Peripheral Nerve Blocks: A Color Atlas, 3rd Edition

49.Lumbar Plexus Blocks

Giorgio Ivani

Valeria Mossetti

A. Posterior Approach

Patient Position: The patient is in the lateral decubitus position, the side to be blocked lying uppermost.

Indications: Anesthesia and postoperative analgesia for hip, femur, or knee surgery.

Needle Size: A 22-gauge, 50-mm, insulated beveled needle; for older children 100 mm.

Volume: Ropivacaine 0.2% for children up to 7 years, levobupivacaine 0.5% for older children, 0.5 mL/kg.

Anatomic Landmarks: The posterior superior iliac spine, the iliac crest, and the spinous process of L4.

Approach and Technique: The site of needle insertion is the intersection between the vertical line drawn from the highest point of the iliac crest and the line drawn from the posterior superior iliac spine parallel to midline along the spinous processes of L4 and L5. The needle connected to the nerve stimulator set at 1.5 mA and 2 Hz is introduced perpendicular to the skin in search of the transverse process of L4. Then redirect the needle cranial or caudal and 1 cm deeper until stimulation of the femoral nerve is elicited (contraction of the quadriceps muscle, usually the vastus lateralis muscle). Adjust the position of the needle to maintain the appropriate muscle response with a current of 0.4 to 0.5 mA. Then, after negative aspiration, slowly inject the local anesthetic solution.

Tips

1.   This block is more difficult and not free of complications in a pediatric patient, therefore should only be performed by anesthesiologists trained in pediatric regional anesthesia.

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2.   It is important to remember the distance between skin and nerve vary according to the age: 2.5 cm at 1 year increasing to 8 cm in adolescents.

3.   There are some contraindications for this block: coagulation disorders, trauma of the lumbar spine, lumbar vertebral deformities, peritoneal or visceral infections.

4.   Complications include:

· Visceral organ puncture, especially of the kidney. Use the shortest needle that can reach the plexus.

· Subarachnoid (high or total spinal anesthesia) or epidural (contralateral anesthesia) spread. Avoid a medial puncture direction, perform a test dose, inject slowly and while injecting watch closely blood pressure and heart rate.

· Vessel puncture (paravertebral veins).

Suggested Readings

Chayen D, Nathan H, Chayen M. The psoas compartment block. Anaesthesiology 1976;45:95.

Dalens B, Tanguy A, Vanneuville G. Lumbar plexus block in children. Comparison of two procedures in 50 patients. Anaesth Analg 1988;67:750.

Johr M. The right thing in the right place: lumbar plexus block in children. Anesthesiology 2005; 102(4):865; author reply 865–866.

Sciard D, Matuszczak M, Gebhard R. Continuous posterior lumbar plexus block for acute postoperative pain control in young children. Anesthesiology 2001;95(6):1521–1523.

B. Femoral Block

Patient Position: The patient lies supine, the thigh slightly abducted, if possible.

Indications: Anesthesia and postoperative analgesia of the thigh, the medial aspect of the leg, and the periosteum of the femur.

Needle Size: A 23-gauge, 35-mm, insulated beveled needle.

Volume: Ropivacaine 0.2% for children up to 7 years, levobupivacaine 0.5% for older children, 0.5 mL/kg.

Anatomic Landmarks: The inguinal ligament and the femoral artery (Fig 49-1).

Approach and Technique: The femoral artery should be palpated and marked. The site of introduction of the needle is vertically, 0.5 to 1 cm both below the inguinal ligament and lateral to the femoral artery. Set the nerve stimulator at a frequency of 2 Hz and a current of 2.5 mA. Connect this to the pen dedicated for the transcutaneous technique (instead of the pen it is possible to use the negative electrode of the ENS) and point it perpendicular to the skin in an anteroposterior direction until a motor response of the femoral nerve is elicited (contraction of the quadriceps muscle with the phenomenon of the “dancing patella”). Then insert the needle connected to the nerve stimulator set at 1 mA and 2 Hz, exactly at the point evidenced via transcutaneous in an anteroposterior direction until the motor response is again elicited. Adjust the position of the needle to maintain the appropriate muscle response with a current of 0.4 to 0.5 mA. Then, after negative aspiration, slowly inject the local anesthetic solution.

Figure 49-1. The inguinal ligament and the femoral artery.

