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STUDY DESIGN: This is a retrospective, observational study.INTRODUCTION: Spinal cord stimulation (SCS) has found its application in chronic pain treatment, with failed back surgery syndrome (FBSS) as one of the most important indications. However, to date, little is known about the long-term effectiveness of the treatment. The aim of this study is to analyze retrospectively the long-term outcomes of SCS treatment in a single multidisciplinary pain center on predominant radicular pain, using devices of a single manufacturer.MATERIALS AND METHODS: Patient data on overall patient satisfaction, pain intensity, and adverse events were retrospectively collected in our clinical practice between January 1998 and January 2018, for 191 patients who received a permanent SCS implant. Secondary health measures included the influence of opioid and nicotine use on pain reduction after therapy.RESULTS: The trial-to-implant ratio was 93.6%. At a mean follow-up of 10.6 years, 78.5% of the patients were satisfied with the treatment outcome, with a significant pain reduction of an average three points on a Numeric Rating Scale. Opioid and nicotine usage did not have a significant link with the pain reduction one year after the treatment. Furthermore, devices had an average battery lifespan of 8.4 years. A total of 248 revisions were recorded. A total of 24 patients (11.7%) acquired an infection; 7 of 204 patients had an infection during the trial period, 2 of 191 patients had an infection in the first postoperative year, and 15 of 191 patients had an infection after the first year. The average time to infection, if not in the first year, was 10.1 years.CONCLUSIONS: A successful long-term outcome regarding pain relief in patients with predominant radicular pain due to FBSS is established with SCS therapy.

BackgroundRadiofrequency (RF) treatment of the genicular nerves has the potential to reduce chronic knee pain due to osteoarthritis or persistent postsurgical pain, however, a direct comparison between the two main modalities used, conventional and cooled, is lacking.MethodsThis double blind, non-inferiority, pilot, randomized controlled trial compared the effects of cooled and conventional RF in chronic knee pain patients suffering from osteoarthritis or persistent postsurgical pain after total knee arthroplasty. Patients were randomized following a 1:1 rate. The primary outcome was the proportion of patients with ≥50% pain reduction at 3 months postintervention. Other outcomes were knee pain, functionality, quality of life, emotional health, and adverse events up to 6 months postintervention. Conventional RF treatment was tested for non-inferiority to cooled in reducing knee pain at 3 months follow-up.ResultsForty-nine of 70 patients were included, of which 47 completed a 3-month follow-up. The primary outcome was achieved in 4 of 23 patients treated with conventional RF (17%) vs in 8 of 24 with cooled (33%) (p=0,21). Results from the non-inferiority comparison were inconclusive in relation to the non-inferiority margin. There was no statistically significant difference between secondary outcomes. There were no serious adverse events.ConclusionsBoth conventional and cooled RF treatment reduced pain in the osteoarthritis and persistent postsurgical pain population. This pilot study did not demonstrate statistically significant differences in the proportion of patients experiencing ≥50% pain reduction between techniques. The non-inferiority analysis was inconclusive. These results warrant further research.Trial registration numberNCT03865849.

BackgroundThe innervation of the sacroiliac joint (SIJ) is complex, with a dual innervation originating from the lumbosacral plexus anteriorly as well as the sacral lateral branches posteriorly. Nociceptors are found in intra-articular structures as well as periarticular structures. In patients with SIJ pain, a fluoroscopy-guided SIJ injection is usually performed posteriorly into the bottom one-third of the joint with local anesthetic and corticosteroids, but this does not always reach all intra-articular structures. The correlation between a cranial contrast spread and clinical success is undetermined in patients with SIJ pain.MethodsIn a tertiary referral pain center, electronic medical records of patients who underwent an SIJ injection were retrospectively analyzed. Only patients with at least three positive provocation maneuvers for SIJ pain were selected. Contrast images of the SIJ were classified as with or without cranial spread on fluoroscopy as a marker of intra-articular injection. Clinical success was defined as ≥50% improvement in the patient’s global perceived effect after 3–4 weeks. The primary outcome was defined as the correlation between cranial contrast spread and clinical success after an SIJ injection.Results128 patients in total were included. In 68 patients (53.1%) fluoroscopy showed cranial contrast spread. Clinical success was higher in patients with cranial spread of contrast (55 of 68, 81%) versus those without (35 of 60, 58%) (p=0.0067). In a multivariable analysis with age, gender, presence of rheumatoid arthritis, side, and number of positive provocation maneuvers, the cranial spread of contrast remained the only independent factor of clinical success (p=0.006; OR 3.2, 95% CI 1.4 to 7.7).ConclusionIn patients with SIJ pain, identified by positive pain provocation maneuvers, cranial contrast spread as a marker of intra-articular injection, with subsequent injection of 3 mL of local anesthetic and methylprednisolone 40 mg, was significantly correlated with clinical success up to 4 weeks. Therefore, attempts should be made to reach this final needle position before injecting local anesthetic and corticosteroids. This result needs to be confirmed in a high-quality prospective trial.

