Three-dimensional imaging: a novel, valid, and reliable technique for measuring wound surface area

A clinimetric assessment of the validity and reliability of 3D technology for scar surface area measurement

INTRODUCTION

The quality of scars has become an important outcome of burn care. Objective scar assessment through scar surface area measurement enables quantification of scar formation and evaluation of treatment efficacy. 3D technology has proven valid and reliable but often remains cumbersome, expensive, and time-consuming. 3D technology with depth sensors on mobile devices has become available and might surpass these limitations. This study provides a clinimetric assessment of the validity and reliability of a 3D system with a depth sensor for scar surface area measurement.

METHODS

A technology involving a depth sensor mounted on a mobile device was used. Images and analyses were made with a custom-made software application. A standardized one-keyframe image capturing procedure was followed. To assess validity, stickers with predefined dimensions (8.01 cm² - 77.70 cm²) were imaged in a single observer setting on various body parts of healthy volunteers. To assess reliability, hypertrophic scars, keloids, and normotrophic scars were imaged and rated by two observers independently. Data are expressed as mean (+/-SD), Coefficient of Variation (CV), Intraclass Correlation Coefficients (ICC), and Limits of Agreements (LoA).

RESULTS

Eighty stickers placed on 20 healthy volunteers showed validity with CV between 0.62%- 1.67% for observer A and 0.75%- 1.19% for observer B. For the reliability study, 69 scars on 36 patients were included. Mean scar surface area ranged from 0.83 cm² to 155.59 cm². Mean scar surface area measurement was 13.83 cm² (SD 23.06) for observer A and 13.59 cm² (SD 23.31) for observer B. Adjusted interobserver CV for trained observers is estimated as 5.59%, with corresponding LoA = 0 ± 0.15 x mean surface area. Interobserver ICCs were 0.99-1.00.

CONCLUSION

This 3D technology with a depth sensor for measuring scar surface area provides valid and reliable data and thereby surpasses expensive and time-consuming 3D cameras.

An evaluation of three-dimensional facial changes after surgically assisted rapid maxillary expansion (SARME): an observational study

BACKGROUND

The abnormal facial features in maxillary transverse deficiency (MTD) are minimal and limited to a deficiency of the middle facial third, narrow nares and nasal base, and deepened nasolabial folds. The surgical expansion of the narrow maxilla has most obvious effects on widening of the maxillary dental arch and expansion of the maxillary and palatal structures in the transverse plane, however sagittal changes also occurs. The purpose of this observational study was to evaluate the three-dimensional (3D) facial soft tissue changes following surgically assisted rapid maxillary expansion (SARME).

METHODS

In 15 skeletally mature patients with severe maxillary transverse deficiency, the planned maxillary expansion (on average 8.8 mm ± 2.3 mm) was achieved with a bone-borne palatal distractor. The 3D optical scans of the facial surface were obtained before and six months after SARME. In the first part, we defined different anatomical landmarks on both scans and compared cephalometric measurements. In the second part, we registered both 3D scans in the same workplace using the regional best-fit method (forehead, supraorbital and nasal root regions were selected for the superimposition) and conducted surface analysis.

RESULTS

The largest differences between the pre- and post-operation scans were observed in the paranasal and cheek area (1.4 ± 1.0 mm). Significant differences occurred for an increased nasal width, a decreased upper-face height with an unchanged lower height, an increased vertical philtrum height and an increased nasolabial angle. A significant increase in the facial profile angle was also observed, resulting in an increased facial convexity and anterior displacement of the upper-lip area.

CONCLUSIONS

The widening of the nose and increased projection in the cheek and paranasal area in the lateral direction after maxillary expansion were confirmed; moreover, facial convexity increases, reflecting the underlying advancement of the maxilla.

