Progress Report on NWRSCIS Research Projects
With funding from the National Institute of Disability and Rehabilitation Research (NIDRR), the Northwest Regional Spinal Cord Injury System (NWRSCIS) conducts research in different areas of SCI diagnosis and treatment. On March 13, 2003, members of the NWRSCIS Consumer Advisory Board and Scientific Advisors were invited to hear progress reports on these projects. Four projects are currently funded under the 2000-2005 NIDRR grant and one is a NIDRR-funded collaborative project.
"Hydrophilic Catheters for the Prevention of Urinary Tract Infections" is headed by Dr. Diana Cardenas , professor in the UW Department of Rehabilitation Medicine and director of the Northwest Regional Spinal Cord Injury System.
Urinary Tract Infections (UTIs) are the most frequent medical complication during initial rehabilitation and a leading cause of re-hospitalization. Cardenas' study is investigating whether a hydrophilic catheter called the LoFric reduces the frequency and/or severity of UTIs in persons with SCI or Spina Bifida who use intermittent catheterization. The LoFric catheter has an outer layer of polyvinylpyrrolidone, a hydrophilic compound which binds with water to create a liquid surface that reduces friction. "Less friction is thought to reduce trauma in the urethra," Cardenas explained, "which decreases the chance that bacteria will invade the bladder system."
Subjects are randomly assigned to either the LoFric catheter (treatment) group or the standard catheter (control) group. Over a 12-month period, subjects periodically provide urine samples for laboratory analysis and complete UTI symptom questionnaires.
Data analysis will compare both the number of UTIs in each group and the rate of infection in the first six months versus the last six months. A previous study found no difference in UTIs using this catheter (Sunderland, 1996); in another there was no difference compared to baseline but a decreased rate of UTIs over 12 months (Vapnek, 2002). "If it affects the urethra, it may take a while for the tissue to get better, and we may see improvement later on," Cardenas suggested.
Of the 35 subjects who have enrolled, 18 have completed the study-too few to draw conclusions (the goal is 75 subjects). The LoFric catheter is more expensive than a simple catheter. "If we can show that it significantly reduces the severity of infections, we can better justify insurance coverage," Cardenas said.
"The Prevalence and Implications of Sleep Apnea in Acute, Traumatic Tetraplegia" is led by Dr. Stephen Burns , assistant professor in Rehabilitation Medicine. Sleep apnea syndrome is a disorder characterized by frequent, brief pauses in breathing during sleep that result in reduced oxygen flow to the brain. It occurs in 3-4% of the general population, mostly middle-age males; is a common cause of daytime sleepiness and cognitive problems; and is associated with increased rates of motor vehicle accidents, hypertension, depression and mortality.
Sleep apnea is ten times more common in the SCI population and is thought to be even more prevalent in newly injured patients. Burns believes that sleep apnea in acute SCI patients may impede the rehabilitation process and inhibit the attainment of optimal function, emotional health and quality of life.
Subjects are drawn from the population of all patients with acute tetraplegia admitted to Harborview Medical Center during the grant period. Eligible subjects found to have sleep apnea are offered treatment with a CPAP device (continuous positive airway pressure via a nasal/face mask). Information about the subject's symptoms, rehabilitation activities, and treatment effectiveness is collected during the inpatient stay.
So far, nine subjects have been enrolled (the goal is 20) and six of these have been diagnosed with sleep apnea. Treatment with CPAP-effective in the general population-has not been well-tolerated in this group. "They don't like having something strapped to their faces that they can't reposition or adjust," said Burns, who hopes studies such as this will help identify treatments that address the specific needs of this population.
"We might be able to have people do better in rehabilitation, attain their goals faster and be a little more independent when they leave, if they are learning rehabilitation skills while well-rested." Burns and his colleagues are also surveying physicians and patients to learn more about the extent and nature of sleep apnea in the chronic SCI population.
"Neurologic Recovery After SCI," directed by Dr. Sohail Mirza , associate professor of Orthopedic Surgery, is examining acute SCI cases that occurred in the last two decades to determine whether earlier spine surgery results in better neurological recovery than later surgery, how much improvement occurs with earlier intervention, and what the complication rates are. This study hopes to shed light on the controversy over timing of surgery: is it better to perform surgery very soon after injury, before further damage occurs, or later, after the patient has stabilized and risks from surgery have declined?
One of the primary goals of surgery after SCI is to reduce or prevent further damage caused by inflammation and other physiologic changes the body sets in motion in response to injury. "Most (of the destructive) changes happen in the first six hours after injury," Mirza said. "The majority of studies, however, have compared surgery within three days (of injury) to surgery after seven days. But three days might be too long a window." This may explain why previous studies didn't show much difference in results between "early" and "late" surgery.
Five hundred records from a database of all acute SCI admissions to the UW since 1985 are being reviewed. These cases are divided into early (within three hours) versus later (after day one) surgery. For each group, Mirza's research team is examining rates of recovery and complications. As of March 2003, 100 charts had been reviewed. "Our impression so far," Mirza said, "is that early decompression does make a difference and produces a better result." Studies such as this can have far-reaching implications for treatment of spine trauma.
Jason Doctor, PhD , Assistant Professor of Medical Education and Biomedical Informatics, Rehabilitation Medicine and Health Services, is the principal investigator of the study "Measuring the Value of Spinal Cord Injury Health Outcomes Under Risk." This study examines the way patients with SCI make decisions about high risk medical procedures that may or may not result in significant improvements in health and quality of life. In interviews, study participants are asked to make risky choices that quantify their preferences and assess their attitude toward taking medical risk under a variety of hypothetical conditions.
Findings suggest that persons with SCI demonstrate the common human tendency to over-weight the probability of a good medical outcome when the chance of such an outcome is small, and under-weight the probability of a good medical outcome when the chance of such an outcome is large. When preferences for health are assessed in the context of risk, the effect of this over- and under-weighting of probability is to misrepresent the value persons place on their health. Results of this research may help guide both researchers and patients as to the value of various risky treatments that target regeneration of spinal nerve cells.
"Collaborative Upper Limb Pain (CULP-SCI)," a three-site collaborative study centered at the University of Pittsburgh, looks at the manual wheelchair propulsion and transfer techniques used by people with SCI that over time may be contributing to the high incidence of disabling upper limb pain in this population. The Seattle arm of the study is directed by Dr. Michael Chang , associate professor of Rehabilitation Medicine. Subjects receive an initial evaluation consisting of biomechanical studies in the UW's state-of-the-art Human Motion Analysis Laboratory that measure kinematics (joint motion) and kinetics (force through the joints) during wheelchair propulsion and transfer; shoulder MRI; nerve conduction study of the ulnar and median nerves; and physical exam. For the next five years, subjects are interviewed regularly about their upper limb pain and disability. "Upper limb pain is a very common problem that contributes significant disability and limitations on employment and activities of daily living," Chang said. This study will eventually enroll 225 subjects from the three centers (University of Pittsburgh, Kessler and UW).