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Quadratus lumborum block for patients undergoing percutaneous nephrolithotomy: A randomized controlled study

 Department of Anesthesiology, King George's Medical University, Lucknow, Uttar Pradesh, India

Date of Submission02-Jul-2021
Date of Acceptance31-Jul-2021
Date of Web Publication07-Nov-2021

Correspondence Address:
Rati Prabha,
Department of Anesthesiology, King George's Medical University, Lucknow, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aer.aer_92_21


Background: Recent studies have supported the use of quadratus lumborum block (QLB) for postoperative analgesia for patients undergoing renal surgery. Aims: The aim was to study the efficacy of posterior QLB for postoperative analgesia in patients undergoing percutaneous nephrolithotomy (PCNL). Settings and Design: This trial was a hospital-based, randomized, double-blind, controlled, prospective study. Materials and Methods: Forty patients aged from 18 to 60 years, belonging to the American Society of Anesthesiologists physical status I–III and scheduled for unilateral PCNL under spinal anesthesia were administered ultrasound-guided posterior QLB with 30 ml of either 0.2% ropivacaine (Group Q) or normal saline (Group C) after the subarachnoid block. Duration of analgesia was the primary outcome variable. Statistical Analysis Used: Data were compiled in Microsoft Excel, and analyses were performed in SPSS (version; IBM, Armonk, New York, USA). Unpaired t-test, Mann–Whitney U test, and Fisher's exact test were used for the comparison of continuous, ordinal, and categorical data, respectively. Results: Duration of analgesia was significantly longer in Group Q (1167.10 ± 89.74 vs. 290.25 ± 47.38 min), as compared to Group C. Except at the end of the surgery, visual analog scale at rest and on movement was significantly lower till 20th h in Group Q. Patient satisfaction was better, and analgesic consumption was lower in Group Q. Side effects were similar in both groups. Conclusions: QLB provides good quality, and prolonged duration of postoperative analgesia compared to placebo for PCNL, but more large-scale studies are needed to recommend it for routine use.

Keywords: Nerve block, postsurgical pain, quadratus lumborum block, regional anesthesia

How to cite this URL:
Raman R, Prabha R. Quadratus lumborum block for patients undergoing percutaneous nephrolithotomy: A randomized controlled study. Anesth Essays Res [Epub ahead of print] [cited 2022 Jul 1]. Available from:

   Introduction Top

Quadratus lumborum block (QLB) is a relatively new regional analgesic technique for pain relief after abdominal surgery. It has been used for providing postoperative analgesia for patients after several types of abdominal surgeries including various renal surgeries.[1],[2],[3],[4],[5],[6] It blocks somatic nerve fibers supplying the abdominal wall and has the potential to block the sympathetic nerve supply of the abdomen.[7] As QLB is effective in providing analgesia after renal surgeries, we hypothesized that posterior QLB should be effective in providing adequate postoperative pain relief to patients undergoing percutaneous nephrolithotomy (PCNL) and devised the present trial to test this hypothesis.

   Materials and Methods Top

This prospective, randomized, double-blind, and controlled study was conducted after approval of the institute's ethics committee (Name of IRB: Institutional Ethics Committee, reference number: 78th ECM II A/P7, date: June 23rd 2016). Written and informed consent from patients was obtained for participation in the study and the use of the patient data for research and educational purposes. The trial followed the guidelines laid down in the Declaration of Helsinki (2013). The present study was registered prospectively with Clinical Trials Registry-India (registration number: CTRI/2017/04/008300). The American Society of Anesthesiologists physical status I-III patients belonging to the age group of 18–60 years of either sex scheduled for the elective unilateral percutaneous nephrolithotomy under spinal anesthesia were recruited for the study. Exclusion criteria were refusal to give consent, allergy to study drugs, chronic analgesic use, infection at the site of block, and patients taking anticoagulants or having coagulopathy.

