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1.  Identifying neuropathic pain in patients with head and neck cancer: use of the Leeds Assessment of Neuropathic Symptoms and Signs Scale 
The Leeds Assessment of Neuropathic Symptoms and Signs Scale (LANSS) is a simple bedside test in two parts—a patient-completed questionnaire and a brief clinical assessment. Its diagnostic capabilities have never been tested in patients with cancer pain. To determine these we conducted a prospective study in outpatients with head and neck cancer. All patients with pain completed the LANSS and underwent a medical assessment with a palliative care physician, whose findings were then reviewed by a pain specialist blinded to the LANSS scores. We assessed acceptability and understanding of the LANSS by patients and calculated the sensitivity and specificity of total LANSS scores and subscores derived from the patient-completed section.
Of 130 patients approached, 125 took part. 25 (20%) of these had cancer related pain, mean score on an 11 point numerical rating scale 6.3 (median 6.0, range 3-10). Average age was 60 years (median 60, range 27-84); 56% were male. LANSS completion time was about five minutes, and the procedure was acceptable to all patients. The pain specialist diagnosed neuropathic pain in 14/25 patients, in 13 of whom the neuropathic pain was part of a mixed pain picture. The LANSS correctly identified 11 of these cases (sensitivity 79%; specificity 100%). The patient-completed section alone had a sensitivity of 86% and a specificity of 91%.
The LANSS is a simple and suitable screening test for neuropathic pain in patients with head and neck cancer related pain, although some modifications might improve it.
PMCID: PMC539565  PMID: 12893852
2.  Relationship between electrodiagnostic severity and neuropathic pain assessed by the LANSS pain scale in carpal tunnel syndrome 
The aim of the study was to investigate the relationship between the presence of neuropathic pain assessed by the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scale and electrophysiological findings in patients with carpal tunnel syndrome (CTS).
We studied 124 hands with idiopathic CTS with pain complaints involving hand and wrist. All hands were assessed by the LANSS with which a score of 12 or more is defined as pain dominated by neuropathic mechanisms. These hands were assigned to minimal, mild, moderate, severe, or extreme severe groups according to the results of the median nerve conduction studies.
A LANSS score ≥ 12, suggestive of pain dominated by neuropathic mechanisms, was defined in 59 (47.6%) CTS hands. Pain intensity was significantly higher in CTS hands with a LANSS score ≥ 12 (P < 0.001). Among electrophysiological findings, compound muscle action potential amplitude was significantly lower in hands with a LANSS score ≥ 12 compared with hands with a LANSS score < 12 (P = 0.020). Severity of CTS was not significantly different between LANSS ≥ 12 and LANSS < 12 groups. Electrophysiological severity was significantly higher in CTS hands with evoked pain (P = 0.005) and allodynia (P < 0.001) in LANSS subscore analysis.
We suggest that the presence of pain dominated by neuropathic mechanisms in CTS is not related to electrophysiological CTS severity. Neuropathic pain should be assessed carefully in patients with CTS, and an appropriate treatment plan should be chosen, taking into account the clinical and electrophysiological findings together with the true pain classification.
PMCID: PMC3544346  PMID: 23326196
electrodiagnostic evaluation; carpal tunnel syndrome; LANSS; neuropathic pain
3.  Neuropathic pain in the community: More under-treated than refractory? 
Pain  2013;154(5):690-699.
There is a significant proportion of chronic pain that is persistent and neuropathic, appears undertreated or untreated, and is associated with poor health and quality of life.
Best current estimates of neuropathic pain prevalence come from studies using screening tools detecting pain with probable neuropathic features; the proportion experiencing significant, long-term neuropathic pain, and the proportion not responding to standard treatment are unknown. These “refractory” cases are the most clinically important to detect, being the most severe, requiring specialist treatment. The aim of this study was to estimate the proportion of neuropathic pain in the population that is “refractory,” and to quantify associated clinical and demographic features. We posted self-administered questionnaires to 10,000 adult patients randomly selected from 10 general practitioner practices in 5 UK locations. The questionnaire contained chronic pain identification and severity questions, cause of pain, SF-12, EQ-5D, S-LANSS (Self-administered Leeds Assessment of Neuropathic Signs and Symptoms), PSEQ (Pain Self-Efficacy Questionnaire), use of neuropathic pain medications, and health care utilisation. These data were combined to determine the presence and characteristics of “refractory” neuropathic pain according to the defining features identified by a Delphi survey of international experts. Graded categories of chronic pain with and without neuropathic characteristics were generated, incorporating the refractory criteria. Completed questionnaires were returned by 4451 individuals (response rate 47%); 399 had “chronic pain with neuropathic characteristics” (S-LANSS positive, 8.9% of the study sample); 215 (53.9%) also reported a positive relevant history (“Possible neuropathic pain”); and 98 (4.5% of all Chronic Pain) also reported an “adequate” trial of at least one neuropathic pain drug (“Treated possible neuropathic pain”). The most refractory cases were associated with dramatically poorer physical and mental health, lower pain self-efficacy, higher pain intensity and pain-related disability, and greater health care service use.
PMCID: PMC3630326  PMID: 23485369
Neuropathic pain; Chronic pain; Epidemiology; S-LANSS; Refractory
4.  Pregabalin, celecoxib, and their combination for treatment of chronic low-back pain 
The efficacy and safety of the association of celecoxib [a selective cyclooxygenase-2 (COX-2) inhibitor] and pregabalin (commonly used to control neuropathic pain), compared with monotherapy of each, were evaluated for the treatment of chronic low-back pain, a condition known to be due to neuropathic as well as nociceptive pain mechanisms.
Materials and methods
In this prospective randomized trial, 36 patients received three consecutive 4-week treatment regimes, randomly assigned: celecoxib plus placebo, pregabalin plus placebo, and celecoxib plus pregabalin. All patients were assessed by using a visual analogue scale (VAS, 0–100 mm) and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain scale by an investigator blinded to the administered pharmacological treatment.
Celecoxib and pregabalin were effective in reducing low-back pain when patients were pooled according to LANSS score. The association of celecoxib and pregabalin was more effective than either monotherapy in a mixed population of patients with chronic low-back pain and when data were pooled according to LANSS score. Adverse effects of drug association and monotherapies were similar, with reduced drug consumption in the combined therapy.
