Cryoneurolysis' outcome on pain experience (COPE) in patients with low-back pain: study protocol for a single-blinded randomized controlled trial.

BACKGROUND: Low-back pain, including facet joint pain, accounts for up to 20 % of all sick leaves in DenmarkA proposed treatment option is cryoneurolysis. This study aims to investigate the effect of cryoneurolysis in lumbar facet joint pain syndrome. METHODS: A single-center randomized controlled trial (RCT) is performed including 120 participants with chronic facet joint pain syndrome, referred to the Department of Neurosurgery, Aarhus University Hospital. Eligible patients receive a diagnostic anesthetic block, where a reduction of pain intensity ≥ 50 % on a numerical rating scale (NRS) is required to be enrolled. Participants are randomized into three groups to undergo either one treatment of cryoneurolysis, radiofrequency ablation or placebo. Fluoroscopy and sensory stimulation is used to identify the intended target nerve prior to administrating the above-mentioned treatments. All groups receive physiotherapy for 6 weeks, starting 4 weeks after treatment. The primary outcome is the patients' impression of change in pain after intervention (Patient Global Impression of Change (PGIC)) at 4 weeks follow-up, prior to physiotherapy. Secondary outcomes are a reduction in low-back pain intensity (numeric rating scale) and quality of life (EQ-5D, SF-36) and level of function (Oswestry Disability Index), psychological perception of pain (Pain Catastrophizing Scale) and depression status (Major Depression Inventory). Data will be assessed at baseline (T0), randomization (T1), day one (T2), 4 weeks (T3), 3 (T4), 6 (T5) and 12 months (T6). DISCUSSION: This study will provide information on the effectiveness of cryoneurolysis vs. the effectiveness of radiofrequency ablation or placebo for patients with facet joint pain, and help to establish whether cryoneurolysis should be implemented in clinical practice for this patient population. TRIAL REGISTRATION: The trial is approved by the ethical committee of Central Jutland Denmark with registration number 1-10-72-27-19 and the Danish Data Protection Agency with registration number 666,852. The study is registered at Clinicaltrial.gov with the ID number NCT04786145 .

Effect of simulation-based team training in airway management: a systematic review.

Major complications associated with airway management are rare but often have serious consequences. Complications frequently result from failures in communication and teamwork. We performed a systematic review on the effect of simulation-based team training on patient outcomes, healthcare professionals' clinical performance and preparedness for airway management. We included studies with simulation-based team training in airway management as the educational intervention, using any comparator, outcome and design. Two authors independently selected articles and assessed risk of bias using the Medical Education Research Study Quality Instrument and Newcastle-Ottawa Scale-Education. We screened 1248 titles and evaluated 116 full-text articles. Twenty-two studies were included. The Kirkpatrick model for evaluation of training was used to organise outcomes. Four studies reported patient-centred outcomes (Kirkpatrick level 4), and three studies' outcomes related to healthcare professionals' clinical performance (Kirkpatrick level 3). The results were ambiguous and the studies had significant methodological limitations, making it difficult to draw conclusions on the effect of simulation-based team training. To describe preparedness for airway management, we used outcomes related to participants' attitudes or perceptions and outcomes related to knowledge or skills demonstrated in a test setting (Kirkpatrick level 2). Most studies reporting these outcomes were in favour of simulation-based team training, but were prone to bias. We consider the current evidence to be weak and recommend that future research should be based on randomised study designs and patient-centred outcomes.

First-Principles Prediction of Surface Wetting.

We have developed a method for predicting the solvation contribution to solid-liquid interfacial tension (IFT) based on density functional theory and the implicit solvent model COSMO-RS. Our method can be used to predict wetting behavior for a solid surface in contact with two liquids. We benchmarked our method against measurements of contact angle from water-in-oil on silica wafers and a range of self-assembled monolayers (SAMs) with different compositions, ranging from oil-wet to water-wet. We also compared our predictions to literature data for wetting of a polydimethylsilane surface. By explicitly including deprotonation for silica surfaces and carboxylic acid SAMs, very good agreement was obtained with experimental data for nearly all surfaces. Poor agreement was found for amine-terminated SAMs, which could be the result of both method and model insufficiencies and impurities known to be present for such surfaces. Solid-liquid IFT cannot be measured directly, making predictions such as from our method all the more important.

