European Journal of Cardiovascular Medicine

One of most common inguinal operations performed on men is open inguinal hernia repair.   In addition to increasing morbidity and lengthening hospital stays, untreated postoperative pain puts patients at risk for developing chronic pain.  [1]

Nowadays, regional blocks, as a part of multimodal analgesic strategies, are considered the standard of care in surgical patients [2,3].  Various blocks utilized for inguinal hernia repair include TAP (Transversus Abdominis Plane) block, Ilioinguinal-Iliohypogastric block, ESP (Erector Spinae Plane) block, Paravertebral block, Retrolaminar block, QL (Quadratus Lumborum  block)  and local infiltration  [4,5,6,7,8,9 ].  These techniques show varying degrees of efficacy, technical challenges, and complications.

Purpose of the present research is to assess effectiveness of TFB, a technique that is comparatively underutilized for pain management during inguinal hernia surgery. TFB targets specific nerves T11, T12, as they emerge from the intervertebral foramen within the transversalis fascia plane [10].  After inguinal hernia surgery, we compare TFB with the widely utilized TAP block [11] for postoperative pain control.  Comparing analgesic effectiveness of TFB and TAP block is the study's goal.  By keeping track of the time until the first analgesic need, we are able for comparing the length of analgesia that these two blocks provide.  Comparing total amount of analgesics needed in first twenty-four hrs after surgery is our research secondary goal. 

This prospective, randomized, double-blind, comparative interventional study was conducted at a tertiary care facility after obtaining approval from the Institutional Ethics Committee, D. Y. Patil Medical College, Kolhapur (Approval date: 9 dec 2022). The study was also registered with the Clinical Trials Registry of India (CTRI/2023/08/2022-23). A total of 46 patients scheduled for open inguinal hernia repair were enrolled after fulfilling the inclusion and exclusion criteria. Prior to participation, the study protocol was explained to all patients, and written informed consent was obtained. Patients with obesity, bilateral inguinal hernias, a preference for laparoscopic surgery, known coagulopathy, or allergy to local anesthetics were excluded. Participants were randomly allocated into two equal groups (n=23 each) using a computer-generated randomization sequence. Group assignment was concealed using an opaque sealed envelope technique (Figure 1). All individuals underwent preoperative optimization and routine investigations according to institutional protocols. On the night before surgery, patients received 0.5 mg of oral alprazolam and were kept nil by mouth (NBM) overnight for at least eight hours. On the day of surgery, spinal anesthesia was administered with 3.5 mL of 0.5% heavy bupivacaine at the L3–L4 interspace. Intraoperatively, all patients received intravenous fentanyl (2 µg/kg) and midazolam (0.04 mg/kg) for sedation and analgesia. Open inguinal hernia repair with mesh placement was performed for all patients in the supine position. At the end of the surgery, the assigned block was performed in supine position under strict aseptic precautions using a Sonosite Turbo M ultrasound machine with a high-frequency linear probe and a 10-cm Stimuplex needle, inserted from the anterior approach. Group A: TAP Block (n = 23) The ultrasound probe was placed transversely along the midaxillary line between the costal margin and iliac crest. After identifying the three layers of the anterior abdominal wall, the needle was advanced under real-time ultrasound guidance, and 20 mL of 0.25% bupivacaine with adrenaline (5 µg/mL) was deposited between the internal oblique and transversus abdominis muscles (Images 1 and 2). Group B: Transversalis Fascia Block (TFB) (n = 23) For the TFB, the probe was placed transversely along the midaxillary line at the level of the umbilicus and then slid posteriorly to visualize the tapering of the transversus abdominis muscle. The transversalis fascia was identified, and the needle was advanced to deposit 20 mL of 0.25% bupivacaine with adrenaline (5 µg/mL) between the transversalis fascia and the transversus abdominis muscle (Images 3 and 4). Postoperatively, patients were monitored for pain using the Visual Analogue Scale (VAS) at 4-hour intervals for 24 hours. The time to first rescue analgesic and total 24-hour analgesic requirement were recorded for comparison between groups Observations Postoperatively, all patients were monitored for 24 hours. Pain assessment was performed using the Numerical Rating Scale (NRS) at 4-hour intervals. The ward nurse was instructed to administer rescue analgesics in a stepwise manner: First rescue dose: Intravenous paracetamol (100 mL) infused over 20 minutes, if the patient complained of pain or if the NRS score exceeded 4. Second rescue dose: If pain persisted after the first intervention, intravenous tramadol (100 mg) diluted in 100 mL of Ringer’s Lactate (RL) was administered as a drip over 20 minutes. Subsequent doses: If further analgesia was required within the 24-hour postoperative period, intramuscular diclofenac sodium (75 mg) was given. The time to administration of the first rescue analgesic was recorded to determine the duration of the block. The total requirement of rescue analgesics within 24 hours was also documented. Patients were additionally monitored for any block-related complications, including swelling, pain, or induration at the injection site Statistical Analysis A master chart was prepared using MS Excel 2007, and statistical analysis was performed using SPSS (Version 28) and G*Power (Version 3.1.9.4) software. Quantitative variables were compared using the unpaired t-test, while qualitative variables were analyzed using Fisher's exact test or the Chi-square test, as appropriate. A p-value of < 0.05 was considered statistically significant. The sample size was calculated based on standard deviation (SD) values from a previous study (SD₁ = 4.1, SD₂ = 3.64) using a 95% confidence interval and 80% study power, according to Cohen’s d effect size formula. The minimum required sample size was determined to be 21 patients per group. To compensate for an anticipated 10% dropout rate, 23 patients were enrolled in each group, resulting in a total sample size of 46 participants.

