Neuropathic Features Research Articles

Effectiveness of Pulsed Radiofrequency with Multifunctional Epidural Electrode in Chronic Lumbosacral Radicular Pain with Neuropathic Features

Background: Lumbosacral radicular pain is a common clinical finding with a statistical prevalence ranging from 9.9% to 25% in the general population. Objective: To investigate the effectiveness of dorsal root ganglion pulsed radiofrequency (PRF) in patients with chronic lumbosacral radicular pain and neuropathic features. Study Design: Prospective case series clinical outcome study. Methods: We evaluated 34 patients with lumbosacral neuropathic pain who underwent PRF at the corresponding level of radicular symptoms distribution (ranging from L3 to S1). Each patient suffered a single leg-radiating pain with probable neuropathic features (assessed with clinical grading) lasting for > 6 months and unresponsive to previous treatments. A multifunctional PASHA-electrode® was introduced with trans-sacral access through a hollow needle, placed under fluoroscopic guidance into the lumbosacral epidural space and its active tip moved close to the dorsal root ganglion responsible of the clinical symptoms. After connecting the electrode to a generator, stimulation tests were performed and PRF was started and applied for 240 seconds at a frequency of 2Hz, amplitude of 45 V and a tip temperature between 40 – 42°C. If the pain involved more than a single nerve root, the electrode was placed at a different segment and the procedure repeated. Outcome measures included the pain intensity score on a 0 – 10 numeric rating scale (NRS) and the Italian Pain Questionnaire (QUID) at pre-treatment, one and 6 months post-treatment. P values < 0.05 were considered statistically significant. Results: In comparison with pre-treatment, a significant reduction in pain score was observed in mean NRS either at one and 6 months (P < 0.001). The QUID - Pain Rating Index rank displayed a parallel trend at the first (P < 0.001) and last follow-up (P = 0.01). Moreover, a direct correlation between the 2 scales occurred, showing a parallel score decreasing (P < 0.001). Eighteen (52.9%) and 17 (50%) of 34 patients showed pain reduction in NRS > 2 points and > 30%, at one and 6 months, respectively. Limitations: The non-controlled design of the study, the patients were heterogeneous, the small number of patients, and the duration of follow-up was limited to 6 months. Conclusions: PRF of dorsal root ganglion performed with a multifunctional electrode for > 240 seconds appears to be safe and might be more effective than the classic 120 seconds needlemediated approach. Therefore, it may be considered as a valuable tool for the treatment of lumbosacral radicular pain with neuropathic features. Key words: PRF, radicular pain, neuropathic pain, DRG, NRS, PRIr-T, multifunctional electrode

Phenotypic and molecular insights into spinal muscular atrophy due to mutations in BICD2.

Spinal muscular atrophy is a disorder of lower motor neurons, most commonly caused by recessive mutations in SMN1 on chromosome 5q. Cases without SMN1 mutations are subclassified according to phenotype. Spinal muscular atrophy, lower extremity-predominant, is characterized by lower limb muscle weakness and wasting, associated with reduced numbers of lumbar motor neurons and is caused by mutations in DYNC1H1, which encodes a microtubule motor protein in the dynein-dynactin complex and one of its cargo adaptors, BICD2. We have now identified 32 patients with BICD2 mutations from nine different families, providing detailed insights into the clinical phenotype and natural history of BICD2 disease. BICD2 spinal muscular atrophy, lower extremity predominant most commonly presents with delayed motor milestones and ankle contractures. Additional features at presentation include arthrogryposis and congenital dislocation of the hips. In all affected individuals, weakness and wasting is lower-limb predominant, and typically involves both proximal and distal muscle groups. There is no evidence of sensory nerve involvement. Upper motor neuron signs are a prominent feature in a subset of individuals, including one family with exclusively adult-onset upper motor neuron features, consistent with a diagnosis of hereditary spastic paraplegia. In all cohort members, lower motor neuron features were static or only slowly progressive, and the majority remained ambulant throughout life. Muscle MRI in six individuals showed a common pattern of muscle involvement with fat deposition in most thigh muscles, but sparing of the adductors and semitendinosus. Muscle pathology findings were highly variable and included pseudomyopathic features, neuropathic features, and minimal change. The six causative mutations, including one not previously reported, result in amino acid changes within all three coiled-coil domains of the BICD2 protein, and include a possible 'hot spot' mutation, p.Ser107Leu present in four families. We used the recently solved crystal structure of a highly conserved region of the Drosophila orthologue of BICD2 to further-explore how the p.Glu774Gly substitution inhibits the binding of BICD2 to Rab6. Overall, the features of BICD2 spinal muscular atrophy, lower extremity predominant are consistent with a pathological process that preferentially affects lumbar lower motor neurons, with or without additional upper motor neuron involvement. Defining the phenotypic features in this, the largest BICD2 disease cohort reported to date, will facilitate focused genetic testing and filtering of next generation sequencing-derived variants in cases with similar features.

