What is the most common complication of spinal anesthesia?

October 11, 2025 •

4 min read

With an overall incidence rate that may be as high as 7% for neuraxial blocks, the most common complication of spinal anesthesia is a post-dural puncture headache (PDPH). This occurs due to cerebrospinal fluid (CSF) leakage following the puncture of the dura mater, leading to intracranial hypotension.

Quick Summary

Post-dural puncture headache (PDPH) is the most frequent complication following spinal anesthesia, caused by cerebrospinal fluid leakage and reduced intracranial pressure. Its hallmark is a severe headache that worsens when upright and improves when lying flat. Management includes conservative measures and epidural blood patches, with prevention focused on using smaller, atraumatic needles.

Key Points

PDPH is the most common complication: Post-dural puncture headache (PDPH) is the most frequent adverse event following spinal anesthesia, caused by cerebrospinal fluid leakage.
Postural nature of pain: The key diagnostic feature of PDPH is that the severe headache worsens when upright and improves when lying flat.
Needle choice reduces risk: Using small-gauge, atraumatic, pencil-point needles can significantly lower the incidence of PDPH compared to larger, cutting needles.
Epidural blood patch is definitive treatment: For severe or persistent PDPH that does not respond to conservative care, an epidural blood patch (EBP) is the most effective treatment.
Other common issues are minor: Other frequent complications like hypotension, nausea, and backache are typically mild and manageable with standard medical care.
Rare, severe complications exist: Although extremely rare, more serious complications such as infection, nerve damage, and spinal hematoma are possible and require immediate attention.

Understanding Post-Dural Puncture Headache (PDPH)

Following spinal anesthesia, the most common complication is a post-dural puncture headache (PDPH). This specific type of headache is a direct result of the procedure, where the spinal needle creates a small hole in the dura mater, the tough membrane surrounding the spinal cord. A persistent leak of cerebrospinal fluid (CSF) through this hole reduces the volume and pressure of the fluid protecting the brain and spinal cord. This loss of cushioning allows the brain to sag slightly when the patient is upright, pulling on pain-sensitive structures like the meninges and blood vessels, which causes the severe, characteristic headache.

Typical Symptoms and Onset of PDPH

The defining symptom of PDPH is its postural nature: the headache worsens when sitting or standing and is often relieved by lying flat. The pain is typically described as dull or throbbing and can be bilateral, affecting the front or back of the head, and sometimes radiating to the neck and shoulders. Other associated symptoms may include:

Nausea and vomiting
Neck stiffness
Dizziness or vertigo
Changes in hearing, such as muffled hearing or tinnitus
Sensitivity to light (photophobia)

Symptoms typically begin within 24 to 48 hours after the procedure, though onset can occur up to five days later. While many cases resolve spontaneously within a week or two, severe or persistent PDPH requires active intervention.

Factors Influencing PDPH Risk

Several factors can influence a patient's risk of developing a PDPH:

Needle Size and Type: Larger-gauge, cutting-point needles (like the Quincke) are associated with a higher risk compared to smaller-gauge, atraumatic, pencil-point needles (like the Whitacre or Sprotte). Pencil-point needles spread rather than cut the dural fibers, promoting faster sealing of the puncture site.
Needle Orientation: When using cutting needles, inserting the bevel parallel to the longitudinal dural fibers minimizes the risk of a persistent leak.
Patient Demographics: Young adults (especially those aged 18-30), women, and pregnant individuals are at an increased risk.
Technique: Multiple dural puncture attempts can increase the risk of PDPH.

Other Common Complications of Spinal Anesthesia

While PDPH is the most discussed complication, several other more common but typically minor issues can arise from spinal anesthesia. The table below compares the most frequent complications, including PDPH.


