Abstract Objectives The purpose of this systematic review is to analyze the available literature on structural and functional brain abnormalities in chronic low back pain (CLBP) using several brain ...magnetic resonance imaging (MRI) techniques. Methods PubMed and Web of Science were systematically screened for relevant literature using different combinations of keywords regarding structural and functional brain imaging techniques in patients with CLBP. Reference lists of included articles were hand-searched for additional literature. Eligible articles were assessed on risk of bias and reviewed by two independent researchers. Results The search query returned 27 articles meeting the inclusion criteria. Methodological quality varied from poor to good. A total of 10 studies evaluated structural gray matter changes. There is conflicting evidence in global gray matter changes, with both increases and decreases shown in different studies. Gray matter changes were demonstrated in specific brain regions. Structural white matter changes were reported in five studies. There is conflicting evidence in total white matter volume due to both increases and unchanged white matter. Several regional differences were identified in which white matter changes were shown. Functional organization during rest was evaluated in 10 studies. CLBP patients showed increased activation in specific regions, together with a disrupted default mode network. A total of six studies evaluated brain activity in response to a nociceptive stimulus. Findings suggest that patients demonstrated increased activity in pain-related regions, and decreased activity in analgesic regions. Conclusions Overall, there is moderate evidence for regional changes in gray and white matter, together with an altered functional connectivity during rest and increased activity in pain-related areas following painful stimulation, evidencing an upregulated pain matrix. More longitudinal research is needed to clarify the temporal relationship regarding pain and neuroplastic changes, and integration of different brain imaging techniques is warranted.
Chronic pain after laparoscopic cholecystectomy is related to postoperative pain during the first postoperative week, but it is unknown which components of the early pain response is important. In ...this prospective study, 100 consecutive patients were examined preoperatively, 1 week postoperatively, and 3, 6, and 12 months postoperatively for pain, psychological factors, and signs of hypersensitivity. Overall pain, incisional pain (somatic pain component), deep abdominal pain (visceral pain component), and shoulder pain (referred pain component) were registered on a 100-mm visual analogue scale during the first postoperative week. Nine patients developed chronic unexplained pain 12 months postoperatively. In a multivariate analysis model, cumulated visceral pain during the first week and number of preoperative biliary pain attacks were identified as independent risk factors for unexplained chronic pain 12 months postoperatively. There were no consistent signs of hypersensitivity in the referred pain area either pre- or postoperatively. There were no significant associations to any other variables examined. The risk of chronic pain after laparoscopic cholecystectomy is relatively low, but significantly related to the visceral pain response during the first postoperative week.
Chronic postoperative pain after total knee replacement (TKR) in knee osteoarthritis (KOA) implies clinical challenges. Widespread hyperalgesia, facilitated temporal summation of pain (TSP), and ...impaired conditioned pain modulation (CPM) have been found in painful KOA. This exploratory study investigated postoperative pain relief 12 months after TKR in 4 subgroups of patients preoperatively profiled by mechanistic quantitative sensory testing. In 103 patients with KOA, pressure pain detection threshold (PDT) and tolerance thresholds (PTT) were assessed at the lower leg using cuff algometry. Temporal summation of pain was measured as an increase in pain intensity scores during 10 repeated (2 seconds intervals) painful cuff stimuli. Conditioned pain modulation was calculated as the relative increase in PDT during painful conditioning stimulation. The grand averages of TSP and CPM were calculated and values below or above were used for subgrouping: facilitated TSP/impaired CPM (group A, N = 16), facilitated TSP/normal CPM (group B, N = 15), normal TSP/impaired CPM (group C, N = 44), and normal TSP/normal CPM (group D, N = 28). Clinical VAS pain intensity scores were collected before and 12 months after TKR surgery and the pain relief calculated. Less pain relief was found in group A (52.0% ± 14.0% pain relief) than in group B (81.1% ± 3.5%, P = 0.023) and group C (79.6% ± 4.4%, P = 0.007), but not group D (69.4% ± 7.9%, P = 0.087). Low preoperative PDT was associated with a less postoperative pain relief (R = -0.222, P = 0.034), whereas TSP or CPM alone showed no associations with postoperative pain relief. This explorative study indicated that patients with osteoarthritis with facilitated TSP together with impaired CPM are more vulnerable to experience less pain relief after TKR.
