• Users Online: 730
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
Year : 2019  |  Volume : 6  |  Issue : 2  |  Page : 243-248

Ultrasound-guided transversus abdominis plane block for total abdominal hysterectomy: comparison between magnesium sulfate and dexamethasone as adjuvants

1 Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Mansoura University, Mansoura, Egypt
2 Department of Obstetrics and Gynecology, Faculty of Medicine, Mansoura University, Egypt
3 Department of Surgical Oncology, Oncology Center, Mansoura University, Mansoura, Egypt

Date of Submission03-Mar-2019
Date of Acceptance04-Mar-2019
Date of Web Publication12-Jun-2019

Correspondence Address:
Mona Gad
Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Mansoura University
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/roaic.roaic_24_19

Rights and Permissions

Background Patients undergoing total abdominal hysterectomy (TAH) experience severe pain postoperatively, requiring a multimodal approach to analgesia. The transversus abdominis plane (TAP) block seems to be an ideal approach. This block may be achieved using bupivacaine with adjuvants such as dexamethasone or magnesium sulfate, which were compared in this study.
Patient and methods A total of 60 patients subjected to TAH were randomly allocated to receive TAP block using 18 ml 0.25% bupivacaine (45 mg) with 2 ml (200 mg) of magnesium sulfate on either side in group M (n=30), whereas patients in group D (n=30) received 18 ml 0.25% bupivacaine (45 mg) with 2 ml (8 mg) of dexamethasone on either side. The visual analog score was considered as the primary outcome, whereas the secondary outcomes were included time to first analgesic request, the total postoperative opioid consumption, nausea and vomiting score, and patient’s satisfaction.
Results Visual analog scores showed significantly higher values at 8 and 12 h in group D. The time to first analgesic request was prolonged with lower opioid consumption and more patient satisfaction in group M. Regarding nausea and vomiting, both groups were comparable.
Conclusion Magnesium sulfate as an adjuvant to bupivacaine in TAP block for TAH provided better analgesia compared with dexamethasone.

Keywords: dexamethasone, hysterectomy, magnesium sulfate, transversus abdominis plane block

How to cite this article:
Gad M, Nabil H, Elmetwally M, Elzahaby IA. Ultrasound-guided transversus abdominis plane block for total abdominal hysterectomy: comparison between magnesium sulfate and dexamethasone as adjuvants. Res Opin Anesth Intensive Care 2019;6:243-8

How to cite this URL:
Gad M, Nabil H, Elmetwally M, Elzahaby IA. Ultrasound-guided transversus abdominis plane block for total abdominal hysterectomy: comparison between magnesium sulfate and dexamethasone as adjuvants. Res Opin Anesth Intensive Care [serial online] 2019 [cited 2019 Oct 14];6:243-8. Available from: http://www.roaic.eg.net/text.asp?2019/6/2/243/260141

  Introduction Top

Total abdominal hysterectomy (TAH) operations use transverse lower abdominal incisions, which causes severe pain during the first 48 h, postoperatively. The multifactorial origin of pain after abdominal hysterectomy includes incisional pain, visceral pain, and dynamic pain, especially from the abdominal wall incision [1].

Therefore, a multimodal approach to postoperative analgesia after TAH is required to abolish nociceptive transmission from the abdominal wall incision and visceral sites. There has been a preference for opioids as a part of multimodal regimen despite the fact that utilization of opioids can lead to significant adverse effects, including nausea, vomiting, sedation, and respiratory depression, thus delaying early mobilization of patients. So, the transversus abdominis plane (TAP) block appears to be an ideal approach in relieving postoperative pain in those patients, especially when used as a component of multimodal analgesia regimen. The technical simplicity and reliable analgesia makes TAP block a preferred option for lower abdominal surgeries, as has been reported by the American Society of Regional Anesthesia [2].

The duration of TAP block is limited to the effect of administered local anesthetic (LA). However, different adjuvants have been used to increase the duration and improve the quality of the LA action to prolong the effect of TAP block with promising results [3],[4].

