Post-surgical neuropathic pain

Serotonin norepinephrine reuptake inhibitors in managing neuropathic pain following spinal and non-spinal surgery: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

While serotonin norepinephrine reuptake inhibitors (SNRIs) offer promise in managing Post-surgical neuropathic pain (PSNP), uncertainties remain. This study aims to evaluate the effectiveness and adverse events of SNRIs in managing PSNP.

METHODS

Systematic searches of PubMed, Embase, and Cochrane databases up to January 1st 2023 identified randomized controlled trials (RCTs) comparing SNRIs to placebo for PSNP. The primary outcome measures were pain at rest and adverse events post-surgery. Subgroup analyses were conducted based on surgical type and specific SNRIs.

RESULTS

A total of 19 RCTs, encompassing 1440 participants (719 in the SNRI group vs 721 in the placebo group), met the inclusion criteria and were included. The pooled results demonstrated that pain scores were significantly lower in patients treated with SNRIs at 2 hours (MD:-0.26; 95%CI: -0.47 to -0.04; p=0.02), 6 hours (MD:-0.68; 95%CI: -1.01 to -0.34; p<0.0001), 24 hours (MD:-0.54; 95%CI: -0.99 to -0.09; p=0.02), and 48 hours (MD:-0.66; 95%CI: -1.23 to -0.10; p=0.02) post-surgery. In terms of adverse events, dizziness (OR:2.53; 95%CI: 1.34-4.78; p=0.004) and dry mouth (OR:2.21; 95%CI: 1.25-3.92; p=0.007) were significantly higher in the SNRIs group. Subgroup analysis showed that SNRI was found to significantly lower the 24-hour pain score after spinal surgery (MD:-0.45; 95%CI: -0.84 to -0.05; p=0.03). Duloxetine (MD:-0.63; 95%CI: -1.15 to -0.11; p=0.02) had a significant effect in lowering the 24-hour pain score at rest compared to placebo, whereas venlafaxine did not.

CONCLUSIONS

SNRIs yielded considerable pain score reductions across multiple post-surgical intervals, although accompanied by an increased incidence of dizziness and dry mouth.

Unveiling the Pain Relief Potential: Harnessing Analgesic Peptides from Animal Venoms

The concept of pain encompasses a complex interplay of sensory and emotional experiences associated with actual or potential tissue damage. Accurately describing and localizing pain, whether acute or chronic, mild or severe, poses a challenge due to its diverse manifestations. Understanding the underlying origins and mechanisms of these pain variations is crucial for effective management and pharmacological interventions. Derived from a wide spectrum of species, including snakes, arthropods, mollusks, and vertebrates, animal venoms have emerged as abundant repositories of potential biomolecules exhibiting analgesic properties across a broad spectrum of pain models. This review focuses on highlighting the most promising venom-derived toxins investigated as potential prototypes for analgesic drugs. The discussion further encompasses research prospects, challenges in advancing analgesics, and the practical application of venom-derived toxins. As the field continues its evolution, tapping into the latent potential of these natural bioactive compounds holds the key to pioneering approaches in pain management and treatment. Therefore, animal toxins present countless possibilities for treating pain caused by different diseases. The development of new analgesic drugs from toxins is one of the directions that therapy must follow, and it seems to be moving forward by recommending the composition of multimodal therapy to combat pain.

Identifying risk factors for chronic postsurgical pain and preventive measures: a comprehensive update

INTRODUCTION

Chronic postsurgical pain (CPSP) is a prevalent condition that can diminish health-related quality of life, cause functional deficits, and lead to patient distress. Rates of CPSP are higher for certain types of surgeries than others (thoracic, breast, or lower extremity amputations) but can occur after even uncomplicated minimally invasive procedures. CPSP has multiple mechanisms, but always starts as acute postsurgical pain, which involves inflammatory processes and may encompass direct or indirect neural injury. Risk factors for CPSP are largely known but many, such as female sex, younger age, or type of surgery, are not modifiable. The best strategy against CPSP is to quickly and effectively treat acute postoperative pain using a multimodal analgesic regimen that is safe, effective, and spares opioids.

AREAS COVERED

This is a narrative review of the literature.

EXPERT OPINION

Every surgical patient is at some risk for CPSP. Control of acute postoperative pain appears to be the most effective approach, but principles of good opioid stewardship should apply. The role of regional anesthetics as analgesics is gaining interest and may be appropriate for certain patients. Finally, patients should be better informed about their relative risk for CPSP.

