The procedure of percutaneous nephrolithotomy is associated with a significant post-operative pain, which though mostly due to dilatation of the renal capsule and parenchyma, may also be due to pain along the nephrostomy tube. This requires continued efforts for improvement of analgesia because good postoperative pain control not only decreases complications but also facilitates faster recovery.

A number of studies that examined pain following PCNL surgeries concentrated on conventional approaches such as the use of opioids and nonsteroidal anti-inflammatory drugs. These medications have drawbacks and adverse effects of their own, especially in people who may have renal failure. Regional techniques provide several benefits, including the ability to treat pain near the damaged tissue area and the ability to deliver analgesia without the negative effects of opioids ^[1,2]

In numerous researches pertaining to PCNL, intercostal nerve blocks and paravertebral blocks (PVBs) have been used as peripheral nerve blocks ^[3,4].

Paravertebral block is reported to be a successful regional method for pain relief in various surgeries ^[5,6]. It can produce a unilateral, somatosensory and sympathetic block by the injection of local anesthetics into the paravertebral space containing thoracic spinal nerves and branches ^[7,8]. Compared to epidural blocks or opioids, paravertebral block offers more effective analgesia with fewer systemic side effects (such as hypotension, nausea, and vomiting) ^[9,10]. By enabling real-time view of the needle, target nerve, surrounding anatomical structures, and applied local anesthetic, ultrasound guided PVB helps to lower local anesthetic dosages and the incidence of complications (such as pneumothorax and vascular puncture), as well as failure rates.

Tramadol, a weak μ-opioid receptor agonist, blocks the absorption of serotonin and noradrenaline and is commonly used to treat postoperative pain but it may not be enough to relieve pain adequately ^[11]. In such a situation, peripheral blocks or multimodal analgesia approaches may be preferred for the management of analgesia.

Duly considering all the above facts, the present study was done to evaluate the efficacy of ultrasound guided paravertebral block for postoperative pain control in percutaneous nephrolithotomy.

AIMS AND OBJECTIVES

1.To evaluate the efficacy of ultrasound guided paravertebral block for postoperative pain control in percutaneous nephrolithotomy.

2. To assess the time for demand of first rescue analgesia and the number of requests for such analgesia.
3. To assess the changes in postoperative vital parameters, i.e. heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure and SpO2.
4. To study the side effects in relation to the drugs and procedure in use.

