Preoperative implant selection for unilateral breast reconstruction using 3D imaging with the Microsoft Kinect sensor

Sensor technology and machine learning to guide clinical decision making in plastic surgery

Subjective clinical evaluations are deeply rooted in medical practice. Recent advances in sensor technology facilitate the acquisition of extensive amounts of objective physiological data that can serve as a surrogate for subjective assessments. Along with sensor technology, a branch of artificial intelligence, known as machine learning, has provided decisive advances in several areas of medicine due to its pattern recognition and outcome prediction abilities. The assimilation of machine learning algorithms into sensor technology can substantially improve our current diagnostic and treatment competencies. This review explores available data on the use of sensor technology and machine learning in areas of interest for plastic surgeons, updates current knowledge on the most recent technological advances, and provides a new perspective on the field.

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.

Longitudinal Volume Assessment of Reconstructed Breast Using Three-Dimensional Measurement: How Do DIEP and LD Flap Change Immediately after Surgery?

Background  The deep inferior epigastric perforator (DIEP) and latissimus dorsi (LD) flaps are two widely used autologous breast reconstructions. Despite studies on flap-volume changes, the time of the first measurement is not immediately after surgery. Therefore, this study aimed to investigate the change in volume over time from the immediate postoperative period using a three-dimensional (3D) scanner. Methods  Patients who underwent breast reconstruction with a DIEP or LD flap between October 2019 and December 2020 at Showa University Koto Toyosu Hospital were included. The Kinect 3D scanner was used to measure the reconstructed and healthy breast volumes immediately after surgery and at 1, 3, 6, and 12 months. The control group was the healthy side, and the volumes obtained at each time point and ratios (to the immediate postoperative period) were calculated and analyzed using a linear mixed model. Results  Of the 25 patients and 26 breasts examined, the postoperative increase in volume ratios was statistically significant in the DIEP flap group, except for the sixth month, but decreased significantly in the LD group. Compared with the control group, the volume ratio was significantly higher up to 3 months in the DIEP flap group and decreased significantly after 3 months in the LD flap group. Conclusions  The volume of the LD flap continued to decrease immediately after surgery, whereas the volume of the DIEP flap increased by 10% up to 1M. Therefore, this increase in volume should be taken into consideration in studies where the initial measurements were not taken immediately after surgery.

Development of low-cost and personalized external silicone breast prosthesis produced by additive manufacturing for women who have undergone mastectomy: A pilot study

BACKGROUND

The aim of this study was to develop a low-cost and personalized method for external breast prosthesis production.

METHODS

The projected light method was used for the acquisition of the 3D geometry of the left breast of a healthy 29-year-old woman, 69 kg and 1.69 m. The 3D modeling software Blender was used to make the prosthesis model and mold with adjustments to the model's mesh, such as smoothing, assigning thickness, and creating the walls of the prosthesis mold. Two counter-molds were created. The pieces were manufactured on the 3D printer Stella Lite 3 using polylactic acid filament. Finally, the silicone was pigmented, and the mold was filled.

FINDINGS

Prototype 1 of the prosthesis was produced using a mold without a counter-mold, which resulted in a prosthesis of 495 g, considered heavy compared to traditional prostheses for the same breast size. To solve this issue, a counter-mold with pins was used to produce prototype 2 with a mass of 393 g, 20.6% lighter than prototype 1. Prototype 3 was made with a central-volume counter-mold and presented a mass of 355 g, a reduction of 28.3% compared to prototype 1. The definitive breast prosthesis was made with the pin counter-mold with a different silicone. It has nipple and areola pigmentation and a mass of 294 g, 25.2% lighter than prototype 2.

INTERPRETATION

The results suggest that the projected light method and additive manufacturing are potential tools for developing external breast prostheses, which may improve the health conditions and quality of life of mastectomized women.

