Physiological instability of the spinal cord following injury

The neuroanatomical-functional paradox in spinal cord injury

Although lesion size is widely considered to be the most reliable predictor of outcome after CNS injury, lesions of comparable size can produce vastly different magnitudes of functional impairment and subsequent recovery. This neuroanatomical-functional paradox is likely to contribute to the many failed attempts to independently replicate findings from animal models of neurotrauma. In humans, the analogous clinical-radiological paradox could explain why individuals with similar injuries can respond differently to rehabilitation. We describe the neuroanatomical-functional paradox in the context of traumatic spinal cord injury (SCI) and discuss the underlying mechanisms of the paradox, including the concepts of lesion-affected and recovery-related networks. We also consider the various secondary complications that further limit the accuracy of outcome prediction in SCI and provide suggestions for how to increase the predictive, translational value of preclinical SCI models.

Traumatic spinal injury and spinal cord injury: point for active physiological conservative management as compared to surgical management

The controversy about surgical vs conservative treatment of the injured spine with cord damage is centuries old. Until the end of the Second World War the majority of patients died or lived a short miserable life. Subsequently, Guttmann, an experienced neurosurgeon, realised surgery was not beneficial and sometimes detrimental to the person with spinal cord injury. Guttman, Frankel and others demonstrated with expert conservative management of the spine and the multi-system consequences of cord damage most patients made some neurological recovery and most with incomplete cord injury recovered ambulation regardless of X-ray findings. Attention to the non-medical effects of paralysis and post discharge supervision enabled persons with SCIs to enjoy complication free, dignified, productive and even competitive lives in sport and employment. The introduction of CT, MRI and safe anaesthesia led to the beliefs that surgical realignment, stabilisation and/or decompression improved neurologic outcome, facilitated early mobilisation and completion of rehabilitation, shortened hospitalisation, facilitated management and reduced cost. However, there is no supporting evidence for these claims. This manuscript describes the rationale and outcomes of conservative management and the weakness of the arguments for surgical management.

Evidence-based respiratory management strategies required to prevent complications and improve outcome in acute spinal cord injury patients

Spinal injuries without neurological damage have little effects on respiratory function unless associated with injury to the chest wall. Early verticalisation or mobilisation of these patients is safe and likely to improve vital capacity. Spinal injury with cord damage has a profound effect on the mechanics of respiration and on respiratory function particularly in cervical cord injuries. Around 40% of spinal cord injuries occur in the cervical spine, a trend that is steadily increasing, with respiratory causes being responsible for death in over 20% of individuals. Loss of lung volumes and relative hypoxemia contribute to global hypoxaemia, exacerbating cord ischaemia in the acute period. Respiratory compromise results in the loss of muscle strength generation capacity and reduced lung volumes and in particular vital capacity, of up to 70%, ineffective cough and secretion clearance abilities; reductions in both lung and chest wall compliance and an additional oxygen cost of breathing due to changes in respiratory mechanics, with obstructive sleep apnoea evident in over 50% of acute tetraplegics. While some countries have specialist spinal centres to manage such catastrophic trauma with a demonstrable improvement in health outcomes attributed to their contribution, many individuals are initially admitted to local hospitals where healthcare professionals are less likely to fully appreciate the significant and continued vulnerabilities of such individuals. This article aims to provide a basic understanding of the causes and identification of the main principles of the respiratory management strategies required to maintain pulmonary health for cervical spinal cord injury patients during the initial and early post trauma phase.

Active physiological conservative management in traumatic spinal cord injuries – an evidence-based approach

The management of the traumatic spinal cord injury remains controversial. Guttmann demonstrated that with simultaneous attention to all medical and non-medical effects of the spinal cord injury, a significant number of patients recovered motor and sensory functions to ambulate and the majority were pain-free following conservative management. Active physiological conservative management of the spinal injury requires simultaneous scrupulous care of the injured spine together with; the multisystem neurogenic effects of the spinal cord injury on the respiratory, cardiovascular, urinary, gastrointestinal, dermatological, sexual and reproductive functions; the management of the associated psychological effects of paralysis from the early hours or days of injury as well as; the physical rehabilitation and modification of the environment. To date, there is no evidence to suggest that the surgical decompression and/or stabilisation of the neurologically impaired spinal cord injury patient is advantageous. This article considers the debates and evidence of surgical management including the effects of timing of the surgical decompression. Also addressed are the factors influencing decisions on management, prognostic indicators of recovery and natural history of complete and incomplete cord injuries. Traumatic biomechanical instability of the spine, physiological instability of the spinal cord, traumatic spinal canal encroachment and traumatic cord compression are also discussed. Early mobilisation, indications for surgery at the RJAH and economic considerations of spinal cord injuries are presented. The ultimate goals of the active physiological conservative management are to ensure maximum neurological recovery and independence, a pain-free and flexible spine, safe and convenient functioning of the various systems of the body with minimal inconvenience to patients and the prevention of complications.

