Virtual Reality for Preoperative Planning in Complex Surgical Oncology: A Single-Center Experience.

INTRODUCTION: Virtual reality models (VRM) are three-dimensional (3D) simulations of two-dimensional (2D) images, creating a more accurate mental representation of patient-specific anatomy. METHODS: Patients were retrospectively identified who underwent complex oncologic resections whose operations differed from preoperative plans between April 2018 and April 2019. Virtual reality modeling was performed based on preoperative 2D images to assess feasibility of use of this technology to create models. Preoperative plans made based upon 2D imaging versus VRM were compared to the final operations performed. Once the use of VRM to create preoperative plans was deemed feasible, individuals undergoing complex oncologic resections whose operative plans were difficult to define preoperatively were enrolled prospectively from July 2019 to December 2021. Preoperative plans made based upon 2D imaging and VRM by both the operating surgeon and a consulting surgeon were compared to the operation performed. Confidence in each operative plan was also measured. RESULTS: Twenty patients were identified, seven retrospective and 13 prospective, with tumors of the liver, pancreas, retroperitoneum, stomach, and soft tissue. Retrospectively, VRM were unable to be created in one patient due to a poor quality 2D image; the remainder (86%) were successfully able to be created and examined. Virtual reality modeling more clearly defined the extent of resection in 50% of successful cases. Prospectively, all VRM were successfully performed. The concordance of the operative plan with VRM was higher than with 2D imaging (92% versus 54% for the operating surgeon and 69% versus 23% for the consulting surgeon). Confidence in the operative plan after VRM compared to 2D imaging also increased for both surgeons (by 15% and 8% for the operating and consulting surgeons, respectively). CONCLUSIONS: Virtual reality modeling is feasible and may improve preoperative planning compared to 2D imaging. Further investigation is warranted.

Virtual reality applications in pediatric surgery.

Virtual reality modeling (VRM) is a 3-dimensional (3D) simulation. It is a powerful tool and has multiple uses and applications in pediatric surgery. Patient-specific 2-dimensional imaging can be used to generate a virtual reality model, which can improve anatomical perception and understanding, and can aid in preoperative planning for complex operations. VRM can also be used for realistic training and simulation. It has also proven effective in distraction for pediatric patients experiencing pain and/or anxiety. We detail the technical requirements and process required for VRM generation, the applications, and future directions.

Pioneering Patient-Specific Approaches for Precision Surgery Using Imaging and Virtual Reality.

Endovascular treatment of complex vascular anomalies shifts the risk of open surgical procedures to the benefit of minimally invasive endovascular procedural solutions. Complex open surgical procedures used to be the only option for the treatment of a myriad of conditions like pulmonary and aortic valve replacement as well as cerebral aneurysm repair. However, due to advancements in catheter-delivered devices and operator expertise, these procedures (along with many others) can now be performed through minimally invasive procedures delivered through a central or peripheral vein or artery. The decision to shift from an open procedure to an endovascular approach is based on multi-modal imaging, often including 3D Digital Imaging and Communications in Medicine (DICOM) imaging datasets. Utilizing these 3D images, our lab generates 3D models of the pathologic anatomy, thereby allowing the pre-procedural analysis necessary to pre-plan critical components of the catheterization lab procedure, namely, C-arm positioning, 3D measurement, and idealized road-map generation. This article describes how to take segmented 3D models of patient-specific pathology and predict generalized C-arm positions, how to measure critical two-dimensional (2D) measurements of 3D structures relevant to the 2D fluoroscopy projections, and how to generate 2D fluoroscopy roadmap analogs that can assist in proper C-arm positioning during catheterization lab procedures.

Creation of Patient-Specific Silicone Cardiac Models with Applications in Pre-surgical Plans and Hands-on Training.

Three dimensional models can be a valuable tool for surgeons as they develop surgical plans and medical fellows as they learn about complex cases. In particular, 3D models can play an important role in the field of cardiology, where complex congenital heart diseases occur. While many 3D printers can provide anatomically correct and detailed models, existing 3D printing materials fail to replicate myocardial tissue properties and can be extremely costly. This protocol aims to develop a process for the creation of patient-specific models of complex congenital heart defects using a low-cost silicone that more closely matches cardiac muscle properties. With improved model fidelity, actual surgical procedural training could occur in advance of the procedure. Successful creation of cardiac models begins with the segmentation of radiologic images to generate a virtual blood pool (blood that fills the chambers of the heart) and myocardial tissue mold. The blood pool and myocardial mold are 3D printed in acrylonitrile butadiene styrene (ABS), a plastic dissolvable in acetone. The mold is assembled around the blood pool, creating a negative space simulating the myocardium. Silicone with a shore hardness of 2A is poured into the negative space and allowed to cure. The myocardial mold is removed, and the remaining silicone/blood pool model is submerged in acetone. The described process results in a physical model in which all cardiac features, including intra-cardiac defects, are represented with more realistic tissue properties and are more closely approximated than a direct 3D printing approach. The successful surgical correction of a model with a ventricular septal defect (VSD) using a GORE-TEX patch (standard surgical intervention for defect) demonstrates the utility of the method.

