Laparoscopic Parenchyma-sparing Liver Resection for Colorectal Metastases

Laparoscopic and Open Liver Resections for Colorectal Cancer Liver Metastasis in the Ukrainian State Center

Background Minimally invasive liver resections for metastatic colorectal cancer have been increasingly performed all over the world with promising results. We planned the current study to review our experience on this matter and compare short- and long-term outcomes of laparoscopic liver resection (LLR) and open liver resection (OLR) in patients with colorectal cancer liver metastasis (CRLM). Materials and methods This is a single-center retrospective analysis of patients with CRLM who underwent laparoscopic (n=86) and open (n=96) surgical treatment for metastatic liver lesions between March 2016 and November 2022. Tumor characteristics, intra- and postoperative results, overall survival (OS), and disease-free survival (DFS) were analyzed and compared. Results LLR was associated with significantly shorter surgery duration (180 minutes versus 295 minutes, p=0.03). There was no significant difference in blood loss between the two groups (100 mL versus 350 mL, p=0.061). Additionally, the laparoscopic approach was associated with significantly shorter hospital stays (6 days versus 9 days, p=0.004). The rate of major complications (Clavien-Dindo classification ≥ 3) was lower in the LLR group (5.8% versus 16.6%, p=0.037). There was no mortality in the LLR group, and in the OLR group, one lethal case was induced by mesenteric thrombosis on the fifth postoperative day. We did not find a statistically significant difference in the OS rate between the two groups at one, three, and five years: 97.3%, 74.7%, and 43.4%, respectively, in the OLR group and 95.1%, 70.3%, and 49.5%, respectively, in the LLR group (p=0.53). DFS at one, three, and five years were 88.7%, 52.3%, and 25.5%, respectively, in the LLR group and 71.9%, 53.1%, and 19.3%, respectively, in the OLR group (p=0.66). Conclusions This study showed that laparoscopic liver surgery is a safe and effective method of CRLM treatment in our center. LLR was associated with a decrease in major morbidity, shorter surgery duration, and reduced postoperative hospital stay. Minimally invasive liver resections showed similar oncological outcomes to the open approach in terms of overall and disease-free survival.

Multiple Laparoscopic Liver Resection for Colorectal Liver Metastases

Over the past decades, liver cancer's minimally invasive approach has primarily become as a new standard of oncological care. Colorectal liver metastases (CRLM) are one of the most developed indications of laparoscopic liver resection (LLR). CRLM resection is still the best treatment known in terms of survival. As multiple CRLM are found in up to 80% of cases at diagnosis (Manfredi S. and al, Annals of Surgery 2006), a lot of possible technical management approaches are described. With the development of the parenchymal-sparing strategy, multiple concomitant laparoscopic liver resections (LLR) are gaining acceptance. However, no recommendation is available regarding its indications and feasibility. Also, laparoscopic two-stage hepatectomy is developing for bilobar CRLM, and this also does not have established recommendation. The purpose of this paper was to highlight novelty and updates in the field of multiple minimally invasive liver resections. A review of the international literature was performed. The feasibility of laparoscopic concomitant multiple LLR and two-stage hepatectomy for CRLM as well as their outcomes were discussed. These clarifications could further guide the implementation of minimal resection in multiple colorectal liver metastases therapies.

Laparoscopic parenchyma-sparing liver resection for large (≥ 50 mm) colorectal metastases

BACKGROUND

Traditionally, patients with large liver tumors (≥ 50 mm) have been considered for anatomic major hepatectomy. Laparoscopic resection of large liver lesions is technically challenging and often performed by surgeons with extensive experience. The current study aimed to evaluate the surgical and oncologic safety of laparoscopic parenchyma-sparing liver resection in patients with large colorectal metastases.

METHODS

Patients who primarily underwent laparoscopic parenchyma-sparing liver resection (less than 3 consecutive liver segments) for colorectal liver metastases between 1999 and 2019 at Oslo University Hospital were analyzed. In some recent cases, a computer-assisted surgical planning system was used to better visualize and understand the patients' liver anatomy, as well as a tool to further improve the resection strategy. The surgical and oncologic outcomes of patients with large (≥ 50 mm) and small (< 50 mm) tumors were compared. Multivariable Cox-regression analysis was performed to identify risk factors for survival.

