Heart rate variability in sciatica patients referred to spine surgery: a case control study

Relation between heart rate variability and spectral analysis of electroencephalogram in chronic neuropathic pain patients

Chronic neuropathic pain (CNP) is a complex condition often arising from neural maladaptation after nerve injury. Understanding CNP complications involves the intricate interplay between brain-heart dynamics, assessed through quantitative electroencephalogram (qEEG) and heart rate variability (HRV). However, insights into their interaction in chronic pain are limited. Resting EEG and simultaneous electrocardiogram (lead II) of the participants were recorded for qEEG and HRV analysis. Correlations between HRV and qEEG parameters were calculated and compared with age, sex, and body mass index (BMI)-matched controls. CNP patients showed reduced HRV and significant increases in qEEG power spectral densities within delta, theta, and beta frequency ranges. A positive correlation was found between low frequency/ high frequency (LF/HF) ratio in HRV analysis and theta, alpha, and beta frequency bands in qEEG among CNP patients. However, no significant correlation was observed between parasympathetic indices and theta, beta bands in qEEG within CNP group, unlike age, sex, and BMI-matched healthy controls. CNP patients display significant HRV reductions and distinctive qEEG patterns. While healthy controls exhibit significant correlations between parasympathetic HRV parameters and qEEG spectral densities, these relationships are diminished or absent in CNP individuals. LF/HF ratio, reflecting sympathovagal balance, correlates significantly with qEEG frequency bands (theta, alpha, beta), illuminating autonomic dysregulation in CNP. These findings emphasize the intricate brain-heart interplay in chronic pain, warranting further exploration.

Muscle activity and rehabilitation in spinal stenosis (MARSS) after conservative therapy and surgical decompression with or without fusion: Protocol for a partially randomized patient preference trial on rehabilitation timing

Background

Patients affected by lumbar spinal stenosis (LSS) suffer from a multifactorial degeneration of the lumbar spine resulting in narrowing of the neuroforamina and spinal canal, leading to various functional limitations. It remains unclear whether LSS patients after surgery would benefit from early post-operative rehabilitation, or if a delayed rehabilitation would be more advantageous. The purpose of this partially randomized patient preference trial is to evaluate the impact of post-operative rehabilitation timing as well as surgical intervention type on psychometric properties and functional outcomes in patients with LSS.

Methods

Data for this patient preference trial are collected before and after surgical (decompression only or decompression and fusion) and rehabilitative interventions as well as six, 12 and 24 months after completing rehabilitation. The study participants are patients diagnosed with LSS who are at least 18 years old. After a medical check-up, participants will complete patient-reported outcome measures (PAREMO-20, SIBAR, FREM-8, SF-12, SFI, ODI) and different functional assessments (functional reach test, loaded reach test, handgrip strength, standing balance control, 6-min walk test).

Ethics and dissemination

The results of this study will be published through peer-reviewed publications and scientific contributions at national and international conferences. This research has been approved by the Institutional Review Board of Martin Luther University Halle-Wittenberg (reference number: 2022-128).

Effects of remote ischemic conditioning on conditioned pain modulation and cardiac autonomic modulation in women with knee osteoarthritis: placebo-controlled randomized clinical trial protocol

BACKGROUND

It is estimated that over 240 million people worldwide have osteoarthritis, which is a major contributor to chronic pain and central changes in pain processing, including endogenous pain modulation. The autonomic nervous system plays a crucial role in the pain regulatory process. One of the main mechanisms of remote ischemic conditioning is neuronal signaling from the preconditioned extremity to the heart. This study aims to analyze the acute effect of remote ischemic conditioning on local pain, conditioned pain modulation, and cardiac autonomic control in women with knee osteoarthritis and to see if there is a correlation between them.