Tips

1.   This block has a very high success rate, around 100%, without any particular contraindications or side effects, except vessel (femoral vein and artery) puncture.

2.   This block will be unsuccessful in cases of sartorius muscle stimulation.

Suggested Readings

Johnson CM. Continuous femoral nerve blockade for analgesia in children with femoral fractures. Anaesth Intensive Care 1994;22(3):281–283.

Koo ST, Brown TCK. Femoral nerve block. The anatomical basis for a single injection technique. Anaesth Intens Care 1983;11:40.

Maccani RM, Wedel DJ, Melton A. Femoral and lateral femoral cutaneous nerve block for muscle biopsies in children. Paediatr Anaesth 1995;5(4):223–227.

Ronchi L, Rosenbaum D, Athouel A, et al. Femoral nerve blockade in children using bupivacaine. Anaesthesiology 1989;70:622.

Tobias JD. Continuous femoral nerve block to provide analgesia following femur fracture in a paediatric ICU population. Anaesth Intens Care 1994;22(5):616–618.

C. Fascia Iliaca Compartment Block

Patient Position: On back, the thigh slightly abducted, if possible.

Indications: Anesthesia and postoperative analgesia of the thigh, the medial aspect of the leg, the periosteum of the femur, and the knee.

Needle Size: A short beveled needle; e.g., a caudal needle.

Volume: Ropivacaine 0.2% for children up to 7 years, levobupivacaine 0.5% for older children, 0.5 mL/kg.

Anatomic Landmarks: Inguinal ligament (Fig 49-2).

Approach and Technique: The line uniting the pubic spine to the anterior superior iliac spine is divided in three equal parts. A short beveled needle is then introduced vertically 0.5 to 1 cm below the union of the lateral one-third to the medial two-thirds; that is, at least 2 to 3 cm lateral to the femoral artery, until two losses of resistance, respectively corresponding to the fascia lata and the fascia iliaca, are felt. No electroneurostimulator can be used in performing this block as no motor fibers are present at this level.

Figure 49-2. Inguinal ligament.

 

Tips

1.   The fascia iliaca compartment block is a multi-block technique with a single injection. The anesthetic solution is injected at the inner face of the fascia iliaca along which it spreads and can contact all the nerves emerging from the psoas compartment.

2.   The femoral nerve (100%) and the lateral femoral cutaneous and the obturator nerves (70% to 90%) are blocked with this technique.

Suggested Readings

Dalens B, Vanneuville G, Tanguy A. Comparison of the fascia iliaca compartment block with the 3-in-1 block in children. Anaesth Analg 1989;69:705.

Paut O, Sallaberry M, Schreiber-Deturmey E, et al. Continuous fascia iliaca compartment block in children: a prospective evaluation of plasma bupivacaine concentrations, pain scores, and side effects. Anesth Analg 2001;92(5):1159–1163.

D. Saphenous Nerve Block

Patient Position: On back, the thigh in neutral position.

Indications: In combination with sciatic nerve block for surgery on the whole leg and foot.

Needle Size: A 23- to 25-gauge, 35-mm, insulated beveled needle.

Volume: 0.1 to 0.2 mL/kg ropivacaine 0.2% for children up to 7 years, levobupivacaine, 0.5% for older children.

Anatomic Landmarks: The saphenous nerve, terminal branch of the femoral nerve, is a pure sensory nerve that runs alongside with the motor nerve supplying the vastus medialis muscle. The femoral artery and the inguinal ligament.

Approach and Technique: The site of introduction of the needle is vertically, 0.5 cm lateral to the femoral artery and 3 to 6 cm (depending on the patient's age and size) below the inguinal ligament. Set the nerve stimulator at a frequency of 2 Hz and a current of 2.5 mA. Connect this to the pen dedicated for the transcutaneous technique (instead of the pen it is possible to use the negative electrode of the ENS) and point it perpendicular to the skin in an anteroposterior direction until a motor response of the vastus medialis is elicited. Then insert the needle connected to the nerve stimulator set at 1 mA and 2 Hz exactly at the point evidenced via transcutaneous in an anteroposterior direction until the motor response is again elicited. Adjust the position of the needle to maintain the appropriate muscle response with a current of 0.4 to 0.5 mA. Then, after negative aspiration, slowly inject the local anesthetic solution.

Suggested Reading

Bouaziz H, Benhamou D, Narchi P. A new approach for saphenous nerve block. Reg Anesth 1996;21:490.