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

Preoperative Simulation and Three-Dimensional Model for the Operative Treatment of Tibiofibular Diaphyseal Fracture: A Randomized Controlled Clinical Trial

BACKGROUND

In order to ascertain the safety and therapeutic efficacy of preoperative simulation in conjunction with three-dimensional (3D) printing modalities for the surgical management of tibiofibular diaphyseal fractures. We postulate that preoperative simulation and three-dimensional (3D) printing techniques have a significant impact on reducing the mean operative time, diminishing intraoperative blood loss, and decreasing the frequency of fluoroscopic.

MATERIAL AND METHODS

Sixty patients with tibiofibular diaphyseal fracture were divided into the conventional surgery group (n = 30) and the 3D printing group (n = 30). In the 3D printing group, preoperative equal-ratio fracture models prepared using the 3D printing technique were used to perform preoperative simulation, guide the real surgical operation, examine implant reduction and placement as well as preoperative plate/screw size. The operation time, intraoperative bleeding, frequency of fluoroscopies, Visual Analog Scale (VAS), and Johner-Wruhs Scale were recorded.

RESULTS

The operation time, blood loss, and the frequency of fluoroscopy during operation in the group with preoperative simulation and 3D printing were less than that in the conventional surgery group (p < 0.001). Meanwhile, the Visual Analog Scale (VAS) and Johner-Wruhs Scale were also improved in both groups.

CONCLUSION

The findings indicated that preoperative simulation and three-dimensional (3D) printing may facilitate the treatment of tibiofibular diaphyseal fractures, potentially enhancing preoperative planning and contributing to the precision and personalization of the surgical procedure. Thus, the application of this technology possesses considerable promise for future utilization in clinical practice.

TRIAL REGISTRY

Name of the registry: This study was registered in the Chinese Clinical Trial Registry; Trial registration number: ChiCTR2100052379.

Digital Technology-Assisted "Z" Osteotomy lower limb corrective procedures

Background and study aims

Digital technology is a transformative product of the information age. z-osteotomy is a surgical procedure that corrects limb angulation and lengthens shortening deformities within a 40 mm difference in limb length.The purpose of this study is to Introduce the surgical technique of digitally assisted "Z" osteotomy for correction of angular and length deformities of the lower limbs and investigating its clinical efficacy.

Patients and methods

A retrospective study was conducted on five patients with multiplanar angular deformities of the lower extremity combined with limb shortening(n=5). The objective of the study was to assess the effectiveness of computer-assisted preoperative design planning and 3D-printed surgical guide fabrication in guiding precise orthopedic procedures. The study compared various parameters, including femoral or tibial cross-sections, coronal and sagittal deformities, limb length, modified Barthel Index, and post-operative complications.

Results

Five patients were granted 17.20±6.83 months of follow-up after surgery, with adequate correction of lower limb deformity, significant improvement in postoperative self-care ability improved Barthel index 90±3.08 points (P<0.05). One patient experienced postoperative wound pain at 3 months, which subsequently diminished significantly by the 4-month follow-up assessment., four cases had no complications.

Conclusions

The new surgical method of digital technology-assisted "Z" osteotomy for correction of complex deformities of the lower limbs has remarkable clinical results, can accurately correct multi-planar angular deformities and realize limb lengthening at the same time, being safe and reliable.

The Role of 3D Custom Implants in Upper Extremity Surgery

SUMMARY

As the technology of three-dimensional (3D) printing becomes more refined and accessible, multiple applications of its use are becoming more commonplace in upper extremity surgery. 3D-printed models have been beneficial in preoperative planning of complex cases of acute trauma or malunions, contributing to spatial understanding or even contouring of implants. Custom guides can also be created to assist intraoperatively with precise placement of osteotomies or arthroplasty implants. Finally, custom 3D implants have been described for cases of bone loss in the upper extremity. This can be for relatively small gaps after malunion correction or extensive defects, typically for trauma or tumor. Articular defects can also be addressed with this technology, although special considerations should be given to the implant design and longevity in these situations. Because of the relatively recent nature of 3D implants, long-term data are lacking. However, they show great promise in an expanding range of challenging clinical indications.

Three-dimensional printed models can reduce costs and surgical time for complex proximal humeral fractures: preoperative planning, patient satisfaction, and improved resident skills

BACKGROUND

Proximal humeral fractures (PHFs) are still controversial with regards to treatment and are difficult to classify. The study's objective is to show that preoperative planning performed while handling a three-dimensional (3D) printed anatomical model of the fracture can ensure a better understanding of trauma for both surgeons and patients.

MATERIALS AND METHODS

Twenty patients (group A, cases) with complex PHF were evaluated preoperatively by reproducing life-size, full-touch 3D anatomical models. Intraoperative blood loss, radiographic controls, duration of surgery, and clinical outcomes of patients in group A were compared with 20 patients (group B, controls) who underwent standard preoperative evaluation. Additionally, senior surgeons and residents, as well as group A patients, answered a questionnaire to evaluate innovative preoperative planning and patient compliance. Cost analysis was evaluated.

RESULTS

Intraoperative radiography controls and length of operation were significantly shorter in group A. There were no differences in clinical outcomes or blood loss. Patients claim a better understanding of the trauma suffered and the proposed treatment. Surgeons assert that the planning of the definitive operation with 3D models has had a good impact. The development of this tool has been well received by the residents. The surgery was reduced in length by 15%, resulting in savings of about EUR 400 for each intervention.

CONCLUSIONS

Fewer intraoperative radiography checks, shorter surgeries, and better patient compliance reduce radiation exposure for patients and healthcare staff, enhance surgical outcomes while reducing expenses, and lower the risk of medicolegal claims.

LEVEL OF EVIDENCE

Level I, prospective randomized case-control study.

Virtual registration of comminuted bone fracture and preoperative assessment of reconstructed bone model using the Procrustes algorithm based on CT dataset

A research work was undergone in a virtual bone reduction process for reconstruction of the comminuted pelvic bone fracture using a CT scan dataset of patients. This includes segmentation, 3D model optimization and bone registration technique. The accuracy of the reconstructed bone model was validated using Finite Element Method. Analysed and applied various segmentation techniques to segregate the injured bone structure. The ICP (Iterative Closest Point), Procrustes algorithm and Canny edge detection algorithm were applied to understand the bone registration process for surgery in detail. The average RMS error, mean absolute distance, mean absolute deviation, and mean signed distance of the reconstructed bone model using proposed algorithms involving 10 patient datasets in a group were found to be 1.77, 1.48, 1.51 and -0.31 mm respectively. The calculated RMS error value proved minimal error in semi-automatic registration than other existing automatic registration techniques. Therefore, the proposed approach is suitable for virtual bone reduction for comminuted pelvic bone fracture. This method could also be implemented for various other bone fracture reconstruction requirements.

Cinematic rendering improves the AO/OTA classification of distal femur fractures compared to volume rendering: a retrospective single-center study

Purpose: Correctly classifying distal femur fractures is essential for surgical treatment planning and patient prognosis. This study assesses the potential of Cinematic Rendering (CR) in classifying these fractures, emphasizing its reported ability to produce more realistic images than Volume Rendering (VR). Methods: Data from 88 consecutive patients with distal femoral fractures collected between July 2013 and July 2020 were included. Two orthopedic surgeons independently evaluated the fractures using CR and VR. The inter-rater and intra-rater agreement was evaluated by using the Cicchetti-Allison weighted Kappa method. Accuracy, precision, recall, and F1 score were also calculated. Diagnostic confidence scores (DCSs) for both imaging methods were compared using chi-square or Fisher's exact tests. Results: CR reconstruction yielded excellent inter-observer (Kappa = 0.989) and intra-observer (Kappa = 0.992) agreement, outperforming VR (Kappa = 0.941 and 0.905, respectively). While metrics like accuracy, precision, recall, and F1 scores were higher for CR, the difference was not statistically significant (p > 0.05). However, DCAs significantly favored CR (p < 0.05). Conclusion: CR offers a superior visualization of distal femur fractures than VR. It enhances fracture classification accuracy and bolsters diagnostic confidence. The high inter- and intra-observer agreement underscores its reliability, suggesting its potential clinical importance.