Rebound pain is a common, yet under-recognised acute increase in pain severity after a peripheral nerve block (PNB) has receded, typically manifesting within 24 h after the block was performed. This ...retrospective cohort study investigated the incidence and factors associated with rebound pain in patients who received a PNB for ambulatory surgery.
Ambulatory surgery patients who received a preoperative PNB between March 2017 and February 2019 were included. Rebound pain was defined as the transition from well-controlled pain (numerical rating scale NRS ≤3) while the block is working to severe pain (NRS ≥7) within 24 h of block performance. Patient, surgical, and anaesthetic factors were analysed for association with rebound pain by univariate, multivariable, and machine learning methods.
Four hundred and eighty-two (49.6%) of 972 included patients experienced rebound pain as per the definition. Multivariable analysis showed that the factors independently associated with rebound pain were younger age (odds ratio OR 0.98; 95% confidence interval CI 0.97–0.99), female gender (OR 1.52 1.15–2.02), surgery involving bone (OR 1.82 1.38–2.40), and absence of perioperative i.v. dexamethasone (OR 1.78 1.12–2.83). Despite a high incidence of rebound pain, there were high rates of patient satisfaction (83.2%) and return to daily activities (96.5%).
Rebound pain occurred in half of the patients and showed independent associations with age, female gender, bone surgery, and absence of intraoperative use of i.v. dexamethasone. Until further research is available, clinicians should continue to use preventative strategies, especially for patients at higher risk of experiencing rebound pain.
Complex regional pain syndrome (CRPS) develops after-limb injury, with persistent pain and deficits in movement frequently co-occurring. The striatum is critical for mediating multiple mechanisms ...that are often aberrant in CRPS, which includes sensory and pain processing, motor function, and goal-directed behaviors associated with movement. Yet, much remains unknown with regards to the morphological and functional properties of the striatum and its subregions in this disease. Thus, we investigated 20 patients (15 female, age 58 ± 9 years, right-handed) diagnosed with chronic (6+ months of pain duration) CRPS in the right hand and 20 matched, healthy controls with anatomical and resting-state, functional magnetic resonance imaging. In addition, a comprehensive clinical and behavioral evaluation was performed, where each participant's pain, motor function, and medical history were assessed. Complex regional pain syndrome patients harbored significant abnormalities in hand coordination, dexterity, and strength. These clinical pain- and movement-related findings in CRPS patients were concomitant with bilateral decreases in gray matter density in the putamen as well as functional connectivity increases and decreases among the putamen and pre-/postcentral gyri and cerebellum, respectively. Importantly, higher levels of clinical pain and motor impairment were associated with increased putamen-pre-/postcentral gyri functional connectivity strengths. Collectively, these findings suggest that putaminal alterations, specifically the functional interactions with sensorimotor structures, may underpin clinical pain and motor impairment in chronic CRPS patients.
Although robotic-assisted thoracic surgery (RATS) provides improved dexterity, the effect of RATS on pain compared with video-assisted thoracoscopic surgery (VATS) or open lobectomy is poorly ...understood. This study evaluated acute and chronic pain following RATS, VATS, and open anatomic pulmonary resection.
A retrospective review of 498 patients (502 procedures) who underwent RATS (74), VATS (227), and open (201) anatomic pulmonary resection including lobectomy and segmentectomy from 2010 to 2014 was performed to identify factors related to acute and chronic pain. Acute pain scores were analyzed over the first 9 postoperative days. Chronic pain was assessed using the validated PainDETECT survey.
