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Year : 2017  |  Volume : 11  |  Issue : 3  |  Page : 670-675  

Comparison of epidural analgesia with transversus abdominis plane analgesia for postoperative pain relief in patients undergoing lower abdominal surgery: A prospective randomized study

1 Department of Anesthesiology and Pain Medicine, M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India
2 Department of Anesthesiology, Manipal Hospitals, Bengaluru, Karnataka, India

Date of Web Publication23-May-2017

Correspondence Address:
Sadasivan Shankar Iyer
Department of Anesthesiology and Pain Medicine, M. S. Ramaiah Medical College and Hospitals, Bengaluru - 560 054, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0259-1162.206856

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Background: Anesthesiologists play an important role in postoperative pain management. For analgesia after lower abdominal surgery, epidural analgesia and ultrasound-guided transversus abdominis plane (TAP) block are suitable options. The study aims to compare the analgesic efficacy of both techniques. Materials and Methods: Seventy-two patients undergoing lower abdominal surgery under spinal anesthesia were randomized to postoperatively receive lumbar epidural catheter (Group E) or ultrasound-guided TAP block (Group T) through intravenous cannulas placed bilaterally. Group E received 10 ml 0.125% bupivacaine stat and 10 ml 8th hourly for 48 h. Group T received 20 ml 0.125% bupivacaine bilaterally stat and 20 ml bilaterally 8th hourly for 48 h. Pain at rest and on coughing, total paracetamol and tramadol consumption were recorded. Results: Analgesia at rest was comparable between the groups in the first 16 h. At 24 and 48 h, Group E had significantly better analgesia at rest (P = 0.001 and 0.004 respectively). Patients in Group E had significantly higher number of patients with nil or mild pain on coughing at all times. Paracetamol consumption was comparable in both groups, but tramadol consumption was significantly higher in Group T at the end of 48 h (P = 0.001). Conclusion: For lower abdominal surgeries, analgesia provided by intermittent boluses of 0.125% is comparable for first 16 h between epidural and TAP catheters. However, the quality of analgesia provided by the epidural catheter is superior to that provided by TAP catheters beyond that both at rest and on coughing with reduced opioid consumption.

Keywords: Bupivacaine, epidural analgesia, postoperative analgesia, regional anesthesia, transversus abdominis plane block

How to cite this article:
Iyer SS, Bavishi H, Mohan CV, Kaur N. Comparison of epidural analgesia with transversus abdominis plane analgesia for postoperative pain relief in patients undergoing lower abdominal surgery: A prospective randomized study. Anesth Essays Res 2017;11:670-5

How to cite this URL:
Iyer SS, Bavishi H, Mohan CV, Kaur N. Comparison of epidural analgesia with transversus abdominis plane analgesia for postoperative pain relief in patients undergoing lower abdominal surgery: A prospective randomized study. Anesth Essays Res [serial online] 2017 [cited 2020 Apr 2];11:670-5. Available from:

   Introduction Top

Control of postoperative pain is imperative for patient comfort, early mobilization, and faster recovery.[1] Good postoperative pain management has been shown to be effective in reducing perioperative morbidity associated with acute coronary events and thrombotic events in high-risk patients.[2] Opioids are the most commonly used analgesics in the perioperative period, which provide analgesia but have their own side effects. Therefore, use of a multimodal analgesic strategy is very important. Regional anesthesia and analgesia has shown to provide excellent analgesia and also provide benefits, which extend beyond the perioperative period.

