Severe neurologic injury: can epidural cause paralysis?

Can I get paralyzed from epidural?

Severe neurologic injury: can epidural make you paralyzed?

Severe neurologic injury leading to permanent paralysis is rare complication of epidural. It may occur as the result of epidural hematoma, epidural abscess or direct injury of the spinal cord. In rare instances unexplained neurologic injury may occur that cannot be attributed to epidural or spinal. The chance of suffering such injury as the result of labor epidural is rarer than the chance of suffering fatal car accident during the next year.

Pregnant patients are mostly young and healthy, and the risks of any procedures in this group must be seriously balanced against its benefits. What’s the point of relieving pain, even very intense, if the price of that will be becoming permanently paralyzed? The first commandment of medicine is Primum Non Nocere (first do no harm) has been formulated by Hippocrates thousands of years ago and is still valid today.

There is no point denying that serious neurological damage, such as permanent paralysis, can occur as the result of epidurals in labor or spinals for caesarean sections. However it is the unfortunate attribute of human mind that disasters tend to be given more attention than they deserve and are remembered for a long time, often out of context with the big picture. There are plenty of examples of this. After 9/11 disaster many people were terrified of flying, yet statistically air travel was and still is the safest – and most convenient – method of getting around. It was estimated that because more people chose to travel by cars, more death occurred on the roads than the average for the same period in previous years. Nobody was afraid of driving, even though death rate in traffic was considerably higher than in the air!

Paralysis resulting from labor epidural often gets a lot of attention from the media, and it does not help that the event inevitably becomes sensationalized. As the result the public gets wrong impression that these complications are more common that they are in reality. Of course, it would be wrong to blame patients for being suspicious and scared: the perspective of becoming disabled is terrifying.

Risk means different things for different people. Some of us engage in risky sports and activities, such as motorbike racing or bungee jumping, yet some refuse to drive because it is perceived as dangerous. Even though the risk of dying in plane crash is one in 10 million, some people still refuse to fly. The same is true for labor epidurals: you might refuse to take the slightest risk of being paralyzed. The acceptability of various risks is a deeply personal decision. And because it is influenced by strong emotions it is very important that the decision regarding labor epidural is based on the most comprehensive and latest information regarding.

Briefly stated, based on statistical data neuraxial blockade – labor epidurals or spinals for cesareans – are very safe. In rare instances however they can lead to neurologic damage.

Severe neurologic damage means the loss of function of the spinal cord or/and peripheral nerves that results in disability. The damage may be temporary or permanent. The accepted time for the return of function in temporary damage varies, but is generally accepted as one year. In other words if the patient does not recover within this time the damage is considered permanent. There are three ways by which epidural or spinal may inflict damage: direct injury, spinal hematoma or epidural abscess.

Direct injury is the result of the placement of the epidural needle into the spinal cord or nerve root. The degree of damage varies depending on the depth of the penetration of the needle and, if an injection was done, the characteristics and the volume of the drug. This type of damage is probably the most uncommon, mostly because when the needle touches the spinal cord or a nerve it causes pain so severe that the patient immediately reacts to it and will simply not the anesthetist to continue the damage, thus limiting the injury to the minimum.

Spinal hematoma occurs in patients in whom the ability of blood to coagulate is impaired. Epidural space is filled with veins which are commonly injured during the placement of epidurals. In vast majority of patients it is not a problem: the bleeding triggers the cascade of biochemical reactions the result of which is blood clot which plugs the hole on the vessel and stops the bleed. If for some reason the formation of the clot is impaired the bleeding continues. Spinal canal is an enclosed space surrounded by hard bony tissue that cannot expand, and if the bleeding continues the blood fills the canal and leads to the compression of the structures within it, most importantly the spinal cord. Blood supply to spinal cord becomes compromised, and if the compression lasts for longer than six to eight hours the damage is likely to become permanent.

Epidural abscess is the result of infection, and the mechanism of injury in this case is similar to that of epidural hematoma. The infection expands within the spinal canal and either causes the compression of the spinal cord. In addition, neural structures are directly damaged by infection. Epidural abscess takes longer to produce damage than hematoma: days, weeks or even months.

