What is the preferred treatment, Evenity (romosozumab) or Forteo (teriparatide), for a patient with osteoporosis needing spinal fusion surgery?

Forteo (Teriparatide) is the Preferred Agent for Osteoporotic Patients Requiring Spinal Fusion

For patients with osteoporosis needing spinal fusion surgery, Forteo (teriparatide) should be the first-line anabolic agent based on Grade B evidence from the Congress of Neurological Surgeons demonstrating superior fusion rates, earlier fusion, and reduced hardware complications compared to bisphosphonates. 1

Evidence Supporting Teriparatide Over Evenity

Direct Guideline Recommendations

The Congress of Neurological Surgeons (2021) provides Grade B recommendation that preoperative teriparatide treatment increases bone mineral density, induces earlier and more robust fusion, and improves select patient outcomes in osteoporotic patients undergoing spinal instrumentation. 1 In contrast, there is no guideline-level evidence supporting Evenity (romosozumab) specifically for the spinal fusion population. 1

Superiority in Fusion Outcomes

Teriparatide achieves 82% fusion rate at 8 months compared to 68% fusion rate at 10 months with bisphosphonates, representing both higher rates and faster time to fusion. 1, 2 This translates to approximately 2-month earlier fusion, which is clinically meaningful for surgical recovery and return to function. 1

Hardware Complication Reduction

Teriparatide demonstrates only 7% incidence of pedicle screw loosening compared to 13% with bisphosphonates and 15% in untreated controls. 1, 2 Meta-analysis data shows teriparatide-treated patients have 2.15-fold higher likelihood of successful fusion compared to non-teriparatide groups. 3

Critical Cardiovascular Safety Concerns with Evenity

Evenity carries a black box warning for increased risk of myocardial infarction, stroke, and cardiovascular death, and is contraindicated in patients who have had MI or stroke within the preceding year. 4 This is particularly relevant in the elderly osteoporotic population undergoing major spine surgery, where cardiovascular risk factors are common. 4

• Evenity should not be initiated in patients with recent cardiovascular events (within 1 year). 4
• If cardiovascular event occurs during Evenity therapy, it must be discontinued immediately. 4
• Teriparatide has no such cardiovascular contraindications in its FDA labeling. 5

Optimal Treatment Protocol for Spinal Fusion

Preoperative Administration Timeline

Administer teriparatide for at least 3 months preoperatively to achieve substantial anabolic effect from the early postoperative stage. 6 Bone histomorphometry data demonstrates:

• Mineralizing surface begins increasing after 1 month of teriparatide. 6
• Significant increases occur after 3 months of administration. 6
• Peak effect occurs at 4 months with 6-fold increase in bone formation parameters. 6
• Patients receiving ≥3 months preoperative teriparatide had superior clinical results in osteoporotic complication rates. 6

Postoperative Continuation

Continue teriparatide for 6-12 months postoperatively to maximize fusion success and minimize hardware complications. 7, 8 Data shows that teriparatide started immediately after surgery significantly reduces screw loosening during the 6-12 month postoperative period (2.3% vs 9.2% with bisphosphonates). 8

Mandatory Sequential Therapy

Immediately transition to antiresorptive therapy (bisphosphonate or denosumab) after completing teriparatide to prevent rapid bone loss. 7 Discontinuing anabolic agents without follow-up antiresorptive results in rapid bone loss and increased fracture risk within 12-18 months. 7

When Evenity Might Be Considered (Rare Scenarios)

Evenity should only be considered if:

• Patient has documented intolerance to teriparatide (severe hypercalcemia, allergic reaction). 4
• Patient has no cardiovascular risk factors whatsoever (extremely rare in elderly osteoporotic population). 4
• Patient has contraindications to teriparatide (prior radiation therapy to skeleton, bone metastases, Paget's disease, open epiphyses). 7, 5

However, even in these scenarios, the lack of spine surgery-specific data for Evenity makes it a less evidence-based choice. 4

Absolute Contraindications to Both Agents

Do not use teriparatide or romosozumab in patients with: 7, 5

• Prior radiation therapy involving the skeleton
• Bone metastases or skeletal malignancies
• Paget's disease of bone
• Open epiphyses (pediatric/young adult patients)

Clinical Outcomes Beyond Fusion

Teriparatide treatment is associated with: 3

• 84% reduction in subsequent vertebral fractures (OR 0.16)
• Significant reduction in sagittal malalignment
• Lower limb pain scores (VAS reduction of 0.36 points)
• Lower spinal pain scores (VAS reduction of 0.24 points)

Common Pitfall to Avoid

Do not use Evenity simply because it is "newer" or marketed as more potent. 4 The spine surgery literature overwhelmingly supports teriparatide with Level II evidence and formal guideline recommendations, while Evenity has no spine surgery-specific validation and carries significant cardiovascular risks. 1, 4