Ultrasound guided peritubal infiltration of 0.25% Bupivacaine versus 0.25% Ropivacaine for postoperative pain relief after percutaneous nephrolithotomy: A prospective double blind randomized study.

BACKGROUND AND AIM: Percutaneous nephrolithotomy (PCNL) is a common for managing renal calculi. Pain in the initial post operatie period is relieved by infiltration of local anaesthetic around the nephrostomy tract. We aimed to compare the analgesic efficacy of bupivacaine and ropivacaine.
METHODS: A total of 100 adult patients undergoing elective PCNL-under balanced general anaesthesia were randomly divided into bupivacaine group (Group B) and ropivacaine group (Group R). After completion of procedure, 23G spinal needle was inserted at 6 and 12 O'clock position under ultrasonic guidance up to renal capsule along the nephrostomy tube. A volume of 10 ml of either 0.25% bupivacaine or 0.25% ropivacaine solution was infiltrated in each tract while withdrawing the needle. Post-operative pain was assessed using visual analogue scale (VAS) and dynamic visual analogue scale (D-VAS) for initial 24 h. Intravenous tramadol was given as rescue analgesia when VAS >4. Time to first rescue analgesic, number of doses and total amount of tramadol required in initial 24 h and side-effects were noted.
RESULTS: Visual analogue scale and D-VAS at 6 h and 8 h in Group B was significantly higher than Group R. Mean time to first rescue analgesia in Group R was significantly longer than Group B. Mean number of doses of tramadol and total consumption of tramadol in 24 h was less in Group R, though not statistically significant.
CONCLUSION: Peritubal infiltration of 0.25% ropivacaine infiltration along the nephrostomy tract is more effective than 0.25% bupivacaine in alleviating initial post-operative pain after PCNL.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is considered as ‘gold standard’ for the management of patients with renal calculi. Placement of nephrostomy tube after PCNL is a standard practice. Tubeless PCNL operations are performed in select cases. Several investigations have focused on the impact of reduced percutaneous catheter size on post-operative pain, analgesic requirements and duration of cutaneous drainage.[1] In PCNL surgery, pain around nephrostomy tube can be distressing. Analgesics like non-steroidal anti-inflammatory drugs and opioids have their own side-effects. Skin infiltration of local anaesthetic drug at the surgical site is not so effective. Infiltration of local anaesthetic from the renal capsule to the skin along the nephrostomy tract has been reported to relieve the initial post-operative pain.[23]

The aim of this study was to investigate and compare the efficacy of peritubal infiltration of two different local anaesthetics, bupivacaine 0.25% versus ropivacaine 0.25% administered under ultrasonic guidance for post-operative pain relief after PCNL and to assess the number of doses as well as total requirement of rescue analgesic in first 24 h of the post-operative period.

METHODS

A prospective randomised double-blind prospective comparative study was conducted from January 2012 to December 2012 in 100 American Society of Anaesthesiologists physical status I-III adult patients posted for PCNL surgery after Institutional Ethics Committee's approval and informed consent. They were randomly divided into two equal groups with 50 patients in each group by closed envelope method. Group B was bupivacaine group (0.25% bupivacaine infiltration), and Group R was Ropivacaine group (0.25% ropivacaine infiltration). Patient's inclusion criteria were 18-60 years of age, 35-85 kg weight having body mass index <30, renal stone size <3.0 cm with a single nephrostomy tube (22 F) and duration of surgery <3 h. Patients having supracostal puncture, excessive bleeding and more than one puncture were excluded from the study. Study drug was prepared by person blinded to the actual study and findings recorded by a third person. All patients were pre-medicated with intravenous ondansetron 8 mg, intravenous fentanyl of 2 μg/kg and intravenous glycopyrrolate 0.04 mg/kg. Balanced general anaesthesia was administered, induction done using thiopentone 5-6 mg/kg and intubation facilitated by succinylcholine 1.5 mg/kg. After endotracheal intubation, patients were maintained with O2/N2O with a muscle relaxant and isoflurane. Surgery was performed in the prone position. After insertion of nephrostomy tube and before the extubation of inserted up to renal capsule under ultrasonographic (Micromaxx® Ultrasound from Sonosite) guidance along the nephrostomy tube at 6 O’clock and 12 O’clock positions. In Group B, 20 ml of 0.25% bupivacaine and in Group R, 20 ml of 0.25% ropivacaine was infiltrated (10 ml in each tract) while gradually withdrawing the needle from renal capsule to the skin thereby infiltrating the renal capsule, perinephric fat, muscles, subcutaneous tissue and skin. Patients were extubated and kept in post-anaesthesia care unit under observation for 24 h.

During follow-up, patients were assessed for pain and side-effects by an independent observer blinded to the infiltration, immediately after extubation, half hourly for 2 h, every 2 hourly for the next 6 h and every 4 hourly until 24 h. The pain score was assessed using 0-10 point visual analogue scale (VAS) at rest and dynamic visual analogue scale (D-VAS) on deep breathing and coughing (0- no pain and 10 - maximum, unbearable pain).

When VAS score >4, the patient was administered intravenous tramadol 1.0 mg/kg slowly as a rescue analgesia, and the patient was reassessed. Maximum 400 mg of tramadol was administered in initial 24 h. Intravenous ondansetron wasgiven if there was nausea and vomiting. Nausea was scored as grade 0-3 where 0 means none and 3 means severe nausea. Time for first demand of rescue analgesic was noted to assess the duration of analgesia. Number of doses of tramadol and total consumption of tramadol required in 24 h were noted.

