Modulation of the Endocannabinoid System Following Central Nervous System Injury.

Central nervous system (CNS) injury, such as stroke or trauma, is known to increase susceptibility to various infections that adversely affect patient outcomes (CNS injury-induced immunodepression-CIDS). The endocannabinoid system (ECS) has been shown to have immunoregulatory properties. Therefore, the ECS might represent a druggable target to overcome CIDS. Evidence suggests that cannabinoid type 2 receptor (CB2R) activation can be protective during the early pro-inflammatory phase after CNS injury, as it limits neuro-inflammation and, therefore, attenuates CIDS severity. In the later phase post CNS injury, CB2R inhibition is suggested as a promising pharmacologic strategy to restore immune function in order to prevent infection.

Neurophysiological monitoring during neurosurgery: anesthetic considerations based on outcome evidence.

PURPOSE OF REVIEW: This article reviews the recent outcome studies that investigated intraoperative neurophysiological monitoring (IONM) during spine, neurovascular and brain tumor surgery. RECENT FINDINGS: Several recent studies have focused on identifying which types of neurosurgical procedures might benefit most from IONM use. Despite conflicting literature regarding its efficacy in improving neurological outcomes, many experts have advocated for the use of IONM in neurosurgery. Several themes have emerged from the recent literature: the entire perioperative team must always work together to ensure adequate communication and intervention; systems and checklists, in which each member of the perioperative team has a clearly defined role, can be useful in the event of a sudden intraoperative changes in electrophysiological signals; regardless of the IONM modality used, any sudden change in electrophysiological signal should prompt an immediate and appropriate intervention; a multimodal IONM approach is often, but not always, advantageous over a single IONM approach. SUMMARY: For neurosurgical procedures that can be complicated by neural injury, the use of IONM should be considered according to specific patient and surgical factors. Future studies should focus on improving IONM technology and optimizing sensitivity and specificity for detecting any impending neural damage.

In Vogue: Ketamine for Neuroprotection in Acute Neurologic Injury.

Neurologic deterioration following acute injury to the central nervous system may be amenable to pharmacologic intervention, although, to date, no such therapy exists. Ketamine is an anesthetic and analgesic emerging as a novel therapy for a number of clinical entities in recent years, including refractory pain, depression, and drug-induced hyperalgesia due to newly discovered mechanisms of action and new application of its known pharmacodynamics. In this focused review, the evidence for ketamine as a neuroprotective agent in stroke, neurotrauma, subarachnoid hemorrhage, and status epilepticus is highlighted, with a focus on its applications for excitotoxicity, neuroinflammation, and neuronal hyperexcitability. Preclinical modeling and clinical applications are discussed.

A New Combined Technique Reducing the Risk of Paraplegia during Thoracoabdominal Aorta Replacement.

Acute spinal cord ischemia during thoracoabdominal aorta replacement is a dreadful complication. Existing tools (motor evoked potential [MEP] and somatosensory evoked potential [SSEP]) do not allow differentiating between central and peripheral paraplegia. Therefore, the surgeon often performs unnecessary reimplantation of intercostal arteries: this is time consuming, and significantly increases bleeding complications. We present a simple technique combining MEP and peripheral compound muscle action potential induced by posterior tibialis nerve stimulation, enabling the surgeon to quickly discriminate between central and peripheral neurologic injury. The surgeon has one more tool to drive in real time the optimal surgical strategy. This strategy guides the decision as to which side branches ought to be reimplanted, thus minimizing the risk of paraplegia.

Survival, Neurologic Injury, and Kidney Function after Surgery for Acute Type A Aortic Dissection.

