A Comparison of Near-Infrared Autofluorescence Findings in Benign Versus Malignant Adrenal Tumors.

BACKGROUND: Many adrenal tumors are deemed radiologically indeterminate and surgically removed. Adrenal tissue, like parathyroid glands, exhibits near-infrared autofluorescence (NIRAF) properties. This study was designed to investigate the potential of NIRAF to differentiate benign versus malignant adrenal tumors. METHODS: Patients undergoing adrenalectomy between October 2021 and May 2023 were prospectively studied. Adrenalectomy specimens were inspected with NIRAF imaging. Specimen autofluorescence (AF) characteristics were recorded. Comparisons were made between different tumor types and a logistic regression model was constructed to differentiate benign versus malignant tumors. A receiver operating characteristic curve was used to identify an optimal AF threshold differentiating benign versus malignant tumors. RESULTS: A total of 108 adrenal specimens were examined: adrenocortical adenomas/other benign lesions (n = 72), pheochromocytomas (n = 18), adrenocortical neoplasms of uncertain behavior (n = 4), and malignant tumors (n = 14). A significant difference in normalized AF intensity was identified when comparing adrenocortical adenomas (3.08 times background) with pheochromocytomas (1.95, p = 0.001) and malignant tumors (1.11, p < 0.0001). The Area Under the Curve differentiating benign vs malignant tumors was 0.87, with an optimal normalized AF threshold at 1.93. CONCLUSIONS: Different adrenal pathologies exhibit diverse AF properties. These findings suggest a potential intraoperative utility of NIRAF in predicting benign versus malignant nature for radiologically indeterminate adrenal tumors.

An update on the use of near-infrared autofluorescence imaging in endocrine surgical procedures.

Over the past decade, near-infrared autofluorescence (NIRAF) imaging has been a major breakthrough in endocrine surgery. Although initial focus was directed at the parathyroid glands, subsequent work has also shown that non-parathyroid neuroendocrine tumors also possess autofluorescence properties. The aim of this review is to present an update and synopsis about NIRAF applications in various endocrine surgical procedures. Methodology includes a review of the literature supplemented with expert opinion. Overall, our review reveals that the use of NIRAF may provide the surgeon with adjunctive critical information that has the potential to change the conduct of many various endocrine surgical procedures.

Laparoscopic versus robotic lateral transabdominal adrenalectomy.

BACKGROUND AND OBJECTIVES: Despite an increased adaptation of robotic adrenalectomy, its advantages over laparoscopic adrenalectomy (LA) have not been defined. The aim of the study was to compare perioperative outcomes of robotic versus laparoscopic lateral transabdominal adrenalectomy using a large single-center experience. METHODS: This was a retrospective single center study. Within 22 years, patients who underwent laparoscopic and robotic transabdominal lateral adrenalectomy were identified from a prospective institutional review board-approved database. Clinical and perioperative outcomes were compared using Mann-Whitney U and χ2  tests. RESULTS: There were 190 patients who underwent laparoscopic and 281 patients who underwent robotic transabdominal lateral adrenalectomy. The groups were comparable except for a higher percentage of female patients in the robotic group. For robotic versus LA, operative time and hospital stay were shorter, in addition to less blood loss, conversion to open and margin positivity, for pheochromocytoma and malignant tumors. Morbidity rates were similar between the two groups. CONCLUSIONS: Despite the limitations of a retrospective design, this large study demonstrates significant advantages of robotic versus laparoscopic transabdominal lateral adrenalectomy in terms of perioperative outcomes and margin clearance.

A comparison of three different microwave systems for laparoscopic liver tumor ablation.