Patients were divided into two groups: Group Q (received QLB) and Group C (control). After applying standard anesthesia monitors (pulse oximeter, electrocardiogram, and noninvasive blood pressure) and securing intravenous access, patients were preloaded with 15 −1 lactated ringer's solution. Spinal anesthesia was administered at L3–L4 intervertebral space (or at L2–L3 intervertebral space if it was not possible at L3–L4) using 15 mg of 0.5% hyperbaric bupivacaine and 25 μg fentanyl with a 25G, pencil-point spinal needle. After the confirmation of the spinal anesthesia up to T6 sensory dermatome level, posterior QLB (also known as Type II QLB) was administered. For this, the participants were placed in a lateral position with the side to be blocked positioned up. Aseptic precautions were obtained for the procedure. A low-frequency ultrasound probe was placed transversely between the iliac crest and costal margin in the anterior axillary line to visualize the three muscles of the anterolateral abdominal wall (internal oblique, external oblique, and transversus abdominis). The three abdominal muscles were then followed laterally to visualize aponeurosis of transversus abdominis, quadratus lumborum, latissimus dorsi, and part of erector spinae muscles. A 10cm, 21G block needle was inserted with in-plane approach from posterior to anterior direction to place the needle tip posterior to the quadratus lumborum muscle. One milliliter of the normal saline was injected, and the spread was observed between the posterior surface of quadratus lumborum muscle and the medial layer of the thoracolumbar fascia (TLF). After the confirmation of the correct needle tip position and saline spread, the drug solution was injected. Group Q patients were given the block using 30 mL 0.2% ropivacaine, whereas the patients of Group C receive the same block using 30 mL of normal saline. Randomization was done using computer-generated random numbers. Allocation concealment was done using opaque-sealed envelope technique. Drug solutions were prepared in the identical syringes without informing anyone about group allocation by an anesthesia technician who opened the sealed envelopes containing the group of the patients. The anesthesia technician did not take any further part in the study. Patients and anesthetist administering the block and recording the data were unaware of the study group allocation. All blocks were administered by consultant anesthesiologists having experience of at least 2 years for the block technique. After the block, patients were repositioned, and surgery was allowed to proceed. No other analgesic or sedative drug was given to the study participants unless they complained of pain or anxiety in the intraoperative period.

Postoperative analgesia was assessed at the end of surgery and then every 2 h using a 10 cm visual analog scale (VAS) at rest and on movement. Patients requesting pain relief or complaining of pain intensity >4 on VAS were given an intravenous infusion of paracetamol 15 −1 (up to 1000 mg per dose) for analgesia (maximum cumulative dose 4000 mg in 24 h). If pain was not relieved by a single dose of paracetamol, intravenous injection of 2 −1 tramadol (maximum 100 mg per dose) was given along with injection ondansetron. The time duration between administering QLB and rescue analgesia was recorded as the duration of analgesia. Further analgesia was provided with intravenous paracetamol, and if needed with injection tramadol, limited by the maximum daily doses. Total paracetamol and tramadol consumed in the first 24 h after the end of surgery were recorded. Adverse effects including but not limited to direct needle trauma to abdominal viscera, bleeding, prolonged muscle weakness, and hemodynamic instability were recorded. Perioperative patient satisfaction was assessed on the second postoperative day using 5-point Likert scale: 1 = very dissatisfied, 2 = dissatisfied, 3 = slightly dissatisfied, 4 = quite satisfied, and 5 = completely satisfied.[8]

The primary outcome variable of the present trial was the duration of analgesia. The secondary outcome variables were intensity of postoperative pain on the movement and at rest measured using VAS, postoperative analgesic consumption, patient satisfaction, and side effects.

