Oblique subcostal transversus abdominis plane block versus transmuscular quadratus lumborum block for postoperative analgesia and quality of recovery in laparoscopic gynecological surgery: a prospective randomized controlled double-blind trial.

The present study was designed as a prospective, randomized, controlled, double-blind trial and was registered retrospectively at ClinicalTrials.gov ( NCT06017401 ; registered on August 20, 2023) following approval by the Clinical Trials Ethics Committee of Uludag University School of Medicine (Approval No: 2023-11/9; May 16, 2023). This trial was conducted in accordance with the principles of the 2013 Declaration of Helsinki. All participants provided written consent forms for participation in the study. This manuscript adhered to the CONSORT guidelines. The study was conducted between May and November 2023 at a tertiary university hospital. Patients aged 18–65 years, who had an American Society of Anesthesiologists (ASA) physical status I-III, a body mass index (BMI) of 18–25 kg/m², and scheduled for elective laparoscopic gynecological surgery lasting 45 to 120 min using 3 or 4 trocars were included in the study. Patients with a known allergy to local anesthetics, known or suspected coagulopathy, infection at the injection site, severe neurological or psychiatric disorders, severe cardiovascular disease, liver failure, renal failure, or chronic opioid use (> 6 months) were excluded from the study. Patients scheduled for elective laparoscopic gynecological surgery and met the inclusion criteria were informed about the regional anesthesia they would receive. The VAS assessment was explained to the patients in detail, and their age, ASA physical status, height, weight, BMI, and preoperative QoR-15 scores were recorded. The Turkish version of the QoR-15, which has demonstrated acceptable validity, reliability, and responsiveness in Turkish patients, was used [ 15 , 16 ]. The QoR-15 questionnaire consists of 15 questions assessing five domains: pain, physical comfort, physical independence, psychological support, and emotional state. Patients marked their state on a 10 cm horizontal line. Positive items were scored on a scale ranging from 0 (none of the time) to 10 (all of the time), while negative items were scored from 0 (all of the time) to 10 (none of the time). As a result, a patient can achieve a total score ranging from 0 to 150. A higher score on the questionnaire indicates a better QoR. A total of 73 patients, who met the inclusion criteria, were randomly allocated to the OSTAP ( n  = 36) or the TQL group ( n  = 37) using the closed-envelope method. Randomization was performed using a computer-generated allocation list created with Microsoft Excel (version 16.73) in a 1:1 ratio. Allocation concealment was ensured using sequentially numbered, opaque, sealed envelopes prepared by an anesthesia nurse who was not involved in the study. The envelopes were opened sequentially after patient enrollment, and group allocation was recorded. The study was designed as a double-blind trial. Patients and the pain management nurse, who was not involved in block administration, were blinded to group allocation. The anesthesiologist performing the block was aware of group allocation, as required by the procedure. Blocks were performed under intravenous (IV) sedation before induction of general anesthesia, and to maintain patient blinding, participants were informed that a local anesthetic would be administered prior to needle insertion; however, no details were provided regarding the block technique, injection site, or number of injections. Following standard ASA monitoring (pulse oximetry, non-invasive blood pressure measurement, electrocardiography), an IV line was established with a 20-gauge (G) cannula, and 0.9% saline infusion was initiated at a rate of 3 mL/kg/hour. Block procedures were performed by a single anesthesiologist experienced in regional anesthesia, following premedication with 0.02 mg/kg IV midazolam and 1 mcg/kg IV fentanyl administered at least 30 min before the induction of general anesthesia. In