3-DIEPrinting: 3D-printed Models to Assist the Intramuscular Dissection in Abdominally Based Microsurgical Breast Reconstruction

The Reconstructive Metaverse - Collaboration in Real-Time Shared Mixed Reality Environments for Microsurgical Reconstruction

Plastic surgeons routinely use 3D-models in their clinical practice, from 3D-photography and surface imaging to 3D-segmentations from radiological scans. However, these models continue to be viewed on flattened 2D screens that do not enable an intuitive understanding of 3D-relationships and cause challenges regarding collaboration with colleagues. The Metaverse has been proposed as a new age of applications building on modern Mixed Reality headset technology that allows remote collaboration on virtual 3D-models in a shared physical-virtual space in real-time. We demonstrate the first use of the Metaverse in the context of reconstructive surgery, focusing on preoperative planning discussions and trainee education. Using a HoloLens headset with the Microsoft Mesh application, we performed planning sessions for 4 DIEP-flaps in our reconstructive metaverse on virtual patient-models segmented from routine CT angiography. In these sessions, surgeons discuss perforator anatomy and perforator selection strategies whilst comprehensively assessing the respective models. We demonstrate the workflow for a one-on-one interaction between an attending surgeon and a trainee in a video featuring both viewpoints as seen through the headset. We believe the Metaverse will provide novel opportunities to use the 3D-models that are already created in everyday plastic surgery practice in a more collaborative, immersive, accessible, and educational manner.

HoloDIEP-Faster and More Accurate Intraoperative DIEA Perforator Mapping Using a Novel Mixed Reality Tool

BACKGROUND

 Microsurgical breast reconstruction using abdominal tissue is a complex procedure, in part, due to variable vascular/perforator anatomy. Preoperative computed tomography angiography (CTA) has mitigated this challenge to some degree; yet it continues to pose certain challenges. The ability to map perforators with Mixed Reality has been demonstrated in case studies, but its accuracy has not been studied intraoperatively. Here, we compare the accuracy of "HoloDIEP" in identifying perforator location (vs. Doppler ultrasound) by using holographic 3D models derived from preoperative CTA.

METHODS

 Using a custom application on HoloLens, the deep inferior epigastric artery vascular tree was traced in 15 patients who underwent microsurgical breast reconstruction. Perforator markings were compared against the 3D model in a coordinate system centered on the umbilicus. Holographic- and Doppler-identified markings were compared using a perspective-corrected photo technique against the 3D model along with measurement of duration of perforator mapping for each technique.

RESULTS

 Vascular points in HoloDIEP skin markings were -0.97 ± 6.2 mm (perforators: -0.62 ± 6.13 mm) away from 3D-model ground-truth in radial length from the umbilicus at a true distance of 10.81 ± 6.14 mm (perforators: 11.40 ± 6.15 mm). Absolute difference in radial distance was twice as high for Doppler markings compared with Holo-markings (9.71 ± 6.16 and 4.02 ± 3.20 mm, respectively). Only in half of all cases (7/14), more than 50% of the Doppler-identified points were reasonably close (<30 mm) to 3D-model ground-truth. HoloDIEP was twice as fast as Doppler ultrasound (76.9s vs. 150.4 s per abdomen).

CONCLUSION

 HoloDIEP allows for faster and more accurate intraoperative perforator mapping than Doppler ultrasound.

Leveraging the Apple Ecosystem: Easy Viewing and Sharing of Three-dimensional Perforator Visualizations via iPad/iPhone-based Augmented Reality

We introduce a novel technique using augmented reality (AR) on smartphones and tablets, making it possible for surgeons to review perforator anatomy in three dimensions on the go. Autologous breast reconstruction with abdominal flaps remains challenging due to the highly variable anatomy of the deep inferior epigastric artery. Computed tomography angiography has mitigated some but not all challenges. Previously, volume rendering and different headsets were used to enable better three-dimensional (3D) review for surgeons. However, surgeons have been dependent on others to provide 3D imaging data. Leveraging the ubiquity of Apple devices, our approach permits surgeons to review 3D models of deep inferior epigastric artery anatomy segmented from abdominal computed tomography angiography directly on their iPhone/iPad. Segmentation can be performed in common radiology software. The models are converted to the universal scene description zipped format, which allows immediate use on Apple devices without third-party software. They can be easily shared using secure, Health Insurance Portability and Accountability Act-compliant sharing services already provided by most hospitals. Surgeons can simply open the file on their mobile device to explore the images in 3D using "object mode" natively without additional applications or can switch to AR mode to pin the model in their real-world surroundings for intuitive exploration. We believe patient-specific 3D anatomy models are a powerful tool for intuitive understanding and communication of complex perforator anatomy and would be a valuable addition in routine clinical practice and education. Using this one-click solution on existing devices that is simple to implement, we hope to streamline the adoption of AR models by plastic surgeons.

