The effect of local anesthetic infiltration around nephrosomy tract on postoperative pain perception after percutaneous nephrolithotomy

Objective: Most of the pain after percutaneous nephrolithotomy (PNL) is experienced due to dilatation of the renal capsule and parenchymal tract. Previous investigations have focused on the impact of nephrostomy catheter size on postoperative pain and the effect of local anesthetic infiltration to the surgical field has not been well established for PNL. The aim of this study was to investigate the effect of a long acting local anesthetic infiltration around nephrostomy tract on pain control after PNL.Material and Methods: Forty-six adult patients with kidney stones of > 2 cm undergoing single access subcostal PNL were enrolled in the study. Patients were randomized in a single blinded fashion to levobupivacaine (study group) and saline (control) infiltration groups. Study group patients (n=23) had 25mg/10cc levobupivacaine infiltration with a 21 G needle into the subcutaneous tissues around the access site after placement of 20 F re-entry Malecot catheter. Levobupivacaine injected along the nephrostomy tube in order to let the drug to diffuse partly outside the renal capsular surface. Control group patients had 10 cc saline infiltrated with the same technique. Postoperatively the patients were given narcotics on demand. Pain scores were collected using a 10 cm visual analog scale (VAS) with ?0? being no pain and ?10? being the worst pain experienced by the patient at 2nd, 4th, 6th, 8th and 24th hours postoperatively. The VAS scores, time to analgesic demand, total narcotic analgesic dose, time of oral intake and time of mobilization were compared between two groups.Results: The mean age was 44 and 45 years and the mean body mass index was 26 and 25 for study and control groups. The mean stone surface area, operation time and irrigation fluid amounts for study and control groups were 508 and 473 mm2; 103 and 99 minutes; and 12.5 and 11,8 L, respectively (p=0.54, p=0.74 and p=0.71, respectively). Success and complication rates were similar for the both groups. Comparison of pain scores at all postoperative time points was not statistically significant between two groups. Time to first analgesic demand and total narcotic analgesic dose per patient were 1.2±1.05 and 4.04±1.57 hours; and 96 mg and 112 mg for study and control groups (p=0.009 and p=0.41, respectively).Conclusion: Infiltration of nephrostomy tract site with levobupivacaine does not have an effect on postoperative pain control in patients undergoing PNL. However, levobupivacaine infiltrated patients had a trend toward using analgesics in a later period.