A growth hormone receptor SNP promotes lung cancer by impairment of SOCS2-mediated degradation.

Both humans and mice lacking functional growth hormone (GH) receptors are known to be resistant to cancer. Further, autocrine GH has been reported to act as a cancer promoter. Here we present the first example of a variant of the GH receptor (GHR) associated with cancer promotion, in this case lung cancer. We show that the GHRP495T variant located in the receptor intracellular domain is able to prolong the GH signal in vitro using stably expressing mouse pro-B-cell and human lung cell lines. This is relevant because GH secretion is pulsatile, and extending the signal duration makes it resemble autocrine GH action. Signal duration for the activated GHR is primarily controlled by suppressor of cytokine signalling 2 (SOCS2), the substrate recognition component of the E3 protein ligase responsible for ubiquitinylation and degradation of the GHR. SOCS2 is induced by a GH pulse and we show that SOCS2 binding to the GHR is impaired by a threonine substitution at Pro 495. This results in decreased internalisation and degradation of the receptor evident in TIRF microscopy and by measurement of mature (surface) receptor expression. Mutational analysis showed that the residue at position 495 impairs SOCS2 binding only when a threonine is present, consistent with interference with the adjacent Thr494. The latter is key for SOCS2 binding, together with nearby Tyr487, which must be phosphorylated for SOCS2 binding. We also undertook nuclear magnetic resonance spectroscopy approach for structural comparison of the SOCS2 binding scaffold Ile455-Ser588, and concluded that this single substitution has altered the structure of the SOCS2 binding site. Importantly, we find that lung BEAS-2B cells expressing GHRP495T display increased expression of transcripts associated with tumour proliferation, epithelial-mesenchymal transition and metastases (TWIST1, SNAI2, EGFR, MYC and CCND1) at 2 h after a GH pulse. This is consistent with prolonged GH signalling acting to promote cancer progression in lung cancer.

Pain-related unscheduled contact with healthcare services after outpatient surgery.

This prospective, observational study explored the need for pain-related unscheduled contact with healthcare services after outpatient surgery. We hypothesised that 10% of outpatients would have pain-related unscheduled contact with healthcare services, and that the incidence would differ depending on the type of surgical procedure. In total, 905 patients who had undergone one of five common outpatient surgical procedures (knee or shoulder arthroscopy, surgical correction of hallux valgus, laparoscopic cholecystectomy or laparoscopic gynaecological procedures) completed an electronic questionnaire one week and eight weeks after surgery. Data from 732 patients (81%) were available for analysis. Within the first eight weeks after surgery, 150 patients (20.5%) had made unscheduled contact with healthcare professionals, in 247 cases due to pain that was most frequent in the first postoperative week. Risk factors were female sex, unemployment and laparoscopic cholecystectomy. The most frequent healthcare contact was with the general practitioner (46.4%), and the most frequent outcome was further information and guidance (41.2%). We have demonstrated that a minority of patients still needed to make contact with health services after outpatient surgery, most often due to inadequate pain management. This finding should be considered when planning postoperative monitoring and care, and developing postoperative patient education.

Functional and structural assessment of patients with and without persistent pain after thoracotomy.