METHODS

Women more than 50 years with knee osteoarthritis diagnosed according to the American College of Rheumatology criteria in the postmenopausal period will be considered eligible. The study will have blind randomization, be placebo-controlled, and be balanced in a 1:1 ratio. The total of 44 participants will be divided into two groups (22 participants per group): (i) remote ischemic conditioning and (ii) placebo remote ischemic conditioning. Protocol consisting of four cycles of total ischemia, followed immediately by four cycles of 5 min of vascular reperfusion, totaling 40 min. The primary outcomes in the protocol are conditioned pain modulation, which has the pressure pain threshold (kgf/cm2) as its primary outcome measure, and cardiac autonomic modulation, which has the indices found in heart rate variability as its primary outcome measure. Comparisons will be performed using generalized linear mixed models fitted to the data. For correlation, the Pearson or Spearman test will be used depending on the normality of the data. All analyses will assume a significance level of p < 0.05.

DISCUSSION

It is believed that the results of this study will present a new perspective on the interaction between the pain processing system and the cardiovascular system; they will provide the professional and the patient with a greater guarantee of cardiovascular safety in the use of the intervention; it will provide knowledge about acute responses and this will allow future chronic intervention strategies that aim to be used in the clinical environment, inserted in the multimodal approach, for the treatment of osteoarthritis of the knee.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05059652. Registered on 30 August 2021. Last update on 28 March 2023.

Sensor Technologies to Manage the Physiological Traits of Chronic Pain: A Review

Non-oncologic chronic pain is a common high-morbidity impairment worldwide and acknowledged as a condition with significant incidence on quality of life. Pain intensity is largely perceived as a subjective experience, what makes challenging its objective measurement. However, the physiological traces of pain make possible its correlation with vital signs, such as heart rate variability, skin conductance, electromyogram, etc., or health performance metrics derived from daily activity monitoring or facial expressions, which can be acquired with diverse sensor technologies and multisensory approaches. As the assessment and management of pain are essential issues for a wide range of clinical disorders and treatments, this paper reviews different sensor-based approaches applied to the objective evaluation of non-oncological chronic pain. The space of available technologies and resources aimed at pain assessment represent a diversified set of alternatives that can be exploited to address the multidimensional nature of pain.

Targeting the Autonomic Nervous System Balance in Patients with Chronic Low Back Pain Using Transcranial Alternating Current Stimulation: A Randomized, Crossover, Double-Blind, Placebo-Controlled Pilot Study

Background

Chronic low back pain (CLBP) is characterized by an alteration in pain processing by the central nervous system that may affect autonomic nervous system (ANS) balance. Heart rate variability (HRV) reflects the balance of parasympathetic and sympathetic ANS activation. In particular, respiratory sinus arrhythmia (RSA) solely reflects parasympathetic input and is reduced in CLBP patients. Yet, it remains unknown if non-invasive brain stimulation can alter ANS balance in CLBP patients.

Objective

To evaluate if non-invasive brain stimulation modulates the ANS, we analyzed HRV metrics collected in a previously published study of transcranial alternating current stimulation (tACS) for the modulation of CLBP through enhancing alpha oscillations. We hypothesized that tACS would increase RSA.

Methods

A randomized, crossover, double-blind, sham-controlled pilot study was conducted to investigate the effects of 10Hz-tACS on metrics of ANS balance calculated from electrocardiogram (ECG). ECG data were collected for 2 mins before and after 40 mins of 10Hz-tACS or sham stimulation.

Results

There were no significant changes in RSA or other frequency-domain HRV components from 10Hz-tACS. However, exploratory time-domain HRV analyses revealed a significant increase in the standard deviation of normal intervals between R-peaks (SDNN), a measure of ANS balance, for 10Hz-tACS relative to sham.

Conclusion

Although tACS did not significantly increase RSA, we found in an exploratory analysis that tACS modulated an integrated HRV measure of both ANS branches. These findings support the further study of how the ANS and alpha oscillations interact and are modulated by tACS.

ClinicalTrials.gov

Transcranial Alternating Current Stimulation in Back Pain – Pilot Study, NCT03243084.