Magnesium plays an important role in the regulation of the amount of calcium inside the cells and control pain. Magnesium sulfate (MgSO4) helps in the reduction of the consumption of anesthetics during surgery if used via intravenous route. Moreover, it decreases the amount of postoperative opioids needed when added through epidural injection [5]. Evidence supporting the presence of N-methyl-d-aspartate (NMDA) receptors in skin and muscles [6] has led to the use of MgSO4 (NMDA antagonist) via different routes for brachial plexus block [7], including via neuraxial route [8]. Moreover, the analgesic effects of systemic and spinal corticosteroids in combination with LAs have been reported in human studies [9],[10]. Dexamethasone microspheres increased the block duration in human and animal studies [11],[12],[13]. Furthermore, dexamethasone has been shown to possess anti-inflammatory action [14]. This study aimed to compare the effect of adding either MgSO4 or dexamethasone to bupivacaine on the duration and quality of TAP block.

  Patients and methods Top

This study was carried out after approval by the Institutional Research Board on 60 adult female patients of American Society of Anesthesiologists I/II physical status scheduled for TAH under general anesthesia through pfannenstiel incision. Patient’s refusal of block, preexisting coagulation disorders, morbid obesity, local infection at the site of needle insertion for block, respiratory or cardiac diseases, patients on calcium channel blockers, or allergy to the drug under study were causes of exclusion from the study.

The patients were allocated randomly through sealed envelopes to get TAP block using the study solution [18 ml 0.25% bupivacaine (45 mg) with 2 ml (200 mg) of MgSO4 (M group, n=30) or 18 ml 0.25% bupivacaine (45 mg) with 2 ml (8 mg) of dexamethasone (D group, n=30)]. Randomization was done by using a computer-generated randomization schedule to confirm proper concealment of the study management from the investigators and the patients till the release of the final statistical results. The injectate in both groups was prepared by an independent anesthesiologist who is not involved in TAP performance, patient care, or data collection.

During preanesthetic visit, the patients were explained about the study purpose, advantages, and risks of procedure, and informed written consent was obtained. Patients were educated preoperatively about the use of visual analog scale (VAS) score for pain assessment on a 100 mm line (VAS; 0=no pain and 100=worst pain imaginable). A premedication of 1–2 mg of midazolam was administered intravenously, 20 min before induction of general anesthesia. Standard monitoring included noninvasive blood pressure, continuous ECG, pulse oximetry, and capnography. General anesthesia was inducted by propofol 1.5–2 mg/kg and fentanyl 1.5 µg/kg. Tracheal intubation was facilitated by cis-atracurium 0.1 mg/kg. Anesthesia was maintained with isoflurane 1 minimum alveolar concentration.

After induction of general anesthesia, TAP block was performed after draping the abdominal part between the twelfth rib bone and iliac crest with umbilicus using ultrasound (USG) probe with 38-mm broadband linear array (6–13 MHz; Siemens, Los Angeles, California, USA). While patient in the supine position, the USG probe was placed in a transverse plane to the lateral abdominal wall in between the lower costal margin and the iliac crest, in the mid axillary line. The needle was then positioned in plane under the USG probe, and then advanced till it reached the plane between transversus abdominis muscles (TAP) and the internal oblique. When reaching this plane, aspiration was done at first to exclude vascular injury, then the study solution was injected, which lead to expansion of the TAP and appeared as a hypoechoic space. The TAP block was then repeated on the opposite side by using the same technique and the same injectate.

After surgery, the patients were transported to the postanesthesia care unit where they were asked to rate pain they experience through VAS at time 0 (immediate after transport to postanesthesia care unit), 2, 4, 6, 8, 12, and 24 h postoperatively and recorded by an investigator who was blinded to the group assignment. Whenever the VAS was ≥30 mm, NSAID-ketorolac (Ketolac; Amriya, Alexandria, Egypt) intravenous 30 mg was administered. If pain is still ≥30 mm, pethidine in 25-mg increments was administered intravenously, and their total amount was recorded. Moreover, time to first analgesic request was recorded. Twenty-four hours after the surgery, the patients were asked to rate both vomiting, which were treated with antiemetics, metoclopramide 10 mg, on a four-point scale [none (1), mild nausea (2), severe nausea or vomiting once (3), vomiting more than once (4)] and their satisfaction on a three-point scale regarding pain management [highly satisfied (1), satisfied (2), or dissatisfied (3)].

In this study, the primary outcome measure was the postoperative VAS. The secondary outcome measures included the time to first analgesic request (the time interval from completing of LA administration till first need of rescue analgesic), total postoperative opioid consumption, nausea/vomiting score, and patient’s satisfaction. All the patients were monitored perioperatively for hemodynamic stability and any adverse effects.