BACKGROUND: Our aim was to perform a comparison of three current microwave ablation (MWA) systems widely used for laparoscopic liver ablations in terms of ablation kinetics and geometry of ablation zones. METHODS: This was a retrospective, institutional review board-approved study comparing Emprint, Emprint HP, and NeuWave systems for laparoscopic liver ablation. Analyses were performed via Mann-Whitney U and χ2 tests. Continuous data are presented as median (interquartile range). RESULTS: For Emprint, Emprint HP, and NeuWave groups, tumor size was 1.16 (0.8), 1.21 (0.7), and 1.27 (0.9) cm (p = 0.54). Ablation time per lesion was 7 (6), 4 (2.8), and 4 (3.3) min (p < 0.0001), yielding similar ablation zone volumes and margins. The time to first ablation bubble was 1 (0.13), 1.5 (0.85), and 0.75 (0.5) min, and total ablation times were 7 (4.4), 4 (2), and 3.5 (2.8) min (p < 0.0001). The roundness index A, B, and transverse were 0.94, 0.98, and 0.79; 0.95, 0.95, and 0.78; and 1.02, 0.95, and 0.96. CONCLUSIONS: Although a saline-cooling system with Emprint system allowed for larger diameter spherical ablation zones to be created, it led to decreased efficiency compared to the CO2-cooled NeuWave system, which exposes the active antenna directly to tissue. Increased power delivered by Emprint HP improved the efficiency of saline-cooled design, as demonstrated by faster ablation times.

A New Disease Severity Score for Measuring Treatment Response to Adrenalectomy in Patients With Primary Aldosteronism.

OBJECTIVE: Cure after adrenalectomy for primary aldosteronism has been reported in only 15% to 40% of patients, with no disease severity score available to measure response objectively. Furthermore, the criteria used to define cure are outdated. This study aims to determine the rate of cure based on the current definition of normal blood pressure and develop a disease severity score to measure clinical improvement after adrenalectomy for primary aldosteronism. METHODS: This was a retrospective single-center study that included patients who underwent adrenalectomy for primary aldosteronism between 2000 and 2023. Blood pressure, a defined daily dose of antihypertensives, and potassium supplementation were incorporated into a new Primary Aldosteronism Disease Severity Score (PADSS), which was calculated with preoperative and 6-month postoperative parameters. RESULTS: The study included 201 patients. Adrenalectomy was guided by adrenal venous sampling in 86.1% of patients. The cure rate per the new definition of normal blood pressure was 7.5% (n = 15). The median PADSS was 16.3 (13.6-19.9) preoperatively and decreased to 10 (4.5-13.3) postoperatively. An improvement of the PADSS was observed in 90% (n = 180) of patients at 6 months of adrenalectomy. The median rate of improvement in PADSS was 33.3% (13.8% to 56.6%). CONCLUSIONS: Although complete cure rates are low after adrenalectomy in primary aldosteronism, especially based on the new definition of normal blood pressure, a clinical improvement is seen in the vast majority of patients postoperatively. The newly introduced PADSS can be used to assess the clinical benefit achieved with adrenalectomy.

Anastomosing haemangioma of the adrenal gland: A clinicopathological series of seven cases.

AIMS: Anastomosing haemangioma is a rare benign vascular neoplasm that may histologically mimic angiosarcoma. We report the largest single institution series of anastomosing haemangioma in the adrenal gland with emphasis on clinical and radiological features. METHODS AND RESULTS: Our laboratory information system was searched for a 25-year period (1999-2023), yielding seven cases confirmed as anastomosing haemangioma of the adrenal gland after pathological re-review. Clinical, radiological and pathological information was obtained from medical charts and submitting pathologists. Of a total of seven patients, four (57.1%) were men and three women, ranging in age from 37 to 75 years (mean = 61). Six of seven patients underwent adrenalectomies and one had radical nephrectomy. Tumours ranged from 0.7 to 6.4 cm (mean = 2.1 cm) and five of seven (71%) were grossly well-circumscribed. Five of seven lesions were found incidentally at imaging for other indications. All tumours were unifocal except one, which presented with multifocal disease with a concurrent adjacent retroperitoneal anastomosing haemangioma. Three of five tumours imaged with contrast enhancement were almost completely hyperenhancing with a small central non-enhancing portion, features overlapping with pheochromocytoma. One of seven tumours involved the peri-adrenal adipose tissue with a focally infiltrative pattern. There were no recurrences or metastases in six patients with available follow-up data (median = 95 months). CONCLUSIONS: Benign anastomosing haemangiomas of the adrenal gland tend to occur in older patients, may mimic pheochromocytoma on imaging and must be distinguished from angiosarcoma pathologically. Better awareness of this entity by pathologists, radiologists and surgeons is crucial to appropriate work-up, diagnosis and management.

