Surgery For Chiari Malformation In Adults
This malformation occurs during fetal development and is characterized by downward displacement by more than four millimeters, of the cerebellar tonsils beneath the foramen magnum into the cervical spinal canal. This displacement may block the normal pulsations of CSF between the spinal canal and the intracranial space. This form of Chiari malformation may be associated with syringomyelia/hydromyelia. It is diagnosed more commonly in adolescents or adults.
surgery for chiari malformation in adults
Chiari I malformations that are asymptomatic should be left alone (this involves the majority of Chiari malformations). There is no indication for "prophylactic" surgery on these. If the malformation is defined as symptomatic, or is causing a syrinx, treatment is usually recommended.
There are many different types/extent of surgery based on the extent of compression or other anomalies. Chiari I malformations may be treated surgically with only local decompression of the overlying bones, decompression of the bones and release of the dura (a thick membrane covering the brain and spinal cord) or decompression of the bone and dura and some degree of cerebellar tissue resection. Occasionally some patients will also require cervical spinal fusion.
In the most common surgery for Chiari malformation, called posterior fossa decompression, the surgeon removes a small section of bone in the back of the skull, relieving pressure by giving the brain more room.
Many patients ask about minimally invasive or endoscopic surgery. Minimally invasive can mean different things: shorter skin and muscle incision, no dura opening, no shrinkage of the tonsils, or use of ultrasound and endoscopes. Despite what the words "minimally invasive" suggest, the amount of bone removal needed to effectively restore normal CSF flow depends on the individual patient's anatomy and size of Chiari. The amount of bone removal should be the same in any procedure, endoscopic or standard "open" technique. It's also important to understand that some minimally invasive techniques used for children (whose skulls are still growing) may or may not be appropriate for adults.
The results of your decompression surgery depend on the severity of the Chiari malformation and the extent of any previous brain and nerve injury before treatment. Eighty five to 95% of patients experience major relief of symptoms . However, patients may continue to have residual symptoms from syringomyelia. If injury in the spinal cord has already become permanent, surgery won't reverse the damage.
Mayfield Brain & Spine evaluates more than 80 adults affected by Chiari malformation each year. Some people only require monitoring, but many need decompression surgery to enlarge the bony opening, restore normal fluid circulation around the brain, and prevent a syrinx.
When it comes to Chiari malformation treatment, there are generally two approaches a surgeon may use: traditional surgery or minimally invasive. Traditional surgical procedures are what you would think of as open surgery and include Chiari decompression surgery and cervical laminectomies, which have been used by many doctors to effectively treat Chiari malformation patients. However, new advances in technology and techniques have made minimally invasive Chiari malformation treatments possible. In a minimally invasive surgery, the surgeon uses specialized instruments that allow him or her to make smaller incisions and disrupt less of the surrounding tissues.
Most patients who are candidates for traditional Chiari malformation surgery are also eligible for minimally invasive approaches. In fact, many Chiari malformation specialists have come to prefer using minimally invasive treatments because they are just as effective as traditional surgery, with increased benefits to patients.
As a patient, minimally invasive treatments means that you can expect to experience less bleeding, less pain and a shorter recovery period. Your hospital stay following a minimally invasive Chiari malformation procedure will typically be shorter than traditional open surgery. You will likely require less pain medication and/or need medication over a shorter duration. You may also be able to return to work and resume your normal activities more quickly, although recovery is a very individual process and varies from patient to patient.
