Double-blind, randomized, controlled, crossover trial of pregabalin for neurogenic claudication

Predictors of success of pharmacological management in patients with chronic lower back pain: systematic review

BACKGROUND

Conservative management is recommended as the first therapeutic step in chronic low back pain (LBP), but there is no available evidence regarding the possible effect of patients' baseline characteristics on the therapeutic outcomes. A systematic review of the literature was performed to investigate this point.

METHODS

In February 2024, all the level I studies investigating the role of pharmacological management for chronic LBP were accessed. Data concerning the patient demographic at baseline were collected: number of patients and related mean BMI and age, duration of the symptoms, duration of the follow-up, percentage of females, Numeric Rating Scale (NRS), the Roland Morris Disability Questionnaire (RMQ), Oswestry Disability Index (ODI). The outcomes at the last follow-up were evaluated through NRS, RMQ, and ODI. A multiple linear model regression diagnostic through the Pearson Product-Moment Correlation Coefficient (r) was used.

RESULTS

Data from 47 articles (9007 patients) were obtained. The analysis yielded the following significant associations: age at baseline and NRS at follow-up (r = - 0.22; P = 0.04), NRS at baseline with NRS (r = 0.26; P = 0.03) and RMQ (r = - 0.58; P = 0.02) at follow-up, RMQ at baseline and the same at follow-up (r = 0.69; P = 0.0001).

CONCLUSION

Older age, higher BMI, presence of comorbidities, higher ODI and a long history of symptoms or surgical treatments do not reduce the efficacy of pharmacological management of chronic LBP. However, pharmacological therapy is not an effective option for patients with high baseline RMQ.

LEVEL OF EVIDENCE

I systematic review of RCTs.

Management of lumbar spinal stenosis: a systematic review and meta-analysis of rehabilitation, surgical, injection, and medication interventions

BACKGROUND

Lumbar spinal stenosis (LSS) has a substantial impact on mobility, autonomy, and quality of life. Previous reviews have demonstrated inconsistent results and/or have not delineated between specific nonsurgical interventions.

OBJECTIVE

The purpose of this systematic review is to assess the effectiveness of interventions in the management of LSS.

METHODS

Eligible studies were randomized controlled trials (RCTs) or prospective studies, included patients with LSS, assessed the effectiveness of any interventions (rehabilitation, surgical, injection, medication), included at least two intervention groups, and included at least one measure of pain, disability, ambulation assessment, or LSS-specific symptoms. Eighty-five articles met inclusion criteria. Meta-analyses were conducted across outcomes. Effect sizes were calculated using Hedge's g and reported descriptively. Formal grading of evidence was conducted.

RESULTS

Meta-analysis comparing rehabilitation to no treatment/placebo demonstrated significant effects on pain favoring rehabilitation (mean difference, MD -1.63; 95% CI: -2.68, -0.57; I² = 71%; p = .002). All other comparisons to no treatment/placebo revealed nonsignificant findings. The level of evidence ranged from very low to high for rehabilitation and medication versus no treatment/placebo for pain, disability, ambulation ability, and LSS symptoms.

CONCLUSIONS

Although the findings of this review are inconclusive regarding superiority of interventions, this accentuates the value of multimodal patient-centered care in the management of patients with LSS.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Efficacy and Safety of Add-on Mirogabalin to NSAIDs in Lumbar Spinal Stenosis with Peripheral Neuropathic Pain: A Randomized, Open-Label Study

Introduction

In Japan, conservative therapy for patients with lumbar spinal stenosis (LSS) includes non-steroidal anti-inflammatory drugs (NSAIDs), prostaglandin E1, tramadol, physical/exercise therapy, and nerve blocks. Mirogabalin, a selective oral α2δ ligand, is approved for treating peripheral neuropathic pain, though data regarding visual analog scores (VAS) for pain in patients with LSS are limited. We investigated the efficacy and safety of mirogabalin as an add-on treatment in patients with LSS taking NSAIDs compared with patients taking NSAIDs only.

Methods

This multicenter, randomized, open-label study (MiroTAS) was conducted at 32 centers in Japan between June 2020 and October 2021. Patients were randomly assigned to mirogabalin and NSAIDs or NSAIDs alone in a 1:1 ratio. NSAIDs were administered according to their Japanese package inserts; mirogabalin was administered based on renal function [creatinine clearance (CrCL) ≥ 60 mL/min, 5 mg twice daily (BID) in Weeks 1–2, 10 mg BID in Weeks 3–4, and 15 or 10 mg BID after Week 5; CrCL 30 to < 60 mL/min, 2.5 mg BID Weeks 1–2, 5 mg BID Weeks 3–4, and 7.5 or 5 mg BID after Week 5]. The primary endpoint was the change in VAS score for leg pain from baseline to Week 12. Secondary endpoints were quality of life, evaluated using the EuroQol five-dimensional descriptive system (EQ-5D-5L) (at baseline and Week 12) and Patient Global Impression of Change (PGIC) (at Week 12), and safety. Change in VAS score at Week 12 was calculated using a linear mixed model for repeated measures. The safety endpoints were treatment-emergent adverse events (TEAEs) and adverse drug reactions.

