State of the science review: Advances in pain management in wounded service members over a decade at war

A Systematic Review of Chronic Pain Management Interventions Among Veterans of Recent Wars and Armed Conflicts

OBJECTIVES

To identify chronic pain management strategies aimed to reduce pain intensity and enhance functional outcomes in veterans of wars and armed conflict.

DESIGN

Systematic review without meta-analysis.

DATA SOURCES

Key words "chronic pain," "veterans," and "injuries" were used to search for articles in the MEDLINE, CINAHL, APA PsycInfo, and Embase databases. Articles published in English between 2000 and 2023 were included.

REVIEW/ANALYSIS METHODS

A systematic literature search was conducted in June 2020, updated in April 2023, and managed using Covidence review software. Inclusion criteria focused on combat-injured veterans with chronic pain, excluding nonveterans and civilians treated for acute or chronic pain. Data from included studies were extracted, summarized, and critically appraised using the 2018 Mixed Methods Appraisal Tool. This review is registered with PROSPERO (CRD42020207435).

RESULTS

Fourteen studies met the inclusion criteria, with 10 of them supporting nonpharmacological approaches for managing chronic pain among veterans of armed conflicts and wars. Interventions included psychological/behavioral therapies, peer support, biofeedback training via telephone-based therapy, manual therapy, yoga, cognitive processing therapy, cognitive-behavioral therapy, and social and community integration to reduce pain intensity and enhance functional outcomes.

CONCLUSION

Nonpharmacological treatments for chronic pain have increased in recent years, a shift from earlier reliance on pharmacological treatments. More evidence from randomized controlled trials on the benefits of combined pain interventions could improve pain management of veterans with complex care needs.

Differential Pain Presentations Observed Across Post-Traumatic Stress Disorder Symptom Trajectories After Combat Injury

OBJECTIVE

This study evaluated the association between pain outcomes and post-traumatic stress disorder (PTSD) symptom trajectories after combat-related injury, while adjusting for receipt of regional anesthesia (RA) soon after injury.

METHODS

The PTSD symptom trajectories of N = 288 combat-injured service members were examined from within a month of injury up to two-years after. Linear mixed-effects models evaluated the association between PTSD symptom trajectories and average pain and pain interference outcomes while adjusting for receipt of RA during combat casualty care.

RESULTS

Four PTSD trajectories were characterized: resilient, recovering, worsening, and chronic. Differential pain presentations were associated with PTSD symptom trajectories, even after adjusting for receipt of RA. Compared to those with a resilient PTSD symptom trajectory, individuals presenting with chronic PTSD trajectories were estimated to experience average pain scores 2.61 points higher (95% CI: 1.71, 3.14). Participants presenting with worsening (β = 1.42; 95% CI: 0.77, 1.78) and recovering PTSD trajectories (β = 0.65; 95% CI: 0.09, 1.08) were estimated to experience higher average pain scores than participants with resilient PTSD trajectories. Significant differences in pain interference scores were observed across PTSD trajectories. Receiving RA was associated with improved pain up to two years after injury (β =-0.31; 95% CI: -0.90, -0.04), however no statistically significant association was detected between RA and PTSD trajectories.

CONCLUSIONS

PTSD trajectories were associated with greater pain intensity and interference following combat injury even when accounting for receipt of early RA for pain management. These findings underscore the need to jointly assess pain and PTSD symptoms across the trauma care continuum.

Factors That Affect Pain Management in Aeromedical Evacuation: An Ethnographic Approach

BACKGROUND

Pain management is a challenge in the transport setting, but actual factors that influence pain have not been assessed systematically.

OBJECTIVE

To describe the environmental factors and social context that affect pain management in military aeromedical evacuation.

METHODS

Field notes were taken throughout flight, including observational measures of pain, environmental factors, and interactions between the patient and crew. Data collection was completed on 8 missions and 16 patients; common themes were identified that should be considered in the management of pain in aeromedical evacuation.

RESULTS

Communication was a key problem primarily to aircraft noise, the reluctance of patients to speak with crew members while they were wearing headsets, and limited time to assess for pain and provide patient education. Seating and litters appeared to be uncomfortable for ambulatory and litter patients, and preparatory guidance on pain management did not address the stressors of flight or transportation phases. Another compounding factor was the psychological distress, particularly among those leaving a combat zone before the anticipated end of a deployment. Throughout the flight, the military culture of independence, stoicism, and camaraderie also was clearly evident.

