Spinal anesthesia

Spinal anesthesia can be a method of choice for many operations below the level of the navel, such as hernia repair, gynecological and urological operations, interventions on the perineum or genitals. Under spinal anesthesia, it is possible to perform any operation on the lower limbs. An exception can be only amputation, since the presence of a patient in such an operation is regarded as a serious psychological trauma. In a similar situation, a combination of spinal anesthesia with superficial anesthesia is possible. Spinal anesthesia is particularly beneficial in older patients with chronic bronchial obstructive diseases, diabetes mellitus, hepatic, renal and endocrine disorders. Vasodilatation accompanying anesthesia can have a beneficial effect in many patients with moderate heart failure, with the exception of patients with predominant stenosis of the heart valves or those suffering from severe arterial hypertension. Spinal anesthesia can be used in patients with traumatological profile, provided adequate replenishment of the circulating blood volume. In midwifery, it is an ideal tool for anesthetic maintenance of manual removal of placental residues provided that there is no hypovolemia. There are certain advantages in using it for anesthesia of a caesarean section, for both the mother and the baby.

[1], [2], [3], [4]

Spinal anesthesia: indications

Spinal anesthesia is indicated in operations below the level of the navel (for example, hernia repair), gynecological and urological operations, any interventions on the perineum, genitals and lower extremities.

Puncture level

Spinal anesthesia involves the administration of a small dose of local anesthetic directly into the cerebrospinal fluid. Puncture is performed at the level of the lumbar spine below the level of the end of the spinal cord L2.

Reference point:

The line connecting the vertices of the crests of the ilium bone corresponds to the boundary of L3-L4. The level of spinal anesthesia depends on the dose, the specific gravity of the solution and the patient's position.

Anatomy

The spinal cord usually ends at the level of L2 in adults and L3 in children. Puncture of the dura mater above this level is associated with a slight risk of spinal cord injury. An important reference point - the line joining the tops of the iliac crests, runs at the level of L4 - L5. The anatomical structures through which the needle passes through to the preparation of cerebrospinal fluid are skin, subcutaneous tissue, supraspinal ligament, interstitial ligament, yellow ligament, dura mater, arachnoid membrane. A local anesthetic injected into the subarachnoid space mixes with the cerebrospinal fluid and quickly causes a blockage of nerve roots that it can reach. Distribution of local anesthetic within the spinal space is influenced by a number of factors - the specific gravity or baricity of the local anesthetic, the position of the patient, the concentration and volume of the injected solution, the level of puncture and the rate of injection.

Preoperative preparation. High spinal anesthesia causes significant physiological changes, primarily on the part of the circulatory system, which makes it necessary to ensure proper monitoring and preoperative preparation. The patient should be familiarized in advance with the technique of the forthcoming spinal anesthesia. It is important to explain that spinal anesthesia blocks the pain, while maintaining a certain level of tactile sensitivity in the relevant area, which should not create discomfort. It should be painfully prepared for the manifestation of motor and sensory blockade in the lower extremities. If there is a feeling of pain, a transition to general anesthesia is possible. In the use of a specific premedication is usually not necessary.

If the patient is anxious, it may be sufficient to prescribe benzodiazepine drugs (diazepam in a dose of 5-10 mg per os) on the eve of the operation. It is possible to use drugs of other pharmacological groups, in particular drugs, in the appointment of anticholinergics (atropine, scopolamine) is usually not necessary.

In all patients who are scheduled for spinal anesthesia, it is necessary to ensure good intravenous access. Intravenous catheters of large diameter are used to ensure the introduction of a sufficient volume of fluid before anesthesia. The volume of fluid used depends on the age and height of the blockade. Infusion in a volume of at least 1000 ml can be used in all patients with high spinal anesthesia. Caesarean section requires about 1500 ml.

[5], [6], [7], [8], [9]

How is spinal anesthesia performed?

Perform lumbar puncture easier with the maximum flexion of the lumbar spine, setting the patient on the operating table and substituting under his feet a stool of the required height. Using forearms on the hips, the patient can maintain this position without tension for a long time. To provide additional comfort on your knees, you can put a roller or cushion of the appropriate size. Lumbar puncture can be performed in the supine position on the side with maximum bending of the legs in the knee and hip joints ("head to the knees"), which ensures maximum discrepancy of the spinous processes and facilitates access to the puncture site. For the convenience of the patient and the anesthetist, the assistance of an assistant may be required. Seated position is preferable in obese patients, lying - in patients with mental disorders or deep sedation. In addition, the consequences of the rapid development of hypotension or cardiodepressive vagal reflexes in a patient in a sitting position should be considered. An anesthesiologist who carries out the blockade takes a sitting position to ensure a stable position during the blockade.