Results

In total, 220 patients who met the eligibility criteria were enrolled. In the mirogabalin and NSAIDs and NSAIDs groups, mean ages (67.8 vs. 70.9 years), proportions of female patients (54.5% vs. 49.0%), mean body weights (63.9 vs. 62.0 kg), mean CrCL values (81.5 vs. 70.7 mL/min), proportions of patients with CrCL 30 to < 60 mL/min (27.3% vs. 33.7%), mean VAS scores (63.8 vs. 62.8 mm), and proportions of patients with VAS score ≥ 60 (53.6% vs. 52.9%) at enrollment were similar. The median durations of LSS were 9.0 and 11.0 months and the spine pain DETECT questionnaire (SPDQ) scores were 6.8 and 7.8, respectively. The least square (LS) mean change in VAS score from baseline to Week 12 was − 24.1 mm in the mirogabalin and NSAIDs group and − 14.2 mm in the NSAIDs group (both P < 0.0001 vs. baseline). The difference in LS mean was − 9.9 [95% confidence interval (CI), − 18.0, − 1.8] (P = 0.0174). The improvement in EQ-5D-5L score at Week 12 was significantly greater in the mirogabalin and NSAIDs group versus the NSAIDs group [mean difference, 0.0529 (95% CI, 0.0036, 0.1022), P = 0.0357]. At Week 12, the proportions of patients with PGIC scores ≤ 3 and ≤ 2 were higher in the mirogabalin and NSAIDs group vs. the NSAIDs group (76.2% vs. 50.0%, P = 0.0006, and 47.6% vs. 32.4%, P = 0.0523). In the mirogabalin and NSAIDs group, the incidences of TEAEs and adverse drug reactions were 60.9% and 57.3%, respectively, and the most common TEAEs were somnolence (30.0%) and dizziness (25.5%).

Conclusions

The addition of mirogabalin to NSAIDs improved VAS, EQ-5D-5L, and PGIC. The main TEAEs were somnolence and dizziness. The addition of mirogabalin to NSAIDs improved peripheral neuropathic pain associated with LSS and raised no new safety concerns.

Trial Registration

Japan Registry of Clinical Trials (jRCTs021200007).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-022-00410-z.

Pharmacotherapy for Spine-Related Pain in Older Adults

As the population ages, spine-related pain is increasingly common in older adults. While medications play an important role in pain management, their use has limitations in geriatric patients due to reduced liver and renal function, comorbid medical problems, and polypharmacy. This review will assess the evidence basis for medications used for spine-related pain in older adults, with a focus on drug metabolism and adverse drug reactions. A PubMed/OVID search crossing common spine, neck, and back pain terms with key words for older adults and geriatrics was combined with common drug classes and common drug names and limited to clinical trials and age over 65 years. The results were then reviewed with identification of commonly used drugs and drug categories: nonsteroidal anti-inflammatories (NSAIDs), acetaminophen, corticosteroids, gabapentin and pregabalin, antispastic and antispasmodic muscle relaxants, tricyclic antidepressants (TCAs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tramadol, and opioids. Collectively, 138 double-blind, placebo-controlled trials were the focus of the review. The review found a variable contribution of high-quality studies examining the efficacy of medications for spine pain primarily in the geriatric population. There was strong evidence for NSAID use with adjustments for gastrointestinal and renal risk factors. Gabapentin and pregabalin had mixed evidence for neuropathic pain. SNRIs had good evidence for neuropathic pain and a more favorable safety profile than TCAs. Tramadol had some evidence in older patients, but more so in persons aged < 65 years. Rational therapeutic choices based on geriatric spine pain diagnosis are helpful, such as NSAIDs and acetaminophen for arthritic and myofascial-based pain, gabapentinoids or duloxetine for neuropathic and radicular pain, antispastic agents for myofascial-based pain, and combination therapy for mixed etiologies. Tramadol can be well tolerated in older patients, but has risks of cognitive and classic opioid side effects. Otherwise, opioids are typically avoided in the treatment of spine-related pain in older adults due to their morbidity and mortality risk and are reserved for refractory severe pain. Whenever possible, beneficial geriatric spine pain pharmacotherapy should employ the lowest therapeutic doses with consideration of polypharmacy, potentially decreased renal and hepatic metabolism, and co-morbid medical disorders.

Non-operative treatment for lumbar spinal stenosis with neurogenic claudication: an updated systematic review

OBJECTIVES

Neurogenic claudication due to lumbar spinal stenosis (LSS) is a growing health problem in older adults. We updated our previous Cochrane review (2013) to determine the effectiveness of non-operative treatment of LSS with neurogenic claudication.

DESIGN

A systematic review.

DATA SOURCES

CENTRAL, MEDLINE, EMBASE, CINAHL and Index to Chiropractic Literature databases were searched and updated up to 22 July 2020.

ELIGIBILITY CRITERIA

We only included randomised controlled trials published in English where at least one arm provided data on non-operative treatment and included participants diagnosed with neurogenic claudication with imaging confirmed LSS.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed risk of bias using the Cochrane Risk of Bias Tool 1. Grading of Recommendations Assessment, Development and Evaluation was used for evidence synthesis.

