Spaceflight-associated pain.

PURPOSE OF REVIEW: Consequences of the expanding commercial spaceflight industry include an increase in total number of spaceflight participants and an accompanying surge in the average number of medical comorbidities compared with government-based astronaut corps. A sequela of these developments is an anticipated rise in acute and chronic pain concerns associated with spaceflight. This review will summarize diagnostic and therapeutic areas of interest that can support the comfort of humans in spaceflight. RECENT FINDINGS: Painful conditions that occur in space may be due to exposure to numerous stressors such as acceleration and vibration during launch, trauma associated with extravehicular activities, and morbidity resulting directly from weightlessness. Without normal gravitational forces and biomechanical stress, the hostile environment of space causes muscle atrophy, bone demineralization, joint stiffness, and spinal disc dysfunction, resulting in a myriad of pain generators. Repeated insults from abnormal environmental exposures are thought to contribute to the development of painful musculoskeletal and neuropathic conditions. SUMMARY: As humanity invests in Lunar and Martian exploration, understanding the painful conditions that will impede crew productivity and mission outcomes is critical. Preexisting pain and new-onset acute or chronic pain resulting from spaceflight will require countermeasures and treatments to mitigate long-term health effects.

Pro-Con Debate: Superior Versus Inferior Triangle Needle Placement in Transforaminal Epidural Injections.

Although transforaminal epidural injections have long been used for radicular pain, there is no universal standard injection approach to the neural foramen. The intervertebral foramen and its surrounding structures comprise an anatomically sensitive area that includes bone and joint structures, the intervertebral disk, blood vessels (in particular, the radicular arteries), the epidural sheath, and the spinal nerve root. Given the relatively high risk of inadvertent injury or injection to these nearby structures, image guidance for transforaminal epidural steroid injections (TFESIs) is standard of care. However, there is a lack of consensus regarding the optimal approach to the neural foramen: from the traditional superior ("safe") triangle or from the inferior (Kambin's) triangle. In this Pro-Con commentary article, we discuss the relative advantages and disadvantages of each approach for TFESIs.

The Use of Contrast Agents in Interventional Pain Procedures: A Multispecialty and Multisociety Practice Advisory on Nephrogenic Systemic Fibrosis, Gadolinium Deposition in the Brain, Encephalopathy After Unintentional Intrathecal Gadolinium Injection, and Hypersensitivity Reactions.

This Practice Advisory presents a comprehensive and evidence-based set of position statements and recommendations for the use of contrast media in interventional pain procedures. The advisory was established by an international panel of experts under the auspices of 11 multinational and multispecialty organizations based on a comprehensive review of the literature up to December 31, 2019. The advisory discusses the risks of using gadolinium-based contrast agents. These include nephrogenic systemic fibrosis, gadolinium brain deposition/retention, and encephalopathy and death after an unintentional intrathecal gadolinium injection. The advisory provides recommendations on the selection of a specific gadolinium-based contrast agent in patients with renal insufficiency, those who had multiple gadolinium-enhanced magnetic resonance imaging examinations, and in cases of paraspinal injections. Additionally, recommendations are made for patients who have a history of mild, moderate, or severe hypersensitivity reactions to contrast medium.

Pain Recognition With Electrocardiographic Features in Postoperative Patients: Method Validation Study.