For lower abdominal surgeries, epidural analgesia has been the gold standard and time-tested technique for providing postoperative analgesia, but contraindications for the same would warrant need for other equally good analgesic techniques. Rafi originally described the transversus abdominis plane (TAP) block.[3] TAP catheter-based techniques are relatively new techniques which have been used as a part of multimodal analgesia for abdominal surgery,[4] cesarean section,[5] abdominal hysterectomy,[6] and prostatectomy.[7] They are regional anesthesia techniques which provide analgesia to the skin and muscles of the anterior abdominal wall.[8] Ultrasound for guiding the TAP block was first described by Hebbard et al.[9] The advantage over neuraxial techniques is absence of hemodynamic instability, early mobilization, and not requiring prolonged urinary catheterization. Despite a low-risk of complications and a high success rate, it is an underutilized technique.[10]

Till date, only four randomized trials have been performed comparing the analgesic efficacy of epidural and TAP for abdominal surgeries, with none being able to definitively conclude the superiority of one over the other.[11] The study therefore aims to assess whether the analgesic efficacy of ultrasound-guided TAP block is comparable with epidural catheters or not for postoperative pain relief in patients undergoing lower abdominal surgery.

   Materials and Methods Top

After obtaining Institutional Ethics Committee's approval, a total of 72 patients (36 in each group) satisfying the inclusion criteria were enrolled in the study after obtaining written informed consent. The study was designed to be a prospective, randomized controlled study. The study was conducted between September 2013 and August 2015.

Inclusion criteria

  1. 18–75 years of age
  2. American Society of Anesthesiologists (ASA) Physical Status (PS) I and II
  3. Undergoing lower abdominal surgeries under spinal anesthesia.

Exclusion criteria

  1. Patient refusal for epidural or TAP catheter placement
  2. Body mass index (BMI) >30
  3. Coagulation disorders and thrombocytopenia with platelet count <150,000
  4. Infection at the site of injection and insertion of needle
  5. Use of opioids or alpha-2 agonists for sedation, premedication, or postoperative analgesia (except for tramadol).

A computer-generated random number table was used to randomize the patients in two groups (Group E and Group T). In both groups, patients were premedicated with peroral tablet ranitidine 150 mg and tablet ondansetron 8 mg. All the patients underwent lower abdominal surgery under spinal anesthesia with 2–3 ml 0.5% bupivacaine and 90 μg of buprenorphine – as per the attending anesthetist's discretion. Intraoperative sedation, if required, was provided with injection midazolam intravenously, titrated to achieve a Ramsay Sedation score of 2.

Patients in Group “E” had a lumbar epidural catheter (22-gauge, multi-orifice) placed at L1–L2 or L2–L3 (best available) intervertebral space. The catheter was placed with the patient seated, before giving the spinal anesthetic. “Loss of resistance to air” technique with 18-gauge Tuohy needle (Perifix ™, B. Braun Melsungen) was used and 5 cm of the catheter was left in situ. A test dose of 3 ml solution of 2% lidocaine with 5 μg/ml adrenaline was given to rule out intrathecal and intravascular placement of the catheter. However, the epidural catheter was not activated till at the end of the surgery. At the end of the surgery, they received 10 ml of 0.125% bupivacaine through the epidural catheter and subsequent top-ups of the same volume and concentration were given at 8th hourly intervals for 48 h.

Patients in Group “T” received bilateral ultrasound-guided TAP block at the end of the surgery. A portable ultrasound machine (GE venue 40™, GE HEALTHCARE U.S.A) with a high-frequency linear probe of 8–13 MHz was used. The ultrasonography probe was placed transversely over the anterior abdominal wall over its anterolateral aspect, across the midaxillary line, and just above the iliac crest. At this location, the three muscle layers of the anterior abdominal wall were visualized.

A 16-gauge intravenous (IV) cannula (Venflon ™, Becton and Dickinson) was advanced by the in-plane approach from the anterior direction. After placement of the cannula in between the internal oblique and the transversus abdominis muscles (TAP), 20 cc of 0.125% bupivacaine was injected and the spread of the local anesthetic (LA) solution was visualized in real time through ultrasound. After injecting the local anesthetic solution, the stylet was removed and the 16-gauge cannula was left in situ. The cannula was secured in place using waterproof “Duropore ™” plaster (3M Healthcare). Moreover, subsequent top-ups of the same volume and concentration were given at 8th hourly intervals for 48 h.

