Key findings:

Key findings include the advancements in regional approaches for lower limb blocks, driven by the need for effective postoperative analgesia. When central neuraxial blockade is utilized, these blocks are often administered either pre- or post-block. Modern practice emphasizes shorter hospital stays, higher patient expectations, and early mobilization. This article details the current techniques and reasons for performing these blocks, along with postoperative management.

What is known and what is new?

The known aspect is the longstanding practice of utilizing regional approaches for lower limb blocks to provide effective postoperative analgesia. What's new is the evolving emphasis on shorter hospital stays, increased patient expectations, and early mobilization, which are driving advancements in these techniques. This shift underscores the importance of optimizing postoperative care to meet modern healthcare demands and improve patient outcomes.

What is the implication, and what should change now?

The implication is a need for optimized regional blocks for lower limb surgeries to meet modern healthcare demands, including shorter hospital stays and early mobilization. Healthcare systems should prioritize education, resources, and comprehensive care aligned with these standards to improve patient outcomes and meet evolving expectations.

Regional anaesthesia for major lower limb surgery, such as hip and knee arthroplasty, is readily delivered by central neuraxial blockade, eliminating the need for peripheral blocks during the surgical operation. As a result, the rise in popularity of peripheral nerve blocks for lower limb surgery has been attributed to their ability to effectively manage pain and accelerate postoperative mobility. In terms of earlier mobilisation, less postoperative nausea and vomiting, and a shorter hospital stay, pain treatment after lower limb surgery has a substantial impact on the postoperative result as a whole. Both early mobilisation and a shorter hospital stay have been made possible by breakthroughs in anaesthesia, rehabilitation, and surgical techniques [1]. Inadequate pain management hinders early mobilisation and impedes these advancements. Despite substantial adverse effects including nausea and vomiting, hypotension, disorientation, constipation, urine retention, drowsiness, respiratory depression, and pruritus [2], parenteral opioids continue to play a major part in postoperative pain management techniques. These adverse effects are undesirable for patients who want to be mobilised and discharged from the hospital quickly. Capdevila et al.,[3] emphasised the significance of analgesia for maximising postoperative rehabilitation. These authors emphasise the need of incorporating multimodal analgesia into rehabilitation programmes, as well as the need to develop approaches that facilitate early functional recovery.

Regional analgesic treatments (epidural analgesia or 'three-in-one' blocks), according to Singelyn et al.,[4], increase early recovery following unilateral total knee replacement. However, there were no additional significant changes in knee flexion and mobility between the groups six weeks and three months following surgery. Singelyn et al.,[5] failed to demonstrate any advantage of regional analgesia (epidural or femoral nerve block) over morphine patient-controlled analgesia in terms of ambulation, weariness, patient activity, or hospital stay in a traditional rehabilitation programme after hip replacement. However, even if there are no unequivocal, long-term benefits of regional analgesia, nerve blocks are still essential for the administration of high-quality analgesia and an excellent profile of short-term adverse effects. As a result of advancements in anaesthetic procedures and medications, the incidence of mortality and significant morbidity has decreased to the point that it may be difficult to compare these results without massive randomised trials or patient databases. This also includes the local anaesthetic (LA) distribution modalities, such as the use of infusion pumps for patient-controlled regional anaesthesia [6]. Consequently, patient-oriented outcomes such as satisfaction, quality of life, and quality of recovery have gained prominence [7], indicating a growing interest in patient-focused evaluations. All of these new criteria are significant and legitimate outcomes.

The need to obtain a reduced length of hospital stay [8] is one of the primary drives of current practise. For this to occur, adjustments must be made to individual clinical practise, including admissions on the day of surgery and better patient preparation, leading to improved patient expectations and, most crucially, improved postoperative pain management resulting in earlier mobilisation. The postoperative care of nerve blocks is one of the most important determinants of a positive outcome. It necessitates the participation of anesthesiologists, physiotherapists, and, most significantly, the nurses who care for the patient. Before using the approach, the nursing and physiotherapy staff must be thoroughly educated on anatomy, problems, troubleshooting, and pump delivery systems.