BACKGROUND: Persistent pain is frequent after thoracotomy, with a reported prevalence of up to 60%. It remains unclear why some patients develop pain, whereas others do not. We therefore examined patients with and without pain after thoracotomy to identify pathophysiological contributors to persistent pain. METHODS: Twenty patients with persistent pain, 12 patients without pain and 20 healthy controls underwent detailed functional and structural assessment including psychometric and neuropathic pain questionnaires, bedside examination for pinprick hyperalgesia and brush allodynia, quantitative sensory testing according to the protocol of the German Research Network on Neuropathic Pain, measurement of capsaicin-evoked flare response, intradermal nerve density as determined by skin biopsies and laser- and heat-evoked potentials. RESULTS: Bedside testing revealed evoked pain in 16 of 20 patients with pain, but only in 2 of 12 patients without pain (p < 0.001). Quantitative sensory testing showed increased mechanical pain sensitivity (p = 0.018) on the operated side in patients with pain, but there were no differences between the two patient groups with regard to intradermal nerve fibre density, area and flux following capsaicin application and laser- and heat-evoked potentials. CONCLUSION: Different and individual pathophysiological mechanisms of pain may obscure the clinical picture and thus preclude identification of a specific pain profile in patients with persistent post-thoracotomy pain. SIGNIFICANCE: Evoked pain is more frequent in patients with pain. Assessment of intradermal nerve density, capsaicin-induced flare response and contact and laser heat-evoked potentials revealed no differences between pain patients and pain-free patients.

Gabapentin for post-operative pain management - a systematic review with meta-analyses and trial sequential analyses.

BACKGROUND: Perioperative pain treatment often consist of combinations of non-opioid and opioid analgesics, 'multimodal analgesia', in which gabapentin is currently used. The aim was to document beneficial and harmful effects of perioperative gabapentin treatment. METHODS: Randomized clinical trials comparing gabapentin vs. placebo or active placebo in adult surgical patients receiving gabapentin perioperatively were included. This review was conducted using Cochrane standards, trial sequential analysis (TSA), and Grading of Recommendations Assessment, Development, and Evaluation (GRADE). The primary outcomes were 24-h opioid consumption and incidence of serious adverse events (SAE). RESULTS: One hundred and thirty-two trials with 9498 patients were included. Thirteen trials with low risk of bias reported a reduction in 24-h opioid consumption of 3.1 mg [0.5, 5.6] [corrected]. In the analysis of gabapentin as add-on analgesic to another non-opioid analgesic regimen found a mean reduction in 24-h morphine consumption of 1.2 mg [-0.3, 2.6; TSA-adjusted CI: -0.3, 2.6] in trials with low risk of bias. [corrected]. Nine trials with low risk of bias reported a risk ratio of SAEs of 1.61 [0.91; 2.86; TSA-adjusted CI: 0.57, 4.57]. CONCLUSION: Based on GRADE assessment of the primary outcomes in trials with low risk of bias, the results are low or very low quality of evidence due to imprecision, inconsistency, and in some outcomes indirectness. Firm evidence for use of gabapentin is lacking as clinically relevant beneficial effect of gabapentin may be absent and harm is imminent, especially when added to multimodal analgesia.

Persistent pain is common 1 year after ankle and wrist fracture surgery: a register-based questionnaire study.

BACKGROUND: Substantial literature documents that persistent postsurgical pain is a possible outcome of many common surgical procedures. As fracture-related surgery implies a risk of developing neuropathic pain and complex regional pain syndrome (CRPS), further studies investigating the prevalence and pain characteristics are required. METHODS: All patients undergoing primary surgery because of ankle or wrist fracture at Hvidovre and Odense University Hospitals, Denmark, between April 15, 2013 and April 15, 2014, were identified from the Danish Fracture Database. A questionnaire regarding pain characteristics was sent to patients 1 yr after primary surgery. RESULTS: Replies were received from 328 patients, of whom 18.9% experienced persistent postsurgical pain defined as pain daily or constantly at a level that interfered much or very much with daily activities, 42.8% reported symptoms suggestive of neuropathic pain, and 4.0% fulfilled the diagnostic patient-reported research criteria for CRPS. CONCLUSIONS: Persistent postsurgical pain 1 yr after wrist and ankle fracture surgery is frequent, and a large proportion of patients experience symptoms suggestive of neuropathic pain and CRPS. Patients should be informed about the substantial risk of developing persistent postsurgical pain. Future studies investigating risk factors for persistent postsurgical pain that include both surgically and conservatively treated fractures are required.