Development of Three-Dimensional Breast Scan and Measurement Application Using Laser Imaging Detection and Ranging Sensor on iPhone

SUMMARY

Laser imaging detection and ranging (LiDAR) is a modern three-dimensional (3D) technology that uses a time-of-flight method based on the round-trip time of an infrared laser beam to detect the presence and features of objects. The iPhone 12 Pro is the first smart mobile device with built-in LiDAR sensors. The authors' team developed a software application based on iOS devices with built-in LiDAR sensors for 3D breast scanning and automatically analyzing the breast's geometric measurement. Breast geometry, including midclavicle-to-nipple distance, sternal notch-to-nipple distance, nipple-to-inframammary fold (IMF) distance, distance between nipples, and body circumference on nipple and IMF level were measured using the software application and tapeline. The relative technical error of measurement (rTEM) value was used to calculate the error ratios between the measurements acquired by the software application and those of the tapeline. Good rTEM values ranging from 2.99% to 5.19% were found in the midclavicle-to-nipple distance, sternal notch-to-nipple distance, distance between nipples, nipple-level circumference, and IMF-level circumference. However, there was a poor rTEM value greater than 10% in the nipple-to-IMF distance. The proposed software application using current iOS devices with built-in LiDAR sensors can provide an ideal 3D scanning system that has a low cost burden, good accuracy, portability, and ease of use.

Application of three-dimensional reconstruction technology in dentistry: a narrative review

BACKGROUND

Three-dimensional(3D) reconstruction technology is a method of transforming real goals into mathematical models consistent with computer logic expressions and has been widely used in dentistry, but the lack of review and summary leads to confusion and misinterpretation of information. The purpose of this review is to provide the first comprehensive link and scientific analysis of 3D reconstruction technology and dentistry to bridge the information bias between these two disciplines.

METHODS

The IEEE Xplore and PubMed databases were used for rigorous searches based on specific inclusion and exclusion criteria, supplemented by Google Academic as a complementary tool to retrieve all literature up to February 2023. We conducted a narrative review focusing on the empirical findings of the application of 3D reconstruction technology to dentistry.

RESULTS

We classify the technologies applied to dentistry according to their principles and summarize the different characteristics of each category, as well as the different application scenarios determined by these characteristics of each technique. In addition, we indicate their development prospects and worthy research directions in the field of dentistry, from individual techniques to the overall discipline of 3D reconstruction technology, respectively.

CONCLUSIONS

Researchers and clinicians should make different decisions on the choice of 3D reconstruction technology based on different objectives. The main trend in the future development of 3D reconstruction technology is the joint application of technology.

Clinical assessment of breast symmetry and aesthetic outcome: can 3D imaging be the gold standard?

There is a lack of an accurate standardised objective method to assess aesthetic outcome after breast surgery. In this methodological study, we investigated the intra- and inter-observer reproducibility of breast symmetry and volume assessed using three-dimensional surface imaging (3D-SI), evaluated the reproducibility depending on imaging posture, and proposed a new combined volume-shape-symmetry (VSS) parameter. Images were acquired using the VECTRA XT 3D imaging system, and analysed by two observers using VECTRA Analysis Module. Breast symmetry was measured through the root mean square distance. All women had undergone bilateral risk-reducing mastectomy and immediate breast reconstruction. The reproducibility and correlations of breast symmetry and volume measurements were compared using Bland-Altman's plots and tested with Spearman's rank correlation coefficient. 3D surface images of 58 women were analysed (348 symmetry measurements, 696 volume measurements). The intra-observer reproducibility of breast symmetry measurements was substantial-excellent, the inter-observer reproducibility was substantial, and the inter-posture reproducibility was substantial. For measurements of breast volumes, the intra-observer reproducibility was excellent, the inter-observer reproducibility was moderate-substantial, and the inter-posture reproducibility was substantial-excellent. The intra-observer reproducibility of VSS was excellent while the inter-observer reproducibility was substantial for both observers, independent of posture. There were no statistically strong correlations between breast symmetry and volume differences. The intra-observer reproducibility was found to be substantial-excellent for several 3D-SI measurements independent of imaging posture. However, the inter-observer reproducibility was lower than the intra-observer reproducibility, indicating that 3D-SI in its present form is not a great assessment for symmetry.

