The first considerations before performing a nerve block in a patient with pain are safety and efficacy. The Paravertebral Block (PVB) technique has these characteristics and is particularly suitable for the treatment of patients with radicular neuralgia. It has been nearly 80 years since Cleland’s discovery of PVB for pain relief in 1927, and due to the continuous development of pain medicine, the application of PVB for pain management has become more and more widespread. A thorough understanding of the anatomical relationship of PVB before performing it is essential to improve the block effect and prevent complications. In this paper, the concept, role, anatomical basis and technical operation of PVB are introduced as follows: I. Concept and Role The concept of PVB refers to the block method of using a puncture needle through the lateral margin of the vertebral plate to the external port of the intervertebral foramen, and injecting local anesthetics into the external port of the intervertebral foramen via the puncture needle, so as to let the local anesthetics act adequately in the spinal nerve roots being blocked. The role of PVB is mainly used for cervical, thoracic and lumbar surgical anesthesia, post-surgical analgesia, spinal nerve root inflammatory pain and tumor-induced pain treatment. Anatomical characteristics The spinal nerves are merged with the help of the anterior roots (containing motor fibers) and posterior roots (containing sensory fibers) connected with the spinal cord before they exit the intervertebral foramen. The anterior root is the motor root, originating from the anterior horn of the gray matter of the spinal cord, the lateral horn, and the sacral parasympathetic nucleus, which innervates somatic motor neurons and visceral motor neurons. The posterior root is a sensory root that originates from the central eminence of pseudo-unipolar neurons within the dorsal root ganglion of the spinal nerve. The spinal ganglion is an elliptical expansion of the posterior root at the intervertebral foramen and consists of the cytosol of the pseudomonopolar neuron. The peripheral branches of this neuron are distributed in the transverse muscles, smooth muscles, and glands. Before exiting the intervertebral foramen it converges with the anterior root composed of anterior sensory nerve fibers to form a mixed nerve containing both afferent and efferent nerve fibers emanating from the intervertebral foramen. There are seven cervical vertebrae, C1-2 are cricoid and cardinal vertebrae, C7 is similar to thoracic vertebrae, and the rest are ordinary cervical vertebrae. The ordinary cervical vertebrae have smaller vertebral bodies and larger, triangular foramina, with each spinal nerve exiting the intervertebral foramina via the transverse process. The transverse processes of the cervical vertebrae are wide, and the ends of the transverse processes are split into anterior and posterior nodes, with the posterior nodes being larger and shallower, and more easily accessible to the operator than the anterior nodes. There is a foramen transversarium at the root of the transverse process, in which the vertebral artery and vertebral vein pass just anterior to the spinal nerves emanating from the intervertebral foramen. The articular surfaces of the upper and lower articular processes of the cervical spine are approximately horizontal. Compression of different cervical nerve roots can produce persistent pain involving different parts of the body. For example, C2-4 nerve root injury, there can be occipital, posterior cervical, shoulder, anterior cervical region and the upper chest wall range of pain. c5 nerve root injury, there is the medial edge of the scapula and spinal protuberance of the region between the pain. c6 nerve root injury, there is the lateral side of the upper arm and the thumb region of the pain, o biceps tendon reflexes weakened. c7 nerve root injury, there is the dorsal side of the forearm, the palm of the hand weight (俞) Boo straight ellipse small (⑹)bureau of the women’s fortunes Fi8 core酰. o weakened triceps tendon reflexes. The deep layer of the deep fascia of the neck (prevertebral fascia), covering the surface of the cervical segment of the spine extremely anterior and lateral to the prevertebral muscle group and oblique muscle group, up to the base of the skull, and down to the continuation of the intrathoracic fascia that divides the posterior thoracic bib. To the sides encircling the brachial plexus and subclavian artery, this fascia and the cervical vertebrae are interspersed with loose connective tissue called the prevertebral space (in cervical spine tuberculosis, pus can flow into the posterior mediastinum of the thoracic cavity through the prevertebral space). Located between the posterior pharyngeal wall and the deeper layers of the deep cervical fascia (prevertebral fascia), there is also a potential gap of loose connective tissue called the posterior pharyngeal space. Downward, the posterior esophageal space leads to the posterior mediastinum. An irregular cervical paravertebral block may inject medication into the above interspace. The cervical plexus nerve, consisting of the anterior branches C1-4. These four branches interconnect to form three nerve collaterals and give off many branches. The cervical plexus is located in front of the scapularis brevis and middle trapezius muscles and is covered by the sternocleidomastoid muscle. The