Preoperative anxiety on postoperative pain in craniotomy patients

Aim: This study aimed to determine preoperative anxiety and pain levels in patients who underwent craniotomy and investigate the effects on the development of postoperative acute-chronic pain. Materials and Methods: In this prospective, observational study, STAI-I (State-Trait Anxiety Inventory) and STAI-II were used to measure preoperative anxiety levels in a total of 104 patients who underwent craniotomy, and a visual analog score (VAS) was used to determine pain. Demographic data of the patients, ASA (American Society of Anesthesiologists) scores, comorbidities, preoperative and postoperative VAS scores, cause of preoperative anxiety, type, and duration of operation were recorded. Results: The mean values of STAI tests showed that 31.3% of our patients had mild preoperative anxiety, 58.7% had moderate and 10% had severe preoperative anxiety. In the STAI tests we performed before the operation, the mean values were 44 ± 11.2 for STAI-I and 44.5 ± 9.4 for STAI-II. The causes of preoperative anxiety in patients were determined as surgical operation (35.6%), anesthesia applications (17.3%), insufficient information (11.5%), and the possibility of postoperative pain (3.8%). It was observed that 60.6% of our patients had pain in the preoperative period, 51.9% of patients had acute pain in postoperative the 0th minute, 69.2% in 30th minute, 54.8% in 1st hour, 44.2% in 2nd hour, 34.6% in 24th hour, 22.1% in 48th hour, and 51% of patients had chronic pain in postoperative 6th month. We found a significant relationship between STAI-I and VAS scores at the 48th hour and, between STAI-II and VAS scores at the 2nd, 24th hour, and 6th month (p&lt;0.05). Conclusion: It was observed that craniotomy patients mostly had moderate anxiety and moderate to severe pain before the operation, and moderate-severe acute and chronic pain developed after the operation. A significant correlation was found between preoperative anxiety and postoperative pain.

Postsurgical neuropathic pain: lidocaine 700 mg medicated plaster or oral treatments in clinical practice

Aim: To compare the effectiveness and tolerability of the lidocaine 700 mg medicated plaster (LMP) and oral first-line medications (OM) for the treatment of postsurgical neuropathic pain (PSNP) in routine clinical practice. Patients & methods: Data from a noninterventional, retrospective 24-week cohort study in patients with localized peripheral NP refractory to at least one recommended OM using anonymized German Pain eRegistry data were retrieved. A subgroup analysis was conducted on 531 datasets of PSNP patients. Results: Pain relief, improvements in pain-related impairments of daily living and quality of life, and tolerability were significantly greater under LMP than under OM (p < 0.001 for all parameters). Conclusion: These real-world data show the effectiveness and good tolerability of LMP for PSNP treatment in routine clinical practice.

Considerations for Better Management of Postoperative Pain in Light of Chronic Postoperative Pain: A Narrative Review

Chronic postoperative pain (CPOP) is prevalent, with particularly high rates in breast surgery, thoracotomy, and amputation. As the world emerges from the coronavirus disease 2019 (COVID-19) lockdowns, it is expected that there will be an increase in surgical procedures, elevating the importance of preventing CPOP in the coming years. Risk factors are emerging to better stratify patients at high risk for CPOP. Perioperative analgesia plays an important role in managing acute postoperative pain and in some cases may limit its transition to CPOP. Acute postoperative pain is adaptive, normal, expected, and has a well-defined trajectory, while CPOP is maladaptive and, as a form of chronic pain, is challenging to treat. Good analgesia, early ambulation, and rehabilitation efforts may be helpful in preventing CPOP following certain surgeries. Enhanced Recovery After Surgery (ERAS) protocols present guidance to help promote recovery and prevent CPOP.

Perioperative Dexmedetomidine or Lidocaine Infusion for the Prevention of Chronic Postoperative and Neuropathic Pain After Gynecological Surgery: A Randomized, Placebo-Controlled, Double-Blind Study

Introduction

The transition of acute to chronic postoperative pain (CPP) remains a significant burden to the rehabilitation of patients. The research for adjuvants to prevent CPP continues; among others, dexmedetomidine and lidocaine seem promising agents.

