Discogenic pain in acute nonspecific low-back pain

Acute nonspecific low-back pain is characterized by the sudden onset and severe unendurable low-back pain without radicular pain or neurological deficit in the lower extremities. The study was carried out using 55 patients who visited our hospital for acute nonspecific low-back pain, who exhibited degeneration on T2-weighted MR images, and underwent intradiscal injection of local anesthetics,steroid and contrast medium. Intervertebral disc sites with an obvious enhanced region in the posterior annulus of the disc on enhanced T1-weghted MR images was selected for intradiscal injection. When no enhaced region was detected, the most severely degenerated disc on T2-weighted MR images was selected. Acute nonspecific low-back pain with an improvement rate of 70% or higher 5min after injection was judged to be discogenic. The clinical characteristics and pathogenesis of discogenic acute nonspecific low-back pain were investigated. Forty of the 55 patients (73%) had discogenic acute nonspecific low-back pain. As for the characteristics of patients, the mean age was 37 years, and onset occurred upon casual daily movements in 18 patients (45%). Nineteen patients (48%) had bilateral low-back pain, and 29 patients (73%) had no tenderness in the paravertebral muscles. On plain X-ray radiograms, degeneration of the disc was normal or mild in 36 patients(91%). On the discograms, a radial tear extending to the posterior annulus was noted in all patients, but epidural leakage was seen only in six patients (15%). The degree of disc degeneration on T2-weighted MR images (Gibsons classification) was grade 3 in 30 patients (75%). Gadolinium-DTPA enhanced T1-weighted MR images showed an obvious enhanced region in the posterior annulus of the intervertebral disc in 19 patients (48%). As for the clinical characteristics of discogenic acute nonspecific low-back pain, the relatively young adult patients had no tenderness in the paravertebral muscles, and showed moderately degererated intervertebral discs. The pathogenesis of discogenic acute nonspecific low-back pain is mostly considered to be a re-rupture in an asymptomatic ruputured region in the posterior annulus, repaired by granulation tissue, in a moderately degenerated intervertebral disc with a radial tear.     

Paediatric chronic pain

Many children and adolescents experience chronic pain at some point in their childhood. While the majority may be successfully supported by their local services, some may develop persistent pain-related functional disability that should prompt referral to a multidisciplinary paediatric pain service for assessment. These teams work with the family to provide a framework for promoting rehabilitation and restoration of function based on the biopsychosocial model. Mental health difficulties including psychological trauma are often a significant factor. Individualized therapeutic work is core to the pain management pathway. Medications and therapeutic injections are used less frequently in children compared to adult practice but may have a role in facilitating rehabilitation as part of a multidisciplinary approach.     

From pain research to pain treatment: the role of human experimental pain models

There is no objective measure of a complete pain perception; we can, however, measure different aspects of nociceptive processing and pain perception. Earlier, experimental pain models often only involved induction of cutaneous pain using a single stimulus modality. Recently new experimental models have been developed eliciting various modalities of deep and visceral pain which more closely resemble clinical pain conditions. It is imperative to use multi-modal and multi-structure pain induction and assessment techniques, because a simple model cannot describe the very complex and multi-factorial aspects of clinical pain. Furthermore, it is important to assess pain under normal and pathophysiological conditions.The importance of peripheral and central hyperexcitability for acute and chronic pain has been demonstrated in animals and, to some extent, in humans. However, in spite of our immense knowledge, we still do not know how to prevent and treat this hyperexcitability efficiently. Our understanding of nociceptive mechanisms involved in acute and chronic pain and the effects of anaesthetic drugs or combinations of drugs on these mechanisms in humans may also be expanded using human experimental models. This mechanism-based approach may help us to develop and test therapeutic regimes in patients with acute and chronic pain.     

Interventional pain management for phantom limb pain: An algorithmic approach

Phantom limb pain is a type of chronic pain existing in different organs, not just limbs. The incidence is very high in the postamputation period and treatment can be a challenge. The pharmaceutical treatment strategies in addition to psychological rehabilitative strategies and interventional management play a successful role in the management of these patients. For this article, we conducted a review of literature about pain management for phantom limb pain to identify the treatment modalities, which involved interventional pain management, and an algorithmic approach is proposed.     