Efficacy and safety of intravenous fentanyl administered by ambulance personnel.

BACKGROUND: Management of pain in the pre-hospital setting is often inadequate. In 2011, ambulance personnel were authorized to administer intravenous fentanyl in the Central Denmark Region. The aim of this study was to evaluate the efficacy and safety of intravenous fentanyl administered by ambulance personnel. METHODS: Pre-hospital medical charts from 2348 adults treated with intravenous fentanyl by ambulance personnel during a 6-month period were reviewed. The primary outcome was the change in pain intensity on a numeric rating scale (NRS) from before fentanyl treatment to hospital arrival. Secondary outcomes included the number of patients with reduction in pain intensity during transport (NRS ≥ 2), the number of patients with NRS > 3 at hospital arrival, and potential fentanyl-related side effects. RESULTS: Fentanyl reduced pain from before treatment (8, IQR 7-9) to hospital arrival (4, IQR 3-6) (NRS reduction: 3, IQR 2-5; P = 0.001), 79.3% of all patients had a reduction in > 2 on the NRS during transport, and 58.4% of patients experienced pain at hospital arrival (NRS > 3). Twenty-one patients (0.9%) had oxygen saturation < 90%. A decrease in Glasgow Coma Scale was seen in 31 patients (1.3%) and hypotension observed in 71 patients (3.0%). CONCLUSION: Intravenous fentanyl caused clinically meaningful pain reduction in most patients and was safe in the hands of ambulance personnel. Many patients had moderate to severe pain at hospital arrival. As the protocol allowed higher doses of fentanyl, feedback on effect and safety should be part of continuous education of ambulance personnel.

Pre-operative baroreflex sensitivity and efferent cardiac parasympathetic activity are correlated with post-operative pain.

BACKGROUND: A maladaptation of the autonomic nervous system may been seen in patients with chronic pain that includes persistent changes in the autonomic tone, increased heart rate, and reduced heart rate variability and baroreflex sensitivity. Baroreflex sensitivity and acute pain intensity have been reported to be inversely correlated. However, it is unknown whether the same correlation applies with regard to post-operative pain. In the present study, autonomic function was measured in patients scheduled for minor hand surgery and correlated with early and persistent pain after the procedure. Thus, the cause (autonomic imbalance) was present before the effect (post-operative pain). Our primary hypothesis was that a lower level of pre-operative baroreflex sensitivity is correlated with increased early post-operative pain. METHODS: There were 30 patients included and scheduled for open carpal tunnel surgery. Baroreflex sensitivity and heart rate variability were measured before surgery. Efferent cardiac parasympathetic activity was estimated by power spectral analysis of heart rate variability. Post-operative pain was recorded daily for 6 weeks (early post-operative pain) and for 1 week 1 year after surgery (persistent post-operative pain). RESULTS: Pre-operative baroreflex sensitivity correlated negatively with early (P=0.05) and persistent (P=0.04) post-operative pain. Efferent cardiac parasympathetic activity correlated negatively with early (P=0.03) but not persistent post-operative pain (P=0.12). CONCLUSIONS: The findings suggest that a low pre-operative level of baroreflex sensitivity is associated with higher post-operative pain intensity. To our knowledge, this is the first study to show the correlation between baroreflex sensitivity and post-operative pain.

Adverse effects of perioperative paracetamol, NSAIDs, glucocorticoids, gabapentinoids and their combinations: a topical review.