the OSTAP group, after ensuring sterile conditions, a high-frequency (4–12 MHz) linear transducer (Xperius ® , Philips Ultrasound, Inc.) was placed transversely below the xiphoid process of the sternum while the patient was in the supine position. The linea alba was visualized in the center, with the rectus abdominis muscles on either side. Transducer was moved laterally along the oblique subcostal line, parallel to the costal margin and at an oblique angle to the sagittal plane, starting from the end of the xiphoid process. Once proper visualization was achieved, the area between the posterior sheath of the rectus abdominis and the fascia of the transversus abdominis was targeted and a 22-G, 80-mm needle (Stimuplex ® Ultra 360 ® , B-Braun) was inserted in-plane near the xiphoid process and advanced in an inferolateral direction. Hydrodissection was performed with 1–2 ml of local anesthetic to confirm the needle tip placement. Thereafter, 20 ml of 0.25% bupivacaine was administered into the space between the posterior sheath of the rectus abdominis and the fascia of the transversus abdominis, and the same procedure was repeated on the opposite side (Fig.  1 A). Fig. 1 Sonogram of the oblique subcostal transversus abdominis plane and transmuscular quadratus lumborum block. A Sonogram of the oblique subcostal transversus abdominis plane block. B Sonogram of the transmuscular quadratus lumborum block. RA = Rectus abdominis muscle, TA = Transversus abdominis muscle, QL = Quadratus lumborum muscle, PM  =  Psoas major muscle, ES = Erector spinae muscle, TP = Transverse process Sonogram of the oblique subcostal transversus abdominis plane and transmuscular quadratus lumborum block. A Sonogram of the oblique subcostal transversus abdominis plane block. B Sonogram of the transmuscular quadratus lumborum block. RA = Rectus abdominis muscle, TA = Transversus abdominis muscle, QL = Quadratus lumborum muscle, PM  =  Psoas major muscle, ES = Erector spinae muscle, TP = Transverse process In The TQL group, after positioning the patients in the lateral decubitus position and ensuring sterile conditions, a low-frequency (2–5 MHz) convex transducer (Xperius ® , Philips Ultrasound, Inc.) was placed transversely at the L4 level, just above the iliac crest, along the mid-axillary line. After visualizing the external oblique, internal oblique, and transversus abdominis muscles, transducer was moved dorsally in a transverse orientation until the QL muscle was identified at its attachment to the lateral edge of the transverse process of the L4 vertebral body. By applying a caudal tilt, the acoustic shadow of the L4 transverse process was visualized, with the erector spinae muscle posteriorly, the QL muscle laterally, and the psoas major (PM) muscle anteriorly, forming the shamrock sign (Fig.  1 B). After a clear image of the QL muscle was obtained, a 22-G, 80-mm needle (Stimuplex ® Ultra 360 ® , B-Braun) was directed from posterolateral to anteromedial with the in-plane technique. The needle tip passed through the QL muscle, punctured the ventral fascia of the QL muscle, and was advanced into the plane between the QL and PM muscles. Hydrodissection was performed with 1–2 ml of local anesthetic to confirm the needle tip placement. Then 20 ml of 0.25% bupivacaine was administered into the plane between the fascial layers of the QL and PM muscles, and the same procedure was repeated on the opposite side. After block administration, general anesthesia was induced in all patients with IV lidocaine 1 mg/kg, propofol 1-2.5 mg/kg, fentanyl 1 mcg/kg, and rocuronium 0.6–1.2 mg/kg, followed by endotracheal intubation. Anesthesia was maintained with a 50% air and 50% O 2 mixture, set to a minimum alveolar concentration of 1, using sevoflurane and a fresh gas flow of 2 L/min. Patients were placed in the lithotomy and trendelenburg position. Surgical procedures were performed using three or four trocars. After achieving abdominal access with the Veress needle and establishing pneumoperitoneum, intraabdominal pressure was maintained at 12–14 mmHg. Four trocars were used only in surgeries