European Journal of Cardiovascular Medicine

Peripheral nerve blockade (PNB) has gained significant recognition as an effective and versatile analgesic technique across various surgical specialties, owing to its ability to provide targeted pain relief while minimizing systemic side effects [1]. Extensive research has underscored the critical importance of optimal postoperative pain management in facilitating early mobilization, improving functional recovery, and reducing overall morbidity following surgical interventions [1-4]. The provision of effective surgical anesthesia for procedures involving the entire lower extremity can be achieved using multiple anesthetic techniques, including regional anesthesia and central neuraxial blocks such as spinal or epidural anesthesia [1-5].

Regional anesthesia is increasingly favored for lower limb surgeries due to its ability to provide effective analgesia while minimizing systemic complications. Peripheral nerve blocks (PNBs) have emerged as a widely utilized analgesic technique across various surgical disciplines, offering precise pain control with minimal physiological disruption. In critically ill patients with significant comorbidities or polytrauma requiring emergency surgical intervention, PNBs serve as the preferred anesthetic approach, as they help maintain hemodynamic stability and reduce the risks associated with systemic anesthetic techniques [5].

Among the regional anesthetic techniques, a combination of femoral and sciatic nerve blocks has emerged as a reliable alternative to provide effective anesthesia for lower limb surgeries [2-4]. The femoral nerve block primarily targets the anterior thigh, knee, and medial aspects of the calf, ankle, and foot, ensuring adequate sensory blockade in these regions [3]. On the other hand, the sciatic nerve blockade, which can be administered through various anatomical approaches, has been widely employed to manage postoperative pain, particularly following foot and ankle surgeries [1,2,6,7].

PNBs are particularly advantageous in lower limb surgical procedures due to the anatomical distribution of sensory and motor nerves in the extremity and their ability to selectively interrupt pain pathways at multiple levels while preserving autonomic stability [2]. Compared to conventional anesthetic techniques such as general or spinal anesthesia, a well-executed peripheral nerve block reduces the risk of hemodynamic fluctuations, minimizes the need for systemic opioid administration, and enhances patient comfort during the perioperative period [6]. Additionally, the use of PNBs has been associated with lower incidences of nausea, vomiting, and other systemic complications, contributing to a more favorable recovery profile and expedited hospital discharge [6].

Given these advantages, the present study was conducted to evaluate the clinical efficacy and safety of combined femoral (3-in-1) & sciatic nerve block in a range of lower limb surgical procedures. Specifically, the study aimed to assess the effectiveness of this technique in providing surgical anesthesia and postoperative analgesia while maintaining hemodynamic stability in patients undergoing such interventions.

This study was conducted on a total of 30 patients who were admitted for either elective or emergency lower limb surgery.

Pre-Anesthetic Preparation: All patients underwent a thorough preoperative evaluation, including a detailed examination of all organ systems and routine laboratory investigations. The planned anesthetic procedure was explained to each patient, and efforts were made to alleviate any anxiety. Written informed consent was obtained from all participants. Patients were instructed to observe an overnight fasting period before surgery, and those with systemic illnesses continued their prescribed medications as scheduled.

Materials and Equipment: The anesthetic agents used in the study included Lignocaine 2% with adrenaline (1:200,000), Bupivacaine 0.5%, and Sodium bicarbonate. Distilled water was used for dilution where necessary. Disposable syringes (10 mL), insulated stimulating needles (5 cm and 10 cm in length), and a peripheral nerve stimulator with electrodes were utilized. Additional sterile equipment, including gloves, drapes, a skin marker, cotton swabs, gauze pieces, swab holders, a sterile bowl, Betadine, and spirit, were also prepared. To ensure patient safety, all necessary drugs and equipment for general anesthesia and emergency resuscitation were readily available to manage potential block failures or toxic reactions.

Preoperative Procedure: Before administering the nerve block, intravenous (IV) access was established, and oxygen was delivered via a face mask. Continuous electrocardiographic (ECG) monitoring, non-invasive blood pressure (NIBP) measurement, and pulse oximetry were maintained throughout the procedure. As part of the premedication, all patients received an intravenous injection of Glycopyrrolate (0.2 mg) prior to the initiation of the nerve block.

