Designing a Private and Secure Personal Health Records Access Management System: A Solution Based on IOTA Distributed Ledger Technology.

The privacy and security of patients' health records have been an ongoing issue, and researchers are in a race against technology to design a system that can help stop the compromising of patient data. Many researchers have proposed solutions; however, most solutions have not incorporated potential parameters that can ensure private and secure personal health records management, which is the focus of this study. To design and develop a solution, this research thoroughly investigated existing solutions and identified potential key contexts. These include IOTA Tangle, Distributed Ledger Technology (DLT), IPFS protocols, Application Programming Interface (API), Proxy Re-encryption (PRE), and access control, which are analysed and integrated to secure patient medical records, and Internet of Things (IoT) medical devices, to develop a patient-based access management system that gives patients full control of their health records. This research developed four prototype applications to demonstrate the proposed solution: the web appointment application, the patient application, the doctor application, and the remote medical IoT device application. The results indicate that the proposed framework can improve healthcare services by providing immutable, secure, scalable, trusted, self-managed, and traceable patient health records while giving patients full control of their own medical records.

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.

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.

Comparison of Parathyroid Autofluorescence Signals in Different Types of Hyperparathyroidism.

BACKGROUND: There are scant data in the literature regarding whether parathyroid autofluorescence (AF) signal patterns vary based on the etiology of hyperparathyroidism. The aim of this study was to compare AF signals of parathyroid glands across different etiologies of hyperparathyroidism. METHODS: As a prospective institutional review board-approved study between 2016 and 2019, AF intensities and heterogeneity indexes (HIs) of parathyroid glands in patients who underwent parathyroidectomy using AF were calculated and compared using Chi-square, Kruskal Wallis, Mann Whitney U, and logistic regression tests. RESULTS: Of the total of 183 patients, 127 patients had sporadic classic primary hyperparathyroidism, 30 patients had sporadic normohormonal primary hyperparathyroidism, 10 patients had sporadic normocalcemic primary hyperparathyroidism, 12 patients had tertiary hyperparathyroidism, and 4 patients had familial primary hyperparathyroidism related to multiple endocrine neoplasia (MEN) 2A. There were no statistical differences in AF signals of abnormal parathyroid glands in classic, normohormonal or normocalcemic sporadic hyperparathyroidism. Parathyroid glands in patients with tertiary hyperparathyroidism were similar in intensity, but more homogenous compared to those in sporadic primary hyperparathyroidism. CONCLUSIONS: The pattern of AF exhibited by abnormal parathyroid glands was similar across different spectrums of primary hyperparathyroidism, in accordance with observations in the literature. However, parathyroid glands in tertiary hyperparathyroidism were more homogeneous, despite exhibiting a similar intensity of AF compared to those in sporadic primary hyperparathyroidism. These differences should be kept in mind when using the AF pattern as an adjunct to visual assessment in parathyroid exploration.

Addressing the Challenges of Electronic Health Records Using Blockchain and IPFS.

Electronic Health Records (EHR) are the healthcare sector's core digital strategy meant to improve the quality of care provided to patients. Despite the benefits afforded by this digital transformation initiative, adoption among healthcare organizations has been slower than desired. The sheer volume and sensitive nature of patient records compel these organizations to exercise a healthy amount of caution in implementing EHR. Cyberattacks have also increased the risks associated with non-optimal EHR implementations. An influx of high-profile data breaches has plagued the sector during the COVID-19 pandemic, which put the spotlight on EHR cybersecurity. One objective of this research project is to aid the acceleration of EHR adoption. Another objective is to ensure the robustness of the system to resist malicious attacks. For the former, a systematic review was used to unearth all the possible causes why the adoption of EHR has been anemic. In this paper, sixty-five existing proposed EHR solutions were analyzed and it was found that there are fourteen major challenges that need to be addressed to reduce friction and risk for health organizations. These were privacy, security, confidentiality, interoperability, access control, scalability, authentication, accessibility, availability, data storage, data ownership, data validity, data integrity, and ease of use. We propose EHRChain, a new framework that tackles all the listed challenges simultaneously to address the first objective while also being designed to achieve the second objective. It is enabled by dual-blockchains based on Hyperledger Sawtooth to allow patient data decentralization via a consortium blockchain and IPFS for distributed data storage.