RESULTS

In total 587 patients met the inclusion criteria (large tumor group, n = 59; and small tumor group, n = 528). Median tumor size was 60 mm (range, 50-110) in the large tumor group and 21 mm (3-48) in the small tumor group (p < 0.001). Patient age and CEA level were higher in the large tumor group (8.4 μg/L vs. 4.6 μg/L, p < 0.001). Operation time and conversion rate were similar, while median blood loss was higher in the large tumor group (500 ml vs. 200 ml, p < 0.001). Patients in the large tumor group had shorter 5 year overall survival (34% vs 49%, p = 0.027). However, in the multivariable Cox-regression analysis tumor size did not impact survival, unlike parameters such as age, ASA score, CEA level, extrahepatic disease at liver surgery, and positive lymph nodes in the primary tumor.

CONCLUSION

Laparoscopic parenchyma-sparing resections for large colorectal liver metastases provide satisfactory short and long-term outcomes.

Parenchyma-Sparing Liver Resection or Regenerative Liver Surgery: Which Way to Go?

Liver resection for malignant tumors should respect oncological margins while ensuring safety and improving the quality of life, therefore tumor staging, underlying liver disease and performance status should all be attentively assessed in the decision process. The concept of parenchyma-sparing liver surgery is nowadays used as an alternative to major hepatectomies to address deeply located lesions with intricate topography by means of complex multiplanar parenchyma-sparing liver resections, preferably under the guidance of intraoperative ultrasound. Regenerative liver surgery evolved as a liver growth induction method to increase resectability by stimulating the hypertrophy of the parenchyma intended to remain after resection (referred to as future liver remnant), achievable by portal vein embolization and liver venous deprivation as interventional approaches, and portal vein ligation and associating liver partition and portal vein ligation for staged hepatectomy as surgical techniques. Interestingly, although both strategies have the same conceptual origin, they eventually became caught in the never-ending parenchyma-sparing liver surgery vs. regenerative liver surgery debate. However, these strategies are both valid and must both be mastered and used to increase resectability. In our opinion, we consider parenchyma-sparing liver surgery along with techniques of complex liver resection and intraoperative ultrasound guidance the preferred strategy to treat liver tumors. In addition, liver volume-manipulating regenerative surgery should be employed when resectability needs to be extended beyond the possibilities of parenchyma-sparing liver surgery.

Generic surgical process model for minimally invasive liver treatment methods

Surgical process modelling is an innovative approach that aims to simplify the challenges involved in improving surgeries through quantitative analysis of a well-established model of surgical activities. In this paper, surgical process model strategies are applied for the analysis of different Minimally Invasive Liver Treatments (MILTs), including ablation and surgical resection of the liver lesions. Moreover, a generic surgical process model for these differences in MILTs is introduced. The generic surgical process model was established at three different granularity levels. The generic process model, encompassing thirteen phases, was verified against videos of MILT procedures and interviews with surgeons. The established model covers all the surgical and interventional activities and the connections between them and provides a foundation for extensive quantitative analysis and simulations of MILT procedures for improving computer-assisted surgery systems, surgeon training and evaluation, surgeon guidance and planning systems and evaluation of new technologies.

Long-term oncological outcomes after laparoscopic parenchyma-sparing redo liver resections for patients with metastatic colorectal cancer: a European multi-center study

Background

Laparoscopic redo resections for colorectal metastases are poorly investigated. This study aims to explore long-term results after second, third, and fourth resections.

Material and methods

Prospectively updated databases of primary and redo laparoscopic liver resections in six European HPB centers were analyzed. Procedure-related overall survival after first, second, third, and fourth resections were evaluated. Furthermore, patients without liver recurrence after first liver resection were compared to those with one redo, two or three redo, and patients with palliative treatment for liver recurrence after first laparoscopic liver surgery. Survival was calculated both from the date of the first liver resection and from the date of the actual liver resection. In total, 837 laparoscopic primary and redo liver resections performed in 762 patients were included (630 primary, 172 first redo, 29 second redo, and 6 third redo). Patients were bunched into four groups: Group 1—without hepatic recurrence after primary liver resection (n = 441); Group 2—with liver recurrence who underwent only one laparoscopic redo resection (n = 154); Group 3—with liver recurrence who underwent two laparoscopic redo resections (n = 29); Group 4—with liver recurrence who have not been found suitable for redo resections (n = 138).