Combination of celecoxib and pregabalin is more effective than monotherapy for chronic low-back pain, with similar adverse effects.
PMCID: PMC2784066  PMID: 19921480
Pregabalin; Celecoxib; Low-back pain; Polypharmacotherapy
5.  Pregabalin, celecoxib, and their combination for treatment of chronic low-back pain 
The efficacy and safety of the association of celecoxib [a selective cyclooxygenase-2 (COX-2) inhibitor] and pregabalin (commonly used to control neuropathic pain), compared with monotherapy of each, were evaluated for the treatment of chronic low-back pain, a condition known to be due to neuropathic as well as nociceptive pain mechanisms.
Materials and methods
In this prospective randomized trial, 36 patients received three consecutive 4-week treatment regimes, randomly assigned: celecoxib plus placebo, pregabalin plus placebo, and celecoxib plus pregabalin. All patients were assessed by using a visual analogue scale (VAS, 0–100 mm) and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain scale by an investigator blinded to the administered pharmacological treatment.
Celecoxib and pregabalin were effective in reducing low-back pain when patients were pooled according to LANSS score. The association of celecoxib and pregabalin was more effective than either monotherapy in a mixed population of patients with chronic low-back pain and when data were pooled according to LANSS score. Adverse effects of drug association and monotherapies were similar, with reduced drug consumption in the combined therapy.
Combination of celecoxib and pregabalin is more effective than monotherapy for chronic low-back pain, with similar adverse effects.
PMCID: PMC2784066  PMID: 19921480
Pregabalin; Celecoxib; Low-back pain; Polypharmacotherapy
6.  Economic and humanistic burden of post-trauma and post-surgical neuropathic pain among adults in the United States 
Journal of Pain Research  2013;6:459-469.
Neuropathic pain (NeP) can be chronic, debilitating, and can interfere with sleep, functioning, and emotional well being. While there are multiple causes of NeP, few studies have examined the disease burden and treatment patterns associated with post-traumatic/post-surgical (PTPS) NeP.
To characterize pain, health status, function, health care resource utilization, lost productivity, and costs among subjects with PTPS NeP in the United States.
This observational study enrolled 100 PTPS NeP subjects recruited during routine visits from general practitioner and specialist sites. Subjects completed a one-time questionnaire with validated measures of pain severity and pain interference, health status, sleep, anxiety and depression, productivity, and study-specific items on demographics, employment status, and out-of-pocket expenses. Investigators completed a case report form based on a 6-month retrospective chart review, recording subjects’ clinical characteristics as well as current and previous medications/treatments for NeP. Subjects were stratified into mild, moderate, and severe pain groups.
Subjects’ demographic characteristics were: mean age of 54.9 years, 53% female, and 22% employed for pay. Mean pain severity score was 5.6 (0–10 scale), with 48% and 35% classified as having moderate and severe pain, respectively. The mean number of comorbidities increased with greater pain severity (P = 0.0009). Patient-reported outcomes were worse among PTPS NeP subjects with more severe pain, including pain interference with function, health state utility, sleep, and depression (P < 0.0001). Eighty-two percent of subjects were prescribed two or more NeP medications. The total mean annualized adjusted direct and indirect costs per subject were $11,846 and $29,617, respectively. Across pain severity levels, differences in annualized adjusted direct and indirect costs were significant (P < 0.0001).
PTPS NeP subjects reported high pain scores, which were associated with poor health utility, sleep, mood, and function, as well as high health care resource utilization and costs. The quality of life impact and costs attributable to PTPS NeP suggest an unmet need for effective and comprehensive management.
PMCID: PMC3698142  PMID: 23825931
trauma/surgery; neuropathic pain; quality-of-life; patient-reported outcomes; costs; productivity
7.  Longlasting antalgic effects of daily sessions of repetitive transcranial magnetic stimulation in central and peripheral neuropathic pain 
Background and objective: A single session of repetitive transcranial magnetic stimulation (rTMS) over motor cortex had been reported to produce short term relief of some types of chronic pain. The present study investigated whether five consecutive days of rTMS would lead to longer lasting pain relief in unilateral chronic intractable neuropathic pain.
Patients and methods: Forty eight patients with therapy resistant chronic unilateral pain syndromes (24 each with trigeminal neuralgia (TGN) and post-stroke pain syndrome (PSP)) participated. Fourteen from each group received 10 minutes real rTMS over the hand area of motor cortex (20 Hz, 10x10 s trains, intensity 80% of motor threshold) every day for five consecutive days. The remaining patients received sham stimulation. Pain was assessed using a visual analogue scale (VAS) and the Leeds assessment of neuropathic symptoms and signs (LANSS) scale, before, after the first, fourth, and fifth sessions, and two weeks after the last session.
Results: No significant differences were found in basal pain ratings between patients receiving real- and sham-rTMS. However, a two factor ANOVA revealed a significant "± TMS" x "time" interaction indicating that real and sham rTMS had different effects on the VAS and LANSS scales. Post hoc testing showed that in both groups of patients, real-rTMS led to a greater improvement in scales than sham-rTMS, evident even two weeks after the end of the treatment. No patient experienced adverse effects.
Conclusion: These results confirm that five daily sessions of rTMS over motor cortex can produce longlasting pain relief in patients with TGN or PSP.
PMCID: PMC1739662  PMID: 15897507
8.  An open-label, non-randomized comparison of venlafaxine and gabapentin as monotherapy or adjuvant therapy in the management of neuropathic pain in patients with peripheral neuropathy 
Journal of pain research  2010;3:33-49.
Although many therapies are used in the management of neuropathic pain (NeP) due to polyneuropathy (PN), few comparison studies exist. We performed a prospective, non-randomized, unblended, efficacy comparison of the serotonin-norepinephrine reuptake inhibitor venlafaxine, as either monotherapy or adjuvant therapy, with a first-line medication for NeP, gabapentin, in patients with PN-related NeP. VAS pain scores were assessed after 3 and 6 months in intervention groups and in a cohort of patients receiving no pharmacotherapy. In a total of 223 patients, we analyzed pain quantity and quality (visual analogue scale [VAS] score, Brief Pain Inventory [BPI]), quality of life and health status measures [EuroQol 5 Domains, EQ-5D], Medical Outcomes Sleep Study Scale [MOSSS], Hospital Anxiety and Depression Scale [HADS] and Short Form 36 Health Survey [SF-36]) after 6 months of therapy. Significant improvements in VAS pain scores occurred for all treatment groups after 6 months. Improvements in aspects of daily life and anxiety were identified in all treatment groups. Our data suggest that monotherapy or adjuvant therapy with venlafaxine is comparable to gabapentin for NeP management. We advocate for head-to-head, randomized, double-blinded studies of current NeP therapies.