What equipment does spinal anesthesia use?

• a set of sterile diapers and gauze napkins;
• needle for spinal puncture with a diameter of 24-29 gauges;
• 5-ml syringe for anesthetic injected into the spinal canal;
• 2 ml syringe for infiltrating the skin at the point of injection of the needle;
• a set of needles for anesthetic sampling and skin infiltration;
• a set of antiseptic solutions for skin treatment (chlorhexidine, alcohol);
• Sterile gauze balls for skin treatment;
• adhesive plaster for fixing the bandage at the point of injection of the needle;
• solution of local anesthetic for intrathecal administration.

A necessary condition - a solution of a local anesthetic suitable for intrathecal administration is packaged in one-off packages. In bottles containing several doses, preservatives are added, which can cause damage to the spinal cord when injected into the cerebrospinal fluid.

• a safety kit for equipment and medicines for general anesthesia;
• a set of equipment and medicines for cardiopulmonary resuscitation.

Lumbar puncture technique

The skin of the back of the patient is treated with an antiseptic (ethanol). Repeat the procedure several times, changing the gauze ball, hack to handle a large enough surface.

After the antiseptic has dried, a suitable interstitial space is localized. A patient with a pronounced layer of fatty tissue may need a significant effort to palpate it. At the site of the proposed injection, a small amount of a local anesthetic is injected subcutaneously with a 2 ml syringe and a thin needle for analgesia. Then the needle with the mandrel for anesthesia produces a puncture of the infiltrated skin and strictly along the middle line the needle is advanced between the spinous processes with a slight inclination downwards (5-10 °), in the middle thoracic region the angle of inclination of the needle can be 50-60 °. The needle is advanced to the yellow ligament, during which the resistance is felt, after reaching the epidural space, there is a feeling of failure, which can occur again at the time of passage of the dura mater. If the tip of the needle is in the correct position, after removing the stiletto should appear spinal fluid. If the needle rests against the bone, pull it 1 cm, making sure that it is on the middle line and try to hold it by increasing the angle of inclination in the vertical plane. When using a thin needle (24-25 gage), you need to wait 20-30 seconds before the spinal fluid appears. If cerebrospinal fluid is not obtained, insert the mandrel back into its original position and hold the needle a little deeper.

After receiving the cerebrospinal fluid, not having displaced the needle, attach the syringe to the local anesthetic. It is best to fix the needle by holding its pavilion between the thumb and forefinger of the free hand, firmly resting the back of the palm on the back of the patient. The needle pavilion is securely connected to the syringe, the hyperbaric solution has a high viscosity and a high pressure is required to inject it through the thin needle. Aspirate a small amount of cerebrospinal fluid to ensure that the needle is in the correct position, then slowly inject a solution of the local anesthetic. After the end of the injection, remove the needle, the conductor and the syringe as one unit and fix the sterile dressing with a plaster at the injection site.

It is possible to perform a lumbar puncture from two approaches: median and paramedical.

The median access described above is a technique of choice, since it assumes the evaluation of the projection of the needle in only two anatomical planes. At the same time on its way lie relatively anatomically poor vessels. In the event that moving the needle along the middle line is difficult, a possible alternative is paramedical access. He does not require the same level of cooperation with the patient and deep flexion of the spine in the lumbar spine.

Paramedical access involves inserting a needle at a point approximately 1 cm lateral to the midline and 1 cm below the palpable lower edge of the apex of the spinous process of the superior vertebra. Before the introduction of a needle or a conductor, infiltration anesthesia of the skin and deeper lying tissue is performed. The needle is inserted at an angle of approximately 10-15 ° with respect to the sagittal and horizontal plane as shown in Figure 17. The most common mistakes are inserting the needle too far from the midline and excessive deflection of it in the cranial direction. Nevertheless, when meeting with the bone, it is recommended to slightly tighten the needle and slightly increase its angle in the cranial direction. If, after that, contact with the bone again occurs, but at a deeper level, the inclination of the needle again slightly increases so as to bypass the upper edge of the arch of the underlying vertebra.

As with the use of medial access, a characteristic sensation can occur when the needle passes through the yellow ligament and the dura mater. However, because of the oblique position of the needle, they meet at a greater depth. After obtaining cerebrospinal fluid, spinal blockage is performed similarly to that with median access.

