Randomized prospective trial of cooled versus traditional radiofrequency ablation of the medial branch nerves for the treatment of lumbar facet joint pain.

BACKGROUND AND OBJECTIVES: No previous study has assessed the outcomes of cooled radiofrequency ablation (C-RFA) of the medial branch nerves (MBN) for the treatment of lumbar facet joint pain nor compared its effectiveness with traditional RFA (T-RFA). This study evaluated 6-month outcomes for pain, function, psychometrics, and medication usage in patients who underwent MBN C-RFA versus T-RFA for lumbar Z-joint pain. METHODS: In this blinded, prospective trial, patients with positive diagnostic MBN blocks (>75% relief) were randomized to MBN C-RFA or T-RFA. The primary outcome was the proportion of 'responders' (≥50% Numeric Rating Scale (NRS) reduction) at 6 months. Secondary outcomes included NRS, Oswestry Disability Index (ODI), and Patient Global Impression of Change. RESULTS: Forty-three participants were randomized to MBN C-RFA (n=21) or T-RFA (n=22). There were no significant differences in demographic variables (p>0.05). A ≥50% NRS reduction was observed in 52% (95% CI 31% to 74%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.75). A ≥15-point or ≥30% reduction in ODI score was observed in 62% (95% CI 38% to 82%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.21). CONCLUSIONS: When using a single diagnostic block paradigm with a threshold of >75% pain reduction, both treatment with both C-RFA and T-RFA resulted in a success rate of approximately 50% when defined by both improvement in pain and physical function at 6-month follow-up. While the success rate was higher in the C-RFA group, this difference was not statistically significant. TRIAL REGISTRATION NUMBER: NCT02478437.

Patients with a history of hypersensitivity reaction to iodinated contrast medium and given iodinated contrast during an interventional pain procedure.

In patients with a history of a hypersensitivity reaction to iodinated contrast medium, iodinated contrast medium is avoided, antihistamine and steroid premedication are given, or a gadolinium-based contrast agent is employed. Six patients with a history of a hypersensitivity reaction to iodinated contrast medium and who were not premedicated had an unintentional injection of iodinated contrast. None of the patients developed a moderate or severe reaction. All patients had gadopentetate dimeglumine in one of their injections; three had repeated injections of the gadopentetate. The lack of a significant reaction may be due to any or all of the following: questionable history of iodinated contrast reaction, low dose of iodinated contrast given, concomitant injection of (epidural) steroid, and slower absorption from epidural compared with intravenous injection. While it is reassuring to know that there is a low possibility of a moderate to severe reaction in these patients, every effort should be made to avoid this scenario, appropriate drugs and resuscitation equipment should be immediately available, and the patients should be observed adequately and followed for the possibility of late reactions. Recent publications have called for caution in the use of gadolinium-based contrast agents.

A Prospective Randomized Trial of Prognostic Genicular Nerve Blocks to Determine the Predictive Value for the Outcome of Cooled Radiofrequency Ablation for Chronic Knee Pain Due to Osteoarthritis.

Background and Objectives: Genicular nerve radiofrequency ablation is an effective treatment for patients with chronic pain due to knee osteoarthritis; however, little is known about factors that predict procedure success. The current study evaluated the utility of genicular nerve blocks to predict the outcome of genicular nerve cooled radiofrequency ablation (cRFA) in patients with osteoarthritis. Methods: This randomized comparative trial included patients with chronic knee pain due to osteoarthritis. Participants were randomized to receive a genicular nerve block or no block prior to cRFA. Patients receiving a prognostic block that demonstrated ≥50% pain relief for six hours received cRFA. The primary outcome was the proportion of participants with ≥50% reduction in knee pain at six months. Results: Twenty-nine participants (36 knees) had cRFA following a prognostic block, and 25 patients (35 knees) had cRFA without a block. Seventeen participants (58.6%) in the prognostic block group and 16 (64.0%) in the no block group had ≥50% pain relief at six months (P = 0.34). A 15-point decrease in the Western Ontario and McMaster Universities Osteoarthritis Index at six months was present in 17 of 29 (55.2%) in the prognostic block group and 15 of 25 (60%) in the no block group (P = 0.36). Conclusions: This study demonstrated clinically meaningful improvements in pain and physical function up to six months following cRFA. A prognostic genicular nerve block using a local anesthetic volume of 1 mL at each injection site and a threshold of ≥ 50% pain relief for subsequent cRFA eligibility did not improve the rate of treatment success.

