Effects of general anesthesia plus ropivacaine transversus abdominis plane block on analgesia and organ protection in colorectal cancer surgery

Abstract

BACKGROUND

The global incidence of colorectal cancer (CRC) is rising annually, with radical resection as its primary curative treatment. Conventional general anesthesia for CRC surgery is frequently complicated by inadequate postoperative analgesia and opioid-related adverse reactions. Although ropivacaine transversus abdominis plane block (TAPB) is a widely used multimodal analgesic technique, its comprehensive effects on perioperative inflammatory stress and organ function in CRC patients remain insufficiently investigated.

AIM

To investigate the effects of general anesthesia + ropivacaine TAPB in patients undergoing radical resection for CRC.

METHODS

This retrospective cohort study analyzed clinical data of patients who underwent radical resection for CRC at Hunan Provincial People’s Hospital between December 2018 and January 2025. Patients who received general anesthesia alone were assigned to the control group, and those who received general anesthesia plus ropivacaine TAPB were assigned to the combination group. Postoperative recovery indices, resting and postoperative state visual analog scale (VAS) scores, and pre- and postoperative inflammatory and liver/kidney function indices were extracted. The incidence of postoperative complications was assessed. Multiple linear regression analysis was performed to identify factors influencing postoperative pain.

RESULTS

Overall, 208 patients were evaluated (control group, n = 85; combination group, n = 123). The combination group experienced shorter times to first flatus, resumption of regular eating, and first defecation, and shorter postoperative hospital stay, and lower VAS scores at 6 hours, 24 hours, and 48 hours postoperatively than controls (all P < 0.05). Compared with controls, the combination group showed lower levels of interleukin-6, white blood cell count, and serum lactate at 24 hours postoperatively (all P < 0.05), and lower levels of alanine aminotransferase, aspartate aminotransferase, serum creatinine, and blood urea nitrogen at 72 hours postoperatively (all P < 0.05). The overall complication rate did not differ (P = 0.150); however, a lower incidence of postoperative nausea and vomiting was observed in the combination group (P = 0.032). Multiple linear regression analysis identified anesthesia regimen (β = -0.816, P < 0.001) and body mass index (β = 0.040, P = 0.024) as independent influencing factors of the VAS score at 24-hour postoperatively.

CONCLUSION

General anesthesia + ropivacaine TAPB for radical resection of CRC provides superior postoperative analgesic effects, effectively reduces inflammatory and stress responses, and is associated with lower postoperative liver and kidney function indices.

Key Words: General anesthesia; Transversus abdominis plane block; Ropivacaine; Radical resection of colorectal cancer; Postoperative analgesia; Inflammatory response

Core Tip: This retrospective study demonstrated that, for patients undergoing radical resection of colorectal cancer, general anesthesia combined with ropivacaine transversus abdominis plane block provides superior postoperative analgesia, reduces inflammatory stress, is associated with favorable postoperative liver and kidney function indices, and accelerates early recovery compared with general anesthesia alone.

INTRODUCTION

The annual incidence of colorectal cancer (CRC) has increased in recent years, posing substantial challenges to global public health, clinical diagnosis, and treatment[1]. Surgical resection remains the core management strategy for radical CRC therapy, with radical resection being a crucial approach[2]. With the widespread application of radical resection for CRC, postoperative analgesic methods have attracted increasing attention.

This procedure typically involves extensive dissection for lymph node clearance and requires a relatively long abdominal incision, resulting in substantial surgical trauma[3,4]. Opioids are commonly used as analgesics to alleviate intraoperative and postoperative pain. However, these medications may give rise to adverse effects, including respiratory depression, nausea, and vomiting, which hinder the surgical process and patient recovery[5,6]. General anesthesia is a frequently adopted method for CRC surgery, but is often associated with issues such as inadequate postoperative analgesia and adverse effects, including nausea and vomiting[7]. Consequently, multimodal analgesia has gradually gained attention as the preferred approach. Transversus abdominis plane block (TAPB) is an emerging postoperative analgesic technique that involves injecting local anesthetics into the fascial plane between the internal oblique and transversus abdominis muscles, thereby blocking the nerves that innervate the anterior abdominal wall and alleviating postoperative pain[8]. When used alone, local anesthetics require high doses, often triggering frequent adverse effects and an insufficient duration of analgesia[9]. Therefore, enhancing the analgesic efficacy of drugs may improve analgesic quality and reduce adverse reactions[10]. Ropivacaine, a long-acting amide local anesthetic, has become an ideal choice for TAPB because of its notable sensory-motor block separation characteristics and relatively low cardiotoxicity[11]. Ropivacaine administration during TAPB has been reported to prolong nerve blockade[12]. However, previous studies have primarily focused on the analgesic efficacy of this technique and short-term improvements in recovery indices. Comprehensive studies on the analgesic and stress-suppressing effects of general anesthesia on liver and kidney function are lacking. Accordingly, this study systematically investigated the perioperative analgesic and stress-suppressing effects of general anesthesia plus ropivacaine TAPB in patients undergoing radical resection for CRC through a retrospective cohort analysis with exploratory observations on postoperative liver and kidney function indices.