Anesthetic Techniques:

1. Sciatic Nerve Block (Posterior Approach – Labat’s Technique)

The sciatic nerve block was performed using the posterior classical approach described by Labat. The patient was positioned laterally, with the side to be blocked placed uppermost. The lower leg remained straight, while the upper leg was flexed at the hip and knee, positioning the ankle over the contralateral knee. Key anatomical landmarks for the procedure included the greater trochanter, the posterior superior iliac spine (PSIS), and the sacral hiatus.

A line was drawn between the greater trochanter and the PSIS, and from its midpoint, a perpendicular line was extended downward over the buttock. The injection site was identified 3–5 cm along this perpendicular line. For precise localization, a third line was drawn between the greater trochanter and the sacral hiatus, with the intersection of this line and the perpendicular line marking the injection site.

A 10 cm insulated needle connected to a nerve stimulator was inserted at a right angle to the skin. As the needle advanced, initial twitches of the gluteal muscles were observed, indicating a superficial position. Deeper advancement of the needle elicited brisk responses from the sciatic nerve, seen as twitches in the hamstrings, calf, foot, or toes. Once the optimal response was obtained, the stimulating current was reduced to 0.5–0.9 mA. After confirming the absence of vascular aspiration, 15–20 mL of local anesthetic was injected slowly. Any resistance during injection prompted slight withdrawal and repositioning of the needle to avoid intraneural injection.

2. Femoral (3-in-1) Block (Winnie’s Inguinal Perivascular Approach)

For the femoral nerve block, patients were placed in the supine position with the leg extended. The puncture site was located 1–2 cm below the inguinal ligament and 0.5–1 cm lateral to the femoral artery pulsation. After sterilizing the skin, a small volume of local anesthetic was injected subcutaneously to anesthetize the insertion site.

With the anesthesiologist palpating the femoral artery, the needle was inserted immediately lateral to the artery and advanced in a sagittal and slightly cephalad direction. The nerve stimulator was set to deliver 0.5–0.9 mA, with the first response typically being a visible contraction of the quadriceps muscle (patellar twitch). After confirming proper needle placement and performing a negative aspiration test, 30 mL of local anesthetic was injected to achieve blockade of the femoral, obturator, and lateral cutaneous nerves of the thigh. Firm pressure was applied 2–4 cm below the injection site to facilitate proximal spread of the anesthetic toward the lumbar nerve roots. For surgeries below the knee that did not require a tourniquet, a lower volume (5–10 mL) was used to selectively block the saphenous (femoral) nerve.

Assessment of Block: The efficacy of the nerve blocks was assessed using both sensory and motor evaluations.

Sensory Block: Evaluated using a pin-prick test with a 3-point scale: 0 = Normal sensation; 1 = Blunted sensation; 2 = No perception

Onset time was recorded as the interval between injection and a score of 1 on the scale. Duration was measured from onset to the patient’s first analgesic request.

Motor Block: Assessed using the "Three P’s" acronym:

Push: Inability to plantar flex the foot against resistance indicated sciatic nerve blockade.

Pull: Weakness in adduction of the leg toward the midline suggested obturator nerve involvement.

Punt: Inability to extend the knee against resistance confirmed femoral nerve blockade.

The Bromage scale was used for grading motor block: 0 = Normal function; 1 = Decreased strength compared to the contralateral limb; 2 = Complete motor block

Onset time was recorded as the time from injection to the first sign of motor weakness, and duration was measured until the restoration of normal motor function. A successful block was defined as complete sensory and motor blockade within 30 minutes, allowing for pain-free surgery without the need for supplemental anesthesia. Sedation was administered before the procedure using Midazolam (0.02 mg/kg) and Fentanyl (1 µg/kg) intravenously.

Intraoperative and Postoperative Monitoring: Patients were closely monitored intraoperatively and postoperatively for complications such as vascular puncture, local anesthetic systemic toxicity, cellulitis, nerve injury, or skin infections at the injection site. Postoperatively, patients were observed in the ward until full recovery of sensory and motor function.

Preoperative Considerations: During the preoperative assessment, any comorbidities such as hypertension, diabetes mellitus, anemia, or respiratory infections were identified and optimized before surgery. A careful examination of the skin at the injection site was performed to rule out infections or contraindications to regional anesthesia.