In case the patient experienced pain during the surgery, they were considered to have been dropped out of the study as an alternative technique to spinal anesthesia would have to be used. Patients in Group “E” had the epidural activated with 0.25% bupivacaine while patients in Group “T” were induced to general anesthesia.

Patients were assessed for pain at 8, 16, 24, and 48 h postoperative. Assessment of the pain was done using visual analog scale (VAS) and score noted for:

  1. Pain at rest
  2. Pain on coughing
  3. Consumption of rescue analgesia.

Postoperative pain was graded into four categories depending upon the VAS scores as:

  1. Nil = VAS score 0
  2. Mild = VAS score 1–3
  3. Moderate = VAS score 4–6
  4. Severe = VAS score >6.

IV paracetamol 1 g infusion was the first line analgesic. Paracetamol was given to patients if their VAS scores were >3/10. If the patient's pain score was >3/10 even after 1 h of IV paracetamol, then they were administered injection tramadol 50 mg as slow IV infusion and the total analgesic consumption at the end of 48 h were noted.

In addition, blood pressure, heart rate, and respiratory rate were also recorded when top-ups were given as a part of the institutional protocol.

Sample size calculation

Sample size was calculated based on the study by Vandendriessche et al.[12] Assuming similar results, it was calculated that to obtain a power of 80% within a confidence interval of 95%, a minimum of thirty patients were required in each of the two groups. Thus, a total of sixty patients were required at the least. An additional 5% (6 in each group) was taken to account for dropouts from the study.

Data analysis was done using SPSS Statistics for Windows, Version 20.0. IBM Corp., Armonk, NY.

Data were compared for demographics, VAS score at 8, 16, 24, and 48 h. Consumption of paracetamol and tramadol in the first 24 h and total analgesic consumption were also compared. Demographic data such as age, sex, ASA status, weight, height, BMI, baseline heart rate, blood pressure, and respiratory rate were compared using the Student's t-test.

Pain scores at rest and coughing at 8, 16, 24, and 48 h and paracetamol and tramadol consumption were compared using the Analysis of one-way variance (ANOVA) test.

   Results Top

Of the 72 patients selected, 69 completed the trial, of which 36 in the epidural group and 33 in the TAP block group. In two of the patients in the TAP block group, the case had to be converted to general anesthesia as the anesthesia was inadequate, while in one of the patients, the catheter became dislodged after the patient had been shifted back to the ward [Figure 1].
Figure 1: Consort flow diagram for patient enrollment, allocation and analysis

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Demographic data

Patients in both the groups were comparable with respect to age, sex, ASA-PS, weight, height, and BMI [Table 1].
Table 1: Demographic data

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Pain scores at rest

All patients were evaluated for postoperative pain at rest at 8, 16, 24, and 48 h and pain scores documented using a VAS. The pain scores were comparable in both groups at 8 and 16 h postsurgery. However, at the end of 24 and 48 h, the patients in the epidural group had significantly better analgesia when compared to TAP group (P = 0.001 and 0.004, respectively) with greater number having nil pain at rest and fewer patients reporting mild to moderate pain [Table 2].
Table 2: Pain scores at rest

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Pain scores on coughing

All patients were also evaluated for pain scores on coughing at 8, 16, 24 and 48 h using a VAS. There were significantly higher number of patients in the epidural group who had nil or mild pain compared to the number in the TAP group, (P = 0.008 and 0.001 at 16.24 and 48 h, respectively), a significant proportion of whom had mild to moderate pain [Table 3].
Table 3: Pain scores on coughing

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Postoperative analgesic consumption

IV paracetamol 1 g infusion was the first-line analgesic and IV tramadol 50 mg was the second-line analgesic. The total paracetamol consumption over 48 h was found to be comparable in both groups. However, it was found that all patients in the TAP group eventually required paracetamol while 5 out of the 36 patients in the epidural group did not need any rescue analgesia at all. Overall requirements of tramadol were significantly lower in the epidural group than in the TAP block group (P = 0.001), with very few patients in the epidural group even requiring tramadol [Table 4] and [Table 5].
Table 4: Comparison of paracetamol comparison

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Table 5: Comparison of tramadol consumption

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   Discussion Top

As our understanding of pain and the pathophysiology of the postoperative period has improved, the importance of adequate management of postoperative pain is increasingly being appreciated, to avoid respiratory and cardiovascular complication that can arise due to inadequate analgesia. This has led to an increase in the use of regional anesthesia techniques for postoperative pain relief.