BACKGROUND: To analyze survival, neurologic injury, and kidney function after acute type A aortic dissection. METHODS: A total of 445 patients undergoing surgery for acute type A aortic dissection were analyzed. Evaluation according to risk factors for mortality, neurologic injury, and kidney function was performed. RESULTS: Overall 1-, 5-, and 10-year survival rates were 82.8 ± 1.8%, 73.6 ± 2.4%, and 59.3 ± 3.9, respectively. Independent preoperative risk factors for mortality were preexisting renal impairment (p = 0.001), reduced left ventricular ejection fraction (p < 0.001), and age (p < 0.001). Perioperative risk factors were prolonged cross-clamp (p < 0.001) and cerebral perfusion time (p = 0.001). Risk factors for renal failure were preexisting renal impairment (p < 0.001), prolonged cross-clamp time (p < 0.001), cerebral perfusion time (p < 0.001), and age (p = 0.022). Risk factors for neurologic injury were cross-clamp time (p = 0.038), cerebral perfusion time (p = 0.007), and age (p = 0.045). CONCLUSION: In addition to classic risk factors, survival after type A aortic dissection is affected by preexisting renal impairment. Preexisting renal impairment is predictive of postoperative renal failure. Therefore treatment and prevention strategies for renal failure during the acute and long-term course after acute type A aortic dissection are warranted.

Introduction of a simple guideline to improve neurological assessment in paediatric patients presenting with upper limb fractures.

BACKGROUND: Neurological examination in children presenting with upper limb fractures is often poorly performed in the Emergency Department (ED). We aimed to assess the improvement in documented neurological examination for children presenting with upper limb fractures following introduction of a simple guideline. METHODS: We developed and introduced a simple guideline for upper limb neurological assessment in children ('rock, paper, scissors, OK'). We compared documentation of neurological examination and nerve injury detection at our hospital before and after introduction of this guideline, as well as for children admitted from external hospitals (where the guideline had not been introduced). RESULTS: In the period following guideline introduction, 97 children with upper limb fractures were admitted (46% presenting directly to our ED and 54% admitted from external hospitals). This cohort was similar in number and distribution to the cohort reviewed prior to the guideline. Documentation of neurological examination in our ED increased from 92% to 98% after guideline introduction. Documented information on nerves examined also increased from 2% to 68% (p<0.01). Prior to the guideline, there were six nerve injuries, all of which were missed in our ED. After guideline introduction, there were four nerve injuries, all of which were detected in our ED. Documentation and nerve injury detection at external hospitals over the same time period showed no improvement. CONCLUSIONS: A simple guideline to assist neurological examination in children with upper limb fractures can significantly improve the quality of documented neurological assessment and nerve injury detection.

Management of pediatric craniocervical arterial dissections.

PURPOSE: Craniocervical arterial dissections (CCADs) represent a preventable cause of acute ischemic stroke (AIS). Our objective was to describe clinical presentation, imaging features, treatment strategies, and report clinical and imaging outcomes of CCADs at a large pediatric tertiary referral center. METHODS: Electronic medical records were queried using variations of the word dissection for patients under 25 years of age with neuroimaging over a 13-year period. Medical and imaging records were reviewed to identify carotid, vertebral, or intracranial dissections. Demographics, presenting symptoms, presence of AIS, mechanism of injury, dissection location, dissection treatment, and complications stemming from treatment were collected. Clinical outcome was classified according to modified Rankin Scale (mRS) score. Imaging follow-up was obtained until the dissection healed or stabilized. RESULTS: A total 6,289 patients met initial search criteria. Of the 42 (0.7%) patients with CCADs, 23 (54.8%) had internal carotid artery (ICA) dissections, and 17 (40.5%) had vertebrobasilar (VB) dissections. More females had ICA dissections (p = 0.002), and more males had VB dissections (p = 0.01). CCADs associated with traumatic presentation occurred in 34 patients (81.0%), while 8 (19.0%) were spontaneous. Good outcomes (mRS 0-3) were noted for 36 patients, and 5 had poor outcomes (mRS 4-6). In the 17 patients with vessel occlusion, 50.0% had partial or complete recanalization at a mean follow-up of 23.9 months. CONCLUSIONS: CCAD is commonly related to trauma and presents with AIS. The majority of patients experience good clinical outcome. Recanalization of initial vessel occlusion occurs in half of cases at 2 years.

