Three-Dimensional Imaging of the Chest Wall: A Comparison Between Three Different Imaging Systems.

BACKGROUND: Three-dimensional (3D) imaging is being used progressively to create models of patients with anterior chest wall deformities. Resulting models are used for clinical decision-making, surgical planning, and analysis. However, given the broad range of 3D imaging systems available and the fact that planning and analysis techniques are often only validated for a single system, it is important to analyze potential intrasystem and intersystem differences. The objective of this study was to investigate the accuracy and reproducibility of three commercially available 3D imaging systems that are used to obtain images of the anterior chest wall. METHODS: Among 15 healthy volunteers, 3D images of the anterior chest wall were acquired twice per imaging device. Reproducibility was determined by comparison of consecutive images acquired per device while the true accuracy was calculated by comparison of 3D image derived and calipered anthropometric measurements. A maximum difference of 1.00 mm. was considered clinically acceptable. RESULTS: All devices demonstrated statistically comparable (P = 0.21) reproducibility with a mean absolute difference of 0.59 mm. (SD: 1.05), 0.54 mm. (SD: 2.08), and 0.48 mm. (SD: 0.60) for the 3dMD, EinScan Pro 2X Plus, and Artec Leo, respectively. The true accuracy was, respectively, 0.89 mm. (SD: 0.66), 1.27 mm. (SD: 0.94), and 0.81 mm. (SD: 0.71) for the 3dMD, EinScan, and Artec device and did not statistically differ (P = 0.085). CONCLUSIONS: Three-dimensional imaging of the anterior chest wall utilizing the 3dMD and Artec Leo is feasible with comparable reproducibility and accuracy, whereas the EinScan Pro 2X Plus is reproducible but not clinically accurate.

The inter-rater and test-retest reliability of skin thickness and skin elasticity measurements by the DermaLab Combo in healthy participants.

BACKGROUND: For several purposes, skin parameters like thickness and elasticity can be measured. However, little is known about the accuracy of those measurements. AIM: The aim of this study was to determine the intrarater and test-retest reliability of skin thickness and elasticity measurements performed with the DermaLab Combo®. METHODS: A total of 49 participants were included in this study. Skin thickness and elasticity were measured at six defined locations on the dominant arm. Measurements were repeated two times by the same observer to determine the test-retest reliability. To determine the inter-rater reliability, a second observer repeated the measurements once. RESULTS: Inter-rater and test-retest reliability for elasticity measurements fluctuates per location and per parameter: Inter-rater intraclass correlation coefficient (ICC) ranged from 0.23 to 0.80, and test-retest ICC ranged from 0.25 to 0.84. Skin thickness was measured reliable by every observer on every location, with a test-retest ICC ranging from 0.71 to 0.83 and an inter-rater ICC ranging from 0.69 to 0.80. CONCLUSION: The DermaLab Combo® showed a good inter-rater reliability when measuring skin thickness and elasticity. Not all locations are suitable for reliable inter-rater or test-retest measurements. The device is difficult to use by inexperienced users, as the echo probe is sensitive to small movements.

The Long-term Patency of Lymphaticovenular Anastomosis in Breast Cancer-Related Lymphedema.

BACKGROUND AND OBJECTIVES: Lymphedema is a condition that can greatly affect patient's quality of life. Promising results have been described with lymphaticovenular anastomosis (LVA) in the treatment of lymphedema. It is currently unknown at what rate anastomoses remain functional after a longer follow-up. The aim of this study was to determine LVA patency at 1-year follow-up. METHODS: Retrospective chart review was performed on patients who underwent LVA surgery. Patients who had indocyanine green lymphography performed at 12 months' follow-up after LVA were included in this study. Volume measurements were performed prior to surgery and at 6 and 12 months' follow-up. Patients quality of life was measured prior to surgery and at 6 months' follow-up. RESULTS: Twelve patients met inclusion criteria. In total, 15 (56.5%) of 23 LVAs were considered patent. In 8 patients (66.7%), at least 1 patent LVA was visible. The volume difference between the healthy and affected arms decreased 32.3% on average. Quality of life increased with 1.4 points on average. CONCLUSIONS: This study is, to our knowledge, the first to evaluate long-term patency of LVA in upper limb lymphedema. Our study demonstrates that at least 56.5% of the anastomoses created are patent after 1-year follow-up.

3D-printed prostheses in developing countries: A systematic review.

