Pre-operative bone quality deficits and risk of complications following spine fusion surgery among postmenopausal women.

Poor bone quality is a risk factor for complications after spinal fusion surgery. This study investigated pre-operative bone quality in postmenopausal women undergoing spine fusion and found that those with small bones, thinner cortices and surgeries involving more vertebral levels were at highest risk for complications. PURPOSE: Spinal fusion is one of the most common surgeries performed worldwide. While skeletal complications are common, underlying skeletal deficits are often missed by pre-operative DXA due to artifact from spinal pathology. This prospective cohort study investigated pre-operative bone quality using high resolution peripheral CT (HRpQCT) and its relation to post-operative outcomes in postmenopausal women, a population that may be at particular risk for skeletal complications. We hypothesized that women with low volumetric BMD (vBMD) and abnormal microarchitecture would have higher rates of post-operative complications. METHODS: Pre-operative imaging included areal BMD (aBMD) by DXA, cortical and trabecular vBMD and microarchitecture of the radius and tibia by high resolution peripheral CT. Intra-operative bone quality was subjectively graded based on resistance to pedicle screw insertion. Post-operative complications were assessed by radiographs and CTs. RESULTS: Among 50 women enrolled (age 65 years), mean spine aBMD was normal and 35% had osteoporosis by DXA at any site. Low aBMD and vBMD were associated with "poor" subjective intra-operative quality. Skeletal complications occurred in 46% over a median follow-up of 15 months. In Cox proportional models, complications were associated with greater number of surgical levels (HR 1.19 95% CI 1.06-1.34), smaller tibia total area (HR 1.67 95% CI1.16-2.44) and lower tibial cortical thickness (HR 1.35 95% CI 1.05-1.75; model p < 0.01). CONCLUSION: Women with smaller bones, thinner cortices and procedures involving a greater number of vertebrae were at highest risk for post-operative complications, providing insights into surgical and skeletal risk factors for complications in this population.

Epidural Steroid Injections Acutely Suppress Bone Formation Markers in Postmenopausal Women.

CONTEXT: Over 9 million epidural steroid injections (ESIs) are performed annually in the United States. Although these injections effectively treat lumbar radicular pain, they may have adverse consequences, including bone loss. OBJECTIVE: To investigate acute changes in bone turnover following ESI. We focused on postmenopausal women, who may be at greatest risk for adverse skeletal consequences due to the combined effects of ESIs with aging and estrogen deficiency. METHODS: Single-center prospective observational study. Postmenopausal women undergoing lumbar ESIs and controls with no steroid exposure were included. Outcomes were serum cortisol, markers of bone formation, osteocalcin, and procollagen type-1 N-terminal propeptide (P1NP), and bone resorption by C-telopeptide (CTX) measured at baseline, 1, 4, 12, 26, and 52 weeks after ESIs. RESULTS: Among ESI-treated women, serum cortisol declined by ~50% 1 week after injection. Bone formation markers significantly decreased 1 week following ESIs: osteocalcin by 21% and P1NP by 22%. Both markers remained suppressed at 4 and 12 weeks, but returned to baseline levels by 26 weeks. There was no significant change in bone resorption measured by CTX. Among controls, there were no significant changes in cortisol or bone turnover markers. CONCLUSION: These results provide evidence of an early and substantial reduction in bone formation markers following ESIs. This effect persisted for over 12 weeks, suggesting that ESIs may have lasting skeletal consequences. Given the large population of older adults who receive ESIs, further investigation into the long-term skeletal sequelae of these injections is warranted.

Dopamine agonist withdrawal syndrome (DAWS) in a tertiary Parkinson disease treatment center.

INTRODUCTION: Dopamine agonists are a mainstay of treatment for patients with Parkinson disease (PD). However, side effects limit their use, often necessitating dose change. Upon withdrawal, patients may experience dopamine agonist withdrawal syndrome (DAWS). To date, there is no established protocol for the prevention or treatment of DAWS. METHODS: We performed a retrospective chart review of PD patients who were taking a dopamine agonist. RESULTS: In our large cohort of 313 PD patients who were on a dopamine agonist, we found that 39.5% (n=124) had a change in their dose of medication for various reasons, including 102 patients who experienced a side effect on a dopamine agonist. Twenty out of 102 patients (19.6%) developed symptoms consistent with DAWS, whereas 1 out of 22 patients (4.5%) who had medication dose changed due to any other reason (e.g. dyskinesias, DBS surgery, decreased by another provider, etc.) developed symptoms consistent with DAWS. Our DAWS population had a shorter duration of PD, less exposure to a dopamine agonist, and was on a lower dose compared to those patients who did not develop DAWS. Agitation was the most common DAWS symptom reported in our cohort. Interestingly, in terms of developing DAWS, the prevalence of DAWS (19.0% vs 16.5%; p=0.76) between partial versus total discontinuation was not significantly different whether the dopamine agonist dose was decreased (21 patients) or completely stopped (103 patients). CONCLUSION: Contrary to previous reports, we have found that other side effects besides impulse control behavioral disorders also increase risk for developing DAWS. Furthermore, the prevalence of DAWS did not differ between partial versus total discontinuation of the dopamine agonist.