Owning the Bone in Spine Surgery
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.
Guest Post: Own the Bone Improves Osteoporosis Care
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Brett A. Freedman, MD.
In the December 21, 2016 edition of the Journal of Bone & Joint Surgery, Bunta, et al. published an analysis of data from the Own the Bone quality improvement program collected between January 1, 2010 and March 31, 2015. Over this period of time, 125 sites prospectively collected detailed osteoporosis and bone health-related data points on men and women over the age of 50 who presented with a fragility fracture.
The Own the Bone initiative is more than a data registry; it’s a quality improvement program intended to provide a paradigm for increasing the diagnostic and therapeutic recognition (i.e. “response rate”) of the osteoporosis underlying fragility fractures among orthopaedic practices that treat these injuries. With more than 23,000 individual patients enrolled, and almost 10,000 follow-up records, this is the most robust dataset in existence on the topic.
This initiative has more than doubled the response rate among orthopaedic practices treating fragility fractures. The number of institutions implementing Own the Bone grew from 14 sites in 2005-6 to 177 in 2015. According to Bunta et al., 53% of patients enrolled in the Own the Bone quality Improvement program received bone mineral density testing and/or osteoporosis therapy following their fracture.
Own the Bone was a natural progression of rudimentary efforts that came about during the Bone and Joint Decade, and it marks a strategic effort on the part of the American Orthopedic Association to identify and treat the osteoporosis underlying fragility fractures. Multiple studies have demonstrated that only 1 out of every 4 to 5 patients who present with a fragility fracture will receive a clinical diagnosis of osteoporosis and/or active treatment to prevent secondary fractures related to osteoporosis. Ample Level-1 evidence demonstrates that the initiation of first-line agents like bisphosphonates, or second-line agents when indicated, can reduce the chance of a subsequent fragility fracture by at least 50%. We know these medicines work.
We also know that osteoporosis is a progressive phenomenon. Therefore, failing to respond to the osteoporosis underlying fragility fractures means we as a medical system fail to treat the root cause in these patients. The fracture is a symptom of an underlying disease that needs to be addressed or it will continue to produce recurrent fractures and progressive decline in overall health.
The members of the Own the Bone initiative must be commended for their admirable work. We as an orthopedic community need to attempt to incorporate lessons learned through the Own the Bone experience into our practice to ensure that we provide complete care to those with a fragility fracture. The report from Bunta et al. represents a large—but single—step forward on the journey toward universal recognition and treatment of the diminished bone quality underlying fragility fractures. I look forward to additional reports from this group detailing their continued success in raising the bar of understanding and intervention.
Brett A. Freedman, MD is an orthopaedic surgeon specializing in spine trauma and degenerative spinal diseases at the Mayo Clinic in Rochester, MN.
Atypical Femoral Fractures: Predicting Post-surgical Healing Problems
Orthopaedic journals and OrthoBuzz have devoted ample space to the apparent association between long-term bisphosphonate use and atypical femoral fractures. The latest insight into this relationship comes from Lim et al. in the December 7, 2016 edition of The Journal of Bone & Joint Surgery. The authors analyzed factors associated with delayed union or nonunion after surgical treatment of 109 atypical femoral fractures in patients who had an average 7.4-year history of bisphosphonate use.
Here’s what Lim et al. found among the 30% of patients studied who had delayed union or nonunion, relative to the 70% who had successful healing:
- Patient Factors: Patients who had problematic fracture healing had a higher BMI, longer duration of bisphosphonate exposure, and higher rate of prodromal symptoms.
- Radiographic/Fracture Factors: Supra-isthmic/subtrochanteric fracture location, femoral bowing of ≥10° in the coronal plane, and a lateral/medial cortical thickness ratio of ≥1.4 were predictive of problematic healing.
- Operative Factors: Iatrogenic cortical breakage around the fracture site and a ratio of ≥0.2 between the remaining gap and the cortical thickness on the anterior and lateral sides of the fracture site were associated with problematic fracture healing.
In an accompanying commentary on the study, Edward J. Harvey, MD notes that most trauma surgeons use cephalomedullary nails to treat atypical femoral fractures, but that “it is impossible from this manuscript to determine what effect the fixation technique had on the outcomes.” He therefore recommends a larger multicenter study using standardized therapy and bone biopsies to further improve understanding in this area.
BMJ Studies Address Safety of Devices and Alendronate
BMJ recently published two studies of interest to orthopaedists:
- After analyzing data from more than 200 cardiovascular, orthopaedic, and neurologic devices approved in both the US and European Union (EU), Hwang et al. found that those approved in the EU first were nearly three times as likely to trigger a safety alert or experience a recall than those first approved in the US. Finding further that trial results were published for fewer than half of approved devices considered “major innovations,” the authors call for “greater regulatory transparency” so physicians and patients can make better-informed decisions. Interestingly, Figure 2 in this study showed that the FDA approval time for orthopaedic devices was faster than ortho-device approval times in the EU. However, a JBJS study earlier this year found that devices approved via the FDA’s “quick” 510(k) process were 11.5 times more likely to be recalled than those cleared through the longer and more stringent FDA pathway.
- In the second BMJ article, a registry-based case-control study, Abrahamsen et al. found that the long-term use of the bisphosphonate alendronate does not increase the risk for atypical femoral fractures (either subtrochanteric or femoral shaft), while protecting against hip fractures. After applying some sophisticated statistical analyses, the authors estimated that 38 patients with ≥5 years of alendronate adherence would need to be treated for an additional 5 years to prevent one hip fracture, while 1449 similar patients would need to be treated to cause an atypical femoral fracture. Click here for more OrthoBuzz coverage of the relationship between bisphosphonates and atypical femoral fractures.
Recent Comments