Virtual Surgical Planning and Patient-Specific Instruments for Correcting Lower Limb Deformities in Pediatric Patients: Preliminary Results from the In-Office 3D Printing Point of Care

(1) Background: Virtual reality and 3D printing are transforming orthopedic surgery by enabling personalized three-dimensional (3D) models for surgical planning and Patient-Specific Instruments (PSIs). Hospitals are establishing in-house 3D printing centers to reduce costs and improve patient care. Pediatric orthopedic surgery also benefits from these technologies, enhancing the precision and personalization of treatments. This study presents preliminary results of an In-Office 3D Printing Point of Care (PoC), outlining considerations and challenges in using this program for treating lower limb deformities in pediatric patients through Virtual Surgical Planning (VSP) and 3D-printed Patient-Specific Instruments (PSIs). (2) Materials and Methods: Pediatric patients with congenital or acquired lower limb deformities undergoing surgical correction based on VSP, incorporating 3D-printed PSIs when required, were included in this study. The entire process of VSP and 3D printing at the In-Office PoC was illustrated. Data about deformity characteristics, surgical procedures, and outcomes, including the accuracy of angular correction, surgical times, and complications, were reported. (3) Results: In total, 39 bone correction procedures in 29 patients with a mean age of 11.6 ± 4.7 years (range 3.1-18.5 years) were performed according to VSP. Among them, 23 procedures were accomplished with PSIs. Surgeries with PSIs were 45 min shorter, with fewer fluoroscopy shots. Optimal correction was achieved in 37% of procedures, while the remaining cases showed under-corrections (41%) or over-corrections (22%). Major complications were observed in four patients (13.8%). (4) Conclusions: The In-Office 3D Printing Point of Care is becoming an essential tool for planning and executing complex corrections of lower limb deformities, but additional research is needed for optimizing the prediction and accuracy of the achieved corrections.

Simulation Software to Plan the Treatment of Acetabular Fractures: The Patient-Specific Biomechanical Model

OBJECTIVES

The objective of this study was to assess the impact of using simulation software for preoperative planning: a patient-specific biomechanical model (PSBM) in acetabular surgery. The secondary objectives were to assess operating time, intraoperative bleeding, and peroperative complications.

DESIGN

This is a prospective control study.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Between January 2019 and December 2022, patients with operative acetabular fracture treated by the first author were prospectively enrolled.

INTERVENTION

Patients were divided into 2 groups according to the use or not of PSBM for preoperative planning. When PSBM was used, data were extracted from the preoperative high-resolution computed tomography scans to build a biomechanical model implemented in a custom software [simulation (SIM group)]. When computed tomography scans were not performed in our hospital, PSBM was not feasible (non-SIM group).

MAIN OUTCOME MEASUREMENTS

Radiological results, surgery duration, blood loss, and peroperative complications were recorded.

RESULTS

Sixty-six patients were included; 26 in the PSBM group and 40 in the standard group. The 2 groups were comparable regarding fracture patterns and epidemiological data. After simulation, in the SIM group, a poor reduction (>3 mm) was found in 2 of 26 patients (7.7%) versus 11 of 40 patients (27.5%) in the non-SIM group, P = 0.048. The mean operative time was shorter after simulation (110 minutes vs. 155 minutes, P = 0.01), and the mean blood loss was reduced (420 vs. 670 mL, P = 0.01).

CONCLUSIONS

By reducing the peroperative trials for reduction, PSBM allows better reduction in a shorter operative time and with less blood loss.

LEVEL OF EVIDENCE

Level II: prospective study.

Preoperative Virtual Reduction Planning Algorithm of Fractured Pelvis Based on Adaptive Templates

OBJECTIVE

The minimally invasive treatment of pelvic fractures is one of the most challenging trauma orthopedics surgeries, where preoperative planning is crucial for the performance and outcome of the surgery. However, planning the ideal position of fragments currently relies heavily on the experience of the surgeon.

METHODS

A pelvic fracture virtual reduction algorithm for target position is provided based on statistical shape models (SSM). First, according to sexual dimorphism, pelvic SSM based on point cloud curvature down-sampling are constructed as adaptive templates. Then, an optimization algorithm is designed to iteratively adjust the target pose of the fragments and the adaptive matching of the templates. Finally, the feasibility of the method is verified by simulating fractures and clinical data.

RESULTS

The pelvis has complex shape characteristics, which can be analyzed by SSM to clearly understand the pattern of change. Experiments showed that the SSM-based pelvic fracture reduction method had translation and rotation errors of 2.20±1.09 mm and 3.16±1.26° in simulated cases, and 2.78±0.95 mm and 3.10±0.53° in clinical cases, which has higher accuracy than methods based on mean shape models, and wider applicability than methods based on pelvic symmetry.

CONCLUSION

The pelvic digital model created by SSM has good generalization properties, and the SSM-based virtual reduction algorithm can effectively reconstruct the target position of the fractured pelvis in preoperative planning.

SIGNIFICANCE

The proposed reduction method has the characteristics of high precision and wide application range, which provides a powerful tool for the surgeon's virtual preoperative planning.

Three-Dimensional Printed Plate Template Versus Hemipelvis Model in Patient-Specific Plate Preparation for Posterior Wall Acetabular Fractures

OBJECTIVE

The application of three-dimensional (3D) printing technology in the management of posterior wall acetabular fractures can greatly reduce surgical invasiveness and operative time and simplify the procedure of reconstruction plate contouring, but the cost and time of patient-specific plate preparation on the basis of traditional 3D-printed pelvis model should not be neglected. We described a new method for patient-specific plate preparation by using 3D-printed plate template. The study aimed to assess the effectiveness and feasibility of the 3D-printed plate template in patient-specific plate preparation for posterior wall acetabular fractures.

METHODS

A total of 65 cases of posterior wall acetabular fractures with surgical treatment from December 2012 to December 2020 were chosen. According to the different plate contouring methods, the 65 cases were divided into three groups, which were group A (21 cases), group B (20 cases), and group C (24 cases). In group A, the 3D-printed plate template was used to contour the patient-specific reconstruction plate before surgery, whereas the 3D-printed hemipelvis model was adopted for group B. In group C, the reconstruction plate was contoured intraoperatively. Among the three groups, the instrumentation time, surgical time, blood loss, patient-specific plate preparation time, complications, reduction quality, and hip function were compared. The Kruskal-Wallis test was used to analyze the reduction quality and hip function among three groups.

RESULTS

In comparison with group C, patients in groups A and B were featured by obviously shorter instrumentation time (-22, -23 min), shorter surgical time (-46, -44 min), and less intraoperative blood loss (-110, -122 mL). Compared to the hemipelvis model in group B (2.29 ± 0.56 vs. 12.70 ± 3.79 days), the 3D printing time for plate templates in group A was significantly shorter. The reduction quality and hip function had no obvious statistical difference among the three groups. The complication rate within group A (3/21) and group B (3/20) were both slightly lower than group C (5/24), with no obvious difference.

CONCLUSIONS

Both the patient-specific pre-contoured plate fixation methods based on the 3D-printed hemipelvis model and plate template can achieve satisfactory clinical efficacy, with the advantage of shorter instrumentation and surgical time, and less intraoperative blood loss. However, 3D printing of plate template is easier and less time-consuming, considering the shorter time and less cost for 3D printing of physical model.

Acetabular fractures from Judet and Letournel to the present: Research trends and global outcomes with bibliometric analysis during 1980 to 2022

Fractures of the acetabulum are one of the most challenging injuries treated by orthopedic surgeons. However, a bibliometric analysis has not been performed in the literature on acetabular fractures, which seriously affect the quality of life of patients. The aim of this study was to summarize the bibliometric and intellectual structure, and determine and map the most recent trends on the topic of acetabular fractures by analyzing the social and structural relationships between the different research components of articles published on the acetabular fractures. 1599 articles on acetabular fractures published between 1980 and 2022 were extracted from the Web of Science (WoS) database and analyzed. Bibliometric visualization maps were used to reveal trending topics, citation analyses, and international collaborations. Spearman correlation analysis was performed for correlation investigations. The trend in the expected number of articles to be published over the next few years was displayed using the exponential smoothing estimator. The top 3 contributing countries to the literature were United States of America (USA) (551, 34.4%), China (170, 10.6%), and Germany (160, 10%). The most active author was Berton R. Moed (n = 29) and the most active institution was the University of California System (n = 41). A high-level statistically significant correlation was found between the number of articles on the topic of acetabular fractures published by nations and the gross domestic product (GDP) and GDP per capita values of those countries (R = 0.719, P < .001; R = 0.701, P < .001, respectively). The trending topics researched in recent years were 3D printing, 3-dimensional printing, outcomes, Open Reduction and Internal Fixation (ORIF), mortality, Kocher-Langenbeck, Pararectus approach, tranexamic acid, transfusion, epidemiology, fracture mapping, modified Stoppa approach, post-traumatic osteoarthritis, pelvis fracture, pelvic trauma, fracture reduction, and pelvic ring injury. The leading countries in research on the subject of acetabular fractures were seen to be western countries with large economies (especially the USA, European countries, and Canada) and China, India and Turkey.

