Spinal anaesthesia
Encyclopedia
Spinal anaesthesia also called spinal analgesia or sub-arachnoid block (SAB), is a form of regional anaesthesia
involving injection of a local anaesthetic into the subarachnoid space
, generally through a fine needle
, usually 9 cm long (3.5 inches). For extremely obese patients, some anaesthesiologists prefer spinal needles which are 12.7 cm long (5 inches). The tip of the spinal needle has a point or small bevel. Recently, pencil point needles have been made available (Whitacre, Sprotte, Gertie Marx & others).
placed into the epidural space
. This technique has some similarity to spinal anaesthesia, and the two techniques may be easily confused with each other. Differences include:
(Marcaine) is the local anaesthetic most commonly used, although lignocaine (lidocaine
), tetracaine
, procaine
, ropivacaine
, levobupivicaine and cinchocaine
may also be used. Sometimes a vasoconstrictor such as epinephrine
is added to the local anaesthetic to prolong its duration. Of late, many anaesthesiologists are preferring to add opioids like morphine
, fentanyl, or buprenorphine
, or non-opioids like clonidine
, to the local anaesthetic used in a spinal injection, to give a smoother effect and to provide prolonged pain relief once the action of the spinal local anaesthetic has worn off.
Baricity
refers to the density of a substance compared to the density of human cerebral spinal fluid. Baricity is used in anaesthesia to determine the manner in which a particular drug will spread in the intrathecal
space. Usually, the hyperbaric, (for example, hyperbaric bupivacaine) is chosen, as its spread can be effectively and predictably controlled by the anaesthesiologist, by tilting the patient. Hyperbaric solutions are made more dense by adding dextrose to the mixture.
. Thin unmylenated C-fibres associated with pain are blocked first, while thick, heavily mylenated A-alpha motor neurons are blocked last. The desired result is total numbness of the area. A pressure sensation is permissible and often occurs due to incomplete blockade of the thicker A-beta mechanoreceptors. This allows surgical procedures to be performed with no painful sensation to the person undergoing the procedure.
Some sedation
is sometimes provided to help the patient relax and pass the time during the procedure, but with a successful spinal anaesthetic the surgery
can be performed with the patient wide awake.
. To administer a spinal anaesthetic to higher levels may affect the ability to breathe by paralysing the intercostal respiratory muscles, or even the diaphragm
in extreme cases (called a "high spinal", or a "total spinal", with which consciousness is lost), as well as the body's ability to control the heart rate
via the cardiac accelerator fibres. Also, injection of spinal anaesthesia higher than the level of L1 can cause damage to the spinal cord, and is therefore usually not done.
on the spinal nerves of a dog when he accidentally pierced the dura mater
.
The first planned spinal anaesthesia for surgery in man was administered by August Bier
(1861–1949) on 16 August 1898, in Kiel
, when he injected 3 ml of 0.5% cocaine solution into a 34-year-old labourer. After using it on 6 patients, he and his assistant each injected cocaine into the other's spine
. They recommended it for surgeries of legs, but gave it up due to the toxicity of cocaine.
However spinal analgesia is the mainstay of anaesthesia in countries like India
, Pakistan
and parts of Africa
, excluding the major centres. Thousands of spinal anaesthetics are administered daily in hospitals and nursing homes. At a low cost, a surgery of up to two hours duration can be performed below the umbilicus
of the patient
.
Regional anaesthesia
Regional anaesthesia is anaesthesia affecting only a large part of the body, such as a limb or the lower half of the body. Regional anaesthetic techniques can be divided into central and peripheral techniques. The central techniques include so called neuraxial blocks...
involving injection of a local anaesthetic into the subarachnoid space
Subarachnoid space
In the central nervous system, the subarachnoid cavity is the interval between the arachnoid membrane and pia mater....
, generally through a fine needle
Hypodermic needle
A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...
, usually 9 cm long (3.5 inches). For extremely obese patients, some anaesthesiologists prefer spinal needles which are 12.7 cm long (5 inches). The tip of the spinal needle has a point or small bevel. Recently, pencil point needles have been made available (Whitacre, Sprotte, Gertie Marx & others).
Difference from epidural anaesthesia
Epidural anaesthesia is a technique whereby a local anaesthetic drug is injected through a catheterCatheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
placed into the epidural space
Epidural space
In the spine, the epidural space is the outermost part of the spinal canal. It is the space within the canal lying outside the dura mater...
. This technique has some similarity to spinal anaesthesia, and the two techniques may be easily confused with each other. Differences include:
- The involved space is larger for an epidural, and subsequently the injected dose is larger, being about 10–20 mL in epidural anaesthesia compared to 1.5–3.5 mL in a spinal.
- In an epidural, an indwelling catheter may be placed that avails for additional injections later, while a spinal is almost always a one-shot only.
- The onset of analgesia is approximately 15–30 minutes in an epidural, while it is approximately 5 minutes in a spinal.
- An epidural often does not cause as significant neuromuscular block unless specific local anaesthetics are used which block motor fibres as readily as sensory nerve fibres, while a spinal more often does.
