Conference Coverage

Study characterizes injury risk in cervical myelopathy patients


 

AT CSRS 2015

SAN DIEGO – Compared with age-matched controls, patients with cervical spondylotic myelopathy had a significantly increased incidence of falls, hip fractures, and other injuries, preliminary results from a study of Medicare data suggest.

“Cervical myelopathy is the most common cause of spinal cord dysfunction in patients over age 55,” Dr. Daniel J. Blizzard said at the annual meeting of the Cervical Spine Research Society. “In general, it’s cord compression secondary to their ossification of posterior latitudinal ligament, congenital stenosis, and/or degenerative changes to vertebral bodies, discs, and facet joints. These create an upper motor neuron lesion, which causes gait disturbances, imbalance, loss of manual dexterity and coordination, and sensory changes and weakness.”

Dr. Daniel J. Blizzard

Dr. Daniel J. Blizzard

Dr. Blizzard, an orthopedic surgery resident at Duke University, Durham, N.C., noted that myelopathy gait is the most common presenting symptom in cervical spondylotic myelopathy (CSM), affecting almost 30% of patients. “It’s present in three-quarters of CSM patients undergoing decompression,” he said. “Cord compression can lead to impaired proprioception, spasticity, and stiffness. We know that this gait dysfunction is multifactorial. Imbalance and unsteadiness lead to compensatory broad-based arrhythmic shuffling and clumsy-appearing gait to maintain balance.”

An estimated one-third of people over age 65 fall at least once per year and this may lead to significant morbidity, including institutionalization, loss of independence, and mortality, Dr. Blizzard continued. “We know that gait dysfunction is a significant risk factor for falls,” he said. “This can be CSM, lower extremity osteoarthritis, deconditioning, or poor vision. The primary cause of a gait disturbance may not be accurately identified, especially if a more obvious cause is already known.”

The researchers set out to determine the fall and injury risk of patients with CSM, “with the goal of guiding attention to what we thought might be a potentially underestimated disease with regard to morbidity, and to provide data to consider when determining the type and timing of CSM treatment,” Dr. Blizzard said. They used the PearlDiver database to search the Medicare sample during 2005-2012, and used ICD-9 codes to identify patients with CSM. They also identified a subpopulation of CSM patients that underwent decompression, “not for the purpose of comparing the effect of decompression, but to identify a population with more severe disease,” he explained. They included a control population with no CSM, vestibular disease, or Parkinson’s disease.

Dr. Blizzard reported preliminary results from a total of 601,390 patients with CSM, 77,346 patients with CSM plus decompression, and 49,550,651 controls. They looked at the incidence of falls, head injuries, skull fractures, subdural hematomas, and other orthopedic injuries including fractures of the hip, femur, leg, ankle, pelvis, and lower extremity sprains. The researchers found that when compared with controls, patients with CSM had a statistically significant increased incidence of all injuries, including hip fracture (risk ratio, 2.62), head injury (RR, 7.34), and fall (RR, 8.08). The incidence of hip fracture, head injury, and fall was also increased among the subset of CSM patients who had undergone decompression (RR of 2.25, 8.34, and 9.62, respectively).

Dr. Blizzard acknowledged certain limitations of the study, including its retrospective design. “Statistical and clinical significance are two very different things,” he emphasized. “When we get numbers this big, everything will become statistically significant, but whether things are clinically significant is up to interpretation. The presence of disease and complications is contingent upon proper coding and recognition by providers. We have no measures of severity, extent, or chronicity of disease.”

Despite such limitations, he concluded that the findings suggest that impact of CSM on morbidity “is probably underestimated by many. Symptoms of CSM can be insidious or masked. Patients can often attribute these to normal effects of aging, and often primary care physicians will not recognize these initial symptoms, especially if there is another confounding presenting complaint.”

Conservative interventions for CSM patients, he said, include gait training/physical therapy, assistive aids, hip pads, exercise programs with balance training, and an assessment of hazards in the home environment. From a surgical standpoint, the findings raise the possibility that surgeons may want to “be more aggressive” in their decision to operate on patients with CSM. “This dataset is in no way able to address this question, but I think it provides interesting information regarding the true morbidity of the disease,” Dr. Blizzard said. “There is clear risk and morbidity with cervical compression. Studies show improvement in patients regardless of age, severity, and chronicity.”

Dr. Blizzard reported having no financial disclosures.

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