Transcatheter block is one of the more practical clinical techniques that many hospitals and physicians are performing. However, the problem of how to perform it in a standardized way still plagues many clinicians, especially young doctors. In this article, we organize the common nerve blocks in pain medicine according to “Pain Diagnosis and Treatment” edited by Prof. Guanxian Tan, in order to facilitate pain physicians to perform nerve blocks more skillfully and standardized.
One other point needs to be clarified: since patients are fat and thin, and each patient’s condition is not exactly the same, there is no practical meaning in how many centimeters to paracentralize a certain point during the treatment. However, for the convenience of description and more intuitive, this paper still adopts the description of how many centimeters to open a certain point, but the actual work should be done to achieve specific analysis of specific problems.
I. Mechanism of action of nerve block therapy
1.Block the conduction pathway of pain: By blocking the sympathetic nerve of sensory nerve, the nerve conduction pathway of somatic pain and visceral vascular pain can be blocked to achieve the purpose of direct pain relief
2.Block the vicious circle of pain: When the cause of pain occurs in a certain part of the body, this pain is felt through the peripheral sensory nerves, posterior roots, posterior horn of the spinal cord, spinal thalamic pathway, thalamus, which transmits stimulation to the central gyrus. On the other hand, the local pain is generated through the spinal reflex pathway, causing excitation of the efferent nerves (motor nerves and sympathetic nerves) that innervate the impaired part, thus causing reflex muscle spasm and vasoconstriction, resulting in local ischemia and hypoxia and metabolic abnormalities, i.e. causing a vicious cycle of pain. Therefore, effective nerve block can block the vicious cycle and improve the pain symptoms.
3.Improve blood circulation By blocking sympathetic nerve, it can make the blood vessels in the innervated area dilate, increase blood flow, reduce edema, relieve visceral and vascular pain, and also relieve sympathetic tension.
4.Nutritional nerve By local injection of some nutritional nerve drugs, it can reduce nerve edema, make the nerve blood supply rich, nourish the nerve and restore the normal function of the nerve.
5.Anti-inflammatory effect In recent years, it is found that endogenous antibiotics are tiny proteins in leukocytes, and this substance cannot function when it is poor. The blood flow in the region increases after sympathetic ganglion block, thus making endogenous antibiotics increase, and play anti-inflammatory effect.
Second, the difference between nerve block and traditional closure
The traditional sense of closure does not pay attention to the protection of the tendon area, coupled with the massive application of hormones, which has left a very bad reputation in the minds of doctors and patients. In contrast, nerve block is a new technology that requires doctors to carry out according to scientific anatomical positioning and after strict training, and it has good clinical effect and little side effect, especially the development of B-ultrasound guided nerve block has made this technology more and more important. Therefore, there is an essential difference between nerve block and closure in the traditional sense.
Nerve blocks commonly used in the pain treatment process
1.Stellate ganglion block
(1) Indications: herpes zoster, phantom limb pain, burning neuralgia, migraine, etc. in the head and face, chest and back and upper limbs. Since this technique can also improve blood circulation to the head, face, chest and upper extremities, it is also effective in the treatment of Raynaud’s disease, scleroderma, cerebral vasospasm, and reflex sympathetic dystrophy.
(2) Anatomical positioning: The stellate ganglion consists of the inferior cervical sympathetic ganglion emanating from C3-C7 and the 1st lumbar sympathetic ganglion, also known as the cervicothoracic ganglion, which is located in front of the cervical eminence of the 1st rib and the root of the transverse process of the 7th cervical vertebra and receives the T1-T2 nerve.
(3) Operation steps: The patient is placed in a supine position with a thin pillow under both shoulders. Body surface positioning: The outer edge of the trachea is first palpated laterally along the superior clavicular border, then 2 cm up along the trachea and parallel to the outer edge of the trachea to palpate the arterial pulsation. The middle finger of the operator’s left hand pulls the sternocleidomastoid muscle and the carotid sheath laterally, and the tip of the middle finger is palpated to bony sensation and moved slightly outward to expose the puncture site after pressing inward against the outer edge of the trachea as far as possible.
Use a 3.5 cm long, 7-gauge short needle to gently enter vertically along the operator’s middle finger tip until the tip and bone, retreat the needle tip 1-2 cm, recover no blood, and inject 6-8 ml of anti-inflammatory analgesic solution. 2-3 minutes of observation and the appearance of ipsilateral Horner’s (Horner’s) sign indicates a successful block, but Horner’s sign can also be excluded as a successful block criterion in order to alleviate the patient’s discomfort.
