A review of biomechanics of the central nervous system--part II: spinal cord strains from postural loads.

OBJECTIVE: To review spinal cord strains arising from postural loads. DATA COLLECTION: A hand search of available reference texts and a computer search of literature from the Indexed Medicus sources were collected, with special emphasis placed on spinal cord strains caused by various postural rotations and translations of the skull, thorax, and pelvis RESULTS: All spinal postures will deform the neural elements within the spinal canal. Flexion causes the largest canal length changes and, hence, the largest nervous system deformations. Neural tissue strains depend on the spinal level, the spinal movement generated, and the sequence of movements when more than one spinal area is moved. CONCLUSIONS: Rotations of the global postural components (head, thoracic cage, pelvis, and legs) cause stresses and strains in the central nervous system and peripheral nervous system. Translations of the skull, thorax, and pelvis, as well as combined postural loads, need to be studied for their effects on the spinal canal and neural tissue deformations. Flexion of any part of the spinal column may generate axial tension in the entire cord and nerve roots. Slight extension is the preferred position of the spine as far as reducing the magnitude of mechanical stresses and strains in the central nervous system is concerned.     

A review of biomechanics of the central nervous system--Part I: spinal canal deformations resulting from changes in posture.

OBJECTIVE: To discuss how the spinal cord deforms as a result of changes in posture or biomechanical alterations of the spine. DATA COLLECTION: A hand search of available reference texts and a computer search of literature from the Index Medicus sources were collected, with special emphasis placed on spinal canal changes caused by various postural rotations and translations of the skull, thorax, and pelvis. RESULTS: All spinal postures will deform the spinal canal. Flexion causes a small increase in canal diameter and volume as the vertebral lamina are separated. Extension causes a small decrease in canal diameter and volume as the vertebral lamina are approximated. Lateral bending and axial rotation cause insignificant changes in spinal canal diameter and volume in cases without stenosis. CONCLUSIONS: Rotations of the global postural components, head, thoracic cage, and pelvis cause changes in the diameter of the spinal canal and intervertebral foramen. These changes are generally a reduction of less than 1.5 mm in extension, compared with a small increase in flexion of approximately 1 mm. These small changes do not account for the clinical observation of patients having increased neurologic signs and symptoms in flexion.     

The effects of spinal mobilizations on the sympathetic nervous system: A systematic review

The activity of the sympathetic nervous system is of importance to manual therapists, since the experience of pain is associated with sympathetic activity. There has been little exploration into the effects of mobilizing vertebral segments below the cervical spine. In addition to this, a synthesis of the evidence for changes in sympathetic outcome measures has not been completed.The primary aim of this review was to investigate the effects of spinal mobilizations compared to a control or placebo on sympathetic outcome measures. The secondary aim was to establish the level of change, either excitatory or inhibitory, in sympathetic outcome measures. Five electronic databases (Ovid Medline, Embase, AMED, PEDro, and the Cochrane library; from database inception to May 2012) were searched for randomized controlled trials. Two independent raters applied inclusion criteria and rated studies for methodological quality. Seven studies met the inclusion criteria.All studies demonstrated a consistent increase in sympathetic outcome measures, indicative of sympathetic excitation, irrespective of the segments mobilized. Synthesis of the results established strong evidence (multiple high-quality randomised controlled trials (RCTs) for a positive change in skin conductance, respiratory rate, blood pressure, and heart rate among the healthy population. As only one study investigated changes in a symptomatic population, there was limited evidence (one RCT) for an increase in skin conductance and decrease in skin temperature. Evidence from this systematic review supports a sympatho-excitatory response to spinal mobilizations irrespective of the segment mobilized.     

Astrocytes in the central nervous system and their functions in health and disease: A review

Astrocytes are key cells in the central nervous system. They are involved in many important functions under physiological and pathological conditions. As part of neuroglia, they have been recognised as cellular elements in their own right. The name astrocyte was first proposed by Mihaly von Lenhossek in 1895 because of the finely branched processes and star-like appearance of these particular cells. As early as the late 19^th and early 20^th centuries, Ramon y Cajal and Camillo Golgi had noted that although astrocytes have stellate features, their morphology is extremely diverse. Modern research has confirmed the morphological diversity of astrocytes both in vitro and in vivo and their complex, specific, and important roles in the central nervous system. In this review, the functions of astrocytes and their roles are described.     

Chronic pain and spinal cord injury: review and comment.

The problem of severe chronic pain following spinal cord injury (SCI) has been well delineated for many years. However, progress has been slow in determining which treatment procedures work for which type of SCI pain in a particular individual at a particular time. Reasons for such slow progress include the low incidence and prevalence of SCI making large series of patients unavailable for trials in many centers. Lack of a widely accepted SCI pain classification scheme has also limited the comparability of similar interventions carried out by different investigators. Design limitations of many existing studies that can be remedied in future investigations are reviewed. Finally, discussion of two conceptual models of SCI pain is presented and an argument raised for the utility of both.     

Selected neurologic complications in the patient with cancer. Brain metastases and spinal cord compression

Nurses play a key role in care of patients with brain metastases and spinal cord compression. Care of this patient population is unique because the skills and knowledge of medical-surgical, neurologic, oncologic, and critical care nurses are required. With the wide variability among patients, a highly individualized care plan is necessary to meet the tremendous challenges of caring for patients with metastatic central nervous system disease.     

Malignant spinal cord tumors: a review and case presentation.

Since malignant spinal cord tumors constitute such a small percentage of spinal cord lesions, nurses may be unaware of the challenging needs of this group of patients. Often young and previously healthy, these people face a rapidly progressive and dismal disease course. Presentation and complaints are related to the location and growth rate of the tumor. Treatment is geared to debulking the tumor mass and preventing its spread. This article discusses the pathophysiology, signs and symptoms, medical management and nursing implications for the patient diagnosed with a malignant spinal cord tumor. A case presentation including examples of nursing diagnosis and interventions follows.     