Comparison of Nasal Analysis by Photographs (2D) against Low-cost Surface Laser Imaging (3D) and against Computed Axial Tomography Imaging

Introduction In aesthetic surgery, we have a few evaluation tools that numerically and objectively measure the changes we make in patients. This article aimed to evaluate the nasal systematic analysis and compare findings between the three systems of nasal evaluation: photographs 2D, 3D surface imaging with the Kinect system, and 3D CT scan imaging.

Methods We designed a longitudinal and descriptive prospective study with simple non-blind randomization. To compare the systematic nasal analysis between the three methods. If the findings are similar, all three methods would be useful in independent clinical scenarios.

Results A total of 42 observations were included finding a minimum age of 21 with a mean of 28 years old. Also, 64% were female, 93% had adequate facial proportions, and 50% were Fitzpatrick III. For outcome statistics, we found differential nasal deviation between 3D images with a mean of 6.53 mm. While when comparing the nasal dorsum length, we found a statistical significance of p = 0.051. When comparing the nasal dorsum length index, we found no significant difference p = 0.32. Also, we did not find statistical significance when comparing the nasofrontal angle and tip rotation angle p = 1 for both.

Conclusion We found that the population we serve has characteristics of Hispanic mestizo nose. The three methods seem to evaluate systematic nasal analysis in a very similar way, and any of them can be used depending on the scenario and the needs of plastic surgeons.

Is 3-Dimensional Scanning Really Helpful in Implant-Based Breast Reconstruction?: A Prospective Study

BACKGROUND

Breast reconstruction is an integral part of breast cancer treatment, and implant-based breast reconstruction is the most commonly used method worldwide. However, there is still no technique that allows surgeons to predict the volume of the required implant. Although computed tomography and magnetic resonance imaging provide adequate representations of the breast, these procedures are time-consuming, expensive, and expose patients to radiation. Therefore, there is a need for safer, noninvasive alternatives for preoperative breast volume measurements.

PATIENTS AND METHODS

This study is a prospective review of 12 patients with early-stage breast cancer who underwent nipple-sparing mastectomy and immediate breast reconstruction with implants. Preoperatively, the Artec Eva 3D scanner was used to acquire volumetric measurements of the breasts. Intraoperatively, the volume of the mastectomy specimen was measured using the water displacement method. Correlations among the preoperative breast, mastectomy specimen, and estimated and final implant volumes were analyzed through Pearson correlation coefficient. A correction prediction factor of 85% was applied where necessary. Patient and physician satisfaction were evaluated 3 months postoperatively.

RESULTS

Our study found a statistically significant correlation between the preoperative breast volumes measured by the Artec Eva 3D scanner and intraoperative mastectomy specimen volumes (r = 0.6578). There was no correlation between the preoperative breast volumes and final implant volumes, mastectomy specimen volumes and final implant volumes, and estimated implant volumes and final implant volumes.

CONCLUSIONS

Although the Artec Eva 3D scanner can offer relatively accurate measurement of breast volumes, multiple studies still need to be done to determine how these data can be applied to the mastectomy procedure and breast implant selection. It may be more applicable for preoperative planning in breast augmentation surgery. Future surgeons should also take into account that variabilities in natural breast size, tumor size, cancer stage, and in patient and physician preferences all influence the outcome of breast reconstruction surgery.

Predictive value of 3D imaging to guide implant selection in immediate breast reconstruction

Background

Pre-operative estimation of breast mound volume for immediate breast reconstruction is necessary for operative planning, especially in direct-to-implant reconstruction. Our purpose was to investigate the relationship between pre-operative predictions of breast mound weight from 3D imaging and actual mastectomy weight and implant size.

