Laparoscopic and Robot assisted renal surgeries have gained prominence due to their minimally invasive nature, offering benefits such as reduced pain, shorter recovery times, and quicker return to daily activities. While these surgeries are minimally invasive, they can still result in significant postoperative pain and therefore postoperative pain management of these patients is very important. Postoperative analgesia is often multimodal in nature and combines medications like opioids, NSAIDs, and regional anesthesia techniques. Recent studies have explored the efficacy of regional anesthetic techniques like Erector Spinae Plane Block (ESPB) and Quadratus Lumborum Block (QLB) in providing postoperative analgesia. (1)
Erector Spinae Plane Block (ESPB) is a relatively new regional anesthesia technique that targets the erector spinae muscle group, allowing for analgesia by depositing local anesthetic in the fascial plane. Literature indicates that ESPB can significantly reduce postoperative opioid consumption and pain scores in patients undergoing laparoscopic renal surgeries. The proposed mechanisms of action include the spread of LAs to paravertebral space, systemic absorption of local anesthetics (LAs), thoracolumbar fascial innervation mediated analgesia and immunomodulatory effects of LAs (2). A study highlighted the potential of ESPB in providing effective analgesia with fewer side effects compared to traditional opioid-based pain management (3).
Quadratus Lumborum Block (QLB) targets the quadratus lumborum muscle and the surrounding fascia, providing a more comprehensive analgesic effect, particularly for abdominal surgeries. Research suggests that QLB is effective in managing postoperative pain following laparoscopic renal surgeries (4). A randomized controlled trial found that patients who received QLB had reduced pain scores and lower opioid requirements in the postoperative period compared to those who received standard analgesia (5).
There is some evidence to suggest that ESPB has better analgesic efficacy as compared to QLB (6). However , comparative studies between ESPB and QLB for laparoscopic renal surgeries are limited. Therefore, this study was planned to assess the analgesic efficacy of ESPB versus transmuscular QLB in laparoscopic/robot assisted renal surgeries. We hypothesize that ESPB is superior to QLB for provision of postoperative analgesia in patients undergoing laparoscopic/robot assisted renal surgeries.
Review of Literature
The use of regional anesthesia techniques for postoperative pain management has gained significant traction in recent years, especially in the context of minimally invasive surgeries. Among these techniques, the Erector Spinae Plane Block (ESPB) and the Quadratus Lumborum Block (QLB) have emerged as effective options for managing postoperative pain in laparoscopic and robot assisted renal surgeries.
Erector Spinae Plane Block (ESPB)
Forero et al. (2016) (7) introduced the ESPB as a novel technique for analgesia in patients undergoing thoracic surgery, as detailed in their study published in Regional Anesthesia and Pain Medicine. They described the method of injecting local anesthetic into the fascial plane deep to the erector spinae muscle, demonstrating its feasibility and effectiveness in providing analgesia while reducing opioid consumption in the postoperative period. The study highlighted two approaches for administering the block: one targeting the interfascial plane between the rhomboid major and erector spinae muscles, and the other directing the injectant deep into the erector spinae muscle. Their findings indicated that the latter approach yielded better analgesic outcomes, a conclusion supported by subsequent literature favoring the deep application method for bilateral ESPB (7).
A systematic review by Gao et al. (8) summarized evidence from multiple studies demonstrating that ESPB effectively reduces postoperative pain and opioid use in diverse surgical populations, including those undergoing abdominal and thoracic procedures. This broad applicability underscores the potential of ESPB in enhancing postoperative care.
Quadratus Lumborum Block (QLB)
Venkatraman et al (5) published a foundational study outlining the technique of QLB, emphasizing its anatomical landmarks and methodology. Their research indicated promising preliminary outcomes, including effective pain relief, decreased opioid requirements, and favorable patient recovery metrics. The authors posited that QLB could be particularly beneficial in managing pain related to various abdominal surgical procedures.
Christopher et al. (9) compared the effectiveness of QLB in patients undergoing laparoscopic nephrectomy and highlighted its role in providing significant postoperative analgesia. The authors reported that QLB not only enhanced pain relief but also contributed to reduced opioid consumption and faster recovery times, reinforcing the technique’s clinical relevance.
