Comparing Spinal vs. Epidural Anesthesia

Neuraxial anesthesia refers to the administration of local anesthesia around the central nervous system, specifically the spinal cord. Types of neuraxial anesthesia include spinal, epidural, and combined spinal-epidural techniques. The primary difference among these different anesthetic techniques is the anatomic location of injection. Epidural anesthesia is performed by introducing a needle between the lumbar, thoracic, or cervical vertebrae and injecting anesthetic medication into the epidural space, while spinal anesthesia involves administration of medications into the subarachnoid space. However, spinal and epidural anesthesia are applicable to many of the same surgical procedures.

Typically, neuraxial anesthesia is utilized for surgeries involving the lower abdomen and lower extremities. Spinal anesthesia is generally administered as a single injection, while epidural anesthesia is commonly delivered via a catheter for continuous infusion. The insertion of the spinal anesthesia needle is typically targeted at a mid- to low-lumbar intervertebral space, below the termination of the conus medullaris. In contrast, needle placement for an epidural injection can be performed at various locations along the distal end of the neuraxial canal. Catheter-based neuraxial anesthesia allows for prolonged anesthesia and the ability to adjust the onset of the anesthetic. Conversely, single-shot spinal or epidural anesthesia is limited to the duration of action of the administered drug.

Spinal and epidural techniques each have their own set of advantages and disadvantages. Common advantages of spinal anesthesia include: 1) rapid onset of block, 2) a technically easy procedure, 3) low required doses of local anesthetic and opioids, and 4) a reliably symmetric block. Disadvantages of spinal anesthesia include: 1) limited duration of action with single-shot injections, 2) limited ability to extend block, and 3) the requirement of dural puncture.

Advantages of epidural anesthesia include: 1) ability to easily prolong the duration and extent of the block, and 2) may be used for postoperative analgesia. Disadvantages of epidural anesthesia include: 1) relatively slow onset of anesthesia, 2) higher required doses of local anesthetic and opioids than spinal techniques, 3) risk of post-dural puncture headache with unintentional dural puncture, 4) possibility of patchy or asymmetric block, and 5) an unreliable sacral block.

A recent meta-analysis by Cochrane examined the efficacy and side-effects of spinal versus epidural anesthesia in women undergoing caesarean section. The analysis included ten randomized controlled trials. It found no significant differences between spinal and epidural techniques in terms of failure rate, need for additional intraoperative analgesia, conversion to general anesthesia, maternal satisfaction, need for postoperative pain relief, or neonatal intervention. However, although women who received spinal anesthesia had a shorter time from the start of the anesthetic to the start of the operation, they also had a higher likelihood of requiring treatment for hypotension. The authors concluded that both spinal and epidural techniques are effective for providing anesthesia during caesarean section. Still, due to the low incidence and/or lack of reporting, no definitive conclusions could be drawn regarding intraoperative side effects and postoperative complications.

Spinal and epidural anesthesia are two types of neuraxial anesthesia that primarily differ in terms of the anatomic location of local anesthetic administration. While each technique has its own advantages and disadvantages, they are both effective and relatively safe.


Practice Advisory for the Prevention, Diagnosis, and Management of Infectious Complications Associated with Neuraxial Techniques: An Updated Report by the American Society of Anesthesiologists Task Force on Infectious Complications Associated with Neuraxial Techniques and the American Society of Regional Anesthesia and Pain Medicine. Anesthesiology. 2017 Apr;126(4):585-601. doi: 10.1097/ALN.0000000000001521. PMID: 28114178.

Hebl JR, Horlocker TT, Kopp SL, Schroeder DR. Neuraxial blockade in patients with preexisting spinal stenosis, lumbar disk disease, or prior spine surgery: efficacy and neurologic complications. Anesth Analg. 2010 Dec;111(6):1511-9. doi: 10.1213/ANE.0b013e3181f71234. Epub 2010 Sep 22. PMID: 20861423.

Hebl JR, Horlocker TT, Schroeder DR. Neuraxial anesthesia and analgesia in patients with preexisting central nervous system disorders. Anesth Analg. 2006 Jul;103(1):223-8, table of contents. doi: 10.1213/01.ane.0000220896.56427.53. PMID: 16790657.

Hartmann B, Junger A, Klasen J, Benson M, Jost A, Banzhaf A, Hempelmann G. The incidence and risk factors for hypotension after spinal anesthesia induction: an analysis with automated data collection. Anesth Analg. 2002 Jun;94(6):1521-9, table of contents. doi: 10.1097/00000539-200206000-00027. PMID: 12032019.

Carpenter RL, Caplan RA, Brown DL, Stephenson C, Wu R. Incidence and risk factors for side effects of spinal anesthesia. Anesthesiology. 1992 Jun;76(6):906-16. doi: 10.1097/00000542-199206000-00006. PMID: 1599111.

Bonica JJ, Kennedy WF Jr, Ward RJ, Tolas AG. A comparison of the effects of high subarachnoid and epidural anesthesia. Acta Anaesthesiol Scand Suppl. 1966;23:429-37. doi: 10.1111/j.1399-6576.1966.tb01043.x. PMID: 6003651.

Ng K, Parsons J, Cyna AM, Middleton P. Spinal versus epidural anaesthesia for caesarean section. Cochrane Database Syst Rev. 2004;2004(2):CD003765. doi: 10.1002/14651858.CD003765.pub2. PMID: 15106218; PMCID: PMC8728877.