When does acute pain become chronic?

N-Pyrazoloyl and N-thiopheneacetyl hydrazone of isatin exhibited potent anti-inflammatory and anti-nociceptive properties through suppression of NF-κB, MAPK and oxidative stress signaling in animal models of inflammation

BACKGROUND

Hydrazide derivatives constitute an important class of compounds for new drug development as they are reported to possess good anti-inflammatory and analgesic activity. The present study was aimed to investigate the role of newly synthesized hydrazide derivatives N-pyrazoloyl hydrazone of isatin (PHI) and N-thiopheneacetyl hydrazone of isatin (THI) in acute and chronic inflammatory pain models induced by carrageenan and complete Freud's adjuvant (CFA).

MATERIALS

PHI and THI (0.1, 1 and 10 mg/kg) pretreatments were provided intraperitoneally to male BALB/c mice prior to inflammatory inducers. Behavioral responses to inflammation and pain were evaluated by assessment of paw edema, mechanical allodynia, mechanical and thermal hyperalgesia. Cytokines production and NF-κB levels were evaluated by ELISA. Western blot analysis was performed for the detection of IκBα, p38, JNK and ERK. Hematoxylin and eosin (H&E) staining and radiographic analysis were performed to evaluate the effect of PHI and THI treatment on bone and soft tissues. Oxidative stress was determined by reduced glutathione, glutathione-S-transferase and catalase assays. Evans blue dye was used to monitor vascular protein leakage.

RESULT

PHI and THI dose dependently (0.1, 1 and 10 mg/kg) reduced inflammation and pain in mice, however, the dose of 10 mg/kg exhibited significant activity. The anti-inflammatory and analgesic effects were attributed to suppression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) production levels. PHI and THI significantly blocked CFA-induced activation of NF-κB and MAPK signaling pathways. Oxidative stress and plasma nitrite levels were reduced remarkably. The PHI and THI (10 mg/kg) treatment did not exhibit any apparent toxicity on the liver, kidney, muscles strength, and motor co-ordination in mice.

CONCLUSION

Both PHI and THI possess significant anti-inflammatory and analgesic activity via inhibition of inflammatory mediators.

Revisiting Tramadol: A Multi-Modal Agent for Pain Management

Tramadol-an atypical opioid analgesic-has a unique pharmacokinetic and pharmacodynamic profile, with opioidergic, noradrenergic, and serotonergic actions. Tramadol has long been used as a well-tolerated alternative to other drugs in moderate pain because of its opioidergic and monoaminergic activities. However, cumulative evidence has been gathered over the last few years that supports other likely mechanisms and uses of tramadol in pain management. Tramadol has modulatory effects on several mediators involved in pain signaling, such as voltage-gated sodium ion channels, transient receptor potential V1 channels, glutamate receptors, α₂-adrenoceptors, adenosine receptors, and mechanisms involving substance P, calcitonin gene-related peptide, prostaglandin E₂, and proinflammatory cytokines. Tramadol also modifies the crosstalk between neuronal and non-neuronal cells in peripheral and central sites. Through these molecular effects, tramadol could modulate peripheral and central neuronal hyperexcitability. Given the broad spectrum of molecular targets, tramadol as a unimodal analgesic relieves a broad range of pain types, such as postoperative, low back, and neuropathic pain and that associated with labor, osteoarthritis, fibromyalgia, and cancer. Moreover, tramadol has anxiolytic, antidepressant, and anti-shivering activities that could improve pain management outcomes. The aim of this review was to address these issues in the context of maladaptive physiological and psychological processes that are associated with different pain types.

Pain Management in the Cancer Survivor

OBJECTIVES

To describe assessment and interdisciplinary management of pain in the cancer survivor over the continuum of cancer care.

DATA SOURCES

Review of the literature and treatment standards.

CONCLUSION

Pain remains a primary concern throughout the cancer trajectory across all age groups and diagnoses, emphasizing the need to integrate pain assessment and management across the continuum of cancer survivorship and across care settings. Types of pain, pain patterns, assessment of cancer pain in cancer survivors, current strategies and challenges for management, and effective communication and documentation of the process are described. Communication between and among health care clinicians in a way that effectively articulates the individual patient experience, including documentation in the electronic medical record, requires consistent workflows and terminology. The opioid crisis increases the urgency in effective strategies for interdisciplinary pain assessment and management.

IMPLICATIONS FOR NURSING PRACTICE

Oncology clinicians must be able to adequately assess pain, track pain over time, understand and implement a cadre of strategies to manage pain, and effectively pursue any suspicious pain patterns that may indicate recurrence or progression of cancer or other underlying etiologies. The oncology nurse is at the core of patient-clinician communication, critical to effectively describing pain as experienced by the individual patient and continues to play a key role in maintaining consistency of message that is necessary to manage pain over the continuum of cancer survivorship.

Molecular expression patterns in the synovium and their association with advanced symptomatic knee osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a major source of knee pain. Mechanisms of OA knee pain are incompletely understood but include synovial pathology. We aimed to identify molecular expression patterns in the synovium associated with symptomatic knee OA.

DESIGN

Snap frozen synovia were from people undergoing total knee replacement (TKR) for advanced OA, or from post-mortem (PM) cases who had not sought help for knee pain. Associations with OA symptoms were determined using discovery and validation samples, each comprising TKR and post mortem (PM) cases matched for chondropathy (Symptomatic or Asymptomatic Chondropathy). Associations with OA were determined by comparing age matched TKR and PM control cases. Real-time quantitative PCR for 96 genes involved in inflammation and nerve sensitisation used TaqMan^® Array Cards in discovery and validation samples, and protein expression for replicated genes was quantified using Luminex bead assay.

RESULTS

Eight genes were differentially expressed between asymptomatic and symptomatic chondropathy cases and replicated between discovery and validation samples (P<0.05 or >3-fold change). Of these, matrix metalloprotease (MMP)-1 was also increased whereas interleukin-1 receptor 1 (IL1R1) and vascular endothelial growth factor (VEGF) were decreased at the protein level in the synovium of symptomatic compared to asymptomatic chondropathy cases. MMP1 protein expression was also increased in OA compared to PM controls.

CONCLUSION

Associations of symptomatic OA may suggest roles of MMP1 expression and IL1R1 and VEGF pathways in OA pain. Better understanding of which inflammation-associated molecules mediate OA pain should inform refinement of existing therapies and development of new treatments.

Salvia mellifera-How Does It Alleviate Chronic Pain?

Black sage, Salvia mellifera, can be made into a sun tea that is used as a foot soak to treat pain patients. The monoterpenoids and diterpenoids in the preparation penetrate the skin of the feet and stop the pain chemokine cycle, which may be the basis of chronic pain. Several chronic pain patients have reported long-term improvements in their pain after treatment with the preparation.