Statistical analysis

Data were collected and tabulated in MS Excel 2010. Statistical analysis was performed by using SPSS software 17 (SPSS Inc., Chicago, Illinois, USA). One-sample Kolmogorov–Smirnov test was employed so as to determine whether data sets differed from a normal distribution. Normally distributed data were analyzed using a repeat-measures general linear model analysis of variance for time-related variables, whereas non-normally distributed data were analyzed by using the Mann–Whitney U-test, and categorical data were analyzed by using the χ2-test. P value less than 0.05 was considered statistically significant. The power of this clinical trial was prospectively calculated using the G power analysis program version 3 (Franz Faul, University Kiel, Germany). Using a priori analysis based on pilot study with accuracy mode calculations with VAS as the primary variant and assuming type-I error protection of 0.05 and an effect size convention of 0.9, a total sample size of 56 patients was needed for the study. To avoid dropout cases, this study added four cases, so the total number was 60 cases with 30 patients in each group, producing a power of 0.95.

  Results Top

A total of 60 patients were enrolled, allocated, and analyzed in this study ([Figure 1]). No significant differences for patient’s characteristics or duration of surgery were recorded ([Table 1]).
Figure 1 CONSORT diagram of the study.

Click here to view
Table 1 Patients’ demographics and duration of anesthesia of the groups

Click here to view

The difference in the VAS at 0, 2, 4, 6, and 24 h was found to be statistically insignificant in both groups. However, there was a statistically significant decrease in the VAS score at 8 and 12 h in group M compared with group D (P=0.022 and 0.019, respectively) ([Table 2]).
Table 2 Postoperative visual analog scale of the groups

Click here to view

Regarding time to first analgesic request, there was a significantly longer duration encountered in group M compared with group D (699±131 vs. 420±78 min; P<0.001). Group M recorded lower total 24-h pethidine consumption than D group (65±13 vs. 81±16 mg; P<0.001) ([Figure 2] and [Figure 3], [Table 3]).
Figure 2 Time to first analgesia request (min). Data are expressed as mean and SD. *Significant for D group in comparison with M group. P<0.05 is significant. D, dexamethasone; M, magnesium sulfate.

Click here to view
Figure 3 Total 24-h pethidine consumption postoperatively (mg). Data are expressed as mean and SD. *Significant for D groups in comparison with M group. P<0.05 is significant. D, dexamethasone; M, magnesium sulfate.

Click here to view
Table 3 Time to first analgesia request and total 24-h pethidine consumption postoperatively

Click here to view

Patient’s satisfaction score in M group was significantly higher when compared with D group (P=0.046). Meanwhile, there was no significant difference (P=0.69) in the incidence of nausea and vomiting between group M (14%) and group D (11%). None of the patients in either group had any other complication.

  Discussion Top

This study showed that the usage of 200-mg MgSO4 was superior to 8 mg dexamethasone as an adjuvant added to 18 ml bupivacaine 0.25% during TAP block on both sides for TAH operations. VAS was higher at 8 and 12 h with dexamethasone group. The time to first analgesic request was prolonged with lower opioid requirements in MgSO4 group. Moreover, patients were more satisfied in MgSO4 group. Regarding nausea and vomiting, both groups were comparable.

In various abdominal surgeries, multimodal regimen for postoperative analgesia has been established. TAP block is considered a suitable choice owing to its simplicity and effectiveness in providing analgesia, especially for surgical procedures where parietal pain is a significant component of postoperative pain. As the benefits of TAP blocks are related to enhanced accuracy of LA deposition, so the advent of USG guidance is beneficial [15]. Unfortunately, duration of TAP block is still limited by the efficacy of LA administered and the dose used, which is again dependent on the maximum permitted dose for that agent. This has led to the use of adjuvants such as clonidine and dexmedetomidine to prolong the effect of LA in TAP block [2].

The realization of analgesic potency of magnesium by virtue of its NMDA receptor antagonist has led to its use via various routes for providing pre-emptive analgesia and to prolong postoperative analgesia [5]. Recently, magnesium effects of NMDA receptor antagonism and sympathetic blocking have become evident, and it is now used to help to reduce the needs of anesthetics and pain medications. Magnesium blocks the effects of excitatory amino acids on NMDA receptors; moreover, it contributes to central sensitization [16].