RESULTS

Of 15 200 citations screened, 156 were assessed and 23 new trials were identified. There is moderate-quality evidence from three trials that: Manual therapy and exercise provides superior and clinically important short-term improvement in symptoms and function compared with medical care or community-based group exercise; manual therapy, education and exercise delivered using a cognitive-behavioural approach demonstrates superior and clinically important improvements in walking distance in the immediate to long term compared with self-directed home exercises and glucocorticoid plus lidocaine injection is more effective than lidocaine alone in improving statistical, but not clinically important improvements in pain and function in the short term. The remaining 20 new trials demonstrated low-quality or very low-quality evidence for all comparisons and outcomes, like the findings of our original review.

CONCLUSIONS

There is moderate-quality evidence that a multimodal approach which includes manual therapy and exercise, with or without education, is an effective treatment and that epidural steroids are not effective for the management of LSS with neurogenic claudication. All other non-operative interventions provided insufficient quality evidence to make conclusions on their effectiveness.

PROSPERO REGISTRATION NUMBER

CRD42020191860.

Jmjd3 Mediates Neuropathic Pain by Inducing Macrophage Infiltration and Activation in Lumbar Spinal Stenosis Animal Model

Lumbar spinal stenosis (LSS) is a major cause of chronic neuropathic back and/or leg pain. Recently, we demonstrated that a significant number of macrophages infiltrated into the cauda equina after compression injury, causing neuroinflammation, and consequently mediating neuropathic pain development and/or maintenance. However, the molecular mechanisms underlying macrophage infiltration and activation have not been elucidated. Here, we demonstrated the critical role of histone H3K27 demethylase Jmjd3 in blood-nerve barrier dysfunction following macrophage infiltration and activation in LSS rats. The LSS rat model was induced by cauda equina compression using a silicone block within the epidural spaces of the L5-L6 vertebrae with neuropathic pain developing 4 weeks after compression. We found that Jmjd3 was induced in the blood vessels and infiltrated macrophages in a rat model of neuropathic pain. The blood-nerve barrier permeability in the cauda equina was increased after compression and significantly attenuated by the Jmjd3 demethylase inhibitor, GSK-J4. GSK-J4 also inhibited the expression and activation of MMP-2 and MMP-9 and significantly alleviated the loss of tight junction proteins and macrophage infiltration. Furthermore, the activation of a macrophage cell line, RAW 264.7, by LPS was significantly alleviated by GSK-J4. Finally, GSK-J4 and a potential Jmjd3 inhibitor, gallic acid, significantly inhibited mechanical allodynia in LSS rats. Thus, our findings suggest that Jmjd3 mediates neuropathic pain development and maintenance by inducing macrophage infiltration and activation after cauda equina compression and thus may serve as a potential therapeutic target for LSS-induced neuropathic pain.

A systematic review and meta-analysis of the effectiveness and adverse events of gabapentin and pregabalin for sciatica pain

Aim

This SR aims to assess the effectiveness of pregabalin and gabapentin on pain and disability caused by acute sciatica and the adverse events associated with their clinical use.

Design

Systematic review.

Databases

Electronic databases of Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Clinical Trials.gov were searched from their inception until March 1st of 2021.

Selection criteria

Randomized trials (RCT) with adults > 18 years old with acute sciatica for a minimum of 1 week and a maximum of 1 year (at least moderate pain).

Data treatment

The outcomes were pain, disability and adverse events. Data was summarized using odds ratio and mean difference. GRADE was used to calculate the level of evidence.

Results

Eight RCT involving 747 participants were included. The effect of pregabalin was assessed in 3 RCT and in one three-arm trial (pregabalin vs limaprost vs a combination of limaprost and pregabalin). Two trials assessed the effect of gabapentin compared with placebo and one compared with tramadol. One study assessed the effect of gabapentin vs pregabalin in a crossover head-to-head trial.

A statistically significant improvement on leg pain at 2 weeks and leg pain with movement at 3 and 4 months was found in a RCT comparing gabapentin with placebo. There were no statistically differences on the remaining time periods assessed for leg pain, low back pain and functional disability.

Conclusions

This SR provides clear evidence for lack of effectiveness of pregabalin and gabapentin for sciatica pain management. In view of this, its routine clinical use cannot be supported.

Non-Surgical Interventions for Lumbar Spinal Stenosis Leading To Neurogenic Claudication: A Clinical Practice Guideline