Acute Pain Is Associated With Chronic Opioid Use After Total Knee Arthroplasty

BACKGROUND AND OBJECTIVES

Pain scores are routinely reported in clinical practice, and we wanted to examine whether this routinely measured, patient-reported variable provides prognostic information, especially with regard to chronic opioid use, after taking preoperative and perioperative variables into account in a preoperative opioid user population.

METHODS

In 32,874 preoperative opioid users undergoing primary total knee arthroplasty at Veterans Affairs hospitals between 2010 and 2015, we compared preoperative and perioperative characteristics in patients reporting lower versus higher acute pain (scores ≤4/10 vs >4/10 averaged over days 1-3). We calculated the propensity for lower acute pain based on all available data. After 1:1 propensity score matching, to identify similar patients differing only in acute pain, we contrasted rates of chronic significant opioid use (mean >30 mg/d in morphine equivalents) beyond postoperative month 3, discharge prescriptions, and changes in postoperative versus preoperative dose categories. Sensitivity analysis examined associations with dose escalation.

RESULTS

Rates of chronic significant opioid use (21% overall) differed in patients with lower versus higher acute pain (36% vs 64% of the overall cohort). After propensity matching (total n = 20,926 patients) and adjusting for all significant factors, lower acute pain was associated with less chronic significant opioid use (rates 12% vs 16%), smaller discharge prescriptions (ie, supply <30 days and daily oral morphine equivalent <30 mg/d), and more reduction in dose, all P < 0.001. In sensitivity analysis, dose escalation was 15% less likely with lower acute pain (odds ratio, 0.85; 95% confidence interval, 0.80-0.91).

CONCLUSIONS

Acute pain predicts chronic opioid use. Prospective studies of efforts to reduce acute pain, in terms of long-term effects, are needed.

A randomized controlled trial of postoperative intravenous acetaminophen plus thoracic epidural analgesia vs. thoracic epidural analgesia alone after gastrectomy for gastric cancer

BACKGROUND

Acetaminophen is used in multimodal therapy for postoperative pain management. However, the additional effects of acetaminophen in combination with thoracic epidural analgesia (TEA) are not well understood. This prospective, multicenter randomized study was conducted to evaluate the efficacy of routine intravenous (i.v.) acetaminophen in combination with TEA for the management of postoperative pain in gastric cancer surgery.

METHODS

A total of 120 patients who underwent distal gastrectomy were randomly assigned in a 1:1 ratio to receive i.v. acetaminophen every 6 h and TEA during the first 3 postoperative days (acetaminophen group) or TEA alone (control group). The primary endpoint was the sum of TEA rescue doses during the first 2 postoperative days.

RESULTS

Final analysis included 58 patients in the acetaminophen group and 56 patients in the control group. The median number of TEA rescue doses was significantly lower in the acetaminophen group compared with the control group (3.0 vs. 8.0, p = 0.013). The median area under the curve (AUC) of the pain scores at coughing was significantly less in the acetaminophen group compared with the control group (285 vs. 342, p = 0.046) without an increase in postoperative complications. TEA rescue doses and pain score AUCs were significantly reduced by acetaminophen in patients who underwent open gastrectomy (p = 0.037 and 0.045), whereas there was no significant difference between patients who underwent laparoscopic gastrectomy in the two groups.

CONCLUSIONS

In gastric cancer surgery patients, routine i.v. acetaminophen in combination with TEA provides superior postoperative pain management compared with TEA alone.

The clinical utility of repetitive transcranial magnetic stimulation in reducing the risks of transitioning from acute to chronic pain in traumatically injured patients

Pain is a multifaceted condition and a major ongoing challenge for healthcare professionals having to treat patients in whom pain put them at risk of developing other conditions. Significant efforts have been invested in both clinical and research settings in an attempt to demystify the mechanisms at stake and develop optimal treatments as well as to reduce individual and societal costs. It is now universally accepted that neuroinflammation and central sensitization are two key underlying factors causing pain chronification as they result from maladaptive central nervous system plasticity. Recent research has shown that the mechanisms of action of repetitive transcranial magnetic stimulation (rTMS) make it a particularly promising avenue in treating various pain conditions. This review will first discuss the contribution of neuroinflammation and central sensitization in the transition from acute to chronic pain in traumatically injured patients. A detailed discussion on how rTMS may allow the restoration from maladaptive plasticity in addition to breaking down the chain of events leading to pain chronification will follow. Lastly, this review will provide a theoretical framework of what might constitute optimal rTMS modalities in dealing with pain symptoms in traumatically injured patients based on an integrated perspective of the physiopathological mechanisms underlying pain.

Central sensitization is a risk factor for wound complications after primary total knee arthroplasty

PURPOSE

Postoperative wound complication is a significant risk factor for subsequent deep periprosthetic joint infection after total knee arthroplasty (TKA). Central sensitization is an abnormal enhancement of pain mechanism involving the central nervous system. Although psychological disorder is widely considered as a risk factor, the relationship between central sensitization and wound complication is currently unclear. Therefore, the purpose of this study was to investigate whether central sensitization was associated with high wound complication rate after primary TKA.

MATERIALS AND METHODS

Between January and June 2016, 161 patients undergoing unilateral TKA were prospectively divided into two groups based on central sensitization inventory score of 40 points after excluding cases with known risk factors such as physical comorbidities, health-related behaviors, and psychological disorders. Group 1 consisted of 112 patients (112 knees) whose central sensitization inventory score was < 40 points and group 2 consisted of 49 patients (49 knees) whose central sensitization inventory score was ≥ 40 points. Wound complications were defined as wound dehiscence, suture granuloma, prolonged wound oozing after postoperative day 5, significant hematoma formation, or surgical site infection recorded during the initial 90-day postoperative period. Demographic data, visual analog scale (VAS), central sensitization inventory score, and wound complications were compared between the two groups.

RESULTS

Wound complications developed in 3 (2.7%) knees in group 1 and 14 (28.6%) knees in group 2 (p < 0.001). Multivariate logistic regression analysis showed that the odds of postoperative wound complications were increased 15.7 times in patients with central sensitization inventory score ≥ 40 (95% CI 4.1-60.0, p < 0.001).

CONCLUSION

Central sensitization is a risk factor for the development of postoperative wound complication after primary TKA.

LEVEL OF EVIDENCE

II.