Management of acute pain

Acute pain is a common feature in the presentation of surgical and traumatic pathology and in postoperative patients. In pathological presentations acute pain may have a protective role serving as a warning sign, with muscle spasm helping to limit movement and prevent further injury. Acute postoperative pain can hinder recovery due to limited mobility and may lead to a range of complications, increasing patient morbidity and mortality. Timely and effective management of acute pain is therefore imperative. An acute pain service (APS) is able to assist in the management of complex patients and those with specific invasive analgesic interventions. However, the immediate prescribing is the responsibility of the admitting surgical doctor and therefore this article aims to give an overview of the considerations needed to ensure safe and effective management of acute pain.     

Breakthrough pain in opioid-treated chronic non-malignant pain patients referred to a multidisciplinary pain centre: a preliminary study

BACKGROUND: Breakthrough pain (BTP) has not formerly been discussed as such in chronic non-malignant pain patients referred to pain centres and clinics. The purpose of the study was to investigate the prevalence, characteristics and mechanisms of BTP in opioid-treated chronic non-malignant pain patients referred to a pain centre and to assess the short-term effects of pain treatment. METHODS: Patients were assessed at referral (T(0)) and after a treatment period of 3 months (T(3)) using the visual analogue scale (VAS) of the brief pain inventory (BPI) within somatic nociceptive, neuropathic and/or visceral pain conditions, the mini mental state examination (MMSE) and the hospital anxiety and depression scale (HADS). The main treatment intervention from T(0) to T(3) was to convert short-acting oral opioids to long-acting oral opioids and to discontinue on demand and parenteral use of opioids. RESULTS: Thirty-three patients were assessed at T(0) and 27 at T(3). The prevalence of BTP declined significantly from T(0) (90%) to T(3) (70.4%). Worst, least, average and current pain intensities as well as duration of BTP were significantly reduced from T(0) to T(3.) The majority of BTPs were exacerbation of background pain assumed to be of the same pain mechanisms. High average pain intensity (BPI) was significantly associated with high scores for both anxiety and depression (HADS). CONCLUSION: BTP in chronic non-malignant pain patients seems to be surprisingly frequent and severe. Stabilizing the opioid regimen seems to reduce pain intensity in general as well as the intensity and duration of BTP. Average pain intensity was associated with anxiety and depression.     

Persistent post-surgical pain and neuropathic pain after total knee replacement

AIM: To study the prevalence of persistent post-surgical pain (PPSP) and neuropathic pain (NP) after total knee replacement (TKR).METHODS: MEDLINE and Embase databases were searched for articles published until December 2014 in English language. Published articles were included if they referred to pain that lasts at least 3 mo after primary TKR for knee osteoarthritis, and measured pain with pain specific instruments. Studies that referred to pain caused by septic reasons and implant malalignment were excluded. Both prospective and retrospective studies were included and only 14 studies that match the inclusion criteria were selected for this review.RESULTS: The included studies were characterized by the heterogeneity on the scales used to measure pain and pre-operative factors related to PPSP and NP. The reported prevalence of PPSP and NP seems to be relatively high, but it varies among different studies. There is also evidence that the prevalence of post-surgical pain is related to the scale used for pain measurement. The prevalence of PPSP is ranging at 6 mo from 16% to 39% and at 12 mo from 13.1% to 23% and even 38% of the patients. The prevalence of NP at 6 mo post-operatively is ranging from 5.2% to 13%. Pre-operative factors related to the development of PPSP also differ, including emotional functioning, such as depression and pain catastrophizing, number of comorbidities, pain problems elsewhere and operations in knees with early grade of osteoarthritis.CONCLUSION: No firm conclusions can be reached regarding the prevalence of PPSP and NP and the related factors due to the heterogeneity of the studies.     

Improvement of burn pain management through routine pain monitoring and pain management protocol

Introduction

Pain management is an important aspect of burn management. We developed a routine pain monitoring system and pain management protocol for burn patients. The purpose of this study is to evaluate the effectiveness of our new pain management system.

Methods

From May 2011 to November 2011, the prospective study was performed with 107 burn patients. We performed control group (n = 58) data analysis and then developed the pain management protocol and monitoring system. Next, we applied our protocol to patients and performed protocol group (n = 49) data analysis, and compared this to control group data. Data analysis was performed using the Numeric Rating Scale (NRS) of background pain and procedural pain, Clinician-Administered PTSD Scale (CAPS), Hamilton Depression Rating Scale (HDRS), State-Trait Anxiety Inventory Scale (STAIS), and Holmes and Rahe Stress Scale (HRSS).