Traumatic spinal cord injury: the relationship between pathology and clinical implications

The pathological effects of traumatic spinal cord injuries (SCI) encompass the pathology affecting the spinal cord. As a result of the interruption of spinal cord conduction, one or more pathological and patho-physiological processes affect almost every system of the human body. Knowledge of the pathological processes that affect the spinal cord and the various systems of the body is essential for the safe and good management of these patients. The small incidence (10-15 per million per year) of these highly complex conditions makes it difficult for skills and experience to develop in District General Hospitals in the management of these patients. The associated sensory impairment or loss present diagnostic challenges to the clinician in almost every aspect of paralysis and throughout the patient’s life.

In the acute stage simultaneous good management of the multi-system impairments and malfunctions giving equal attention to all systems including that of the traumatized spine is the key to good quality outcome. Concentrating resources at any one time on any one particular aspect of paralysis is unlikely to yield a similarly good outcome. The neurological outcome does not depend only on the quality of the management of the SCI. The traumatized physiologically unstable spinal cord is vulnerable and unable to protect itself from non-mechanical complications outside the spinal canal, many of which can easily develop in patients with SCI adding to the threats from the biomechanical instability.

To date there are many controversies in the management of many aspects of paralysis at all stages following injury. One of the main current controversies is in the management of the SCI itself. There are many reasons that seem to perpetuate this controversy. Some of the reasons may be related to different interpretations of the pathological processes that affect the vertebral axis and the spinal cord as well as their effects on neurological outcome. The natural history of neurological recovery following SCI is not always duly acknowledged.

Variability in the treatment of acute spinal cord injury in the United Kingdom: results of a national survey

The aim of this study was to examine how traumatic spinal cord injury is managed in the United Kingdom via a questionnaire survey of all neurosurgical units. We contacted consultant neurosurgeons and neuroanesthetists in all neurosurgical centers that manage patients with acute spinal cord injury. Two clinical scenarios-of complete and incomplete cervical spinal cord injuries-were given to determine local treatment policies. There were 175 responders from the 33 centers (36% response rate). We ascertained neurosurgical views on urgency of transfer, timing of surgery, nature and aim of surgery, as well as neuroanesthetic views on type of anesthetic, essential intraoperative monitoring, drug treatment, and intensive care management. Approximately 70% of neurosurgeons will admit patients with incomplete spinal cord injury immediately, but only 40% will admit patients with complete spinal cord injury immediately. There is no consensus on the timing or even the role of surgery for incomplete or complete injuries. Most (96%) neuroanesthetists avoid anesthetics known to elevate intracranial pressure. What was deemed essential intraoperative monitoring, however, varied widely. Many (22%) neuroanesthetists do not routinely measure arterial blood pressure invasively, central venous pressure (85%), or cardiac output (94%) during surgery. There is no consensus among neuroanesthetists on the optimal levels of arterial blood pressure, or oxygen and carbon dioxide partial arterial pressure. We report wide variability among U.K. neurosurgeons and neuroanesthetists in their treatment of acute traumatic spinal cord injury. Our findings reflect the lack of Class 1 evidence that early surgical decompression and intensive medical management of patients with spinal cord injury improves neurological outcome.

Possible implication of leukocytes in secondary pathological changes after spinal cord injury

We reviewed 95 consecutive patients with cervical spinal cord injury admitted within 2 days of injury and treated nonoperatively, to elucidate the relationship between neurological deterioration and the white blood cell count in the first 4 days after injury. The count for 14 patients who had neurological deterioration was 13.2 +/- 3.2 x 10(9)/l, and that for 81 patients who had no deterioration was 11.0 +/- 3.1 x 10(9)/l. None of 19 patients whose highest white blood cell count was less than 9 x 10(9)l deteriorated, while 14 of 76 patients whose count was 9 x 10(9)/l or more deteriorated. These results suggest that the white blood cell is important in the secondary pathological changes after mechanical injury to the spinal cord.

Neurologic outcome in conservatively treated patients with incomplete closed traumatic cervical spinal cord injuries

STUDY DESIGN

The neurologic outcomes in patients with conservatively managed incomplete closed traumatic cervical spinal cord injuries was evaluated using the motor scoring system and the Frankel classification.

OBJECTIVES

To show that the motor scoring of recovery system combined with functional Frankel grading will make the documentation of final neurologic outcome more accurate for future comparisons of various methods of treatment.

SUMMARY OF BACKGROUND DATA

The influence of surgical and pharmacologic methods of treatment on recovery remains debatable.

METHODS

Sixty-three consecutive patients with incomplete cervical injuries who were admitted to the hospital within 2 days after injury were included. All patients were treated conservatively with 6 weeks of bedrest and 6 weeks of mobilization with neck support.

RESULTS

Five patients had neurologic deterioration, and all but one patient recovered without surgery. The evaluation of 44 patients who were observed for more than 12 months showed that the preservation of sharp sensation below the level of injury was an indicator of a good prognosis in patients whose injuries were classified as Frankel B, and the degree of recovery of these patients according to the motor score system was comparable with that of patients who were classified as Frankel C. All patients classified as Frankel C who did not deteriorate recovered in Frankel grade. All but one of the patients in the Frankel D group recovered full motor power. The degrees of motor deficit and recovery did not correlate with the mechanism or the degree of the injury of the spinal axis.

CONCLUSION

Conservative treatment remains a good option for patients with incomplete cervical cord injuries. It is hoped the current study will be a good basis for comparison of the neurologic outcomes of different treatment modalities.