Cerebral aqueduct dilation for hydrocephalus

Congenital malformations of the midbrain aqueduct can lead to obstructive hydrocephalus. Aqueduct septum, stenosis and inflammatory adhesions are the most common causes. An effective way to treat such hydrocephalus is to reconstruct the cerebrospinal fluid circulation pathway. Dandy was the first advocate of midbrain aqueduct expansion, and performed dilatation in 2 patients with dysplasia of the midbrain. Since then Frazer and Leksell have also done this type of surgery. At that time, due to the limitations of the condition, the postoperative mortality was very high, so most scholars used the ventricle-cerebellar medullary shunt (Torkildsen surgery). However, in recent years, cases of catheter augmentation have increased, and satisfactory results have been obtained. Treating diseases: hydrocephalus Indication 1. Conduit tube congenital diaphragm or valve-like obstruction. 2. Inflammatory adhesion of the aqueduct. Preoperative preparation 1. Ventricular angiography or magnetic resonance imaging (MRI) to determine the location of the obstruction of the aqueduct, it is best to show the characteristics of obstruction in order to analyze the nature of obstruction. 2. Preoperative preparation for craniotomy of the posterior cranial fossa. Surgical procedure Incision The median incision of the posterior fossa. 2. Bone window craniotomy The occipital bone window was made according to the method of posterior cranial fossa exploration, and the posterior margin of the occipital bone was removed. 3. Cut the dura mater The "Y" shape cuts the dura mater, or cuts radially, and the dura mater properly stops bleeding. 4. Explore the fourth ventricle Carefully cut the arachnoid membrane of the occipital cistern, separate the cerebellar tonsils on both sides, and expose the median hole. If there is adhesion, gently separate it with a stripper. The bipolar electrocoagulation was used to treat the blood vessels on the surface of the ankle, protect the branches of the posterior cerebellar artery on both sides, cut the lower part of the iliac crest, enter the fourth ventricle, and probe along the central sulcus at the bottom of the ventricle. Gradually approach the opening of the aqueduct and probe the lower end of the aqueduct. Observe the presence or absence of cerebrospinal fluid outflow, and measure the diameter of the aqueduct to determine the direction in which it travels. 5. Expanding the midbrain aqueduct The diameter of the normal adult aqueduct is about 1~2mm and the length is 15~20mm. According to the diameter of the opening of the water conduit, choose a suitable thin and soft catheter or silicone tube. Apply the paraffin oil to the catheter and follow the water conduit. The direction is slowly inserted, and if there is slight resistance, you can move on. Insert about 15mm, attach a 10ml syringe, gently pump, such as entering the third ventricle, you can withdraw the cerebrospinal fluid. Then slowly pull out the catheter, at which time the cerebrospinal fluid flows out of the source of the water conduit, and the expansion is successful. 6. Close the incision The dura mater is tightly sutured, and the muscle, subcutaneous tissue and skin are sutured in layers to prevent cerebrospinal fluid leakage. complication The main complication of aqueduct dilatation is midbrain injury, after the occurrence of patient consciousness disorder, severe long-term coma or death. In order to prevent this complication, the surgical indications must be strictly controlled before surgery to determine the cause and location of the obstruction of the aqueduct. It is estimated that the obstruction of the aqueduct should not be performed in difficult cases. In addition, some authors emphasize that the catheter must be lubricated during surgery, and the catheter can be spread with paraffin oil or other harmless oil to reduce the damage of the midbrain.