Are 15-Year Trajectories of Low Back Pain and Sciatica Associated With Cardiovascular Autonomic Function in the General Population?: The Northern Finland Birth Cohort 1966 Study

STUDY DESIGN

A population-based cohort study.

OBJECTIVE

The aim of this study was to examine whether 15-year trajectories of low back pain (LBP) and sciatica are associated with cardiovascular autonomic function in a large general population sample.

SUMMARY OF BACKGROUND DATA

Previous studies using mainly small patient samples have suggested that LBP and sciatica are associated with abnormal cardiovascular autonomic function, namely altered heart rate variability (HRV) and baroreflex sensitivity (BRS). We examined this association in a large general population sample.

METHODS

The data collections of the Northern Finland Birth Cohort 1966 consisted of pain questionnaires at 31 and 46 years (history of LBP, sciatica, and other musculoskeletal pains during the previous year; yes/no for each) and measurements of HRV and BRS at 46 years (heart rate, HR; root mean square of successive differences in beat-to-beat intervals, rMSSD; low-frequency systolic blood pressure variability, SBPV; cross-spectral BRS, BRS; each while seated and standing). The data collections also comprised several confounders. Trajectories for LBP, sciatica, and both together ("no pain," "decreasing," "increasing," "long-term pain") were constructed and general linear models were used to perform comparisons between trajectories (for HR/rMSSD, n = 3398; for SBPV/BRS, n = 1667).

RESULTS

In the crude models, LBP and sciatica were associated with higher HR, lower rMSSD, higher SBPV, and lower BRS, but these associations were mostly attenuated by adjustments. Regarding both LBP and sciatica, only the "increasing" trajectory was associated with two of the eight outcomes (standing SBPV, seated BRS) after adjustments. Regarding LBP, the "increasing" trajectory was associated with three (standing SBPV, seated BRS, standing BRS), the "long-term pain" trajectory with one (standing BRS), and the "decreasing" trajectory with one outcome (seated SBPV) after adjustments. Sciatica showed no association with the outcomes after adjustments.

CONCLUSION

We conclude that the 15-year trajectories of LBP and sciatica do not have a consistent independent association with cardiovascular autonomic function among the general population.

LEVEL OF EVIDENCE

3.

Musculoskeletal pains and cardiovascular autonomic function in the general Northern Finnish population

BACKGROUND

Heart rate variability (HRV) and baroreflex sensitivity (BRS) measurements provide means for the objective assessment of cardiovascular autonomic function. As previous studies have associated chronic pain with abnormal autonomic function, we aimed to characterize the relationship between the number of musculoskeletal pain sites (NPS), pain intensity, and cardiovascular autonomic function among the population-based Northern Finland Birth Cohort 1966.

METHODS

At the age of 46, cohort members self-reported their musculoskeletal pains (enabling the determination of NPS [0-8] and pain intensity [Numerical Rating Scale, NRS, 0-10]) and underwent clinical assessments of cardiovascular autonomic function in seated and standing positions (HRV variables: heart rate [HR] and root mean square of successive differences in beat-to-beat intervals [rMSSD] for the entire cohort; BRS variables: low-frequency systolic blood pressure variability [SBPV] and cross-spectral baroreflex sensitivity [BRS] for those attending the examination in Oulu, Finland). Extensive confounder data were also collected (body mass index, physical activity, smoking, Hopkins Symptom Checklist-25, comorbidities, and medications). The full samples included 4186 and 2031 individuals (HRV and BRS samples, respectively). Three subanalyses focused on individuals with intense and frequent pain, individuals with symptoms of depression and anxiety, and the relationship between pain intensity and autonomic parameters.

RESULTS

Linear regression models showed varying associations between NPS, pain intensity, and cardiovascular autonomic parameters. However, after all adjustments NPS was only associated with one outcome among women (BRS, standing: beta = - 0.015, p = 0.048) and two among men (HR, seated: beta = - 0.902, p = 0.003; HR, standing: beta = - 0.843, p = 0.014). Pain intensity was not associated with any outcome after full adjustments. Significant sex*pain interactions were found in the data.

