High-resolution ultrasound in combat-related peripheral nerve injuries

Combat-related peripheral nerve injuries

Active-duty service members (ADSM) and military Veterans represent a population with increased occupational risk for nerve injuries sustained both during training operations and wartime. Mechanisms of war-related nerve injuries have evolved over time, from the musket ball-related traumas described by S.W. Mitchell to complex blast injuries and toxic exposures sustained during Middle East conflicts in the 21st century. Commonly encountered nerve injury etiologies in this population currently include compression, direct trauma, nutritional deficits, traumatic limb amputation, toxic chemical exposures, or blast-related injuries. Expeditious identification and comprehensive, interdisciplinary treatment of combat-associated neuropathies, as well as prevention of these injuries whenever possible is critical to reduce chronic morbidity and disability for service members and to maintain a well-prepared military. However, diagnosis of a combat-associated nerve injury may be particularly challenging due to comorbid battlefield injuries or delayed presentation of neuropathy from military toxic exposures. Advances in imaging for nerve injury, including MRI and ultrasound, provide useful tools to compliment EMG in establishing a diagnosis of combat-associated nerve injury, particularly in the setting of anatomic disruption or edema. Surgical techniques can improve pain control or restoration of function. In all cases, comprehensive interdisciplinary rehabilitation provides the best framework for optimization of recovery. Further work is needed to prevent combat-associated nerve injuries and promote nerve recovery following injury.

Ballistic peripheral nerve injuries: basic concepts, controversies, and proposal for a management strategy

Ballistic injuries to peripheral nerves are devastating injuries frequently encountered in modern conflicts and civilian trauma centers. Such injuries often produce lifelong morbidity, mainly in the form of function loss and chronic pain. However, their surgical management still poses significant challenges concerning indication, timing, and type of repair, particularly when they are part of high-energy multi-tissue injuries. To help trauma surgeons, this article first presents basic ballistic concepts explaining different types of missile nerve lesions, described using the Sunderland classification, as well as their usual associated injuries. Current controversies regarding their surgical management are then described, including nerve exploration timing and neurolysis's relevance as a treatment option. Finally, based on anecdotal evidence and a literature review, a standardized management strategy for ballistic nerve injuries is proposed. This article emphasizes the importance of early nerve exploration and provides a detailed method for making a diagnosis in both acute and sub-acute periods. Direct suturing with joint flexion is strongly recommended for sciatic nerve defects and any nerve defect of limited size. Conversely, large defects require conventional nerve grafting, and proximal injuries may require nerve transfers, especially at the brachial plexus level. Additionally, combined or early secondary tendon transfers are helpful in certain injuries. Finally, ideal timing for nerve repair is proposed, based on the defect length, associated injuries, and risk of infection, which correlate intimately to the projectile velocity.

Biomimicry in 3D printing design: implications for peripheral nerve regeneration

Nerve guide conduits (NGCs) connect dissected nerve stumps and effectively repair short-range peripheral nerve defects. However, for long-range defects, autografts show better therapeutic effects, despite intrinsic limitations. Recent evidence shows that biomimetic design is essential for high-performance NGCs, and 3D printing is a promising fabricating technique. The current work includes a brief review of the challenges for peripheral nerve regeneration. The authors propose a potential solution using biomimetic 3D-printed NGCs as alternative therapies. The assessment of biomimetic designs includes microarchitecture, mechanical property, electrical conductivity and biologics inclusion. The applications of 3D printing in preparing NGCs and present strategies to improve therapeutic effects are also discussed.

Lower extremity reconstruction for limb salvage and functional restoration - The Combat experience

Evolution in extremity injury treatment often occurs during major conflicts, with lessons learned applied and translated among military and civilian settings. In recent periods of war, improvements in protective equipment, in-theater damage control resuscitation/surgery, delivery of antibiotics locally/systemically, and rapid evacuation to higher levels of medical care capabilities have greatly improved combat casualty survivability rates. Additionally, widespread application of lower extremity tourniquets also has prevented casualties from exsanguination, thus reducing hemorrhagic-related deaths. Secondary to these, a high number of combat casualties suffering lower extremity traumatic injuries have presented for functional limb reconstruction and restoration as well as residual limb care.