Comparative Studies
The comparative efficacy of ESPB and QLB was specifically addressed by Hetta et al (10), who conducted a study evaluating both techniques in patients undergoing abdominal surgeries. Their findings revealed that while both blocks were effective, the ESPB group experienced superior analgesia, particularly within the first 24 hours post-surgery. Patients receiving ESPB required significantly fewer opioids, indicating its potential as a more effective pain management strategy. Additionally, the ESPB group demonstrated a longer duration of analgesia, suggesting its preference in certain surgical contexts.
A recent study by Zhang et al (2024) (6) on a similar topic as this study. A total of 110 patients were enrolled and randomized to receive either erector spinae plane block (n = 55) or quadratus lumborum block (n = 55) under ultrasound guidance. Patient-controlled sufentanil analgesia was provided after surgery. The equivalent dose of sufentanil consumption within 24 h after surgery was lower in patients given ESPB (median 13 µg, interquartile range [IQR] 4 to 33) than in those given QLB (median 25 µg, IQR 13 to 39; median difference - 8 µg, 95% CI -15 to 0; P = 0.041).
Zhang’s study compares the analgesic effects of Erector Spinae Plane Block (ESPB) and Quadratus Lumborum Block (QLB) in patients undergoing laparoscopic renal surgeries. The findings indicate that Compared with quadratus lumborum block, erector spinae plane block provided better analgesia as manifested by lower opioid consumption and pain intensity for up to 24 h after laparoscopic nephrectomy.
Overall, the study underscores the importance of selecting the appropriate regional anesthesia technique to optimize postoperative pain management.
There are certain restrictions on this trial. First, while the blocking operation was carried out by skilled anesthesiologists following the induction of anesthesia, they were unable to ascertain the dermatomal extent of sensory block. Second, anesthesiologists were not disguised from trial intervention for practical reasons. Nevertheless, group assignment was unknown to patients, other healthcare professionals, and investigators in charge of postoperative evaluation. Third, the evaluation of the results may be hampered by intraoperative opioids. However, given the pharmacokinetic profile of sufentanil, this does not appear to endure for more than four hours. Fourth, it became more difficult to calculate opioid consumption since other opioids other than sufentanil were given and converted to sufentanil equivalent during the postoperative period.
AIM AND OBJECTIVES
AIM: To compare the perioperative analgesic effect of erector spinae plane block versus transmuscular quadratus lumborum block in patients undergoing laparoscopic and robot assisted renal surgeries.
Primary outcome: Cumulative PCA fentanyl consumption within 24 hrs after surgery
Secondary outcomes:
1. NRS at rest on coughing at 0.5,1,2,4,8,12 and 24 hours postoperatively
2. Time to activation of PCA
3. Use of rescue analgesia
4. Qor-15 score at 24 and 48 hrs postoperatively
5. Length of hospital stay
6. Time to mobilisation to chair from T0 (Time of arrival to PACU)
7. Time to first walk (10 mtrs) from T0 (Time of arrival to PACU)
8. Incidence and severity of opioid-related adverse effects such as nausea and vomiting, respiratory depression, pruritis and sedation
9. Subjective sleep quality on the night of surgery
10. Baseline and 24 hrs postoperative CRP levels
MATERIALS AND METHODS
STUDY DESIGN
Prospective, double blind, single centre, randomised controlled trial
STUDY SETTING:
Department of Anaesthesiology, Pain medicine and Critical care at AIIMS, New Delhi
STUDY POPULATION
After obtaining the Institutional Ethical Committee approval and written informed consent from the patients, adult ASA I-III patients more than 18 years undergoing laparoscopic or robot assisted renal surgeries in All India Institute of Medical Sciences, New Delhi, will be considered for recruitment in this study.
SAMPLE SIZE CALCULATION
Based on a previous study by Zhang et al (1), we expect a 40% decrease in postoperative opioid consumption in patients with ESPB as compared to QLB. Considering the mean 24 hour fentanyl consumption to be 458.50+/- 246.30 mcg for QLB group according to our previous study (Unpublished data), we are anticipating a difference of 183.40 mcg between ESPB and QLB group with a combined standard deviation of 246.30 mcg. Assuming an alpha error of 0.05 and power of 80%, the estimated sample size is 28 per group. Accounting for a dropout rate of 10%., the final sample size of the study will be 32 patients per group.
