UBC Theses and Dissertations
Utilization, access and outcome of surgical lumbar discectomy in British Columbia Quon, Jeffrey
Lumbar discectomy is the most commonly performed operation on the spine. This thesis includes four studies on the utilization, access and outcome of lumbar discectomy in British Columbia. Studies 1 and 2 estimate temporal trends and regional variations in age- and sex adjusted lumbar discectomy rates using administrative data from the BC Linked Health Database. Study 1 shows that discectomy rates in public hospitals declined by 61% between 1990/91 and 2003/04. Rates declined faster after 2000/01 when lumbar discectomy became accessible in private clinics, preferentially for workers' compensation beneficiaries. Evidence of the diversion of compensated surgical patients from the public to private sectors was observed, however with no obvious attenuation of the decline in surgical rates for noncompensated patients remaining in the public system. In Study 2, rates of lumbar discectomy varied significantly between health service delivery areas (HSDAs), by almost five-fold during 2000/01-2003/04, up from 3.4 fold in 1990/91-1993/94. Studies 3 and 4 are based on prospective registry data on surgically treated lumbar disc patients at Vancouver General Hospital between November 1999 and December 2003. Study 3 identified significant sociodemographic and clinical determinants of waiting times in this population. Clinical severity (symptom duration, pain intensity) were appropriately associated, while most sociodemographic variables (age, sex, compensation status) were appropriately not associated with access to surgery. However professional occupation predicted waiting time, suggesting that access to surgery may not be based on clinical need alone. Study 4 estimated the effect of waiting 12 weeks or longer on the odds of pain improvement after lumbar discectomy. In propensity score-adjusted ordinal regression models, patients waiting 12 weeks or longer for surgery had a 41% lower odds of pain improvement. In the absence of declining disease prevalence, the implications of declining back surgery rates possibly include declining access to care and rising prevalence of disability in the community. This thesis research indicates that delayed access matters, and that "treatment within 12 weeks" may have utility as both a quality-of-care measure in health services research and as a benchmark for defining a maximum appropriate wait for lumbar discectomy.
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