Statistical analysis was performed using, Statistical Considering a hypothesis that after administration of peritubal local infiltration, the first demand of rescue analgesia was longer by 40%, with a power of 90% and an α error of 0.05, the sample size was estimated as 50 patients in each group. Continuous data were described as mean ± standard deviation and categorical variables are given as number (%). Continuous variables were compared using t-test for two independent samples. Percentages were compared using Chi-square analysis. P < 0.05 was considered to be statistically significant.

RESULTS

There were no dropouts from the 100 patients enrolled in the study. The demographic data regarding age, weight, sex, and duration of surgery were comparable and insignificant [Table 1]. VAS (at rest) and D-VAS (during deep breathing and coughing) were low in both groups in the post-operative period, but significantly lower in Group R as compared with Group B at 6 h and 8 h [Figures 1 and 2]. The mean time for first demand of analgesia was 10.54 ± 2.24 h in Group R and 7.91 ± 1.96 h in Group B (P < 0.0001). The mean number of analgesic demands required during initial 24 h was 2.27 ± 0.49 in R Group and 2.39 ± 1.03 in Group B (P = 0.458). The mean total consumption of tramadol in first 24 h was 122.2 ± 29.01 mg in Group R and 134.3 ± 58.7 mg in Group B (P = 0.194). The side-effects like nausea and vomiting were less and insignificant in both groups [Table 2].

Table 1

Demographic data

Figure 1

Mean visual analogue scale

Figure 2

Mean dynamic visual analogue scale

Table 2

Comparison of rescue analgesic requirement and side-effects

DISCUSSION

Keyhole surgery has replaced open surgery in many surgical fields as it causes less pain and morbidity. In urology, PCNL is emerging as the surgery of choice in most of patients with renal calculi. Placement of nephrostomy tube is the last step in PCNL surgery for good haemostasis and adequate drainage. The nephrostomy tube produces local inflammatory reaction which causes the post-operative pain and discomfort in PCNL. On-going studies aim at decreasing the post-operative pain and morbidity by reducing the size of the working percutaneous tract, a procedure referred to as a ‘miniperc’.[4567] Even tubeless PCNL operations were done by some authors and they have reported decreased pain and analgesic requirements for selected patients.[789] Local anaesthetics can inhibit inflammatory and local sensitising responses by directly suppressing some phases of inflammation like neutrophil priming and by blocking some of the neuronal pathways, which are activated by inflammation involving protein kinase C and G protein-coupled receptors.[10] Haleblian et al.[11] conducted a study on subcutaneous infiltration of 1.5 mg/kg of 0.25% bupivacaine versus saline after PCNL in 25 patients. Their results showed reduced rescue analgesic requirement in bupivacaine group, but no significant difference in pain score was found in both groups. Hence, it was hypothesised that the cause for pain after PCNL surgery, which requires nephrostomy tube, could result from structures beyond the skin puncture site like the renal capsule. Dalela et al.[12] performed PCNL under renal capsular block by infiltrating renal capsule with 2% lignocaine. He emphasised that most of pain during PCNL is felt at the time of dilatation of renal capsule and parenchyma as it is richly innervated by pain conducting neurons. In another study, Aravantinos et al.[13] performed PCNL in two stages in 24 patients. In 1st stage, 16-Fr nephrostomy tube was placed after infiltrating skin site with 2% lignocaine for 1-week. In 2nd stage, after infiltrating the nephrostomy tract with 2% lignocaine, dilatation of the tract was performed and stones were removed. He concluded this to be a safe and effective approach in selected patients. Jonnavithula et al.[2] performed a study for post-operative pain relief using 0.25% bupivacaine infiltration along the nephrostomy tract after PCNL under fluoroscopic guidance. They found lower pain scores and prolonged duration of analgesia in block group than the control group. The mean total consumption of rescue analgesic was less in block group. Gokten et al.[3] compared 0.25% levobupivacaine infiltration plus intravenous paracetamol infusion, saline plus paracetamol infusion and 0.25% levobupivacaine plus saline infusion. They found lesser requirement of opioid (meperidine), lower VAS score, and shorter time to full mobilisation and higher patient satisfaction score in the levobupivacaine plus paracetamol group compared to other two groups. Ugras et al.[14] infiltrated 30 ml of either 0.2% ropivacaine or saline into renal puncture site, nephrostomy tract and skin after PCNL. Their results showed that VAS at 6 h, time to first analgesic demand (8.4 ± 0.6 h) and total analgesic need were significantly lower in ropivacaine group, which correlates with previous studies.[15]

In our study, we have compared the efficacy of two different local anaesthetics that is, bupivacaine and ropivacaine for infiltration along the nephrostomy tract. We found the mean duration of analgesia to be average 10.54 h in Group R and 7.91 h in Group B. Akerman et al.[16] conducted a study on primary evaluation of local anaesthetic properties of ropivacaine and concluded that ropivacaine 0.25-1% was distinctly longer acting than bupivacaine on infiltration. They suggested that ropivacaine was less vasodilative than bupivacaine and capable of producing some vasoconstriction over a wide range of low concentrations, which may explain its longer duration of action. In our study, incidence of side-effects like nausea and vomiting were minimum and insignificant in both groups. The limitation of our study was that we included patients with single punctures with a single nephrostomy tube, thus being unable to evaluate the efficacy of our study when more than one puncture was involved. One more limitation of the study was that there was no control group.

CONCLUSION

Peritubal infiltration with local anaesthetics ropivacaine and bupivacaine under ultrasound guidance provides effective pain relief in the initial post-operative period; however, duration of analgesia as denoted by demand to first rescue analgesic is prolonged with ropivacaine as compared with bupivacaine.