RU2463086C2 - Method for sciatic nerve block from lateral approach - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely anesthesiology and neurology, and may be used in treating the patients suffering acute pain syndrome of lower extremities. For this purpose, a needle stick point is located on patient's back at 2-4 cm from a lower end of a greater trochanter along the line perpendicular to an extremity axis downwards from the most projecting portion. Then the needle 10-15 cm long is brought parallel to a plane of the operating table to verify its position with respect to the sciatic nerve. The verification of the needle position is stated by inducing paresthesia or muscular contractions by an electric nerve stimulator, or ultrasonography-assisted nerve visualisation. The absence of the verification enables the needle to be redirected in the fan-like direction in an axial plane at an angle 10-15°. If the prolonged block is required, a catheter is brought through the needle to perform analgesia for 2-6 days.

EFFECT: method provides ease of implementation with simultaneous reduction of a procedure time ensured by the use of one mark point for needle stick location and safe bringing.

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Description

The invention relates to medicine, more specifically to anesthesiology and intensive care, and can find application in the treatment of acute pain of the lower extremities.

Sciatic nerve blockade is indicated for:

- surgical, as well as traumatological and orthopedic interventions on the foot and the Achilles tendon;

- in combination with blockade of the femoral, obturator and external cutaneous nerve of the thigh for operations on the knee joint;

- in combination with blockade of the femoral, obturator, external cutaneous nerve of the thigh and superficial general anesthesia with mechanical ventilation during interventions on the hip joint;

- for postoperative analgesia for injuries and diseases of the foot and the Achilles tendon.

The following approaches for sciatic nerve block are known: posterior (classic), anterior, lithotomy, lateral (lateral).

A distinctive feature of each of these options is the way to determine the point of injection of the needle.

During anesthesia of the sciatic nerve from the posterior approach, a line is drawn connecting the posterior superior spine of the iliac crest and the greater trochanter of the femur. Then, from the middle of it, a perpendicular is marked, on which 4-5 cm are marked, and this point is the injection site. The results of a complete drug blockade from this access reach about 97%, which is ensured by the anatomical features of the passage of a nerve in this area and the presence of clear bone landmarks. The disadvantage of this method is the need to perform a blockade in the patient’s position on the side or abdomen, which is not possible to perform in case of fractures with fixation by skeletal traction or combined trauma (fractures of the pelvic bones, vertebrae).

Front access is as follows. A line is drawn connecting the anteroposterior iliac spine and the pubic tubercle. The second line runs parallel to the first, starting from the greater trochanteric femur and passing further in the medial direction. The upper line is divided into 3 equal parts and at the intersection of the medial and middle third, a perpendicular is drawn down. Its intersection with the bottom line is the point of injection. The technique does not require a change in the position of the patient’s body, but it is very painful (it forces the use of an additional volume of anesthetic for infiltration anesthesia), it is technically complex and, in general, has relatively low efficiency (≈40%) regardless of the qualifications of a specialist in the field of conduction anesthesia.

The lithotomy access is performed in the patient's position on the back, the leg on the side of the blockade is bent 90 ° in the knee joint and 90-120 ° in the hip. The needle is inserted perpendicular to the skin surface in the middle of the line connecting the greater trochanter of the femur and the sciatic tubercle until paresthesia appears. The blockade technique does not require active movements, thus being preferred for elderly patients, but has disadvantages that are identical with anterior access, including low efficiency and the need to bend a damaged limb.

The least traumatic and more comfortable for the patient is lateral access. However, this method is not sufficiently developed, as a result of which it is rarely used.

The present invention relates to this particular access.

A known method of plexus blockade of the lower limb from lateral access [patent RU 2240145 C1]. The needle is injected at a point 2-3 cm above the upper edge of the greater trochanter of the femur, the needle is inserted in the frontal plane perpendicular to the axis of the body to a depth until it contacts the surface of the body of the ilium wing until loss of resistance or the appearance of paresthesia; the anesthetic is injected between the sacrospinal ligament and piriformis muscle, then the subcutaneous tissue is infiltrated over theparticular ligament and parallel to the upper edge of the ilium wing. This technique allows you to anesthetize the limb up to the upper third of the thigh, but it is technically complicated and requires additional analgesia when performed due to the high invasiveness of the method itself. The possibility of damage to the pelvic organs is not excluded. All of these shortcomings increase the execution time of the blockade, not guaranteeing its full effectiveness.

There is a method of blocking the sciatic nerve by lateral access by injecting a needle in the frontal plane to a point located 1-1.5 cm posterior to the posterior edge of the greater trochanter with its passage to a depth of 7-10 cm until it contacts the outer surface of the sciatic tubercle [Pashchuk A. YU. Regional anesthesia. - M .: Medicine, 1987, p.65]. Despite the apparent simplicity, this method is traumatic (contact with the bone) and leads to a high frequency of "mosaic" block, increasing the percentage of failures.

