The interest in regional anesthesia and in particular in interfascial plane blocks has increased exponentially in the last decade .The idea of providing complete anesthesia for abdominal and thoracic surgery without using opioids and neuraxial techniques is fascinating. Until a decade ago nerve blocks and interfascial blocks were performed as landmark techniques, but the routine introduction of anesthesiology dedicated ultrasound machines in the operating theaters favored their development. Ultrasound guided regional anesthesia techniques have evolved from being used as the prerogative of locoregional anesthesia experts, to widely used in safe and well consolidated clinical practices. Consequently, many interfascial blocks are now used for providing abdominal (as for example the transversus abdominis plane block, the rectus sheath block, the quadratus lumborum block) and/or thoracic analgesia (for example pectoral nerves block, serratus block). [1,2] Adequate postoperative analgesia is of great concern. It is important for early mobilization and discharge of the patients. Regional anaesthetic techniques seems a wise and logical choice for improving acute pain management in these patients, but there are relatively few published reports in the literature. Inguinal hernioplasty utilising a mesh have become increasingly popular, having been shown to result in better patient outcomes, including fewer recurrences, a lower complication rate and a shorter hospital stay compared with open repair. However, the intensity of acute postoperative pain is attributed to the transabdominal sutures and helical tacks that are used to hold the mesh in place against the inner aspect of the abdominal wall. Transversus abdominis plane (TAP) block has become a most common method for analgesia after surgery involving the abdominal wall Various newer techniques have been proposed to enhance analgesia, either in addition to TAP block since TAP blockade is limited to somatic anesthesia of the abdominal wall and highly dependent on interfascial spread. Multimodal analgesia is used for postoperative pain in inguinal hernia repair. ESPB block is an effective regional anesthesia technique for postoperative analgesia in inguinal hernioplasty. [3] The block involves injecting an anesthetic into the plane between the erector spinae muscle and the transverse process; the drug diffuses into the paravertebral space through spaces among near by vertebrae. The drug then blocks the dorsal and ventral rami of the spinal nerves. The novel erector spinae plane (ESP) block is a simpler and safer alternative to thoracic epidural or paravertebral block. The efficacy of this technique for the management of acute and chronic pain in the thoracic region is reported. In the lumbar region, it may have the same anatomical considerations to get good results. It is an easy block to perform and is extremely versatile clinically. The learning curve usually fast and the block is easy to teach . ESPB clearly has its place in the arsenal of a well-rounded anaesthetist who may use it as part of a multimodal approach for treatment of acute and chronic pain. It is also an important component of the opioid sparing strategy. Ultimately, as it provides good levels of patient satisfaction in pain relief, the need for opioid use decreases. [4] In the vast majority of cases where ESPB is provided, patients use less opioids, are capable of doing earlier chest physiotherapy and have an overall good recovery. Given the benefits of ESPB with little risk, we foresee a single shot, or catheter-based, ESPB could become common practice. It can provide somatic and visceral analgesia and, in some cases, even anaesthesia. It has been used to cover thoraco-abdominal, spinal, upper and lower limb surgeries .The erector spinae plane block applied to the low thoracic region was also reported to provide effective analgesia in these surgeries. In this study, we aimed to compare the efficiency of transversus abdominis plane block and Erector spinae plane block on postoperative pain in patients who underwent hernioplasty under spinal anesthesia.

