Preoperative pain sensitivity and its correlation with postoperative acute and chronic pain: a systematic review and meta-analysis.

BACKGROUND: Preoperative pain sensitivity (PPS) can be associated with postsurgical pain. However, estimates of this association are scarce. Confirming this correlation is essential to identifying patients at high risk for severe postoperative pain and for developing analgesic strategy. This systematic review and meta-analysis summarises PPS and assessed its correlation with postoperative pain. METHODS: PubMed, Scopus, Cochrane Library, and PsycINFO were searched up to October 1, 2023, for studies reporting the association between PPS and postsurgical pain. Two authors abstracted estimates of the effect of each method independently. A random-effects model was used to combine data. Subgroup analyses were performed to investigate the effect of pain types and surgical procedures on outcomes. RESULTS: A total of 70 prospective observational studies were included. A meta-analysis of 50 studies was performed. Postoperative pain was negatively associated with pressure pain threshold (PPT; r=-0.15, 95% confidence interval [CI] -0.23 to -0.07]) and electrical pain threshold (EPT; r=-0.28, 95% CI -0.42 to -0.14), but positively correlated with temporal summation of pain (TSP; r=0.21, 95% CI 0.12-0.30) and Pain Sensitivity Questionnaire (PSQ; r=0.25, 95% CI 0.13-0.37). Subgroup analysis showed that only TSP was associated with acute and chronic postoperative pain, whereas PPT, EPT, and PSQ were only associated with acute pain. A multilevel (three-level) meta-analysis showed that PSQ was not associated with postoperative pain. CONCLUSIONS: Lower PPT and EPT, and higher TSP are associated with acute postoperative pain while only TSP is associated with chronic postoperative pain. Patients with abnormal preoperative pain sensitivity should be identified by clinicians to adopt early interventions for effective analgesia. SYSTEMATIC REVIEW PROTOCOL: PROSPERO (CRD42023465727).

Long-Term Outcomes of High-Dose Conbercept Treatment for Myopic Choroidal Neovascularization and Idiopathic Choroidal Neovascularization.

INTRODUCTION: The aim of the study was to report 2-year outcomes of intravitreal injection of high-dose conbercept (1 mg 2 + PRN scheme) for subjects with myopic choroidal neovascularization (mCNV) and idiopathic choroidal neovascularization (iCNV) by optical coherence tomography angiography follow-up. METHODS: A total of 38 subjects (38 eyes) were enrolled in this retrospective study, which were divided into group A (mCNV, 20 subjects, 20 eyes) and group B (iCNV, 18 subjects, 18 eyes). All subjects received 1.0 mg of conbercept intravitreally at diagnosis and again 35 days later. Additional conbercept injection was administered upon findings of decreased best-corrected visual acuity (BCVA); metamorphosis aggravation, macular hemorrhage, or edema; increased central retinal thickness (CRT); or leakage observed by fluorescein angiography. The BCVA, CRT, and CNV areas of the two groups were evaluated at baseline and at 1, 2, 4, 6, 12, and 24 months after surgery. RESULTS: The BCVA of group A improved from 0.31 ± 0.16 logMAR at baseline to 0.12 ± 0.03 logMAR at the final follow-up (p < 0.001), while in group B the corresponding improvement was from 0.33 ± 0.16 logMAR at baseline to 0.12 ± 0.03 logMAR at the final follow-up (p < 0.001). Visual acuity improved in 17 subjects in group A and 15 in group B, while it remained stable in 3 subjects in each of groups A and B. CRT decreased from 311.83 ± 30.95 µm in group A and 351.17 ± 37.09 µm in group B preoperation to 229.56 ± 5.75 µm and 227.67 ± 4.98 µm at 24-month follow-up, respectively (p < 0.001 in groups A and B). Metamorphopsia was improved in subjects in groups A and B. CNV had disappeared in the two groups at the last postoperative visit. The BCVA, CRT, and CNV areas showed no statistical differences between the two groups at 6-, 12-, and 24-month follow-up (p > 0.05). CONCLUSION: Intravitreal injection of conbercept (1 mg 2 + PRN scheme) is effective for treating patients with mCNV or iCNV, which can improve and stabilize vision as well as dramatically alleviate metamorphopsia.

Non-invasive manipulation scheme of spherical particle in viscous fluids in a tube based on acoustic radiation force.