- An epidural may be given at a cervical, thoracic, or lumbar site, while a spinal must be injected below L2 to avoid piercing the spinal cord.
Injected substances
BupivacaineBupivacaine
Bupivacaine is a local anaesthetic drug belonging to the amino amide group. AstraZeneca commonly markets it under various trade names, including Marcain, Marcaine, Sensorcaine and Vivacaine.-Indications:...
(Marcaine) is the local anaesthetic most commonly used, although lignocaine (lidocaine
Lidocaine
Lidocaine , Xylocaine, or lignocaine is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.- History :Lidocaine, the first amino...
), tetracaine
Tetracaine
Tetracaine is a potent local anesthetic of the ester group...
, procaine
Procaine
Procaine is a local anesthetic drug of the amino ester group. It is used primarily to reduce the pain of intramuscular injection of penicillin, and it was also used in dentistry. Owing to the ubiquity of the trade name Novocain, in some regions procaine is referred to generically as novocaine...
, ropivacaine
Ropivacaine
Ropivacaine is a local anaesthetic drug belonging to the amino amide group. The name ropivacaine refers to both the racemate and the marketed S-enantiomer...
, levobupivicaine and cinchocaine
Cinchocaine
Cinchocaine is an amide local anesthetic. It is the active ingredient in some topical hemorrhoid creams such as Proctosedyl...
may also be used. Sometimes a vasoconstrictor such as epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
is added to the local anaesthetic to prolong its duration. Of late, many anaesthesiologists are preferring to add opioids like morphine
Morphine
Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
, fentanyl, or buprenorphine
Buprenorphine
Buprenorphine is a semi-synthetic opioid that is used...
, or non-opioids like clonidine
Clonidine
Clonidine is a sympatholytic medication used to treat medical conditions, such as high blood pressure, some pain conditions, ADHD and anxiety/panic disorder...
, to the local anaesthetic used in a spinal injection, to give a smoother effect and to provide prolonged pain relief once the action of the spinal local anaesthetic has worn off.
Baricity
Baricity
Baricity refers to the density of a substance compared to the density of human cerebral spinal fluid. Baricity is used in anesthesia to determine the manner in which a particular drug will spread in the intrathecal space....
refers to the density of a substance compared to the density of human cerebral spinal fluid. Baricity is used in anaesthesia to determine the manner in which a particular drug will spread in the intrathecal
Intrathecal
Intrathecal is an adjective that refers to something introduced into or occurring in the space under the arachnoid membrane of the brain or spinal cord...
space. Usually, the hyperbaric, (for example, hyperbaric bupivacaine) is chosen, as its spread can be effectively and predictably controlled by the anaesthesiologist, by tilting the patient. Hyperbaric solutions are made more dense by adding dextrose to the mixture.
Mechanism
Regardless of the anaesthetic agent (drug) used, the desired effect is to block the transmission of afferent nerve signals from peripheral nociceptors. Sensory signals from the site are blocked, thereby eliminating pain. The degree of neuronal blockade depends on the amount and concentration of local anaesthetic used and the properties of the axonAxon
An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma....
. Thin unmylenated C-fibres associated with pain are blocked first, while thick, heavily mylenated A-alpha motor neurons are blocked last. The desired result is total numbness of the area. A pressure sensation is permissible and often occurs due to incomplete blockade of the thicker A-beta mechanoreceptors. This allows surgical procedures to be performed with no painful sensation to the person undergoing the procedure.
Some sedation
Sedation
Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure...
is sometimes provided to help the patient relax and pass the time during the procedure, but with a successful spinal anaesthetic the surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
can be performed with the patient wide awake.
Limitations
Spinal anaesthetics are typically limited to procedures involving most structures below the upper abdomenAbdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. To administer a spinal anaesthetic to higher levels may affect the ability to breathe by paralysing the intercostal respiratory muscles, or even the diaphragm
Thoracic diaphragm
In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...
in extreme cases (called a "high spinal", or a "total spinal", with which consciousness is lost), as well as the body's ability to control the heart rate
Heart rate
Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....
via the cardiac accelerator fibres. Also, injection of spinal anaesthesia higher than the level of L1 can cause damage to the spinal cord, and is therefore usually not done.
History
The first spinal analgesia was administered in 1885 by Leonard Corning (1855–1923), a neurologist in New York. He was experimenting with cocaineCocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
on the spinal nerves of a dog when he accidentally pierced the dura mater
Dura mater
The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...
.
The first planned spinal anaesthesia for surgery in man was administered by August Bier
August Bier
August Karl Gustav Bier was a German surgeon and a pioneer of spinal anaesthesia. After professorships in Greifswald and Bonn, Bier became a professor at the Charité in Berlin.-Spinal anesthesia:...
(1861–1949) on 16 August 1898, in Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...