Three-Dimensional Printing in Breast Reconstruction: Current and Promising Applications

Three-dimensional (3D) printing is dramatically improving breast reconstruction by offering customized and precise interventions at various stages of the surgical process. In preoperative planning, 3D imaging techniques, such as computer-aided design, allow the creation of detailed breast models for surgical simulation, optimizing surgical outcomes and reducing complications. During surgery, 3D printing makes it possible to customize implants and precisely shape autologous tissue flaps with customized molds and scaffolds. This not only improves the aesthetic appearance, but also conforms to the patient's natural anatomy. In addition, 3D printed scaffolds facilitate tissue engineering, potentially favoring the development and integration of autologous adipose tissue, thus avoiding implant-related complications. Postoperatively, 3D imaging allows an accurate assessment of breast volume and symmetry, which is crucial in assessing the success of reconstruction. The technology is also a key educational tool, enhancing surgeon training through realistic anatomical models and surgical simulations. As the field evolves, the integration of 3D printing with emerging technologies such as biodegradable materials and advanced imaging promises to further refine breast reconstruction techniques and outcomes. This study aims to explore the various applications of 3D printing in breast reconstruction, addressing current challenges and future opportunities.

Suture Packaging as a Marker for Intraoperative Image Alignment in Augmented Reality on Mobile Devices

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.

Analysis of Operation Duration in Thoracodorsal Artery Perforator Free-Flap Surgery of the Lower Extremities

PURPOSE

This retrospective study aimed to identify the factors that affect the duration of thoracodorsal artery perforator (TDAP) free-flap surgery and to offer strategies for optimizing the surgical procedure.

METHODS

We analyzed 80 TDAP flap surgeries performed by a single surgeon between January 2020 and December 2022, specifically focusing on free flaps used for lower-extremity defects with single-artery and single-vein anastomosis. The operation duration was defined as the time between the surgeon's initial incision and completion of reconstruction. Linear regression analyses were conducted to identify the factors affecting operation duration.

RESULTS

The average operative duration was 149 minutes (range, 80-245 minutes). All flaps survived, although 8 patients experienced partial flap loss. The operative duration decreased with increasing patient age and when end-to-end arterial anastomosis was performed. However, the risk increased with larger flap sizes and in patients with end-stage renal disease.

CONCLUSIONS

Our study identified several factors and methods that could accelerate TDAP free-flap procedures. These findings offer valuable insights for optimizing surgical processes and improving overall surgical outcomes. Although further research is needed to confirm and expand upon these findings, our study provides important guidance for surgeons in developing effective strategies for TDAP flap surgery.

Spatial Fidelity of Microvascular Perforating Vessels as Perceived by Augmented Reality Virtual Projections

BACKGROUND

Autologous breast reconstruction yields improved long-term aesthetic results but requires increased resources of practitioners and hospital systems. Innovations in radiographic imaging have been increasingly used to improve the efficiency and success of free flap harvest. Augmented reality affords the opportunity to superimpose relevant imaging on a surgeon's native field of view, potentially facilitating dissection of anatomically variable structures. To validate the spatial fidelity of augmented reality projections of deep inferior epigastric perforator flap-relevant anatomy, comparisons of three-dimensional (3D) models and their virtual renderings were performed by four independent observers. Measured discrepancies between the real and holographic models were evaluated.

METHODS

The 3D-printed models of deep inferior epigastric perforator flap-relevant anatomy were fabricated from computed tomographic angiography data from 19 de-identified patients. The corresponding computed tomographic angiography data were similarly formatted for the Microsoft HoloLens to generate corresponding projections. Anatomic points were initially measured on 3D models, after which the corresponding points were measured on the HoloLens projections from two separate vantage points (V1 and V2). Statistical analyses, including generalized linear modeling, were performed to characterize spatial fidelity regarding translation, rotation, and scale of holographic projections.

RESULTS

Among all participants, the median translational displacement at corresponding points was 9.0 mm between the real-3D model and V1, 12.1 mm between the 3D model and V2, and 13.5 mm between V1 and V2.

CONCLUSION

Corresponding points, including topography of perforating vessels, for the purposes of breast reconstruction can be identified within millimeters, but there remain multiple independent contributors of error, most notably the participant and location at which the projection is perceived.

