Regional Anesthesia

Regional anesthesia involves numbing a specific area of the body, without affecting either the brain or breathing. In a hip replacement the area covered will be the hip joint, buttock and front and back of the thigh.

Because you will remain conscious, a sedative, such as benzodiazepines, or a low concentration of a general will be given. Either will relax you and put into a light sleep.

Types of regional anesthesia blocks
The most commonly used regional blocks are a) an epidural block (single shot or continuous injection) or b) spinal block (single shot of continuous injection). Other blocks do exist e.g. continuous lumbar plexus blockade and continuous peripheral blockade but are currently still under development and won’t be discussed here at this time.

Spinal Block
Also referred to as spinal anesthesia, spinal analgesia or sub-arachnoid block (SAB)
A spinal block involves injecting the anesthetic into the fluid surrounding the spinal cord in the lower part of the back (the subarachnoid space). This produces a rapid numbing effect that can last for hours, depending on the drug used.

Bupivacaine is the local anesthetic most commonly used. Sometimes a vasoconstrictor such as epinephrine is added to the local anesthetic to prolong its duration. Recently, many anesthesiologists are choosing to add opioids such as morphine, or non-opioids like clonidine, to the local anesthetic. These provide prolonged pain relief (analgesia) once the action of the spinal block has worn off.

Epidural Block
An epidural block uses a small tube (catheter) inserted in your lower back to deliver the anesthetic over a longer time period. The most frequently used one is bupivacaine.

Both types of block are administered in a very similar location; however, the epidural catheter is placed slightly closer to the skin and farther from the spinal cord. The block can be provided in small doses to achieve an anesthetic effect over a long period. Indeed the epidural catheter can be left in place and anesthesia continued after the surgery has finished to help control pain. Normally the patient is given control of the dose received, within preset limits.

Advantages of a regional block
The use of epidural or spinal anesthesia during hip surgery has been linked to: -

• reduced risk of perioperative complications like deep venous thrombosis (DVT)
• less deterioration of cerebral and pulmonary functions in patients who are at high risk for complications, and
• overall reduced blood loss.
• effective and safe postoperative pain control(allowing for lower opioid consumption and improved and earlier rehabilitation).
• High patient satisfaction.

• headaches
• trouble urinating – a catheter may be used to manage urinary incontinence
• allergic reactions – which are rare. These may occur as the anesthetic is given before the start of surgery. The allergic reaction produced consists of itching, swelling, elevated temperature, respiratory distress, increased heart beat, anxiety and in the worst case death. However every operating theater is fully equipped to deal with allergic reactions and will have an anaphylactic kit present.

As the patient is in less pain they are also more able to participate in physical therapy which, in turn, increases their rate of recovery.

The combination of regional and light general is also significantly cheaper than using a general anesthetic alone.
What next?
Learn more about: -
General anesthetics