Operated lumbar disc herniation: epidemiological aspects.

A total of 1011 operations for lumbar disc herniation were carried out in South-West Finland during the period 1975-1979. Of these operations 907 were first and 104 reoperations. Eleven patients had cauda equina symptoms. There were 856 operations performed on patients living in the area served by Turku University Central Hospital, an area with 455 000 inhabitants. Operations on 778 patients (342 women and 436 men, mean age 41.6 years) were first and operations on 78 patients (36 women and 42 men, mean age 42.7 years) were reoperations (9.1%). Nearly 90% of the patients were between 25 and 54 years of age. Neither heavy nor light work was more common among the first operated or reoperated patients than in the population at large. The monthly variation in the number of operations had no statistical significance. The incidence of operation for first lumbar disc herniation varied yearly from 31 to 36 per 10(5) persons living in the Turku University Central Hospital area.