Sonographic Evaluation of Peripheral Sciatic Nerve Injury: A Case Study

Traumatic peripheral nerve injury is not a common finding in the general population but is increasingly being recognized and diagnosed in trauma and emergency medicine settings. Peripheral nerve injury can cause temporary or long-term motor and sensory loss, as well as intense pain and disability, if left untreated. The cause of peripheral nerve injury is diverse and often involves soft tissue damage, fractures, and hemorrhage in cases of traumatic injury. Peripheral nerve injury does not always heal spontaneously and, depending on severity, may warrant surgical intervention and repair. Although electrodiagnosic testing and surgical exploration are considered gold standards for peripheral nerve injury, high-resolution sonographic examination supplemented by clinical findings may be of value. The use of sonography demonstrated utility in determining a strategic management timeline and the efficacy of a surgical intervention.

Ultrasound-Guided Needle Localization Wires in Peripheral Nerve Injuries With Long Segmental Defects: Technical Case Report

BACKGROUND AND IMPORTANCE

In cases of severe nerve trauma with significant local soft tissue damage, identification and subsequent repair of nerve stumps can pose a technical challenge. Ultrasound (US) localization in peripheral nerve surgery has recently become popular. We present a case report illustrating the use of needle-wire localization systems to identify proximal and several distal branches of an injured femoral nerve with a large segmental defect in order to illustrate how such techniques can be used to make surgical repair more efficient, particularly with identifying the distal stump(s).

CLINICAL PRESENTATION

We illustrate a case of a 16-yr-old female involved in a traumatic accident that lead to a severe injury of the femoral nerve and artery. The patient presented with a 7.3-cm defect between the proximal and distal aspect of the femoral nerve and its branches, respectively. High-resolution US was used to identify the proximal, large femoral nerve, and 3 distal stumps. By enlisting our musculoskeletal radiology team, we were able to trace distal branches of the femoral nerve and see their target muscles. Three separate US flexible needles were used to locate small muscular branches of the femoral nerve and 1 to locate the proximal stump. Intraoperatively, the localization wires allowed for safe and efficient dissection of proximal and distal nerve stumps in a significantly scarred and edematous plane.

CONCLUSION

US-guided needle-wire localization has shown promise in identifying the distal stumps and minimizing tissue dissection. Preoperative US guidance significantly aided in nerve repair for this severe injury without increasing morbidity.

Nanochannel-Based Poration Drives Benign and Effective Nonviral Gene Delivery to Peripheral Nerve Tissue

While gene and cell therapies have emerged as promising treatment strategies for various neurological conditions, heavy reliance on viral vectors can hamper widespread clinical implementation. Here, the use of tissue nanotransfection as a platform nanotechnology to drive nonviral gene delivery to nerve tissue via nanochannels, in an effective, controlled, and benign manner is explored. TNT facilitates plasmid DNA delivery to the sciatic nerve of mice in a voltage-dependent manner. Compared to standard bulk electroporation (BEP), impairment in toe-spread and pinprick response is not caused by TNT, and has limited to no impact on electrophysiological parameters. BEP, however, induces significant nerve damage and increases macrophage immunoreactivity. TNT is subsequently used to deliver vasculogenic cell therapies to crushed nerves via delivery of reprogramming factor genes Etv2, Foxc2, and Fli1 (EFF). The results indicate the TNT-based delivery of EFF in a sciatic nerve crush model leads to increased vascularity, reduced macrophage infiltration, and improved recovery in electrophysiological parameters compared to crushed nerves that are TNT-treated with sham/empty plasmids. Altogether, the results indicate that TNT can be a powerful platform nanotechnology for localized nonviral gene delivery to nerve tissue, in vivo, and the deployment of reprogramming-based cell therapies for nerve repair/regeneration.

