Study design: A large prospective longitudinal cohort study (n = 1204) to identify prevalence of new or recurrent injury and risk factors in a rehabilitated chronic disabling spinal disorder patient group with matched control subjects.
Objectives: To evaluate prevalence and risk factors for new or recurrent injury on a chronic disabling spinal disorder population.
Summary of background data: The rate of symptom recurrence after acute low back pain, like the rate of initial back pain episodes, is extremely high (40-70%). However, although the incidence of recurrent back pain after chronic disabling spinal disorder represents a small subcomponent of these cases, there is a large socioeconomic impact. An individual attempting to return to work after a chronic disabling spinal disorder episode usually bears a stigma of "high risk" for recurrent injury and related work disability that may result in barriers to reemployment or work retention. Before the present research, no large scale studies had been conducted to evaluate whether recurrent spine injuries or new injuries to other musculoskeletal areas could be prevented by medical treatment. In addition, no studies had emerged to evaluate physical and psychologic risk factors of injury recurrence in this context to facilitate design of prevention programs.
Methods: The present study assessed the incidence of claimed recurrent spinal and new musculoskeletal injuries in a population of 1204 workers. A subgroup of 5.3% (n = 64) of treated patients with a new injury claim in the ensuing 12 months was matched for gender, age, race, length of disability, workers' compensation venue, previous surgery, and litigation status to an identically sized control group who did not report new or recurrent injuries. Demographic, physical, and psychologic measures were obtained prospectively on all patients, before and after treatment, to be analyzed as risk factors.
Results: During the year after treatment, 1.3% (n = 16) of patients reported another injury to the same spinal area, with only a 0.9% (n = 11) recurrent disability rate. A new injury to a different musculoskeletal area was reported by 4.0% (n = 48) of patients. Only 3.4% of the whole cohort, or 64.1% (n = 41) of the sample reporting reinjuries after returning to work, experienced lost work time (i.e., disability) after the reinjury. Only a modest predictive association was found between risk for new or recurrent injury and two self-report indices.
Conclusions: The present study suggests that even a sample of the most severe chronic disabling spinal disorder workers' compensation patients who complete a tertiary functional restoration program are at relatively low risk for either a recurrent spinal disorder or new musculoskeletal injury claim (with or without disability). No major physical or psychologic risk factors for recurrent injury could be identified in this large cohort. These findings argue powerfully against employer bias in not rehiring employees with previous chronic disabling spinal disorder or discriminating in pre- or reemployment on the basis of putative reinjury risk factors after an appropriate rehabilitation program. Literature review documents a surprising paucity of quality studies examining variables predictive of this important socioeconomic outcome variable.