*4.2.3 Subcostal block of the quadratus lumbar*

Insertion of the needle is caudal to the transducer in a lateral or medial cranial direction, the deposit of the local anesthetic is between the quadratus lumbar and the psoas muscles (**Figure 11**) [23, 26].

#### **Figure 9.**

*Anterior quadratus lumborum block: transverse oblique paramedian approach. Transverse transducer and posteroanterior needle trajectory are shown. The external image and ultrasound images show the ultrasound probe position with an arrow indicating the needle trajectory. The blue-shaded area represents the spread of the local anesthetic.*

**Figure 10.** *Quadratus lumborum block: A technical review.*

#### **Figure 11.**

*Anterior quadratus lumborum block: subcostal approach. Parasagittal oblique transducer and caudal-tocranial needle trajectory are shown. The external image and ultrasound images show the ultrasound probe position with an arrow indicating the needle trajectory. The blue-shaded area represents the spread of the local anesthetic. EO, external oblique; ES, erector spinae; IO, internal oblique; PM, psoas major; QL, quadratus lumborum; TA, transversus abdominus; TP, transverse process.*

#### **4.3 Indications**

It is indicated for lower abdominal surgeries, including Cesarean section, colostomy closure, hernia repair, gastrectomy, nephrectomy, hip replacement, above-knee amputation, iliac crest bone graft, and iliac and acetabulum fracture [23, 26, 27].

It has been shown that posterior quadratus lumborum block with 0.125% bupivacaine reduces opioid needs for 12 h postoperatively compared with placebo in patients who were administered the combination of bupivacaine 15 mg plus fentanyl 20 mμ. Similarly, Mieszkowski et al. [28] showed that the group that received the quadratus lumborum block (bupivacaine 0.375%, 24 mL) decreased the consumption of opioids (morphine 4 mg) vs. the placebo group that received the standard anesthetic technique (bupivacaine 0.5% 12.5 mg plus 20 mcg fentanyl).

While intrathecal morphine is the current standard drug, quadratus lumborum block offers superior pain control with fewer side effects. The study by Pangthipampai et al. [29] compared the pain-free period after Cesarean delivery among women in labor who received spinal block with 0.2 mg IT morphine, 0.2 mg IT morphine and bilateral QLB (bupivacaine 0.25% 25 ml), or alone. Using bilateral QLB (bupivacaine 0.25% 25 mL), it was concluded that quadratus lumborum block together with IT morphine had a longer pain-free period compared with standard IT morphine alone, but that quadratus lumborum block without association did not provide inferior pain compared with standard IT morphine. However, research by Irwin et al. [30] describes that there was no difference in pain scores up to 48 h after this block (40 ml of 0.25% levobupivacaine) or sham block after undergoing elective Cesarean section under spinal anesthesia and IT morphine.

#### **4.4 Complications**


#### **5. Erector spinae plane block**

The erector spinae plane block (ESP) is an interfascial analgesic block first described by Forero in 2016 for the treatment of neuropathic thoracic pain. A vast body of scientific literature related to this procedure has been developed, thus increasing the indications for this analgesic blockade given the analgesic efficacy and relative ease at the time of reproducing said procedure in different patients, even more so now that a multimodal approach to pain management is performed [31, 32].

The anatomical basis for performing this block is in the paravertebral musculature, in the thoracolumbar fascia on the transverse processes and the muscular group called the erector spinae made up of the spinalis, longissimus thoracis, and iliocostalis muscles, in addition to the transverse-spinal muscles and levatores rostrum. The deposit of local anesthetic at this level generates its diffusion toward

#### *Ultrasound-Guided Regional Analgesia for Post-Cesarean Pain DOI: http://dx.doi.org/10.5772/intechopen.101465*

the vertebral and epidural space as well as the intercostal space, thus managing to cover the dorsal and ventral branches of the spinal nerves from their emergence at the level of the site of injection as well as a diffusion toward cranial and caudal between three and four levels demonstrated by Chin et al. [33] in cadaveric studies, reason for achieving both somatic analgesia of the posterior and antero-lateral thoracoabdominal wall, as well as visceral [34, 35].

Regarding the technique, it should be considered that since it is an invasive procedure, the patient must be previously monitored in addition to complying with the standard of asepsis and antisepsis of each institution. Once this prerequisite has been carried out, the block can be performed with the patient awake or under general anesthesia if applicable, always guided by ultrasound to achieve greater effectiveness when blocking the area. However, there is a description of the block by means of anatomical references. The positioning of the patient will depend on the patient's state of consciousness, being possible to perform the procedure in a sitting position, lateral decubitus, or prone.

Performing the ESP block by anatomical reference takes as its starting point palpation of the spinous processes of the level to be blocked, for gynecological/obstetric abdominal procedures such as Cesarean section. It is performed at the T9 level, and then, it is displaced 3 cm laterally to try to palpate the transverse processes, the site where we are going to perform the puncture perpendicular to the skin with a G22 needle or a G18 Tuohy needle until the transverse processes are located at an approximate distance of 2–4 cm deep, although this could vary if we take into account the physiological changes that occur in pregnant women [2, 31, 32, 34, 35]. The injection of the local anesthetic is performed prior to negative aspiration to avoid inadvertent intravascular injections, interspersed with boluses of 5 mL of anesthetic solution. Similarly, to carry out this ultrasound-guided procedure, the transducer is placed in an axial direction at the level of the spinal process and later, the transverse processes are traced and we turn the transducer in a longitudinal direction and thus observe the muscular distribution of the erector spine and its deep fascia visualized in a hyperechoic way on the acoustic shadow generated by the transverse process. The administration of the anesthetic solution is carried out in the same way as for anatomy references, injections of 5 mL after negative aspirations until an average volume of between 15 and 20 mL or 0.2 mL/kg per side is completed to visualize how the deep fascia is distended (**Figure 12**) [2, 31, 32, 34, 35].

