[Considerations concerning the perioperative use of metamizole]. / Überlegungen zum perioperativen Einsatz von Metamizol.

BACKGROUND: The non-opioid analgesic metamizole (dipyrone) is approved for the treatment of severe pain and is often used in the perioperative period. As it can cause agranulocytosis, a severe adverse event, its perioperative administration is controversially discussed. OBJECTIVE: Is there enough evidence for a high risk of metamizol-induced agranulocytosis (MIA)? What are the consequences of its perioperative use with respect to the risk profiles of alternative analgesics? MATERIAL AND METHODS: Rapid review of the literature on the risk of MIA and adverse effects of non-opioid analgesics. RESULTS: The incidence of MIA is estimated to be one case per million inhabitants per year. The risk seems low compared to other drugs associated with a risk of agranulocytosis, such as antithyroid drugs and ticlopidine. The risk profile of metamizole concerning hepatotoxicity, nephrotoxicity, bleeding and cardiovascular adverse effects is favorable compared to other non-opioid analgesics. None of the non-opioid analgesics are licensed to be administered intraoperatively. CONCLUSION: The perioperative use of metamizole is possible after a thorough evaluation of the indications as it provides good analgesia with a generally favorable side effect profile and is administered intravenously. The risk of agranulocytosis is small but needs to be mentioned during patient informed consent in order to optimize early recognition. Intraoperative administration aims at reducing the expected severe postoperative pain. A documentation and justification for the evaluation of the indications are recommended.

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.

[What does pain intensity mean from the patient perspective? : A qualitative study on the patient perspective of pain intensity as an outcome parameter in treatment evaluation and on the interpretability of pain intensity measurements]. / Was bedeutet Schmerzintensität aus Sicht der Patienten? : Eine qualitative Studie zur Patientenperspektive auf Schmerzstärke als Konstrukt in der Therapieevaluation und die Interpretierbarkeit der Schmerzstärkemessung.

BACKGROUND: Pain intensity (PI) is a common outcome parameter in effectiveness studies on interdisciplinary multimodal pain therapy (IMPT), despite the fact that IMPT highlights dealing with rather than reducing chronic pain. Moreover, the measurement of pain intensity as a highly subjective experience is problematic. Patient participation is absolutely essential to examine the relevance of PI as a criterion of treatment success as well as to select/develop suitable measurement methods. METHOD: A qualitative multicenter study was conducted using focus groups with 69 patients (18-77 years; 80% female) at four different IMPT centers in Germany to discuss pain intensity as a therapy outcome parameter in IMPT, as well as the interpretability and feasibility of common measurement methods. RESULTS: The discussions emphasized that PI is a relevant, but not the primary, outcome in IMPT for patients. Patients' statements also demonstrate that there are some problems in measuring PI, for instance with regard to pain attacks. CONCLUSIONS: The focus group discussions suggested that, due to the highly subjective nature of PI, as well as (verbal) inaccuracies and a lack of standardization in common instruments, the measurement of pain intensity is a challenging task. These limitations should be taken into account in future studies.

[Psychological prophylaxis training for coping with postoperative pain. Long-term effects]. / Psychologisches Prophylaxetraining zur Bewältigung postoperativer Schmerzen. Langfristige Effekte.

INTRODUCTION: The present study was performed to investigate the effect of multidimensional psychological prophylaxis training focusing on coping with cognitive-emotional pain on recovery within the first 12 months after surgery. The training included the following three components: (1) education about pain, analgesia and psychological aspects of coping with pain, (2) training for coping with pain and (3) body-centered relaxation. MATERIAL AND METHODS: In the study 48 young male patients (surgical correction of a chest malformation) were assessed 1 day before surgery, at discharge and 3, 6 and 12 months postoperatively concerning postoperative pain intensity and pain disability as well as pain anxiety, pain catastrophizing and pain hypervigilance. Additionally, 24 of these patients received training on cognitive-emotional coping with pain 1 day before surgery and 1-3 days after surgery (each session 1 h). RESULTS: The proportion of patients with clinically relevant improvement was significantly higher in the training group compared to the control group. This was the case for acute pain intensity (approximately 1 week after surgery), pain disability 3 months later and pain anxiety 12 months after surgery. CONCLUSION: The resurgence of pain anxiety after 12 months could only be found in the control group and could be due to the upcoming surgical removal of the transsternal metal implant. The prophylaxis training can therefore be seen as a protective factor for long-term management of surgery-related consequences and future pain experiences.