Lumbar spinal stenosis (LSS) causing neurogenic claudication (NC) is increasingly common with an aging population and can be associated with significant symptoms and functional limitations. We developed this guideline to present the evidence and provide clinical recommendations on nonsurgical management of patients with LSS causing NC. Using the GRADE approach, a multidisciplinary guidelines panel based recommendations on evidence from a systematic review of randomized controlled trials and systematic reviews published through June 2019, or expert consensus. The literature monitored up to October 2020. Clinical outcomes evaluated included pain, disability, quality of life, and walking capacity. The target audience for this guideline includes all clinicians, and the target patient population includes adults with LSS (congenital and/or acquired, lateral recess or central canal, with or without low back pain, with or without spondylolisthesis) causing NC. The guidelines panel developed 6 recommendations based on randomized controlled trials and 5 others based on professional consensus, summarized in 3 overarching recommendations: (Grade: statements are all conditional/weak recommendations) Recommendation 1. For patients with LSS causing NC, clinicians and patients may initially select multimodal care nonpharmacological therapies with education, advice and lifestyle changes, behavioral change techniques in conjunction with home exercise, manual therapy, and/or rehabilitation (moderate-quality evidence), traditional acupuncture on a trial basis (very low-quality evidence), and postoperative rehabilitation (supervised program of exercises and/or educational materials encouraging activity) with cognitive-behavioral therapy 12 weeks postsurgery (low-quality evidence). Recommendation 2. In patients LSS causing NC, clinicians and patients may consider a trial of serotonin-norepinephrine reuptake inhibitors or tricyclic antidepressants. (very low-quality evidence). Recommendation 3. For patients LSS causing NC, we recommend against the use of the following pharmacological therapies: nonsteroidal anti-inflammatory drugs, methylcobalamin, calcitonin, paracetamol, opioids, muscle relaxants, pregabalin (consensus-based), gabapentin (very low-quality), and epidural steroidal injections (high-quality evidence). PERSPECTIVE: This guideline, on the basis of a systematic review of the evidence on the nonsurgical management of lumbar spine stenosis, provides recommendations developed by a multidisciplinary expert panel. Safe and effective non-surgical management of lumbar spine stenosis should be on the basis of a plan of care tailored to the individual and the type of treatment involved, and multimodal care is recommended in most situations.

Urinary side effects of psychotropic drugs: A systematic review and metanalysis

OBJECTIVE

To evaluate the effects of psychotropic drugs on bladder function.

MATERIALS AND METHODS

A systematic review was carried out by searching PubMed and Embase databases for randomized controlled trials enrolling patients treated with psychotropic drugs with available information on treatment-related urinary disorders.

RESULTS

A total of 52 studies was selected. In antidepressant therapy, bladder voiding symptoms, rather than storage symptoms, were more frequently observed. Pooled analysis demonstrated a higher odds ratio (OR) of voiding  disorders in comparison with placebo (OR: 3.30; confidence interval [CI]: 1.90-5.72; 7856 participants; p < 0.001). Odds for voiding dysfunction was higher for tricyclic antidepressants and for Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs) when compared to Selective Serotonin Reuptake Inhibitors (SSRIs). Treatment with antipsychotics was associated with heterogeneous urinary disorders  including emptying and storage disorders. OR for incontinence in patients with dementia taking  antipsychotics was higher than placebo (OR: 4.09; CI: 1.71-9.79, p = 0.002) with no difference between different atypical antipsychotics. Rate of voiding disorders was not different between conventional and atypical antipsychotics (OR: 1.64; CI: 0.79-3.39, p = 0.19), although quetiapine showed higher odds to cause voiding dysfunction than other atypical antipsychotics (OR: 2.14; CI: 1.41-3.26; p > 0.001).

CONCLUSIONS

In patients taking tricyclic antidepressants or SNRIs, bladder voiding disorders, could be the side effects of therapy rather than symptoms of a urological disease. Patients treated with these drugs should be actively monitored for the appearance of urinary symptoms. Antipsychotic treatment is associated with various urinary side effects requiring a tailored approach.

Effectiveness of Pregabalin Treatment for Neuropathic Pain in Patients with Spine Diseases: A Pooled Analysis of Two Multicenter Observational Studies in Japan

Purpose

Neuropathic pain (NeP) is common among patients with chronic pain associated with spine diseases. Practical effectiveness of pregabalin, one of the first-line treatments for NeP, has not been evaluated in an entire population of patients with spine diseases, including various pathophysiological conditions. This pooled analysis aimed to evaluate the therapeutic value of pregabalin for chronic pain with NeP component in patients with spine diseases in routine primary care settings.

Patients and Methods

We pooled data from two 8-week prospective observational cohort studies for patients with chronic low back pain with accompanying lower limb pain (NeP component), and patients with chronic cervical pain and accompanying upper limb radiating pain (NeP component) in routine primary care settings in Japan. For both studies, patients were treated for 8 weeks with pregabalin (alone/with other analgesics) or usual care with conventional analgesics (eg, non-steroidal anti-inflammatory drugs). Changes in pain numerical rating scale (NRS), Pain-Related Sleep Interference Scale (PRSIS), and EuroQol 5-dimension 5-level (EQ-5D-5L) scores from baseline to week 8 were summarized and compared between the pregabalin and usual care groups, and also for subgroups of primary diagnosis. Safety was evaluated by adverse events (AEs) in the pregabalin group.

Results

The pooled dataset comprised 700 patients (pregabalin group: 302; usual care group: 398). All patient-reported outcomes (PRO) scores significantly improved from baseline to week 8 in the pregabalin than in the usual care group (NRS: P<0.0001; PRSIS: P<0.0001, and EQ-5D-5L: P=0.0006). Overall, all three PRO measures showed greater improvement in the pregabalin than in the usual care group, irrespective of the primary diagnosis. AEs were reported in 36.1% of the pregabalin group.

Conclusion

This analysis suggested multi-faceted effectiveness of treatment with pregabalin from the patient’s perspectives under a “real-world” practice in all patients with chronic NeP from various spine diseases.

