Bilateral Fascial Plan Block for Post Abdominoplasty Pain Control; Erector Spinae Plane Block Contrasted with Transversus Abdominis One

INTRODUCTION

Abdominoplasty is a widely performed cosmetic operation in the United States, with over 160,000 cases performed annually. ¹

Post-operative agony is an issue for both patients and physicians due to the immense incision and wounding of soft-tissue involved with this procedure. Historically, various nerve blocks have been used to enhance analgesia following abdominoplasty. ²

Although the transversus abdominis plane (TAP) block, a regional nerve block, had first been discussed in 2001, it has not been frequently used in cosmetic surgery. ³ This might be linked to the technique's blind nature as originally defined or to cosmetic plastic surgeons' unwillingness for using ultrasound guidance. Despite this, the TAP block has been effectively used in colorectal, hernia, and a variety of gynecologic surgeries. ⁴

Since opioid administration involves many unpleasant effects, including drowsiness, pruritus, vomiting, and nausea, regional opioid-free approaches are crucial to controlling post-operative pain in   Abdominal surgeries.⁵.

The ultrasonic-guided erector spinae plane (US-ESP) block is a unique method that targets the spinal nerves. Following injection, it was illustrated that the local Anaesthetic agent extends cranially and caudally throughout several dermatomal levels⁶. So many case reports and observational, randomized controlled trials have recorded that US-ESP block offered analgesia following various abdominal⁷, thoracic⁸, breast ⁹, and spinal surgeries¹⁰. ESP block offers favorable post-operative analgesia when administered in the T7 stage for abdominal procedures ⁷. T 4-5 level for breast⁹ and thoracic surgery⁸, a cadaver-based study showed that when introducing a 20 ml of a fluid at the T7 transverse phase, the fluid spreads cranially to the C7-T2 vertebra level and caudally to the L2-3 vertebra level10. Considering that LA spreads freely cranially and caudally throughout ESP, we presumed that ESP could be used adequately as an analgesic technique for abdominal surgeries, particularly those comprising various procedures and incisions in a single session.

Although the TAP block was described in 2001, It is not extensively used in cosmetic surgery. This may be connected to the blind kind of the treatment as mentioned or to the incapacity of cosmetic plastic surgeons to engage ultrasonography guidance. Yet, the TAP block in colorectal and gynecological surgeries has been effectively employed¹²

As mentioned in the classic literature, the TAP block is accomplished by injecting a single large dose of local anaesthesia into the plane located between the internal oblique and transversus abdominis, in a space spanning from the costal margin superiorly to end at the inguinal ligament and extend to the rectus abdominis. Based on the fact that the ventral rami of T7-L1 nerves pass through in this space from dorsal to anteriorly, the TAP technique has had the capability to block multiple cutaneous dermatomes with a single injection. The TAP space can indeed be accessed thru a variety of routes, such as the lumbar subcostal approach (petit triangle) outlined by Hebbard¹³. Fortunately, it is often performed through the use of the lumbar Petit triangle using a lateral approach, which consistently spreads up to the T10 dermatome, thus block the abdomen's lower quadrant effectively. This, however, is reportedly a tough approach to take for overweight patients¹⁴

The primary objectives were about to analyze post-operative pain severity as evaluated by the VAS score, the time needed for the first rescue analgesia (pethidine), the number of doses administered, and the overall amount of pethidine administered within first 24 hours after the procedure. Secondary objectives concerned patient satisfaction.

PATIENTS AND METHODS

This study was a clinical prospective randomized single-blinded trial approved by the Ethics and Scientific Committee at Al- Azhar University's Faculty of Medicine in Cairo for boys.

Between July 2020 and March 2021, patients who were admitted for abdominoplasty surgeries at Al- Azhar University Hospitals (Alhussein and Bab al sharia hospitals) in Cairo, Egypt, have been included in the study. This research surveyed 60 patients aged 21 to 40 years with a body mass index (BMI) of 25 to 35kg/m2, who fulfilled the American Society of Anesthesiologists (ASA) physical status I or II and had been planned for elective abdominoplasty under general anaesthesia.

The researchers have excluded patients with coagulation dysfunction or those on anticoagulants, altered mental state, a known case of allergy to the research medications (bupivacaine or pethidine), chronic pain, ASA ≥ III, or localized infection at the injection site from the study.