Neuromuscular Ultrasound: Clinical Applications and Diagnostic Values

Advances in high-resolution ultrasound have provided clinicians with unique opportunities to study diseases of the peripheral nervous system. Ultrasound complements the clinical and electrophysiology exam by showing the degree of abnormalities in myopathies, as well as spontaneous muscle activities in motor neuron diseases and other disorders. In experienced hands, ultrasound is more sensitive than MRI in detecting peripheral nerve pathologies. It can also guide needle placement for electromyography exam, therapeutic injections, and muscle biopsy. Ultrasound enhances the ability to detect carpal tunnel syndrome and other focal nerve entrapment, as well as pathological nerve enlargements in genetic and acquired neuropathies. Furthermore, ultrasound can potentially be used as a biomarker for muscular dystrophy and spinal muscular atrophy. The combination of electromyography and ultrasound can increase the diagnostic certainty of amyotrophic lateral sclerosis, aid in the localization of brachial plexus or peripheral nerve trauma and allow for surveillance of nerve tumor progression in neurofibromatosis. Potential limitations of ultrasound include an inability to image deeper structures, with lower sensitivities in detecting neuromuscular diseases in young children and those with mitochondrial myopathies, due to subtle changes or early phase of the disease. As well, its utility in detecting critical illness neuromyopathy remains unclear. This review will focus on the clinical applications of neuromuscular ultrasound. The diagnostic values of ultrasound for screening of myopathies, neuropathies, and motor neuron diseases will be presented.

Neuromuscular Ultrasound: A New Tool in Your Toolbox

Neuromuscular ultrasound is a rapidly evolving technique for diagnosing, monitoring and facilitating treatment of patients with muscle and nerve disorders. It is a portable point-of-care technology that is non-invasive, painless and without ionizing radiation. Ultrasound can visualize muscle texture alterations indicating dystrophy or denervation, changes in size and anatomic continuity of nerve fascicles, and its dynamic imaging capabilities allow capturing of contractions and fasciculations. Ultrasound can also provide real-time guidance for needle placement, and can sometimes make a diagnosis when electromyography is not tolerated or not informative anymore. This review will focus on the technical and practical aspects of ultrasound as an imaging technique for muscles and nerves. It will discuss basic imaging principles, hardware and software setup, and provide examples of ultrasound use for visualizing muscle and nerve abnormalities with accuracy and confidence. The review is intended as a practical "how-to" guide to get started with neuromuscular ultrasound in daily practice.

Is heterotopic ossification getting nervous?: The role of the peripheral nervous system in heterotopic ossification

Heterotopic ossification (HO), or de novo bone formation in soft tissue, is often observed following traumatic injury. Recent studies suggest that peripheral nerves may play a key functional role in this process. The results supporting a neurological basis for HO are examined in this article. Evidence supports the fact that BMPs released from bone matrix possess the capacity to induce HO. However, the process cannot be recapitulated using recombinant proteins without extremely high doses suggesting other components are required for this process. Study of injuries that increase risk for HO, i.e. amputation, hip replacement, elbow fracture, burn, and CNS injury suggests that a likely candidate is traumatic injury of adjacent peripheral nerves. Recent studies suggest neuroinflammation may play a key functional role, by its ability to open the blood-nerve barrier (BNB). Barrier opening is characterized by a change in permeability and is experimentally assessed by the ability of Evans blue dye to enter the endoneurium of peripheral nerves. A combination of BMP and barrier opening is required to activate bone progenitors in the endoneurial compartment. This process is referred to as "neurogenic HO".

Expert consensus on the evaluation and diagnosis of combat injuries of the Chinese People's Liberation Army

The accurate assessment and diagnosis of combat injuries are the basis for triage and treatment of combat casualties. A consensus on the assessment and diagnosis of combat injuries was made and discussed at the second annual meeting of the Professional Committee on Disaster Medicine of the Chinese People's Liberation Army (PLA). In this consensus agreement, the massive hemorrhage, airway, respiration, circulation and hypothermia (MARCH) algorithm, which is a simple triage and rapid treatment and field triage score, was recommended to assess combat casualties during the first-aid stage, whereas the abbreviated scoring method for combat casualty and the MARCH algorithm were recommended to assess combat casualties in level II facilities. In level III facilities, combined measures, including a history inquiry, thorough physical examination, laboratory examination, X-ray, and ultrasound examination, were recommended for the diagnosis of combat casualties. In addition, corresponding methods were recommended for the recognition of casualties needing massive transfusions, assessment of firearm wounds, evaluation of mangled extremities, and assessment of injury severity in this consensus.