This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.
Approximately 20% of patients who undergo spine surgery have osteoporosis, which has a significant impact on spine-surgery complications such as failure of fixation devices and collapse fractures following fusion procedures. In a recent critical analysis review, authors focus on improving outcomes by identifying and optimizing patients with osteoporosis prior to spine surgery. The multidisciplinary team involved in that process should include primary care providers, endocrinologists, physical therapists, and orthopaedic surgeons.
The predominant tool for assessing bone mineral density (BMD) is dual x-ray absorptiometry. The diagnosis is based on a T score, which represents the number of standard deviations between the patient’s BMD and that of a healthy 30-year-old woman. Standard deviations ≤─2.5 define osteoporosis. The Z score is similar to the T score but compares the patient to an age- and sex-matched individual.
A history of low-energy fracture, such as a wrist fracture following a fall from a standing height, is considered a sentinel event for suspicion of fragility fractures. The combination of a fragility fracture and low BMD is considered to be severe osteoporosis. The most common form of osteoporosis is associated with a postmenopausal decrease in mineralization, but there are other causes. These include advanced kidney disease, hypogonadism, Cushing disease, vitamin D deficiency, anorexia and/or bulimia, rheumatoid arthritis, hyperthyroidism, primary hyperparathyroidism, and some medications (e.g., anticonvulsants, corticosteroids, heparin, and proton pump inhibitors).
Forty-seven percent of patients undergoing spine deformity surgery and 64% of cervical spine surgery patients have low vitamin D levels. Postoperative bone health can be enhanced in women ≥51 years old with daily intake of 800 to 1,000 units of vitamin D and 1,200 mg of daily calcium. There is no solid evidence that pre- or postoperative bisphosphonates have a positive impact on bone healing. Conversely, some series have shown that teriparatide, an anabolic parathyroid hormone, may improve time-to-fusion and help reduce screw pull-out after lumbar fusion in postmenopausal women.
Calcitonin has been shown to reduce the incidence of vertebral compression fracture, but there is no concrete evidence that it supports spine-fusion healing. Similarly, there is no strong evidence for the use of estrogen or selective estrogen receptor modulators in this surgical scenario. There is evidence that when the human monoclonal antibody denosumab is combined with teriparatide, spine-fusion healing may be improved relative to the use of teriparatide alone. Finally, the review article identifies screw size, screw position, and other surgical considerations that can improve fixation strength.
Using the “Own the Bone” practices promulgated by the American Orthopaedic Association and the technical considerations described in this review, we should be able to mitigate osteoporosis-related postoperative complications in spine-surgery patients.
OrthoBuzz has published several posts about osteoporosis, fragility fractures, and secondary fracture prevention. In the May 17, 2017 edition of JBJS, Bogoch et al. add to evidence suggesting that a coordinator-based fracture liaison service (FLS) improves engagement with secondary-prevention practices among inpatients and outpatients with a fragility fracture.
The Division of Orthopaedic Surgery at the University of Toronto initiated a coordinator-based FLS in 2002 to educate patients with a fragility fracture and refer them for BMD testing and management, including pharmacotherapy if appropriate. Bogoch et al. analyzed key clinical outcomes from 2002 to 2013 among a cohort of 2,191 patients who were not undergoing pharmacotherapy when they initially presented with a fragility fracture.
- Eighty-four percent of inpatients and 85% of outpatients completed BMD tests as recommended.
- Eighty-five percent of inpatients and 79% of outpatients who were referred to follow-up bone health management were assessed by a specialist or primary care physician.
- Among those who attended the referral appointment, 73% of inpatients and 52% of outpatients received a prescription for anti-osteoporosis medication.
The authors conclude that “a coordinator-based fracture liaison service, with an engaged group of orthopaedic surgeons and consultants…achieved a relatively high rate of patient investigation and pharmacotherapy for patients with a fragility fracture.”