Obtaining statistics regarding these complications is difficult, and the reliability of the existing data can be debated either way due to several reasons. First, the incidence of these complications is rare, and in many labor wards decades pass without one happening. Many cases of permanent damage may not be reported in the literature if litigation process has been initiated. Existing data is also difficult to interpret: most reports of the damage come from academic institutions where most epidurals are performed by junior doctors in training. Experience of the operator by itself is a major factor determining the risk of medical procedures, therefore the statistics of complications is likely to be distorted. Lastly, statistics of epidural or spinal complications most often include patients from all areas of surgery, not only laboring women, and those patients have considerably higher risk of epidural complications, including the serious ones. The inclusion of these patients in overall epidural statistics most certainly creates falsely inflated incidence of severe neurological complications in obstetric patients.

What follows is the detailed discussion of three scenarios leading to severe neurological injury: epidural hematoma, epidural abscess and direct damage of the neural structures.

Epidural hematoma

As already mentioned, injury of small blood vessels during the insertion of the epidural needle is common and does not cause problems. In healthy people the injury of small blood vessels and the resulting bleeding is self limiting. The reason is the ability of blood to form a clot, or coagulate. The clot plugs the damaged blood vessel and stops the bleeding.

The blood consists of the liquid part – plasma – and cells: red and white blood cells and platelets. The biochemistry behind coagulation is very complex but may be reduced to two major components: the platelets and dissolved in plasma proteins called coagulation factors. As soon as the tissue is damaged the platelets start getting stuck to the damaged site. This process is called adhesion. Activated platelets change their shape from spherical to star-like and acquire the ability to bind with fibrinogen. At the same time the specific biochemical factor released from the damaged cells – tissue factor – triggers the sequence of reactions in plasma called coagulation pathway, the final result of which is the conversion of soluble protein fibrinogen into insoluble fibrin, which looks like strands made of cooked egg white. Together with platelets fibrin forms the clot.

There are two major groups of causes of decreased ability of blood to coagulate: congenital or acquired. Immediate examples of congenital conditions that come to mind are hemophilia and Von Willebrand’s disease. In both of these conditions certain coagulation factors are absent due to genetic defects. Depending on the severity of the condition, some hemophiliacs can literally bleed to death from a small cut, as well as to lose large amount of blood from an injury that would normally cause a small bruise in a healthy person. Luckily, these diseases are uncommon. However there are other, less dramatic conditions, in which blood coagulation is impaired.

Acquired coagulation disorders are even rarer, and most of them are the result of medication specifically given to reduce the ability of blood to coagulate to various degree, most commonly for the prevention of blood clots in the deep veins in the legs. Some examples of such drugs are aspirin, heparin, clexane, warfarin, clopidogrel and a few others.

Obviously, the first step to prevent epidural hematoma is to identify patients at risk of impaired coagulation. Identifying patients on anti-coagulant medication: we simply ask about it. The patients with hemophilia and other severe bleeding disorders are spotted in the same way. It is more difficult to identify those with less obvious disease, and for that purpose several focused questions are asked: do you tend to bleed a lot from small cuts, did you ever need a blood transfusion and in what circumstances, and so on. Whatever the cause, if the ability of blood to coagulate is impaired – the condition collectively called coagulopathy – neuraxial analgesia is contraindicated.

There is a specific subgroup of obstetric patients in which coagulopathy may be present, women with pre-eclampsia. This condition affects between two and three percent of all pregnant women and is characterized by two main features: elevated blood pressure and the presence of proteine in the urine. Headache is usually the main symptom. Severe and/or untreated pre-eclampsia may develop into eclampsia – generalized seizures – which may be fatal. In the vast majority of patients pre-eclampsia is controlled relatively easily. However in severe cases patients are unresponsive to medication, and early termination of pregnancy becomes the only option. As many of pre-eclamptic patients have high blood pressure, the use of epidural analgesia in labor is beneficial: good pain control prevents extreme and dangerous swings in blood pressure. Similarly, for those pre-eclamptic patients who require cesarean section spinal anesthesia is preferred for the same reason.