Prospective Randomized Control study in K.A.P.Viswanatham Govt Medical College & mahatma gandhi memorial hospital, Trichy, July 2019 To July 2020 in patients posted for elective open hernioplasty under spinal anesthesia. SAMPLE SIZE: Was determined on basis of pilot study for reduction in post operativre pain score (numerical rating scale). We calculated a minimum sample size of 24 patients was required in each group, assuming type 1 error of 0.05 and margin of error 10% . Therefore final sample selected was n = 30 in group 1 and n = 30 in group 2. N  t 2 x p (1  p) m2 Description n = required sample size t = confidence level at 95% (standard value of 1.96) p = estimated prevalence m = margin of error at 10% (standard value of 0.05) n=(1.96)2 x 0.15(1-0.15) (0.1)2 n=3.8146 x 0.1275 0.01 = 24 per group. Total of 60 patients posted for elective hernioplasty, 30 patients allotted to GROUP 1 (n = 30) and 30 patients allotted to GROUP 2 ( n =30) Inclusion Criteria: between 18-65 years, ASA 1 and 2 and BMI < 40 patients posted for elective hernia surgeries. Exclusion Criteria: patients with comorbid conditions, known allergy to local anesthetics and presence of coagulation disorder All patients were evaluated in pre-anesthetic clinic day before surgery Cardiovascular system, Respiratory system and airway examination done. Basic blood investigations was done. Patient were explained in detail regarding erector spinae block , transverse abdominis plane block their benefits, risks, Numerical rating scale and about allocation method in the ir own language . The NRS consists of a numeric version of the visual analog scale. The most common form of the NRS is a horizontal line with an eleven point numeric range. It is labeled from zero to ten, with zero being an example of someone with no pain and ten being the worst pain possible. This type of scale can be administered verbally. It can also be administered via paper to be completed physically. RANDOMISATION: was done using software Research Randomizer. The block to be performed for the patient kept in a closed envelope. All patients were kept nil per oral from 10 pm prior to day of surgery. On day of surgery patients were pre-medicated with T.Rantidine 150 mg and T. Metoclopramide 10 mg two hours before surgery with sips of water. Patient shifted to OT with closed envelope. In the OT 18 G peripheral venous cannula was inserted and intravenous fluid connected. Monitors (Mindray Imec 10) were connected and baseline values recorded. Airway trolley, emergency drugs were kept ready and anesthesia time out was done. Patient was positioned in Right lateral position , and under asepsis L3- L4 space identified and infiltrated with 2ml of 2% lignocaine, using 25 G Quincke needle subarachnoid block given with 15 mg of 0.5% hyperbaric Bupivacaine . After assuring adequate motor blockade (BROMAGE SCORE 4) and sensory block upto T 6, surgery started. At end of surgery, the closed envelope was opened by Senior anesthesiologist experienced in USG blocks and block was performed. Group 1: post-operative US guided transverse abdominis plane block with 20 ml of 0.25 % bupivacaine. Group 2: post operative US guided erector spinae plane block with 20 ml of 0.25 % bupivacaine. USG guided Transverse Abdominis Plane Block: ( Mindray Z5 And Sonoray Dus 60 ultrasound machine was used ) Patient in supine position , under asepsis 6-13 Mhz linear probe placed between iliac crest and costal margin on lateral abdominal wall in mid axillary line using sterile gel. Probe aligned, rotated and tilted in such a way to obtain clear optimized image of three muscle layers – external oblique, internal oblique, transverse abdominis. 