PMCID: PMC3004650  PMID: 21197308
peripheral neuropathy; neuropathic pain; pharmacotherapy; venlafaxine; gabapentin
9.  Pharmacological management of chronic neuropathic pain: Revised consensus statement from the Canadian Pain Society 
Neuropathic pain is defined as a lesion or disease of the somatosensory system, and may involve the central or peripheral nervous systems. Treatment of neuropathic pain is a challenge for clinicians involved in affected patients' care. In 2007, the first guidelines for the treatment of neuropathic pain in the Canadian context were produced by the Canadian Pain Society. This update to these guidelines incorporates new evidence published since the first guidelines were released.
Neuropathic pain (NeP), redefined as pain caused by a lesion or a disease of the somatosensory system, is a disabling condition that affects approximately two million Canadians.
To review the randomized controlled trials (RCTs) and systematic reviews related to the pharmacological management of NeP to develop a revised evidence-based consensus statement on its management.
RCTs, systematic reviews and existing guidelines on the pharmacological management of NeP were evaluated at a consensus meeting in May 2012 and updated until September 2013. Medications were recommended in the consensus statement if their analgesic efficacy was supported by at least one methodologically sound RCT (class I or class II) showing significant benefit relative to placebo or another relevant control group. Recommendations for treatment were based on the degree of evidence of analgesic efficacy, safety and ease of use.
Analgesic agents recommended for first-line treatments are gabapentinoids (gabapentin and pregabalin), tricyclic antidepressants and serotonin noradrenaline reuptake inhibitors. Tramadol and controlled-release opioid analgesics are recommended as second-line treatments for moderate to severe pain. Cannabinoids are now recommended as third-line treatments. Recommended fourth-line treatments include methadone, anticonvulsants with lesser evidence of efficacy (eg, lamotrigine, lacos-amide), tapentadol and botulinum toxin. There is support for some analgesic combinations in selected NeP conditions.
These guidelines provide an updated, stepwise approach to the pharmacological management of NeP. Treatment should be individualized for each patient based on efficacy, side-effect profile and drug accessibility, including cost. Additional studies are required to examine head-to-head comparisons among analgesics, combinations of analgesics, long-term outcomes and treatment of pediatric, geriatric and central NeP.
PMCID: PMC4273712  PMID: 25479151
Analgesic agents; Neuropathic pain; Randomized controlled trials
10.  The impact of neuropathic pain and other comorbidities on the quality of life in patients with diabetes 
Diabetic polyneuropathy (DPN) is one of the most common complications of diabetes and can exist with or without neuropathic pain. We were interested in how neuropathic pain impairs the quality of life in diabetic patients and what is the role of comorbidities in this condition.
The study included 80 patients with painful DPN (group “P”) and 80 patients with DPN, but without neuropathic pain (group “D”). Visual analogue scale (VAS) and Leeds assessment of neuropathic symptoms and signs (LANSS) pain scale were used for assessment of neuropathic pain, SF-36 standardized questionnaire for assessment of the quality of life and BDI questionnaire for assessment of depression.
Subjects in group P had statistically significantly lower values compared to group D in all 8 dimensions and both summary values of the SF-36 scale. We ascribe the extremely low results of all parameters of SF-36 scale in group P to painful diabetic polyneuropathy with its complications. The patients in group D showed higher average values in all dimension compared to group P, but also somewhat higher quality of life compared to general population of Croatia in 4 of 8 dimensions, namely vitality (VT), social functioning (SF), role-emotional (RE) and mental health (MH), which was unexpected result.
Clinically, the most pronounced differences between two groups were noted in sleeping disorders and problems regarding micturition and defecation , which were significantly more expressed in group P. The similar situation was with walking distance and color-doppler sonography of carotid arteries, which were significantly worse in group P. Consequently, subjects in group P were more medicated than the patients in group D, particularly with tramadol, antiepileptics and antidepressants.
Painful DPN is a major factor that influences various aspects of quality of life in diabetic patients. Additionally, this study gives an overview of diabetic population in the Republic of Croatia, information that could prove useful in future studies.
PMCID: PMC4264315  PMID: 25468384
Diabetes; Diabetic polyneuropathy; Quality of life; Comorbidities
11.  Measurement properties of painDETECT by average pain severity 
Since the burden of neuropathic pain (NeP) increases with pain severity, it is important to characterize and quantify pain severity when identifying NeP patients. This study evaluated whether painDETECT, a screening questionnaire to identify patients with NeP, can distinguish pain severity.
Materials and methods
Subjects (n=614, 55.4% male, 71.8% white, mean age 55.5 years) with confirmed NeP were identified during office visits to US community-based physicians. The Brief Pain Inventory – Short Form stratified subjects by mild (score 0–3, n=110), moderate (score 4–6, n=297), and severe (score 7–10, n=207) average pain. Scores on the nine-item painDETECT (seven pain-symptom items, one pain-course item, one pain-irradiation item) range from −1 to 38 (worst NeP); the seven-item painDETECT scores (only pain symptoms) range from 0 to 35. The ability of painDETECT to discriminate average pain-severity levels, based on the average pain item from the Brief Pain Inventory – Short Form (0–10 scale), was evaluated using analysis of variance or covariance models to obtain unadjusted and adjusted (age, sex, race, ethnicity, time since NeP diagnosis, number of comorbidities) mean painDETECT scores. Cumulative distribution functions on painDETECT scores by average pain severity were compared (Kolmogorov–Smirnov test). Cronbach’s alpha assessed internal consistency reliability.
Unadjusted mean scores were 15.2 for mild, 19.8 for moderate, and 24.0 for severe pain for the nine items, and 14.3, 18.6, and 22.7, respectively, for the seven items. Adjusted nine-item mean scores for mild, moderate, and severe pain were 17.3, 21.3, and 25.3, respectively; adjusted seven-item mean scores were 16.4, 20.1, and 24.0, respectively. All pair-wise comparisons of scores between pain-severity groups showed sizable and statistically significant differences (P<0.0001). Cumulative distribution functions showed distinct separation between severity (P<0.0001). Cronbach’s alphas were 0.76 and 0.80 for the nine- and seven-item scales, respectively.
