Knowing more about your options for pain management can make it easier for you. Whatever you and your medical team decide is best for you, the start of the procedure is the same:. Think of the spinal cord and nerves as wires suspended in a long tube called the dural sac filled with cerebrospinal fluid.
The space around the cord is the epidural space. Back to epidurals and spinals: The main difference is the placement. With an epidural, anesthesia is injected into the epidural space.
With a spinal, the anesthesia is injected into the dural sac that contains cerebrospinal fluid. The direct access means that a spinal gives immediate relief. The following lists give you the other differences. Whereas a spinal gives you pain relief for an hour or two, an epidural offers you the option of pain relief for a longer period of time. Learn more about the pros and cons of epidurals. There are births where a spinal has advantages over an epidural.
If you experience any complications during birth or are having a cesarean delivery, also known as a C-section, your OB may advise you to opt for a spinal. In these cases, you want immediate relief. In addition, by injecting anesthetics directly into the dural sac that contains cerebrospinal fluid, lower doses of medication can be used.
Both epidurals and spinals share the same amount of risk. Your medical team will monitor you closely, as the anesthetics that you receive also affect the central nervous system CNS , cardiovascular system, and respiratory system. This position is often used for caudal approach, especially in children, as this allows for the maintenance of a patent airway because the caudal technique is often performed under general anesthesia in pediatric patients. In this position, the provider often has less dependence on an assistant for positioning.
The provider also has the ability to administer more sedation. The patient should place their feet on a stool and sit up straight, head flexed, arms hugging a pillow, or on a table in front of them. In adults, in the lumbar area, skin to ligamentum flavum depth ranges from 3. The average thickness of the ligamentum flavum is 5 to 6 mm. One must be extra cautious in the dorsal thoracic area to avoid dural puncture and spinal cord injury, as the spinal canal is narrowest here. After a sterile preparation, place a skin wheal at the determined site of insertion using a local anesthetic, followed by anesthetizing the deeper tissues.
Anatomical structures transverse before reaching the epidural space include skin, subcutaneous tissue, supraspinous ligament, and interspinous ligament. Identifying the midline helps immensely to locate the epidural space. The general concept of epidural anesthesia or analgesia is to provide local administration of the anesthetic or analgesic agent into the epidural space. The level of segmental block depends on the distance that the drug diffuses in the rostral or caudal directions as well as volume, concentration, and potency of the drug.
Typically, an gauge needle is used to penetrate through the skin and ligamentum flavum into the epidural space. As the needle is advanced through the ligamentum flavum, resistance to injection of air or saline is continuously or frequently checked. When the tip of the needle is within the ligamentum flavum, air or saline cannot be readily injected. Immediately past the ligamentum flavum, there is a loss of resistance, and air or saline can be injected; this indicates that the needle tip has entered the epidural space.
Loss of resistance technique. Once the needle is placed into the ligamentum flavum, remove the stylet. Attach a glass syringe with 2 to 3 ml of preservative-free normal saline and a small 0. The needle is held steady by the non-dominant hand, and the dominant hand holds the syringe. Steady pressure is applied to the plunger to compress the air bubble. Slowly and steadily advance the needle until loss of resistance is noted and the air bubble and saline get sucked in.
Hanging drop technique. Place the needle into the ligamentum flavum. Next, apply a drop of preservative-free normal saline to the hub of the needle. Apply slow, steady pressure to the needle until the hanging drop gets sucked in as the epidural space contains subatmospheric pressure. In addition to localization of the needle tip within the epidural space, injection of air or saline pushes the dura away from the needle tip, thus, reducing the risk of puncturing or entering the subarachnoid space.
A flexible catheter is then inserted through the needle bore and passed approximately 2 to 3 cm into the epidural space. To prevent migration of the catheter out of the epidural space during labor and delivery in obstetric patients, the catheter can be inserted 4 to 5 cm. The needle is withdrawn, and the catheter immobilized so that multiple injections of medications into the epidural space can be performed Aspiration of the catheter for CSF is attempted to determine if the catheter tip is within the subarachnoid space.
Test doses small volumes of an anesthetic and epinephrine are routinely injected to determine if the catheter tip is in the subarachnoid space leading to unexpected spinal block or intravenous vessel causing tachycardia from the epinephrine.
A test dose consists of 3 ml of 1. Aspiration of the catheter for CSF and the injection of test doses should be performed before each injection of medication to ensure that the catheter tip has not migrated through the dura into the subarachnoid space. Mahajan and coworkers recommend that the catheter should be inserted 1 to 2 hours preoperatively in an awake patient This provides ample time to place the catheter and accurately assess the level of sensory analgesia with local anesthetic drug before surgery begins.