Statistical analysis

A sample size of 17 patients per group was required (α =0.05; power = 0.80) to detect a difference of 30 min with a standard deviation of 30 min in the duration of analgesia. The present study had a sample size of 20 patients in each group to compensate for data and/or participant loss. Comparison of two groups of numeric data having normal distribution was done using unpaired t-test (for age, weight, height, body mass index, duration of surgery, duration of analgesia, and duration of analgesics). Ordinal variables were compared using Mann–Whitney U test (for patient satisfaction and ASA physical status). Categorical data were analyzed using Fisher's exact test (for gender and side effects). A two-sided P < 0.05 was considered statistically significant. Data were compiled in Microsoft Excel, and analyses were performed using the Statistical Package for the Social Sciences (Windows version 22.0).

   Results Top

The flow of patients in our study as per the CONSORT guidelines is shown in [Figure 1]. As shown in [Table 1], no statistical difference in baseline and demographic data was observed. None of the patients was given intraoperative analgesic or sedative. Characteristics of postoperative analgesia and patient satisfaction are compared in [Table 2]. Duration of analgesia was statistically longer in Group Q as compared to Group C. Pain intensity in the postoperative period is compared in [Figure 2] and [Figure 3]. Pain intensity on VAS at rest and on the movement was statistically lower in Group Q till the 20th postoperative hour, except immediately at end of the surgery. The VAS scores were statistically similar between the groups at end of surgery, at 22nd h and at 24th h. Total analgesic consumption of both paracetamol and tramadol was higher in Group C. Patient satisfaction score was 1, 2, 3, 4, and 5 in 0 (0.00%), 1 (5.00%), 3 (15.00%), 5 (25.00%), and 11 (55.00%) patients, respectively, in Group Q. The same scores were observed in 8 (40.00%), 5 (25.00%), 3 (15.00%), 2 (10.00%), and two patients in Group C, respectively. Patient satisfaction score was statistically higher in Group Q compared to Group C. Three (15.00%) patients in Group C and one (5.00%) patient in Group Q had vomiting. The difference was not statistically significant with P value of 0.605.
Figure 1: Participant flow in the trial as per CONSORT guidelines

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Table 1: Demographic and baseline data

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Table 2: Analgesic characteristics and patient satisfaction

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Figure 2: Postoperative pain intensity rest

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Figure 3: Postoperative pain intensity on movement

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   Discussion Top

In this trial, we studied the analgesic effects of QLB on postoperative pain in patients undergoing PCNL and compared it with placebo. We observed that the duration of analgesia in patients receiving QLB was significantly more than the control. Pain relief was better in the postoperative period with lower pain scores in the first 20 h, except at the immediate end of surgery. The analgesic consumed was lower in first the 24 h in patients receiving QLB. Patient satisfaction was better, whereas the side effects were similar.

QLB, first described by Blanco et al., was a derivative of transversus abdominis plane (TAP) block.[1] There are four subtypes of QLB which are named according to the location of local anesthetic delivery in relation to quadratus lumborum muscle-lateral QLB, posterior QLB, anterior QLB, and intramuscular QLB.[9] The initial QLB, now commonly termed as QLB Type 1 or lateral QLB, is rarely used by even the original authors. In posterior QLB, which was studied in our trial, the local anesthetic is deposited between the posterior surface of quadratus lumborum muscle and the medial lamina of TLF. Similarly, other interfascial blocks, the posterior QLB has a variable spread of drug solution.[10] It consistently spreads to TAP, around quadratus lumborum muscle, and along the middle lamina of TLF.[11],[12] The TLF contains a dense network of sympathetic nerve fibers of the abdomen. Blockade of these nerve fibers provides relief from sympathetic-mediated pain.[9],[13],[14] In addition, the injected drug may also spread cranially to the lumbar paravertebral space along TLF and endothoracic fascia.[13],[14] These may be responsible for the additional visceral and somatic block with wider width of analgesia (T7 to L4 dermatome) observed in posterior QLB as compared to the more traditional TAP block.[15],[16],[17]