Choosing a local anesthetic

Theoretically, any local anesthetic can be used in a procedure such as spinal anesthesia. According to the duration of the action after the introduction into the spinal canal, all anesthetics can be divided into two groups: with a short 1-1.5 hours (lidocaine, mepivacaine, chlorprocarin) and an average of 1.5-3 hours, duration of action (bupivacaine, ropivacaine). The duration of action depends on the total dose. In addition, drugs that use spinal anesthesia are divided according to their specific density with respect to cerebrospinal fluid. They can be hyperbaric, that is, they have a greater specific density than the cerebrospinal fluid, isobaric or hypobaric. Since the specific density of cerebrospinal fluid is not high - about 1.003 at 37 ° C, it is impossible to prepare a solution that would be much lighter than it. Therefore, iso- and hyperbaric solutions are often used in practice. Hyperbaric solutions are prepared by adding 5-9% glucose, giving a specific density at the level of 1,020-1,030. They are subjected to the action of gravity and are worse mixed with cerebrospinal fluid. Isobaric and hyperbaric solutions can cause a reliable reproducible blockade. Using a hyperbaric solution and then changing the patient's position makes the spinal anesthesia the most manageable. In practice, the following preparations are most often used:

Lidocaine is available as a 5% solution, the hyperbaric solution is prepared on 7.5% glucose, its dose is 1-3 ml. Also 2/4 isobaric solution is used in the volume of -3-6 ml. Addition of 0.2 ml of adrenaline 1: 1000 to lidocaine can increase the duration of its action. Recently, there has been concern about the safety of a 5% lidocaine solution, in particular its neurotoxicity. Bupivacaine is used as a 0.5% hyperbaric solution in 8% glucose (2-4 ml dose) and 0.5% isobaric solution, as well as 0.75% hyperbaric solution at 8.25% glucose (dose 1-3 ml).

Since the introduction of an anesthetic with spinal anesthesia is performed only at the lumbar level, the spread of the blockade is determined by the amount of the injected solution, its concentration, specific gravity and the position of the patient after injection, rather than the level of the intervertebral space on which the puncture is performed. Large volumes of concentrated anesthetic will cause a deep blockade on a large extent. After the introduction of a small amount of hyperbaric solution, provided that the patient remains some time in the sitting position, you can get a classic "sciatic block", which extends only to the sacral spinal segments.

The rate of introduction of the solution has little effect on the final distribution of the blockade. Slow administration is combined with a more predictable spread of anesthetic, whereas rapid administration creates additional currents in the cerebrospinal fluid, which can cause unpredictable results. In addition, the increase in intra-abdominal pressure due to any cause (pregnancy, ascites, etc.) causes swelling of the epidural veins, compression of the dural sac and a decrease in the volume of cerebrospinal fluid, while the same amount of local anesthetic will cause a higher level of spinal anesthesia. Regardless of the position of the patient during the puncture and the initial level of the block, the spread of the blockade may change along with the position of the patient's body within the next 20 minutes after the introduction of the hyperbaric solution.

[10]

The dynamics of the blockade

In many cases, patients can not accurately describe their feelings, so it is reasonable to rely on objective signs. So, if the patient can not tear his foot off the surface of the bed, the blockade extends to at least the middle lumbar segments. It is not necessary to investigate sensitivity with the help of an acute needle, leaving a number of bleeding point wounds. It is better to determine the loss of temperature sensitivity with a tampon moistened with alcohol or ether. Assess the feeling of cold on the arm, the surface of the chest, where the sensitivity is not disturbed. Then examine the cutaneous surface of the leg, abdomen. Let the patient indicate the level at which he begins to feel the cold from touching. If the patient finds it difficult to give a definite answer, the pain sensitivity can be checked by gently pinching the skin with a vascular clamp. Using this method, it is easy to assess the degree of blockade. Do not evaluate the tactile sensitivity. Patients and surgeons should be warned that with a successful blockade, a sense of touch may persist, but there will be no pain sensitivity.

If, 10 minutes after the injection of the local anesthetic solution, the muscle strength of the lower limbs and the normal level of sensitivity remain intact, the blockade failed, most likely due to the fact that the anesthetic solution was not injected intrathecally. Try again.

In the case of a one-sided blockade or an insufficient height of the block on one side, when the hyperbaric solution is used, put the patient on the side with insufficient blockage for a few minutes and lower the head end of the table. If an isobaric solution was used, put the patient on the side that should be blocked (any turn of the patient during the first 10-20 minutes after the injection of a local anesthetic helps to increase the blockade level).