A theoretical solution of the acoustic radiation force (ARF) on spherical particles by an arbitrary beam in viscous fluids in a tube is proposed. Based on the parametric design with the purpose of promoting calculi in the urinary system, theoretical solutions and finite element simulations are carried out, which mutually confirm the accuracy and feasibility of the scheme. The variation law of the ARF with adjustable parameters, such as incident angle, frequency spectrum, particle radius, tube radius, and viscosity, is studied, and the mechanism of the variation law is explained. This solution lays a foundation for the application of non-contact and non-invasive in-tube manipulation based on ARF in medicine and life sciences.

Experimental study of the difference in deformation between normal and pathological, renal and bladder, cells induced by acoustic radiation force.

Previous studies have shown that alterations in the mechanical properties of cells may be associated with the onset and progression of some forms of pathology. In this paper, an experimental study of two types of cells, renal (cancer) and bladder (cancer) cells, is described which used acoustic radiation force (ARF) generated by a high-frequency ultrasound focusing transducer and performed on the operating platform of an inverted light microscope. Comparing images of cancer cells with those of normal cells of the same kind, we find that the cancer cells are more prone to deform than normal cells of the same kind under the same ARF. In addition, cancer cells with higher malignancy are more deformable than those with lower malignancy. This means that the deformability of cells may be used to distinguish diseased cells from normal ones, and more aggressive cells from less aggressive ones, which may provide a more rapid and accurate method for clinical diagnosis of urological disease in the future.

Does cognitive frailty predict delayed neurocognitive recovery after noncardiac surgery in frail elderly individuals? Probably not.

Introduction: Delayed neurocognitive recovery (DNR) is a common post-surgical complication among the elderly. Cognitive frailty (CF) is also an age-related medical syndrome. However, little is known about the association between CF and DNR. Therefore, this study aimed to study whether CF is associated with DNR in elderly patients undergoing elective noncardiac surgery, as well as to explore the potential risk factors for DNR in frail elderly individuals and construct a prediction model. Methods: This prospective cohort study administered a battery of cognitive and frailty screening instruments for 146 individuals (≥65 years old) scheduled for elective noncardiac surgery. Screening for CF was performed at least one day before surgery, and tests for the presence of DNR were performed seven days after surgery. The association between CF and DNR was investigated. Moreover, the study subjects were randomly divided into a modeling group (70%) and a validation group (30%). Univariate and multivariate logistic regression was performed to analyze the modeling group data and identify the independent risk factors for DNR. The R software was used to construct DNR's nomogram model, verifying the model. Results: In total, 138 individuals were eligible. Thirty-three cases were diagnosed with DNR (23.9%). No significant difference in the number of patients with CF was observed between the DNR and non-DNR groups (P > 0.05). Multivariate analysis after adjusting relevant risk factors showed that only the judgment of line orientation (JLOT) test score significantly affected the incidence of DNR. After internal validation of the constructed DNR prediction model, the area under the curve (AUC) of the forecast probability for the modeling population (n = 97) for DNR was 0.801, and the AUC for the validation set (n = 41) was 0.797. The calibration curves of both the modeling and validation groups indicate that the prediction model has good stability. Conclusion: Cognitive frailty is not an independent risk factor in predicting DNR after noncardiac surgery in frail elderly individuals. The preoperative JLOT score is an independent risk factor for DNR in frail elderly individuals. The prediction model has a good degree of discrimination and calibration, which means that it can individually predict the risk probability of DNR in frail elderly individuals.

Early Warning Value of ASL-MRI to Estimate Premorbid Variations in Patients With Early Postoperative Cognitive Dysfunctions.

Background: Postoperative cognitive dysfunction (POCD) is a general complication following cardiac and major non-cardiac surgery amongst the elderly, yet its causes and mechanisms are still unknown. The present study aimed to detect whether regional cerebral blood flow (CBF) is altered in the brain before surgery in POCD patients compared with non-POCD (NPOCD) patients, thus, CBF variation may potentially predict the occurrence of early POCD. Methods: Fifty patients scheduled for spinal stenosis surgery were enrolled in the study. All study participants completed a battery of neuropsychological tests (NPTs) by a well-trained neuropsychologist before the surgery and 1 week after the surgery. POCD was defined when the preoperative to postoperative difference of at least two of the NPTs' |Z|-scores with reference to a control group exceeded 1.96. Pulsed arterial spin-labeling (ASL) MRI was scanned at least 1 day before surgery. The ASLtbx toolkit and SPM12 were applied to preprocess and correct the images, which were then normalized to the MNI brain template space to obtain standardized cerebral perfusion images. Results: POCD was identified in 11 out of 50 patients (22%). The CBF of the right superior temporal lobe, right and left middle cingulate gyrus, and the right hippocampus, and parahippocampal gyrus in POCD group was lower than that in NPOCD group (P < 0.001). The CBF of the pars triangularis of inferior frontal gyrus in POCD group was higher than that in NPOCD group (P < 0.001). Conclusions: These preliminary findings suggest that CBF premorbid alterations may happen in cognitively intact elderly patients that develop early POCD. Alterations of preoperative CBF might be a bio-marker for early POCD that can be detected by noninvasive MRI scans.