Results

The NRS of background pain for the protocol group was significantly decreased compared to the control group (2.8 ± 2.0 versus 3.9 ± 1.9), and the NRS of procedural pain of the protocol group was significantly decreased compared to the control group (4.8 ± 2.8 versus 3.7 ± 2.5). CAPS and HDRS were decreased in the protocol group, but did not have statistical significance. STAIS and HRSS were decreased in the protocol group, but only the STAIS had statistical significance.

Conclusion

Our new pain management system was effective in burn pain management. However, adequate pain management can only be accomplished by a continuous and thorough effort. Therefore, pain control protocol and pain monitoring systems need to be under constant revision and improvement using creative ideas and approaches.     

Paediatric chronic pain

Chronic pain in childhood is common and if untreated may lead to significant pain-related disability, emotional disturbance and poor school attendance. Many children and adolescents are successfully managed outside of specialist paediatric pain management clinics in a wide range of clinical settings. However, some children require the expertise of a multidisciplinary pain management team in a dedicated paediatric centre. Following multidisciplinary assessment an individualized pain management plan is agreed with the family. Treatment options can be classified into pharmacological, physical and psychological therapies. The aim of treatment is to facilitate a restoration of function for the child, working with the family as a whole.     

Cancer pain management

Pain occurs in more than 80% of cancer patients before death. Because of the increase in the frequency of cancer deaths worldwide, it is imperative to address cancer pain as a public health problem. Until recently, educational efforts were focused on treatment issues rather than adequate assessment. The approach to pain intensity as a multidimensional construct has helped in focusing treatments and identifying prognostic factors. Valid tools have been developed that allow multidisciplinary assessment of these prognostic factors and their complex interrelationship with the analgesic response. As a result of increased opioid exposure, patients are currently developing newer toxicities, mostly central excitability including delirium, myoclonus, grand mal seizures, and hyperalgesia. The observation that more than 80% of patients will require alternate routes for opioid delivery before death led to the development of a number of novel and effective alternate routes for delivery. Finally, in recent years it has become evident that some specific pain syndromes need to be addressed using specific assessment and management techniques. Incidental pain, somatization, neuropathic pain, and cancer pain in patients with alcoholism and drug addiction are some of these syndromes.     

Complex regional pain syndrome

Br J Anaesth 2001; 87: 99–106     

Chronic pain management after surgery

Chronic post-surgical pain is a common problem affecting between 2% and 10% of adults after surgery and a significant health burden. The development of chronic post-surgical pain involves multiple mechanisms including peripheral and central sensitization and nerve injury, thought to be the most significant factor. There are many risk factors including preoperative pain, chemotherapy/radiotherapy, surgical, psychological and genetic factors. The prevention of chronic post-surgical pain is challenging but progress is being made in identifying at risk groups, improved surgical technique and preventative analgesia including regional analgesia. Accurate diagnosis is essential for proper management, including identification of neuropathic pain. Management involves identifying any surgically or medically treatable cause, followed by pharmacological, psychological, physical and interventional management. It is essential for all clinicians involved in the care of surgical patients to have an awareness of chronic post-surgical pain, its prevention, diagnosis and treatment.     

白介素和神经病理性疼痛

近来实验发现免疫细胞活化对于人类和实验动物神经病理性疼痛的病因和症状有密切联系,而免疫细胞活化的一类产物--白介素在疼痛形成和维持过程中发挥重要作用.此文讨论白介素-1(白介素-1α、白介素-1β、白介素-1ra)、白介素-6和白介素-10在神经病理性疼痛的产生和维持过程的作用,探讨白介素在神经病理性疼痛治疗的前景.     