Accurate positioning of the catheter is only confirmed by bilateral sensory block. Anything other than an effective bilateral block suggests that the catheter may not be correctly positioned, with pleural puncture as one of the possibilities Among the various methods epidural anesthesia providers use to identify the epidural space, some use air, some use fluid, and others use a combination of air and fluid during the loss of resistance technique. It has long been speculated that loss of resistance to air results in a lesser quality of analgesia compared with loss of resistance to only fluid.
In a study that also included a systematic review with meta-analysis of 4 older studies, Sanford and colleagues found inconclusive evidence in determining whether a difference in analgesia quality results from the use of air or fluid during the loss of resistance technique Instrumentation for epidural injection has included a novel spring-loaded syringe, which is a potentially useful loss of resistance syringe that provides a reliable, objective endpoint for identification of the epidural space.
It is an optimal pressure, loss of resistance device for identifying the epidural space. In addition to offering good Tuohy needle control, Epidrum also helps in performing epidural anesthesia quickly compared to the loss of resistance or hanging drop technique.
Vital signs, pulse oximetry, level of consciousness, block progression, and signs and symptoms of toxicity should be monitored continuously. Numbness of the arms and hands, problems with breathing, and altered level of consciousness might suggest block progression. Postoperative care should include assessment of block regression, followed by full return of baseline motor and sensory functions.
In the likely event of hypotension, patient should be treated with a Trendelenburg position, additional intravenous fluids, oxygen, and vasopressors as needed. If urinary retention occurs, it should be dealt with appropriately. Lumbar puncture is indicated in the diagnosis of bacterial, fungal, mycobacterial, and viral CNS infections as follows and, in certain settings, for help in the diagnosis of subarachnoid hemorrhage, with a normal CT scan of the brain.
Lumbar puncture is also needed as a therapeutic or diagnostic maneuver in the following situations 35 ; 11 ; 22 :. Lumbar epidural anesthesia or analgesia. Lumbar epidural anesthesia or analgesia is indicated for regional anesthesia of the lumbosacral segments during obstetric, gynecologic, urologic, orthopedic, and general surgical procedures and for postoperative pain control. It is often performed in conjunction with general anesthesia to permit lighter, general anesthesia followed by postoperative analgesia.
Lumbar epidural analgesia has also been used in patients with severe pain in the lumbosacral segments, such as from cancer or reflex sympathetic dystrophy. Based on their study, Choi and colleagues concluded that it is possible to offer regional block to women with inherited bleeding disorders provided their coagulation defects have normalized, either spontaneously during pregnancy or following adequate hemostatic cover Lumbar puncture should not be performed in the following situations:.
In the hands of an inexperienced physician, this might require lumbar puncture under fluoroscopy Ross ; Lumbar puncture and intracranial hypertension. The risk of holding or postponing a spinal tap because of concern of the risk of brain herniation is small. In these patients antibiotics should be started immediately along with a mannitol infusion, with other interventions to control increased intracranial pressure, including attention to airway, breathing, and circulation.
This should be immediately followed by a brain CT and not a spinal tap. Hence, a detailed neurologic examination is essential before deciding on a lumbar puncture. Hence, a normal CT scan in acute bacterial meningitis does not equate to a safe lumbar puncture. With the evidence available, lumbar puncture is temporally strongly associated with brain herniation and is also considered causative in precipitating the same. Current international guidelines recommend cerebral CT before lumbar puncture in many adults with suspected acute bacterial meningitis, due to concern about lumbar puncture-induced cerebral herniation.
Still the guideline emphasis is on early treatment based on symptoms. Glimaker and colleagues argue that performing CT prior to lumbar puncture implies a risk of delayed acute bacterial meningitis treatment, which may be associated with a fatal outcome They further feel that firm evidence for lumbar puncture-induced herniation in adult acute bacterial meningitis is absent and brain CT cannot discard herniation. Lumbar puncture with coagulopathy. Foerster and colleagues in their studies found that even in thrombocytopenic patients, an epidural hematoma would be a relatively rare complication following lumbar puncture Only meager published data are available regarding the provision and safety of neuraxial techniques in patients with common bleeding diatheses.
The minimum "safe" factor levels and platelet count for neuraxial techniques remain undefined in both the obstetric and general populations. Based on the available information, evidence-based recommendations in the setting of hemophilia, von Willebrand disease, or idiopathic thrombocytopenic purpura cannot be offered Lumbar epidural anesthesia and analgesia. In addition to the contraindication mentioned earlier, some other relative contraindications for lumbar epidural anesthesia and analgesia include allergies to an anesthetic or analgesic agent, anticoagulation, systemic or local infection, and lumbar spinal stenosis.
An international normalized ratio greater than 1. Cohn and colleagues analyzed complications of short-term intrathecal macrocatheters in obstetric patients They revealed that intrathecal catheters are dependable and an option for labor analgesia and surgical anesthesia for cesarean delivery with miniscule serious and long-lasting complications.