The present study was conducted in a prospective randomized manner on 100 patients of ASA I and II of age more than 18 years of either sex posted for elective percutaneous nephrolithotomy surgeries under general anaesthesia after taking informed consent and approval from the institutional ethics committee. Patients with history of severe cardiopulmonary, neurological, renal disease, active hepatic disease, psychiatric disorders, coagulation disorders and patients with spine deformities or cutaneous infections at the site of injection or patients with history of drug allergy were excluded from our study. A detailed history of all selected patients was taken. All relevant investigations like complete blood picture, fasting/ random blood sugar, renal function test, Chest X-ray and ECG were obtained. The entire procedure was explained to the patient and proper informed written consent was taken. A thorough pre-anaesthetic evaluation including the airway assessment and site for block assessment was done in all patients on the previous day of surgery. Patients were randomly divided into two equal groups using computer generated tables. Group P: (n=50) received USG guided paravertebral block with inj. bupivacaine 0.5% 15ml prior to surgery, after induction. Group T: (n=50) received loading dose of tramadol at 1 mg/kg intravenously 45 min before the end of the surgery. After randomization all the blocks were performed after induction of general anaesthesia by a single investigator and assessment was done by a trained staff nurse. Statistical analysis was done with the help of a statistician. The patients were explained about the entire procedure in a language of their understanding. They were also educated about the VAS score and patient’s satisfaction scale. Rescue analgesia was given to the patients who complained of pain (VAS>5/10-as per institutional protocol). Patients were kept nil orally for 8 hrs before surgery. In O.T. baseline preoperative parameters were recorded. All the patients were pre-medicated with Inj. glycopyrrolate 0.005mg/kg BW IV, Inj. midazolam 0.03mg/kg BW IV, inj. ondansetron 0.1mg/kg IV, and Inj. fentanyl 2mcg/kg body weight IV and pre-oxygenation was done with 100% oxygen for 3 minutes. Following the administration of propofol (2 mg/kg), succinylcholine (2 mg/kg), for intravenous induction, patients underwent endotracheal intubation with an appropriate tube. Anaesthesia was maintained using sevoflurane (1-2%) and a gas mixture of 50% nitrous oxide and 50% oxygen, while controlled ventilation was applied and intermittent dose of Inj. Atracurium at the dose of 0.1mg/kg body weight was used for maintenance of muscle paralysis as per requirement. Fluid resuscitation consisted of administering 0.9% sodium chloride at a rate of 5-10 mL/kg. After urinary catheterization, patients were positioned in the prone orientation Patients in Group P, before the start of surgery, underwent paravertebral block (PVB) guided by ultrasound at the T11, T12, and L1 levels, utilizing 15 ml of 0.5% bupivacaine. Under aseptic precautions, a sterile high-frequency linear probe (7.5-12 MHz) was positioned longitudinally and paramedially in the paravertebral space at the T11-L1 thoracic level defined in ultrasound as between the costo-transverse ligament, pleura, and transverse process. A 22-gauge insulated echogenic needle was then advanced vertically and caudally using an in-plane technique. During needle passage through tissues, 2-3 mL of 0.9% NaCl was administered to confirm needle tip location in the tissues anatomically. Once the needle entered the paravertebral space, 5 mL of 0.5% bupivacaine was injected at each dermatome level, with aspiration control to prevent inadvertent intravascular injection. The spread of local anesthetic was verified by anterior displacement of the pleura within the paravertebral space. Patients in Group T, received a loading dose of iv tramadol at 1 mg/kg 45 minutes before the end of the surgery. After onset of spontaneous breathing, intravenous neostigmine 0.05mg/kg body weight and glycopyrrolate 0.01mg/kg body weight was administered to antagonize the effect of muscle relaxants. Patient was extubated when the extubation criteria was fulfilled like spontaneous breathing, obeys simple commands, lift the head and hold for 30 seconds. Injection diclofenac sodium (aqua) (1 mg/kg) IV was given as rescue analgesic. Patients were moved to the post anaesthetic care facility after the surgery. The presence and severity of pain was assessed systematically in the PACU by a trained staff nurse at 0, 1, 2, 4, 8, 12, 18 and 24 hours after the procedure, using a Visual Analogue Scale (VAS). If the VAS score for the patient is >5, intravenous diclofenac at a dose of 1mg/kg was given as rescue analgesia. The time to first dose of rescue analgesic given and the total consumption of diclofenac over 24 hours were noted. Each patient was also assessed using a 5-point patient’s satisfaction scale to evaluate the level of postoperative analgesic satisfaction. Any signs of local site infection, hematoma formation, local anaesthetic toxicity due to intravascular injection of anaesthetic agents (such as dizziness, tinnitus, perioral numbness and tingling, lethargy, seizures), signs of cardiac toxicity such as atrioventricular conduction block, arrhythmias, myocardial depression, and cardiac arrest were noted. The study ended 24 hours after the surgery. STATISTICAL ANALYSIS The data collected was analysed, continuous variables were presented as Means with Standard deviation (SD) and categorical variables were presented as frequency and percentages. Student’s t-test was used for testing the significance of mean in both the groups. Qualitative data was analysed using chi-square test. All the statistical results were considered significant at the p value <0.05.

TABLE 1: POST OPERATIVE VAS SCORE AT DIFFERENT TIME INTERVALS

VAS score at different time intervals, from immediately after surgery to 24 hours after surgery were higher in Group T as compared to Group P which was statistically significant (p-value<0.05).

TABLE 2: TIME OF FIRST REQUEST TO RESCUE ANALGESIC (HOURS AFTER SURGERY).

Time of first request to rescue analgesic for Group P is (15.2±3.54) and Group T (7.5±1.93) showing that there is significant difference on comparing Group P with Group T (p value <0.05).

