent neurological compromise 1

Factors Influencing Surgical Approach:

• Patient's overall prognosis and life expectancy
• Performance status
• Biology of primary tumor
• Extent of metastatic disease
• Location and size of spinal metastases 1

Surgical Techniques Based on Prognosis

Short-Term Survival (<6 months):

• Palliative decompression via posterior approach
• Spinal instrumentation to restore stability
• Consider minimally invasive techniques (percutaneous fixation)
• Adjuvant radiation therapy 1, 2

Medium-Term Survival (6-12 months):

• More extensive decompression
• Cement vertebral body replacement
• Two-level stabilization
• Consider minimally invasive approaches when feasible 2

Long-Term Survival (>12 months):

• Consider aggressive intervention including total en bloc spondylectomy for solitary lesions
• 360° decompression
• Vertebral body reconstruction
• Multilevel stabilization 1, 2

Specific Surgical Approaches

Anterior Approach:

• Indicated for anterior column involvement
• Allows direct decompression of ventral tumor mass
• Requires vertebral body reconstruction with cement or prosthesis
• Often combined with posterior stabilization 3, 4

Posterior Approach:

• More common for palliative decompression
• Allows for multilevel stabilization
• Less morbidity than combined approaches
• May be insufficient for ventral tumor masses 1

Minimally Invasive Options:

• Percutaneous vertebral augmentation (vertebroplasty/kyphoplasty) for painful vertebral body fractures without significant cord compression
• Endoscopic approaches for selected cases
• Stereotactic radiosurgery as adjunct or alternative in radiation-sensitive tumors 1, 2

Adjunctive Treatments

Radiation Therapy:

• Essential adjunct to surgery in most cases
• SBRT shows superior pain relief compared to conventional EBRT
• Consider timing - typically administered post-operatively 1

Percutaneous Interventions:

• Radiofrequency ablation, cryoablation can be combined with vertebroplasty/kyphoplasty
• Particularly useful for radiation-resistant tumors 1

Post-Surgical Management

• Early mobilization and rehabilitation to improve functional outcomes 5
• Pain management with multimodal approach including opioids and neuropathic pain medications 5
• Antiresorptive therapy (denosumab or bisphosphonates) for prevention of skeletal-related events 1

Complications to Monitor

• Risk of vertebral compression fracture after SBRT (11-39%)
• Hardware failure
• Wound complications
• Adjacent level fractures
• Cement leakage with vertebroplasty/kyphoplasty 1

The surgical management of spinal metastases has evolved significantly, with a focus on circumferential decompression and immediate stabilization. A multidisciplinary approach involving spine surgeons, radiation oncologists, and medical oncologists is essential to optimize outcomes and improve quality of life in these patients.