Complications
Since spinal anesthesia also paralyzes nerve fibers that control vegetative functions in the body, problems usually arise here. Frequently, blood vessels in the anesthetized parts of the body can no longer contract properly, resulting in a drop in blood pressure. To counteract this, the anaesthetist gives fluid by means of an infusion and administers supportive vasocontracting medication.
Once the effect of the anaesthetic wears off, this problem disappears again. In addition to the hypotension, the bladder often cannot empty itself properly, which can lead to urinary retention in the bladder, requiring the temporary insertion of a bladder catheter. This problem usually resolves itself over time.
Cardiac arrhythmia, nausea and vomiting can also occur. A much more dangerous complication is bleeding in the area of the spinal canal. This occurs more frequently in patients with a tendency to bleed or after the administration of blood-thinning medication.
Such bleeding can form hematomas that compress the nerve fibers and thus lead to pressure damage. In extremely rare cases, this complication can even lead to paraplegia. As with all invasive procedures, a needle stick during spinal anesthesia can also lead to infection.
In fact, however, infections during spinal anesthesia are a rarity. Neurological complications in the sense of damage to the spinal cord or nerves are also very rare, even if feared. More frequent, however, are the rather unpleasant so-called post-puncture headaches and back pain after the puncture.
What pain do I have afterwards?
Depending on the anesthetics used, spinal anesthesia eliminates pain in the body parts at the level of the puncture site and down from it for a period of about 1.5 to 6 hours. Only the sensation of pressure and the movement of the body parts should still be intact. Nevertheless, spinal anesthesia can also cause painful side effects.
Quite frequently, back pain occurs after the anaesthesia, for example, at the level of the puncture. It is possible for the pain to radiate into the legs or higher parts of the back. These can last for some time, but are ultimately self-limiting – after a few days the pain usually subsides without leaving any lasting symptoms.
In most cases, back pain after spinal anaesthesia is therefore harmless, but should still be mentioned during the next visit. Another typical complication after spinal anesthesia is headache. These are called post-spinal or post-puncture headaches and, similar to post-puncture back pain, improve in most cases after a few days without leaving any permanent damage.
Headaches after spinal anaesthesia are unfortunately a typical problem of the procedure. Among physicians, one speaks of post-spinal headaches, which are described in 0.5 – 18% of patients, depending on the definition, and which occur on average two days after spinal anaesthesia. Young women often suffer from headaches.
The development of headaches can be explained by the anatomical conditions in the spine and around the brain. During spinal anesthesia, the hard meninges (dura mater), which also coat the spinal cord in the spine, are punctured. Within the space surrounded by the hard meninges is the cerebrospinal fluid (liquor).
Now it is possible that during the puncture the dura is injured in such a way that it has not yet healed in the days following the puncture. If more cerebrospinal fluid then escapes than the body produces, the pressure in the cerebrospinal fluid space drops. This leads to CSF loss syndrome, which is assumed to be the cause of headaches after spinal anesthesia.
These are various mechanisms that cause headaches. The negative pressure causes stretching of sensitive nerve fibers and structures, which causes pain. In addition, the brain can slide down minimally within the skull, which causes venous vessels to be compressed.
As a result, the blood can no longer drain off sufficiently and thus cause increased intracranial pressure. This also causes severe headaches. This also explains why the pain is better when lying down than when sitting or standing.
In addition, a regulatory dilatation of the vessels is discussed.Probably an interaction of all mechanisms is responsible for the headache. However, it has to be said that post-spinal headaches have an extremely good prognosis and usually disappear by themselves without leaving any permanent damage. The treatment usually consists of the administration of classical headache medication (ibuprofen, paracetamol), bed rest and sufficient fluid intake.
If the headaches persist for a longer period of time, it can be assumed that the leak has not closed itself. In this case, it is possible to close the liquor leak with a blood patch consisting of a few milliliters of the patient’s own blood. The clotting of the blood closes the hole in the spinal cord skin, so that sufficient new water can be produced to allow the pain to subside.
By using special needles, the probability of headaches after spinal anesthesia can be reduced. It is important to ask the anesthesiologist during the consultation prior to spinal anesthesia whether you have ever suffered from this type of headache, as it is then likely to recur and possibly a different anesthetic procedure will be chosen. Unfortunately, back pain is a common side effect of spinal anesthesia – up to 10% of patients suffer from this type of pain.
For this reason, anaesthetists may decide against the procedure if the patient suffers from chronic back pain. The cause of the complaints has not been fully clarified to date and an exact assignment to the anesthesiological procedure, the operation or the positioning within the procedure is usually not possible. However, the good news is that back pain typically lasts only a few days and then subsides.
Back pain after spinal anaesthesia can also occur in combination with post-puncture headache. They can also be a symptom of the so-called “transient neurological symptoms” (TNS) – a rather rare complication of local anesthetics, which have a toxic effect on nerve fibers. The pain occurs within a few hours after application of the spinal anesthesia and subsides without consequences within days.
Neurological deficits and fever are classic symptoms of TNS. Finally, back pain after the puncture can also indicate an infection of the puncture site. Further signs of this would be neurological deficits, fever and reddening of the puncture site. However, infections during spinal anesthesia are a very rare complication.
