Neuropathic Features Research Articles

Neuropathic pain in leprosy

Nerve impairment is a key clinical aspect of leprosy and may present the distribution of mononeuropathy or multiple nerve trunks, small cutaneous nerve fibers, and free nerve endings. The clinical range of leprosy is determined by individual cell-mediated immune response to infection that also may play a role in different types of pain syndromes in leprosy. Previous studies reported a high prevalence of neuropathic pain in leprosy. In an Ethiopian study with 48 patients, pure nociceptive pain was experienced by 43% of patients and pure neuropathic pain (NeP) by 11% of patients. In an Indian study, 21.8% of leprosy patients had pain with neuropathic characteristics. These rates underlie the need to develop tools for the early diagnosis and detection of infection and its complications, such as nerve damage and pain. In a larger sample with leprosy-associated NeP (n = 90), we have applied the Douleur Neuropathique en 4 questions (DN4) and found sensitivity = 97.1% and specificity = 57.9%. The high sensitivity of this tool in leprosy patients suggests that it could be a valuable tool to screen for neuropathic pain in this population and could be used as part of health care programs aimed at detecting, treating, and rehabilitating leprosy in endemic areas.

Use of neuropathic pain questionnaires in predicting persistent postoperative neuropathic pain following lumbar discectomy for radiculopathy.

OBJECT Failed-back surgery syndrome has been historically used to describe extremity neuropathic pain in lumbar disease despite structurally corrective spinal surgery. It is unclear whether specific preoperative pain characteristics can help determine which patients may be susceptible to such postoperative disabling symptoms. METHODS This prospective study analyzed surgical microdiscectomy patients treated for lumbar, degenerative, painful radiculopathy. Clinical parameters included general demographics, preoperative and postoperative clinical examination status, self-reported pain and disability scores, and neuropathic pain scores. The screening tests for neuropathic pain were the Douleur Neuropathique 4 and Leeds Assessment of Neuropathic Symptoms and Signs, with correlation tested for ordinal score and screen positivity. Multiple logistic regression analysis was used to define predictors of postoperative symptomatology. RESULTS Twelve percent of the 250 patients with radiculopathy who underwent microdiscectomy experienced persistent postoperative neuropathic pain (PPNP) with only modest, if any, relief of leg pain. The condition was highly associated with abnormal preoperative screen results for neuropathic pain, but not sex, smoking status, or preoperative pain severity (α = 0.05). Good correlation was seen between the 2 screening tests used in this study for both absolute ordinal score (Spearman ρ = 0.84; p < 0.001) and the threshold for terming the patient as having neuropathic pain features (Spearman ρ = 0.48; p < 0.001). Younger age at treatment also correlated with a higher likelihood of developing PPNP (p = 0.03). CONCLUSIONS This population exhibited a low overall frequency of PPNP. Higher neuropathic pain screening scores correlated strongly with likelihood of significant postoperative leg pain. Further work is required to develop more accurate prognostication tools for radiculopathy patients undergoing structural spinal surgery.

Chronic postsurgical pain in Europe: An observational study.

Chronic postsurgical pain (CPSP) is an important clinical problem. Prospective studies of the incidence, characteristics and risk factors of CPSP are needed. The objective of this study is to evaluate the incidence and risk factors of CPSP. A multicentre, prospective, observational trial. Twenty-one hospitals in 11 European countries. Three thousand one hundred and twenty patients undergoing surgery and enrolled in the European registry PAIN OUT. Pain-related outcome was evaluated on the first postoperative day (D1) using a standardised pain outcome questionnaire. Review at 6 and 12 months via e-mail or telephonic interview used the Brief Pain Inventory (BPI) and the DN4 (Douleur Neuropathique four questions). Primary endpoint was the incidence of moderate to severe CPSP (numeric rating scale, NRS ≥3/10) at 12 months. For 1044 and 889 patients, complete data were available at 6 and 12 months. At 12 months, the incidence of moderate to severe CPSP was 11.8% (95% CI 9.7 to 13.9) and of severe pain (NRS ≥6) 2.2% (95% CI 1.2 to 3.3). Signs of neuropathic pain were recorded in 35.4% (95% CI 23.9 to 48.3) and 57.1% (95% CI 30.7 to 83.4) of patients with moderate and severe CPSP, respectively. Functional impairment (BPI) at 6 and 12 months increased with the severity of CPSP (P < 0.01) and presence of neuropathic characteristics (P < 0.001). Multivariate analysis identified orthopaedic surgery, preoperative chronic pain and percentage of time in severe pain on D1 as risk factors. A 10% increase in percentage of time in severe pain was associated with a 30% increase of CPSP incidence at 12 months. The collection of data on CPSP was feasible within the European registry PAIN OUT. The incidence of moderate to severe CPSP at 12 months was 11.8%. Functional impairment was associated with CPSP severity and neuropathic characteristics. Risk factors for CPSP in the present study were chronic preoperative pain, orthopaedic surgery and percentage of time in severe pain on D1. Clinicaltrials.gov identifier: NCT01467102.