An evidence-based approach towards the cranio-cervical junction injury classifications.

PURPOSE: The cranio-cervical junction (CCJ) is an anatomically, functionally and biomechanically complex region. It is commonly involved in trauma of varying severity that can be managed with a multitude of treatment options and carry diverse prognosis. Our objective is to evaluate the quality of currently used CCJ injury classifications in an evidence-based approach. METHODS: We performed two consecutive literature reviews. In the first, we tried to find which classifications are currently used in CCJ injuries. In the second, we scrutinized the gathered classifications in terms of validity, reliability, severity grading, treatment guidance and prognosis assessment. RESULTS: Twenty classifications are currently used to describe the CCJ injuries and 72 individual injury patterns have been recognized. Almost a third of them can grade severity, guide treatment and assess prognosis. Only two classifications have been tested for validity and reliability. CONCLUSIONS: CCJ injuries are poorly described by the current classifications according to evidence-based criteria. There is an obvious need for a simple and reliable classification tool to guide patient management in the evidence-based medicine era.

Neuroimaging findings of retroclival hemorrhage in children: a diagnostic conundrum.

BACKGROUND: Retroclival hemorrhage in children may occur in three compartments, namely epidural, subdural, and subarachnoid, frequently secondary to trauma. Retroclival epidural hematoma may be associated with ligamentous injury, which may further result in instability at the craniocervical junction. Retroclival subdural hematoma may indicate a sentinel event for traumatic injury elsewhere within the brain or posterior fossa. Retroclival subarachnoid hemorrhage may have severe clinical consequences related to vasospasm. OBJECTIVE: Neuroimaging is essential in the recognition, localization, and characterization of retroclival hemorrhage into various compartments and for evaluating potential severe clinical consequences such as craniocervical junction instability, underlying traumatic brain injury, and ischemia secondary to vasospasm. The goal of this paper is to discuss the anatomy and biomechanics of the craniocervical junction as well as the neuroimaging findings associated with various compartments of retroclival hemorrhage in children.

Optogenetic-guided cortical plasticity after nerve injury.

Peripheral nerve injury causes sensory dysfunctions that are thought to be attributable to changes in neuronal activity occurring in somatosensory cortices both contralateral and ipsilateral to the injury. Recent studies suggest that distorted functional response observed in deprived primary somatosensory cortex (S1) may be the result of an increase in inhibitory interneuron activity and is mediated by the transcallosal pathway. The goal of this study was to develop a strategy to manipulate and control the transcallosal activity to facilitate appropriate plasticity by guiding the cortical reorganization in a rat model of sensory deprivation. Since transcallosal fibers originate mainly from excitatory pyramidal neurons somata situated in laminae III and V, the excitatory neurons in rat S1 were engineered to express halorhodopsin, a light-sensitive chloride pump that triggers neuronal hyperpolarization. Results from electrophysiology, optical imaging, and functional MRI measurements are concordant with that within the deprived S1, activity in response to intact forepaw electrical stimulation was significantly increased by concurrent illumination of halorhodopsin over the healthy S1. Optogenetic manipulations effectively decreased the adverse inhibition of deprived cortex and revealed the major contribution of the transcallosal projections, showing interhemispheric neuroplasticity and thus, setting a foundation to develop improved rehabilitation strategies to restore cortical functions.

Individualized endovascular treatment of high-grade traumatic vertebral artery injury.

