Iatrogenic Cushing syndrome following lumbar medial branch block in a patient with HIV on ritonavir and darunavir

We present a case report of a 62-year old female with HIV and chronic facetogenic back pain who underwent bilateral L3–L4 and L4–L5 medial branch nerve blocks using triamcinolone acetonide 80 mg. 2 weeks later she presented to the emergency department with acute anxiety/depression and was discharged with psychiatric follow-up. 2 weeks after this she presented to the outpatient HIV clinic with persistent uncontrolled depression alongside classic cushingoid features (e.g., buffalo hump, moon facies). She was diagnosed with iatrogenic Cushing syndrome caused by a drug–drug interaction between triamcinolone and ritonavir, a protease inhibitor and a CYP3A4 enzyme inhibitor. While the literature describes the interaction of ritonavir with intra-articular/intranasal/epidural triamcinolone, this is the first documented occurrence following a nerve block procedure. Symptoms resolved within 6 months alongside discontinuation of protease inhibitor therapy.

Predictors of response to medial branch block, radiofrequency ablation or facet joint injections: a retrospective study

Aim: Low back pain is a leading cause of patient disability in the USA. Our goal was to determine association between patient characteristics and their response to lumbar medial branch block, radiofrequency ablation of medial nerves or lumbar facet joint injections. Materials & methods: Medical records for the first 100 patients who underwent lumbar medial branch block, radiofrequency ablation of lumbar medial nerves or lumbar facet joint injections between 1 September 2019 and 31 March 2020 were reviewed and demographic data were recorded. Results: At the 3-month post-procedure visit, positive responders were significantly more likely to be non obese patients (BMI <30) and those with pain <5-years. Conclusion: Obesity and chronicity of pain certainly are found to be predictors of response to the above mentioned procedures.

Predicting Treatment Success with Facet Syndrome: An Algorithm to Predict Lumbar Radiofrequency Ablation Responders in a Military Population

Objective Radiofrequency ablation (RFA) of the medial branch nerve is a commonly performed procedure for patients with facet syndrome. RFA has previously been demonstrated to provide long-term functional improvement in approximately 50% of patients, including those who had significant pain relief after diagnostic medial branch block. We sought to identify factors associated with success of RFA for facet pain. Design Active-duty military patients who underwent lumbar RFA (L3, L4, and L5 levels) over a 3-year period were analyzed. Defense and Veterans Pain Rating Scale (DVPRS) and Oswestry Disability Index (ODI) scores were assessed the day of procedure and at the 2-month and 6-month follow-up. These data were analyzed to identify associations between patient demographics, pain, and functional status and patients’ improvement after RFA, with a primary outcome of ODI improvement and a secondary outcome of pain reduction. Results Higher levels of starting functional impairment (starting ODI scores of 42.9 vs. 37.5; P = 0.0304) were associated with a greater likelihood of improvement in functional status 6 months after RFA, and higher starting pain scores (DVPRS pain scores of 6.1 vs. 5.1; P &lt; 0.0001) were associated with a higher likelihood that pain scores would improve 6 months after RFA. A multivariate logistic regression was then used to develop a scoring system to predict improvement after RFA. The scoring system generated a C-statistic of 0.764, with starting ODI, pain scores, and both gender and smoking history as independent variables. Conclusions This algorithm compares favorably to that of diagnostic medial branch block in terms of prediction accuracy (C-statistic of 0.764 vs. 0.57), suggesting that its use may improve patient selection in patients who undergo RFA for facet syndrome.

Radiofrequency denervation of the lumbar facet joints: guidelines for the RADICAL randomised controlled trial

Background and aim: The RADICAL trial has been funded by the National Institute for Health Research (NIHR) to evaluate the clinical and cost-effectiveness of radiofrequency denervation (RFD) for low back pain. Recommendations have been published which aim to standardise selection of patients and RFD technique. However, it is important to ensure these recommendations are acceptable to clinicians within the context of the trial. The aim of this work was to develop standardised criteria for the trial entry and RFD technique for implementation within the RADICAL trial. Methods: Fourteen pain clinicians completed a survey, which involved reviewing the current recommendations and indicating whether they disagreed with any of the recommendations and if so why. Responses were collated and presented at a half-day workshop with 14 attendees. During the workshop, the National Low Back and Radicular Pain Pathway (NLBRPP) guidelines for patient selection and an article by Eldabe and colleagues presenting recommendations on the RFD technique were reviewed. Attendees discussed whether each component of the recommendations should be mandatory, mandatory with alteration or clarification or optional within the RADICAL trial. Results: Attendees agreed during the workshop that 5 of the 10 criteria for patient selection described in the NLBRPP should be mandatory within the RADICAL trial. Three were agreed as mandatory criteria but required further clarification, one of which involved defining a positive response to a diagnostic medial branch block as ⩾60% pain relief. Two criteria had optional components. After reviewing the recommendations on the RFD technique from Eldabe and colleagues, seven components were agreed as mandatory, three were mandatory with alterations and three were optional. Conclusion: When evaluating complex interventions, such as RFD, it is important to ensure agreement and clarity on the clinical protocol, so that the intervention can be reproduced, if found to be effective.