What are the anabolic agents for a patient prior to spinal surgery?

Anabolic Agents for Patients Prior to Spinal Surgery

Teriparatide is the recommended anabolic agent for patients with osteoporosis undergoing spinal instrumentation, as it reduces postoperative complications including screw loosening and improves fusion rates. 1

Primary Recommendation: Teriparatide

Clinicians should consider preoperative teriparatide in osteoporotic patients undergoing spinal instrumentation to decrease the risk of postoperative adverse events, including screw loosening and delayed or lower rates of fusion (Grade B recommendation). 1

Evidence Supporting Teriparatide

The Congress of Neurological Surgeons (2021) provides the strongest guideline evidence for anabolic therapy in the perioperative spine surgery setting:

• Teriparatide demonstrates superior outcomes compared to bisphosphonates in patients undergoing spinal fusion, with screw loosening rates of only 7% versus 13% with bisphosphonates 1, 2

• Fusion rates are significantly higher with teriparatide (82% at 8 months) compared to bisphosphonates (68% at 10 months), and fusion occurs approximately 2 months earlier 1, 2

• Bone mineral density recovery is faster with teriparatide, and it increases BMD, induces earlier and more robust fusion, and may improve select patient outcomes 1

Patient Selection Criteria

Teriparatide should be considered for patients who meet the following criteria:

• Confirmed osteoporosis (DEXA T-score < -2.5, CT Hounsfield units < 97.9, or vitamin D3 < 20 ng/mL) 1

• Undergoing spinal instrumentation where screw fixation and fusion are critical to surgical success 1

• Very high fracture risk, particularly those with multiple prior fractures, severe osteoporosis, or those who have failed bisphosphonate therapy 2, 3

Treatment Protocol

• Dosing: 20 mcg subcutaneously once daily into the thigh or abdominal region 4

• Duration: Maximum 2 years during a patient's lifetime, though treatment beyond 2 years may be considered if the patient remains at very high fracture risk 4

• Required supplementation: Calcium 1,000-1,200 mg daily and vitamin D 600-800 IU daily (targeting serum 25(OH)D ≥ 20 ng/mL) 2, 3, 4

• Timing: Ideally initiated preoperatively to optimize bone quality before surgery 1

Critical Contraindications

Absolute contraindications that must be verified before prescribing:

• Bone metastases or history of skeletal malignancies 2, 4
• Prior external beam or implant radiation therapy involving the skeleton 2, 4
• Paget's disease of bone 2, 4
• Open epiphyses 2

Use with extreme caution or avoid in patients with:

• Active malignancy prone to metastasize to bone 2, 4
• Pre-existing cardiac arrhythmias 4

Bisphosphonates: Insufficient Evidence

There is insufficient evidence to support the use of bisphosphonates alone in patients with osteoporosis undergoing spinal instrumentation to decrease postoperative adverse events (Grade Insufficient). 1

While bisphosphonates remain first-line therapy for most osteoporosis patients in general medical practice, the evidence specifically for perioperative spine surgery does not support their use as the primary bone-protective agent when instrumentation is planned 1. Some studies suggest bisphosphonates may even delay fusion in the short term (first 6 months), though overall fusion rates exceed 80% by 2 years 1.

Alternative Anabolic Agent: Romosozumab

While not specifically studied in the spine surgery population, romosozumab represents a promising anabolic agent for patients at very high fracture risk 3, 5. However, given the lack of spine surgery-specific data and the robust evidence for teriparatide, it should not be considered first-line for this indication 5.

Sequential Therapy Considerations

Following completion of anabolic therapy, patients must transition to antiresorptive therapy (bisphosphonate or denosumab) to preserve bone mass gains and prevent rebound fractures 2, 3, 4. This is particularly critical in the spine surgery population where loss of fixation can be catastrophic 1.

Common Pitfalls to Avoid

• Do not use teriparatide as first-line therapy in non-surgical osteoporosis patients, as generic bisphosphonates should be prescribed first due to significantly lower cost 4

• Do not combine teriparatide with bisphosphonates, as teriparatide is best given as monotherapy 4

• Do not forget to screen for osteoporosis preoperatively in elderly patients undergoing spine surgery, as undiagnosed osteoporosis contributes to pseudarthrosis, instrumentation failure, and proximal junctional failure 1

• Do not neglect vitamin D optimization, as vitamin D3 levels < 20 ng/mL predict increased risk of postoperative adverse events 1

Clinical Algorithm for Perioperative Spine Surgery

1. Screen all elderly patients planned for spinal instrumentation with DEXA scan, CT (Hounsfield units), or serum vitamin D3 level 1

2. If osteoporosis confirmed (T-score < -2.5, HU < 97.9, or vitamin D3 < 20 ng/mL), counsel patient regarding increased risk of postoperative complications 1

3. Initiate teriparatide preoperatively at 20 mcg subcutaneously daily, along with calcium and vitamin D supplementation 1, 4

4. Continue teriparatide postoperatively for up to 2 years to optimize fusion and reduce instrumentation complications 1, 2, 4

5. Transition to antiresorptive therapy (bisphosphonate or denosumab) after completing teriparatide to maintain bone gains 2, 3, 4