*Application of Computer-Assisted Surgery System Based on Artificial Intelligence in Pediatric… DOI: http://dx.doi.org/10.5772/intechopen.111509*

liver tumor. Enhanced CT allowed for an approximate analysis of the tumor size and the adjacent relationships (**Figure 3A–D**). 3D imaging based on CT could show the location of the liver, the tumor, and all internal ductal structures in relation to each other in a comprehensive, whole, and simultaneous manner. When vascular involvement was evaluated after 5 cycles of neoadjuvant chemotherapy, it was found that the left hepatic vein cointersected with the middle hepatic vein and merged into the inferior vena cava. The tumor margin was only 0.5117 mm from the cointersection (**Figure 3E–H**). Preoperative simulation of right hemicolectomy showed that the residual liver volume was sufficient. The surgery was performed according to the preoperative plan, and the cointersection and the middle hepatic vein were successfully preserved (**Figure 3I–L**).

**Figure 4** shows another 3-month-old girl with a massive tumor volume (459.1 ml) when her liver-occupying lesion was detected. The tumor was compressing and invading important blood vessels of the liver, and an aspiration biopsy confirmed HB. Neoadjuvant chemotherapy was the only option other than liver transplantation (**Figure 4A** and **B**). The tumor remained unresectable based on the evaluation performed after 4 cycles of neoadjuvant chemotherapy (**Figure 4C** and **D**). The reevaluation after 5 cycles of neoadjuvant chemotherapy showed no significant change in tumor volume, from 35.7 ml to 35.0 ml, and the tumor was still too close to the important blood vessels of the liver and could not be operated on (**Figure 4E** and **F**). The re-evaluation after 6 cycles of neoadjuvant chemotherapy showed that the tumor was slightly reduced in size, from 35.0 ml to 25.9 ml, and the tumor was in contact with blood vessels, so surgical resection was considered (**Figure 4G** and **H**). Intraoperative 3D images assisted the surgery. The operation was successful, the

**Figure 4.** *Computer-assisted resection of middle lobe tumor of the liver.*

tumor was completely removed, and the middle hepatic vein and portal vein were successfully preserved (**Figure 4I–L**).

#### **4.2 Pediatric retroperitoneal tumor**

Retroperitoneal tumors (RTs) are insidious in origin, lack specific clinical manifestations, and have multiple pathological types. Due to their special anatomical location, these tumors are often found to involve large blood vessels and adjacent organs. The incidence of RTs is low, accounting for approximately 0.07%–0.20% of systemic tumors [18]. However, its malignant degree and recurrence rate are high, so complete surgical resection is the most effective treatment and affects the prognosis [19, 20]. Therefore, it is particularly important to accurately evaluate the anatomical relationships of RTs.

At present, the preoperative evaluation of RTs mainly relies on ultrasound, CT, and MRI. Among them, CT is fast, with high resolution and clear images, and can objectively reflect the compression and displacement of tumors with the surrounding organs and large blood vessels, and it has good reference value [21]. However, CT can only provide simple 2D images, and surgeons can generally judge the tumor's size, location, and adjacent relationships by reading consecutive 2D images. However, this lacks objective accuracy and does not facilitate preoperative communication with colleagues and family members. In addition, more importantly, CT images can only show blood vessels along a specific cross-section and cannot fully display the course and wall shape of the curved blood vessels or show large compressed vessels such as the abdominal aorta, inferior vena cava, portal vein, mesenteric arteries, and iliac vessels in detail.

The application and development of digital medical technology overcame the disadvantages of CT. 3D reconstruction of CT images has made it possible to display the relationships of the tumor with surrounding adjacent organs and blood vessels in a three-dimensional, dynamic, and visualized manner. Hisense CAS can also build a 3D model, which can be rotated, scaled, and combined in any way to clearly show the size and shape of the tumor and the anatomical relationships and invasion situation between the tumor and the organs and blood vessels, especially the shape of the vasculature, thus reducing the subjective error of reading the original CT images to assess the size and degree of tumor invasion and making the preoperative assessment more realistic and reliable.

Pediatric RTs are mostly neuroblastic tumors, including neuroblastoma (NB) and ganglioneuroblastoma (GNB), which are malignant tumors, and ganglioneuroma (GN), which is a benign tumor. All three types originate from primitive neural crest cells in the neuroectoderm but are difficult to distinguish and can be mutually transformed [22]. NB is one of the most common malignant solid tumors in children and has no specific symptoms or signs. Its CT manifestations are as follows: mostly lobulated; poorly defined; often with coarse, patchy calcifications within the tumor; infiltrative growth across the midline; and high rate of involvement of the surrounding vital tissues and organs. Pediatric RTs are often found in stages III and IV and enveloping and infiltrating large retroperitoneal vessels, and up to 45% of abdominal neuroblastomas have invasion into the renal pedicle. Often the preoperative differential diagnosis between pediatric RTs and nephroblastoma becomes difficult due to excessive invasion of the kidney. This makes it difficult to resect NB. Despite chemotherapy, there are still quite a number of cases with only biopsy or partial resection, and radical surgery without a tumor at the surgical margin under the microscope is