Weight-Bearing Exercise and Foot Health in Native Americans.

Diabetes contributes to sensory peripheral neuropathy, which has been linked to lower limb abnormalities that raise the risk for foot ulcers and amputations. Because amputations are a reason for pain and hospitalization in those with diabetes, it is of critical importance to gain insight about prevention of ulcer development in this population. Although the American Diabetes Association (ADA) now recommends that individuals with neuropathy can engage in moderate-intensity weight-bearing activity (WBA), they must wear appropriate footwear and inspect their feet daily. The physical forces and inflammatory processes from WBA may contribute to plantar characteristics that lead to ulcers. The purpose of this study was to compare neuropathic status and foot characteristics in Native Americans according to WBA classification. The t tests for unequal sample sizes found that exercisers had more difficulty sensing baseline temperature than nonexercisers, except at the right foot (all p values < .05). By dividing groups into no/low risk and high risk for ulcer, a majority showed no/low risk according to touch and vibration sense. Exercisers demonstrated higher surface skin temperature gradients at the first metatarsal head, a plantar site where wounds tend to form. The more consistently exercisers performed, the higher the plan-tar pressures were at the right second (r = .24, p = .02) and third metatarsal heads (r = .26, p = .01). Findings from this investigation do not refute current ADA recommendations and further intervention studies are needed that are longitudinal and measures WBA more accurately.

BTBR ob/ob mice as a novel diabetic neuropathy model: Neurological characterization and gene expression analyses

Given the lack of treatments for diabetic neuropathy (DN), a common diabetic complication, accurate disease models are necessary. Characterization of the leptin-deficient BTBR ob/ob mouse, a type 2 diabetes model, demonstrated that the mice develop robust diabetes coincident with severe neuropathic features, including nerve conduction deficits and intraepidermal nerve fiber loss by 9 and 13weeks of age, respectively, supporting its use as a DN model. To gain insight into DN mechanisms, we performed microarray analysis on sciatic nerve from BTBR ob/ob mice, identifying 1503 and 642 differentially expressed genes associated with diabetes at 5 and 13weeks, respectively. Further analyses identified overrepresentation of inflammation and immune-related functions in BTBR ob/ob mice, which interestingly were more highly represented at 5weeks, an observation that may suggest a contributory role in DN onset. To complement the gene expression analysis, we demonstrated that protein levels of select cytokines were significantly upregulated at 13weeks in BTBR ob/ob mouse sciatic nerve. Furthermore, we compared our array data to that from an established DN model, the C57BKS db/db mouse, which reflected a common dysregulation of inflammatory and immune-related pathways. Together, our data demonstrate that BTBR ob/ob mice develop rapid and robust DN associated with dysregulated inflammation and immune-related processes.

Evaluation of Nerve Conduction Studies in Obese Children With Insulin Resistance or Impaired Glucose Tolerance.