Our findings of better postoperative analgesia in terms of the longer time to first analgesic request, lower VAS scores, and lower requirement of postoperative analgesia by posterior QLB are supported by previous studies. Okmen et al. compared the posterior QLB with placebo in 60 patients after laparoscopic cholecystectomy.[18] They observed that postoperative VAS was lower at all time points of observation till 24 h in patients receiving the QLB. There was a reduction in postoperative tramadol use. Duration of analgesia was not studied in their study. Blanco et al. compared the postoperative analgesic effect of posterior QLB with placebo in fifty patients after lower segment cesarean section.[1] They observed that VAS was reduced at all time points until 24 h. Morphine consumption was reduced at 6th and 12th postoperative hours but not beyond that. Other authors have compared the posterior QLB with TAP block and have reported either similar or better analgesia than the TAP block for postoperative analgesia.[3],[4],[19],[20]

The reported duration of analgesia by QLB varies widely, but a recent meta-analysis observed that the duration of analgesia is up to 24 h.[2] This agrees with our observation of better analgesia till the 20th h after the end of surgery in patients receiving QLB. A significant difference in VAS immediately after the end of the surgery was not observed in the current study, possibly due to the analgesic effect of spinal anesthesia in both groups.

Patient satisfaction was better in patients' posterior QLB group in the present study. Better postoperative analgesia may be the reason for this observation. We could not find any study comparing the effect of posterior QLB with placebo for patient satisfaction. Baytar et al. observed similar postoperative satisfaction scores when they compared the posterior QLB with TAP block in patients undergoing laparoscopic cholecystectomy.[4] In their study, the postoperative pain was similar between the two groups.

As observed in the current study trial, side effects due to posterior QLB appear to be uncommon. In sixty posterior quadratus lumborum blocks (QLBs), Verma et al. did not find any side effects.[3] Sa et al. reported serious hypotension and tachycardia in two patients after the posterior QLB due to blockade of sympathetic fibers in TLF and the paravertebral space.[21] Transient sensory and motor loss of lower limbs have been reported due to blockade of lumbar nerve roots.[22]

One of the limitations of our study was that we did not record the dermatomal distribution of analgesia in our patients. Another limitation is that the sample size was not large enough to detect the difference in the side effects and other secondary outcome variables.