A total of 46 patients were enrolled and equally randomized into two groups (n = 23 each). All participants completed the study, and no data were excluded from the final analysis.

Demographic Characteristics

The demographic variables, including age, body mass index (BMI), and ASA physical status, were comparable between the two groups, with no statistically significant differences (p > 0.05) (Table 1). This indicates that both groups were homogenous at baseline.

Duration of Analgesia

The mean duration of postoperative analgesia, calculated as the time to the first rescue analgesic, was 10.9 ± 5.6 hours in Group A (TAP block) and 14.26 ± 5.04 hours in Group B (TFB).

The difference between the groups was statistically significant (p = 0.02), demonstrating that the TFB provided a longer duration of analgesia compared to the TAP block (Table 2, Figure 2).

Postoperative Pain Scores

Postoperative pain was assessed using the Numerical Rating Scale (NRS) at 4-hour intervals over 24 hours.

Group B consistently demonstrated lower NRS scores compared to Group A at all time points except at 24 hours, where the difference was not statistically significant (p > 0.05).

The difference was statistically significant at all other time intervals (p < 0.05) (Table 3, Figure 3).

Total 24-hour Analgesic Requirement

The total number of rescue analgesic doses administered within the first 24 hours was significantly lower in Group B (1.0 ± 0.52) compared to Group A (1.5 ± 0.79).

This difference was statistically significant (p < 0.05) (Table 4).

Complications

No block-related complications, such as local swelling, induration, or signs of local anesthetic systemic toxicity, were observed in either group during the 24-hour postoperative monitoring period.

FIG 1: CONSORT Flow chart diagram of patient Enrollment , Allocation ,follow-up and analysis

Table 1:  Demographic variables in both the groups

Table 2:  Duration of  both the blocks

Table 3:  NRS  score at various point intervals

Table 4: Total Rescue analgesics over 24 hrs

Moderate postoperative pain is commonly associated with open inguinal hernia procedures, with pain intensity typically peaking within the first 24 hours following surgery. Inadequate postoperative pain control can lead to persistent discomfort, and up to 30% of patients may develop chronic pain as a consequence of insufficient pain management.[8] According to the PROSPECT guidelines, a multimodal analgesic approach is strongly recommended, incorporating the use of fascial plane blocks to optimize perioperative pain control.[9]

This study compared the Transversalis Fascia Block (TFB) and the Transversus Abdominis Plane (TAP) block for postoperative analgesia in open inguinal hernia surgery. The sensory innervation of the inguinal region arises from the T10–L1 segments, with the ilioinguinal

nerve (IIN) and iliohypogastric nerve (IHN) originating

from T12–L1, and the genital branch of the genitofemoral nerve innervating the hernial sac.[10]

