Aspect | Epidural Anesthesia | Spinal Anesthesia |
Needle | Touhy needle | Spinal needle (Quincke, whitacre, sprotte tip) |
Definition | Injection of anesthetic into the epidural space (b/w ligamentum flavum and duramater) of the spinal cord. | Injection of anesthetic into the subarachnoid space (directly into the cerebrospinal fluid). |
Spinal level that can be performed | Anywhere along the verteral column | Lumbar only (mostly below the L2 vertebran; where spinal cord ends) |
Location | Epidural space, outside the dura mater. | Subarachnoid space, inside the dura mater. |
Drug dose | Larger dose than SA | Smaller dose than EA |
Onset of Action | Slower (10-20 minutes). | Rapid (2-5 minutes). |
Duration of block | Adjustable, prolonged | Brief, usually 2-4 hours |
Redosing | Possible via inserted catheter | Not possible |
Hypotension and headache | No; because there is no CSF leak | Yes; due to CSF leak |