CONCLUSIONS

Barriers to communication, comfort, and patient education are well known to transport nurses, but it is important to understand the overall effect they have on the management of pain. Developing solutions to address these factors should be a priority to ensure pain is adequately managed throughout transport.

Local Resiniferatoxin Induces Long-Lasting Analgesia in a Rat Model of Full Thickness Thermal Injury

Objective

Opioid-based analgesics are a major component of the lengthy pain management of burn patients, including military service members, but are problematic due to central nervous system-mediated side effects. Peripheral analgesia via targeted ablation of nociceptive nerve endings that express the transient receptor potential vanilloid channel 1 (TRPV1) may provide an improved approach. We hypothesized that local injection of the TRPV1 agonist resiniferatoxin (RTX) would produce long-lasting analgesia in a rat model of pain associated with burn injury.

Methods

Baseline sensitivities to thermal and mechanical stimuli were measured in male and female Sprague-Dawley rats. Under anesthesia, a 100 °C metal probe was placed on the right hind paw for 30 seconds, and sensitivity was reassessed 72 hours following injury. Rats received RTX (0.25 μg/100 μL; ipl) into the injured hind paw, and sensitivity was reassessed across three weeks. Tissues were collected from a separate group of rats at 24 hours and/or one week post-RTX for pathological analyses of the injured hind paw, dorsal spinal cord c-Fos, and primary afferent neuropeptide immunoreactivity.

Results

Local RTX reversed burn pain behaviors within 24 hours, which lasted through recovery at three weeks. At one week following RTX, decreased c-Fos and primary afferent neuropeptide immunoreactivities were observed in the dorsal horn, while plantar burn pathology was unaltered.

Conclusions

These results indicate that local RTX induces long-lasting analgesia in a rat model of pain associated with burn. While opioids are undesirable in trauma patients due to side effects, RTX may provide valuable long-term, nonopioid analgesia for burn patients.

Musculoskeletal Pain and Headache in the Active Duty Military Population: An Integrative Review

BACKGROUND

Since 2001, the U.S. Armed Forces' training and deployment have greatly increased, escalating the risk of injury and pain-related issues both at home station and deployment environments.

AIMS

This integrative review examines the incidence, prevalence, and risk factors for musculoskeletal pain (MSP) and headaches in active duty (AD) military populations.

METHODS

Peer-reviewed research published between 2001 and 2016 was identified relevant to MSP and headache in AD military personnel using MeSH terms in key biomedical databases. Inclusion criteria were: epidemiological studies examining MSP or headache as primary or secondary outcome; samples that included AD populations; and studies conducted in the theater of operations, at home station, and in military treatment or Veterans Health Administration facilities.

RESULTS

Twenty-six articles met inclusion criteria. Low back pain (LBP) was the most prevalent MSP diagnosis. The incidence of LBP was 40.5 per 1,000 person-years and was comparable to nonmilitary populations. Inflammation and pain from overuse comprised the largest proportion of injury mechanism, accounting for about 82% of all injuries among nondeployed military personnel. The risk of MSP was greater for AD, female, Army, enlisted personnel, and those with greater time in a motor vehicle. Evidence suggests posttraumatic headache, occurring in up to 92% of military personnel who have sustained a mild traumatic brain injury, is associated with chronic daily headaches.

IMPLICATIONS

Nurses must recognize the consequences military service can have on the development of pain. Nurses have an opportunity to positively impact the health and well-being of military and veteran populations through early recognition and treatment of pain.

LINKING EVIDENCE TO ACTION

The findings from this review underscore considerable magnitude of MSP in military personnel and expose modifiable risk factors and potential targets for designing nurse-led interventions to improve pain and symptoms in military subpopulations.

Complexity of the Relationships of Pain, Posttraumatic Stress, and Depression in Combat-Injured Populations: An Integrative Review to Inform Evidence-Based Practice

BACKGROUND

Understanding the complex interrelationships between combat injuries, physical health, and mental health symptoms is critical to addressing the healthcare needs of wounded military personnel and veterans. The relationship between injury characteristics, pain, posttraumatic stress disorder (PTSD), and depression among combat-injured military personnel is unique to modern conflicts and understudied in the nursing literature.