There were no significant differences in acute or chronic pain between RATS and VATS. There was a significant decrease in acute pain for patients with minimally invasive surgery (P = .0004). Chronic numbness was significantly higher after open resection (25.5% vs 11.6%; P = .0269) but with no difference in other symptoms of chronic pain. Despite no significant difference in pain scores, 69.2% of patients who received RATS felt the approach affected pain versus 44.2% VATS (P = .0330). On multivariable analysis, younger age (P < .0001), female gender (P = .0364), and baseline narcotic use (P = .0142) were associated with acute pain, whereas younger age (P = .0021) and major complications (P = .0003) were associated with chronic numbness in patients who received MIS.
Although minimally invasive approaches resulted in less acute pain and chronic numbness, there were no significant differences between RATS and VATS. In contrast, more RATS patients believed the approach affected their pain, suggesting a difference between reality and perception.
Opioid therapy for chronic noncancer pain (CNCP) is controversial due to concerns regarding long-term effectiveness and safety, particularly the risk of tolerance, dependence, or abuse.
To assess ...safety, efficacy, and effectiveness of opioids taken long-term for CNCP.
We searched 10 bibliographic databases up to May 2009.
We searched for studies that: collected efficacy data on participants after at least 6 months of treatment; were full-text articles; did not include redundant data; were prospective; enrolled at least 10 participants; reported data of participants who had CNCP. Randomized controlled trials (RCTs) and pre-post case-series studies were included.
Two review authors independently extracted safety and effectiveness data and settled discrepancies by consensus. We used random-effects meta-analysis' to summarize data where appropriate, used the I(2) statistic to quantify heterogeneity, and, where appropriate, explored heterogeneity using meta-regression. Several sensitivity analyses were performed to test the robustness of the results.
We reviewed 26 studies with 27 treatment groups that enrolled a total of 4893 participants. Twenty five of the studies were case series or uncontrolled long-term trial continuations, the other was an RCT comparing two opioids. Opioids were administered orally (number of study treatments groups abbreviated as "k" = 12, n = 3040), transdermally (k = 5, n = 1628), or intrathecally (k = 10, n = 231). Many participants discontinued due to adverse effects (oral: 22.9% 95% confidence interval (CI): 15.3% to 32.8%; transdermal: 12.1% 95% CI: 4.9% to 27.0%; intrathecal: 8.9% 95% CI: 4.0% to 26.1%); or insufficient pain relief (oral: 10.3% 95% CI: 7.6% to 13.9%; intrathecal: 7.6% 95% CI: 3.7% to 14.8%; transdermal: 5.8% 95% CI: 4.2% to 7.9%). Signs of opioid addiction were reported in 0.27% of participants in the studies that reported that outcome. All three modes of administration were associated with clinically significant reductions in pain, but the amount of pain relief varied among studies. Findings regarding quality of life and functional status were inconclusive due to an insufficient quantity of evidence for oral administration studies and inconclusive statistical findings for transdermal and intrathecal administration studies.
Many patients discontinue long-term opioid therapy (especially oral opioids) due to adverse events or insufficient pain relief; however, weak evidence suggests that patients who are able to continue opioids long-term experience clinically significant pain relief. Whether quality of life or functioning improves is inconclusive. Many minor adverse events (like nausea and headache) occurred, but serious adverse events, including iatrogenic opioid addiction, were rare.
Chronic neuropathic pain has been recognized as contributing to a significant proportion of chronic pain globally. Among these, spinal pain is of significance with failed back surgery syndrome ...(FBSS), generating considerable expense for the health care systems with increasing prevalence and health impact.
To assess the role and effectiveness of spinal cord stimulation (SCS) in chronic spinal pain.
A systematic review of randomized controlled trials (RCTs) of SCS in chronic spinal pain.
