The Chiari malformation consists of a downward displacement of the caudal portion of the cerebellum and, sometimes, of the brain stem, which are both located below the foramen magnum.
There are two fundamental types of malformation:
1. Type 1 (adult) consisting of a simple descent of the cerebellar tonsils
2. Type 2 (infantile) in which there is a descent of the entire lower cerebellum and brainstem.
When is the intervention indicated?
When this descent of the cerebellar tonsils is symptomatic, that is, when they produce symptoms due to the compression of the brainstem, or because of the difficulty in the passage of cerebrospinal fluid (CSF). The most frequent symptom that occurs in the Chiari malformation is the headache while performing any effort (coughing, sneezing, defecating if there is constipation, etc). Other less frequent symptoms are loss of sensitivity or strength of a limb (either upper or lower), difficulty swallowing fluids, dysphonia, etc. In symptomless cases and when it is only a casual finding on an MRI requested by any other cause, no type of surgical intervention is suggested.
What is the operation about?
It consists basically in the opening of a window through the back of the skull and the blade of the highest cervical vertebra that can be enlarged even to the next vertebra. Subsequently the cerebellum is released from any adhesions that are observed, and it is expanded with a dura mater plasty to the existing space (the space where the cerebellum is harboured gets enlarged).
What are the risks, complications and possible sequelae?
The most frequent risk or complication is the loss of cerebrospinal fluid from the surgical wound, also called CSF fistula. Wound infection or intracerebral pus pockets (rarer) may also occur. Exceptionally, lesions from manipulation of exposed structures, vascular lesions, rebleeding with symptoms of loss of consciousness, loss of strength or sensation in four limbs, alterations of balance and alterations in respiratory and heart functions may arise. Hydrocephalus. Venous thrombosis.
Postoperative – Chiari malformation
After the intervention you will enter an Intensive Care Unit for at least 24 hours. This operation can entail very serious vital risks, although they are very infrequent, so it is advisable that you are under strict surveillance during the first hours.
After the first 24 hours in the ICU, if there are no complications, you will be admitted to an inpatient ward. The next day you will begin to sit up in bed and start oral tolerance. The use of a soft collar is common in the first few days as dissection of the posterior cervical musculature is usually painful, and the use of a neck collar and painkillers usually relieves postoperative pain. If the wound is dry (i e, there is no leakage of cerebrospinal fluid through the wound) you will get out of bed after 24-48 hours and begin to walk around the room, ideally in the company of a family member at the beginning. Hospital discharge comes usually after 3-6 days depending on each case and the recovery rate of each patient.
Once at home, consider that you will continue the period of hospitalisation for at least one more week. Take the medication exactly as prescribed by your surgeon. If you are receiving any other treatment for any other disease, you should continue to do so unless you are told otherwise. The surgical wound should be kept clean and dry. You can shower, with assistance, and then dry well with a sterile pad or gauze, brush the wound with povidone-iodine (PVP-I, Betadine) and finally cover the wound with sterile dressing. Skin sutures should be removed after seven days of surgery. In case of reoperation, wait at least 14 days. During the first week you should alternate periods of walking, sitting and resting in bed inside your home. Do not leave home until sutures are removed. From the second week on, walk for brief periods of time (15 min.) every day, progressively increasing the distances. After 4 weeks you should go to the Outpatients unit for a review.