Preoperative Spine Evaluation and Assessment

3. Preoperative Osteoporosis Assessment

Recommendations

Question 1:

What preoperative diagnostic studies predict the risk of osteoporosis-related adverse events after spine surgery?

Recommendation:

Preoperative testing with a DEXA scan T score <−2.5, a CT scan (Hounsfield Unit <97.9), or serum vitamin D3 level <20 ng/mL is associated with poor bone mineral density and predicts an increased risk of a postoperative adverse event in individuals undergoing spinal instrumentation. Preoperative assessment with one of these tests (DEXA scan, CT, or serum vitamin D3 level) should be performed in patients with suspected osteoporosis. Patients with confirmed osteoporosis should be counseled regarding the potential increased risk of postoperative adverse events. Strength of Recommendation: Grade B

Question 2:

Does preoperative treatment of low bone mineral density decrease risk of postoperative adverse event after spine surgery?

Recommendations:

Clinicians should consider preoperative teriparatide in patients with osteoporosis undergoing spinal instrumentation to decrease risk of postoperative adverse events, including screw loosening and a delayed or lower rate of fusion. Strength of Recommendation: Grade B

There is insufficient evidence to support the use of bisphosphonates alone in patients with osteoporosis undergoing spinal instrumentation to decrease postoperative adverse events after spinal instrumentation. Strength of Recommendation: Grade Insufficient

Overview

Osteoporotic fragility fractures have become a major health care epidemic with the aging population, occurring in 2.1 million patients yearly. The spine is affected in 245,000 patients annually, and mortality after a vertebral fracture is 22.4%, 32.7%, and 49.4% at 1, 2, and 4 years, respectively Suboptimal diagnosis and management of bone health before spine surgery can contribute to increased osteoporosis-related postoperative adverse events and unsatisfactory surgical outcomes in the elderly. These include pseudarthrosis, instrumentation complications (particularly loss of fixation at the screw–bone interface), and proximal junctional failure (PJF), with potentially catastrophic spinal fracture with or without neurologic injury. The cause of these postoperative complications may be multifactorial; however, poor bone density is often a major contributor that is potentially modifiable with appropriate preoperative diagnosis and management.

Osteoporosis can result from aging, genetic and environmental factors, certain comorbidities, and abnormal homeostasis of calcium and vitamin D metabolism. Despite the relative prevalence of osteoporosis and vitamin D3 deficiency and various available diagnostic and treatment modalities, there is a lack of consensus regarding the management of osteoporosis before spine surgery. This deficiency may be related to poor understanding by many spine surgeons of bone physiology, limited cost-effective interventions, and the reluctance of spine surgeons to be the primary provider of treatment or to consult an endocrinologist.

This evidence-based clinical guideline provides a recommendation that patients with suspected osteoporosis undergo preoperative assessment and be appropriately counseled about the risk of postoperative adverse events if osteoporosis is confirmed. In addition, preoperative optimization of BMD with select treatments improves certain patient outcomes.  There is insufficient evidence regarding preoperative treatment with bisphosphonates alone and postoperative outcome.

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