3-D Printed Fracture Models Improve Resident Performance and Clinical Outcomes in Operative Fracture Management

OBJECTIVE

To determine if preoperative examination of patient additive manufactured (AM) fracture models can be used to improve resident operative competency and patient outcomes.

DESIGN

Prospective cohort study. Seventeen matched pairs of fracture fixation surgeries (for a total of 34 surgeries) were performed. Residents first performed a set of baseline surgeries (n = 17) without AM fracture models. The residents then performed a second set of surgeries randomly assigned to include an AM model (n = 11) or to omit it (n = 6). Following each surgery, the attending surgeon evaluated the resident using an Ottawa Surgical Competency Operating Room Evaluation (O-Score). The authors also recorded clinical outcomes including operative time, blood loss, fluoroscopy duration, and patient reported outcome measurement information system (PROMIS) scores of pain and function at 6 months.

SETTING

Single-center academic level one trauma center.

PARTICIPANTS

Twelve orthopaedic residents, between postgraduate year (PGY) 2 and 5, participated in this study.

RESULTS

Residents significantly improved their O-Scores between the first and second surgery when they trained with AM models for the second surgery (p = 0.004, 2.43 ± 0.79 versus 3.73 ± 0.64). Similar improvements were not observed in the control group (p = 0.916, 2.69 ± 0.69 versus 2.77 ± 0.36). AM model training also significantly improved clinical outcomes, including surgery time (p = 0.006), fluoroscopy exposure time (p = 0.002), and patient reported functional outcomes (p = 0.0006).

CONCLUSIONS

Conclusions: Training with AM fracture models improves the performance of orthopaedic surgery residents during fracture surgery.

Structural analysis of customized 3D printed plate for pelvic bone by comparison with conventional plate based on bending process

Pelvic bone fracture is highly complex, and its anatomical reduction is difficult. Therefore, patient-specific customized plates have been developed using three-dimensional (3D) printing technology and are being increasingly used. In this study, the reduction status in five representative pelvic fracture models was compared between two groups: the 3D printing plate (3DP) group using a patient-specific 3D printed plate after virtual reduction and the conventional plate (CP) group using a conventional plate by manual bending. The 3DP and CP groups included 10 and 5 cases, respectively. The fractured models were reduced virtually and their non-locking metal plates were customized using 3D printing. The process of contouring the conventional plates to fit the contact surface of the bone with the bending tool was conducted by an experienced pelvic bone trauma surgeon. The reduction and fixation achieved using the two different plate groups was compared, and the significance of differences in the results was analyzed using paired t-tests, after verifying the normality of data distribution. The vertex distances between the surface of the bone and the contact surface of the plate were significantly lower in the 3DP group than in the CP group (0.407 ± 0.342 and 2.195 ± 1.643, respectively, P = 0.008). Length and angular variations, which are measurements of the reduction state, were also lower in the 3DP group than in the CP group (length variation: 3.211 ± 2.497 and 5.493 ± 3.609, respectively, P = 0.051; angular variation: 2.958 ± 1.977 and 4.352 ± 1.947, respectively, P = 0.037). The customized 3D printed plate in the virtual reduction model provided a highly accurate reduction of pelvic bone fractures, suggesting that the customized 3D printed plate may help ensure easy and accurate reduction.

Three-dimensional computed tomography mapping techniques in the morphometric analysis of AO/OTA 33A and 33C distal femoral fractures: a retrospective single-center study

Purpose: Complex distal femoral fractures involve a challenging set of considerations that must be known to provide optimal management. This study aimed to determine the location and frequency of fracture lines and comminution zones in AO/OTA types 33A and 33C distal femoral fractures using three-dimensional computed tomography mapping. Methods: Seventy-four consecutive eligible patients were included. Fracture fragments for each patient were reconstructed, virtually reduced, and adjusted to match the distal femoral template. Then, all fracture lines and comminuted areas were extracted in transparent mode, and corresponding heat maps were constructed. Finally, these maps, along with the quantitative analysis findings of the counts and volumes of each fragment, were used to summarize the characteristics of the fractures. Results: Thirty-four females and 40 males [average age, 58 years (range, 18-92 years)] presented with a distal femoral fracture. There were 53 AO/OTA type 33A fractures, and 21 AO/OTA type 33C fractures. These two patterns differed significantly on fracture fragment count, comminuted zone fracture fragment count, and mean comminuted zone fracture fragment volume (p < 0.05). Most of the fracture line heat zones were in the femoral epiphysis, intercondylar notch of the femur, and patellofemoral joint. The comminuted area heat regions were mostly found on the lateral, anterior, and posterior femoral diaphysis, with less involvement on the medial side. Conclusion: Our findings may serve as a guide for the surgical approach selection of complex distal femur fractures, the placement strategy of the internal fixation, and the optimization of the osteotomy plan for biomechanical studies.

Development of a Statistical Shape Model and Assessment of Anatomical Shape Variations in the Hemipelvis

Knowledge about anatomical shape variations in the pelvis is mandatory for selection, fitting, positioning, and fixation in pelvic surgery. The current knowledge on pelvic shape variation mostly relies on point-to-point measurements on 2D X-ray images and computed tomography (CT) slices. Three-dimensional region-specific assessments of pelvic morphology are scarce. Our aim was to develop a statistical shape model of the hemipelvis to assess anatomical shape variations in the hemipelvis. CT scans of 200 patients (100 male and 100 female) were used to obtain segmentations. An iterative closest point algorithm was performed to register these 3D segmentations, so a principal component analysis (PCA) could be performed, and a statistical shape model (SSM) of the hemipelvis was developed. The first 15 principal components (PCs) described 90% of the total shape variation, and the reconstruction ability of this SSM resulted in a root mean square error of 1.58 (95% CI: 1.53-1.63) mm. In summary, an SSM of the hemipelvis was developed, which describes the shape variations in a Caucasian population and is able to reconstruct an aberrant hemipelvis. Principal component analyses demonstrated that, in a general population, anatomical shape variations were mostly related to differences in the size of the pelvis (e.g., PC1 describes 68% of the total shape variation, which is attributed to size). Differences between the male and female pelvis were most pronounced in the iliac wing and pubic rami regions. These regions are often subject to injuries. Future clinical applications of our newly developed SSM may be relevant for SSM-based semi-automatic virtual reconstruction of a fractured hemipelvis as part of preoperative planning. Lastly, for companies, using our SSM might be interesting in order to assess which sizes of pelvic implants should be produced to provide proper-fitting implants for most of the population.

Significantly reducing the presurgical preparation time for anterior pelvic fracture surgery by faster creating patient-specific curved plates

BACKGROUND

To shorten the preoperative preparation time, reconstruction plates were designed using the computed tomography (CT)-based three-dimensional (3D) medical imaging surgical planning software OOOPDS. In addition, 3D printing was used to generate curved plates for anterior pelvic fracture surgeries.

METHODS

This study analyzed two groups with the same 21 patients who underwent surgery for traumatic anterior pelvic ring fractures. In Group 1, the direct reconstruction plates were preoperatively contoured according to the anatomical 3D-printed pelvic model. In Group 2, the fixation plates were contoured according to the 3D printed plate templates, which were created based on the simulated plate templates by the OOOPDS software. The processing time, including the 3D printing time for the pelvic models in Group 1, the 3D printing time for the fixation plate templates in Group 2, and the pre-contouring time for the plates in both groups, was recorded.