 Femoral Nerve Block

The femoral nerve is derived from the lumbar plexus and has a root value of L2–L4. Before becoming more superficial in the anterior thigh, the nerve travels through the substance of the psoas muscle behind the fascia iliaca and then anterior to the iliopsoas muscle under the inguinal ligament. The nerve lies deep to the fascia lata and fascia iliaca. As the femoral artery and vein pass beneath the inguinal ligament, a fascial sheath envelops them. The femoral nerve is located posterior to and laterally of this sheath, not within it. The femoral nerve separates into several branches in the anterior proximal thigh. The anterior thigh, knee, medial side of the calf, ankle, and foot are rendered numb by femoral nerve blockade. The femoral nerve block should be differentiated from the "three-in-one" block and the fascia iliaca block, which aim to anaesthetize the lateral femoral cutaneous and obturator nerves in addition to the femoral nerve.

The femoral nerve can be blocked to offer perioperative analgesia for femoral neck fractures and total hip arthroplasty. When conducted prior to surgery, it aids patient positioning for neuraxial block insertion. Providing preoperative or postoperative analgesia for femoral shaft fractures, surgical anaesthesia for day-case saphenous vein stripping and knee arthroscopy, postoperative analgesia for knee procedures or total knee arthroplasty, and surgical anaesthesia for femoropopliteal bypass surgery are additional indications for femoral nerve block. [9] It is essential to keep in mind that failure to get an opioid-sparing effect in certain knee procedures may be attributable to a lack of blocking of sensory fibres from the sciatic and obturator nerves, which can provide a major amount of the knee's sensory innervation.

The existence of an artificial graft of the femoral artery is a relative contraindication for femoral nerve block. In instances where a thick sensory block might hide the beginning of lower extremity compartment syndrome, such as recent fractures of the tibia and fibula or traumatic and lengthy elective orthopaedic surgeries of the tibia and fibula, the technique is also largely contraindicated. This contraindication does not apply specifically to the femoral nerve block, but rather to regional anaesthesia of the lower extremities in general. Best practise dictates that surgical colleagues should be consulted on the possibility of compartment syndrome development.

Fascia Iliaca Block With Three-In-One Block

 The femoral nerve, the lateral cutaneous nerve of the thigh, and the obturator nerve are the three nerves alluded to in this block. When anaesthesia is sought in the distributions of the obturator, lateral femoral cutaneous and femoral nerves, the 'three-in-one' block is advised. It is simply a modification of the femoral nerve block, and Winnie et al.,[10] were the first to describe it. This technique relies on a single injection of large volumes of local anaesthetic within the neurovascular "sheath" with the needle directed cranially, and the subsequent spread of anaesthetic proximally, assisted by pressure applied distal to the sheath, to achieve anaesthesia in the desired location. Dye injection investigations in cadavers [11] have thrown doubt on whether LA extends proximally to block the obturator nerve, and it has been suggested that when the block is effective, it is due to LA spreading laterally. Even with high quantities (40 ml) of LA, failure to achieve anaesthesia in the distribution of the lateral femoral cutaneous and obturator nerves is typical, according to clinical investigations [12].

Due to the low incidence of obturator nerve block, the "three-in-one" method is best reserved for surgical procedures in the femoral and lateral cutaneous nerve distributions. Therefore, it is unsuitable for individuals having femoral neck surgery, hip reduction, or hip replacement. The fascia iliaca compartment block enables a quicker and more reliable simultaneous blocking of the lateral cutaneous and femoral nerves than the 'three-in-one' block. Both blocks are useful in the early therapy of femoral neck fracture patients who must be relocated and positioned for X-ray evaluation or spinal anaesthesia. A sensory block of the inner thigh region is an early indicator of excellent pain relief [13].

Posterior Lumbar Plexus Block or Psoas Compartment Block

 The lumbar plexus is composed of the anterior divisions of the first three lumbar nerves and the majority of the fourth lumbar nerve; the first lumbar nerve frequently gets a branch from the final thoracic nerve. It is located in the posterior psoas muscle, in front of the transverse processes of the lumbar vertebrae. Practically speaking, while executing a lumbar plexus block, the femoral nerve, lateral cutaneous nerve of the thigh, and obturator nerve are the most important nerves to consider. With a posterior approach, the whole plexus is obstructed as the nerves reach the psoas muscle. It is consequently a reliable technique for the anaesthesia and analgesia of the hip, as well as the anterior portions of the inner and outer thigh up to the knee.

Lumbar plexus block is often used in tandem with central neuraxial blockade or general anaesthesia to provide analgesia for hip replacement or as a stand-alone technique for femoral neck surgery [14]. It has the specific benefit of providing greater postoperative analgesia compared to intravenous opioids or femoral nerve block [15] whether administered alone or in combination. In addition, when a central neuraxial block is contraindicated, it can be utilised in combination with a sciatic nerve block to offer total analgesia of the lower leg. The combination of general anaesthesia with lumbar plexus block is especially advantageous in revision joint replacement surgeries that are anticipated to be lengthy.