This study provides strong psychometric evidence on the validity and reliability of painDETECT for distinguishing average pain severity in patients with NeP.
PMCID: PMC4226388  PMID: 25395867
neuropathic pain; painDETECT; pain severity; psychometric properties
12.  Pain severity and the economic burden of neuropathic pain in the United States: BEAT Neuropathic Pain Observational Study 
As with many chronic conditions, patients with neuropathic pain (NeP) are high consumers of health care resources. However, limited literature exists on the economic burden of NeP, including its impact on productivity. The aim of this study was to characterize health care resource utilization, productivity, and costs associated with NeP by pain severity level in US adults.
Subjects (n=624) with painful diabetic peripheral neuropathy, human immunodeficiency virus-related peripheral NeP, post-trauma/post-surgical NeP, spinal cord injury with NeP, chronic low back pain with NeP, and small fiber neuropathy were recruited during routine office visits to US community-based general practitioners and specialists. Clinicians captured clinical characteristics, NeP-related medications, and health care resource utilization based on 6-month retrospective medical chart review. Subjects completed questionnaires on demographics, pain/symptoms, costs, and productivity. Brief Pain Inventory pain severity scores were used to classify subjects by mild, moderate, or severe pain. Annualized NeP-related costs (adjusted for covariates) were estimated, and differences across pain severity groups were evaluated.
In total, 624 subjects were recruited (mean age 55.5±13.7 years; 55.4% male), and 504/624 (80.8%) reported moderate or severe pain. Statistically significant differences were observed across pain severity levels for number of comorbidities, prescription medications, physician office visits, and lost productivity (all P≤0.0001). At all pain severity levels, indirect costs were the primary cost driver. After adjusting for demographic and clinical variables, total mean (95% confidence interval [CI]) annualized direct medical costs to payers, direct costs to subjects, and indirect costs per subject were US$6,016 (95% CI 5,316–6,716), US$2,219 (95% CI 1,919–2,519), and US$19,000 (95% CI 17,197–20,802), respectively, with significant differences across pain severity levels.
Subjects with NeP, mainly those showing moderate or severe pain, had significant associations between pain severity and NeP-related health care resource utilization, productivity, and costs. The economic burden, particularly indirect costs, was highest among those with severe pain and higher than previously reported in studies of specific NeP conditions.
PMCID: PMC4218900  PMID: 25378940
burden of illness; neuropathic pain management; health care costs; health care resource use; productivity
13.  Pain After Spinal Cord Injury: An Evidence-based Review for Clinical Practice and Research 
To examine the reliability, validity, sensitivity, and practicality of various outcome measures for pain after spinal cord injury (SCI), and to provide recommendations for specific measures for use in clinical trials.
Data Sources:
Relevant articles were obtained through a search of MEDLINE, EMBASE, CINAHL, and PubMed databases from inception through 2006.
Study Selection:
The authors performed literature searches to find articles containing data relevant to the reliability and validity of each pain outcome measure in SCI and selected non-SCI populations.
Data Extraction:
After reviewing the articles, an investigator extracted information utilizing a standard template. A second investigator reviewed the chosen articles and the extracted pertinent information to confirm the findings of the first investigator.
Data Synthesis:
Taking into consideration both the quantity and quality of the studies analyzed, judgments on reliability and validity of the measures were made by the two investigators. Based upon these judgments, recommendations were formulated for use of specific measures in future clinical trials. In addition, for a subset of measures a voting process by a larger group of SCI experts allowed formulation of recommendations including determining which measures should be incorporated into a minimal dataset of measures for clinical trials and which ones need revision and further validity and reliability testing before use.
A 0–10 Point Numerical Rating Scale (NRS) is recommended as the outcome measure for pain intensity after SCI, while the 7-Point Guy/Farrar Patient Global Impression of Change (PGIC) scale is recommended as the outcome measure for global improvement in pain. The SF-36 single pain interference question and the Multidimensional Pain Inventory (MPI) or Brief Pain Inventory (BPI) pain interference items are recommended as the outcome measures for pain interference after SCI. Brush or cotton wool and at least one high-threshold von Frey filament are recommended to test mechanical allodynia/hyperalgesia while a Peltier-type thermotester is recommended to test thermal allodynia/hyperalgesia. The International Association for the Study of Pain (IASP) or Bryce-Ragnarsson pain taxonomies are recommended for classification of pain after SCI, while the Neuropathic Pain Scale (NPS) is recommended for measuring change in neuropathic pain and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) for quantitating neuropathic and nociceptive pain discrimination.
PMCID: PMC2141724  PMID: 18092558
Pain, chronic, classification, neuropathic, non-neuropathic; Treatment outcome; Spinal cord injuries; Pain scales; Reproducibility of results
14.  The impact of enrollment in a specialized interdisciplinary neuropathic pain clinic 
Chronic pain clinics have been created because of the increasing recognition of chronic pain as a very common, debilitating condition that requires specialized care. Neuropathic pain (NeP) is a multifaceted, specialized form of chronic pain that often requires input from multiple disciplines for assessment and management.
To determine the impact of an interdisciplinary clinic for evaluation and treatment of patients with NeP.
Patients with heterogeneous etiologies for NeP were prospectively evaluated using an interdisciplinary approach every six months. Diagnostic evaluation, comorbidity evaluation, education, and pharmacological and/or nonpharmacological management were completed. Severity (visual analogue scale) and features of pain (Modified Brief Pain Inventory), sleep difficulties (Medical Outcomes Study – Sleep Scale), mood/anxiety disruption (Hospital Anxiety and Depression Scale), quality of life (European Quality-of-Life Five-Domain index), health care resources use, patient satisfaction (Pain Treatment Satisfaction Scale and Neuropathic Pain Symptom Inventory) and self-perceived change in well-being (Patient Global Impression of Change scale) were examined at each visit.
Pain severity only decreased after one year of follow-up, while anxiety and quality-of-life indexes improved after six months. Moderate improvements of sleep disturbance, less frequent medication use and reduced health care resource use were observed during enrollment at the NeP clinic.