TABLE 3: TOTAL REQUIREMENT OF RESCUE ANALGESIC (IV DICLOFENAC IN MG) IN FIRST 24    HOURS.

Total diclofenac requirement in first 24 hrs post operatively was (16.46± 12.50) mg in Group P and (27.78± 24.94) mg in Group T. Diclofenac requirement was higher in Group T compared to Group P which was statistically significant (p value<0.05).

TABLE 4: PATIENT SATISFACTION SCORE.

              Chi square = 12.59; P = 0.006

Percentage of highly satisfied patients was 34 % and 20% in Group P and Group T respectively on patient satisfaction scale. The percentage of satisfied patients was 56 % and 40 % in Group P and Group T respectively on patient satisfaction scale. The highly dissatisfied patients were 4% (2 patients) in Group T. The difference in the patient satisfaction score between Group P and Group T was statistically significant (p value=0.006).

The procedure of percutaneous nephrolithotomy is associated with a significant post-operative pain, which though mostly due to dilatation of the renal capsule and parenchyma, may also be due to pain along the nephrostomy tube. This requires continued efforts for improvement of analgesia because good postoperative pain control not only decreases complications but also facilitates faster recovery. Tramadol, a weak μ-opioid receptor agonist, blocks the absorption of serotonin and noradrenaline and is commonly used to treat postoperative pain [15]. But it may not be enough to relieve pain adequately. In such a situation, peripheral blocks or multimodal analgesia approaches may be preferred for the management of analgesia. Paravertebral block is reported to be a successful regional method for pain relief in various surgeries. Compared to epidural blocks or opioids, paravertebral block offers more effective analgesia with fewer systemic side effects (such as hypotension, nausea, and vomiting). By enabling real- time view of the needle, target nerve, surrounding anatomical structures, and applied local anesthetic, ultrasound guided PVB helps to lower local anaesthetic dosages and the incidence of complications (such as pneumothorax and vascular puncture), as well as failure rates. In our study, the duration of analgesia was 15.2±3.54 hours in Group P, and 7.5±1.93 hours in Group T. The difference between Group P and Group T was statistically significant (p value<0.05). Our study is in accordance with- Borle et al, 2014, [3] Vijetha Devaram, et al, 2022, [12] You Zhao, et al, 2022, [13] Bharat Chandra Reddy S., et al, 2023 [14]. In our study, the total diclofenac requirement in first 24 hours post operatively was 16.46± 12.50 mg in Group P and 27.78± 24.94 mg in Group T. Diclofenac requirement was higher in group T as compared to group P which was statistically significant. (p value<0.05). Our study is in accordance with- Yayik et al, 2020,[15] Cuijuan Zheng et al, 2021, [16] Jin Wang et al,2023 [17]. In our study we found that the VAS score in first 24 hrs assessed at (0,1,2,4,8,12,18,24 hrs) postoperatively was higher in control group (Group T) compared to PVB group (Group T) and was statistically significant. The average of mean VAS score in first 24 hours was 2.4+0.66 in Group P and 3.43+0.13 in Group T and was statistically significant. (p value<0.05). Our study is in accordance with- K. Ak, et al, 2013, [4] Zehra Hatipoglu, et al, 2018, [18] Yayik et al, 2020 [15]. In our study, patients are more satisfied in group P and dissatisfaction is more in group T because ultrasound guided paravertebral block provides better and longer duration of analgesia than intravenous tramadol. Our study is in accordance with- Samy Hanoura et al, 2013,[19] Gulsah Akinci et al, 2019,[20] Vijetha Devaram, et al, 2022[12]. In our study, nausea and vomiting was noted in one patient in Group T as compared to no patients in Group P, which was statistically not significant (P value >0.05). No other side effect was noted in any of the study groups. Thus, in our study most of the observations were in accordance with the various studies conducted in the past. In our Paravertebral block was found to be very effective method for post operative analgesia. LIMITATIONS 1. Study was conducted on relatively small sample size which limit the clinical and statistical valid observation. 2. The study was conducted in single centre therefore affected by institutional practice and patient demographics. 3. Short term follow up hence focused on acute postoperative pain. 4. Postoperative pain is a subjective experience and can be difficult to quantify objectively. 5. Exclusion criteria- patients with comorbidities were excluded hence limiting the applicability of the result to comorbid populations. 6. The major limitation is dermatomal limitation of block. We did not assess block success by evaluation of dermatomal sensory loss.