There is a method of blocking the sciatic nerve with lateral access by injecting a needle into a point 3 cm below and 1 cm caudal to the greater trochanter [Pandin P. Sciatic nerve blockade in supine position: a novel approach. Canadian Journal of Anesthesia 2003; V.50. - P.52-56]. However, this method makes it difficult to perform blockade in patients with skeletal traction, since their limb is bent in the knee and hip joints, which leads to a displacement of the anatomical landmarks. This increases the search time for the nerve, reducing the speed of the blockade. A prolonged nerve search makes it impossible to perform the method in the ward without prior sedation.

Closest to the proposed is a method of blocking the sciatic nerve with lateral access, described in patent RU 2342957 C1, which we took as a prototype (Fig. 1).

The method consists in the following: the injured limb located on the splint is bent at the knee and hip joints, a soft roller is placed under the lower back. Then draw a vertical line passing along the upper edge of the greater trochanter, and a horizontal line passing along the rear edge of the greater trochanter, and at the intersection of these lines determine the point of injection (1). The needle is inserted perpendicular to the skin and 10-15 ° caudally. The blockade is performed with a 22G needle, at least 10 cm long, using an electric stimulator to verify the position of the needle. This access allows you to achieve effective blockade by reducing the time of nerve search compared to the above counterparts. However, the main drawback of this technique is the need to determine several landmarks, imposing a forced position on the body, which does not exclude the possibility of contact of the needle with the joint bag, bone structures and large vessels, certainly increasing the invasiveness of manipulation in fractures of bones of the lower extremity. In general, this modification requires a certain qualification of the anesthesiologist, in our opinion, it is quite traumatic and increases the execution time of the block, which is important in urgent surgery.

The technical result of the present invention is to simplify the method and reduce the execution time of the procedure by using one reference point to determine the position of the needle point of needle and its safe conduct.

This result is achieved by the fact that in the known method of blocking the sciatic nerve with lateral access, including determining the point of injection of the needle, according to the invention in the position of the patient on the back, the point of injection of the needle is determined by 2-4 cm from the lower edge of the greater trochanter along a line drawn perpendicular to the axis of the limb down from the most protruding part with the subsequent holding of the needle parallel to the plane of the operating table to verify its position relative to the sciatic nerve, in the absence of verification Nia needle redirect its fan-like in the axial plane by an angle of 10-15 °.

It is advisable to verify the position of the needle using the method of paresthesia or induced muscle contractions by means of an electroneurostimulator, or imaging a nerve by ultrasonography.

It is also advisable to use a needle 10-15 cm long for the procedure.

If prolonged blockade is necessary, it is advisable to pass a catheter through the needle and perform analgesia through it for 2-6 days.

The use of a line drawn downward from the most protruding part of the greater trochanter perpendicular to the axis of the limb to determine the point of injection of the needle allows the use of only one bone landmark, which is easily determined in any patient, even with severe obesity, which greatly simplifies the implementation of the method.

In this case, finding the point of injection of the needle, as we have experimentally found, stepping back 2-4 cm from the lower edge of the greater trochanter and subsequent holding the needle parallel to the plane of the operating table to verify its position relative to the sciatic nerve, excludes the possibility of its contact with the joint bag, bone structures and large vessels. All this reduces both the invasiveness and the time taken to complete the manipulation.

Providing verification of the location of the needle by receiving paresthesia (a sensation of “tingling” in the area of sciatic nerve innervation), induced muscle contractions (using a neurostimulator), or visualization of the nerve using ultrasonography, which allows the needle to be brought to the nerve under visual control, allows you to quickly and accurately perform the procedure without unnecessary trauma to the patient.

The fan-shaped direction of the needle at an angle of 10-15 ° in the absence of paresthesias, verifying the correct position of the needle relative to the sciatic nerve, taking into account the anatomical features of the passage of the nerve in individual patients, allows to identify the perineural space in such patients with maximum accuracy.

Using a needle 10-15 cm long allows blocking the sciatic nerve in patients of any constitution.

If a prolonged blockade is necessary, passing a catheter through a needle provides adequate and long-term analgesia both in the postoperative period and in severe chronic ischemic pain syndrome.

The essence of the method is illustrated by examples:

Example 1. Patient T., 66 years old (weight 122 kg, height 171 cm, blood pressure - 200/110 mm Hg), medical history No. 5640 was received 02.21.2010 at the Salekhard Regional Clinical Hospital in an emergency with a diagnosis : closed comminuted fracture of the calcaneus and 1 and 2 metatarsal bones.

Concomitant diseases: common atherosclerosis, coronary heart disease, stage III hypertension, risk 3, stable angina pectoris of functional class I. Type II diabetes mellitus, subcompensation. Morbid obesity.

Upon admission to the hospital with a special purpose preventive analgesia in connection with severe pain, a sciatic nerve block was performed, which included the following manipulations.

In the patient’s position on the back, the most protruding part of the greater trochanter was palpated (Fig. 2, vol. V), a vertical line (A) was drawn down, perpendicular to the axis of the lower limb, and, retreating 4 cm down this line from the lower edge of the trochanter (t .1), we determined the point of injection (v. 3). Given the pronounced obesity of the patient, a 150 mm long needle was inserted parallel to the table plane to a depth of 14 cm and did not achieve visible results. In this regard, it took a fan-shaped redirection of the needle by ≈15 ° to obtain plantar flexion of the foot in response to irritation of the sciatic nerve. Introduced 20 ml of a 1% solution of ropivacaine.