MATERIALS AND METHODS

Data sources and study population

This retrospective cohort study analyzed clinical data from 230 patients who underwent radical resection for CRC at Hunan Provincial People’s Hospital between December 2018 and January 2025. The sample size was determined using the feasibility principle and included all eligible cases within the specified study period who met the inclusion and exclusion criteria.

The inclusion criteria were as follows: (1) Patients diagnosed with primary CRC based on pathological examination and treated with radical CRC surgery in accordance with the Chinese Guidelines for Diagnosis and Treatment of Colorectal Cancer (2020 edition)[13]; (2) American Society of Anesthesiologists classification of I-II; (3) Age ≥ 18 years; and (4) Availability of complete and accessible clinical medical records, laboratory test results, and follow-up data.

The exclusion criteria applied consisted of patients: (1) With preoperative severe central nervous system or respiratory diseases that could potentially affect postoperative recovery, extubation, or pain assessment; (2) Severe cardiovascular or cerebrovascular diseases (e.g., unstable angina and severe heart failure) or severe hepatic or renal dysfunction (e.g., Child-Pugh class C) that would render the patient unfit for surgery or anesthesia; (3) With a known history of allergy to ropivacaine or any amide-type local anesthetic; and (4) Those pregnant or lactating.

Based on these criteria, 208 patients with CRC were included in the analysis. Among them, 85 patients who received general anesthesia alone during surgery were assigned to the control group, and 123 patients who received general anesthesia plus ropivacaine TAPB were assigned to the combination group. Allocation to either anesthesia regimen was determined by the preference of the attending anesthesiologist and established clinical routines, without randomization. This study was approved by the Ethics Committee of Hunan Provincial People’s Hospital.

Anesthesia method

All patients underwent routine preoperative fasting. After entering the operating room, vital signs were monitored, and intravenous access was established. In the control group, all patients underwent induction with intravenous injections of midazolam, propofol, sufentanil, or cisatracurium, followed by endotracheal intubation. During surgery, anesthesia was maintained with a continuous infusion of propofol and remifentanil, combined with sevoflurane inhalation, keeping the bispectral index within the range of 40 to 60. Postoperative analgesia was uniformly administered using a patient-controlled intravenous analgesia pump (formula: Sufentanil 2 μg/kg + tropisetron 10 mg, diluted to 100 mL). The parameters were set at a background infusion rate of 2 mL/hour, bolus dose of 2 mL, and a lockout interval of 15 minutes. If the analgesia was inadequate [visual analog scale (VAS) score > 4], tramadol (1 mg/kg) was administered intravenously as a rescue analgesic.

In addition to the general anesthesia protocol used in the control group, ultrasound-guided TAPB was performed using a high-frequency linear array probe (6-13 MHz). With the patient in the supine position, the probe was placed in the mid-axillary line between the costal margin and iliac crest to identify the anatomical layers of the external oblique, internal oblique, and transversus abdominis muscles. The needle was inserted in-plane from the anterior approach, and correct tip placement in the fascial plane between the internal oblique and transversus abdominis muscles was confirmed by hydrodissection with 2-3 mL of normal saline. Subsequently, 40 mL of 0.375% ropivacaine (20 mL per side) was injected bilaterally under real-time ultrasound visualization, and the observed linear spread of the local anesthetic confirmed proper block placement.