[Update on preemptive analgesia : options and limits of preoperative pain therapy]. / Update zur präemptiven Analgesie : Möglichkeiten und Grenzen der präoperativen Schmerztherapie.

BACKGROUND: Wall created the term preemptive analgesia in 1988 and in doing so set in motion a movement to prevent acute and chronic postsurgical pain. The concept of preemptive analgesia implies the administration of analgesic drugs or an intervention before a surgical procedure. A preemptive analgesic approach can comprise non-steroidal anti-inflammatory drugs (NSAID) and cyclo-oxygenase-2 inhibitors (coxibs) used to decrease the production of prostaglandins, local anesthetics (e.g. epidural) to reduce nociceptive input to the spinal cord as well as opioids, N-methyl-D-aspartate (NMDA) antagonists, antidepressants and anticonvulsants, all of which have an inhibitory influence on the central nervous system. AIM: The aim of this article is to present the current possibilities and limits of preoperative pain therapy. MATERIAL AND METHODS: Since 2002 several meta-analyses on the effectiveness of preemptive analgesia have been published which came to varying conclusions on the supportive use of preemptive analgesia. The S3 guidelines on current perioperative pain management developed by the German Interdisciplinary Association for Pain Management (DIVS) specify the preemptive analgesic interventions found to be effective and will be discussed in detail in this article. Furthermore, the results of a current meta-analysis which follows the principle of preventive analgesia will be presented and which have not yet been considered in the S3 guidelines. RESULTS: Preemptive analgesia can reduce acute postoperative pain; however, minimizing the development of chronic pain conditions can only be successful in combination with intraoperative and postoperative pain therapy as well as social and psychological support when indicated (preventive analgesia). CONCLUSION: Reduction of chronic postoperative pain is an important medical function which is also justified from socioeconomic perspectives. Future studies should combine several procedures for perioperative pain therapy in order to do justice to the multifactorial aspects of pain chronification and should also be planned over a sufficiently long observation time period.

[Multidisciplinary assessment for multimodal pain therapy. Indications and range of performance]. / Interdisziplinäres Assessment zur multimodalen Schmerztherapie. Indikation und Leistungsumfang.

According to evidence-based German national guidelines for non-specific low back pain, a broad multidisciplinary assessment is indicated after persisting pain experience of 6 weeks in order to check the indications for an multi- and interdisciplinary pain therapy program. In this paper the necessary topics, the content and the disciplines involved as well as the extent of the multidisciplinary assessment are described as developed by the ad hoc commission on multimodal pain therapy of the German Pain Society.

[Structure and process quality of multimodal pain therapy. Results of a survey of pain therapy clinics]. / Struktur- und Prozessqualität multimodaler Schmerztherapie. Ergebnisse einer Befragung von schmerztherapeutischen Einrichtungen.

Multimodal therapy has demonstrated good clinical effectiveness in the treatment of chronic pain syndromes. However, within the German health system a comprehensive and nationwide access to multimodal therapy is not available and further improvement is therefore necessary. In order to analyze the current status of multimodal therapy and specifically its structural and procedural requirements and qualities, a survey was carried out in 37 pain clinics with established multimodal treatment programs. An anonymous questionnaire was used for data collection. Results demonstrated that a substantial accordance was found between all pain clinics concerning requirements for space, facilities and staff. Structured multidisciplinary assessments were carried out by all pain clinics even though the amount of time allocated for this varied widely. The main focus of multimodal therapy in all facilities was based on a common philosophy with a cognitive-behavioral approach to reduce patient helplessness and avoidance behavior and to increase physical and psychosocial activities as well as to strengthen self-efficacy. Some differences in the ways and means to achieve these goals could be demonstrated in the various programs.

Rhythmic pattern of PCA opioid demand in adults with cancer pain.