When performing the blockade, nerve verification was performed using a BBraun Stimuplex electric stimulator, the duration of the exercise was 4-5 minutes. The effectiveness of the method was evaluated after 10 min as follows: the sensor block — pin-prick test (lack of sensory response), the motor block — on the Bromage scale (2 points). Subjective assessment of the patient - the absence of pain at the site of fractures, improved overall health (BP - 150/90 mm Hg). The duration of the block was 7 hours. This made it possible to carry out a full examination, perform immobilization and conduct preoperative preparation without discomfort for the patient.

Example 2. Patient M., 25 years old (weight 70 kg, height 178 cm), medical history No. 6055 was admitted on May 21, 2010 to the Salekhard Regional Clinical Hospital on an emergency basis. It was hit by a car. Diagnosed with concomitant injury, concussion. An open fracture of the bones of the left lower leg and both ankles with extensive soft tissue damage.

As a preoperative preparation in the department, a prolonged sciatic nerve block was made on the left according to the method similar to Example 1 (the injection point was determined 2 cm below the lower edge of the greater trochanter (v.2), nerve verification the first time). Due to the involvement of the lower leg bones in the pathological process, extensive damage to the soft tissues, anesthesia was supplemented with blockade of the femoral nerve from the inguinal access using 20 ml of 1% ropivacaine solution. A catheter was passed through an 18G needle into the perineural space of the sciatic nerve under the control of a neurostimulator to a depth of 3 cm, the needle was removed and the catheter was fixed with a transparent aseptic patch to the skin, through which adequate pain relief was performed daily. The effectiveness of the blockade is confirmed after 8 minutes. Its execution time was 7 minutes.

To ensure blockage of the sciatic nerve, we used the ContraPlex BBraun prolonged blockade kit with a needle length of 100 mm; the volume of the injected anesthetic was 20 ml of a 1% ropivacaine solution simultaneously and 120 ml fractionally (20 ml per day) for 6 days without reducing the effectiveness of analgesia . In the patient's condition, positive dynamics were noted, later surgical treatment was performed.

To date, the proposed method has been treated 51 patients (31 - with fractures of the leg bones, 13 - ankles, 1 - foot bones, 6 - necrectomy of the foot bones) aged 22 to 81 years with simultaneous administration of anesthetic and 4 patients (2 - polytrauma with multiple fractures of the leg and foot bones, 2 - chronic pain syndrome) aged 24 to 76 years - with prolonged blockade of the sciatic nerve up to 2-6 days. In 7 (13.7%) cases, in order to verify the position of the sciatic nerve, due to the excess weight of the patients and, accordingly, the displacement of the anatomical landmarks, a fan-shaped redirection of the needle by an angle of 10-15 ° was required. In 4 (7.8%) cases, “mosaicity” was observed in the anesthesia block diagram supplemented with the administration of opiates (fentanyl) and additional sedation (propofol).

The proposed method in comparison with the known has several significant advantages, the main of which are:

1. Ease of execution by using only one bone landmark to find the point of injection of the needle, while other methods, including the prototype, are associated with the determination of several landmarks, which increases the error in its determination and lengthens the time of manipulation.

2. Minor trauma, due to the choice of the position of the injection point and subsequent holding of the needle on the least mobile, and therefore subject to maceration of the lower limb.

3. If necessary, a prolonged blockade allows the catheter to be fixed without the risk of its migration and outside the limits of the articular bag, bone structures and large vessels, providing a comfortable, adequate analgesia for the patient up to 6 days.

The method is developed at the Department of Anesthesiology and Intensive Care. prof. V.L. Vanevskogo GOU DPO SPbMAPO and underwent clinical testing in 51 patients with a positive result at the Salekhard Regional Clinical Hospital.

Claims (4)

1. A method of blocking the sciatic nerve with lateral access, including determining the point of injection of the needle, characterized in that in the position of the patient on the back, the point of injection of the needle is determined by 2-4 cm from the lower edge of the greater trochanter along a line drawn perpendicular to the axis of the limb down from the most protruding its parts, followed by holding the needle parallel to the plane of the operating table until its position relative to the sciatic nerve is verified, in the absence of verification, the needle is redirected fan-shaped in the axial plane STI an angle 10-15 °. 2. The method according to claim 1, characterized in that the verification of the position of the needle relative to the sciatic nerve is ascertained by obtaining paresthesia, or induced muscle contractions by means of an electroneurostimulator, or by visualizing the nerve by ultrasonography. 3. The method according to PP.1 and 2, characterized in that for the implementation of the blockade using a needle 10-15 cm long. 4. The method according to claim 1, characterized in that, if necessary, a prolonged blockade, a catheter is inserted through the needle, through which analgesia is performed for 2-6 days.

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