The aim of the study was to investigate nerve conduction studies in terms of neuropathic characteristics in obese patients who were in prediabetes stage and also to determine the abnormal findings. The study included 69 obese adolescent patients between April 2009 and December 2010. All patients and control group underwent motor (median, ulnar, tibial, and peroneal) and sensory (median, ulnar, sural, and medial plantar) nerve conduction studies and sympathetic skin response test. Sensory response amplitude of the medial plantar nerve was significantly lower in the patients with impaired glucose tolerance and insulin resistance. To our knowledge, the present study is the first study demonstrating the development of sensory and autonomic neuropathy due to metabolic complications of obesity in adolescent children even in the period without development of diabetes mellitus. We recommend that routine electrophysiological examinations be performed, using medial plantar nerve conduction studies and sympathetic skin response test.

Chronic pain 1 year after foot surgery: Epidemiology and associated factors

BackgroundMost studies of chronic postoperative pain focussed on major surgical procedures. Chronic postoperative pain occurred in 10% to 50% of patients and exhibited neuropathic features in 5% to 68% of cases. The objectives of this prospective single-centre study were to determine the rates of occurrence and associated factors of any chronic pain and of neuropathic chronic pain 1year after orthopaedic surgery on the foot. MethodsWe included consecutive patients who underwent scheduled orthopaedic surgery on the foot or ankle at a university hospital centre between 2009 and 2011. All patients received a multimodal analgesia regimen that usually combined a continuous popliteal sciatic nerve block, paracetamol, and ketoprofen, with additional ketamine if deemed appropriate. A telephone interview was conducted 1year after the surgical procedure. The main outcome measures were moderate-to-severe pain (numerical rating scale score>3/10) 1year after surgery at rest and during walking, and presence of neuropathic pain (defined using the DN2 score). Multivariate analysis was performed to look for associations of various perioperative clinical variables with pain. ResultsOne year after surgery, 55 of 260 (21%) patients reported moderate-to-severe pain at rest, 111 (43%) moderate-to-severe pain during walking, and 9 (3%) neuropathic pain. By multivariate analysis, factors independently associated with moderate-to-severe pain at rest and/or during walking 1year after surgery were moderate-to-severe pain during the first postoperative night (P=0.048) and/or day (P=0.043) and revision surgery (P=0.001). DiscussionThe rate of occurrence of moderate-to-severe pain 1year after orthopaedic foot surgery is similar to that seen after major surgical procedures, whereas neuropathic pain seems rare. Orthopaedic surgery on the ankle or hindfoot is not more likely to be followed by chronic pain compared to surgery for hallux valgus or toe abnormalities. There is some evidence that earlier surgery might be beneficial. Level of evidenceIV, prospective observational longitudinal cohort study.

Neuropathic Pain Features in Patients With Bone Metastases

Neuropathic Pain Features in Patients With Bone Metastases

Thoracic sympathetic block for the treatment of complex regional pain syndrome type I: A double-blind randomized controlled study

Pain relief in complex regional pain syndrome (CRPS) remains a major challenge, in part due to the lack of evidence-based treatment trials specific for this condition. We performed a long-term randomized, double-blinded active-control study to evaluate the efficacy of thoracic sympathetic block (TSB) for upper limb type I CRPS. The study objective was to evaluate the analgesic effect of TSB in CRPS. Patients with CRPS type I were treated with standardized pharmacological and physical therapy and were randomized to either TSB or control procedure as an add-on treatment. Clinical data, pain intensity, and interference (Brief Pain Inventory), pain dimensions (McGill Pain Questionnaire [MPQ]), neuropathic characteristics (Neuropathic Pain Symptom Inventory [NPSI]), mood, upper limb function (Disabilities of Arm, Shoulder and Hand), and quality of life were assessed before, and at 1 month and 12 months after the procedure. Thirty-six patients (19 female, 44.7±11.1 years of age) underwent the procedure (17 in the TSB group). Average pain intensity at 1 month was not significantly different after TSB (3.5±3.2) compared to control procedure (4.8±2.7; P=0.249). At 12 months, however, the average pain item was significantly lower in the TSB group (3.47±3.5) compared to the control group (5.86±2.9; P=0.046). Scores from the MPQ, evoked-pain symptoms subscores (NPSI), and depression scores (Hospital Anxiety and Depression Scale) were significantly lower in the TSB group compared to the control group at 1 and at 12 months. Other measurements were not influenced by the treatment. Quality of life was only slightly improved by TSB. No major adverse events occurred. Larger, multicentric trials should be performed to confirm these original findings.

