Chris LeCastillo

All Publications

• Measuring Abdominal Skin-Surface Distances Using Photos for Perforator Mapping Analysis-A Validation Study on 3D-Printed DIEP-Flap Models. The international journal of medical robotics + computer assisted surgery : MRCAS Necker, F. N., Cholok, D. J., Fischer, M. J., Gifford, K., Le Castillo, C., Scholz, M., Januszyk, M., Leuze, C. W., Daniel, B. L., Momeni, A. 2025; 21 (5): e70108

  Abstract

  BACKGROUND: We present a novel method for accurately measuring skin-surface distances using standard smartphone photos and Photoshop, validated on 3D-printed DIEP-flap models and on calibration grid-patterns.MATERIALS AND METHODS: Distance measurements are acquired in Photoshop in a calibration plane between dots on a grid-pattern as well as between perforators on photos of 3D-printed models and compared against ground-truth. Margins of errors are calculated from fitted linear models.RESULTS: Submillimeter accuracy can be achieved within errors of ±0.45mm (80% probability) and ±0.8mm (95% probability) for measuring distances on the dot-grid. On the 3D-printed DIEP-models, distance measurements are accurate within ±1.75mm (80% probability) and ±3.1mm (95% probability).CONCLUSIONS: We introduce a simple yet highly accurate technique to measure skin-surface distances using normal photos. Depending on the scenario, submillimeter or conservatively very low millimetre errors can be achieved, sufficiently accurate for clinical use, whilst maintaining topographic relationships of the measurements.

  View details for DOI 10.1002/rcs.70108

  View details for PubMedID 40963200

• Nested Semi-Transparent Isosurface Simulated Volume-Rendering (NESTIS-VR) - An efficient on-device rendering approach for Augmented Reality headsets increasing surgeon confidence of kidney donor arterial anatomy. Computers in biology and medicine Necker, F. N., Melcher, M. L., Busque, S., Leuze, C. W., Ghanouni, P., Le Castillo, C., Nguyen, E., Daniel, B. L. 2024; 183: 109267

  Abstract

  Volume-renderings of computed tomography or magnetic resonance angiograms (MRAs) are routinely used by surgeons in the preoperative assessment of vascular anatomy in kidney donors. Stereoscopic headsets (OST-HMD) like Microsoft HoloLens allow intuitive interaction with three-dimensional content for more intuitive comprehension, but do not allow real-time ray-casting volume-rendering of medical volume datasets on-device due to computational limitations.We introduce NEsted Semi-Transparent Isosurface Simulated Volume-Rendering (NESTIS-VR), as an on-device alternative to ray-casting volume-rendering and developed an application for HoloLens to render kidney donor MRAs with interactive control of fundamental rendering parameters. We compared NESTIS-VR with current standard pre-calculated 2D ray-cast volume-renderings in an observational study with 2 expert kidney transplant surgeons, measuring their confidence in pre-operatively assessing the kidney pedicle arterial anatomy in 20 potential donors. We also compared it against other 3D rendering techniques to understand which features contributed most to any improvements.Real-time stereoscopic three-dimensional (3D) NESTIS-VR in Augmented Reality significantly improves surgeons' confidence compared with pre-calculated conventional two-dimensional (2D) ray-casting volume-rendered images (p = 0.0415/p = 0.00003). 2D non-stereoscopic NESTIS-VR was significantly superior to pre-calculated 2D ray-casting volume-rendered images for both surgeons (p = 0.044/p = 0.0003). Single isosurface 2D rendering was significantly superior than pre-calculated 2D volume-rendered images for one surgeon. There was no significant difference between binocular 3D display over 2D views with NESTIS-VR or between constrained and unconstrained vantage points for 2D viewing.NESTIS-VR provides a new approach to rendering medical datasets in computationally limited OST-HMD headsets and significantly increases surgeons' confidence of kidney donor arterial anatomy. The principal confidence benefit arises from providing surgeons interactive control over rendering parameters compared to pre-calculated renderings at preset parameters whilst rendering on-device and keeping the OST-HMD untethered from a workstation.

