How should multiple spinal compression fractures be managed in a patient with multiple myeloma?

Management of Multiple Spinal Compression Fractures in Multiple Myeloma

Balloon kyphoplasty is the treatment of choice for painful vertebral compression fractures in multiple myeloma, providing pain relief in approximately 80% of patients and superior restoration of vertebral height compared to vertebroplasty or conservative management. 1

Immediate Assessment and Risk Stratification

Evaluate for Spinal Cord Compression

• Emergency surgical decompression is indicated for spinal cord compression with bone fragments within the spinal canal 1
• Assess for motor weakness, sensory changes, and bowel/bladder dysfunction requiring urgent intervention 2
• MRI is the most sensitive imaging modality (82-100% sensitivity) for detecting cord compression and bone marrow involvement 3

Assess Spinal Stability

• Use the Spinal Instability Neoplastic Score (SINS) to identify unstable fractures requiring surgical consultation 4
• Approximately 20% of vertebral compression fractures in newly diagnosed myeloma patients are classified as unstable 4
• Surgery is indicated for unstable spinal fractures to prevent neurological deterioration and restore axial skeleton integrity 1, 5

Primary Treatment Algorithm

For Painful Stable Compression Fractures

Balloon kyphoplasty should be performed preferentially over vertebroplasty because it:

• Provides equivalent long-term pain control 6
• Achieves superior restoration of vertebral body height 6
• Results in greater correction of kyphotic deformity 6
• Has lower rates of cement leakage (grade 1A evidence) 1
• Should be performed early (<6-8 weeks from fracture) for superior functional outcomes 6

For Unstable Fractures or Neurological Compromise

• Surgical fixation with instrumentation is required for unstable spinal fractures 1, 5
• Anterior laminectomy when vertebral instability or bone particles compress the spinal cord 5
• Surgery provides rapid decompression and stabilization with 88-96% of patients achieving pain relief and ability to walk at 3 months 7

For Intractable Pain Without Instability

• Radiotherapy at 3000 cGy in 10-15 fractions is effective for extremely painful lytic lesions 1
• Note: radiotherapy may delay systemic anti-myeloma therapies with radiosensitizing drugs (anthracyclines, proteasome inhibitors) 1

Concurrent Systemic Management

Bone-Modifying Agents (Mandatory)

All patients with symptomatic multiple myeloma should receive bisphosphonates or denosumab regardless of documented bone disease (category 1 recommendation) 1

• Zoledronic acid 4 mg IV monthly is preferred for patients with adequate renal function (CrCl >60 mL/min) 1, 8
• Pamidronate is an alternative bisphosphonate option 1, 8
• Denosumab is preferred for patients with renal impairment (CrCl <30 mL/min) 1

Critical renal dosing adjustments:

• CrCl 30-60 mL/min: reduce zoledronic acid dose with no change to infusion time 1
• CrCl 30-60 mL/min: pamidronate via 4-hour infusion 1
• CrCl <30 mL/min: avoid pamidronate and zoledronic acid; use denosumab instead 1

Duration of therapy:

• Continue bone-modifying agents for up to 2 years 1
• Beyond 2 years, continuation depends on clinical judgment 1
• Dosing frequency (monthly vs every 3 months) should be individualized after initial 2 years 1

Mandatory Supportive Care

• Calcium and vitamin D3 supplementation for all patients on bisphosphonates (grade 1A) 1
• Monitor vitamin D levels at least annually 1
• Baseline dental examination before initiating bone-modifying agents 1
• Monitor renal function (CrCl, electrolytes, urinary albumin) before each infusion 1

Pharmacological Pain Management

Acute Pain

• Subcutaneous opioids (oxycodone or morphine) for rapid symptom relief 8
• All patients on opioids must receive laxatives to prevent constipation 8

Chronic Pain

• Gabapentin or pregabalin (calcium channel blockers) 8
• Duloxetine or amitriptyline (serotonin-norepinephrine reuptake inhibitors) 8
• Lidocaine or oxcarbazepine (sodium channel blockers) 8

Critical Pitfalls to Avoid

Osteonecrosis of the Jaw (ONJ)

• Perform thorough dental examination and resolve all major dental problems before starting bisphosphonates (grade 2C) 1
• Long-term zoledronic acid has 3.7% ONJ rate vs 0.5% with clodronate 1
• If ONJ develops, discontinue bisphosphonates; may resume after healing at physician's discretion 1

Renal Toxicity

• Discontinue bisphosphonates if renal function deteriorates until CrCl returns to within 10% of baseline 1
• Denosumab has lower renal toxicity but higher hypocalcemia risk than zoledronic acid 1
• Monitor calcium levels closely, especially in dialysis patients 1

Delayed Intervention

• Early balloon kyphoplasty (<6-8 weeks) provides superior functional outcomes compared to delayed intervention 6
• Spinal cord compression requires emergency management to prevent permanent neurological deficits 5, 2
• 47% of newly diagnosed myeloma patients present with vertebral compression fractures, with 20% classified as unstable 4

Imaging Limitations

• Plain radiographs miss early lesions and require 30-50% bone density loss for visualization 3
• MRI is mandatory for accurate assessment of bone marrow involvement and soft tissue extension 3, 9
• CT provides better characterization of cortical integrity and lesion size 3

Integration with Anti-Myeloma Therapy

• Resume systemic anti-myeloma therapy as soon as wound healing permits after surgery 5
• Effective novel anti-myeloma regimens have reduced the need for surgery over the past decade 1
• Bisphosphonates should be continued post-operatively to reduce bone resorption 5
• Coordinate timing of radiotherapy to avoid delays in radiosensitizing systemic therapies 1, 5