Results

No significant difference has been found between the groups in terms of baseline characteristics and surgical outcomes. Rate of positive resection margin was higher in the group with palliative recurrence (group 4). Five-year survival calculated from the first liver resection was 67%, 62%, 84%, and 7% for group 1, 2, 3, and 4, respectively. Procedure-specific 5-year overall survival was 50% after primary laparoscopic liver resection, 52% after the 1st reoperation, 52% after the 2nd, and 40% after the 3rd reoperation made laparoscopic.

Conclusions

Multiple redo recurrences can be performed laparoscopically with good long-term results. Liver recurrence does not aggravate prognosis as long as the patient is suitable for reoperation.

Laparoscopic liver resection for colorectal liver metastases - short- and long-term outcomes: A systematic review

BACKGROUND

For well-selected patients and procedures, laparoscopic liver resection (LLR) has become the gold standard for the treatment of colorectal liver metastases (CRLM) when performed in specialized centers. However, little is currently known concerning patient-related and peri-operative factors that could play a role in survival outcomes associated with LLR for CRLM.

AIM

To provide an extensive summary of reported outcomes and prognostic factors associated with LLR for CRLM.

METHODS

A systematic search was performed in PubMed, EMBASE, Web of Science and the Cochrane Library using the keywords "colorectal liver metastases", "laparoscopy", "liver resection", "prognostic factors", "outcomes" and "survival". Only publications written in English and published until December 2019 were included. Furthermore, abstracts of which no accompanying full text was published, reviews, case reports, letters, protocols, comments, surveys and animal studies were excluded. All search results were saved to Endnote Online and imported in Rayyan for systematic selection. Data of interest were extracted from the included publications and tabulated for qualitative analysis.

RESULTS

Out of 1064 articles retrieved by means of a systematic and grey literature search, 77 were included for qualitative analysis. Seventy-two research papers provided data concerning outcomes of LLR for CRLM. Fourteen papers were eligible for extraction of data concerning prognostic factors affecting survival outcomes. Qualitative analysis of the collected data showed that LLR for CRLM is safe, feasible and provides oncological efficiency. Multiple research groups have reported on the short-term advantages of LLR compared to open procedures. The obtained results accounted for minor LLR, as well as major LLR, simultaneous laparoscopic colorectal and liver resection, LLR of posterosuperior segments, two-stage hepatectomy and repeat LLR for CRLM. Few research groups so far have studied prognostic factors affecting long-term outcomes of LLR for CRLM.

CONCLUSION

In experienced hands, LLR for CRLM provides good short- and long-term outcomes, independent of the complexity of the procedure.

Evolution of laparoscopic liver surgery: 20-year experience of a Norwegian high-volume referral center

BACKGROUND

Laparoscopic liver surgery has evolved to become a standard surgical approach in many specialized centers worldwide. In this study we present the evolution of laparoscopic liver surgery at a single high-volume referral center since its introduction in 1998.

METHODS

Patients who underwent laparoscopic liver resection (LLR) between August 1998 and December 2018 at the Oslo University Hospital were analyzed. Perioperative outcomes were compared between three time periods: early (1998 to 2004), middle (2005 to 2012) and recent (2013-2018).

RESULTS

Up to December 2020, 1533 LLRs have been performed. A total of 1232 procedures were examined (early period, n = 62; middle period, n = 367 and recent period, n = 803). Colorectal liver metastasis was the main indication for surgery (68%). The rates of conversion to laparotomy and hand-assisted laparoscopy were 3.2% and 1.4%. The median operative time and blood loss were 130 min [interquartile range (IQR), 85-190] and 220 ml (IQR, 50-600), respectively. The total postoperative complications rate was 20.3% and the 30-day mortality was 0.3%. The median postoperative stay was two (IQR, 2-4) days. When comparing perioperative outcomes between the three time periods, shorter operation time (median, from 182 to 120 min, p < 0.001), less blood loss (median, from 550 to 200 ml, p = 0.023), decreased rate of conversions to laparotomy (from 8 to 3%) and shorter postoperative hospital stay (median, from 3 to 2 days, p < 0.001) was observed in the later periods, while the number of more complex liver resections had increased.