If the level of the block is not high enough (when using hypertonic solution), lay the patient on his back and lower the head end of the table so that the anesthetic solution can bypass the lumbar spine of the spine. To make more flat lumbar lordosis it is possible, asking the patient to bend his legs in the lap. When using isobaric solution, turn the patient all 360 degrees (on his side, then on his stomach, on the other side and again on his back).

If the block is too high, the patient may complain that it is difficult for him to breathe and / or tingling in his hands. You do not need to raise the head end of the table.

If nausea or vomiting occurs, which may be one manifestation of a high block or arterial hypotension, measure blood pressure and act according to the result.

Care must be taken to control breathing, heart rate and blood pressure. After the blockade develops, blood pressure may drop to a critical level, especially in elderly patients with hypovolemia.

Clinical signs of hypotension are pallor, cold sweat, nausea, vomiting, a sense of anxiety and general weakness. Moderate hypotension is quite acceptable when in young trained people systolic blood pressure is reduced to 80-90 mm Hg, in the elderly - 100 mm Hg. And if the patient looks and feels well and breathes adequately. Bradycardia can also take place, especially when the surgeon works on the intestine or on the uterus. If the patient feels well-the arterial pressure is maintained within acceptable limits, there is no need to use atropine. When the heart rate drops below 50 per minute or hypotension develops, intravenously inject 300-600 micrograms of atropine. If this is not enough, you can use ephedrine.

In a number of cases, shaking may occur, in such a situation, soothe the patient and give him oxygen through the mask. Inhalation of oxygen through the face mask at a rate of 2-4 l / min is a common practice in spinal anesthesia, especially if sedation is used.

Surgical intervention always causes a stressful reaction from the patient, even if the pain is completely blocked by successful spinal anesthesia. Most patients need additional sedation. The optimal level, which is not so easy to determine, because too deep sedation, may be the cause of hypoventilation, hypoxia, or unnoticed regurgitation of gastric contents. As a rule, a sedated patient should easily awaken and retain the ability to maintain verbal contact. In case spinal anesthesia is inadequate, it is much better to selectively use drugs for general anesthesia and monitor airway patency than resort to high doses of benzodiazepines and opiates.

In the early postoperative period, as in the case of general anesthesia, the patient needs constant careful monitoring of vital functions. He must be transferred to an office where monitored monitoring is available and there is always a trained medical staff able to provide emergency assistance in case of complications. This may be an awakening ward or an intensive care unit. In case of hypotension, the sister should raise the foot end of the bed, give oxygen, increase the speed of intravenous infusion and invite the responsible doctor. It may be necessary to introduce additional vasoresurs, an increase in the volume of the injected fluid. The patient should be familiar with the duration of the blockade, he should be clearly instructed about the need not to try to stand up until the strength of his muscles is fully restored.

Spinal anesthesia for caesarean section

Currently, spinal anesthesia is recognized throughout the world as a method of choice for cesarean delivery. Spinal anesthesia has significant advantages over the general procedure for cesarean delivery and combines simplicity, speed and reliability. It is devoid of such formidable complications, which are the main causes of anesthesia mortality in obstetrics, such as aspiration of gastric contents with the development of Mendelssohn syndrome and difficulties in tracheal intubation, accompanied by hypoxia. Such a wide use of regional anesthesia is explained by the fact that the calculated risk factor for lethal complications with general and regional anesthesia is 17: 1. In the UK, amid an increase in the frequency of deaths from 20 cases per 1 million cesarean sections in 1979-1984. Up to 32 in 1985-1990. There was a decrease in their incidence among those operated under spinal anesthesia from 8.6 to 1.9 cases. In addition, spinal anesthesia has a more favorable effect on the state of newborns compared with general anesthesia. Children born on a background of spinal anesthesia do not receive sedatives through the placenta and are less susceptible to respiratory depression. Assessment of the state of newborns on Apgar scale after cesarean section under regional anesthesia is significantly higher than after operations under general anesthesia. At the same time, there are a number of objective difficulties. A pregnant woman is technically more difficult to perform spinal anesthesia because the enlarged uterus prevents flexion of the lumbar spine. If the birth activity has already begun, a woman will not be able to sit evenly during labor. Until spinal anesthesia began to use thin enough (25 geydzh) needles, the frequency of post-puncture headaches was unacceptably high. Spinal anesthesia should not be performed with caesarean section if the anesthesiologist does not have sufficient work experience.

