The article comprises three main parts: a historical review on navigation, the mathematical basics for calculation and the clinical applications of navigation devices. Main historical steps are described from the first idea till the realisation of the frame-based and frameless navigation devices including robots. In particular the idea of robots can be traced back to the Iliad of Homer, the first testimony of European literature over 2500 years ago. In the second part the mathematical calculation of the mapping between the navigation and the image space is demonstrated, including different registration modalities and error estimations. The error of the navigation has to be divided into the technical error of the device calculating its own position in space, the registration error due to inaccuracies in the calculation of the transformation matrix between the navigation and the image space, and the application error caused additionally by anatomical shift of the brain structures during operation. In the third part the main clinical fields of application in modern neurosurgery are demonstrated, such as localisation of small intracranial lesions, skull-base surgery, intracerebral biopsies, intracranial endoscopy, functional neurosurgery and spinal navigation. At the end of the article some possible objections to navigation-aided surgery are discussed.

Frame-based stereotactic biopsies are time-consuming procedures making necessary head fixation in a ring, explicit coordinate calculation and setting of the parameters. Frameless systems make many of these intermediate steps unnecessary, impose less mechanical restrictions regarding access to the lesions, and with slight modifications can be used to perform stereotactic biopsies. A special adaptation designed to fix the holder and the biopsy instrument is described. The neuronavigation optical tracking system of Radionics was used. CT scans were performed with 6 skin markers. Calibration was performed after head fixation in the Mayfield clamp. Mean calibration error was 2.19 +/- 0.81 mm. The light-emitting diode holder of the pointer was fixed into 2 Leila arms and moved under visual control based on CT images. The target point was selected, Leila arms fixed and a burr hole performed. The cannula was introduced to the target, being fitted with a depth stop in a length identical to that of the pointer on the screen. If necessary a second trajectory was easily selected. 49 patients underwent a frameless stereotactic biopsy. All targets except seven were superficial or in the white matter. In selected cases the biopsies were taken from deep-seated lesions. A histological diagnosis was obtained in 100 % of the cases. Four cases deteriorated postoperatively, two of these related to intratumoral bleeding. Navigation is a simple and effective method to perform biopsies of superficial and relatively large lesions. Frame-based procedures are restricted to brainstem tumors and lesions less than 1.5 cm in diameter.

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Background: Intrahepatic cholangiocarcinoma (IHC) is a malignancy with an increasing incidence. Surgery is the only treatment modality associated with long term survival. The objective of this study is to utilize a nationwide representative database to quantify the trends in incidence, and surgery for IHC in the United States from 2004-2014, as well as identify any disparities in the receipt of surgery. Methods: All patients admitted with a diagnosis of IHC between 2005 and 2014 were identified from the Nationwide Inpatient Sample (NIS) database. Trends in the number of IHC admissions and surgery procedures as well as outcomes were examined, and a multivariate analysis was used to determine the effects of demographic and clinical co-variables on resection rates.

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Diversity in a physician workforce is essential to effectively treat a rapidly changing patient population and optimize the modern healthcare environment. Physicians must be culturally competent and integrate a diversity of language, communication styles, beliefs, and attitudes into patient care. 1 Delivery of equitable health care depends on a diverse physician workforce, which has been proven to result in improved patient satisfaction and quality of care, 2 as well as superior financial performance for health systems. 3 Outside of health care, diversity leads to improved company culture, talent retention, and increased innovation. 4 Innovative solutions and adaptability are essential in the face of major shifts in healthcare paradigms, such as those unfolding during the Coronavirus Disease 2019 pandemic, and will absolutely require a diverse physician workforce.Despite evidence in favor of a diverse workforce, diversity among physicians remains low, particularly in surgical subspecialties. Among academic cardiothoracic (CT) surgeons in 2018, Black and Hispanic surgeons composed only 3% and 5% of the workforce, respectively, despite representing 13% and 18% of the general US population. 5 Women represented only 17% of practicing CT surgeons. Representation of these groups is even lower among senior and leadership positions. 6 Furthermore, trainees and surgeons have reported high rates of racial discrimination,

HighlightsFibrolamellar hepatocellular carcinoma is a rare form of hepatocellullar cancer seen in younger patients without underlying liver disease.Liver resection with lymph node dissection is the mainstay of treatment.Bile duct tumor thrombus that has been reported in hepatocellular cancer has to date never been described in fibrolamellar hepatocellular cancer and must be a consideration in patients who present with obstructive jaundice.

A 50-year-old female with no significant medical history initially presented to an urgent care center with symptoms of acute onset abdominal pain, nausea, and emesis. Chest and abdominal X-ray revealed free air under the diaphragm, prompting immediate transfer to the emergency department. Continued abdominal tenderness and pain were concerning for perforated viscus. The patient was transferred to the operating room, and diagnostic laparoscopy was performed. Inflammation and contamination were discovered in the right side of the abdomen and pelvis secondary to a small bowel (SB) perforation. Segmental SB resection revealed a perforated diverticulum. Pathological examination confirmed a diagnosis of gastrointestinal stromal tumor (GIST) at the perforated segment. On postoperative day 5, the patient was discharged home, and at 30-month follow-up, the patient continued to do well. Although rare, SB diverticula are commonly false (i.e., pseudodiverticula). The concomitant presence of a GIST in a true SB diverticulum presenting with perforation has not yet been reported.