INTRODUCTION: Patient-controlled analgesia (PCA) has an established role in managing postoperative pain and has been successfully used in-patients with cancer pain. The variation of opioid requirement over a 24h period for patients with cancer pain is debated with suggestions of reduced need over night. METHODS: Retrospective review of 10years (1997-2006) data of all in-patients with cancer pain treated with strong opioids delivered by PCA. RESULTS: 141 patients with cancer pain had a mean cumulative 10day morphine equivalent dose per patient of 671mg (median 470mg; range 10-2170mg). At night (10:01pm to 06:00am) the patient's self administered less bolus doses (69mg, (25%)) than during the other two 8h periods (06:01am to 02:00pm, 91mg (33%) and 02:01pm to 10:00pm, 116mg (42%)). In 8 out of 10days a significant variation in bolus requests was observed with significantly less bolus requests during the night (Friedman test, p<0.05). Furthermore, the median number of delivered bolus requests per patient, at night, was 2-3 compared to the morning and afternoon periods of 3-7 and 3.5-6, respectively. CONCLUSION: PCA met individual patient's opioid needs in a safe and effective manner despite a large inter-individual variability in opioid consumption. Moreover, the study indicated a pattern of less opioid requirement at night.

[Multimodal pain therapy: principles and indications]. / Multimodale Schmerztherapie: Konzepte und Indikation.

Multimodal pain therapy describes an integrated multidisciplinary treatment in small groups with a closely coordinated therapeutical approach. Somatic and psychotherapeutic procedures cooperate with physical and psychological training programs. For chronic pain syndromes with complex somatic, psychological and social consequences, a therapeutic intensity of at least 100 hours is recommended. Under these conditions multimodal pain therapy has proven to be more effective than other kinds of treatment. If monodisciplinary and/or outpatient therapies fail, health insurance holders have a legitimate claim to this form of therapy.Medical indications are given for patients with chronic pain syndromes, but also if there is an elevated risk of chronic pain in the early stadium of the disease and aiming at delaying the process of chronification. Relative contraindications are a lack of motivation for behavioural change, severe mental disorders or psychopathologies and addiction problems. The availability of multimodal pain treatment centers in Germany is currently insufficient.

[Circadian rhythm of PCA-based opioid consumption in children with chemotherapy-related mucositis]. / Zirkadianer Rhythmus des PCA-gesteuerten Opioidverbrauchs bei Kindern mit chemotherapiebedingter Mukositis.

BACKGROUND: In order to match the interindividual and intraindividual differences in opioid requirements of pediatric oncology patients with mucositis, patient-controlled analgesia (PCA) seems to be the optimal pain therapy option, but scientific data are lacking. METHOD: A retrospective chart review of PCA-treated children with mucositis was carried out over a 6-year period (2000-2006) at the university hospital for children in Erlangen. RESULTS: The median age of the patients was 12.6 years and they mainly suffered from forms of acute leukemia. Daily morphine equivalent dose (MED) requirements increased with the start of the PCA therapy from 14.5 mg/day to 18.7 mg/day (p=0.021; Wilcoxon test). Children required more opioids by bolus request during the night (10:01 p.m. to 06:00 a.m.; 6.28 mg; 13%) than during the other 8-hour intervals (06:01 a.m. to 02:00 p.m. and 02:01 p.m. to 10:00 p.m.; both 21.3 mg (43.5%) during the whole 10-day study period. In 8 out of 10 days there was a significant diurnal variation in opioid requirement with significantly lower requirement during the night (p<0.05 Friedman test). The median count of delivered and un-delivered bolus requests during the night was 0-1 and 0, respectively. CONCLUSION: PCA seems to be an ideal, dependable and feasible mode of analgesic administration for the individual titration of dose in children with chemotherapy-induced mucositis. This is expressed through the increase in daily self-administered opioid doses after starting PCA, the huge interindividual variability in opioid consumption and the rare event of an un-delivered bolus request during lock-out time. With the use of a background infusion, additional bolus requests are rare during the night.

[Multimodal group therapy for the elderly with chronic pain: concept and results in a before and after comparison]. / Multimodale Gruppentherapie bei Senioren mit chronischen Schmerzen : Konzept und Ergebnisse im Prä-post-Vergleich.