BACKGROUND: Traumatic vertebral artery injury (TVAI) is associated with craniocervical trauma that can lead to potentially fatal posterior circulation stroke. It presents a clinical challenge since it is hard to detect and there are no widely accepted guidelines on diagnosis and management. High-grade TVAI is more difficult to treat and no consensus has been reached yet. METHODS: We performed a single-center, long-term, therapeutic study involving 272 patients with craniocervical injury, eleven of which were diagnosed with high-grade TVAI. Individualized endovascular treatments were performed on these patients based upon the hemodynamic and morphological characteristics of the injured vertebral artery. Postoperative angiography was conducted at 2 weeks, 3 months and 6 months, and then annually after intervention. RESULTS: Ten vertebral pseudoaneurysms and one arteriovenous fistula (AVF) were confirmed by postoperative angiography. All the participants' neurological deficit symptoms disappeared or were significantly alleviated gradually, and no new symptoms were found after endovascular treatment. Follow-up angiography of the patients with pseudoaneurysms showed a normally shaped vertebral artery with no stenosis or aneurysms; the angiographic result of the patient with the AVF presented successful embolization in the proximal vertebral artery fistula with no progression or new stenosis. Their modified Rankin Scale (mRS) scores were also satisfactory. CONCLUSIONS: Application of individualized endovascular therapy in high-grade TVAI is safe, technically feasible and clinically effective, but there is no comparison between endovascular management and other management approaches because randomized trials cannot be carried out currently.

Characteristics of spinal injuries secondary to nonaccidental trauma.

BACKGROUND: Nonaccidental trauma (NAT) is considered an uncommon cause of spine trauma in the pediatric population. Little has been published on such injuries and no large series is available in the literature. The purpose of this study is to describe the incidence and characteristics of spine trauma secondary to NAT. METHODS: An IRB-approved retrospective review of all patients presenting to a single level 1 pediatric trauma center with a spinal injury between 2003 and 2011 was performed. Patients were identified using our institution's trauma registry. Medical records were reviewed to identify all spine injuries that occurred as a result of NAT. These cases were reviewed for details regarding injury mechanism, type and location of injury, associated injuries, and the treatment. Our institution's NAT database was also queried to identify the total number of patients formally determined to have sustained any injury as a result of NAT during the same period. RESULTS: NAT was the cause of 11/342 (3.2%) spine injuries diagnosed during the study period. A total of 726 cases of NAT were identified, with spine injury present in 1.5%. All patients with spine trauma secondary to NAT were under the age of 2 years with an average age of 7 months. Among patients below 2 years with spinal trauma, NAT was tied as the most common mechanism, resulting in 38% of injuries. Eight of the 11 patients' spine injuries were cervical and 7 of these injuries were in the atlanto-occipital and atlantoaxial regions. Multilevel spine trauma was present in 64% of patients. Associated head and thoracic trauma was present in 73% and 36% of patients, respectively. Neurological injury was found in 54% of patients. The majority of injuries were treated nonoperatively and 1 patient required surgical management. CONCLUSIONS: NAT represents a very common yet often overlooked cause of spinal trauma in children under the age of 2 years. Because of its frequency in this age group, clinicians should consider including an assessment of the spine in all young NAT patients. Patients with spinal trauma sustained as a result of NAT must undergo a thorough evaluation for associated injuries remote to the spine, neurological deficit, and multilevel spine injury. SUMMARY: NAT is a common mechanism of spinal injury in patients below 2 years of age.

[Feasibility and limits of clinical neurophysiology with regard to the objective evaluation of neurological consequences following accidents]. / Möglichkeiten und Grenzen der klinischen Neurophysiologie zur Objektivierung neurologischer Unfallfolgen.

It is not unusual for a neurological expert to have problems defining the precise anatomical location and the required objective proof of damage, especially if the medical history and the neurological report released by the clinic prove inadequate in terms of providing a reliable assessment. This may well result from somatoform disorders, dissociation, aggravation and simulation, as well as dissimulation and complex organic diagnostic findings. A range of standardised neurophysiologic procedures is available for the objective measuring of motor, vegetative and sensory systems; a brief summary of the most frequent occurrences is given here, along with their significance for appraising damage resulting from an accident. Target groups primarily include surgeons, orthopaedists, lawyers and insurance specialists. Structural improvements and measures to integrate immigrant doctors is essential.