Despite the limitations of performing a real-world, uncontrolled study, patients with NeP benefit from enrollment in a small interdisciplinary clinic. Education and a complete diagnostic evaluation are hypothesized to lead to improvements in anxiety and, subsequently, pain severity. Questions remain regarding the long-term maintenance of these improvements and the optimal structure of specialized pain clinics.
PMCID: PMC3198114  PMID: 21766065
Interdisciplinary clinic; Intervention; Medication; Neuropathic pain
15.  A Novel Tool for the Assessment of Pain: Validation in Low Back Pain 
PLoS Medicine  2009;6(4):e1000047.
Joachim Scholz and colleagues develop and validate an assessment tool that distinguishes between radicular and axial low back pain.
Adequate pain assessment is critical for evaluating the efficacy of analgesic treatment in clinical practice and during the development of new therapies. Yet the currently used scores of global pain intensity fail to reflect the diversity of pain manifestations and the complexity of underlying biological mechanisms. We have developed a tool for a standardized assessment of pain-related symptoms and signs that differentiates pain phenotypes independent of etiology.
Methods and Findings
Using a structured interview (16 questions) and a standardized bedside examination (23 tests), we prospectively assessed symptoms and signs in 130 patients with peripheral neuropathic pain caused by diabetic polyneuropathy, postherpetic neuralgia, or radicular low back pain (LBP), and in 57 patients with non-neuropathic (axial) LBP. A hierarchical cluster analysis revealed distinct association patterns of symptoms and signs (pain subtypes) that characterized six subgroups of patients with neuropathic pain and two subgroups of patients with non-neuropathic pain. Using a classification tree analysis, we identified the most discriminatory assessment items for the identification of pain subtypes. We combined these six interview questions and ten physical tests in a pain assessment tool that we named Standardized Evaluation of Pain (StEP). We validated StEP for the distinction between radicular and axial LBP in an independent group of 137 patients. StEP identified patients with radicular pain with high sensitivity (92%; 95% confidence interval [CI] 83%–97%) and specificity (97%; 95% CI 89%–100%). The diagnostic accuracy of StEP exceeded that of a dedicated screening tool for neuropathic pain and spinal magnetic resonance imaging. In addition, we were able to reproduce subtypes of radicular and axial LBP, underscoring the utility of StEP for discerning distinct constellations of symptoms and signs.
We present a novel method of identifying pain subtypes that we believe reflect underlying pain mechanisms. We demonstrate that this new approach to pain assessment helps separate radicular from axial back pain. Beyond diagnostic utility, a standardized differentiation of pain subtypes that is independent of disease etiology may offer a unique opportunity to improve targeted analgesic treatment.
Editors' Summary
Pain, although unpleasant, is essential for survival. Whenever the body is damaged, nerve cells detecting the injury send an electrical message via the spinal cord to the brain and, as a result, action is taken to prevent further damage. Usually pain is short-lived, but sometimes it continues for weeks, months, or years. Long-lasting (chronic) pain can be caused by an ongoing, often inflammatory condition (for example, arthritis) or by damage to the nervous system itself—experts call this “neuropathic” pain. Damage to the brain or spinal cord causes central neuropathic pain; damage to the nerves that convey information from distant parts of the body to the spinal cord causes peripheral neuropathic pain. One example of peripheral neuropathic pain is “radicular” low back pain (also called sciatica). This is pain that radiates from the back into the legs. By contrast, axial back pain (the most common type of low back pain) is confined to the lower back and is non-neuropathic.
Why Was This Study Done?
Chronic pain is very common—nearly 10% of American adults have frequent back pain, for example—and there are many treatments for it, including rest, regulated exercise (physical therapy), pain-killing drugs (analgesics), and surgery. However, the best treatment for any individual depends on the exact nature of their pain, so it is important to assess their pain carefully before starting treatment. This is usually done by scoring overall pain intensity, but this assessment does not reflect the characteristics of the pain (for example, whether it occurs spontaneously or in response to external stimuli) or the complex biological processes involved in pain generation. An assessment designed to take such factors into account might improve treatment outcomes and could be useful in the development of new therapies. In this study, the researchers develop and test a new, standardized tool for the assessment of chronic pain that, by examining many symptoms and signs, aims to distinguish between pain subtypes.
What Did the Researchers Do and Find?
One hundred thirty patients with several types of peripheral neuropathic pain and 57 patients with non-neuropathic (axial) low back pain completed a structured interview of 16 questions and a standardized bedside examination of 23 tests. Patients were asked, for example, to choose words that described their pain from a list provided by the researchers and to grade the intensity of particular aspects of their pain from zero (no pain) to ten (the maximum imaginable pain). Bedside tests included measurements of responses to light touch, pinprick, and vibration—chronic pain often alters responses to harmless stimuli. Using “hierarchical cluster analysis,” the researchers identified six subgroups of patients with neuropathic pain and two subgroups of patients with non-neuropathic pain based on the patterns of symptoms and signs revealed by the interviews and physical tests. They then used “classification tree analysis” to identify the six questions and ten physical tests that discriminated best between pain subtypes and combined these items into a tool for a Standardized Evaluation of Pain (StEP). Finally, the researchers asked whether StEP, which took 10–15 minutes, could identify patients with radicular back pain and discriminate them from those with axial back pain in an independent group of 137 patients with chronic low back pain. StEP, they report, accurately diagnosed these two conditions and was well accepted by the patients.
What Do These Findings Mean?
These findings indicate that a standardized assessment of pain-related signs and symptoms can provide a simple, quick diagnostic procedure that distinguishes between radicular (neuropathic) and axial (non-neuropathic) low back pain. This distinction is crucial because these types of back pain are best treated in different ways. In addition, the findings suggest that it might be possible to identify additional pain subtypes using StEP. Because these subtypes may represent conditions in which different pain mechanisms are acting, classifying patients in this way might eventually enable physicians to tailor treatments for chronic pain to the specific needs of individual patients rather than, as at present, largely guessing which of the available treatments is likely to work best.
