Subcutaneous bupivacaine infiltration and postoperative pain perception after percutaneous nephrolithotomy.

Purpose: Recent studies have shown a significant decrease in patient reported pain scores when the nephrostomy tube size is decreased from 22 to 10Fr. We hypothesize that patient reported pain and narcotic use could be further decreased for patients with post-percutaneous nephrolithotomy nephrostomy tubes if the incision is infiltrated with a local anesthetic.
Materials and Methods: A randomized prospective trial was designed to assess the impact of Marcaine infiltration of the nephrostomy tract following percutaneous stone removal. Patients undergoing single access percutaneous nephrolithotomy were randomized to have a fixed volume of saline or weight based concentration of Marcaine infiltrated into the nephrostomy tube tract at the conclusion of the procedure. Postoperative narcotic use and patient reported pain scores were then obtained at 2, 4, 24 and 48 hours postoperatively.
Results: A total of 25 patients were enrolled in the study with 3 excluded from analysis due to incomplete data collection (2) or the development of hydrothorax (1). Of the 22 patients analyzed 10 were in the Marcaine cohort and 12 were in the saline cohort. Patient pain scores at 2, 4, 24 and 28 hours for the Marcaine group were 5, 4.2, 3.6 and 2.6, while for the saline group scores were 3.3, 3.1, 2.3 and 3.5. At all points differences between the groups were not statistically significant (p >0.05). Mean postoperative narcotic use was 24.7 mg morphine sulfate in the Marcaine group and 32.1 mg morphine sulfate in the control cohort (p >0.05).
Conclusions: In this preliminary pilot study no significant differences in patient reported pain scores were observed. However, a trend toward decreased postoperative narcotic use was seen in patients receiving subcutaneous Marcaine administration around the nephrostomy tube tract. Further studies are warranted to define additional measures to reduce discomfort in those requiring nephrostomy tube drainage following percutaneous nephrolithotomy.