MR imaging of cerebrospinal fluid flow and spinal cord motion in neurologic disorders of the spine.

In summary, MR imaging of CSF and cord motion helps to evaluate diseases affecting cord and CSF motion and to identify the specific pathophysiology involved. A number of significant points have been made. First, MR imaging flow studies can be useful in evaluating CSF spaces and cystic diseases. Second, longitudinal and transverse motions occur in the spinal cord and CSF. Traveling wave motion occurs along the length of the spinal cord. Third, spinal cord tethering is associated with decreased cord velocity and loss of cord displacement at tethering site. Decreased transverse velocities occur with lateral cord tethering to the spinal canal. Fourth, in spinal dysraphism, longitudinal cord velocity is decreased by tethering, and is normal in asymptomatic patients with low conus. Normal cord motion helps to rule out possible tethering in symptomatic dysraphism with hydromyelia. Fifth, in acquired and nonmyelodysplastic symptomatic tethering, spinal cord motion is decreased. Sixth, in symptomatic cord compression, CSF flow and cord motion decrease, but recover after surgical decompression and after compensatory atrophy. Seventh, in asymptomatic spinal stenosis, cord motion is normal or increased. Diffuse spinal stenosis with cord atrophy leads to diffuse cord acceleration and prolonged cord caudal velocity, possibly related to the loss of the transverse mobility of the cord. Finally, focal spinal stenosis leads to focal dynamic cord deformation and can be associated with prominent intramedullary deformations. When compression is severe or symptomatic, cord motion is significantly decreased. Postoperative cases demonstrate good recovery of cord and CSF motion, unless compression or obstruction is still present.     

Locomotor training: as a treatment of spinal cord injury and in the progression of neurologic rehabilitation

Harkema SJ, Hillyer J, Schmidt-Read M, Ardolino E, Sisto SA, Behrman AL. Locomotor training: as a treatment of spinal cord injury and in the progression of neurologic rehabilitation. Scientists, clinicians, administrators, individuals with spinal cord injury (SCI), and caregivers seek a common goal: to improve the outlook and general expectations of the adults and children living with neurologic injury. Important strides have already been accomplished; in fact, some have labeled the changes in neurologic rehabilitation a "paradigm shift." Not only do we recognize the potential of the damaged nervous system, but we also see that "recovery" can and should be valued and defined broadly. Quality-of-life measures and the individual's sense of accomplishment and well-being are now considered important factors. The ongoing challenge from research to clinical translation is the fine line between scientific uncertainty (ie, the tenet that nothing is ever proven) and the necessary burden of proof required by the clinical community. We review the current state of a specific SCI rehabilitation intervention (locomotor training), which has been shown to be efficacious although thoroughly debated, and summarize the findings from a multicenter collaboration, the Christopher and Dana Reeve Foundation's NeuroRecovery Network.     

Strategies for spinal cord repair after injury: A review of the literature and information

IntroductionThanks to the Internet, we can now have access to more information about spinal cord repair. Spinal cord injured (SCI) patients request more information and hospitals offer specific spinal cord repair medical consultations.ObjectiveProvide practical and relevant elements to physicians and other healthcare professionals involved in the care of SCI patients in order to provide adequate answers to their questions.MethodOur literature review was based on English and French publications indexed in PubMed and the main Internet websites dedicated to spinal cord repair.ResultsA wide array of research possibilities including notions of anatomy, physiology, biology, anatomopathology and spinal cord imaging is available for the global care of the SCI patient. Prevention and repair strategies (regeneration, transplant, stem cells, gene therapy, biomaterials, using sublesional uninjured spinal tissue, electrical stimulation, brain/computer interface, etc.) for the injured spinal cord are under development. It is necessary to detail the studies conducted and define the limits of these new strategies and benchmark them to the realistic medical and rehabilitation care available to these patients.ConclusionResearch is quickly progressing and clinical trials will be developed in the near future. They will have to answer to strict methodological and ethical guidelines. They will first be designed for a small number of patients. The results will probably be fragmented and progress will be made through different successive steps.     

Male infertility and erectile dysfunction in spinal cord injury: a review.

OBJECTIVE: To review the pathophysiology, evaluation, and management of erectile dysfunction and infertility in spinal cord injury (SCI). STUDY SELECTIONS: Studies that covered various treatment options and their contraindications, complications, or side effects, including sildenafil (Viagra), intracavernosal injection therapy, topical medications and a urethral delivery system, a vacuum erection device, and penile prostheses. Other studies covered the effects of SCI on reproduction: spermatogenesis and testicular function, and seminal constituents. In addition, assisted reproductive techniques were compared: external vibratory stimulation, electroejaculation, testicular sperm aspiration, and intracytoplasmic sperm injection. CONCLUSION: Goal-directed therapy is the mainstay of treatment of erectile dysfunction in men with or without SCI. The choice of therapy is often defined more by the needs of the patient's sexual relationship than by his erectile dysfunction. The majority of men with SCI are infertile because of a combination of ejaculatory dysfunction, impaired spermatogenesis, and poor semen quality. Although many technological advances have evolved to overcome ejaculatory dysfunction, the sperm density, motility, and function remain poor. Until these parameters are improved, men with SCI will have to pursue more financially and emotionally taxing procedures. Further studies to elucidate the cellular and molecular mechanisms of diminished sperm quality are needed. Addressing the issues of erectile dysfunction and male infertility may help to preserve the relationship between the patient and his partner.