Laparoscopic versus robotic adrenalectomy in severely obese patients.

BACKGROUND: Over the last 20 years, the prevalence of severe obesity (body mass index ≥ 35 kg/m2) has almost doubled. This condition increases the challenge of laparoscopic adrenalectomy (LA) by creating problems with instrument reach, adequate exposure, and visualization. The aim was to compare perioperative outcomes of laparoscopic versus robotic adrenalectomy (RA) in severely obese patients. METHODS: This was an institutional review board-approved retrospective study. Prospectively collected clinical parameters of patients who underwent LA versus RA between 2000 and 2021 at a single center were compared using Mann-Whitney U, ANOVA, Chi-square, and multivariate regression analysis. Continuous data are expressed as median (interquartile range). RESULTS: For lateral transabdominal (LT) adrenalectomies, skin-to-skin operative time (OT) [164.5 (71.0) vs 198.8 (117.0) minutes, p = 0.006] and estimated blood loss [26.2 (15.0) vs 72.6 (50.0) ml, p = 0.010] were less in RA versus LA group, respectively. Positive margin rate, hospital stay and 90-day morbidity were similar between the groups (p = NS). For posterior retroperitoneal (PR) approach, operative time and perioperative outcomes were similar between LA and RA groups. Multivariate analysis demonstrated robotic versus laparoscopic technique (p = 0.006) to be an independent predictor of a shorter OT. CONCLUSION: There was a benefit of robotic over the laparoscopic LT adrenalectomy regarding OT and estimated blood loss. Although limited by the small sample size, there was no difference regarding perioperative outcomes between RA and LA performed through a PR approach.

A Modern Assessment of Cancer Risk in Adrenal Incidentalomas: Analysis of 2219 Patients.

OBJECTIVE: The aim of this study was to analyze the incidence of and risk factors for adrenocortical carcinoma (ACC) in adrenal incidentaloma (AI). SUMMARY OF BACKGROUND DATA: AI guidelines are based on data obtained with old-generation imaging and predominantly use tumor size to stratify risk for ACC. There is a need to analyze the incidence and risk factors from a contemporary series. METHODS: This is a retrospective review of 2219 AIs that were either surgically removed or nonoperatively monitored for ≥12 months between 2000 and 2017. Multivariate logistic regression was performed to define risk factors. ROC curves constructed to determine optimal size and attenuation cut-offs for ACC. RESULTS: 16.8% of AIs underwent upfront surgery and rest initial nonoperative management. Of conservatively managed patients, an additional 7.7% subsequently required adrenalectomy. Overall, ACC incidence in AI was 1.7%. ACC rates by size were 0.1%, 2.4%, and 19.5% for AIs of <4, 4 to 6, and >6 cm, respectively. The optimal size cut-off for ACC in AI was 4.6 cm. ACC risks by Hounsfield density were 0%, 0.5%, and 6.3% for lesions of <10, 10 to 20, and >20 HU, with an optimal cut-off of 20 HU to diagnose ACC. 15.5% of all AIs and 19.2% of ACCs were hormonally active. Male sex, large tumor size, high Hounsfield density, and >0.6 cm/year growth were independent risk factors for ACC. CONCLUSION: This contemporary analysis demonstrates that ACC risk per size in AI is less than previously reported. Given these findings, modern management of AIs should not be based just on size, but a combination of thorough hormonal evaluation and imaging characteristics.

