A. Intrathecal Block
B. Subarachnoid Block
C. Spinal Anesthesia
D. Epidural Anesthesia
Ans:D. Epidural Anesthesia
Anatomy of Epidural Space:
- The cephalad part of the spinal epidural space begins at the level of the foramen magnum.
- The caudal part extends to the sacrococcygeal membrane.
- The anterior portion of the epidural space is formed by the posterior longitudinal ligament, which covers the posterior part of the vertebral body and the intravertebral disk.
- Posteriorly, the epidural space is formed by the anterior lateral surface of the vertebral lamina and the ligament flavum.
- Laterally, the epidural space is formed by the pedicles of the vertebrae and the intravertebral foramen.
- The sitting position is commonly employed. Instruct the patient rest his or her legs on a step stool and hold a pillow. Instruct the patient to arch forward like an angry cat to decrease lumbar lordosis.
- The lateral decubitus position is another possible position.
- Insertion Techniques
- Interlaminar technique
- Transforaminal technique
Epidural versus Spinal Anesthesia
- In epidural anesthesia, the anesthetic drug is injected in epidural space & in spinal anesthesia, the drug is injected in subarachnoid space.
- In comparison to spinal anesthesia, the volume of drug given is larger, onset on effect is delayed (5-20 min) and duration of action is prolonged in epidural anesthesia.
- Both epidural & spinal anesthesia block sympathetic outflow (T12 – L2). This produces dilation of resistance and capacitance vessels decreasing venous return & causing hypotension. However, this fall is sudden & profound in spinal anesthesia, whereas slower & profound in epidural anesthesia.
- Centrineuraxial (spinal & epidural) anesthesia is contraindicated in coagulopathy, blood dyscrasias, full anticoagulant (oral warfarin, LMVV heparin & fibrinolytic) therapy but can be given to patients on antiplatelet agents like aspirin & NSAIDs.