Needs analysis and construction of a simulation mannequin for diagnosing head and neck cancer
Abstract
Besides imaging, the central step in diagnostics of head and neck cancer is biopsy and rigid triple endoscopy, a routine procedure for over 50 years. However, the assessment of this procedure in terms of comparative studies has so far been unfeasible for ethical and practical reasons. The goal set was to construct a simulation mannequin of lifelike synthetic tissue for the evaluation and training of triple endoscopy. Paired up as a tandem, mechanical engineering and medicine postgraduates captured the work environment and gross steps of the procedure by means of observations in the surgery room, creation of a workflow and brainstorming in a multidisciplinary team. The further specifications, derived from indepth interviews with eight ENT senior physicians, were as well incorporated into a quality function deployment (QFD), that resulted in focus on realistic, computed tomography (CT) scan based anatomy, lifelike haptics and optics of mucous membrane surfaces. These priorities lead to the decision to construct a modular triple endoscopy simulator which was integrated into a suitable mannequin already available on the market. As triple endoscopy was consistently judged by 100% of the interviewed ENT senior physicians as a challenging procedure the project was considered to be meaningful. The first consideration was to assess the procedure, which is now possible, but during the project time we decided to alter the weighting in the direction of simulator based training.
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Introduction
Approximately 50 out of 100.000 people in Germany develop head and neck cancer per annum (1). Among the diverse entities, ENT (Ear-Nose-Throath) oncologists most frequently deal with larynx- and hypopharynx carcinoma. According to EUROCARE-4 and -5 analysis the overall cure rate totals 42%, noted that carcinomas of the hypopharynx have a very poor prognosis with a cure rate of only 26% (2), (3). Besides imaging, the central step in diagnostics is rigid triple endoscopy and biopsy. In the course of the examination, a secondary malignancy can be detected in the upper airways and esophagus in approximately 2 to 7% of the cases (4), (5), and of same importance, the endoscopy allows accurate inspection and palpation. The tumor data that is collected during endoscopic examination is needed for a precise therapeutic decision in the tumorboard. Although this approach is valid for more than 50 years, it has never been assessed so far (6). Firstly, for ethical reasons it is problematic to repeat the same triple endoscopy under general anesthesia in one and the same patient during comparative studies. Secondly, the tumor undergoes instant alterations in the very moment of the examination. Therefore simulation mannequins of lifelike tissue are needed for such assessment studies.
Furthermore and despite of being a standard procedure, triple endoscopy can yet be considered as challenging and risky examination even for experienced surgeons. “Learning by doing” is no longer feasible against the background of patient safety and no longer viable given the fast-paced daily routine in the wards (7), (8), (9)..
Conclusion
Summing up, our methodical approach resulted in a streamlined development for a simulation mannequin for diagnosis of head and neck cancer. This simulator will support further assessment of triple endoscopy. Simulator based training is prerequisite for the improvement of patient safety.
For the construction of a simulator mannequin, work in “tandems” – consisting of a medical and construction engineer postgraduate - has turned out to be very valuable in the conception process. On-site visits and strong involvement of a clinical cooperation partner were indispensable for getting a detailed view on the task in its actual context. In-depth interviews and QFD were helpful tools to capture, analyze and at the same time to prioritize complex needs.
The further integration of sensors into our mannequin will improve the feedback for surgical training. Besides surgical training, the application of the simulator in difficult airway management and other applications is intented.