A Visual Deep Learning Model to Localize Parathyroid-Specific Autofluorescence on Near-Infrared Imaging : Localization of Parathyroid Autofluorescence with Deep Learning.

BACKGROUND AND PURPOSE: Parathyroid glands may be detected by their autofluorescence on near-infrared imaging. Nevertheless, recognition of parathyroid-specific autofluorescence requires a learning curve, with other unrelated bright signals causing confusion. The aim of this study was to find out whether machine learning could be used to facilitate identification of parathyroid-specific autofluorescence signals on intraoperative near-infrared images in patients undergoing thyroidectomy and parathyroidectomy procedures. METHODS: In an institutional review board-approved study, intraoperative near-infrared images of patients who underwent thyroidectomy and/or parathyroidectomy procedures within a year were used to develop an artificial intelligence model. Parathyroid-specific autofluorescence signals were marked with rectangles on intraoperative near-infrared still images and used for training a deep learning model. A randomly chosen 80% of the data were used for training, 10% for testing, and 10% for validation. Precision and recall of the model were calculated. RESULTS: A total of 466 intraoperative near-infrared images of 197 patients who underwent thyroidectomy and/or parathyroidectomy procedures were analyzed. Procedures included total thyroidectomy in 54 patients, thyroid lobectomy in 24 patients, parathyroidectomy in 108 patients, and combined thyroidectomy and parathyroidectomy procedures in 11 patients. The overall recall and precision of the model were 90.5 and 95.7%, respectively. CONCLUSIONS: To our knowledge, this is the first study that describes the use of artificial intelligence tools to assist in recognition of parathyroid-specific autofluorescence signals on near-infrared imaging. The model developed may have utility in facilitating training and decreasing the learning curve associated with the use of this technology.

Assessment of a new 150 W single-antenna microwave ablation system in the treatment of malignant liver tumors: The first worldwide experience.

BACKGROUND AND OBJECTIVES: Data in literature regarding liver microwave ablation pertain to systems delivering 100 W of maximum power. Our aim is to assess a new 150 W microwave system for liver tumor ablation. METHODS: This was an institutional review board-approved study of patients undergoing ablation of malignant liver tumors using a 150 W microwave system. Feasibility, safety, ablation algorithm, perioperative outcomes, and efficacy were analyzed. Comparison was made to historical patients undergoing ablation using a 100 W microwave system. RESULTS: There were 33 patients with 76 malignant liver lesions who underwent ablation with the 150 W system. Using a step-wise algorithm, ablations without intraoperative complications were performed for tumors ranging in size from 0.3 to 6.7 cm. Ninety-day morbidity was 5%, with no mortality. Compared to the 100 W system, the 150 W system shortened ablation time and created larger ablation zones with a single stick. CONCLUSION: This first worldwide experience showed that surgical ablations could be safely created at 150 W using a step-wise algorithm with complete tumor destruction achieved at short-term follow-up. Advantages versus 100 W systems include reduction in ablation time and creation of larger ablation zones with a single stick.

The utility of near infrared autofluorescence imaging for detecting small bowel carcinoid tumors in comparison to DOTATATE PET: A pilot study.

BACKGROUND: Small bowel carcinoid (SBC) primary tumors can be multifocal in 40%-55% of patients and challenging to detect. Near infrared autofluorescence (NIRAF) is used for detection of parathyroid glands. It is unknown if this technology can be used to identify SBCs and how it would compare with current imaging modalities. METHODS: This was a prospective institutional review board-approved pilot study of three patients undergoing resection of SBCs. NIRAF was used to image SBCs and mesenteric lymph nodes intraoperatively and at back table. Findings were compared with preoperative imaging, surgical exploration and pathology. Statistics were performed using Mann-Whitney U test. RESULTS: Eleven SBCs and 12 mesenteric lymph nodes were analyzed. All SBCs had a brighter focal autofluorescence (AF) signal compared to background. Normalized pixel intensity of SBCs was 2.2 (0.7) and normal small bowel 1.4 (0.6) (p < 0.0001). NIRAF was less accurate in detecting occult lymph node metastasis, but was superior to DOTATATE PET for detecting SBCs in two of three patients. CONCLUSIONS: This preliminary report suggests that SBCs exhibit distinctly bright AF signals on NIRAF to create a contrast distinction from normal small bowel. This technology may have a utility as an adjunctive tool for intraoperative detection of occult SBCs.

