This prospective, randomized study was conducted at Ain Shams University Hospital from December 2019 to July 2020. After approval of the Research Ethics Committee of Ain Shams University in December 2019, the study was registered at https://clinicaltrials.gov/ct2/show/NCT04215705. As the study was conducted during the COVID-19 pandemic, patients were screened before surgery by complete blood picture (CBC) for lymphopenia, Ct Chest for ground glass appearance, and PCR for viral antigen. COVID-19 patients were postponed and excluded from the study. Eighty adult patients aged 21-60 years, both American Society of Anesthesia (ASA) physical status I and II, scheduled for PCNL surgery were invited to enroll in this study.
Preoperative investigations for all patients included routine clinical examinations and laboratory investigations CBC, prothrombin time (PT) and partial thromboplastin time (PTT), INR and ECG. Patients with bleeding disorders, allergies to local anesthetics, psychiatric patients, and those who refused to share in the study were excluded. Patients were reviewed by an anesthesiologist on the same day of surgery for any medical history to ensure fasting for at least 6 hours. The anesthesia plan and VAS score were discussed with the patient, and then they signed a formal consent form.
All patients received general anesthesia, standard monitoring include ECG, NIBP, ETCO2, SPO2 were applied, General anesthesia was induced with Propfol (2mg/kg), fentanyl (1ug/ kg) Atracurium (0.5mg/kg) then intubation was done with endotracheal tube, ventilation was controlled mechanically with tidal volume (6-8 ml/kg), FiO₂ (0.6), rate of ventilation was adjusted to maintain end tidal Co2 in range of 35-45mm Hg. Pantoprazole (40 mg) IV infusion and Granisetron (1 mg) slowly IV were given. Patients were turned to prone position and GA was maintained with isoflurane 2 MAC% and atracurium 0.1mg/kg every 20 minutes.
At the end of the surgery, patients were randomly divided into two equal groups using computer generated table, placing them in a sealed envelope and then opening the envelope in the OR. Group Q, received Quadratus Lumborum Block III, Group P received Peritubal Local Infiltration. In Group (Q) patients were placed in the semilateral position so that the related kidney was in an upside position for the Quadratus Lumborum block which was performed by the primary investigator. After cleaning the surgical field with Povidone Iodine Solution A broadband (5–2 MHz) curved array transducer (sonosite M-Turbo®) was used, and the probe was positioned at the level of the anterosuperior iliac spine and moved upward until the three muscles of the abdominal wall were defined clearly. The hook sign was identified by visualizing the posterior border of the external oblique muscle, leaving below the internal oblique muscle, and over the Quadratus Lumborum muscle. A hyperechoic line appears by tilting the probe down this line represents the intermediate layer of thoracolumber fascia. A 21-gauge 4-inch Stimuplex A needle; B. Braun Medical Inc., Melsungen, Germany) was introduced in plane from anterior to posterior by hydrodissection at the fascial plane between the QL and Psoas muscle with 20 ml of 0.25% bupivacaine on in the side of PCNL.[11]
In group (L), while the patient was still in the prone position, a spinal needle 22-gauge 2-inch Stimuplex A needle; B. Braun Medical Inc was inserted along the nephrostomy tube by the urologist under fluoroscopy in the 6 and 12 o’clock positions, and the renal capsule was contacted. A total of 20 ml bupivacaine 0.25% was infiltrated along the renal capsule, muscle, subcutaneous tissue ,and the skin as described by Parikh et al.[12]. In both, groups patients were turned to the supine position, and recovery from GA was performed with 2.5 mg neostigmine and 1 mg atropine to antagonize the action of the muscle relaxant. Extubation was performed after fulfillment of the needed criteria, and the patient was moved to the postanesthetic care unit (PACU).
The postoperative analgesic strategy included 1-gram paracetamol given before extubation, which was repeated every six hours postoperatively. Additionally, patients were given IV ketorolac 10 mg every 8 hours starting immediately after surgery. Patients in both groups were connected to a PCA machine containing morphine with a bolus dose of 1 mg boluses, lockout interval 6 min with no basal rate, and maximum 100 mg/24 h. Patient was instructed to use PCA for VAS>4.
Measured parameters
Postoperative pain was assessed as the primary outcome both at rest and during movement or cough (dynamic) by an independent observer who was blinded to the procedure to avoid detection biases. The Visual analog scale (VAS) was used with a scale from 0 to 10, where 0 means no pain and 10 means unbearable pain, and it was measured at 1, 2, 4, 6, 12, and 24 hours postoperative. Other variables were recorded as a secondary outcome, such as total morphine consumption during the first 24 hours, first use of PCA, occurrence of complications such as nausea, vomiting or pruritus and patient satisfaction score.
Statistical Analysis
The collected data were organized, tabulated and statistically analyzed using SPSS software statistical computer package version 22 (SPSS Inc, USA). The Shapiro-Wilk test was used as test of normality. Numerical variables such as age, weight, height, BMI, surgery duration, stone size and first time to request analgesics were normally distributed and are described as the mean ± standard deviation (SD). An independent t-test was used to compare the mean values of the two groups. Other variables were not normally distributed and were presented as median and interquartile range (IQR); Mann-Whitney U test was used as a test of significance. Linear mixed models were used to account for repeated measures of VAS scores. A fixed effect model was used for the group, and a random effect model was used to adjust for repeated measures over time. The time-to-event variables were evaluated using the Kaplan-Meier method, and the logrank test was used to compare the groups. Qualitative data are presented as numbers and percentages, and the chi-squared test was used to determine significance. A two-sided P-value of <0.05 was considered statistically significant. P<0.01 was considered significant when multiple comparisons were performed for pain scores at rest and movement
Previous studies detected a 40% difference in VAS score between the study groups, which is the primary outcome in our study[10, 11], G* power computer program version 3.1.9.2 was used to calculate the sample size required with 80% power, an alpha error of 0.05 and allocation ratio of 1.[13] A sample size of 37 patients was calculated per group. To compensate for drop outs the sample size was increased to 40 patients in each group.