Spinal nerve block

Spinal nerve block Administration of local anesthesia into the spinal canal between the arachnoid membrane and the pia mater (i.e., the subarachnoid space). 

Local anesthetics are used to block pain conduction by nerves. They are used for infiltration anesthesia, local nerve blocks, spinal nerve blocks and epidural nerve blocks. The first local anesthetic was cocaine, which has largely been replaced by synthetic agents. 

Lidocaine hydrochloride [73-78-9] (Xylocaine), is the most versatile local anesthetic agent because of its moderate potency and duration of action, rapid onset, topical activity, and low toxicity. Its main indications are for infiltration, peripheral nerve blocks, extradural anesthesia, and in spinal anesthesia where a duration of 30 to 60 min is desirable. Because of its vasodilator activity, addition of the vasoconstrictor, epinephrine, increases the duration of action of Hdocaine markedly. It is also available in ointment or aerosol preparations for a variety of topical appHcations. 

The primary site of action of epidurally administered agents is on the spinal nerve roots. As with spinal anesthesia, the choice of drug to be used is determined primarily by the duration of anesthesia desired. However, when a catheter has been placed, short-acting drugs can be administered repeatedly. Bupivacaine is typically used when a long duration of surgical block is needed. Lidocaine is used most often for intermediate length procedures chloroprocaine is used when only a very short duration of anesthesia is required. 

Other options for labor analgesia include spinal analgesia and nerve blocks. 

Local anesthetics are used for topical anesthesia, local infiltration, peripheral nerve block, paravertebral anesthesia, intravenous block also known as regional anesthesia, epidural block, and spinal i.e. subarachnoid blockade. The local anesthetics may be divided into two main groups, the esters and the amide-type agents. 

The first clinical uses of a local anesthetic agent occurred in 1884, when cocaine was employed as a topical agent for eye surgery and to produce a nerve block. These events inaugurated a new era, that of regional anesthesia. New applications were developed, including spinal, epidural, and caudal anesthesia. The search for a better local anesthetic led to chemical synthesis of a number of other compounds that have more selective local anesthetic properties and few systemic side effects. 

Procaine hydrochloride Novocain) is readily hydrolyzed by plasma cholinesterase, although hepatic metabolism also occurs. It is not effective topically but is employed for infiltration, nerve block, and spinal anesthesia. It has a relatively slow onset and short (1 hour) duration of action. All concentrations can be combined with epinephrine. It is available in dental cartridges with phenylephrine as the vasoconstrictor. 

Lidocaine hydrochloride Xylocaine) is the most commonly used local anesthetic. It is well tolerated, and in addition to its use in infiltration and regional nerve blocks, it is commonly used for spinal and topical anesthesia and as an antiarrhythmic agent (see Chapter 16). Lidocaine has a more rapidly occurring, more intense, and more prolonged duration of action than does procaine. 

Procaine is ineffective when administered through surface application, and is used only by injection. The onset of action for the drug is 2 to 5 minutes, and its duration of action is short. Vasoconstrictors are usually co-administered with this vasodilator drug to delay its absorption and to increase the duration of action. The drug is used for infiltration anesthesia, peripheral nerve block, and spinal anesthesia. 

Lignocaine injections are indicated for production of local or regional anaesthesia by infiltration techniques such as percutaneous injection, peripheral nerve block, spinal or subarachnoid block. 

It is a potent and long acting local anaesthetic used for spinal, infiltration, epidural anaesthesia and nerve block. 

Adrenaline along with local anaesthetics may be used for infiltration, nerve block and spinal anaesthesia for prolonging the action and to reduce the systemic toxicity of local anaesthetics. 

The choice of local anesthetic for infiltration, peripheral nerve blocks, and central neuraxis (spinal/epidural) blockade is usually based on the duration of action required. Procaine and chloroprocaine are short-acting lidocaine, mepivacaine, and prilocaine have an intermediate duration of action and tetracaine, bupivacaine, levobupivacaine, and ropivacaine are long-... 