Complication	Cause	Symptoms	Treatment
Post-Dural Puncture Headache (PDPH)	Leakage of CSF from the dural puncture site, causing intracranial hypotension.	Severe, postural headache (worse when upright, better when flat), nausea, neck stiffness.	Conservative management (fluids, caffeine, analgesics), epidural blood patch for persistent cases.
Hypotension	Blockade of sympathetic nerves, leading to widespread vasodilation and a drop in blood pressure.	Lightheadedness, feeling faint, dizziness, nausea.	Intravenous fluids, vasopressor medications.
Nausea and Vomiting	Often a secondary symptom of hypotension, but can also be triggered by changes in blood pressure.	Feeling sick to the stomach, stomach cramps, vomiting.	Treating the underlying hypotension; anti-nausea medication.
Backache	Localized trauma from the needle or stretching of ligaments, which is generally mild and self-limiting.	Pain or soreness at the injection site.	Simple analgesics, warm or cold compresses.
Urinary Retention	Local anesthetic blocking the nerves that control bladder function, temporarily inhibiting the voiding reflex.	Inability to urinate post-procedure.	Catheterization if necessary, resolves as the anesthetic wears off.

Prevention and Treatment of Complications

Prevention of PDPH is primarily focused on the anesthesia technique. Using a small-gauge, atraumatic pencil-point needle is the most effective way to reduce the risk. In the past, bed rest and increased fluid intake were recommended for prevention, but recent evidence does not support these practices.

For treating PDPH, a conservative approach is often tried first and is successful in many cases. Conservative treatments include:

Analgesics, such as NSAIDs or acetaminophen
Increased fluid intake, particularly caffeinated drinks, which can constrict cerebral blood vessels
Resting in a flat position

If conservative measures fail or symptoms are severe, the gold standard treatment is an epidural blood patch (EBP). In this procedure, a small amount of the patient's own blood is injected into the epidural space, forming a clot that seals the dural puncture site.

Rare but Serious Complications

While the above complications are the most common, spinal anesthesia also carries a risk of rare but serious events that anesthesiologists are trained to recognize and manage. These include:

Total spinal anesthesia: The accidental injection of a high dose of anesthetic into the subarachnoid space, leading to widespread paralysis, severe hypotension, and respiratory compromise.
Spinal hematoma: A blood clot that forms in the epidural space, compressing the spinal cord and potentially causing permanent paralysis if not treated promptly.
Infection: Meningitis or an epidural abscess, although very rare with sterile technique, can occur.
Nerve injury: Direct needle trauma to a nerve or spinal cord is extremely rare but can cause permanent damage.

Conclusion

While a variety of complications are possible with spinal anesthesia, the most common is the post-dural puncture headache (PDPH), caused by CSF leakage. Advances in needle technology, such as the use of small-gauge, atraumatic needles, have significantly reduced its incidence. For those who do experience PDPH, effective treatment options are available, from conservative management to the highly successful epidural blood patch procedure. Other frequent complications like hypotension and nausea are typically minor and easily managed. Anesthesiologists are trained to minimize all risks and to identify and address any complications that arise, ensuring patient safety throughout the procedure. For more detailed information on specific complications or patient experiences, it is important to consult with a qualified medical professional.

Visit MedlinePlus for more information on spinal and epidural anesthesia

Frequently Asked Questions

A PDPH typically feels like a severe, throbbing headache that is primarily located at the front or back of the head. Its key characteristic is that the pain is significantly worse when you sit or stand and dramatically improves when you lie down.

A post-dural puncture headache often resolves on its own within one to two weeks, though some cases may last longer if left untreated. With an epidural blood patch, relief is often rapid.

Lying flat can temporarily relieve the symptoms of a PDPH once it has developed. However, medical evidence does not support the practice of routine bed rest or increased fluid intake immediately after the procedure as a preventative measure.

For persistent or severe PDPH, the most effective treatment is an epidural blood patch (EBP). This involves injecting a small amount of the patient's own blood into the epidural space to seal the CSF leak.

The local anesthetic used in spinal anesthesia blocks the sympathetic nerves, which control the tone of blood vessels. This causes vasodilation (widening of blood vessels), leading to a drop in blood pressure (hypotension).

Permanent nerve damage is an extremely rare complication of spinal anesthesia. Temporary symptoms like numbness or weakness can occur but typically resolve within days or weeks.

Total spinal anesthesia is a very rare but dangerous complication that occurs when an unusually high dose of anesthetic spreads too far up the spinal cord. It can cause severe hypotension, respiratory distress, and loss of consciousness.