brachial plexus, consisting of the anterior branch of C5-T1. Five roots of the brachial plexus penetrate from the obliquus interspace and travel behind the subclavian artery into the axilla, forming the medial, lateral, and posterior bundles around the axillary artery. The cervical sympathetic trunk, cervical up to the base of the skull, down to the root of the neck, in the first rib cervical anteriorly continued in the sympathetic trunk deep, sympathetic trunk neck is located in the carotid artery sheath after the transverse processes of the cervical vertebrae, the anterior vertebral muscle and its surface of the prevertebral fascia of the deep surface of the cervical vertebrae (prevertebral space), consisting of the upper, middle, and lower sympathetic ganglia and the intergranular branches. The upper cervical ganglion is the largest, pike-shaped, and is located anterior to the C2-3 transverse process. The middle cervical ganglion is located anterior to the transverse process of the 6th cervical vertebra. The lower cervical ganglion is often combined with the T1 ganglion to form a stellate ganglion, which is located anterior to the 1st ribcage. All three ganglia give off cardiac branches that enter the thoracic cavity and participate in the formation of the cardiac plexus. Cervical PVB should not be performed with simultaneous bilateral blocks, as this may cause adverse cardiac reactions. Distribution of spinal nerves in the cervical segment. The posterior cervical branch of the C1 nerve is shorter, branching off from the trunk on the inferior side of the vertebral artery and traveling backward into the occipital triangle, mainly distributing in the upper trapezius, posterior rectus of the head, and lower trapezius of the head, etc. The posterior branch of the C2 nerve is located between the posterior atlantoaxial arch and the pivot plate, and passes out of the lower side of the lower trapezius of the head, with the lateral branch innervating the head longissimus dorsi muscle, the pincer muscle, and the head semispinalis muscle. The medial branch innervates the greater occipital nerve.The posterior branch of C3 travels posteriorly around the C3 articular eminence and distributes in the neck, innervating the trapezius muscle.The posterior branch of C4 distributes in the shoulder, innervating the trapezius muscle.The C5-T1 nerve distributes throughout the upper extremity.The C5-6 innervates the deltoid muscle, o biceps muscle.The C6-8 innervates the o biceps muscle.The C6-7 innervates the anterior rounded muscle of the spinning front, and the C6-8 innervates the weight of the weight of the muscle, ‘weight of the weight of the weight of the strainer’.The C8-T1 innervates the interosseous muscle and the thumb to the palmar muscles. The above nerve injury, can cause the corresponding part of the pain symptoms. Thoracic spinal nerve distribution is relatively simple than the cervical nerve. The thoracic spinal nerve passes through the intervertebral foramen to the paravertebral area and immediately divides into the anterior and posterior branches. The anterior main branch constitutes the intercostal nerve, which travels between the posterior intercostal membrane and the intrathoracic fascia and adjacent pleura, and gives off a lateral cutaneous branch at the costal angle. The anterior and paravertebral spaces of the thoracic vertebrae consist of loose connective tissue between the spinal column and the pericardial and pleural wall layers, in which many important structures are located. For example, the intercostal artery, which originates from the aortic thorax, is accompanied by the eponymous vein and the intercostal nerve. On the left side of the mediastinum, the thoracic aorta is a continuation of the aortic arch, which begins on the left side of the inferior border of the fourth thoracic vertebra, travels down the spine to its left, then gradually moves forward inward and travels along the median line anterior to the spine, and the inferior border of the twelfth thoracic vertebra crosses the diaphragmatic aortic fissure for the continuation of the abdominal aorta. Below the lateral aspect of the thoracic aorta is the hemichordate vein; above it is the parachordate vein, which collects venous blood from the left intercostal space, and the left thoracic sympathetic trunk is located posteriorly and laterally to the hemichordate vein. On the right side of the mediastinum, the singular vein collects blood from the right intercostal vein, which ascends along the right side of the thoracic vertebral body to the height of the fourth thoracic vertebral body and injects into the superior vena cava. Between the singular vein and the thoracic aorta is the inferior thoracic duct. Lateral to the singular vein and affixed to the right side of the spine is the right thoracic sympathetic trunk. It consists of a locally expanded thoracic sympathetic node and its inter-nodal branches. The upper segment is anterior to the head of the ribs and the posterior intercostal vessels, and the lower segment gradually moves inward to the sides of the vertebrae. There are 10-12 sympathetic ganglia on each side, and fibers emanating from thoracic sympathetic ganglia 6-9 form the great visceral nerve, which passes through the diaphragm to finally reach the celiac ganglia. The 10th-11th thoracic sympathetic ganglion sends out fibers that make up the small visceral nerve, which passes through the