In this study, a total of 30 patients were included, with baseline characteristics summarized in Table 1. The majority of participants were male (80%), while 20% were female. Regarding age distribution, the largest group was in the 51-60 years age range, comprising 40% of the participants, followed by the 41-50 years age group at 16.66%. The other age groups (11-20, 21-30, 31-40, 61-70, and 71-80 years) made up smaller proportions of the study population. In terms of weight, the highest percentage of patients (46.67%) fell into the 51-60 kg range, followed by 33.33% in the 61-70 kg range. The majority of patients underwent elective surgeries (63.33%), with 36.66% undergoing emergency procedures. Nerve blocks were administered to all patients, with 96.66% receiving femoral, obturator, and lateral cutaneous nerve blocks, while 90% received the sciatic nerve block.

Table 1: Baseline profile of study cases

The details of nerve block parameters are provided in Table 2. The sensory block onset time ranged from 5 to 14 minutes, with a mean time of 9.03 ± 2.10 minutes, and the sensory block duration ranged from 160 to 230 minutes, with a mean of 195.66 ± 19.10 minutes. The motor block onset time varied between 8 and 20 minutes, with a mean of 13.86 ± 3.35 minutes. The duration of the motor block ranged from 130 to 185 minutes, with a mean of 158.5 ± 14.63 minutes. As for the quality of the block, the majority of patients (90%) achieved a complete block, while 6.66% had an incomplete block and 3.33% had a failed block.

Table 2: Details of Nerve block parameters

Table 3 presents the hemodynamic parameters recorded preoperatively and postoperatively. For heart rate, the range before surgery was 60-110 bpm, with a mean of 83.96 ± 11.90 bpm, and postoperatively, it ranged from 62-98 bpm, with a mean of 82.9 ± 9.04 bpm. Systolic blood pressure (SBP) preoperatively ranged from 90 to 170 mmHg, with a mean of 125.13 ± 17.32 mmHg, and postoperatively, the range was 102-160 mmHg, with a mean of 123.8 ± 13.02 mmHg. Diastolic blood pressure (DBP) preoperatively ranged from 60 to 100 mmHg (mean: 78.06 ± 10.06 mmHg), and postoperatively, it ranged from 60 to 96 mmHg (mean: 77.6 ± 8.32 mmHg). There were minimal changes in the hemodynamic parameters between the preoperative and postoperative measurements.

Table 3: Hemodynamic parameters

As shown in Table 4, there were no recorded complications related to the nerve blocks. Specifically, there were no cardiovascular, neurological, or vascular puncture complications, and no pain was reported at the injection site in any of the patients.

Table 4: Complications of Nerve Blocks

This study aimed to evaluate the clinical effectiveness of a combined femoral (3-in-1) and sciatic nerve block as the primary anesthetic approach for lower limb surgeries. Peripheral nerve block (PNB) has proven to be a highly effective and practical alternative for unilateral lower extremity surgical procedures.

In this study, the sciatic nerve block was administered using the posterior Labat approach [1] with 15 mL of local anesthetic (5 mL of 0.5% bupivacaine and 10 mL of 1.5% lignocaine with adrenaline at a ratio of 1:200,000). The femoral (3-in-1) block was performed through Winnie’s inguinal perivascular approach [2], utilizing 30 mL of local anesthetic (10 mL of 0.5% bupivacaine and 20 mL of 1.5% lignocaine with adrenaline at a ratio of 1:200,000). For patients with compromised renal function, lower concentrations of anesthetic agents were employed to mitigate potential adverse effects. Additionally, in cases involving surgery below the knee without a tourniquet, only the femoral nerve block was performed instead of the 3-in-1 block.

Age Distribution: A majority of the patients in this study belonged to the 51–80-year age group, with a mean age of 48.6 ± 15.5 years. This selection was made to evaluate the efficacy of PNBs in minimizing the risks and disadvantages associated with general anesthesia (GA) or central neuraxial blockade (CNB) in individuals with cardiac, pulmonary, or renal comorbidities. A study by Raj Kumar et al. [6] reported the application of combined sciatic and femoral (3-in-1) blocks in high-risk elderly patients undergoing lower limb amputations, with an average age of 70.71 ± 8.73 years.