Moreover, dexamethasone relieves pain as it reduces inflammation, blocks the transmission of nociceptive C-fibers in addition to suppresses ectopic neural discharge. The duration of postoperative analgesia is prolonged when dexamethasone is used as an adjunct for peripheral nerve blocks [17]. Castillo et al. [13] stated that addition of dexamethasone microspheres to bupivacaine resulted in prolongation of sciatic nerve blockade in rats. Droger et al. [11] have shown that dexamethasone incorporation into bupivacaine microspheres caused prolongation of the intercostal nerve blockade in sheep. These studies have attributed the prolongation of the block duration to the anti-inflammatory effect of steroids. Therefore, this study intended to compare MgSO4 and dexamethasone in USG-guided TAP block as adjuvants to bupivacaine in patients scheduled for TAH under general anesthesia.

In this study, MgSO4 was used in 200 mg based on the data from a study [18] which concluded that MgSO4 was used in 200 and 100 mg doses as a sole agent for postoperative analgesia in axillary block, and the duration of pain relief in MgSO4 groups were better than control group; however, the duration of pain relief with 200 mg MgSO4 was better than 100 mg MgSO4 without systemic or neurotoxicity.

Regarding total duration of analgesia, magnesium group recorded longer duration than dexamethasone group (M: 669±131 min vs. D: 420±78 min; P<0.001). Moreover, there were lower needs of total opioids consumed with magnesium group compared with dexamethasone group (M: 65±13 mg vs. D: 81±16 mg; P<0.001), indicating a longer pain free period and less requirement of analgesia in magnesium group.

Mahgoup [19] disagreed with this result, as he claimed that there is no significant difference in duration of analgesia during the addition of MgSO4 or dexamethasone to levobupivacaine during supraclavicular brachial plexus block given for upper limb surgery. One reason for this discrepancy may be owing to the duration of nerve block with levobupivacaine is much longer than with bupivacaine [20], which may mask the differentiation between the efficacy of the two studied adjuvants. The other reason may be different types of blocks under which the effect of these adjuvants was studied.This study shows significantly lower VAS scores with the use of magnesium at 8 and 12 h than dexamethasone group. Bondok and Abd El-Hady [21] also found significant reductions in postoperative VAS scores during the use of MgSO4 in femoral nerve blocks and intra-articular blocks. Regarding nausea and vomiting, there was no significant difference in nausea-vomiting scores in both groups, which may be attributed to lower opioid consumption in the magnesium group and also to the antiemetic properties of dexamethasone [22]. Satisfaction score was better with magnesium group than dexamethasone, and this issue concedes with the results of this study, as the former group showed lower VAS scores, decreased number of demand for rescue analgesia, and prolonged duration of analgesia. In both groups, there were no complications such as injury to nearby structures or visceral trauma owing to performance of the block under USG visualization.

There were a number of limitations of this research. First, no sham block group serving as a control group was established, which may be considered a limitation. The second limitation was the lack of assessment of the serum level of the studied adjuvants to explore whether their analgesic effect were locally only or owing to their systemic absorption. The third limitation was that it could not be sure if there was any block failure as it was proceeded under general anesthesia. These limitations are advised to be considered in the future.