Post-operative pain affects millions of patients worldwide and the post-operative period has high rates of morbidity and mortality. Some of this morbidity may be related to analgesics. The aim of this review was to provide an update of current knowledge of adverse events (AE) associated with the most common perioperative non-opioid analgesics: paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids (GCCs), gabapentinoids and their combinations. The review is based on data from systematic reviews with meta-analyses of analgesic efficacy and/or adverse effects of perioperative non-opioid analgesics, and randomised trials and cohort/retrospective studies. Generally, data on AE are sparse and related to the immediate post-operative period. For paracetamol, the incidence of AEs appears trivial. Data are inconclusive regarding an association of NSAIDs with mortality, cardiovascular events, surgical bleeding and renal impairment. Anastomotic leakage may be associated with NSAID usage. No firm evidence exists for an association of NSAIDs with impaired bone healing. Single-dose GCCs were not significantly related to increased infection rates or delayed wound healing. Gabapentinoid treatment was associated with increased sedation, dizziness and visual disturbances, but the clinical relevance needs clarification. Importantly, data on AEs of combinations of the above analgesics are sparse and inconclusive. Despite the potential adverse events associated with the most commonly applied non-opioid analgesics, including their combinations, reporting of such events is sparse and confined to the immediate perioperative period. Knowledge of benefit and harm related to multimodal pain treatment is deficient and needs clarification in large trials with prolonged observation.

Post-operative analgesic effects of paracetamol, NSAIDs, glucocorticoids, gabapentinoids and their combinations: a topical review.

In contemporary post-operative pain management, patients are most often treated with combinations of non-opioid analgesics, to enhance pain relief and to reduce opioid requirements and opioid-related adverse effects. A diversity of combinations is currently employed in clinical practice, and no well-documented 'gold standards' exist. The aim of the present topical, narrative review is to provide an update of the evidence for post-operative analgesic efficacy with the most commonly used, systemic non-opioid drugs, paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs)/COX-2 antagonists, glucocorticoids, gabapentinoids, and combinations of these. The review is based on data from previous systematic reviews with meta-analyses, investigating effects of non-opioid analgesics on pain, opioid-requirements, and opioid-related adverse effects. Paracetamol, NSAIDs, COX-2 antagonists, and gabapentin reduced 24 h post-operative morphine requirements with 6.3 (95% confidence interval: 3.7 to 9.0) mg, 10.2 (8.7, 11.7) mg, 10.9 (9.1, 12.8) mg, and ≥ 13 mg, respectively, when administered as monotherapy. The opioid-sparing effect of glucocorticoids was less convincing, 2.33 (0.26, 4.39) mg morphine/24 h. Trials of pregabalin > 300 mg/day indicated a morphine-sparing effect of 13.4 (4, 22.8) mg morphine/24 h. Notably, though, the available evidence for additive or synergistic effects of most combination regimens was sparse or lacking. Paracetamol, NSAIDs, selective COX-2 antagonists, and gabapentin all seem to have well-documented, clinically relevant analgesic properties. The analgesic effects of glucocorticoids and pregabalin await further clarification. Combination regimens are sparsely documented and should be further investigated in future studies.

The suprasacral parallel shift vs lumbar plexus blockade with ultrasound guidance in healthy volunteers--a randomised controlled trial.

Surgical anaesthesia with haemodynamic stability and opioid-free analgesia in fragile patients can theoretically be provided with lumbosacral plexus blockade. We compared a novel ultrasound-guided suprasacral technique for blockade of the lumbar plexus and the lumbosacral trunk with ultrasound-guided blockade of the lumbar plexus. The objective was to investigate whether the suprasacral technique is equally effective for anaesthesia of the terminal lumbar plexus nerves compared with a lumbar plexus block, and more effective for anaesthesia of the lumbosacral trunk. Twenty volunteers were included in a randomised crossover trial comparing the new suprasacral with a lumbar plexus block. The primary outcome was sensory dermatome anaesthesia of L2-S1. Secondary outcomes were peri-neural analgesic spread estimated with magnetic resonance imaging, sensory blockade of dermatomes L2-S3, motor blockade, volunteer discomfort, arterial blood pressure change, block performance time, lidocaine pharmacokinetics and complications. Only one volunteer in the suprasacral group had sensory blockade of all dermatomes L2-S1. Epidural spread was verified by magnetic resonance imaging in seven of the 34 trials (two suprasacral and five lumbar plexus blocks). Success rates of the sensory and motor blockade were 88-100% for the major lumbar plexus nerves with the suprasacral technique, and 59-88% with the lumbar plexus block (p > 0.05). Success rate of motor blockade was 50% for the lumbosacral trunk with the suprasacral technique and zero with the lumbar plexus block (p < 0.05). Both techniques are effective for blockade of the terminal nerves of the lumbar plexus. The suprasacral parallel shift technique is 50% effective for blockade of the lumbosacral trunk.

