Volume of procedures and risk of recurrence after repair of groin hernia: national register study.

OBJECTIVE To determine whether the association between volume and outcome found in major surgery also holds true for a minor operation. DESIGN Review of outcomes after hernia surgery in Sweden. SETTING Surgical units registered with the Swedish hernia register, which in 2004 covered about 95% of all hernia operations in Sweden. PARTICIPANTS 86,409 patients over 15 years, who underwent 96,601 unilateral or bilateral groin hernia repairs (94,077 inguinal and 2524 femoral) in 1996-2004 at the participating surgical units. MAIN OUTCOME MEASURE Re-operation for recurrence. RESULTS There was a significantly higher rate of re-operation in surgeons who carried out 1-5 repairs a year than in surgeons who carried out more repairs. There was no association between outcome and further increases in volume. Although about half of surgeons in Sweden who repair hernias are low volume operators, they performed only 8.4% of all repairs. CONCLUSIONS Sweden's numerous low volume hernia surgeons perform such a small proportion of all operations that the impact of their inferior results on the nationwide re-operation rate is minimal. Volume indicates an approximate minimum value for the number of hernia repairs a surgeon should do each year but the outcome in surgeons who carry out more than that number disqualifies volume as an indicator of proficiency.