Interventional Approaches to Low Back Pain.

Chronic low back pain (LBP) places a tremendous economic burden on society due to both direct and indirect costs. Health care costs for adults with chronic LBP have steadily increased over the past 20 years, coinciding with a large increase in the utilization of spinal injections, surgical interventions, opioid medications, and physical therapy. The treatment of LBP is best approached by a multimodal and even multidisciplinary approach with a combination of physical rehabilitation, pharmacologic management, psychological intervention, spinal injections, and surgical intervention with a goal of improving the functional status of the patient. In this review, we discuss the interventional management of LBP secondary to herniated nucleus pulposus, spinal stenosis, facet mediated pain, sacroiliitis, and discogenic pain.

Diskitis, Osteomyelitis, Spinal Epidural Abscess, Meningitis, and Endocarditis Following Sacroiliac Joint Injection for the Treatment of Low-Back Pain in a Patient on Therapy for Hepatitis C Virus.

OBJECTIVE: Sacroiliac joint injections are frequently performed procedures in the management of acute and chronic low-back pain, including patients with various immunocompromised states. Infectious complications following these procedures along with other spinal injections are rarely reported, but the true incidence is unknown. The purpose of this report is to highlight the devastating neurologic sequela that can occur, and to discuss potential future management strategies. CASE REPORT: We present a patient who developed diskitis, osteomyelitis, spinal epidural abscess, meningitis, and endocarditis from Staphylococcus aureus, all of which developed shortly after a sacroiliac joint injection. The patient was on treatment for hepatitis C virus, and the resulting immunocompromised state likely contributed to the outcome. CONCLUSIONS: Immunocompromised patients should be identified prior to treatment, and the small possibility of devastating complications should be thoughtfully weighed against the potential benefit of the procedure. Conservative management should be maximized initially, and if a procedure is done, strict asepsis must be maintained. Prophylaxis for S. aureus should be considered for immunocompromised patients undergoing interventional spine procedures.

Cooled Radiofrequency Ablation of the Genicular Nerves for Chronic Pain due to Knee Osteoarthritis: Six-Month Outcomes.

OBJECTIVE: Determine outcomes of cooled radiofrequency ablation (C-RFA) of the genicular nerves for treatment of chronic knee pain due to osteoarthritis (OA). DESIGN: Cross-sectional survey. SETTING: Academic pain medicine center. SUBJECTS: Consecutive patients with knee OA and 50% or greater pain relief following genicular nerve blocks who underwent genicular nerve C-RFA. METHODS: Survey administration six or more months after C-RFA. Pain numeric rating scale (NRS), Medication Quantification Scale III (MQSIII), Patient Global Impression of Change (PGIC), and total knee arthroplasty (TKA) data were collected. Logistic regression was used to identify factors that predicted treatment success. RESULTS: Thirty-three patients (52 discrete knees) met inclusion criteria. Thirty-five percent (95% confidence interval [CI] = 22-48) of procedures resulted in the combined outcome of 50% or greater reduction in NRS score, reduction of 3.4 or more points in MQSIII score, and PGIC score consistent with "very much improved/improved." Nineteen percent (95% CI = 10-33) of procedures resulted in complete pain relief. Greater duration of pain and greater than 80% pain relief from diagnostic blocks were identified as predictors of treatment success. The accuracy of the model was 0.88 (95% CI = 0.78-0.97, P < 0.001). CONCLUSIONS: Genicular C-RFA demonstrated a success rate of 35% based on a robust combination of outcome measures, and 19% of procedures resulted in complete relief of pain at a minimum of six months of follow-up. Report of 80% or greater relief from diagnostic blocks and duration of pain of less than five years are associated with high accuracy in predicting treatment success. Further prospective study is needed to optimize the patient selection protocol and success rate of this procedure.