INCLUSION CRITERIA
Age: 18 years and above
ASA I-III
Patients scheduled for laparoscopic or robot assisted renal surgeries
EXCLUSION CRITERIA
Allergy to local anesthetics
Inability to communicate
Chronic pain or recent acute pain
Severe liver or renal dysfunction
Long term use of analgesic or sedatives
Refusal to give consent
BMI > 35kg/m2
CONSENT
Consent for the study will be obtained in accordance with the Declaration of Helsinki. The patients will be well informed and explained in their own language that they are participating in a study, the procedure of the study and the chance of being assigned randomly to any one group. They will be explained in person and a written consent will be obtained from the patient. Patients will be made aware of their right to withdraw from the study at any time without any adverse effects on their clinical care.
RANDOMISATION
Randomisation will be achieved using a computer-generated random number table with the allocation ratio of 1:1. Allocation concealment will be maintained using sequentially numbered sealed opaque envelopes. Envelopes will be prepared by an independent person not involved in the study. Each envelope will contain a number which will allocate the participant to either the Group A (ESPB group) or the Group B (TMQLB group). The allocation sequence will be accessed only when study data collection is complete or in any instance where unblinding of the study is thought to be essential in the provision of appropriate patient care.
Group A: (ESPB)
Ropivacaine 0.5% at 0.4ml/kg not exceeding 30ml will be deposited in the fascial plane above the erector spinae muscle at the level of T9 spinous process.
Group B: (TMQLB)
Ropivacaine 0.5% at 0.4ml/kg not exceeding 30ml will be deposited into the interfascial plane that is between the psoas major and QL muscle in L2-L4 level at the posterior axillary line
BLINDING
Envelopes will be opened upon arrival of the patient. Patients will be randomized to receive either ESPB or TMQLB which will be performed before induction by an anesthesiologist not involved in the study. Patients will be unaware of the group allocation. Postoperative outcomes will be assessed by the investigator that remains blinded to the type of intervention.
PREOPERATIVE :
A detailed routine preoperative evaluation will be done one day prior as per standard practice. An Informed consent will be obtained from the patient. All selected patients will undergo a routine pre-anaesthetic checkup. They will be familiarized with the use of patient-controlled analgesia (PCA) pump as well as the NRS scale(0-10) where 0 is no pain and 10 is the worst imaginable pain for postoperative analgesia. Adequate fasting will be maintained by nil per oral 8 hours for solids, 6 hours for liquids and 2 hours for clear fluids.
PRE-INDUCTION :
Intravenous access and standard ASA monitoring will be established after patients arrive at the preoperative holding area. The baseline heart rate, NIBP and SpO2 will be recorded. 1 ml of blood will be withdrawn for baseline CRP. All patients will be given 1 mcg/kg fentanyl + 0.5-1 mg midazolam before administration of the block. All patients will be positioned in the lateral position, with the side to be anesthetized being located upward. Complete aseptic precautions will be taken by wearing sterile gown and sterile gloves and sterilizing the site of the block
BLOCK PROCEDURE:
ESPB
The T9 spinous process will be located by palpation of spinous processes starting from the C7 downward,. The tip of the T9 transverse process will then be identified using a linear array high-frequency ultrasound probe that is placed in a transverse orientation. By rotation of the probe into a longitudinal orientation, a parasagittal view will be obtained visualizing the skin and subcutaneous tissue, trapezius, and erector spinae muscle layers superficial to the transverse process about 2-3 cm away from the midline. After local anesthetic infiltration, a 21-gauge 10 cm block needle will be inserted in-plane and directed craniocaudally until it contacts the T9 transverse process. Correct location of the needle tip in the fascial plane deep to the erector spinae muscle will be confirmed by injecting 1 -2 mL of saline to visualize lifting of the erector spinae muscle off the transverse process without distending the muscle and spreading caudally and cranially. Ropivacaine 0.5% at 0.4ml/kg not exceeding 30ml will then be injected into the erector spinae plane .