C-reactive Protein Level on Postoperative Day One is Associated with Chronic Postsurgical Pain After Mastectomy

Background

C-reactive protein (CRP) is an acute phase reactant released in response to inflammation or tissue injury. Inflammation is one of the pathogenic factors related to transition from acute postsurgical pain (APSP) to chronic postsurgical pain (CPSP). Although several risk factors are reportedly associated with CPSP, the effects of CRP levels on CPSP have not been examined.

Objectives

The present study investigated the relationship between perioperative risk factors, including CRP levels on postoperative day one and CPSP, in patients undergoing mastectomy.

Methods

Preoperative anxiety and depression levels were evaluated in female patients undergoing mastectomy under general anesthesia, with or without peripheral nerve block. Patients with chronic preoperative pain and/or preoperative breast pain were excluded. The intensity of postoperative pain was prospectively examined one and six days, and three and twelve months after surgery using a numerical rating scale (NRS).

Results

The current researchers conducted univariate and multivariate linear regression analyses to explore risk factors for CPSP in 36 patients. Patient demographics, preoperative psychological states, and anesthetic managements showed no relationship with CPSP. On the other hand, pain intensity of APSP and CRP levels on postoperative day one was significantly associated with the pain intensity of CPSP.

Conclusions

Postoperative CRP level is likely to be associated with the development of CPSP after mastectomy.

Mechanical/thermal sensitivity and superficial temperature in the stump of long-term tail-docked dairy cows

Background

Tail docking of dairy cows is a painful procedure that affects animal welfare level. The aims of this study were first to evaluate the response to mechanical and thermal stimulation, and second to determine the superficial temperature of the stump of tail-docked dairy cows.

Methods

One hundred and sixty-four dairy cows were enrolled. From these, 133 cows were assigned to the tail-docked (TD) group and 31 cows were selected as control animals. The following sensory assessments to evaluate pain in tail-docked cows were performed. Sensitivity of the tail region in both groups of animals was evaluated using a portable algometer. Cold and heat sensitivity assessment was performed using a frozen pack (0 °C) and warm water (45 °C), respectively. Pinprick sensitivity was evaluated using a Wartenberg neurological pinwheel. Superficial temperature was evaluated using a thermographic camera. All sensory assessments and superficial temperature were evaluated in the ventral surface of the tail stump (TD) and tail (C).

Results

Pressure pain threshold was lower in TD cows (5.97 ± 0.19 kg) compared to control cows (11.75 ± 0.43 kg). Heat and cold sensitivity was higher in the TD cows compared to control cows with 29% and 23% of TD cows responding positively, respectively. Similarly, after pinprick sensitivity test was performed, 93% of TD cows elicited a positive response to stimulation. Tail-docked cows had lower superficial temperature (26.4 ± 0.27 °C) compared to control cows (29.9 ± 0.62 °C).

Discussion

Pressure pain threshold values in both groups of animals were higher than those previously reported for TD pigs, sows and cows. In contrast, pinprick stimulation evaluates the presence of punctate mechanical hyperalgesia/allodynia, usually related to traumatic nerve injury, and this association may reveal that it is possible that these animals developed a disorder associated to the development of a tail stump neuroma and concurrent neuropathic pain, previously reported in TD lambs, pigs and dogs. Thermal sensitivity showed that TD cows responded positively to heat and cold stimulation. These findings suggest that long-term TD cows could be suffering hyperalgesia/allodynia, which may be indicative of chronic pain. Lower superficial temperature in the stump may be associated to sympathetic fiber sprouting in the distal stump, which can lead to vasoconstriction and lower surface temperatures. Further studies are needed in order to confirm neuroma development and adrenergic sprouting.

Perioperative factors associated with persistent opioid use after extensive abdominal surgery in children and adolescents: A retrospective cohort study

BACKGROUND

In adults, preoperative opioid use and higher perioperative opioid consumption have been associated with higher odds of persistent opioid use after surgery. There are limited data on the prevalence and factors associated with persistent opioid use after major oncologic surgery in children.

AIMS

In this study, we sought to determine the prevalence and factors associated with the development of persistent opioid use in a group of children and adolescents who had undergone cytoreductive surgery with hyperthermic intraperitoneal chemotherapy.

METHODS

A retrospective study of patients ≤19 years of age was performed. Univariable logistic regression was used to assess factors associated with a postdischarge persistent opioid use of up to 6 months.

RESULTS

Eighty-six children were identified. The median age was 12 years, and 43% were female. The proportion of patients with persistent opioid use over the immediate 3, 6, 12 and 24 postdischarge months was 54/77 (70%), 18/51 (35%), 13/45 (29%), and 3/24 (13%), respectively. The daily average in-patient pain scores were higher in the group of children who subsequently developed persistent opioid use of up to 6 months (estimated difference 0.5, 95% confidence interval [CI]: 0.3, 0.8, P < .01). Furthermore, higher postoperative opioid consumption was associated with greater odds of a subsequent persistent opioid use of up to 6 months (odds ratio 1.03, 95% CI: 1.00, 1.07, P = .05).

CONCLUSION

In this retrospective study of children and adolescents who had undergone a major oncologic surgery, higher in-patient pain scores and higher postoperative opioid consumption were associated with a persistent opioid use of up to 6 months.

The analgesic effect of intravenous methylprednisolone on acute neuropathic pain with allodynia due to central cord syndrome: a retrospective study

Background

Central cord syndrome (CCS) may be associated with severe neuropathic pain that often resists to conventional pain therapy regimens and affects the patients’ quality of life (QoL) seriously. Current treatments for CCS-associated neuropathic pain have limited evidence of efficacy. This retrospective study was performed to present the effects of early treatment with methylprednisolone (MP) on acute neuropathic pain relief and the QoL in CCS patients.

Patients and methods

Data were collected from the medical records of CCS patients who suffered from acute neuropathic pain with allodynia. All the patients received intravenous MP treatment for up to 1 week. Patients were evaluated with standard measures of efficacy: neuropathic pain intensity, the area of allodynia, and the QoL at baseline, daily treatment, and at 1 and 3 months after the end of MP treatment.

Results

Thirty-four eligible patients were enrolled in our study. By the end of MP treatment, the proportion of patients who gained total or major (visual analog scale [VAS] score decreased by 50% or more) allodynia relief from the treatment was 91.18%, and a decrease in spontaneous pain was also observed. Moreover, this study showed MP could significantly improve the QoL of patients based on McGill Pain Questionnaire Short Form and EuroQol Five Dimensions Questionnaire. Four patients (11.76%) during MP treatment experienced mild or moderate side effects. None of the patients manifested CCS-associated neuropathic pain recurrence and MP-associated side effects at follow-up.