  Conclusion Top

This study showed that MgSO4 as an adjuvant added to bupivacaine in TAP block prolongs the duration of analgesia, decreases VAS scores postoperatively, and decreases the number of demands for rescue analgesia more than dexamethasone. However, further studies are required to establish the efficacy of these adjuvants in TAP block and comparing them with a control group.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Brandsborg B, Nikolajsen L, Kehlet H, Jensen TS. Chronic pain after hysterectomy. Acta Anaesthesiol Scand 2008; 52:327–331.  Back to cited text no. 1
Sharkey A, Borglum J, Blanco R, McDonnell J. TAP block: past, present, and future. Am Soc Reg Anesth Pain Med 2014; 12:15–17.  Back to cited text no. 2
Kapral S, Goolann G, Walt B, Likar R, Sladen RN, Weinstabl C et al. Tramadol added to mepivacaine prolongs the duration of an axillary brachial plexus blockade. Anesth Analg 1999; 88:853–856.  Back to cited text no. 3
Pöpping DM, Elia N, Marret E, Wenk M, Tramèr MR. Clonidine as an adjuvant to local anesthetics for peripheral nerve and plexus blocks: a meta-analysis of randomized trials. Anesthesiology 2009; 111:406–415.  Back to cited text no. 4
Telci L, Esen F, Akcora D, Erden T, Canbolat AT, Akpir K. Evaluation of effects of magnesium sulphate in reducing intraoperative anaesthetic requirements. Br J Anaesth 2002; 89:594–598.  Back to cited text no. 5
Cairns BE, Svensson P, Wang K, Hupfeld S, Graven-Nielsen T, Sessle BJ et al. Activation of peripheral NMDA receptors contributes to human pain and rat afferent discharges evoked by injection of glutamate into the masseter muscle. J Neurophysiol 2003; 90:2098–2105.  Back to cited text no. 6
Lee AR, Yi HW, Chung IS, Ko JS, Ahn HJ, Gwak MS et al. Magnesium added to bupivacaine prolongs the duration of analgesia after interscalene nerve block. Can J Anaesth 2012; 59:21–27.  Back to cited text no. 7
Ghatak T, Chandra G, Malik A, Singh D, Bhatia VK. Evaluation of the effect of magnesium sulphate vs. clonidine as adjunct to epidural bupivacaine. Indian J Anaesth 2010; 54:308–313.  Back to cited text no. 8
[PUBMED]  [Full text]  
Glasser RS, Knego RS, Delashaw JB, Fessler RG. The perioperative use of corticosteroids and bupivacaine in the management of lumbar disc disease. J Neurosurg 1993; 78:383–387.  Back to cited text no. 9
Mirzai H, Tekin I, Alincak H. Perioperative use of corticosteroid and bupivacaine combination in lumbar disc surgery: a randomized controlled trial. Spine 2002; 27:343–346.  Back to cited text no. 10
Droger C, Benziger D, Gao F, Berde CB. Prolonged intercostals nerve blockade in sheep using controlled-release of bupivacaine and dexamethasone from polymer microspheres. Anesthesiology 1998; 89:969–974.  Back to cited text no. 11
Kopacz DJ, Lacouture PG, Wu D, Nandy P, Swanton R, Landau C. The dose response and effects of dexamethasone on bupivacaine microcapsules for intercostals blockade (T9 to T11) in healthy volunteers. Anesth Analg 2003; 96:576–582.  Back to cited text no. 12
Castillo J, Curley J, Hotz J, Uezono M, Tigner J, Chasin M et al. Glucocorticoids prolong rat sciatic nerve blockade in vivo from bupivacaine microspheres. Anesthesiology 1996; 85:1157–1166.  Back to cited text no. 13
Skjelbred P, Lokken P. Postoperative pain and inflammatory reaction reduced by injection of a corticosteroid. Eur J Clin Pharmacol 1982; 21:391–396.  Back to cited text no. 14
Atim A, Bilgin F, Kilickaya O, Purtuloglu T, Alanbay I, Orhan ME et al. The efficacy of ultrasound-guided transversus abdominis plane block in patients undergoing hysterectomy. Anaesth Intensive Care 2011; 39:630–634.  Back to cited text no. 15
Dubé L, Granry JC. The therapeutic use of magnesium in anesthesiology, intensive care and emergency medicine: a review. Can J Anaesth 2003; 50:732–746.  Back to cited text no. 16
Huynh TM, Marret E, Bonnet F. Combination of dexamethasone and local anaesthetic solution in peripheral nerve blocks: a meta-analysis of randomised controlled trials. Eur J Anaesthesiol 2015; 32:751–758.  Back to cited text no. 17
Goyal P, Jaiswal R, Hooda S, Goyal R, Lal J. Role of magnesium sulphate for brachial plexus analgesia. Internet J Anesthesiol 2008; 21:1.  Back to cited text no. 18
Mahgoup AAN. The addition of magnesium sulfate or dexamethasone to levobupivacaine for ultrasound-guided supraclavicular brachial plexus block for upper-limb surgery: a double-blinded comparative study. Res Opinion Anesth Intensive Care 2015; 2:116–120.  Back to cited text no. 19
Foster RH, Markham A. Levobupivacaine: a review of its pharmacology and use as a local anaesthetic. Drugs 2000; 59:551–579.  Back to cited text no. 20
Bondok RS, Abd El-Hady AM. Intra-articular magnesium is effective for postoperative analgesia in arthroscopic knee surgery. Br J Anaesth 2006; 97:389–392.  Back to cited text no. 21
Markman M, Sheidler V, Ettinger DS, Quaskey SA, Mellits ED. Antiemetic efficacy of dexamethasone: randomized, double-blind, crossover study with prochlorperazine in patients receiving cancer chemotherapy. N Engl J Med 1984; 311:549–552.  Back to cited text no. 22


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Patients and methods
Article Figures
Article Tables

 Article Access Statistics
    PDF Downloaded40    
    Comments [Add]    

Recommend this journal