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ARNOLD-CHIARI MALFORMATION TYPE 1: SURGICAL TREATMENT

Patient education is a powerful weapon in our battle against Chiari and syringomyelia. An informed patient is able to intelligently select a doctor, understand the problems and choices that must be made.

Dr. Milhorat has directed in New York, a team of neurosurgeons who developed the greatest experience in the world on Chiari malformation and syringomyelia.

The experience of Dr. Milhorat beginning in 1991, in 1993 he founded The Chiari Center in Brooklyn, in 2003. The center changes name and location, thus was born the The Chiari Institute in Northern Boulevard. Since 2003 we were treated more than 5,000 patients coming from 50 states and 40 nations.

The indications for surgical treatment of patients with Chiari malformation 1, formulated since the '90s by the team of Dr. Milhorat are today, with some adjustments, shared by most neurosurgeons Americans.

Patients with severe framework of tonsillar herniation but asymptomatic, without syringomyelia, not working but are followed over time. There are indications for prophylactic. This attitude is based on the data of natural history in the adult asymptomatic 65% does not deteriorate, 35% may deteriorate and these ¼ deteriorates for a cervical trauma. 

The signs of the Chiari Institute of New York for surgery decompression of the posterior fossa are divided into:

 

SURGERY IN AN EMERGENCY

- Patients with acute neurological deficit and causing paralysis and inability to swallow, progressive or acute. Such patients are rare and the indication emerging has a frequency of one application per year to The Chiari Institute in New York.

 

SURGERY IN EMERGENCY deferrable (within 6 months)

- Patients with syringomyelia central diameter> 75% of the diameter of the spinal cord;

- Patients with a rapid increase of syringomyelia in two consecutive MRIs;

- Patients with syringomyelic cavity eccentric.

In these cases the indication is to undergo surgery within six months. The patient can refuse, but you have to make it clear that it is not the best choice for possible occurrence of bone marrow damage with consideration clinical deterioration that may be permanent.

 

SURGERY SCHEDULED

- Patients with significantly impaired quality of life objectified by use of clinical scales such as SF36 or Karnofsky;

- Patients with debilitating clinical symptoms;

- Patients in whom there was a failure of conservative treatment.

Patients with mild symptoms are not candidates for surgery as not to operate on patients with moderate or severe symptoms but that answer to conservative treatment.

In this case the choice is the patient, there is no difference in prognosis. The patient is choosing conservative treatment or surgery is not in danger of death and not likely to go in a wheelchair for the appearance of severe neurological signs.

 

The posterior fossa decompression surgery is rarely a cure. Care and something completely eradicated the anatomical alteration and related clinical aspect of the disease. Surgical decompression is designed to increase the space of the posterior cranial fossa in order to decompress the brain structures contained therein and normalize the circulation of cerebrospinal fluid.

 

Surgical intervention, however, more that a cure is a treatment. The posterior fossa decompression is used to lighten the symptom picture, but does not cure the basic malformation.

 

In most cases, even when surgery is satisfactory, life is no longer the same as before the onset of symptoms.

 

Patient with young age, with short medical history, neurological examination normal, use short or no use of narcotics has a better prognosis.

 

If the headache is not classical and the anatomy is not the typical success rate and less than 85%. Some symptoms do not react the same way to surgery, the headache is almost guaranteed that disappears, for other symptoms such as imbalance and chronic fatigue syndrome will have 50-60% success.

 

 The goals of surgical decompression of the posterior fossa in Chiari 1 are:

 

1) Remove the obstacle to the flow of CSF;

 

2) Remove the mass effects of the cerebellar tonsils;

 

3) Remove the neurovascular compression.

 

To achieve the above objectives surgery involves decompression of the posterior fossa.

At present there is no national or international standards on the type of surgical decompression (standard of care), but there is only a spectrum of surgical procedures that all neurosurgeons know.

 

According to the maneuvers that can be used they differ three types of surgical decompression of the posterior fossa:

 

- MINI-INVASIVE SURGERY with the only bony decompression by removal of the occipital bone and the posterior arch of C1 vertebra, some add a small incision of the dura mater.

 

- SURGERY INTERMEDIATE with opening of the dura mater, opening dell'aracnoide and release of the tonsils and packaging plastic dural.

 

- INVASIVE SURGERY in which in addition to the maneuvers of the intermediate surgery there is also a manipulation of the tonsils which are coerced to reduce their volume.

 

No technical procedure is inadequate, no works 100%.

The incidence of complications increases with the more invasive surgeries while effective supervision anatomy is less with less invasive approaches. It 'still plausible start with the less invasive surgery and then, if it is not effective, then proceed with the more invasive surgery.

 

The percentage of success, in the absence of co-morbidity, is of 85%. Failure in 15%, even without complications, for the lack of recognition of associated diseases, in some cases there may be factors associated with that maybe now they are not understood.

 

The most frequent complication is the pseudomeningoceles and is related to INVASIVE SURGERY or INTERMEDIATE (not present in the minimally invasive surgery that does not require the opening of 'arachnoid, meninges in which it circulates the cerebrospinal fluid). In the US it is inversely proportional to the experience of the surgeon. The experienced surgeons in the US are those that operate more than 20 cases per year and these have pseudomeningociele percentages that vary between 3-8%, at The Chiari Institute from 2003 is 0.3%.

11/14/2016 08:11 am