Numerous posterior techniques have been developed, with variations on a common theme [16]. Karmakar et al.,[17]  recently characterised the sono-anatomy pertinent to posterior lumbar plexus block and advised its frequent usage, despite the fact that most anesthesiologists now utilise a nerve stimulator-based method. In their publication, they present an ultrasound-guided lumbar plexus block approach that was effectively combined with a sciatic nerve block for anaesthesia in a group of patients having emergency lower limb surgery. In the resulting longitudinal ultrasound picture, the acoustic shadow of the transverse processes generates the so-called "trident sign." Through the acoustic window of the trident, the lumbar plexus appears as many longitudinal hyperechoic striations against a hypoechoic backdrop typical of muscle.

Continuous lumbar plexus approaches provide the benefit of delivering high-quality postoperative analgesia and reducing systemic opioid needs, without the downsides of epidural analgesia, such as urine retention, orthostatic hypotension, and reduced ambulation [18].

Intra-Articular Methods

Infiltration of LA as part of a multimodal analgesic regimen has recently been recommended as a means of enhancing results following total hip and knee replacement [19]. LA infiltration, unlike epidural analgesia and peripheral nerve blocks, is easy, inexpensive, and appears to be safe. Before wound closure, the procedure entails intra-operative injection of the whole surgical region with 100–150 ml of 0.1% levobupivacaine or 0.2% ropivacaine with adrenaline. An indwelling catheter has been retained in place, allowing for recurring injections or infusions, in the majority of investigations using this approach for total knee replacement. Concerns have been raised regarding postoperative infection, and although studies to yet have not demonstrated a rise in infection rate, the research populations has been small, and at least one study has demonstrated considerably higher wound oozing. Certainly, the limited data for total hip replacement demonstrates an improvement in postoperative pain control and a speedier recovery, despite the fact that the infiltration comprised not only bupivacaine, adrenaline, and methylprednisolone, but also morphine [20].

Peters et al., [21] found that patients undergoing total hip and knee replacement who received LA wound infiltration as part of a multimodal peri-operative analgesic regimen had a reduction in pain levels and a quicker rate of recovery. Nevertheless, the study was retrospective, the control group lacked a standardised analgesic procedure, and nonvalidated evaluation methods were utilised. As it is commonly believed that knee replacement is linked with higher postoperative discomfort than hip replacement, it may be argued that the differences observed were attributable to knee patients.

Kerr and Kohan [22] proposed a multimodal method dubbed "local infiltration analgesia" for the treatment of pain following knee and hip surgery. It involves the methodical infusion of ropivacaine, ketorolac, and adrenaline into the tissues around the surgical site in order to produce acceptable pain management with little physiological disruption. The approach permits almost instantaneous mobility and faster hospital release. In this technique, a combination of ropivacaine, ketorolac, and adrenaline is administered around all surgically traumatic tissues, followed by top-up injections via catheter.

Opioid medicines are used sparingly or not at all, in contrast to standard acute pain therapy. Studies comparing outcomes obtained using this approach to those after continuous femoral nerve block or placebo saline injection were the topic of an editorial remark that highlighted future research priorities [23]. Otte et al., [24] recently verified the technique's analgesic effectiveness and simplicity. Incisional infusions of opioids, non-steroidal anti-inflammatory medications, and local anaesthetics are emphasised to be safe and to play a significant role; nevertheless, additional information is needed from several centres regarding their safety and function. In addition, additional detailed studies are required on the volume and concentration of LA used the type and location of catheter for drug administration (i.e. intra-articular or extra-articular administration), the use of single or multihole catheters, and the need for and type of additional systemic analgesic drugs. In subsequent blinded, randomised studies, the optimised infiltration technique should be compared to the current gold standard of continuous peripheral nerve blocks and systemic analgesics, including its potential for enhancing early rehabilitation, achieving discharge criteria earlier, and reducing hospital stay.

Proximal Sciatic Nerve Block

The sciatic nerve is the biggest of the body's peripheral nerves. Its anatomy is well-described in traditional texts. However, like with the vast majority of anatomy, there are numerous variances from the norm that might result in the failure of a regional anaesthetic method. The sciatic nerve has two substantial terminal branches. Although this normally occurs roughly 6.6 cm proximal to the popliteal crease, the division can occur at any level below the greater sciatic foramen, and unrecognised high divisions can lead to partial or unsuccessful blocks [25]. A sciatic nerve block can be used to give perioperative analgesia for hip, ankle, and foot surgery, and is very beneficial for providing postoperative analgesia for lower limb amputation, especially when using a continuous catheter method.