Methods

A retrospective chart review of all patients who had previously undergone nipple-sparing mastectomy (NSM) by a single surgeon was performed. Pre-operative 3D images were reviewed and calculations of breast mound weight were performed by three independent reviewers. Intra-operative mastectomy weight and final implant weight were collected from patient charts. A regression analysis between calculated and actual values was performed.

Results

There were 59 reconstructed breasts included. Pre-operative 3D imaging-guided breast weight calculations were similar across reviewers (R=0.96). Pre-operative calculations of breast weight were 49.4g (SD=134.0) smaller than actual mastectomy specimens. Mastectomy specimens were 41.0g (SD=130.2) smaller than final implant sizes. Thereby, the relationship was as follows: Pre-operative calculated breast weight < actual Mastectomy weight < implant weight. Mastectomy weight and final implant size had linear relationships with pre-operative calculations of breast weight. Formulas for predicting mastectomy weight [mastectomy weight = 63.2 + 0.95 (pre-operative calculated weight)] and implant size [Implant weight = 209.7+ 0.56 (pre-operative calculated weight)] from pre-operative calculations of breast weight were generated.

Conclusions

Three-dimensional scanning technologies may be a useful tool to predict implant sizes for direct-to-implant breast reconstruction. Final implant size was heavier than intra-operative mastectomy weight and pre-operative calculated breast mound weight.

Automated Breast Volume Assessment Derived From Digital Breast Tomosynthesis Images Compared to Mastectomy Specimen Weight and Its Applications in Cosmetic Optimisation

Background: Estimating the size and volume of the breast preoperatively is an important step in surgical planning for many breast procedures such as immediate implant-based breast reconstructions and reduction mammoplasties. Breast volume estimation helps in appropriate implant selection preoperatively.

Objectives: The aim of this study was to objectively evaluate the estimation of breast weight by automatic volumetric breast assessment in digital breast tomosynthesis (DBT) using Quantra™ 2.2 Breast Density Assessment Software (Hologic Inc., Marlborough, Massachusetts, United States). Methods: Breast specimen weight after mastectomy and volume estimated by Quantra software were recorded.

Results: Volume assessment obtained from Quantra software showed a high correlation with actual mastectomy specimen weight, with Pearson’s correlation coefficients of 0.952.

Conclusions: The automated DBT-derived breast volume using the Quantra software is a simple and practical method to assess breast size and weight preoperatively. 

The current progress and critical analysis of three-dimensional scanning and three-dimensional printing applications in breast surgery

Background

Several attempts have been made to develop a tool capable of evaluating breast shape and volume to aid surgical planning and outcome assessment. More recently, newer technologies such as three-dimensional (3D) scanning and 3D printing have been applied in breast assessment. The aim of this study was to review the literature to assess the applicability of 3D scanning and 3D printing in breast surgery.

Methods

A literature search was carried on PubMed, Google Scholar and OVID from January 2000 to December 2019 using the keywords ‘3D’, ‘Three-dimensional’, ‘Three/four dimensions’ and ‘Breast’.

Results

A total of 6564 articles were identified initially; the abstracts of 1846 articles were scanned, and 81 articles met the inclusion criteria and were included in this review. Articles were reviewed and classified according to their aims, study subjects, the software and hardware used, main outcomes and major limitations.

Conclusions

These technologies are fast and easy to use, however, high costs, long processing times and the need for training might limit their application. To incorporate these technologies into standard healthcare, their efficacy and effectiveness must be demonstrated through multiple and rigorous clinical trials.

Prediction of the Ideal Implant Size Using 3-Dimensional Healthy Breast Volume in Unilateral Direct-to-Implant Breast Reconstruction