   Conclusion Top

We found that QLB provides good analgesia after PCNL surgery. However, further studies are needed before recommending its routine clinical use.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Blanco R, Ansari T, Girgis E. Quadratus lumborum block for postoperative pain after caesarean section: A randomised controlled trial. Eur J Anaesthesiol 2015;32:812-8.  Back to cited text no. 1
Jin Z, Liu J, Li R, Gan TJ, He Y, Lin J. Single injection quadratus lumborum block for postoperative analgesia in adult surgical population: A systematic review and meta-analysis. J Clin Anesth 2020;62:109715.  Back to cited text no. 2
Verma K, Malawat A, Jethava D, Jethava DD. Comparison of transversus abdominis plane block and quadratus lumborum block for post-caesarean section analgesia: A randomised clinical trial. Indian J Anaesth 2019;63:820-6.  Back to cited text no. 3
[PUBMED]  [Full text]  
Baytar Ç, Yılmaz C, Karasu D, Topal S. Comparison of ultrasound-guided subcostal transversus abdominis plane block and quadratus lumborum block in laparoscopic cholecystectomy: A prospective, randomized, controlled clinical study. Pain Res Manag 2019;2019:2815301.  Back to cited text no. 4
Cardoso JM, Sá M, Reis H, Almeida L, Sampaio JC, Pinheiro C, et al. Type II Quadratus Lumborum block for a sub-total gastrectomy in a septic patient. Braz J Anesthesiol 2018;68:186-9.  Back to cited text no. 5
Li X, Xu ZZ, Li YT, Lin ZM, Liu ZY, Wang D×. Analgesic efficacy of two approaches of ultrasound-guided quadratus lumborum block for laparoscopic renal surgery: A randomised controlled trial. Eur J Anaesthesiol 2021;38:265-74.  Back to cited text no. 6
Akerman M, Pejčić N, Veličković I. A review of the quadratus lumborum block and ERAS. Front Med (Lausanne) 2018;5:44.  Back to cited text no. 7
Xu J, Yang X, Hu X, Chen X, Zhang J, Wang Y. Multilevel thoracic paravertebral block using ropivacaine with/without dexmedetomidine in video-assisted thoracoscopic surgery. J Cardiothorac Vasc Anesth 2018;32:318-24.  Back to cited text no. 8
Elsharkawy H, El-Boghdadly K, Barrington M. Quadratus lumborum block: Anatomical concepts, mechanisms, and techniques. Anesthesiology 2019;130:322-35.  Back to cited text no. 9
Gupta A, Sondekoppam R, Kalagara H. Quadratus lumborum block: A technical review. Curr Anesthesiol Rep 2019;9:257-62.  Back to cited text no. 10
Carline L, McLeod GA, Lamb C. A cadaver study comparing spread of dye and nerve involvement after three different quadratus lumborum blocks. Br J Anaesth 2016;117:387-94.  Back to cited text no. 11
Blanco R. The mechanism of the quadratus lumborum block: A peripheral sympathetic field block? Br J Anaesth 2016;11:117.  Back to cited text no. 12
Elsharkawy H, El-Boghdadly K, Kolli S, Esa WAS, DeGrande S, Soliman LM, et al. Injectate spread following anterior sub-costal and posterior approaches to the quadratus lumborum block: A comparative cadaveric study. Eur J Anaesthesiol 2017;34:587-95.  Back to cited text no. 13
Tamura T, Kitamura K, Yokota S, Ito S, Shibata Y, Nishiwaki K. Spread of Quadratus Lumborum Block to the Paravertebral Space Via Intramuscular Injection: A Volunteer Study. Reg Anesth Pain Med 2018;43:372-7.  Back to cited text no. 14
Ueshima H, Otake H, Lin JA. Ultrasound-guided quadratus lumborum block: An updated review of anatomy and techniques. Biomed Res Int 2017;2017:2752876.  Back to cited text no. 15
Sharkey A, Finnerty O, Mc Donnell JG. Transversus abdominis plane block. Curr Anesthesiol Rep 2013;3:223-9.  Back to cited text no. 16
Carney J, Finnerty O, Rauf J, Bergin D, Laffey JG, Mc Donnell JG. Studies on the spread of local anaesthetic solution in transversus abdominis plane blocks. Anaesthesia 2011;66:1023-30.  Back to cited text no. 17
Ökmen K, Metin Ökmen B, Topal S. Ultrasound-guided posterior quadratus lumborum block for postoperative pain after laparoscopic cholecystectomy: A randomized controlled double blind study. J Clin Anesth 2018;49:112-7.  Back to cited text no. 18
Yousef NK. Quadratus lumborum block versus transversus abdominis plane block in patients undergoing total abdominal hysterectomy: A randomized prospective controlled trial. Anesth Essays Res 2018;12:742-7.  Back to cited text no. 19
[PUBMED]  [Full text]  
Blanco R, Ansari T, Riad W, Shetty N. Quadratus lumborum block versus transversus abdominis plane block for postoperative pain after cesarean delivery: A randomized controlled trial. Reg Anesth Pain Med 2016;41:757-62.  Back to cited text no. 20
Sá M, Cardoso JM, Reis H, Esteves M, Sampaio J, Gouveia I, et al. Quadratus lumborum block: Are we aware of its side effects? A report of 2 cases. Braz J Anesthesiol 2018;68:396-9.  Back to cited text no. 21
Fujimoto H, Irie T, Mihara T, Mizuno Y, Nomura T, Goto T. Effect of posterior quadratus lumborum blockade on the quality of recovery after major gynaecological laparoscopic surgery: A randomized controlled trial. Anaesth Intensive Care 2019;47:146-51.  Back to cited text no. 22


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]


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