To make the situation (and lives of anesthetists!) more difficult, pre-eclampsia may be complicated by HELLP syndrome. HELLP syndrome is the acronym for Hemolysis, Elevated Liver enzymes and Low Platelets. Hemolysis is the condition where red blood cells become damaged and their content is present in plasma. If severe it can lead to kidney damage. Elevated liver enzymes are the result of liver damage. The patients with this syndrome commonly complain of pain in the upper part of the abdomen – the area where the liver is located. Hemolysis and liver damage are serious enough conditions to raise the alarm of doctors, however it is the third part of the syndrome, low platelets, that are of the particular importance to an anesthetist, and this the situation may get tricky.

As explained above platelets are vital for normal coagulation process. If platelets are low the risk of bleeding increases, and if epidural or spinal is performed the risk of epidural hematoma increases many times. It is generally acceptable that the safe concentration of platelets in respect to neuraxial block is 100,000 per 1 mm3, and in some cases up to 70,000. Below this level the risk becomes unacceptably high. Most anesthetists consider the rate of decrease more important than the actual number. If platelet count is 90,000 for the last three days most anesthetists will go ahead with the epidural, but will not do it if the count goes down from 120,000 to 100,000 in the last couple of hours. Such an aggressive drop indicates aggressive disease process, and in such cases it is better to stay away from neuraxial blocks.

The problem is that for patients with pre-eclampsia and HELLP syndrome spinal or epidural is the best anesthetic choice. Even the most naturally oriented midwives support epidurals in these patients due to their beneficial effects on blood pressure. Paradoxically, the more severe the condition, the more desirable the epidural becomes. The same is true for those who undergo caesarean section: spinal anesthetic allows for much better and more predictable blood pressure control during surgery in these patients.

There is more to HELLP syndrome. Patients suffering from this condition commonly develop edema – swelling – of the upper respiratory tract. This increases the incidence of difficult intubation during general anesthesia, which may ultimately lead to inability to maintain adequate respiration and oxygenation. Spinal anesthetic eliminates the risk of failed intubation by keeping the patient awake.

At the end of the day the decision to proceed with the epidural or spinal is made after weighing all risks and benefits: platelet count, the rate of its decrease, the degree of blood pressure elevation, anticipated difficulty of general anesthesia for a particular patient and other relevant factors. Most importantly, the decision is made with full participation of the patient after explaining the situation.

If the hematoma does occur it manifests with the following symptoms:

  • progressive back pain
  • failure to regain sensation and/or motor function in the legs after the removal of epidural catheter
  • new changes in sensation or motor function.

If the bleeding in the epidural continues the sensation and movement in the lower limbs worsens and eventually full paralysis occurs. On physical examination the weakness and loss of sensation is confirmed. Peripheral reflexes (such as knee-jerk reflex) may be increased. Diagnosis of spinal hematoma is based on symptoms and signs and is confirmed by imaging investigations, such as Magnetic Resonance Imaging, or MRI.

Epidural hematomas as a complication of neuraxial block are only part of the picture, as most of hematomas are spontaneous and are dealt with by neurosurgeons on regular basis. In some cases epidural blood vessels can rupture spontaneously, due to the weakness of vascular wall and elevated blood pressure. They can also result in various degrees of neurological symptoms and are treated according to the situation. While most spontaneous hematomas are managed conservatively, hematomas resulting from epidurals must be treated by surgery. The speed of intervention is crucial for adequate recovery, and the sooner hematoma is drained, the more likely full recovery. It is generally accepted that spinal hematoma must be surgically drained within eight hours in order to avoid permanent damage. That is why the patients with the slightest suspicion of this complication are immediately sent for an emergency MRI.

Now to the most important question: what is the actual risk of spinal hematoma?