Forty adult patients (average age 40 years), with the clinical and radiological features of the Chiari malformations, were seen at the Toronto Western Hospital between 1967 and 1984. Surgical confirmation of the diagnosis was obtained in 32 cases; of these, 23 were classified as Chiari I malformation while 9 fulfilled the anatomic criteria of Chiari II. The patient population consisted of 22 males and 18 females. Common presenting symptoms included head and neck pain (60%), sensory complaints (60%), upper extremity weakness (42%), and gait disturbance (40%). Neurological findings included signs of central cord dysfunction (73%), long-tract motor and/or sensory findings (58%), brainstem signs (38%), cerebellar dysfunction (18%), and increased intracranial pressure (15%). The majority of patients underwent myelography with or without computed tomography of the cervical-medullary junction. Two recent patients had 0.15T MRI scans which helped demonstrate an intramedullary syrinx. Thirty-three patients underwent 47 operative procedures (discounting spinal fusion and CSF shunt revisions). Open surgical management was performed in 32 patients, with CSF shunting along in one patient. Five patients (15%) incurred surgical complications within a six week postoperative period. Follow-up to date, ranges from one month to 11 years. In the 33 surgically treated patients, 18 are improved (55%), 10 are neurologically stable (30%), and five have worsened clinically (15%), including one death. Based on this study it appears that the Chiari II malformation may be more common in adults than previously recognized. Surgical intervention has a favourable outcome in the majority of patients but a significant proportion continue to deteriorate.
Chiari malformations are a group of abnormalities that occur in the back of the head where the brain and spinal cord connect. The Johns Hopkins Chiari Malformation Center provides expert care to both children and adults with all types of Chiari malformation and related conditions like syringomyelia.
As a baby, Adelynn was diagnosed with a Chiari malformation that was interfering with her ability to eat, sleep and breathe. She underwent surgery at Johns Hopkins to correct the problem, and today she is a healthier, happier child.
Some individuals have a condition related to syringomyelia known as hydromyelia, which is characterized by abnormal widening of the central canal of the spinal cord (the small canal running through the center of the spinal cord). These small cavities are filled with cerebrospinal fluid and their significance, if any, is not known. Some physicians use the terms syringomyelia or hydromyelia interchangeably. However, hydromyelia cavities connect to the fourth ventricle (an area in the brain that normally contains cerebrospinal fluid). Hydromyelia may also be present in infants and young children with or without brain abnormalities, such as Chiari malformation type II. The fluid-filled cavities in cases of syringomyelia often do not connect to any other fluid-filled areas or spaces and occur more often in adults than children.
Researchers have determined that some individuals with a Chiari malformation have minimal or no herniation of the cerebellar tonsils through the foramen magnum. These individuals often have syringomyelia despite the lack of cerebellar tonsil herniation. Occipital headaches may also occur. Symptoms in these cases are most likely due to abnormalities in the flow of cerebrospinal fluid at the level of the foramen magnum at the skull base, although there is often no identifiable cause. Individuals with this condition have improved after decompression surgery. The addition of Chiari malformation type 0 as a classification for Chiari malformations is controversial; some physicians believe that, for a diagnosis of a Chiari malformation, tonsillar herniation must be present.
Symptomatic Chiari malformations are most often treated by surgery. There are no specific criteria or objective tests that can be used to determine when to undergo surgery or the best procedures to choose. The procedure that is best may differ for children and adults. The most common surgery is known as posterior fossa decompression. With this procedure, a surgeon creates room by removing small pieces of bone in the back of the skull, thereby enlarging the foramen magnum. This relieves pressure and reduces compression on the brainstem, and may allow the cerebellar tonsils to move back to a more normal position.
Surgical treatment of a Chiari malformation has variable results. One study found that more than 80 percent of adults reported significant improvement in symptoms after surgery. However, response to therapy is highly variable. Symptoms related to a Chiari malformation may respond differently from symptoms related to an associated syringomyelia. Although some individuals experience significant improvement, others may have symptoms that persist including residual pain, muscle weakness, and loss of sensation. In addition, surgery carries risks such as leakage of cerebrospinal fluid or infection.
Syringomyelia associated with a Chiari malformation usually does not require direct treatment. In most cases, syringomyelia improves on its own after surgery to correct a Chiari malformation because the normal flow of cerebrospinal fluid is restored.
Individuals require periodic follow up after surgical treatment for a Chiari malformation. Symptoms may recur after a successful surgery, usually within the first two years. Most likely, this is due to the development of scar tissue or an opening around the duraplasty covering the brain. Children required periodic MRI examinations because of the normal continued growth of the brain and skull.