phrenic pedicle and finally the aortic-renal ganglion. The sympathetic trunk ganglia are connected to the corresponding spinal nerves by gray and white traffic branches. The anterior branches of the lumbar nerves are progressively thicker from top to bottom. The anterior branches of the 1st-4th lumbar nerves form the lumbar plexus. Another part of the 4th lumbar nerve and the 5th lumbar nerve form the lumbosacral trunk, which then forms the sciatic nerve with the sacral plexus 1-3. The lumbar plexus is located behind the retroperitoneal psoas major muscle, anterior to the transverse process of the lumbar vertebrae, and on the medial border of the lumbar square muscle. The lumbar paravertebral anatomy relates to and consists primarily of the spine with its surrounding muscles. Sacrospinal muscle, also known as the erector spinae muscle, is located on both sides of the longitudinal ridge of the spinal process of the spine, starting from the occipital bone, and arriving at the sacrum of the long muscles. The psoas major muscle is located on both sides of the lumbar spine, the upper part is located in the medial side of the psoas rectus muscle, the middle part is located in the medial side of the iliopsoas muscle, from the thoracic 12, lumbar 1-4 vertebrae and the lateral side of the intervertebral discs, as well as all the transverse lumbar vertebral protrusions. The psoas muscle begins at the iliac crest and ends at the thoracic 12 ribs and the transverse processes of the lumbar 1-4 vertebrae. As far as the anatomical relationship of the lumbar PVB puncture target is concerned, it is located on the lateral aspect of the intervertebral foramen between the two vertebral plates, which are anteriorly and posteriorly located by the lumbar major and sacrospinal muscles, respectively, and laterally by the lumbarfontalis muscle [5-6]. The plane of the intervertebral space that intersects with the lateral aspect of the intervertebral foramen of either the cervical, thoracic or lumbar segments is the puncture target of PVB. Third, the puncture technique PVB technical operation generally requires the anatomical relationship between the spinous process and the vertebral plate as the puncture needle entry point, and the spinous process should be identified and labeled first. Cervical lateral approach paravertebral block technique. The patient is placed in the supine position with the head turned to the healthy side and a thin pillow under the upper thoracic and cervical vertebrae to accentuate the cervical spine. The operator first identifies the posterior nodes of the C3-7 transverse processes, but they are not easily palpable in overweight patients. A straight line was drawn between the mastoid process and Chassaignac’s (posterior C6 transverse process) node, and another straight line was drawn 0.5 cm behind this line. Since the C2 transverse process is not easily accessible, the second line can be positioned 1.5 cm caudal to the tip of the mastoid process, and the tip of each transverse process can be moved caudally by approximately 1.5 cm. In patients with tall stature and long transverse processes in the back of the neck, the distance between adjacent transverse processes can be up to 1.7 cm or even 2.0 cm.To determine the post-transverse node through which the blocking nerve passes, make a mark, routinely disinfect the skin, lay a sterile towel, and subcutaneously inject local anesthetic dermatomes into the anterior edge of the determined post-transverse node. The skin was secured with the left finger, and a 5-cm 7# needle was inserted medially and caudally until the anterior margin of the nerve or post-transverse node was touched, with an insertion of 2-2.5 (however, 3-4 cm was sometimes required for patients with excessive obesity). Eliciting a slight sensory abnormality or using a nerve stimulator can confirm the nerve, and if anesthesia is administered, 5-7 ml of local anesthetic can be injected. 2 ml of local anesthetic can also block this segment of the spinal nerve if the tip of the needle is on the surface of the nerve (not in the radicular canal). If it is for pain management, it is often necessary to block 3-4 adjacent spinal nerves at the same time. 2-3 ml of local anesthetic is injected into each posterior node of the transverse process or a single puncture needle is used to inject a total of 5-7 ml of therapeutic fluid into several segments. Posterior cervical approach paravertebral block technique. The patient is placed in a lateral position with a pillow under the head and the neck flexed. Determine the blocked nerve spine, and make a mark 3cm beside the spinal midline. Routinely disinfect and spread the treatment towel, and make a dermatome on the mark. The 12cm long 7# needle with a depth marker was inserted vertically into the skin and continued to advance slightly inward until it touched the bone-like sensation of the vertebral plate, and the marker on the body of the needle was retreated to a distance of 1cm from the skin. The tip of the needle was retreated to the subcutaneous area, and the tip of the needle was slightly deviated outward so that the tip of the needle was stabbed again along the lateral edge of the vertebral plate until the needle marker touched the skin. The needle continues to be inserted slowly until there is a sense of resistance, suggesting that the tip of the needle has been located in the external port of the intervertebral foramen, and