TFB achieves more comprehensive analgesia by depositing local anesthetic between the transversus abdominis aponeurosis and transversalis fascia, effectively targeting the IIN and IHN before they pierce the transversus abdominis muscle. This allows for potential cranial spread to thoracic nerves and caudal spread to L1–L2, providing wider coverage compared to the TAP block, which primarily deposits the drug at a higher T10 level with limited extension to T11–L1.[11]

Previous studies have highlighted the benefits of combining or comparing fascial plane blocks in hernia surgeries. Hosalli et al. demonstrated that combining a TAP block with IIN and IHN blocks was superior to IIN and IHN blocks alone for postoperative pain control.[12] Similarly, Serifsoy et al. and Chilkoti et al. reported enhanced analgesic outcomes with TFB compared to TAP block in lower segment cesarean section (LSCS) surgeries.[13,14]

Black et al. demonstrated the utility of TFB in iliac bone grafting procedures,[15] while Lopez et al. found TFB to be superior to TAP block for postoperative analgesia in outpatient hernia surgeries in a retrospective analysis.[16]

In pediatric populations, Abdelbasar et al. confirmed the efficacy of TFB in a randomized controlled trial (RCT),[17] and Paolo et al. published a case report demonstrating the successful use of TFB in a high-risk cardiac patient undergoing hernia surgery.

Furthermore, Fouad et al. compared the Quadratus

Lumborum (QL) block with TFB and concluded that TFB

was technically easier to perform while providing similar analgesic efficacy.[18]

In the present study, TFB provided significantly longer postoperative analgesia, with a higher mean duration before the first rescue analgesic, and consistently lower NRS pain scores at all time points except at 24 hours. Additionally, the total 24-hour rescue analgesic consumption was significantly lower in the TFB group compared to the TAP group. These findings corroborate the results of Lopez et al. and Abdelbasar et al., further supporting the role of TFB as a superior option for postoperative pain management in inguinal hernia surgery.

While both TFB and QL block provide effective analgesia, TFB offers a more direct and targeted approach to the IIN and IHN, with a more caudal and anterior injection point, making it technically simpler to perform without compromising efficacy — consistent with the observations of Fouad et al.[18]

Limitations

The limitations of this study include its single-center design, small sample size, and a relatively short follow-up period limited to 24 hours. Additionally, optimal patient positioning for block administration was not specifically evaluated. Future studies with larger cohorts, multicenter participation, and extended follow-up periods are needed to assess the role of TFB in the prevention of chronic postoperative pain and to refine its technical aspects.

Based on our findings, TFB offers better postoperative analgesia in comparison to TAP block in open hernia surgeries. TFB dramatically lowers pain ratings and the requirement for rescue analgesics during the first twenty-four hours after surgery.

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8.      Ayyanagouda B, Hosalli V, Hiremath P, Ambi U, Hulkund S. Comparative efficacy of postoperative analgesia between ultrasound-guided dual transversus abdominis plane and Ilioinguinal/Iliohypogastric nerve blocks for open inguinal hernia repair: An open-label prospective randomised comparative clinical trial. Indian Journal of Anaesthesia. 2019;63(6):450.

9.      Bansal T, Kamal K, Jain P, Ahlawat G. A comparative study to evaluate ultrasound-guided transversus abdominis plane block versus ilioinguinal iliohypogastric nerve block for post-operative analgesia in adult patients undergoing inguinal hernia repair. Indian Journal of Anaesthesia. 2018;62(4):292.

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12.   1.Serifsoy TE, Tulgar S, Selvi O, Senturk O, Ilter E, Peker BH, et al. Evaluation of ultrasound-guided transversalis fascia plane block for postoperative analgesia in cesarean section: A prospective, randomized, controlled clinical trial. Journal of Clinical Anaesthesia [Internet]. 2020 Feb [cited 2019 Nov 1];59:56 60. Available from: https://www.sciencedirect.com/science/article/pii/S0952818019305483

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