Outcome measures

The primary outcome was the postoperative pain score. Resting-state VAS scores at 6 hours, 24 hours, and 48 hours postoperatively were extracted from the patients’ medical records. The VAS score ranged from 0 (no pain) to 10 (severe pain), with higher scores indicating more intense pain[14]. The following secondary outcome measures were also assessed: (1) Perioperative recovery indices: Time to first flatus, time to resumption of regular eating, time to first defecation, and postoperative hospital stay, which were compared between the two groups; (2) Inflammatory and stress indices, white blood cell (WBC) count, interleukin (IL)-6 levels, and serum lactate levels were compared between the two groups before surgery and 24 hours postoperatively. Fasting peripheral venous blood samples (5 mL) were collected from patients in the morning before surgery and 24 hours postoperatively. WBC count was measured using an automated hematology analyzer, serum IL-6 levels were determined using an enzyme-linked immunosorbent assay, and serum lactate levels were measured using a blood gas analyzer; (3) Organ function indices: The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum creatinine (Cr), and blood urea nitrogen (BUN) were compared between the two groups before surgery and at 24 hours and 72 hours postoperatively. Blood samples (5 mL of fasting venous blood) were collected from the patients in the morning before surgery and at 24 hours and 72 hours postoperatively. ALT and AST levels were measured using an enzymatic rate method on an automatic biochemical analyzer, and serum Cr and BUN levels were measured using a colorimetric method on the same analyzer; and (4) Safety indices: The incidence of adverse events from surgery to discharge, including postoperative nausea and vomiting, respiratory depression, delayed recovery, postoperative delirium, and urinary retention, was compared between the two groups. Complications were identified through a systematic review of electronic medical records, nursing and anesthesia records, and physician progress notes. All events were independently reviewed by two investigators, and discrepancies were resolved by consensus. Overall complication rates were also calculated. A multiple linear regression analysis was performed to identify factors influencing postoperative pain and to identify factors associated with the severity of postoperative pain. The multiple linear regression model was constructed using the 24-hour postoperative VAS score as the dependent variable.

Statistical analysis

Statistical analyses were performed using SPSS (version 20.0; IBM Corp., Armonk, NY, United States), and graph plotting was performed using GraphPad Prism 7 (GraphPad Software, San Diego, CA, United States). According to the Shapiro-Wilk test, all measurement data in this study followed a normal distribution and were expressed as mean ± SD. Group comparisons were performed using t-tests. Categorical data were presented as n (%), with group comparisons conducted using the χ² test or Fisher’s exact test. Repeatedly measured continuous data were analyzed using repeated-measures analysis of variance for overall comparison. Pairwise comparisons were performed when significant interaction effects were observed. Multiple linear regression analysis was conducted to identify independent factors associated with postoperative pain. All statistical tests were two-sided, and a P-value < 0.05 indicates a notable difference.

RESULTS

Clinical baseline data

The combination group (n = 123) and control group (n = 85) did not show significant differences in baseline characteristics, including age, sex, body mass index, tumor tumor-node-metastasis stage, American Society of Anesthesiologists classification, family history of CRC, and place of residence (all P > 0.05) (Table 1).

Table 1 Baseline data of included patients, n (%)/mean ± SD.

Factors	Control group (n = 85)	Combination group (n = 123)	χ2/t	P value
Age (year)	59.95 ± 9.08	57.74 ± 8.28	1.820	0.070
Sex			0.160	0.689
Male	48 (56.47)	66 (53.66)
Female	37 (43.53)	57 (46.34)
BMI (kg/m2)	21.67 ± 2.00	21.54 ± 2.04	0.437	0.663
TNM stage			0.088	0.767
Stage II	46 (54.12)	64 (52.03)
Stage III	39 (45.88)	59 (47.97)
ASA classification			0.141	0.707
Class I	41 (48.24)	55 (44.72)
Class II	44 (51.76)	68 (55.28)
Family history of CRC			0.074	0.785
Yes	8 (9.41)	13 (10.57)
No	77 (90.59)	110 (89.43)
Place of residence			0.703	0.402
Rural areas	49 (57.65)	78 (63.41)
Urban areas	36 (42.35)	45 (36.59)

BMI: Body mass index; TNM: Tumor-node-metastasis; ASA: American Society of Anesthesiologists; CRC: Colorectal cancer.

Postoperative recovery indices

The combination group experienced significantly earlier time to first flatus (30.69 ± 7.51 hours vs 65.55 ± 7.94 hours), time to resumption of regular eating (38.56 ± 9.89 hours vs 73.85 ± 11.52 hours), time to first defecation (80.37 ± 5.24 hours vs 87.36 ± 6.41 hours), and postoperative hospital stay (8.86 ± 0.94 days vs 10.85 ± 1.17 days) than the control group (all P < 0.05, Figure 1).