CONCLUSIONS

Our data suggest that musculoskeletal pain has, at most, a limited independent association with cardiovascular autonomic function. Future studies should carefully account for the potential confounders and sex interactions that this study revealed.

Short-term assessment of autonomic nervous system as a potential tool to quantify pain experience

Various pain conditions may result in altered autonomic nervous system regulation. We evaluated whether autonomic regulation, analyzed with short-term heart rate variability (HRV), differs between low back pain (LBP) patients and healthy controls. Additionally, we tested if short-term HRV recordings are feasible and informative in planning home monitoring of LBP patients. The study population consisted of 16 volunteers (8 LBP patients and 8 healthy subjects) (age 42±10 years, body mass index 26±4 kg/m2, 7 men and 9 women). Usually 3- to 5-minute R-R interval recordings have been used as short-term recordings of HRV, but recent evidence supports even shorter R-R interval recording procedure for short-term HRV assessment. We collected R-R interval data for 1 minute in sitting, standing and bending down tasks. Mean heart rate (HR) and vagally mediated beat-to-beat variability (SD1 and rMSSD) were analyzed. The results showed that autonomic nervous system function assessed with the short-term measurement HRV method differentiates LBP patients from healthy controls in sitting and standing. Vagally mediated SD1 and rMSSD were significantly lower and the HR was higher among the patients compared to the controls. A novel finding was also the feasibility of 1-minute measurement of HRV, which may open entirely new opportunities to assess accurately concomitant changes in autonomic nervous system function and self-reported individual pain experience. This could lead to a more personalized pain treatment and more efficient health care resource allocation as the new measurement methods is more suitable for home monitoring than the previously used ones.

A Prospective Comparison Study of Heart Rate Variability During Menses in Young Women With Dysmenorrhea

Background:

Numerous studies have demonstrated autonomic abnormalities in various pain conditions. However, few have investigated heart rate variability (HRV) in young women with primary dysmenorrhea, and the conclusions have been inconsistent. More evidence is required to confirm the reported trend for consistent fluctuation of HRV parameters in dysmenorrhea.

Purpose:

The study’s aim was to determine whether significant differences exist between young women with and without dysmenorrhea for heart rate (HR), blood pressure (BP), and HRV parameters during menses.

Design:

A prospective comparison design with repeated measures was used.

Setting and participants:

Sixty-six women aged 18–25 with dysmenorrhea and 54 eumenorrheic women were recruited from a university in northern Taiwan.

Methods:

High-frequency and low-frequency HRV parameters (HF and LF), LF/HF ratio, BP, and HR were measured daily between 8 p.m. and 10 p.m. from Day 1 to Day 6 during menses. The generalized estimating equation was used to analyze the effects of group, time, and Group × Time interaction on these variables.

Results:

HF values were significantly lower in the dysmenorrhea than in the eumenorrhea group, but there were no differences in BP, HR, LF, or LF/HF ratio.

Conclusion:

Reduced HF values reflect reduced parasympathetic activity and autonomic instability in young women with dysmenorrhea. Future longitudinal studies are warranted to examine autonomic regulation in menstrual pain of varying intensities associated with dysmenorrhea-related symptoms and to clarify the causal relationship between dysmenorrhea and HRV fluctuations.

The Effect of Smoking on the Risk of Sciatica: A Meta-analysis

BACKGROUND

The role of smoking in sciatica is unknown. This study aimed to estimate the effect of smoking on lumbar radicular pain and clinically verified sciatica.

METHODS

Comprehensive literature searches were conducted in PubMed, Embase, Web of Science, Scopus, Google Scholar, and ResearchGate databases from 1964 through March 2015. We used a random-effects meta-analysis, assessed heterogeneity and publication bias, and performed sensitivity analyses with regard to study design, methodological quality of included studies, and publication bias.