Background. In a previous prospective study on pulsed radiofrequency (PRF) treatment adjacent to the lumbar dorsal root ganglion (DRG) for patients with chronic lumbosacral radicular pain, we reported success in 55.4% of the patients at 6 months. Identification of predictors for success after PRF may improve outcome. We assessed the predictors of PRF in patients with chronic intractable lumbosacral radicular pain. Methods. Patients with monosegmental chronic lumbosacral radicular pain of L5 or S1 first received a selective nerve root block at the corresponding level. Independent of the result of this block a PRF treatment at the same level was performed. At 6 weeks, 3 months, and 6 months after the procedure the outcome was evaluated. Results. A positive diagnostic nerve root block and age a parts per thousand yen 55 were predictive factors for successful outcome at 6 months, while disability was a negative predictor. The use of failed back surgery syndrome, gender, duration of pain, Numerical Rating Scale, level and side of treatment, DN4, and RAND-36 as predictors for success was not supported. Conclusions. Successful outcome after PRF adjacent to the DRG, in patients with intractable chronic lumbosacral radicular pain, is more likely in patients a parts per thousand yen 55 years, with limited disability and after a positive diagnostic nerve root block. A combination of all these factors creates a fair predictive value (AUC: 0.73).

Department of Anesthesiology, Critical Care and Mul-tidisciplinary Pain Center, ZOL, Genk, BelgiumReprint requests to: Koen Van Boxem, MD, PhD, FIPP,Department of Anesthesiology Critical Care and Multi-disciplinary Pain Center, Sint Jozefkliniek, Bornem enWillebroek, Kasteelstraat 23, 2880 Bornem, Belgium.Tel: 132 3 890 16 94; Fax: 132 3 890 59 23; E-mail:dr.Van.Boxem@sjk.be.Conflict of interest: None of the authors have a conflictof interest.Funding sources: The work has been performed incollaboration between all the authors, without anyfinancial support.AbstractBackground and Objectives. There is little evidenceconcerning the medical management of lumbosacralradicular pain. The prognosis for patients sufferingpain for more than 3 months is poor. Pulsed radiofre-quency (PRF) treatment of the dorsal root ganglion(DRG) has been suggested as a minimally invasivetreatment. We studied the effect on pain and qualityof life of PRF treatment of the DRG in patients withchronic, severe lumbosacral radicular pain.Methods. Patients with lumbosacral radicular painwere screened to select a homogeneous popula-tion. PRF treatment of the DRG was performed at L5or S1. Evaluation was carried out at 6 weeks,3 months, and 6 months. Pain reduction and “fullyrecovered” or “much improvement,” in terms of theglobal perceived effect, were the primary outcomes.Quality of life (RAND-36), disability (Oswestry Dis-ability Index), and the neuropathic pain scales leedsassessment of neuropathic symptoms and signs(LANSS) and DN4 were registered at each timepoint. Medication use was scored with the Medica-tion Quantification Scale.Results. Out of 461 screened patients, 65 wereincluded. According to the intention to treat analy-sis, clinical success was achieved in 56.9%, 52.3%,and 55.4% of the patients at respectively 6 weeks,3 months, and 6 months. DN4, Oswestry DisabilityIndex and physical component for the RAND-36qualityof life improved significantly while the mentalcomponent remained unchanged. The number ofpatients on opioids was reduced.Conclusions. PRF treatment of the DRG may beconsidered for patients with chronic, severe lumbo-sacral radicular pain refractory to conventionalmedical management.Key Words. Radiofrequency; Lumbosacral radicu-lar pain; Pulsed radiofrequency; Dorsal root gan-glion; Conventional Medical ManagementIntroductionLumbosacral radicular (LRS) pain is an important healthcare problem. In the general, population older than 30years of age, up to 5% suffer low back pain radiating1