BACKGROUND: According to the World Health Organization, only 5%-15% of people in lower-income countries have access to prostheses. This is largely due to low availability of materials and high costs of prostheses. 3D-printing techniques have become easily accessible and can offer functional patient-specific components at relatively low costs, reducing or bypassing the current manufacturing and postprocessing steps. However, it is not yet clear how 3D-printing can provide a sustainable solution to the low availability of limb prostheses for patients with amputations in lower-income countries. OBJECTIVE: To evaluate 3D-printing for the production of limb prostheses in lower-income countries and lower-middle-income countries (LLMICs). STUDY DESIGN: Systematic Review. METHODS: Literature searches, completed in April 2020, were performed in PubMed, Embase, Web of Science, and Cochrane Library. The search results were independently screened and reviewed by four reviewers. Only studies that examined interventions using prostheses in LLMICs for patients with limb amputations were selected for data extraction and synthesis. The web was also searched using Google for projects that did not publish in a scientific journal. RESULTS: Eighteen studies were included. Results were reported regarding country of use, cost and weight, 3D-printing technology, satisfaction, and failure rate. CONCLUSION: Low material costs, aesthetic appearance, and the possibility of personalized fitting make 3D-printed prostheses a potential solution for patients with limb amputations in LLMICs. However, the lack of (homogeneous) data shows the need for more published (scientific) research to enable a broader availability of knowledge about 3D-printed prostheses for LLMICs.

Improving Lives in Three Dimensions: The Feasibility of 3D Printing for Creating Personalized Medical Aids in a Rural Area of Sierra Leone.

The aim of this feasibility study was to investigate how a 3D printer could be put to its best use in a resource-limited healthcare setting. We have examined whether a 3D printer can contribute to making prostheses, braces, or splints for patients who underwent major limb amputation because of complex wounds, for example, due to burns and subsequent scarring, accidents, conflicts, or congenital abnormalities. During a 3-month period, we investigated the benefits of customized, 3D-printed arm prostheses, splints, and braces in Sierra Leone. Using a handheld 3D scanner and a 3D printer, patient-specific medical aids were designed, manufactured, and tested. Questionnaires regarding patient satisfaction and the functionality of the prostheses were used for a short-term follow-up. Four esthetic prostheses were designed: two prostheses of the hand, one of the forearm, and one of the entire arm. Follow-ups were conducted after 3 to 4 weeks to investigate the quality of the prostheses and to complete a patient questionnaire. Even though the prostheses primarily fulfill esthetic needs, they also exhibit some degree of functionality. In addition, four splints for hands and arms were made to prevent scar contractures after skin transplantation. Finally, a brace for a young boy with kyphoscoliosis was manufactured. The boy has accepted the brace and will be followed up in the months to come. Long-term follow-up is required to prove the sustainability of the 3D-printed brace and prosthetic arms. Further research into how to sustain and refine this project is underway.

Applications and limitations of using patient-specific 3D printed molds in autologous breast reconstruction.

BACKGROUND: Over the last years, several techniques have been proposed to improve the outcome of autologous breast reconstruction procedures. One of these innovations describes patient-specific, three-dimensional (3D) printed breast molds for intraoperative use based on 3D stereophotogrammetry. In this article, we want to share our preliminary experiences with producing such templates, its clinical possibilities and limitations in practice. METHODS: Patient-specific templates were designed based on 3D stereophotogrammetry images. The 3D template was fabricated using a 3D printer. During breast reconstruction, the autologous flap was placed inside the printed template to aid the surgeon in determining the shape and volume of the autologous flap creating the desired breast dimensions. Patients were 3D-photographed 6 to 9 months post-operatively. RESULTS: Three patients with unilateral breast reconstructions showed a width difference of 0.5 cm and mean volume difference of 211 ml between the reconstructed and contralateral breasts. In the three bilateral reconstructed patients, a mean difference in breast width and volume of respectively 0.5 cm and 16 ml was found. CONCLUSIONS: Patient-specific breast templates are inexpensive and relatively easy to design, while being practical and convenient to obtain insight in the dimensions of the desired breast during reconstruction, according to the operating surgeons. Patient selection is however critical, as patients must have sufficient donor volume and/or satisfying breast shape to be able to use the template to its full potential.Level of evidence: Level IV, therapeutic study.

Accuracy of Three Software Applications for Breast Volume Calculations from Three-Dimensional Surface Images.

