Pediatric Minimally Invasive Surgery: Implementation into current surgical practice and impact on neonatal physiology

A growing number of pediatric surgical indications can be treated by minimally invasive surgical techniques. Proponents of minimally invasive surgery claim that there is less surgical trauma, faster recovery and better cosmetic outcomes. The magnification of the operative field and the ability to access and perform surgery in limited anatomical spaces has advantages that are especially appealing to pediatric surgeons.

This thesis discusses several aspects of pediatric minimally invasive surgery. In the first part we describe how minimally invasive surgical treatments in our hospital have evolved since their introduction. Also the institutional learning curve of thoracoscopic esophageal atresia surgery is described. In the second part we studied the effect of the applied pneumoperitoneum or pneumothorax in animal models. We found impaired intestinal anastomotic healing when high pressure pneumoperitoneum (10 mmHg) was applied as compared to open surgery or low pneumoperitoneum pressures (5 mmHg). High-pressure pneumothorax application led to severe impairment of cardiovascular functions, which was accompanied by higher cerebral oxygen extraction, possibly by impaired cerebral perfusion. In the third part of the thesis the effects of minimally invasive surgery on the vascular response, physiology, and cerebral perfusion in neonates and small children is investigated. We evaluated the sublingual vascular response by the application of 8 mmHg pneumoperitoneum during laparoscopic correction of pyloric stenosis in young infants. Elevation of the end tidal carbon dioxide during the pneumoperitoneum was accompanied by an increased sublingual microvascular dilatation, this effect was abolished when the pneumoperitoneum stopped. In a similar group of patients brain oxygenation, recorded by near-infrared spectroscopy, remained stable during the laparoscopic procedure. During esophageal atresia corrections, intrathoracic carbon dioxide insufflation with a maximum pressure of 5 mmHg caused a reversible oxygen saturation drop, hypercarbia, and acidosis, all of which remained within acceptable limits. Blood pressure fluctuations could be avoided by fluid expansion or inotropic support; cerebral oxygenation remained stable during the procedure.

laparoscopic procedures have become an established approach in children and neonates in our pediatric surgical training center. For thoracoscopic esophageal atresia correction there clearly exists an institutional learning curve. Supervision and guidance by senior staff members that have mastered the procedure seems to be a prerequisite for pediatric surgical centers that aim to start introducing this technique. High pressure pneumoperitoneum pressures should be avoided as this can impair intestinal anastomotic healing. In thoracoscopic surgery high pressures pneumothorax of 10 mmHg should be avoided as this can cause severe hemodynamic instability. The laparoscopic procedure for the treatment of pyloric stenosis can be performed under safe physiological conditions. Only a minimal reversible microvascular response was seen, which had no effect on cerebral oxygenation. Esophageal atresia can safely be corrected by thoracoscopy if there is a close collaboration between the anesthesiologists, neonatologists and pediatric surgeons. Furthermore, close monitoring and protocolized management of physiological parameters can result in stable anesthetic conditions with sustained cerebral oxygenation in neonates during prolonged thoracoscopic surgery.