RESULTS

The mean time of pre-contouring for the curved reconstruction plates in Group 2 was significantly less than in Group 1 (-55 min; P < 0.01). The mean time of 3D printing for the 3D plate template model in Group 2 was significantly less than that for the 3D pelvic model in Group 1 (-869 min; P < 0.01). Experimental results showed that the printing time for the plate pre-contouring and the 3D plate templates could be effectively reduced by approximately 93% and 90%, respectively.

CONCLUSION

This method can shorten the preoperative preparation time significantly.

A Symmetry-Based Superposition Method for Planning and Surgical Outcome Assessment

Computer-aided surgical planning has been widely used to increase the safety and predictability of surgery. The validation of the target of surgical planning to surgical outcomes on a patient-specific model is an important issue. The aim of this research was to develop a robust superposition method to assess the deviation of planning and outcome by using the symmetrical characteristic of the affected target. The optimal symmetry plane (OSP) of an object is usually used to evaluate the degree of symmetry of an object. We proposed a refined OSP-based contouring method to transfer a complex three-dimensional superposition operation into two dimensions. We compared the typical iterative closest point (ICP) algorithm with the refined OSP-based contouring method and examined the differences between them. The results using the OSP-based method were much better than the traditional method. As for processing time, the OSP-based contouring method was 11 times faster than the ICP method overall. The proposed method was not affected by the metallic artifacts from medical imaging or geometric changes due to surgical intervention. This technique can be applied for post-operative assessment, such as quantifying the differences between surgical targets and outcomes as well as performing long-term medical follow-up.

The application of additive manufacturing technology in pelvic surgery: A bibliometrics analysis

With the development of material science, additive manufacturing technology has been employed for pelvic surgery, addressing the challenges, such as the complex structure of the pelvis, difficulty in exposing the operative area, and poor visibility, of the traditional pelvic surgery. However, only limited studies have been done to review the research hotspots and trends of the additive manufacturing technology applied for pelvic surgery. In this study, we comprehensively analyzed the literatures related to additive manufacturing technology in pelvic surgery by a bibliometrics analysis and found that additive manufacturing technology is widely used in several aspects of preoperative diagnosis, preoperative planning, intraoperative navigation, and personalized implants for pelvic surgery. Firstly, we searched and screened 856 publications from the Web of Science Core Collection (WoSCC) with TS = (3D printing OR 3D printed OR three-dimensional printing OR additive manufacturing OR rapid prototyping) AND TS = (pelvis OR sacrum OR ilium OR pubis OR ischium OR ischia OR acetabulum OR hip) as the search strategy. Then, 565 of these were eliminated by evaluating the titles and abstracts, leaving 291 pieces of research literature whose relevant information was visually displayed using VOSviewer. Furthermore, 10 publications with high citations were selected by reading all publications extensively for carefully evaluating their Titles, Purposes, Results, Limitations, Journal of affiliation, and Citations. Our results of bibliometric analysis demonstrated that additive manufacturing technology is increasingly applied in pelvic surgery, providing readers with a valuable reference for fully comprehending the research hotspots and trends in the application of additive manufacturing technology in pelvic surgery.

Computer-assisted preoperative planning of bone fracture fixation surgery: A state-of-the-art review

Background: Bone fracture fixation surgery is one of the most commonly performed surgical procedures in the orthopedic field. However, fracture healing complications occur frequently, and the choice of the most optimal surgical approach often remains challenging. In the last years, computational tools have been developed with the aim to assist preoperative planning procedures of bone fracture fixation surgery. Objectives: The aims of this review are 1) to provide a comprehensive overview of the state-of-the-art in computer-assisted preoperative planning of bone fracture fixation surgery, 2) to assess the clinical feasibility of the existing virtual planning approaches, and 3) to assess their clinical efficacy in terms of clinical outcomes as compared to conventional planning methods. Methods: A literature search was performed in the MEDLINE-PubMed, Ovid-EMBASE, Ovid-EMCARE, Web of Science, and Cochrane libraries to identify articles reporting on the clinical use of computer-assisted preoperative planning of bone fracture fixation. Results: 79 articles were included to provide an overview of the state-of-the art in virtual planning. While patient-specific geometrical model construction, virtual bone fracture reduction, and virtual fixation planning are routinely applied in virtual planning, biomechanical analysis is rarely included in the planning framework. 21 of the included studies were used to assess the feasibility and efficacy of computer-assisted planning methods. The reported total mean planning duration ranged from 22 to 258 min in different studies. Computer-assisted planning resulted in reduced operation time (Standardized Mean Difference (SMD): -2.19; 95% Confidence Interval (CI): -2.87, -1.50), less blood loss (SMD: -1.99; 95% CI: -2.75, -1.24), decreased frequency of fluoroscopy (SMD: -2.18; 95% CI: -2.74, -1.61), shortened fracture healing times (SMD: -0.51; 95% CI: -0.97, -0.05) and less postoperative complications (Risk Ratio (RR): 0.64, 95% CI: 0.46, 0.90). No significant differences were found in hospitalization duration. Some studies reported improvements in reduction quality and functional outcomes but these results were not pooled for meta-analysis, since the reported outcome measures were too heterogeneous. Conclusion: Current computer-assisted planning approaches are feasible to be used in clinical practice and have been shown to improve clinical outcomes. Including biomechanical analysis into the framework has the potential to further improve clinical outcome.

One-stop computerized virtual planning system for the surgical management of posterior wall acetabular fractures

Background

Posterior wall acetabular fractures remain one of the most difficult fracture injuries to treat. Accurate assessment of fracture characteristics and appropriate preoperative surgical strategies are essential for excellent reduction. This paper evaluates the feasibility and effectiveness of a one-stop computerized virtual planning system for the surgical management of posterior wall acetabular fractures.

Methods

52 cases of posterior wall acetabular fractures treated surgically were selected in our department between January 2015 and December 2020 for retrospective analysis. 52 cases were classified into group A (25 patients) and group B (27 patients) according to whether computerized virtual planning procedures were performed preoperatively. In group A, virtual surgical simulation was conducted using a one-stop computerized planning system preoperatively. In group B, traditional surgery was employed. Reduction quality, surgical time, blood loss, hip function, complications, and instrumentation time were compared between the two groups.

Results

The actual surgery for all patients in group A was essentially the same as the virtual surgery before the operation. Compared to group B, patients in group A had markedly shorter surgical time (−43 min), shorter instrumentation time (−20 min), and less intraoperative blood loss (−130 ml). However, no significant statistical difference was observed in reduction quality and hip function. The complication rate was slightly lower in group A (4/25) than in group B (7/27), without a significant difference.

Conclusion

The one-stop computerized virtual planning system is a highly effective, user-friendly and educational tool for allowing the cost-efficient surgical simulation of posterior wall acetabular fractures and providing a more individualized therapeutic schedule. The one-stop computerized planning system is feasible to treat posterior wall acetabular fractures, which is an effective method than the conventional treatment of posterior wall acetabular fractures.

Trial registration: retrospective registration.

Feasibility of Computer-Aided Design in Limb Lengthening Surgery: Surgical Simulation and Guide Plates

Objective

To evaluate the feasibility and utility of computer‐aided design (CAD) in surgical treatment of leg length discrepancy (LLD) using monorail external fixators.

Methods

In the present case series, we retrospectively analyzed seven patients diagnosed with LLD who were surgically treated using a monorail external fixator between June 2018 and August 2020. A personalized surgical emulation of each patient was designed using CAD based on preoperative CT scans to measure limb parameters. Through reverse engineering, a surgical guide plate was then designed to assist with correcting the limb deformity. Patient general information and clinical history, leg length, mechanical lateral distal femoral angle (mLDFA), anatomical anterior distal tibial angle (aADTA), and surgical parameters were recorded during the perioperative period. Three months after external fixator removal, distraction‐consolidation time (DCT), healing index (HI), and lower extremity function score (LEFS) were calculated, and statistically analyzed by paired T‐test.

Results

The mean limb lengthening achieved was 6.41 ± 2.54 (range, 3.30–10.54) cm with either varus or valgus correction. The mean operative duration was 151 ± 41.87 (84–217) minutes and mean blood loss was 53.58 ± 22.51(25–87) ml. The mean distraction‐consolidation time was 3.67 ± 1.13 (range, 2.5–6.0) months and mean external fixator duration was 11 ± 2.45 (range, 8–14) months. The mean healing index (HI) was 18.11 ± 3.58 (range, 12.8–22.7) days/cm. Mean LEFS scores improved postoperatively from 32.17 ± 8.57 (range, 24–45) to 61.17 ± 6.68 (range, 50–67) with a significant difference (T = –14.26,P < 0.001).