CONCLUSION

During the last two decades, the indications, the number of patients and the complexity of laparoscopic liver procedures have expanded significantly. Initially being an experimental approach, laparoscopic liver surgery is now safely implemented across our unit and has become the method of choice for surgical treatment of most liver tumors.

The learning curve of laparoscopic ablation of liver tumors: A technically demanding procedure requiring dedicated training

BACKGROUND

Laparoscopic ablation (LA) of liver tumors is an increasingly performed procedure. However, LA is technically demanding, with inherent difficulties making LA more complex than percutaneous and open surgery ablations. This study aimed to characterize the learning curve (LC) of LAs.

METHODS

All consecutive LAs of malignant liver tumors performed with curative intent by a single surgeon were identified from a prospective database. A risk-adjusted cumulative summative (RA-CUSUM) analysis was used for evaluating the LC of LAs. Incomplete ablation (IA) was the outcomes measure. Performance trends were analyzed using broken-line modeling.

RESULTS

From June 2007 to February 2018, 241 lesions underwent LA during 151 procedures. RA-CUSUM analysis demonstrated an LC of 93 LAs (p < 0.001), with an IA rate decreasing from 12.9% to 4.7% (p = 0.027). Lesions in the posterosuperior segment and those in cirrhotic livers showed an LC of 34 and 45 tumor ablations, respectively (p=<0.001 each). Open ablations performed during the same period showed steady outcomes, indicating already acquired proficiency.

CONCLUSION

Completion of a steep LC is needed to gain proficiency in LAs. Dedicated training should be warranted to novices to smooth the LC and decrease LA failures.

Parenchymal Sparing Anatomical Liver Resections With Full Laparoscopic Approach: Description of Technique and Short-term Results

OBJECTIVE

The aim of this study was to describe laparoscopic anatomical parenchymal sparing liver resections for hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) and report the short-term outcomes.

BACKGROUND

Anatomical resections (ARs) have better oncological outcomes compared to partial resections in patients with HCC, and some suggest should be performed also for CRLM as micrometastasis occurs through the intrahepatic structures. Furthermore, remnant liver ischemia after partial resections has been associated with worse oncological outcomes. Few experiences on laparoscopic anatomical resections have been reported and no data on limited AR exist.

METHODS

We performed a retrospective analysis of 86 patients undergoing full laparoscopic anatomical parenchymal sparing resections with preoperative surgical simulation and standardized procedures.

RESULTS

A total of 55 patients had HCC, whereas 31 had CRLM with a median of 1 lesion and a size of 30 mm. During preoperative three-dimensional (3D) simulation, a median resection volume of 120 mL was planned. Sixteen anatomical subsegmentectomies, 56 segmentectomies, and 14 sectionectomies were performed. Concordance between preoperative 3D simulation and intraoperative resection was 98.7%. Two patients were converted, and 7 patients experienced complications. Subsegmentectomies had comparable blood loss (166 mL, P = 0.59), but longer operative time (426 min, P = 0.01) than segmentectomies (blood loss 222 mL; operative time 355 min) and sectionectomies (blood loss 120 mL; operative time 295 min). R0 resection and margin width remained comparable among groups.

CONCLUSIONS

A precise preoperative planning and a standardized surgical technique allow to pursue the oncological quality of AR enhancing the safety of the parenchyma sparing principle, reducing surgical stress through a laparoscopic approach.

Long-Term Oncologic Outcomes After Laparoscopic Versus Open Resection for Colorectal Liver Metastases : A Randomized Trial

BACKGROUND

Despite the recent worldwide dissemination of laparoscopic liver surgery, no high-level evidence supports the oncologic safety of this approach.

OBJECTIVE

To evaluate long-term oncologic outcomes after laparoscopic versus open liver resection in patients with colorectal metastases.

DESIGN

A single-center, assessor-blinded, randomized controlled trial (OSLO-COMET [Oslo Randomized Laparoscopic Versus Open Liver Resection for Colorectal Metastases Trial]). (ClinicalTrials.gov: NCT01516710).

SETTING

Oslo University Hospital, the only provider of liver surgery for the 3 million inhabitants of southeastern Norway.

