Evolution of 3D surface imaging systems in facial plastic surgery

Recent advancements in computer technologies have propelled the development of?3D imaging systems. 3D surface-imaging is taking surgeons to a new level of communication with patients; moreover, it provides quick and standardized image documentation. This article recounts the chronologic evolution of 3D surface imaging, and summarizes the current status of today's facial surface capturing technology. This article also discusses current 3D surface imaging hardware and software, and their different techniques, technologies, and scientific validation, which provides surgeons with the background information necessary for evaluating the systems and knowledge about the systems they might incorporate into their own practice.     

基于面部三维重建模型设计个性化外壳在面部下颏填充整形术中的应用

目的探讨通过红外线、自然光扫描技术、三维重建技术及快速成形技术制作个性化外壳的方法,为自体脂肪颏部填充术提供客观精确的手术辅助及参考。方法自2018年11月至2019年6月对收治的39例下颏短小患者随机分为对照组(19例)和观察组(20例)。对照组根据医师的临床经验采用传统的自体脂肪填充术;观察组通过手持式三维扫描仪采集患者面部信息重建面部三维模型,并在此基础上设计术后形态,利用三维打印等快速成形技术制作个性化三维透明外壳并消毒备用。行面部填充术时将其置于术区表面,在外壳的引导下手术。术后6个月,使用李克特量表采集两组患者的满意度,使用t检验比较两组术中自体脂肪利用率、患者满意度和手术时间。结果术后6个月与对照组相比,观察组患者达预期整形效果的满意度均高于对照组,其差异具有统计学意义(P<0.05);手术并发症及生活质量满意度比较,其差异无统计学意义(P>0.05)。观察组自体脂肪利用率(平均91%)大于对照组(平均71%),其差异具有统计学意义(P<0.05)。两组手术时间比较,其差异无统计学意义(P>0.05)。术后面部手术效果较好。获随访6个月,无并发症发生。结论制作面部个性化外壳能够更客观地指导自体脂肪颏部填充术,满足患者和医师对个性化的要求,为术后效果评估提供量化依据,同时能提高患者的满意度及自体脂肪利用率。     

The evolution of three-dimensional technology in musculoskeletal oncology

Musculoskeletal tumours pose considerable challenges for the orthopaedic surgeon during pre-operative planning, resection and reconstruction. Improvements in imaging technology have improved the diagnostic process of these tumours. Despite this, studies have highlighted the difficulties in achieving consistent resection free margins especially in tumours of the pelvis and spine when using conventional methods. Three-dimensional technology – three-dimensional printing and navigation technology – while relatively new, may have the potential to prove useful in the musculoskeletal tumour surgeon's arsenal. Three-dimensional printing (3DP) allows the production of objects by adding material layer by layer rather than subtraction from raw materials as performed conventionally. High resolution imaging, computer tomography (CT) and magnetic resonance imaging (MRI), are used to print highly complex and accurate items. Powder-based printing, vat polymerization-based printing and droplet-based printing are the common 3DP technologies applied. 3DP has been utilized pre-operatively in surgical planning and intra-operatively for patient specific instruments and custom made prosthesis. Pre-operative 3DP models transfer information to the surgeon in a concise yet exhaustive manner. Patient specific instruments are customized 3DP instruments utilized with the intention to easily replicate surgical plans. Complex musculoskeletal tumours pose reconstructive challenges and standard implants are often unable to reconstruct defects satisfactorily. The ability to use custom materials and tailor the pore size, elastic modulus and porosity of the 3DP prosthesis to be comparable to the patient's bone allows for a potential patient-specific prosthesis with unique incorporation and longevity properties. Similarly, navigation technology utilizes CT or MRI images to provides surgeons with real time intraoperative three-dimensional calibration of instruments. It has been shown to potentially allow surgeons to perform more accurate resections. These technological advancements have the potential to greatly impact the management of musculoskeletal tumours. 3D planning models, patient-specific instruments and customized 3DP implants and navigation should not be thought of as separate, but rather, patient-specific adaptation of relevant modes of application should be selected on a case-by-case basis when taking all unique factors of each case into consideration.     

Comparison of two-dimensional methods versus three-dimensional scanning systems in the assessment of total body surface area estimation in burn patients

Background

Accurate measurement of percent total body surface area (%TBSA) burn is crucial in the management of burn patients for calculating the estimated fluid resuscitation, determining the need to transfer to a specialized burn unit and probability of mortality. %TBSA can be estimated using many methods, all of which are relatively inaccurate. Three-dimensional (3D) systems have been developed to improve %TBSA calculation and consequently optimize clinical decision-making. The objective of this study was to compare the accuracy of percent total burn surface area calculation by conventional methods against novel 3D methods.