BACKGROUND: Multimodal pain therapy programs are increasingly being recommended as an effective treatment option also for elderly patients with chronic pain. However, data from Germany are limited. PATIENTS AND METHODS: A multimodal group program adapted to the specific needs of elderly pain patients over 70 years old (20 treatment days, over 10 weeks) was started in our pain clinic in June 2005. We evaluated clinical, psychometric and physical data at the beginning and at the end of the treatment program, and compared outcome results with a waiting list control group. RESULTS: A total of 24 patients (mean age 76.2+/-4.79 years) could be evaluated of which 21 patients suffered from musculoskeletal pain, 2 from neuropathic pain syndromes and 1 from headache. In the waiting-list control group 13 patients were included. There were no significant between-group differences regarding age, stages of chronification, pain intensity, duration of pain and pain diagnosis. CONCLUSIONS: A multimodal pain therapy program for elderly patients (over 70 years old) is an effective treatment option to reduce pain intensity and pain disability. Furthermore, life quality and physical performance improved. Long-term effects still have to be evaluated.

Challenging the equipotency calculation for transdermal buprenorphine: four case studies.

AIMS: Opioids produce analgesia via different pain pathways. The aim of these case studies was to address the issue of opioid rotation or switching, raising the important issue of conversion ratios between different compounds and routes of administration. RESULTS: We present two cases of neuropathic pain and two cases of nociceptive pain with a significant neuropathic component, which were successfully treated with transdermal buprenorphine after the failure of other opioids. CONCLUSION: In each case, effective pain relief was produced by a lower dose than the proposed equipotency ratio of 1:75 would indicate, suggesting that a ratio of 1:110 to 1:115 may be more appropriate.

[Patient-controlled analgesia (PCA) in outpatients with cancer pain. Analysis of 1,692 treatment days]. / Patientenkontrollierte Analgesie (PCA) bei ambulanten Tumorschmerzpatienten. Analyse von 1692 Behandlungstagen.

INTRODUCTION: In the home-care setting, cancer pain patients in need of parenteral analgesia have to be switched to patient-controlled analgesia using portable pumps. But there is a paucity on data on the logistic requirements or the success rate of such a cost-intensive therapy performed by specialized home-care services. METHODS: In a retrospective study we analyzed data on care intensity, logistics and outcome of 46 consecutive palliative cancer patients with patient-controlled analgesia (PCA) in a home-care setting. RESULTS: On days 1, 2, and 3 of PCA the switch to parenteral analgesia resulted in a significant increase of the median daily opioid dose in comparison to the dose just prior to PCA. Concurrently, pain scores were significantly reduced. The median duration of PCA was 25 days (range 2-189 days). On average, each patient was seen by the home-care team every 7.4 days. The median duration of the home visits was 60 min (range, 10-190 min). Of the visits 20% were unscheduled, most of these visits being due to problems regarding analgesia. Most patients died at home. Insufficient analgesia required prefinal hospitalization in only a single case. CONCLUSION: If the indications are correct, intravenous PCA for palliative cancer pain patients results in higher opioid consumption and better pain control. Home-care PCA requires a lot of human and financial resources, but pain-related hospitalization can be prevented.

The superficial cervical plexus block for postoperative pain therapy in carotid artery surgery. A prospective randomised controlled trial.

OBJECTIVES: Rapid and reliable neurological evaluation soon after carotid artery surgery is feasible with modern methods of general anesthesia, but postoperative pain therapy remains a challenge. Use of opioids can mask neurological deficits. We investigated whether superficial cervical plexus block reduced postoperative opioid consumption after carotid endarterectomy. DESIGN: Prospective, randomised, double-blinded, placebo controlled trial. METHODS: 46 patients undergoing unilateral carotid endarterectomy under general anesthesia were randomized to either superficial cervical block with ropivacaine (n=23) or placebo (n=23). A patient controlled analgesia device (PCA) delivering morphine was provided for all patients. Subjective pain levels (visual analog scale, VAS) were recorded. The primary outcome was total morphine consumption on discharge from the recovery room. Secondary outcomes included arterial pCO2 (as an indicator of central nervous effects of morphine) and patient satisfaction. RESULTS: No adverse effects of the superficial cervical plexus block were reported. Four patients in the placebo group were excluded because of other drug use post-operatively. Per protocol analysis compared 23 patients in ropivacaine group and 19 patients in the placebo group. The ropivacaine group had a significant reduction in morphine consumption (3.8+/-2.0 versus 12.9+/-4.0, p<0.001), lower maximal pain scores (2.6+/-2.0 versus 5.8+/-1.6, p<0.001), and paCO2 levels (39.0+/-2.6 versus 41.9+/-3.4, p=0.008) at discharge from the recovery room. Patient satisfaction (1=very good to 6=insufficient) was substantially higher in the ropivacaine group (1.7+/-0.7 versus 3.1+/-1.2, p<00.01). CONCLUSION: The significant and clinically relevant lower morphine consumption and pain score, as well as the substantially higher patient satisfaction demonstrate that superficial cervical plexus block provides effective pain relief for patients undergoing carotid endarterectomy.

