FormalPara Key Summary Points

Selective block of ilio-inguinal nerve in association with transverse abdominis plane even with the use of the same dose of local anesthetic is more beneficial for post Cesarean pain rather than classical transverse abdominis plane block that is used as a default block for post Cesarean section pain.

The ilioinguinal-transversus abdominis plane significantly reduces the dose of opioid consumption and its side effects in comparison with transverse abdominis plane for post-Cesarean section pain.

Patients who received ilioinguinal-transversus abdominis plane are far more satisfied than those who received transverse abdominis plane block.

Introduction

The most frequent surgical operation performed globally is a Cesarean section [1]. After a Cesarean section, there are primarily two types of pain: somatic pain from the abdominal wall and skin incisions and visceral pain coming from the uterus [2]. Women who have recently given birth may endure tremendous discomfort from abdominal wall incisions [3]. The inappropriate management of this event may have significant implications on the mother's wellness in the postpartum phase because postoperative pain is a physiological process [4].

Ineffective pain management can cause neuroendocrine changes, which entail the hypophysis and adrenal glands responding negatively, which can have an adverse impact on a number of systems, including the cardiovascular, respiratory, gastrointestinal, and central neurological systems [4]. A woman's capacity to care for herself and her child may be hampered by pain [5]. An increased risk of opioid-related adverse effects, postpartum depression, and an increased likelihood that acute pain may turn into chronic persistent pain are all linked to inadequate pain management [5].

The multimodal analgesia protocol relies on the use of medications with several modes of action that have a synergistic analgesic effect with fewer side effects [5]. If opioids are used to treat pain, a multimodal regimen should be employed in a stepwise manner to make it easier to administer lower opioid doses [6]. Women who are ultra-rapid metabolizers of codeine frequently generate interindividual heterogeneity in the metabolism of opioids, as well as the risk of occurrence of maternal and neonatal ill effects [6]. The cornerstone for the treatment of postoperative pain is systemic or neuraxial opioids, although they are frequently accompanied by unfavorable side effects such as nausea, vomiting, respiratory depression, constipation, and pruritus [7].

Nonsteroidal anti-inflammatory medicines may not be sufficient as the only analgesic in the treatment of post-Cesarean pain [8]. The most widely used method for treating pain in these individuals in recent years has been a multimodal analgesic approach that includes abdominal wall nerve blocks in addition to parenteral analgesics [8].

The transverse abdominis plane (TAP) block, a recent regional procedure that inhibits the spinal neurons' anterior primary rami between T6 and L1, can lessen the somatic pain brought on by abdominal incisions [8, 9]. The nerves supplying the anterior abdominal wall flow through the TAP, a neurovascular plane situated between the internal oblique and transverse abdominis muscles [9].

An additional block used for post-operative analgesia following lower abdominal procedures is the iliohypogastric/ilioinguinal block (IHINB) [7]. IHINB has demonstrated efficacy in lowering morphine use without reducing negative effects [10]. Using lower segment Cesarean sections (LSCS), this study compared the effectiveness of TAP block versus I TAP (TAP block + ilioinguinal iliohypogastric nerve block) in minimizing the need for postoperative rescue analgesics.

Methods

A total of 210 patients between the ages of 18 and 45 who were scheduled for an elective lower segment Cesarean section (LSCS) under spinal anesthesia were randomly assigned to one of two groups, according to the American Society of Anesthesiologists physical status 1 and 2.

Ethics Statement

All patients provided written, fully informed consent after explaining the aim of this study. The study protocol was approved from the Faculty of Medicine Ethical Committee of Alexandria University (IRB approval number 0304697). All the participants were utilized in accordance with the Helsinki Declaration of 1975. Patients who refused to provide consent, had a known local anesthetic allergy, or had an infection at the site of the block were not included in the study.

The same anesthesiologist used 2.1 ml of 0.5% heavy bupivacaine and 25 µg fentanyl at the L3-L4 using Quincke's needle G 27interspace to administer spinal anesthesia to all patients after they entered the operating room. They were also connected to multichannel monitors and had intravenous lines inserted into them. Without using any drugs intraoperatively, the same individual managed all the patients.

After the procedure, patients were randomly assigned using a computerized random table that included a standard data collection sheet and an allocation card to the TAP block group or the ILIH plus TAP block group using the same dose of local anesthetic. The lead investigator carried out each block under strict aseptic conditions while employing an ultrasound-guided high-frequency linear probe (12 MHz) (SonoSite, Bothell, WA, USA).

When the probe was positioned in the TAP block group (group A), perpendicular to the mid-axillary line between the iliac crest and the costal margin, the three layers of abdominal muscles external oblique, internal oblique, and transversus abdominis were distinguished.