for deeply infiltrating endometriosis (DIE), whereas three trocars were used in other procedures. The 10-mm trocar was placed at the umbilicus, while the 5-mm trocars were positioned 2 cm medial to the right and left anterior superior iliac spines (ASIS). In surgeries that required four trocars, the fourth trocar was placed 5 cm above the left ASIS. All patients received 1 g IV paracetamol and 20 mg IV tenoxicam prior to the surgical incision, while 10 mg IV metoclopramide was administered 30 min before the surgery was completed. Patients were extubated after the administration 2–4 mg/kg IV sugammadex. Anesthesia time and surgical time were recorded. During the postoperative period, VAS scores at rest and during movement were recorded at 0, 30 min, 1, 2, 6, 12, 18, and 24 h and before discharge, using a scale ranging from 0 (no pain) to 10 (worst possible pain). Pain during movement was defined as the pain experienced during standardized mobilization, including standing up and walking a few steps with assistance. IV paracetamol 500 mg was administered every 6 h when the VAS score was ≥ 4 (maximum daily dose, 2 g). and if it remained ≥ 4 after 30 min, IV tramadol 1 mg/kg was given as a rescue analgesic (a maximum daily dose of 400 mg). All patients were mobilized 6 h after surgery and discharged following 24 h of observation. The primary outcome of the study was postoperative tramadol requirement. Secondary outcomes included postoperative paracetamol requirement, time to first paracetamol and tramadol requirement, total paracetamol and tramadol consumption, VAS scores measured at rest and during movement at 0, 30 min, 1, 2, 6, 12, 18, 24 h postoperatively and before discharge, and QoR-15 scores preoperatively and 24 h postoperatively. A pain management nurse, who was not involved in the block administration and was blinded to the patient’s group assignment, recorded the total analgesic consumption, the times of paracetamol and tramadol administration, VAS scores, and nausea and vomiting during the first 24 h postoperatively. Patients completed the QoR-15 questionnaire at the 24th postoperative hour. Potential block-related adverse effects, such as hematoma or infection at the injection site, abdominal organ injury, lower extremity muscle weakness, and local anesthetic toxicity were also recorded. In our study, the sample size was determined using the G*Power software (version 3.1.9.7), referencing a recent similar study evaluating postoperative opioid consumption [ 17 ]. The effect size was set at 0.70, with a significance level of 5% and a power of 80%. Based on these parameters, it was determined that at least 34 patients per group, totaling 68 patients, needed to be included in the study. Study data were analyzed using IBM SPSS Statistics for Windows, version 26.0 (IBM Corp., Armonk, NY, USA). The distribution of continuous variables was assessed using the Kolmogorov–Smirnov test. Quantitative variables were expressed as mean ± standard deviation (SD) for normally distributed data or median with interquartile range (IQR) for non-normally distributed data, while qualitative variables were presented as number and percentage. Comparisons between two independent groups were performed using the Student’s t-test for normally distributed variables and the Mann–Whitney U test for non-normally distributed variables. Categorical variables were compared using Pearson’s chi-square test, as the minimum expected cell count exceeded 5 for all comparisons. Changes in VAS scores over time were analyzed using repeated-measures analysis of variance (RM-ANOVA), including group, time, and group × time interaction effects. Absolute risk differences (RD) with 95% confidence intervals (CI) were calculated for categorical outcomes to provide effect size estimates. A two-sided p-value of < 0.05 was considered statistically significant.

