Research progress on the clinical application of lumbar muscle block

Author: Chen Meiping, Chen Zhicong, Department of Anesthesiology, Shenzhen Second People's Hospital

Quadratus lumborum block (QLB) was first proposed by Blanco in 2007 and described as a transverse abdominal muscle plane block

In recent years, there have been many controversies among scholars about different puncture approaches and their analgesic mechanisms, which vary greatly in clinical application due to different operating methods

1.

Muscles: The lumbar muscles start from the medial margin of the iliac crest and end upward at the L1-L4 transverse process and the inferior 12th costal margin

Fascia: thoracolumbar fascia (TLF) is a continuous connective tissue from the occipital bone to the sacrum and consists

Nerves: QLB can achieve skin hypoesthesia at the T12-L2 level through various puncture approaches, indicating that the subilioventral nerves, iliac inguinal nerves, and subcostal nerves can be blocked

The dorsal branch of the spinal nerve passes through the middle layer of the thoracolumbar fascia behind the lumbar muscle to enter the erector spinal muscle, which acts as a function of innervating the erect spinal muscle

Vascular: the ventral support of the iliolumbar artery starts from the abdominal aorta, travels laterally and posteriorly of the lumbar muscle, adjacent to the lumbar muscle, or within the substance of the lumbar muscle, and may be injured during puncture, so color ultrasound Doppler confirmation

2.

Lateral approach lumbar muscle block: the puncture target is located at the anterolateral intersection of the

The needle is injected from within the plane of the probe's anterior margin, through the three layers of the abdominal wall muscles to the anterolateral margin of the posteromedial lumbar muscle, where local anesthesia is

Posterior lumbar block: the puncture target is located behind the lumbar muscle, between

Anterior lumbar block: Also known as intermuscular QLB, local anesthesia is injected in front of the lumbar muscle, between

Elsharkawy et al.

Local anesthesia is injected between the psoas muscle and the front layer of TLF, and the liquid spreads to the side of the head in a moon-shaped distribution, and the front layer of TLF can be seen to move

Intramuscular lumbar block: the puncture target is located within

3.
Clinical application of lumbar muscle block

QLB has a wide range of applications, and there have been cases of caesarean section surgery, gastrointestinal surgery, urological surgery, lower extremity surgery, chronic pain treatment, etc.
in clinical practice
.
Jin et al.
, by including a meta-analysis of 22 clinically randomized trials of QLB, showed that QLB is certain to reduce opioid use after caesarean section and kidney surgery, while evidence for its role in other types of surgery is insufficient
.

Caesarean section: Blanco and other studies have shown that QLB can reduce the amount of morphine used after caesarean section at 6, 12, 24, and 48 hours, and reduce VAS pain scores
at rest for 24 hours after surgery and at all time points.
El-Boghdadly et al.
showed by meta-analysis that patients applying QLB and TAP had a comparable and better analgesic effect at 48 hours postoperative than those without blockade in the absence of intrathecal morphine, but these studies did not support the combination of QLB when using intrathecal morphine because its analgesic effect was not enhanced
.

Gastrointestinal surgery: In order to find the best analgesic method for pediatric abdominal surgery, Ipek et al.
randomly divided 94 children into three groups for comparison, and the results showed that the TAP group had the most postoperative analgesic consumption, the pain score of 2 and 4 hours after surgery in the QLB group was significantly reduced, the hospital stay in the sacral anesthesia group was significantly longer, and the operation time was higher than that of the previous two groups
.
Therefore, QLB can be used as an option
for analgesic methods in children with abdominal surgery.
In the study of laparoscopic rectal cancer resection, Yang Lei and other studies showed that TQL combined with pudendal nerve block was compared with TQL alone, and the former had fewer opioid uses, a lower incidence of adverse reactions, and higher
patient satisfaction.
The reason for this is that surgery requires perianal manipulation, which is innervated by the pudendal nerve originating in the anterior branch of S2-4, and TQL does not provide effective analgesia for perianal analgesia
.

Urological surgery: Elsharkawy et al.
performed unilateral subcostal approach TQL on 22 patients undergoing open urological surgery, and performed pain scoring and dermal hypoesthesia segment assessment for 3 consecutive days, and the results showed that the block segment was T6-7 to L1-2, which could provide appropriate analgesia
.
Aditianingsih and other studies have shown that compared with postoperative analgesia in patients with laparoscopic kidney surgery, continuous TQL and epidural analgesia showed no difference in the cumulative consumption of morphine, postoperative pain score, and sensory block segment in the two groups after 24 hours, and there was less incidence of hypotension and postoperative nausea and vomiting in the QLB group, and the time of indwelling catheter was shorter
.

Lower extremity surgery: Kukreja and other studies have shown that in patients undergoing total hip replacement, TQL can provide satisfactory postoperative analgesia, reduce postoperative 24h VAS pain scores, reduce cumulative opioid dosage, and improve patient satisfaction
.
Yang Chengjie et al.
showed through meta-analysis that the 6-48 hours pain score, 24 hours morphine dosage and nausea and vomiting incidence rate after total hip surgery were ordered from low to high: QLB, iliac fascial block, venous analgesia
.