Additional Information
Please access these Web sites via the online version of this summary at
This study is further discussed in a PLoS Medicine Perspective by Giorgio Cruccu and and Andrea Truini
The US National Institute of Neurological Disorders and Stroke provides a primer on pain in English and Spanish
In its 2006 report on the health status of the US, the National Center for Health Statistics provides a special feature on the epidemiology of pain, including back pain
The Pain Treatment Topics Web site is a resource, sponsored partly by associations and manufacturers, that provides information on all aspects of pain and its treatment for health care professionals and their patients
Medline Plus provides a brief description of pain and of back pain and links to further information on both topics (in English and Spanish)
The MedlinePlus Medical Encyclopedia also has a page on low back pain (in English and Spanish)
PMCID: PMC2661253  PMID: 19360087
16.  Neuropathic Pain in Breast Cancer Survivors: Using the ID Pain as a Screening Tool 
Neuropathic pain (NP) is a debilitating symptom experienced by a number of patients with cancer. We evaluated the validity of ID Pain as a screening tool for NP in breast cancer survivors using the S-LANSS and a reported diagnosis of NP as criterion measures. Two hundred and forty breast cancer survivors with a mean age of 58 years (SD= 16) participated in this survey. Forty-five percent of the sample reported having pain in the past week. Of those reporting pain, 33% reported that they had been diagnosed by their health care provider for NP, 39% had a positive ID Pain (≥ 2) score and 19% had a positive S-LANSS score. The most commonly endorsed ID Pain item was “hot/burning” (n = 48), followed by feeling “numb” (n = 47) and “pins and needles” (n = 45). Total ID Pain score was significantly associated with a clinical diagnosis of NP (r = 0.41; P < 0.001) and the S-LANSS total score (r = 0.54; P < 0.001). Receiver Operating Curve analysis demonstrated that ID Pain has a predictive validity of 0.72 and 0.70 for diagnosis of NP as made by clinicians and the S-LANSS, respectively. We also found that an ID Pain score of ≥ 2 corresponded with the likelihood of NP in this sample, consistent with the original ID Pain development study. This study provides evidence for ID Pain as a valid screening measure of NP for breast cancer survivors.
PMCID: PMC2872632  PMID: 20471548
Neuropathic pain; ID Pain; epidemiology; breast cancer; symptoms; survivorship
17.  Pharmacological management of chronic neuropathic pain – Consensus statement and guidelines from the Canadian Pain Society 
Neuropathic pain (NeP), generated by disorders of the peripheral and central nervous system, can be particularly severe and disabling. Prevalence estimates indicate that 2% to 3% of the population in the developed world suffer from NeP, which suggests that up to one million Canadians have this disabling condition. Evidence-based guidelines for the pharmacological management of NeP are therefore urgently needed. Randomized, controlled trials, systematic reviews and existing guidelines focusing on the pharmacological management of NeP were evaluated at a consensus meeting. Medications are recommended in the guidelines if their analgesic efficacy was supported by at least one methodologically sound, randomized, controlled trial showing significant benefit relative to placebo or another relevant control group. Recommendations for treatment are based on degree of evidence of analgesic efficacy, safety, ease of use and cost-effectiveness. Analgesic agents recommended for first-line treatments are certain antidepressants (tricyclics) and anticonvulsants (gabapentin and pregabalin). Second-line treatments recommended are serotonin noradrenaline reuptake inhibitors and topical lidocaine. Tramadol and controlled-release opioid analgesics are recommended as third-line treatments for moderate to severe pain. Recommended fourth-line treatments include cannabinoids, methadone and anticonvulsants with lesser evidence of efficacy, such as lamotrigine, topiramate and valproic acid. Treatment must be individualized for each patient based on efficacy, side-effect profile and drug accessibility, including cost. Further studies are required to examine head-to-head comparisons among analgesics, combinations of analgesics, long-term outcomes, and treatment of pediatric and central NeP.
PMCID: PMC2670721  PMID: 17372630
Analgesic agents; Neuropathic pain; Randomized controlled trials
18.  The importance of catastrophizing for successful pharmacological treatment of peripheral neuropathic pain 
Journal of Pain Research  2014;7:327-338.
Catastrophizing may be a negative predictor of pain-related outcomes. We evaluated the impact of catastrophizing upon success of first-line pharmacotherapy in the management of neuropathic pain (NeP) due to peripheral polyneuropathy.
Patients with confirmed NeP with NeP Visual Analog Scale (VAS) pain severity score ≥4 (0–10 scale) completed the Coping Strategies Questionnaire (CSQ) catastrophizing subscale at baseline. Pharmacological therapy consisting of first-line agents gabapentin, pregabalin, or a tricyclic antidepressant was initiated. Other measures examined included the Karnofsky Performance Scale, Beck Depression Inventory, EuroQol Quality of Life Health Questionnaire, and Modified Brief Pain Inventory. At 3 and 6 months, questionnaires were repeated and adverse effect reporting was completed. Outcome measures assessed were pharmacotherapy success (≥30% relief of NeP) and tolerability over 6 months of follow-up. Bivariate relationships using Pearson product-moment correlations were examined for baseline CSQ catastrophizing subscale score and the change in the NeP VAS scores and medication discontinuation.
Sixty-six patients were screened, 62 subjects participated, and 58 subjects (94%) completed the final follow-up visit. Greater catastrophizing was associated with poor pain relief response and greater likelihood of discontinuation of pharmacotherapy, reports of greater disability, and impaired quality of life. Duration of pain was negatively associated with likelihood of pharmacotherapy success.
Catastrophizing exerts maladaptive effects on outcomes with pharmacotherapy in NeP patients. Detection of catastrophizing during clinical visits when pharmacological therapy is being considered can be a predictive factor for patient outcomes.
PMCID: PMC4077695  PMID: 25028563
neuropathic pain; catastrophizing; coping; pharmacotherapy
19.  Health care utilization and expenditures among Medicaid beneficiaries with neuropathic pain following spinal cord injury 
Journal of Pain Research  2014;7:379-387.
The study aimed to evaluate health care resource utilization (HRU) and costs for neuropathic pain (NeP) secondary to spinal cord injury (SCI) among Medicaid beneficiaries.
The retrospective longitudinal cohort study used Medicaid beneficiary claims with SCI and evidence of NeP (SCI-NeP cohort) matched with a cohort without NeP (SCI-only cohort). Patients had continuous Medicaid eligibility 6 months pre- and 12 months postindex, defined by either a diagnosis of central NeP (ICD-9-CM code 338.0x) or a pharmacy claim for an NeP-related antiepileptic or antidepressant drug within 12 months following first SCI diagnosis. Demographics, clinical characteristics, HRU, and expenditures were compared between cohorts.
