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Chiari malformations can come to light – or “present”, to use medical terminology – at any age, from childhood to later life. The most commonly affected age (or “peak incidence”), however, is the early part of adult life. Women are affected more often than men, in a ratio of about two-to-one. This means, that many ladies with Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described – see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms. may plan to become pregnant when already knowing that they have a Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described – see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms., with or without an associated syringomyeliaA cavity, within the spinal cord, which is filled with cerebrospinal fluid. Syringomyelia cavities come in various “shapes and sizes”, from short, spindle-shaped cavities through to long, tense cavities extending throughout the greater part of the spinal cord. Read more.
Most people with Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described – see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms. will know, from personal experience, about the so-called “pressure dissociation” headaches that are so characteristic of the condition. Typically brought on by coughing, sneezing, straining, laughing or bending over, these headaches, although short lived, are very intense and unpleasant. Most mothers-to-be will also know about what is involved in childbirth, in terms of “bearing down” – what obstetricians call the “second stage of labour”. It is no wonder, therefore, that both obstetricians and their patients can become concerned that natural childbirth – i.e. a normal “vaginal delivery” – might be an unpleasant experience for the mother, if not even a risky one.
In the past, when approached by obstetricians for help on this matter, neurosurgeons tended to advise against normal delivery, for pregnant ladies who were known to have a Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described – see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms.. Caesarean section was favoured instead. In recent years views have changed and it is now often suggested that a pregnancy can be managed along normal obstetric lines. Such advice, however, is dependent upon a full understanding of the individual mother’s neurological condition and the state of her internal anatomy in relation to her Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described – see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms., as well as the state of any associated syringomyeliaA cavity, within the spinal cord, which is filled with cerebrospinal fluid. Syringomyelia cavities come in various “shapes and sizes”, from short, spindle-shaped cavities through to long, tense cavities extending throughout the greater part of the spinal cord. Read more. In the latter case the size of the cavity may have a bearing upon the advice offered.
Another question that arises in relation to childbirth is the use of epidural anaesthesia. This form of pain control relies upon the spinal nerves being bathed in local anaesthetic, injected outside the membranes lining the spinal canalThe individual bones that comprise the spinal column are made up of a weight-bearing “body” and other components which, together, form a ring of bone, behind the body. These individual vertebrae, joined together as the spinal column, therefore, create a canal running down the entire length of the spine.. From time to time, however, the needle used to inject the anaesthetic can inadvertently puncture these membranes, resulting in leakage of the cerebrospinal fluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at… which bathes and supports the brain and spinal cordThe main nerve trunk running down the spinal canal and connecting the individual’s mind and consciousness to the rest of his or her body. It is about the size of a person’s little finger, in diameter. It cannot repair itself if damaged.. The resulting loss of buoyancy may cause the brain to “slump” somewhat, causing the cerebellar tonsilsThe lower-most part of the cerebellum is made up of a pair of structures, one on each side of the midline, known as the tonsils. These structures have no relationship with the tissue at the back of the throat, which becomes inflamed and sore with a viral infection. It is simply the case that the same Latin term was applied by (presumably) different anatomists, at different times and working in different places, to name these very different body parts. The word tonsilla literally means a stump; Roman ships were moored to “tonsilla” when in port. to impact further into the foramen magnumThe large, ovoid opening at the base of the skull, measuring about 3 x 3.5cm, through which the spinal cord passes, to continue on as the brain stem.. The concern then is that such movement could lead to potentially harmful, even lethal compression of the brain stemThis is the most primitive part of the brain, connecting the rest of the brain to the body, via the spinal cord. In addition to feeding signals to and from such “higher centres”, the brain stem contains a number of important control centres, regulating vital functions such as breathing and blood pressure.. In truth, there is debate amongst neurosurgical experts as to just how great are such risks but obstetric anaesthetists will often seek advice from neurosurgeons on this question.
As ever, the Ann Conroy Trust cannot and does not offer advice to individual patients on matters such as these. We nevertheless hope that these notes will help expectant mothers with Chiari and/or syringomyeliaA cavity, within the spinal cord, which is filled with cerebrospinal fluid. Syringomyelia cavities come in various “shapes and sizes”, from short, spindle-shaped cavities through to long, tense cavities extending throughout the greater part of the spinal cord. Read more to understand some of the issues in question. The important point is that the health professionals supervising the pregnancy – midwives, obstetricians and anaesthetists – are made aware about the Chiari/syrinx, so that they can liaise with the mother’s neurosurgeon (or an appropriate neurosurgeon) and decide upon the best way of managing the forthcoming birth.