Conclusions

Simultaneous length and angular correction can be achieved by incorporating CAD into the surgical treatment of patients with LLD, without compromising postoperative lower limb function. CAD demonstrates utility in the surgical treatment of LLD by improving the functionality of monorail external fixators.

Utility of 3D printed models as adjunct in acetabular fracture teaching for Orthopaedic trainees

OBJECTIVE

To evaluate the use of 3-D printed models as compared to didactic lectures in the teaching of acetabular fractures for Orthopaedic trainees.

METHODS

This was a randomised prospective study conducted in a tertiary hospital setting which consisted of 16 Orthopaedic residents. Ten different cases of acetabular fracture patterns were identified and printed as 3-D models. The baseline knowledge of orthopaedic residents regarding acetabular fracture classification and surgical approach was determined by an x-ray based pre-test. Trainees were then randomly assigned into two groups. Group I received only lectures. Group II were additionally provided with 3-D printed models during the lecture. Participants were then assessed for comprehension and retention of teaching.

RESULTS

Sixteen trainees participated in the trial. Both Group 1 and 2 improved post teaching with a mean score of 2.5 and 1.9 to 4.4 and 6 out of 10 respectively. The post test score for fracture classification and surgical approach were significantly higher for 3-D model group (p < 0.05). Trainees felt that the physical characteristics of the 3-D models were a good representation of acetabular fracture configuration, and should be used routinely for teaching and surgical planning.

CONCLUSION

3-D printed model of real clinical cases have significant educational impact compared to lecture-based learning towards improving young trainees' understanding of complex acetabular fractures.

The Comparison of Clinical Efficacy of Minimally Invasive Tarsal Sinus Approach and L-Type Incision Approach Combined with 3D Printing Technology in Calcaneal Fracture

Purpose

To explore the comparison of the reduction of the subtalar articular surface and other postoperative effects of the minimally invasive tarsal sinus approach and lateral L-shaped incision conventional approach for the treatment of calcaneal fracture with 3D printing technology.

Methods

Patients who received surgical treatment for calcaneal fractures in the First Affiliated Hospital of Henan University of Science and Technology from June 2019 to December 2020 were collected. 3D printing equipment produced the affected side reduction heel bone fracture model and navigation template model. The tarsal sinus approach was used in the experimental group, and the lateral L-shaped incision approach was used in the control group. Patients were followed up 3 days, 1 month, 3 months, 6 months, and 12 months after the operation. Imaging indicators were measured 12 months after surgery, and scores from American Foot and Ankle Orthopaedic Society (AOFAS) and MSF were performed.

Results

Operation time was 70.52 ± 13.16 in the control group and 55.24 ± 12.25 minutes in the experimental group (P < 0.001). Intraoperative blood loss was 98.77 ± 18.65 in the control group and 89.56 + 17.54 in the experimental group (P > 0.05). The duration of antibiotic use was 5.53 ± 3.24 days in the control group and 5.48 ± 4.18 days in the experimental group (P > 0.05). The frequency of fluoroscopy was 6.56 ± 1.72 in the control group and 3.88 ± 1.05 in the experimental group (P < 0.001). Fracture healing time was 3.24 ± 0.52 months in the control group and 3.08 ± 0.58 months in the experimental group (P > 0.05). The postoperative Böhler angle was 28.31 ± 3.14 in the control group and 29.24 ± 2.76 in the experimental group (P > 0.05). Postoperative subtalar articular displacement (step > 2 mm) was observed in 4 patients in the control group and 1 in the experimental group (P < 0.05). MSF score was 90.12 ± 4.85 in the control group and 91.36 ± 2.58 in the experimental group (P > 0.05).

Conclusion

The study found that the experimental group was significantly better than the control group in terms of the operation time, intraoperative fluoroscopy times, and success rate of reduction of the subtalar articular surface. 3D printing technology can shorten the operation time, accurately reduce the fracture block, and reduce the secondary trauma, which is conducive to the functional recovery of the affected foot.

Generation of hemipelvis surface geometry based on statistical shape modelling and contralateral mirroring

Personalised fracture plates manufactured using 3D printing offer an improved treatment option for unstable pelvic ring fractures that may not be adequately secured using off-the-shelf components. To design fracture plates that secure the bone fragments in their pre-fracture positions, the fractures must be reduced virtually using medical imaging-based reconstructions, a time-consuming process involving segmentation and repositioning of fragments until surface congruency is achieved. This study compared statistical shape models (SSMs) and contralateral mirroring as automated methods to reconstruct the hemipelvis using varying amounts of bone surface geometry. The training set for the geometries was obtained from pelvis CT scans of 33 females. The root-mean-squared error (RMSE) was quantified across the entire surface of the hemipelvis and within specific regions, and deviations of pelvic landmarks were computed from their positions in the intact hemipelvis. The reconstruction of the entire hemipelvis surfaced based on contralateral mirroring had an RMSE of 1.21 ± 0.29 mm, whereas for SSMs based on the entire hemipelvis surface, the RMSE was 1.11 ± 0.29 mm, a difference that was not significant (p = 0.32). Moreover, all hemipelvis reconstructions based on the full or partial bone geometries had RMSEs and landmark deviations from contralateral mirroring that were significantly lower (p < 0.05) or statistically equivalent to the SSMs. These results indicate that contralateral mirroring tends to be more accurate than SSMs for reconstructing unilateral pelvic fractures. SSMs may still be a viable method for hemipelvis fracture reconstruction in situations where contralateral geometries are not available, such as bilateral pelvic factures, or for highly asymmetric pelvic anatomies.

Fast-Track-Protocol for Optimization of Presurgical Planning in Acute Surgical Treatment of Acetabular Quadrilateral Plate Fractures Using 3D Printing Technology and Pre-Contoured Reconstruction Plates

Background. Preoperative planning and 3D printing can be used to treat pelvic bone fractures using pre-contoured surgical plates, in particular complex, comminuted fractures involving the acetabulum and quadrilateral plate. The aim of the study was to develop a Fast-Track-Protocol (fast track methodology) for creating 3D anatomical models, that could be used to shape surgical plates, using open-source software and budget 3D printers. Such a ‘low-budget’ approach would allow a hospital-based multidisciplinary team to carry out pre-surgical planning and treat complex pelvic fractures using 3D technology. Methods. The study included 5 patients with comminuted pelvic fractures. For each patient, CT (computed tomography) data were converted into two 3D models of the pelvis-injured side and mirrored model of the contralateral, uninjured hemipelvis. These models were 3D printed and used as templates to shape surgical plates. Results. A Fast-Track-Protocol was established and used to successfully treat 5 patients with complex, comminuted fractures of the pelvis. Conclusion. Using the Fast-Track-Protocol it was possible to prepare 3D printed models and patient-specific pre-contoured plates within 2 days of hospital admittance. Such an approach resulted in better surgical technique and shorter operative times, while incurring relatively low costs.

Application of computerized virtual preoperative planning procedures in comminuted posterior wall acetabular fractures surgery

Background

The treatment of comminuted posterior wall acetabular fractures remains challenging due to the difficulty in understanding of fracture patterns and lack of appropriate preoperative planning process. Virtual preoperative planning procedures are now being commonly used in orthopedic surgery to aid in management of such complex problems. Our aim was to evaluate the feasibility and clinical value of a new method by applying computerized virtual preoperative planning procedures in the treatment of comminuted posterior wall acetabular fractures.

Methods

A total of 45 patients with comminuted posterior wall acetabular fractures from June 2014 to December 2018 were retrospectively analyzed. Based on the usage of computerized virtual preoperative planning procedures, they were assigned to group A and group B. In group A (24 patients), the new method was applied before surgery. In group B (21 patients), the conventional surgery was performed without assistance of computerized virtual preoperative planning procedures. The two groups were assessed in terms of blood loss, surgical time, reduction quality, fracture healing time, postoperative complications, and hip function.