Radicular pain is an important health care problem, with only limited evidence-based treatments available. Treatment selection should ideally target documented pathophysiological pathways. In herniated discs, a sequence in the inflammatory cascade can be observed that initiates and maintains increased nociceptive signal input. Inflammatory mediators including tumor necrosis factor α are released from the nucleus pulposus and the degenerating peripheral nerve, which, in turn, induces production of neurotrophins like nerve growth factor and brain-derived neurotrophic factor. Neurotrophins interfere not only with the generation of ectopic firing of nociceptive neurons in the dorsal root ganglion but also with the excitability and sensitization of neuronal transmission in the dorsal spinal horn. Radicular pain is further characterized by the electrophysiological spreading of the afferent nociceptive input over different spinal nerve roots. Both the complex pathophysiological pathways involved and the spreading of the nociceptive signal make radicular pain difficult to treat. Pulsed radiofrequency (PRF) is considered an option in treatment of radicular pain. To understand and increase the efficiency of PRF interventional treatments in radicular pain, both in vitro and in vivo studies aiming at elucidating part of the mechanism of action of PRF are described. Potential factors that may improve the efficacy of PRF treatment in radicular pain are discussed.

SUMMARY Low back pain is one of the most prominent healthcare problems but there is no gold standard for its diagnosis. Aspecific low back pain can be subdivided into radicular and mechanical pain. The diagnosis mainly relies on a combination of elements, such as medical history, physical examination, medical imaging and other possible additional tests. Once a working diagnosis has been established, confirmation of the causative structure and level is sought by means of diagnostic blocks. The use of the different diagnostic tests and blocks should be guided by the balance between the potential benefit (mainly in terms of improved treatment outcome, the possible burden for the patient and the chances of withholding potential effective treatment to patients) with false-negative test results.

Dear Editor, Drs. Freo and Calldero rightfully issued a remark on our odds analysis of the factors predictive for the positive outcome of a pulsed radio frequency (PRF) treatment adjacent to the lumbar dorsal root ganglion. We have to admit that the negative value of the odds ratio is a typographic error. We checked the output of the analysis and the odds ratios should be +0.97 and +0.96. The statistical threshold of 0.1 is quite common; values of 0.15 and 0.2 are also used, …

Background and ObjectivesThe usefulness of adding bupivacaine to an opioid administered by the epidural route is controversial. This study examines both the quality of pain relief and side effects, in particular urinary retention, during patient-controlled epidural analgesia (PCEA) with sufentanil alone or in combination with two different concentrations of bupivacaine.MethodsIn a double-blind randomized study, 60 healthy young adults undergoing open knee or ankle surgery with combined spinal-epidural anesthesia received postoperative analgesia via PCEA with sufentanil alone or with 0.06% or 0.12% bupivacaine. In addition to pain scores at rest and during mobilization, bladder function was evaluated. Strict criteria were respected in scoring the occurrence of problems suggestive of urinary retention. The 24-hour analgesic consumption and the incidence of other side effects were also recorded.ResultsPatients receiving bupivacaine had better pain relief than those receiving only the opioid, but this difference was more pronounced when measuring dynamic pain scores. The consumption of sufentanil was significantly higher in the group receiving the opioid alone than in the group receiving 0.06% bupivacaine. The bupivacaine dose requirements were twice as high with the 0.12% concentration. Bladder problems occurred significantly more frequently in patients treated with the highest bupivacaine concentration. Motor impairment was not a major problem.ConclusionsA 0.06% bupivacaine-sufentanil combination offered the best results in terms of analgesic quality and lower side effects, mainly micturition problems, which may be explained by the higher consumption of local anesthetic at the higher bupivacaine concentration. Analgesic quality could not be improved by increasing the bupivacaine concentration.

Dear Editor, We thank Dr. Bhatia for asking for some clarification on our study design and interpretation of a 6-month cohort study on PRF related to chronic intractable radicular pain [1]. 1. The maintenance and flexibility of conventional medical management are dictated by ethical and practical considerations. Patients presenting in a pain clinic have already received several types of conventional medical management that may consist of tramadol, amitryptilin, gabapentin, or pregabalin. Stopping this treatment to allow only, for example, tramadol as an escape medication is not justifiable from an ethical point of view when performing a study with a follow-up period of 6 months or longer. There is currently no evidence on the efficacy of any medication in the treatment of lumbasacral radicular pain [2], which made it even …