Epidural Nerve Block
- By : Dr. Kareem
- Category : General
Epidural nerve block has become a significant advance in neuraxial anesthesia and analgesia. Dr. James Leonard Corning described the procedure in 1885 [1] and Cuban anesthesiologist Manual Martinez Curbelo, in 1947, first used an epidural catheter. [2]
The procedure is commonly performed as a sole anesthetic or in combination with spinal or general anesthetic. The duration of anesthesia or analgesia is prolonged when epidural catheters are used. Patients are able to control their pain with patient-controlled epidural analgesia (PCEA) in a manner similar manner to that of intravenous patient-controlled analgesia (IV PCA).
Local anesthetic epidural blockade may be useful in conjunction with aggressive physical therapy or manipulation of a painful limb associated with joint stiffness or limited range of motion. Lumbar sympathetic blocks are more appropriate for evaluating and treating complex regional pain syndromes, as they provide a more selective evaluation by providing a discrete sympathetic block.
In comparison to epidural blocks, epidural injections of local anesthetic, steroids, or both are considered for the treatment of radicular pain symptoms secondary to disk herniation or postsurgical radicular pain. Epidural injections do not alter the course of the underlying process but may offer effective pain relief in selected patients. Epidural injections may be performed in the spinal region, including the cervical, thoracic, lumbar, and sacral regions. Fluoroscopic guidance may be necessary in patients with congenitally, surgically, or pathologically altered anatomy. The injections should be delivered into the area of the known pathology using midline, paravertebral, or transforaminal approaches. Caudal steroid injections should only be used for patients with leg pain of sacral origin or in whom direct access to the lumbar region is impossible.
When considering epidural nerve block, clinicians should follow a stepwise approach. First, an accurate diagnosis must be made by obtaining a pertinent neurological history and examination and performing the appropriate diagnostic confirmatory tests.
In the ever-expanding field of interventional pain management, epidural injections of pain medications like steroids play an important role in chronic pain management. Long-term indwelling epidural catheters are helpful in managing severe pain in cancer and noncancer chronic pain conditions. Certain conditions with sympathetic mediated or maintained pain are treated with the epidural local anesthetic since it provides sympathetic blockade.
Indications
Indications for epidural nerve block can be divided into the following categories:
- Sole epidural anesthetic
- Orthopedics – Surgeries of lower limbs, including hip, knee, and pelvic areas
- Vascular surgery – Lower limbs, amputations
- Obstetrics – Cesarean delivery
- Gynecology – Surgeries of female pelvic organs
- Urology – Prostate and bladder surgeries
- General surgery – Lower abdominal surgeries, including appendectomy, bowel surgeries, hernia repair
- Epidural anesthetic in combination with spinal anesthetic
- This combination is referred to as combined spinal epidural (CSE).
- All of the indications noted above for sole epidural anesthetic may also be performed with CSE.
- Epidural anesthetic in combination with general anesthetic
- All of the indications noted above for sole epidural anesthetic may also be performed with CSE.
- Pediatric surgery – Penile procedures, inguinal hernia repair, lower limb orthopedic procedures
- Thoracic surgery -Thoracotomy, cardiac bypass, other cardiac surgeries
- Epidural analgesia combined with general anesthesia reduces the incidence of postoperative pneumonia in patients with chronic obstructive pulmonary disease who are undergoing major abdominal surgery. [3]
- Epidural analgesia [4, 5]
- Prolonged postoperative analgesia obtained by continuous or patient-controlled infusions of local anesthetics, opioids, adjuvants, or a combination thereof
- Labor epidural analgesia
- Single-shot epidural injection of depot form of morphine (Duramorph) can provide 6-24 hours of analgesia. DepoDur (EKR Therapeutics, Bedminster, NJ) is a formulation that provides more than 2 days of analgesia with a single injection.
- Epidural for chronic pain management [6, 7, 8, 9]
- Disk herniation, degeneration, and spondylosis
- Radiculopathy -Cervical, thoracic, lumbosacral
- Spinal stenosis and facet arthropathy
- Sympathetic mediated/maintained pain of upper or lower extremities
- Pelvic pain – Aid with pelvic floor physical therapy
Contraindications
Absolute contraindications
See the list below:
- Patient refusal
- Uncorrected hypovolemia
- Increased intracranial pressure
- Infection at the site
- Allergy to local anesthetic (For more information, see Local Anesthetic Agents, Infiltrative Administration.)
Relative contraindications
See the list below:
- Coagulopathy
- Platelet count < 100,000
- Uncooperative patient
- Spine abnormalities and surgeries
- Sepsis
- Unstable spine from trauma
- Positioning problems
- General anesthesia (controversial)
Because of the rare occurrence of spinal hematoma associated with neuraxial anesthesia in patients taking anticoagulants, a consensus statement has been developed by the American Society of Regional Anesthesia and Pain Medicine (ASRA). [10] Recommendations from the consensus statement are depicted in the table below. For more information, see ASRA’s consensus statement on Regional Anesthesia in the Anticoagulated Patient.
Technique
Identification of Epidural Space
Several methods can be used to identify the epidural space. They include the following:
- Loss of resistance to air or preservative-free normal saline
- Compression of a small air bubble in saline (This method is the author’s preference.)
- Hanging drop technique
- Pop-off feeling
- Nerve stimulation
- Ultrasound: Although often perceived as difficult to use in this capacity, ultrasonography is useful for identifying intervertebral levels, estimating the depth to epidural and intrathecal spaces, and locating important landmarks
