3D-printed haptic "reverse" models for preoperative planning in soft tissue reconstruction: a case report.

In reconstructive surgery, preoperative planning is essential for optimal functional and aesthetic outcome. Creating a three-dimensional (3D) model from two-dimensional (2D) imaging data by rapid prototyping has been used in industrial design for decades but has only recently been introduced for medical application. 3D printing is one such technique that is fast, convenient, and relatively affordable. In this report, we present a case in which a reproducible method for producing a 3D-printed "reverse model" representing a skin wound defect was used for flap design and harvesting. This comprised a 82-year-old man with an exposed ankle prosthesis after serial soft tissue debridements for wound infection. Soft tissue coverage and dead-space filling were planned with a composite radial forearm free flap (RFFF). Computed tomographic angiography (CTA) of the donor site (left forearm), recipient site (right ankle), and the left ankle was performed. 2D data from the CTA was 3D-reconstructed using computer software, with a 3D image of the left ankle used as a "control." A 3D model was created by superimposing the left and right ankle images, to create a "reverse image" of the defect, and printed using a 3D printer. The RFFF was thus planned and executed effectively, without complication. To our knowledge, this is the first report of a mechanism of calculating a soft tissue wound defect and producing a 3D model that may be useful for surgical planning. 3D printing and particularly "reverse" modeling may be versatile options in reconstructive planning, and have the potential for broad application.

Four-Dimensional (4D) Printing: A New Evolution in Computed Tomography-Guided Stereolithographic Modeling. Principles and Application.

BACKGROUND: Over the last decade, image-guided production of three-dimensional (3D) haptic biomodels, or rapid prototyping (RP), has transformed the way surgeons conduct preoperative planning. In contrast to earlier RP techniques such as stereolithography, 3D printing has introduced fast, affordable office-based manufacturing. We introduce the concept of 4D printing for the first time by introducing time as the fourth dimension to 3D printing. METHODS: The bones of the thumb ray are 3D printed during various movements to demonstrate four-dimensional (4D) printing. Principles and validation studies are presented here. RESULTS: 4D computed tomography was performed using "single volume acquisition" technology to reduce the exposure to radiation. Three representative scans of each thumb movement (i.e., abduction, opposition, and key pinch) were selected and then models were fabricated using a 3D printer. For validation, the angle between the first and the second metacarpals from the 4D imaging data and the 4D-printed model was recorded and compared. CONCLUSION: We demonstrate how 4D printing accurately depicts the transition in the position of metacarpals during thumb movement. With a fourth dimension of time, 4D printing delivers complex spatiotemporal anatomical details effortlessly and may substantially improve preoperative planning.

The operating theatre as classroom: a qualitative study of learning and teaching surgical competencies.

BACKGROUND: There has been a worldwide movement toward competency-based medical education and training. However, this is the first qualitative study to analyze the perceptions of surgical trainees and surgeons toward competency-based education in the operating theatre. We aim to examine views toward the specific learning and teaching of the nine competencies of the Royal Australasian College of Surgeons (RACS) and to explore perceived ideal conditions and challenges for learning and teaching these competencies in the operating theatre. METHODS: Individual semi-structured interviews with surgical trainees and surgeons in the specialty of General Surgery. Ten surgical trainees and surgeons who worked together were purposively sampled, for maximum variation, from an outer metropolitan public hospital in Melbourne, Australia, to identify emergent themes relating to learning and teaching surgical competencies in the operating theatre. RESULTS: Five themes were identified as: (1) Learning and teaching specific surgical competencies is through relationship based mentoring and experiential learning; (2) Ideal conditions and challenges in the operating theatre are availability of time and personal attitude; (3) Level of pre-operative briefing was variable; (4) Intra-operative teaching is perceived as structured; and, (5) Post-operative debriefing is recognized as ideal but not consistently performed. DISCUSSION: Professional relationships are important to both surgical trainees and surgeons in the process of learning and teaching competencies. Ad hoc apprenticeship style learning is perceived to remain prominent in the operating theatre. Sufficient time for training is valued by both groups. The surgical competencies are inherently different to each other. Some appear more difficult to learn and teach in the operating theatre, with technical expertise most readily identified and health advocacy least so. Elements of guided discovery learning and other educational models are described. Further emphasis on structured competency-based teaching methods may be beneficial for surgical trainees, surgeons and other specialties, both in Australia and worldwide.

3D volumetric analysis for planning breast reconstructive surgery.