BACKGROUND: There is a strong demand for an accurate and objective means of assessing acute pain among hospitalized patients to help clinicians provide pain medications at a proper dosage and in a timely manner. Heart rate variability (HRV) comprises changes in the time intervals between consecutive heartbeats, which can be measured through acquisition and interpretation of electrocardiography (ECG) captured from bedside monitors or wearable devices. As increased sympathetic activity affects the HRV, an index of autonomic regulation of heart rate, ultra-short-term HRV analysis can provide a reliable source of information for acute pain monitoring. In this study, widely used HRV time and frequency domain measurements are used in acute pain assessments among postoperative patients. The existing approaches have only focused on stimulated pain in healthy subjects, whereas, to the best of our knowledge, there is no work in the literature building models using real pain data and on postoperative patients. OBJECTIVE: The objective of our study was to develop and evaluate an automatic and adaptable pain assessment algorithm based on ECG features for assessing acute pain in postoperative patients likely experiencing mild to moderate pain. METHODS: The study used a prospective observational design. The sample consisted of 25 patient participants aged 18 to 65 years. In part 1 of the study, a transcutaneous electrical nerve stimulation unit was employed to obtain baseline discomfort thresholds for the patients. In part 2, a multichannel biosignal acquisition device was used as patients were engaging in non-noxious activities. At all times, pain intensity was measured using patient self-reports based on the Numerical Rating Scale. A weak supervision framework was inherited for rapid training data creation. The collected labels were then transformed from 11 intensity levels to 5 intensity levels. Prediction models were developed using 5 different machine learning methods. Mean prediction accuracy was calculated using leave-one-out cross-validation. We compared the performance of these models with the results from a previously published research study. RESULTS: Five different machine learning algorithms were applied to perform a binary classification of baseline (BL) versus 4 distinct pain levels (PL1 through PL4). The highest validation accuracy using 3 time domain HRV features from a BioVid research paper for baseline versus any other pain level was achieved by support vector machine (SVM) with 62.72% (BL vs PL4) to 84.14% (BL vs PL2). Similar results were achieved for the top 8 features based on the Gini index using the SVM method, with an accuracy ranging from 63.86% (BL vs PL4) to 84.79% (BL vs PL2). CONCLUSIONS: We propose a novel pain assessment method for postoperative patients using ECG signal. Weak supervision applied for labeling and feature extraction improves the robustness of the approach. Our results show the viability of using a machine learning algorithm to accurately and objectively assess acute pain among hospitalized patients. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/17783.

Use of occipital nerve block in emergency department treatment of status migrainosus.

Migraine headaches make up a significant proportion of emergency department visits. There are multiple pharmacologic treatment modalities for migraine abortive therapy; however, these treatments are rarely targeted to the precise area of pain and thus elicit multiple systemic effects. It has been well established in the anesthesia pain literature that occipital nerve blocks can provide not only immediate pain relief from occipital migraines, but can also result in a long-term resolution of occipital migraines. In this case report, we present how an occipital nerve block in the emergency department resulted in immediate and long-lasting resolution of a patient's occipital migraine.

Does Cervical Interlaminar Epidural Steroid Injection with Low-Dose Lidocaine Cause Objective Upper Extremity Weakness? A Preliminary Study.

OBJECTIVE: Low-dose local anesthetic is often used in cervical interlaminar epidural steroid injections (CIESI), yet its effect on upper extremity strength has not been studied. The presence of consequent weakness has potential implications for postprocedure safety. This study aimed to determine whether low-dose lidocaine in a C7-T1 CIESI causes objective weakness. DESIGN: Prospective case series. SETTING: Academic pain center. SUBJECTS: Adults, cervical radicular pain. METHODS: Participants underwent CIESI with 1 mL of 1% lidocaine (3 mL total injectate). Elbow flexion (EF), wrist extension (WE), elbow extension (EE), and handgrip strength were measured by dynamometry at baseline, 15 minutes, and 30 minutes postinjection. Changes in strength from baseline and the proportion of participants with a minimum perceptible change in EF, WE, EE, and handgrip strength (≥20%) and 95% confidence intervals (CIs) were calculated. RESULTS: Twenty-seven participants were included. At 15 and 30 minutes postinjection, there was no within-participant difference in EF, WE, EE, and handgrip strength from baseline overall. Nonetheless, five (19%, 95% CI = 4-33) of the participants demonstrated a 20% or greater strength decrease in at least one myotomal distribution. A 20% or greater decrease in strength was present in left EF 4% (95% CI = 0-11%), right EF 7% (95% CI = 0-17%), left WE 4% (95% CI = 0-11%), and right WE 7% (95% CI = 0-17%). CONCLUSIONS: The present data suggest that CIESI with an injectate volume of 3 mL that includes 1 mL of 1% lidocaine may result in objective upper extremity weakness that is above the minimum threshold of perception in a subset of patients.

Disease-modifying Antirheumatic Drugs for the Treatment of Low Back Pain: A Systematic Review of the Literature.