3D-printed models improve surgical planning for correction of severe postburn ankle contracture with an external fixator

Gradual distraction with an external fixator is a widely used treatment for severe postburn ankle contracture (SPAC). However, application of external fixators is complex, and conventional two-dimensional (2D) imaging-based surgical planning is not particularly helpful due to a lack of spatial geometry. The purpose of this study was to evaluate the surgical planning process for this procedure with patient-specific three-dimension-printed models (3DPMs). In this study, patients coming from two centers were divided into two cohorts (3DPM group vs. control group) depending on whether a 3DPM was used for preoperative surgical planning. Operation duration, improvement in metatarsal-tibial angle (MTA), range of motion (ROM), the American Orthopedic Foot and Ankle Society (AOFAS) scores, complications, and patient-reported satisfaction were compared between two groups. The 3DPM group had significantly shorter operation duration than the control group ((2.0±0.3) h vs. (3.2±0.3) h, P<0.01). MTA, ROM, and AOFAS scores between the two groups showed no significant differences pre-operation, after the removal of the external fixator, or at follow-up. Plantigrade feet were achieved and gait was substantially improved in all patients at the final follow-up. Pin-tract infections occurred in two patients (one in each group) during distraction and were treated with wound care and oral antibiotics. Patients in the 3DPM group reported higher satisfaction than those in the control group, owing to better patient-surgeon communication. Surgical planning using patient-specific 3DPMs significantly reduced operation duration and increased patient satisfaction, while providing similar improvements in ankle movement and function compared to traditional surgical planning for the correction of SPAC with external fixators.

Application of Contrast-Enhanced Real-time 3-Dimensional Ultrasound in Solid Abdominal Organ Trauma

OBJECTIVES

To determine whether real-time 3-dimensional ultrasound (RT3DUS) could provide additional information on early detection and evaluation in the management of solid abdominal organ trauma based on an animal model.

METHODS

Nine bleeding lesions were developed in the livers (n = 3), kidneys (n = 3), and spleens (n = 3) from 9 pigs. An ultrasound contrast agent was administered intravenously (liver, 0.025 mL/kg; kidney, 0.008 mL/kg; and spleen, 0.013 mL/kg) after an unenhanced 2-dimensional ultrasound (2DUS) examination (B-mode and color Doppler). After contrast agent injection, bleeding lesions were imaged by 2DUS and sequentially imaged by 3-dimensional static ultrasound (3DSUS) and RT3DUS to identify active bleeding, observe the relationship between bleeding lesions and peripheral blood vessels, and evaluate the spatial scope of the bleeding lesions in the organs.

RESULTS

For the identification of active bleeding, there was no statistical difference in contrast-enhanced 2DUS, 3DSUS, and RT3DUS. For observation of the relationship between bleeding lesions and peripheral blood vessels, RT3DUS performed statistically better than 2DUS (P < .05), as reconstructed RT3DUS could show more information about the relationship. For the evaluation of the spatial scope of the bleeding lesion in the organ, RT3DUS also performed statistically better than 2DUS from the multiplanar observation by postprocessing of the 3-dimensional real-time volumes (P < .05).

CONCLUSIONS

Real-time 3-dimensional ultrasound improves early detection and evaluation of solid abdominal organ trauma and provides additional information over the current contrast-enhanced 2DUS.

Application of 3D Printed Models of Complex Hypertrophic Scars for Preoperative Evaluation and Surgical Planning

Background

Complex hypertrophic scar is a condition that causes multiple joint contractures and deformities after trauma or burn injuries. Three-dimensional (3D) printing technology provides a new evaluation method for this condition. The objective of this study was to print individualized 3D models of complex hypertrophic scars and to assess the accuracy of these models.

