Scandinavian Journal of Pain最新文献

Objectives: Pain assessment in anesthetized and non-communicative patients remains a challenge. Clinical signs such as tachycardia, hypertension, sweat and tears, have a low specificity for pain and should therefore ideally be replaced by more specific monitoring techniques. Skin conductance variability has been demonstrated to establish a patients' sensitivity to pain, but may be influenced by temperature changes that leads to profuse sweating. The aim of this pilot study was to test skin conductance changes during sudden temperature changes due to hyperthermic intraperitoneal chemotherapy (HIPEC) perfusation.

Methods: We investigated skin conductance algesimeter (SCA) in ten consecutive patients undergoing cytoreductive surgery and HIPEC. Results from the SCA was compared to other standard physiological variables at seven time points during the surgical procedure, in particular during the period with hyperthermic intraabdominal perfusion leading to an increase in the patients core temperature.

Results: Nine out of ten patients had an increase in the SCA measurements during the HIPEC phase correlating the increase in temperature.

Conclusion: SCA is unreliable to detect increased pain sensation during sudden perioperative temperature changes in adult patients.

Introduction: Pain is a common comorbidity in patients with hemophilia (PwH) due to hemophilic arthropathy. This study aims to explore pain sensitivity in PwH methodologically investigating in cuff pressure testing compared to algometer testing.

Methods: 37 PwH and 35 healthy control subjects (Con) enrolled in this study. Joint health status was assessed. Subjective pain was evaluated using numeric rating scales. Pain sensitivity was measured with pressure algometry and cuff pressure algometry. Pressure pain thresholds of the algometer (PPT_a) were measured at knee, ankle joints, and forehead. Subsequently, thresholds of cuff pressure were measured at the left and right lower legs (PPT_cuff). In both, lower values represent higher pain sensitivity.

Results: PwH exerted a worse joint health status than Con. Pain sensitivity was higher in PwH compared to Con as PPT_a of the knee and ankle joints were lower in PwH. No difference was observed in PPT_a at the forehead. Contrastingly, lower pain sensitivity was detected in PwH by higher PPT_cuff values compared to Con in both legs.

Conclusion: While PPT_a of the knee and ankle joints are lower in PwH, PPT_cuff are higher in PwH compared to Con. This reveals a paradox situation, highlighting that PwH experience local, joint- and hemophilic arthropathy-related pain, whereas pain sensitivity of non-affected soft tissue structures is lower. The reasons explaining the PPT_cuff results remain elusive but might be explained by coping strategies counteracting chronic joint pain, resulting in lower sensitivity at non-affected structures.

Objectives: Despite the fact that fibromyalgia, a widespread disease of the musculoskeletal system, has no specific treatment, patients have shown improvement after pharmacological intervention. Pregabalin has demonstrated efficacy; however, its adverse effects may reduce treatment adherence. In this context, neuromodulatory techniques such as transcranial direct current stimulation (tDCS) may be employed as a complementary pain-relieving method. Consequently, the purpose of this study was to evaluate the effect of pregabalin and tDCS treatments on the behavioral and biomarker parameters of rats submitted to a fibromyalgia-like model.

Methods: Forty adult male Wistar rats were divided into two groups: control and reserpine. Five days after the end of the administration of reserpine (1 mg/kg/3 days) to induce a fibromyalgia-like model, rats were randomly assigned to receive either vehicle or pregabalin (30 mg/kg) along with sham or active- tDCS treatments. The evaluated behavioral parameters included mechanical allodynia by von Frey test and anxiety-like behaviors by elevated plus-maze test (time spent in opened and closed arms, number of entries in opened and closed arms, protected head-dipping, unprotected head-dipping [NPHD], grooming, rearing, fecal boluses). The biomarker analysis (brain-derived neurotrophic factor [BDNF] and tumor necrosis factor-α [TNF-α]) was performed in brainstem and cerebral cortex and in serum.