For analgesia following lower abdominal surgeries, a variety of pain relief techniques can be used as epidural analgesia, TAP block, and infiltration of LA at the site of incision and quadratus lumborum block. Epidural anesthesia considered as the “gold standard” has been established to provide excellent analgesia as well as attenuation of neurogenic contribution to inflammation. However, it can cause hemodynamic disturbances with concerns of epidural catheter placement and removal in patients on anticoagulants therapy.

The TAP block provides reliable somatic analgesia lower abdominal incision surgeries. Use of ultrasound helps in correct localization of the plane and accurate placement of the needle and catheter. Surgeries for which TAP block have been used as part of multimodal analgesia includes cesarean section, total abdominal hysterectomy open inguinal hernia, renal transplant, open appendectomies, and open prostatectomy. Supporters of the technique claim superior analgesia compared to that provided by systemic opioids.[6],[13]

Belavy et al. reported significantly better analgesia and reduced 24 h morphine consumption in patients who received ultrasound-guided TAP block, following cesarean section under spinal anesthesia compared to those who underwent cesarean section under spinal anesthesia but did not receive TAP block.[14] In another study, Baaj et al. randomized 40 women to receive either local anesthetic (n = 20) or saline (n = 20) TAP blocks in addition to a plain bupivacaine spinal block for elective cesarean section.[15] A significant reduction in 24-h morphine requirement was observed in the local anesthetic TAP block group versus controls (26 mg ± 5 mg vs. 63 mg ± 5 mg; P < 0.05). The authors report lower postoperative nausea and vomiting PONV, lower 24-h VAS scores, and higher satisfaction in the local anesthetic TAP block group, but no statistical measures were reported.

Lower abdominal surgeries were chosen because the TAP block is known to anesthetize 9th to 12th thoracic nerves along their course in the anterior abdominal wall. This would be adequate for analgesia for infra-umbilical abdominal surgeries. To avoid the confounding effect of bilateral effect of epidural analgesia, surgeries with bilateral incisions, midline incisions or incisions crossing the midline were chosen and bilateral TAP block was used in the comparison. In our study we used an IV cannula placed in the TAP plane bilaterally under ultrasound guidance with top-ups of 0.125% bupivacaine given every 8th hourly for 48 h.

A study performed by Vandendriessche, et al. compared bilateral transverses abdominis catheter infusion of levobupivacaine against epidural infusion with levobupivacaine with sufentanil.[12] On the basis of VAS scores at rest and on coughing, they concluded that the quality of analgesia was comparable in the two groups with VAS score at rest 15 ± 12 in the TAP block vs. 4 ± 8 in the epidural group while the VAS scores on coughing were 48 ± 18 and 32 ± 21, respectively. Our results show better analgesia at rest (after first 16 h) and on coughing (throughout the postoperative period) in the epidural group.

Rao et al. studied the analgesic efficacy of continuous epidural analgesia with continuous TAP block for major abdominal surgery.[16] The authors found no differences in regard to pain scores at any point or over time, postoperative fentanyl requirement, and patient satisfaction. In contrast to results of Rao et al., we found analgesia comparable between the groups only till the first 16 h beyond which the patients in the epidural group reported better VAS scores both at rest and during coughing In our study, paracetamol requirement in both groups were comparable; however, the epidural group had larger number of patients needing nil or lower doses of paracetamol. Tramadol (used as the second line analgesic) requirement however was significantly higher in the TAP block group at the end of 48 h. We found that 94.4% of the patients in the epidural group did not need tramadol in their postoperative period whereas only 60% of the patients in the TAP group did not need tramadol. Three percent of patients in the TAP group required up to 100 mg of tramadol at the end of 48 h compared to none in the epidural group. This was contrasting to the results of Rao et al.

