Immediate medical intervention is vital
Every 49 minutes, one American sustains and survives a spinal cord injury (SCI). Roughly 253,000 Americans are currently living with SCI, an injury which many consider devastating with limited chances and minimal hope for recovery. Accounts from recent movies such as Million Dollar Baby reaffirm this popularly held, dismal outlook for SCI patients.
During the past decade, however, a tremendous resurgence of interest in the management and treatment of SCI—sparked by Superman star Christopher Reeve—has occurred. Reeve, who was left paralyzed by a horse-jumping accident in 1995, became the face of spinal cord injury and inspired a new generation of neuroscientists and clinicians to focus on improving the quality of life for patients. Ideas from gene therapy to stem cell transplantation have been proposed as possible therapeutic adjuncts for SCI patients.
With all of the ongoing research, the first line of defense remains what happens to the patient immediately after the injury (Fig 1). The acute management of SCI patients requires a multidisciplinary, multisystem approach, and optimal treatment begins in the field with immobilization of the spine by emergency response personnel.
For many SCI patients, the orthopaedic surgeon is on the front line, overseeing spinal precautions such as external immobilization and providing the initial full examination and evaluation in the emergency department. This exam should include the diagnosis and treatment of the spinal pathology as well as any other acute or life-threatening injury.
Medical management of the SCI patient is of utmost importance (Fig 2). Traumatic injury decreases the spinal cord’s ability to autoregulate its local blood flow, which leaves the spinal cord vulnerable to systemic changes in blood flow. Data from several studies of human traumatic brain injury (TBI) have shown that hypotension (systolic < 90 mm Hg) and hypoxia (PaO2 < 60 mm Hg) are independently associated with significantly increased morbidity and mortality following TBI. Hence, a key issue in the acute medical management of the SCI patient is the maintenance of systemic blood flow and oxygenation.
Different strategies, including blood pressure support, avoidance of acute anemia, and ventilatory assistance, may be used as needed. Several SCI case series have confirmed that maintenance of systemic mean arterial pressure at 85 mm Hg to 90 mm Hg can improve neurologic outcomes, and that diagnostic and treatment interventions used to accomplish this goal are safe. Invasive hemodynamic monitoring of the patient in an intensive care unit is recommended in the acute post-injury period.
Maintaining normal blood pressure in SCI patients can be challenging. These patients frequently have multiple injuries; hypotension, hypoxemia, and anemia can be induced by varied and numerous causes. Hypotension in the multisystem trauma patient is frequently caused by hypovolemia due to hemorrhage or dehydration. Although these causes of hypotension should be pursued, decreased blood pressure in the SCI patient may occur even with normal blood volume due to decreased sympathetic outflow. This form of hypotension is known as neurogenic shock. Neurogenic shock can be distinguished from hypovolemic hypotension by the lack of appropriate cardiac response to the decreased blood pressure and the resulting relative bradycardia.
Although no particular algorithm for blood pressure maintenance has been widely accepted, researchers have generally agreed on several aspects of treatment, including invasive blood pressure monitoring with Swan-Ganz catheters or arterial lines; the use of crystalloid, colloid, or blood to optimize fluid volume; and the use of vasopressors in patients with optimal volume status but ongoing neurogenic hypotension. Based on the TBI studies, blood pressure monitoring and support is generally continued for 7 days post-injury, although studies in SCI patients have not confirmed this length of time.
In the 1990s, the management of acute spinal trauma changed with the refinement of spinal stabilization (Fig. 3 and 4). Along with changes in surgical technique, research has also focused on the search for a pharmacologic intervention to limit secondary injury.
Results from the National Acute Spinal Cord Injury Study (NASCIS) trials were initially viewed as promising, and the administration of methylprednisolone sodium succinate (MPSS) was often considered a standard of care in the acute SCI setting. More recent studies, however, have been highly critical of the interpretation of these trials, particularly the statistical analysis. Although analysis of NASCIS II revealed that the small sample of patients treated with MPSS within the first 8 hours of injury showed significantly improved motor and sensory function, clinical improvements remain modest and the efficacy of MPSS continues to be a controversial topic.
Several pharmacologic adjuncts, including opiate blockers (Naloxone), GM-1 ganglioside (Sygen), thyrotropin-releasing hormone (TRH), and erythropoietin (EPO) have been explored without any clear, consistent recommendations that have been universally adopted. Alternative experimental strategies currently being explored include stem-cell therapy and cellular-based therapies such as peripheral micrografts, olfactory ensheathing cells, and activated autologous macrophages. What role these strategies will play in the treatment of acute and chronic SCI remains to be seen.
Goals of surgical management
Goals of surgical management in the SCI patient are to stabilize the spine, to decompress the spinal canal, and to prevent further neurologic injury. Although animal SCI studies suggest that rapid decompression (less than 6 hours) may result in improved neurologic outcomes, these findings have not reliably been reproduced in humans.
The Surgical Treatment of Acute Spinal Cord Injury Study (STASCIS) hopes to address the surgical timing debate with quality, evidence-based science. Although this study has not yet been completed, the initial evidence supports that early decompression (within 24 hrs after SCI) is safe, feasible, and may be associated with improved neurological outcomes. The final results will likely enhance the argument in support of early surgical intervention, but the implementation of the STASCIS protocol will require major changes in hospital and public policy to overcome challenges related to immediate operating room access, appropriate imaging, and patient transport.
Although no reliable, effective treatment has been found for spinal cord injury, survival and outcomes have improved over the last decade. Basic science and clinical studies are focused on improving the quality of life for these patients. Improvements will certainly come through a combination of therapeutic interventions.
Regardless of these efforts, the need for the treating orthopaedic surgeon to remain integrally involved with the early management of SCI patients remains critical, to limit the damage and stabilize the patient after SCI. With continued research investigations, the dream of walking again shared by Christopher Reeve and all SCI patients comes a step closer to reality.
Ranjan Gupta, MD, is a member of the AAOS Research Development Committee and professor and chair of the department of orthopaedic surgery at the University of California, Irvine. He reports the following disclosures: Stryker and Biomet.
Nitin N. Bhatia, MD, is chief of spine surgery at the University of California, Irvine Medical Center and reports the following disclosures: Biomet, Stryker, and Alphatec Spine.