TMQLB
A convex array ultrasound probe (5-8 MHz) will be placed in the mid-axillary line cephalad to the iliac crest to identify the three muscles of the anterior abdominal wall (transversus abdominis, internal oblique, and external oblique). Then, the probe will be moved posteriorly to keep the transverse orientation until the aponeurosis of the transverses abdominus muscle is visible. By following this aponeurosis, QL muscle will be visualized with its attachment to the lateral edge of the transverse process of the L2 vertebral body and also visualize the thoracolumbar fascia at the lateral edge of the QL muscle. The view of the psoas major muscle anteriorly, the erector spinae muscle posteriorly, and the QL muscle adherent to the apex of the transverse process result in obtaining the Shamrock view. A 21-gauge 10 cm block needle will be inserted in-plane from the posterior to anterior direction, and the tip of the needle will be advanced through the QL muscle, penetrating the ventral proper fascia of the QL muscle. The target site for injection will be the plane between the quadratus lumborum and psoas major muscles. 1 -2 mL of saline will be used for hydrodissection for confirming the correct positioning of the needle tip. . Ropivacaine 0.5% at a dose of 0.4ml/kg not exceeding 30ml will then be injected into this plane .
ANAESTHESIA TECHNIQUE
General anaesthesia will be induced with Fentanyl(2mcg/kg) and Propofol (2mg/kg). Tracheal intubation will be facilitated by a bolus administration of Atracurium(0.5mg/kg).
Maintenance of anaesthesia will be done with Isoflurane in Air-Oxygen (FiO2- 50%) to target a MAC of 1.0. Hemodynamic parameters will be noted every 5 minutes until skin incision and thereafter every 15 minutes until the end of the procedure. Intraoperatively, inadequate analgesia will be judged by a rise in heart rate and blood pressure by 20% of baseline value which will be treated with boluses of IV fentanyl 1 µg /kg. All patients will receive Ondansetron 4 mg and Paracetamol 1 gm IV, 30 mins before the end of surgery. Reversal of neuromuscular blockade will be achieved by Neostigmine 50mcg/kg and Glycopyrrolate 10mcg/kg. Trachea will be extubated after confirmation of adequate respiratory efforts and the patient will be shifted to PACU.
POSTOPERATIVE ANALGESIA:
After shifting the patient to the PACU, a PCA pump will be connected to the IV line for all patients. It will be programmed to deliver 20 mcg boluses of Fentanyl with a lockout interval of 8 mins without baseline infusion (Maximum 4 hr limit will be set at 400 mcg). In addition, all patients will be administered IV PCM 1gm every 6hrly. If NRS >4 for 30 minutes despite the adequate use of the fentanyl IV PCA, rescue analgesia with IV morphine 3mg aliquots will be given till NRS <4.
After 24 hours ,the PCA pump will be disconnected and analgesia will be provided with IV PCM 1 gm 6hrly and IV Tramadol 50 mg 6 hrly. Blood sample for measuring the CRP levels will also be taken at this point. The patient satisfaction score and QoR-15 score will be assessed at 24 and 48 hrs after surgery.
OBSERVATIONS:
i. HR, NIBP, SaO2 at 30 mins, 1 hour, 2 hours, 4 hours, 8 hours, 12 hours and 24 hours postoperatively
ii. Postoperative pain at rest and on movement as assessed by Numeric Rating Scale at 30mins, 1 hour, 2 hours, 4 hours, 8 hours, 12 hours, and 24 hours postoperatively, where movement will be assessed by log rolling to one side.
iii. Nausea and vomiting: 3-point scale with 0- No nausea and vomiting, 1- Nausea only, 2-Vomiting. Persistent nausea or any vomiting will be treated with IV metoclopramide 10 mg and the number of episodes of vomiting will also be noted.
iv. Respiratory depression: RR < 8 or SaO2 < 90%
v. Sedation score: 4-point scale where 1- Awake, 2 - Asleep, 3 - Drowsy but arousable on verbal commands, 4 - Not arousable on verbal commands.
vi. Subjective sleep quality on the night of surgery: (NRS- 0=best sleep quality and 10=worst sleep quality)
vii. After 24 hours, the PCA device will be disconnected and patients will be shifted to the ward. Postoperative analgesia will be continued with intravenous paracetamol 1 gm 6 hourly and IV tramadol 50mg SOS.
viii. Patient satisfaction score will be assessed at 24hrs and 48hrs, where 0- highly dissatisfied, 10- highly satisfied.
ix. The QOR -15 Score will also be noted at 24 hrs and 48 hrs
x. CRP levels : Preoperatively and 24 hrs after surgery
DATA COLLECTION:
Data will be collected from the anaesthetic chart and separate proforma which are specifically made for the intraoperative and postoperative monitoring of these patients. The researcher will be blinded to the study drug patient received . All documentation relating to the study will be stored in an anonymised case report file unique to each patient.
REFERENCES
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