This article has been professionally reviewed by Tran Thi Anh Hien, MD, Specialist Level I – Department of Anesthesia and Surgery, Vinmec Central Park International General Hospital, and Specialist Level I Nguyen Đuc Thong – Anesthesiologist, Department of General Surgery, Vinmec Da Nang International General Hospital.
In recent years, spinal anesthesia has become one of the most widely used techniques in medical practice. However, its administration may lead to certain complications and side effects during surgery and the postoperative period.
1. What is Spinal Anesthesia?
Spinal anesthesia, also known as subarachnoid anesthesia, is a form of regional anesthesia. The anesthesiologist administers the anesthetic drug into the space between the pia mater and the arachnoid membrane of the spinal cord. This blocks nerve transmission from the spinal cord, resulting in temporary numbness and pain relief in a specific area of the body.
2. Complications and Side Effects of Spinal Anesthesia in Surgery
While spinal anesthesia offers several advantages—such as reduced intraoperative blood loss, a lower risk of venous thromboembolism, and a decreased likelihood of respiratory failure in emergency situations—it is generally considered a safe technique when administered at the appropriate dosage.
However, certain complications and undesirable side effects may still occur, most of which are related either to the anesthetic agent itself or to technical aspects of the procedure, including:
Central Nervous System Complications
The risk of neurological complications following spinal anesthesia increases in patients with pre-existing medical conditions or spinal disorders.
- Neurological Symptoms: Some patients may experience symptoms such as pain, burning sensations in the buttocks, or indigestion after spinal anesthesia. These symptoms typically resolve within two days, and the risk is lower with certain types of local anesthetics.
Cardiovascular Complications
Several cardiovascular complications may arise after spinal anesthesia, including:
- Hypotension: This is a common and often unavoidable complication. Persistent hypotension that fails to resolve can pose serious risks to the patient.
- Cardiac Arrhythmias and Cardiac Arrest: Spinal anesthesia can induce bradycardia, which, if not promptly recognized and treated, may progress to life-threatening cardiac arrest.
Total Spinal Anesthesia
This is a rare but life-threatening complication caused by improper injection placement. Total spinal anesthesia leads to a sudden drop in blood pressure, rapid-onset paralysis, temporary respiratory arrest, loss of consciousness, pupil dilation, and respiratory failure due to extensive nerve blockade.
Upper Airway Obstruction
Common symptoms include nasal congestion, respiratory difficulty, hypoventilation, and respiratory arrest.
Post-Spinal Headache
This is the most common neurological complication following spinal anesthesia, frequently affecting middle-aged women and postpartum patients. The headache typically localizes to the forehead, the area behind the eyes, or the base of the skull (pre-occipital region) and worsens when the patient stands up. Pain severity varies, presenting as either sharp, intermittent episodes or a dull, persistent ache.
Post-spinal headache may be accompanied by nausea and vomiting, lasting from one to four days postoperatively. The primary cause is cerebrospinal fluid (CSF) leakage through the dural puncture site, resulting in reduced cushioning of sensory nerves and decreased intracranial pressure. In addition to headaches, CSF leakage may increase the risk of hearing impairment.
Urinary Retention
This postoperative complication of spinal anesthesia can cause significant discomfort and, in severe cases, may lead to neurogenic bladder dysfunction.
Hematologic Complications
One of the most severe complications of spinal anesthesia is spinal hematoma, which necessitates early surgical intervention to prevent permanent neurological impairment.
Infection
Meningitis, though rare, is a serious complication of spinal anesthesia that may result in permanent neurological damage or even death. Other potential infectious causes include anaerobic bacteria, gram-negative bacilli, and other pathogens. To minimize infection risk, anesthesiologists and technicians must adhere to strict aseptic techniques, particularly when managing immunocompromised patients.
Local Anesthetic Toxicity
Excessively high concentrations of local anesthetic in the bloodstream can lead to toxic effects on the central nervous and cardiovascular systems. Symptoms include dizziness, tinnitus, a metallic taste in the mouth, lightheadedness, seizures, coma, and cardiac arrhythmias. This is one of the most life-threatening complications of spinal anesthesia.
Pain at the Injection Site
Patients may experience tissue or ligament injury due to needle insertion during the procedure.
Other Side Effects
Common side effects include itching, nausea, and vomiting.
Due to its advantages—such as cost-effectiveness, intraoperative consciousness, faster postoperative recovery, and the avoidance of complications associated with general anesthesia and endotracheal intubation—spinal anesthesia is widely utilized. However, before opting for this technique, patients should consult a physician to assess potential postoperative risks.
3. Contraindications to Spinal Anesthesia
Spinal anesthesia is contraindicated in certain conditions due to potential risks and complications. These include:
- Cardiovascular conditions: Heart failure, severe mitral valve stenosis, severe aortic valve regurgitation, and myocardial ischemia
- Hemodynamic instability: Unstable blood pressure
- Neurological concerns: Spinal pain, headache, or congenital spinal abnormalities
- Allergic reactions: History of allergy to anesthetic agents
- Coagulation disorders: Patients on anticoagulant therapy or those with bleeding disorders
- Infection: Presence of infection at the puncture site
- Nutritional deficiencies: Severe malnutrition
About Tran Thi Anh Hien, MD
Tran Thi Anh Hien, MD completed her residency training and subsequently gained extensive experience at prestigious institutions, including Bình Dân Hospital, University Medical Center Ho Chi Minh City, and FV Hospital. She is currently a specialist in the Division of Anesthesia and Pain Management within the Department of Anesthesiology and Surgery at Vinmec Central Park International Hospital.
Dr. Duc Thong has 14 years of experience in Anesthesia and Resuscitation, including 12 years of dedicated service at the Department of Anesthesia and Resuscitation at C Hospital in Da Nang. Over the years, he has developed extensive expertise in anesthetic management for elderly patients, individuals with multiple comorbidities, and critically ill patients undergoing surgery. His expertise has been instrumental in the success of numerous complex and high-risk surgical procedures. Currently, Dr. Duc Thong serves as an anesthesiologist at the Department of General Surgery at Vinmec Da Nang International Hospital.
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