Development and validation of a cadaveric porcine Pseudotumor model for Oral Cancer biopsy and resection training.

OBJECTIVE: The gold standard of oral cancer (OC) treatment is diagnostic confirmation by biopsy followed by surgical treatment. However, studies have shown that dentists have difficulty performing biopsies, dental students lack knowledge about OC, and surgeons do not always maintain a safe margin during tumor resection. To address this, biopsies and resections could be trained under realistic conditions outside the patient. The aim of this study was to develop and to validate a porcine pseudotumor model of the tongue. METHODS: An interdisciplinary team reflecting various specialties involved in the oncological treatment of head and neck oncology developed a porcine pseudotumor model of the tongue in which biopsies and resections can be practiced. The refined model was validated in a final trial of 10 participants who each resected four pseudotumors on a tongue, resulting in a total of 40 resected pseudotumors. The participants (7 residents and 3 specialists) had an experience in OC treatment ranging from 0.5 to 27 years. Resection margins (minimum and maximum) were assessed macroscopically and compared beside self-assessed margins and resection time between residents and specialists. Furthermore, the model was evaluated using Likert-type questions on haptic and radiological fidelity, its usefulness as a training model, as well as its imageability using CT and ultrasound. RESULTS: The model haptically resembles OC (3.0 ± 0.5; 4-point Likert scale), can be visualized with medical imaging and macroscopically evaluated immediately after resection providing feedback. Although, participants (3.2 ± 0.4) tended to agree that they had resected the pseudotumor with an ideal safety margin (10 mm), the mean minimum resection margin was insufficient at 4.2 ± 1.2 mm (mean ± SD), comparable to reported margins in literature. Simultaneously, a maximum resection margin of 18.4 ± 6.1 mm was measured, indicating partial over-resection. Although specialists were faster at resection (p < 0.001), this had no effect on margins (p = 0.114). Overall, the model was well received by the participants, and they could see it being implemented in training (3.7 ± 0.5). CONCLUSION: The model, which is cost-effective, cryopreservable, and provides a risk-free training environment, is ideal for training in OC biopsy and resection and could be incorporated into dental, medical, or oncologic surgery curricula. Future studies should evaluate the long-term training effects using this model and its potential impact on improving patient outcomes.

Induction of Contralateral Hepatic Hypertrophy by Unilobar Yttrium-90 Transarterial Radioembolization versus Portal Vein Embolization: An Animal Study.

PURPOSE: To compare hepatic hypertrophy in the contralateral lobe achieved by unilobar transarterial radioembolization (TARE) versus portal vein embolization (PVE) in a swine model. METHODS: After an escalation study to determine the optimum dose to achieve hypertrophy after unilobar TARE in 4 animals, 16 pigs were treated by TARE (yttrium-90 resin microspheres) or PVE (lipiodol/n-butyl cyanoacrylate). Liver volume was calculated based on CT before treatment and during 6 months of follow-up. Independent t-test (P < .05) was used to compare hypertrophy. The relationship between hypertrophy after TARE and absorbed dose was calculated using the Pearson correlation. RESULTS: At 2 and 4 weeks after treatment, a significantly higher degree of future liver remnant hypertrophy was observed in the PVE group versus the TARE group, with a median volume gain of 31% (interquartile range [IQR]: 16%-66%) for PVE versus 23% (IQR: 6%-36%) for TARE after 2 weeks and 51% (IQR: 47%-69%) for PVE versus 29% (IQR: 20%-50%) for TARE after 4 weeks. After 3 and 6 months, hypertrophy converged without a statistically significant difference, with a volume gain of 103% (IQR: 86%-119%) for PVE versus 82% (IQR: 70%-96%) for TARE after 3 months and 115% (IQR: 70%-46%) for PVE versus 86% (IQR: 58%-111%) for TARE after 6 months. A strong correlation was observed between radiation dose (median 162 Gy, IQR: 139-175) and hypertrophy. CONCLUSIONS: PVE resulted in rapid hypertrophy within 1 month of the procedure, followed by a plateau, whereas TARE resulted in comparable hypertrophy by 3-6 months. TARE-induced hypertrophy correlated with radiation absorbed dose.

A personalized approach to interventional treatment of tricuspid regurgitation: experiences from an acute animal study.

OBJECTIVES: Interventional treatment of tricuspid valve disease has so far received little attention due to the anatomical challenges in a thrombogenic surrounding. In the present study, we present an imaging-based, personalized interventional approach to the therapy of tricuspid regurgitation. METHODS: In our porcine model, we used rapid prototyping to build a matrix reproducing the geometry of the right atrium that was previously derived from computer tomography (CT) scans. Over this matrix, a braided nitinol device fitting almost completely the right atrium was crafted. An additional tubular stent component was developed to carry a tissue valve prosthesis. This part was designed to be connectable to the annular portion of the main device. In our feasibility study, the crimped device was implanted via jugular access into the right atrium of 12 pigs and expanded subsequently. Following isolated implantation of the device without the valve-carrying component, further procedures included implantation of the whole composite device, including the mentioned tissue valve. Representing a only feasibility study, all implantations were performed under full bypass and direct sight. On-site visualization was performed by both echocardiography and fluoroscopy. Additional imaging was realized by postoperative CT scans. RESULTS: Following implantation, 9 of 12 animals were weaned from cardiopulmonary bypass. Correct positioning of the device and orthodromic blood flow as maintained by the valve prosthesis were demonstrated by echocardiography and fluoroscopy. Postoperative contrast CT evaluation demonstrated proper fitting of the device into the right-sided heart cavities without obstruction of the outflow tract. Autopsy additionally confirmed its correct positioning without major trauma to surrounding structures. CONCLUSIONS: We demonstrated the feasibility in principle of a personalized interventional treatment for tricuspid regurgitation using a braided stent, based on individual cardiac imaging, with anchoring forces mainly exerted on the venae cavae and on the inner surface of the right atrium. The design process of this device is a good indicator of the growing potential of an imaging-based personalized simulation and production approach for the treatment of tricuspid valve disease.