Robotic Posterior Retroperitoneal Adrenalectomy: Patient Selection and Long-Term Outcomes.

BACKGROUND: Recently, efficacy of laparoscopic posterior retroperitoneal adrenalectomy (PRA) for pheochromocytoma and malignancy has been questioned. Although robotic technique using wristed instruments may improve limitations of laparoscopic PRA, the worldwide experience with robotic PRA is limited. This study aimed to describe patient characteristics, surgical technique, and long-term outcomes of robotic PRA from a 12-year single-center experience. METHODS: This analysis was an institutional review board-approved retrospective study. In this study, PRA was performed robotically, with intraoperative ultrasound and indocyanine green imaging guidance. Long-term outcomes and predictors of operative time (OT) were assessed using descriptive and regression analyses. Using OT as a surrogate for difficulty of procedure, receiver operating characteristic curve analysis was performed to quantify anthropometric thresholds that would predict a more challenging procedure. RESULTS: Altogether, 112 robotic PRA procedures were performed. Three cases (3%) were converted to a lateral approach, and one case (1%) was converted to open surgery. The morbidity rate was 2%. Microscopic capsular disruption occurred for one patient. No patient experienced persistent disease or local recurrence from pheochromocytoma or malignant adrenal tumors during the follow-up period (median, 48 months). Operating time was independently predicted by perirenal fat thickness, with 18.5 mm as the critical threshold. CONCLUSION: In this study, favorable PRA outcomes were achieved with careful patient selection and meticulous surgical technique that used robotic articulation guided by intraoperative imaging.

A Critical Analysis of Computed Tomography Washout in Lipid-Poor Adrenal Incidentalomas.

BACKGROUND: Contrast-enhanced computed tomography (CT) with washout has emerged as an option to distinguish lipid-poor adenomas from non-adenomas. OBJECTIVE: The aim of this study was to assess the utility of CT washout in characterizing indeterminate lipid-poor adrenal incidentalomas. METHODS: From an Institutional Review Board-approved database, patients with adrenal incidentalomas who had adrenal protocol CT scans with a 15-min washout between 2003 and 2019 were identified. Non-contrast CT attenuation and washout patterns of different tumor types were compared. RESULTS: Overall, 156 patients with 175 adrenal lesions were included. Average tumor size was 3.0 cm, non-contrast CT density was 24.7 Hounsfield units (HU), and absolute washout was 52.6%. In 102 lesions (58.3%), CT washout was ≥ 60%; 94 (92.2%) of these were benign adrenocortical adenomas, 7 (6.9%) were pheochromocytomas, and 1 (0.9%) was an adrenal hematoma. Furthermore, in 73 tumors (41.7%), CT washout was < 60%; diagnosis was benign adrenocortical adenoma in 45 (61.6%) lesions, pheochromocytoma in 8 (11%) lesions, metastasis in 9 (12.3%) lesions, adrenocortical cancer in 6 (8.2%) lesions, and 'others' in 5 (6.9%) lesions. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of  > 60% absolute CT washout for detecting an adrenal adenoma was 67.6%, 77.8%, 92.2%, 38.4%, and 69.7%, respectively. CONCLUSION: CT washout should be incorporated into the management algorithm of indeterminate adrenal incidentalomas with a high non-contrast CT attenuation to 'rule-in' benign tumors. For small tumors with mild elevation of plasma metanephrines, it should be kept in mind that adenomas and pheochromocytomas may have similar imaging and washout characteristics.

Can near-infrared autofluorescence imaging be used for intraoperative confirmation of parathyroid tissue?