Methods

This is a long-term follow-up of a randomized, placebo-controlled, double-blind study on women who underwent open abdominal gynecological surgery and received dexmedetomidine or lidocaine or placebo infusion perioperatively (n = 81). The effect of these adjuvants on the development of CPP and neuropathic pain was assessed during a 12-month follow-up. Eighty-one (81) women ASA I–II, aged between 30 and 70 years, were randomly assigned to receive either dexmedetomidine (DEX group) or lidocaine (LIDO group) or placebo (CONTROL group) perioperatively. Before anesthesia induction, all patients received a loading intravenous dose of either 0.6 μg/kg dexmedetomidine or 1.5 mg/kg lidocaine or placebo, followed by 0.6 μg/kg/h dexmedetomidine or 1.5 mg/kg/h lidocaine or placebo until last suture. Patients were followed up to obtain the long-term outcomes at 3, 6, and 12 months. At these time-points, pain intensity was assessed with the Numerical Rating Scale, (NRS: 0–10) and the development of neuropathic elements with the Douleur Neuropathique 4 (DN4) score. Prognostic parameters that could affect chronic pain and its components were also identified.

Results

Data from 74 women were analyzed. Dexmedetomidine significantly reduced NRS scores comparing to placebo at 3 months (p = 0.018), while at 6 months, lidocaine was found superior to placebo (p = 0.02), but not to dexmedetomidine, in preventing neuropathic pain (DN4 < 4). Regarding secondary endpoints, higher NRS cough scores at 48 h were associated with statistically significant NRS and DN4 scores at 3, 6, and 12 months (p < 0.02). At 6 months, a statistically significant correlation was also found between higher NRS values and older age (p = 0.020).

Conclusions

Dexmedetomidine was superior to placebo regarding the duration and severity of CPP, while lidocaine exhibited a protective effect against neuropathic elements of CPP.

Trial registration

ClinicalTrials.gov identifier, NCT03363425.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-022-00361-5.

Analgesic and anti-inflammatory effects of modafinil in a mouse model of neuropathic pain: A role for nitrergic and serotonergic pathways

OBJECTIVES

To evaluate the effects of modafinil on neuropathic pain induced by sciatic nerve cuffing in mice, and possible contribution of nitrergic/inflammatory and serotonergic systems.

METHODS

Neuropathic pain was induced by applying a polyethylene cuff around the left sciatic nerve. Seven days later, mice received modafinil (50, 100, and 200 mg/kg; intraperitoneal [i.p.]) and morphine (10 mg/kg, i.p.) as control. Mice also received pretreatments of the nonselective nitric oxide (NO) synthase (NOS) inhibitor L-NAME, the selective neuronal NOS inhibitor 7-nitroindazole, the selective inducible NOS inhibitor aminoguanidine, and the selective serotonin reuptake inhibitor citalopram before modafinil (100 mg/kg). von Frey test was used to evaluate mechanical allodynia. Additionally, sciatic nerves were collected for histopathological analysis. Tissue levels of NO metabolites, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were assessed.

RESULTS

Animals whose sciatic nerves were cuffed had a significantly (P<0.001) decreased paw withdrawal threshold (PWT) compared with the sham-operated group. Modafinil (100 mg/kg) and morphine significantly reversed PWT (P<0.001). Pretreatments with L-NAME, 7-nitroindazole, aminoguanidine, and citalopram in different groups markedly reversed analgesic effects of modafinil. Tissue homogenates of Cuffed sciatic nerves showed significantly higher levels of NO metabolites, TNF-α and IL-6 (P<0.001). Modafinil lowered NO metabolites, TNF-α, and IL-6 levels (P<0.001). Histopathology illustrated marked axonal degeneration and shrinkage in the cuffed sciatic nerve, which were improved in the modafinil-treated group.

CONCLUSIONS

Modafinil exerts analgesic and neuroprotective effects in cuff-induced neuropathic mice via possible involvement of the nitrergic/inflammatory and serotonergic systems.

Capsaicin 179-mg cutaneous patch in the treatment of post-surgical neuropathic pain: a scoping review of current evidence and place in therapy

INTRODUCTION

The use of topical agents has been suggested for post-surgical neuropathic pain. A high-concentration capsaicin 179-mg cutaneous patch (Qutenza™) is licensed in adults for chronic neuropathic pain in the EU, and neuropathic pain with post-herpetic neuralgia and neuropathic pain with diabetic peripheral neuropathy in the USA. This article aims to describe the use of a topical capsaicin 179-mg cutaneous patch in the treatment of PSNP.

AREA COVERED

This narrative review presents the relevant clinical aspects of the use of a topical capsaicin 179-mg cutaneous patch for the treatment of post-surgical neuropathic pain (PSNP). Randomized control trials, observational studies, case series, and reports investigating the clinical use of the capsaicin patch were searched through MEDLINE, EMBASE, AMED, Cochrane Library, CINAHL, Web of Science, and ROAD databases. Trials from citation lists of reviewed articles and hand-searching were added. The search concluded in September 2020. 10/20 articles were considered.