One of the most comprehensive reviews on epidural hematoma complicating epidural anesthesia has been performed by Erik Vandermeulen and colleagues in 19941. The first part of the article discussed problems related to obtaining reliable data. If this complication was to be studied in a prospective and randomized study, its design would be ethically and methodologically difficult, and would require analysis of more than 100,000 patients. Just to put this number into perspective: one of the regional hospitals where I work performs about 1000 to 2000 deliveries a year with about twenty percent of patients (400) getting epidurals. Imagine how long it would take to get enough data for proper analysis. The review quotes several publications of large case series in which epidural or spinal anesthesia was performed without a single spinal hematoma. In some publications more than 200,000 patients received uncomplicated epidural blocks, while fewer uneventful procedures have been described after spinal anesthetic. One published review evaluated 13 case series that included more than 850,000 patients having received an epidural block. Only three patients developed spinal hematoma. Similarly, seven other case series were reported, including 650,000 spinal blocks without a hematoma. Using statistical analysis it was estimated by some authors that the risk for a spinal hematoma to be 1:150,000 after epidural and 1:220,000 after spinal. Estimated figures in epidemiological studies are presented as confidence intervals: the lowest and the highest probabilities that would include 95% of cases. Figures quoted in the study represent the upper limits of the confidence interval, so that the real incidence values will probably be somewhat less frequent.

Vandermeulen’s review summarizes published cases of epidural hematomas and summarized risk factors associated with this complication as well as to identify possible causes. It is based on the literature search through the National Library of Medicine’s MEDLINE system and assessed previously published major reviews and large case series and found cases of bleeding complications of the spinal cord associated with epidural or spinal anesthesia. Between 1906 and 1994 – the span of 88 years – 61 published cases of epidural hematoma were found that developed after epidural or spinal anesthesia.

42 of 61 spinal hematomas (68%) occurred in patients with impaired coagulation. In 25 of them some form of heparin therapy was present. The remaining 12 patients had a variety of conditions, including thrombocytopenia (low platelets), chronic alcohol abuse, chronic renal insufficiency, or were treated with aspirin, indometacin, urokinase, phenprocoumone, dextran 70, or other drugs that are known to interfere with coagulation. Among patients with spinal bleeding were five pregnant women and four patients with anatomic abnormalities of the spinal cord or the vertebral column, such as tumors rich in blood vessels. The puncture – epidural or spinal block – was reported difficult in 15 and/or bloody (signifying definite blood vessel injury) in 15 patients, respectively (25%). Multiple attempts were reported in 12 patients (20%). Hence, in 53 of the 61 cases (87%), at least one of the above-mentioned conditions – clotting disorder or technical difficulties – was present. More than one of the above conditions was found in 20 cases.

As mentioned before, if a serious complication following spinal or epidural block has been the subject of a legal process these cases don’t get reported in the literature for obvious reasons. Analysis of indemnity insurance claims helps to overcome this problem to some degree. Every doctor has indemnity insurance, and if he or she is sued by a patient the insurance covers litigation costs and settlements if such arise. Studying insurance claims gives allows to look at those cases that are not likely to be reported in the academic press. One such study was conducted in Finland. In 1987 Finland introduced the Patient Injury Act, according to which a patient suffering any injury as a result of medical treatment may file a claim to the Patient Insurance Association. From 1 May 1987 to 31 December 1993, 23 500 claims for compensation were made. After going through the claims database the authors of the review found 86 claims where spinal or epidural anesthesia was involved. Unfortunately there was no distinction made between epidurals and spinals that were performed for childbirth or other types of surgery. Altogether seven claims were made for long-lasting motor and/or sensory deficits. The duration of the complaints ranged from 3 months to permanent. Fifteen patients filed claims for long-lasting sensory loss or painful areas in the buttock and/or legs. On the average the symptoms persisted from 6 months to 2 years. There were several cases of permanent paralysis as well, but none of them was clearly related to epidurals in labor.

The authors of the review estimated that during the period during which claims have been made 550,000 spinals and 170,000 epidurals were performed, and the incidence of any serious complications therefore was 0.45 per 10,000 for spinal and 0.52 per 10,000 for epidural anesthesia. The definition of serious complications in this study included not only neurologic complications but other events, such as cardiac arrest, acute toxic reaction to local anesthetic drugs and bacterial infections. On the other hand, seven claims for neurological deficit translate to about one case per 100,000 neuraxial blocks, the rate consistent with the previous review. The authors of the review also concluded that careful patient selection and proper technique are of importance in order to avoid serious complications related to epidural or spinal blocks.

