Efficacy of incisional infiltration and intraperitoneal instillation of ropivacaine for the management of pain after laparoscopic sleeve gastrectomy

Editor, Although the induction of laparoscopy in bariatric surgery has led to faster recovery, postoperative pain remains an issue.1 The aim of this prospective, randomised, double-blinded, placebo-controlled trial was to evaluate incisional infiltration and intraperitoneal installation of ropivacaine on optimising analgesia after laparoscopic sleeve gastrectomy (LSG). The study was approved by the Ethics Committee of Hippokration General Hospital (no. 75/2011) on 2 December 2011 and was carried out according to the principles of the Declaration of Helsinki, 7th revision, Fortaleza 2013. Informed consent was signed pre-operatively by all patients. Patient enrolment is depicted in Fig. 1. Inclusion criteria were BMI more than 40 kg m−2 or more than 35 kg m−2 with relevant comorbidities. Exclusion criteria were American Society of Anesthesiologists (ASA) physical status more than 2, age less than 18 or more than 60 years, allergy to local anaesthetics and simultaneous operation of another type. Sample size was calculated by power analysis: with α = 0.05, β = 0.20, SD = 20 and significant Visual Analogue Scale (VAS) score difference of 10 calculated n was 60, based on a pilot study of 21 participants. Patients and staff, including those who collected the data, were blinded to the study.Fig. 1: Consort flow diagram of patient enrolment Saline, 0.9% saline.A total of 60 patients operated from January till June 2012 were randomised into three groups: Group A received incisional infiltration with 20-ml ropivacaine 0.5% and intraperitoneal instillation with 20-ml ropivacaine 0.5%, Group B incisional infiltration with 20-ml ropivacaine 0.5% and intraperitoneal instillation with 20-ml 0.9% saline and controls incisional infiltration with 20-ml 0.9% saline and intraperitoneal instillation with 20-ml 0.9% saline. Intraperitoneal instillation was administrated though a temporary catheter after specimen removal in the subdiaphragmatic space over the gastro-oesophageal junction and along the staple-line. Differences in VAS scores at rest and cough were the primary endpoints. Fentanyl consumption and additional analgesia demand (lornoxicam or meperidine) were the secondary. VAS scores were recorded in the recovery room and at 2, 4, 6, 12, 18, 24, 32, 40 and 48 h. Heart rate (HR), DBP, SBP and arterial SO2 were recorded the day before, in recovery room and at 2, 6, 12, 24, 32 and 48 h. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were recorded before the operation and at 24 h. To determine within group and between group differences, the Analysis of variance (ANOVA) for repeated tests was used with Bonferroni correction adjusted for multiple comparisons. Categorical data were analysed with χ2 test with Fisher's exact test when applicable, and the level of significance was set at 0.05. A 5-trocar technique was used and the specimen was extracted from the extended 12-mm trocar site. Patient-controlled analgesia (PCA) was used for postoperative analgesia, programmed to deliver 2 to 3 ml h−1 background fentanyl infusion and 1-ml bolus doses (10-min lockout interval), with parecoxib 80 mg/24 h and paracetamol 3 g/24 h. Patients’ characteristics are summarised in Table 1. No major postoperative complications or ropivacaine adverse effects were observed. VAS scores differed significantly during the first hours, and when post hoc multiple comparisons were performed, significantly lower VAS scores were observed in Groups A and B compared with controls, but no statistically significant differences were recorded between Groups A and B (Fig. 2). Group A presented lower VAS scores at rest in the recovery room (30.0 vs. 53.8, P < 0.01), at 2 h (21.8 vs. 33.8, P = 0.04), 4 h (20.7 vs. 30.6, P = 0.02) and 6 h (18.2 vs. 24.8, P = 0.05), compared with controls. Group B presented lower VAS scores at rest at the same time points compared with controls: 36.5 vs. 53.8 in the recovery room (P < 0.01), 25.5 vs. 33.8 at 2 h (P < 0.01), 20.0 vs. 30.6 at 4 h (P < 0.01) and 15.0 vs. 24.8 at 6 h (P < 0.01). Both groups presented lower VAS scores at cough over the first 4 h: in the recovery room Group A had 40.5 vs. 67.6 in controls (P < 0.01), whereas group B had 49.0 (P < 0.01), at 2 h Group A had 28.8 and Group B 30.0 compared with 42.2 in controls (P = 0.01 and 0.01) and at 4 h the difference was 25.7 vs. 38.0 (P = 0.05) and 26.2 vs. 38.0 (P = 0.02). At 6 h only the difference between Group B and controls remained (26.2 vs. 34.3, P = 0.02).Table 1: General characteristics of the patients, fentanyl consumption and percentage of patients that requested extra analgesiaFig. 