Participants were admitted after signing an affirmative consent application stating that they had been giving consent to participating in a clinical study and that their details would remain confidential. They would receive the same quality of healthcare as all operating theatre patients and it would not be declined medication for refusing to participate in the study. The patient was informed of the research process verbally and in writing. Since the patient receives no direct benefit and inflicts no extra costs as a result of participation in the trial, the results could be used to influence future local practice. Additionally, individuals had the option of withdrawing from the research at any time and would continue to receive prescribed therapy. However, four patients met the exclusion criterion, two patients experienced significant blood loss and hemodynamic instability intra - operative, and three patients refused to participate, leaving the trial with 51 patients, randomly divided into 25 patients in the (ES group) and 26 patients in the control group using a computer-generated algorithm (TAP group).

Given that the mean standard deviation in the ESP block is 4.7- 3.7 and 2.5 - 1 in the TAP block, so the overall sample size would have been 48 patients (24 of each group) using Open-Source Epidemiologic Statistics for Public Health version 3.01 software (OPENEPI) with a 95% standard error and an 80% power of examination. (No comparable experiments have yet been conducted). Finally, 51 patients were included in the sample, 25 of whom were randomly assigned to the ESP group and 26 of whom were randomly assigned to the control group (TAP group)

Techniques of Anesthesia and Blocking;

All patients would be told of the VAS score one day pre - operative. The VAS score is depicted by a 10-cm scale with the right border labeled "worst pain conceivable" and the left border labeled "no pain.". The patient would be asked to mark a point on the line to indicate the discomfort level they are now experiencing. Consequently, both patients were evaluated routinely prior to surgery. Both patients' baseline vital signs were collected in the preparatory room (blood pressure, oxygen saturation, respiratory rate, and heart rate).

In the operating room, both patients were followed up using a GE Healthcare model B40i monitor, that included end tidal CO_2, oxygen saturation, electrocardiography, and noninvasive blood pressure monitoring.

To administer IV fluids and drugs, an intravenous (IV) line was established. Both propofol 2 mg/kg and Fentanyl 1 ug/kg had been used to induce anaesthesia, and 0.5-0.6 mg/kg IV atracurium was used to ease endotracheal tube placing. Anesthesia was achieved with 1 MAC isoflurane in 50% oxygen and 50% air, 0.1 mg/kg/h atracurium, and 0.5 ug/kg/h fentanyl.

After the surgical operation was performed and before the muscle relaxant was reversed, the ES group moved to lateral position and  an ESP block was done  at T9 level, following skin scraping with a disinfectant. The seventh cervical vertebrae's spine was used as a reference point for counting down to the ninth thoracic vertebrae's spine (T9). A sagittal 3 cm lateral to the T9 spinous phase, a high-frequency linear (6–13 MHz) ultrasound probe (Sonosite, Fujifilm, Edge II) was positioned. The transverse process (TP) and erector spinae were identified as hyperechoic shadows. A 22-gauge short bevel needle will be inserted cranial to caudal against the transverse process (TP) in the plane of the ultrasound transducer before the needle touches the TP and crosses all the muscles. On ultrasound imaging, the needle tip positioning could be confirmed by apparent normal saline solution between the ESM the TP. After the appropriate needle tip was obtained, 0.25% bupivacaine 20 mL was delivered. The process is repeated on the opposite side of the spine, pursuing this very same steps. The local anaesthetic distribution was confirmed sonographically by the distinguished spread of LA in the corresponding paravertebral spaces as an anechoic shadow between T7 and T12.

In the T group (UGTAPB), the same transducer (6–13 MHz) would be located in short-axis plane, mid-way between the iliac crest and the lower costal margin, in the mid-axillary line; the position is supine. The three abdominal wall muscles were visualized and identified from inside to outside as transversus abdominis, internal oblique and external oblique. The needle was indeed be inserted and progressed ventral to dorsal in-plane under simultaneous visualization until the needle tip is recognizable between the transversus abdominis and the internal oblique muscle. Following negative aspiration, 0.25 % bupivacaine 20 mL was injected. Distention of the plane with the LA as an elongated oval pocket is indicator of the injection's efficacy. On the other side, the operation was repeated in the same way. Isoflurane was then discontinued and Atracurium was reversed with neostigmine 0.05 mg/kg plus atropine 0.01 mg/kg. patients were extubated and shifted to the recovery room.

