Introduction:
Our backbone, or the spine, has seven cervicals, twelve thoracics, five lumbar, and five sacral vertebral bones. These vertebrae are joined together with articulating joints and ligaments. The spinal cord is present inside these vertebrae in the canal. The spinal block is performed in the middle or lower lumbar levels to prevent damage to cervical and thoracic levels. The lumbar approach does not block the arms and neck.
What Is a Spinal Block?
Spinal anesthesia or block is the anesthesia given into the subarachnoid space in the spinal cord. Therefore, the anesthesia is also called the subarachnoid block. Spinal block can block the nerve of the arms, legs, neck, and buttocks, but the doctor gives the injection at the lumbar, so the arms and neck are not blocked. Spinal anesthesia is a type of regional anesthesia. It is used alone or in combination with other anesthesia. Spinal and epidural anesthesia can work in some cases, like cesarean section. It is mainly used in the lower abdomen, pelvis, and lower extremities.
What Are the Drugs Used in Spinal Blocks?
Drugs used in the spinal blocks are:
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Lidocaine (5 %) - The onset of action of Lidocaine starts in three to five minutes and lasts for one to 1.5 hours.
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Bupivacaine (0.75 %) - Mostly used drug in spinal blocks. Its onset of action takes 5 to 8 minutes and lasts about 90 to 150 minutes.
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Tetracaine (0.5 %).
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Mepivacaine (2 %).
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Ropivacaine (0.75 %).
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Levobupivacaine (0.5 %).
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Chloroprocaine (3 %).
When to Go For Spinal Blocks?
Spinal anesthesia is required in many surgical cases involving the lower abdomen, pelvis, and perineal and lower extremities. It is beneficial in patients below the umbilicus. Spinal anesthesia is also used in pain management. Unfortunately, few patients also go with combinations of regional or general anesthesia. The indications of the spinal block are:
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Vascular surgery on the legs.
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Cystectomy with general anesthesia.
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Cesarean sections with epidurals.
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Orthopedic surgery involves pelvis, hip, femur, tibia, and knee replacement.
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Pain management in regular deliveries or birth.
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Hysterectomy (surgery to remove the womb).
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Surgeries related to urology.
When to Not Use the Spinal Blocks?
There are many contraindications to the spinal blocks. Some of them are:
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There is increased intracranial pressure (rise of force outside the skull).
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When there is an infection at the site of a surgical procedure.
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When there is any neurological disease present.
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When there is severe dehydration.
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When there is chronic hypertension.
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Conditions like thrombocytopenia (deficiency of platelets in the blood).
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Any heart diseases, congenital or acquired, like mitral and aortic stenosis (valves in the heart getting narrowed).
What Are the Preoperative Measures Taken Before the Spinal Anesthesia Is Given?
Preoperative measures are taken before operating on the patients. A few of them are:
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The patient family history should be noted down.
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Physical examination of the patients is essential.
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Any previous exposure to anesthesia.
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Any allergy patient is suffering.
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Check the site of anesthesia before, and no signs of infections should be present.
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Any spine abnormalities are to be checked.
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Blood pressure, oxygen levels, and temperature are checked.
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The doctor should take consent from the patient beforehand.
What Is the Procedure for the Spinal Block?
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When the patient has gone for preoperative selection by the doctor, the procedure is carried out further by managing the patient's position for needle insertion.
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The patient is made to sit or lay laterally. The patient's positioning is crucial because it creates a straight path for the needle to insert into the spinal sac. The most common position is sitting. While sitting, the patient should flex his spine, so the interspace between the spine open and straight access can be formed.
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After the patient's proper positioning is maintained, the doctor accesses the insertion site. The space present between the two spinous hard bodies in the backbone is the actual site. A clean, aseptic procedure should be performed.
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Along with doctors, the patient should also wear a cap so that no hair can cause infection on an open wound.
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After the positioning, the patient’s area of insertion is checked and cleaned. The skin is cleaned with an antiseptic solution to disinfect the skin. Disinfection of the skin prevents the patient from infection.
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Local anesthesia (one percent Lidocaine) is used for skin infiltration.
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After the local infiltration, the needle is inserted into the skin. The needle passes the outer skin to fat under the skin to the spine's ligaments.
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When the resistance fails to encounter, and a "pop" sound comes, the doctor realizes it is an epidural space. Epidural space in which epidural anesthesia is performed. Epidural spaces are just outside the spinal sac.
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More passage for spinal anesthesia is made; the needle should reach the subarachnoid area. It is the right site for the administration of spinal anesthesia.
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In some cases, the use of the catheter with a needle depends on the surgical requirements. If a catheter is required, it is taped, and the needle is removed from the site for more administration of anesthesia.
What Are the Complications Related to the Spinal Blocks?
Complications of the spinal block are:
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Problems related to backache are widespread after the use of anesthesia on the backbone.
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Postdural puncture headaches are the second most common complication patients have.
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Hypotension can lead to shivering and chills after the surgery.
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Nausea and vomiting.
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Hearing loss.
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Spinal hematoma.
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Arachnoiditis is the infection of subarachnoid spaces.
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Neurological injury.
Is Spinal Block Beneficial?
Yes, the spinal block is beneficial as advancements in this field have made the patient conscious during surgery. And the facility of postoperative pain management has benefited the patients to recover smoothly. In comparison with general anesthesia, it makes the patient unconscious and complicates the surgical situation, whereas the spinal block (regional anesthesia) remains the patient awake during surgery. One benefit example is the Cesarean section connects the mother to infants in the surgical theaters.
Conclusion:
Spinal blocks are given at the spine's lower or mid-lumber areas to protect the cervical and thoracic levels. Spinal blocks are presented in subarachnoid spaces, also called subarachnoid blocks. They are combined with other anesthesia, or the spinal block is used in lower abdomen surgeries. They are administered by needles carrying Lidocaine and Bupivacaine. Block administration requires an entirely aseptic environment to overcome infection.