Breast reconstruction plays an integral role in the holistic management of breast cancer, with assessment of breast volume, shape, and projection vital in planning breast reconstruction surgery. Current practice includes two-dimensional (2D) photography and visual estimation in selecting ideal volume and shape of breast implants or soft-tissue flaps. Other objective quantitative means of calculating breast volume have been reported, such as direct anthropomorphic measurements or three-dimensional (3D) photography, but none have proven reliably accurate. We describe a novel approach to volumetric analysis of the breast, through the creation of a haptic, tactile model, or 3D print of scan data. This approach comprises use of a single computed tomography (CT) or magnetic resonance imaging (MRI) scan for volumetric analysis, which we use to compare to simpler estimation techniques, create software-generated 3D reconstructions, calculate, and visualize volume differences, and produce biomodels of the breasts using a 3D printer for tactile appreciation of volume differential. Using the technique described, parenchymal volume was assessed and calculated using CT data. A case report was utilized in a pictorial account of the technique, in which a volume difference of 116 cm(3) was calculated, aiding reconstructive planning. Preoperative planning, including volumetric analysis can be used as a tool to aid esthetic outcomes and attempt to reduce operative times in post-mastectomy breast reconstruction surgery. The combination of accurate volume calculations and the production of 3D-printed haptic models for tactile feedback and operative guidance are evolving techniques in volumetric analysis and preoperative planning in breast reconstruction.

Overexpression of cellular iron import proteins is associated with malignant progression of esophageal adenocarcinoma.

PURPOSE: There is growing evidence that iron is important in esophageal adenocarcinoma, a cancer whose incidence is rising faster than any other in the Western world. However, how iron mediates carcinogenesis at the molecular level remains unclear. In this study, we investigated the expression of iron transport proteins involved in cellular iron import, export, and storage in the premalignant lesion Barrett's metaplasia and esophageal adenocarcinoma. EXPERIMENTAL DESIGN: Perls' staining was used to examine iron deposition in tissue. mRNA expression in samples of Barrett's metaplasia matched with esophageal adenocarcinoma and samples of Barrett's metaplasia without evidence of adenocarcinoma were examined by real-time PCR. Semiquantitative immunohistochemistry was used to examine cellular localization and protein levels. The effect of iron loading on cellular proliferation and iron transporter expression was determined in esophageal cell lines OE33 and SEG-1 using a bromodeoxyuridine assay and real-time PCR, respectively. RESULTS: In the progression of Barrett's metaplasia to adenocarcinoma, there was overexpression of divalent metal transporter 1 (DMT1), transferrin receptor 1, duodenal cytochrome b, ferroportin, and H-ferritin, and these changes were associated with increased iron deposition. Overexpression of DMT1 was further associated with metastatic adenocarcinoma. Iron loading OE33 and SEG-1 cells caused increased cellular proliferation, which was associated with increased H-ferritin and decreased transferrin receptor 1 and DMT1 expression. CONCLUSIONS: Progression to adenocarcinoma is associated with increased expression of iron import proteins. These events culminate in increased intracellular iron and cellular proliferation. This may represent a novel mechanism of esophageal carcinogenesis.

Epithelial-mesenchymal transition mediated tumourigenesis in the gastrointestinal tract.

Epithelial-mesenchymal transition (EMT) is a highly conserved process that has been well characterised in embryogenesis. Studies have shown that the aberrant activation of EMT in adult epithelia can promote tumour metastasis by repressing cell adhesion molecules, including epithelial (E)-cadherin. Reduced intracellular adhesion may allow tumour cells to disseminate and spread throughout the body. A number of transcription proteins of the Snail superfamily have been implicated in EMT. These proteins have been shown to be over-expressed in advanced gastrointestinal (GI) tumours including oesophageal adenocarcinomas, colorectal carcinomas, gastric and pancreatic cancers, with a concomitant reduction in the expression of E-cadherin. Regulators of EMT may provide novel clinical targets to detect GI cancers early, so that cancers previously associated with a poor prognosis such as pancreatic cancer can be diagnosed before they become inoperable. Furthermore, pharmacological therapies designed to inhibit these proteins will aim to prevent local and distant tumour invasion.

Overexpression of Slug is associated with malignant progression of esophageal adenocarcinoma.

