Inguinal hernia is one of the most common surgical disorders encountered worldwide and represents a major proportion of the workload in general surgical practice. It is defined as the protrusion of abdominal contents through a weakness or defect in the inguinal region of the abdominal wall. The lifetime risk of developing an inguinal hernia has been estimated to be approximately 27% in men and 3% in women, making it one of the most frequently performed elective surgical procedures globally as well as in India (1). In the Indian healthcare setting, inguinal hernia repair constitutes a substantial number of surgeries performed in district hospitals, teaching institutions, and tertiary care centers. The standard treatment for inguinal hernia is surgical repair, either through conventional open hernioplasty or laparoscopic techniques. Open tension-free mesh hernioplasty remains the most commonly performed procedure in India because of its simplicity, cost-effectiveness, and applicability in resource-limited settings (2). Successful surgical outcomes depend not only on the surgical technique but also on the choice of anaesthesia, which significantly influences intraoperative conditions, postoperative recovery, patient satisfaction, and complication rates. Anaesthesia for inguinal hernioplasty can be administered using general anaesthesia, regional anaesthesia, or local anaesthesia. Among these, regional anaesthesia has gained considerable popularity because it provides effective intraoperative analgesia, minimizes airway manipulation, decreases stress response, facilitates early postoperative recovery, and reduces the incidence of postoperative nausea and vomiting (3). Furthermore, regional anaesthesia is particularly advantageous in elderly patients and those with associated comorbidities, where avoidance of general anaesthesia may reduce perioperative risks. Spinal anaesthesia and epidural anaesthesia are the two most commonly employed regional anaesthetic techniques for lower abdominal surgeries, including inguinal hernioplasty. Both techniques provide excellent surgical anaesthesia; however, they differ considerably in their pharmacological characteristics, technical aspects, haemodynamic effects, duration of action, and postoperative analgesic benefits (4). Spinal anaesthesia involves the administration of local anaesthetic agents into the subarachnoid space, resulting in rapid onset of sensory, motor, and sympathetic blockade. Since its introduction by August Bier in 1898, spinal anaesthesia has become one of the most widely practiced regional anaesthetic techniques worldwide. It is relatively easy to perform, requires minimal drug dosage, produces dense neural blockade, and provides excellent operating conditions for lower abdominal and lower limb surgeries (5). In India, spinal anaesthesia is frequently preferred for inguinal hernia repair because of its simplicity, reliability, rapid onset, and cost-effectiveness. Despite its advantages, spinal anaesthesia is associated with several limitations. Sudden sympathetic blockade may lead to hypotension and bradycardia, particularly in elderly patients or those with compromised cardiovascular reserve. Other complications include post-dural puncture headache, urinary retention, nausea, vomiting, and transient neurological symptoms (6). These adverse effects may occasionally prolong hospital stay and affect patient satisfaction. Epidural anaesthesia, on the other hand, involves the injection of local anaesthetic agents into the epidural space, producing segmental blockade of spinal nerves. Unlike spinal anaesthesia, epidural blockade develops gradually, allowing better control over the extent and intensity of anaesthesia. An important advantage of epidural anaesthesia is the ability to insert a catheter into the epidural space, which facilitates continuous administration of anaesthetic and analgesic agents during and after surgery (7). Consequently, epidural anaesthesia provides superior postoperative pain control and may reduce the requirement for systemic analgesics. Haemodynamic stability is another important advantage of epidural anaesthesia. Because sympathetic blockade develops gradually, the incidence of severe hypotension is generally lower than that observed with spinal anaesthesia. This characteristic makes epidural anaesthesia particularly useful in patients with cardiovascular disease or in those expected to undergo prolonged surgical procedures (8). However, epidural anaesthesia has certain disadvantages, including slower onset of action, greater technical complexity, higher drug requirements, occasional patchy block, and increased procedure time. Several investigators have compared spinal and epidural anaesthesia for lower abdominal surgeries. However, the results remain inconsistent because of variations in study populations, anaesthetic techniques, local anaesthetic agents, and outcome measures. Some studies have reported superior operating conditions and faster onset with spinal anaesthesia, whereas others have emphasized the benefits of epidural anaesthesia in terms of haemodynamic stability and prolonged postoperative analgesia (9,10). In the Indian context, the choice between spinal and epidural anaesthesia assumes particular significance because of the high volume of inguinal hernia surgeries performed annually and the need for cost-effective perioperative care. Factors such as patient demographics, resource availability, surgical