Laparoscopic Liver Surgery Guided by Virtual Real-time CT-Guided Volume Navigation

3-D reconstruction in liver surgery: a systematic review

BACKGROUND

Three-dimensional reconstruction of the liver offers several advantages to the surgeon before and during liver resection. This review discusses the factors behind the use of liver 3-D reconstruction.

METHODS

Systematic electronic search, according to PRISMA criteria, was performed. A literature search of scientific papers was performed until October 2023. Articles were chosen based on reference to 3-D liver reconstruction and their use in liver surgery. GRADE methodology and the modified Newcastle-Ottawa scale were used to assess the quality of the studies.

RESULTS

The research included 47 articles and 7724 patients were analyzed. Preoperative planning was performed with 3-D liver reconstruction in the 87.2% of the studies. Most of preoperative 3-D liver reconstructions were performed in the planning of complex or major hepatectomies. Complex hepatectomies were performed in 64.3% patients. The 55.3% of the studies reported an improved navigation and accuracy during liver resection. Four studies (8.6%) on living donor liver transplant (LDLT) concluded that 3-D liver reconstruction is useful for graft selection and vascular preservation. Nine papers (19.1%) reported an accurate measurement of future liver remnant.

CONCLUSION

Liver 3-D reconstruction helps surgeons in the planning of liver surgery, especially in liver graft and complex liver resections, increasing the accuracy of the surgical resection.

Enhanced Recognition Confidence of Millimeter-Sized Intrahepatic Targets by Real-Time Virtual Sonography

OBJECTIVES

Real-time virtual sonography (RVS) is an artificial-intelligence-assisted ultrasonographic navigation system that displays synchronized preoperative computed tomography (CT) images corresponding to real-time intraoperative ultrasonograms (IOUS). This study aimed to investigate whether RVS can enhance IOUS identification of small intrahepatic targets found in preoperative CT.

METHODS

Patients with small intrahepatic targets detected by preoperative thin-slice dynamic CT before liver resection were included. The targets included millimeter-sized liver tumors or a third-order or more distal portal branch and were marked on CT images using 3D simulation software. After laparotomy, the targets were searched using fundamental IOUS, and participating liver surgeons subjectively scored the target identifying confidence on a scale of 1-5 (5 points for detection with the highest confidence and one point for undetectable). Then, the search procedure was repeated using the RVS, and the scores were compared.

RESULTS

Totally, 55 patients with 117 small targets were investigated. The median target size was 6.0 mm, and the median registration time was 3.6 seconds. The target identification confidence score significantly increased from 2.78 to 4.52 points after using RVS. Seventeen targets (14.5%) were undetectable in fundamental IOUS, and 14 of them were identified by RVS. The detectability of small liver tumors (2-5 points of identification confidence) by IOUS was 81.1 and 96.7% by RVS.

CONCLUSION

RVS enhanced surgeons' confidence in identifying millimeter-sized intrahepatic targets found in preoperative CT.

The effect of operator's experience on mechanical thrombectomy outcomes: A systematic review

BACKGROUND

Mechanical thrombectomy (MT) has become the standard of care for stroke patients. The majority of the clinical trials and publications analyzing the outcomes related to the procedures report interventional performance by experienced practitioners. However, few of them individualize their preliminary metrics according to the operator's experience.

OBJECTIVE

To summarize the literature and report safety and efficacy outcomes following MT procedures and correlate them with the operator's experience. Primary outcomes were successful recanalization, defined as modified thrombolysis in cerebral infarction greater or equal to 2b or 3, duration of the procedure measured in minutes, and serious adverse event.

METHODS

This systematic review was performed according to the PRISMA guidelines. The PubMed, Embase, and Cochrane databases were utilized.

RESULTS

There were six studies comprising 9348 patients (mean age 69.8 years; 51.2% males), and 9361 MT procedures were included. Each publication used for this review used a different experience definition to report their data. Higher interventionists' experience demonstrated a positive relationship with the possibility of successful recanalization and an inverse relationship with the duration needed for the operation in almost all of the included studies. As for the complications, none of the authors reported a statistically significant risk reduction of an adverse event, except Olthuis et al. correlating increasing training with lower odds of stroke progression.

CONCLUSIONS

A higher experience level is associated with better recanalization rates and shorter procedural duration in MT operations. Further studies are warranted to define the minimum required level of experience for operational autonomy.

