Intraoperative real-time tissue elastography during laparoscopic hepatectomy

A Minimally Invasive Robotic Tissue Palpation Device

OBJECTIVE

Robot-assisted minimally invasive surgery remains limited by the absence of haptic feedback, which surgeons routinely rely on to assess tissue stiffness. This limitation hinders surgeons' ability to identify and treat abnormal tissues, such as tumors, during robotic surgery.

METHODS

To address this challenge, we developed a robotic tissue palpation device capable of rapidly and non-invasively quantifying the stiffness of soft tissues, allowing surgeons to make objective and data-driven decisions during minimally invasive procedures. We evaluated the effectiveness of our device by measuring the stiffness of phantoms as well as lung, heart, liver, and skin tissues obtained from both rats and swine.

RESULTS

Results demonstrated that our device can accurately determine tissue stiffness and identify tumor mimics. Specifically, in swine lung, we determined elastic modulus (E) values of 9.1 ± 2.3, 16.8 ± 1.8, and 26.0 ± 3.6 kPa under different internal pressure of the lungs (PIP) of 2, 25, and 45 cmH2O, respectively. Using our device, we successfully located a 2-cm tumor mimic embedded at a depth of 5 mm in the lung subpleural region. Additionally, we measured E values of 33.0 ± 5.4, 19.2 ± 2.2, 33.5 ± 8.2, and 22.6 ± 6.0 kPa for swine heart, liver, abdominal skin, and muscle, respectively, which closely matched existing literature data.

CONCLUSION/SIGNIFICANCE

Results suggest that our robotic palpation device can be utilized during surgery, either as a stand-alone or additional tool integrated into existing robotic surgical systems, to enhance treatment outcomes by enabling accurate intraoperative identification of abnormal tissue.

The Clinical Value of Multimodal Ultrasound for the Differential Diagnosis of Hepatocellular Carcinoma from Other Liver Tumors in Relation to Histopathology

Recent advances in the field of ultrasonography offer promising tools for the evaluation of liver tumors. We aim to assess the value of multimodal ultrasound in differentiating hepatocellular carcinomas (HCCs) from other liver lesions. We prospectively included 66 patients with 72 liver tumors. The histological analysis was the reference standard for the diagnosis of malignant liver lesions, and partially for benign tumors. All liver lesions were assessed by multiparametric ultrasound: standard ultrasound, contrast-enhanced ultrasound (CEUS), the point shear wave elastography (pSWE) using shear wave measurement (SWM) method and real-time tissue elastography (RTE). To diagnose HCCs, CEUS achieved a sensitivity, specificity, accuracy and positive predictive value (PPV) of 69.05%, 92.86%, 78.57% and 93.55%, respectively. The mean shear-wave velocity (Vs) value in HCCs was 1.59 ± 0.29 m/s, which was lower than non-HCC malignancies (p < 0.05). Using a cut-off value of 1.58 m/s, SWM achieved a sensitivity of 54.76%, and 82.35% specificity, for differentiating HCCs from other malignant lesions. The combination of SWM and CEUS showed higher sensitivity (79.55%) compared with each technique alone, while maintaining a high specificity (89.29%). In RTE, most HCCs (61.53%) had a mosaic pattern with dominant blue areas corresponding to type "c" elasticity. Elasticity type "c" was 70.59% predictive for HCCs. In conclusion, combining B-mode ultrasound, CEUS, pSWE and RTE can provide complementary diagnostic information and potentially decrease the requirements for other imaging modalities.

Real-Time Wireless Tumor Tracking in Navigated Liver Resections: An Ex Vivo Feasibility Study

BACKGROUND

Surgical navigation systems generally require intraoperative steps, such as intraoperative imaging and registration, to link the system to the patient anatomy. Because this hampers surgical workflow, we developed a plug-and-play wireless navigation system that does not require any intraoperative steps. In this ex vivo study on human hepatectomy specimens, the feasibility was assessed of using this navigation system to accurately resect a planned volume with small margins to the lesion.

METHODS

For ten hepatectomy specimens, a planning CT was acquired in which a virtual spherical lesion with 5 mm margin was delineated, inside the healthy parenchyma. Using two implanted trackers, the real-time position of this planned resection volume was visualized on a screen, relative to the used tracked pointer. Experienced liver surgeons were asked to accurately resect the nonpalpable planned volume, fully relying on the navigation screen. Resected and planned volumes were compared using CT.

RESULTS

The surgeons resected the planned volume while cutting along its border with a mean accuracy of - 0.1 ± 2.4 mm and resected 98 ± 12% of the planned volume. Nine out of ten resections were radical and one case showed a cut of 0.8 mm into the lesion. The sessions took approximately 10 min each, and no considerable technical issues were encountered.

CONCLUSIONS

This ex vivo liver study showed that it is feasible to accurately resect virtual hepatic lesions with small planned margins using our novel navigation system, which is promising for clinical applications where nonpalpable hepatic metastases have to be resected with small resection margins.

Postoperative Outcomes After Laparoscopic Liver Resections in Low and High-Volume Centers: A Multicentric Case-Matched Comparative Study

BACKGROUND

Laparoscopic liver resection (LLR) is the gold standard for liver resections. Despite its feasibility and safety in high-volume centers (HVC), its performance is controversial in low-volume centers (LVCs). We aimed to evaluate the results of LLR performed in LVC.

METHODS

Patients who underwent LLR between 2013 and 2019 in three LVCs were compared after case-matching with those in an HVC using the Institut Mutualiste Montsouris LLR Difficulty Score (IMMLDS).

RESULTS

Seventy-six patients treated in three LVCs were matched to 152 in HVCs for age, body mass index, and resection type. The incidence of LLR significantly increased in LVCs over time (2013-2016 vs. 2017-2019) (21.2% vs. 39.3%; p = 0.002 and) while abdominal drainage rate decreased (77.4% vs. 51.1%; p = 0.003). In IMMLDS group I (60 vs. 120 patients), higher Pringle maneuver (43.3% vs. 2.5%; p < 0.0001), median blood loss (175 ml vs. 50 ml; p < 0.0001), abdominal drainage (58.3% vs. 6.6%; p < 0.0001), and conversion rate (8.3% vs. 1.6%, p = 0.04) were observed in LVCs. The overall postoperative morbidity was comparable (Clavien I-II: p = 0.54; Clavien > II: p = 0.71). In IMMLDS groups II-III, Pringle maneuver (56.5% vs. 3.1%; p < 0.0001), blood loss (350 ml vs. 175 ml; p = 0.02), and abdominal drainage (75% vs. 28.3%; p = 0.004) were different; however, postoperative morbidity was not. The surgical difficulty notwithstanding, length of stay (group I: p = 0.13; group II-III: p = 0.93) and R0 surgical margin (group I: p = 0.3; group II-III p = 0.39) were not different between LVCs and HVCs.

CONCLUSIONS

LLR performed at an LVC can be feasible and safe with acceptable morbidity.