Results: tDCS reversed the reduction in the mechanical nociceptive threshold and the decrease in the serum BDNF levels induced by the model of fibromyalgia; however, there was no effect of pregabalin in the mechanical threshold. There were no effects of pregabalin or tDCS found in TNF-α levels. The pain model induced an increase in grooming time and a decrease in NPHD and rearing; while tDCS reversed the increase in grooming, pregabalin reversed the decrease in NPHD.

Conclusions: tDCS was more effective than pregabalin in controlling nociception and anxiety-like behavior in a rat model-like fibromyalgia. Considering the translational aspect, our findings suggest that tDCS could be a potential non-pharmacological treatment for fibromyalgia.

Objectives: Perceived pain is a multi-factorial subjective variable, commonly measured by numeric rating scales, verbal descriptive scales (VDS), or by a position on an analogue line (VAS). A major question is whether an individual's VAS and VDS pain assessments, on the same occasion, could be comparable. The aim was to compare continuous and discretized VAS pain data with verbal descriptive pain datasets from the Oswestry Disability Index (ODI) and the European Quality of Life Scale (EQ-5D) in paired pain datasets.

Methods: The measurement level of data from any type of scale assessments is ordinal, having rank-invariant properties only. Non-parametric statistical methods were used. Two ways of discretizing the VAS-line to VAS-intervals to fit the number of the comparing VDS-categories were used: the commonly used (equidistant VAS,VDS)-pairs and the (unbiased VAS,VDS)-pairs of pain data. The comparability of the (VAS,VDS)-pairs of data of perceived pain was studied by the bivariate ranking approach. Hence, each pair will be regarded as ordered, disordered, or tied with respect to the other pairs of data. The percentage agreement, PA, the measures of disorder, D, and of order consistency, MA, were calculated. Total interchangeability requires PA = 1 and MA = 1.

Results: The wide range of overlapping of (VAS,VDS)-pairs indicated that the continuous VAS data were not comparable to any of the VDS pain datasets. The percentage of agreement, PA; in the (equidistant VAS,ODI) and (equidistant VAS, EQ-5D) pairs were 38 and 49%, and the order consistency, MA, was 0.70 and 0.80, respectively. Corresponding results for the (unbiased VAS,VDS)-pairs of pain data were PA: 54 and 100%, and MA: 0.77 and 1.0.

Conclusion: Our results confirmed that perceived pain is the individual's subjective experience, and possible scale-interchangeability is only study-specific. The pain experience is not possible to be measured univocally, but is possible for the individual to rate on a scale.

Objectives: Previous studies have suggested that experimental pain sensitivity is associated with cognitive function. The aim of this study is to assess this relationship in a large population-based sample.

Methods: We included 5,753 participants (aged 40-84 years) from the seventh wave of the population-based Tromsø Study who had been examined with cognitive tests and experimental pain assessments, and for whom information on covariates were available. Cox regression models were fitted using standardized scores on cognitive tests (12-word immediate recall test, digit symbol coding test, and Mini-Mental State Examination [MMS-E]) as the independent variable and cold pressor or cuff pressure pain tolerance as the dependent variables. Statistical adjustment was made for putative confounders, namely, age, sex, education, smoking, exercise, systolic blood pressure, body mass index, symptoms indicating anxiety or depression, analgesic use, and chronic pain.

Results: In multivariate analysis, cold pressor tolerance time was significantly associated with test scores on the 12-word immediate recall test (hazard ratio [HR] 0.93, 95% confidence interval [CI] 0.90-0.97, p < 0.001), the digit symbol coding test (HR 0.94, 95% CI 0.89-0.98, p = 0.004), and the MMS-E (HR 0.93, 95% CI 0.90-0.96 p < 0.001). Tolerance to cuff pressure algometry was significantly associated with 12-word immediate recall (HR 0.94-0.97, p < 0.001) and Digit Symbol Coding test scores (HR 0.93, 95% CI 0.89-0.96, p < 0.001) while there was no significant association with Mini Mental State Examination test score (HR 0.98, 95% CI 0.95-1.00, p = 0.082).