Results

There were no significant differences in demographic data between the two groups. Patients in group A had significantly less intraoperative blood loss (429.58 vs 570.24 ml, P < 0.001) and shorter operation time (154.79 vs 181.90 min, P < 0.01) compared to group B. Using the Matta scoring system, the reduction was graded as anatomic in 20 cases, imperfect in three cases and poor in one case in group A, versus 16 cases was graded as anatomic, three as imperfect and two as poor for group B. According to the modified Merle d’Aubigné score, hip function was graded as excellent in 15 cases, good in seven cases, fair in one and poor in one for group A in comparison to 11 cases, seven cases, two cases, and one case for group B, respectively. The reduction quality and hip function did not differ within the two groups (P > 0.05). The general postoperative complication rate in group A and group B was 12.5% and 28.6%, respectively, but the difference between the two groups was not statistically significant.

Conclusion

The application of computerized virtual preoperative planning procedures is feasible in comminuted posterior wall acetabular fractures. It helps orthopedic surgeons better understand the fracture characteristics, enables simulation of the reduction process and preoperative planning of internal fixation methods. This new preoperative planning method using a 3D virtual model is a more effective method than conventional method in surgical treatment of comminuted posterior wall acetabular fractures.

Trial registration retrospectively registered.

Preoperative Simulation and Three-Dimensional Model for the Operative Treatment of Forearm Double Fracture: A Randomized Controlled Clinical Trial

BACKGROUND

To assess the safety and efficacy of preoperative simulation and three-dimensional (3D) models in the treatment of ulnoradial diaphyses fracture. It was hypothesized that preoperative simulation and 3D printing might significantly shorten the mean operative time, intraoperative bleeding, and intraoperative fluoroscopy.

MATERIAL AND METHODS

Forty patients with forearm double fracture were divided into 3D printing group and conventional surgery group. Preoperative simulation and 3D printing were performed on patients in the 3D printing group to examine implant reduction and placement as well as preoperative plate/screw size. The operation time, intraoperative bleeding, and frequency of fluoroscopies were recorded.

RESULTS

In the conventional surgery group, the operative time, intraoperative bleeding, and the frequency of fluoroscopy were 106.2 ± 15.92 min, 61.45 ± 11.33 ml and 5.65 ± 1.23 times, whereas in the 3D printing group, values of all the three parameters were better than those of the conventional surgery group (91.3 ± 14.85 min, 48.6 ± 10.39 ml and 3.85 ± 1.04 times, respectively). The forearm pronation and supination of the 3D printing group improved to 79.55 ± 5.12° and 76.80 ± 3.96°, respectively. In the conventional surgery group, patients also had significant improvement in these indicators, which improved to 78.60 ± 5.18° and 75.4 ± 5.30°.

CONCLUSIONS

The results showed that preoperative simulation and 3D printing can enhance the safety as well as personalization of the surgical process during the treatment of forearm double fracture and therefore holds potential for future application in clinical practice.

TRIAL REGISTRY

Name of the registry: This study was registered in the Chinese Clinical Trial Registry; Trial registration number: ChiCTR2100045790.

A Bibliometric Analysis of the Field of Computer-Assisted Orthopedic Surgery during 2002–2021

Background

This study aimed to investigate the characteristics of research articles and research trends in computer-assisted orthopedic surgery (CAOS) by conducting bibliometric analyses.

Methods

CAOS-related research articles published in international journals from 2002 to 2021 were collected using the PubMed database and analyzed using the bibliometric method. Their publication year, journal name, corresponding author's country name, and the number of citations of all collected articles were noted. Contents of the articles were analyzed to evaluate the time point and anatomical site at which the digital technique was applied. Further, the 20-year period was divided into two halves of 10 years each to analyze the research trends.

Results

A total of 639 CAOS-related articles were identified. An average of 32.0 CAOS-related articles were published annually, with an average of 20.6 and 43.3 published in the first half and second half, respectively. Of all articles, 47.6% were published in the top 10 journals, and 81.2% were written in the top 10 countries. The total numbers of citations were 11.7 and 6.3 in the first and second halves, respectively, but the average annual number of citations was higher in the second half than in the first one. Articles on application of digital techniques during surgery were 62.3% and those on pre-surgery application were 36.9%. Further, articles in the knee (39.0%), spine (28.5%), and hip and pelvis (21.5%) fields accounted for 89.0% of the total publications. But the increase in publications in the said period was highest in the fields of the hand and wrist (+1,300.0%), ankle (+466.7%), and shoulder (+366.7%).

Conclusions

Over the last 20 years, the publication of CAOS-related research articles in international journals has grown steadily. Although the knee, spine, hip, and pelvis fields account for most CAOS-related research, research in new fields is also increasing. This study analyzed the types of articles and trends in CAOS-related research and provided useful information for future research in the field of CAOS.

3D printing in orthopaedic surgery: a scoping review of randomized controlled trials

AIMS

The use of 3D printing has become increasingly popular and has been widely used in orthopaedic surgery. There has been a trend towards an increasing number of publications in this field, but existing literature incorporates limited high-quality studies, and there is a lack of reports on outcomes. The aim of this study was to perform a scoping review with Level I evidence on the application and effectiveness of 3D printing.

METHODS

A literature search was performed in PubMed, Embase, and Web of Science databases. The keywords used for the search criteria were ((3d print*) OR (rapid prototyp*) OR (additive manufactur*)) AND (orthopaedic). The inclusion criteria were: 1) use of 3D printing in orthopaedics, 2) randomized controlled trials, and 3) studies with participants/patients. Risk of bias was assessed with Cochrane Collaboration Tool and PEDro Score. Pooled analysis was performed.

RESULTS

Overall, 21 studies were included in our study with a pooled total of 932 participants. Pooled analysis showed that operating time (p < 0.001), blood loss (p < 0.001), fluoroscopy times (p < 0.001), bone union time (p < 0.001), pain (p = 0.040), accuracy (p < 0.001), and functional scores (p < 0.001) were significantly improved with 3D printing compared to the control group. There were no significant differences in complications.

CONCLUSION

3D printing is a rapidly developing field in orthopaedics. Our findings show that 3D printing is advantageous in terms of operating time, blood loss, fluoroscopy times, bone union time, pain, accuracy, and function. The use of 3D printing did not increase the risk of complications. Cite this article: Bone Joint Res 2021;10(12):807-819.

Heat Sterilization Effects on Polymeric, FDM-Optimized Orthopedic Cutting Guide for Surgical Procedures

Improvements in software for image analysis have enabled advances in both medical and engineering industries, including the use of medical analysis tools to recreate internal parts of the human body accurately. A research analysis found that FDM-sourced elements have shown viability for a customized and reliable approach in the orthopedics field. Three-dimensional printing has allowed enhanced accuracy of preoperative planning, leading to reduced surgery times, fewer unnecessary tissue perforations, and fewer healing complications. Furthermore, using custom tools chosen for each procedure has shown the best results. Bone correction-related surgeries require customized cutting guides for a greater outcome. This study aims to assess the biopolymer-based tools for surgical operations and their ability to sustain a regular heat-sterilization cycle without compromising the geometry and fit characteristics for a proper procedure. To achieve this, a DICOM and FDM methodology is proposed for fast prototyping of the cutting guide by means of 3D engineering. A sterilization test was performed on HTPLA, PLA, and nylon polymers. As a result, the unique characteristics within the regular autoclave sterilization process allowed regular supplied PLA to show there were no significant deformations, whilst annealed HTPLA proved this material’s capability of sustaining repeated heat cycles due to its crystallization properties. Both of these proved that the sterilization procedures do not compromise the reliability of the part, nor the safety of the procedure. Therefore, prototypes made with a similar process as this proposal could be safely used in actual surgery practices, while nylon performed poorly because of its hygroscopic properties.

Computer-assisted preoperative planning of reduction of and osteosynthesis of scapular fracture: A case report

Introduction

Reports on the use of computer-assisted trauma surgery of comminuted scapula fracture are still quite rare. In this article, we present a case of comminuted scapula fracture, the surgical reconstruction of which was pre-operatively planned using a complex software solution.

Materials and methods

For surgical planning of the fracture, we used the TraumaTech software facilitating virtual reconstruction (both manual and automatic), surgery planning, design of the implant, planning of screw placement and lengths, and production of a 3D print model of the fracture and the implant. The software also supported ordering such custom-made plate from a plate producer who was capable of fast and precise production of the plate.