Predictors of Persistent Neuropathic Pain – A Systematic Review

Background: Characterization of the prognostic variables for persistent neuropathic pain (PNP) remains incomplete despite multiple articles addressing this topic. To provide more insight into the recovery and prognosis of neuropathic pain, high-quality data are required that provide information about the predictors that contribute to the development of PNP. Objective: To determine the methodological quality of studies about predictors for PNP and to summarize findings of predictors found in high-quality studies. Study Design: A systematic review. Setting: VU University Medical Center, Amsterdam, The Netherlands. Methods: Studies were identified by searching the electronic databases PubMed, Embase, and Cochrane Library. Methodological quality of each article was independently assessed by 2 reviewers. Results: Forty-six relevant studies were identified, classified into 4 different neuropathic pain (NP)- syndromes: postherpetic neuralgia (n = 35), radicular pain and sciatica (n = 3), postsurgical pain (n = 6), and other types of NP (n = 2). Seven studies were of high quality. The 3 high-quality studies found for PHN reported male gender, older age, smoking, trauma at the site of lesion, missed antiviral prescriptions, higher acute pain severity, higher rash severity, more neuropathic characteristics, shorter rash duration, and a lower health status as predictors for PNP. For persistence of radicular pain one high-quality study reported negative outcome expectancies, pain-related fear of movement, and passive pain coping as predictors for PNP. Psychological distress, acute pain, breast cancer surgery, higher body mass index, area of secondary hyperalgesia, neuropathic characteristics, hypoesthesia, and hyperesthesia were found to be predictive for postsurgical pain in 3 high-quality studies. Limitations: Some publications may have been missed during literature search. The low-quality of the studies could be the result of an incomplete description of their methods. Conclusions: High-quality studies mainly assessed factors related to disease functions and structures. Due to shortcomings in methodological quality and limited areas of predictor selection, there is a need for high-quality studies focusing on predictor measurement, statistical analysis and the use of a standardized set of predictors. Key words: Neuropathic pain, persistent pain, systematic review, literature search, predictors, quality assessment, ICF-model

Neuropathic-like pain features and cross-sectional associations in rheumatoid arthritis.

IntroductionIncreasing evidence indicates that features suggestive of neuropathic pain may also be present in patients with common rheumatic conditions. The objective of this study was to examine neuropathic-like pain symptoms and associated factors in patients with rheumatoid arthritis.MethodsWe used the painDETECT screening tool to identify possible or likely neuropathic pain in 159 outpatients with rheumatoid arthritis. Patients additionally completed other self-reported measures, while clinical measures were assessed to calculate the 28-joint Disease Activity Score. Univariate analyses and multivariable logistic regression were used to identify factors associated with neuropathic pain features.ResultsAccording to the painDETECT, 27 patients (17.0 %) were classified as having likely neuropathic pain and 34 patients (21.4 %) as having possible neuropathic pain. Besides reporting more severe pain, patients with likely or possible neuropathic pain were more likely to meet the diagnostic criteria for fibromyalgia, to use analgesics, and to have more tender joints and a worse physical and mental health status as measured by the 36-item Short-Form health survey. In multivariable analysis, physical (P < 0.001) and mental health status (P = 0.006) remained significantly associated with neuropathic pain features, even after controlling for pain severity.ConclusionsThese findings suggest that a sizeable proportion of patients with relatively well-controlled rheumatoid arthritis report symptoms suggestive of neuropathic pain. Neuropathic-like pain symptoms are independently associated with worse self-reported physical and mental health.

