Intercostal nerve block

Blockade of intercostal nerves is quite simple and has a wide clinical application as an additional measure of anesthesia in the postoperative period and in fractures of the ribs. To a large extent, it facilitates respiratory care, facilitates expectoration of phlegm and a decrease in frequency after surgical complications.

[1], [2], [3], [4], [5]

Indications for blockade of intercostal nerves

Anesthesia in the postoperative period in operations on the upper abdominal floor, such as cholecystectomy using the Koherovsky incision, analgesia in the postoperative period with thoracic operations, analgesia in the fracture of the ribs, analgesia and muscle relaxation in thoracic operations in combination with general anesthesia.

The volume of local anesthetic - as a rule, anesthesia of several intercostal nerves is used, for each segment 2-3 ml of solution in a total dose of up to 20-25 ml is administered.

Anatomy

Intercostal nerves are formed from the ventral roots of the spinal nerves of the corresponding segment. They leave the paravertebral space and are sent to the lower border above the recumbent rib. First they are between the pleura in front and the intercostal fascia from behind, then penetrate into the space between m. Intercos talis internus and m. Intercostalis intimus. Here they are divided into two or more branches that run in the intercostal space and supply the muscles and skin of the thoracic and abdominal wall. At the level of the mid-axillary line, each intercostal nerve gives the lateral cutaneous branch, which supplies the skin of the posterolateral surface of the trunk. The upper six pairs terminate at the edge of the sternum, their branches innervating the skin of the anterior surface of the thorax. The lower six pairs extend beyond the border of the rib and supply the muscles and skin of the anterior chest wall. The lateral cutaneous branches penetrate the outer intercostal muscles and divide into the anterior and posterior branches, respectively innervating the lateral surface of the abdomen far beyond the straight muscles and back. Skin branches freely anastomose with each other, creating a wide zone of cross innervation. Nevertheless, most of the muscles and cutaneous surface of the abdominal wall can be anesthetized by the blockade of 6-12 intercostal nerves. Recently, the question is debated whether adjacent intercostal spaces are connected. At the beginning they are located between the pleura and the posterior intercostal fascia, there is nothing that could prevent the spread of the local anesthetic solution extrapleural, seizing several adjacent nerves. Even with lateral administration at the level of the angle of the ribs, the solution can reach the extrapleural space. Distribution of the solution is facilitated by fracture of the ribs, when it can enter even into the pleural cavity. These positions serve as the basis for introducing a large volume of local anesthetic from one point in the hope that this will allow the capture of several adjacent intercostal nerves. However, the spread of the solution is unpredictable and to achieve a guaranteed result it is better to introduce small volumes from several points.

The patient's position in the blockade of the intercostal nerves

1. On the back, if the blockade of the intercostal nerves is planned at the level of the mid-axillary line. This is the most convenient position. The hand rises so that its brush is under the patient's head. The head turns in the opposite direction.
2. On the side, if a one-sided block is planned at the angle of the ribs.
3. On the abdomen, with bilateral blockade of the intercostal nerves at the level of the angle of the ribs.

Landmarks:

• Ribs are considered from the bottom up, starting from the 12th;
• The corners of the ribs are located 7-10 cm lateral to the middle line from the rear;
• The middle axillary line.

Blockade of intercostal nerves depends on the clinical situation. If the ribs are broken, the anesthetic is proximal to the fracture site. In the case of blockade of intercostal nerves in large quantities for postoperative analgesia or in addition to general anesthesia, it is performed at the level of the angle of the ribs. This assumes the patient's position on his side or on his stomach, although the solution of the anesthetic easily spreads across the intercostal space by several centimeters in both directions. Therefore, the intercostal nerves, including their lateral branches, can dig easily blocked at the mid-axillary line when the patient is on the back.

[6], [7], [8],

How is intercostal nerve blockade performed?

Blockade of intercostal nerves does not depend on the level at which it is produced, the mid-axillary line or the level of the rib corner. To prevent puncture of the pleural cavity, the point of the needle should be as close as possible to the surface of the rib. The rib is held between the 2nd and 3rd fingers of the free hand. A needle connected to a syringe with a local anesthetic solution is inserted between the fingers and advances until it contacts the rib. The needle is directed toward the rib, deviating in a cefoidal direction at an angle to the surface of the skin at about 20 ° after the contact with the rib is obtained, the needle tip descends down the rib surface, bypassing its lower edge so that the needle maintains the previous angle of inclination. After this, the needle is inserted approximately 3 mm in the direction of the inner surface of the rib. At the time of puncture of the external intercostal fascia, a dip or "click" is felt. Then into the space between m. Intercostalis interims and m. Intercostalis intimus is administered 3 ml of a local anesthetic solution. Alternative blockade of the intercostal nerves is aimed at preventing puncture of the pleural cavity, is to insert the needle almost parallel to the surface of the chest

The choice of local anesthetic depends on the specific conditions. Blockade of intercostal nerves in large amounts causes a high concentration of anesthetic in the blood, which can lead to a systemic toxic reaction, requires careful consideration of the administered dose. Most often used; a solution of lidocaine with the addition of adrenaline 1: 200,000 or 0.5% bupivacaine as well as the addition of epinephrine to reduce the peaks; concentration in the blood plasma. The maximum dose should not exceed 25-30 ml.

Complications and prevention measures

Systemic toxic reaction is possible in the blockade of intercostal nerves in large numbers. Its prevention consists in taking into account the total dose administered, the use of anesthetics containing adrenaline, as well as in general measures, including aspiration sampling before each injection of the solution.

Pneumothorax can occur with occasional puncture of the inner pleura, against the background of fracture of the ribs may be a consequence of trauma. The possibility of such a complication should always be borne in mind when blocking the intercostal nerves. In doubtful cases, diagnosis is based on lung radiography data. Treatment depends on the volume and speed of air intake.

Blockade of intercostal nerves is rarely complicated by infection, provided that the rules of asepsis are observed.

Hematoma. Multiple needle introductions should be avoided and small diameter needles (25 gauss or less) should be used.

[9], [10]