Flank Muscle Volume Changes After Open and Laparoscopic Partial Nephrectomy

Purpose: To determine the occurrence of flank symptoms, flank muscle atrophy, bulge, and hernia formation after open and laparoscopic partial nephrectomy (LPN). Patients and Methods: Our prospective Institutional Review Board-approved database was queried to identify 50 consecutive patients who were treated with open partial nephrectomy (OPN) and 50 consecutive patients who were treated with LPN between September 2006 and May 2008. Study patients had: Solitary clinical T1 renal tumor, preoperative and =6 month postoperative CT scan performed at our institution, and a confirmed renal-cell carcinoma on the final pathology report. Patients with previous abdominal surgery and neuromuscular disorders were excluded. Oncocare software was used to measure abdominal wall musculature on preoperative and postoperative CT scan. Bilateral flanks were compared for muscle volume, bulge, and hernia. Patients were administered a phone questionnaire to assess postoperative flank symptoms. Results: No statistical significant difference was found in the demographics between the two groups. Median age (range) was 59.9 years (20.6-80.7) in the OPN group and 57.5 years (25-78) in the LPN group (P=0.89). Median (range) body mass index and American Society of Anesthesiologists scores were similar between the two groups. On CT scans, median percent variation (range) in abdominal wall muscle volume was significantly greater in the OPN group: -1.03% (-31.4-1.5) vs-0.39% (-5.2-1.8) (P=0.006). The median extent of flank bulge on CT scans (range) was also greater in the OPN group: 0.75cm (-1.9-7.6) vs 0cm (-2.7-2.8) (P=0.0004). The OPN group was also more symptomatic, including paresthesia 48% vs 8% (P=0.0053); numbness 44% vs 0% (P=0.002); and flank bulge 57% vs 12% (P=0.007). Conclusions: Minimally invasive partial nephrectomy has lesser deleterious impact on flank muscle volume compared with OPN with fewer symptoms of flank bulge, paresthesia, and numbness.