In the absence of hypovolemia due to bleeding, spinal anesthesia can be a simple and safe method of anesthesia to manually remove placental residues from the uterine cavity, without causing relaxation.

Choosing a local anesthetic

Although the local anesthetic lidocaine continues to be actively used in the republic, it gradually loses its place to bupivacaine and ropivacaine due to the high degree of differentiation of the block, that is, when the concentration of the latter decreases, the motor block decreases, while maintaining a high level of analgesia.

[11], [12], [13], [14]

Technique of blockade

From a technical point of view, spinal anesthesia in a pregnant woman does not differ from that in general surgical practice, but it requires taking into account a number of factors. Usually, in pregnant women before conducting this anesthesia, it is recommended to perform an infusion preload with crystalloid solutions in a volume of at least 1500 ml or 500-1000 ml of hydroxyethyl starch preparations. After the infusion of the latter, the volume of circulating blood and cardiac output is higher, the frequency of arterial hypotension is lower, and the time for creating preload is much shorter, which is important in conditions of emergency situations.

Although spinal anesthesia is not contraindicated in preeclampsia of moderate severity, remember that preeclampsia is often combined with a lack of coagulation and relative hypovolemia. In addition, there is always the risk of sudden development of convulsive syndrome, which makes it necessary to prepare in advance a set of anticonvulsants (diazepam, thiopental).

Most preferable for puncture is the intervals L2-L3. To ensure cesarean section, the height of the block should reach the level of Thb (the level of the sternal base). In most cases, it is sufficient to administer local anesthetics in the following amounts, preferably using hyperbaric solutions: 2.0-2.5 ml of 0.5% bupivacaine hyperbaric solution, or 2.0-2.5 ml of 0.5% bupivacaine isobaric solution , or 1.4-1.6 ml of a 5% hyperbaric lidocaine solution, or 2.0-2.5 ml of an isobaric lidocaine solution with the addition of epinephrine (0.2 ml of the dilution solution at 1: 1000).

Mandatory monitoring of the following parameters: ADSI, ADDIAS, HR, BH, Sa02, cardiac fetal activity and uterine contraction.

Position of the pregnant patient

A pregnant patient should never be in a supine position, because a large uterus can squeeze the inferior vena cava under the action of gravity, to a lesser degree this applies to the aorta, which leads to menacing hypotension. It is necessary to ensure a sufficient inclination on the side, which can be achieved by tilting the operating table or by placing the roller under the right side. In this case the uterus deviates to the left and the lower hollow vein does not contract.

As in any other case, during the operation under spinal anesthesia, the patient should be inhaled oxygen using a face mask. If, in spite of the infusion preload, hypotension develops, you can use vasopressors, among which ephedrine is the choice, as it does not cause a spasm of the uterine vessels. In his absence, it is possible to use other vasopressors, since hypotension can seriously damage the fetus. After delivery, among the preparations of the oxytocin series, it is preferable to use synthocinone, since it to a lesser degree causes vomiting in comparison with the ergometrine.

Complications after spinal anesthesia

[15], [16], [17]

Infection

It occurs extremely rarely with strict adherence to asepsis rules.

Hypotension

It is the result of vasodilation and a functional decrease in the effective volume of circulating blood. Maternal hypotension can lead to a deterioration of blood supply to the myometrium, weakening of labor and intrauterine hypoxia of the fetus, which requires the immediate implementation of a number of measures:

1. Check the adequacy of the uterus shifting to the left (side slope of the operating table to the left or the roller under the right buttock, the minimum lateral slope should be at least 12-15 °).
2. All patients with the development of hypotension should adjust oxygen inhalation with a face mask until the blood pressure is restored. Raise your legs, thus increasing the venous return by lifting the lower part of the operating table. By tilting the entire operating table, you can also increase the venous return, but this will lead to the spread of the local anesthetic hyperbaric solution through the spinal canal, increase the level of the block and aggravate hypotension. If an isobaric solution was used, the slope of the table will not significantly affect the height of the block.
3. Increase the rate of intravenous fluid injection to the maximum until the arterial pressure is restored to an acceptable level.
4. If there is a sharp drop in blood pressure and there is no response to the infusion load, inject ephedrine intravenously, which causes a narrowing of the peripheral vessels and increases cardiac output due to the frequency and strength of myocardial contraction without reducing placental blood flow. Ampoule contents (25 mg) diluted to 10 ml with physiological solution and injected fractionally into 1-2 ml (2.5-5 mg), guided by the effect on blood pressure. It can be added to the vial with an infusion medium, while its effect is regulated by the rate of infusion or administered intramuscularly, however, the development of the i effect slows down. Perhaps a fractional administration of adrenaline (50 μg) or infusion of norepinephrine in appropriate dosages. If hypotension is maintained, vasopressors should be used immediately, with bradycardia administered atropine.