Preparation of Graphene-Co/Ni/Fe3O4 Nanocomposites and Their Electrocatalytic Activity for Reduction of p-Nitrophenol.

Graphene-based nanocomposites of graphene-Co, graphene-Ni, and graphene-Fe3O4 were synthesized via improved chemical-carbothermal reduction using graphite and nitrates as starting materials. The Co, Ni, and Fe3O4 nanoparticles are uniformly loaded on the surfaces of graphene nanosheets without serious folds and conglomeration. The average dimensions of the Co, Ni, and Fe3O4 nanoparticles attached to graphene are approximately 50, 60, and 5 nm, respectively. Subsequently, three novel types of graphene-Co/Ni/Fe3O4 nanocomposite-modified glassy carbon electrodes (GCEs) were fabricated, and their electrocatalytic activity for reduction of p-nitrophenol was investigated by cyclic voltammetry in phosphate buffer solution. Results show that the current values increase as the scanning rate is increased from 70 mV·s-1 to 100 mV·s-1 and that the electrochemical reactions on the surface of the graphene-Co/Ni/Fe3O4-modified GCEs are diffusion controlled. Compared with the bare GCE, the graphene-Co/Ni/Fe3O4 nanocomposite-modified GCEs display considerably higher reduction peak current, which proves that the graphene-Co/Ni/Fe3O4 nanocomposites possess favorable electrocatalytic ability for reduction of p-nitrophenol.

Acoustic radiation force on a sphere in a progressive and standing zero-order quasi-Bessel-Gauss beam.

By means of series expansion theory, the incident quasi-Bessel-Gauss beam is expanded using spherical harmonic functions, and the beam coefficients of the quasi-Bessel-Gauss beam are calculated. According to the theory, the acoustic radiation force function, which is the radiation force per unit energy on a unit cross-sectional surface on a sphere made of diverse materials and immersed in an ideal fluid along the propagation axis of zero-order quasi-Bessel-Gauss progressive and standing beams, is investigated. The acoustic radiation force function is calculated as a function of the spherical radius parameter ka and the half-cone angle ß with different beam widths in a progressive and standing zero-order Bessel-Gauss beam. Simulation results indicate that the acoustic radiation forces with different waist radii demonstrate remarkably different features from those found in previous studies. The results are expected to be useful in potential applications such as acoustic tweezers.

Calculation of acoustical radiation force on microsphere by spherically-focused source.

Based on the ray acoustics approach, the trapping effects on a microsphere by an ideally spherically-focused ultrasound are discussed. The acoustical radiation force from a focused ultrasound beam on a spherical particle in a three-dimensional sound field is calculated considering the effect of the attenuation of the ultrasound beam both inside the particle and in the surrounding medium. The results show that as long as the particle is in the range of the ultrasound beam and as long as the appropriate parameters of the transducer are selected, the particle will be captured in the vicinity of the focus of the ultrasound beam. Also, the particle radius and different parameters of the transducer are analyzed for their affect on the radiation force.

Study of acoustic nonlinearity parameter imaging methods in reflection mode for biological tissues.

Three novel methods for acoustic nonlinearity parameter B/A imaging in reflection mode are developed in this paper. They are: (1) the acoustic nonlinearity parameter B/A tomography by detecting reflective second harmonic wave, (2) the B/A tomography in reflection mode via the measurement of the difference frequency wave generated by a parametric array, and (3) the C-scan imaging of B/A via the measurement of the echo second-harmonic signal. A theoretical analysis and the experimental imaging of normal and pathological biological tissues by using these methods are also present and discussed. Results show that using the acoustic nonlinearity parameter imaging we can more easily distinguish the diseased tissue from the normal one than using the linear acoustic parameters.