Low back pain (LBP) is a common source of pain and disability, which has an enormous adverse impact on affected individuals and the community as a whole. The etiologies of LBP are protean and local inflammation contributes to the majority of these processes. Although an array of potent disease-modifying anti-rheumatic drugs (DMARDs), which are typically anti-inflammatory in character, have become clinically available only corticosteroids are routinely used for the treatment of LBP. To further investigate this potentially underutilized therapy, we reviewed the available literature to determine the role of DMARDs in the treatment of LBP. Our results show that the current DMARD use for LBP is indeed limited in scope and is characterized by isolated use and empiric selection of drugs from a range of available DMARDs. Moreover, the dose, frequency, and route of drug administration are selected arbitrarily and deviated from treatment protocols proposed for the management of other inflammatory conditions. The literature published on this topic is of low quality, and the results of the reviewed trials were inconclusive or demonstrated only short-term efficacy of these medications. Based on the findings of this review, we recommend that the future DMARD use for LBP is initially limited to patients with debilitating disease who are unresponsive to conventional treatments, and the criteria for drug selection and routes of drug administration are clearly defined and may be modeled after treatment protocols for other inflammatory conditions.

Chronic pain for rheumatological disorders: Pathophysiology, therapeutics and evidence.

Pain is the leading reason people seek orthopedic and rheumatological care. By definition, most pain can be classified as nociceptive, or pain resulting from non-neural tissue injury or potential injury, with between 15% and 50% of individuals suffering from concomitant neuropathic pain or the newest category of pain, nociplastic pain, defined as "pain arising from altered nociception despite no clear evidence of actual or threatened tissue damage, or of a disease or lesion affecting the somatosensory system." Pain classification is important because it affects treatment decisions at all levels of care. Although several instruments can assist with classifying treatment, physician designation is the reference standard. The appropriate treatment of pain should ideally involve multidisciplinary care including physical therapy, psychotherapy and integrative therapies when appropriate, and pharmacotherapy with non-steroidal anti-inflammatory drugs for acute, mechanical pain, membrane stabilizers for neuropathic and nociplastic pain, and serotonin-norepinephrine reuptake inhibitors and tricyclic antidepressants for all types of pain. For nonsurgical interventions, there is evidence to support a small effect for epidural steroid injections for an intermediate-term duration, and conflicting evidence for radiofrequency ablation to provide at least 6months of benefit for facet joint pain, knee osteoarthritis, and sacroiliac joint pain. Since pain and disability represent the top reason for elective surgery, it should be reserved for patients who fail conservative interventions. Risk factors for procedural failure are the same as risk factors for conservative treatment failure and include greater disease burden, psychopathology, opioid use, central sensitization and multiple comorbid pain conditions, poorly controlled preoperative and postoperative pain, and secondary gain.

A Method to Determine Capabilities and Resources for Spacecraft Medical Systems.

INTRODUCTION: This paper describes the method for assigning medical diagnostic and treatment capabilities and resources to the database which assists with an updated probabilistic risk analysis (PRA) tool for exploration class medical system planning. The National Aeronautics and Space Administration has used PRA since 2011 to inform mission medical system design, but existing tools are designed only for low Earth orbit. An updated PRA tool was needed to assist with exploration class missions.METHODS: A team of medical experts with a wide range of expertise and experience, including Space Medicine, was assembled to build capability and resource tables for the new PRA tool. This team met over 8 mo and used practice guidelines, literature, and experience to build capability and resource tables (CRTs) for each condition in the new PRA tool database.RESULTS: This process led to CRTs for each condition and a total of 617 distinct capabilities and 839 discrete resources.CONCLUSION: The CRT method is an effective way to translate medical practice guidelines into capabilities and resources usable by PRA tools for exploration class medical system planning. This same method may be used in commercial space ventures and in other applications in which medical predictive analytics are informative.Levin DR, Nelson AM, Zahner C, Stratton ER, Anderson A, Steller J. A method to determine capabilities and resources for spacecraft medical systems. Aerosp Med Hum Perform. 2024; 95(7):403-408.

Literature review of spinal hematoma case reports: causes and outcomes in pediatric, obstetric, neuraxial and pain medicine cases.