Methods

Twelve patients with complex hypertrophic scars were included in this study. Before surgery, each patient underwent a computed tomography (CT) scan to obtain cross-sectional information for 3D printing. Mimics software was used to process the CT data and create 3D printed models. The length, width, height, and volume measurements of the physical scars and 3D printed models were compared. Experienced surgeons used the 3D models to plan the operation and simulate the surgical procedure. The hypertrophic scar was completely removed for each patient and covered with skin autografts. The surgical time, bleeding, complications, and skin autograft take rate were recorded. All patients were followed up at 12 months. The surgeons, young doctors, medical students, and patients involved in the study completed questionnaires to assess the use of the 3D printed models.

Results

The 3D models of the hypertrophic scars were printed successfully. The length, width, height, and volume measurements were significantly smaller for the 3D printed models than for the physical hypertrophic scars. Based on preoperative simulations with the 3D printed models, the surgeries were performed successfully and each hypertrophic scar was completely removed. The surgery time was shortened and the bleeding was decreased. On postoperative day 7, there were two cases of subcutaneous hemorrhage, one case of infection and one case of necrosis. On postoperative day 12, the average take rate of the skin autografts was 97.75%. At the 12-month follow-up, all patients were satisfied with the appearance and function.

Conclusion

Accurate 3D printed models can help surgeons plan and perform successful operations, help young doctors and medical students learn surgical methods, and enhance patient comprehension and confidence in their surgeons.

Incorporation of 3D stereophotogrammetry as a reliable method for assessing scar volume in standard clinical practice

Significant disfigurement and dysfunction is caused by hypertrophic scarring, a prevalent complication of burn wounds. A lack of objective tools in the assessment of scar parameters makes evaluation of scar treatment modalities difficult. 3D stereophotogrammetry, obtaining measurements from 3D photographs, represents a method to quantitate scar volume, and a 3D camera may have use in clinical practice. To validate this method, scar models were created and photographed with a 3D camera. Measurements from 3D image analysis of these scar models were compared to physical measurements of scar model volume. Reliability of 3D image analysis was assessed with both scar models and burn patient scars. Measurements of scar models by two independent observers were compared to determine inter-rater reliability, and measurements from 3D images of burn patient hypertrophic scars were compared to determine the consistency of the method between observers. The time taken for patient photography was recorded. No significant differences were found between the two methods of volume calculation (p = 0.89), and a plot of the differences showed agreement between the methods. The correlation coefficient between the two observers' measurements of scar model volume was 0.92, and the intra-class correlation coefficient for patient scar volume was 0.998, showing good reliability. The time required to capture 3D photographs ranged from 2 to 6 min per patient, showing the potential for this tool to be efficiently incorporated into clinical practice. 3D stereophotogrammetry is a valid method to reliably measure scar volume and may be used to objectively measure efficacy of scar treatment modalities to track scar development and resolution.

Three-dimensional imaging is a novel and reliable technique to measure total body surface area

OBJECTIVE

The aim of this study was to explore the diverse clinimetric aspects of three-dimensional imaging measurements of TBSA in clinical practice compared with the methods currently used in clinical practice (i.e., the rule of nines and palm method) to measure TBSA in clinical practice.

METHOD

To assess reliability, two independent researchers measured the TBSAs of 48 burn patients using Artec MHT™ Scanner and software. Subsequently, a resident and burn specialist estimated the TBSA of the same wounds using the rule of nines and palm method.

RESULTS

Three-dimensional imaging showed excellent inter-observer reliability, with an intra-class correlation coefficient (ICC) of 0.99, standard error of measurement (SEM) of 0.054, and limits of agreement (LoA) of ±0.15×the mean TBSA (between the measurements of two researchers). The inter-observer reliability of the methods used in current clinical practice was less reliable, with an ICC of 0.91, SEM of 0.300 and LoA of ±0.78×the mean TBSA. The inter-observer reliability was least reliable between three-dimensional imaging and the residents compared with the burn specialists for the estimated TBSA, with an ICC of 0.68, SEM of 0.69 and LoA of ±1.49×the mean TBSA.

CONCLUSION

The inter-observer reliability of three-dimensional imaging was superior compared with the rule of nines and palm method.