Spinal Cord Stimulation for Neuropathic Pain Treatment in Brachial Plexus Avulsions: A Literature Review and Report of Two Cases.

BACKGROUND: At least 50% of individuals who suffer a brachial plexus avulsion (BPA) will develop chronic pain, frequently more debilitating than their functional limitations. Similar to other neuropathic pain states, BPA pain is often refractory to pharmacological agents. Despite spinal cord stimulation (SCS) first being used for BPA in 1974, there have been no published literature reviews examining the current evidence of SCS for the treatment of neuropathic pain following BPA. In addition to a clinical review of the literature for this indication, we also share our experience with high-frequency SCS (HF-SCS) for BPA-related pain. METHODS: MEDLINE and EMBASE databases were searched. All published articles including at least one BPA individual treated with SCS for pain treatment were included. RESULTS: The initial search identified 288 articles, of which 13 met inclusion criteria for a total of 41 patients. These patients were primarily male and underwent SCS with reported improved pain scores. CASE REPORTS: HF-SCS leads were percutaneously placed in two male patients who suffered BPA from traumatic injuries. At follow-ups of 13 and eight months, respectively, both patients continued to report an improvement in their pain. CONCLUSIONS: Despite published reports showing benefit for pain control in patients with BPA, the overall low quality, retrospective evidence included in this review highlights the need for a rigorous prospective study to further address this indication.

Viral Vector-Mediated Gene Transfer of Glutamic Acid Decarboxylase for Chronic Pain Treatment: A Literature Review.

Chronic pain is long-lasting nociceptive state, impairing the patient's quality of life. Existing analgesics are generally not effective in the treatment of chronic pain, some of which such as opioids have the risk of tolerance/dependence and overdose death with higher daily opioid doses for increasing analgesic effect. Opioid use disorders have already reached an epidemic level in the United States; therefore, nonopioid analgesic approach and/or use of nonpharmacologic interventions will be employed with increasing frequency. Viral vector-mediated gene therapy is promising in clinical trials in the nervous system diseases. Glutamic acid decarboxylase (GAD) enzyme, a key enzyme in biosynthesis of γ-aminobutyric acid (GABA), plays an important role in analgesic mechanism. In the literature review, we used PubMed and bioRxiv to search the studies, and the eligible criteria include (1) article written in English, (2) use of viral vectors expressing GAD67 or GAD65, and (3) preclinical pain models. We identified 13 eligible original research articles, in which the pain models include nerve injury, HIV-related pain, painful diabetic neuropathy, and formalin test. GAD expressed by the viral vectors from all the reports produced antinociceptive effects. Restoring GABA systems is a promising therapeutic strategy for chronic pain, which provides evidence for the clinical trial of gene therapy for pain in the near future.

Pre-Injection of Small Interfering RNA (siRNA) Promotes c-Jun Gene Silencing and Decreases the Survival Rate of Axotomy-Injured Spinal Motoneurons in Adult Mice.

Brachial plexus injury is a common clinical peripheral nerve trauma. A series of genes in motoneurons were activated in the corresponding segments of the spinal cord after brachial plexus roots axotomy. The spatial and temporal expression of these genes directly affects the speed of motoneuron axon regeneration and precise target organ reinnervation. In a previous study, we observed the overexpression of c-Jun in motoneurons of the spinal cord ventral horn after brachial plexus injury in rats. However, the relevance of c-Jun expression with respect to the fate of axotomy-induced branchial plexus injury in adult mice remains unknown. In the present study, we explored the function of c-Jun in motoneuron recovery after axotomy. We pre-injected small interfering RNA (siRNA) to knockdown c-Jun expression in mice and examined the effects of the overexpression of c-Jun in motoneurons after the axotomy of the brachial plexus in vivo. Axotomy induced c-Jun overexpression in the ventral horn motoneurons of adult mice from 3 to 14 days after injury. In addition, the pre-injection of siRNA transiently inhibited c-Jun expression and decreased the survival rate of axotomy-injured motoneurons. These findings indicate that the axotomy-induced overexpression of c-Jun plays an important role in the survival of ventral horn motoneurons in adult mice. In addition, the pre-injection of c-Jun siRNA through the brachial plexus stem effectively adjusts c-Jun gene expression at the ipsilateral side.