The Role of Psychological Factors in Persistent Pain After Cesarean Delivery

This French multicenter prospective cohort study recruited 391 patients to investigate the risk factors for persistent pain after elective cesarean delivery, focusing on psychosocial aspects adjusted for other known medical factors. Perioperative data were collected and specialized questionnaires were completed to assess reports of pain at the site of surgery. Three dependent outcomes were considered: pain at the third month after surgery (M3, n = 268; risk = 28%), pain at the sixth month after surgery (M6, n = 239; risk = 19%), and the cumulative incidence (up to M6) of neuropathic pain, as assessed using the Douleur Neuropathique 4 questionnaire (n = 218; risk = 24.5%). The neuropathic aspect of reported pain changed over time in more than 60% of cases, pain being more intense if associated with neuropathic features. Whatever the dependent outcome, a high mental component of quality of life (SF-36) was protective. Pain at M3 was also predicted by pain reported during current pregnancy and a history of miscarriage. Pain at M6 was also predicted by report of a postoperative complication. Incident neuropathic pain was predicted by pain reported during current pregnancy, a previous history of a peripheral neuropathic event, and preoperative anxiety. Trial RegistrationClinicalTrials.gov, NCT00812734. PerspectivePersistent pain after cesarean delivery has a relatively frequent neuropathic aspect but this is less stable than that after other surgeries. When comparing the risk factor analyses with published data for hysterectomy, the influence of preoperative psychological factors seems less important, possibly because of the different context and environment.

Is there pain with neuropathic characteristics in patients with amyotrophic lateral sclerosis? A cross-sectional study

Background: Amyotrophic lateral sclerosis is a progressive debilitating and lethal disorder, characterized by degeneration of motor neurons that warrant palliative care. Pain is frequent in patients with amyotrophic lateral sclerosis and significantly impacts on quality of life. Aim: To describe pain and assess the prevalence of pain with neuropathic characteristics in patients with amyotrophic lateral sclerosis. Design: Cross-sectional survey from March 2009 to October 2013. Setting/participants: Amyotrophic lateral sclerosis patients underwent multidisciplinary assessment and completed questionnaires measuring the severity and impact of pain and anxiety. The Douleur Neuropathique–4 questionnaire was used to look for pain with neuropathic characteristics. Results: Of 96 clinical evaluations, 93 were usable for analysis (age at onset: 62 ± 12.5 years; disease duration: 34 ± 33 months). The overall pain prevalence was 66%, with 9% experiencing pain with neuropathic characteristics. Pain was most often located in the neck and shoulders (38% of pain patients). Neck and shoulder pain was associated with neck (p = 0.04) and proximal upper limb muscular weakness (p = 0.02), respectively. Pain was not associated with disease duration, respiratory or nutritional parameters, but with higher anxiety scores (p = 0.01). Patients with neuropathic characteristics pain did not differ significantly from patients with or without pain, except that they had higher minimal pain intensity score (p < 0.05). Neuropathic characteristics pain was frequently spontaneous (rarely evoked) and described as numbness, burning, electric shock, tingling, and pins-and-needle. Conclusion: Even if amyotrophic lateral sclerosis is a disease of the motor system, pain is frequent and can rarely have neuropathic characteristics. Pain must be always sought and appropriately treated to limit quality of life impairment.

Neuroinflammation in the peripheral nerve: Cause, modulator, or bystander in peripheral neuropathies?