duration, postoperative pain management, and institutional preferences often influence the selection of anaesthetic technique. Despite widespread use of both methods, there remains a need for further comparative evaluation to identify the most appropriate regional anaesthetic approach for patients undergoing inguinal hernioplasty. Postoperative pain management is a major determinant of patient recovery and satisfaction following hernia surgery. Inadequately controlled pain can delay mobilization, increase hospital stay, impair respiratory function, and negatively affect quality of life. Epidural anaesthesia has been shown to provide prolonged analgesia due to the possibility of continuous catheter-based administration, whereas spinal anaesthesia generally offers a limited duration of pain relief (11). Therefore, comparative assessment of postoperative analgesic efficacy remains clinically relevant. Another important consideration is perioperative haemodynamic stability. Inguinal hernia repair is commonly performed in elderly patients who may have coexisting hypertension, diabetes mellitus, ischemic heart disease, or chronic pulmonary disorders. Maintaining stable cardiovascular parameters during surgery is essential for minimizing perioperative morbidity. Regional anaesthetic techniques differ in their effects on sympathetic nervous system activity, making comparison of haemodynamic changes an important component of clinical evaluation (12). The present prospective study was therefore undertaken to compare spinal anaesthesia and epidural anaesthesia in patients undergoing elective inguinal hernioplasty. The study aims to evaluate and compare onset of sensory and motor blockade, haemodynamic changes, duration of postoperative analgesia, intraoperative conditions, and perioperative complications associated with both techniques. The findings of this study may help anaesthesiologists and surgeons select the most appropriate anaesthetic modality for inguinal hernia repair, thereby improving patient outcomes and perioperative care. Aim To compare spinal anaesthesia and epidural anaesthesia in patients undergoing elective inguinal hernioplasty.

Study Design The present study was designed as a hospital-based prospective, randomized, comparative observational study conducted to evaluate and compare the efficacy and safety of spinal anaesthesia and epidural anaesthesia in patients undergoing elective inguinal hernioplasty. Study Setting The study was carried out in the Department of Anaesthesiology in collaboration with the Department of General Surgery at a tertiary care teaching hospital in India. Study Duration The study was conducted over a period of 12 months from October 2019 to September 2020. Ethical Considerations Prior approval for the study was obtained from the Institutional Ethics Committee (IEC) before commencement of the study. • Ethical Clearance Number: IEC/2020/ANES/015 • Written informed consent was obtained from all patients participating in the study. • The study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. Study Population The study included adult patients scheduled for elective open inguinal hernioplasty under regional anaesthesia. Sample Size A total of 100 patients were enrolled in the study. The sample size was calculated based on previous studies comparing spinal and epidural anaesthesia with regard to onset of block and postoperative analgesia. Assuming a confidence level of 95%, power of 80%, and anticipated difference of 20% between groups, a minimum sample size of 45 patients per group was required. To compensate for possible dropouts, 50 patients were included in each group. Sampling Technique Patients fulfilling the inclusion criteria were recruited consecutively and randomized into two equal groups using a computer-generated randomization table. Group Allocation • Group S (Spinal Anaesthesia): 50 patients • Group E (Epidural Anaesthesia): 50 patients Allocation concealment was maintained using sealed opaque envelopes. Inclusion Criteria Patients fulfilling all of the following criteria were included: 1. Age between 18 and 65 years. 2. Either gender. 3. American Society of Anesthesiologists (ASA) Physical Status Grade I and II. 4. Patients scheduled for elective unilateral open inguinal hernioplasty. 5. Patients willing to participate and provide informed consent. Exclusion Criteria Patients with any of the following conditions were excluded: 1. Refusal for regional anaesthesia. 2. Known allergy to local anaesthetic agents. 3. Coagulopathy or bleeding disorders. 4. Anticoagulant therapy. 5. Infection at the site of needle insertion. 6. Severe cardiovascular disease. 7. Neurological disorders. 8. Spinal deformities. 9. Morbid obesity (BMI >35 kg/m²). 10. ASA Grade III and IV patients. 11. Recurrent or complicated inguinal hernia. Anaesthetic Technique Group S Patients received spinal anaesthesia with: • 3 ml of 0.5% Hyperbaric Bupivacaine • L3-L4 interspace • 25G Quincke spinal needle Group E Patients received epidural anaesthesia with: • 15 ml of 0.5% Bupivacaine • L2-L3 interspace • Epidural catheter placement Parameters Observed Heart rate, Systolic blood pressure, Diastolic blood pressure, Mean arterial pressure, Onset of sensory block, Onset of motor block, Duration of surgery, Duration of analgesia, Complications Statistical Analysis Data obtained from the study were entered into Microsoft Excel and analysed using Statistical Package for Social Sciences (SPSS) software version 25.0.