Conclusion

The current results suggested that MP offered an effective therapeutic alternative for relieving CCS-associated acute neuropathic pain with allodynia. Given the encouraging results of this study, it would be worthwhile to confirm these results in randomized placebo-controlled clinical trials.

Treatment of Neuropathic Pain with Venlafaxine: A Systematic Review

Objective

To investigate the efficacy of venlafaxine for neuropathic pain and review literature to determine if the medication provides adequate neuropathic pain relief.

Methods

Literature was reviewed on MEDLINE using various key words. These key words include: "venlafaxine and pain," "venlafaxine ER and pain," "venlafaxine XR and pain," "venlafaxine and neuropathic pain," "venlafaxine and neuropathy," "SSRI and neuropathic pain," "SSRI and neuropathy," "SNRI and neuropathic pain," "SNRI and neuropathy," "serotonin reuptake inhibitor and neuropathic pain," "serotonin reuptake inhibitor and neuropathy," "serotonin norepinephrine reuptake inhibitor and neuropathic pain" and "serotonin norepinephrine reuptake inhibitor and neuropathy." Using this guideline, 13 articles were reviewed.

Results

A total of 13 studies reviewed, which are organized by date and diagnosis. It is evident that in the majority of studies, when compared with a placebo, there was a clinical significant reduction in neuropathic pain relief when using venlafaxine. Additionally, one study showed even more significant pain relief when using higher doses of venlafaxine (at least 150 mg). However, when compared with alternative neuropathic medications, venlafaxine for the most part did not perform any better in terms of efficacy.

Conclusion

In conclusion, venlafaxine is a safe and well-tolerated analgesic drug for the symptomatic treatment of neuropathic pain, and there is limited evidence that high-dose venlafaxine (150 mg/day) can be even more beneficial. While the present evidence is quite encouraging regarding venlafaxine's use for neuropathic pain, further research is needed to continue to expand on these findings, particularly when in consideration with other possible pharmacological agents.

Development and Acceptability Assessment of a Self-Management Intervention to Prevent Acute to Chronic Pain Transition after Major Lower Extremity Trauma

PURPOSE

Transition from acute to chronic pain often occurs after major lower extremity trauma. Chronic pain has been found to negatively affect daily functioning, including the capacity to work and quality of life. Empirical data and an acceptability assessment were used to develop a self-management intervention aimed at preventing acute to chronic pain transition after major lower extremity trauma (i.e., iPACT-E-Trauma).

METHODS

Evidence from previous studies on preventive self-management interventions, combined with a biopsychosocial conceptual framework and clinical knowledge, helped define the key features of the preliminary version. Then a mixed-methods design was used to assess the acceptability of iPACT-E-Trauma by clinicians and patients.

RESULTS

The key features of the preliminary version of iPACT-E-Trauma were assessed as acceptable to very acceptable by clinicians and patients. After clinician assessment, intervention activities were simplified and session duration was reduced. Patient acceptability assessment of iPACT-E-Trauma led to the tailoring of key intervention features, based on determinants such as pain intensity and the implementation of self-management behaviors between intervention sessions. Web-based sessions were also developed to facilitate iPACT-E-Trauma delivery.

CONCLUSION

This study outlines the process involved in the development of an intervention to prevent chronic pain in patients with lower extremity trauma. Relevant information is provided to nurses and interdisciplinary teams on a self-management intervention to prevent the transition from acute to chronic pain in the trauma population.

Uses of fluoxetine in nociceptive pain management: A literature overview

Fluoxetine is one of the top ten prescribed antidepressants. Other therapeutic applications were approved for fluoxetine including, anxiety disorders, bulimia nervosa, and premature ejaculation. However, the role of fluoxetine in nociceptive pain management is still unclear. In this review, we discuss an overview of five possible roles of fluoxetine in pain management: intrinsic antinociceptive effect, enhancement of acute opioid analgesia, attenuation of tolerance development to opioid analgesia, attenuation of dependence development and abstinence syndrome, and attenuation of opioid induced hyperalgesia. Conflicting data were reported about fluoxetine intrinsic anti-nociceptive effect in preclinical and clinical studies except for inflammatory pain. Similar controversy was described in preclinical and clinical studies which explored the possible enhancement of opioid analgesia by fluoxetine co-administration. However, fluoxetine was found to have a promising effect on opioid tolerance and dependence in animal and human studies. Regarding opioid induced hyperalgesia, no studies examined fluoxetine effects in this regard. Our literature review revealed that, the most likely beneficial use of fluoxetine in nociceptive pain management is for alleviation of inflammatory pain and attenuation of opioid tolerance and dependence. Non-steroidal anti-inflammatory and corticosteroids carry many adverse effects and toxicities. Effective alleviation of opioid tolerance and dependence represents a huge health burden and growing unmet medical need. Moreover, most agents used to attenuate these phenomena are either experimental or poorly tolerable drugs which limit their transitional value. Fluoxetine offers an effective, safe, and tolerable alternative for management of both inflammatory pain and opioid tolerance and dependence presently available to clinicians.

Treatment for neuropathic pain and chronic inflammation using LASER in animal models

The ST36 (Zusanli) acupuncture point is used to treat inflammatory processes, pain and gastrointestinal disturbs. For this reason, the aim of the present study was to evaluate the antinociceptive effect of Low-level Laser Treatment (LLLT) on ST36 acupoint using models of chronic nociception and inflammation. Male Swiss mice were treated with LLLT on ST36 30 minutes before the mechanical allodynia (von Frey) performed on the partial sciatic nerve ligation (PSNL) method and Complete Freund's Adjuvant (CFA). The results demonstrated that application of LLLT on ST36 inhibited the mechanical allodynia response induced by PSNL and CFA, with total reversion at 30 minutes after application. Long-term treatment of animals with LLLT on the same acupoint, once a day, also reduced the PNSL and CFA-induced mechanical allodynia response during 8 days of treatment. As conclusion, the results demonstrated that photonic stimulus on ST36 with LLLT produces antinociceptive effect in chronic models of nociception and inflammation. These findings suggest that LLLT may constitute an important therapeutic alternative to control chronic pain.

Psychosocial predictors in the transition from acute to chronic pain: a systematic review

Chronic non-cancer pain (CNCP) is a major health problem which psychosocial factors have significant implications in. There is a gap in regards to evidence for the prevention of chronicity specifically addressing psychological and social domains. Four databases were searched with terms related to "psychosocial", "acute pain", and "chronic pain". A total of 1,389 studies were identified in which titles, abstracts, and full texts were assessed for inclusion criteria. A data template was used to capture pertinent details, and overall themes and patterns were organized according to type of pain examined and psychosocial variables measured. Of the 18 articles that met inclusion criteria, fifteen (83%) of the articles reported an association between psychosocial factors and chronicity. A total of 5 of the studies (29%) demonstrated that depression was a possible predictor and 6 (35%) of the studies found fear-avoidance to be associated with chronicity. This review provides evidence that psychosocial factors are associated with chronicity within CNCP. These results suggest a need for targeting psychosocial predictors in prevention and early intervention through clinical guidelines and a national strategy to support a cultural change in pain care.