Dexamethasone for pain after outpatient shoulder surgery: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Dexamethasone has analgesic properties when given intravenously before surgery, but the optimal dose has not been determined. We hypothesised that a dose of 40 mg dexamethasone would improve analgesia after outpatient shoulder surgery compared with 8 mg. METHODS: A randomised, double-blind, placebo-controlled clinical trial was conducted at Horsens Regional Hospital, Denmark. Patients scheduled for arthroscopic subacromial decompression and/or acromioclavicular joint resection as an outpatient procedure (n = 101) were randomised to receive intravenous dexamethasone 40 mg (D40), 8 mg (D8) or placebo (D0) before surgery. The primary outcome was pain intensity 8 h after surgery rated on a numeric rating scale of 0 to 10. Secondary outcomes were pain intensity, analgesic consumption and side effects during the first 3 days after surgery. RESULTS: Data from 73 patients were available for analysis: (D40: 25, D8: 26, D0: 22 patients). Eight hours after surgery, pain intensity were: [median (interquartile range)] group D40: 2 (1-4), group D8: 2.5 (1-5), group D0: 4 (2-7). There was no significant difference in pain intensity between group D40 and D8 after 8 h (P = 0.46) or at any other time. When comparing all three groups, a statistically significant dose-response relationship was seen for present, average and worst pain intensity after 8 h and on the following morning. No differences were found in analgesic consumption. No serious side effects were observed. CONCLUSION: Although our data supported a dose-response relationship, increasing the dexamethasone dose from 8 to 40 mg did not improve analgesia significantly after outpatient shoulder surgery.

Local infiltration analgesia for total knee arthroplasty: should ketorolac be added?

BACKGROUND: Adequate postoperative analgesia with minimal side-effects is essential for early mobilization and recovery in patients undergoing total knee arthroplasty (TKA). High-volume local infiltration analgesia (LIA) with ropivacaine has been introduced, but effects of adjuvants are still debated. We tested the hypothesis that the addition of ketorolac to LIA significantly improves analgesia after TKA. METHODS: Sixty patients undergoing TKA were randomized to receive intraoperative LIA (ropivacaine 300 mg and epinephrine 0.5 mg) combined with either ketorolac 30 mg (ketorolac group) or saline (control group). After surgery, eight bolus doses of ropivacaine 100 mg combined with either ketorolac 15 mg (ketorolac group) or saline (control group) were administered every 6 h via an intra-articular catheter. The primary outcome was postoperative consumption of i.v. morphine patient-controlled analgesia (PCA). Secondary outcomes were time to first request of i.v. morphine PCA, pain intensity, side-effects, and readiness for hospital discharge. RESULTS: Consumption of i.v. morphine PCA was lower in the ketorolac group vs control group {0-6 h: 0 (0-0) vs 5 (0-10) mg, P<0.0001; 0-48 h: 10 (0-22.5) vs 48.75 (30-82.5) mg, P<0.0001 [median (inter-quartile range, IQR)]}. Time to first request of i.v. morphine PCA was longer in the ketorolac group vs the control group [490 (248-617) vs 223 (115-319) min, P=0.02, median (IQR)]. Early postoperative pain (<48 h) and readiness for hospital discharge were also significantly reduced in the ketorolac group. CONCLUSIONS: LIA with ketorolac results in reduced morphine consumption, reduced pain intensity, and earlier readiness for hospital discharge.

