Enhanced Surgical Imaging: Laparoscopic Vessel Identification and Assessment of Tissue Oxygenation

Abstract

Inherent to minimally invasive procedures are loss of tactile feedback and loss of three-dimensional assessment. Tasks such as vessel identification and dissection are not trivial for the inexperienced laparoscopic surgeon. Advanced surgical imaging, such as 3-charge-coupled device (3-CCD) image enhancement, can be used to assist with these more challenging tasks and, in addition, offers a method to noninvasively monitor tissue oxygenation during operations. In this study, 3-CCD image enhancement is used for identification of vessels in 25 laparoscopic donor and partial nephrectomy patients. The algorithm is then applied to two laparoscopic nephrectomy patients involving multiple renal arteries. We also use the 3-CCD camera to qualitatively monitor renal parenchymal oxygenation during 10 laparoscopic donor nephrectomies (LDNs). The mean region of interest (ROI) intensity values obtained for the renal artery and vein (68.40 +/- 8.44 and 45.96 +/- 8.65, respectively) are used to calculate a threshold intensity value (59.00) that allows for objective vessel differentiation. In addition, we examined the renal parenchyma during LDNs. Mean ROI intensity values were calculated for the renal parenchyma at two distinct time points: before vessel stapling (nonischemic) and just before extraction from the abdomen (ischemic). The nonischemic mean ROI intensity values are statistically different from the ischemic mean ROI intensity values (p < 0.05), even with short ischemia times. We have developed a technique, 3-CCD image enhancement, for identification of vasculature and monitoring of parenchymal oxygenation. This technique requires no additional laparoscopic operating room equipment and has real-time video capability.