EXPERT OPINION

Some clinical studies demonstrated the efficacy of the capsaicin 179-mg patch in PSNP as monotherapy and concomitant treatment with oral treatments. This topical treatment of PSNP is better tolerated and accepted compared with systemic treatments. To maximize the effectiveness of the treatment, correct administration recommendations should be followed.

Electrical stimulation of the posterior insula induces mechanical analgesia in a rodent model of neuropathic pain by modulating GABAergic signaling and activity in the pain circuitry

The insula has emerged as a critical target for electrical stimulation since it influences pathological pain states. We investigated the effects of repetitive electrical stimulation of the insular cortex (ESI) on mechanical nociception, and general locomotor activity in rats subjected to chronic constriction injury (CCI) of the sciatic nerve. We also studied neuroplastic changes in central pain areas and the involvement of GABAergic signaling on ESI effects. CCI rats had electrodes implanted in the left agranular posterior insular cortex (pIC), and mechanical sensitivity was evaluated before and after one or five daily consecutive ESIs (15 min each, 60 Hz, 210 μs, 1 V). Five ESIs (repetitive ESI) induced sustained mechanical antinociception from the first to the last behavioral assessment without interfering with locomotor activity. A marked increase in Fos immunoreactivity in pIC and a decrease in the anterior and mid-cingulate cortex, periaqueductal gray and hippocampus were noticed after five ESIs. The intrathecal administration of the GABAA receptor antagonist bicuculline methiodide reversed the stimulation-induced antinociception after five ESIs. ESI increased GAD65 levels in pIC but did not interfere with GABA, glutamate or glycine levels. No changes in GFAP immunoreactivity were found in this work. Altogether, the results indicate the efficacy of repetitive ESI for the treatment of experimental neuropathic pain and suggest a potential influence of pIC in regulating pain pathways partially through modulating GABAergic signaling.

Anesthetic considerations and postoperative pain management in radical penectomy: Case report

Radical penectomy (RP) is infrequently performed as it is reserved for specific cases of penile cancer, hence the paucity of reports regarding surgical and anesthetic considerations. Acute postoperative pain, chronic post-surgical pain, concomitant mood disorders as well as a profound impact on the patient’s quality of life have been documented. This case is of a patient with diabetes and coronary heart disease, who presented with advanced, overinfected penile cancer, depressive disorder and a history of pain of neuropathic characteristics. The patient underwent radical penectomy using a combined spinal-epidural technique for anesthesia. Preoperatively, the patient was treated with pregabalin and magnesium sulphate, and later received a blood transfusion due to intraoperative blood loss. Adequate intra and postoperative analgesia was achieved with L-bupivacaine given through a peridural catheter during one week. Recovery was good, pain was stabilized to preoperative levels and the patient received pharmacological support and follow-up by psychiatry and the pain team.

Chronic continuous abdominal pain: evaluation of diagnostic features, iatrogenesis and drug treatments in a cohort of 103 patients

BACKGROUND

Chronic continuous abdominal pain (CCAP) is characteristic of centrally mediated gastrointestinal pain disorders. It consumes significant healthcare resources yet is poorly understood, with minimal cohort-specific data in the literature.

AIMS

To examine in a large cohort of CCAP patients, (a) diagnostic features, (b) iatrogenic impact of opioids and surgery, (c) drug treatment effects and tolerance.

METHODS

Consecutive tertiary CCAP referrals to a neurogastroenterology clinic (2009-2016) were reviewed for Rome IV and neuropathic pain criteria. Medical, surgical and drug histories, interventions and outcomes were correlated with clinical diagnosis and associated opioid use.

RESULTS

Of 103 CCAP patients (mean age 40 ± 14, 85% female), 50% had physiological exacerbations precluding full Rome IV Centrally Mediated Abdominal Pain Syndrome criteria. However, there were no significant differences between patients who satisfied Rome IV criteria and those who did not. Overall, 81% had allodynia (a nonpainful stimulus evoking pain sensation). Opioid use was associated with allodynia (P = 0.003). Prior surgery was associated with further operations post CCAP onset (P < 0.001). Although 68% had undergone surgical interventions, surgery did not resolve pain in any patient and worsened pain in 35%. Whilst duloxetine was the most effective neuromodulator (P = 0.003), combination therapy was superior to monotherapy (P = 0.007).

