**3.5 Peripheral nerve and fascial blocks**

Nerve blocks consists of the injection of a local anesthetic around a nerve causing pain relief by interrupting transmission of pain signals from the peripheral nerves to the cortex. Nerve blocks for orthopedic procedures have been shown to facilitate the execution of surgery, improve pain control and sleep after surgery, and decrease hospital stay [67, 68]. Nerve blocks may also reduce the need for other analgesic medications, thus limiting associated adverse effects. The hip area is innervated by branches of the lumbar plexus. The hip joint is supplied with femoral and obturator nerves, nerve to quadratus femoris, superior gluteal, and sciatic nerves. The dermatomal supply of the hip joint is typically from spinal nerve roots lumbar-4 to as low as sacral-2. The bony structures of the hip joint are supplied from spinal nerve roots lumbar-3 to sacral-1. It is difficult to achieve complete pain relief of the hip with peripheral nerve blocks [69], and some techniques, such as psoas compartment block, are suggested to be performed by experts [70]. There are many types and techniques for blocking the lumbar plexus nerves following hip replacement:


discovered that nearly half of patients do not have a skin component of the obturator nerve and that assessing adductor strength is the only effective way to measure obturator nerve function [75]. The effect of the FICB is similar to the femoral nerve block, but may provide a more reliable method of reaching the femoral lateral cutaneous nerve.

Compared to systemic analgesia alone, it is known that peripheral nerve blocks reduce postoperative pain, acute cognitive impairment, pruritus, and hospitalization [1]. Compared to neuraxial blocks, there is evidence that peripheral nerve blocks reduce pruritus [1]. Severe adverse events with peripheral nerve blocks are fortunately rare, and the use of ultrasound to guide locoregional anesthesia is highly recommended to reduce the risk of unwanted effects (intravenous puncture, local anesthetic systemic toxicity, and intraneural puncture). The ultrasound allows one to recognize the nerve structures in detail, to see in most cases the progression of the needle toward the target nerve structure, and to visualize the diffusion of the local anesthetic [75]. The combined use of the ultrasound system and the electrical nerve stimulator (ENS) increases the success rate in the localization of the nerve and minimizes the possibility of intraneural [76]. The techniques of regional anesthesia may also be useful for the postoperative pain control administering anesthetic drug continuously through a catheter left in the perineural space providing continuous perineural anesthesia/analgesia. A perineural catheter may be left either around the femoral nerve or around the lumbar plexus. The lumbar plexus (psoas compartment) is the first choice for the placement of the continuous perineural anesthesia for total hip replacement [77]. Ultrasound-guided psoas compartment block can be performed with different approaches (i.e., "Lumbar Ultrasound Trident" and "Shamrock technique") [78] and has a lower hemodynamic impact compared to neuraxial techniques especially in elderly patients. Hence, a good anesthetic plan is guaranteed with the possibility to be extended and with a result comparable to other techniques [79]. Finally, an alternative procedure to those already mentioned is the use of the pericapsular nerve group block (PENG block) with local anesthetic infiltration. This technique is still poorly used, but its use is increasing, and it could be hypothesized as an effective and safety anesthesia technique for the total hip surgery [80].

#### **3.6 General anesthesia and multimodal strategies**

Sedative or anxiolytic drugs may be used to promote patient comfort and/or facilitate the successful completion of technical procedures such as spinal or locoregional anesthesia. Evidences supporting or the preoperative use of sedative or anxiolytic medication to reduce anxiety and accelerate the achievement of discharge criteria are sparse [81]. Short-acting sedative drugs may be used to facilitate successful completion of technical procedures, but routine administration of sedatives to reduce anxiety preoperatively is not recommended. Among patients undergoing elective primary total hip arthroplasty, general anesthesia has been associated with increased odds of adverse events, prolonged postoperative ventilator use, difficult intubation, stroke, cardiac arrest, other minor adverse events, and blood transfusion [82]. In addition, general anesthesia was associated with mild increases in operative time and postoperative room time [82]. General anesthesia has been previously shown to be associated with pulmonary adverse events following total hip arthroplasty [83].

