Epidural anesthesia represents a neuraxial technique involving local anesthetic injection into the spinal epidural space to anesthetize nerve roots. This method is commonly employed for abdominal, pelvic, and lower extremity surgeries, sometimes combined with general anesthesia for thoracic procedures, and provides effective postoperative pain management.
The procedure requires needle insertion between vertebrae with anesthetic injection into the epidural space — the region between the dural sac and spinal canal interior, extending from the foramen magnum to sacral hiatus. Administration occurs via needle alone or catheter, typically at lumbar or thoracic levels, occasionally cervical, determined by surgical requirements.
A caudal approach for epidural placement is primarily used in pediatrics for surgeries up to the umbilicus and in adults for chronic low back pain management. Historical obstetric use declined due to efficacy concerns and maternal complications, leading to the widespread adoption of lumbar epidural techniques.
In pediatric practice, single injection epidural anesthesia with a caudal approach is frequently used for postoperative analgesia in infants and toddlers, providing four to six hours of pain relief for abdominal procedures. Adjunctive medications like preservative-free clonidine can extend duration and depth, though infants face increased local anesthetic systemic toxicity risk.
The technique employs three approaches: a blind technique using sacral hiatus identification at a 45-degree angle insertion; ultrasound-guided visualization; or fluoroscopic guidance for improved accuracy and safety in complex cases.
While caudal blocks have a high success rate and are relatively safe, they can be associated with complications. Total spinal anesthesia from inadvertent dural puncture represents a significant risk, particularly in infants whose dural sac terminates at S3–4 versus the adult S1–2 level. Additional complications include subdural, intravascular, or intraosseous injections, infections, hypotension, nerve injuries, hematoma, anesthetic toxicity, delayed respiratory depression, urinary retention, and sacral osteomyelitis.