BACKGROUND: Knowing breast volumes before certain surgeries helps the surgeon to obtain breast symmetry. Calculating breast volumes from three-dimensional surface images is possible with specialized software applications. However, limited data exist concerning the accuracy of such volume calculations. The purpose of this study was to investigate the accuracy of breast volume calculations performed with the 3D BreAST, 3dMD Vultus, and VECTRA software applications. METHODS: Twenty-six subjects who underwent 44 mastectomies were enrolled. Preoperative three-dimensional surface images were acquired with a VECTRA-XT stereophotogrammetry device. Breast volumes were calculated from these images with the three software applications. The mastectomy specimens were weighed to derive their actual volume and compared with the software calculations. RESULTS: For all three methods, a positive correlation between the breast volume and absolute calculation error was found (p < 0.001), but not for the errors as a percentage of the breast volume (p = 0.17, p = 0.80, and p = 0.42). The 3D BreAST, 3dMD Vultus, and VECTRA applications provided mean volume calculation errors of 21, 186, and -32 ml (p = 0.27, p < 0.001, and p = 0.14) or 2 ± 25, 48 ± 26, and -6 ± 27 percent of the breast volume (p = 0.67, p < 0.001, and p = 0.16), respectively. CONCLUSIONS: Despite that two applications calculated accurate mean breast volumes, all applications showed a high standard deviation in terms of the percentage of the breast volume. Therefore, the usefulness of absolute breast volume calculations from three-dimensional surface images seems limited. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.

Virtual Incision Pattern Planning using Three-Dimensional Images for Optimization of Syndactyly Surgery.

Syndactyly is a congenital condition characterized by fusion of the fingers. If not treated correctly during infancy, syndactyly may hinder the normal development of hand function. Many surgical techniques have been developed, with the main goal to create a functional hand with the smallest number of operative corrections. Therefore, exact preoperative planning of the reconstructive procedure is essential. An imaging method commonly used for preoperative planning is 3-dimensional (3D) surface imaging. The goal of this study was to implement the use of this technique in hand surgery, by designing a virtual planning tool for a desyndactylization procedure based on 3D hand images. A 3D image of a silicon syndactyly model was made on which the incision pattern was virtually designed. A surgical template of this pattern was printed, placed onto the silicon model and delineated. The accuracy of the transfer from the virtual delineation toward the real delineation was calculated, resulting in a mean difference of 0.82 mm. This first step indicates that by using 3D images, a virtual incision pattern can be created and transferred back onto the patient successfully in an easy and accurate way by using a template. Thereafter, 3D hand images of 3 syndactyly patients were made, and individual virtual incision patterns were created. Each pattern was transferred onto the patient by using a 3D printed template. The resulting incision pattern needed minor modifications by the surgeon before the surgery was performed. Further research and validation are necessary to develop the virtual planning of desyndactylization procedures.

An innovative method of planning and displaying flap volume in DIEP flap breast reconstructions.

BACKGROUND: Determining the ideal volume of the harvested flap to achieve symmetry in deep inferior epigastric artery perforator (DIEP) flap breast reconstructions is complex. With preoperative imaging techniques such as 3D stereophotogrammetry and computed tomography angiography (CTA) available nowadays, we can combine information to preoperatively plan the optimal flap volume to be harvested. In this proof-of-concept, we investigated whether projection of a virtual flap planning onto the patient's abdomen using a projection method could result in harvesting the correct flap volume. METHODS: In six patients (n = 9 breasts), 3D stereophotogrammetry and CTA data were combined from which a virtual flap planning was created comprising perforator locations, blood vessel trajectory and flap size. All projected perforators were verified with Doppler ultrasound. Intraoperative flap measurements were collected to validate the determined flap delineation volume. RESULTS: The measured breast volume using 3D stereophotogrammetry was 578 ± 127 cc; on CTA images, 527 ± 106 cc flap volumes were planned. The nine harvested flaps weighed 533 ± 109 g resulting in a planned versus harvested flap mean difference of 5 ± 27 g (flap density 1.0 g/ml). In 41 out of 42 projected perforator locations, a Doppler signal was audible. CONCLUSION: This proof-of-concept shows in small numbers that flap volumes can be included into a virtual DIEP flap planning, and transferring the virtual planning to the patient through a projection method results in harvesting approximately the same volume during surgery. In our opinion, this innovative approach is the first step in consequently achieving symmetric breast volumes in DIEP flap breast reconstructions.