Propensity score-matched cohorts each consisted of 546 patients. Postindex percentages of patients with physician office visits, emergency department visits, SCI- and pain-related procedures, and outpatient prescription utilization were all significantly higher for SCI-NeP (P<0.001). Using regression models to account for covariates, adjusted mean expenditures were US$47,518 for SCI-NeP and US$30,150 for SCI only, yielding incremental costs of US$17,369 (95% confidence interval US$9,753 to US$26,555) for SCI-NeP. Factors significantly associated with increased cost included SCI type, trauma-related SCI, and comorbidity burden.
Significantly higher HRU and total costs were incurred by Medicaid patients with NeP secondary to SCI compared with matched SCI-only patients.
PMCID: PMC4085322  PMID: 25061337
spinal cord injuries; burden of illness
20.  Is there a role for Gabapentin in preventing or treating pain following thoracic surgery? 
A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was whether gabapentin, a commonly prescribed neuropathic analgesic and anticonvulsant, is safe and beneficial in patients with post-thoracotomy pain following thoracic surgery. Seventeen papers were identified using the search described below, and five papers presented the best evidence to reach conclusions regarding the issues of interest for this review. Side effects and complications as well as evidence of benefit, typically using various pain-scoring systems, were included in the assessment. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of the papers are tabulated. The systematic review of two randomized controlled trials (RCTs) demonstrated that the use of a single dose gabapentin does not reduce pain scores or the need for epidural or morphine immediately in hospital following thoracic surgery. One double-blinded RCT used multiple doses of gabapentin perioperatively and showed that oral gabapentin administered preoperatively and during the first 2 days postoperatively, in conjunction with patient controlled analgesia morphine, provides effective analgesia in thoracic surgery with a consequent improvement in postoperative pulmonary function and less morphine consumption. One prospective clinical study comparing a 2-month course of gabapentin with naproxen sodium for chronic post thoracotomy pain following surgery showed significant improvement in both the visual analogue scale (VAS) score and the Leeds assessment of neuropathic symptoms and signs (LANSS) at 60 days in the gabapentin (P = 0.001). One prospective study of out-patients with chronic pain (>4 weeks since thoracotomy performed) suggested that gabapentin is effective, safe and well tolerated when used for persistent postoperative and post-traumatic pain in thoracic surgery patients. We conclude that there is no evidence to support the role of a single preoperative oral dose of gabapentin in reducing pain scores or opioid consumption following thoracic surgery. Multiple dosing regimens may be beneficial in reducing acute and chronic pain; however, more robust randomized control studies are needed.
PMCID: PMC3781811  PMID: 23832920
Gabapentin; Safety; Thoracotomy; Pain
21.  Investigating the role of neuropathic pain relief in decreasing gait variability in diabetes mellitus patients with neuropathic pain: a randomized, double-blind crossover trial 
Subjects with diabetes mellitus (DM) develop gait dysfunction contributing to falls, reluctance to perform activities and injuries. Neuropathic pain (NeP) related to diabetic peripheral neuropathy (DPN) is associated with increased gait variability that may contribute to gait dysfunction. We used a portable device (GaitMeter™) and related gait and balance measures to measure gait parameters in painful DPN (PDPN) subjects prior to and during analgesia. Our hypothesis was that PDPN subjects would have decreased gait step variability when receiving pharmacological relief of NeP.
DPN subjects with at least moderate NeP were assessed in a randomized, double-blind crossover study of pregabalin versus placebo. The outcome measure was variability in step length and step velocity. Testing for Timed Get-Up-and-Go Test, Tinetti Mobility Scales, Sway Testing, a Physiological Profile Approach, and fall-related surveys were also performed. DPN severity was quantified using the Utah Early Neuropathy Score.
PDPN subjects developed increased, rather than decreased, step length and step velocity variability during pregabalin treatment. There were no significant differences between cohorts for other physiological gait and balance testing. Non-significant NeP relief occurred in the pregabalin phase of study as compared with placebo. There was a negative relationship for step length with pain severity.
Analgesia did not decrease gait variability in PDPN patients, and in fact, increased gait variability was seen during pregabalin treatment. Other important relationships of gait dysfunction with PDPN should be sought.
Electronic supplementary material
The online version of this article (doi:10.1186/1743-0003-11-125) contains supplementary material, which is available to authorized users.
PMCID: PMC4150964  PMID: 25139539
Type 2 diabetes mellitus; Gait; Diabetic neuropathy; Diabetic neuropathic pain; Pregabalin
22.  A Cost-Consequences analysis of the effect of Pregabalin in the treatment of peripheral Neuropathic Pain in routine medical practice in Primary Care settings 
BMC Neurology  2011;11:7.
Neuropathic pain (NeP) is a common symptom of a group of a variety of conditions, including diabetic neuropathy, trigeminal neuralgia, or postherpetic neuralgia. Prevalence of NeP has been estimated to range between 5-7.5%, and produces up to 25% of pain clinics consultations. Due to its severity, chronic evolution, and associated co-morbidities, NeP has an important individual and social impact. The objective was to analyze the effect of pregabalin (PGB) on pain alleviation and longitudinal health and non-health resources utilization and derived costs in peripheral refractory NeP in routine medical practice in primary care settings (PCS) in Spain.
Subjects from PCS were older than 18 years, with peripheral NeP (diabetic neuropathy, post-herpetic neuralgia or trigeminal neuralgia), refractory to at least one previous analgesic, and included in a prospective, real world, and 12-week two-visit cost-of-illness study. Measurement of resources utilization included both direct healthcare and indirect expenditures. Pain severity was measured by the Short Form-McGill Pain Questionnaire (SF-MPQ).
One-thousand-three-hundred-fifty-four PGB-naive patients [58.8% women, 59.5 (12.7) years old] were found eligible for this secondary analysis: 598 (44%) switched from previous therapy to PGB given in monotherapy (PGBm), 589 (44%) received PGB as add-on therapy (PGB add-on), and 167 (12%) patients changed previous treatments to others different than PGB (non-PGB). Reductions of pain severity were higher in both PGBm and PGB add-on groups (54% and 51%, respectively) than in non-PGB group (34%), p < 0.001. Incremental drug costs, particularly in PGB subgroups [€34.6 (80.3), €160.7 (123.9) and €154.5 (133.0), for non-PGB, PGBm and PGBadd-on, respectively (p < 0.001)], were off-set by higher significant reductions in all other components of health costs yielding to a greater total cost reductions: -€1,045.3 (1,989.6),-€1,312.9 (1,543.0), and -€1,565.5 (2,004.1), for the three groups respectively (p = 0.03).