The role of innate and adaptive inflammation as a primary driver or modifier of neuropathy in premorbidly normal nerves, and as a critical player in amplifying neuropathies of other known causes (e.g., genetic, metabolic) is incompletely understood and under‐researched, despite unmet clinical need. Also, cellular and humoral components of the adaptive and innate immune system are substantial disease modifying agents in the context of neuropathies and, at least in some neuropathies, there is an identified tight interrelationship between both compartments of the immune system. Additionally, the quadruple relationship between Schwann cell, axon, macrophage, and endoneurial fibroblast, with their diverse membrane bound and soluble signalling systems, forms a distinct focus for investigation in nerve diseases with inflammation secondary to Schwann cell mutations and possibly others. Identification of key immunological effector pathways that amplify neuropathic features and associated clinical symptomatology including pain should lead to realistic and timely possibilities for translatable therapeutic interventions using existing immunomodulators, alongside the development of novel therapeutic targets. GLIA 2016;64:475–486

Differences in Neural Mechanosensitivity Between Patients with Chronic Nonspecific Neck Pain With and Without Neuropathic Features. A Descriptive Cross-Sectional Study.

To assess differences in neural mechanosensitivity between patients with chronic nonspecific neck pain with and without neuropathic features (NF and No-NF, respectively). Descriptive, cross-sectional study. A primary care center, a hospital physiotherapy outpatient department, and a university campus. Chronic nonspecific neck pain patients classified by the self-completed leeds assessment of neuropathic symptoms and signs pain scale (S-LANSS; 49 patients with NF [S-LANSS ≥ 12] and 50 patients with No-NF [S-LANSS < 12]) and a healthy control group (n = 48). The primary measurements were the mechanosensitivity of the median nerve and cervical region, specifically the assessment of the onset of symptoms and submaximal pain intensity according to the upper limb neural test 1 (ULNT1) for the median nerve and the modified passive neck flexion test (MPNFT) for the cervical region; secondary measurements included pain intensity, neck disability, kinesiophobia, and pain catastrophizing. Statistically significant differences between the NF and No-NF groups were found with respect to the onset of symptoms of ULNT1 (-15.11 [-23.19 to -7.03]) and MPNFT (-6.58 [-11.54 to -1.62]), as well as the outcomes of the visual analogue scale (Mean difference [95% Confidence Interval]; 7.12 [1.81-12.42]) and neck disability index (3.72 [1.72-5.71]). Both chronic nonspecific neck pain groups showed statistically significant differences compared with the control group for all outcomes assessed (P < 0.01) except for the onset of symptoms of ULNT1 in the No-NF group. The findings of this study suggest that chronic nonspecific neck pain patients with NF have greater neural mechanosensitivity, pain intensity, and neck disability than those with No-NF.

Neuropathic pain as part of chronic widespread pain: environmental and genetic influences.

Chronic widespread pain (CWP) has complex aetiology and forms part of the fibromyalgia syndrome. Recent evidence suggests a higher frequency of neuropathic pain features in those with CWP than previously thought. The aim of this study was to determine the prevalence of neuropathic pain features in individuals with CWP and to estimate the influence of genetic and environmental factors on neuropathic pain in CWP. Validated questionnaires (the London Fibromyalgia Screening Study questionnaire and PainDETECT questionnaire) were used to classify twins as having CWP and neuropathic pain, respectively. The prevalence of CWP was 14.7% (n = 4324), and of the 1357 twins invited to complete neuropathic pain screening, 15.9% of those having CWP demonstrated features of neuropathic pain. Neuropathic pain was found to be heritable (A = 37%; 95% confidence interval [CI]: 23%-50%) with unique environmental factors accounting for 63% (95% CI: 49%-79%) of the variance. Heritability of neuropathic pain and CWP were found to be correlated, 0.54 (95% CI: 0.42-0.65). Increasing age, raised body mass index, female gender, and smoking were all risk factors for neuropathic pain (P < 0.05), and CWP (P < 0.05). High socioeconomic status showed negative correlation with neuropathic pain (P = 0.003) and CWP (P = 0.001). Bivariate analysis of the 2 pain traits revealed that genetic predisposition to neuropathic pain is shared with that for CWP. This is the first study to provide formal heritability estimates for neuropathic pain in CWP. The findings suggest that at least some of the genetic factors underlying the development of neuropathic pain and CWP are the same.

