In performing a surgery there are several means of anaesthetising a patient or the area in which the surgery is performed. In instances where the surgery is performed below the level of the umbilicus, a specialized technique called ‘spinal anesthesia’ can be performed.
What is the basis for using spinal anesthesia?
The technique makes use of the facts that nerve supply below the umbilicus is from the nerves which arises from the spinal cord below a certain level and that the cerebro spinal fluid or the CSF fluid covers the spinal cord through out the vertebral column. Thus, an anesthetic agent injected into the CSF fluid can neutralize the action potentials generated in these nerve roots and thereby prevent the patient from feeling. Certain characteristics of the anesthetic agent will prevent it from flowing or climbing up the spinal cord and affect the higher order nerves which facilitate respiration.
How is the procedure done?
The procedure is performed at the time of the surgery on the surgical table. The patient is asked to sit with an arched back holding onto a pillow tucked between the arms and the chest. The anesthetist will explain the procedure and will inject a local anesthetic agent in to the skin and the tissues up to the vertebral column near the lower back. Then the anesthetist will insert a spinal needle through the skin in to the dural space of the spinal cord where the CSF is present and will inject a small quantity of anesthetic agent into the space. Following that a tight plaster will be placed on the site and the patient will be laid on the theater table.
Once the spinal is given, the patient will not feel below his or her waist and this would facilitate performing surgeries pertaining to that area.
Usually, the spinal anesthesia is given for surgeries which take less than 2 hours.
What are the advantages of using spinal anesthesia?
There are some distinct advantages in using spinal anesthesia than using general anesthesia. These are,
Much less respiratory complications Less bleeding Return of gut functions rather quickly Less possibility of Deep Vein Thrombosis Less likelihood of going into hypoglycemia in diabetic patients More patient satisfaction Can be used in patient who are unsuitable for general anesthesia
What are the disadvantages in using spinal anesthesia?
Similarly, there can be certain disadvantages as well.
It might not suite for all patients It is difficult to perform in certain instances Might result in hypotension and respiratory distress with a higher block Possibility of infection in extremely rare instances
What are the contraindications for giving spinal anesthesia?
There are few contraindications to the use of spinal anesthesia. These are,
Sepsis Increased intra cranial pressures Hypovolaemia Clotting disorders leading to bleeding Deformities of the spinal cord