In the OSTAP group, two patients who required conversion to laparotomy, and in the TQL group, two patients with a surgical duration exceeding 120 min, and one patient whose surgery was canceled due to an antibiotic allergy were excluded from the study. Consequently, after excluding five patients, data from 68 patients were analyzed (Fig.  2 ). Fig. 2 Consolidated Standards of Reporting Trials (CONSORT) flow diagram of the study, OSTAP = Oblique subcostal transversus abdominis plane, TQL = Transmuscular quadratus lumborum Consolidated Standards of Reporting Trials (CONSORT) flow diagram of the study, OSTAP = Oblique subcostal transversus abdominis plane, TQL = Transmuscular quadratus lumborum No statistically significant differences were found between the groups in demographic characteristics, type of surgery, anesthesia time, and surgical time (Table  1 ). Table 1 Demographic and intraoperative characteristics of patients Characteristic OSTAP Group ( n  = 34) TQL Group ( n  = 34) p values Age (yrs.) 40.41 ± 9,51 39.53 ± 8.25 0.684 1 ASA PS (I/II) 24 (70.6) / 10 (29.4) 25 (73.5) / 9 (26.5) 0.787 2 Height (cm) 165 (160–168) 162.5 (159–165) 0.054 3 Weight (kg) 60.28 ± 7.50 59.44 ± 5.96 0.611 1 BMI (kg/m 2 ) 22.29 ± 2.24 22.69 ± 1.90 0.429 1 Type of Surgery - TLH + BSO 15 (44.1) 14 (41.2) DIE surgery 8 (23.5) 8 (23.5) Ovarian cyst excision 5 (14.7) 5 (14.7) Bilateral salpingectomy 3 (8.8) 3 (8.8) Myomectomy 2 (5.9) 1 (2.9) Tubal recanalization 1 (2.9) 1 (2.9) Unilateral salpingectomy 0 (0.0) 1 (2.9) Bilateral tubal ligation 0 (0.0) 1 (2.9) Anesthesia time (min) 102.3 ± 26.89 96.09 ± 31.18 0.380 1 Surgical time (min) 90 (70–100) 75 (50–100) 0.140 3 Values are presented as mean ± SD, median (IQR) or number (percentages) ASA PS  American Society of Anesthesiologists physical status, BMI  Body mass index, TLH + BSO  Total laparoscopic hysterectomy + bilateral salpingo-oophorectomy, DIE  Deeply infiltrating endometriosis, OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum 1 Student’s t-test for normally distributed variables 2 Pearson’s chi-square test was used for categorical comparisons, as the minimum expected cell count exceeded 5 for all variables 3 Mann–Whitney U test for non-normally distributed variables Demographic and intraoperative characteristics of patients Values are presented as mean ± SD, median (IQR) or number (percentages) ASA PS  American Society of Anesthesiologists physical status, BMI  Body mass index, TLH + BSO  Total laparoscopic hysterectomy + bilateral salpingo-oophorectomy, DIE  Deeply infiltrating endometriosis, OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum 1 Student’s t-test for normally distributed variables 2 Pearson’s chi-square test was used for categorical comparisons, as the minimum expected cell count exceeded 5 for all variables 3 Mann–Whitney U test for non-normally distributed variables Postoperative tramadol requirement was significantly lower in the TQL group compared with the OSTAP group (RD 29.4%, 95% CI 9.6–49.2; p  = 0.006). Total paracetamol consumption, in patients receiving paracetamol, was significantly lower in the TQL group ( p  = 0.002), whereas total tramadol consumption, in patients receiving tramadol, was similar between the groups. No statistically significant differences were observed between the groups regarding postoperative paracetamol requirement (RD 5.9%, 95% CI − 12.2 to 24.0) and the time to first paracetamol and tramadol requirement (Table  2 ). Table 2 Postoperative analgesic consumption OSTAP Group TQL Group p values Postoperative paracetamol requirement (OSTAP Group n  = 34, TQL Group n  = 34) 29 (85.3) 27 (79.4) 0.525 *1 The time to first paracetamol requirement (hour) (OSTAP Group n  = 29, TQL Group n  = 27) 1 (0.5-2) 1 (0.63-2) 0.946 2 Total paracetamol consumption (mg) (OSTAP Group n  = 29, TQL Group n  = 27) 1000 (1000–1500) 500 (500–1000) 0.002 2 Postoperative tramadol requirement (OSTAP Group n  = 34, TQL Group n  = 34) 14 (41.2) 4 (11.8) 0.006 *1 The time to first tramadol requirement (hour) (OSTAP Group n  = 14, TQL Group n  = 4) 2 (2–3) 1.5 (1-2.75) 0.226 2 Total tramadol consumption (mg) (OSTAP Group n  = 14, TQL Group n  = 4) 60 (57.5-61.25) 55 (50-67.5) 0.565 2 Values are presented as median (IQR) or number (percentages) OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum * Absolute risk