A visual deep learning model to predict abnormal versus normal parathyroid glands using intraoperative autofluorescence signals.

BACKGROUND: Previous work demonstrated that abnormal versus normal parathyroid glands (PGs) exhibit different patterns of autofluorescence, with former appearing darker and more heterogenous. Our objective was to develop a visual artificial intelligence model using intraoperative autofluorescence signals to predict whether a PG is abnormal (hypersecreting and/or hypercellular) or normal before excision during surgical exploration for primary hyperparathyroidism. METHODS: A total of 906 intraoperative parathyroid autofluorescence images of 303 patients undergoing parathyroidectomy/thyroidectomy were used to develop model. Autofluorescence image of each PG was uploaded into the visual artificial intelligence platform as abnormal or normal. For deep learning, randomly chosen 80% of data was used for training, 10% for testing, 10% for validation. The area under the receiver operating characteristic (AUROC), area under the precision-recall curve (AUPRC), recall (sensitivity), and precision (positive predictive value) of the model were calculated. RESULTS: AUROC and AUPRC of the model to predict normal and abnormal PGs were 0.90 and 0.93, respectively. Recall and precision of the model were 89% each. CONCLUSION: Visual artificial intelligence platforms may be used to compare the autofluorescence signal of a given parathyroid gland against a large database. This may be a new adjunctive tool for intraoperative assessment of parathyroid glands during surgical exploration for primary hyperparathyroidism.

Laparoscopic versus robotic adrenalectomy in pheochromocytoma patients.

BACKGROUND AND OBJECTIVES: Pheochromocytoma is a challenging tumor type requiring resection with a clear margin and an intact capsule to prevent recurrences. Our aim was to compare perioperative outcomes of laparoscopic adrenalectomy (LA) versus robotic adrenalectomy (RA) for pheochromocytoma. METHODS: In an institutional review board-approved retrospective study, clinical parameters of patients who underwent LA versus RA at a single center were compared using Mann-Whitney U, χ2 , and survival analyses. Continuous data are expressed as median (interquartile range). RESULTS: There was a total of 157 patients (RA: n = 87, LA: n = 70) analyzed. Estimated blood loss (36.3 [35.0] vs. 99.9 [65.0] cc, p = 0.020) and hospital stay (1.3 [0.0] vs. 2.2 [1.0] days, p = 0.010) were lower in robotic versus laparoscopic group, respectively. Disease-free and overall survival was similar between groups. The rate of conversion to open for tumors ≥5 cm was less in the robotic group (0% vs. 14%, respectively, p = 0.048). CONCLUSION: In this study, long-term outcomes of LA and RA were similar, although adrenalectomies performed robotically were associated with less blood loss, shorter hospital stay, and a lower chance of conversion to open in the case of large tumors.

Detection of near-infrared autofluorescence from adrenal neoplasms: An initial experience.