Transitory spinal accessory nerve injury following post-fossa surgery for Chiari malformation.

We report the case of a young patient with a transient transitory spinal accessory injury after foramen magnum decompression for Chiari malformation. The pathophysiology and the possible mechanisms of injury are highlighted and discussed. Some tips to avoid this potentially severe iatrogenic complication are provided.

Complete Spinal Accessory Nerve Palsy From Carrying Climbing Gear.

We report an unusual case of spinal accessory nerve palsy sustained while transporting climbing gear. Spinal accessory nerve injury is commonly a result of iatrogenic surgical trauma during lymph node excision. This particular nerve is less frequently injured by blunt trauma. The case reported here results from compression of the spinal accessory nerve for a sustained period-that is, carrying a load over the shoulder using a single nylon rope for 2.5 hours. This highlights the importance of using proper load-carrying equipment to distribute weight over a greater surface area to avoid nerve compression in the posterior triangle of the neck. The signs and symptoms of spinal accessory nerve palsy and its etiology are discussed. This report is particularly relevant to individuals involved in mountaineering and rock climbing but can be extended to anyone carrying a load with a strap over one shoulder and across the body.

Maximizing shoulder function after accessory nerve injury and neck dissection surgery: A multicenter randomized controlled trial.

BACKGROUND: Shoulder pain and dysfunction after neck dissection may result from injury to the accessory nerve. The effect of early physical therapy in the form of intensive scapular strengthening exercises is unknown. METHODS: A total of 59 neck dissection participants were prospectively recruited for this study. Participants were randomly assigned to either the intervention group (n = 32), consisting of progressive scapular strengthening exercises for 12 weeks, or the control group (n = 29). Blinded assessment occurred at baseline, and at 3, 6, and 12 months. RESULTS: Three-month data were collected on 52 participants/53 shoulders. Per-protocol analysis demonstrated that the intervention group had statistically significantly higher active shoulder abduction at 3 months compared to the control group (+26.6°; 95% confidence interval [CI] 7.28-45.95; p = .007). CONCLUSION: The intervention is a favorable treatment for maximizing shoulder abduction in the short term. The effect of the intervention compared to usual care is uncertain in the longer term.

Efectos de la técnica de arcos botantes para la abertura de la sutura occipitomastoidea en la cervicalgia mecánica / Effects of flying buttresses for the opening of the occipitomastoid suture in mechanical neck pain

Introducción: La cervicalgia mecánica (CM) podría considerarse un problema de salud pública, ya que afecta a casi la mitad de la población en algún momento de su vida. En el 14% de la población, tiene una duración de 6 meses o más, provocando limitaciones laborales, en las actividades de la vida diaria así y de ocio. Objetivo: Analizar los efectos inmediatos de la técnica con arcos botantes (TAB) para la abertura de la sutura occipitomastoidea (OM), realizada bilateralmente, sobre la amplitud articular cervical, el umbral de dolor a la presión (UDP) y la intensidad del dolor. Material y Métodos: Estudio experimental, controlado, aleatorizado, doble ciego. Treinta (n=30) sujetos con CM, distribuidos aleatoriamente en dos grupos, Grupo Experimental (GE)(n=15) que recibió la TAB bilateralmente, y Grupo Control (GC) (n=15) que no recibió ninguna intervención. En ambos grupos se evaluaron (antes y después), la amplitud articular cervical, el UDP, los Puntos gatillo de Trapecios superiores y Escalenos anteriores (algómetría), y la intensidad del dolor en reposo y con cada movimiento cervical mediante una escala numérica del dolor (END). Resultados: El GE presenta mejoras estadísticamente significativas para las variables algométricas del trapecio superior derecho(p=0,033),trapecio superior izquierdo(p=0,03), la OM izquierda(p=0,003), el escaleno izquierdo(p=0,043), la amplitud de movimiento en rotación izquierda(p=0,04) y la intensidad del dolor a la rotación izquierda (p=0,013). Observamos tendencia a la significación estadística de la amplitud del movimiento de lateroflexión izquierda (p=0,056). Conclusiones: La técnica con arcos botantes para la abertura de la OM, aplicada en pacientes con CMC, aumenta el UDP en los músculol s trapecios, escaleno izquierdo y la sutura OM izquierda, la amplitud de movilidad y disminuye el dolor, durante la rotación cervical izquierda (AU)