The available literature on SCS was reviewed. The quality assessment criteria utilized were Cochrane review criteria to assess sources of risk of bias and Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment (IPM - QRB) criteria for randomized trials.The level of evidence was based on a best evidence synthesis with modified grading of qualitative evidence from Level I to Level V.Data sources included relevant literature published from 1966 through March 2015 that were identified through searches of PubMed and EMBASE, manual searches of the bibliographies of known primary and review articles, and all other sources.
RCTs of efficacy with a minimum 12-month follow-up were considered for inclusion. For trials of adaptive stimulation, high frequency stimulation, and burst stimulation, shorter follow-up periods were considered.
Results showed 6 RCTs with 3 efficacy trials and 3 stimulation trials. There were also 2 cost effectiveness studies available. Based on a best evidence synthesis with 3 high quality RCTs, the evidence of efficacy for SCS in lumbar FBSS is Level I to II. The evidence for high frequency stimulation based on one high quality RCT is Level II to III. Based on a lack of high quality studies demonstrating the efficacy of adaptive stimulation or burst stimulation, evidence is limited for these 2 modalities.
The limitations of this systematic review continue to require future studies illustrating effectiveness and also the superiority of high frequency stimulation and potentially burst stimulation.
There is significant (Level I to II) evidence of the efficacy of spinal cord stimulation in lumbar FBSS; whereas, there is moderate (Level II to III) evidence for high frequency stimulation; there is limited evidence for adaptive stimulation and burst stimulation.
Persistent Post-Mastectomy Pain (PPMP) is a common condition that can follow surgeries for breast cancer, the most common cancer in women. Because of the frequency of PPMP and its potential severity, ...it has received increasing research attention. This manuscript reviews the recent research literature, beginning with a brief history and then relevant medical, surgical, demographic, and psychosocial risk factors. Subsequently, social, psychological, and functional sequelae that have been linked to PPMPS are considered, as is research on current pharmacological, psychological, and rehabilitative approaches to treatment. The review concludes with a discussion of directions for future research and treatment that might reduce the incidence and impact of PPMP on breast cancer survivors. PERSPECTIVE: This article describes current research literature involving mechanisms, risks, and treatments related to persistent post-mastectomy pain. Implications of research findings also are discussed for pre- and post-surgical approaches to pain management, current treatments, and promising research directions.
Chronic low back pain (cLBP) is the most prevalent chronic pain condition. There are no treatments that haven been found to directly assuage evoked cLBP. To this extent, mindfulness-meditation is a ...promising pain therapy. Yet, it is unclear if meditation can be utilized to directly attenuate evoked chronic pain through endogenous opioids. A double-blind, randomized, and placebo-controlled clinical trial with a drug crossover design examined if mindfulness-meditation, as compared to sham mindfulness-meditation, attenuated straight leg-raise test evoked chronic pain during intravenous (0.15 mg/kg bolus + 0.15 mg/kg/hour maintenance) naloxone (opioid antagonist) and placebo-saline infusion. Fifty-nine individuals with cLBP (mean age = 46 years; 30 females) completed all study procedures. After the pre-intervention pain testing session, patients were randomized to a four-session (20-min/session) mindfulness (n = 30) or sham mindfulness-meditation (n = 29) intervention. After the interventions, mindfulness and sham mindfulness-meditation were associated with significant reductions in back pain during saline and naloxone infusion when compared to rest (non-meditation) in response to the cLBP-evoking straight leg-raise test. These results indicate that meditation directly reduces evoked chronic pain through non-opioidergic processes. Importantly, after the interventions, the mindfulness group reported significantly lower straight leg-raise induced pain than the sham mindfulness-meditation group during rest (non-meditation) and meditation. Mindfulness and sham mindfulness-meditation training was also associated with significantly lower Brief Pain Inventory severity and interference scores. The pain-relieving effects of mindfulness meditation were more pronounced than a robust sham-mindfulness meditation intervention, suggesting that non-reactive appraisal processes may be uniquely associated with improvements in chronic low-back pain.Trial Registration: ClinicalTrials.gov identifier: NCT04034004.
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