A History of Innovation: Tracing the Evolution of Imaging Modalities for the Preoperative Planning of Microsurgical Breast Reconstruction

Breast reconstruction is an essential component in the multidisciplinary management of breast cancer patients. Over the years, preoperative planning has played a pivotal role in assisting surgeons in planning operative decisions prior to the day of surgery. The evolution of preoperative planning can be traced back to the introduction of modalities such as ultrasound and colour duplex ultrasonography, enabling surgeons to evaluate the donor site's vasculature and thereby plan operations more accurately. However, the limitations of these techniques paved the way for the implementation of modern three-dimensional imaging technologies. With the advancements in 3D imaging, including computed tomography and magnetic resonance imaging, surgeons gained the ability to obtain detailed anatomical information. Moreover, numerous adjuncts have been developed to aid in the planning process. The integration of 3D-printing technologies has made significant contributions, enabling surgeons to create complex haptic models of the underlying anatomy. Direct infrared thermography provides a non-invasive, visual assessment of abdominal wall vascular physiology. Additionally, augmented reality technologies are poised to reshape surgical planning by providing an immersive and interactive environment for surgeons to visualize and manipulate 3D reconstructions. Still, the future of preoperative planning in breast reconstruction holds immense promise. Most recently, artificial intelligence algorithms, utilising machine learning and deep learning techniques, have the potential to automate and enhance preoperative planning processes. This review provides a comprehensive assessment of the history of innovation in preoperative planning for breast reconstruction, while also outlining key future directions, and the impact of artificial intelligence in this field.

Nanomedicine and nanoparticle-based delivery systems in plastic and reconstructive surgery

BACKGROUND

Nanotechnology and nanomedicine are rising novel fields in plastic and reconstructive surgery (PRS). The use of nanomaterials often goes with regenerative medicine. Due to their nanoscale, these materials stimulate repair at the cellular and molecular levels. Nanomaterials may be placed as components of nanocomposite polymers allowing enhancement of overall biochemical and biomechanical properties with improved scaffold properties, cellular attachment, and tissue regeneration. They may also be formulated as nanoparticle-based delivery systems for controlled release of signal factors or antimicrobials, for example. However, more studies on nanoparticle-based delivery systems still need to be done in this field. Nanomaterials are also used as frameworks for nerves, tendons, and other soft tissues.

MAIN BODY

In this mini-review, we focus on nanoparticle-based delivery systems and nanoparticles targeting cells for response and regeneration in PRS. Specifically, we investigate their roles in various tissue regeneration, skin and wound healing, and infection control. Cell surface-targeted, controlled-release, and inorganic nanoparticle formulations with inherent biological properties have enabled enhanced wound healing, tumor visualization/imaging, tissue viability, and decreased infection, and graft/transplantation rejection through immunosuppression.

CONCLUSIONS

Nanomedicine is also now being applied with electronics, theranostics, and advanced bioengineering technologies. Overall, it is a promising field that can improve patient clinical outcomes in PRS.

[Autologous Breast Reconstruction in Conjuction with Lymphatic Microsurgery in Breast Cancer-Related Lymphedema]

Breast cancer-related lymphedema of the upper extremity is the most significant non-oncological complication of tumour therapy, leading to functional impairment and impacting patients' quality of life. Autologous breast reconstruction per se effectively reduces incidence and stage of lymphedema after breast cancer treatment by surgical angiogenesis. In addition, modern surgical techniques for treating lymphedema are effective in reducing limb volume, circumference and functional impairment, and improving patients' quality of life, body image, integrity and local immunocompetence. Reconstructive surgery, including lymphovenous anastomoses (LVA) and vascularised lymph node transfer (VLNT), have been shown to rearrange or restore lymphatic flow and prevent stage progression. For patients with breast cancer-related lymphedema after mastectomy, autologous breast reconstruction in conjunction with lymphatic microsurgery using VLNT, LVA or a combination of these procedures offers the option of holistic and single-stage restoration in modern senology. Extensive scar release in the axilla is a crucial component of the surgical technique, aiming to prepare the recipient bed for the VLN transplant and to allow for the functional recruitment of remaining lymph vessels of the upper extremity. This article presents the indications, preoperative diagnostic evaluation, surgical techniques and precautions, complications and results of combined lymphatic and breast restoration.