Single pediatric center experience with multiple device implantation for complex secundum atrial septal defects.

OBJECTIVES: We analyzed the efficacy and complications of placing multiple transcatheter devices to correct complex ASD in a primarily pediatric population. BACKGROUND: Limited pediatric information exists regarding the safety and efficacy of using multiple devices for secundum atrial septal defects (ASD) when multiple defects are present. METHODS: Cath lab, echo, and clinical data were reviewed for 238 patients who underwent device closure of secundum ASD from 2000 to 2007 at a single pediatric center. Of those requiring multiple devices (n = 15), residual shunting and complications were assessed. RESULTS: 238 patients (mean age 12 yrs; 80% < 16 yrs) underwent transcatheter ASD closure. 34 (14%) had multiple ASD, but only 15 received multiple devices (2 devices in 14 and 3 devices in 1). The mean age and weight (12 yrs; 35 kg) represent a younger population than previously reported. Only 3 were > 15 yrs, with a median age of 10.8 yrs (range 2-31). There was no compromise or obstruction to surrounding structures, and no device embolization or erosion was noted. A tiny thrombus was observed on the right sided screw of one device with no clinical sequelae. One patient (age 31 yrs) died at home 30 days post procedure from cardiac tamponade. Autopsy revealed the 3 intact devices in stable position without evidence of erosion. Latest available echo follow-up for the group revealed functional resolution of atrial level shunting in all patients. CONCLUSION: Multiple devices can safely and effectively be implanted in the pediatric population to close complex ASD.

Exploration of time sequential, patient specific 3D heart unlocks clinical understanding.

OBJECTIVES: The purpose was to create a time sequential three-dimensional virtual reality model, also referred to as a four-dimensional model, to explore its possible benefit and clinical applications. We hypothesized that this novel solution allows for the visuospatial benefits of the 3D model and the dynamic benefits of other existing imaging modalities. BACKGROUND: We have seen how 3D models hold great value in medical decision making by eliminating the variable visuospatial skills of practitioners. They have proved especially invaluable concerning the correction of congenital heart defects and have altered the course of many surgeries. There are, however, limitations to three-dimensional models. The static models only show what the heart looks like in one snapshot of its cycle and do not allow for an understanding of the physiological and dynamic processes. METHODS: This solution segments a 3D heart derived from a 2D image stack, times the 18 phases of a cardiac cycle and creates a 4D model that can be manipulated in space and time through the use of virtual reality. RESULTS: We believe the 4D heart provides a unique understanding of in situ cardiac anatomy not possible with other imaging techniques. Our expanding case series of clinician experiences and their immediate recognition of the potency of this technique is highly encouraging and reveals the future of functional and dynamic 4D representations of anatomy. CONCLUSIONS: The 4D heart improved our understanding around complex 3D relationships over time. We propose time and effort dedicated to 4D cardiac imaging analysis of dynamic cardiac pathologies such as hypertrophic obstructive cardiomyopathy or a pre-op Rastelli repair with a narrow outflow tract could offer tremendous insight into the medical decision-making process.

Comparison between transthoracic echocardiography and cardiac magnetic resonance imaging in patients status post atrial switch procedure.

OBJECTIVES: This study compares image quality, cost, right ventricular ejection fraction analysis, and baffle visualization between transthoracic echocardiography and cardiac magnetic resonance imaging in those status post atrial switch for transposition of the great arteries. BACKGROUND: This population requires imaging for serial evaluations. Transthoracic echocardiography is often first line but has drawbacks, many of which are addressed by cardiac magnetic resonance imaging. METHODS: Twelve patients (mean age 25 years) with relatively concurrent (mean 157 days) studies were included. Three separate echocardiography and magnetic resonance imaging physicians independently analyzed baffles, image quality, and right ventricular ejection fractions. Institutional and Medicaid charges were compared. RESULTS: For right ventricular ejection fraction, echocardiography (36.1%) underestimated cardiac magnetic resonance imaging (47.8%, P = .002). Image quality for transthoracic echocardiography was significantly rated lower than cardiac magnetic resonance imaging (P = .002). Baffles were better seen in cardiac magnetic resonance imaging (transthoracic echocardiography vs. cardiac magnetic resonance imaging: superior vena cava 86% vs. 100% [P = .063]; inferior vena cava 33% vs. 97% [P = .002]; pulmonary vein 92% vs. 100% [P = .250]). Comparing hospital charges and Medicaid reimbursement, transthoracic echocardiography respectively costs 18% and 38% less than cardiac magnetic resonance imaging. CONCLUSIONS: In conclusion, transthoracic echocardiography underestimated right ventricular ejection fraction compared to cardiac magnetic resonance imaging. Cardiac magnetic resonance imaging had consistently higher image quality and better visualization of the baffles. Cost differences are minimal. We propose that cardiac magnetic resonance imaging be considered first line for imaging in certain patients' status post atrial switch procedure.