BACKGROUND AND OBJECTIVES: Whether ex vivo autofluorescence (AF) imaging findings could be quantified to intraoperatively differentiate parathyroid tissue has not been reported. Our aim was to assess the ability of AF imaging to confirm parathyroid tissue during thyroidectomy and parathyroidectomy procedures. METHODS: This was a retrospective Institutional Review Board-approved study. AF signals of specimens imaged ex vivo before submission to pathology during thyroidectomy and parathyroidectomy procedures were quantified. Using receiver operating characteristic (ROC) curves, optimal values for sensitivity/specificity to differentiate parathyroid tissue were calculated. RESULTS: 166 parathyroid and 217 non-parathyroid specimens were analyzed. With surgical drapes as background, the optimal normalized AF intensity threshold to predict parathyroid tissue on ROC curve analysis was 1.72 (86.1% sensitivity, 84.8% specificity, and area under the curve [AUC]: 0.919). The cutoff for 97% sensitivity was 1.31 and for 99.1% specificity was 3.16. With Telfa as background, the optimal threshold to predict parathyroid tissue was 1.46 (88.4% sensitivity, 76.8% specificity, and AUC: 0.896). The threshold for 96.8% sensitivity was 1.18 and for 98.8% specificity was 2.44. If thresholds for highest specificity were used, 40% of frozen sections to confirm parathyroid tissue could have been avoided. CONCLUSION: Quantified brightness analysis of ex vivo AF signals may have utility in intraoperative differentiation of parathyroid tissue for 40% of surgical specimens.

Impact of ablation algorithm versus tumor-dependent parameters on local control after microwave ablation of malignant liver tumors.

BACKGROUND: The aim of this study is to assess the effect of tumor versus ablation-algorithm dependent parameters on local recurrence (LR) after microwave ablation (MWA) of liver malignancies. METHODS: This was an institutional review board-approved study of patients who underwent laparoscopic or open MWA of malignant liver tumors. The impact of ablation algorithm (stepwise or direct heating, single or overlapping ablations, and ablation margin) and tumor-dependent (type, size, location, and blood vessel proximity) parameters on LR was analyzed using Kaplan-Meier and Cox proportional hazards. RESULTS: A total of 179 patients with 602 liver tumors underwent 200 MWA procedures. Colorectal liver metastasis (CLM) was the most frequent tumor type followed by neuroendocrine liver metastasis (NELM), other metastatic tumors, and hepatocellular cancer (HCC). For patients followed at least a year with imaging, LR rate was 8.8% per lesion and 13.1%,1.3%, 11.7%, and 12.6%, for CLM, NELM, HCC, and other tumor types, respectively. On multivariate analysis, independent predictors of LR included tumor type, tumor size, and ablation margin. CONCLUSION: LR after MWA for malignant liver tumors is predicted by both tumor and surgeon-dependent factors. Variations in the ablation algorithm did not affect LR, leaving the ablation margin as the only parameter that could be modified to optimize local tumor control.

Intraoperative near-infrared imaging of parathyroid glands: A comparison of first- and second-generation technologies.

BACKGROUND: Intraoperative near-infrared imaging (NIFI) of parathyroid glands (PG) by first-generation technology had limited image quality and depth penetration. Second-generation NIFI has recently been introduced. Our aim was to compare (1) capability to detect PG and (2) image quality between older and newer technologies. METHODS: Accurately detecting PG, as well as, quality of autofluorescence (AF) was compared between an older charge-coupled device (CCD) camera and a newer complementary metal-oxide semiconductor (CMOS). χ2 , t test, and analysis of variance were used for analysis. RESULTS: There were 300 patients who underwent parathyroidectomy (PTX) and/or thyroidectomy (THY) with NIFI, 200 with CCD, and 100 with CMOS. Although both NIFI technologies detected >94% of PG, CMOS was superior to CCD. Comparing AF quality, mean pixel intensity of PG compared with the background was higher with CMOS compared with CCD. When comparing PG detected by NIFI before visual identification by a surgeon, both CCD and CMOS had similar results (25% vs. 22%; p = .3). CONCLUSION: Both NIFI cameras were excellent at detecting PG. Second-generation NIFI (CMOS) displayed higher detection rates and AF intensity. Although surgeons identified majority of PG before NIFI detection, 25% of PG were identified with NIFI first, suggesting future advancements of this technology may expand its applications during parathyroid/thyroid operations.