Does Cervical Interlaminar Epidural Steroid Injection with Low-Dose Lidocaine Cause Objective Upper Extremity Weakness? A Preliminary Study.

OBJECTIVE: Low-dose local anesthetic is often used in cervical interlaminar epidural steroid injections (CIESI), yet its effect on upper extremity strength has not been studied. The presence of consequent weakness has potential implications for postprocedure safety. This study aimed to determine whether low-dose lidocaine in a C7-T1 CIESI causes objective weakness. DESIGN: Prospective case series. SETTING: Academic pain center. SUBJECTS: Adults, cervical radicular pain. METHODS: Participants underwent CIESI with 1 mL of 1% lidocaine (3 mL total injectate). Elbow flexion (EF), wrist extension (WE), elbow extension (EE), and handgrip strength were measured by dynamometry at baseline, 15 minutes, and 30 minutes postinjection. Changes in strength from baseline and the proportion of participants with a minimum perceptible change in EF, WE, EE, and handgrip strength (≥20%) and 95% confidence intervals (CIs) were calculated. RESULTS: Twenty-seven participants were included. At 15 and 30 minutes postinjection, there was no within-participant difference in EF, WE, EE, and handgrip strength from baseline overall. Nonetheless, five (19%, 95% CI = 4-33) of the participants demonstrated a 20% or greater strength decrease in at least one myotomal distribution. A 20% or greater decrease in strength was present in left EF 4% (95% CI = 0-11%), right EF 7% (95% CI = 0-17%), left WE 4% (95% CI = 0-11%), and right WE 7% (95% CI = 0-17%). CONCLUSIONS: The present data suggest that CIESI with an injectate volume of 3 mL that includes 1 mL of 1% lidocaine may result in objective upper extremity weakness that is above the minimum threshold of perception in a subset of patients.

A Prospective Randomized Comparative Trial of Targeted Steroid Injection Via Epidural Catheter Versus Standard C7-T1 Interlaminar Approach for the Treatment of Unilateral Cervical Radicular Pain.

BACKGROUND AND OBJECTIVES: No study has compared cervical interlaminar epidural steroid injection (CIESI) with epidural catheter advancement to the side and level of pathology versus standard C7-T1 CIESI. This study investigated whether cervical radicular pain is more effectively treated by CIESI with a targeted epidural catheter versus a standard C7-T1 approach. METHODS: Prospective, randomized, single-blinded trial. PRIMARY OUTCOME: Numerical Rating Scale (NRS) pain at 1 month. SECONDARY OUTCOMES: Oswestry Neck Disability Index (ONDI), Pain Disability Index (PDI), McGill Pain Questionnaire (MPQ), Patient Global Impression of Change (PGIC), daily morphine equivalents (DME), and Medication Quantification Scale (MQS) III scores. RESULTS: Seventy-six participants with a median age of 48 years (IQR, 40-56 years), 59% female, with C4 (n = 2), C5 (n = 27), or C6 (n = 47) radicular pain were enrolled. At 1 month in the catheter and no catheter groups, respectively: 26 (72%, 95% confidence interval [CI], 57%-87%) and 23 (60%; 95% CI, 45%-75%) participants reported 50% or greater NRS reduction; 24 (67%; 95% CI, 52%-84%) and 23 (58%; 95% CI, 42%-73%) participants reported 30% or greater ONDI reduction. There were no group differences in median NRS, ONDI, PDI, MPQ, PGIC, DME, or MQSIII scores (P > 0.05). Intergroup differences were not observed at any follow-up interval. CONCLUSIONS: This trial showed no significant difference in clinical outcomes with CIESI using a targeted epidural catheter compared to a standard C7-T1 approach for the treatment of unilateral cervical radicular pain at the C5 or C6 level. Both techniques were associated with clinically meaningful improvement across outcome domains of pain, function, disability, and medication use. These effects persisted to 6-month follow-up.The study was registered at Clinical Trials.gov (NCT02095197).