BACKGROUND: The risk of spinal epidural hematoma (SEH) has been described in the literature but the impact in various patient populations has not been assessed in the same study. We identified the risk factors for SEH and calculated the OR for recovery in the pediatric, adult and obstetric (OB) patients based on the degree of neurological deficit before surgery. METHODS: Adult non-OB cases were categorized whether they were on anticoagulants or not; SEH was related to neuraxial or pain procedure; or whether there was adherence to the American Society of Regional Anesthesia (ASRA) guidelines. Eligible cases were identified through PubMed and Embase searches in the English literature from 1954 to July 2022. RESULTS: A total of 940 cases were evaluated. In the pediatric cases, SEH was typically spontaneous, related to coagulopathy or athletic trauma. OB cases were spontaneous or related to neuraxial injections. Among adults on anticoagulant(s), SEH was mostly spontaneous with no related etiology or related to neuraxial procedure. SEH occurred despite adherence to the ASRA guidelines. Among non-OB adults not on anticoagulants, SEH was due to trauma, neuraxial injections, surgery or other causes. Neurological recovery was related to the degree of neurological deficit before surgery. CONCLUSIONS: Our data show a preponderance of spontaneous SEH in all patient populations. SEH developed even though the ASRA guidelines were followed, especially in patients on multiple anticoagulants. Patients with less impairment prior to surgery had a higher likelihood of complete recovery, regardless of the interval between surgery and onset of symptoms.

Enhancing Standard of Care Chemotherapy Efficacy Using DNA-Dependent Protein Kinase (DNA-PK) Inhibition in Preclinical Models of Ewing Sarcoma.

Disruption of DNA damage repair via impaired homologous recombination is characteristic of Ewing sarcoma (EWS) cells. We hypothesize that this disruption results in increased reliance on nonhomologous end joining to repair DNA damage. In this study, we investigated if pharmacologic inhibition of the enzyme responsible for nonhomologous end joining, the DNA-PK holoenzyme, alters the response of EWS cells to genotoxic standard of care chemotherapy. We used analyses of cell viability and proliferation to investigate the effects of clinical DNA-PK inhibitors (DNA-PKi) in combination with six therapeutic or experimental agents for EWS. We performed calculations of synergy using the Loewe additivity model. Immunoblotting evaluated treatment effects on DNA-PK, DNA damage, and apoptosis. Flow cytometric analyses evaluated effects on cell cycle and fate. We used orthotopic xenograft models to interrogate tolerability, drug mechanism, and efficacy in vivo. DNA-PKi demonstrated on-target activity, reducing phosphorylated DNA-PK levels in EWS cells. DNA-PKi sensitized EWS cell lines to agents that function as topoisomerase 2 (TOP2) poisons and enhanced the DNA damage induced by TOP2 poisons. Nanomolar concentrations of single-agent TOP2 poisons induced G2M arrest and little apoptotic response while adding DNA-PKi-mediated apoptosis. In vivo, the combination of AZD7648 and etoposide had limited tolerability but resulted in enhanced DNA damage, apoptosis, and EWS tumor shrinkage. The combination of DNA-PKi with standard of care TOP2 poisons in EWS models is synergistic, enhances DNA damage and cell death, and may form the basis of a promising future therapeutic strategy for EWS.

Use of corticosteroids for adult chronic pain interventions: sympathetic and peripheral nerve blocks, trigger point injections - guidelines from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, the American Society of Interventional Pain Physicians, the International Pain and Spine Intervention Society, and the North American Spine Society.

BACKGROUND: There is potential for adverse events from corticosteroid injections, including increase in blood glucose, decrease in bone mineral density and suppression of the hypothalamic-pituitary axis. Published studies note that doses lower than those commonly injected provide similar benefit. METHODS: Development of the practice guideline was approved by the Board of Directors of American Society of Regional Anesthesia and Pain Medicine with several other societies agreeing to participate. The scope of guidelines was agreed on to include safety of the injection technique (landmark-guided, ultrasound or radiology-aided injections); effect of the addition of the corticosteroid on the efficacy of the injectate (local anesthetic or saline); and adverse events related to the injection. Based on preliminary discussions, it was decided to structure the topics into three separate guidelines as follows: (1) sympathetic, peripheral nerve blocks and trigger point injections; (2) joints; and (3) neuraxial, facet, sacroiliac joints and related topics (vaccine and anticoagulants). Experts were assigned topics to perform a comprehensive review of the literature and to draft statements and recommendations, which were refined and voted for consensus (≥75% agreement) using a modified Delphi process. The United States Preventive Services Task Force grading of evidence and strength of recommendation was followed. RESULTS: This guideline deals with the use and safety of corticosteroid injections for sympathetic, peripheral nerve blocks and trigger point injections for adult chronic pain conditions. All the statements and recommendations were approved by all participants after four rounds of discussion. The Practice Guidelines Committees and Board of Directors of the participating societies also approved all the statements and recommendations. The safety of some procedures, including stellate blocks, lower extremity peripheral nerve blocks and some sites of trigger point injections, is improved by imaging guidance. The addition of non-particulate corticosteroid to the local anesthetic is beneficial in cluster headaches but not in other types of headaches. Corticosteroid may provide additional benefit in transverse abdominal plane blocks and ilioinguinal/iliohypogastric nerve blocks in postherniorrhaphy pain but there is no evidence for pudendal nerve blocks. There is minimal benefit for the use of corticosteroids in trigger point injections. CONCLUSIONS: In this practice guideline, we provided recommendations on the use of corticosteroids in sympathetic blocks, peripheral nerve blocks, and trigger point injections to assist clinicians in making informed decisions.