Application of three-dimensional image reconstruction technology based on high-resolution CT in pyeloplasty

BackgroundThree-dimensional (3D) image reconstruction technology is widely used in surgical operations for its intuitive visualization. Pyeloplasty requiresprecise cutting and suturing. The reconstruction technology can accurately determine the location and scope of the stenosis at the junction of the renal pelvis and ureter and the relationship with the surrounding vasculature. The purpose of this article is to retrospective evaluate the application value of image reconstruction technology in pyeloplasty based on high-resolution 3D CT images.MethodsA total of 20 patients with renal pelvic ureteral junction obstruction admitted to our hospital from August 2019 to August 2020 were selected. In this group, left pyeloplasty was performed in 8 patients and right pyeloplasty in 12 patients. In terms of conditions, there was 1 case with secondary pyeloplasty, 6 cases of patients with kidney stones, 2 cases with renal ectopic blood vessels, 1 case with renal prolapse, 1 case with horseshoe kidney, and 1 case with ureteral polyps. There were 12 males and 8 females, with an average age of 34.65±10.67 years and an average body mass index (BMI) of 22.48±3.03 kg/m². In all patients, 3D CT reconstruction technology was used to guide the formulation of robot-assisted laparoscopic pyeloplasty plans; verify the consistency between the actual operation and the preoperative planning; and observe the operation time, blood loss, postoperative exhaust time, indwelling drainage tube time, and follow-up for comorbidities.ResultsThe operation was successful in all 20 patients. The actual operation was 100% consistent with the preoperative planning, the operative time was 160.80±63.26 min, the intraoperative blood loss was 47±30.45 mL, the postoperative exhaust time was 1.15±0.37 days, the drainage tube indwelling time was 4.35±1.50 days, and the average follow-up time was 7.95±3.41 months. There were no complications.ConclusionsThree-dimensional image reconstruction technology based on high-resolution CT has high clinical application value in the treatment of ureteropelvic junction obstruction (UPJO), which simplifies the operation process and shortens the operation time, and is a valuable tool for auxiliary surgeons in devising the operation plan.     

Achieving precision surgery in laparoscopic liver resection with the aid of preoperative three-dimensional reconstruction: A case report

IntroductionThe use of three-dimensional image reconstruction in liver surgery is well-known and has got many applications: It was first developed for vein reconstruction in liver transplantation and for liver volumetry to prevent post hepatectomy liver failure (PHLF) after major resections. There are many other advantages described in the literature provided by three-dimensional reconstruction, however its diffusion is currently limited.Clinical caseWe present the case of a woman with a single colon cancer metastasis in segment 5 of the liver. Using CT scan images we created a three dimensional reconstruction of the patient’s liver and its inners structures. The rendering was used to hypothesize the plan of dissection and to predict the pedicles that needed to be dissected during the procedure.DiscussionWe try to demonstrate that, thanks to three dimensional image reconstruction, all the structures that need to be dissected could be effectively located prior to the the surgery with a high grade of approximation. Furthermore the 3D reconstruction could be used as a step by step guide during the whole surgical procedure, showing all the pedicles To be encountered and dissected at every stage.Conclusion3d reconstruction of the liver is a valid aid in the interpretation of preoperative imaging and intraoperative ultrasound, both for the surgeon and for the entire equipe, facilitating comprehension of patient’s liver anatomical features. It allows to predict the location and direction of the pedicles that need to be dissected and resected with high approximation, in order to achieve a more precise and tailored surgery.     

Evaluation of three-dimensional computed tomography processing for deep inferior epigastric perforator flap breast reconstruction

BACKGROUND:

The deep inferior epigastric perforator flap procedure has become a popular alternative for women who require breast reconstruction. One of the difficulties with this procedure is identifying perforator arteries large enough to ensure that the harvested tissue is well vascularized. Current techniques involve imaging the perforator arteries with computed tomography (CT) to produce a grid mapping the locations of the perforator arteries relative to the umbilicus.

OBJECTIVES:

To compare the time it takes to produce a map of the perforators using either two-dimensional (2D) or three-dimensional (3D) CT, and to see whether there is a benefit in using a 3D model.

METHODS:

Patient CT abdomen and pelvis scans were acquired from a GE 64-slice scanner. CT image processing was performed with the GE 3D Advantage Workstation v4.2 software. Maps of the perforators were generated both as 2D and 3D representations. Perforators within a region 5 cm rostral and 7 cm caudal to the umbilicus were measured and the times to perform these measurements using both 2D and 3D images were recorded by a stopwatch.