The most current and the most relevant for our discussion review on severe neurological complications after epidural and/or spinal block has been published in 2006. It specifically looked for reports of epidural hematoma, abscess and neurologic injury in obstetric patients who had epidural for labor or spinal anesthetic for cesarean section. The review covered published literature from 1966 to 2005. Initial search found 1269 articles on the subject, 38 were related to obstetrics. Eventually 27 methodologically solid studies were selected for the final analysis of data.

Eight studies with the total patient population of 1.1 million reported a total of six epidural hematomas. This number, six hematomas in over a million epidurals , illustrates the difficulty of studying this complication and calculating the chances of it happening. Unfortunately the studies did not report the management and the outcomes of these complications. These numbers give an estimated incidence of epidural haematoma as 1 in 168,000 to 183,000 or 5 to 6 per one million patients.

Epidural abscess

If infection is introduced into a tissue it triggers a complex immune response. Various immune cells move to the infected area, eventually surrounding and destroying infectious bacteria. This process is accompanied by pain, redness of the area as the result of dilatation of blood vessels, swelling and, in cases of more severe infection, systemic symptoms such as fever, malaise and chills. In the attempt to limit the spread of infection the immune process results in bacteria being encased in a cavity which eventually drains to the surface and heals. Common acne vulgaris – a skin pimple – is a typical example of the workings of the immune system. The infection originates in the sebaceous gland of the skin, immune cascade is triggered, the infection become localized in a small cavity and eventually finds its way to the skin. Infected content of the cavity consisting of dead bacteria and immune blood cells – pus – is eventually evacuated and the cavity heals. Such cavity is called an abscess.

Depending on the function of the immune system and the aggressiveness of bacteria infection may spread to the surrounding areas tissues and cause considerable damage. Abscesses situated in deep areas – abdomen for example – cannot be drained spontaneously and are treated by surgery: an incision is made, the pus drained and the cavity washed out with antiseptic solutions.

Epidural space is filled mostly with fat tissue which is generally characterized by poor blood supply. It is also located far from the skin. If infection is introduced into the epidural space it may form epidural abscess, the cavity filled with pus. The damage from epidural abscess is twofold: compression of the spinal cord and other neural structures by the expanding cavity similar to that in epidural hematoma, as well as direct damage by infectious bacteria. Infection can also spread to the vertebrae, resulting in osteomyelitis, or bone sepsis, the condition that is difficult to treat.

The progression of the epidural abscess follows four basic stages:

Stage 1 – back pain at the level of affected area

Stage 2 – nerve root pain radiating along distribution of the nerves

Stage 3 – impaired sensation and motor function, urinary and bowel incontinence

Stage 4 – paralysis.

Because of the poor blood supply of the epidural space the delivery of the immune cells is slow and so is the development of symptoms which are also often vague. Back pain is seen in three quarters of patients, fever in about half and early neurological symptoms occur in one third of patients. All three symptoms are present only in a small minority of patients. The duration of symptoms may vary from several of days to several months.

Spinal abscesses usually extend over the level of three to four vertebrae, but in very rare cases may involve the whole spine. Patients who have diabetes, history of alcohol or substance abuse as well as HIV-positive persons are at significantly higher risk of developing epidural abscess. The diagnosis of an epidural abscess is made on the basis of symptoms and signs and is confirmed by CT-scan or MRI.

Slow progression of epidural abscesses is both a blessing and a curse. On one hand the damage takes longer time to occur and allows for considerably more time for intervention. On the other hand, because the symptoms are developing slowly and are often not dramatic the diagnosis of epidural abscess is often delayed until serious neurological complication develop. At early stages of epidural abscess patients often complain of some back pain, sometimes radiating pain to the leg(s) and mild fever. Back pain and nerve root irritation are common during and after pregnancy. Mild fever typical for epidural abscess is also common in the weeks following delivery. Because of vague presentation up to half of the patients with epidural abscess are initially misdiagnosed, according to clinical data.