Figure 1 Comparison of postoperative recovery indices. A: Time to first flatus; B: Time to resumption of regular diet; C: Time to first defecation; D: Hospital stay. ^dP < 0.0001.

Postoperative pain

According to the postoperative pain assessment results, at 6 hours post-surgery, the VAS scores were 2.31 ± 0.40 points in the combination group and 3.87 ± 0.21 points in the control group. At 24 hours post-surgery, the VAS scores were 1.11 ± 0.22 points in the combination group and 2.67 ± 0.18 points in the control group. At 48 hours post-surgery, the VAS scores were 0.88 ± 0.14 points in the combination group and 1.81 ± 0.23 points in the control group. The combination group showed notably lower VAS scores than the control group at all time points (all P < 0.001; Figure 2).

Figure 2 Comparison of visual analog scale scores between the two groups. A: 6 hours; B: 24 hours; C: 48 hours. ^dP < 0.0001. VAS: Visual analog scale.

Inflammatory and stress indices

Regarding inflammatory markers, no significant inter-group difference was observed in preoperative IL-6 levels (control group: 20.80 ± 5.45 pg/mL; combination group: 20.06 ± 4.00 pg/mL, P > 0.05); at 24 hours post-surgery, the combination group showed notably lower IL-6 levels (249.41 ± 23.60 pg/mL) than the control group (298.59 ± 28.81 pg/mL) (P < 0.05). The preoperative WBC counts were comparable between the two groups [control group: (5.10 ± 0.38) × 10⁹/L; combination group: (5.12 ± 0.34) × 10⁹/L, P > 0.05]. Although both groups showed an increase in WBC at 24 hours postoperatively, the combination group had significantly lower WBC levels [(10.03 ± 1.87) × 10⁹/L] than the control group [(11.49 ± 1.70) × 10⁹/L] (P < 0.05). In terms of metabolic stress indices, no significant inter-group difference was observed in preoperative serum lactate levels (control group: 1.10 ± 0.20 mmol/L; combination group: 1.05 ± 0.20 mmol/L, P > 0.05); at 24 hours post-surgery, the combination group had notably lower lactate levels (2.04 ± 0.41 mmol/L) than the control group (2.83 ± 0.41 mmol/L) (P < 0.05). The details can be seen in Figure 3.

Figure 3 Comparison of pre- and post-operative inflammatory and stress indices. A: Interleukin-6; B: White blood cell; C: Lactate. ^dP < 0.0001. NS: Not significant; IL-6: Interleukin-6; WBC: White blood cell.

Liver and kidney function indices

In terms of liver and kidney function, no significant differences were found between the two groups in the levels of ALT, AST, serum Cr, and BUN before surgery and at 24 hours post-surgery (all P > 0.05). By 72 hours post-surgery, the combination group demonstrated advantages in all measured indices: Its ALT (37.63 ± 5.49 U/L), AST (46.37 ± 8.86 U/L), Cr (90.45 ± 12.40 μmol/L), and BUN levels (7.36 ± 1.53 mmol/L) were significantly lower than those of the control group (43.43 ± 5.07 U/L, 49.33 ± 6.89 U/L, 95.58 ± 11.44 μmol/L, and 7.94 ± 1.59 mmol/L, respectively) (all P < 0.05) (Figure 4).

Figure 4 Comparison of pre- and post-operative liver and kidney function indices. A: Alanine aminotransferase; B: Aspartate aminotransferase; C: Serum creatinine; D: Blood urea nitrogen. ^aP < 0.05; ^bP < 0.01; ^dP < 0.0001. NS: Not significant; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; Cr: Creatinine; BUN: Blood urea nitrogen.

Postoperative complications

No significant difference was observed in the overall incidence of postoperative complications (combination group, 9.76% vs control group, 16.47%; P = 0.150). However, the combination group had a significantly lower incidence of postoperative nausea and vomiting than the control group (3.25% vs 10.59%, P = 0.032). The details are presented in Table 2.

Table 2 Comparison of complications between the two groups, n (%).