Development of an innovative surgical navigation system for sacrospinous fixation in pelvic surgery

STUDY OBJECTIVE

To validate the use of an innovative navigation method for sacrospinous fixation in surgery-like conditions as a new teaching tool and surgical method.

DESIGN

2-month-experiment prospective pilot study between July and August 2021.

SETTING

Biomechanics laboratory academic research.

POPULATION

29 participants: 9 gynecological surgeons and 20 participants with no medical background.

MEASUREMENT AND MAIN RESULTS

The experiment was composed of two training phases dedicated to improve the hand-eye coordination and suture skills on a training mock-up, and of a suturing phase on a pelvic mock-up designed to recreate the surgery-like conditions of a sacrospinous fixation. The surgeons provided qualitative feedback on the bio-accuracy of the mock-ups and evaluated the ease-of-use of the navigation software. Non-surgeons were included to assess the progression of the suture performance between two experiments performed one week apart (Session 1 & 2). The main objective for participants was to reach a virtual target and to stitch sacrospinous ligaments. For Session 1, an overall comfort score of 7.2/10 was attributed to the tool; 14 (42%) surgeon suture attempts and 63 (65%) non-surgeon suture attempts were accurate (i.e. below the 5-mm threshold). 22 (67%) surgeon suture attempts and 28 (34%) non-surgeon suture attempts were fast (i.e. in the first two quantiles of the duration dataset). An improvement of the non-surgeon performance was observed between the two sessions in terms of duration (Session 1: 46±20 sec; Session 2: 37±18 sec; p=0.047) and distance (Session 1: 3.8±1.3 mm; Session 2: 3.2±1.4 mm; p=10^-5) for the last suturing exercise.

CONCLUSION

This new motion-capture-based navigation method for sacrospinous fixation tested under surgery-like conditions seemed to be accurate and effective. The next step will be to design a pelvis model more adapted to the constraints of a sacrospinous fixation and to validate the benefits of this method compared to current techniques.

Clinical use of augmented reality, mixed reality, three-dimensional-navigation and artificial intelligence in liver surgery

A precise knowledge of intra-parenchymal vascular and biliary architecture and the location of lesions in relation to the complex anatomy is indispensable to perform liver surgery. Therefore, virtual three-dimensional (3D)-reconstruction models from computed tomography/magnetic resonance imaging scans of the liver might be helpful for visualization. Augmented reality, mixed reality and 3D-navigation could transfer such 3D-image data directly into the operation theater to support the surgeon. This review examines the literature about the clinical and intraoperative use of these image guidance techniques in liver surgery and provides the reader with the opportunity to learn about these techniques. Augmented reality and mixed reality have been shown to be feasible for the use in open and minimally invasive liver surgery. 3D-navigation facilitated targeting of intraparenchymal lesions. The existing data is limited to small cohorts and description about technical details e.g., accordance between the virtual 3D-model and the real liver anatomy. Randomized controlled trials regarding clinical data or oncological outcome are not available. Up to now there is no intraoperative application of artificial intelligence in liver surgery. The usability of all these sophisticated image guidance tools has still not reached the grade of immersion which would be necessary for a widespread use in the daily surgical routine. Although there are many challenges, augmented reality, mixed reality, 3D-navigation and artificial intelligence are emerging fields in hepato-biliary surgery.

CycleGAN for interpretable online EMT compensation

PURPOSE

Electromagnetic tracking (EMT) can partially replace X-ray guidance in minimally invasive procedures, reducing radiation in the OR. However, in this hybrid setting, EMT is disturbed by metallic distortion caused by the X-ray device. We plan to make hybrid navigation clinical reality to reduce radiation exposure for patients and surgeons, by compensating EMT error.

METHODS

Our online compensation strategy exploits cycle-consistent generative adversarial neural networks (CycleGAN). Positions are translated from various bedside environments to their bench equivalents, by adjusting their z-component. Domain-translated points are fine-tuned on the x-y plane to reduce error in the bench domain. We evaluate our compensation approach in a phantom experiment.

RESULTS

Since the domain-translation approach maps distorted points to their laboratory equivalents, predictions are consistent among different C-arm environments. Error is successfully reduced in all evaluation environments. Our qualitative phantom experiment demonstrates that our approach generalizes well to an unseen C-arm environment.

CONCLUSION

Adversarial, cycle-consistent training is an explicable, consistent and thus interpretable approach for online error compensation. Qualitative assessment of EMT error compensation gives a glimpse to the potential of our method for rotational error compensation.