Education of patients is crucial for early diagnosis, and every woman who had labor epidural should be aware of the potentially serious symptoms. If symptoms occur it is important to emphasize the history of recent epidural to the attending doctor. Even better, the patient should contact the anesthetic department of the hospital where epidural was given. Anesthetists are literally paranoid about serious complications of epidurals and will follow symptoms even remotely suggestive of epidural abscess with vigilance, often excessive. Vast majority of anesthetists will insist on immediate MRI. Most of the time there will be no pathology found, however the motto is “rather safe than sorry”, and such vigilance ensures that epidural abscess is not missed. MRIs are safe, and except for being expensive there are no serious side effects from this investigation.

The treatment of epidural abscess consists of two parts: removal of pus – drainage – and antibiotics. Drainage is done surgically and may be extensive if infection spreads to the surrounding tissues, such as bones, ligaments and muscles, as all infected tissues must be removed if possible. Antibiotics are started immediately and continued for a long time to prevent the recurrence of infection. There are reports of successfully treated cases of epidural abscess without surgery, with antibiotics alone. However this approach is only suitable when minimal symptoms are present and when the risk of infection spreading is low. Ultimately the surgeon will decide on the approach based on the severity of the abscess, the condition of the patient and estimated risk of recurrence.

The outcome of treatment depends, first and foremost, on the severity of the infection as reflected by the symptoms. Abscesses detected in early stages are small and easy to drain. They are also less likely to spread and cause extensive damage. This explains clinical aggressiveness of anesthetists when this complication is suspected. If a woman presents of moderate back pain several days after she had an epidural and is subsequently diagnosed with the abscess on the MRI, severe disability is unlikely if adequate treatment is initiated. On the other hand, if neurological symptoms are – muscle weakness, loss of sensation or incontinence – are already present, the chances are that at least some symptoms will remain after treatment. In general, paralysis is likely to become permanent if it lasts longer than 24 hours.

Fortunately, the chances of epidural abscess are low. According to the data from the review mentioned in the previous section, the incidence of epidural abscess is slightly higher than epidural hematoma. 13 studies that included the total of 1.2 million women with labor epidural reported 11 cases of deep epidural abscess. This gives estimated incidence of 1:110,000 women, or 9 cases per one million patients. Studies conducted after 1990 report slightly lower incidence of 1:145,000 women, or 7 per million.

Unfortunately, final outcomes of epidural hematomas and abscesses are often not reported in published studies, therefore it is impossible to estimate the risk of disability. According to published literature on all epidural abscesses, not only those related to epidural blocks, 4 to 22% of patients end up with permanent paralysis. Early diagnosis remains the most important factor that determines recovery.

Direct neurologic damage

Anything involving a sharp object inserted into a human body carries risks. Epidural block is performed in a blind fashion, and the position of the needle is determined by the loss of resistance to air of saline. The fact is that on the way between the skin and epidural space there are no important anatomical structures damage to which can lead to serious consequences. However, at least theoretically the needle can end up in nerve roots or spinal cord and result in neurological injury.

There are no reviews specifically addressing direct injury to neural structures during epidural or spinal. The technique of neuraxial anesthesia has been perfected and standardized on literally millions of epidurals performed over the last several decades. The equipment has also evolved during the same period of time. Teaching standards and safety expectations have also improved considerably, therefore it is not surprising that direct injury to the spinal cord and nerve roots is rare. In fact, it is so rare that the only information regarding this complication available in published literature consists only of case reports, and estimation of a meaningful value of risk is not possible.

The most important and reliable “safety monitor” during placement of epidural is the patient herself. It is the absolute requirement that when epidural or spinal is performed there should be no significant pain. Injecting local anesthetic under the skin causes burning sensation, and advancing epidural needle through tissues may cause discomfort, however it must not cause serious pain. Sharp pain, especially if it irradiates into the legs or the side of the body, means the contact between the needle and neural structures. Most of us are familiar with intense shooting pain similar to electric shock when a “funny point” on your elbow is struck. Needle touching a nerve causes similar sensation, and the patient will immediately let the anesthetist know of this happening, who will stop advancing the needle at this point.