PARTICIPANTS

Patients with resectable colorectal liver metastases were randomly assigned to have open or laparoscopic liver resection.

INTERVENTION

From February 2012 to January 2016, a total of 280 patients were included in the trial (laparoscopic surgery: n = 133; open surgery: n = 147).

MEASUREMENTS

The primary outcome was postoperative morbidity within 30 days. Five-year rates of overall and recurrence-free survival were predefined secondary end points.

RESULTS

At a median follow-up of 70 months, rates of 5-year overall survival were 54% in the laparoscopic group and 55% in the open group (between-group difference, 0.5 percentage point [95% CI, -11.3 to 12.3 percentage points]; hazard ratio, 0.93 [CI, 0.67 to 1.30]; P = 0.67). Rates of 5-year recurrence-free survival were 30% in the laparoscopic group and 36% in the open group (between-group difference, 6.0 percentage points [CI, -6.7 to 18.7 percentage points]; hazard ratio, 1.09 [CI, 0.80 to 1.49]; P = 0.57).

LIMITATION

The trial was not powered to detect differences in secondary end points and was not designed to address a noninferiority hypothesis for survival outcomes.

CONCLUSION

In this randomized trial of laparoscopic and open liver surgery, no difference in survival outcomes was found between the treatment groups. However, differences in 5-year overall survival up to about 10 percentage points in either direction cannot be excluded. This trial should be followed by pragmatic multicenter trials and international registries.

PRIMARY FUNDING SOURCE

The South-Eastern Norway Regional Health Authority.

Evaluation of a novel navigation platform for laparoscopic liver surgery with organ deformation compensation using injected fiducials

In laparoscopic liver resection, surgeons conventionally rely on anatomical landmarks detected through a laparoscope, preoperative volumetric images and laparoscopic ultrasound to compensate for the challenges of minimally invasive access. Image guidance using optical tracking and registration procedures is a promising tool, although often undermined by its inaccuracy. This study evaluates a novel surgical navigation solution that can compensate for liver deformations using an accurate and effective registration method. The proposed solution relies on a robotic C-arm to perform registration to preoperative CT/MRI image data and allows for intraoperative updates during resection using fluoroscopic images. Navigation is offered both as a 3D liver model with real-time instrument visualization, as well as an augmented reality overlay on the laparoscope camera view. Testing was conducted through a pre-clinical trial which included four porcine models. Accuracy of the navigation system was measured through two evaluation methods: liver surface fiducials reprojection and a comparison between planned and navigated resection margins. Target Registration Error with the fiducials evaluation shows that the accuracy in the vicinity of the lesion was 3.78±1.89 mm. Resection margin evaluations resulted in an overall median accuracy of 4.44 mm with a maximum error of 9.75 mm over the four subjects. The presented solution is accurate enough to be potentially clinically beneficial for surgical guidance in laparoscopic liver surgery.

Laparoscopic Versus Open Thermal Ablation of Colorectal Liver Metastases: A Propensity Score-Based Analysis of Local Control of the Ablated Tumors

BACKGROUND

Laparoscopic ablation (LA) of colorectal liver metastases (CRLMs) is frequently performed in combination with laparoscopic liver resection or as a stand-alone procedure. However, LA is technically demanding and whether the results are comparable with those of open ablation (OA) has not been determined to date. This study compared the effectiveness of LA and OA in achieving local tumor control of CRLMs.

METHODS

Patients undergoing LA or OA of CRLMs at Ghent University Hospital between June 2007 and February 2018 were identified from a prospective database. Lesions treated by LA and OA were matched 1:1 using a propensity score based on lesions (liver segment, size, deepness, proximity to a vessel), patients, and procedural characteristics. Ablation sites were followed up with computed-tomography or magnetic resonance imaging to assess the completeness of the ablation and ablation-site recurrence (ASR). Analysis of ASR was performed with the Kaplan-Meier method and Cox regression.

RESULTS

In this study, 163 patients underwent the surgical ablation (78 LA, 85 OA) of 333 CRLMs (143 LA, 190 OA). After matching, 220 lesions (110 LA, 110 OA) were analyzed. Ablation was complete in 93.7% (LA) and 97.3% (OA) of the sites (p = 0.195). No difference in ASR was observed (p = 0.351), with a cumulative risk of ASR at 12 months of 9.1% (LA) and 8.2% (OA). After multivariable analysis, ASR was confirmed to be independent of the surgical approach.

