Fig. 1.

Progressive changes in clinical manifestations after multiple recurrences.

Duration between revision operations and subsequent recurrences tended to shorten as the number of previous revisions increased (P=0.06). The percentage of patients with a malignant tumor at revision surgery was higher than at initial operation (P=0.04). The general trend toward an increased risk of further recurrence after repeated surgery was significant (P<0.01), despite our finding of a lower risk at the third than at the second operation.