this puncture may not elicit sensory abnormalities, but the tip of the needle must be inserted into the paravertebral space. This interspace is connected to each other in the cervical region, which allows the drug to spread to the neighboring ganglion. Each segment is injected with 3-4 ml of local anesthetic, and if 3-4 segments are blocked, 9-12 ml are injected. therapeutic block is best accomplished under the guidance of an imaging monitor. Chest PVB technique operation technique. This operation is best performed under an image monitor. After determining the block site spinal protrusion and routinely sterilizing and spreading the therapeutic towel, a dermatome is made with local anesthetic at the tip of the thoracic spinous process at a 1.5cm-2.0cm paracentral opening. The local anesthetic can block to the lateral upper part of the vertebral plate. A 12-cm long 7# puncture needle with depth markers was inserted vertically into the skin until the tip touched the lateral aspect of the vertebral plate, and then the needle was retreated subcutaneously, moved outward by 0.5 cm, or angled outward by 50-100, and inserted again along the lateral edge of the vertebral plate until the tip of the needle exceeded the lateral edge of the plate, and then punctured into the ligament of rib and transverse processes between the upper and lower edges of the transverse process of the vertebral body. If the tip of the needle is felt to have penetrated this ligament, a syringe with 2 ml of saline is attached to the end of the needle and a sense of resistance is felt when trying to inject the saline. At this time, the left hand slowly into the needle, the right hand continues to push the syringe core, the tip of the needle into the ligament while experiencing the resistance of pushing saline into the needle. Once the tip of the puncture needle penetrates the crib-transverse ligament and enters the paravertebral region, the right hand immediately feels that the resistance disappears. Aspiration is free of blood or CSF and the solution can be injected. It should be noted that the spinous processes localized in the paraspinal space punctured are those of the previous vertebra. Lumbar PVB technique operation. After determining the lumbar spinous processes, routinely sterilize and spread the treatment towel. A dermatome was made 2cm-2.5cm from the spinous process, and a 12cm long 7# puncture needle with depth markers was used to puncture vertically, touching the lateral part of the ipsilateral vertebral plate all the way to the lateral part of the vertebral plate. Once the vertebral plate is touched, the depth marker on the body of the needle is moved to 1cm-1.5cm from the skin. The needle is withdrawn and moved outward 0.5 cm, and the needle is again advanced along the lateral margin of the vertebral plate for 1.5 cm, or all the way beyond the plate, when the depth mark of the puncture needle just touches the skin and the tip of the needle is located in the external foramen of the intervertebral foramen. Despite the thickness of the lumbar nerve, standardized operation is difficult to touch and induce nerve radiolucent anisotropy, and the drug can be injected when there is no blood or CSF in the aspiration. Some scholars have reported the use of pressure method to determine the localization method of thoracic paravertebral space. There was at least a 10% failure rate due to the use of conventional air or saline resistance disappearance to determine the paravertebral space. The authors, treating 14 conscious adult patients suffering from thoracic pain, determined the following results on the patients via erector spinae puncture. Mean inspiratory pressure (29.5±14.2 mm Hg) exceeded mean expiratory pressure (19.4±9.7 mm Hg) before the needle crossed the costo-transverse ligament. However, the resistance suddenly disappeared after the puncture needle passed through the wider costo-transverse ligament, and at the same time, the mean expiratory pressure (7.6±3.7 mmHg) exceeded the inspiratory pressure (3.3±2.9 mmHg), and no negative pressure was recorded. The results of this puncture are important for improving the success rate of thoracic paravertebral analgesia. Recently, Klein et al. reported that 5 ml of local anesthetic was injected into each intervertebral space of the thoracolumbar joint block (T10-L2). 15-30 minutes later, the inguinal range of the plane of anesthesia could be seen, and the duration of the block was more than 10 hours in most patients. The results showed that multispaced paravertebral injection of local anesthetic not only produced effective analgesic effect, but also sustained analgesia for a longer period of time without side effects. The authors also measured the range of sensory plane regression on both sides of 52 patients with low back and leg pain 10 minutes after L3-4 paravertebral injection of 0.5% lidocaine 15 ml. The results confirmed that the range of ipsilateral and contralateral sensory planes after the block was reduced to T7.12±1.77~L3.5±0.97 and T11.20±4.94~L2.6±0.96, respectively, which indicated that lumbar paravertebral block with 15 ml of 0.5% lidocaine could produce different degrees of sensory planes reduction on both sides. This may be related to the fact that the drug of PVB can enter the epidural space through the intervertebral foramen, so the treatment of lumbar radiculitis pain with PVB can also produce the efficacy of epidural block.