Conversion During Laparoscopic Surgery: Frequency, Indications and Risk Factors

Purpose: There are limited data on the indications for open conversion during laparoscopic surgery. The frequency of conversion for various procedures is poorly quantified and the degree to which this changes with time is not well understood. Risk factors for conversion are not defined. We addressed these issues in a large series of laparoscopic operations. Materials and Methods: We reviewed our database of 2,128 laparoscopic operations performed between 1993 and 2005, including radical nephrectomy in 549 patients, simple nephrectomy in 186, partial nephrectomy in 347, donor nephrectomy in 553, pyeloplasty in 301, nephroureterectomy in 106 and retroperitoneal lymph node dissection in 86. Open conversions were identified and the frequency of conversion for the total cohort and specific procedures was determined. Trends in conversion with time were assessed and indications analyzed. Clinicopathological features between patients requiring conversion and those who did not were compared. Results: We identified 68 patients (3.3%) who underwent conversion to open surgery (group 1) and 2,011 (96.7%) who did not (group 2). The frequency of conversion was greatest during nephroureterectomy (8.49%), followed by simple nephrectomy (5.91%), retroperitoneal lymph node dissection (4.65%), partial nephrectomy (4.32%), radical nephrectomy (2.91%), donor nephrectomy (2.53%) and pyeloplasty (0.33%). The absolute number of conversions and conversions/cases performed per year decreased significantly with time, reaching a nadir of less than 1% per year. Conversion was inversely related to case volume and cumulative experience. Indications included vascular injury in 38.5% of cases, concern with margins in 13.5%, bowel injury in 13.5%, failure to progress in 11.5%, adhesions in 9.6%, diaphragmatic injury in 1.9% and other in 11.5%. The distribution of indications remained similar with time. There were no differences in patient age, gender, surgical history, American Society of Anesthesiologists score or tumor stage between groups 1 and 2. In groups 1 and 2 mean operative time was 304 vs 219 minutes and estimated blood loss was 904 vs 255 cc (each p <0.0001). Conclusions: The rate of conversion during laparoscopic surgery is not uniform across procedures and it is important for patient counseling. The most common indication for conversion is vascular injury. Importantly the frequency of conversion is dynamic and likely related to case volume and cumulative experience.