World Health Organization essential medicines lists: where are the drugs to treat neuropathic pain?

Kamerman, Peter R.a,*; Wadley, Antonia L.a; Davis, Karen D.b; Hietaharju, Akic; Jain, Parmanandd; Kopf, Andrease; Meyer, Ana-Clairef; Raja, Srinivasa N.g; Rice, Andrew S. C.h; Smith, Blair H.i; Treede, Rolf-Detlefj; Wiffen, Philip J.k Author Information

Use of neuropathic pain questionnaires in predicting the development of failed back surgery syndrome following lumbar discectomy for radiculopathy

Objective: Failed back surgery syndrome (FBSS) describes neuropathic pain that occurs when extremity symptoms in lumbar disease persist despite structurally corrective spinal surgery. It is unclear whether specific preoperative pain characteristics predict patients prone to such postoperative disabling symptoms. Methods: This prospective study analyzed surgical patients with painful radiculopathy secondary to lumbar degenerative disease. Clinical parameters included general demographic information, preoperative and postoperative clinical examination, self-reported pain and disability scores, and neuropathic pain scoring. The neuropathic pain screening tests used in this study were the Douleur Neuropathique 4 (DN4) and Leeds Assessment of Neuropathic Symptoms and Signs (LANSS), with correlation tested for ordinal score and screen positivity. Multiple logistic regression analysis defined predictors of postoperative symptomatology. Results: Among 250 surgical radiculopathy patients, 12% were classified with FBSS. The condition was highly associated with abnormal preoperative screens for neuropathic pain, but not gender, smoking status, or preoperative pain severity (multiple logistic regression, α=0.05). Good correlation was seen between the two screening tests used in this study for absolute ordinal score (Spearman’s ρ=0.84, p&lt;0.001) and thresholding for neuropathic pain features (Spearman’s ρ=0.48, p&lt;0.001). Conclusion: Higher neuropathic pain screening scores correlated with likelihood of postoperative leg pain. Further work will develop more accurate prognostication tools for radiculopathy patients undergoing structural spinal surgery.

PP09.10 – 2510: A novel case of periaxin-related neuropathy associated with cataract: Expanding the clinical and molecular spectrum of perxiaxin mutation

Objective Periaxin gene (PRX) is responsible for autosomal recessive early onset demyelinlating neuropathy: Charcot-Marie Tooth disease 4F (CMT4F) or its severe form Dejerine Sottas neuropathy (DSN). Periaxin protein is essential for maintenance of the peripheral nerve myelin probably in stabilizing its structure. It also functions as a scaffold protein that plays a role in lens membrane organization and cell adhesive interactions. Methods Exome sequencing. Results This report describes a child of non-consanguineous healthy parents with delayed motor milestones, frequent falls, and subcapsular cataract. His neurological exam revealed typical neuropathic features of the lower extremities: weakness of the lower limbs accompanied by absence of deep tendon reflexes. There was no sensory deficiency though he walked on abroad basis. Even so, his motor functions have improved over the years. Nerve conduction velocity (NCV) demonstrated demyelinating process with secondary axonal damage. Bilateral sub capsular cataract was discovered at one year old with no other ophthalmic pathology. A novel homozygote frame shift mutation c.418-419insG (P.m 149 fs) in the PRX gene was identified by whole exome sequencing and was confirmed by molecular analysis. Both his parents were found to be heterozygote carriers of this mutation. Conclusion Mutation in the periaxin protein is most probably the cause of peripheral distal neuropathy and cataract in this child. As of today, cataracts caused by mutations in the PRX gene were demonstrated only in laboratory animals. This is the first description of human congenital neuropathy coexistence with congenital cataract caused by mutations in the PRX gene. This is a new clinical presentation of PRX related hereditary neuropathy. It is suggested that careful eye examination should be done in every patients with congenital neuropathy. The coexistence of neuropathy and cataract may direct to the final diagnosis and its genetic cause.

The Population Burden of Chronic Symptoms that Substantially Predate the Diagnosis of a Life-Limiting Illness.