Between the internal oblique and the transverse abdominis muscle existed the transversus abdominis plane. The TAP was approached using an in-plane technique, a 23-gauge Quincke spinal needle, a 100-cm pressure monitoring line, a 50-ml syringe, 25 ml of bupivacaine 0.5%, 8 mg of dexamethasone, and 23 ml of normal saline to reach a concentration of 0.25%. Once the needle had reached the desired plane, 25 ml of the solution was administered, and the drug's distribution throughout the aircraft was watched. The same anesthesiologist used the same technique to perform the same action on the opposite side of the abdomen.

In the ITAP group (group B), the same technique as in group I's classical TAPB was used, but only 20 ml of the solution was injected into the TAP and 5 ml was specifically injected to block the ILIH using an out-of-plane technique. The probe was positioned medial to the lateral third of the line connecting the umbilicus and the anterior superior iliac spine (ASIS), with part of the probe resting on the ASIS. In the plane between the internal oblique and transversus abdominis muscles near the deep circumflex iliac artery, the ILIH nerve was discovered along with the ASIS, iliacus muscle, internal oblique, and transverses abdominis.

The same process was carried out on the opposite side, and the investigator only gathered procedural data and did not take part in the study in any other way. Patients were moved from the operating room to the post-anesthesia recovery room, and then to the postoperative ward, following the procedure. The patient received 1 g of paracetamol and 30 mg of ketorolac IV every 8 h in the postoperative ward.

At intervals of 1, 2, 3, 4, 8, 12, 16, 20, and 24-h following surgery, a blinded observer who was unaware of the patient's group assignment visited the patient to analyze the study's parameters and report those findings on a standard data collecting form. For the following 24 h, 6 mg of nalbuphine was administered intravenously whenever the patient complained of a VAS score more than or equal 4.

Every hour for the first 4 h and then every 4 h for the next 24 h following surgery, the effectiveness of analgesia was evaluated using the VAS score (ten-point pain scale, with 0 denoting no pain and 10 denoting severe pain; patients were asked to mark the pain score on the scale). It was noted when analgesia was first requested. Prior to hospital discharge, the patient satisfaction rating, and the 24-h nalbuphine requirement were noted.

Statistical Analysis

Data were entered into the computer and analyzed using a version of the IBM SPSS software program. 20.0 (IBM Corp., Armonk, NY, USA). Number and percentage were used to describe qualitative data. The normality of the distribution was examined using the Kolmogorov–Smirnov test. The range (minimum and maximum), mean, standard deviation, median, and interquartile range (IQR) were used to characterize quantitative data. At the 5% level, the significance of the results was determined. The tests used were chi-square test to compare two groups using categorical variables, correction for chi-square when more than 20% of the cells have an anticipated count of less than 5, Fisher's exact or Monte Carlo correction to compare two studied groups with normally distributed quantitative variables, use the student t test. To compare more than two groups with normally distributed quantitative variables, we used the F-test (ANOVA). To compare two groups with pairwise comparisons, we used the post hoc Tukey test. To compare two groups with abnormally distributed quantitative variables, we used the Mann–Whitney test. To compare more than two groups with abnormally distributed quantitative variables, use the Kruskal–Wallis test. A significant level is defined as p value < 0.05 or lower.

Results

The current study included a total enrollment of 200 participants and a response rate of 100%. Participants in group A were 31.68 years old on average, whereas those in group B were 31.81 years old on average, with a standard deviation of 6.46 years. Postoperative visual analogue pain scale. The study population's CONSORT flowchart can be seen in Fig. 1. Using a computer-generated table as a randomization approach, 227 patients between the ages of 18 and 45 with physical statuses 1 and 2 of the American Society of Anesthesiologists were scheduled for elective lower segment Cesarean section (LSCS) under spinal anesthesia. A total of 210 patients participated in the trial and gave their informed agreement, leaving 17 patients out (eight patients denied consent and nine patients did not match the inclusion criteria). They were divided into two groups, with 105 patients each in TAP (group A) and ITAP (group B) (Fig. 1).

Fig. 1
figure 1

Flowchart of the studied groups

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Regarding postoperative pain, there was no difference between the two groups at the first postoperative hour (p = 0.086), but a significant difference at 2, 3, 4, 8, 12, 16, 20, and 24 postoperative hours. Additionally, there was a significant difference in the VAS score between the two groups, with a significant reduction of VAS score in the ITAP group rather than the TAP group, (Table 1, Fig. 2).

Table 1 Comparison of median VAS score along different time points between two arms of treatment
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Fig. 2
figure 2

Comparison of median VAS score along different time points between two arms of treatment

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Additionally, the first request for analgesia in the TAP group was 10.06 ± 1.61 and 13.15 ± 1.85 for the ITAP group (p < 0.001) (Table 2, Fig. 3). Additionally, the mean opioid consumption for the TAP group was 8.97 ± 4.13 mg, while it was 3.50 ± 3.02 mg for the ITAP group, with a (p < 0.001) (Table 3, Fig. 4). Patient satisfaction was rated as 3 ± (2–4) in the TAP group and 4 ± (3–5) in the ITAP group, both with a p value less than 0.001, (Table 4, Fig. 5).