3D stereophotogrammetry in upper-extremity lymphedema: An accurate diagnostic method.

BACKGROUND: Upper-extremity lymphedema is a frequent complication in patients treated for breast cancer. Current diagnostic methods for the upper-extremity volume measurements are cumbersome or time consuming. The purpose of this study was to assess the validity and reliability of three-dimensional (3D) stereophotogrammetry for volume measurements in patients with upper-extremity lymphedema. METHOD: Patients with unilateral upper-extremity lymphedema were included. The water displacement volume measurement of both arms was performed using a standardized method. In addition, 3D stereophotogrammetry volume measurements were conducted. RESULTS: Eleven patients (22 arms) were included. The mean volumes obtained by 3D stereophotogrammetry and water displacement show a high correlation, with a Pearson's correlation coefficient of 0.99 (p = 0.01). The variance calculated by 3D stereophotogrammetry measurements (205 mL) was statistically significant less than that obtained via water displacement measurements (1540 mL) (p < 0.001). CONCLUSION: 3D stereophotogrammetry is an accurate method for measuring upper-extremity volume in patients with lymphedema and gives a lower variance value compared to that of the water displacement measurements. We recommend the use of this method in the diagnosis and follow-up of patients with lymphedema.

An analysis of pose in 3D stereophotogrammetry of the breast.

BACKGROUND: Volume of the breast can be objectively measured by three-dimensional (3D) photographs. This study describes the analysis of three different positions of the patient in image acquisition, in order to find the best pose for reproducible 3D photographs of the breasts. METHOD: Twenty-four patients were included between February and September 2014 in a consecutive way. Data were collected prospectively. 3D photographs were acquired using a stereophotogrammetry system. Images were taken twice in three different positions (arms behind the back, arms placed on the hips and arms horizontally placed). Surface based matching was applied and the absolute mean distance between the surfaces of both 3D models of the same position was calculated. This difference measure represents the similarity of the photographs. RESULTS: Univariate ANOVA showed a significant difference in distance between the three positions (sum of squares 1.12, p < 0.001). The horizontal position presented the lowest absolute mean distance (0.45 mm). Additional post hoc multiple comparisons analysis revealed a statistically significant difference between the distances of horizontal and back position (-0.22 mm, p < 0.001) and of back and hip position (0.13 mm, p = 0.009), with better results of the horizontal and hip positions, respectively. CONCLUSION: Standardization of 3D acquisition in pre- and postoperative breast imaging could improve imaging reproducibility. Based on the results of this study, we recommend a pose with the arms in a horizontal position.

Accuracy of virtually 3D planned resection templates in mandibular reconstruction.

OBJECTIVE: Since reconstruction of composite defects in the head and neck region is a challenging and demanding problem for head and neck surgeons, surgical aids have been sought for decades. The purpose of this study was to evaluate the accuracy of prefabricated surgical resection templates used in mandibular segmental resections in comparison to the virtual surgical plan. MATERIALS AND METHODS: A prospective study was performed in 11 consecutive patients, with a primary T4 oral squamous cell carcinoma or osteoradionecrosis of the mandible. Preoperatively, a CBCT scan was acquired to delineate the size and extension of tumor invasion; a virtual patient-specific resection template was designed based on this information. Intraoperatively, the resection template was positioned on the mandible and secured using four fixation screws. Postoperatively, a CBCT scan was acquired. This scan was superimposed on the preoperative scan. Positioning of the resection template and inclination of the resection planes were evaluated on the virtual head model. In order to test the interobserver reliability of these new measurement methods, two different observers executed all measurements. RESULTS: The mean shift of the proximal resection templates was 3.76 mm (standard deviation [SD] 3.10 mm). For the distal resection templates, the mean shift was 3.06 mm (SD 1.57 mm) with no significant interobserver difference (ICC = 0.99). An absolute mean deviation of 8.5° (SD 5.3°) was found for the proximal resection angle and 10.4° (SD 5.0°) for the distal resection angle. Again, no significant interobserver differences were found (ICC = 0.98). CONCLUSION: The resection templates used in this study proved reasonably accurate. Although the concept of virtual surgical planning aids significantly in mandibular reconstruction with microvascular free flaps, further improvement of resection accuracy is necessary for further improvement of reconstruction accuracy.