In Spanish primary care settings, PGB given either add-on or in monotherapy in routine medical practice was associated with pain alleviation leading to significant longitudinal reductions in resource use and total costs during the 12-week period of the study compared with non-PGB-therapy of patients with chronic NeP of peripheral origin. The use of non-appropriate analgesic therapies for neuropathic pain in a portion of subjects in non-PGB group could explain partially such findings.
PMCID: PMC3037328  PMID: 21251268
23.  An investigation of somatosensory profiles in work related upper limb disorders: a case-control observational study protocol 
Work related upper limb disorders constitute 45% of all occupational diseases and are a significant public health problem. A subgroup, non specific arm pain (NSAP), remains elusive in terms of understanding its pathophysiological mechanisms with its diagnosis based on the absence of specific clinical findings. One commonly proposed theory is that a neural tissue disorder is the primary dysfunction in NSAP and findings from previous studies lend some support to this theory. However, it is not clear if changes identified are simply a consequence of ongoing pain rather than due to specific neural changes. The presence of neuropathic pain has been investigated in several other musculoskeletal conditions but currently, there is no specific diagnostic tool or gold standard which permits an unequivocal diagnosis of neuropathic pain. The purpose of this study is to further describe the somatosensory profiles in patients with NSAP and to compare these profiles to a group of patients with MRI confirmed cervical radiculopathy who have been previously classified as having neuropathic pain.
Three groups of participants will be investigated: Groups 1 and 2 will be office workers with either NSAP or cervical radiculopathy and Group 3 will be a control group of non office workers without upper limb pain. Participants will undergo a clinical assessment, pain questionnaires (LANSS, Short Form McGill, DASH and TSK) and quantitative sensory testing comprising thermal detection and pain thresholds, vibration thresholds and pressure pain thresholds.
The spectrum of clinically suspected neuropathic pain ranges from more obvious conditions such as trigeminal neuralgia to those with vague signs of nerve disorder such as NSAP. A thorough description of the somatosensory profiles of NSAP patients and a comparison with a more defined group of patients with evidence of neuropathic pain will help in the understanding of underlying neurophysiology in NSAP and may influence future classification and intervention studies relating to this condition.
PMCID: PMC2825226  PMID: 20113518
24.  Pregabalin, the lidocaine plaster and duloxetine in patients with refractory neuropathic pain: a systematic review 
BMC Neurology  2010;10:116.
Patients frequently fail to receive adequate pain relief from, or are intolerant of, first-line therapies prescribed for neuropathic pain (NeP). This refractory chronic pain causes psychological distress and impacts patient quality of life. Published literature for treatment in refractory patients is sparse and often published as conference abstracts only. The aim of this study was to identify published data for three pharmacological treatments: pregabalin, lidocaine plaster, and duloxetine, which are typically used at 2nd line or later in UK patients with neuropathic pain.
A systematic review of the literature databases MEDLINE, EMBASE and CCTR was carried out and supplemented with extensive conference and grey literature searching. Studies of any design (except single patient case studies) that enrolled adult patients with refractory NeP were included in the review and qualitatively assessed.
Seventeen studies were included in the review: nine of pregabalin, seven of the lidocaine plaster, and one of duloxetine. No head-to-head studies of these treatments were identified. Only six studies included treatments within UK licensed indications and dose ranges. Reported efficacy outcomes were not consistent between studies. Pain scores were most commonly assessed in studies including pregabalin; trials of pregabalin and the lidocaine plaster reported the proportion of responders. Significant improvements in the total, sensory and affective scores of the Short-form McGill Pain Questionnaire, and in function interference, sleep interference and pain associated distress, were associated with pregabalin treatment; limited or no quality of life data were available for the other two interventions. Limitations to the review are the small number of included studies, which are generally small, of poor quality and heterogeneous in patient population and study design.
Little evidence is available relevant to the treatment of refractory neuropathic pain despite the clinical need. There is a notable lack of high-quality comparative studies. It is evident that there is a need for future, high quality trials, particularly "gold-standard" RCTs in this refractory patient population.
PMCID: PMC3003252  PMID: 21092100
25.  Characteristics of Neuropathic Pain in Patients With Spinal Cord Injury 
Annals of Rehabilitation Medicine  2014;38(3):327-334.
To characterize neuropathic pain in patients with spinal cord injury (SCI) according to classification used in the study by Baron et al. (Baron classification), a classification of neuropathic pain based on the mechanism. To also compare the patterns of neuropathic pain in SCI patients with those in patients with other etiologies and to determine the differences in patterns of neuropathic pain between the etiologies.
This was a descriptive cross-sectional study. We used the Baron classification to investigate the characteristics of neuropathic pain in SCI. Sixty-one SCI patients with neuropathic pain (The Leeds assessment of neuropathic symptoms and signs score ≥12) were enrolled in this study between November 2012 and August 2013, after excluding patients <20 of age, patients with visual analog scale (VAS) score <3, pregnant patients, and patients with systemic disease or pain other than neuropathic pain.
The most common pain characteristic was pricking pain followed by electrical pain and numbness. The mean VAS score of at-level neuropathic pain was 7.51 and that of below-level neuropathic pain was 6.83. All of the patients suffered from rest pain, but 18 (54.6%) patients with at-level neuropathic pain and 20 (50.0%) patients with below-level neuropathic pain suffered from evoked pain. There was no significant difference in between at-level and below-level neuropathic pains.
The result was quite different from the characteristics of post-herpetic neuralgia, but it was similar to the characteristics of diabetic neuropathy as shown in the study by Baron et al., which means that sensory nerve deafferentation may be the most common pathophysiologic mechanism of neuropathic pain after SCI. Since in our study, we included short and discrete symptoms and signs based on diverse mechanisms, our results could be helpful for determining further evaluation and treatment.
PMCID: PMC4092172  PMID: 25024955
Neuralgia; Spinal cord injuries; Classification

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