Headache after spinal anesthesia

One of the characteristic complications of spinal anesthesia is post-puncture headaches. They develop within a few hours after the operation and can last more than a week, usually localized in the occipital region, may be accompanied by rigidity of the neck muscles. Often associated with nausea, vomiting, dizziness, photophobia. Consider that their cause is associated with the outflow of cerebrospinal fluid through the puncture hole in the dura mater, the result of which is the tension of the meninges and pain. It is believed that needles having a small diameter (25 or more G) and a sharp point like a sharpened pencil, make a dia mater of a smaller diameter in the dura mater and can reduce the incidence of headaches compared to conventional needles with a cutting tip.

Patients suffering from a headache after such a procedure as spinal anesthesia, prefer to remain in a prone position. Previously it was believed that in order to prevent headaches, the patient should be kept in bed for 24 hours after spinal anesthesia. Recently, it is believed that this is not necessary, the patient can get up if there are no obstacles to the surgical plan.

Do not restrict them to liquids, if necessary, you can add it intravenously to maintain an adequate level of hydration. Simple analgesics such as paracetamol, aspirin or codeine can be useful in the same way as all measures that increase intra-abdominal and with it epidural pressure (turning on the stomach). Migraines can be effective, as well as beverages containing caffeine (coffee, coca-cola, etc.).

The delay of urination can take place, since sacral vegetative nerve fibers restore their function after spinal anesthesia among the latter. Overflow and painful overgrowth of the bladder may require it to be catheterized.

The total block develops swiftly and can lead to death, if in a timely manner is not recognized and resuscitation measures are not started. Spinal anesthesia is complicated by this condition relatively rarely, more often the result of an erroneous intrathecal injection of an anesthetic. Clinical manifestations of the total block: loss of sensitivity or weakness in the hands, shortness of breath and loss of consciousness. The algorithm for providing emergency care includes:

1. Activities of cardiopulmonary resuscitation.
2. Intubation of the trachea and mechanical ventilation with 100% oxygen.
3. Treatment of hypotension and bradycardia with intravenous infusion load, atropine and vasopressors. If treatment is not timely, a combination of hypoxia, bradycardia and hypotension can quickly lead to cardiac arrest.
4. Artificial ventilation, which must continue until the block is authorized, when the patient can provide the required volume of minute ventilation without assistance. The time that will be required for this will depend on which of the local anesthetics was administered and its doses.

Spinal anesthesia: consequences

It seems that the needle is in the right position, but cerebrospinal fluid does not appear. Wait at least 30 seconds, then try turning the needle 90 degrees and putting it again. If spinal fluid does not appear, attach an empty 2-ml syringe and inject 0.5-1 ml of air to ensure that the needle is not blocked, then slowly pull up the needle, constantly aspirating the contents with a syringe. Stop as soon as a spinal fluid appears in the syringe.

Blood was obtained from the needle. To wait a little, if the blood is diluted and there is a spinal fluid - everything is fine. If pure blood is allocated, most likely the tip of the needle is in the epidural vein and it should be moved a little further to reach the dura mater.

The patient complains of sharp stitching in the leg. The tip of the needle rests against the nerve root because the needle has moved laterally.

Tighten the needle and change its direction medial with respect to the damaged side.

Wherever the needle goes, it rests against the bone. Make sure that the patient is in the correct position, his spine is maximally bent in the lumbar region, and the point of needle insertion is located along the middle line. If you are not sure of the correct position of the needle, ask the patient from which side he feels the prick. If you have to deal with an age patient who can not bend his back enough or if his intercostal ligament is highly calcified, then paramedial access can be used as an alternative. To do this, insert the needle 0.5-1 cm lateral to the midline at the upper boundary of the underlying spinous process and direct cranial and medial. If, when moving the needle, it rests against the bone, then, most likely, it is the arch of the vertebra. Try, step by step moving along the bone, to reach the epidural space and through it puncture the dura mater. When using this technique, it is recommended to first anesthetize the muscles through which the needle is carried.

The patient complains of pain after spinal anesthesia and during the needle. Most likely the needle passes through the muscles along one side of the interstitial ligament. Tighten the needle and change its direction medial with respect to the side where the pain was felt so that the needle was in the middle line, or introduce a small amount of local anesthetic for anesthesia.