From the observation and results of our study it is concluded that Paravertebral block is effective method for post operative analgesia and also improves the quality of multimodal analgesia when compared to control group, in percutaneous nephrolithotomy

1. Aydoğan H, Kucuk A, Yuce HH, Karahan MA, Ciftci H, Gulum M, Aksoy N, Yalcin S. Adding 75 mg pregabalin to analgesic regimen reduces pain scores and opioid consumption in adults following percutaneous nephrolithotomy. Revista brasileira de anestesiologia. 2014 Sep;64:335-42.
2. Parikh GP, Shah VR, Vora KS, Parikh BK, Modi MP, Panchal AR. Ultrasound guided peritubal infiltration of 0.25% ropivacaine for postoperative pain relief in percutaneous nephrolithotomy. Middle East J Anaesthesiol. 2013 Jun 1;22(2):149-54.
3. Borle AP, Chhabra A, Subramaniam R, Rewari V, Sinha R, Ramachandran R, Kumar R, Seth A. Analgesic efficacy of paravertebral bupivacaine during percutaneous nephrolithotomy: an observer blinded, randomized controlled trial. Journal of endourology. 2014 Sep 1;28(9):1085-90.
4. Ak K, Gursoy S, Duger C, Isbir AC, Kaygusuz KE, Ozdemir Kol I, Gokce GÖ, Mimaroglu
5. Thoracic paravertebral block for postoperative pain management in percutaneous nephrolithotomy patients: a randomized controlled clinical trial. Medical Principles and Practice. 2013 Dec 14;22(3):229-33.
6. Sun L, Li Q, Wang Q, Ma F, Han W, Wang M. Bilateral thoracic paravertebral block combined with general anesthesia vs. general anesthesia for patients undergoing off-pump coronary artery bypass grafting: a feasibility study. BMC anesthesiology. 2019 Dec;19:1- 7.
7. Xie PC, Zhang NN, Wu YM, Li ZF, Yang JL. Comparison between ultrasound-guided paravertebral nerve block and subarachnoid block for elderly male patients under unilateral-opened inguinal hernia repair operation: a randomised controlled trial. International Journal of Surgery. 2019 Aug 1;68:35-9.
8. Fang B, Wang Z, Huang X. Ultrasound-guided preoperative single-dose erector spinae plane block provides comparable analgesia to thoracic paravertebral block following thoracotomy: a single center randomized controlled double-blind study. Annals of translational medicine. 2019 Apr;7(8).
9. Mogahed MM, Elkahwagy MS. Paravertebral block versus intercostal nerve block in non- intubated uniportal video-assisted thoracoscopic surgery: a randomised controlled trial. Heart, Lung and Circulation. 2020 May 1;29(5):800-7.
10. Splinter WM. Somatic paravertebral block decreases opioid requirements in children undergoing appendectomy. Canadian Journal of Anesthesia. 2010 Mar 1;57(3):206.
