Epidural Injections – Side Effects and Risks

An epidural is a type of injection used in pain management clinics to provide pain relief for a range of conditions – they are also used during childbirth, some types of surgery and for pain relief after some types of surgery.

The spinal cord is safely enveloped in a special covering known as the dura mater inside the spinal canal, epidural describes the space around the dura mater. An epidural injection typically contains local anaesthetic which may be mixed with other substances, depending on the purpose of the epidural.  The procedure involves the insertion of a needle into the epidural space with the aim of providing pain relief, or anaesthesia which induces a loss of sensation.

The components of anaesthetic work by blocking the transmission of nerve signals which relay sensations of pain from the body to the brain, however once the effects of the anaesthetic wear off, normal sensations will return.

Epidural Steroid Injections for Pain Management

epiduralEpidurals are well known for their use in surgical procedures and during childbirth, however they are also used in pain management clinics to help relieve painful symptoms caused by a range of different conditions related to back pain.

Epidural steroid injections and other types of spinal injections are typically composed of a combination of local anaesthetic and steroid. Epidural steroid injections are usually used in the treatment of conditions which produce sciatic like symptoms or radicular pain – where the pain originates in the spine but radiates to other areas of the body, this may occur in the case of an irritated or compressed nerve.

Epidural steroid injections can be administered anywhere along the length of the spine and are often more effective than other types of oral medication, as they directly target the source of the pain, providing an anti-inflammatory solution. Prior to the procedure, the skin at the site of the injection is anaesthetised using a small needle – once the area is sufficiently numb, a larger needle containing a mixture of steroid and local anaesthetic is guided using X-ray and contrast dye into the epidural space.

Other Types of Spinal Injections

Other types of spinal injections may be used in two ways; either to diagnose a source of pain, or to relieve the painful symptoms of a particular condition such as disc problems, spinal stenosis, degenerated facet joints etc.

Nerve Root Block/Dorsal Root Ganglion Block/ Transforaminal Epidural

Sensations are transmitted to and from the spinal cord through a network of nerves to the rest of the body – the dorsal root ganglion refers to a small bulge located on individual nerves at the point in which they join the spinal cord, it is responsible for transmitting sensations to the spinal cord. An injection of local anaesthetic around the dorsal root ganglion can help to block or slow down nerve impulses, helping to both determine and relieve a source of pain if any particular nerve is thought to be the cause of painful symptoms. This type of injection is guided by X-ray and the use of contrast dye.

Facet Joint Injection

Pain originating in the facet joints along the spinal column may also benefit from spinal injection therapy in some cases. In this procedure the injection is administered directly to the joint to relieve pain, X-ray guidance is also used to ensure the needle reaches the right place.

Sacro-iliac Joint Injections

Sacro-iliac joint pain may also be treated with anaesthetic and steroid injections following a similar procedure to facet joint injections.

Possible Risks and Side Effects of Epidural & Spinal Injections for Pain Management

As with any type of procedure, there are a number of possible side effects and potential risks involved with the use of epidural or spinal injections for the purposes of pain management.

Pain at the site of the injection

Many individuals experience some pain at the site of the injection for several days following an epidural as in order to introduce the injection, the needle has to pass through ligaments and between bones. This should resolve itself within a few days following the procedure.

Headache

On some rare occasions during an epidural, the needle penetrates too far and penetrates the dura causing a small amount of CSF to leak out – this is described as a dura puncture and can lead to a severe headache which may require further treatment.

Nausea/Vomiting

An epidural or spinal may provoke sensations of nausea or vomiting, in severe cases this can be treated with anti-sickness medication.

Low Blood Pressure

In some cases, blood pressure may temporarily fall during an epidural, which can lead to sensations of dizziness or faintness.

Numbness Weakness

In some rare cases, the local anaesthetic may spread causing some sensations of numbness and weakness in either an arm or leg, depending on the location of the injection.

Ineffective Pain Relief

Epidural injection treatments for pain relief are not always effective and may not help relieve painful symptoms.

Rare Side Effects

Infection

Infection at the site of the injection is very rare but should be treated immediately to avoid further complications. Any redness, excessive heat or swelling at the site of the injection should be investigated immediately.

Direct Nerve Damage

Both temporary and permanent nerve damage is extremely rare during epidural injection – however when damage does occur it may be a result of direct injury to the sensitive nerves from the needle or the catheter itself, or it may occur as a result of infection or serious bleeding near the spinal cord.

Allergic Reaction

Allergic reactions to anaesthetic or to contrast dye (sometimes used to guide the needle).

Epidural and Spinal Anaesthesia for Surgery

A type of regional anaesthetic, epidural and spinal anaesthetics are used for surgery involving the lower body; this type of anaesthesia allows the individual to remain conscious, but free from pain, as opposed to general anaesthesia where the individual is put into a controlled state of unconsciousness, in which they feel and remember nothing of the surgery. An epidural may also be used to supplement a general anaesthetic during surgery and may be continued after the surgery to assist in pain control.

Both epidural and spinal anaesthesia involve an injection of anaesthetic medication into the epidural space, and both procedures are typically performed with the patient either sitting or lying down on an operating table, however each type of injection works in a different way.  During an epidural, the anaesthetist uses a larger needle to introduce an epidural catheter (a thin type of catheter) into the epidural space, providing a supply of local anaesthetic and sometimes other types of pain relief medication, through an epidural pump. This supplies medication continuously through the catheter for pain control during childbirth or surgery, or for pain relief following some types of surgery.

Spinal injections are used for surgical purposes such as obstetrics, (caesarean sections), urology (bladder operations), orthopaedics and vascular surgery. Following successful administration of a spinal block, the individual will remain conscious but not be able to move their legs or feel anything below the waist for the duration of the procedure.

Possible Risks and Side Effects of Epidural & Spinal Injections for Surgery

All surgical procedures carry with them potential risks and possible side effects – such risks may be more likely to apply to some than others. Prior to any type of surgical procedure, the potential benefits and risks will be carefully considered to determine if surgery is indeed the most suitable option.

Potential Side Effects of Regional Anaesthetics:

  • Pain at the site of the injection (see above).
  • Headache (see above).
  • Low blood pressure (see above).
  • Nausea/vomiting (see above).
  • Numbness/weakness (see above).
  • Shivering – Shivering following an epidural or a spinal block associated with surgery, is relatively common and is usually a result of a drop in the body’s core temperature, due to exposure to the cool environment of the operating theatre – during spinal anaesthetics blood vessels are opened up to the skin, this increases blood flow and heat loss.
  • Itching – this may be a side effect of the pain relief drugs used in the epidural.
  • Inability to urinate – a catheter into the bladder may be required after some types of surgery if the anaesthetic has affected the nerves around the bladder.
  • Inadequate pain relief – complete pain relief may not be achieved.

Rare Side Effects

  • Temporary and permanent nerve damage
  • Catheter Infection
  • Convulsions
  • Serious allergy (anaphylaxis)

For more information on epidural and other spinal injections, get in touch today with the Pain Management Clinic.

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