Results

The surgery using the custom-ordered plate was successful. The actual used screw lengths did not differ from the planned ones by more than 2 mm. One year after the surgery, the patient was capable of more demanding activities and doing sports activities.

Conclusion

This approach provides a great way to prevent complications of the surgery and to shorten its duration. To the best of our knowledge, this is the first description of the treatment of a scapula comminuted fracture utilizing computer-assisted preoperative planning.

Does 3D-Assisted Acetabular Fracture Surgery Improve Surgical Outcome and Physical Functioning?-A Systematic Review

Three-dimensional technology is increasingly being used in acetabular fracture treatment. No systematic reviews are available about the added clinical value of 3D-assisted acetabular fracture surgery compared to conventional surgery. Therefore, this study aimed to investigate whether 3D-assisted acetabular fracture surgery compared to conventional surgery improves surgical outcomes in terms of operation time, intraoperative blood loss, intraoperative fluoroscopy usage, complications, and postoperative fracture reduction, and whether it improves physical functioning. Pubmed and Embase databases were searched for articles on 3D technologies in acetabular fracture surgery, published between 2010 and February 2021. The McMaster critical review form was used to assess the methodological quality. Differences between 3D-assisted and conventional surgery were evaluated using the weighted mean and odds ratios. Nineteen studies were included. Three-dimensional-assisted surgery resulted in significantly shorter operation times (162.5 ± 79.0 versus 296.4 ± 56.0 min), less blood loss (697.9 ± 235.7 mL versus 1097.2 ± 415.5 mL), and less fluoroscopy usage (9.3 ± 5.9 versus 22.5 ± 20.4 times). The odds ratios of complications and fracture reduction were 0.5 and 0.4 for functional outcome in favour of 3D-assisted surgery, respectively. Three-dimensional-assisted surgery reduces operation time, intraoperative blood loss, fluoroscopy usage, and complications. Evidence for the improvement of fracture reduction and functional outcomes is limited.

3D printed composite model of pelvic osteochondroma and nerve roots

BACKGROUND

3D-printing has become increasingly utilized in the preoperative planning of clinical orthopaedics. Surgical treatment of bone tumours within the pelvis is challenging due to the complex 3D bone structure geometry, as well as the proximity of vital structures. We present a unique case where a composite bone and nerve model of the lower lumbar spine, pelvis and accompanying nerve roots was created using 3D-printing. The 3D-printed model created an accurate reconstruction of the pelvic tumour and traversing nerves for preoperative planning and allowed for efficient and safe surgery.

CASE PRESENTATION

We present a unique case where a composite bone and nerve model of the lower lumbar spine, pelvis and accompanying nerve roots was created using 3D-printing. The bony pelvis and spine model was created using the CT, whereas the nerve roots were derived from the MRI and printed in an elastic material. 3D-printed model created an accurate reconstruction of the pelvic tumour and traversing nerves for preoperative planning and allowed for efficient and safe surgery. Pelvic tumour surgery is inherently dangerous due to the delicate nature of the surrounding anatomy. The composite model enabled the surgeon to very carefully navigate the anatomy with a focused resection and extreme care knowing the exact proximity of the L3 and L4 nerve roots.

CONCLUSION

The patient had complete resection of this tumour, no neurological complication and full resolution of his symptoms due to careful, preoperative planning with the use of the composite 3D model.

Fracture planning is easy: Development of a basic method of digital planning based on the traditional pencil and paper technique

INTRODUCTION

Preoperative planning constitutes a fundamental tool in the management of fractures; however, its practical application is far from the desired, perhaps due to the absence of a basic and simple method, adapted to the current times. We describe a digital planning method, halfway between the traditional and the technological, which preserves its educational essence, allows the understanding of the fracture and the individualization of the osteosynthesis.

MATERIAL AND METHODS

After the initial analysis of the fracture and the patient's characteristics, different measurements are made on X-ray and CT images with a digital medical imaging software. These images are then copied into a presentation program (Microsoft® PowerPoint or Keynote ©Apple Inc.), in which the main fragments and fracture lines are traced with the computer pointer. These are subsequently moved into a reduced position and the implants for internal fixation are graphically represented together with a guide of the surgical strategy.

RESULTS

We show 4 cases of different types of fractures operated through reduction and osteosynthesis after preoperative planning according to the described method. The basic points for the surgical planning, logistics, tactics and postoperative radiological results of each case are detailed.

CONCLUSIONS

Despite rise of advanced planning software, traditional paper and pencil methods are still fundamental, even more so for the trauma surgeon in training. The digital planning method described is very appropriate for this purpose, as it combines the advantages of both methods: simplicity, accessibility, quickness, low-cost, reproducibility, educational character, efficiency and possibility of simulation, corrections and reuse of cases.

Accuracy of Patient-Specific Drilling Guides in Acetabular Fracture Surgery: A Human Cadaver Study

Due to the complex anatomical shape of the pelvis, screw placement can be challenging in acetabular fracture surgery. This study aims to assess the accuracy of screw placement using patient-specific surgical drilling guides applied to pre-contoured conventional implants in acetabular fracture surgery. CT scans were made of four human cadavers to create 3D models of each (unfractured) pelvis. Implants were pre-contoured on 3D printed pelvic models and optically scanned. Following virtual preoperative planning, surgical drilling guides were designed to fit on top of the implant and were 3D printed. The differences between the pre-planned and actual screw directions (degrees) and screw entry points (mm) were assessed from the pre- and postoperative CT-scans. The median difference between the planned and actual screw direction was 5.9° (IQR: 4–8°) for the in-plate screws and 7.6° (IQR: 6–10°) for the infra-acetabular and column screws. The median entry point differences were 3.6 (IQR: 2–5) mm for the in-plate screws and 2.6 (IQR: 2–3) mm for the infra-acetabular and column screws. No screws penetrated into the hip joint or caused soft tissue injuries. Three-dimensional preoperative planning in combination with surgical guides that envelope pre-contoured conventional implants result in accurate screw placement during acetabular fracture surgery.

3D-Printing of Drug-Eluting Implants: An Overview of the Current Developments Described in the Literature

The usage of 3D-printing for drug-eluting implants combines the advantages of a targeted local drug therapy over longer periods of time at the precise location of the disease with a manufacturing technique that easily allows modifications of the implant shape to comply with the individual needs of each patient. Research until now has been focused on several aspects of this topic such as 3D-printing with different materials or printing techniques to achieve implants with different shapes, mechanical properties or release profiles. This review is intended to provide an overview of the developments currently described in the literature. The topic is very multifaceted and several of the investigated aspects are not related to just one type of application. Consequently, this overview deals with the topic of 3D-printed drug-eluting implants in the application fields of stents and catheters, gynecological devices, devices for bone treatment and surgical screws, antitumoral devices and surgical meshes, as well as other devices with either simple or complex geometry. Overall, the current findings highlight the great potential of the manufacturing of drug-eluting implants via 3D-printing technology for advanced individualized medicine despite remaining challenges such as the regulatory approval of individualized implants.

In-House, Fast FDM Prototyping of a Custom Cutting Guide for a Lower-Risk Pediatric Femoral Osteotomy

Three-dimensional printed custom cutting guides (CCGs) are becoming more and more investigated in medical literature, as a patient-specific approach is often desired and very much needed in today’s surgical practice. Three-dimensional printing applications and computer-aided surgical simulations (CASS) allow for meticulous preoperatory planning and substantial reductions of operating time and risk of human error. However, several limitations seem to slow the large-scale adoption of 3D printed CCGs. CAD designing and 3D printing skills are inevitably needed to develop workflow and address the study; therefore, hospitals are pushed to include third-party collaboration, from highly specialized medical centers to industrial engineering companies, thus increasing the time and cost of labor. The aim of this study was to move towards the feasibility of an in-house, low-cost CCG 3D printing methodology for pediatric orthopedic (PO) surgery. The prototype of a femoral cutting guide was developed for its application at the IOR—Rizzoli Orthopedic Institute of Bologna. The element was printed with an entry-level 3D printer with a high-temperature PLA fiber, whose thermomechanical properties can withstand common steam heat sterilization without bending or losing the original geometry. This methodology allowed for extensive preoperatory planning that would likewise reduce the overall surgery time, whilst reducing the risks related to the intervention.