differences (RD) with 95% confidence intervals were calculated for postoperative tramadol requirement [RD: 29.4% (95% CI 9.6–49.2)] and paracetamol requirement [RD: 5.9% (95% CI − 12.2 to 24.0)], defined as the difference in proportions between groups (OSTAP − TQL) 1 Pearson’s chi-square test was used for categorical comparisons, as the minimum expected cell count exceeded 5 for all variables, 2 Mann–Whitney U test for non-normally distributed variables Postoperative analgesic consumption Postoperative paracetamol requirement (OSTAP Group n  = 34, TQL Group n  = 34) The time to first paracetamol requirement (hour) (OSTAP Group n  = 29, TQL Group n  = 27) Total paracetamol consumption (mg) (OSTAP Group n  = 29, TQL Group n  = 27) Postoperative tramadol requirement (OSTAP Group n  = 34, TQL Group n  = 34) The time to first tramadol requirement (hour) (OSTAP Group n  = 14, TQL Group n  = 4) Total tramadol consumption (mg) (OSTAP Group n  = 14, TQL Group n  = 4) Values are presented as median (IQR) or number (percentages) OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum * Absolute risk differences (RD) with 95% confidence intervals were calculated for postoperative tramadol requirement [RD: 29.4% (95% CI 9.6–49.2)] and paracetamol requirement [RD: 5.9% (95% CI − 12.2 to 24.0)], defined as the difference in proportions between groups (OSTAP − TQL) 1 Pearson’s chi-square test was used for categorical comparisons, as the minimum expected cell count exceeded 5 for all variables, 2 Mann–Whitney U test for non-normally distributed variables The VAS scores measured at rest showed a significant decrease over time in both groups (time effect, p  < 0.001). No statistically significant group effect was observed for VAS scores at rest, and the pattern of change in VAS scores over time did not differ between the groups (group × time interaction, Table  3 ). Table 3 Changes in VAS scores at rest and during movement over time according to groups VAS scores OSTAP Group ( n  = 34) TQL Group ( n  = 34) VAS scores at rest  0 min 1.8 ± 1.2 1.8 ± 1.2  30 min 2.5 ± 1.7 2.7 ± 1.8  1 h 3.4 ± 2.3 3.2 ± 1.8  2 h 3.4 ± 2.2 2.3 ± 1.3  6 h 2.7 ± 1.8 1.7 ± 1.5  12 h 2.2 ± 1.6 1.5 ± 1.6  18 h 1.8 ± 1.6 1.2 ± 1.5  24 h 1.0 ± 0.7 0.8 ± 1.1 Before discharge 0.9 ± 0.7 0.6 ± 0.8 p values 1 Group 0.061 Time < 0.001 Group x Time 0.112 VAS scores during movement  6 h 3.5 ± 1.9 2.2 ± 1.5  12 h 3.0 ± 1.8 2.2 ± 1.7  18 h 2.5 ± 1.7 1.9 ± 1.7  24 h 1.7 ± 0.9 1.4 ± 1.3 Before discharge 1.7 ± 0.9 1.2 ± 1.0 p values 1 Group 0.009 Time < 0.001 Group x Time 0.152 Values are presented as mean ± SD VAS  Visual Analog Scale, OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum 1 VAS scores were analyzed using repeated-measures ANOVA with group, time, and group × time effects Changes in VAS scores at rest and during movement over time according to groups Values are presented as mean ± SD VAS  Visual Analog Scale, OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum 1 VAS scores were analyzed using repeated-measures ANOVA with group, time, and group × time effects When VAS scores measured during movement were examined, a significant decrease over time was observed in both groups (time effect, p  < 0.001). A statistically significant difference was found between the groups in terms of VAS scores during movement (group effect, p  = 0.009), indicating that the TQL group generally experienced lower pain levels during movement. However, the pattern of change in VAS scores over time did not show a statistically significant difference between the groups (group × time interaction, Table  3 ). There were no statistically significant differences between the groups regarding the total or domain-specific QoR-15 scores preoperatively and 24 h postoperatively (Table  4 ). Table 4 QoR-15 questionnaire total and domain scores OSTAP Group ( n  = 34) TQL Group ( n  = 34) p values Preoperative  QoR-15 total score (0-150) 138 (126-143.5) 137 (129.75-143.25) 0.961 1  QoR-15 domain scores   Pain (0–20) 20 (17.75-20) 20 (18–20) 0.663 1   Physical comfort (0–50) 46 (40–49) 46 (40-48.5) 0.688 1   Physical independence (0–20) 20 (20–20) 20 (20–20) 0.964 1   Psychological support (0–20) 20 (20–20) 20 (20–20) 0.626 1   Emotional state (0–40) 34 (29.75–38.25) 35.5 (30–37) 0.995 1 24 h postoperative  QoR-15 total score (0-150) 131.0 (127.5–138) 134.0 (125.75–140) 0.435 1  QoR-15 domain scores   Pain (0–20) 16.0 (13–18) 17.0 (15.75-19) 0.060 1   Physical comfort (0–50) 45.0 (40–48) 45 (40.75-48) 0.912 1   Physical independence (0–20) 17.5 (15.75-18) 18.0 (16-19.25) 0.281 1   Psychological support (0–20) 20.0 (20–20) 20.0 (20–20) 0.798 1   Emotional state (0–40) 34.5 (32.75–38.5) 36 (32–39) 0.786 1 Values are presented as median (IQR) QoR-15  Quality of Recovery-15, OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum 1 Mann–Whitney U test for non-normally distributed variables QoR-15 questionnaire total and domain scores Values are presented as median (IQR) QoR-15  Quality of Recovery-15, OSTAP  Oblique subcostal transversus abdominis plane, TQL  Transmuscular quadratus lumborum 1 Mann–Whitney U test for non-normally distributed variables There was no statistically significant difference between the groups in the incidence of nausea and vomiting within the first 24 h postoperatively, with only two patients in each group experiencing vomiting once. None of the patients included in the study experienced a block-related complication such as hematoma or infection at the injection site, abdominal organ injury, lower extremity muscle weakness, and local anesthetic toxicity.

Laparoscopic surgery has become an essential technique in modern gynecologic surgery, providing a minimally invasive alternative to open procedures. Although visceral pain is one of the most frequently reported complaints following laparoscopic surgery, various perioperative factors such as incisions for trocar entry, pneumoperitoneum, distention of the anterior abdominal wall, dissection of the pelvic region, and residual intra-abdominal blood may also be the causes of postoperative pain [ 1 , 2 ]. Inadequate pain control negatively impacts quality of life and recovery, prolongs hospital stay, and increases the risk of postoperative complications and chronic pain development [ 3 , 4 ]. Various methods can be implemented to manage postoperative pain in laparoscopic gynecological surgeries, including paracetamol, non-steroidal anti-inflammatory drugs, pregabalin, gabapentin, opioids, local anesthetic infiltration (LAI) at the incision site, and regional anesthesia [ 5 , 6 ]. Considering the adverse effects of analgesic agents, regional anesthesia is gaining increasing prominence in multimodal pain management strategies following laparoscopic surgery [ 7 , 8 ]. The oblique subcostal transversus abdominis plane (OSTAP) block, which was first described by Hebbard et al. [ 9 ], provides analgesia in the dermatomes from T6 to L1 [ 10 ]. The quadratus lumborum (QL) block, initially described by Rafael Blanco [ 11 ], provides an analgesic effect on both the incision site and visceral region by facilitating the spread of local anesthetic from the thoracolumbar fascia to the thoracic paravertebral space [ 12 ]. The transmuscular quadratus lumborum (TQL) block, a variation of the QL block, was described by Børglum et al. [ 13 ] and covers the T4 to L1 dermatomes for analgesia [ 14 ]. This study aimed to investigate the effects of OSTAP and TQL blocks on postoperative analgesia and quality of recovery (QoR) in patients undergoing laparoscopic gynecological surgery. We hypothesized that the TQL block would be superior to the OSTAP block in providing analgesia and reducing tramadol requirement in laparoscopic gynecological surgeries. The primary aim of the study was to compare postoperative tramadol requirement in patients undergoing laparoscopic gynecological surgery. Secondary aims included postoperative paracetamol requirement, time to first paracetamol and tramadol requirement, total paracetamol and tramadol consumption within the first 24 h postoperatively, visual analog scale (VAS) scores at rest and during movement, and the Quality of Recovery-15 (QoR-15) scores preoperatively and 24 h postoperatively.