(4) Complications and prevention: downward puncture is too deep to mistakenly inject local anesthetic into the vertebral artery causing loss of consciousness; local anesthetic is mistakenly injected into the subarachnoid space, causing respiratory and cardiac arrest; shallow needle entry and large amount of local anesthetic, blocking the recurrent laryngeal nerve causing hoarseness; puncture site is too high or the amount of drug is too large, blocking the phrenic nerve resulting in reduced abdominal breathing; the tip of the needle is too caudal, possibly puncturing the apex of the pleura or the tip of the lung, causing pneumothorax. It is strictly forbidden to perform bilateral stellate ganglion block at the same time.
2.Cervical paravertebral nerve block
(1)Indications: Treatment of cervicogenic pain, migraine, cluster headache, cervical radicular neuralgia, cervical herpes zoster and post-herpetic neuralgia, etc.
(2) Anatomical positioning: cervical paravertebral nerve block is only performed between C2-C7.
(3) Operation steps: There are 2 types of accesses for cervical paravertebral nerve block, one is the posterior-lateral access method and the other is the lateral access method. Postero-lateral approach: Take the affected side to the upward position. Body surface positioning: determine the spinal nerve to be blocked on a spinous process with a 6-8 cm paracentral opening. Under local anesthesia, a 10-cm No. 7 needle is used to puncture the spinal nerve. The needle is inserted slightly to the midline (5°-10°) and touches the posterior lateral aspect of the vertebral subtalar joint, the body of the needle is slightly retreated by about 1 cm, and then the needle is slowly inserted along the lateral edge of the subtalar joint, and the resistance to air injection disappears, suggesting that the tip of the needle enters the paravertebral space.
Inject 3-4 ml of analgesic and anti-inflammatory medication at each stage. the posterior approach should maintain a vertical puncture along the lateral aspect of the vertebral plate so that the vertebral artery is not lost. It is forbidden to enter the paravertebral opening at too large a distance, and the needle tip is biased medially into the needle after entry, which can easily damage the vertebral artery.
3.Thoracic paravertebral nerve block
(1)Indications: Used for intercostal neuralgia, postherpetic neuralgia, chest wall cancer pain and postoperative pain.
(2) Application anatomy: the thoracic spinal nerve enters the paravertebral space immediately after exiting the intervertebral foramen, and there is no direct connection between the paravertebral spaces. The drug is injected along the lax tissue at the bottom of the triangle of the intervertebral space in the near middle part, and it may spread up or down along this space.
(3) Operation steps: This operation is best performed under ultrasound guidance to prevent the occurrence of pneumothorax. The patient is placed in the upward position on the affected side, and a block gap needs to be extended above and below each other because the adjacent intercostal nerves communicate with each other. Positioning of the body surface: 2-3 cm next to the highest point of the spinous process of the thoracic spine, and the subsequent operation is the same as the cervical paravertebral nerve block. Note that the puncture needle should not penetrate the pleura and cause pneumothorax.
4.Lumbar paravertebral nerve block
(1) Indications: lumbar disc herniation or lumbar radicular neuralgia. Injection of nerve-destroying drugs has good effect on postherpetic neuralgia and peripheral cancer pain.
(2)(3)(4) Steps are omitted.
5.Supraorbital nerve block
(1) Indications: Applicable to supraorbital neuralgia, frontal herpes zoster pain, postherpetic neuralgia and cancer pain of this range.
(2) Anatomy of application: The supraorbital nerve emanates from the transcranial branch of the trigeminal nerve, proceeds anteriorly between the superior levator muscle and the orbital parietal wall, and is distributed to the eyelids and forehead via the supraorbital notch or supraorbital foramen, and its frontal branch fibers can extend to the cranial vault to communicate with the greater occipital nerve.
(3) Procedure: The patient is lying flat, and the supraorbital notch can be palpated at the inner 1/3 of the superior border of the affected box or in the middle of the eyebrow. The trigger point can be induced with the finger tip, and after routine disinfection, a short 3.5 cm long, 7-gauge needle is inserted 0.5 cm along the infraorbital foramen or incision, and 0.5-1 ml of anti-inflammatory analgesic solution can be injected when there is no blood in the retraction. orbital nerve block can also be done, and the needle tip is inserted 1.5-50 px along the top bone of the orbit, and 1 ml of 1% lidocaine + 0.5 ml of compound betamethasone can be injected when there is no blood in the retraction.