	Control group (n = 85)	Combination group (n = 123)	χ2	P value
Nausea and vomiting	9 (10.59)	4 (3.25)	-	0.0321
Respiratory depression	0 (0.00)	0 (0.00)	-	-
Delayed recovery	0 (0.00)	4 (3.25)	-	0.0931
Postoperative delirium	0 (0.00)	0 (0.00)	-	-
Urinary retention	6 (7.06)	4 (3.25)	1.592	0.207
Overall complications	14 (16.47)	12 (9.76)	2.072	0.150

¹Owing to expected frequencies of < 5, Fisher’s exact test was used to calculate the P-value.

TAPB-related adverse events

In the combination group, no cases of local hematoma, infection, local anesthetic systemic toxicity, peritoneal puncture, or bowel injury were identified based on chart review. Regarding the four patients who experienced delayed recovery (3.25% vs 0% in the control group, P = 0.093), a descriptive review revealed no evidence of intraoperative complications, prolonged surgical time, or documented local anesthetic toxicity. All four patients recovered uneventfully with extended monitoring, and no specific intervention was required.

Multiple linear regression analysis of factors influencing overall postoperative pain

The variables for the regression model were selected based on their clinical relevance and previous literature. To avoid overfitting, other clinically relevant variables (e.g., surgical duration and intraoperative opioid dosage) were not included because of the limited sample size. To identify independent factors associated with overall postoperative pain, multiple linear regression analysis was conducted with the VAS score at 24 hours post-surgery as the dependent variable. The results showed that anesthesia regimen (β = -0.816, P < 0.001) and body mass index (β = 0.040, P = 0.024) were independent factors influencing postoperative pain (both P < 0.05) (Table 3).

Table 3 Multiple linear regression analysis of factors influencing visual analog scale score at 24 hours post-operatively.

	Unstandardized coefficient (β)	SE	Standardized coefficient (β)	t value	P value
Constant	2.487	0.274	-	9.072	< 0.001
Anesthesia regimen	-1.633	0.077	-0.816	-21.293	< 0.001
Age (years)	0.003	0.002	0.034	1.876	0.062
BMI (kg/m2)	0.016	0.007	0.040	2.266	0.024
Time of first flatus (hours)	-0.001	0.002	-0.029	-0.655	0.513
IL-6 (pg/mL)	-0.001	0.001	-0.039	-1.647	0.101

BMI: Body mass index; IL-6: Interleukin-1.

DISCUSSION

Radical resection is a common surgical procedure for CRC[15], and different anesthesia methods influence the anesthetic efficacy and analgesic outcomes[16,17]. This study analyzed 208 patients who underwent radical CRC resection to compare the clinical effects of general anesthesia alone with those of general anesthesia combined with ropivacaine TAPB. The results demonstrated that the addition of ropivacaine TAPB not only provided superior postoperative analgesia and effectively alleviated perioperative inflammatory and stress responses, but also shortened hospital stay. Furthermore, this combined approach exhibited potential organ-protective effects in the liver and kidneys and reduced the incidence of postoperative nausea and vomiting.

Regarding analgesia, the combination group showed notably lower VAS scores at 6 hours, 24 hours, and 48 hours postoperatively than the control group. This finding is consistent with the results reported by Zhang et al[18], who confirmed that patients receiving ropivacaine TAPB had notably lower VAS scores in the early postoperative period than those in the control group. The superior analgesic effects of general anesthesia with ropivacaine TAPB may be attributed to the following mechanism: TAPB precisely blocks the anterior branches of the T7-L1 spinal nerves innervating the anterior abdominal wall, thereby interrupting the transmission of surgical traumatic stimuli to the central nervous system[19]. This process is a critical component of preemptive and multimodal analgesia. This regional nerve blockade alleviates pain at its source and reduces the need for systemic opioids[20]. Conversely, general anesthesia alone relies primarily on opioids for analgesia. Although opioids exert central analgesic effects, they simultaneously inhibit gastrointestinal motility and may induce adverse effects such as nausea and vomiting, thereby hindering postoperative recovery[21,22]. In the present study, the significantly reduced incidence of postoperative nausea and vomiting in the combination group was a direct benefit of the decreased use of opioids. Our multiple linear regression analysis further confirmed that the anesthesia regimen (general anesthesia plus TAPB) was the strongest independent factor influencing pain 24 hours post-surgery. Therefore, the value of combining TAPB lies not only in its analgesic effects per se but also in its opioid-sparing effect, which clears the path for enhanced patient recovery. Notably, the observed difference in 24-hour VAS scores exceeded the minimal clinically important difference for postoperative pain, supporting the clinical relevance of this analgesic benefit.