Onset of Sensory Block: The time required for the sensory block to reach a grade 1 level in areas supplied by the femoral, obturator, lateral cutaneous, and sciatic nerves was measured. In this study, the mean onset time for sensory blockade was 9.03 ± 2.10 minutes (Table 10), which was comparable to findings by A. Singh et al. [7], who reported an onset time of 12.6 ± 5.36 minutes. Other investigations, such as that by V. Chakravarthy et al. [8], noted an onset time of 20.3 ± 4.7 minutes, but they employed a higher volume (50 mL) of 1% lignocaine.

Onset of Motor Block: The onset of motor block was defined as the time from the administration of the local anesthetic to a grade 1 Bromage scale response. In this study, the motor block onset time was 13.86 ± 3.35 minutes (Table 11), whereas A. Singh et al. [7] reported a motor block onset of 21.3 ± 9.94 minutes using 1% lignocaine and 0.25% bupivacaine. Sensory blockade was consistently observed before the onset of motor blockade, which can be attributed to the fact that motor nerve fibers are thicker and located more centrally within the nerve bundle.

Duration of Sensory Block: The duration of sensory blockade was influenced by factors such as the type, dose, and concentration of local anesthetic, which were standardized across all study participants. Defined as the time from sensory block onset to the first analgesic request, the mean duration of sensory blockade was 195.66 ± 19.10 minutes. These results were in agreement with studies by V. Chakravarthy et al. [8], who reported a sensory block duration of 203.1 ± 29.8 minutes, and Fournier et al. [9], who observed a sensory blockade lasting 4–6 hours following a 3-in-1 block.

Duration of Motor Block: The average duration of motor blockade in this study was 158.5 ± 14.63 minutes. V. Chakravarthy et al. [8] reported a motor block regression time of 180 ± 22.5 minutes when using 50 mL of 1% lignocaine for the combined sciatic and 3-in-1 block. In contrast, our study utilized 30 mL of 1.5% lignocaine with adrenaline (1:200,000) and 20 mL of 0.5% bupivacaine.

Hemodynamic Stability: Heart rate, as well as systolic and diastolic blood pressure, were monitored preoperatively, intraoperatively, and postoperatively. No significant fluctuations in these parameters were observed (p > 0.05). These findings align with studies by Raj Kumar et al. [6], A. Singh et al. [7], V. Chakravarthy et al. [8], Fowler et al. [10], Gligorijevic et al. [11], Zaric et al. [12], Barton et al. [13], Casati et al. [14], Fanelli et al. [15], and Singelyn et al. [16], all of whom reported no significant hemodynamic alterations throughout the perioperative period.

Block Success Rate: Achieving successful PNB requires accurate nerve localization, precise needle positioning, and proper local anesthetic administration. In this study, the femoral (3-in-1) and sciatic nerve blocks were executed using a nerve stimulator technique. Among 30 patients, 27 achieved a complete block, while 3 experienced an incomplete block, resulting in a 90% success rate. For the three patients with incomplete blockade, general anesthesia with endotracheal intubation and controlled ventilation was administered, maintained with oxygen, nitrous oxide, sevoflurane, and a muscle relaxant. A. Singh et al. [7] also reported a high success rate with a low failure incidence (4%), while Raj Kumar et al. [6] documented a 94.44% success rate, findings consistent with those of the present study.

Complications: No complications were observed in any patient during or after surgery. These results are in line with studies by Zaric et al. [12], who reported a lower incidence of complications (p < 0.05) in the PNB group compared with the epidural group. Singelyn et al. [16] demonstrated that continuous 3-in-1 blocks led to four times fewer complications than epidural analgesia. Fowler et al. [10] found that PNBs provided effective unilateral analgesia with fewer opioid-related and autonomic side effects, as well as a lower incidence of serious neurological complications compared to epidural anesthesia. Similarly, Raj Kumar et al. [6] observed no intraoperative or postoperative complications.

In conclusion, the combined femoral (3-in-1) and sciatic nerve block is a straightforward, safe, and highly effective anesthetic technique with minimal side effects and an exceptionally low failure rate. This approach provides superior anesthesia and analgesia for a range of unilateral lower limb surgeries, particularly benefiting high-risk patients by eliminating the need for invasive monitoring. Given its advantages, including cost-effectiveness and a favorable safety profile, it is highly probable that well-executed peripheral nerve blocks will increasingly replace general anesthesia and central neuraxial blockade for lower limb surgeries in the near future.

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