Deletion of KCC3 in parvalbumin neurons leads to locomotor deficit in a conditional mouse model of peripheral neuropathy associated with agenesis of the corpus callosum

Hereditary motor and sensory neuropathy associated with agenesis of the corpus callosum (HMSN/ACC or ACCPN) is an autosomal recessive disease caused by the disruption of the SLC12A6 gene, which encodes the K–Cl cotransporter-3 (KCC3). A ubiquitous deletion of KCC3 in mice leads to severe locomotor deficits similar to ACCPN patients. However, the underlying pathological mechanism leading to the disease remains unclear. Even though a recent study suggests that the neuropathic features of ACCPN are mostly due to neuronal loss of KCC3, the specific cell type responsible for the disease is still unknown. Here we established four tissue specific KCC3 knockout mouse lines to explore the cell population origin of ACCPN. Our results showed that the loss of KCC3 in parvalbumin-positive neurons led to significant locomotor deficit, suggesting a crucial role of these neurons in the development of the locomotor deficit. Interestingly, mice in which KCC3 deletion was driven by the neuron-specific enolase (NSE) did not develop any phenotype. Furthermore, we demonstrated that nociceptive neurons targeted with Nav1.8-driven CRE and Schwann cells targeted with a desert hedgehog-driven CRE were not involved in the development of ACCPN. Together, these results establish that the parvalbumin-positive neuronal population is an important player in the pathogenic development of ACCPN.

Estimating the burden of disease in chronic pain with and without neuropathic characteristics: Does the choice between the EQ-5D and SF-6D matter?

The EQ-5D and Short Form (SF)12 are widely used generic health-related quality of life (HRQoL) questionnaires. They can be used to derive health utility index scores, on a scale where 0 is equivalent to death and 1 represents full health, with scores less than zero representing states “worse than death.” We compared EQ-5D or SF-6D health utility index scores in patients with no chronic pain, and chronic pain with and without neuropathic characteristics (NC), and to explore their discriminant ability for pain severity. Self-reported health and chronic pain status was collected as part of a UK general population survey (n=4451). We found moderate agreement between individual dimensions of EQ-5D and SF-6D, with most highly correlated dimensions found for mental health and anxiety/depression, role limitations and usual activities, and pain and pain/discomfort. Overall 43% reported full health on the EQ-5D, compared with only 4.2% on the SF-6D. There were significant differences in mean utilities for chronic pain with NC (EQ-5D 0.47 vs SF-6D 0.62) and especially for severe pain (EQ-5D 0.33 vs SF-6D 0.58). On the EQ-5D, 17% of those with chronic pain with NC and 3% without NC scored “worse than death,” a state which is not possible using the SF-6D. Health utilities derived from EQ-5D and SF-12/36 can discriminate between group differences for chronic pain with and without NC and greater pain severity. However, the instruments generate widely differing HRQoL scores for the same patient groups. The choice between using the EQ-5D or SF-6D matters greatly when estimating the burden of disease.