RESULTS

Twenty-eight (7 cross-sectional [n = 20,111 participants], 8 case control [n = 10,815], and 13 cohort [n = 443,199]) studies qualified for a meta-analysis. Current smokers had an increased risk of lumbar radicular pain or clinically verified sciatica (pooled adjusted odds ratio [OR] 1.46; 95% confidence interval [CI], 1.30-1.64, n = 459,023). Former smokers had only slightly elevated risk compared with never smokers (pooled adjusted OR 1.15; 95% CI, 1.02-1.30, n = 387,196). For current smoking the pooled adjusted OR was 1.64 (95% CI, 1.24-2.16, n = 10,853) for lumbar radicular pain, 1.35 (95% CI, 1.09-1.68, n = 110,374) for clinically verified sciatica, and 1.45 (95% CI, 1.16-1.80, n = 337,796) for hospitalization or surgery due to a herniated lumbar disc or sciatica. The corresponding estimates for past smoking were 1.57 (95% CI, 0.98-2.52), 1.09 (95% CI, 1.00-1.19), and 1.10 (95% CI, 0.96-1.26). The associations did not differ between men and women, and they were independent of study design. Moreover, there was no evidence of publication bias, and the observed associations were not due to selection or detection bias, or confounding factors.

CONCLUSIONS

Smoking is a modest risk factor for lumbar radicular pain and clinically verified sciatica. Smoking cessation appears to reduce, but not entirely eliminate, the excess risk.

Efficacy and Safety of Acupuncture for Acute Low Back Pain in Emergency Department: A Pilot Cohort Study

Introduction. Low back pain (LBP) is one of the most common complaints in the emergency department (ED). There are several research articles providing evidence for acupuncture for treating chronic LBP but few about treating acute LBP. This study assessed the efficacy and safety of acupuncture for the treatment of acute LBP in the ED. Materials and methods. A clinical pilot cohort study was conducted. 60 participants, recruited in the ED, were divided into experimental and control groups with 1 dropout during the study. Life-threatening conditions or severe neurological defects were excluded. The experimental group (n = 45) received a series of fixed points of acupuncture. The control group (n = 14) received sham acupuncture by pasting seed-patches near acupoints. Back pain was measured using the visual analog scale (VAS) at three time points: baseline and immediately after and 3 days after intervention as the primary outcome. The secondary outcomes were heart rate variability (HRV) and adverse events. Results. The VAS demonstrated a significant decrease (P value <0.001) for the experimental group after 15 minutes of acupuncture. The variation in HRV showed no significant difference in either group. No adverse event was reported. Conclusion. Acupuncture might provide immediate effect in reducing the pain of acute LBP safely.

A New Definition of BMI Scale by Relationship between Respiration and Unconscious Behavior during Sleep with Body Motion Wave

Recently, health problems due to overwork, apparent suicide produced by the progress of the social stress and lifestyle diseases and lifestyle diseases like hyperpiesia or obesity have been reported. From this, it has become of interest to avoid these problems and to keep the health. However, the indicators for health control and physical condition haven't been defined. Body Mass Index (BMI) has traditionally been used as an indicator of health. But, there are many unclear points left in the criteria of BMI to utilize. Sleep would be an important theme to know and to keep health. During sleep, the biological information related to health state would be appeared because of predominant activity of autonomic nervous system under the state of unconsciousness. From these, the authors investigated the relationship between BMI and autonomic nervous activity. Nineteen healthy young adults participated in this study and performed sleep experiment by adopting a pressure sensor named “dynamic air-pressure sensor” and a pressure sensor array. As a result, the authors found some relationships among respiration state, motions of muscles and unconscious behavior depending on BMI. This result about sleep behavior would suggest a new definition for BMI. For example, large value of BMI brings influences, maybe bad, to respiratory behavior during sleep.