RESULTS:

Although the 3D method took longer than the 2D method (mean [± SD] time 1:51±0:35 min versus 1:08±0:16 min per perforator artery, respectively), producing a 3D image provides much more information than the 2D images alone. Additionally, an actual-sized 3D image can be printed out, removing the need to make measurements and producing a grid.

CONCLUSIONS:

Although it took less time to create a grid of the perforators using 2D axial CT scans, the 3D reconstruction of the abdomen allows the plastic surgeons to better visualize the patient’s anatomy and has definite clinical utility.     

A combination of three-dimensional printing and computer-assisted virtual surgical procedure for preoperative planning of acetabular fracture reduction

ObjectiveTreatment of acetabular fractures remains one of the most challenging tasks that orthopaedic surgeons face. An accurate assessment of the injuries and preoperative planning are essential for an excellent reduction. The purpose of this study was to evaluate the feasibility, accuracy and effectiveness of performing 3D printing technology and computer-assisted virtual surgical procedures for preoperative planning in acetabular fractures. We hypothesised that more accurate preoperative planning using 3D printing models will reduce the operation time and significantly improve the outcome of acetabular fracture repair.MethodsTen patients with acetabular fractures were recruited prospectively and examined by CT scanning. A 3-D model of each acetabular fracture was reconstructed with MIMICS14.0 software from the DICOM file of the CT data. Bone fragments were moved and rotated to simulate fracture reduction and restore the pelvic integrity with virtual fixation. The computer-assisted 3D image of the reduced acetabula was printed for surgery simulation and plate pre-bending. The postoperative CT scan was performed to compare the consistency of the preoperative planning with the surgical implants by 3D-superimposition in MIMICS14.0, and evaluated by Matta's method.ResultsComputer-based pre-operations were precisely mimicked and consistent with the actual operations in all cases. The pre-bent fixation plates had an anatomical shape specifically fit to the individual pelvis without further bending or adjustment at the time of surgery and fracture reductions were significantly improved. Seven out of 10 patients had a displacement of fracture reduction of less than 1 mm; 3 cases had a displacement of fracture reduction between 1 and 2 mm.ConclusionsThe 3D printing technology combined with virtual surgery for acetabular fractures is feasible, accurate, and effective leading to improved patient-specific preoperative planning and outcome of real surgery. The results provide useful technical tips in planning pelvic surgeries.     

Quantification and visualization of three-dimensional inconsistency of the ventrointermediate nucleus of the thalamus in the Schaltenbrand-Wahren brain atlas

Summary   Background. This work quantifies and visualises 3D inconsistencies of the ventrointermediate nucleus (VIM) of the thalamus, including the VIM externum (VIMe) and VIM internum (VIMi), in the Schaltenbrand-Wahren (SW) brain atlas. Method. For each VIM, VIMe, VIMi the 3D models, 3D-A, 3D-C and 3D-S were reconstructed from the SW axial, coronal and sagittal microseries, respectively, by applying a shape-based method. All 3D models, placed in the SW coordinate system, were compared quantitatively in terms of location (centroids), size (volumes), shape (normalised eigen values), orientation (eigen vectors), and mutual spatial relationships (overlaps and inclusions). Findings. The reconstructed 3D models differ significantly in location, size, shape, and inclusion rate. The centroid of 3D-A/VIM differs considerably from those of 3D-C/VIM and 3D-S/VIM. The difference between the centroids of 3D-C/VIM and 3D-S/VIM is in laterality only: that of 3D-C/VIM is located more medially (11.85 mm) than that of 3D-S/VIM (14.62 mm). 3D-A/VIM has the smallest volume (69.00 mm³); 3D-C/VIM is 3.71 and 3D-S/VIM 3.89 times larger. The overlap is also highly variable: 104.88 mm³ for 3D-C/VIM with 3D-S/VIM, and very low (3.22 and 7.45 mm³) when 3D-A/VIM is involved. The highest inclusion rate is for 3D-C/VIM with 3D-S/VIM (39.10 and 40.97%) and the lowest for 3D-A/VIM with 3D-C/VIM (1.26 and 4.66%). The centroid of 3D-A/VIMe differs noticeably from those of 3D-C/VIMe and 3D-S/VIMe. The difference between the centroids of 3D-C/VIMe and 3D-S/VIMe is mainly in laterality: that of 3D-C/VIMe is located more medially (12.91 mm) than that of 3D-S/VIMe (16.65 mm). 3D-A/VIMe has the smallest volume (49.87 mm³); 3D-S/VIMe is 3.24 and 3D-C/VIMe 3.36 times larger. The overlap sizes are low: 32.72 mm³ for 3D-C/VIMe with 3D-S/VIMe, and very low (1.32 and 2.01 mm³) when 3D-A/VIMe is involved. The inclusion rates are also low: the highest is for 3D-C/VIMe with 3D-S/VIMe (19.53 and 20.29%) and the lowest for 3D-A/VIMe with 3D-C/VIMe (1.19 and 4.01%). Lateral scaling of the coronal microseries by 1.2897 to match the 3D-C/VIMe and 3D-S/VIMe centroids increases the inclusion rates for the sagittal microseries by more than twice. The volume of scaled 3D-C enlarges to 216.24 mm³ which is 1.34 bigger than that of 3D-S. There are substantial differences among the centroids of 3D-A/VIMi, 3D-C/VIMi and 3D-S/VIMi. The centroid of 3D-A/VIMi is located more anteriorly (−1.92 mm) than that of 3D-C/VIMi (−5.02 mm). The centroid of 3D-A/VIMi is located more ventrally (2.88 mm) than those of 3D-C/VIMi and 3D-S/VIMi (each at 5.34 mm). 3D-A/VIMi has the smallest volume (19.75 mm³); 3D-S/VIMi is 3.23 and 3D-C/VIMi 4.30 times larger. 3D-A/VIMi practically does not overlap with 3D-C/VIMi and 3D-S/VIMi. The inclusion rates for 3D-C/VIMi with 3D-S/VIMi are medium (32.63 and 43.43%). Conclusion. Each VIM, VIMe, VIMi as reconstructed from the SW atlas has a significant 3D inaccuracy within each orientation and across them. Therefore, absolute and direct reliance on the original SW atlas is unreliable and unsafe, and this atlas has to be used with great care and understanding of its strengths and limitations. Correspondence: Wieslaw L. Nowinski, DSc, PhD, Biomedical Imaging Lab, Agency for Science Technology and Research, 30 Biopolis Street, #07-01 Matrix, 138671 Singapore.     