Severe spinal cord injury in craniocervical dislocation. Case-based update.

BACKGROUND: Craniocervical distraction injuries, including atlanto-axial dislocation (AAD) and atlanto-ocipital dislocation (AOD), are often associated with severe spinal cord involvement with high morbidity and mortality rates. Many patients with these injuries die at the accident scene, but advances in emergency resuscitation and transport permit that many patients arrive alive to hospitals. DISCUSSION: Children with craniocervical distraction injuries usually present with a severe cranioencephalic traumatism that is the most relevant lesion at admission. After resuscitation and hemodynamic stabilization, the spinal cord damage appears as the main lesion. Apnea and quadriparesis, or quadriplegia, are usually present at the onset. Early diagnosis and management perhaps decrease life-threatening manifestations of the spinal lesion. But even so, the primary spinal cord insult is often irreversible and precludes obtaining a satisfactory functional outcome. PATIENTS AND METHODS: We report the findings of four children with craniocervical distraction injuries (AOD and AAD) who presented with severe spinal cord damage. All patients were admitted with respiratory distress or apnea together with significant brain injuries. The medical records pertaining to these patients are summarized in regard to clinical features, management, and outcome. CONCLUSIONS: In spite of timely and aggressive management, craniocervical injuries with spinal cord involvement continue to have a dismal prognosis. Outcome is closely related to the severity of the initial brain and spinal cord damage and is nearly always fatal in cases of complete spinal cord transection. Priority should be given to life-threatening complications. Ethic issues on indications for surgery deserve a detailed discussion with the children's parents.

[The srategy of programed multistage surgical treatment ("damage control surgery") of neurotrauma].

A retrospective analysis of diagnostics and surgical treatment was made in 440 patients with polytrauma, who were on the treatment in hospitals in Saint-Petersburg, Syktyvkar and Omsk during 2009-2012. The neurotrauma was the dominating damage. The patients were divided into two groups: the main and the control group, using the equal quantitative ratio according to the sex, age, circumstances of trauma and type of damages. The strategy of programmed multistage surgical treatment ("damage control surgery") was used in the main group (220 patients, average age 31.7 +/- 5.2 years). The traditional strategy of treatment was applied in the control group (220 patients, average age 30.7 +/- 5.4 years). The damage control surgery allows the reduction of lethality in neurotrauma by 15.0% and improvement of social adaptation of patients by 12.7%.

Preliminary study of the types of traumatic peripheral nerve injuries by ultrasound.

OBJECTIVES: To investigate the types of traumatic peripheral nerve injuries by ultrasound (US). To demonstrate the efficacy of US in case of peripheral nerve injuries and, in particular, its importance of demonstrating and monitoring the appearances of the nerve itself. METHODS: Two hundred and two patients, of which 117 subsequently underwent operative treatment, were prospectively examined by US in such a way that the transducer was moved to the nerve damaged region from the normal nerve located near a known anatomical landmark. The ultrasound features of the traumatic peripheral nerve injuries were classified according to abnormal fascicle, perineurium, epineurium, and peripheral tissues of peripheral nerve. RESULTS: The ultrasound features of the traumatic peripheral nerve injuries were classified into 7 types. In the 117 cases that underwent operative treatment, the accuracy of classification by using US was 93.2%. CONCLUSIONS: Ultrasound seems to be a valuable investigation for evaluating the type of traumatic peripheral nerve injury.

Pediatric craniocervical junction injuries.

OBJECTIVE: The purpose of this article is to review pediatric craniocervical junction injuries in the context of embryology, developmental anatomy, and biomechanics. CONCLUSION: The craniocervical junction is functionally and developmentally distinct from the rest of the spine, and mechanistic models often fail to explain these injuries. Various developmental features and complex anatomy likely contribute to injury in this region in children. Some of the injury patterns at the craniocervical junction in children are similar to adults, but many are unique.