Table 2 Comparison of the mean between two arms of treatment about the first time to request analgesia (h)
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Fig. 3
figure 3

Simple bar of mean of mean first time to request analgesia (h) (± 95% CI) in the studied groups

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Table 3 Comparison of mean opioid consumption between both arms of treatment opioid consumption/mg, (all patients included)
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Fig. 4
figure 4

Comparison of mean opioid consumption between both arms of treatment

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Table 4 Comparison of median patient’s satisfaction score between both arms of treatment
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Fig. 5
figure 5

Comparison of median patient’s satisfaction score between both arms of treatment

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Discussion

The visual analogue score at rest in the first postoperative hour did not differ statistically significantly between TAP and ITAP blocks, but at all other periods of measurement, both at rest and during movement, the pain score significantly decreased [11]. Compared to TAPB, the ITAP nerve block considerably decreased the total nalbuphine intake, increased the time before the first analgesic request, and improved patient satisfaction [12, 13].

Our research was comparable to a controlled trial conducted in Ethiopia by Abiy et al. [14], which indicated that there was no statistically significant difference between the TAP and II-IH blocks for the postoperative pain score after CS, but that the II-IH block significantly decreased the total amount of tramadol used and extended the time to the first request for analgesia compared to the TAPB [14].

In line with our findings of nalbuphine, Ahemed et al. [15] conducted a randomized comparative observational study, which revealed that the II-IH nerve block following inguinal surgery significantly lowered both pain score and postoperative total tramadol use [15]. Mahmoud et al. [16] had 20 patients who were scheduled for CS participated in a pilot trial and got either a TAPB or an IL-IH nerve block for the treatment of post-CS pain. They concluded that IL-IH nerve block offers more effective post-CS analgesia than TAP block since the II-IH nerve block group's VAS score and nalbuphine consumption considerably decreased over the course of the first 24 h [16]. Faiz et al. [17] conducted prospective, randomized clinical research in which 90 patients who underwent open inguinal hernial surgery received either an IINB or TAP block for managing postoperative pain. Both at rest and during movement, NRS ratings were lower in the IINB group than in the TAP block group. Additionally, even though postoperative opioid needs were the same in both groups, analgesic satisfaction was considerably higher in the IINB group than the TAP block group. They concluded that US-guided IINB, as opposed to US-guided TAPB, offers better pain management following open inguinal hernial surgery [17].

In contrast to our study, Roshbeik et al. [18] conducted a randomized control trial on 70 patients scheduled for lower abdominal surgeries. They were divided into two equal groups, with group 1 receiving IINB and group 2 receiving TAPB. They discovered that group II had significantly lower postoperative pain scores and total analgesic consumption than group 1. They concluded that ultrasound-guided TAP block was superior to ultrasound-guided II/IH nerve block in reducing postoperative pain scores and decreasing total analgesic consumption [18].

Patient satisfaction was significantly higher in the ITAPB group compared to the TAPB group in this study. Also, the mean time request to the first analgesic was significantly longer in the ITAP group compared to TAPB. These findings are consistent with a prior comparative study conducted in Russia, which found that the II-IH block significantly prolonged the time to the first analgesic requirement following Cesarean delivery compared to the TAP block [19].

Our results were the same as those of the studies done by Sekali et al. [20] where it was discovered that patient satisfaction was higher in the II-IH block group compared to the sham block group, and postoperative tramadol use was considerably lower in females who received the II-IH block compared to those who received the sham block following Cesarean delivery (p < 0.05) [20]. In opposite to our study, Sharma et al. [21] conducted a double-blind, randomized, controlled trial on 116 patients who were split into two equal groups and scheduled for lower abdomen procedures under spinal anesthesia. Bilateral IL/IH block was given to group I, while bilateral TAPB was given to group T. Tramadol requirements were lower in group T compared to group I, while group T had a higher initial request for analgesic dose and a lower VAS score [21].

Limitations of the Current Study

There are many limitations of the current study including small sample size of patients and the gain of too much weight of some patients during pregnancy makes some difficulties in visualization of ilio-inguinal nerve. Also, some patients had previous experience of epidural analgesia in the previous Cesarean section, and they compare the level of analgesia with that provided by both TAPB and ITAPB.

Conclusions

According to the results of our investigation, ITAPB has a lower VAS score than TAPB. Following LSCS, ITAP block produced better postoperative analgesia and patient satisfaction than TAP block. Opioid use is much lower in the ITAP group compared to the TAP group. More studies including a large sample of patients are needed to confirm our results.