Daring discourse: artificial intelligence in pain medicine, opportunities and challenges.

Artificial intelligence (AI) tools are currently expanding their influence within healthcare. For pain clinics, unfettered introduction of AI may cause concern in both patients and healthcare teams. Much of the concern stems from the lack of community standards and understanding of how the tools and algorithms function. Data literacy and understanding can be challenging even for experienced healthcare providers as these topics are not incorporated into standard clinical education pathways. Another reasonable concern involves the potential for encoding bias in healthcare screening and treatment using faulty algorithms. And yet, the massive volume of data generated by healthcare encounters is increasingly challenging for healthcare teams to navigate and will require an intervention to make the medical record manageable in the future. AI approaches that lighten the workload and support clinical decision-making may provide a solution to the ever-increasing menial tasks involved in clinical care. The potential for pain providers to have higher-quality connections with their patients and manage multiple complex data sources might balance the understandable concerns around data quality and decision-making that accompany introduction of AI. As a specialty, pain medicine will need to establish thoughtful and intentionally integrated AI tools to help clinicians navigate the changing landscape of patient care.

Block Time: A Multispecialty Systematic Review of Efficacy and Safety of Ultrasound-guided Upper Extremity Nerve Blocks.

INTRODUCTION: Ultrasound-guided peripheral nerve blockade is a common pain management strategy to decrease perioperative pain and opioid/general anesthetic use. In this article our goal was to systematically review publications supporting upper extremity nerve blocks distal to the brachial plexus. We assessed the efficacy and safety of median, ulnar, radial, suprascapular, and axillary nerve blocks by reviewing previous studies. METHODS: We searched MEDLINE and Embase databases to capture studies investigating these nerve blocks across all specialties. We screened titles and abstracts according to agreed-upon inclusion/exclusion criteria. We then conducted a hand search of references to identify studies not found in the initial search strategy. RESULTS: We included 20 studies with 1,273 enrolled patients in qualitative analysis. Both anesthesiology (12, 60%) and emergency medicine (5, 25%) specialties have evidence of safe and effective use of radial, ulnar, median, suprascapular, and axillary blocks for numerous clinical applications. Recently, multiple randomized controlled trials show suprascapular nerve blocks may result in lower pain scores in patients with shoulder dislocations and rotator cuff injuries, as well as in patients undergoing anesthesia for shoulder surgery. CONCLUSION: Distal upper extremity nerve blocks under ultrasound guidance may be safe, practical strategies for both acute and chronic pain in perioperative, emergent, and outpatient settings. These blocks provide accessible, opioid-sparing pain management, and their use across multiple specialties may be expanded with increased procedural education of trainees.

Serratus anterior plane block as a bridge to outpatient management of severe rib fractures: a case report.

Rib fractures account for a significant number of emergency department visits each year. A patient's disposition often depends on the severity of rib fractures, comorbidities, and ability to achieve adequate analgesia. We present a 44-year-old male patient with severe pain secondary to rib fractures. The initial disposition was to admit for pain control. However, upon performing a serratus anterior plane block, patient was functionally appropriate for discharge with proper return precautions. Serratus anterior plane block is within the skillset of the emergency physician and can be used to achieve analgesia for rib fractures without the sedative and respiratory depressive effects associated with opioids.