In another study done by Kandi, evaluating the efficacy of ultrasound-guided TAP block versus epidural analgesia in pain management following lower abdominal surgery,[17] the author has reported that TAP block provided highly effective postoperative analgesia in the first 24 h with longer analgesic free periods in the TAP group compared to the epidural group during the first 24 h postsurgery. There was also a significant reduction in the number of cases needing more than 200 μg/kg of morphine in the TAP group when compared to the epidural group.

Kanazi et al. compared subarachnoid morphine with TAP block in postcesarean section pain.[18] They primarily evaluated the time to first request for analgesia while secondarily they looked at consumption of tramadol (rescue analgesia) in first 12 h. The results favored intrathecal morphine wherein median (range) time to first request for analgesic was 8 (2–36) h compared to 4 (0.5–29) h in the TAP group (P = 0.005). Even the tramadol consumption was shown to be significantly lower in the subarachnoid morphine group (0–1 vs. 0–2, P = 0.03).

Niraj et al. compared the analgesic efficacy of a four-quadrant TAP block and continuous posterior TAP analgesia with epidural analgesia in patients undergoing laparoscopic colorectal surgery.[19] The authors report a significantly higher consumption of the rescue analgesic tramadol in the TAP group (400 mg) than in the epidural group (200 mg) (P = 0.002), similar to the results of our study. The authors also report comparable pain scores between patients in the two groups with comparable incidence of PONV.

None of the patients in our study in either group had any complications arising from the regional technique. Both groups of patients were hemodynamically stable during the 48 h of follow-up.

The epidural catheter was placed at the time of administering the spinal anesthetic for convenience. The TAP block cannulas were placed after the surgery to avoid them from posing a hindrance in the operative field. To compensate for the discrepancy in the timing of administration of the actual drug, the epidural administration of the drug was also done in the postoperative period.

The decision to give intermittent boluses of local anesthetic over continuous infusions was taken due to the issue of cost constraints raised by the Ethics Committee. Based on the same concerns of cost, commercially available regional anesthesia catheters were eschewed in favor of 16-gauge cannulas for performance of the TAP blocks. This may be viewed as a possible drawback of our study. Another limitation is that postoperative top-ups in the TAP group were given without real-time visualization using ultrasound and thus the drug spread could not be seen and possible catheter dislodgement, resulting in higher pain scores could not be ruled out.