Chronic pain after inguinal hernia repair in children.

BACKGROUND: The prevalence of moderate-to-severe pain after inguinal hernia repair (IHR) in adults is ≈ 10%. Two studies with very long follow-up periods (16.8 and 49 yr, respectively) have, however, suggested that the risk of developing chronic pain is much lower in children. The purpose of the present study was to examine the prevalence of chronic pain 6-48 months after IHR in children. METHODS: Postal questionnaires were sent to 156 children who had undergone IHR between the age of 6 months and 12 yr. The children were asked to recall the duration of postoperative pain, if necessary with help from their parents, and to describe the intensity and character of their pain, if the pain was still present. Children with chronic pain were offered quantitative sensory testing (QST), and a surgical examination, including ultrasound, in order to exclude hernia recurrence. RESULTS: Ninety-eight children, mean (sd) age 7.8 (2.6) yr, answered the questionnaire. Their age at the time of surgery was mean (sd) 4.6 (2.4) yr, and the follow-up period was mean (sd) 3.2 (1.3) yr. Five children (5.1%, 95% confidence interval: 0.75-9.5) had pain located in the inguinal region, and three of these children underwent further examination. There was no hernia recurrence, but QST revealed pinprick hyperalgesia and decreased pressure pain thresholds on the operated side in all three children. CONCLUSIONS: The prevalence of chronic pain after IHR in children is 5.1%, which is lower than the prevalence reported after adult hernia repair.

Mechanosensitivity before and after hysterectomy: a prospective study on the prediction of acute and chronic postoperative pain.

BACKGROUND: The incidence of chronic pain after hysterectomy is reported to be up to 30%, but the relative role of different pathogenic factors has not been defined. This study aimed to assess the predictive value of preoperative abdominal and vaginal mechanosensitivity for the subsequent development of acute and chronic pain after hysterectomy. METHODS: Ninety women undergoing hysterectomy for benign conditions were studied. Experimental testing was carried out on the day before hysterectomy, on the first postoperative day, and after 4 months. Abdominal testing included brush-evoked allodynia, pinprick hyperalgesia, wind-up-like pain, and pressure pain thresholds. Vaginal testing included pressure pain thresholds. The intensity of pelvic pain was recorded on a numerical rating scale before hysterectomy, daily in the first postoperative week, and after 4 months. RESULTS: The incidence of pelvic pain was 51% before hysterectomy and 17% after 4 months. Before hysterectomy, brush-evoked allodynia and pinprick hyperalgesia were more frequent in women with pelvic pain (P=0.04 and 0.02, respectively), with abdominal and vaginal pressure pain thresholds being lower in those with preoperative pelvic pain (P=0.04 and <0.01, respectively). Preoperative brush-evoked allodynia, pinprick hyperalgesia, and vaginal pressure pain threshold were associated with the intensity of acute postoperative pain (P=0.04, <0.01, and <0.01, respectively). Preoperative brush-evoked allodynia was also associated with pelvic pain after 4 months (P<0.01). CONCLUSIONS: Preoperative pain sensitization as reflected by cutaneous and vaginal hypersensitivity is associated with acute pain after hysterectomy, but less so with persistent pain.

Consequences of persistent pain after lung cancer surgery: a nationwide questionnaire study.

