Side effects of spinal anaesthesia: definition, frequency and what you need to know
Side effects of spinal anaesthesia are adverse reactions following the injection of a local anaesthetic, such as a drop in blood pressure, nausea or urinary retention.
Side effects of spinal anaesthesia
Side effects of spinal anaesthesia are adverse physical reactions following the injection of a local anaesthetic into the subarachnoid space. Common effects: a drop in blood pressure (10–30 %), nausea (10–20 %), urinary retention (10–15 %) and post-spinal headache (1–5 %). Serious complications such as nerve damage are very rare (less than 1 in 10,000).
Table of Contents
Important note
This article is for information purposes only and is not a substitute for a medical diagnosis or advice. If you are unsure, or if you require a personalised treatment plan, it is essential that you consult a qualified specialist.
Side effects of spinal anaesthesia affect anyone undergoing a procedure under this form of spinal anaesthesia. Most reactions are temporary and easily managed. If you are aware of them, you will be able to assess with confidence after the operation what to expect and when medical assistance is required.
Spinal anaesthesia side effects explained: Background & details
Key points at a glance
- Low blood pressure (hypotension) — the most common side effect, occurring in approximately 10–30 % of patients
- Post-dural headache (PDPH) — in approximately 1–5 % of patients, typically depending on position
- Nausea and vomiting — A consequence of a drop in blood pressure; temporary
- Urinary retention — in approximately 10–15 % of patients, catheterisation is occasionally necessary
- Back pain — last for a short time at the injection site, subside of their own accord
- Serious complications (nerve damage, haematoma, infection) — rare to very rare (< 1 : 10.000)
Spinal anaesthesia, also known as lumbar anaesthesia, is a form of regional anaesthesia administered close to the spinal cord. A local anaesthetic — often bupivacaine — is injected into the subarachnoid space using a thin spinal needle. This is the space around the spinal cord that is filled with cerebrospinal fluid. Once there, the drug blocks the transmission of pain signals in the nerves of the lower half of the body. The effect sets in quickly and lasts for 60 to 180 minutes, depending on the dose.
Because spinal anaesthesia acts on an anatomically sensitive area, it can affect the surrounding nervous system and circulation. This is true even when the puncture technique is correct. The risk profile has been well researched and is, on the whole, manageable. According to a study in Regional Anaesthesia and Pain Medicine According to a published review, the incidence of serious neurological complications is less than 1 in 10,000.
How do the side effects of spinal anaesthesia occur?
The side effects of spinal anaesthesia arise through three different mechanisms. Understanding these makes it easier to interpret the reactions following the procedure.
- Sympathetic block and a drop in blood pressure: The local anaesthetic blocks not only pain nerve fibres but also sympathetic nerve fibres. The sympathetic nervous system — part of the autonomic nervous system — regulates vascular tone. When its activity ceases, the blood vessels dilate. Blood pressure falls (hypotension). The heart rate may also decrease (bradycardia). The anaesthesia team therefore monitors blood pressure and heart rate continuously. In the event of a marked drop, they intervene by administering fluids or vasopressors.
- Dural perforation and cerebrospinal fluid leakage: The spinal needle pierces the tough membrane surrounding the brain (dura mater). Cerebrospinal fluid can leak through the resulting hole. The drop in pressure pulls sensitive structures inside the skull slightly downwards. This causes the typical position-dependent post-spinal headache (PDPH, post-dural puncture headache). Thinner pencil-point needles significantly reduce this risk.
- Direct and indirect effects on the nervous system: Local anaesthesia also temporarily blocks the nerve fibres that control bladder function. This results in post-spinal urinary retention. Permanent nerve damage, on the other hand, is very rare. In adults, the spinal cord ends anatomically above the puncture site (between the third and fourth lumbar vertebrae). Direct injury to the spinal cord caused by the needle is therefore virtually impossible.
Spinal anaesthesia versus epidural anaesthesia: differences in the side-effect profile
Spinal anaesthesia and epidural anaesthesia are often confused by patients. Both are procedures carried out close to the spinal cord — but they differ significantly in terms of technique and side-effect profile.