A New Method for Imputing Censored Values in Crossover Designs with Time-to-Event Outcomes Using Median Residual Life

Crossover designs are commonly applied in research due to efficiency and subject parsimony compared to parallel studies. Baseline measurements would improve the power of comparison. For time to event outcomes, the sample size is reduced due to censorship, if they are ignored; thus, applying traditional regression models will be limited. A logical solution is to impute the censored observation and apply common analytical models for analyzing the data. Nevertheless, techniques to impute censored data in time-to-event outcomes in crossover designs are not practiced as much. Accordingly, we propose a method to impute the censored observation using median residual life regression and then analyze the data using analyses of covariance (ANCOVA), considering the difference of period-specific baselines as covariate. We used simulation to show the favorable performance of our method relative to a recently proposed method, multiple imputation with model averaging and ANCOVA (MI^MI). Specifically, the censored observations were multiply-imputed using prespecified parametric event time models, and then, the methods were applied to a real data example.

Preoperative Factors Predict Postoperative Trajectories of Pain and Disability Following Surgery for Degenerative Lumbar Spinal Stenosis

STUDY DESIGN

Longitudinal analysis of prospectively collected data.

OBJECTIVE

Investigate potential predictors of poor outcome following surgery for degenerative lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

LSS is the most common reason for an older person to undergo spinal surgery, yet little information is available to inform patient selection.

METHODS

We recruited LSS surgical candidates from 13 orthopedic and neurological surgery centers. Potential outcome predictors included demographic, health, clinical, and surgery-related variables. Outcome measures were leg and back numeric pain rating scales and Oswestry disability index scores obtained before surgery and after 3, 12, and 24 postoperative months. We classified surgical outcomes based on trajectories of leg pain and a composite measure of overall outcome (leg pain, back pain, and disability).

RESULTS

Data from 529 patients (mean [SD] age = 66.5 [9.1] yrs; 46% female) were included. In total, 36.1% and 27.6% of patients were classified as experiencing a poor leg pain outcome and overall outcome, respectively. For both outcomes, patients receiving compensation or with depression/depression risk were more likely, and patients participating in regular exercise were less likely to have poor outcomes. Lower health-related quality of life, previous spine surgery, and preoperative anticonvulsant medication use were associated with poor leg pain outcome. Patients with ASA scores more than two, greater preoperative disability, and longer pain duration or surgical waits were more likely to have a poor overall outcome. Patients who received preoperative chiropractic or physiotherapy treatment were less likely to report a poor overall outcome. Multivariable models demonstrated poor-to acceptable (leg pain) and excellent (overall outcome) discrimination.

CONCLUSION

Approximately one in three patients with LSS experience a poor clinical outcome consistent with surgical non-response. Demographic, health, and clinical factors were more predictive of clinical outcome than surgery-related factors. These predictors may assist surgeons with patient selection and inform shared decision-making for patients with symptomatic LSS.

LEVEL OF EVIDENCE

2.

The pharmacological management of chronic lower back pain

INTRODUCTION

Treating chronic low back pain (LBP) can be challenging, and the most effective pharmacological therapy is controversial. The present systematic review investigated the efficacy of various pharmacological compounds to achieve pain relief and improve disability in chronic LBP patients. The present study focused on acetaminophen, amoxicillin, flupirtine, baclofen, tryciclic antidepressants (TCAs), duloxetine, topiramate, gabapentinoids, non-steroid anti-inflammatory drugs (NSAIDs) and opioids.

AREAS COVERED

All randomized clinical trials comparing two or more drug treatments for chronic low back pain were accessed. Studies reporting outcomes concerning patients with neurologic or mechanic, specific or aspecific low back pain with or without radiculopathy were included. LBP was considered chronic if pain had lasted more than 6 weeks. Data from 47 articles (9007 patients: mean age: 52.62 ± 7.0 years; mean BMI: 28.26 ± 2.8; mean follow-up: 3.23 ± 3.2 months) were obtained.

EXPERT OPINION

According to published level I evidence, only baclofen, duloxetine, NSAIDs, and opiates showed to improve pain and disability levels in patients with LBP. However, the patients' demographics are heterogeneous, and the results must be interpreted with caution and in the light of possible adverse events connected to the use of these drugs.

AAPT Diagnostic Criteria for Chronic Low Back Pain

Chronic low back pain (CLBP) conditions are highly prevalent and constitute the leading cause of disability worldwide. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks (ACTTION) public-private partnership with the US Food and Drug Administration and the American Pain Society (APS), have combined to create the ACTTION-APS Pain Taxonomy (AAPT). The AAPT initiative convened a working group to develop diagnostic criteria for CLBP. The working group identified 3 distinct low back pain conditions which result in a vast public health burden across the lifespan. This article focuses on: 1) the axial predominant syndrome of chronic musculoskeletal low back pain, 2) the lateralized, distally-radiating syndrome of chronic lumbosacral radicular pain 3) and neurogenic claudication associated with lumbar spinal stenosis. This classification of CLBP is organized according to the AAPT multidimensional framework, specifically 1) core diagnostic criteria; 2) common features; 3) common medical and psychiatric comorbidities; 4) neurobiological, psychosocial, and functional consequences; and 5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors. PERSPECTIVE: An evidence-based classification of CLBP conditions was constructed for the AAPT initiative. This multidimensional diagnostic framework includes: 1) core diagnostic criteria; 2) common features; 3) medical and psychiatric comorbidities; 4) neurobiological, psychosocial, and functional consequences; and 5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors.