20 G -100 mm (PAJUNK SONOPLEX NEEDLE) used. The needle inserted with in plane technique .Needle shaft identified and saline used to hydrodissect the transverse abdominis plane to visualise needle tip easier. Sterile inj bupivacaine 20 ml of 0.25 % deposited. Correct placement of drug identified by a concave shaped echoluscent deposition of anesthetic solution in plane which pushed the transverse abdominis down. US Guided Erector Spinae Plane Block :( Mindray Z 5 & Sonoray Dus 60ultrasound machine used ) Patient in lateral position , under asepsis a high frequency 6-13 Hz linear probe was placed 2.5 cm laterally on para sagittal plane to visualize the transverse process of first lumbar vertebra . 20 G -100 MM (PAJUNK SONOPLEX) needle used. Needle was directed in plane between transverse process of L1 and fascial sheath of erector spinae muscle. After hydrodissection with 2-3 ml of isotonic saline solution confirmed the correct needle tip position 20 ml of 0.25 % bupivacaine deep to erector spinae muscle. After the procedure, pain score heart rate and blood pressure noted. Patient was shifted to post-operative ward for continuous vitals monitoring and pain assessment. Patients were monitored every 15 minutes for first one hour. Numerical rating scale was used for pain assessment at 0,2,4,6,8,10 ,12 ,24 hrs post operatively . If NRS > 4 rescue analgesia inj tramadol 75 mg i.v given. The time to first rescue analgesic requirement and total dose of rescue analgesia consumption was noted. The incidence and severity of nausea and vomiting was assessed by four point categorical scale ( 0= none , 1= mild, 2= moderate and 3= severe ) . Intra venous metoclorpramide 10 mg given for severe nausea/vomiting. Any other adverse event like hypotension, dry mouth, dizziness and diplopia were recorded Statistical Analysis Data was analyzed by using SPSS version 21. The NRS score between the two sub groups was compared using student’s t-test. The statistical analysis for age, weight, duration of surgery, opioid consumption was done by unpaired t-test. Descriptive statistics was done for all data and suitable statistical tests of comparison were done. Continuous variables were analysed with the T test and categorical variables were analysed with the Chi-Square Test and Fisher Exact Test. The association between different parameters was analysed with Chi- square test. Percentage and frequencies of patients was compared using Chi- square. P-value < 0.05 is considered statistically significant. The data was entered in Microsoft Excel 2007 • Quantitative data was analyzed by students’`t test. • Qualitative data was analyzed by chi-square test.

The mean age in group TAP was 41.54 years and mean age in Group ESPB was 43.78 years. Cases and controls are not stastically significant since p-value is > 0.05 Table-1: Demographic distribution in study Age Distribution TAP % ESPB % ≤ 20 1 3.3 2 6.7 21 To 30 3 10 2 6.7 31 To 40 7 23.3 6 20 41 To 50 9 30 8 26.67 51 To 60 10 33.3 12 40 Total 30 100 30 100 Mean 41.54 43.78 SD 11.13 12.31 P-Value >0.05 Weight Distribution ≤ 50 3 10 2 6.7 51 to 60 6 20 7 23.3 61 to 70 13 43.3 14 46.7 71 to 80 7 23.3 6 20 81 to 90 1 3.3 1 3.3 Total 30 100 30 100 Mean 65.56 64.91 SD 12.59 13.13 P-Value >0.05 BMI Distribution <18.5 (Underweight) 1 3.3 1 3.3 18.5 to 24.9 (Normal Weight) 15 50 17 56.6 25 to 29.9(Overweight) 13 43.3 11 36.6 ≥30 (Obese) 1 3.3 1 3.3 <18.5 (Underweight) 1 3.3 1 3.3 Total 30 30 Mean 24.1 24.6 SD 2.14 1.84 P-Value >0.05 Height Distribution ≤ 155 2 6.6 3 10 156 To 160 5 16.6 7 23.3 161 To 165 10 33.3 11 36.7 166 To 170 12 40 7 23.3 171 To 175 1 3.3 2 6.7 Total 30 100 30 100 