A dual-view multi-resolution laparoscope for safer and more efficient minimally invasive surgery.

Minimally invasive surgery (MIS) is limited in safety and efficiency by the hand-held nature and narrow fields of view of traditional laparoscopes. A multi-resolution foveated laparoscope (MRFL) was invented to address these concerns. The MRFL is a stationary dual-view imaging device with optical panning and zooming capabilities. It is designed to simultaneously capture and display a zoomed view and supplemental wide view of the surgical field. Optical zooming and panning capabilities facilitate repositioning of the zoomed view without physically moving the system. Additional MRFL features designed to improve safety and efficiency include its snub-nosed endoscope, tool-tip auto tracking, programmable focus profiles, unique selectable display modalities, foot pedal controls, and independently controlled surgeon and assistant displays. An MRFL prototype was constructed to demonstrate and test these features. Testing of the prototype validates its design architecture and confirms the functionality of its features. The current MRFL prototype functions adequately as a proof of concept, but the system features and performance require further improvement to be practical for clinical use.

High-throughput multi-resolution foveated laparoscope for minimally invasive surgery.

Feasibility and clinical utility of a multi-resolution foveated laparoscope (MRFL) was previously tested in a porcine surgical study. The study revealed several clinical limitations of the system including moisture proofing, working distance, image quality, low light performance, color accuracy, size, and weight. In this paper, we discuss the root causes of these limitations and strategies to correct them, present the design and prototyping of a new high throughput multi resolution foveated laparoscope (HT-MRFL), and demonstrate the HT-MRFL prototype performance in comparison to the MRFL and simulated performance metrics.

Surgeon Assessment of a Novel Multi-Resolution Foveated Laparoscope.

BACKGROUND: We developed a multi-resolution foveated laparoscope (MRFL) to improve situational awareness in laparoscopic surgery. We assessed surgeon objective task performance and subjective attitudes with MRFL when used for box trainer tasks and porcine surgery. METHODS: The MRFL simultaneously obtains a wide-angle view and a magnified view. The 2 images are displayed simultaneously. 6 urologists and 2 general surgeons performed box trainer and porcine surgery tasks with the MRFL and a standard laparoscope. Task time, use of display options, and subjective assessments were obtained. RESULTS: Subjectively, surgeons rated situational awareness, depth perception, and instrument interference as comparable between the prototype MRFL and laparoscope for trainer tasks. For porcine surgery, the MRFL was rated as having less interference than the standard laparoscope. The image quality of the MRFL was rated interior to the standard laparoscope. Participants found the different viewing modes useful for different roles and reported that they would likely use the MRFL for conventional laparoscopic and robotic surgery. Objectively, box trainer task time was comparable for 2 of 3 tasks with the remaining task shorter for the standard laparoscope. Porcine nephrectomy and oophorectomy were feasible with the prototype MRFL, although nephrectomy task time was significantly longer than traditional laparoscopy. CONCLUSIONS: The MRFL demonstrated feasibility for performing complex surgery. Surgeons had favorable attitudes toward its features and likelihood to use the device if available. Users utilized different view types for different tasks. Longer MRFL task times were attributed to poorer image quality of the prototype.

Improved multi-resolution foveated laparoscope with real-time digital transverse chromatic correction.

A multi-resolution foveated laparoscope (MRFL) with autofocus and zooming capabilities was previously designed to address the limiting trade-off between spatial resolution and field of view during laparoscopic minimally invasive surgery. The MRFL splits incoming light into two paths enabling simultaneous capture of the full surgical field and a zoomed-in view of the local surgical site. A fully functional prototype was constructed to demonstrate and test the autofocus, zooming capabilities, and clinical utility of this new laparoscope. The test of the prototype in both dry lab and animal models was successful, but it also revealed several major limitations of the prototype. In this paper, we present a brief overview of the aforementioned MRFL prototype design and results, and the shortcomings associated with its optical and mechanical designs. We then present several methods to address the shortcomings of the existing prototype with a modified optical layout and redesigned mechanics. The performances of the new and old system prototypes are comparatively analyzed in accordance with the design goals of the new MRFL. Finally, we present and demonstrate a real-time digital method for correcting transverse chromatic aberration to further improve the overall image quality, which can be adapted to future MRFL systems.

Association of adipose tissue and skeletal muscle metrics with overall survival and postoperative complications in soft tissue sarcoma patients: an opportunistic study using computed tomography.