Voxel-based morphometry and arterial spin labeling fMRI reveal neuropathic and neuroplastic features of brain processing of itch in end-stage renal disease

Pruritus of end-stage renal disease (ESRD) is a multifactorial symptom of complex etiology not yet fully understood. In this study we have investigated the cerebral perfusion patterns at rest in ESRD patients on hemodialysis, compared with those in healthy volunteers. We have also studied the brain responses evoked by experimental itch induction in ESRD, after stimulating the two distinct histamine and cowhage itch pathways, and compared them with the responses evoked in healthy volunteers. To identify potential structural alterations in ESRD patients compared with a group of age-matched healthy volunteers, we calculated the density of gray matter for the entire brain using a voxel-based morphometric analysis. Our results indicated that gray matter density was significantly reduced in ESRD patients in the frontal, parietal, temporal, and occipital cortices, as well as in the S1, precuneus, and insula, whereas the brain stem, hippocampus, amygdala, midcingulate cortex, and nucleus accumbens displayed an increased gray matter density. Functionally, we found a significantly higher brain perfusion at baseline associated with ESRD pruritus in the anterior cingulate, insula, claustrum, hippocampus, and nucleus accumbens. The brain responses evoked by cowhage itch, which are mediated by protease-activated receptors (PAR2), displayed significant differences compared with responses in healthy individuals and were correlated with perceived itch intensity in a dual, complex manner. The inverse correlations in particular suggested that a negative feedback mechanism modulated itch intensity, when elicited in a preexistent chronic itch background.

Efficacy and safety of ultrasound-guided saphenous nerve block in patients with chronic knee pain

IntroductionKnee osteoarthritis is a common cause for consultation around the world. Many patients with mild symptoms respond to conservative treatment, while others require interventional therapy including peripheral nerve blocks. ObjectiveTo establish the clinical efficacy and safety of interventional management with ultrasound-guided saphenous nerve block in patients with chronic keen pain. Materials and methodsDescriptive, retrospective trial in chronic keen pain patients who underwent ultrasound-guided interventional therapy at the pain clinic in the country, between September 2011 and June 2012, to determine the clinical efficacy and safety of the procedure. Data were obtained from all patients prior to the procedure, and then at two days, one month and three months later. The pain intensity was measured using the visual analog scale. Results25 saphenous nerve blocks were performed. 68% of the patients experienced pain relief within two days. 56% and 40% exhibited relief one and three months after the procedure, respectively, with a statistically significant difference (p<0.0001) between the baseline visual analog scale and the follow-up evaluation. Patients with a history of fibromyalgia, neuropathic characteristics and previous knee surgery exhibited variable analgesic responses to the procedure. ConclusionsInterventionist chronic knee pain management with ultrasound-guided saphenous nerve block was an effective and safe approach for these patients.

Eficacia y seguridad del bloqueo del nervio safeno guiado por ultrasonido en pacientes con dolor crónico de rodilla

IntroductionKnee osteoarthritis is a common cause for consultation around the world. Many patients with mild symptoms respond to conservative treatment, while others require interventional therapy including peripheral nerve blocks. ObjectiveTo establish the clinical efficacy and safety of interventional management with ultrasound-guided saphenous nerve block in patients with chronic keen pain. Materials and methodsDescriptive, retrospective trial in chronic keen pain patients who underwent ultrasound-guided interventional therapy at the pain clinic in the country, between September 2011 and June 2012, to determine the clinical efficacy and safety of the procedure. Data were obtained from all patients prior to the procedure, and then at two days, one month and three months later. The pain intensity was measured using the visual analog scale. Results25 saphenous nerve blocks were performed. 68% of the patients experienced pain relief within two days. 56% and 40% exhibited relief one and three months after the procedure, respectively, with a statistically significant difference (p < 0.0001) between the baseline visual analog scale and the follow-up evaluation. Patients with a history of fibromyalgia, neuropathic characteristics and previous knee surgery exhibited variable analgesic responses to the procedure. ConclusionsInterventionist chronic knee pain management with ultrasound-guided saphenous nerve block was an effective and safe approach for these patients.