Contact with nerve roots is relatively common when epidural is performed, especially during the placement of epidural catheter. By itself it is harmless and does not cause any more problem than unpleasant sensation. If pain occurs the anesthetist should withdraw the catheter and change the position of the needle before attempting advancing the catheter again. The same is true when local anesthetic mixture is injected through the catheter: it must NOT be painful.

During placement of spinal block for cesarean section the feeling similar to electric shock passing through the leg(s) is relatively common and once again is due to the needle touching the nerves of the cauda equina. Spinal needles are small in diameter and relatively blunt, and limited contact with the nerves is harmless. Typically the patient feels momentary pain, not intense, shooting through to one of the legs. The pain disappears immediately. On the other hand, pain during actual injecting of local anesthetic is unacceptable. The injection must be stopped and the position of the needle changed.

In medicine nothing is infallible, and there have been reports of cases where full dose of local anesthetic intended for intrathecal block has been injected directly into the spinal cord without the patient feeling any pain. Needless to say such cases are an aberration and are extremely rare.

Unexplained injury

Some neurological damage that persists after labor epidural cannot not be clearly attributed to either epidural hematoma or infection. It has been termed as persistent neurologic injury. Its estimated incidence is between 1:257,000 and 1:237,000, depending on the reporting period, or 4 per one million patients. The causes of these complications are not clear. Childbirth is a traumatic process and may be accompanied by significant tissue damage. When the fetus passes through the birth canal it may cause considerable pressure on lumbar plexus – the nerves that supply the thighs and knees – on one or both sides. If labor is prolonged and there is a significant disproportion between the head of the fetus and woman’s pelvis injury to the lumbar plexus can occur with various degrees of loss sensation and motor function in the legs.

There are many possible causes of neurologic deficits, and all of these rare complications could occur spontaneously. There are several reports of spontaneously occurring epidural hematomas and abscesses during pregnancy and childbirth. One study reported 95 cases with neurologic damage in obstetrics with and without epidurals. It was found that 85% of cases of neurologic damage occurred with forceps delivery.

Overall incidence of severe neurologic complications after labor epidural and spinal for cesarean is low, roughly between 1:100,000 and 1:250,000. The very purpose of this site is to provide the user with an understanding of risk of complications, and it is best achieved by comparison with something familiar. According to the National Highway Traffic safety Administration (http://www-fars.nhtsa.dot.gov/Main/index.aspx) in 2008 in the United States there were 17.96 fatalities per 100,000 registered drivers, or 12.3 per 100,000 of population. Either of these figures is more than ten times the incidence of severe neurologic injury after epidural. In less densely populated (and maybe more law abiding) Australia (http://www.bitre.gov.au/publications/49/Files/IS38_RoadDeathsB.pdf), road mortality has been reported at 7 per 100,000 of population in 2007, still considerably higher than the rate of neurologic injury after labor epidural. Despite of the fact that the chance of dying while driving to work driving is significantly higher than becoming paralyzed after epidural the latter causes considerably more anxiety and fear.

It is undeniable that every medical procedure is associated with risk of serious complications, and labor epidural is no different from other interventions. It is not sufficient to mention the risk of a complication, its severity and the impact is also very important. At the end of the day acceptance of risk is a personal decision which should be based on the best available information. Providing this information is the primary purpose of this site.

References:

Vandermeulen EP, Van Aken H, Vermylen J. Anticoagulants and Spinal-Epidural Anesthesia. Anesth Analg 1994;79:1165-77

Aromaa U, Lahdensuu M, Cozanitis DA. Severe complications associated with epidural and spinal anaesthesias in Finland 1987-1993. A study based on patient insurance claims. Acta Anaesthesiol Scand. 1997 Apr;41(4):445-52.

Ruppen W, Derry S, McQuay H, Moore RA. Incidence of Epidural Hematoma, Infection, and Neurologic Injury in Obstetric Patients with Epidural Analgesia/Anesthesia. Anesthesiology 2006; 105:394–9.

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Dr. Eugene Smetannikov is a practicing anesthesiologist with the interest in obstetric anesthesia. He is the author of the most comprehensive book on the subject, The Truth About Labor Epidural