Table 1: Demographic Profile of Study Participants Parameter Group S (Spinal Anaesthesia) (n=50) Group E (Epidural Anaesthesia) (n=50) p-value Age (years) 45.2 ± 11.4 46.8 ± 10.6 0.462 Weight (kg) 64.5 ± 8.1 65.7 ± 7.9 0.447 Height (cm) 165.4 ± 6.2 166.1 ± 5.8 0.563 BMI (kg/m²) 23.6 ± 2.8 23.9 ± 2.5 0.587 Male 48 (96%) 47 (94%) 0.645 Female 2 (4%) 3 (6%) 0.645 ASA Grade I 32 (64%) 30 (60%) 0.681 ASA Grade II 18 (36%) 20 (40%) 0.681 A total of 100 patients were included in the study, with 50 patients each in the spinal anaesthesia (Group S) and epidural anaesthesia (Group E) groups. The mean age of patients in Group S was 45.2 ± 11.4 years compared to 46.8 ± 10.6 years in Group E. The difference was statistically insignificant (p > 0.05), indicating comparable age distribution. The mean body weight was 64.5 ± 8.1 kg in Group S and 65.7 ± 7.9 kg in Group E, while the mean BMI was 23.6 ± 2.8 kg/m² and 23.9 ± 2.5 kg/m² respectively. No statistically significant differences were observed between the groups regarding anthropometric characteristics. The majority of patients were males, accounting for 96% in Group S and 94% in Group E, reflecting the higher prevalence of inguinal hernia among men. Distribution of ASA physical status grades was also comparable between the groups, with no statistically significant difference (p > 0.05). Thus, both groups were demographically comparable and suitable for outcome comparison. Table 2: Onset of Sensory and Motor Block Parameter Group S (Spinal Anaesthesia) (n=50) Group E (Epidural Anaesthesia) (n=50) t-value p-value Onset of Sensory Block (minutes) 4.8 ± 1.2 13.6 ± 2.5 22.45 <0.001 Onset of Motor Block (minutes) 6.2 ± 1.5 18.4 ± 3.1 24.18 <0.001 Table 2 A: Distribution of Onset of Sensory Block Sensory Block Onset (minutes) Group S (n=50) Group E (n=50) 0–5 38 (76%) 0 (0%) 6–10 12 (24%) 6 (12%) 11–15 0 (0%) 26 (52%) 16–20 0 (0%) 18 (36%) Table 2 B: Distribution of Onset of Motor Block Motor Block Onset (minutes) Group S (n=50) Group E (n=50) 0–5 18 (36%) 0 (0%) 6–10 32 (64%) 0 (0%) 11–15 0 (0%) 12 (24%) 16–20 0 (0%) 28 (56%) >20 0 (0%) 10 (20%) The mean onset time of sensory blockade in Group S was 4.8 ± 1.2 minutes, whereas in Group E it was 13.6 ± 2.5 minutes. The difference was found to be highly statistically significant (p < 0.001). Most patients (76%) in the spinal anaesthesia group achieved adequate sensory blockade within 5 minutes, while the majority of patients in the epidural group required 11–15 minutes to attain a comparable sensory level. Similarly, the mean onset time of motor blockade was significantly shorter in Group S (6.2 ± 1.5 minutes) compared to Group E (18.4 ± 3.1 minutes). The difference was highly significant statistically (p < 0.001). All patients receiving spinal anaesthesia developed complete motor blockade within 10 minutes, whereas most patients in the epidural group required 16–20 minutes. The findings indicate that spinal anaesthesia produces a significantly faster onset of both sensory and motor blockade compared to epidural anaesthesia. This rapid onset provides