The indications for performing this block fall into a very wide range since there is a number of bibliographies in which better analgesic control and a decrease in the requirement of opioid analgesics is reported in the postoperative period in various thoracic and abdominal surgeries. However, to date the administration of intrathecal morphine remains the gold standard for analgesic management for

#### **Figure 12.**

*Sonoanatomy of ESP Block at the T5 level. TP: transverse processes, T: trapezius muscle, RM: rhomboid major muscle, ESP: erector spinae muscle, Pl: pleura. \* Needle point [3, 4].*

#### *Topics in Regional Anesthesia*

elective cesarean sections, as recommended in the PROSPECT study [3], where they place regional blocks as an alternative for cases in which there is a contraindication to approach the neuraxis and consequently, the administration of IT morphine or an IT opioid is not available. Although it is true, most of the references point to a benefit in performing the ESP block for analgesic management. This bibliography is mostly case reports or case series and there are very few studies with a high level of evidence to support the widespread use of regional analgesia in Cesarean sections [2, 36, 37].

Hamed et al. [38] compared IT morphine at a dose of 100 μg with the execution of the ESP block without IT opioid administration, in 140 studied patients no statistically significant difference was found in the perception of pain during the 24 hours after surgery, both at rest and with Valsalva maneuvers (cough), or in reducing the consumption of postoperative opioid analgesics. However, the study reports methodological limitations that could be biasing the result, but the usefulness is emphasized as a multimodal analgesic management in obstetric patients.

In prospective studies in which ESP block was compared with TAP block, such as the one by Malawat et al. [7], as well as by Boules et al. [39], superiority is defined for ESP block for analgesic management and reduction of the requirement postoperative analgesic in series of 60 patients analyzed in each study (ropivacaine 0.2%,2 mL/kg in each puncture). However, there was an important difference in the duration of analgesic effects, reaching around 43 h of analgesia with ESP vs. 12 h with TAP block in the report by Malawat contrasting with that described by Boules, who stated that the ESP block provided 12 h of analgesia compared with 8 h of the TAP block.

Complications or adverse effects with this regional block are rare, especially if it is performed guided by ultrasonography. Despite this, there are reports of unexpected motor blockade of the lower limbs due to the spread to the paravertebral and epidural space, latent risk of pneumothorax due to an inadvertent pulmonary puncture, as well as allergic reactions or cases of poisoning by local anesthetics when administering an excessive dose since a high volume of anesthetic solution is administered or an inadvertent injection into a blood vessel. It is important to perform all these procedures in a place that has the resolution capacity in case of any complication, as well as the personnel trained to carry them out [2, 38, 40].

#### **6. Discussion**

Cesarean delivery is one of the oldest and best established surgical procedures in the history of medicine and is currently the most common major surgery performed on humans anywhere in the world. Postoperative pain management after Cesarean section fairly varies from non-obstetric surgeries; women need to recover rapidly to take care of their newborn baby. Ideal pain treatment is mandatory for the success of immediate-term and long-term rehabilitation after Cesarean delivery. There is growing evidence that perioperative pain management has consequences extending well beyond the immediate recovery period. Unalleviated acute postoperative pain is a striking risk factor for the development of chronic post-Cesarean pain.

Undoubtedly, the gold standard has for decades been the use of intrathecal morphine in doses ranging from 50 to 100 mμ. Multimodal analgesia or balanced analgesia has significantly improved the management of acute post-Cesarean pain, being the combination of drugs mandatory to achieve satisfactory and effective pain relief with reduced side effects. Paracetamol, NSAIDs, magnesium sulfate, alpha2 agonists, dexamethasone, and ketamine are some of the non-opioid drugs used in multimodal analgesia.

There are numerous post-Cesarean regional analgesia techniques that have been studied for decades; from epidural analgesia with or without opioids, intrathecal morphine, intraperitoneal instillation, or surgical wound infiltration with local anesthetics have demonstrated analgesic effectiveness. The advent of ultrasoundguided regional blocks has come to revolutionize post-Cesarean analgesia, showing to be a very safe, effective technique with fewer side effects than other analgesia modalities.

The TAP block has been shown to be the most effective block reducing pain, reducing the use of rescue analgesics and increasing the satisfaction of postpartum women [8, 9, 15]. The posterior approach produces better analgesia than the lateral approach. The addition of dexamethasone, clonidine, or dexmedetomidine prolongs the analgesic effect of this block and reduces the doses of rescue analgesics [17, 18]. The addition of alpha2 agonists induced mild sedation. When ilioinguinal and iliohypogastric nerve blocks are combined with TAP blocks, better analgesia is obtained and the need for salvage opioids is reduced [19, 20].

Another alternative is the quadratus lumborum block [27–29]. Although there are very varied results, there are studies that found better analgesia than with TAP block, but it is not superior to epidural analgesia or intrathecal morphine. More research is required comparing this type of analgesic block with the most commonly used blocks.

Erector spinae plane block is another possibility of ultrasound-guided analgesia as it produces satisfactory pain reduction when compared with intraspinal morphine and TAP block [38, 39].