Potential of Intraoperative 3D Photography and 3D Visualization in Breast Reconstruction

Although pre- and postoperative three-dimensional (3D) photography are well-established in breast reconstruction, intraoperative 3D photography is not. We demonstrate the process of intraoperative acquisition and visualization of 3D photographs for breast reconstruction and present clinicians' opinions about intraoperative visualization tools.

METHODS

Mastectomy specimens were scanned with a handheld 3D scanner during breast surgery. The 3D photographs were processed to compute morphological measurements of the specimen. Three visualization modalities (screen-based viewing, augmented reality viewing, and 3D printed models) were created to show different representations of the 3D photographs to plastic surgeons. We interviewed seven surgeons about the usefulness of the visualization methods.

RESULTS

The average time for intraoperative acquisition of 3D photographs of the mastectomy specimen was 4 minutes, 8 seconds ± 44 seconds. The average time for image processing to compute morphological measurements of the specimen was 54.26 ± 40.39 seconds. All of the interviewed surgeons would be more inclined to use intraoperative visualization if it displayed information that they are currently missing (eg, the target shape of the reconstructed breast mound). Additionally, the surgeons preferred high-fidelity visualization tools (such as 3D printing) that are easy-to-use and have minimal disruption to their current workflow.

CONCLUSIONS

This study demonstrates that 3D photographs can be collected intraoperatively within acceptable time limits, and quantitative measurements can be computed timely to be utilized within the same procedure. We also report surgeons' comments on usability of visualization methods and of measurements of the mastectomy specimen, which can be used to guide future surgical practice.

3D Printed Chest Wall: A Tool for Advanced Microsurgical Training Simulating Depth and Limited View

The deep inferior epigastric perforator (DIEP) flap has become the free flap of choice for autologous breast reconstruction. However, anastomoses of DIEP pedicles to internal mammary vessels in the chest wall are difficult due to restricted access and the depth of the vessels. Successful performance of such demanding procedures necessitates advanced requirements for microsurgical training models. The current chicken thigh model has been used to acquire microsurgical skills, allowing early learning curve trainees to practice repeatedly in inconsequential environments. Despite the increasing use of this model for training purposes, the resemblance to a clinical environment is tenuous. Such models should include anastomosis practice within the depth where the recipient vessels are located. To address this, we developed a three-dimensional (3D) printed chest wall as an addition to the current chicken thigh model, which reliably mimics the complexity of the anastomosis performed during DIEP breast reconstruction. This form of rapid prototyping facilitates a newfound ability for early learning curve trainees to exercise end-to-end anastomoses on vessels located with variable depths. Our enhancement of the current chicken thigh model is simple, cost-effective and offers a significantly more realistic resemblance to a clinical situation.

Applications of 3D printing in breast cancer management

Three-dimensional (3D) printing is a method by which two-dimensional (2D) virtual data is converted to 3D objects by depositing various raw materials into successive layers. Even though the technology was invented almost 40 years ago, a rapid expansion in medical applications of 3D printing has only been observed in the last few years. 3D printing has been applied in almost every subspecialty of medicine for pre-surgical planning, production of patient-specific surgical devices, simulation, and training. While there are multiple review articles describing utilization of 3D printing in various disciplines, there is paucity of literature addressing applications of 3D printing in breast cancer management. Herein, we review the current applications of 3D printing in breast cancer management and discuss the potential impact on future practices.

The Use of a 3D Simulator Software and 3D Printed Biomodels to Aid Autologous Breast Reconstruction

Aesthetically pleasing and symmetrical breasts are the goal of reconstructive breast surgery. However, multiple procedures are sometimes needed to improve a reconstructed breast's symmetry and appearance. Since all breasts vary in terms of volume, height, width, projection, orientation, and shape, the lack of attention to these details at the moment of flap shaping in autologous reconstruction can lead to poor results. Recent advances in 3-dimensional (3D) surface imaging and printing technologies have allowed for improvement in autologous breast reconstruction symmetry. While 3D printing technology is becoming faster, more accurate, and less expensive, the technology required to obtain proper 3D breast images remains expensive, including laser scanners or 3D photogrammetric cameras. In this study, we present a novel use of an aesthetic surgery simulator software as an affordable alternative to obtaining 3D breast images and creating 3D printed biomodels to aid in the precise shaping of the flap. This approach aims to optimize aesthetic results in autologous breast reconstruction avoiding surgical revisions and reducing surgical times. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The utility of three-dimensional models in complex microsurgical reconstruction

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

Use of 3D print model improves accuracy of preoperative planning and reduces flap harvest time with similar postoperative complications in complex microsurgical reconstruction.