What is Spinal Anesthesia?
Spinal anesthesia is a form of regional anesthesia that involves the injection of certain anesthetic drugs into a fluid-filled space in which the spinal cord and the nerves arising from it are suspended using a fine long needle. The drug then mixes with the fluid, and acts on the nerve fibers, blocking their activity for a finite time. This renders the portion of the body below the level of the injection numb and anesthetized while the rest of the body remains active.
This fluid-filled space is called the subarachnoid space and the injection is given in the region of the lumbar (low back) spine. This form of anesthesia is easy to administer and is ideally suited for surgeries performed in the lower parts of the body.
- Surgeries below the level of the umbilicus; examples are genitourinary surgery, gynecological surgery, hernia repairs, and surgeries performed on the lower extremities.
- It is especially suited for older patients and those with diseases such as chronic respiratory/renal/
- Diabetics also face an advantage from spinal anesthesia.
- It is also suitable in cases of trauma where there is a need for emergency surgery.
The patient is usually positioned in a sitting posture on the operating table. A small stool for placing the foot can be given for the patient’s convenience and support. The forearms can be made to rest on the thighs to make the patient stable and comfortable.
Alternatively, the procedure can be performed with the patient lying on their side with their hips and knees maximally flexed in the form of the letter C.
Following positioning, the anesthetist will clean the back using an antiseptic solution. He may administer a little bit of local anesthetic to numb the skin at the point where he is going to give the spinal so that you do not feel the pain due to the spinal needle.
The anesthetic solution is then injected into the spinal space usually between the lumbar vertebrae L3 and L4 through a long thin needle, (a little wider than a human hair) after ascertaining its correct position from the flow of the cerebrospinal fluid.
The position and point of injection are subject to change and can vary from one individual to another. After successful administration, you will be positioned in the required position and once again all your parameters will be checked by the anesthetist.
- Relatively cheap
- Patient satisfaction
- Reduced risk of respiratory complications
- Superior muscle relaxation
- Less bleeding
- Quick restoration of
- Reduced incidence of coagulation disorders following surgery
- Reduced post operative stay
The time required for the performance of the procedure varies depending on the anesthetist's skill and competence.
In some cases, it might be difficult to locate the dural space and obtain cerebrospinal fluid. The procedure has to be avoided in such situations.
It is generally not advisable to employ spinal anesthesia for surgeries lasting for more than 2 hours.
Spinal anesthesia may not be suited for a certain group of patients even if they are sedated. This is because different people react or respond in different ways to anesthesia.
- Spinal anesthesia should not be attempted when there is a lack of availability of proper equipment for resuscitation and also general anesthesia, in case the spinal fails. Special consideration should be given to patients with abnormal bleeding and clotting parameters, or liver disease. Furthermore, patients receiving anticoagulants such as warfarin or heparin are at increased risk of developing complications.
- Patients with severe fluid loss either by bleeding, vomiting, or diarrhea should be replaced with adequate fluids before being taken up for spinal anesthesia due to the risk of hypotension.
- Patient's refusal for the administration either due to lack of knowledge or preference for general anesthesia. It might be possible to convince some patients if the situation is properly explained.
- Uncooperative patients such as children, mentally challenged individuals, or patients with psychiatric disorders.
- Anatomical difficulties that might make the administration of anesthesia difficult.
- Presence of neurological disease, or infection of skin around the lumbar area in the back.
- Spinal and epidural anesthesia: MedlinePlus - (https://medlineplus.gov/ency/article/007413.htm)
Latest Publications and Research on Spinal Anesthesia
- A randomized double-blind comparison of the double-space technique versus the single-space technique in combined spinal-epidural anesthesia for cesarean section. - Published by PubMed
- Use of nitroglycerin for parallel transverse uterine cesarean section in patients with pernicious placenta previa and placenta accrete and predicted difficult airway: A case report and review of literature. - Published by PubMed
- Assessment of an ultrasound-guided technique for catheterization of the caudal thoracic paravertebral space in dog cadavers. - Published by PubMed
- Spinal anesthesia is a viable option for emergent laparoscopic procedure in high-risk patients. - Published by PubMed
- Ultrasound-guided erector spinae plane block in canine cadavers: relevant anatomy and injectate distribution. - Published by PubMed