Chronification of Pain: Mechanisms, Current Understanding, and Clinical Implications

PURPOSE OF REVIEW

The development of acute to chronic pain involves distinct pathophysiological changes in the peripheral and central nervous systems. This article reviews the mechanisms, etiologies, and management of chronic pain syndromes with updates from recent findings in the literature.

RECENT FINDINGS

Chronic post-surgical pain (CPSP) is not limited to major surgeries and can develop after smaller procedures such as hernia repairs. While nerve injury has traditionally been thought to be the culprit for CPSP, it is evident that nerve-sparing surgical techniques are not completely preventative. Regional analgesia and agents such as ketamine, gabapentinoids, and COX-2 inhibitors have also been found to decrease the risks of developing chronic pain to varying degrees. Yet, given the correlation of central sensitization with the development of chronic pain, it is reasonable to utilize aggressive multimodal analgesia whenever possible. Development of chronic pain is typically a result of peripheral and central sensitization, with CPSP being one of the most common presentations. Using minimally invasive surgical techniques may reduce the risk of CPSP. Regional anesthetic techniques and preemptive analgesia should also be utilized when appropriate to reduce the intensity and duration of acute post-operative pain, which has been correlated with higher incidences of chronic pain.

Assessment and manifestation of central sensitisation across different chronic pain conditions

Different neuroplastic processes can occur along the nociceptive pathways and may be important in the transition from acute to chronic pain and for diagnosis and development of optimal management strategies. The neuroplastic processes may result in gain (sensitisation) or loss (desensitisation) of function in relation to the incoming nociceptive signals. Such processes play important roles in chronic pain, and although the clinical manifestations differ across condition processes, they share some common mechanistic features. The fundamental understanding and quantitative assessment of particularly some of the central sensitisation mechanisms can be translated from preclinical studies into the clinic. The clinical perspectives are implementation of such novel information into diagnostics, mechanistic phenotyping, prevention, personalised treatment, and drug development. The aims of this paper are to introduce and discuss (1) some common fundamental central pain mechanisms, (2) how they may translate into the clinical signs and symptoms across different chronic pain conditions, (3) how to evaluate gain and loss of function using quantitative pain assessment tools, and (4) the implications for optimising prevention and management of pain. The chronic pain conditions selected for the paper are neuropathic pain in general, musculoskeletal pain (chronic low back pain and osteoarthritic pain in particular), and visceral pain (irritable bowel syndrome in particular). The translational mechanisms addressed are local and widespread sensitisation, central summation, and descending pain modulation.

Significance

Central sensitisation is an important manifestation involved in many different chronic pain conditions. Central sensitisation can be different to assess and evaluate as the manifestations vary from pain condition to pain condition. Understanding central sensitisation may promote better profiling and diagnosis of pain patients and development of new regimes for mechanism based therapy. Some of the mechanisms underlying central sensitisation can be translated from animals to humans providing new options in development of therapies and profiling drugs under development.

Postpartum Pain in the Community Among Migrant and Non-migrant Women in Canada

International migrant women of childbearing age represent a large proportion of immigrants to high-income countries, yet research focusing on their postpartum health is limited. We investigated predictive factors for breast and non-breast pain 1 week post-birth in migrant and non-migrant women in Canada. Among migrant women, difficulty accessing health services; being from a middle-or high-income country; poor functionality in English and French; living with the father of their infant; and having no regular care provider were predictive of breast pain. Among non-migrant women, difficulties accessing health services, multiparity and prenatal education were predictive of breast pain, while receiving an epidural and having no regular care provider were predictive of non-breast pain. Among both groups, difficulties accessing health services and having no regular care provider were predictive of breast pain, while second degree or higher perineal tearing was predictive of non-breast pain. Migration-specific indicators should be considered in postpartum care planning.

Dexamethasone-suppressed Salivary Cortisol and Pain Sensitivity in Female Twins

OBJECTIVES

Hypothalamic-pituitary-adrenal (HPA) axis dysregulation is associated with chronic pain. Studying pain sensitivity and the HPA axis could elucidate the role of stress in chronic pain development, which might be influenced by familial factors, including genes.

METHODS

Associations between pain sensitivity and salivary cortisol and familial confounding in these associations were examined in 88 female, community-based twin pairs (75% monozygotic, mean age 29 y). Cortisol was assessed after 0.25 mg dexamethasone (DEX), recovery from 0.25 mg DEX, and after 0.5 mg DEX. Cold pressor task (CPT) pain ratings were obtained at threshold and at tolerance. Conditioned pain modulation (CPM) was examined using thermal heat as the testing stimulus and hot water as the conditioning stimulus. Generalized estimating equation models were used and adjusted for baseline pain rating, age, and other relevant covariates.

RESULTS

After controlling for baseline cortisol, greater cortisol suppression following DEX administration and lower recovery cortisol levels were associated with higher pain ratings at tolerance during the CPT (Bs=-2.42 to -17.82; Ps=0.031 to<0.001) as well as with reduced CPM (Bs=-0.92 to -1.68; Ps=0.003 to 0.046). Interestingly, familial confounding was evident in the CPT and CPM during recovery from DEX administration, but not immediately following DEX administration.

DISCUSSION

These findings contribute to understanding possible mechanisms underlying chronic pain by demonstrating that HPA axis response to negative feedback is related to pain sensitivity.

Cardioprotection induced in a mouse model of neuropathic pain via anterior nucleus of paraventricular thalamus

Myocardial infarction is the leading cause of death worldwide. Restoration of blood flow rescues myocardium but also causes ischemia-reperfusion injury. Here, we show that in a mouse model of chronic neuropathic pain, ischemia-reperfusion injury following myocardial infarction is reduced, and this cardioprotection is induced via an anterior nucleus of paraventricular thalamus (PVA)-dependent parasympathetic pathway. Pharmacological inhibition of extracellular signal-regulated kinase activation in the PVA abolishes neuropathic pain-induced cardioprotection, whereas activation of PVA neurons pharmacologically, or optogenetic stimulation, is sufficient to induce cardioprotection. Furthermore, neuropathic injury and optogenetic stimulation of PVA neurons reduce the heart rate. These results suggest that the parasympathetic nerve is responsible for this unexpected cardioprotective effect of chronic neuropathic pain in mice.