Mean 41.54 43.78 SD 11.13 12.31 P-Value >0.05 Physical Status Classification ASA Status 1 24 80 25 83.33 ASA Status 2 6 20 5 16.67 Total 30 100 30 100 P value >0.05 Since age, height and weight , BMI are not statistically significant, it means that there is no difference between the groups. In other words the groups contain subjects with the same basic demographic characteristics. By conventional criteria the association between the treatments groups, ASA status groups is considered to be not statistically significant since p > 0.05. Table-2: Duration of performing block in present study Duration of performing block (in minutes) TAP ESPB Mean 8.7 9.5 SD 1.2 1.7 P value >0.05 The mean time for performing block in Group TAP was 8.7 minutes versus 9.5 minutes in Group ESPB. Since p> 0.05 it is not statistically significant. Duration of performing block in present study in TAP is less in comparision with ESPB which is not statisticall significant Table-3: Postoperative pain scores (Numerical rating scale score) Time periods in hrs Mean score in TAP Mean score in ESPB P-Value 0 7(6-8) 2(1-3) 0.001* 2 5(4-6) 2(1-3) 0.05* 4 6(5-7) 3(2-4) 0.04* 6 4(3-5) 3(2-4) 0.08 8 4(3-5) 4(3-5) 0.8 10 5(4-6) 2(1-3) 0.01* 12 3(2-4) 2(1-3) 0.09 24 2(1-3) 2(1-3) 0.81 Post –operative pain score: Numerical rating scale score is statiscally significantly at 0,2,4 and 10 hrs after surgery in ESPB when compared to TAP . Table-4: The treatment groups using rescue analgesia Number of 1st dose of Inj Tramadol TAP ESPB P-Value Mean 4.9 5.1 >0.05 SD 1.8 1.9 Total Tramadol consumption in 24hrs Mean 83.4 72.5 <0.05 SD 23.3 14.4 Rescue analgesia consumption : mean total tramadol consumption in Group TAP 83.4 mg versus 72.5 mg in Group ESPB , which is statistically significant since p value < 0.05 . By conventional criteria the association between the treatment groups, the rescue analgesia using Tramadol is considered to be statistically significant since p <0.05. Table-5:Side effects in present study Side Effects TAP % ESPB % PONV 3 10.0 2 6.7 Pruritus 0 0.00 0 0.00 Leg weakness 0 0.00 0 0.00 Urinary retention 0 0.00 0 0.00 Nil 27 90 28 93.3 The incidence of PONV was 10 % in Group TAP . While the incidence of PONV in Group ESPB was 6.7 . Since P value > 0.05 it is statistically not significant. Table-6: Mean Arterial Blood pressure in present study Mean Arterial Pressure At the end of surgery After 6 hrs post OP After 12hrs post OP After 18 hrs post OP After 24 hrs post OP After 48 hrs post OP TAP Mean 97.1 94.1 96.8 93.1 96.6 97.1 SD 5.4 5.1 5.0 6.8 6.1 5.9 ESPB Mean 96.1 92.9 93.5 94.3 97.1 100.1 SD 4.7 6.4 6.5 4.9 5.5 6.9 P value Unpaired t test >0.05 >0.05 >0.05 >0.05 >0.05 >0.05 By conventional criteria the association between the treatment groups, the effect on mean arterial pressure is considered to be not statistically significant since p > 0.05. Table-7: Heart rate in present study Heart Rate At the end of surgery After 6 hrs post OP After 12hrs post OP After 18 hrs post OP After 24 hrs post OP After 48 hrs post OP TAP Mean 75 72 74 74 75 76 SD 4.0 3.9 4.1 4.4 4.5 4.9 ESPB Mean 75 73 72 74 76 78 SD 4.7 4.4 4.5 4.9 5.1 5.2 P value Unpaired t test >0.05 >0.05 >0.05 >0.05 >0.05 >0.05 By conventional criteria the association between the treatment groups,the effect on heart rate is considered to be not statistically significant since p > 0.05 Table-8: Duration of surgery Duration of Surgery TAP % ESPB % ≤ 40 minutes 2 6.6 1 3.3 41 to 50 minutes 16 53.3 11 36.7 51 to 60 minutes 10 33.3 16 53.3 ≥ 60 minutes 2 6.7 2 6.7 Mean 54.1 +5.7 60.5+6. 1 P-Value >0.05 The duration of surgery is considered to be not statistically significant since p > 0.05.