(4) Complications and their prevention: avoid conjunctival or corneal injury caused by disinfectant solution; the operator’s left index finger always protects the patient’s eye during puncture; the puncture should not exceed 50px, and 37.5px into the needle can be injected; the intraorbital block should not be injected with nerve-destroying drugs; if local swelling occurs, ice bags can be used for cold compresses.
6.Infraorbital nerve block
(1)Indications: Used for herpes zoster, post-herpetic neuralgia and cancer pain treatment in this nerve region.
(2) Application anatomy: the infraorbital nerve is the largest terminal branch of the direct continuation of the maxillary nerve emanating from the trigeminal nerve, which is called the infraorbital nerve after entering the orbit through the infraorbital fissure, and its branches include the lid branch, nasal branch, upper lip branch and buccal branch. The puncture point is located on the body surface by making a vertical line from the pupil in direct view to the ipsilateral external angle of the mouth, and then a line from the lateral union of the eyes (lateral canthus) to the midpoint of the upper lip, and the intersection of the two lines is the puncture point. The point of intersection of the two lines is the puncture point. Alternatively, a depression can be palpated directly with the finger under the infraorbital ridge, which is the infraorbital foramen.
(3) Procedure: The patient is placed in a supine position, routinely disinfected, and a 3.5-cm-long, 7-gauge needle is used to enter the infraorbital foramen via the infraorbital foramen. 2-2.5 cm of anti-inflammatory and analgesic solution of 1.5 ml is injected. 5 minutes of light pressure is applied to the puncture site after removal of the needle, and a band-aid is applied.
7.Maxillary nerve block
(1)Indications: maxillary neuralgia, acute herpes zoster pain, post-herpetic neuralgia, postoperative pain, cancer pain, post-radiotherapy pain.
(2) Application anatomy: The maxillary nerve is the second branch of the trigeminal nerve, which exits the skull from the anterior part of the trigeminal ganglion through the lower part of the lateral wall of the cavernous sinus through the foramen ovale. It branches out in the pterygopalatine fossa, including the ganglion branch (also known as the pterygopalatine branch), the zygomatic nerve branch, the infraorbital nerve branch, and the posterior branch of the superior alveolus. The branches in the infraorbital sulcus include: the middle branch of the superior alveolus and the anterior branch of the superior alveolus.
(3) Procedure: Take the affected side and lie in the upward position. Body surface positioning: The patient opens the mouth slightly, determines the midpoint of the zygomatic arch and the midpoint of the mandibular notch, and makes a line between the two midpoints, with 0.5 cm anterior to the line as the puncture point. After routine disinfection, a marked 10-cm-long, 7-gauge needle is used under local anesthesia to vertically advance the needle 3.5-4.4 cm to the outer plate of the pterygoid process, withdraw the needle 1 cm, adjust the angle of the puncture needle, and align the needle in the direction of the pupil.
Re-entry of the needle must not exceed the set depth marker. If the patient does not show a shock-like reaction, the tip of the needle can be used to do a fan scan until a shock-like reaction occurs in the upper teeth or upper lip, indicating that the tip of the needle reaches the maxillary nerve root. Backdraw no blood to inject 1-2 ml of 1% lidocaine. 3-5 minutes of observation, the patient’s pain is reduced, no other discomfort, and the therapeutic drug is injected. To avoid repeated punctures, a nerve localization stimulator can be used to more accurately determine where the puncture needle reaches the nerve trunk.
(4) Complications and their prevention: repeated injections of nerve-destroying drugs are not recommended to avoid local tissue atrophy;
8.Mandibular nerve block
(1) Indications: pain in the distribution area of each branch of the mandibular nerve, cancer pain, herpes zoster and post-herpetic neuralgia.