CONCLUSIONS

This is currently the largest cohort CCAP dataset that supports eliciting neuropathic features, including allodynia, for a positive clinical diagnosis, to guide treatment. Physiological exacerbation of CCAP may represent visceral allodynia, and need not preclude central origin. Use of centrally acting neuromodulators, and avoidance of detrimental opioids and surgical interventions appear to predict favourable outcomes.

The Role of the Peripheral Nerve Surgeon in the Treatment of Pain

Pain is a frequent cause of physician visits. Many physicians find these patients challenging because they often have complicated histories, emotional comorbidities, confusing examinations, difficult problems to fix, and the possibility of factitious complaints for attention or narcotic pain medications. As a result, many patients are lumped into the category of chronic, centralized pain and relegated to pain management. However, recent literature suggests that surgical management of carefully diagnosed generators of pain can greatly reduce patients' pain and narcotic requirements. This article reviews recent literature on surgical management of pain and four specific sources of chronic pain amenable to surgical treatment: painful neuroma, nerve compression, myofascial/musculoskeletal pain, and complex regional pain syndrome type II.

Chronic postsurgical pain: current evidence for prevention and management

Chronic postsurgical pain (CPSP) is an unwanted adverse event in any operation. It leads to functional limitations and psychological trauma for patients, and leaves the operative team with feelings of failure and humiliation. Therefore, it is crucial that preventive strategies for CPSP are considered in high-risk operations. Various techniques have been implemented to reduce the risk with variable success. Identifying the risk factors for each patient and applying a timely preventive strategy may help patients avoid the distress of chronic pain. The preventive strategies include modification of the surgical technique, good pain control throughout the perioperative period, and preoperative psychological intervention focusing on the psychosocial and cognitive risk factors. Appropriate management of CPSP patients is also necessary to reduce their suffering. CPSP usually has a neuropathic pain component; therefore, the current recommendations are based on data on chronic neuropathic pain. Hence, voltage-dependent calcium channel antagonists, antidepressants, topical lidocaine and topical capsaicin are the main pharmacological treatments. Paracetamol, NSAIDs and weak opioids can be used according to symptom severity, but strong opioids should be used with great caution and are not recommended. Other drugs that may be helpful are ketamine, clonidine, and intravenous lidocaine infusion. For patients with failed pharmacological treatment, consideration should be given to pain interventions; examples include transcutaneous electrical nerve stimulation, botulinum toxin injections, pulsed radiofrequency, nerve blocks, nerve ablation, neuromodulation and surgical management. Physical therapy, cognitive behavioral therapy and lifestyle modifications are also useful for relieving the pain and distress experienced by CPSP patients.

Neuropathic pain after sarcoma surgery: Prevalence and predisposing factors

Surgery for sarcoma frequently causes nerve damage as the dissection often violates the internervous plane. Nerve damage may cause neuropathic pain (NP), which can result in persistent pain after surgery. This is the first study to investigate the prevalence and associated factors of postoperative NP in patients who underwent surgery for sarcoma of the extremities or pelvis.Patients (n = 144) who underwent curative surgery at least 6 months prior to the visit for histologically confirmed sarcoma were enrolled. The presence of NP was assessed by administering PainDetect, a widely used questionnaire for detecting NP. Patients with PainDetect scores ≥13 were considered to have NP. The possible factors that might be associated with the development of NP were investigated: patient characteristics, tumor characteristics, extent of surgery, and adjuvant therapy.Out of 144 patients, 36 patients (25%) had NP. Patients with NP had significantly worse visual analog scale score (P < .001), Toronto Extremity Salvage Score (P < .001), and Musculoskeletal Tumor Society Rating Scale score (P < .001) than patients without NP. Among the possible factors associated with NP, patients with NP were more likely to have undergone pelvic surgery (P = .002) and multiple surgeries (P = .014) than patients without NP. In logistic regression analysis, pelvic surgery (odds ratio = 5.05, P = .005) and multiple surgeries (odds ratio = 2.33, P = .038) were independent factors associated with NP after sarcoma surgery.This study suggests that the prevalence of NP after surgery for sarcoma is considerable. Surgery of the pelvis and multiple surgeries are predictive of postoperative persistent NP.

Antiallodynic and antihyperalgesic activities of zerumbone via the suppression of IL-1β, IL-6, and TNF-α in a mouse model of neuropathic pain

Background

Neuropathic pain is a debilitating condition that severely affects the quality of life for those with this pain condition, and treatment for pain relief is greatly sought-after. Zerumbone (Zer), a sesquiterpene compound isolated from the rhizomes of a Southeast Asian ginger plant, Zingiber zerumbet (L.) Roscoe ex Smith. (Zingiberaceae), showed antinociceptive and antiinflammatory properties when previously tested on models of nociception and inflammation.