Leng Xin and other studies have shown that TQL combined with iliac fascial block not only achieved good analgesia in patients with total hip surgery, but also did not have complications
such as lower extremity weakness 。 Johnston et al.
reported a case report on QLB catheterization for total hip replacement, using TQL puncture injection load of 0.
5% ropivacaine 30ml, placed in a catheter 5cm, connected to a continuous analgesic pump, injected at a rate of 10ml/h 0.
2% ropivacaine, a single infusion dose of 4ml, lock time 30min, lasting until 48h postoperatively, can produce a T12-L2 block range, significantly reduce postoperative pain
。 Brixel et al.
in a recent study on total hip replacement showed that multimodal analgesia combined with posterior lumbar block did not reduce opioid use for 24 hours postoperatively, possibly because posterior lumbar block does not block the lumbar plexus nerve
.

Chronic pain: Carvalho et al.
reported a case of chronic pain after multiple hernia repair surgery with posterior lumbar muscle block, and after 60 minutes of bilateral block, the patient's pain score dropped from 8 to 0 points, and no complications
occurred.
To understand the therapeutic effects of QLB in chronic pain, more research
is needed.

4.
Analgesic mechanism of lumbar muscle block

Somatic nerve and thoracic sympathetic nerve trunk block: Since TLF continues with the intrathoracic fascia, local anesthesia drugs can spread along the intrathoracic fascia to the parathoracic space during lumbar muscle block, which can block multiple segments of somatic nerves and thoracic sympathetic nerve trunks, which is generally considered to be the main analgesic mechanism
of QLB.
Dam et al.
cadaver studies have shown that when the L4 line TQL, the dye can spread to the cephalic side to the parathoracic space, and the thoracic sympathetic stem and the ventral branch of the T9-T10 spinal nerve are stained
.
Elsharkawy et al.
also observed in the cadaver study of posterior lumbar muscle block in line L3-4 that the dye spread to the T10 paravertebral space and blocked the T10-L1 nerve roots; When performing subcostal TQL at the L1-2 level, the dye can spread to the T9-T12 paravertebral space, block T9-L1 nerve roots, and even reach the T7 level
.

Tamura et al.
have shown that local anesthesia drugs do not spread
to the parathoracic space when intramuscular QLB is performed at the L3 level.
Thus, infusion of local anesthetic between the transverse abdominal fascia and the lumbar muscles may spread to the paravertebral space, QLB in different planes, and diffuse to both sides of the head and tail to different
extents.

Lumbar plexus root and its branching block: When the lumbar plexus nerve enters the lumbar muscle, the lumbar muscle may be divided into the posterior 1/3 and anterior 2/3 by the fascial layer, so the ventral side of the lumbar muscle remains continuous with the transverse abdominal fascia, which may be a potential route for
the spread of local anesthetic from QLB to the lumbar plexus.
Adhikary et al.
have shown through cadaver studies that TQL at the L3 level can be observed that lumbar plexus nerve roots and subcostal nerves are stained, and L1-L3 is continuously stained
.
But in cadaver studies such as Dam did not observe the spread
of the dye to the lumbar plexus nerve roots.
It is important to note that the range of diffusion of local anesthetic drugs in specimens and humans is different, and it is not possible to rely solely on cadaveric studies to determine their range of
blockage.

Peripheral sympathetic block: another mechanism of action of lumbar muscle block can be explained
by the anatomical features of TLF.
In the posterior layer of TLF, there is a coarse network of sympathetic neurons containing type A and type C fibrous pain receptors and mechanoreceptors, which play a role in the development of both acute and chronic pain, which may be associated
with the posterior lumbar muscle block analgesic mechanism.

Contraindications and complications of QLB are deep blocks, and absolute contraindications include local anesthetic drug allergy, local infection, sepsis, and coagulation dysfunction
.
Relative contraindications include patients with
known neurologic disorders, anatomical abnormalities, and shock.
There have been no reports
of serious complications associated with QLB.
QLB local anesthesia drugs reach the roots or branches of the lumbar plexus nerve through the paravertebral space or transverse fascia of the abdomen, and weakness of the lower extremities may occur
.

Wikner et al.
reported a case of unilateral hip flexion and knee extension weakness after receiving 0.
25% bupivacaine 20ml of lumbar muscle block in patients undergoing laparoscopic endometriosis, which lasted until 18 hours
postoperatively.
Therefore, special attention should be paid to the risk of falls and prolonged hospital stay when applying QLB in elderly patients
.
In addition, there may be a risk of hypotension after QLB puncture, which may be associated
with the spread of local anesthesia to the paravertebral space.
Moreover, larger doses of local anesthetics are required for bilateral blockade, with special attention to the occurrence
of local anesthetic poisoning.

Blanco et al.
have shown that when blocking with the same volume local anesthetic drugs, the peak of the arterial plasma ropivacaine concentration in QLB versus transverse fascial block is significantly reduced
.
In addition to the above concurrent certificates, it is also necessary to pay attention to the risks
of puncture site infection, organ and vascular and nerve damage.

5.
Summary

QLB, as a trunk nerve block, has become a hot spot in the study of fascial block, and six puncture approaches
have been proposed.
Compared with other abdominal wall blocks, QLB can prolong analgesic time, reduce the amount of analgesic drugs, puncture site is far from the abdominal cavity, QLB-related complications are less reported, and are widely
used in clinical practice.
The diffusion mechanism of different puncture pathways is not clear, and the spread range of local anesthesia determines the clinical effect, so more research is needed in the future to observe the diffusion mechanism and the analgesic effect between different approaches, and the exact mechanism of action also needs to be further studied
.

Source: Chen Meiping,Chen Zhicong.
Research progress in the clinical application of lumbar muscle block[J].
Journal of Clinical Anesthesiology,2022,38(03):308-312.