The present study compared the effect of OSTAP and TQL blocks on postoperative analgesia and QoR in laparoscopic gynecological surgery, addressing an important gap in the existing literature. Previous studies have largely focused on a single surgical procedure and have evaluated pain scores and/or opioid consumption. In contrast, the present study examined a broader range of laparoscopic gynecological procedures with similar abdominal wall involvement, allowing the findings to be interpreted beyond a single surgical procedure. Additionally, not only opioid requirement but also the QoR was assessed using the QoR-15 questionnaire, a patient-centered outcome measure. In this study, postoperative tramadol requirement and total paracetamol consumption, in patients receiving paracetamol, was significantly lower in the TQL group. VAS scores measured at rest and during movement significantly decreased over time in both groups; however, VAS scores during movement were significantly lower in the TQL group. Hebbard et al. [ 9 ] described OSTAP block in their study, where they administered 40–80 ml of local anesthetic, blocking the lateral and anterior branches of the T6–L1 spinal nerves, thereby providing analgesia to the anterior abdominal wall [ 9 , 10 ]. Chen et al. [ 18 ] directed the needle inferolaterally and performed OSTAP block with 20 ml of 0.375% ropivacaine; a cold test 30 min later confirmed complete T7–T12 blockade. This approach provided effective analgesia with a lower volume of anesthetic compared to the technique described by Hebbard et al. [ 9 ]. In present study, similar to studies in the literature, block was administered bilaterally using 20 ml of 0.25% bupivacaine, directing the needle inferolaterally [ 18 – 20 ]. There are only a limited number of studies on the OSTAP block for postoperative analgesia in laparoscopic gynecological surgeries. Toker et al. [ 21 ] indicated in patients undergoing total laparoscopic hysterectomy (TLH) that the OSTAP group had significantly lower VAS scores during coughing and consumed significantly lower amounts of tramadol compared to the control group. Based on the existing data in the literature, the OSTAP block can be considered an effective option for postoperative pain management in laparoscopic gynecological surgery. Although Børglum et al. [ 13 ] reported that the TQL block provides analgesia covering the dermatomes T4 to L1, studies in the literature have not reached a consensus on the precise levels where analgesia is effective. In the cadaver study by Dam et al. [ 14 ], the investigators examined the spread of the TQL block applied at the L4 level and reported that the dye spread over the diaphragm in all cases. In 50% of the cases, the dye spread over the medial and lateral arcuate ligaments, while in 30% it extended via the lateral arcuate ligament into the thoracic paravertebral space. The highest level reached by the dye was at the T9 vertebral level. The anterior branches of the spinal nerves and the thoracic sympathetic chain were dyed, with the dye surrounding the subcostal, iliohypogastric, and ilioinguinal nerves in all cases, while the genitofemoral and lateral femoral cutaneous nerves were dyed to varying degrees. Carline et al. [ 22 ] concluded in their cadaver study that the TQL block consistently blocked the lumbar nerve roots and had the potential to provide analgesia from T10 to L4, making it a reliable option for postoperative analgesia. Considering the existing data, the TQL block appears to be a potentially effective and safe option for postoperative pain management following laparoscopic gynecological surgery. In the study conducted by Huang et al. [ 17 ] to investigate the postoperative analgesic efficacy of TQL and OSTAP blocks in patients undergoing TLH, total morphine consumption within 24 h was significantly lower in the TQL group. In addition, visceral numerical rating scale (NRS) scores at rest and during movement were significantly lower in the TQL group, while no significant difference was observed between the groups regarding incisional NRS scores at rest and during movement. Similarly, in our study, lower opioid requirement and lower movement-related VAS scores were observed in the TQL group. These findings suggest that the effectiveness of the TQL block in providing visceral analgesia may be attributed to its broader blockade, affecting both somatic nerves and sympathetic nerve fibers [ 14 ]. The impact of the TQL block on the sympathetic chain may contribute to visceral pain management, especially in laparoscopic gynecological surgeries, and be associated with a reduced opioid requirement. In contrast, the OSTAP block primarily targets somatic nerves and provides analgesia to the anterior abdominal wall [ 9 ]. Therefore, the OSTAP block emerges as an effective technique for managing incisional pain. However, potential adverse effects during the TQL block procedure should be considered. In their cadaver study