11. Yeung JH, Gates S, Naidu BV, Wilson MJ, Smith FG. Paravertebral block versus thoracic epidural for patients undergoing thoracotomy. Cochrane Database of Systematic Reviews. 2016(2).
12. Radbruch L, Grond S, Lehmann KA. A risk-benefit assessment of tramadol in the management of pain. Drug safety. 1996 Jul;15:8-29.
13. Devaram V, Arumulla SP, Midathala J, Reddy B, Mallela S, Chaitanya K, Prasad H. Efficacy of ultrasound guided Thoracic Paravertebral block for postoperative analgesia in Patients Undergoing Percutaneous Nephrolithotomy Surgeries. Pain medicine. 2022;7(4).
14. Zhao Y, Kan Y, Huang X, Wu M, Luo W, Nie J. The efficacy and safety of paravertebral block for postoperative analgesia in renal surgery: A systematic review and meta-analysis of randomized controlled trials. Frontiers in Surgery. 2022 Jul 18;9:865362.
15. S. BCR, Tappa R, Ravula RK. Efficacy of ultrasound guided single level thoracic paravertebral block for post-operative analgesia in patients undergoing percutaneous nephrolithotomy: a randomized controlled study. Int J Res Med Sci [Internet]. 2023 Aug. 14 [cited 2024 Jul. 11];11(9):3269-72.
16. Yayik AM, Ahiskalioglu A, Demirdogen SO, Ahiskalioglu EO, Alici HA, Kursad H. Ultrasound-guided low thoracic paravertebral block versus peritubal infiltration for percutaneous nephrolithotomy: a prospective randomized study. Urolithiasis. 2020 Jun;48:235-44.
17. Zheng C, Wang J, Xie S. Ultrasound‐guided thoracic paravertebral nerve block on postoperative pain, quality of life, and recovery in patients with non‐small‐cell lung cancer. BioMed research international. 2021;2021(1):6692815.
18. Wang J, Cui X, Zhang Y, Sang X, Shen L. RETRACTED ARTICLE: The effects of intermittent bolus paravertebral block on analgesia and recovery in open hepatectomy: a randomized, double-blinded, controlled study. BMC surgery. 2023 Aug 5;23(1):218.
19. Hatipoglu Z, Gulec E, Turktan M, Izol V, Arıdogan A, Gunes Y, Ozcengiz D. Comparative study of ultrasound-guided paravertebral block versus intravenous tramadol for postoperative pain control in percutaneous nephrolithotomy. BMC anesthesiology. 2018 Dec;18:1-6.
20. Hanoura S, Elsayed M, Eldegwy M, Elsayed A, Ewieda T, Shehab M. Paravertebral block is a proper alternative anesthesia for outpatient lithotripsy. Anesthesia Essays and Researches. 2013 Sep 1;7(3):365-70.
21. Akıncı G, Hatipoğlu Z, Güleç E, Özcengiz D. Effects of ultrasound-guided thoracic paravertebral block on postoperative pain in children undergoing percutaneous nephrolithotomy. Turkish journal of anaesthesiology and reanimation. 2019 Aug;47(4):295.