Compact and modular autonomous surface vehicle for water research: The Naval Operating Research Drone Assessing Climate Change (NORDACC).

Research, monitoring, and management of marine and aquatic ecosystems often require surface water samples to measure biogeochemical and optical parameters. Traditional sampling with a boat and several personnel onboard can be labor-intensive and safety requirements limit sampling activities in high-risk environments. This paper describes the Naval Operating Research Drone Assessing Climate Change (NORDACC). NORDACC is an open source, light-weight, and portable autonomous surface vehicle that can acquire surface water samples while also measuring sea surface temperature and salinity for the duration of its deployment. NORDACC is ideal for operations in remote areas where resources and personnel are limited. Two sample bottles, each one liter in volume, can be filled, either at pre-programmed sampling stations or manually, using the remote control. A trimaran design provides buoyancy and stability, with hulls constructed of vacuum-formed acrylonitrile butadiene styrene (ABS) plastic. NORDACC can navigate autonomously between waypoints and features first person view capabilities for enhanced situational awareness. NORDACC's performance was validated in Aarhus Bay, Denmark, collecting multiple surface water samples in winds in excess of 8 ms-1 and steep, choppy waves.

Can CT Pelvimetry Be Used to Predict Circumferential Resection Margin Positivity in Laparoscopic Resection of Middle and Lower Rectum Cancer?

Background Previous studies have shown that pelvimetry can be valuable in predicting surgical difficulties in rectal cancer operations. However, its usability in predicting circumferential resection margin (CRM) involvement remains debatable. This study investigated the factors affecting CRM status and the importance of computed tomography (CT) pelvimetry in predicting CRM involvement in laparoscopic resection of middle and lower rectal cancer. Methodology In this study, we retrospectively investigated the data of 111 patients who underwent a laparoscopic operation for middle and lower rectum cancer at Ankara University Faculty of Medicine, Department of Surgical Oncology between January 2014 and January 2020. The predictive value of CT pelvimetry and other variables on the CRM status was analyzed. Results The following four pelvic parameters differed significantly between the genders: transverse diameter of the pelvic inlet (p = 0.024), anteroposterior diameter of the pelvic outlet (p = 0.003), transverse diameter of the pelvic outlet (p < 0.001), and pelvic depth (p < 0.001). The effect of pelvic anatomic parameters on CRM involvement was not found to be significant. It was found that tumor height from the anal verge (p = 0.004), tumor size (p < 0.001), and gender (p = 0.033) were significant risk factors for CRM involvement. Survival was poor in patients with male gender (p = 0.032), perineural invasion (p < 0.001), and grade 3 tumor. Conclusions In this study, no benefit was found in predicting CRM positivity from CT pelvimetry in the laparoscopic resection of middle and lower rectal cancer. Besides, tumor height from the anal verge, tumor size, and gender were important factors for CRM positivity. Although our study sheds light on this issue, prospective randomized studies with larger sample sizes are needed.

Management of Aberrant Left Hepatic Artery During Laparoscopic Gastrectomy and Consequences.

Introduction: Aberrant left hepatic artery (ALHA) can exist in up to 25% of the population. The presence of ALHA during lymph node (LN) dissection in gastric cancer may complicate the process. In this study, we aimed to evaluate the existence rate, management, and consequences of ALHA in our laparoscopic gastrectomy series. Patients and Methods: Demographical and clinical data of laparoscopically operated 158 consecutive gastric cancer patients were collected retrospectively. Study patients were divided into three groups according to absence, existence and preservation, and existence and sacrification of ALHA. Harvested LN numbers, operation time, and postoperative alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase values on consecutive days were analyzed using Kruskal-Wallis and Mann-Whitney U tests. P < .05 is accepted as significant. Results: The median AST and ALT values of the ALHA-sacrificed group were higher than those of the group without ALHA and the ALHA-preserved group on the 1st, 3rd, and 5th postoperative days (P < .05). On the 10th day, liver enzymes returned to normal values. Conclusion: Adequate and appropriate dissection of LNs while preserving ALHA can be performed without prolonging the operation time. Sacrification of ALHA causes an increase in liver enzymes, with spontaneous recovery in most cases.