Objective

This study investigated the effects of prophylactic administration of zerumbone on allodynia and hyperalgesia in a mouse model of chronic constriction injury (CCI)-induced neuropathic pain.

Methods

Intraperitoneal administration of Zer (5–50 mg/kg) from day 1 post-surgery was carried out to identify the onset and progression of the pain condition. Responses toward mechanical and cold allodynia, and mechanical and thermal hyperalgesia were assessed on days 3, 5, 7, 9, 11, and 14 post-surgery. Blood plasma and spinal cord levels of interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and IL-10 were screened using enzyme-linked immunosorbent assay on day 15.

Results

Zer (10 and 50 mg/kg) attenuated pain symptoms on all days of behavioral testing without any signs of sedation in the rotarod test. ED₅₀ values for mechanical allodynia, cold allodynia, thermal hyperalgesia, and mechanical hyperalgesia were 9.25, 9.507, 8.289, and 9.801 mg/kg, respectively. Blood plasma and spinal levels of IL-1β, IL-6, and tumor necrosis factor-α but not IL-10 were significantly (p<0.05) suppressed by zer treatment.

Discussion and conclusion

Zer exhibits its antiallodynic and antihyperalgesic properties via reduced sensitization at nociceptor neurons possibly through the suppression of inflammatory mediators. Zer may prove to be a novel and beneficial alternative for the management of neuropathic pain.

The 5% Lidocaine-Medicated Plaster: Its Inclusion in International Treatment Guidelines for Treating Localized Neuropathic Pain, and Clinical Evidence Supporting its Use

When peripheral neuropathic pain affects a specific, clearly demarcated area of the body, it may be described as localized neuropathic pain (LNP). Examples include postherpetic neuralgia and painful diabetic neuropathy, as well as post-surgical and post-traumatic pain. These conditions may respond to topical treatment, i.e., pharmaceutical agents acting locally on the peripheral nervous system, and the topical route offers advantages over systemic administration. Notably, only a small fraction of the dose reaches the systemic circulation, thereby reducing the risk of systemic adverse effects, drug–drug interactions and overdose. From the patient’s perspective, the analgesic agent is easily applied to the most painful area(s). The 5% lidocaine-medicated plaster has been used for several years to treat LNP and is registered in approximately 50 countries. Many clinical guidelines recommend this treatment modality as a first-line option for treating LNP, particularly in frail and/or elderly patients and those receiving multiple medications, because the benefit-to-risk ratios are far better than those of systemic analgesics. However, some guidelines make only a weak recommendation for its use. This paper considers the positioning of the 5% lidocaine-medicated plaster in international treatment guidelines and how they may be influenced by the specific criteria used in developing them, such as the methodology employed by randomized, placebo-controlled trials. It then examines the body of evidence supporting use of the plaster in some prevalent LNP conditions. Common themes that emerge from clinical studies are: (1) the excellent tolerability and safety of the plaster, which can increase patients’ adherence to treatment, (2) continued efficacy over long-term treatment, and (3) significant reduction in the size of the painful area. On this basis, it is felt that the 5% lidocaine-medicated plaster should be more strongly recommended for treating LNP, either as one component of a multimodal approach or as monotherapy.

Pain Examination and Diagnosis

Pain is a clinical challenge to health care providers who care for hand disorders. Pathologic pain that prevents recovery leads to dissatisfaction for both patients and providers. Despite pain being common, the root cause is often difficult to diagnose. This article reviews the examination and diagnostic tools that are helpful in identifying pathologic and neuropathic pain. This article provides tools to speed recognition of these processes to allow earlier intervention and better patient outcomes.

Prevalence of acute neuropathic pain after cancer surgery: A prospective study

Background and Aims:

Acute neuropathic pain (ANP) is an under-recognised and under-diagnosed condition and often difficult to treat. If left untreated, it may further transform into persistent post-operative chronic pain leading to a disability.

Aims:

This prospective study was undertaken on 300 patients to identify the prevalence of ANP in the post-operative period by using a neuropathic pain detection questionnaire tool.

Methods:

This is an open-label study in which patients with six different types of cancer surgeries (Thoracic, gastro-intestinal, gynae/urology, bone/soft-tissue, head and neck and breast subgroups-50 each) were included for painDETECT questionnaire tool on the 2^nd and 7^th day surgery.