BACKGROUND AND OBJECTIVES: Fluorescence from adrenal tumors can be detected with near-infrared imaging after injection with indocyanine green. However, it is unknown if adrenal tumors exhibit autofluorescence. The aim of this study was to determine whether adrenal tumors emit near-infrared autofluorescence (NIRAF). METHODS: This was a prospective study of patients who underwent minimally invasive adrenalectomy at a tertiary center. Intraoperative images were analyzed to detect NIRAF with a 750 nm camera. Descriptive and comparative statistical analyses were performed. RESULTS: Twenty-five adrenalectomies were examined. Only 11 tumors (44%), that originated from the cortex exhibited autofluorescence. A contrast distinction between the tumor and retroperitoneum was observed in 23 patients, whereas a contrast distinction between the tumor and normal adrenocortical tissue was seen in 12 patients. The overall fluorescence intensity of adrenal tumors was found to be variable and ranging between 0.3 and 5.6 times that of the background tissue. Pheochromocytoma, malignancy and adrenal cyst did not demonstrate NIRAF. CONCLUSION: This is the first study to show that adrenocortical tissue can demonstrate NIRAF. The pattern of fluorescence was similar to that observed after indocyanine green injection in our historical experience. NIRAF has a potential to be used as an intraoperative optical adjunct during adrenalectomy.

The efficacy of laparoscopic transversus abdominis plane block on reducing postoperative narcotic usage in patients undergoing minimally invasive adrenalectomy.

BACKGROUND: Post-operative pain relief after abdominal operations is critical for patient satisfaction and rapid recovery. Narcotics have been a traditional part of postoperative analgesia, with transversus abdominis plane (TAP) block introduced recently. The aim of this study is to assess the efficacy of laparoscopic TAP block on postoperative pain control in patients undergoing minimally invasive adrenalectomy. METHODS: This was an institutional review board-approved retrospective study. Parameters related to postoperative pain control were compared between patients who underwent robotic transabdominal lateral adrenalectomy with (after December 2018) or without laparoscopic TAP block (control group) (before December 2018) by one surgeon. Statistics were performed using Mann Whitney U and Chi-square tests. RESULTS: There were 86 patients in the TAP and 83 patients in the control group. Groups were similar regarding demographic and clinical parameters. Despite the availability of intravenous acetaminophen to a higher percentage of patients in the control (31.3%) versus the TAP group (8.1%), 0-24 h lowest postoperative pain scores were significantly lower in the TAP group (P < 0.0001). In TAP versus control group, percentage of patients requiring narcotics and amount of narcotics used was lower (P = 0.04 vs P = 0.0004, respectively). Mainly due to less pain-related over-stay, percentage of patients requiring more than a day of hospital stay was less in the TAP (12%) versus control group (18%) (P = 0.01). CONCLUSION: To our knowledge, the utility of TAP block in patients undergoing minimally invasive adrenalectomy has not been reported in the past. This study shows that there may be benefits of laparoscopic TAP block in reducing post-operative narcotic usage while improving pain control in these patients.

Biochemical assessment of adrenal insufficiency after adrenalectomy for non-cortisol secreting tumors: clinical correlation and recommendations.

BACKGROUND: Data regarding changes in cortisol axis after adrenalectomy for non-cortisol secreting tumors and their correlation with adrenal insufficiency are limited. Our aim was to analyze these changes and their clinical correlations to guide management after adrenalectomy for non-Cushing's tumors. METHODS: Following IRB approval, postoperative cortisol axis changes were analyzed in patients who underwent unilateral adrenalectomy for non-Cushing's tumors. A morning serum cortisol of ≥ 10 µg/dl was accepted as a sufficient adrenal response. RESULTS: 223 adrenalectomies were analyzed. In 63% of patients, POD1 serum cortisol was ≥ 10 µg/dl and in 37% < 10 µg/dl. No patient with a POD1 cortisol ≥ 10 µg/dl developed AI symptoms, whereas symptoms of AI were observed in 4% of those with < 10 µg/dl. In patients with a POD1 cortisol of < 10 µg/dl, the rate of steroid replacement therapy initiation was 100%, 8%, and 25% when the decision was based on serum cortisol, clinical symptoms, and serum cortisol plus ACTH stimulation test results, respectively. In 90% of asymptomatic patients, hypocortisolemia resolved uneventfully within a week on repeat morning cortisol testing. 75% of patients with hypocortisolemia on POD1 demonstrated an adequate cortisol response to ACTH stimulation test. CONCLUSION: Although postoperative hypocortisolemia was observed in 37% of patients undergoing unilateral adrenalectomy for non-cortisol secreting tumors, majority did not develop symptoms of adrenal insufficiency. All three steroid initiation approaches appeared safe, with management based on clinical symptoms or selective ACTH stimulation testing sparing more patients from steroids compared to steroid initiation based on POD 1 cortisol levels alone.