AIM

This integrative review synthesizes clinical presentations and relationships of combat injury, PTSD, depression, and pain in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) United States military service members and veterans.

METHODS

A literature search was conducted using relative key terms across databases to identify peer-reviewed publications between 2001 and 2016 that examined health outcomes of combat-injured persons in OEF and OIF. The quality of evidence was evaluated and results synthesized to examine the association of combat injury as a risk factor for PTSD, the relationship of PTSD and depression pre- and postinjury, and pain management throughout care.

RESULTS

Twenty-two articles were included in this review. Greater injury and pain severity poses risks for developing PTSD following combat injury, while early symptom management lessens risks for PTSD. Depression appears to be both a contributing risk factor to postinjury PTSD, as well as a comorbidity.

LINKING EVIDENCE TO ACTION

Findings demonstrate a compelling need for improvements in standardized assessment of pain and mental health symptoms across transitions in care. This integrative review informs nurse researchers and providers of the clinical characteristics of pain, PTSD, and depression following combat injury and offers implications for future research promoting optimal surveillance of symptoms.

Preemptive perineural bupivacaine attenuates the maintenance of mechanical and cold allodynia in a rat spinal nerve ligation model

Background

Neuropathic pain is evasive to treat once developed, however evidence suggests that local administration of anesthetics near the time of injury reduces the development of neuropathic pain. As abnormal electrical signaling in the damaged nerve contributes to the initiation and maintenance of neuropathic pain, local administration of anesthetics prior to injury may reduce its development. We hypothesized that local treatment with bupivacaine prior to nerve injury in a rat model of spinal nerve ligation (SNL) would attenuate the initiation and/or maintenance of neuropathic pain behaviors.

Methods

On the day prior to SNL, baseline measures of pre-injury mechanical, thermal, and/or cold sensitivity were recorded in adult male Sprague–Dawley rats. Immediately prior to SNL or sham treatment, the right L5 nerve was perineurally bathed in either 0.05 mL bupivacaine (0.5 %) or sterile saline (0.9 %) for 30 min. Mechanical allodynia, thermal hyperalgesia, and/or cold allodynia were then examined at 3, 7, 10, 14 and 21 days following SNL.

Results

Rats exhibited both mechanical and cold allodynia, but not thermal hyperalgesia, within 3 days and up to 21 days post-SNL. No significant pain behaviors were observed in sham controls. Preemptive local bupivacaine significantly attenuated both mechanical and cold allodynia as early as 10 days following SNL compared to saline controls and were not significantly different from sham controls.

Conclusions

These data indicate that local treatment with bupivacaine prior to surgical manipulations that are known to cause nerve damage may protect against the maintenance of chronic neuropathic pain.

Pain management strategies and lessons from the military: A narrative review

BACKGROUND

Wounded soldiers often experience substantial pain, which must be addressed before returning to active duty or civilian life. The United States (US) military has instituted several guidelines and initiatives aimed at improving pain management by providing rapid access to medical care, and developing interdisciplinary multimodal pain management strategies based on outcomes observed both in combat and hospital settings.

OBJECTIVE

To provide a narrative review regarding US military pain management guidelines and initiatives, which may guide improvements in pain management, particularly chronic pain management and prevention, for the general population.

METHODS

A literature review of US military pain management guidelines and initiatives was conducted, with a particular focus on the potential of these guidelines to address shortcomings in chronic pain management in the general population.

DISCUSSION

The application of US military pain management guidelines has been shown to improve pain monitoring, education and relief. In addition, the US military has instituted the development of programs and guidelines to ensure proper use and discourage aberrant behaviours with regard to opioid use, because opioids are regarded as a critical part of acute and chronic pain management schemes. Inadequate pain management, particularly inadequate chronic pain management, remains a major problem for the general population in the US. Application of military strategies for pain management to the general US population may lead to more effective pain management and improved long-term patient outcomes.

Pain management in military trauma

The wounded warrior requires immediate care, and at times, evacuation from injury. Care may be self-regulated, or may require more advanced care under the direction of medics or advanced practitioners, including physicians and surgeons. While survivability is the immediate priority, pain management has become a military initiative, recognizing that poor management of acute pain may lead to the development of chronic pain and post-traumatic stress disorder. This article reviews current initiatives used in current conflict situations, as well as those in continued care following initial stabilization.