CONCLUSION

The findings showed that LA and OA achieve a comparable local control of CRLMs. This result further supports the adoption of a laparoscopic approach for the treatment of CRLMs.

Ultrasound Based Planning and Navigation for Non-Anatomical Liver Resections – An Ex-Vivo Study

Goal: Non-anatomical resections of liver tumors can be very challenging as the surgeon cannot use anatomical landmarks on the liver surface or in the ultrasound image for guidance. This makes it difficult to achieve negative resection margins (R0) and still preserve as much healthy liver tissue as possible. Even though image-guided surgery systems have been introduced to overcome this challenge, they are still rarely used due to their inaccuracy, time-effort and complexity in usage and setup. Methods: We have developed a novel approach, which allows us to create an intra-operative resection plan using navigated ultrasound. First, the surface is scanned using a navigated ultrasound, followed by tumor segmentation on a midsection ultrasound image. Based on this information, the navigation system calculates an optimal resection strategy and displays it along with the tracked surgical instruments. In this study, this approach was evaluated by three experienced hepatobiliary surgeons on ex-vivo porcine models. Results: Using this technique, an R0 resection could be achieved in 22 out of 23 (95.7% R0 resection rate) cases with a median resection margin of 5.9 mm (IQR 3.5–7.7 mm). The resection margin between operators 1, 2 and 3 was 7.8 mm, 4.15 mm and 5.1 mm respectively (p = 0.054). Conclusions: This approach could represent a useful tool for intra-operative guidance in non-anatomical resection alongside conventional ultrasound guidance. However, instructions and training are essential especially if the operator has not used an image-guidance system before.

The effect of intraoperative imaging on surgical navigation for laparoscopic liver resection surgery

Conventional surgical navigation systems rely on preoperative imaging to provide guidance. In laparoscopic liver surgery, insufflation of the abdomen (pneumoperitoneum) can cause deformations on the liver, introducing inaccuracies in the correspondence between the preoperative images and the intraoperative reality. This study evaluates the improvements provided by intraoperative imaging for laparoscopic liver surgical navigation, when displayed as augmented reality (AR). Significant differences were found in terms of accuracy of the AR, in favor of intraoperative imaging. In addition, results showed an effect of user-induced error: image-to-patient registration based on annotations performed by clinicians caused 33% more inaccuracy as compared to image-to-patient registration algorithms that do not depend on user annotations. Hence, to achieve accurate surgical navigation for laparoscopic liver surgery, intraoperative imaging is recommendable to compensate for deformation. Moreover, user annotation errors may lead to inaccuracies in registration processes.

Laparoscopic versus open liver resection in the posterosuperior segments: a sub-group analysis from the OSLO-COMET randomized controlled trial

BACKGROUND

Laparoscopic liver resection in the posterosuperior segments is technically challenging. This study aimed to compare the perioperative outcomes for laparoscopic and open resection of colorectal liver metastases located in the posterosuperior segments.

METHODS

This was a subgroup analysis of the OSLO-COMET randomized controlled trial, where 280 patients were randomly assigned to open or laparoscopic parenchyma-sparing liver resections of colorectal metastases. Patients with tumors in the posterosuperior segments were identified, and perioperative outcomes and health related quality of life (HRQoL) were compared.

RESULTS

We identified a total of 136 patients, 62 in the laparoscopic and 74 in the open group. The postoperative complication rate was 26% in the laparoscopic and 31% in the open group. The blood loss was less in the open group (500 vs. 250 ml, P = 0.006), but the perioperative transfusion rate was similar. The operative time was similar, while postoperative hospital stay was shorter in the laparoscopic group (2 vs. 4 days, P < 0.001). HRQoL was significantly better after laparoscopy at 1 month.

CONCLUSION

In patients undergoing laparoscopic or open liver resection of colorectal liver metastases in the posterosuperior segments, laparoscopic surgery was associated with shorter hospital stay and comparable perioperative outcomes.