In the Spinal anaesthesia the local anaesthetic enters the subarachnoid space (cerebrospinal fluid space) directly. The effect sets in quickly — often within 5 minutes — and is deeper and more complete. There is a risk of post-dural puncture headache (PDPH) because the dura mater is punctured.
In the Epidural anaesthesia The anaesthetic is injected into the epidural space outside the dura mater. The dura mater itself remains intact. As a result, post-dural puncture headache (PDPH) occurs less frequently. However, the procedure takes longer to take effect and the anaesthetic can be administered continuously via a catheter — as is typically the case with anaesthesia during childbirth.
Spinal anaesthesia is not a substitute for epidural anaesthesia, and vice versa. The anaesthetist decides which procedure to use based on the nature of the operation, the patient’s medical history and their coagulation status.
Side effects with specific frequency data
The following table summarises the main side effects of spinal anaesthesia, together with their incidence rates. The figures are based on data from the medical journal Anaesthesia as well as the PMC review article on spinal anaesthesia (NCBI).
| Side effect | Frequency | History |
|---|---|---|
| Low blood pressure (hypotension) | 10–30 % | Temporary, easily treatable |
| Nausea / Vomiting | 10–20 % | In short, the consequences of hypotension |
| Urinary retention | 10–15 % | Hours to 1 day, with a catheter if necessary |
| Post-dural headache (PDPH) | 1–5 % | 2–7 days; blood patch may be required |
| Back pain at the injection site | 2–5 % | Just a few days to go |
| Allergic reaction | < 1 % | Immediate treatment required |
| Nerve damage (transient) | < 0,1 % | Declining within a matter of weeks |
| Epidural haematoma / abscess | < 1 : 10.000 | Emergency intervention required |
Post-dural headache (PDPH) are particularly distressing from the patient’s perspective. They only set in after the procedure. They subside when lying down, but become more severe when standing. The initial measures are bed rest, plenty of fluids and painkillers. If post-operative postural dizziness lasts longer than 48 hours or is severe, a Blood patch is used. This involves injecting a small amount of the patient’s own blood epidurally. The blood clots and seals the dural leak. The success rate of this method is over 90 %.
| Side effect | Frequency (approx.) | Classification | Fades out to |
|---|---|---|---|
| Low blood pressure (hypotension) | 15–33 % | Very common | Minutes to hours |
| Nausea and vomiting | 10–20 % | Frequently | Hours |
| Urinary retention | 10–15 % | Frequently | Hours (catheter) |
| Post-dural headache (PDPH) | 1–5 % | From time to time | 2–7 days |
| Transient back pain | 1–3 % | From time to time | Days to weeks |
| Nerve damage (transient) | approx. 0.1 % | Rare | Weeks to months |
| Epidural haematoma / abscess | < 0,01 % | Very rare | Individually adjustable |
Myth
Spinal anaesthesia can lead to permanent paralysis.
Fact
Permanent paralysis occurs in fewer than 1 in 10,000 cases. In adults, the spinal cord ends just above L2. Provided the puncture technique is correct, there is therefore no direct risk of injury. Temporary sensory disturbances subside within a few hours.
PMC/NCBI, Esslingen Hospital
Myth
Headaches following spinal anaesthesia are inevitable and can last for weeks.
Fact
Post-spinal headaches (PDPH) occur in 1–5 % of patients. They are caused by a slight loss of cerebrospinal fluid and subside within 2 to 7 days . If symptoms persist, a blood patch is highly effective.
Esslingen Hospital, praktischArzt.de
Myth
Spinal anaesthesia is more dangerous than general anaesthesia.
Fact
Spinal anaesthesia is suitable for certain procedures safer than a general anaesthetic. It prevents respiratory depression and post-operative confusion. It also places less strain on the heart and circulatory system and enables a quicker recovery.
acteurdemasante.lu, PMC/NCBI
Myth
After a spinal anaesthetic, you have to lie in bed for hours to avoid getting a headache.
Fact
According to current guidelines, strict bed rest prevents PDPH not reliable. Adequate fluid intake is more effective. Mobilisation begins once the motor block has subsided.