A visual quantification of tissue distinction in robotic transabdominal lateral adrenalectomy: comparison of indocyanine green and conventional views.

BACKGROUND: Recent studies have reported the feasibility of indocyanine green fluorescence imaging of adrenal tumors to guide dissection. Although the adrenal has been reported to concentrate the dye more than surrounding tissues, the amount of tissue distinction and how this compares with conventional vision has not been quantified before. The aim of this study is to quantify this distinction using color analysis. METHODS: This was an institutional review board-approved retrospective study. By excluding adrenal cortical carcinoma, metastasis and pheochromocytoma, video recordings of 50 patients who underwent robotic transabdominal lateral adrenalectomy with indocyanine green (ICG) imaging for adrenocortical tumors between August 2015 and May 2018 were reviewed. Using a color analysis software, the pixel intensity of adrenal tumors versus adjacent retroperitoneal tissues was calculated for conventional red, green and blue, as well as indocyanine green (ICG) scales. Statistical analysis was performed using ANOVA. RESULTS: A total of 50 patients underwent unilateral robotic transabdominal lateral adrenalectomy. All procedures were completed robotically without a conversion to laparoscopy or open. Morbidity was 4%. Measured pixel intensity of adrenal tumors was higher than adjacent retroperitoneal tissues for all conventional color and ICG modes (p < 0.0001), with the gradient being more pronounced for ICG green versus conventional red, green and blue modes. CONCLUSIONS: To our knowledge this is the first study attempting to encode tissue planes in robotic adrenalectomy. The results show that the visual contrast distinction observed between adrenal and adjacent retroperitoneal tissues can be quantified using pixel intensity. ICG enabled the distinction of tissue planes with a wider gradient compared to conventional RGB view, quantifying its subjective benefits reported in prior studies.

The utility of laparoscopic ultrasound during minimally invasive liver procedures in patients with malignant liver tumors who have undergone preoperative magnetic resonance imaging.

BACKGROUND: The aim of this study was to assess the utility of laparoscopic ultrasound (LUS) during minimally invasive liver procedures in patients with malignant liver tumors who underwent preoperative magnetic resonance imaging (MRI). METHODS: Medical records of patients with malignant liver lesions who underwent laparoscopic liver surgery between October 2005 and January 2018 and who underwent an MRI examination at our institution within a month before surgery were collected from a prospectively maintained database. The size and location of tumors detected on LUS, as well as whether they were seen on preoperative imaging, were recorded. Univariate and multivariate regression analyses were performed to identify factors that were associated with the detection of liver lesions on LUS that were not seen on preoperative MRI. RESULTS: A total of 467 lesions were identified in 147 patients. Tumor types included colorectal cancer metastasis (n = 53), hepatocellular cancer (n = 38), neuroendocrine metastasis (n = 23), and others (n = 33). Procedures included ablation (67%), resection (23%), combined resection and ablation (6%), and diagnostic laparoscopy with biopsy (4%). LUS identified 39 additional lesions (8.4%) that were not seen on preoperative MRI in 14 patients (10%). These were colorectal cancer (n = 20, 51%), neuroendocrine (n = 11, 28%) and other metastases (n = 8, 21%). These additional findings on LUS changed the treatment plan in 13 patients (8.8%). Factors predicting tumor detection on LUS but not on MRI included obesity (p = 0.02), previous exposure to chemotherapy (p < 0.001), and lesion size < 1 cm (p < 0.001). CONCLUSION: This study demonstrates that, despite advances in MRI, LUS performed during minimally invasive liver procedures may detect additional tumors in 10% of patients with liver malignancies, with the highest yield seen in obese patients with previous exposure to chemotherapy. These results support the routine use of LUS by hepatic surgeons.