Various forms of preconditioning can prevent ischemic-reperfusion injury after myocardial infarction. Here, the authors show that in mice, the presence of chronic neuropathic pain can have a cardioprotective effect, and that this is dependent on neural activation in the paraventricular thalamus.

The effect of psychological interventions on the prevention of chronic pain in adults: a systematic review protocol

BACKGROUND

Numerous psychological risk and protective factors have been identified as contributing to or preventing the development of the prevalent issue of chronic pain. Systematic reviews of studies on psychological interventions that tackle these factors have shown limited effects on chronic pain. Therefore, implementing psychological interventions before pain becomes chronic has been put forward. However, the efficacy of such interventions in preventing the transition from acute to chronic pain has not yet been systematically assessed.

METHODS

The aims of this systematic review are to assess the effects of psychological interventions applied in the acute pain phase on pain severity as well as on physical, psychological, and social functions at 3 months and beyond. Randomized controlled trials including psychological intervention as a treatment of primary interest and participants with pain of less than 3 months duration will be considered. The following comparisons will be undertaken: psychological interventions with (1) standard treatment, (2) information, (3) waiting-list, and (4) active treatment. The primary outcome will be pain severity using indicators such the presence or absence of pain and self-report measures such as the numeric pain intensity rating scale. Secondary outcomes will include pain-related disability, mood, coping with pain, quality of life, health care utilization, and work capability. A systematic review of English and French articles in MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Central Register of Controlled Trials will be conducted without date restriction. Extracted data will include demographics and clinical characteristics, sample size, intervention and control group types, assessment tools used, time interval of measurement, fidelity of the intervention, and attrition rate. Standardized mean differences (SMD) and risk ratios with 95% confidence intervals (CI) will be used to assess treatment effects.

DISCUSSION

This systematic review is the first in examining the effects of psychological interventions implemented in the acute pain phase with the objective of preventing chronic pain. Results of this systematic review could provide information on psychological intervention characteristics that are most helpful for individuals with pain and guidance as to when such interventions should be applied in the continuum of care.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016049312.

Prediction of persistent post-operative pain: Pain-specific psychological variables compared with acute post-operative pain and general psychological variables

BACKGROUND

Psychological variables and acute post-operative pain are of proven relevance for the prediction of persistent post-operative pain. We aimed at investigating whether pain-specific psychological variables like pain catastrophizing add to the predictive power of acute pain and more general psychological variables like depression.

METHODS

In all, 104 young male patients undergoing thoracic surgery for pectus excavatum correction were studied on the pre-operative day (T0) and 1 week (T1) and 3 months (T2) after surgery. They provided self-report ratings (pain-related: Pain Catastrophizing Scale, Pain Anxiety Symptoms Scale = PASS, Pain Vigilance and Awareness Questionnaire = PVAQ; general psychological: Screening for Somatoform Symptoms, State-Anxiety Inventory-X1, Center for Epidemiologic Studies Depression Scale = CES-D). Additional predictors (T1) as well as criterion variables (T2) were pain intensity (Numerical Rating Scale) and pain disability (Pain Disability Index).

RESULTS

Three months after surgery, 25% of the patients still reported clinically relevant pain (pain intensity ≥3) and over 50% still reported pain-related disability. Acute post-operative pain as well as general psychological variables did not allow for a significant prediction of persistent post-operative pain; in contrast, pain-related psychological variables did. The best single predictors were PASS for pain intensity and PVAQ for pain disability.

CONCLUSIONS

Pain-related psychological variables derived from the fear-avoidance model contributed significantly to the prediction of persistent post-operative pain. The best possible compilation of these measures requires further research. More general psychological variables may become relevant predictors later in the medical history.

SIGNIFICANCE

Our results suggest that pain-specific psychological variables such as pain anxiety and pain hypervigilance add significantly to the prediction of persistent post-operative pain and might even outperform established predictors such as acute pain and general psychological variables. Clinicians might benefit from the development of time-economic screening tools based on these variables.

Provoked vestibulodynia: current perspectives

Provoked vestibulodynia (PVD) refers to vulvar pain of at least 3 months duration, localized to the vestibule, provoked by touch and sexual activity and occurring in the absence of a clear identifiable cause. The clinical spectrum ranges from mild with distressing discomfort through to severe and disabling pain. Current understanding is that PVD is one of many chronic pain conditions characterized by sensitization of peripheral and central nociceptive pathways, with pain arising due to dysfunctional neuronal activity in the absence of painful stimuli. Pathophysiology is not well understood but is likely a complex interplay of environmental, genetic, psychological and immune factors. Care is multidisciplinary and follows general principles of chronic pain management with the addition of specific therapy tailored to address pelvic floor overactivity, and sexual and relationship difficulties. More recently, the therapeutic use of placebo is gaining traction in chronic pain research and is a very promising adjunctive therapy. The majority of women with PVD are managed outside of tertiary clinic settings, and care depends on availability and affordability of specialized services; however, much can be done by the primary health provider. PVD is common, and highly treatable, especially with early intervention, but unfortunately, many clinicians are unaware of this condition, and the biggest hurdle for women accessing treatment is obtaining a diagnosis. With treatment, most women can expect significant improvement, often with fairly simple interventions, although some women will benefit from referral to specialized centers. The aims of this article are twofold: firstly, to summarize current literature concerning PVD pathophysiology and management; secondly, to provide a framework for clinicians unfamiliar with vulvar medicine to understand and manage PVD.

Photobiomodulation therapy by NIR laser in persistent pain: an analytical study in the rat

Over the past three decades, physicians have used laser sources for the management of different pain conditions obtaining controversial results that call for further investigations. In order to evaluate the pain relieving possibilities of photobiomodulation therapy (PBMT), we tested two near infrared (NIR) laser systems, with different power, against various kinds of persistent hyperalgesia animal models. In rats, articular pain was reproduced by the intra-articular injection of sodium monoiodoacetate (MIA) and complete Freund's adjuvant (CFA), while compressive neuropathy was modelled by the chronic constriction injury of the sciatic nerve (CCI). In MIA and CFA models, (NIR) laser (MLS-Mphi, ASA S.r.l., Vicenza, Italy) application was started 14 days after injury and was performed once a day for a total of 13 applications. In MIA-treated animals, the anti-hyperalgesic effect of laser began 5 min after treatment and vanished after 60 min. The subsequent applications evoked similar effects. In CFA-treated rats, laser efficacy started 5 min after treatment and disappeared after 180 min. In rats that underwent CCI, two treatment protocols with similar fluence but different power output were tested using a new experimental device called Multiwave Locked System laser (MLS-HPP). Treatments began 7 days after injury and were performed during 3 weeks for a total of 10 applications. Both protocols reduced mechanical hyperalgesia and hindlimb weight bearing alterations until 60 min after treatment with a higher efficacy recorded for the animals treated using the higher power output. In conclusion, this study supports laser therapy as a potential treatment for immediate relief of chronic articular or neuropathic pain.