2: Mean postoperative VAS scores at rest and cough. VAS, visual analogue scale.Fentanyl consumption in controls was 1126 μg, higher than Group A (902 μg, P = 0.02) and Group B (869 μg, P = 0.02). Moreover, 20% of controls asked for extra analgesia in the ward compared with 4% in Groups A and B (P = 0.02). SBP was lower in Group A compared with controls at 2 h (134.7 vs. 144.7 mmHg, P = 0.04) and at 12 h (132.1 vs. 147.1 mmHg, P = 0.03), whereas Group B presented also lower SBP compared with controls at 2 h (134.8 vs. 147.8 mmHg, P = 0.01) and 4 h (134.1 vs. 142.2 mmHg, P = 0.04). SBP did not differ between Groups A and B. SO2, HR, FEV1 and FVC did not differ between groups. Ropivacaine has been evaluated in laparoscopic procedures such as colectomy, hernia repair, cholecystectomy and appendicectomy.1,2 Most evidence comes from laparoscopic cholecystectomy studies with contradictory results.3 Our results are in line with authors supporting the efficacy of incisional infiltration and the inefficacy of intraperitoneal instillation on postoperative pain.4 Differences in type, concentration, volume and timing of instillation could explain the diversity of results. The use of local anaesthesia in LSG remains rather underinvestigated. The only available evidence on the use of local anaesthetics in laparoscopic bariatric surgery comes from some studies on laparoscopic gastric bypass (LGBP) or mixed groups of bariatric surgery patients.1,5 Omar and Abualsel6 reported lower early postoperative VAS scores after intraperitoneal installation of bupivacaine in bariatric surgery patients undergoing LSG, LSG with cardioplasty and LGBP. Nevertheless, according to our study additional intraperitoneal installation does not offer any advantage over incisional infiltration. The different anaesthetic used, the lack of incisional infiltration and the existence of patients undergoing cardioplasty, hiatal hernia repair, laparoscopic cholecystectomy or adhesiolysis, which may increase visceral pain, could explain the different results. Ruiz-Tovar et al.7 reported that intraperitoneal infusion with ropivacaine combined with bupivacaine incisional infiltration in bariatric surgery was associated with reduced pain and morphine needs. However, VAS scores were recorded at 24 h, PCA was not used, the amount of ropivacaine was larger and most patients underwent LGBP. LSG is a shorter procedure and a trocar site is extended to remove the specimen, enhancing the parietal pain, whereas in LGBP the peritoneal distension is longer and usually two anastomoses are created, which may increase visceral pain and lead to a more effective impact of intraperitoneal installation. In these two studies LSG patients were not studied separately, making the comparisons difficult. To our knowledge there is not yet a similar trial in a homogeneous LSG group. Conclusively, incisional infiltration was associated with reduced VAS scores, lower fentanyl consumption and lower request for additional analgesia, suggesting that a combined analgesic regimen that includes incisional infiltration with ropivacaine will be highly useful and well tolerated for soothing early postoperative pain after LSG, whereas intraperitoneal installation does not seem to offer additional benefit. Further Randomised controlled trials using different volumes and concentrations of ropivacaine or other anaesthetics are required to further evaluate our findings. Acknowledgements relating to this article Assistance with the letter: none. Financial support and sponsorship: none. Conflicts of interest: none.