, when he injected 3 ml of 0.5% cocaine solution into a 34-year-old labourer. After using it on 6 patients, he and his assistant each injected cocaine into the other's spine
Spinal canal
The spinal canal is the space in vertebrae through which the spinal cord passes. It is a process of the dorsal human body cavity. This canal is enclosed within the vertebral foramen of the vertebrae...
. They recommended it for surgeries of legs, but gave it up due to the toxicity of cocaine.
Worldwide usage
Current usage of this technique is waning in the developed world, with epidural analgesia or combined spinal-epidural anaesthesia emerging as the techniques of choice where the cost of the disposable 'kit' is not an issue.However spinal analgesia is the mainstay of anaesthesia in countries like India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
and parts of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, excluding the major centres. Thousands of spinal anaesthetics are administered daily in hospitals and nursing homes. At a low cost, a surgery of up to two hours duration can be performed below the umbilicus
Umbilicus
Umbilicus may refer to:*Umbilicus , a feature of gastropod, Nautilus and Ammonite shell anatomy*Umbilicus, a synonym for the navel or belly button*Umbilicus , a genus of over ninety species of perennial flowering plants, including:...
of the patient
Patient
A patient is any recipient of healthcare services. The patient is most often ill or injured and in need of treatment by a physician, advanced practice registered nurse, veterinarian, or other health care provider....
.
Indications
This technique is very useful in patients having an irritable airway (bronchial asthma or allergic bronchitis), anatomical abnormalities which make endotracheal intubation very difficult (micrognathia), borderline hypertensives where administration of general anaesthesia or endotracheal intubation can further elevate the blood pressure, procedures in geriatric patients.Contraindications
Non-availability of patient's consent, local infection or sepsis at the site of lumbar puncture, bleeding disorders, space occupying lesions of the brain, disorders of the spine and maternal hypotension.Operations
All surgical interventions below the umbilicus, is the general guiding principle:- Abdominal & vaginal hysterectomies
- Laparoscopy Assisted Vaginal Hysterectomies (LAVH) combined with general anaesthesia
- Caesarean sections
- Hernia (inguinal or epigastric)
- Piles fistulae & fissures
- orthopaedic surgeries on the pelvisPelvisIn human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
, femurFemurThe femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, tibiaTibiaThe tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
and the ankleAnkleThe ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot... - nephrectomyNephrectomyNephrectomy is the surgical removal of a kidney.-History:The first successful nephrectomy was performed by the German surgeon Gustav Simon on August 2, 1869 in Heidelberg. Simon practiced the operation beforehand in animal experiments...
- cholecystectomies
- trauma surgery on the lower limbs, especially if the patient is full-stomach
- Open tubectomies
- Transurethral resection of the prostateTransurethral resection of the prostateTransurethral resection of the prostate is a urological operation. It is used to treat benign prostatic hyperplasia . As the name indicates, it is performed by visualising the prostate through the urethra and removing tissue by electrocautery or sharp dissection...
Complications
Can be broadly classified as immediate (on the operating table) or late (in the ward or in the P.A.C.U. post-anaesthesia care unit):- Spinal shockSpinal shockSpinal shock was first defined by Whytt in 1750 as a loss of sensation accompanied by motor paralysis with initial loss but gradual recovery of reflexes, following a spinal cord injury – most often a complete transection. Reflexes in the spinal cord caudal to the SCI are depressed or absent ,...
. - Cauda equinaCauda equinaThe cauda equina is a structure within the lower end of the spinal column of most vertebrates, that consists of nerve roots and rootlets from above...
injury. - Cardiac arrestCardiac arrestCardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
. - HypothermiaHypothermiaHypothermia is a condition in which core temperature drops below the required temperature for normal metabolism and body functions which is defined as . Body temperature is usually maintained near a constant level of through biologic homeostasis or thermoregulation...
. - Broken needle.
- Bleeding resulting in haematoma, with or without subsequent neurological sequelae due to compression of the spinal nerves
- Infection: immediate within six hours of the spinal anaesthetic manifesting as meningism or meningitis or late, at the site of injection, in the form of pus discharge, due to improper sterilization of the LP set.
- PDPH:post dural puncture head achePost dural puncture headachePost-dural-puncture headache is a complication of puncture of the dura mater...
or post spinal head ache
See also
- EpiduralEpiduralThe term epidural is often short for epidural analgesia, a form of regional analgesia involving injection of drugs through a catheter placed into the epidural space...
- Lumbar punctureLumbar punctureA lumbar puncture is a diagnostic and at times therapeutic procedure that is performed in order to collect a sample of cerebrospinal fluid for biochemical, microbiological, and cytological analysis, or very rarely as a treatment to relieve increased intracranial pressure.-Indications:The...
- Combined spinal and epidural anaesthesiaCombined spinal and epidural anaesthesiaCombined spinal and epidural anaesthesia is a regional anaesthetic technique, which combines the benefits of both spinal anaesthesia and epidural anaesthesia and analgesia. The spinal component gives a rapid onset of a predictable block...
- Transparent reality simulation of spinal anaesthesia
- Various diagrams of needles for Lumbar puncture, Epidural, Spinal Anesthesia, etc