Conclusion: Lower pain tolerance was associated with poorer performance on cognitive tests.

Background: Studies on the concurrent validity of clinically applicable testing protocols for conditioned pain modulation (CPM) and temporal summation of pain (TSP) in breast cancer survivors (BCS) with persistent pain are lacking.

Objectives: This study investigated the concurrent validity of two bedside protocols for CPM and TSP in comparison to a respective reference protocol. The participants' preferences for bedside CPM and TSP protocols were assessed.

Methods: Thirty BCS experiencing persistent pain were included in this study. Each participant underwent a reference test along with two bedside alternatives for assessing both TSP and CPM. For CPM, a cold pressor test (CPT) and blood pressure cuff (BPC) were used as conditioning stimulus. The test stimulus was elicited in parallel by pressure pain threshold after 45 and 90 s of conditioning at the lower limb. The CPM reference test consisted of parallel heat stimuli at the forearms using a two-thermode system. TSP was elicited using a von Frey monofilament (256 mN) and an algometer (98 kPa) at the affected site and opposite lower limb. The TSP reference test consisted of heat stimuli at the affected site and opposite lower limb. Participants' testing preference was examined using a purpose-designed questionnaire. Spearman's rank test examined the correlation between protocols.

Results: The two bedside CPM protocols were strongly correlated (r = 0.787-0.939, p < 0.005). A strong correlation was found between the BPC protocol and reference test using the relative effect magnitude (r = 0.541-0.555, p < 0.005). The bedside TSP protocols were moderately correlated with each other only at the lower limb using absolute change scores (r = 0.455, p = 0.012). No significant correlation was found between the bedside and reference TSP protocols.

Conclusion: The significantly moderate to very strong correlations between the bedside protocols validate their interchangeability. Researchers and clinicians should be able to choose which bedside protocol they utilize; however, participants favored the use of a BPC and algometer for the evaluation of CPM and TSP, respectively.

Background: Low back pain (LBP) represents a worldwide burden with rising disability, especially in low- and middle-income countries. Indigenous Peoples are exposed to many risk factors for LBP and seem to have overall worse health and higher mortality compared to non-Indigenous. This article aims to provide a topical overview of LBP in Indigenous Peoples.

Methods: A comprehensive search was done using the keywords "Indigenous" and "back pain." Secondly, a cross-reference search of the citations list of the included articles was conducted.

Results: LBP is a prevalent, disabling health condition among Indigenous Peoples that impacts activities of daily living, emotional well-being, and cultural identity. Indigenous Peoples face numerous and unique barriers to obtain Western health care. LBP in Indigenous Peoples is partly iatrogenic and available health care lacks a culturally secure setting. In combination with racism and discrimination by health care providers, this leads to miscommunication, frustration, and poor outcome in Indigenous patients around the world.

Conclusion: Contextual considerations and interpretation of findings within the appropriate cultural context are needed in future research and treatment of LBP in Indigenous Peoples. However, our literature analysis exhibits disproportionate representation with the scarcity of studies of Indigenous Peoples of Asia and Africa. Addressing this gap in the literature could provide significant scientific value. Indigenous Peoples should not be forgotten in reducing the global burden for LBP.

Background and objectives: In Parkinson's disease (PD) patients, verbal suggestions have been shown to modulate motor and clinical outcomes in treatment with subthalamic deep brain stimulation (DBS). Furthermore, DBS may alleviate pain in PD. However, it is unknown if verbal suggestions influence DBS' effects on pain.

Methods: Twenty-four people with PD and DBS had stimulation downregulated (80-60 to 20%) and upregulated (from 20-60 to 80%) in a blinded manner on randomized test days: (1) with negative and positive suggestions of pain for down- and upregulation, respectively, and (2) with no suggestions to effect (control). Effects of DBS and verbal suggestions were assessed on ongoing and evoked pain (hypertonic saline injections) via 0-10 numerical rating scales along with motor symptoms, expectations, and blinding.