Our study demonstrated that the Erector spinae plane block is an excellent technique in reducing pain and tramadol consumption in patients scheduled for open inguinal hernioplasty. Results showed that there is significant decrease in total tramadol consumption in first 24 hrs post operatively in ESP Group [72.5 mg ± 14.4] compared to TAP Group [83.4 ± 23.3 mg] Also when comparing NRS score results showed that there is significant decrease in NRS score at 0,2,4,10 hrs post operatively in ESP group . Regarding side effects in ESP group there were two patients who suffered from nausea and vomiting while 3 persons in TAP Group experienced nausea and vomiting which is statisfically insignificant (p<0.05 ) The ESP block is a newer regional anesthetic that can provide thoracic, abdominal, and even some lower extremity analgesia. A versatile block, ESP block has been used by anesthesiologists to provide analgesia for a myriad of conditions. Much of the information on the efficacy of ESP blocking is from case reports and anecdotal experiences, so formal research is underway to compare effectiveness of TAP and ESPB in providing postoperative analgesia and post-operative analgesic consumption. Previous studies have shown ESPB to be a successful technique for postoperative analgesia with variable duration. Aman Malawat et al[5] compared ESPB and TAP block for post operative analgesia in cesarean section . There was a drastic reduction in total analgesic use over a period of 48 hrs with average of 1 doses of analgesics (diclofenac) in ESPB Group as compared to average 1 dose of analgesic requirement in TAP Group. There was a significant reduction in VAS score at rest and movement in ESP Group. Mean time to rescue alagesia in ESP block (43.54 hrs) was greater than in TAP Group (12.7hrs ).Study showed significant reduction in pain assessment with VAS score (<40 ) both at rest and movement at all time interval in ESPB Group compared to TAP Group . These findings were consistent with our study. Ahmed Hamed et al[6] assessed the efficacy of Bilateral ESPB on post operative analgesia in females undergoing abdominal hysterectomy under general anesthesia . Total fentanyl consumption in first 24 hrs was significantly lower in ESPB Group compared to control group ( 485 ±20.39 μg vs 445±67.4μg ) . VAS score was significantly lower in ESPB group . No side effect or complications noted in ESPB group. These findings were consistent with our study. Tulgar et al[7,8] evaluated the effectiveness of US guided erector spinae plane block for post operative analgesia in laproscopic cholecystectomy . NRS at rest for 20 th min, 40 min, 1 hr and 3 hrs were significantly lower in ESPB group . There was less analgesia requirement in ESPB group. One patient in ESPB Group had nausea and vomiting. Swati singh et al [9] compared analgesic effect of bilateral US guided ESPB in paediatric posted for lower abdominal surgery. Total morphine requirement in post operative period was less in ESPB Group ( 0.65±0.4 mg ) when compared to control group (1.28±0.8 mg ) . FLACC score in ESPB remained lower at 3 hrs and 6 hrs . Time of requirement of first dose of analgesia was lower in ESPB group (360 ±30 min ). Jiao Huang et al [10] did a meta-analysis to determine the clinical efficacy of US guided ESPB for post operative analgesia. It included a total of 12 RCT OF 590 patients . US guided ESPB showed reduction of i.v opiod consumption for 24 hours after surgery. Number of patients who required post operative analgesia was reduced and time for first rescue analgesia was prolonged in ESPB group. Krishna et al[11] evaluated analgesic efficacy of bilateral erector spinae block for treatment of pain after cardiac surgery in adult patients. ESPB group had higher duration of analgesia compared with control group ESPB group had reduced peri-operative total opiod usage (148.93 ± 4.9μg vs 721.98 ±18.8 μg ) KJ Chin et al[13] evaluated the analgesic efficacy of pre-operative bilateral ESPB in patients having ventral hernia repair . The highest pain score was 3.5 in ESPB for 12 hrs . There was reduction in total opiod usage in ESPB group . Santonastaso et al[14] in US guided ESPB for post operative pain control after cesarean section , found that NRS score at 0, 6, 12, 30,36 hours never exceeded 2 . No post operative nausea vomiting in ESPB groups.

Quality of post operative analgesia is better in erector spinae plane block when compared to transversus abdominis plane block for patient under going open inguinal hernioplasty under spinal anesthesia. Time taken for first rescue analgesia was longer and total analgesic dose consumption was less in ESPB group when compared to TAP.

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