PMC/NCBI, as at July 2026
When to see a doctor: warning signs and follow-up care
In most patients, symptoms following a spinal anaesthetic subside within a matter of hours to a few days. Some symptoms require immediate medical attention.
Warning signs: Seek immediate medical attention if:
– Persistent or increasing weakness in the legs or bladder after the anaesthetic has completely worn off – Fever, redness or severe pain at the injection site (indicating an infection) – Severe headaches that do not subside when lying down (atypical PDPH) – Numbness or tingling that spreads rather than subsides – Urinary retention lasting longer than 8 hours after the procedure
A common misconception: patients interpret temporary back pain as a sign of injury. This leads to unnecessary panic. Conversely, some people wait too long when symptoms that are actually cause for concern do arise.
The rule of thumb is: if symptoms subside within 24 hours, this is to be expected. If they worsen or new symptoms appear, further investigation is needed.
Experience shows that patients tend to underestimate urinary retention because it does not present with any pain. A full bladder despite the urge to urinate is the typical sign. A short-term single-use catheter reliably resolves the problem.
Spinal anaesthesia for cosmetic procedures: financial risks
Spinal anaesthesia is used in numerous cosmetic and plastic surgery procedures in the lower abdomen and leg areas — including liposuction and tummy tucks. For these procedures, spinal anaesthesia offers clear advantages over general anaesthesia: less post-operative nausea, less strain on the airways and a quicker recovery.
At the same time, cosmetic procedures are subject to a specific financial dynamic. If complications arise — whether due to the anaesthesia or the surgical procedure itself — statutory and private health insurers often do not cover the resulting costs, or only cover them in part. Wound debridement, treatment of infections, a hospital stay following a complication: these costs can quickly add up to several thousand euros.
One Consequential Costs Insurance covers precisely this risk. 4beauty offers this kind of cover for a wide range of cosmetic procedures — with cover of up to 300,000 euros in the event of claims by the health insurance fund and up to 10,000 euros for cosmetic clinics. You can find an overview of the procedures covered by the insurance at Treatments & Procedures.
Frequently Asked Questions about the Side Effects of Spinal Anaesthesia
A drop in blood pressure (hypotension) occurs in approximately 10–30 % of patients. Nausea occurs in approximately 10–20 %. Urinary retention affects approximately 10–15 %. Post-spinal headaches (PDPH) occur in approximately 1–5 % of patients. These reactions are temporary and easily managed. The anaesthesia team monitors blood pressure and heart rate during the procedure and intervenes immediately if necessary.
A drop in blood pressure is treated during the operation. Nausea improves once the anaesthesia wears off. Urinary retention typically lasts up to one day. Post-dural puncture headache (PDPH) may last for 2–7 days. A blood patch relieves the symptoms within hours in severe cases. Back pain at the puncture site disappears after a few days.
Permanent nerve damage caused by spinal anaesthesia is very rare. In adults, the spinal cord anatomically ends above the usual puncture site (between the third and fourth lumbar vertebrae). Direct injury to the spinal cord caused by the needle is therefore practically impossible. The incidence of nerve compression caused by epidural haematomas or abscesses is less than 1 in 10,000. If treated promptly, these conditions have no lasting effects.
The blood patch is the standard treatment for severe post-dural puncture headache (PDPH). It involves injecting a small amount of the patient’s own blood epidurally. The blood clots and seals the hole in the dura mater caused by the spinal needle. The loss of cerebrospinal fluid stops. The success rate of the blood patch is over 90 %. Headaches often improve within minutes to hours.
The medical side-effect profile of spinal anaesthesia does not vary according to the type of procedure. The financial aspect is what matters: in the case of cosmetic surgery such as liposuction or a tummy tuck, health insurance funds often do not cover the follow-up costs arising from complications. Insurance covering follow-up costs protects against this risk. This means you do not have to bear the cost of treatment resulting from anaesthesia-related or surgical complications yourself.
Sources & Further Links
- Wikipedia, Spinal anaesthesia (featured article)
- PMC / PubMed Central, Spinal Anaesthesia (Springer-Verlag, Open Access)
- Esslingen Hospital, Patient Information on Spinal Anaesthesia