earlier surgical readiness and contributes to reduced anaesthesia preparation time. Epidural anaesthesia, although slower in onset, still achieved adequate surgical anaesthesia in all patients and provided satisfactory operating conditions. Table 3: Comparison of Haemodynamic Changes Between Groups Parameter Group S (Spinal Anaesthesia) (n=50) Group E (Epidural Anaesthesia) (n=50) p-value Baseline Heart Rate (beats/min) 82.4 ± 8.6 81.8 ± 7.9 0.721 Lowest Heart Rate Recorded (beats/min) 71.8 ± 7.2 76.5 ± 7.1 0.002* Baseline SBP (mmHg) 126.8 ± 10.4 127.6 ± 9.8 0.689 Lowest SBP Recorded (mmHg) 108.8 ± 8.2 118.5 ± 8.4 <0.001* Baseline DBP (mmHg) 79.2 ± 7.1 80.1 ± 6.8 0.517 Lowest DBP Recorded (mmHg) 67.5 ± 5.6 74.6 ± 5.8 <0.001* Baseline MAP (mmHg) 95.1 ± 6.8 95.9 ± 6.4 0.553 Lowest MAP Recorded (mmHg) 81.3 ± 5.1 89.2 ± 5.2 <0.001* Hypotension (%) 12 (24%) 5 (10%) 0.041* Bradycardia (%) 6 (12%) 2 (4%) 0.14 *Statistically Significant (p < 0.05) "Patients receiving epidural anaesthesia demonstrated significantly better haemodynamic stability than those receiving spinal anaesthesia. The incidence of hypotension was significantly higher in the spinal group (24%) compared with the epidural group (10%) (p = 0.041). Mean reductions in systolic blood pressure, diastolic blood pressure, and mean arterial pressure were also significantly greater in Group S, suggesting a higher degree of sympathetic blockade associated with spinal anaesthesia." Table 4: Comparison of Duration of Analgesia Between Study Groups Parameter Group S (Spinal Anaesthesia) (n=50) Group E (Epidural Anaesthesia) (n=50) t-value p-value Duration of Analgesia (minutes) 180 ± 35 320 ± 45 17.42 <0.001* Time to First Rescue Analgesic (minutes) 185 ± 38 325 ± 48 16.98 <0.001* Patients Requiring Rescue Analgesia within 4 hours 32 (64%) 8 (16%) — <0.001* *Statistically Significant The duration of postoperative analgesia was significantly longer in the epidural anaesthesia group (320 ± 45 minutes) compared to the spinal anaesthesia group (180 ± 35 minutes), with a statistically significant difference (p < 0.001). Epidural anaesthesia also delayed the requirement of first rescue analgesic and reduced overall postoperative analgesic demand." Table 5: Comparison of Postoperative Complications Between Groups Complication Group S (Spinal Anaesthesia) (n=50) Group E (Epidural Anaesthesia) (n=50) p-value Nausea & Vomiting 6 (12%) 4 (8%) 0.514 Urinary Retention 5 (10%) 2 (4%) 0.24 Post-dural Puncture Headache (PDPH) 3 (6%) 0 (0%) 0.075 Backache 1 (2%) 3 (6%) 0.307 Hypotension-related symptoms 8 (16%) 3 (6%) 0.108 Total Patients with Any Complication 18 (36%) 10 (20%) 0.074 "The incidence of postoperative complications was higher in the spinal anaesthesia group (36%) compared to the epidural anaesthesia group (20%), although the difference was not statistically significant (p > 0.05). Post-dural puncture headache occurred only in the spinal group, whereas backache was slightly more common in the epidural group. Both techniques were found to be safe with minimal and manageable complications."