Structural Parameters of the Proximal Femur by 3-Dimensional Dual-Energy X-ray Absorptiometry Software: Comparison With Quantitative Computed Tomography

Structural parameters of the proximal femur evaluate the strength of the bone and its susceptibility to fracture. These parameters are computed from dual-energy X-ray absorptiometry (DXA) or from quantitative computed tomography (QCT). The 3-dimensional (3D)-DXA software solution provides 3D models of the proximal femur shape and bone density from anteroposterior DXA scans. In this paper, we present and evaluate a new approach to compute structural parameters using 3D-DXA software. A cohort of 60 study subjects (60.9?±?14.7?yr) with DXA and QCT examinations was collected. 3D femoral models obtained by QCT and 3D-DXA software were aligned using rigid registration techniques for comparison purposes. Geometric, cross-sectional, and volumetric structural parameters were computed at the narrow neck, intertrochanteric, and lower shaft regions for both QCT and 3D-DXA models. The accuracy of 3D-DXA structural parameters was evaluated in comparison with QCT. Correlation coefficients (r) between geometric parameters computed by QCT and 3D-DXA software were 0.86 for the femoral neck axis length and 0.71 for the femoral neck shaft angle. Correlation coefficients ranged from 0.86 to 0.96 for the cross-sectional parameters and from 0.84 to 0.97 for the volumetric structural parameters. Our study demonstrated that accurate estimates of structural parameters for the femur can be obtained from 3D-DXA models. This provides clinicians with 3D indexes related to the femoral strength from routine anteroposterior DXA scans, which could potentially improve osteoporosis management and fracture prevention.     

Planning of anatomical liver segmentectomy and subsegmentectomy with 3-dimensional simulation software

Background

The aim of this study was to evaluate whether 3-dimensional (3D) simulation software is applicable to and useful for anatomic liver segmentectomy and subsegmentectomy.

Methods

A prospective study of 83 consecutive patients who underwent anatomic segmentectomy or subsegmentectomy using the puncture method was performed. All patients underwent 3D simulation analysis (SA) preoperatively for planning operative procedures. The clinical information acquired by 3D SA and the consistency of virtual and real hepatectomy were evaluated.

Results

The time needed for completing 3D SA was 18.3 ± .7 minutes. Three-dimensional SA proposed resection of multiple segments or subsegments in 29 patients (35%). It also helped complement the resection line in 26 patients (31%) who lacked a bold staining area on the liver surface. The volume of segment or subsegment calculated by 3D SA was correlated with the actual resected specimen (R² = .9942, P < .01). The bordering hepatic veins were clearly exposed in 71 patients (86%), in accordance with completed drawings by 3D SA.

Conclusions

Three-dimensional SA showed accurate completed drawings and assisted liver surgeons in planning and executing anatomic segmentectomy and subsegmentectomy.