Date of Award


Degree Type


Degree Name

Master of Science (MS)


Design, Measurement and Evaluation; Clinical Epidemiology and Health Care Research


D.L. Sackett


Many people suffer from some form of low back pain during their lifetime. A well designed morbidity study of general practice in England; using data collected from over 100 general practices, showed the incidence to be 1.6% per year and the prevalence to be 17.5% (62). Severe back pain may necessitate job changes or even job loss.

Forty-two million dollars were spent on industrial back injuries during 1974 in Ontario (86).

Review of the literature is hampered by the fact that only in a minority of cases can a diagnosis be made with any degree of certainty based on knowledge of pathophysiological mechanisms. Perhaps even less relisble is the chance that the doctor may know some therapy which will actually be superior to the spontaneous recovery rate. The spontaneous recovery rate is estimated at 70% after three weeks of symptoms (76). Because of the lack of progress in the area of diagnosis and treatment many studies lack methodological rigor.

This thesis attempts to examine and summarize some of the physiological, anatomical and mechanical factors that may be implicated in the etiology of low back pain and serve as a basis for rational therapy. It also reviews the encouraging advances in basic research which have taken place in the last decade.

In an effort to determine whether proven clinical outcomes occur, with certain standard treatment regimes, a randomized clinical trial is proposed to test the effectiveness of four different programs in a two by two factorial design. All participants will receive analgesics and/or anti-inflammatory agents at the discretion of their family physician. One group will receive no further treatment. The remaining three groups will have bed rest alone, bed rest with physiotherapy, or physiotherapy alone.

Baseline measurements will be obtained by objective methods of assessing spinal flexion, pain, and activities of daily living.

Prior to the commencement of the trial the study population will be divided into two prognostic groups by the method center based on the decision of the family physician to give the patient either major anti-inflammatory medication or minor analgesics.

It is expected that about 260 subjects suffering from low back pain will be identified by five groups of family physicians within a period of six months. For the patients receiving physiotherapy the same physiotherapist will visit each of the five groups two half-days a week in order to supervise the treatment. Compliance with medication will be assessed by pill counts.

Assessment of bed rest compliance will be measured by self-reporting, reports from a friend and a home visit.

One month after treatments begin, another family physician who is blind as to which group the patient is in will perform some of the outcome measures. Outcome results will consist of relief of pain, return to work, return to normal activities, and relapse rate up to three months.

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