Anticonvulsants in the treatment of low back pain and lumbar radicular pain: a systematic review and meta-analysis

BACKGROUND

The use of anticonvulsants (e.g., gabapentin, pregabalin) to treat low back pain has increased substantially in recent years despite limited supporting evidence. We aimed to determine the efficacy and tolerability of anticonvulsants in the treatment of low back pain and lumbar radicular pain compared with placebo.

METHODS

A search was conducted in 5 databases for studies comparing an anticonvulsant to placebo in patients with nonspecific low back pain, sciatica or neurogenic claudication of any duration. The outcomes were self-reported pain, disability and adverse events. Risk of bias was assessed using the Physiotherapy Evidence Database (PEDro) scale, and quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Data were pooled and treatment effects were quantified using mean differences for continuous and risk ratios for dichotomous outcomes.

RESULTS

Nine trials compared topiramate, gabapentin or pregabalin to placebo in 859 unique participants. Fourteen of 15 comparisons found anticonvulsants were not effective to reduce pain or disability in low back pain or lumbar radicular pain; for example, there was high-quality evidence of no effect of gabapentinoids versus placebo on chronic low back pain in the short term (pooled mean difference [MD] -0.0, 95% confidence interval [CI] -0.8 to 0.7) or for lumbar radicular pain in the immediate term (pooled MD -0.1, 95% CI -0.7 to 0.5). The lack of efficacy is accompanied by increased risk of adverse events from use of gabapentinoids, for which the level of evidence is high.

INTERPRETATION

There is moderate- to high-quality evidence that anticonvulsants are ineffective for treatment of low back pain or lumbar radicular pain. There is high-quality evidence that gabapentinoids have a higher risk for adverse events.

PROTOCOL REGISTRATION

PROSPERO-CRD42016046363.

Incorporating baseline measurements into the analysis of crossover trials with time-to-event endpoints

Two-period two-treatment (2×2) crossover designs are commonly used in clinical trials. For continuous endpoints, it has been shown that baseline (pretreatment) measurements collected before the start of each treatment period can be useful in improving the power of the analysis. Methods to achieve a corresponding gain for censored time-to-event endpoints have not been adequately studied. We propose a method in which censored values are treated as missing data and multiply imputed using prespecified parametric event time models. The event times in each imputed data set are then log-transformed and analyzed using a linear model suitable for a 2×2 crossover design with continuous endpoints, with the difference in period-specific baselines included as a covariate. Results obtained from the imputed data sets are synthesized for point and confidence interval estimation of the treatment ratio of geometric mean event times using model averaging in conjunction with Rubin's combination rule. We use simulations to illustrate the favorable operating characteristics of our method relative to two other methods for crossover trials with censored time-to-event data, ie, a hierarchical rank test that ignores the baselines and a stratified Cox model that uses each study subject as a stratum and includes period-specific baselines as a covariate. Application to a real data example is provided.

Why are there no drugs indicated for sciatica, the most common chronic neuropathic syndrome of all?

This review examines the stark contrast between the successes and failures of the clinical development of analgesics for different types of chronic low back pain (CLBP) syndrome over the past three decades. Multiple drugs with differing mechanisms of action have been developed for nonspecific axial-predominant low back syndromes and yet not a single therapy is indicated for any neuropathic low back pain syndrome (e.g., sciatica). Clinician findings have informed the entry criteria for neuropathic low back pain clinical trials, whereas entry criteria of axial CLBP trials have prioritized only patient reports of pain. This key difference could account for the lack of success in developing therapies for neuropathic low back pain in an era marked by successful development of analgesics for other types of CLBP as well as many chronic pain syndromes associated with nerve injury, such as post-herpetic neuralgia (PHN).

Pharmacotherapy for chronic non-specific low back pain: current and future options

INTRODUCTION

Low back pain is associated with a large burden-of-illness. It is responsible for the most years lived with disability as compared with any other medical condition. A comprehensive overview of the evidence on pharmacological treatment options for chronic low back pain is lacking. This review evaluates the evidence for the benefits and risks of currently available pharmacological treatments for chronic low back pain.

AREAS COVERED

The authors focus on the recent (Cochrane) systematic reviews and meta-analyses of randomized clinical trials covering paracetamol (acetaminophen), NSAIDs, muscle relaxants, antidepressants, anticonvulsants, opioids, and other (new) drugs.

EXPERT OPINION

The overall impression of the efficacy of pharmacological treatments for patients with chronic low back pain is rather sobering. The effects on pain reduction and improvement of function are commonly small to moderate and short lasting when compared to placebo. At the same time, the various types of drugs are not without side-effects. This holds especially true for serious side-effects associated with (prolonged) use of strong opioids. Future studies on patients with chronic back pain should aim to identify subgroups of patients with good response to specific pharmacological treatment to facilitate personalized care.