Clinical use Mepivacaine has been employed for all types of infiltration and conduction nerve block anesthesia using solutions of 1.0 and 1.5 % lasting for 1.5 to 3 h. Epidural anesthesia with 2.0 % mepivacaine has a rapid onset with a dense motor block. Hyperbaric solutions of mepivacaine have also been used for spinal anesthesia (Tetzlaff, 2000). Mepivacaine has been used for topical applications, but other LA such as lidocaine are more effective. 

Moreover, duration of central NKi receptor blockade is a critical point, as anesthetic-like nerve block caused by non-specific effects on ion channels in peripheral tissues could mask the selective antinociceptive effects of blocking NKi receptors in the spinal cord. The long-acting NKi antagonist L-733,060 maintained blockade of central NKi receptors at a time when peak plasma drug levels had subsided. Therefore, in paw licking experiments, the inhibitory effect of L-733,060 appeared to be due to central NKi receptor blockade (Rupniak et al., 1996). 

Pharmacological Profile. The profile of the ideal local anesthetic agent depends largely on the type and length of the surgical procedure for which it is applied. Procedures could include neuraxial (spinal and epidural) anesthesia, nerve and plexus blocks, or field blocks (local infiltration). In general, tine ideal agent should have a short onset of anesthesia and be useful for multiple indications such as infiltration, nerve blocks. 

Bupivacaine Marcaine, Sensor-caine Slow to Intermediate Long Infiltration Peripheral nerve block Epidural Spinal Sympathetic block... 

Lidocaine Xylocaine Rapid Intermediate Infiltration Peripheral Nerve Block Epidural Spinal Transdermal Topical Sympathetic block Intravenous regional block... 

Generic Name Procaine Trade Name(s) Novocain Onset of Action Intermediate Duration of Action Short Principle Use(s) Infiltration Peripheral nerve block Spinal... 

Central neural blockade. The anesthetic is injected within the spaces surrounding the spinal cord10 (Fig. 12-2). Specifically, the term epidural nerve blockade refers to injection of the drug into the epidural space—that is, the space between the bony vertebral column and the dura mater. A variation of epidural administration known as a caudal block is sometimes performed by injecting the local anesthetic into the lumbar epidural space via the sacral hiatus (see Fig. 12-2). Spinal nerve blockade refers to injection within the subarachnoid space— that is, the space between the arachnoid membrane and the pia mater. Spinal blockade is also referred to as intrathecal anesthesia because the drug is injected within the tissue sheaths surrounding the spinal cord (intrathecal means within a sheath see Chapter 2). 

Casati A, Cappelleri G, Aldegheri G, et al. Total intravenous anesthesia, spinal anesthesia or combined sciatic-femoral nerve block for outpatient knee arthroscopy. Minerva Anestesiol. 2004 70 493-502. 

Pain referred from visceras to skin supplied by same spinal segment Peripheral nerve block (Bupivacaine)... 

Zhuang, Z. Y., Wen, Y. R., Zhang, D. R., Borsello, T., Bonny, C., Strichartz, G. R., Decosterd, I., and Ji, R. R. (2006). A peptide c-Jun N-terminal kinase (JNK) inhibitor blocks mechanical allodynia after spinal nerve ligation Respective roles of JNK activation in primary sensory neurons and spinal astrocytes for neuropathic pain development and maintenance.. Neurosci. 26, 3551 -3560. 

When appropriate, peripheral nerve block with a local anaesthetic, or neural axis block, e.g., spinal or epidural, provides intraoperative analgesia and muscle relaxation. These local anaesthetic techniques provide excellent postoperative analgesia. 

Bupivacaine is long-acting 3 h) (see Table 18.1) and is used for peripheral nerve blocks, and epidural and spinal anaesthesia. Whilst onset of effect is comparable to lidocaine, peak effect occurs later (30 min). 

High spinal anesthesia after inadvertent injection is a possible complication of intercostal nerve block (SED-12, 252). Pneumothorax is another reported complication (55). 

Use For nerve block, infiltration, epidural (also called saddle block) and spinal anesthesias. Also used to treat cardiac dysthymias Half-life 2-10 minutes Onset 1.5-5 minutes Peaks 0.5-2 hours Duration 1 1 hours, depending on location... 

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