BACKGROUND: To determine the relationship between adipose tissue and skeletal muscle measurements on computed tomography (CT) and overall survival and major postoperative complications in patients with soft-tissue sarcoma (STS). METHODS: The retrospective study included 137 STS patients (75 men, 62 women; mean age, 53 years, SD 17.7; mean BMI, 28.5, SD 6.6) who had abdominal CT exams. On a single CT image, at the L4 pedicle level, measurements of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and skeletal muscle area and attenuation were obtained using clinical PACS and specialized segmentation software. Clinical information was recorded, including STS characteristics (size, depth, grade, stage, and site), overall survival, and postoperative complications. The relationships between CT metrics and survival were analyzed using Cox proportional hazard models and those between CT metrics and postoperative complications using logistic regression models. RESULTS: There were 33 deaths and 41 major postoperative complications. Measured on clinical PACS, the psoas area (P=0.003), psoas index (P=0.006), psoas attenuation (P=0.011), and total muscle attenuation (P=0.023) were associated with overall survival. Using specialized software, psoas attenuation was also associated with overall survival (P=0.018). Adipose tissue metrics were not associated with survival or postoperative complications. CONCLUSIONS: In STS patients, CT-derived muscle size and attenuation are associated with overall survival. These prognostic biomarkers can be obtained using specialized segmentation software or routine clinical PACS.

Conservative management of desmoid tumors is safe and effective.

BACKGROUND: Surgical resection of desmoid tumors has traditionally been the mainstay of therapy, but this is a potentially morbid approach with high rates of recurrence. Given increasing reports of active surveillance in this disease, we sought to evaluate our experience with conservative management hypothesizing this would be an effective strategy. MATERIALS AND METHODS: Using a prospectively maintained database of sarcoma patients from 2008 to 2015, we identified 47 patients with a diagnosis of desmoid tumor from all anatomic sites. Data points were abstracted on clinical and pathologic factors, disease stability or progression, and follow-up time. Main outcome measurements were tumor recurrence after surgical resection versus tumor progression with conservative management. RESULTS: In our cohort, 20 patients were managed with surveillance, 24 patients with surgery, and three patients with other approaches. Clinical and tumor characteristics between treatment groups were not significantly different. With a median follow-up of 35.7 mo, there was one complete regression, five partial regressions, and 13 stable diseases among the surveillance group. Only one patient under observation progressed, crossing over to surgical resection. Among 24 patients managed with surgery, 13 patients developed local recurrence. Kaplan-Meier analysis revealed a statistically superior progression-free survival in the surveillance group (P = 0.001). CONCLUSIONS: This retrospective analysis adds to the growing body of evidence that observation of desmoid tumors is safe and effective with high rates of stable disease. These data further support an initial conservative approach to desmoid tumors that may spare patients the morbidity and risk of recurrence that accompanies potentially extensive operations.

Splenic artery embolization: a single center experience on the safety, efficacy, and clinical outcomes.

PURPOSE: We aimed to assess the safety, efficacy, and clinical outcomes of splenic artery embolization (SAE). MATERIALS AND METHODS: A total of 50 patients (male:female, 33:17; mean age, 49 years) who underwent 50 SAEs between 1998 and 2011 were retrospectively studied. The procedure indications included aneurysm or pseudoaneurysm (n=15), gastric variceal hemorrhage (n=15), preoperative reduction of surgical blood loss (n=9), or other (n=11). In total, 22 procedures were elective, and 28 procedures were urgent or emergent. The embolic agents included coils (n=50), gelatin sponges (n=15), and particles (n=4). The measured outcomes were the technical success of the procedure, efficacy, side effects, and the 30-day morbidity and mortality rates. RESULTS: All embolizations were technically successful. The procedure efficacy was 90%; five patients (10%) had a recurrent hemorrhage requiring a secondary intervention. Side effects included hydrothorax (n=26, 52%), thrombocytosis (n=16, 32%), thrombocytopenia (n=13, 26%), and postembolization syndrome (n=11, 22%). Splenic infarcts occurred in 13 patients (26%). The overall and procedure-specific 30-day morbidity rates were 38% (19/50) and 14% (splenoportal thrombosis, 3/50; encapsulated bacterial infection, 1/50; splenic abscess, 1/50; femoral hematoma requiring surgery, 1/50; hydrothorax requiring drainage, 1/50). The overall and procedure-specific 30-day mortality rates were 8% (4/50) and 0%. The multivariate analysis showed that advanced patient age (P = 0.037), postprocedure thrombocytopenia (P = 0.008), postprocedure hydrothorax (P = 0.009), and the need for a secondary intervention (P = 0.004) predicted the 30-day morbidity, while renal insufficiency (P < 0.0001), preprocedure hemodynamic instability (P = 0.044), and preprocedure leukocytosis (P < 0.0001) were prognostic factors for the 30-day mortality. CONCLUSION: SAE was performed with high technical success and efficacy, but the outcomes showed nontrivial morbidity rates. Elderly patients with thrombocytopenia and hydrothorax after SAE, and patients who require secondary interventions, should be monitored for complications.