(2) Application anatomy: the mandibular nerve is the largest branch of the trigeminal nerve, consisting of most of the sensory nerve fibers and a slender motor nerve root fusion, from the foramen ovale out of the skull into the inferior temporal fossa, in the deep surface of the pterygoid muscle into the anterior and posterior trunks. The main branches are the auriculotemporal nerve (distributed in the skin of the temporal region and innervates the parotid gland), the buccal nerve (distributed in the skin and mucous membrane of the lateral wall of the mouth), the lingual nerve (distributed in the floor of the mouth and the mucous membrane of the anterior 2/3 of the tongue), and the inferior alveolar nerve (distributed in the mandibular teeth and gums, with its terminal branch piercing from the chin foramen and called the chin nerve, distributed in the skin and mucous membrane of the chin and lower lip.
The motor branch of the inferior alveolar nerve innervates the mandibular hyoid muscle and the anterior belly of the diastasis), the masticatory muscle nerve (a motor nerve, with branches of the occlusal nerve, the deep temporal nerve, the internal pterygoid muscle nerve, and the external pterygoid muscle nerve, innervating four masticatory muscles respectively)
(3) Operation technique: take the patient in upward lying position. Body surface positioning: same as maxillary nerve. When the needle is retreated to the subcutaneous, change the direction of the external auditory canal or the external posterior to re-enter the needle to the marker so that the tip of the needle reaches the external opening of the foramen ovale on the posterior side of the lateral plate of the pterygoid process, and the patient develops a mandibular click-like sensation, suggesting that the tip of the needle has touched the mandibular nerve trunk.
(4) Complications and their prevention: puncture bleeding: mostly seen in pterygoid conduction vein injury exiting the skull via the foramen ovale, also seen in middle meningeal artery injury exiting the sphenoid foramen posteriorly.
9.Glottopharyngeal nerve block
(1)Indication: linguopharyngeal neuralgia, tumor metastatic pain.
(2)Application anatomy: The linguopharyngeal nerve originates from the lateral aspect of the medulla oblongata and exits the cranium through the jugular foramen, together with the vagus nerve and the collateral nerve, forming the linguopharyngeal nerve stem ganglion. After exiting the cranium, it divides into a traffic branch to connect with the sympathetic ganglion, the auricular branch of the vagus ganglion, the vagus nerve and the facial nerve. Its main branches include the sinus nerve (distributed in the pressure receptors in the carotid sinus and chemoreceptors in the carotid body bulb), pharyngeal nerve (innervates pharyngeal mucosal sensation), tonsillar nerve (distributed in the upper part of the tonsils and the mucosa adjacent to the soft palate tonsillar nerve lingual branch (distributed in the posterior 1/3 of the tongue body and the lingual branch of the mucosa and anterior mucosa of the epiglottis)
(3) Operation technique: The patient is placed on the affected side in an upward-facing lateral position. Body surface positioning: determine as the anterior edge of the mastoid process, immediately below the external auditory canal as the puncture point, after routine disinfection, use 87.5px long, short No. 7 needle to pierce vertically about 2-62.5px, inject gas without resistance, draw back without blood, and inject anti-inflammatory and analgesic solution. For the treatment of cancer pain, inject 0.5-1ml of nerve-destroying drug. it is safer and more effective to operate under the guidance of CT 3D imaging.
(4) Complications and prevention: the injected drug may block the parasympathetic nerve or vagus nerve at the same time, occasional patients may experience tachycardia, the dose of injected local anesthetic should not be too much; the puncture is too deep may accidentally injure the internal jugular vein.
10.Hemilunar ganglion block
(1) Indications: trigeminal neuralgia, cancer pain in the region, facial herpes zoster, post-herpetic neuralgia, post-radiotherapy pain, intractable pain after gamma knife treatment or intracranial vascular decompression.
(2) Applied anatomy: The trigeminal ganglion contains two kinds of neurons, sensory and motor, and is emitted from the cerebral bridge, containing some sensory nerve fibers as somatic afferent fibers, which conduct pain sensation, position sensation, fine touch and nociception on one side of the face, and is the main nerve fiber of trigeminal neuralgia. A small portion of motor fibers originate from the trigeminal nucleus of the pons, which mainly innervates the masticatory muscles on one side and conducts the masticatory muscles proprioception. The eyes emanating from the trigeminal nerve exit the skull via the innervated supraorbital fissure, the maxillary branch via the foramen ovale, and the mandibular branch via the foramen ovale.
(3) The operation is usually performed under CT guidance. The patient is placed in a supine position with the head slightly tilted back. Body surface positioning: the intersection of the vertical line through the outer edge of the orbit and the horizontal line of the orofacial fissure, between the maxillary molars and the mandible at 3-4 cm lateral to the ipsilateral corner of the mouth, and the gap where the operator presses deeply with the finger is the entry point. The gap between the maxillary molar and mandible is the entry point.