Evaluation of anxiety in procedure-naive patients during cervical and lumbar epidural steroid injection procedures.

BACKGROUND AND OBJECTIVES: The lack of studies that identify patient and procedural risk factors for increased levels of anxiety during spine injections represents a major barrier to the development of safe tailored sedation practices. We measured and compared anxiety in procedure-naive patients undergoing a cervical or lumbar interlaminar epidural steroid injection to identify predictors of patient movement and vasovagal responses in the periprocedural period. METHODS: This prospective observational cohort study was conducted with injection-naive patients presenting for a routine cervical or lumbar epidural steroid injection. The primary outcome measure was the Spielberger State Trait Anxiety Inventory (STAI) score. Participants also reported anxiety using the Numeric Rating Scale in the periprocedural period. The Wilcoxon rank sum test was used to compare STAI scores; Numeric Rating Scale values were compared using Friedman test. Post hoc tests were corrected for 12 comparisons using the Bonferroni method. RESULTS: We found no group differences in age, gender, marital status, Visual Analog Scale pain score, duration of pain symptoms, or utilization of health care resources for pain symptom management. The mean STAI score was 43 ± 8 in the cervical group (n = 140) and 44 ± 9 in the lumbar group (n = 140) (P = 0.35), a low level of anxiety. There were no between-group differences in anxiety at any point during the periprocedural period. A vasovagal response was identified in 10% of the cervical group and in 3% of the lumbar group (P = 0.04). CONCLUSIONS: No group differences in anxiety were seen between cervical and lumbar groups. Anxiety levels were not associated with patient movement or vasovagal symptoms. Our results suggest that the practice of routine prevention or treatment of injection-related anxiety in the procedure-naive general population with a duration of pain less than 6 months and without a history of an anxiety disorder should be reevaluated.

Indene bioconversion by a toluene inducible dioxygenase of Rhodococcus sp. I24.

Rhodococcus sp. I24 can oxygenate indene via at least three independent enzyme activities: (i) a naphthalene inducible monooxygenase (ii) a naphthalene inducible dioxygenase, and (iii) a toluene inducible dioxygenase (TID). Pulsed field gel analysis revealed that the I24 strain harbors two megaplasmids of approximately 340 and approximately 50 kb. Rhodococcus sp. KY1, a derivative of the I24 strain, lacks the approximately 340 kb element as well as the TID activity. Southern blotting and sequence analysis of an indigogenic, I24-derived cosmid suggested that an operon encoding a TID resides on the approximately 340 kb element. Expression of the tid operon was induced by toluene but not by naphthalene. In contrast, naphthalene did induce expression of the nid operon, encoding the naphthalene dioxygenase in I24. Cell free protein extracts of Escherichia coli cells expressing tidABCD were used in HPLC-based enzyme assays to characterize the indene bioconversion of TID in vitro. In addition to 1-indenol, indene was transformed to cis-indandiol with an enantiomeric excess of 45.2% of cis-(1S,2R)-indandiol over cis-(1R,2S)-indandiol, as revealed by chiral HPLC analysis. The Km of TID for indene was 380 microM. The enzyme also dioxygenated naphthalene to cis-dihydronaphthalenediol with an activity of 78% compared to the formation of cis-indandiol from indene. The Km of TID for naphthalene was 28 microM. TID converted only trace amounts of toluene to 1,2-dihydro-3-methylcatechol after prolonged incubation time. The results indicate the role of the tid operon in the bioconversion of indene to 1-indenol and cis-(1S,2R)-indandiol by Rhodococcus sp. I24.