Rapidly growing popularity, ultrasound-guided sciatic nerve block has been recorded in both adults and children [26]. Kamarkar et al., [27] discovered that the subgluteal region is an appropriate location for LA injection or catheter insertion during ultrasound-guided sciatic nerve block. Using ultrasonography, the sciatic nerve may be detected and tracked distally from the subgluteal area using a posterior approach. Between 5.4 and 10.8 cm along its subgluteal path, the sciatic nerve is sufficiently thick and near to the skin in lean volunteers for good ultrasonographic visualisation. [28] The anterior technique can be utilised to detect the sciatic nerve using ultrasound. Ota et al.,[29] demonstrated the practical use of an ultrasound-guided anterior route to sciatic nerve block and compared the block quality and execution time of the anterior method with the posterior subgluteal approach under ultrasound guidance in patients undergoing minor knee surgery. They demonstrated that there were no variations in the beginning of sensory and motor blockage of the sciatic nerve following the block between the anterior and posterior routes and claimed that either technique may be used interchangeably for minor knee surgery. After the anterior approach, sensory block of the posterior femoral cutaneous nerve, which runs parallel to the sciatic nerve in the gluteal area, is seldom accomplished. However, there does not appear to be a disadvantage when a thigh tourniquet is utilised during knee surgery.

Various hypothesised mechanisms causing tourniquet-related pain have been postulated. These include neuropathic pain caused by mechanical compression of fibres, leaving C fibres to conduct pain, direct pain from compression of skin and muscle, and ischaemia-related pain. For lower limb surgery under nerve block, the involvement of the posterior cutaneous nerve of the thigh in tourniquet discomfort remains controversial. When a tourniquet was planned to be used, proximal posterior techniques to block the sciatic nerve, particularly the parasacral approach, were first recommended because they had a greater possibility of blocking the posterior cutaneous nerve of the thigh [30]. Comparing a femoral and proximal sciatic nerve block to a femoral and posterior popliteal sciatic nerve block, and also comparing a posterior approach to the sciatic nerve to an anterior approach that consistently failed to provide sensory block in the distribution of the posterior cutaneous nerve of thigh, have shown comparable rates of tourniquet pain.

Popliteal Sciatic Nerve Block

Several methods have been developed for blocking the sciatic nerve in the popliteal fossa. One or two injections are administered using lateral or posterior techniques [31]. There is some controversy regarding the advantages of two injections to block both the posterior tibial nerve and the common peroneal nerve over a single injection to block only the posterior tibial nerve with both posterior and lateral approaches, with similar success rates reported for each when larger volumes of LA are used [32]. It has been established that ultrasound alone or in conjunction with peripheral nerve stimulation increases success rates at this level. This may be attributed in part to the capacity to display anatomical diversity at this level. Using ultrasound, it is also possible to reduce effective LA volumes. This may make ultrasonography a valuable tool for administering many lower limb blocks to the same patient. A lateral popliteal block may have a poorer success rate than transgluteal techniques, with considerably longer onset durations than both transgluteal and mid-femoral approaches. However, posterior popliteal blocks are linked with significantly less procedure-related discomfort than transgluteal blocks, with no difference in the time required to apply the block, its start time, or its duration.

Simple decreases in postoperative pain scores do not necessarily translate to clinically meaningful improvements in pain relief or outcomes for the patient; therefore, use of a regional anaesthetic or analgesic technique alone does not automatically confer clinical advantage to the patient if overall management is not optimal and not adapted to the needs of the individual patient. Despite this, there is strong evidence that regional anaesthetic of the lower limbs delivers greater postoperative analgesia, which may lead to an improvement in patient outcomes. Adapting a regional anaesthetic procedure to the needs of a particular patient increases its advantages. Regional anaesthesia does not yet have clear evidence that it improves surgical outcomes. However, it is simple to demonstrate the advantages of regional anaesthesia, such as the quality of postoperative analgesia and the reduction of hospital stay and hospital expenditures. The final objective will be to demonstrate that localised analgesia can contribute to long-term functional recovery gains and a reduction in the occurrence of chronic pain.

Funding: No funding sources 

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee of Civil Hospital Palampur

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