The development and evaluation of the subaxial injury classification scoring system for cervical spine trauma.

BACKGROUND: Fractures and dislocations of the subaxial cervical spine may give rise to devastating consequences. Previous algorithms for describing cervical trauma largely depend on retrospective reconstructions of injury mechanism and utilize nonspecific terminology which thus diminish their clinical relevance add to the difficulty of educating doctors and performing prospective research. QUESTIONS/PURPOSES: We characterized the potential benefits of the Subaxial Injury Classification (SLIC) scale which considers three major variables that influence spinal stability: morphology, integrity of the discoligamentous complex, and neurologic status. Each category was assigned a certain number of points based on the severity of the injury which are added together to generate a total score; this value provides prognostic information and may also be useful for directing subsequent management (ie, nonoperative treatment versus operative intervention). METHODS: We examined the individual components that comprise the SLIC paradigm and reviewed the manner in which cervical injuries are scored and stratified. We also critically assessed the preliminary data comparing the SLIC scheme to preexisting classification systems. RESULTS: The results of a preliminary analysis demonstrate that the intraclass coefficients (ICC) for the three primary components range between 0.49 and 0.90, suggesting that the overall reliability of the SLIC system appears to be at least as good as that of other conventional schemes for classifying subaxial cervical spine trauma (ICC between 0.41 and 0.53). CONCLUSIONS: This scheme will hopefully facilitate the development of evidence-based guidelines that may influence other aspects of the therapeutic decision-making process (eg, which operative approach is most appropriate for a particular injury). We anticipate its accuracy and reproducibility will increase over time as surgeons become more familiar with the protocol.

Nerve monitoring during proximal humeral fracture fixation: what have we learned?

BACKGROUND: The incidence of neurologic injury after proximal humerus fractures is variable, ranging from 6.2% to as much as 67%. However, it is unclear what factors might contribute to these injuries or whether they can be prevented by intraoperative nerve monitoring. QUESTIONS/PURPOSES: Therefore, using intraoperative nerve monitoring, we assessed the incidence, pattern of nerve involvement, and predisposing factors for nerve injury before and during shoulder fracture fixation. PATIENTS AND METHODS: We used continuous intraoperative monitoring of the brachial plexus in 37 patients undergoing open operative treatment of proximal humerus fractures. Impending intraoperative compromise of nerve function was signaled by sustained neurotonic EMG activity or greater than 50% amplitude attenuation of transcranial electrical motor evoked potentials (MEPs) (or both). When a nerve alert occurred, current surgical activity and arm and retractor position were recorded and adjustments were made to relieve tension. RESULTS: The intraoperative affected nerves included axillary (46%), combined (mixed plexopathy) (23%), radial (23%), musculocutaneous (4%), and ulnar (4%). Postoperatively, three patients had transient nerve palsies, which fully resolved within 3 weeks of surgery. Low body mass index (BMI) (22.7 ± 2.8), history of cervical spine disease, diabetes mellitus, and delay in surgical treatment (14 ± 2.9 days from time of injury) were associated with an increased incidence of nerve dysfunction. CONCLUSIONS: Our observations suggest transcranial electrical MEPs are sensitive indicators of impending iatrogenic injury to the brachial plexus or peripheral nerves (or both) during open operative treatment of proximal humerus fractures. The use of intraoperative nerve monitoring during these procedures may be considered for the prevention of nerve injury, particularly in patients with underlying cervical spine disease, low BMI, diabetes mellitus, and/or delay in surgical treatment greater than approximately 14 days. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Thoracolumbar Spine Trauma.

Thoracolumbar spine trauma can result in potentially life-threatening consequences and requires careful management to ensure good outcomes. The purpose of this chapter is to discuss the anatomy, diagnostic tools, non-operative, and operative treatments important when addressing thoracolumbar trauma.