Regarding systemic regulatory effects, the combination group demonstrated notably lower levels of inflammatory markers (IL-6 and WBC) and metabolic stress indices (serum lactate) at 24 hours postoperatively than the control group. These results suggest a systemic physiological regulatory effect of TAPB. Surgical trauma and postoperative pain, as potent stressors, can activate the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, triggering the release of large amounts of key pro-inflammatory cytokines such as IL-6[23]. In this study, the smaller increase in postoperative IL-6 levels in the combination group may be attributed to the regional analgesic effect of the TAPB, which blocks the transmission of nociceptive stimuli to the central nervous system, thereby reducing the intensity of neuroendocrine stress and suppressing excessive inflammatory cascade reactions[24]. The lower lactate levels in the combination group indirectly reflected a more stable internal physiological environment. Furthermore, the combination group demonstrated significant advantages in terms of time to first flatus, resumption of regular eating, time to first defecation, and length of postoperative hospital stay. The mechanisms underlying postoperative gastrointestinal inhibition are complex and involve surgical manipulation, sympathetic excitation, inflammatory responses, and opioid effects of opioids[25]. Effective analgesia promotes early mobilization, reduces opioid-induced ileus, and mitigates inflammation-induced intestinal suppression, thereby synergistically facilitating the early recovery of gastrointestinal function and shortening the hospital stay[26]. This recovery-enhancing effect is consistent with the results of previous studies. For example, in a controlled trial, Hou et al[27] reported that patients undergoing laparoscopic CRC surgery with TAPB had notably lower VAS pain scores 24 hours postoperatively and shorter hospital stays. The median postoperative hospital stay in the TAPB group was 8 days, which aligns with the trend observed in the combination group in this study.

Regarding postoperative liver and kidney function indices, the combination group showed significantly lower ALT, AST, Cr, and BUN levels at 72 hours postoperatively than the control group. However, the absolute differences between groups were modest (e.g., ALT difference ~6 U/L, Cr difference ~5 μmol/L), and all mean values remained within normal clinical reference ranges. Therefore, the clinical significance of these biochemical findings remains uncertain. Several mechanisms may theoretically contribute to these differences, including improved tissue perfusion from effective analgesia, suppression of systemic inflammatory responses, and reduced opioid exposure[28]. Nevertheless, this retrospective study did not include direct measurements such as hepatic or renal blood flow, oxidative stress markers, or tissue perfusion assessments; consequently, the underlying mechanism cannot be definitively attributed to organ protection. Nonetheless, these findings should be interpreted as hypothesis-generating rather than confirmatory.

No TAPB-specific complications (e.g., local hematoma, infection, local anesthetic systemic toxicity, peritoneal puncture, or bowel injury) were observed. Delayed recovery occurred in four patients in the combination group. Although the etiology remains unclear, potential contributing factors may include individual variability in local anesthetic absorption or metabolism. Notably, none of the patients required intervention beyond extended monitoring, and all recovered uneventfully. This observation warrants further investigation in larger prospective studies.

However, this study had some limitations that should be acknowledged. First, because this was a retrospective cohort study with non-randomized allocation, causal inference was not possible, and confounding by indication could not be excluded. Second, modest absolute differences in liver and kidney function indices, all within normal ranges, render the clinical significance uncertain, and direct evidence of organ protection is lacking. Third, this study lacked follow-up data on long-term outcomes. Fourth, this study may have been underpowered to detect rare TAPB-related adverse events, and the four patients with delayed recovery lacked pharmacokinetic data. Therefore, future large-scale, multicenter, prospective, randomized controlled trials are warranted. Future studies should also extend the observation period to include pain scores at rest and with movement beyond 72 hours to assess the duration of analgesic benefit and the potential for rebound pain.

CONCLUSION

In summary, for patients undergoing radical CRC resection, general anesthesia plus ropivacaine TAPB represents an effective and safe perioperative management strategy. This approach provides excellent and sustained postoperative analgesia, alleviates systemic stress and inflammatory responses, and promotes the recovery of gastrointestinal functions. Fortunately, favorable postoperative liver and kidney function indices were observed, although their clinical significance warrants further investigation.