Subcutaneous plasmacytoma metastasis precipitated by tunneled central venous catheter insertion.

Extramedullary plasmacytomas are tumors of monoclonal plasma cells arising within soft tissue that uncommonly occur in multiple myeloma patients. While sporadic development of these tumors at cutaneous trauma sites, including venous catheter access sites, has been reported, interventional radiologists seldom encounter this disease. Herein, we describe a case of metastatic subcutaneous plasmacytoma precipitated by tunneled central venous catheter insertion in a male patient undergoing stem cell therapy for treatment of multiple myeloma. In addition, we review the identification, diagnostic pitfalls, pathogenesis, and treatment of this rare entity.

Endovascular treatment of intimomedial mucoid degeneration.

Intimomedial degeneration is a rare and poorly understood vascular disorder involving the circumferential deposition of large amounts of mucoid material within the intima and media of the arterial wall, causing weakening that results in aneurysm formation of the involved segment. The cause of the disease is unknown at this time. The authors describe the endovascular treatment of a large symptomatic superior gluteal artery aneurysm in a patient with multiple arterial aneurysms and the histologic diagnosis of intimomedial mucoid degeneration. In addition, they perform a review of the literature on this unusual vasculopathy.

A highly sensitive ELISA D-dimer increases testing but not diagnosis of pulmonary embolism.

OBJECTIVES: To determine the effect of introducing a rapid enzyme-linked immunosorbent assay (ELISA) D-dimer on the percentage of emergency department (ED) patients evaluated for pulmonary embolism (PE), the use of associated laboratory testing, pulmonary vascular imaging, and the diagnoses of PE. METHODS: Patients evaluated for PE during three 120-day periods were enrolled: immediately before (period 1), immediately after (period 2), and one year after the introduction of a rapid ELISA D-dimer in the hospital. The frequency of ED patients evaluated for PE with any test, with D-dimer testing, and with pulmonary vascular imaging and the frequency of PE diagnosis during each time period were determined. RESULTS: The percentage of patients evaluated for PE nearly doubled; from 1.36% (328/24,101) in period 1 to 2.58% (654/25,318) in period 2 and 2.42% (583/24,093) in period 3. The percentage of patients who underwent D-dimer testing increased more than fourfold; from 0.39% (93/24,101) in period 1 to 1.83% (464/25,318) in period 2 and 1.77% (427/24,093) in period 3. The percentage of patients who underwent pulmonary vascular imaging increased from 1.02% (247/24,101) in period 1 to 1.36% (344/25,318) in period 2 and to 1.39% (334/24,093) in period 3. There was no difference in the percentage of patients diagnosed as having PE in period 1 (0.20% [47/24,101]), period 2 (0.27% [69/25,318]), and period 3 (0.24% [58/24,093]). CONCLUSIONS: In the study's academic ED, introduction of ELISA D-dimer testing was accompanied by an increase in PE evaluations, D-dimer testing, and pulmonary vascular imaging; there was no observed change in the rate of PE diagnosis.

From annotated genomes to metabolic flux models and kinetic parameter fitting.

Significant advances in system-level modeling of cellular behavior can be achieved based on constraints derived from genomic information and on optimality hypotheses. For steady-state models of metabolic networks, mass conservation and reaction stoichiometry impose linear constraints on metabolic fluxes. Different objectives, such as maximization of growth rate or minimization of flux distance from a reference state, can be tested in different organisms and conditions. In particular, we have suggested that the metabolic properties of mutant bacterial strains are best described by an algorithm that performs a minimization of metabolic adjustment (MOMA) upon gene deletion. The increasing availability of many annotated genomes paves the way for a systematic application of these flux balance methods to a large variety of organisms. However, such a high throughput goal crucially depends on our capacity to build metabolic flux models in a fully automated fashion. Here we describe a pipeline for generating models from annotated genomes and discuss the current obstacles to full automation. In addition, we propose a framework for the integration of flux modeling results and high throughput proteomic data, which can potentially help in the inference of whole-cell kinetic parameters.