High Prevalence of Neuropathic Pain Features in Patients with Knee Osteoarthritis: A Cross-Sectional Study.

The present epidemiological research evaluated the prevalence of neuropathic pain characteristics in patients with painful knee osteoarthritis (OA) and the plausibility that such neuropathic features were specific of OA. Outpatients with chronic pain associated with knee OA who attended orthopedic surgery or rehabilitation clinics were systematically screened for neuropathic pain with the Douleur Neuropathique in 4 questions (DN4) questionnaire. Data from medical files and those obtained during a single structured clinical interview were correlated with the DN4 scores. Information on potential confounders of neuropathic-like qualities of knee pain was collected to evaluate as much as possible only the symptoms attributable to OA. Of 2,776 patients recruited, 2,167 patients provided valid data from 2,992 knees. The DN4 was scored positively (≥ 4) in 1,125 patients (51.9%) and 1,459 knees (48.8%). When patients with potential confounders were excluded, the respective prevalences were 33.3% and 29.4%. Patients who scored positively in the DN4 had more severe pain, greater structural damage, and more potential confounders of neuropathic pain. Three potential confounders conveyed much of the variability explained by regression analyses. However, latent class analyses revealed that the concourse of other factors is required to explain the neuropathic pain qualities. A relevant proportion of patients with chronic pain associated with knee OA featured neuropathic pain qualities that were not explained by other conditions. The present research has provided reasonable epidemiological grounds to attempt their definite diagnosis and classification.

Osteoarthritis pain: nociceptive or neuropathic?

In this article, we present the case for the existence of a subgroup of patients with osteoarthritis (OA) who experience pain with neuropathic features. Recognizing these patients as a distinct subgroup will allow clinicians to improve the management of their symptoms. We discuss the diagnostic criteria for pain to be classed as neuropathic, then systematically examine the applicability of these criteria to the symptoms, signs and pathology of OA. What are the implications for the preclinical development and clinical use of analgesics for OA? How should existing treatment options be reassessed? Differences in the aetiology of OA and the pharmacological sensitivity of patients with OA pain with neuropathic features, compared with other patients with OA, might explain the frequent negative findings of clinical trials of treatments for symptomatic OA. If the global prevalence of OA pain with neuropathic features is accurately represented by reports from small experimental groups of patients, then a substantial unmet need to tailor diagnosis and therapy for these individuals exists.

Chronic pain in type 2 diabetic patients: A cross-sectional study in primary care setting

Background: Although diabetes mellitus (DM) is often associated with painful neuropathic syndromes, a significant number of DM patients suffer from non-neuropathic (nociceptive) pain. Unfortunately, there is insufficient data on the epidemiology of nociceptive pain in DM patients and its effect on their quality of life.Objective: To characterize pain in type 2 DM patients, and assess its effect on their quality of life.Methods: The study population included 342 type 2 DM patients, 18 years of age and above (mean age 70.7 ± 9.7), who reported having pain. The study questionnaires included the Brief Pain Inventory (BPI), the S-LANSS scale to assess pain with neuropathic features, life impact, and socio-demographic data.Results: One hundred and fifty-five DM patients (46.5%) reported having pain of predominantly neuropathic origin. Almost 75% of patients with neuropathic pain were females, compared to 57.8% of patients with nociceptive pain (P = 0.002). More patients with neuropathic pain reported constant daily pain (57.6% vs. 42.4%, P < 0.0001), and worse pain during the night (53.3% vs. 46.7%, P = 0.045). The pain affected daily activities, walking capacity, and mood. Patients with neuropathic pain reported a greater negative effect of pain on their quality of life than those with nociceptive pain (41.0% vs. 15.3%, P < 0.0001).Conclusion: The impact of neuropathic pain in DM patients is much more significant than nociceptive pain and affects their quality of life and daily function to a greater degree.