Results:

This study found a 10% point prevalence of ANP. Analysis showed that 25 patients had ‘possible’ ANP, the maximum from urological cancer surgery (6) followed by thoracic surgery (5). Five patients were found to have ‘positive’ ANP including 2 groin node dissection, 2 hemipelvectomy and 1 oesophagectomy.

Conclusion:

Significant relationship between severity of post-operative pain was found with the occurrence of ANP in the post-operative period requiring a special attention to neuropathic pain assessment. Larger studies are required with longer follow-up to identify accurately the true prevalence and causative factors of ANP after surgery.

Can treatment success with 5% lidocaine medicated plaster be predicted in cancer pain with neuropathic components or trigeminal neuropathic pain?

An expert group of 40 pain specialists from 16 countries performed a first assessment of the value of predictors for treatment success with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain. Results were based on the retrospective analysis of 68 case reports (sent in by participants in the 4 weeks prior to the conference) and the practical experience of the experts. Lidocaine plaster treatment was mostly successful for surgery or chemotherapy-related cancer pain with neuropathic components. A dose reduction of systemic pain treatment was observed in at least 50% of all cancer pain patients using the plaster as adjunct treatment; the presence of allodynia, hyperalgesia or pain quality provided a potential but not definitively clear indication of treatment success. In trigeminal neuropathic pain, continuous pain, severe allodynia, hyperalgesia, or postherpetic neuralgia or trauma as the cause of orofacial neuropathic pain were perceived as potential predictors of treatment success with lidocaine plaster. In conclusion, these findings provide a first assessment of the likelihood of treatment benefits with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain and support conducting large, well-designed multicenter studies.

The journey to chronic pain: a grounded theory of older adults' experiences of pain associated with leg ulceration

This study aimed to develop a grounded theory to describe and explain the experience of pain and its impact, as reported by the individuals who had pain associated with chronic leg ulceration. The Strauss and Corbin grounded theory approach was used. In-depth interviews were undertaken with 11 people aged ≥ 65 years from Leeds in the north of England. All participants were cared for by home care nurses and had painful leg ulceration. The emergent grounded theory centered on a core category of "The journey to chronic pain." The theory suggested a trajectory consisting of three phases that the patient experiences, where the end result is a chronic pain syndrome. In phase 1, leg ulcer pain has predominantly acute nociceptive properties, and if this is not managed effectively, or ulcers do not heal, persistent pain may develop with both nociceptive and neuropathic properties (i.e., phase 2). If phase 2 pain is not managed effectively, patients may then develop refractory long-term pain (phase 3). Those who progress to phase 3 tend to experience negative consequences such as insomnia, depression, and suicidal ideation. Only when health care professionals understand and acknowledge the persistent and long-term nature of the pain in this patient group can the pain be managed effectively.

Topical pain management with the 5% lidocaine medicated plaster--a review

BACKGROUND

The topical 5% lidocaine medicated plaster is recommended as first-line treatment for localized peripheral neuropathic pain.

SCOPE

In order to provide an overview of the efficacy and safety of the lidocaine plaster in the treatment of different neuropathic pain conditions, all efficacy and safety studies (randomized, controlled, or open-label with well described methodology), case reports, and pharmacological studies on the lidocaine plaster retrieved from a PubMed literature research (1960-March 2012) plus additional references identified from retrieved articles were included.

FINDINGS

The lidocaine plaster is efficacious in the treatment of neuropathic pain symptoms associated with previous herpes zoster infection. Results from a large open-label controlled study suggest that the lidocaine plaster could be at least as effective as systemic pregabalin in the treatment of postherpetic neuralgia and painful diabetic polyneuropathy. Open-label studies indicate efficacy in the treatment of other localized neuropathic pain conditions, such as painful idiopathic sensory polyneuropathy, complex regional pain syndrome, carpal tunnel syndrome sequelae, postsurgical and posttraumatic pain. Quality of life markedly improved in a variety of neuropathic pain conditions and long-term treatment provided sustained relief in patients with neuropathic pain who are responsive to lidocaine plaster. The lidocaine plaster is usually well tolerated. The risk of systemic adverse events and pharmacokinetic interactions with concomitant medication is minimal owing to low systemic exposure.

CONCLUSIONS

Treatment of several, primarily neuropathic and mixed-pain conditions with the 5% lidocaine medicated plaster was found efficacious and safe. Further controlled studies, in particular where only small open-label studies or case reports are available, should be considered.