Many people in our communities live with symptoms for years or decades, something of relevance to hospice/palliative care clinicians and researchers. The proportion of people in the community at large who have a chronic symptom is likely to approximate the proportion of people referred to hospice/palliative care services with that same chronic symptom that pre-dates their life-limiting illness. Such patients may have different responsiveness to, and expectations from, symptomatic therapies, thus requiring more advanced approaches to symptom control. For researchers evaluating the impact of hospice/palliative care services, failing to account for people with long-term refractory symptoms pre-dating their life-limiting illness may systematically underestimate services' benefits. Observational symptom prevalence studies reported in hospice/palliative care to date have not accounted for people with long-term refractory symptoms, potentially systematically overestimating symptoms attributed to life-limiting illnesses. Cross-sectional community prevalence rates of key chronic refractory symptoms largely unrelated to their life-limiting illness reflect the likely prevalence on referral to hospice/palliative care: fatigue (up to 35%); pain (12%-31%); pain with neuropathic characteristics (9%); constipation (2%-29%); dyspnea (4%-9%); cognitive impairment (>10% of people >65 years old; >30% of people >85 years old); anxiety (4%); and depression (lifetime incidence 2%-15%; one year prevalence 3%). Prospective research is needed to establish (1) the prevalence and severity of chronic symptoms that pre-date the diagnosis of a life-limiting illness in people referred to hospice/palliative care services, comparing this to whole-of-population estimates; and (2) whether this group is disproportionately represented in people with refractory symptoms.

Neuropathic caner pain: is it linked to the recurrence of cancer?

Cancer is a significant public health problem in every country. The World Health Organization reported that there were 14.1 million new cancer cases, 8.2 million cancer deaths, and 32.6 million people living with cancer (within 5 years of diagnosis) worldwide in 2012 [1]. The number of cancer survivors will increase due to improvement in cancer screening, advancement of cancer treatment, and the aging of the population [2,3]. Pain is a common symptom in cancer survivors [4]. In a systemic review [5], the reported incidence of was 33% to 64%. About one-third of the patients with presented their as moderate to severe. They may have acute and chronic related to direct tumor involvement, diagnostic or therapeutic procedures, or adverse effects of cancer treatment. They may also experience unrelated to cancer. Cancer can be classified predominant type of pain: either nociceptive or neuropathic. In clinical situation, cancer patients commonly experience more than one type of pain. They may represent both nociceptive and neuropathic features, rather than distinct elements of a single process. Neuropathic is defined as pain arising as a direct consequence of a lesion or disease affecting the somatosensory system [6]. Neuropathic cancer (NCP) is common and can be caused by direct tumor damage or as a consequence of cancer-directed therapy. In a recent systemic review, the prevalence of patients with NCP ranged from 19%-39.1%, including mixed as well as pure neuropathic pain. And, the causes of neuropathic cancer were cancer itself (64%), treatment of cancer (20.3%), related to cancer (3.5%), unrelated to the cancer (10.2%), and unknown origin (2%) [7]. Clinical characteristics of NCP include spontaneous burning, stabbing, or lancinating characteristics, hyperalgesia, and allodynia. Whatever the etiology of NCP is, it definitely arises from changes initiating in the damaged nerves, which in turn alter spinal cord and brain function, leading to altered plasticity at a number of sites [8]. The management of NCP may be therapeutically challenging. The pharmacotherapy, using combination of drugs with different mechanisms of action is a main therapeutic strategy. However, multimodal treatment, employing pharmacological therapy, nonpharmacological techniques, and psychological support, may be required to improve the quality of life along with sleep and mood. In this issue of the Korean Journal of Pain, Srivastava et al. [9] present the relationship between persistent post-radiotherapy and loco-regional recurrence in head and neck cancer patients.In the current study, 38.3% of patients with persistent had loco-regional recurrence, compared to 2.56% of patients in whom subsided. Furthermore, they showed that there was a significant benefit with regards to survival in patients who did not have persistent pain. In addition, the prevalence of NCP reported 17.4% and, more than 60% of the patients who had NCP at 6 weeks after radiotherapy experienced recurrence during follow-up. Therefore, the authors showed that identifying patients experiencing persistent during outpatient follow-up visits would enable us to diagnose recurrent disease early in the course. There have been few studies to evaluate the relation between neuropathic and the recurrence of cancer or survival. In another study, 73% of patients with head and neck cancer experienced neuropathic pain, and a linear trend was seen in the neuropathic component and nociceptive component [10]. Therefore, we assumed that persistent nociceptive caused by tumor or cancer treatment may be associated with the occurrence of NCP. In this study, it was found that NCP seemed to be indicative of recurrence. It is important for a physician to keep in mind that neuropathic cancer may be indicative of cancer recurrence and an appropriate evaluation for recurrent or metastatic disease should not be performed for early detection. Furthermore, well-designed prospective studies will be needed to validate the association between NCP and the recurrence of cancer.