AIM: To characterise expression of known E-cadherin repressors; Snail, Slug and Twist in the development of esophageal adenocarcinoma. METHODS: E-cadherin, Slug, Snail and Twist mRNA expression in Barrett's metaplasia and esophageal adenocarcinoma specimens was examined by real-time reverse transcription-polymerase chain reaction (RT-PCR). Semi-quantitative immunohistochemistry was used to examine cellular localisation and protein levels. The effect of Slug on epithelial mesenchymal transition (EMT) markers was examined by transfection of Slug into an adenocarcinoma line OE33. RESULTS: Cellular localisation of Slug in Barrett's metaplasia was largely cytoplasmic whilst in adenocarcinoma it was nuclear. Semi-quantitative analysis indicated that Slug was more abundant in adenocarcinoma compared to matched Barrett's metaplastic specimens. Snail and Twist were expressed in adenocarcinoma but were cytoplasmic in location and not induced compared to Barrett's mucosa. These observations were supported by mRNA studies where only Slug mRNA was shown to be over-expressed in adenocarcinoma and inversely correlated to E-cadherin expression. Overexpression of Slug in OE33 mediated E-cadherin repression and induced the mesenchymal markers vimentin and fibronectin. CONCLUSION: Progression to adenocarcinoma is associated with increased Slug expression and this may represent a mechanism of E-cadherin silencing.

Increased hepcidin expression in colorectal carcinogenesis.

AIM: To investigate whether the iron stores regulator hepcidin is implicated in colon cancer-associated anaemia and whether it might have a role in colorectal carcinogenesis. METHODS: Mass spectrometry (MALDI-TOF MS and SELDI-TOF MS) was employed to measure hepcidin in urine collected from 56 patients with colorectal cancer. Quantitative Real Time RT-PCR was utilised to determine hepcidin mRNA expression in colorectal cancer tissue. Hepcidin cellular localisation was determined using immunohistochemistry. RESULTS: We demonstrate that whilst urinary hepcidin expression was not correlated with anaemia it was positively associated with increasing T-stage of colorectal cancer (P<0.05). Furthermore, we report that hepcidin mRNA is expressed in 34% of colorectal cancer tissue specimens and was correlated with ferroportin repression. This was supported by hepcidin immunoreactivity in colorectal cancer tissue. CONCLUSION: We demonstrate that systemic hepcidin expression is unlikely to be the cause of the systemic anaemia associated with colorectal cancer. However, we demonstrate for the first time that hepcidin is expressed by colorectal cancer tissue and that this may represent a novel oncogenic signalling mechanism.

Outcome of surgical fundoplication for extraesophageal (atypical) manifestations of gastroesophageal reflux disease in adults: a systematic review.

BACKGROUND: A significant proportion of patients with gastroesophageal reflux disease (GERD) present with atypical symptoms (extraesophageal reflux; EER). The effectiveness of surgical fundoplication in treating classical reflux symptoms is well documented, but the role of surgery in alleviating EER symptoms is less clear. The aim of this study was to review the published literature to determine whether surgical fundoplication is effective in controlling EER. MATERIALS AND METHODS: A Medline, PubMed, and Cochrane database search was done to find articles on surgery for extraesophageal reflux (1991-2006). Articles on pediatric patients were excluded. The parameters looked at were patient selection, resolution of symptoms, change in the quality of life, and any adverse outcomes. RESULTS: In 25 studies, a variable proportion (15-95%) of patients with various symptoms of EOR improved after surgical fundoplication. The percentage of patients with EER responding to surgery was less than that reported for classical GERD. CONCLUSIONS: The majority of patients in most studies seem to improve symptomatically after surgery. However, a small percentage remains unchanged or worsens. The reported studies are so disparate in their methodology that firm conclusions on the role of surgery are difficult. Further studies are needed. These should be large, multicenter, prospective trials comparing medical and surgical treatment with standardized diagnostic criteria for EER. Pre- and post-treatment assessment, the type of surgery performed, and follow-up should be standardized.

A systematic review of intraoperative process mapping in surgery.

Process mapping has been identified as a strategy to improve surgical efficiency but has been inconsistently applied in the literature and underutilised in surgical practice. In this journal, we recently described our utilisation of these approaches when applied to breast reconstruction. We showed that in surgery as complex as autologous breast reconstruction, process mapping can improve efficiency, and may improve surgical teaching, education and audit. The intraoperative period specifically is an area that can be applied not only to breast reconstruction, but to a much broader range of surgical procedures. A systematic review was undertaken of the databases Ovid MEDLINE, Allied and Complementary Medicine Database, Embase and PsychINFO. Manual searching of the references from articles identified was also conducted. Data items relating to the review aims were extracted from articles' methods, applications, and outcomes. A descriptive analysis was carried out to synthesise the information on the current usage of process mapping in the intraoperative period. Seventeen of 1,488 studies were eligible for review, with all of non-randomised study design. Studies had overlap in components of the intraoperative period to which process mapping was applied. Common areas of improvement were identified. Outcome measures were assessed in ten studies that implemented interventions based on the improvement areas to increase surgical efficiency. As such, process mapping has been used as part of larger quality improvement methods, albeit with inconsistent nomenclature, to improve surgical efficiency. While it has been applied to a range of surgical specialties, there is a lack of application to the surgical component of the intraoperative period. Greater consistency in the reporting and description of process mapping will enable further research for evidence of its benefits.