Inguinal hernia: aetiology, diagnosis, post-repair pain and compensation

BACKGROUND

Inguinal hernia compensation depends on aetiology, diagnosis and complications, particularly post-hernia pain. New studies in these three areas bring confusion to claims.

METHODS

A comprehensive research of the literature using Medline: in aetiology, in diagnoses, the use of ultrasound and/or other investigations, in chronic post-hernia pain and the understanding of the pathogenesis of hernia and post-hernia pain. Using the above data, a creation of a protocol for acceptance of compensation claim.

RESULTS

Although intra-abdominal pressure has been accepted for 200 years as a significant aetiological factor in inguinal hernia, tissue studies and prospective studies suggest an inevitability. In diagnosis, the clinical detection of a lump is the gold standard; investigations are not required. An ultrasonic detection of a hernia without clinical correlation does not require surgery. Post-hernia chronic pain is not singular to hernia, is now considered neuropathic pain and treatment is conservative.

CONCLUSIONS

The work scene is possibly an aggravating factor but not a prime aetiological factor. The diagnosis does not require ultrasound. Chronic pain is neuropathic. A protocol for claim acceptance is presented.

The effects of pre-emptive analgesia with bupivacaine on acute post-laminectomy pain

INTRODUCTION

This is a prospective, non-randomized, hospital-based, case-controlled, clinical trial to assess the efficacy of perineural infiltration with bupivacaine at the related neural root for acute pain relief after lumbar laminectomy.

METHOD

Fifty-one patients undergoing unilateral one spinal level (lumbar 4) hemi-partial laminectomy were included in the study. In 22 of the patients (Group 2), bupivacaine was infiltrated onto the neural root immediately after the exposure; the 29 patients in the control group (Group 1) were not infiltrated. All patients were monitored post-operatively regarding pain determination using a visual analog scale, and the exact time of analgesic requirement during the first post-operative day was noted. Total analgesic dose given during the first post-operative day was also recorded.

RESULTS

The patients who received bupivacaine infiltration intraoperatively onto the neural root (Group 2) had a statistically significantly longer time to first analgesia request (P < 0.001) and also required significantly less analgesic when compared to the control group (Group 1) (P < 0.001). Perineural bupivacaine infiltration extended the early post-operative analgesic period. While the pain was not completely suppressed, the bupivacaine infiltration helped to manage the post-operative pain more effectively.

CONCLUSION

Our data suggests that pre-emptive analgesia via perineural infiltration of bupivacaine is a simple, and effective method for post-operative acute pain relief.

Management of neuropathic pain after surgical and non-surgical trauma with lidocaine 5% patches: study of 40 consecutive cases

OBJECTIVE

To determine the efficacy of lidocaine 5% patches [Versatis, commercialised by Grünenthal GmbH, Aachen, Germany] in patients with PNCCP.

BACKGROUND

This study focuses on chronic pain states of a neuropathic nature, located at the scar or over a larger area of the skin around the scar. This post-operative/post-traumatic neuropathic chronic cutaneous pain (PNCCP) may be a side-effect of any incision of the skin in the context of a surgical procedure or a traumatic event.

RESEARCH DESIGN AND METHODS

A single-centre, open, non-randomised, prospective study was performed in a university hospital referral centre for patients with chronic neuropathic pain after surgical or non-surgical trauma. Forty consecutive patients with chronic PNCCP, a VAS score > or =5, a LANSS score > or =12, and a stable consumption of pain medication were prospectively evaluated. All patients were given lidocaine 5% patches, following a 12 h on/off schedule.

MAIN OUTCOME MEASURES

Visual analogue scale (VAS) and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scorings were performed pretreatment (day 0), on the 28th day (4 weeks), and after 84 days (12 weeks).

RESULTS

The mean pretreatment VAS score (VAS(0)) was 7.225 +/- 1.209, and the mean pretreatment LANSS score (LANSS(0)) was 18.60 +/- 2.610. The number of patients with a VAS score <5 at the latest follow-up (VAS(84)) was 21 (52.5%). Mean VAS(84) was 4.625 +/- 1.675. Seventeen patients (42.5%) had a LANSS score <12 at the latest follow-up. Overall mean LANSS(84) was 12.85 +/- 3.093.

CONCLUSION

Lidocaine 5% patches seem to be an effective treatment of post-surgical and post-traumatic pain. These results should be supported with randomised and placebo-controlled studies with larger sample sizes and longer follow-ups.

Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 February 2008 and 31 January 2009 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.