Effects of β2 agonists on post-thoracotomy pain incidence.

Pre-clinical research has shown β2 -adrenoceptors to be essential for the antiallodynic action of antidepressant drugs in murine models of neuropathic pain and that sustained treatment with β2 -agonists has an antiallodynic action. Here, we clinically investigated whether chronic β2 -agonist treatments may influence the incidence of post-thoracotomy chronic pain, defined as pain that recurs or persists along a thoracotomy scar more than 2months after surgery, either neuropathic or non-neuropathic. We conducted an epidemiological study on patients operated by thoracotomy. Demographic data, medical history and treatments concomitant to the surgery were recorded at a follow-up visit. Information on perioperative treatments was collected from the anaesthesia records and confirmed by the patients. In patients with pain at the surgery level, post-thoracotomy chronic pain was assessed by clinical examination and numeric scale. Physical examination and DN4 questionnaire were used to discriminate neuropathic and non-neuropathic chronic pain at scar level. One hundred and eighty-nine patients were included. Eighty-one patients reported persisting thoracic pain, with neuropathic characteristics in 58 of them (30% of the 189 patients). The most common chronic drugs during the perioperative period were inhaled β2 -agonists (28.6%). The chronic use of β2 -agonists was an independent predictor of thoracic neuropathic pain (but not of non-neuropathic pain) and was associated with a five-fold decrease in the relative incidence of neuropathic pain [OR=0.19 (0.06-0.45)]. These data suggest a possible influence of chronic β2 -agonist treatments on neuropathic pain secondary to thoracotomy. This apparent preventive effect of β2 -agonist treatments should warrant controlled clinical trials.

Screening for neuropathic characteristics in failed back surgery syndromes: challenges for guiding treatment.

Neuropathic pain screening tools have shown promise in identifying common neuropathic pain characteristics that derive from diverse etiologies (e.g., diabetic peripheral neuropathy, postherpetic neuralgia). However, no prior studies have specifically assessed whether these tools are capable of discerning the underlying pain mechanisms in the vast, heterogeneous group of patients diagnosed with failed back surgery syndrome (FBSS). In this clinical observational study, two tests for neuropathic pain characteristics, the Douleur Neuropathique en 4 (DN4) and Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) questionnaires, were performed on 43 subjects with FBSS. Subjects underwent physical or neurosensory exam components of the DN4 and LANSS in the region of most severe pain (e.g., axial low back or lower extremities). DN4 and LANSS scores were correlated with clinical history and neurologic exam, pain-related quality of life questionnaires, and compared to an independent assessment of pain distribution. The presence of neuropathic characteristics, determined by the DN4 (62% sensitivity, 44% specificity), LANSS (38% sensitivity, 75% specificity; cut-offs of 4 and 12, respectively), or their combination (20% sensitivity, 58% specificity) was associated with higher pain intensity as measured by the visual analog scale (DN4 > 4, P = 0.001; LANSS ≥ 12, P = 0.042), modified Brief Pain Inventory-Short Form (DN4 > 4, P = 0.001; LANSS ≥ 12, P = 0.082), and Neuropathic Pain Symptom Inventory (DN4 > 4, P = 0.001; LANSS ≥ 12, P = 0.001), and greater pain-related functional impairment as measured by the Roland-Morris Disability Questionnaire (DN4 > 4, P = 0.006; LANSS ≥ 12, P = 0.018). The percentage of subjects characterized as neuropathic by the DN4 and LANSS lacked concordance (67.4 vs. 25.6), and the distribution of most severe symptoms (i.e., axial vs radicular) did not correlate with subjects determined to have neuropathic pain. Unlike other neuropathic syndromes, the neuropathic component of FBSS is less reliably identified by the LANSS and DN4.

