A Retrospective Analysis of Sacroiliac Joint Pain Interventions: Intraarticular Steroid Injection and Lateral Branch Radiofrequency Neurotomy.

BACKGROUND: Sacroiliac joint (SIJ) pain is a common etiology of chronic lower back pain. Treatment of persistent sacroiliac joint pain may entail intraarticular steroid injections and lateral branch radiofrequency neurotomy. OBJECTIVES: This study evaluates the efficacy of SIJ intervention treatments by comparing intraarticular steroid injections with lateral branch radiofrequency neurotomy. STUDY DESIGN: Retrospective cohort study. SETTING: We reviewed electronic medical records of patients with SIJ pain at Massachusetts General Hospital from 2006  through 2016 and identified 354 patients who received 930 SIJ intraarticular  injections and 19 patients who received 41 SIJ lateral branch radiofrequency neurotomies. METHODS: The Numeric Rating Scale (NRS) score for pain and the Eastern Cooperative Oncology Group (ECOG) Performance Status were measured prior to intervention and on follow-up. A mixed effects model was used to evaluate the duration of treatment effect. RESULTS: Patients who received an SIJ intraarticular steroid injection reported lower pain scores following treatment with a mean (standard deviation) NRS reduction from 6.77 (2.25) to 2.72 (2.81). SIJ lateral branch radiofrequency neurotomy resulted in NRS reduction from 5.96 (2.39) to 3.54 (3.14). A linear mixed model analysis suggests SIJ intraarticular steroid injections provided an estimated mean (CI 95%) of 38 (30-46.3) days of pain relief. Lateral branch radiofrequency neurotomy provided 82 (39.4-124.8) days of pain relief. The mean preprocedure ECOG score was 1.22 for both interventions and trended toward improvement with a post SIJ intraarticular injection score of 1.05 and SIJ lateral branch radiofrequency neurotomy score of 1.03. LIMITATIONS: There was variable follow-up reporting among patients. The small size of the lateral branch radiofrequency cohort limited intergroup comparisons. CONCLUSION: Both SIJ intraarticular steroid injections and SIJ lateral branch radiofrequency neurotomy demonstrated significant pain relief for patients with SIJ pain. SIJ lateral branch radiofrequency neurotomy provided a longer duration of pain relief (82 days) versus SIJ intraarticular steroid injection (38 days).

Ultrasmall Superparamagnetic Iron Oxide Imaging Identifies Tissue and Nerve Inflammation in Pain Conditions.

Objective: Correlation between radiologic structural abnormalities and clinical symptoms in low back pain patients is poor. There is an unmet clinical need to image inflammation in pain conditions to aid diagnosis and guide treatment. Ferumoxytol, an ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle, is clinically used to treat iron deficiency anemia and showed promise in imaging tissue inflammation in human. We explored whether ferumoxytol can be used to identify tissue and nerve inflammation in pain conditions in animals and humans. Methods: Complete Freud's adjuvant (CFA) or saline was injected into mice hind paws to establish an inflammatory pain model. Ferumoxytol (20 mg/kg) was injected intravenously. Magnetic resonance imaging (MRI) was performed prior to injection and 72 hours postinjection. The changes in the transverse relaxation time (T2) before and after ferumoxytol injection were compared between mice that received CFA vs saline injection. In the human study, we administered ferumoxytol (4 mg/kg) to a human subject with clinical symptoms of lumbar radiculopathy and compared the patient with a healthy subject. Results: Mice that received CFA exhibited tissue inflammation and pain behaviors. The changes in T2 before and after ferumoxytol injection were significantly higher in mice that received CFA vs saline (20.8 ± 3.6 vs 2.2 ± 2.5, P = 0.005). In the human study, ferumoxytol-enhanced MRI identified the nerve root corresponding to the patient's symptoms, but the nerve root was not impinged by structural abnormalities, suggesting the potential superiority of this approach over conventional structural imaging techniques. Conclusions: Ferumoxytol-enhanced MRI can identify tissue and nerve inflammation and may provide a promising diagnostic tool in assessing pain conditions in humans.

The natural history of asymptomatic severe carotid artery stenosis.

BACKGROUND: Although level 1 evidence supports carotid endarterectomy (CEA) for stroke prevention in patients with asymptomatic severe carotid artery stenosis (ASCAS; >70%), medical therapy alone has been promulgated by some as equally effective. The goal of this study was to determine the natural history of medically treated patients with ASCAS. METHODS: Patients with ASCAS from 2005 to 2006 were identified in a health network database. Patients were included if the initial therapeutic plan involved medical therapy alone (usually because of comorbidities or patient preference). Study end points included: ipsilateral neurologic symptoms (INS) of transient ischemic attack and/or stroke, death, and INS and/or death. RESULTS: There were 126 carotid arteries identified in 115 patients. Using standard duplex velocity criteria, 88 (70%) had severe (70%-89%) and 38 (30%) had very severe stenoses (VSS; 90%-99%). The average age was 73.5 years, demographic characteristics included: 66% hypertension, 64% coronary artery disease, 30% diabetes, 5% chronic kidney disease (CKD), and 86% were taking a statin drug (28% had a low-density lipoprotein level <100 mg/dL). There were 31 patients (24.6%) who developed INS during a mean follow-up of 27 months; most (23 of 31; 74%) occurred within 12 months of the initial duplex ultrasound examination; 14 (45%) were strokes. The 5-year actuarial freedom from INS was 70.1 ± 5%. Multivariate predictors of INS included: VSS (hazard ratio [HR], 3.23; 95% confidence interval [CI], 1.56-6.76; P = .002), CKD (HR, 6.25; 95% CI, 2.05-19.2; P = .001), and age (HR, 0.94; 95% CI, 0.91-0.98; P = .001). There were 41 patients (33%) who underwent eventual carotid revascularization (32 CEA, nine stent); 23 of 41 (56%) were performed for INS and 18 (44%) for plaque progression. Overall 5-year actuarial survival was 69.8% ± 4.1%. Multivariate predictors of death included: age (HR, 1.06; 95% CI, 1.03-1.1; P = .0001), chronic obstructive pulmonary disease (HR, 1.92; 95% CI, 1.08-3.41; P = .03), and diabetes (HR, 5.08; 95% CI, 2.86-9.01; P < .0001). The 5-year actuarial freedom from INS and/or death was 54 ± 4.4%. Multivariate predictors of INS and/or death were: VSS (HR, 1.98; 95% CI, 1.22-3.23; P = .006), CKD (HR, 5.46; 95% CI, 2.12-14.08; P = .0004), and diabetes (HR, 2.6; 95% CI, 1.59-4.24; P = .0001). Statin use was not protective against INS or death in this cohort. CONCLUSIONS: Medically managed patients with ASCAS develop INS early, especially in patients with VSS. Medical therapy with aspirin and statins failed to control ASCAS, thus validating the role of CEA in these patients as promulgated in multiple current treatment guidelines.