1. Aydoğan H, Kucuk A, Yuce HH, Karahan MA, Ciftci H, Gulum M, Aksoy N, Yalcin S. Adding 75 mg pregabalin to analgesic regimen reduces pain scores and opioid consumption in adults following percutaneous nephrolithotomy. Revista brasileira de anestesiologia. 2014 Sep;64:335-42.
2. Parikh GP, Shah VR, Vora KS, Parikh BK, Modi MP, Panchal AR. Ultrasound guided peritubal infiltration of 0.25% ropivacaine for postoperative pain relief in percutaneous nephrolithotomy. Middle East J Anaesthesiol. 2013 Jun 1;22(2):149-54.
3. Borle AP, Chhabra A, Subramaniam R, Rewari V, Sinha R, Ramachandran R, Kumar R, Seth A. Analgesic efficacy of paravertebral bupivacaine during percutaneous nephrolithotomy: an observer blinded, randomized controlled trial. Journal of endourology. 2014 Sep 1;28(9):1085-90.
4. Ak K, Gursoy S, Duger C, Isbir AC, Kaygusuz KE, Ozdemir Kol I, Gokce GÖ, Mimaroglu
5. Thoracic paravertebral block for postoperative pain management in percutaneous nephrolithotomy patients: a randomized controlled clinical trial. Medical Principles and Practice. 2013 Dec 14;22(3):229-33.
6. Sun L, Li Q, Wang Q, Ma F, Han W, Wang M. Bilateral thoracic paravertebral block combined with general anesthesia general anesthesia for patients undergoing off-pump coronary artery bypass grafting: a feasibility study. BMC anesthesiology. 2019 Dec;19:1- 7.
7. Xie PC, Zhang NN, Wu YM, Li ZF, Yang JL. Comparison between ultrasound-guided paravertebral nerve block and subarachnoid block for elderly male patients under unilateral-opened inguinal hernia repair operation: a randomised controlled trial. International Journal of Surgery. 2019 Aug 1;68:35-9.
8. Fang B, Wang Z, Huang X. Ultrasound-guided preoperative single-dose erector spinae plane block provides comparable analgesia to thoracic paravertebral block following thoracotomy: a single center randomized controlled double-blind study. Annals of translational medicine. 2019 Apr;7(8).
9. Mogahed MM, Elkahwagy Paravertebral block versus intercostal nerve block in non- intubated uniportal video-assisted thoracoscopic surgery: a randomised controlled trial. Heart, Lung and Circulation. 2020 May 1;29(5):800-7.
10. Splinter WM. Somatic paravertebral block decreases opioid requirements in children undergoing appendectomy. Canadian Journal of Anesthesia. 2010 Mar 1;57(3):206.
11. Yeung JH, Gates S, Naidu BV, Wilson MJ, Smith Paravertebral block versus thoracic epidural for patients undergoing thoracotomy. Cochrane Database of Systematic Reviews. 2016(2).
12. Radbruch L, Grond S, Lehmann KA. A risk-benefit assessment of tramadol in the management of pain. Drug safety. 1996 Jul;15:8-29.
13. Devaram V, Arumulla SP, Midathala J, Reddy B, Mallela S, Chaitanya K, Prasad H. Efficacy of ultrasound guided Thoracic Paravertebral block for postoperative analgesia in Patients Undergoing Percutaneous Nephrolithotomy Pain medicine. 2022;7(4).
14. Zhao Y, Kan Y, Huang X, Wu M, Luo W, Nie J. The efficacy and safety of paravertebral block for postoperative analgesia in renal surgery: A systematic review and meta-analysis of randomized controlled trials. Frontiers in Surgery. 2022 Jul 18;9:865362.
15. BCR, Tappa R, Ravula RK. Efficacy of ultrasound guided single level thoracic paravertebral block for post-operative analgesia in patients undergoing percutaneous nephrolithotomy: a randomized controlled study. Int J Res Med Sci [Internet]. 2023 Aug. 14 [cited 2024 Jul. 11];11(9):3269-72.
16. Yayik AM, Ahiskalioglu A, Demirdogen SO, Ahiskalioglu EO, Alici HA, Kursad H. Ultrasound-guided low thoracic paravertebral block versus peritubal infiltration for percutaneous nephrolithotomy: a prospective randomized study. Urolithiasis. 2020 Jun;48:235-44.
17. Zheng C, Wang J, Xie S. Ultrasound‐guided thoracic paravertebral nerve block on postoperative pain, quality of life, and recovery in patients with non‐small‐cell lung BioMed research international. 2021;2021(1):6692815.
18. Wang J, Cui X, Zhang Y, Sang X, Shen L. RETRACTED ARTICLE: The effects of intermittent bolus paravertebral block on analgesia and recovery in open hepatectomy: a randomized, double-blinded, controlled study. BMC surgery. 2023 Aug 5;23(1):218.
19. Hatipoglu Z, Gulec E, Turktan M, Izol V, Arıdogan A, Gunes Y, Ozcengiz Comparative study of ultrasound-guided paravertebral block versus intravenous tramadol for postoperative pain control in percutaneous nephrolithotomy. BMC anesthesiology. 2018 Dec;18:1-6.
20. Hanoura S, Elsayed M, Eldegwy M, Elsayed A, Ewieda T, Shehab Paravertebral block is a proper alternative anesthesia for outpatient lithotripsy. Anesthesia Essays and Researches. 2013 Sep 1;7(3):365-70.
21. Akıncı G, Hatipoğlu Z, Güleç E, Özcengiz D. Effects of ultrasound-guided thoracic paravertebral block on postoperative pain in children undergoing percutaneous nephrolithotomy. Turkish journal of anaesthesiology and reanimation. 2019 Aug;47(4):295.