Laparoscopic liver resection for non-colorectal non-neuroendocrine metastases: perioperative and oncologic outcomes

BACKGROUND

Liver resection is a treatment of choice for colorectal and neuroendocrine liver metastases, and laparoscopy is an accepted approach for surgical treatment of these patients. The role of liver resection for patients with non-colorectal non-neuroendocrine liver metastases (NCNNLM), however, is still disputable. Outcomes of laparoscopic liver resection for this group of patients have not been analyzed.

MATERIAL AND METHODS

In this retrospective study, patients who underwent laparoscopic liver resection for NCNNLM at Oslo University Hospital between April 2000 and January 2018 were analyzed. Perioperative and oncologic data of these patients were examined. Postoperative morbidity was classified using the Accordion classification. Kaplan-Meier method was used for survival analysis. Median follow-up was 26 (IQR, 12-41) months.

RESULTS

Fifty-one patients were identified from a prospectively collected database. The histology of primary tumors was classified as adenocarcinoma (n = 16), sarcoma (n = 4), squamous cell carcinoma (n = 4), melanoma (n = 16), gastrointestinal stromal tumor (n = 9), and adrenocortical carcinoma (n = 2). The median operative time was 147 (IQR, 95-225) min, while the median blood loss was 200 (IQR, 50-500) ml. Nine (18%) patients experienced postoperative complications. There was no 90-day mortality in this study. Thirty-five (68%) patients developed disease recurrence or progression. Seven (14%) patients underwent repeat surgical procedure for recurrent liver metastases. One-, three-, and five-year overall survival rates were 85%, 52%, and 38%, respectively. The median overall survival was 37 (95%CI, 25 to 49) months.

CONCLUSION

Laparoscopic liver resection for NCNNLM results in good outcomes and should be considered in patients selected for surgical treatment.

Use of mixed reality for improved spatial understanding of liver anatomy

Introduction: In liver surgery, medical images from pre-operative computed tomography and magnetic resonance imaging are the basis for the decision-making process. These images are used in surgery planning and guidance, especially for parenchyma-sparing hepatectomies. Though medical images are commonly visualized in two dimensions (2D), surgeons need to mentally reconstruct this information in three dimensions (3D) for a spatial understanding of the anatomy. The aim of this work is to investigate whether the use of a 3D model visualized in mixed reality with Microsoft HoloLens increases the spatial understanding of the liver, compared to the conventional way of using 2D images.Material and methods: In this study, clinicians had to identify liver segments associated to lesions.Results: Twenty-eight clinicians with varying medical experience were recruited for the study. From a total of 150 lesions, 89 were correctly assigned without significant difference between the modalities. The median time for correct identification was 23.5 [4-138] s using the magnetic resonance imaging images and 6.00 [1-35] s using HoloLens (p < 0.001).Conclusions: The use of 3D liver models in mixed reality significantly decreases the time for tasks requiring a spatial understanding of the organ. This may significantly decrease operating time and improve use of resources.

Liver segment imaging using monocyte sequestration: a potential tool for fluorescence-guided liver surgery

Background: The accurate determination of liver segment anatomy is essential to perform liver resection without complications and to ensure long-term outcomes after this operation. There are several perioperative methods for segment identification and surgical navigation, such as intraoperative ultrasound, indigo carmine and near-infrared imaging with indocyanine green. The present study experimentally analyzed the usefulness of monocyte sequestration for liver segment labeling and imaging.

Methods: Human monocytes were isolated from peripheral blood and directly or indirectly labeled with calcein or IRDye 800CW. Potential toxicity, labeling stability, and adhesion to ICAM-1 were analyzed in vitro. Monocyte sequestration in the liver microvasculature and liver segment labeling and boundary demarcation were studied using isolated mouse and pig liver perfusion and via intraportal injection in mouse liver tumor models.

Results: The highest monocyte labeling efficiency was achieved using direct labeling with IRDye 800CW. Labeling was stable and did not influence cell viability. The labeled monocytes were highly sequestrated in the liver microvasculature, both after ex vivo perfusion and after injection in vivo , resulting in excellent labeling of selected liver segments and strong segment boundary demarcation. In contrast to results to a normal liver, monocyte sequestration was very low in tumor-associated blood vessels.

Conclusions: The present experimental study shows that sequestration of labeled monocytes after superselective application demarcates the selected liver segment. These results illustrate potential of this technique for surgical navigation during liver surgery.