Development of an algorithm for intraoperative autofluorescence assessment of parathyroid glands in primary hyperparathyroidism using artificial intelligence.

BACKGROUND: Previous work showed that normal and abnormal parathyroid glands exhibit different patterns of autofluorescence, with the former appearing brighter and more homogenous. However, an objective algorithm based on quantified measurements was not provided. The aim of this study is to develop objective algorithms for intraoperative autofluorescence assessment of parathyroid glands in primary hyperparathyroidism using artificial intelligence. METHODS: The utility of near-infrared fluorescence imaging in parathyroidectomy procedures was evaluated in a study approved by the institutional review board. Autofluorescence patterns of parathyroid glands were measured intraoperatively. Comparisons were performed between normal and abnormal glands, as well as between different pathologies. Using machine learning, decision trees were created. RESULTS: Normal parathyroid glands were brighter (higher normalized autofluorescence pixel intensity) and more homogenous (lower heterogeneity index) compared to abnormal glands. Optimal cutoffs to differentiate normal from abnormal parathyroid glands were >2.0 for normalized autofluorescence intensity (sensitivity 73%, specificity 70%, area under the curve 0.756) and <0.12 for parathyroid heterogeneity index (sensitivity 75%, specificity 81%, area under the curve 0.839). Decision trees created by machine learning using normalized autofluorescence intensity, heterogeneity index, and gland volume were 95% accurate in predicting normal versus abnormal glands and 84% accurate in predicting subclasses of parathyroid pathologies. CONCLUSION: To our knowledge, this is the first study to date reporting objective algorithms using quantified autofluorescence data to intraoperatively assess parathyroid glands in primary hyperparathyroidism. These results suggest that objective data can be obtained from autofluorescence signals to help differentiate abnormal parathyroid glands from normal glands.

An intra-operative video comparison of laparoscopic versus robotic transabdominal lateral adrenalectomy.

BACKGROUND: The aim was to compare intraoperative conduct of adrenalectomy between laparoscopic and robotic approaches. METHODS: Intraoperative video-recordings of patients who underwent robotic (n = 30) and laparoscopic adrenalectomy (n = 30) were analysed using Mann-Whitney U, chi-square and multivariate regression analyses. RESULTS: Demographics, indications and outcomes were similar between groups. For all tumour sizes, camera was more engaged to surgical task and exhibited less vision problems in robotic versus laparoscopic group. There was less instrument exchange and restriction of exposure with robotic approach. For dissection, robotic approach allowed for a wider range of instrument reach around adrenal. Robotically, there was an increased ability to do fine dissection, rather than en bloc division with rigid laparoscopic vessel sealers. Bleeding problems were less robotically. CONCLUSION: Despite similarities in post-operative morbidity and hospital stay, there was a superiority in quality of procedure performed with robotic versus laparoscopic adrenalectomy for both small and large adrenal tumours.

The effect and clinical significance of using nathanson liver retractor on liver function tests in laparoscopic gastric cancer surgery.

