Tissue-shrinkage correction factor in the calculation of prostate cancer volume.

Many studies that have calculated prostate cancer volumes from microscopic slides have used correction factors, ranging from 1.22 to 1.5, to compensate for tissue shrinkage during tissue processing. We undertook a study to measure tissue shrinkage directly because our experience suggested less shrinkage than that reported by others. Ten prostatectomy specimens were processed in a uniform manner. Multiple identical linear measurements were taken at four stages of processing: in the fresh state, following fixation, following processing, and from the microscopic slide. Linear shrinkage following fixation was minimal (4.1%) but increased to 14.5% following tissue processing. With rehydration and expansion on the flotation bath, tissues swelled so that net linear tissue shrinkage was 4.3%, and net volumetric tissue shrinkage was 12.4%, which translates into a correction factor for tissue shrinkage of 1.14. The following variables had no statistically significant effect on shrinkage: concentration of formalin, whole-mount versus quadrant sections, thickness of tissue slices, length of time in the alcohol dehydration steps, and temperature of the flotation bath over a range of 35 to 45 degrees C. This study suggests that (a) tissue-shrinkage correction factors that have been used in some previous studies may not be applicable for all laboratories because of interlaboratory variations in tissue-processing procedures or differences in measuring shrinkage; and (b) some calculated tumor volumes that have been used for prognostic thresholds may be high because of inflated tissue-shrinkage correction factors.

Medication use for low back pain in primary care.

STUDY DESIGN: A longitudinal observational study of primary care patients with low back pain. OBJECTIVES: 1) To describe medications prescribed for back pain, 2) to identify patient characteristics associated with type of drug therapy, 3) to determine if the prescription of certain drugs is associated with better outcomes, and 4) to compare physician prescribing behavior with national guidelines. SUMMARY OF BACKGROUND DATA: Few previous studies have focused on medication prescribing patterns for back pain in primary care. METHODS: Two-hundred nineteen patients aged 20-69 years who were making a first visit for an episode of back pain were studied. After the visit, patients completed questionnaires regarding sociodemographic characteristics, health status, back pain experience, and use of medications. Symptom severity and dysfunction were assessed by telephone 1 week after the visit. RESULTS: Sixty-nine percent of patients were prescribed nonsteroidal anti-inflammatory drugs, 35% muscle relaxants, 12% narcotics, and 4% acetaminophen. Twenty percent received no medications. Patients were more likely to receive medications if they had a desire for medication, pain below the knee, less than 3 weeks of pain before visit, more severe symptoms, or greater dysfunction. Patients with more severe symptoms were more likely to receive narcotics or muscle relaxants. Patients with greater dysfunction were also more likely to receive narcotics. Type of drug therapy predicted symptom severity but not dysfunction after 1 week. Controlling for other factors, those receiving medications had less severe symptoms after 1 week than patients who received no medication. Patients receiving both muscle relaxants and nonsteroidal anti-inflammatory drugs had the best outcomes. Medication use for back pain in this health maintenance organization was generally concordant with national guidelines. CONCLUSIONS: Nonsteroidal anti-inflammatory drugs, often augmented by muscle relaxants, are a standard medical treatment for back pain in primary care. In this observational study, patients prescribed medications, particularly muscle relaxants, reported less severe symptoms after 1 week than those receiving no medications. However, randomized trials are needed to determine which medication or combinations of medications are most effective.

Managing low back pain: attitudes and treatment preferences of physical therapists.

BACKGROUND AND PURPOSE: We surveyed physical therapists about their attitudes, beliefs, and treatment preferences in caring for patients with different types of low back pain problems. SUBJECTS AND METHODS: Questionnaires were mailed to all 71 therapists employed by a large health maintenance organization in western Washington and to a random sample of 331 other therapists licensed in the state of Washington. RESULTS: Responses were received from 293 (74%) of the therapists surveyed, and 186 of these claimed to be practicing in settings in which they treat patients who have back pain. Back pain was estimated to account for 45% of patient visits. The McKenzie method was deemed the most useful approach for managing patients with back pain, and education in body mechanics, stretching, strengthening exercises, and aerobic exercises were among the most common treatment preferences. There were significant variations among therapists in private practice, hospital-operated, and health maintenance organization settings with respect to treatment preferences, willingness to take advantage of the placebo effect, and mean number of visits for patients with back pain. CONCLUSIONS AND DISCUSSION: These variations emphasize the need for more outcomes research to identify the most effective treatment approaches and to guide clinical practice.

Surgery for herniated lumbar discs: a literature synthesis.

OBJECTIVE: To assess the risks and benefits of surgery for herniated lumbar discs (discectomy) and to evaluate the methodologic quality of the literature. DESIGN: Literature synthesis. STUDY SELECTION AND DATA ANALYSIS: A structured MEDLINE search identified studies of standard, microsurgical, or percutaneous discectomy. Eligible studies had adult subjects, sample sizes of > or = 30, clinical outcome data for > or = 75% of patients, and follow-up of > or = 1 year. Summary rates of successful outcomes, reoperations, and complications were obtained by a random-effects logistic regression model. Methodologic quality was assessed using established study design criteria. RESULTS: Eighty-one studies met inclusion criteria. Most had substantial design flaws and/or omitted important clinical data. Randomized trials of standard discectomy showed better short-term sciatica relief following surgery; 65% to 85% of patients reported no sciatica one year after surgery, compared with only 36% of conservatively treated patients. No data from randomized trials were available for microdiscectomy or percutaneous discectomy, although most outcomes appeared comparable to those of standard discectomy. Approximately 10% of discectomy patients underwent further back surgery, and rates increased over time. The rate of serious complications, including death and permanent neurologic damage, was less than 1%. CONCLUSIONS: Most studies were poorly designed and reported. Standard discectomy appears to offer better short-term outcomes than does conservative treatment, but long-term outcomes are similar. Discectomies are relatively safe procedures, though reoperations are common and increase over time. Decisions for elective surgery must balance faster pain relief against the risks and costs of surgery.