Background and objectives: There is no consensus regarding accurate methods for assessing the size of the implant required for achieving symmetry in direct-to-implant (DTI) breast reconstruction. The purpose of this study was to determine whether the ideal implant size could be estimated using 3D breast volume or mastectomy specimen weight, and to compare prediction performances between the two variables. Materials and Methods: Patients who underwent immediate DTI breast reconstruction from August 2017 to April 2020 were included in this study. Breast volumes were measured using 3D surface imaging preoperatively and at postoperative three months. Ideal implant size was calculated by correcting the used implant volume by the observed postoperative asymmetry in 3D surface imaging. Prediction models using mastectomy weight or 3D volume were made to predict the ideal implant volume. The prediction performance was compared between the models. Results: A total of 56 patients were included in the analysis. In correlation analysis, the volume of the implant used was significantly correlated with the mastectomy specimen weight (R2 = 0.810) and the healthy breast volume (R2 = 0.880). The mean ideal implant volume was 278 ± 123 cc. The prediction model was developed using the healthy breast volume: Implant volume (cc) = healthy breast volume × 0.78 + 26 cc (R2 = 0.900). The prediction model for the ideal implant size using the 3D volume showed better prediction performance than that of using the mastectomy specimen weight (R2 = 0.900 vs 0.759, p < 0.001). Conclusions: The 3D volume of the healthy breast is a more reliable predictor than mastectomy specimen weight to estimate the ideal implant size. The estimation formula obtained in this study may assist in the selection of the ideal implant size in unilateral DTI breast reconstruction.

Use of Commercial Off-The-Shelf Devices for the Detection of Manual Gestures in Surgery: Systematic Literature Review

Background

The increasingly pervasive presence of technology in the operating room raises the need to study the interaction between the surgeon and computer system. A new generation of tools known as commercial off-the-shelf (COTS) devices enabling touchless gesture–based human-computer interaction is currently being explored as a solution in surgical environments.

Objective

The aim of this systematic literature review was to provide an account of the state of the art of COTS devices in the detection of manual gestures in surgery and to identify their use as a simulation tool for motor skills teaching in minimally invasive surgery (MIS).

Methods

For this systematic literature review, a search was conducted in PubMed, Excerpta Medica dataBASE, ScienceDirect, Espacenet, OpenGrey, and the Institute of Electrical and Electronics Engineers databases. Articles published between January 2000 and December 2017 on the use of COTS devices for gesture detection in surgical environments and in simulation for surgical skills learning in MIS were evaluated and selected.

Results

A total of 3180 studies were identified, 86 of which met the search selection criteria. Microsoft Kinect (Microsoft Corp) and the Leap Motion Controller (Leap Motion Inc) were the most widely used COTS devices. The most common intervention was image manipulation in surgical and interventional radiology environments, followed by interaction with virtual reality environments for educational or interventional purposes. The possibility of using this technology to develop portable low-cost simulators for skills learning in MIS was also examined. As most of the articles identified in this systematic review were proof-of-concept or prototype user testing and feasibility testing studies, we concluded that the field was still in the exploratory phase in areas requiring touchless manipulation within environments and settings that must adhere to asepsis and antisepsis protocols, such as angiography suites and operating rooms.

Conclusions

COTS devices applied to hand and instrument gesture–based interfaces in the field of simulation for skills learning and training in MIS could open up a promising field to achieve ubiquitous training and presurgical warm up.

Nonrigid reconstruction of 3D breast surfaces with a low-cost RGBD camera for surgical planning and aesthetic evaluation

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A nonrigid 3D breast surface reconstruction pipeline running on a standard PC taking a noisy RGBD input video from a Kinect-style camera is proposed.

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Pairwise nonrigid ICP is extended to the multi-view case incorporating soft mobility constraints in areas of non-overlap.

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Shortest distance correspondences as a new technique for data association are shown to lead to consistently better alignment.

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The method is able to reconstruct clinical-quality surface models in spite of varying degrees of postural sway during data capture.

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Landmark and volumetric quantitative validation in metric units demonstrate improved reconstruction quality on par with the gold standard and superior to a competing method.