Douleurs chroniques après chirurgie : état des lieux

Any type of surgery can lead to persistent pain (Chronic Post-Surgical Pain, CPSP), including minor or less invasive procedures. CPSP often but not always includes neuropathic pain features; when a neuropathic component is present, CPSP is more severe. The major risk factors for the development of CPSP are well known but not selective. New tools to target high-risk patients preoperatively are currently being assessed (e.g. the risk index from Althaus and colleagues) but remains not specific enough. Today, the prevention of CPSP might be improved by a better management of the patients, specifically by a better control of severe acute postoperative pain (i.e. early diagnosis of a neuropathic component involved, judicious utilization of peri-operative opioid analgesics, use of pain trajectories to better assess postoperative pain resolution).

Impact of pregabalin on the occurrence of postthoracotomy pain syndrome: a randomized trial.

Postthoracotomy pain syndrome (PTPS) is a frequent cause of chronic postoperative pain. Pregabalin might reduce the incidence of chronic postoperative pain. The goal of this study was to evaluate the impact of perioperative pregabalin on the occurrence of PTPS, defined as any surgical site pain 3 months after surgery. We conducted a randomized, placebo-controlled, double-blind trial in patients undergoing elective thoracotomy. Patients received either pregabalin 150 mg orally twice a day initiated 1 hour before thoracotomy and continued until 4 days after thoracotomy (10 doses total) or a placebo using the same protocol. All patients received preincision thoracic epidural analgesia. Postthoracotomy pain syndrome was evaluated using the Brief Pain Inventory questionnaire through a telephone interview. Secondary outcomes included evaluation of neuropathic characteristics through the Leeds Assessment of Neuropathic Symptoms and Signs questionnaire, analgesic use 3 months after surgery, and evaluation of acute postoperative pain and opioid consumption. One hundred fourteen patients were randomized, and 99 patients completed the study (placebo, n = 49; pregabalin, n = 50). Postthoracotomy pain syndrome occurred in 49 (49.5%) of 99 patients and more frequently in the pregabalin group (31/50 [62%] vs 18/49 [37%] in the placebo group, P = 0.01). However, among patients with PTPS, those in the pregabalin group required significantly less analgesics, reported less moderate to severe average pain, and presented significantly less neuropathic characteristics than patients in the placebo group 3 months after surgery. Pregabalin did not reduce the incidence of PTPS in this study. Future research on PTPS should focus on the impact of regional analgesia on central sensitization.

Neuropathic pain in patients with haemophilia, that is the question

Chronic pain caused by recurrent joint bleedings affects a large number of patients with haemophilia (PwH). The basis of this pain, nociceptive or neuropathic, has not been investigated so far. In other pain-related chronic disorders such as osteoarthritis or rheumatoid arthritis, initial studies showed nociceptive but also neuropathic pain features. 137 PwH and 33 controls (C) completed the painDETECT-questionnaire (pDq), which identifies neuropathic components in a person´s pain profile. Based on the pDq results, a neuropathic pain component is classified as positive, negative or unclear. A positive neuropathic pain component was found in nine PwH, but not in C. In 20 PwH an unclear pDq result was observed. In comparison to C the allocation of pDq results is statistically significant (p≤0.001). Despite various pDq results in PwH and C a similar appraisal pain quality, but on a different level, was determined. Summarising the results, there is a potential risk to misunderstand underlying pain mechanisms in PwH. In chronic pain conditions based on haemophilic arthopathy, a differential diagnosis seems to be unalterable for comprehensive and individualised pain management in PwH.