Breast volumetric analysis for aesthetic planning in breast reconstruction: a literature review of techniques.

BACKGROUND: Accurate volumetric analysis is an essential component of preoperative planning in both reconstructive and aesthetic breast procedures towards achieving symmetrization and patient-satisfactory outcome. Numerous comparative studies and reviews of individual techniques have been reported. However, a unifying review of all techniques comparing their accuracy, reliability, and practicality has been lacking. METHODS: A review of the published English literature dating from 1950 to 2015 using databases, such as PubMed, Medline, Web of Science, and EMBASE, was undertaken. RESULTS: Since Bouman's first description of water displacement method, a range of volumetric assessment techniques have been described: thermoplastic casting, direct anthropomorphic measurement, two-dimensional (2D) imaging, and computed tomography (CT)/magnetic resonance imaging (MRI) scans. However, most have been unreliable, difficult to execute and demonstrate limited practicability. Introduction of 3D surface imaging has revolutionized the field due to its ease of use, fast speed, accuracy, and reliability. However, its widespread use has been limited by its high cost and lack of high level of evidence. Recent developments have unveiled the first web-based 3D surface imaging program, 4D imaging, and 3D printing. CONCLUSIONS: Despite its importance, an accurate, reliable, and simple breast volumetric analysis tool has been elusive until the introduction of 3D surface imaging technology. However, its high cost has limited its wide usage. Novel adjunct technologies, such as web-based 3D surface imaging program, 4D imaging, and 3D printing, appear promising.

3D haptic modelling for preoperative planning of hepatic resection: A systematic review.

INTRODUCTION AND BACKGROUND: Three dimensional (3D) printing has gained popularity in the medical field because of increased research in the field of haptic 3D modeling. We review the role of 3D printing with specific reference to liver directed applications. METHODS: A literature search was performed using the scientific databases Medline and PubMed. We performed this in-line with the PRISMA [20] statement. We only included articles in English, available in full text, published about adults, about liver surgery and published between 2005 and 2015. The 3D model of a patient's liver venous vasculature and metastasis was prepared from a CT scan using Osirix software (Pixmeo, Gineva, Switzerland) and printed using our 3D printer (MakerBot Replicator Z18, US). To validate the model, measurements from the inferior vena cava (IVC) were compared between the CT scan and the 3D printed model. RESULTS: A total of six studies were retrieved on 3D printing directly related to a liver application. While stereolithography (STL) remains the gold standard in medical additive manufacturing, Fused Filament Fabrication (FFF), is cheaper and may be more applicable. We found our liver 3D model made by FFF had a 0.1 ± 0.06 mm margin of error (mean ± standard deviation) compared with the CT scans. CONCLUSION: 3D printing in general surgery is yet to be thoroughly exploited. The most relevant feature of interest with regard to liver surgery is the ability to view the 3D dimensional relationship of the various hepatic and portal veins with respect to tumor deposits when planning hepatic resection. Systematic review registration number: researchregistry1348.

Emerging Applications of Bedside 3D Printing in Plastic Surgery.

Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing intraoperative guidance tools, teaching patients and surgical trainees, and producing patient-specific prosthetics in everyday surgical practice.

Continuing rising trend in oesophageal adenocarcinoma.

Our study provides an update of the incidence of oesophageal cancer in the West Midland region of England and Wales from 1992-96. A total of 2,671 cases of oesophageal cancer were identified during the 5-year study period, with an age-standardised annual incidence (ASR) of 5.24 per 100,000 (95% CI: 5.02, 5.45). Similar numbers of adenocarcinoma and squamous cell carcinoma were found. Only 152 (5.6%) had no histology. There was a 5-fold difference in age-standardised annual incidence rates between males and females for adenocarcinoma of oesophagus, but no gender difference for squamous cell carcinoma. The parallel but higher ASR in males compared to females for adenocarcinoma of both oesophagus and cardia merits further investigation. The similarities in the patterns of age- and sex-specific rates and in the socioeconomic profiles could indicate a common aetiology for adenocarcinoma of oesophagus and gastric cardia. Quality control in Cancer Registries needs to focus on the accuracy and consistency of subsite classification to ensure that trends in incidence are identified. In the absence of accurate subsite classification of stomach cancers, the proportions of adenocarcinoma and squamous cell carcinoma of oesophagus (or the absolute rate of adenocarcinoma of oesophagus) may provide a useful tool in indicating whether adenocarcinoma of gastric cardia is likely to be increasing in incidence.