Limaprost or Pregabalin: Preoperative and Postoperative Medication for Pain due to Lumbar Spinal Stenosis

PURPOSE

We aimed to evaluate the incidence of (and risk factors for) postoperative pregabalin and/or limaprost to treat persistent numbness and/or pain of the lower extremities after lumbar spinal stenosis (LSS) surgery.

METHODS

Medical records of 329 patients (168 men, 161 women; average age 70 years) were retrospectively reviewed for data on the duration of LSS diagnosis; LSS disease; preoperative medication (limaprost, pregabalin, or combined limaprost/pregabalin; duration); symptoms; preoperative/postoperative intermittent claudication (IC); operation type; and postoperative medication and period.

RESULTS

Limaprost, pregabalin, and combined limaprost/pregabalin were prescribed preoperatively for 43%, 7%, and 5% of patients, respectively. At an average of 21 months postoperatively, limaprost, pregabalin, and combined therapy were prescribed in 11%, 8%, 4% of patients, respectively. Medication requirement was significantly lower postoperatively than preoperatively (P < 0.0001). Significant risk factors for required postoperative medication were required preoperative medication (odds ratio [OR] 3.088, 95% confidence interval [CI] 1.679 to 5.681]; postoperative period (OR 1.063, 95% CI 1.031 to 1.096); and postoperative IC (OR 3.868, 95% CI 1.481 to 10.103). A negative impact from postoperative medication was seen in patients who had undergone decompression surgery (OR 0.589, 95% CI 0.377 to 0.918).

CONCLUSIONS

Overall, 23% of LSS patients required medication for pain and/or numbness at 21 months postoperatively. Significant factors portending required postoperative medication were preoperative medication, longer postoperative period, and postoperative IC. A negative influence from postoperative medication was seen in patients who had undergone decompression surgery without fusion.

Benefits and safety of gabapentinoids in chronic low back pain: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Chronic Low Back Pain (CLBP) is very common, with a lifetime prevalence between 51% and 80%. In majority, it is nonspecific in nature and multifactorial in etiology. Pregabalin (PG) and Gabapentin (GB) are gabapentinoids that have demonstrated benefit in neuropathic pain conditions. Despite no clear rationale, they are increasingly used for nonspecific CLBP. They necessitate prolonged use and are associated with adverse effects and increased cost. Recent guidelines from the National Health Service (NHS), England, expressed concerns on their off-label use, in addition to the risk of misuse. We aimed to assess the effectiveness and safety of gabapentinoids in adult CLBP patients.

METHODS

Electronic databases of MEDLINE, EMBASE, and Cochrane were searched from their inception until December 20th, 2016. We included randomized control trials reporting the use of gabapentinoids for the treatment of CLBP of >3 months duration, in adult patients. Study selection and data extraction was performed independently by paired reviewers. Outcomes were guided by Initiative on Methods, Measurement and Pain Assessment in Clinical Trials guidelines, with pain relief and safety as the primary outcomes. Meta-analyses were performed for outcomes reported in 3 or more studies. Outcomes were reported as mean differences (MDs) or risk ratios (RRs) with their corresponding 95% confidence intervals (CIs), and I2 in percentage representing the percentage variability in effect estimates that could be explained by heterogeneity. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) was used to assess the quality of evidence.

RESULTS

Out of 1,385 citations, eight studies were included. Based on the interventions and comparators, studies were analyzed in 3 different groups. GB compared with placebo (3 studies, n = 185) showed minimal improvement of pain (MD = 0.22 units, 95% CI [-0.5 to 0.07] I2 = 0%; GRADE: very low). Three studies compared PG with other types of analgesic medication (n = 332) and showed greater improvement in the other analgesic group (MD = 0.42 units, 95% CI [0.20 to 0.64] I2 = 0; GRADE: very low). Studies using PG as an adjuvant (n = 423) were not pooled due to heterogeneity, but the largest of them showed no benefit of adding PG to tapentadol. There were no deaths or hospitalizations reported. Compared with placebo, the following adverse events were more commonly reported with GB: dizziness-(RR = 1.99, 95% CI [1.17 to 3.37], I2 = 49); fatigue (RR = 1.85, 95% CI [1.12 to 3.05], I2 = 0); difficulties with mentation (RR = 3.34, 95% CI [1.54 to 7.25], I2 = 0); and visual disturbances (RR = 5.72, 95% CI [1.94 to 16.91], I2 = 0). The number needed to harm with 95% CI for dizziness, fatigue, difficulties with mentation, and visual disturbances were 7 (4 to 30), 8 (4 to 44), 6 (4 to 15), and 6 (4 to 13) respectively. The GRADE evidence quality was noted to be very low for dizziness and fatigue, low for difficulties with mentation, and moderate for visual disturbances. Functional and emotional improvements were reported by few studies and showed no significant improvements.

CONCLUSIONS AND RELEVANCE

Existing evidence on the use of gabapentinoids in CLBP is limited and demonstrates significant risk of adverse effects without any demonstrated benefit. Given the lack of efficacy, risks, and costs associated, the use of gabapentinoids for CLBP merits caution. There is need for large high-quality trials to more definitively inform this issue.

