A comparison between 2- and 3-dimensional approaches to solid component measurement as radiological criteria for sublobar resection in lung adenocarcinoma ≤ 2 cm in size.

PURPOSE: We compared three-dimensional (3D) and two-dimensional (2D) measurements of the solid component to determine radiological criteria for sublobar resection of lung adenocarcinoma ≤ 2 cm in size. METHODS: We included 233 surgical cases. The maximum size of the solid component for 3D measurement was calculated by delineating the solid component on successive axial images and reconstructing the 3D surface model. RESULTS: The predictive performance for adenocarcinoma in situ (n = 43) and minimally invasive adenocarcinoma (n = 77) were equivalent to areas under the curve of 0.871 and 0.857 for 2D and 3D measurements (p = 0.229), respectively. A solid component of 5 mm had a prognostic impact on both measurements ( ≤ 5 mm versus > 5 mm; p = 0.003 for 2D and p = 0.002 for 3D, log-rank test). Survival rates at 5 years were 94.7-96.9% following lobectomy and sublobar resection among patients with a solid component ≤ 5 mm in size. Sublobar resection resulted in worse survival rates, with declines at 5 years of 15.8% on 2D and 11.5% on 3D measurements, than lobectomy in patients with a solid component > 5 mm in size. CONCLUSIONS: A solid component ≤ 5 mm in size is an appropriate criterion for sublobar resection for both measurements. In addition, 2D measurement is justified because of its simple implementation.

Development of Integrated 3-Dimensional Computer Graphics Human Head Model.

BACKGROUND: Understanding the complex anatomy of neurostructures is very important in various stages of medical education, from medical students to experienced neurosurgeons, and, ultimately, for the knowledge of human beings. OBJECTIVE: To develop an interactive computer graphics (CG) anatomic head model and present the current progress. METHODS: Based on the prior head 3-dimensional CG (3DCG) polygon model, 23 additional published papers and textbooks were consulted, and 2 neurosurgeons and 1 CG technician performed revision and additional polygon modeling. Three independent neurosurgeons scored the clear visibility of anatomic structures relevant to neurosurgical procedures (anterior petrosal and supracerebellar infratentorial approaches) in the integrated 3DCG model (i model) and patients' radiological images (PRIs) such as those obtained from computed tomography, magnetic resonance imaging, and angiography. RESULTS: The i model consisted of 1155 parts (.stl format), with a total of 313 763 375 polygons, including 10 times more information than the foundation model. The i model was able to illustrate complex and minute neuroanatomic structures that PRIs could not as well as extracranial structures such as paranasal sinuses. Our subjective analysis showed that the i model had better clear visibility scores than PRIs, particularly in minute nerves, vasculatures, and dural structures. CONCLUSION: The i model more clearly illustrates minute anatomic structures than PRIs and uniquely illustrates nuclei and fibers that radiological images do not. The i model complements cadaveric dissection by increasing accessibility according to spatial, financial, ethical, and social aspects and can contribute to future medical education.

Fluoroscopy-based laser guidance system for linear surgical tool insertion depth control.

PURPOSE: In most orthopedic surgeries, knowing how far to insert surgical tools is crucial. The objective of this study was to provide guidance information on depth without tracking surgical tools. A previously developed laser guidance system for linear surgical tool insertion uses two laser beams that display the insertion point and orientation on the skin surface. However, the system only provides 4 degrees of freedom guidance (an entry point on the planned pathway line and the orientation) but do not inform surgeons on the ideal insertion depth. METHOD: A 5-DOF guidance method was developed to provide guidance information by direct projection onto the surgical area using laser beams without tracking markers. A position and orientation guidance performed by two laser beams and depth guidance performed by a single laser beam are appeared on the surgical area in turn. However, depth point appears on the surgical tool side face with some error because of tool radius. Using the actual depth position, insertion path vector and location of the laser sources, the correct depth point on the tool's surface is calculated by the proposed method. So, this system can indicate and navigate the 5-DOF which is planning path and the correct depth point. RESULTS: An evaluation of the accuracy of depth guidance revealed a depth guidance error of 0.55±0.29 mm and results from phantom target insertions revealed overall system accuracies of 1.44 ± 1.09 mm, 0.91° ± 0.82°. In addition, overall system accuracies of application feasibility experiment under the X-ray condition were 1.94 ± 0.98mm, 1.39° ± 1.30°. CONCLUSION: A new surgical tool depth insertion method was developed using a fluorolaser guidance system. This tool informs surgeons of the surgical tool tip depth assuming that the insertion point and orientation are correct. The new method was tested successfully in vitro.

A fluorolaser navigation system to guide linear surgical tool insertion.

PURPOSE: Conventional navigation systems for minimally invasive orthopedic surgery require a secondary monitor to display guidance information generated with CT or MRI images. Newer systems use augmented reality to project surgical plans into binocular glasses. These surgical procedures are often mentally challenging and cumbersome to perform. METHOD: A comprehensive surgical navigation system for direct guidance while minimizing radiation exposure was designed and built. System accuracy was evaluated using in vitro needle insertion experiments. The fluoroscopic-based navigation technique is combined with an existing laser guidance technique. As a result, the combined system is capable of surgical planning using two or more X-ray images rather than CT or MRI scans. Guidance information is directly projected onto the patient using two laser beams and not via a secondary monitor. RESULTS: We performed 15 in vitro needle insertion experiments as well as 6 phantom pedicle screw insertion experiments to validate navigation system accuracy. The planning accuracy of the system was found to be 2.32 mm and 2.28°, while its overall guidance accuracy was found to be 2.40 mm and 2.39°. System feasibility was demonstrated by successfully performing percutaneous pin insertion on phantoms. CONCLUSION: Quantitative and qualitative evaluations of the fluorolaser navigation system show that it can support accurate guidance and intuitive surgical tool insertion procedures without preoperative 3D image volumes and registration processes.