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Brock's Operation 3D Medical Animation

00:00-1:13 Intro 1:14-5:12 - History 5:13- 8:15 - Brock's Operation details 8:16- 12:00 - Animated Operation Procedure 12:00- End - Other references Pulmonary Stenosis may exist as a single defect or may be present in combination with other defects such as overriding of the aorta, interarticular or interventricular communications, Patent ductus arteriosus, and the like. The stenosis may be valvular or infundibular, or both. If the stenosis is purely valvular, the outflow tract of the right ventricle is normal; the pulmonary artery may be hypoplastic, normal or dilated. If there is infundibular stenosis, the outflow tract of the right ventricle is interrupted by a ridge of tissue, in effect a defective septum which encroaches upon its lumen and contributes to the formation of a fifth cardiac chamber. This chamber may be so small as to be inappreciable when the ridge of tissue is immediately sub valvular, or it may be quite large when the septum is lower in the ventricle. As in the case of valvular stenosis, the pulmonary artery may be hypoplastic, normal or dilated. Whatever the type of defect, the ultimate effect is the same; blood cannot pass with ease into the pulmonary circuit. One of the biggest problems remaining in the surgical treatment of Fallot's tetralogy concerns the management of right ventricular out flow obstruction in patients with severe hypoplasia of the pulmonary artery and annulus. In 1948, Brock, using a cardio scope of his own design, attempted to visualize the pulmonary valve and relieve pulmonary stenosis by way of the left pulmonary artery. After three unsuccessful attempts he abandoned the technique. Brock concluded that visualization of the pulmonary valve from the pulmonary artery before surgically reliving the stenosis carried too high a risk. He then turned to Doyen's trans-ventricular approach, using a specially designed spade-shaped knife. Subsequently, an expandable metal dilator was added to split the valve leaflets further after passage of the valvulotome. Using this technique of pulmonary valvulotomy, he and others achieved good results with low risk to the patient. SURGICAL STEPS OF BROCK'S OPERATION 1. Median Sternotomy performed to expose the heart 2. Thymus dissection done. 3. Pericardium opened in the midline. 4. Systemic Heparinization done. 5. Purse-string sutures are placed in the ascending aorta for arterial cannulation and either bicaval cannulation or right atrial single cannula. 6. Aorta is cross-clamped, and cold cardioplegic solution is infused (crystalloid or blood cardioplegia). 7. Incise the infundibulum by doing infundibulectomy. 8. Pulmonary annulus and valve should be preserved 9. Right Ventricular Outflow Tract (RVOT) should be sized just to the required size of the Hegar dilator to prevent pulmonary flooding and right ventricle distension due to excessive pulmonary regurgitation 10. RVOT patch should be taut and try to use PTFE (Polytetrafluoroethylene) patch or bovine pericardial patch so that native pericardium is retained for subsequent corrective surgery. 11. A non-distensible RVOT patch also helps that in ensuring the energy of RV contraction is transmitted to the distal pulmonary vascular bed rather than expended in distending a redundant RVOT patch. 12. Right ventricle (RV) pressure should be just sub-systemic and a pulsatile pulmonary artery flow should exist. 13. When performing CPB with a beating heart to improve safety, the root can be kept on continuous suction with head down to prevent air embolism. 14. Cardioplegia can be used at the discretion of the operating surgeon.