Augmented-Reality Imaging During Surgery for Bile-Duct Gallstones Reduces Residual Stones

NEW YORK (Reuters Health) – Employment of an augmented reality-assisted navigation system (AR-ANS) during hepatectomy for hepatolithiasisiIncreases operative time but reduces the risk of residual and recurrent stones, a retrospective study suggests.

Dr. Xiwen Wu and colleagues from Zhujiang Hospital of Southern Medical University in China compared outcomes of 31 patients who underwent AR-ANS-assisted hepatectomy for hepatolithiasis and 46 patients who underwent conventional laparoscopic hepatectomy. The two groups were similar in age, gender, liver function tests, and type of hepatectomy.

All patients underwent preoperative three-dimensional imaging. Indocyanine green (ICG) was intravenously injected from the periphery 24-72 hours before surgery at a dose of 0.25-0.5mg/kg for the intraoperative display of the atrophic liver segment, extrahepatic bile duct, and bilioenteric anastomosis. After liver resection, the distal common bile duct was temporarily blocked and ICG was injected through the cystic duct or cross-section bile duct to detect and deal with any bile leakage. Choledochostomy was routinely used intraoperatively for the remaining stones and the possible presence of bile duct lesions or tumors.

In the AR-ANS group, 3D visualization models were superimposed onto 3D laparoscopic surgery scenes and fluorescence images in real-time to form augmented reality effects and achieve real-time fusion of multimode images.

With AR-ANS, operative time was significantly longer (367 min, vs 271 min without AR-ANS, P<0.001), but significantly less blood was lost (112 ml vs 207 ml; p <.001). Fewer AR-ANS patients needed blood transfusions, but the difference was not statistically significant (12.9% vs 17.4%, p=ns).

Post op ALT was significantly lower in the AR-ANS group than in the control group (46.37 U/L vs 79.38 U/L, respectively; p=0.001), as was AST (5.13 U/L vs. 45.52 U/L; p=0.002). There was no difference in complication rates between the groups.

The immediate postoperative stone residual rate, defined as intrahepatic bile duct stones within three months after liver resection, was significantly lower in the AR-ANS group (19.4% vs 41.3%, P=0.044). The AR-ANS group also had lower rates of stone recurrence, defined as stone presence or onset of cholangitis after more than 6 months (12.5% vs 30.4%, P=0.046), and stone extraction of T tube sinus tract (15%vs 34.8%, P =0.036).

Two patients with residual stones in the AR-ANS group and nine of 12 in the control group were treated successfully with postoperative cholangioscopy from the T-tube tract, resulting in a 100% success rate in the AR-ANS group and 75% in the control group.

The authors note that residual hepatolithiasis is the most intractable problem after surgery and in this study, the AR-ANS group had a higher clearance rate. They further note that hepatolithiasis “is generally accompanied by severe hilum rotation or even ‘frozen’ hilum occlusion, resulting in unclear anatomy…and easy injury of the hepatic artery or portal vein.”

“Especially in the dissection of porta hepatis and resection of the liver parenchyma,” they wrote, AR-ANS “can realize the real-time positioning and navigation of vascular structures, allowing surgeons to predict the important blood vessels to be encountered in advance so as to perform targeted protection or ligation, which markedly improves the safety of the operation.”

“These results indicate that augmented reality-guided hepatectomy is a feasible and safe method for the treatment of hepatolithiasis, which has the value of clinical promotion,” the researchers concluded.

SOURCE: Journal of the American College of Surgeons, online June 6, 2022.

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