The effects of food on opioid-induced nausea and vomiting and pharmacological parameters: a systematic review

Opioids remain the standard of care for treating moderate to severe pain resulting from surgery or injury in cases of acute pain, and are recommended for patients who have not responded to nonopioid analgesics. Effective management of pain has an impact on clinical course and often depends on achieving an acceptable balance between opioid efficacy, safety, and tolerability. Common opioid-related adverse events such as nausea and vomiting are associated with an overall lower achievement of effective pain management and patient satisfaction. However, in practice, clinicians employ various strategies to maximize efficacy, minimize these adverse effects, and ensure the careful, judicious, and evidence-based use of opioids for patients who require them. Typical strategies for management and minimization of these types of adverse events include dose reduction, dose titration, opioid rotation, prescription for an antiemetic, and recommending the patient take opioids with food. Overall, the most straightforward approach that clinicians tend to employ that does not require additional visits or adjustment of prescriptions, is to recommend patients take opioids with food. However, given the current climate with opioids, it is critical and imperative that decisions for use of opioids be grounded in a solid and thorough evidence-base. In fact, several opioids are recommended to be taken explicitly with or without food because of interactions with abuse-deterrent technologies that can cause increased adverse events or inadequate analgesia. Therefore, we sought to review, synthesize, and summarize the literature for randomized, controlled trials and other studies to support the hypothesis that taking opioids with food reduces opioid-related events such as nausea and vomiting. Based on the current evidence we surveyed, the recommendation to take opioids with food does not appear to consistently and unequivocally reduce nausea and vomiting and, in many cases, increases the frequency of these adverse events in the studies we examined.

Chronic scrotal pain and microsurgical spermatic cord denervation: tricks of the trade

Every practicing urologist encounters patients complaining of chronic scrotal content pain (CSCP). This condition can be equally frustrating for both patients and clinicians as there are no clear treatment guidelines, or pathways, for urologists to follow. As a result, most patients typically seek out multiple providers without improvements in their symptoms. Fortunately, microsurgical spermatic cord denervation (MSCD) is becoming an accepted, reliable and reproducible technique for definitively addressing CSCP in select patients. This manuscript reviews the background, effectiveness and current practice guidelines for scrotal pain in general, and MSCD in particular. Technical insights into how this technique can be performed both safely, and efficaciously, are provided. Finally, the manuscript presents a simple, yet detailed, easy to follow treatment algorithm to aid all urologists in the management of patients presenting with chronic pain.

The Efficacy of Systemic Lidocaine in the Management of Chronic Pain: A Literature Review

Context

Despite recent advances in the understanding of the chronic pain concept, its diagnosis and management remains a daily challenge for clinicians and patients. Based on the published literature, this review discusses and tries to organize the current knowledge and the up-to-date clinical experience about the efficacy and safety of the use of intravenous lidocaine in treatment and prevention of chronic pain.

Evidence Acquisition

To prepare this narrative review, we performed an in depth literature review using the PubMed searching engine. We extracted all relevant articles published in English, up to April 2016.

Results

Lidocaine, administered as transdermal patch or intravenous lidocaine, is a safe and effective modality in the treatment of post-herpetic neuralgia (PHN), complex regional pain syndrome, as well and for prevention of chronic pain. It may be effective in the management of neuropathic pain syndromes, chronic pain, post-operative pain, and refractory cancer pain.

Conclusions

Intravenous lidocaine and lidocaine patch are effective and safe for the treatment of several chronic or neuropathic pain syndromes. The use of lidocaine during surgery could prevent the development of some chronic post-surgical pain syndromes.

Evidence and consensus recommendations for the pharmacological management of pain in India

Despite enormous progress in the field of pain management over the recent years, pain continues to be a highly prevalent medical condition worldwide. In the developing countries, pain is often an undertreated and neglected aspect of treatment. Awareness issues and several misconceptions associated with the use of analgesics, fear of adverse events - particularly with opioids and surgical methods of analgesia - are major factors contributing to suboptimal treatment of pain. Untreated pain, as a consequence, is associated with disability, loss of income, unemployment and considerable mortality; besides contributing majorly to the economic burden on the society and the health care system in general. Available guidelines suggest that a strategic treatment approach may be helpful for physicians in managing pain in real-world settings. The aim of this manuscript is to propose treatment recommendations for the management of different types of pain, based on the available evidence. Evidence search was performed by using MEDLINE (by PubMed) and Cochrane databases. The types of articles included in this review were based on randomized control studies, case-control or cohort studies, prospective and retrospective studies, systematic reviews, meta-analyses, clinical practice guidelines and evidence-based consensus recommendations. Articles were reviewed by a multidisciplinary expert panel and recommendations were developed. A stepwise treatment algorithm-based approach based on a careful diagnosis and evaluation of the underlying disease, associated comorbidities and type/duration of pain is proposed to assist general practitioners, physicians and pain specialists in clinical decision making.

5-HT1A Receptors Mediate Analgesia Induced by Emulsified Sevoflurane in Thermal Nociception but Have Little Effect on Chemical Nociception

OBJECTIVE

The study aimed to investigate the relationship between the analgesic effect of sevoflurane and 5-serotonin receptor 1A (5-HT1A R) in the spinal cords of mice.

METHODS

Analgesic mouse models were established by intraperitoneal injection of emulsified sevoflurane, and the influence of p-MPPF (a specific antagonist of 5-HT1A Rs) intrathecal injection on the changes in tail-flick latency in tail-withdrawal test, pain threshold in hot-plate test (HPPT), and writhing times in acetic acid-induced writhing test were recorded.

RESULTS

Intraperitoneal injection of emulsified sevoflurane alone produced an analgesic effect (p < 0.05). p-MPPF (2, 4, and 8 μg) alone had no impact on tail-flick latency, HPPT, and writhing times in mice (p > 0.05). The 3 doses of p-MPPF reduced the tail-flick latency or HPPT. p-MPPF 8 μg can increase the writhing times (p < 0.05) in analgesic mice with sevoflurane, while p-MPPF 2 and 4 μg did not affect the writhing times.

CONCLUSION

5-HT1A Rs in the spinal cord may be an important target for the analgesic effect of sevoflurane on the thermal nociception, but it has little relation to the anti-chemical chemical nociceptive effect of sevoflurane.