Validation of the IWATE criteria as a laparoscopic liver resection difficulty score in a single North American cohort.

BACKGROUND: Laparoscopic liver resection (LLR) involves a difficult learning curve, for which multiple difficulty scores have been proposed to assist with safe adaptation. The IWATE Criteria is a 4-level difficulty score shown to correlate with conversion to open surgery, estimated blood loss (EBL), and operative time in Japanese and French cohorts. We set out to validate the IWATE Criteria in a North American cohort, describe the evolution of our LLR program, and analyze the IWATE Criteria's ability to predict conversion to open surgery. METHODS: Patients that underwent LLR between January 2006 and December 2019 were selected from a prospectively maintained database. Difficulty outcomes, including conversion to open surgery, EBL, operative time, and post-operative complications were analyzed according to IWATE difficulty level, both overall and between chronological eras. The IWATE Criteria's ability to predict conversion to open surgery was assessed with a receiver operating characteristic (ROC) analysis. RESULTS: A total of 426 patients met inclusion criteria. Operative time, EBL, and conversion to open surgery increased in concordance with low to advanced IWATE difficulty. ROC analysis for conversion to open surgery demonstrated an overall area under the curve (AUC) of 0.694. Predictive performance was superior during the first two eras, with AUCs of 0.771 and 0.775; predictive value decreased as the LLR program gained experience, with AUCs of 0.708 and 0.551 for eras three and four. CONCLUSIONS: This study validated the IWATE Criteria in a North American population distinct from previous Japanese and French cohorts, based on its correlation with operative time, EBL, and conversion to open surgery. The IWATE Criteria may be of utility for identification of LLR cases appropriate for surgeon experience, as well as determination of laparoscopic feasibility. Interval difficulty score recalibration may be warranted as surgeon perception of difficulty evolves.

A chronological review of 500 minimally invasive liver resections in a North American institution: overcoming stagnation and toward consolidation.

BACKGROUND: Although interest in expanding the application of minimally invasive liver resection (MILR) is high the world over, most of the extensive experience in MILR has been reported from Far East Asia and Europe and its adoption in North America is limited. The aim of this study was to review the experience of MILR in a single North American institute over a 15-year period, highlighting both the obstacles encountered and strategies adopted to overcome the stagnation in its uptake. METHODS: This study included 500 MILR cases between 2006 and 2020. Patient demographics, disease characteristics, surgical technique, and perioperative outcomes are summarized. The major hepatectomy rate and conversion rate were assessed according to case numbers (first 100, 101-300, and 301-500 cases) to assess chronological trends. RESULTS: Of 500, 402 MILRs were done by pure laparoscopic (80.4%), 67 were hand assisted (13.4%), and 31 were robotic (6.2%). The majority (64%) of cases were performed for malignancy (n = 320; 100 Hepatocellular carcinoma, 153 Colorectal metastases, 27 Intrahepatic cholangiocarcinoma, and others, 40, 64%). A total of 71 cases were converted to open (14.2%). The annual case number gradually increased over the first few years; however, case numbers stayed around 30 between 2009 and 2017. In this period, despite accumulating MILR experience, open conversion rates increased despite no change in major hepatectomy rate. After this period of long-term stagnation, we introduced crucial changes in team composition and laparoscopic instrumentation. Our MILR case number and major hepatectomy rate thereafter increased significantly without increasing conversion or complication rates. CONCLUSION: Our recovery from long-term stagnation by instituting key changes as detailed in this study could be used as a guidepost for programs that are contemplating transitioning their MILR program from minor to advanced resections. Establishing a formal MILR training model through proper mentorship/proctorship and building a dedicated MILR team would be imperative to this strategy.