  View details for DOI 10.1016/j.compbiomed.2024.109267

  View details for PubMedID 39405728

• Suture Packaging as a Marker for Intraoperative Image Alignment in Augmented Reality on Mobile Devices. Plastic and reconstructive surgery. Global open Necker, F. N., Cholok, D. J., Shaheen, M. S., Fischer, M. J., Gifford, K., Le Castillo, C., Scholz, M., Leuze, C. W., Daniel, B. L., Momeni, A. 2024; 12 (6): e5933

  Abstract

  Preoperative vascular imaging has become standard practice in the planning of microsurgical breast reconstruction. Currently, translating perforator locations from radiological findings to a patient's abdomen is often not easy or intuitive. Techniques using three-dimensional printing or patient-specific guides have been introduced to superimpose anatomy onto the abdomen for reference. Augmented and mixed reality is currently actively investigated for perforator mapping by superimposing virtual models directly onto the patient. Most techniques have found only limited adoption due to complexity and price. Additionally, a critical step is aligning virtual models to patients. We propose repurposing suture packaging as an image tracking marker. Tracking markers allow quick and easy alignment of virtual models to the individual patient's anatomy. Current techniques are often complicated or expensive and limit intraoperative use of augmented reality models. Suture packs are sterile, readily available, and can be used to align abdominal models on the patients. Using an iPad, the augmented reality models automatically align in the correct position by using a suture pack as a tracking marker. Given the ubiquity of iPads, the combination of these devices with readily available suture packs will predictably lower the barrier to entry and utilization of this technology. Here, our workflow is presented along with its intraoperative utilization. Additionally, we investigated the accuracy of this technology.

  View details for DOI 10.1097/GOX.0000000000005933

  View details for PubMedID 38919516

  View details for PubMedCentralID PMC11199004

• The utility of three-dimensional models in complex microsurgical reconstruction. Archives of plastic surgery Ogunleye, A. A., Deptula, P. L., Inchauste, S. M., Zelones, J. T., Walters, S. n., Gifford, K. n., LeCastillo, C. n., Napel, S. n., Fleischmann, D. n., Nguyen, D. H. 2020; 47 (5): 428–34

  Abstract

  Three-dimensional (3D) model printing improves visualization of anatomical structures in space compared to two-dimensional (2D) data and creates an exact model of the surgical site that can be used for reference during surgery. There is limited evidence on the effects of using 3D models in microsurgical reconstruction on improving clinical outcomes.A retrospective review of patients undergoing reconstructive breast microsurgery procedures from 2017 to 2019 who received computed tomography angiography (CTA) scans only or with 3D models for preoperative surgical planning were performed. Preoperative decision-making to undergo a deep inferior epigastric perforator (DIEP) versus muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flap, as well as whether the decision changed during flap harvest and postoperative complications were tracked based on the preoperative imaging used. In addition, we describe three example cases showing direct application of 3D mold as an accurate model to guide intraoperative dissection in complex microsurgical reconstruction.Fifty-eight abdominal-based breast free-flaps performed using conventional CTA were compared with a matched cohort of 58 breast free-flaps performed with 3D model print. There was no flap loss in either group. There was a significant reduction in flap harvest time with use of 3D model (CTA vs. 3D, 117.7±14.2 minutes vs. 109.8±11.6 minutes; P=0.001). In addition, there was no change in preoperative decision on type of flap harvested in all cases in 3D print group (0%), compared with 24.1% change in conventional CTA group.Use of 3D print model improves accuracy of preoperative planning and reduces flap harvest time with similar postoperative complications in complex microsurgical reconstruction.

  View details for DOI 10.5999/aps.2020.00829

  View details for PubMedID 32971594