TRIAL REGISTRATION

PROSPERO CRD42016034040.

Pregabalin for Refractory Radicular Leg Pain due to Lumbar Spinal Stenosis: A Preliminary Prospective Study

We investigated the efficacy of pregabalin (PGB) for neuropathic leg pain in lumbar spinal stenosis (LSS) patients with disturbed activities of daily living (ADL)/quality of life (QOL) in a prospective observational study. Subjects were a total of 104 LSS patients with neuropathic pain (NeP) in leg and neurological intermittent claudication (IMC) refractory to nonsteroidal anti-inflammatory drugs (NSAIDs) for at least a month. NeP was identified using screening tool, Pain DETECT questionnaire. Visual analog scale (VAS) scores and responses to the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) were assessed before and 6 weeks after PGB treatment initiation. Changes in IMC distance and adverse events were also recorded. PGB significantly improved their VAS scores for pain and sleep quality (P < 0.001). With respect to JOABPEQ, significant improvements were observed with regard to the following dimensions: pain-related disorders (P < 0.01), lumbar spine dysfunction (P = 0.031), gait disturbance (P = 0.028), and psychological disorders (P = 0.014). The IMC distance showed an improvement tendency after PGB treatment, albeit with no significance (P = 0.063). Minor adverse events such as dizziness were observed. PGB can be effective for neuropathic leg pain refractory to NSAIDs in LSS patients, resulting in not only pain control but also improving lower back pain-related ADL/QOL scores.

Evaluation of outcome measures for neurogenic claudication: A patient-centered approach

OBJECTIVES

To determine whether patients with neurogenic claudication associated with lumbar spinal stenosis would prefer a treatment that makes it possible for them to walk farther or walk with less pain; to examine associations between this treatment preference and patient-reported and in-clinic treadmill testing measures of walking ability and walking-associated pain.

METHODS

In this cross-sectional study, 269 patients with neurogenic claudication were asked to report their pain intensity when walking, complete the Swiss Spinal Stenosis Questionnaire, rank their outcome preferences for treatment, and undergo standardized treadmill testing, including measures of final pain rating and time to first pain of moderate intensity (Tfirst). Descriptive statistics were used to characterize patient preferences for treatment outcome. Associations between self-report questionnaires and standardized treadmill testing outcomes were evaluated using Spearman correlations.

RESULTS

Seventy-nine percent of patients expressed a preference for treatment that allowed them to walk with less pain. Preference for reduced pain was associated with higher pain during daily walking, along with a shorter Tfirst and higher final pain severity on treadmill testing. In contrast, patient preference for treatment outcome was not associated with self-reported measures of daily walking capacity or walking distance on the treadmill.

CONCLUSIONS

A majority of patients with neurogenic claudication prioritized walking with reduced pain over walking farther. Reduction in pain while walking may therefore constitute a sufficient patient-focused treatment outcome for the majority of these patients. These results have implications for clinical trial design and assessment of treatment efficacy in neurogenic claudication.

Effectiveness of pregabalin for the treatment of chronic low back pain with accompanying lower limb pain (neuropathic component): a non-interventional study in Japan

Objective

To evaluate the impact of pregabalin on sleep, pain, function, and health status in patients with chronic low back pain with accompanying neuropathic pain (CLBP-NeP) under routine clinical practice.

Methods

This prospective, non-interventional, observational study enrolled Japanese adults (≥18 years) with CLBP-NeP of duration ≥3 months and severity ≥5 on a numerical rating scale (0= no pain, 10= worst possible pain). Treatment was 8 weeks with pregabalin (n=157) or usual care alone (n=174); choice of treatment was determined by the physician. The primary efficacy outcome was change from baseline to 8 weeks in pain-related interference with sleep, assessed using the Pain-Related Sleep Interference Scale (PRSIS; 0= did not interfere with sleep, 10= completely interferes with sleep). Secondary endpoints were changes in PRSIS at week 4, and changes at weeks 4 and 8 in pain (numerical rating scale), function (Roland-Morris Disability Questionnaire), and quality of life (EuroQol 5D-5L); global assessments of change were evaluated from the clinician and patient perspectives at the final visit.

Results

Demographic characteristics were similar between cohorts, but clinical characteristics suggested greater disease severity in the pregabalin group including a higher mean (standard deviation) pain score, 6.3 (1.2) versus 5.8 (1.1) (P<0.001). For the primary endpoint, pregabalin resulted in significantly greater improvements in PRSIS at week 8, least-squares mean changes of −1.3 versus −0.4 for usual care (P<0.001); pregabalin also resulted in greater PRSIS improvement at week 4 (P=0.012). Relative to usual care at week 8, pregabalin improved pain and function (both P<0.001), and showed global improvements since beginning study medication (P<0.001). Pregabalin was well tolerated.

Conclusion

In clinical practice in patients with CLBP-NeP, pregabalin showed significantly greater improvements in pain-related interference with sleep relative to usual care. In addition, pregabalin significantly improved pain, function, and health status, suggesting the benefits of pregabalin for overall health and well-being relative to usual care in these patients. (Clinicaltrials. gov identifier NCT02273908).