Molecular, clinical and peripheral neuropathy study of Tunisian patients with ataxia with vitamin E deficiency

Ataxia with vitamin E deficiency is an autosomal recessive cerebellar ataxia caused by mutations in the α-tocopherol transfer protein coding gene localized on chromosome 8q, leading to lower levels of serum vitamin E. More than 91 patients diagnosed with ataxia with vitamin E deficiency have been reported worldwide. The majority of cases originated in the Mediterranean region, and the 744delA was the most common mutation among the 22 mutants previously described. We examined the clinical and molecular features of a large cohort of 132 Tunisian patients affected with ataxia with vitamin E deficiency. Of these patients, nerve conduction studies were performed on 45, and nerve biopsy was performed on 13. Serum vitamin E was dramatically reduced for 105 of the patients analysed. Molecular analysis revealed that 91.7% of the patients (n = 121) were homozygous for the 744delA mutation. Three other mutations were detected among the remaining patients (8.3%, n = 11) in the homozygous state. Two were previously reported (400C>T and 205-1G>T), and one was novel (553+1T>A). Age of onset was 13.2 ± 5.9 years, with extremes of 2 and 37 years. All described patients exhibited persistent progressive cerebellar ataxia with generally absent tendon reflexes. Deep sensory disturbances, pyramidal syndrome and skeletal deformities were frequent. Head tremor was present in 40% of the patients. Absence of neuropathy or mild peripheral neuropathy was noted in more than half of the cohort. This is the largest study of the genetic, clinical and peripheral neuropathic characteristics in patients with ataxia and vitamin E deficiency. The 744delA mutation represents the most common pathological mutation in Tunisia and worldwide, likely because of a Mediterranean founder effect. Our study led us to suggest that any patient displaying an autosomal recessive cerebellar ataxia phenotype with absent tendon reflexes and minor nerve abnormalities should first be screened for the 744delA mutation, even in the absence of a serum vitamin E measurement.

Neuropathic characteristics of pain in osteoarthritis of the knee in Spain: ENDARE study

Neuropathic characteristics of pain in osteoarthritis of the knee in Spain: ENDARE study

Neuropathic Aspects of Persistent Postsurgical Pain: A French Multicenter Survey With a 6-Month Prospective Follow-Up

To investigate the role of peripheral neuropathy in the development of neuropathic postsurgical persistent pain (N-PSPP) after surgery, this French multicentric prospective cohort study recruited 3,112 patients prior to elective cesarean, inguinal herniorrhaphy (open mesh/laparoscopic), breast cancer surgery, cholecystectomy, saphenectomy, sternotomy, thoracotomy, or knee arthroscopy. Besides perioperative data collection, postoperative postal questionnaires built to assess the existence, intensity, and neuropathic features (with the Douleur Neuropathique 4 Questions [DN4]) of pain at the site of surgery were sent at the third and sixth months after surgery. In the 2,397 patients who completed follow-up, the cumulative risk of N-PSPP within the 6 months ranged from 3.2% (laparoscopic herniorrhaphy) to 37.1% (breast cancer surgery). Pain intensity was greater if DN4 was positive and decreased with time since surgery; it depended on the type of surgery. In pain-reporting patients, the response to the DN4 changed from time to time in about 1:4 of the cases. Older age and a low anxiety score were independent protective factors of N-PSPP, whereas a recent negative event, a low preoperative quality of life, and previous history of peripheral neuropathy were risk factors. The type of anesthesia had no influence on the occurrence of N-PSPP. Trial registration: ClinicalTrials.gov, NCT00812734. PerspectiveThis prospective observational study provides the incidence rate of N-PSPP occurring within the 6 months after 9 types of elective surgical procedures. It highlights the possible consequences of nerve aggression during some common surgeries. Finally, some preoperative predispositions to the development of N-PSPP have been identified.

Neuropathy, neuropathic pain, and sickle cell disease

Neuropathy, neuropathic pain, and sickle cell disease