Compared with neuraxial anesthesia, general anesthesia has been reported to be associated with a higher percentage of intraoperative hypotensive events. This

#### *Anesthesia for Hip Replacement DOI: http://dx.doi.org/10.5772/intechopen.104666*

relationship may exist because high-volume surgical centers may be more likely to use spinal anesthesia and may have decreased operative time and room turnover time compared with other centers. In addition, patient extubation likely adds to the postoperative room time. However, despite the significance of these findings, there may be little clinical importance of these minor increases in operating room times [82]. The overall early postoperative mortality in adult patients undergoing hip arthroplasty is low in the absence of risk factors such as severe cardiac hearth failure, chronic obstructive pulmonary disease (COPD), ascites, acute renal failure, and ASA score of 4 or higher. Some studies suggest that there is no association between the type of anesthesia received (general versus regional) and early postoperative mortality rates in patients undergoing hip arthroplasty, regardless of type (total versus partial) [84]. Similarly, other studies show no significant difference between the perioperative blood loss and the occurrence of deep vein thrombosis. However, spinal anesthesia was more advantageous than general anesthesia in terms of the occurrence of nausea and length of stay [85]. In general, large multicenter study on hip and knee replacement are in favor of neuraxial techniques over general anesthesia, and this change in practice has been at the core of established Enhanced Recovery after Surgery (ERAS) guidelines [84, 86]. Large epidemiological studies support the decision toward the choice of central neuraxial anesthesia over general anesthesia showing regional anesthesia being independently associated with better outcomes [87]. However, the claimed superiority of regional anesthesia has been questioned by emerging research. In particular, one single-center randomized clinical trial (RCT) performed in established ERAS centers has questioned whether the reduced cardiopulmonary and thromboembolic complications associated with neuraxial techniques in comparison with general anesthesia are relevant when hip surgery is performed in an ERAS setting where the preoperative optimization and early mobilization of the patient are two important pillars [88]. Harsten et al. compared a modern general anesthesia with a traditional high dose of neuraxial anesthesia (bupivacaine 0.5% 3 mL) and found no clinically relevant differences in functional recovery, hospitalization, urinary complications, and mobilization [88]. General anesthesia may also reduce urinary bladder dysfunction and rare, but potentially severe, neurological complications [89]. Another strategy that may be adopted consists in a multimodal strategy that involved general anesthesia, often conducted with supraglottic airway device, with regional anesthesia most frequently associated with lumbar block. Compared to general anesthesia with endotracheal intubation and combined spinalepidural anesthesia, general anesthesia with supraglottic airway devices and nerve block had better postoperative analgesic effect and less disturbances on intraoperative hemodynamics and postoperative cognition for elderly patients undergoing intertrochanteric fracture surgeries [90]. Besides the improvement of hemodynamic stability, other advantages of general anesthesia with supraglottic airway device and lumbar plexus and sciatic block (LPSB) included earlier extubation and more rapid weaning from ventilatory support, better control of postoperative pain including longer time to the first analgesic request, and a lower incidence of postoperative complications such as systemic inflammatory response syndrome, pneumonia, sore throat, and hoarseness. In addition, general laryngeal mask anesthesia with LPSB was reported to be associated with a longer postoperative analgesic effect than general anesthesia with endotracheal intubation alone [91]. Another possible option is combining general anesthesia with a supraglottic airway device with fascial block as quadratus lumborum block with or without transversalis fascia plane block) [92, 93]. Preoperative posterior quadratus lumborum block for primary total hip arthroplasty is associated

with decreased opioid requirements up to 48 hours, decreased visual analog scale pain scores up to 12 hours, and shorter postanesthesia care unit length of stay [93]. Conversely, other studies did not report benefits in term of opioid postoperative consumption [79]. Therefore, future multicenter RCTs are warranted to further compare the safety issues and potential differences in postoperative morbidity between different anesthetic techniques.