Accounting for 26% of all new cancer cases worldwide, breast cancer remains the most common form of cancer in women. Although early breast cancer has a favourable long-term prognosis, roughly a third of patients suffer from a suboptimal aesthetic outcome despite breast conserving cancer treatment. Clinical-quality 3D modelling of the breast surface therefore assumes an increasingly important role in advancing treatment planning, prediction and evaluation of breast cosmesis. Yet, existing 3D torso scanners are expensive and either infrastructure-heavy or subject to motion artefacts. In this paper we employ a single consumer-grade RGBD camera with an ICP-based registration approach to jointly align all points from a sequence of depth images non-rigidly. Subtle body deformation due to postural sway and respiration is successfully mitigated leading to a higher geometric accuracy through regularised locally affine transformations. We present results from 6 clinical cases where our method compares well with the gold standard and outperforms a previous approach. We show that our method produces better reconstructions qualitatively by visual assessment and quantitatively by consistently obtaining lower landmark error scores and yielding more accurate breast volume estimates.

Infrared Light Structured Sensor Three-dimensional Approach to Estimate Kidney Volume: A Validation Study

OBJECTIVE

To validate a new procedure for the three-dimensional estimation of total renal parenchyma volumeusing a structured-light infrared laser sensor.

METHODS

To evaluate the accuracy of the sensor for assessing renal volume, we performed 3 experiments. Twenty freshly excised porcine kidneys were obtained. Experiment A, the water displacement method was used to obtain a determination of the renal parenchyma volume after immersing every kidney into 0.9% saline. Thereafter a structured sensor (Occipital, San Francisco, CA) was used to scan the kidney. Kidney sample surface was presented initially as a mesh and then imported into MeshLab (Visual Computing Lab, Pisa, Italy) software to obtain the surface volume. Experiment B, a partial excision of the kidney with measurement of the excised volume and remnant was performed. Experiment C, a renorrhaphy of the remnant kidney was performed then measured. Bias and limits of agreement (LOA) were determined using the Bland-Altman method. Reliability was assessed using the intraclass correlation coefficient (ICC).

RESULTS

Experiment A, the sensor bias was -1.95mL (LOA: -19.5 to 15.59, R² = 0.410) with slightly overestimating the volumes. Experiment B, remnant kidney after partial excision and excised kidneyvolume were measured showing a sensor bias of -0.5mL (LOA -5.34 to 4.20, R²= 0.490) and -0.6mL (LOA: -1.97.08 to 0.77, R² = 0.561), respectively. Experiment C, the sensor bias was -0.89mL (LOA -12.9 to 11.1, R²= 0.888). ICC was 0.9998.

CONCLUSION

The sensor is a reliable method for assessing total renal volume with high levels of accuracy.

Chances and limitations of a low-cost mobile 3D scanner for breast imaging in comparison to an established 3D photogrammetric system

BACKGROUND

In search of new possibilities in 3D surface imaging, several nonmedical scanning systems have been assessed for their implementation in plastic surgery. The aim of this study was to compare a new affordable 3D imaging consumer product with an established medical 3D imaging system for objective 3D breast imaging.

METHOD

We compared a low-cost mobile, handheld scanner against an established medical 3D surface imaging system. Forty-two female patients who underwent different types of breast surgery were captured in a 3D view with both devices. Digital breast measurement, volume measurement, and breast surface-to-surface analysis were done using Mirror software. Repeatability was assessed by repeated 3D scans of the torso and surface-to-surface analysis.

RESULTS

Digital breast measurement showed low differences with good-to-excellent correlation between both devices. Mean breast volume difference was small (-5.11 ± 32.10 mL) within the 95% limits of agreement. Surface-to-surface analysis yielded a higher surface deviation in the lower breast quadrants (1.62 ± 0.80 mm root mean square [RMS] error and 1.81 ± 0.88 mm RMS error) than in the upper breast quadrants. Repeatability was satisfactory with a mean of 0.636 ± 0.279 mm RMS error.

CONCLUSION

Affordable mobile surface scanners may offer new perspectives in the future for 3D breast imaging. Although surface acquisition was sufficient for breast measurements in comparison to an established system, the lack of appropriate medical software for patient consultation next to moderate texture quality needs to be improved for wider acceptance in plastic surgery.