Results: Stimulation did not influence ongoing and evoked pain but influenced motor symptoms in the expected direction. Baseline and experimental pain measures showed no patterns in degree of pain. There was a trend toward negative suggestions increasing pain and positive suggestions decreasing pain. Results show significant differences in identical stimulation with negative vs positive suggestions (60% conditions AUC 38.75 vs 23.32, t(13) = 3.10, p < 0.001). Expectations to pain had small to moderate effects on evoked pain. Patients estimated stimulation level correctly within 10 points.

Conclusion: Stimulation does not seem to influence ongoing and evoked pain, but verbal suggestions may influence pain levels. Patients appear to be unblinded to stimulation level which is an important consideration for future studies testing DBS in an attempted blind fashion.

Objectives: The complexity of chronic pain requires interdisciplinary collaboration. Although this is recognisable in the framework for pain centres, few studies have investigated how interdisciplinary collaboration in pain centres is experienced by healthcare professionals, including the facilitators and barriers to interdisciplinary collaboration. The aim of the current study was therefore to investigate experiences of interdisciplinary collaboration in the treatment of patients with chronic pain among healthcare professionals in tertiary care pain centres.

Methods: Eleven healthcare professionals, representing different healthcare disciplines from the four regional pain centres in Norway, participated in semi-structured individual interviews. The data were analysed thematically.

Results: The results were categorised into three themes 'The best approach for chronic pain treatment', 'Collegial collaboration', and 'Challenges with interdisciplinary teamwork'. The informants valued the interdisciplinary work at the pain centre. They perceived it as the best approach for their patients and appreciated the support the collegial collaboration gave them as professionals. Although working together was rewarding and provided new insights, the informants also experienced the interdisciplinary teamwork as challenging, e.g., when the different professions disagreed on recommendations for further treatment or did not manage to work together as a team.

Conclusion: The informants found the interdisciplinary collaboration at the pain centre to provide the best treatment approach for their patients. It should be acknowledged that interdisciplinary teamwork can be challenging, and efforts should be put into establishing a good climate for collaboration and gaining knowledge about each profession's unique character and how they contribute to pain centre treatments.

Objectives: Appropriate administration of intraoperative analgesia is an essential factor in care and reasonable recovery times. Inappropriate intraoperative analgesia puts the patient at risk of acute postoperative pain (APOP). The absence of an objective standard for intraoperative nociceptive monitoring complicates pain care. Heart rate (HR) and mean arterial blood pressure (MABP) have been suggested as useful parameters during general anesthesia for nociceptive monitoring. However, studies focusing on whether intraoperative heart rate variability (HRv) and mean arterial blood pressure variability (MABPv) during general anesthesia can accurately monitor nociception in patients have remained inconclusive. The current study aimed to (1) identify the association of intraoperative heart rate and blood pressure variability in patients undergoing low-risk surgery with the incidence of APOP in the immediate postoperative setting and (2) evaluate the associations of clinical demographic factors with the incidence of APOP.

Methods: A retrospective observational cohort study was conducted. The outcome was moderate-to-severe APOP, defined as a numeric rating scale score of $\ge$ 4. HRv, MABPv, and potential confounders, such as age, body mass index, duration of surgery, smoking, depression, preoperative use of analgesics, and type of surgery, were used as independent variables.

Results: Data from 764 female oncological breast surgery patients were analyzed. No statistically significant association of HRv and MABPv with APOP was found. Lower age was associated with higher odds of APOP (odds ratio [OR] 0.978, p = 0.001). Increased length of surgery (OR 1.013, p = 0.022) and a history of depression were associated with increased odds of APOP (OR 2.327, p = 0.010). The subtype of surgery was statistically significantly associated with APOP (p = 0.006).

Conclusions: Our results suggest that heart rate and blood pressure variability intraoperatively, in female patients undergoing low-risk surgery, are not associated with, and thus not predictive of, APOP in the immediate postoperative setting.