When the needle was advanced to 4-125 px, the tip of the needle touched the bony sensation, suggesting that the tip of the needle reached the bone surface around the oval foramen. At this time, the direction of needle tip advancement was adjusted under imaging guidance until an electric shock-like or mandibular muscle contraction occurred, indicating that the tip of the needle reached the mandibular nerve near the oval foramen. After CT suggested that the needle tip entered the inner edge of the foramen ovale, no blood or cerebrospinal fluid was retrieved, and 1 ml of 1% lidocaine was injected, (used to exclude the puncture needle from entering the subarachnoid space or other tissues) and the patient showed hyperalgesia in one side of the trigeminal nerve distribution area after several minutes.
For patients with trigeminal neuralgia, radiofrequency treatment of the dorsal root ganglion can be taken, which can generally achieve better results, and the operation of puncture is the same as above.
11.Lumbar sympathetic nerve block
(1) Indications: It is used for the treatment of burning neuralgia of the lower limbs, phantom limb pain and diabetic peripheral neuralgia. Treatment of early vascular diseases such as Raynaud’s disease, vaso-occlusive vasculitis, ischemic lesions and frostbite of the lower limbs.
(2) Applied anatomy: The lumbar sympathetic nerve is located on the anterolateral side of the lumbar vertebral body, generally with four ganglia on each side, and is connected to the lumbar sympathetic trunk by interganglionic branches, superiorly to the thoracic sympathetic trunk, inferiorly between the anterolateral side of the lumbar vertebral body and the psoas major muscle, and posteriorly into the pelvis via the common iliac vessels, where it is connected to the pelvic sympathetic trunk.
(3) Operation steps: generally performed under CT guidance. Body surface positioning: The patient is positioned prone, the L2 spinous process is identified, and the puncture point and puncture access are determined under CT guidance. Under local anesthesia, a 300px-long, 7-gauge puncture needle is used to enter the needle along the route determined by CT guidance, and if the outer edge of the vertebral body is touched, the tip of the needle is then adjusted to reach the vicinity of the sympathetic nerve on the anterolateral side of the vertebral body. The contrast agent was injected, showing that the contrast agent was located on the anterolateral side of the vertebral body, the resistance to air injection disappeared, no blood was retrieved, 15-20 ml of local anesthetic was injected, and the patient felt a feverish sensation in the lower limbs after a few minutes. The same volume of anhydrous ethanol was injected. Maintain the original body position for 4-6h.
(4) Complications and their prevention: puncture too deep may accidentally injure abdominal organs or large blood vessels, and should be performed under CT guidance before and during puncture to avoid puncture injury as much as possible.
12.Suprascapular nerve block
(1)Indications: Treatment of pain around the shoulder joint, with manipulation for frozen shoulder.
(2) Anatomy of application: The suprascapular nerve is mainly composed of the upper part of the clavicle of the anterior branch of C5-C6 nerve fibers, starting from the upper trunk of the brachial plexus, passing through the oblique muscle and the deep side of the scapularis lingualis muscle to the scapular notch, then passing through the lower side of the transverse scapular ligament to the supraspinatus fossa, bypassing the scapular neck notch to the infraspinatus fossa. Along the way, branches are issued to the supraspinatus, acromioclavicular joint, acromioclavicular joint and infraspinatus.
(3) Operation technique: The patient is placed in a sitting position with the back facing the operator and the shoulders relaxed. Body surface localization: first identify the scapula and make a continuous line from the spinal edge to the acromion, both divided into two and three equal parts, with the anterior edge of the midpoint of the line between its midpoint and the outer 1/3, which is the suprascapular nerve puncture point. Under local anesthesia, a 250px-long, marked No. 7 puncture needle is used to enter the needle vertically to the suprascapular fossa. The needle is withdrawn by 25 px, and then the tip of the needle is tilted forward by 5°-10° into the needle, making a fan-shaped movement until a radiating sensation to the elbow appears. Withdraw no blood and slowly inject 5-8ml of anti-inflammatory and analgesic solution.
(4) Complications and their prevention: the needle should not be too deep, so as not to pierce the needle into the pleura. The use of B ultrasound guidance can reduce this complication.