The goals of lumbar epidural anesthesia are to induce regional anesthesia of the lumbosacral segments and avoid or reduce the depth of general anesthesia. The goals of lumbar epidural analgesia are to provide regional analgesia in postoperative or chronic pain patients and avoid or reduce the need for systemic analgesic control.
Effects of epidural anesthesia on motor function and sympathetic innervation resulting in a reduction in vital capacity and forced expiratory volume in 1 s FEV 1. Still, these effects are so small that the beneficial effects far overweigh the side effects. Postoperatively, early extubation, improvement in pain therapy, and improved diaphragmatic function are noted. Overall, epidural anesthesia not only provides excellent anesthesia and analgesia but also improves postoperative outcome and reduces postoperative pulmonary complications compared with anesthesia and analgesia without epidural anesthesia A variety of anesthetic or analgesic agents can be injected.
Typical anesthetics include lidocaine, bupivacaine, etidocaine, tetracaine, chloroprocaine, prilocaine, procaine, dibucaine, and mepivacaine. Epinephrine is frequently added to induce local vasoconstriction and reduce systemic uptake of the local anesthetic agent. Besides reducing systemic toxicity, epinephrine increases the local potency of the anesthetic drug. Analgesic agents injected include fentanyl, morphine, and droperidol.
Epidural catheterizations provide regional anesthesia and analgesia during childbirth or surgical procedures. Ultrasound imaging can reduce the risk of failed or traumatic lumbar punctures and epidural catheterizations, as well as the number of needle insertions and redirections Ultrasound may be a useful adjunct for these procedures Like in lumbar puncture, the performance of epidural catheterizations and palpation of anatomical landmarks as well as visual imagery of the local anatomy, the angle of needle progression, and assessment of the distance from the skin to the target space, rely on the skill, confidence, and experience of the operator.
Obesity, local edema, or anatomical variations might make the procedure more difficult to perform. Fluoroscopy is often used as a rescue modality after failed lumbar punctures Fluoroscopy is expensive, not readily available or portable, requires multiple operators, and involves radiation exposure Hence, ultrasound is recommended over fluoroscopy.
Jacobson and colleagues have utilized fluoroscopy-guided curved-needle transforaminal approach in patients with spinal muscular atrophy requiring nusinersen intrathecal injections These patients have a challenging spine with complete interlaminar osseous fusion and the modified needle has made the technique fully successful.
Forty-five milligrams of lidocaine, if injected intrathecally, will result in a spinal anesthetic. Epidural anesthesia. Apart from technical complications such as needle contacting spinous process, needle contacting lamina, inability to thread the catheter, continuous return of fluid suggestive of needle traversing the dura into the subarachnoid space, blood return suggesting needle entry in to epidural vein, other complications include pain, paresthesia and pain with injection as well as a failed epidural.
Factors leading to failed epidural include false loss of resistance, misplaced local anesthetic, unilateral block, segmental sparing, and visceral pain. Catheter migration might occur, leading to intravascular or intrathecal injections. It is ideal to consider aspiration before each dose to check the position of the needle and also to increase the dose in small increments.
A retrospective review revealed a relatively high rate of unintended intradiscal injections that occurs in the performance of the retrodiscal approach for transforaminal epidural steroid injections Unfortunately, this carries a likely risk of disc injury induced by the needle puncture.
Rana and colleagues have shown that inserting an intrathecal catheter after a recognized accidental dural puncture significantly reduced the need for an epidural blood patch Lumbar puncture and epidural injections can be carried out in pregnancy when indicated without any added risks as in normal adults. Injection of a local anesthetic into the lumbar epidural space results in diffusion of the drug in the rostral and caudal directions.
Direct contact of the drug with the spinal roots as they cross the epidural space and possibly the dorsal root ganglia causes anesthesia at those levels Thus, the level of anesthesia is defined by the extent of rostral and caudal diffusion of the drug as well as the concentration, volume, and potency of the drug. The therapeutic effect of local anesthetics is to produce anesthesia by temporary blockade of nerve conduction through reversible inhibition of sodium channels. However, animal studies have demonstrated direct neurotoxic effects of anesthetics at high concentrations, such as are sometimes produced during epidural anesthesia 09 ; Breakdown of the blood-brain or blood-nerve barrier, such as with intraneural or subarachnoid injection, leads to neurotoxicity at lower concentrations of local anesthetics Epidural catheters are normally placed between two vertebral disks so that the medications can flow into the extradural space.
The medications administered diffuse naturally from the extradural space and through the dura mater to the cerebral spinal fluid, which is located in the intrathecal space. A lumbar puncture is typically required, and the medications are delivered by intermittent injections or by ambulatory infusion devices.
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