comparing the spread of the TQL block administered at the L4 level with the transversus oblique paramedian (TOP) TQL block administered at the L2 level, Dam et al. [ 14 ] demonstrated that if the psoas major muscle is penetrated, the local anesthetic can easily reach the L3 level and the femoral nerve. Kadoya et al. [ 23 ] reported a 13.3% incidence of quadriceps muscle weakness following TQL block performed at the L2 level. This phenomenon was suggested to be associated with the spread of local anesthetic to the lumbar plexus via the PM muscle or its passage into the paravertebral space through the arcuate ligament. The findings of these studies highlight the importance of preserving the PM muscle during the TQL block procedure and underscore the need for careful monitoring of patients following block application. Enhanced Recovery After Surgery (ERAS) protocols aim to optimize postoperative recovery by standardizing perioperative care [ 24 ]. Commonly used clinical outcomes in routine practice, such as length of hospital stay and complication rates, do not adequately reflect how patients experience postoperative recovery. Therefore, patient-centered outcome measures have become increasingly important for providing a multidimensional assessment of postoperative recovery. In the present study, we used the QoR-15 questionnaire to assess patients’ QoR. The QoR-15 is a shortened version of the QoR-40 questionnaire developed by Myles et al. [ 25 ] to assess postoperative recovery from the patient’s perspective. The original QoR-40 includes five dimensions of health status, namely pain, physical comfort, physical independence, psychological support, and emotional state, and consists of 40 questions. However, due to the time-consuming nature of the full version, Stark et al. [ 26 ] introduced the more efficient 15-item QoR-15 as an alternative. The QoR-15 evaluates similar aspects of recovery and has been shown to be a valid, reliable, responsive, and patient-centered outcome measure [ 27 ]. Its practicality makes it well suited for clinical research. The validity and reliability of the Turkish version of the QoR-15 were established by Kara et al. [ 15 ] and Selvi et al. [ 16 ]. In our study, no statistically significant differences were observed between the groups in the total or domain-specific QoR-15 scores preoperatively and 24 h postoperatively. Consistently, Suzuka et al. [ 28 ] compared the OSTAP block and the modified thoracoabdominal nerve block through the perichondrial approach in TLH and reported no statistically significant differences in total QoR-15 scores preoperatively and on postoperative day 1. In our study, in addition to the absence of statistical significance, the absolute between group differences in total QoR-15 scores did not exceed the currently recommended minimal clinically important difference of 6.0 points [ 29 ]. The QoR-15 questionnaire is a subjective assessment tool evaluating postoperative recovery across five dimensions. The lack of both statistical and clinical differences in QoR-15 scores between the two groups suggests that recovery is influenced not only by pain levels but also by the patient’s physical and psychosocial state. The incidence of nausea and vomiting within the first 24 h postoperatively was very low, with only two out of 34 patients in each group experiencing vomiting once. Saleh et al. [ 30 ] adopted a similar approach, where patients received 1 gram IV paracetamol every 8 h postoperatively, and pethidine was used as a rescue analgesic. Compared to the control group, both subcostal TAP and TQL groups had significantly lower pethidine use and incidence of vomiting. We believe the primary factor in keeping nausea and vomiting rates so low was our approach of prioritizing regional anesthesia and paracetamol for pain management while minimizing opioid use as much as possible. Our study has some limitations to acknowledge. First, we excluded patients with a BMI > 25 kg/m² and those with a surgical duration exceeding 120 min. Second, although intravenous sedation was used, the need to perform the blocks in different patient positions may have limited complete patient blinding. Finally, since the patients were monitored only up to 24 h in the postoperative period, we could not assess the long-term effects of the blocks on pain scores and complications.

Patients who received the TQL block in laparoscopic gynecological surgeries had lower tramadol requirement and VAS scores compared to those who received the OSTAP block. However, both blocks provided adequate analgesia, and no significant difference was found in QoR between the two groups. These findings suggest that both TQL and OSTAP blocks could be effective options in multimodal analgesia protocols, with the choice of the block being guided by factors such as the patient characteristics, the anesthesiologist’s experience, and the specific surgical procedure.

Supplementary Material 1. Supplementary Material 1.