   Conclusion Top

Analgesia for lower abdominal surgeries provided by intermittent boluses of 0.125% bupivacaine was comparable when provided by either the epidural catheter or the TAP catheters, albeit only for a short postoperative course beyond which the epidural analgesia is superior to that provided by TAP block with reduced analgesic consumption and no incidence of hemodynamic disturbances. However, due to the limited number of studies evaluating the analgesic efficacy of the two techniques, more randomized trials need to be performed to reach any definite conclusion.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Yeager MP, Glass DD, Neff RK, Brinck-Johnsen T. Epidural anesthesia and analgesia in high-risk surgical patients. Anesthesiology 1987;66:729-36.  Back to cited text no. 1
Tuman KJ, McCarthy RJ, March RJ, DeLaria GA, Patel RV, Ivankovich AD. Effects of epidural anesthesia and analgesia on coagulation and outcome after major vascular surgery. Anesth Analg 1991;73:696-704.  Back to cited text no. 2
Rafi AN. Abdominal field block: A new approach via the lumbar triangle. Anaesthesia 2001;56:1024-6.  Back to cited text no. 3
McDonnell JG, O'Donnell B, Curley G, Heffernan A, Power C, Laffey JG. The analgesic efficacy of transversus abdominis plane block after abdominal surgery: A prospective randomized controlled trial. Anesth Analg 2007;104:193-7.  Back to cited text no. 4
Abdallah FW, Halpern SH, Margarido CB. Transversus abdominis plane block for postoperative analgesia after caesarean delivery performed under spinal anaesthesia? A systematic review and meta-analysis. Br J Anaesth 2012;109:679-87.  Back to cited text no. 5
Carney J, McDonnell JG, Ochana A, Bhinder R, Laffey JG. The transversus abdominis plane block provides effective postoperative analgesia in patients undergoing total abdominal hysterectomy. Anesth Analg 2008;107:2056-60.  Back to cited text no. 6
O'Donnell BD, McDonnell JG, McShane AJ. The transversus abdominis plane (TAP) block in open retropubic prostatectomy. Reg Anesth Pain Med 2006;31:91.  Back to cited text no. 7
Charlton S, Cyna AM, Middleton P, Griffiths JD. Perioperative transversus abdominis plane (TAP) blocks for analgesia after abdominal surgery. Cochrane Database Syst Rev 2010;(12):CD007705. doi: 10.1002/14651858.   Back to cited text no. 8
Hebbard P, Fujiwara Y, Shibata Y, Royse C. Ultrasound-guided transversus abdominis plane (TAP) block. Anaesth Intensive Care 2007;35:616-7.  Back to cited text no. 9
Kearns RJ, Young SJ. Transversus abdominis plane blocks; a national survey of techniques used by UK obstetric anaesthetists. Int J Obstet Anesth 2011;20:103-4.  Back to cited text no. 10
Zhang P, Deng XQ, Zhang R, Zhu T. Comparison of transversus abdominis plane block and epidural analgesia for pain relief after surgery. Br J Anaesth 2015;114:339.  Back to cited text no. 11
Vandendriessche H, Hoydonckx Y, Pexsters A. Transversus abdomonis plane block (TAP) versus patient controlled epidural analgesia (PCEA) to treat post-cesarean section pain: A randomized, double-blind trial. Acta Anaesthsiol Belg 2010;61:107.  Back to cited text no. 12
Tan TT, Teoh WH, Woo DC, Ocampo CE, Shah MK, Sia AT. A randomised trial of the analgesic efficacy of ultrasound-guided transversus abdominis plane block after caesarean delivery under general anaesthesia. Eur J Anaesthesiol 2012;29:88-94.  Back to cited text no. 13
Belavy D, Cowlishaw PJ, Howes M, Phillips F. Ultrasound-guided transversus abdominis plane block for analgesia after caesarean delivery. Br J Anaesth 2009;103:726-30.  Back to cited text no. 14
Baaj JM, Alsatli RA, Majaj HA, Babay ZA, Thallaj AK. Efficacy of ultrasound-guided transversus abdominis plane (TAP) block for postcesarean section delivery analgesia – A double-blind, placebo-controlled, randomized study. Middle East J Anaesthesiol 2010;20:821-6.  Back to cited text no. 15
Rao Kadam V, Van Wijk RM, Moran JI, Miller D. Epidural versus continuous transversus abdominis plane catheter technique for postoperative analgesia after abdominal surgery. Anaesth Intensive Care 2013;41:476-81.  Back to cited text no. 16
Kandi Y. Efficcy of ultrasound guided transversus abdominis plane block versus epidural analgesia in pain management following lower abdominal surgery. Ain Shams J Anesthesiol 2015;8:653-7.  Back to cited text no. 17
Kanazi GE, Aouad MT, Abdallah FW, Khatib MI, Adham AM, Harfoush DW, et al. The analgesic efficacy of subarachnoid morphine in comparison with ultrasound-guided transversus abdominis plane block after cesarean delivery: A randomized controlled trial. Anesth Analg 2010;111:475-81.  Back to cited text no. 18
Niraj G, Kelkar A, Jeyapalan I, Graff-Baker P, Williams O, Darbar A, et al. Comparison of analgesic efficacy of subcostal transversus abdominis plane blocks with epidural analgesia following upper abdominal surgery. Anaesthesia 2011;66:465-71.  Back to cited text no. 19


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]

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