[Long-term pediatric opioid based pain control. Case reports]. / Opioidtherapie chronischer Schmerzen bei Kindern. Fallbesprechungen.

Based on 4 case reports we focus on the peculiarities of long-term pediatric opioid based pain control. Case report #1, emphasizing the importance of adequate opioid dosing with reference to body weight, illustrates that with adequate management oral sustained-release opioid therapy is safe even in infants less than one year old. Case report #2 is the first report on the usage of buccal fentanyl citrate for pediatric break-through pain control. Case report #3 focuses on the adverse effects of opioid pain control in an infant with neurological impairment. Case report #4 reports on the successful tumor pain control using transdermal buprenorphine. We conclude that proven therapeutic strategies for opioid pain control as applied in adults may be adopted for the usage on children in pediatrics. However, it is mandatory to take into account both the pharmacokinetic and pharmacodynamic peculiarities of childhood.

[Pain experience and pain therapy of tumor patients in the view of general practitioners]. / Schmerzerleben und Schmerzbehandlung von Tumorpatienten aus der Sicht von Allgemeinmedizinern.

AIM: The aim of the study presented in this paper is to find out how general practitioners evaluate their cancer patients' health, quality of life and type and extent of pain. In addition the study aims to get information about the training in pain therapy and palliative medicine. METHODS: A representative sample of 440 of all Austrian general practitioners was interviewed via a standardized questionnaire. The consent for the questioning had been obtained by telephone. RESULTS: The state of health and quality of life of the treated cancer patients are described as little satisfying and most unfavourably affected by the disease. The physicians suppose that the patients experience pain more intense than could be expected of them as endurable. Nevertheless the cancer patients appreciate pain therapy. CONCLUSION: As a result the medical training in pain therapy and palliative medicine should be improved. At the same time the future general practitioners should gain psychological competences, which would consequently provide them with a broad spectrum of treatment needed when dealing with pain patients (suffering from cancer).

[Topical application of morphine gel in inflammatory mucosal and cutaneous lesions]. / Topische Applikation von Morphingel bei entzündlichen Haut- und Schleimhautläsionen.

AIM: The aim of this study was to demonstrate a peripheral local opioid effect using case examples involving inflammatory mucosal and cutaneous lesions. METHODS: A 0.1% morphine gel, mixed in the hospital pharmacy, was applied several times daily to inflammatory mucosal lesions (oral, anogenital and in one patient to a skin ulcer). The effects and side effects were documented. RESULT: All patients experienced a significant reduction in pain with the use of topical morphine gel and no side effects were seen. CONCLUSION: Topical peripheral application of morphine gel is a simple, effective method that can be carried out by patients several times a day with few side effects.

[Differentiation of peripheral and central hyperalgesic effects of systemic procaine]. / Differenzierung peripherer und zentraler antihyperalgetischer Effekte einer systemischen Procaindauerinfusion.

OBJECTIVE: The aim of this study was to differentiate between the peripheral and central analgesic and antihyperalgesic properties of systemic procaine hydrochloride in standardized human pain models. METHOD: Subcutaneous injections of either 150 mg procaine hydrochloride or saline solution were administered at intervals of 2 weeks on a randomized and double blind basis. During the 90-min infusion and subsequent 60-min monitoring periods, touch sensitivity was determined and in addition two experimental hyperalgesic models were analyzed. RESULTS: While touch sensitivity was not affected by procaine hydrochloride, development of primary mechanical hyperalgesia was significantly reduced. CONCLUSION: The concentration of procaine hydrochloride used in our experiment elicited peripheral antihyperalgesic effects without central venous side effects. These results can account for the clinical effect of low-dose procaine hydrochloride in pain conditions exhibiting pronounced hyperalgesia.