AIM: There are very few studies in the literature investigating the changes caused by the Nathanson retractors in liver function tests (LFT) after LG and its clinical significance. The present study investigated the changes made by the Nathanson retractor used during LG on LFT and its clinical significance. MATERIAL AND METHOD: The data of 236 patients, who underwent radical gastrectomy for primary gastric cancer at Surgical Oncology Unit in the period between January 2015 and January 2020 were retrospective studied. The patients were divided into two groups: laparoscopic gastrectomy (LG; 136 cases) and open gastrectomy (OG; 106 cases). Patients who have undergone cholecystectomy, with primary or secondary liver tumors, with chronic hepatic disease, who have preoperative high ALT, AST and bilirubin values were excluded from the study. LFT were measured preoperatively and postoperative day 1 (LFT1), LFT3, LFT5 and LFT7. LFT: ALT, AST and Total bilirubin (BIL). RESULTS: ALT1, ALT3, ALT5, ALT7 ALT values and AST1, AST3, AST5 AST values of the patients in the LG group were found to be significantly higher (P <0.001). Mean total bilirubin values of the groups were similar (P >0.05). In order to evaluate how the increase in LFT due to the use of the Nathanson retractors reflected on the patients' clinic, we divided the patients who underwent LG into two groups based on ALT increase in ALT1: Normal and Elevated. The in-hospital mortality rates (P = 0.080) and oral nutrition time (P = 0.913) of the groups were similar. No liver infarction developed in any of the groups. The duration of stay in the ICU was significantly longer in individuals with elevated LFT (P = 0.019). CONCLUSION: Although the use of the Nathanson retractor during LG causes an increase in liver function tests, this does not cause major clinical problems in patients. Key Words: Gastrectomy; gastric cancer; laparoscopy; liver enzymes; liver dysfunciton.

Standardization of thyroid fine needle aspiration procedure and outcomes within an endocrine surgery department.

BACKGROUND: Fine needle aspiration (FNA) biopsy is an essential procedure for thyroid nodules. Although, the efficacy of surgeon-performed thyroid FNA biopsies has been demonstrated in the literature, there are insufficient data regarding how to establish an efficient program with a low insufficiency rate within a group practice. METHODS: An endocrine surgery thyroid FNA biopsy program was established in 2000 by one surgeon, with training of additional partners during fellowship and upon recruitment. The results within 18 years were analyzed. The FNA biopsies were performed by endocrine surgeons under ultrasound guidance without on-site pathologist review. RESULTS: A total of 5,469 FNA biopsies were performed by 7 surgeons. The total number of FNA biopsies performed by each surgeon varied between 291-1,378. FNA biopsies were performed in 2 passes using 22-gauge needles under constant suction. The overall insufficiency rate was 4.3%, with individual surgeon rates ranging between 2.7% and 7.2%. The insufficiency rate for the whole team ranged between 3.3% and 5% when examined in 5-year blocks. CONCLUSIONS: This study shows that an establishment of a highly efficient thyroid FNA biopsy program within a group practice is possible with a structured endocrine surgical training and adoption of a standard technique.

An Analysis of Free-hand Targeting in Laparoscopic Liver Microwave Ablation.

BACKGROUND: Recently, new technologies have been developed for antenna placement in laparoscopic liver tumor ablation (LLTA). At this point, it is important to analyze the efficacy of free-hand targeting to identify deficiencies and opportunities for improvement. METHODS: This was an institutional review board-approved retrospective study. Video recordings of 30 consecutive patients with 77 lesions who underwent LLTA were reviewed. Tumor-specific anatomic and targeting-related parameters were analyzed using χ2, t test, and regression analyses. RESULTS: Neuroendocrine metastasis was the dominant tumor type, with median tumor size 1.4 cm (range, 0.5 to 5.2). In total, 41 (53%) tumors were superficial and 36 (47%) deep. In 68 lesions (88%), an optimal targeting was achieved with first attempt, without a need for repositioning; whereas 9 lesions (12%) required repositioning of antenna. For 37% (15/41) of superficial and 56% (20/36) of deep lesions, a straight avascular needle trajectory was not present, requiring steering of the antenna around vascular and biliary structures. All procedures were completed laparoscopically without bleeding or biliary complications. Local treatment recurrence rate in follow-up was 10% (n=8). CONCLUSIONS: This study shows that in experienced hands, LLTA through free-hand technique is safe and efficacious, providing an accurate targeting with the first pass in 90% of tumors. Although newer technology is being developed to guide less-experienced surgeons in needle targeting, it should be kept in mind that a straight trajectory is not available for 1/3 of superficial and half of deep lesions. Hence, ablation surgeons need to develop free-hand skills to avoid possible hemorrhagic and biliary complications in LLTA.