The primary and secondary results were determined in the recovery room and after complete recovery from general anesthesia by the outcomes inspector (An anesthesiologist not participating in the trial).

The primary outcomes assessed were the following:

(1) If the VAS score for pain severity was 4 at 30 minutes, then at  2, 4, 6, 8, 12, 16, 20, and 24 hours postoperatively, IV boosts of 40 mg pethidine (rescue analgesic) were administered. Patients were relocated to a post-operative pethidine analgesic scheme following rescue analgesic administration; 5 mg/kg IV as requested, with a median daily dosage of 200 mg.

(2) The cumulative amount of pethidine administered during the first 24 hours after surgery.

Secondary results quantified include the following:

(1) Total patient satisfaction 24 hours postoperatively: all patients would be asked to score their overall level of analgesia satisfaction on a three points verbal scale (1 indicates totally inadequate analgesia, 2 indicates adequate analgesia, and 3 indicating admirable analgesia).

(2) Some indication that the block strategies are having an adverse effect (, hematoma formation, bowel perforation, and pneumothorax). Both adverse events were recorded and treated promptly.

Statistical analysis:

The mathematical package for social sciences, version 20.0, was used to interpret the collected data (SPSS Inc., Chicago, Illinois, USA). The mean and standard deviation of quantitative results is calculated (SD). Frequency and percentages were used to express qualitative results.

We conducted the following tests:

For comparing two means, the independent-samples t-test of significance was used.

The Mann Whitney U test is used to compare two groups of non-parametric data.

To equate proportions between qualitative criteria, the Chi-square (x2) test of significance was used.

The confidence interval was set to 95%, and the appropriate margin of error was set to 5%. As a result, the following p-value was found significant:

Possibility (P-value);

–P-value of 0.05 was considered significant.

–P value of 0.001 was deemed highly significant.

–P-value of more than 0.05 was considered insignificant.

RESULTS

The study enrolled 51 patients, ranging in age from 21 to 40 years, BMI of 25 to 35 kg/m2 and ASA I or II, who were admitted for abdominoplastic surgeries under general anesthesia.

In terms of demographic evidence, no statistically difference exists between the ES and TAP groups. regards of age (years), gender, BMI [wt/(ht)2], and physical state (ASA), as seen in (Table 1).

There were statistically variations in VAS scores between the ES and TAP groups at 8 and 12 hours. Additionally, patients in both groups consistently exhibited a slightly lower VAS score, indicating progress in both groups, but more specifically in the ES community, as demonstrated by the p-value (p0.05) in (Table 2 and figure 1).

Fig 1: Comparison between ES Group and TAP Group according VAS score.

With regards to the first analgesic pethidine dosage postoperatively, there was a statistically significant delay in the ESP community compared to the TAP group, and with regards to the average volume of pethidine consumed in 24 hours, there was a highly significant drop in the ES group compared to the TAP group, as seen in (Table 3).

When comparing the amount of rescue pethidine doses administered within the first 24 hours between the ES and TAB groups, a statistically important increase in the number of rescue doses was observed in the TAP group relative to the ES group, as seen in (Table 4 and figure 2).

Fig 2: Comparison between ES Group and TAP Group according the number of rescue pethidine doses.

In terms of patient satisfaction in the first 24 hours, while there is a statistically meaningful variance between the E and T groups (satisfied and extremely satisfied in E group 22 patients (88 percent) vs. 21 patients (80 percent) i group, the difference is not statistically significant (Table 5).

Table 1: Comparison between the ES and TAP groups. regards of age (years), gender, BMI [wt/(ht)2], and physical state (ASA).

Table 2: VAS scores between the ES and TAP groups

Table 3: Comparison between ES Group and TAP Group regarding pethidine dosage postoperatively. Data expressed as Mean ± SD (T-Independent Sample t-test; P-value>0.05 NS; *p-value

Table 4: Comparison between ES Group and TAP Group regarding the amount of rescue pethidine doses administered within the first 24 hours. (*p-value

Table 5: Comparison between ES Group and TAP Group regarding patient satisfaction