The safe establishment of pneumoperitoneum is a critical step in all laparoscopic surgeries. A closed pneumoperitoneum is usually obtained by inserting a Veress needle into the peritoneal cavity. However, there is no definite measure to visually confirm the position of the Veress needle tip inside the peritoneal cavity. This study aimed to describe a method of real-time visual detection of peritoneal placement of the Veress needle using an incorporated optical coherence tomography (OCT) probe in a porcine model. A 14-gauge Veress needle was incorporated with a miniature fiber probe to puncture the piglet's abdominal wall into the peritoneal cavity. A total of 80 peritoneal punctures were attempted in four piglets. For each puncture, continuous two-dimensional OCT images of the abdominal wall were acquired for real-time visual detection of the needle placement into the peritoneal cavity. Characteristic OCT image patterns could be observed during the puncturing process, especially a deep V-shaped concave pattern before the peritoneum puncture, which was a crucial feature. A statistical difference in the OCT signal standard deviation value also indicated the differentiability of images between the peritoneum and extra-peritoneal tissue layers. A success rate of 97.5% could be achieved with the guidance of the OCT images. OCT images translate the blind closed technique of peritoneal access into a visualized procedure, thus improving peritoneal access safety.
Keywords: Veress needle; laparoscopy; optical coherence tomography; peritoneal cavity.