Assessing and Managing Acute Pain: A Call to Action

: Acute pain, which is usually sudden in onset and time limited, serves a biological protective function, warning the body of impending danger. However, while acute pain often resolves over time with normal healing, unrelieved acute pain can disrupt activities of daily living and transition to chronic pain. This article describes the effects of unrelieved acute pain on patients and clinical outcomes. The authors call on nurses to assess and manage acute pain in accordance with evidence-based guidelines, expert consensus reports, and position statements from professional nursing organizations in order to minimize the likelihood of its becoming chronic.

Psychological and endocrine factors and pain after mastectomy

BACKGROUND

This prospective study was designed to examine the associations of demographic, clinical, psychological and neuroendocrine factors with acute and chronic post-operative pain following partial mastectomy.

METHODS

Sixty-four female patients scheduled for partial mastectomy were enrolled. Pre-operative anxiety/depression was assessed, using the Hospital Anxiety and Depression Scale (HADS). Pre-operative 24-h urinary cortisol levels were measured 2 days before surgery. Post-operative pain was examined using a visual analog scale (VAS) for acute pain on 0-2 post-operative day (POD), and a short-form McGill Pain Questionnaire for chronic pain at 6 months after surgery. In the last 29 subjects, post-operative 24-h urinary cortisol levels were also measured on 0 POD and were subjected to correlation analysis.

RESULTS

Multivariate logistic regression analysis revealed that lower pre-operative cortisol secretion and greater pre-operative anxiety were significantly associated with an increased risk of moderate to severe acute post-operative pain [Odds Ratio (95% Confidence Interval); 0.96 (0.92-0.98), and 1.24 (1.04-1.54)], and that patients with greater pre-operative anxiety and moderate to severe acute pain were more likely to develop chronic post-operative pain [OR (95% CI); 1.63 (1.23-2.40), and 5.07 (1.30-24.6)]. Correlational analysis demonstrated that the post-operative cortisol level was inversely correlated with pre-operative anxiety and the intensity of acute post-operative pain (r = -0.40, p < 0.05, and r = -0.50, p < 0.01), but not with the intensity of chronic pain.

CONCLUSIONS

This study confirms that pre-operative anxiety is associated with both acute and chronic post-operative pain after partial mastectomy. It also suggests that lower perioperative cortisol secretion might be associated with greater acute post-operative pain.

SIGNIFICANCE

Although the associations between psychological stress/stress hormone levels and chronic post-operative pain remain to be determined, pre-operative psychological stress and perioperative cortisol levels are correlated with acute post-operative pain.

Treatment of radiation-induced cystitis and vulvodynia via a ganglion impar block using a lateral approach under computed tomography guidance: a case report

Adjuvant radiation therapy (RT) after colorectal cancer surgery can prevent local recurrence, but has several side effects. Precise injection of drugs into the affected areas is complicated by radiation-induced fibrosis of soft or connective tissue. A 48-year-old woman experienced severe intractable perineal pain, dysuria, urinary urgency, and frequent urination after rectal cancer surgery and adjuvant RT, and was diagnosed with radiation-induced cystitis and vulvodynia. Her symptoms persisted despite two fluoroscopy-guided ganglion impar blocks. Fluoroscopy revealed atypical needle tip positioning and radiolucent dye distribution, presumably due to radiation-induced fibrosis in the target region. We performed two computed tomography (CT)-guided ganglion impar blocks by using a lateral approach, which allowed more accurate po-sitioning of the needle tip. Her pain visual analog score decreased from 9 to 3, and she recently resumed sexual intimacy. CT guidance is a viable alternative to fluoroscopy guidance when performing ganglion impar blocks in fibrotic areas.

Post-operative effectiveness of continuous wound infiltration, continuous epidural infusion and intravenous patient-controlled analgesia on post-operative pain management in patients undergoing spinal surgery

BACKGROUND AND AIMS

Very few studies have compared continuous wound infiltration (CWI), continuous epidural infusion (CEI) and intravenous Patient Controlled Analgesia (PCA) with morphine in spine surgery. This study compared these modalities in patients undergoing microdissectomy.

METHODS

This prospective, randomized control trial was conducted on 75 patients of American Society of Anesthesiologists' physical status I or II undergoing microdiscectomy. Patients in all the three groups received morphine 1 mg IV, with a lockout period of 10 min after each bolus, and the maximum allowed dose was 15 mg/5 h postoperatively. Patients in Group A received CWI with 0.25% levobupivacaine 20 mL as bolus after extubation followed by infusion at 5 mL/h. Group B received CEI with 0.25% levobupivacaine at 5 mL/h. Patients in Group C received intravenous (IV) morphine by PCA pump only. The primary end points were static and dynamic visual analogue scores (VAS) and postoperative pain scores. Secondary observations were postoperative morphine consumption at 8 h, 24 h and 48 h, and patient satisfaction.

RESULTS

Group A showed greater analgesic effects at 12 h (P < 0.02), 24 h (P < 0.03), 36 h (P < 0.008) and 48 h (P < 0.007) when compared to the other two techniques, as pain scores were less in group A as compared to group B and C. The requirement of postoperative intravenous morphine (mg) was 18 ± 12.82, 22.92 ± 9.88, 41.56 ± 8.83 for groups A, B and C after 48 h (P < 0.001).

CONCLUSION

Continuous wound infiltration is an effective postoperative pain control technique with minimal side effects, after spinal surgery.

Genes associated with persistent lumbar radicular pain; a systematic review

Background

The aim of the present study was to provide an overview of the literature addressing the role of genetic factors and biomarkers predicting pain recovery in newly diagnosed lumbar radicular pain (LRP) patients.

Methods

The search was performed in Medline OVID, Embase, PsycInfo and Web of Science (2004 to 2015). Only prospective studies of patients with LRP addressing the role of genetic factors (genetic susceptibility) and pain biomarkers (proteins in serum) were included. Two independent reviewers extracted the data and assessed methodological quality.

Results

The search identified 880 citations of which 15 fulfilled the inclusion criteria. Five genetic variants; i.e., OPRM1 rs1799971 G allele, COMT rs4680 G allele, MMP1 rs1799750 2G allele, IL1α rs1800587 T allele, IL1RN rs2234677 A allele, were associated with reduced recovery of LRP. Three biomarkers; i.e., TNFα, IL6 and IFNα, were associated with persistent LRP.

Conclusion

The present results indicate that several genetic factors and biomarkers may predict slow recovery in LRP. Still, there is a need for replication of the findings. A stricter use of nomenclature is also highly necessary.

Trial registration

The review is registered PROSPERO 20^th of November 2015. Registration number is CRD42015029125.