Chronic post-sternotomy pain

BACKGROUND: Chronic postoperative pain is a well-recognised problem. The incidence of severe incapacitating pain is about 3-5% after various types of surgery such as thoracotomy, repair of inguinal hernias and mastectomy. Sternotomy causes considerable postoperative pain and patients with chronic post-sternotomy pain are often referred to pain clinics. Epidemiological studies on chronic post-sternotomy pain are scarce, however. The aim of this paper was to study the incidence and possible risk factors of chronic pain following sternotomy operations performed for coronary bypass grafting or thymectomy. METHODS: Two groups of patients were studied for persistent pain following sternotomy operations. A questionnaire was sent in January 1997 to 71 patients with myasthenia gravis (MG) who had undergone a thymectomy during 1985-1996 and 720 patients who had had coronary bypass grafting (CABG) in 1994 were interviewed by letter. The patients were asked about the presence of pain and other symptoms in the chest, shoulders, arms or legs that they thought were connected to surgery. They were also asked about the quality of the pain and its evolvement with time. The patients' records were checked for details about surgery, anaesthesia and the state of the coronary disease. RESULTS: The response rate was 87%. The interval between the interview and surgery varied from 6 months to 12 years in the MG group and it was 2-3 years in the CABG group. In the MG group, 27% of the patients reported chronic post-sternotomy pain, which was moderate to severe in 48% of the patients. In the CABG group, 28% of the patients still had post-sternotomy pain, which was moderate to severe in 38% of patients. Of the patients who had post-sternotomy pain, one-third reported sleep disturbances due to the pain. CONCLUSION: Chronic post-sternotomy pain is an important complication that may have a significant impact on the patient's everyday life. Future studies will show whether minimising complications, improving postoperative care and starting early adequate pain management will reduce the incidence of this problem.     

Chronic pain management after surgery

Chronic post-surgical pain is a common problem affecting between 2% and 10% of adults after surgery and a significant health burden. The development of chronic post-surgical pain involves multiple mechanisms including peripheral and central sensitization and nerve injury, thought to be the most significant factor. There are many risk factors including preoperative pain, chemo/radiotherapy, surgical, psychological and genetic factors. The prevention of chronic post-surgical pain is challenging but progress is being made in identifying at-risk groups, improved surgical technique and preventative analgesia including regional analgesia. Accurate diagnosis is essential for proper management, including identification of neuropathic pain. Management involves identifying any surgically or medically treatable cause, followed by pharmacological, psychological, physical and interventional management. It is essential for all clinicians involved in the care of surgical patients to have an awareness of chronic post-surgical pain, its prevention, diagnosis and treatment.     

Chronic pain after surgery

Br J Anaesth 2001; 87: 88–98     

Prediction of post-operative pain by an electrical pain stimulus

BACKGROUND: Treatment of post-operative pain is still a significant problem. Recently, interest has focused on pre-operative identification of patients who may experience severe post-operative pain in order to offer a more aggressive analgesic treatment. The nociceptive stimulation methods have included heat injury and pressure algometry. A simple method, Pain Matcher (PM), using electrical stimulation, is validated for pain assessment, but has not been evaluated as a tool for prediction of post-operative pain. Our aim was to assess the predictive value of pre-caesarean section pain threshold on intensity of post-caesarean section pain using the PM. PATIENTS AND METHODS: Thirty-nine healthy women scheduled for elective caesarean section were studied. The anaesthetic/analgesic procedures included spinal anaesthesia, paracetamol, diclofenac, controlled-release (CR) oxycodone and morphine on request. Pre-operatively, the sensory and pain thresholds were measured using the PM. Post-operatively, a midwife, blinded for pre-caesarean pain threshold assessments, assessed the pain at rest and during mobilization every 12 h for 2 days. Consumption of analgesics was also recorded. RESULTS: Pre-operative pain threshold correlated significantly with post-caesarean pain score (VAS) at rest and mobilization: [Spearman's rho =-0.65 (-0.30 to -0.75), P < 0.01] and [Spearman's rho =-0.52 (-0.23 to -0.72), P < 0.01], respectively. There was no significant correlation between pre-operative PM assessment of sensory threshold and post-operative pain. CONCLUSION: Electrical pain threshold before caesarean section seems to predict the intensity of post-operative pain. This method may be used as a screening tool to identify patients at high risk of post-operative pain.     

Mechanisms of inflammatory pain

Br J Anaesth 2001; 87: 3–11     

Pathophysiology of pain

Pain is a major symptom of many different diseases. Modern pain research has uncovered important neuronal mechanisms that are underlying clinically relevant pain states, and research goes on to define different types of pains on the basis of their neuronal and molecular mechanisms. This review will briefly outline neuronal mechanisms of pathophysiological nociceptive pain resulting from inflammation and injury, and neuropathic pain resulting from nerve damage. Pain is the sensation that is specifically evoked by potential or actual noxious (i.e. tissue damaging) stimuli or by tissue injury. Pain research has not only explored the neuronal and molecular basis of the pain system of the healthy subject but has also provided insights into the function and plasticity of the pain system during clinically relevant pains such as post-injury pain, inflammatory pain, postoperative pain, cancer pain and neuropathic pain. This review will briefly describe the pain system and then address neuronal mechanisms that are involved in clinical pain states.