The present prospective comparative study was conducted to evaluate and compare spinal anaesthesia and epidural anaesthesia in patients undergoing elective inguinal hernioplasty with respect to onset of blockade, haemodynamic stability, duration of postoperative analgesia, and complications. In India, inguinal hernia repair is one of the most frequently performed general surgical procedures, and selection of an appropriate anaesthetic technique plays a key role in optimizing perioperative outcomes, patient satisfaction, and resource utilization. In the present study, both groups were comparable with respect to age, gender distribution, body weight, BMI, and ASA physical status. The majority of patients were males, reflecting the higher incidence of inguinal hernia in males due to anatomical predisposition and occupational strain. Similar observations have been reported by Burcharth et al., who documented a male preponderance in groin hernia cases worldwide (1). Comparable baseline characteristics ensured that intergroup differences in outcomes were attributable to the anaesthetic technique rather than confounding variables. The onset of sensory and motor block was significantly faster in the spinal anaesthesia group compared to the epidural anaesthesia group. In the present study, the mean onset of sensory block in Group S was 4.8 ± 1.2 minutes versus 13.6 ± 2.5 minutes in Group E (p < 0.001). Similarly, motor block onset was also significantly faster in the spinal group. This finding is consistent with the pharmacological basis of spinal anaesthesia, where local anaesthetic is directly deposited in the cerebrospinal fluid, resulting in rapid diffusion to nerve roots and immediate neural blockade. In contrast, epidural anaesthesia requires diffusion of drug across the dura mater, resulting in slower onset. Similar findings were reported by Gupta et al., who observed significantly faster onset of block with spinal anaesthesia compared to epidural techniques in lower abdominal surgeries (6). Jindal et al. also reported rapid and dense block with spinal anaesthesia, making it more suitable for short-duration procedures such as hernioplasty (4). Haemodynamic stability is an important determinant of anaesthetic safety, especially in elderly patients who commonly present for hernia surgery. In the present study, a significant fall in blood pressure and heart rate was observed in both groups; however, the magnitude of change was significantly higher in the spinal anaesthesia group. Hypotension occurred in 24% of patients in Group S compared to 10% in Group E (p < 0.05). This can be explained by sudden sympathetic blockade in spinal anaesthesia leading to vasodilatation and reduced venous return. Epidural anaesthesia, on the other hand, produces a segmental and gradual sympathetic block, resulting in better cardiovascular stability. A similar observation was made by Singh et al., who reported greater haemodynamic fluctuations with spinal anaesthesia compared to epidural anaesthesia in lower abdominal surgeries (9). Bajwa and Kulshrestha also emphasized that epidural anaesthesia offers better haemodynamic control due to gradual onset of sympathetic blockade, particularly beneficial in high-risk patients (7). One of the most significant findings of the present study was the markedly longer duration of postoperative analgesia in the epidural group (320 ± 45 minutes) compared to the spinal group (180 ± 35 minutes) (p < 0.001). This can be attributed to the ability of epidural anaesthesia to provide continuous analgesia through catheter-based drug administration and prolonged segmental blockade. In contrast, spinal anaesthesia provides a fixed duration of action determined by the pharmacokinetics of the drug used. Ranjan et al. reported similar findings, demonstrating that epidural anaesthesia significantly prolongs postoperative analgesia and reduces the requirement of systemic analgesics (11). Ahuja and Mitra also highlighted that epidural techniques are particularly useful for postoperative pain management in lower abdominal surgeries due to their flexibility and prolonged action (8). Effective postoperative analgesia is crucial in inguinal hernioplasty as inadequate pain control may delay ambulation, increase pulmonary complications, and prolong hospital stay. Epidural anaesthesia therefore offers a distinct advantage in enhancing recovery. In the present study, the overall incidence of postoperative complications was higher in the spinal anaesthesia group (36%) compared to the epidural group (20%), although the difference was not statistically significant. Hypotension-related symptoms, nausea, vomiting, and urinary retention were more frequent in the spinal group. These findings are consistent with the sympathetic blockade associated with subarachnoid anaesthesia. Post-dural puncture headache was observed only in the spinal group, which is a known complication due to dural puncture and CSF leakage. Gupta et al. reported similar complication profiles in spinal anaesthesia, including hypotension and PDPH as the most common adverse effects (6). Bajwa et al. emphasized that although both techniques are safe, spinal anaesthesia is more frequently associated with haemodynamic disturbances compared to epidural anaesthesia (7). The findings of the present study suggest that both spinal and epidural anaesthesia are safe and effective for inguinal hernioplasty; however, each technique has distinct advantages. Spinal anaesthesia offers rapid onset, dense block, and technical simplicity, making it ideal for short procedures and day-care surgeries. Epidural anaesthesia, on the other hand, provides superior haemodynamic stability and prolonged postoperative analgesia, making it more suitable for patients where extended pain relief is desired. In the Indian clinical context, where resource optimization and cost-effectiveness are critical, spinal anaesthesia remains the most commonly used technique. However, with increasing emphasis on enhanced recovery after surgery (ERAS) protocols, epidural anaesthesia may play a more significant role in selected patients.

It may be concluded that spinal anaesthesia is preferable for short-duration procedures requiring rapid onset and technical simplicity, whereas epidural anaesthesia is more advantageous when prolonged postoperative analgesia and better haemodynamic stability are desired. The choice of anaesthetic technique should therefore be individualized based on patient condition, surgical requirements, and available expertise.

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