Introduction: Mechanical neck pain (CM) could be considered a public health problem, affecting almost half of the population at some point in their lives. In 14% of the population, it has a duration of 6 months or more, causing labor limitations in activities of daily life and leisure. Objective: To analyze the immediate effects of the technique with flying buttresses (TFB) for the opening of the occipitomastoid (OM) suture, conducted bilaterally on the cervical joint extent, the pain pressure threshold (UDP) and the pain intensity. Material and methods: Experimental study, controlled, randomized, double-blind. Thirty (n = 30) subjects with CM, randomized into two groups: Experimental Group (GE) (n = 15) bilaterally received the TAB and Control Group (CG) (n = 15) that did not receive any intervention. In both groups, the cervical joint amplitude were evaluated (before and after), as well as the UDP, the trigger points of the higher trapezoids and anterior scalenes (algometry) and pain intensity at rest and with each cervical movement using a numerical pain scale (END). Results: The GE introduces significant improvements for algometrical variables of the right upper trapezius (p = 0.033), left upper trapezius (p = 0.03), the left OM (p = 0.003), the left scalene (p = 0.043), the range of motion in left rotation (p = 0.04) and pain intensity in left rotation (p = 0.013). We observed a trend towards statistical significance of the range of left sidebending (p = 0.056). Conclusions: The flying buttress technique for the opening of OM, applied in patients with CMC, increases the UDP in the trapezius muscles, left scalene and left OM suture, range of motion and decreases pain during left cervical rotation (AU)

Scapular muscle exercises following neck dissection surgery for head and neck cancer: a comparative electromyographic study.

BACKGROUND: Shoulder pain and dysfunction can occur following neck dissection surgery for cancer. These conditions often are due to accessory nerve injury. Such an injury leads to trapezius muscle weakness, which, in turn, alters scapular biomechanics. OBJECTIVE: The aim of this study was to assess which strengthening exercises incur the highest dynamic activity of affected trapezius and accessory scapular muscles in patients with accessory nerve dysfunction compared with their unaffected side. DESIGN: A comparative design was utilized for this study. METHODS: The study was conducted in a physical therapy department. Ten participants who had undergone neck dissection surgery for cancer and whose operated side demonstrated clinical signs of accessory nerve injury were recruited. Surface electromyographic activity of the upper trapezius, middle trapezius, rhomboid major, and serratus anterior muscles on the affected side was compared dynamically with that of the unaffected side during 7 scapular strengthening exercises. RESULTS: Electromyographic activity of the upper and middle trapezius muscles of the affected side was lower than that of the unaffected side. The neck dissection side affected by surgery demonstrated higher levels of upper and middle trapezius muscle activity during exercises involving overhead movement. The rhomboid and serratus anterior muscles of the affected side demonstrated higher levels of activity compared with the unaffected side. LIMITATIONS: Exercises were repeated 3 times on one occasion. Muscle activation under conditions of increased exercise dosage should be inferred with caution. CONCLUSIONS: Overhead exercises are associated with higher levels of trapezius muscle activity in patients with accessory nerve injury following neck dissection surgery. However, pain and correct scapular form must be carefully monitored in this patient group during exercises. Rhomboid and serratus anterior accessory muscles may have a compensatory role, and this role should be considered during rehabilitation.