Dandy-Walker deformity surgery

Dandy-Walker malformation is one of the causes of hydrocephalus, accounting for 2% to 4% of hydrocephalus. It is first reported by Dandy, Blackfan, Taggart, Walker, etc. It is generally considered to be a developmental malformation before birth. Mainly manifested as the fourth ventricle mesore and lateral hole atresia, the fourth ventricle cyst-like enlargement, the midbrain aqueduct, the third ventricle and the lateral ventricle are also enlarged. Clinical manifestations include increased intracranial pressure, cerebellar ataxia, unstable walking, and low intelligence. Some patients have other malformations of the body. The disease needs to be treated with surgery. At present, there are several surgical methods: 1 simple cystectomy for patients without hydrocephalus; 2 shunt, including lateral ventricular shunt or cyst shunt; 3 lateral ventricle and cyst double shunt About 16% to 92% of patients require such surgery. Many authors believe that simple resection of cysts is prone to recurrence early after surgery; simple lateral ventricle cerebrospinal fluid shunt can not effectively reduce posterior fossa pressure, and may also appear on the cerebellar palsy; and lateral ventricle, cyst-peritoneal double shunt to make posterior fossa cysts and At the same time, the lateral ventricle is decompressed, which is the preferred surgical method for Dandy-Walker malformation. Treatment of diseases: congenital malformations of the brain Indication Dandy-Walker malformation surgery is available for: 1. Dandy-Walker malformation with hydrocephalus. 2. The isolated fourth ventricle with hydrocephalus. Contraindications 1. Intracranial infection has not been controlled. 2. Inflammation or ascites in the abdominal cavity. 3. The protein content of cerebrospinal fluid is too high, exceeding 500mg/L, or there is fresh bleeding. 4. The skin of the head and neck or chest and abdomen is infected. Preoperative preparation 1. Basic anesthesia or general anesthesia, take the supine position, head to the left. 2. Prepare the skin of the head, neck, chest and abdomen. Surgical procedure 1. Head incision: 4 to 5 cm on the right auricle, backward to the outside of the pillow, down to the neck 1 level. 2. The posterior cranial fossa was opened to the underside of the occipital plexus, and the occipital scaly was exposed. The hole was drilled 2.0 cm to the right side of the midline, and the bone window was enlarged to a diameter of about 1.5 cm. Open the dura mater, in the cerebellar cortex without blood vessels, guide the shunt with a guide needle, puncture from the lateral side to the contralateral external auditory canal, insert the fourth ventricle or cyst, remove the guide pin and then re-inject the tube into 2 ~3cm. After the cerebrospinal fluid outflows, the drainage tube is fixed on the dura mater or periosteum, a bevel is bitten in the bone hole, and the fourth ventricle tube is led to the right mastoid, and a shunt pump is installed. 3. Lateral ventricle shunt with VP. 4. Separate the subcutaneous tunnel and install the abdominal catheter with VP. Two independent drainage tubes enter from the same subcutaneous tunnel. Note that the two tubes cannot be entangled, and multiple thin tubes can be fixed at the open ends of the abdominal tube. 5. It is also possible to use a "Y"-shaped connecting tube to connect the lateral ventricle and the fourth ventricle drainage tube to the same diverter valve and share one abdominal tube. To prevent cerebrospinal fluid from flowing back through the "Y" tube, a one-way valve can be installed at the proximal end of the two tubes. complication 1. Symptoms of digestive tract: Infants may experience abdominal distension, abdominal pain, loss of appetite or nausea and vomiting after surgery. In addition to surgical disturbances, the main cause is the stimulation of the peritoneum by the cerebrospinal fluid, which usually disappears in a week or so. 2. Infection: Due to the long subcutaneous route of the shunt catheter, there are many opportunities for local infection. After infection, it can cause intracranial infections such as ventriculitis and meningitis. It can also cause peritonitis, underarm abscess or abdominal abscess; local subcutaneous infection occurs subcutaneously. Cellulitis or subcutaneous abscess. Therefore, it is necessary to strictly disinfect during surgery. It is extremely important to apply antibiotics before and after surgery. 3. Divert catheter obstruction. The reasons for this are: 1 the valve is blocked, mostly due to the excessive protein in the ventricle, and the accumulation of sediment in the membrane valve. Therefore, when the ventricular fluid protein exceeds 1000 mg/L, the valve is not used, and only the slit conduit is used for shunting. The four slit openings at the end of the abdominal catheter were cut with a knife and lengthened to 1 cm to facilitate shunting. After the protein content of the cerebral ventricle is decreased, the valve is diverted by a regular valve. 2 The peritoneal tube is twisted, and the end of the tube is covered by the omentum or forms a pseudocyst (containing cerebrospinal fluid), which can cause the shunt to fail. After the discovery, it should be treated in time, and the catheter should be repositioned to other parts of the abdominal cavity, or other shunts should be used instead. 4. Abdominal catheter prolapse: The most common is that the catheter is released from the abdominal incision, and some or even all of it is removed from the abdominal cavity and exposed to the skin. This is because the subcutaneous tunnel is too shallow, the catheter is rubbed and pressed for a long time with the epidermis, causing skin necrosis, or secondary infection, the suture is detached, and the catheter is taken out of the abdominal wall. When this happens, it can be handled according to the condition of the incision. If the incision is not infected, the granulation is relatively fresh, and the catheter is partially removed. After 3 days of wet application with the antibiotic solution, the catheter is redirected and placed in the abdominal cavity. The split incision is sutured in full layer, and some patients can be cured; if the incision is obviously infected, it should be immediately Replace the new abdominal tube. 5. Abdominal organ damage: Some end of the abdominal catheter is hard, such as the stainless steel spring on the wall of the Raimondi catheter, which may cause intestinal perforation, transverse perforation and vaginal perforation due to surgical trauma or long-term mechanical friction at the end of the catheter. Nowadays, there is a new type of catheter, which has no metal. It is mainly made of silicone rubber. The tube is relatively strong, and it is not easy to cause mechanical collapse or distortion of the tube wall, and the chance of damage to the internal organs is greatly reduced.

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