BACKGROUND: post-thoracotomy pain syndrome (PTPS) and its social consequences have been inconsistently investigated as most studies were either small sized, focused on a limited number of risk factors or included heterogeneous surgical procedures. The current objectives were to obtain detailed information on the consequences of PTPS after thoracotomy and video-assisted thoracic surgery (VATS) from homogenous unselected nationwide data, and to suggest mechanisms for the development of PTPS. METHODS: data from 1327 patients were collected using a prospective national database and combined with a detailed questionnaire. RESULTS: the response rate was 81.5%, resulting in 546 patients without prior thoracic surgery for the final analysis. Follow-up was 22 months (range 12-36). PTPS occurred in 33% thoracotomy patients and 25% VATS patients. Clinically relevant pain was present in 11-18% of the patients and severe pain in 4-12% depending on the level of physical activity. In PTPS patients, 64% also had pain from other locations on the body. Perceived sensory changes in the thoracic area were present in 63% of PTPS patients vs. 25% in pain-free patients (P<0.001). When comparing VATS with thoracotomy, no consistent differences in the prevalence, distribution of pain, sensory changes or effect of pain on daily activities were observed although clinically relevant and severe pain was reduced after VATS. CONCLUSIONS: this nationwide study corroborates that PTPS is a clinically relevant problem influencing daily activities a long time after thoracotomy and VATS. Nerve injury and increased pain responsiveness may explain the majority of symptoms, the prevalence and distribution of pain including perceived sensory sensations.

Chronic pain in adults after thoracotomy in childhood or youth.

BACKGROUND: Chronic pain is common after thoracotomy with reported prevalence rates of 20-60%. The pain may be caused by damage to the intercostal nerves during surgery. Some studies have suggested that young age at the time of surgery reduces the risk of developing chronic pain. So far, no studies have examined if children and adolescents develop chronic pain after thoracotomy. METHODS: Eighty-eight patients, mean (sd) age 39.3 (7.7) yr, who underwent thoracotomy between the age of 0 and 25 yr were asked to recall the duration of postoperative pain and-if pain was still present-to describe intensity and character of pain. In addition, all patients underwent quantitative sensory testing. RESULTS: Fourteen patients (16%) recalled that their postoperative pain had lasted for more than 3 months: one (3.2%) patient in the youngest group (0-6 yr), seven (19.4%) patients in the age group 7-12 yr, and six (28.5%) patients in the age group 13-25 yr (P=0.03). Three out of the 14 patients, who were 11, 11, and 18 yr of age at the time of surgery, still had pain at present. Quantitative sensory testing revealed hypo- and hyperphenomena in most patients, including those with persistent pain. Tactile detection thresholds and pressure detection thresholds were significantly higher on the operated side when compared with the contralateral side (n=88; P<0.001). CONCLUSIONS: The risk of developing chronic pain after thoracotomy seems to be lower if surgery is performed at a young age. Pain after thoracotomy is likely to be of neuropathic origin.

Oxycodone vs. fentanyl in the treatment of early post-operative pain after laparoscopic cholecystectomy: a randomised double-blind study.

BACKGROUND: It has been suggested that oxycodone is superior to other opioids in the treatment of visceral pain. We therefore compared the effect of intravenous (i.v.) oxycodone and i.v. fentanyl on post-operative abdominal (visceral) pain after outpatient laparoscopic cholecystectomy. METHODS: Seventy-eight patients were randomised to intra- and post-operative pain treatment with either oxycodone (n=39) or fentanyl (n=39). The patients received 10 mg oxycodone/100 microg fentanyl at the end of anaesthesia. In the post-anaesthetic care unit (PACU), 5 mg oxycodone/50 microg fentanyl was administered to patients with moderate pain [3-5 on a numeric rating scale (NRS)], and 10 mg oxycodone/100 microg fentanyl was administered to patients with severe pain (>5 on an NRS). The following measures were recorded: intensity of pain at arrival, after 30, 60 and 90 min and at discharge from the PACU; total consumption of oxycodone/fentanyl; nausea; vomiting; sedation and pressure tolerance thresholds. RESULTS: The median intra- and post-operative consumption of oxycodone was 15 mg (range: 10-40 mg) and the consumption of fentanyl was 200 microg (range: 100-500 microg). The intensity of abdominal pain was significantly lower in the oxycodone group at arrival (P<0.05), after 30, 60 and 90 min, and at discharge from the PACU (P<0.01). There was a strong tendency towards more side effects with oxycodone. CONCLUSIONS: Oxycodone provided better analgesia but also more side effects, suggesting that the doses used in the present study may not be equipotent.