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Spinal anesthesia

Brian W. Launius, M.D.

Over many years, the specialty of Anesthesiology has continued to evolve with more effective ways of allowing patients to undergo complex surgeries safely. Yet, one very simple procedure, known as “the spinal,” continues to be used as a low-risk, reliable form of anesthesia.

The following review of this classic anesthetic, being used in some of today’s most modern surgeries, is meant to be informative in case you wish to consider the spinal option for any future surgery.

The first documented surgery performed under spinal anesthesia occurred in Germany in 1898. The idea that surgery below the “belly-button,” or umbilicus, could be performed painlessly, without the dangers of total unconsciousness, was revolutionary. In the 20th century, spinal anesthesia was utilized for a wide variety of surgeries in millions of patients throughout the world. Today, it is favored in many orthopedic surgeries of the hip, knee and leg; surgeries of the lower abdomen such as hernia repairs; and pelvic surgeries such as hysterectomies, prostate or bladder operations, as well as C-sections.

In simple terms, spinal anesthesia involves the sterile injection of a local anesthetic into the sac of spinal fluid surrounding the spinal nerves and spinal cord. The effect of this interrupts, or “numbs” any sensation of pain from the area of surgery.

Spinal anesthesia usually is performed in the operating room, along with some form of sedation to relieve anxiety. After receiving the anxiety-relieving sedation, most patients are unable to recall, or have only a vague recollection of, having the spinal placed.

Before placing the small spinal needle in the low back, the anesthesia provider performs a sterile “scrub” of the back and numbs the skin with a local anesthetic. The needle is placed between two of the lumbar vertebra and advanced carefully until a small amount of spinal fluid is seen. The anesthesia provider then injects a small amount of local anesthetic in “single-shot” fashion without leaving any needle or apparatus behind.

Within minutes, the patient’s lower body becomes warm, heavy and without feeling. For most surgeries, this feeling of numbness will last for several hours – long enough to complete the surgery. In certain cases, the spinal medication also may include a longer-acting narcotic for providing pain relief even after the spinal numbness has gone away.

After surgery, the patient is observed in the recovery room for several hours as the numbness of the spinal anesthetic recedes and the presence of any side-effect is monitored.

One of the most unique side-effects of the spinal, noted even during its discovery in the 19th century, is the “spinal headache.” During the first 70 years of spinal anesthesia many suffered this headache and there was no effective treatment other than passage of time.

For some present-day patients, this concern of a possible headache has caused them to view the spinal as an unpleasant option. Fortunately, anesthesiologists now have a better understanding of how spinal headaches occur. Smaller, less traumatic spinal needles have been developed making spinal headaches very unlikely, especially in patients beyond middle-age. In the rare event a patient does develop a spinal headache there are quicker, more effective treatments to alleviate any headache discomfort.

Another concern that may prevent patients from choosing a spinal anesthetic is the fear of nerve or spinal cord injury. Because the spinal needle is placed below the level where the spinal cord has ended, risk of injury or paralysis is extremely rare.

Other possible side-effects of spinal anesthesia may include a drop in blood pressure. In many cases, lowering of patients’ blood pressures during surgery helps in minimizing blood loss. Those patients who are dehydrated, in shock, or have severe disease of the heart, however, may not be candidates for a spinal anesthetic, due to the blood pressure concern.

Patients who currently are taking “blood-thinning” medications such as Coumadin or Plavix are often not given the option of a spinal anesthetic. This is due to drug-use cautions which all Coumadin/Plavix-users should be aware of, concerning the risk of excess bleeding during spinal needle puncture.

Other conditions that would prevent the choice of a spinal anesthetic include active infection in the bloodstream or low back, previous back surgery or curvature of the spine, and of course, a patient’s refusal to have a spinal anesthetic.

Lastly, the planning of a spinal anesthetic between patient and anesthesia provider also will include a secondary plan of appropriate deeper sedation or general anesthesia in case is it needed. As anesthesia providers, it is our job to listen carefully to your history, as well as your desires and concerns, guiding you to a plan of anesthesia to meet your specific needs during your surgery.

Brian W. Launius, M.D., joined VVMC’s Medical Staff in 2009. He is certified by the American Board of Anesthesiology and is a member of several professional societies including the American Society of Anesthesiologists.