Combination Spinal-Epidural Anesthetic (CSE)

Indications

• Lower extremity surgery

Set-Up

• Epidural anesthesia kit
• 17 gaugeTuohy needle
• For operative orthopedics 2% lidocaine,1.5% mepivacaine 0.5% bupivacaine or 0.75% bupivacaine.

Essential Anatomy

• A line connecting the upper border of the iliac crests crosses the spinous processes of L4 or the L3-4 interspace. The L2-3, L3-4, or L4-5 interspace is commonly used for epidural anesthesia for lower extremity anesthesia.

Technique

• Place the patient either in the sitting or lateral positions with an assistant to hold the patient.
• Consider lightly sedating the patient.
• Aseptically prepare and drape a large area of skin.
• Infiltrate local anesthetic at the epidural puncture site with a long 25 gauge needle.
• Choose the approach:
  • Using the midline approach, place the epidural needle through the skin wheal into the interspinous ligament. The needle should be in the same plane as the spinous processes with a slight cephalad angulation toward the interlaminar space.
  • Using the paramedian approach, place the epidural needle 1.5 cm lateral and slightly caudad to the center of the selected interspace. Aim the needle medially and slightly cephalad so as to pass lateral to the supraspinous ligament. If the lamina is contacted, redirect the needle and “walk off” the lamina in a medial and cephalad direction. Some practioners aim initially for the lamina, with the intent of “walking off” it.
• Advance the epidural needle through the supraspinous and interspinous ligaments in a slightly cephalad direction until the needle lies witin the ligament flavum. Remove the stylet and attach the needle hub a plastic loss-of-resistance syringe containing either air or 3 cc of saline with a small air bubble.
• Constant pressure is applied to the plunger of the syringe as the needle is advanced slowly.• An alternative method is the intermittent technique in which a change of resistance is tested repeatedly between small, careful advances of the epidural needle. When the bevel enters the epidural space, there is a significant loss of resistance to the plunger displacement. When a straight Epidural technique is used:
• Administer a test dose of 3 cc of a local anesthetic with 1:200,000 epinephrine and observe the patient and the patient’s vital signs for signs and symptoms of intrathecal or intravascular injection. The local anesthetic should be administered in 5 ml increments until the appropriate total dose is given.
• Alternatively, you can dose the local through the catheter. This technique may be associated with patchy blocks and a delayed onset of anesthesia. Aspirate before each injection to ensure correct needle placement. When a Combined Spinal Epidural technique is used:
• Advance the spinal needle through the epidural needle until the characteristic “pop” is felt. Make sure that cerebrospinal fluid is flowing through the spinal needle (it may take few seconds with a 27 G needle). Inject the desired volume of local anesthetic and withdraw the spinal needle.
• Thread a 20 gauge radioopaque catheter with 1 cm graduations through the epidural needle.
• Advance the catheter 4-5 cm beyond the needle tip into the epidural space.
• Withdraw the needle over the catheter and secure the catheter onto the patient’s back.

Limitations

• Patients with coagulation abnormalities
• Previous spine surgery at the injection site

Complications

• Intravascular or Intramedullar injection
• Hypotension
• Post-dural puncture headache
• High block resulting in respiratory compromise

Pearls

• If you are accustomed to the midline approach, be careful that with the paramedian approach, the epidural needle may traverse only a small length of ligament before it reaches the epidural space.
• Whether the approach is midline or paramedian, the needle should enter the epidural space in the midline where the space is widest. This results in diminished risk of puncture of epidural veins, spinal arteries and spinal nerve roots, all of which are found primarily in the lateral portion of the epidural space.

These technique descriptions are presented for educational purposes and are not intended to substitute for actual hands-on training.