Virtual implantation technique to estimate endoprosthetic contact of percutaneous osseointegrated devices in the tibia

Percutaneous osseointegrated (OI) devices have an endoprosthesis attached to the residual bone of an amputated limb, then pass permanently through the skin to be connected to the distal prosthetic componentry outside of the body. Whether the bone-anchoring region of current OI endoprostheses are cylindrical, and/or conical, they require intimate bone-endoprosthesis contact to promote stabilizing bone attachment. However, removing too much cortical bone to achieve more contact leads to thinner and, subsequently, weaker cortical walls. Endoprostheses need to be designed to balance these factors, namely maximizing the contact, while minimizing the volume of bone removed. In this study, 27 human tibias were used to develop and validate a virtual implantation method. Then, 40 additional tibias were virtually implanted with mock cylindrical and conical bone-anchoring regions at seven residual limb lengths to measure resultant bone-endoprosthesis contact and bone removal. The ratio of bone-endoprosthesis contact to bone volume removed showed the conical geometry had more contact area per volume bone removed for all amputation levels (p ≤ 0.001). In both mock devices, cortical penetration of the endoprosthesis at 20% residual length occurred in 74% of cases evaluated, indicating that alternative endoprosthesis geometries may be needed for clinical success in that region of bone.

Utility of a 3-dimensionally printed color-coded bone model to visualize impinging osteophytes for arthroscopic débridement arthroplasty in elbow osteoarthritis

BACKGROUND

The identification and precise removal of bony impingement lesions during arthroscopic débridement arthroplasty for elbow osteoarthritis require a high level of experience and surgical skill. We have developed a new technique to identify impinging osteophytes on a computer display by simulating elbow motion using the multiple positions of 3-dimensional (3D) elbow models created from computed tomography data. Moreover, an actual color-coded 3D model indicating the impinging osteophytes was created with a 3D printer and was used as an intraoperative reference tool. This study aimed to verify the efficacy of these new technologies in arthroscopic débridement for elbow osteoarthritis.

METHODS

We retrospectively studied 16 patients treated with arthroscopic débridement for elbow osteoarthritis after a preoperative computer simulation. Patients who underwent surgery with only the preoperative simulation were assigned to group 1 (n = 8), whereas those on whom we operated using a color-coded 3D bone model created from the preoperative simulation were assigned to group 2 (n = 8). Elbow extension and flexion range of motion (ROM), the Mayo Elbow Performance Score (MEPS), and the severity of osteoarthritis were compared between the groups.

RESULTS

Although preoperative elbow flexion and MEPS values were not significantly different between the groups, preoperative extension was significantly more restricted in group 2 than in group 1 (P = .0131). Group 2 tended to include more severe cases according to the Hastings-Rettig classification (P = .0693). ROM and MEPS values were improved in all cases. No significant differences in postoperative ROM or MEPS values were observed between the groups. There were no significant differences in the improvement in ROM or MEPS values between the 2 groups.

CONCLUSIONS

The use of preoperative simulation and a color-coded bone model could help to achieve as good postoperative ROM and MEPS values for advanced elbow osteoarthritis as those for early and intermediate stages.

CaDIS: Cataract dataset for surgical RGB-image segmentation

Video feedback provides a wealth of information about surgical procedures and is the main sensory cue for surgeons. Scene understanding is crucial to computer assisted interventions (CAI) and to post-operative analysis of the surgical procedure. A fundamental building block of such capabilities is the identification and localization of surgical instruments and anatomical structures through semantic segmentation. Deep learning has advanced semantic segmentation techniques in the recent years but is inherently reliant on the availability of labelled datasets for model training. This paper introduces a dataset for semantic segmentation of cataract surgery videos complementing the publicly available CATARACTS challenge dataset. In addition, we benchmark the performance of several state-of-the-art deep learning models for semantic segmentation on the presented dataset. The dataset is publicly available at https://cataracts-semantic-segmentation2020.grand-challenge.org/.

Planning acetabular fracture reduction using a patient-specific biomechanical model: a prospective and comparative clinical study

PURPOSE

A simple, patient-specific biomechanical model (PSBM) is proposed in which the main surgical tools and actions can be simulated, which enables clinicians to evaluate different strategies for an optimal surgical planning. A prospective and comparative clinical study was performed to assess early clinical and radiological results.

METHODS

From January 2019 to July 2019, a PSBM was created for every operated acetabular fracture (simulation group). DICOM data were extracted from the pre-operative high-resolution CT scans to build a 3D model of the fracture using segmentation methods. A PSBM was implemented in a custom software allowing a biomechanical simulation of the surgery in terms of reduction sequences. From July 2019 to December 2019, every patient with an operated for acetabular fracture without PSBM was included in the standard group. Surgery duration, blood loss, radiological results and per-operative complications were recorded and compared between the two groups.

RESULTS

Twenty-two patients were included, 10 in the simulation group and 12 in the standard group. The two groups were comparable regarding age, time to surgery, fracture pattern distribution and surgical approaches. The mean operative time was significantly lower in the simulation group: 113 min ± 33 (60-180) versus 184 ± 58 (90-260), p = 0.04. The mean blood loss was significantly lower in the simulation group, p = 0.01. No statistical significant differences were found regarding radiological results (p = 0.16). No per-operative complications were recorded.

CONCLUSION

This study confirms that pre-operative planning in acetabular surgery based on a PSBM results in a shorter operative time and a reduction of blood loss during surgery. This study also confirms the feasibility of PSBM planning in daily clinical routine.

LEVEL OF EVIDENCE

II: prospective study.

Traditional three-dimensional printing technology versus three-dimensional printing mirror model technology in the treatment of isolated acetabular fractures: a retrospective analysis

OBJECTIVE

This study was performed to compare the clinical outcomes of traditional three-dimensional (3D) printing technology and 3D printing mirror model technology in the treatment of isolated acetabular fractures.

METHODS

Prospectively maintained databases were reviewed to retrospectively compare patients with an isolated acetabular fracture who were treated with traditional 3D printing technology (Group T) or 3D printing mirror model technology (Group M) from 2011 to 2017. In total, 146 advanced-age patients (146 hips) with an isolated acetabular fracture (Group T, n = 72; Group M, n = 74) were assessed for a mean follow-up period of 29 months (range, 24-34 months). The primary endpoint was the postoperative Harris hip score (HHS). The secondary endpoints were the operation time, intraoperative blood loss, fluoroscopy screening time, fracture reduction quality, and incidence of postoperative complications at the final follow-up.

RESULTS

The HHS, operation time, intraoperative blood loss, fluoroscopy screening time, and incidence of postoperative complications were significantly different between the groups, with Group M showing superior clinical outcomes.

CONCLUSION

In patients with an isolated acetabular fracture, 3D printing mirror model technology might lead to more accurate and efficient treatment than traditional 3D printing technology.

Preoperative 3D Modeling and Printing for Guiding Periacetabular Osteotomy

INTRODUCTION

Achieving adequate acetabular correction in multiple planes is essential to the success of periacetabular osteotomy (PAO). Three-dimensional (3D) modeling and printing has the potential to improve preoperative planning by accurately guiding intraoperative correction. The authors therefore asked the following questions: (1) For a patient undergoing a PAO, does use of 3D modeling with intraoperative 3D-printed models create a reproducible surgical plan to obtain predetermined parameters of correction including lateral center edge angle (LCEA), anterior center edge angle (ACEA), Tonnis angle, and femoral head extrusion index (FHEI)? and (2) Can 3D computer modeling accurately predict when a normalized FHEI can be achieved without the need for a concomitant femoral-sided osteotomy?

METHODS

A retrospective review was conducted on 42 consecutive patients that underwent a PAO. 3D modeling software was utilized to simulate a PAO in order to achieve normal LCEA, ACEA, Tonnis angle, and FHEI. If adequate FHEI was not achieved, a femoral osteotomy was simulated. 3D models were printed as intraoperative guides. Preoperative, simulated and postoperative radiographic ACEA, LCEA, Tonnis angle, and FHEI were measured and compared statistically.

RESULTS

A total of 40 patients had a traditional PAO, and 2 had an anteverting-PAO. The simulated LCEA, ACEA, Tonnis angle, and FHEI were within a median difference of 3 degrees, 1 degrees, 1 degrees, and 0% of postoperative values, respectively, and showed no statistical difference. Of those that had a traditional PAO, all 34 patients were correctly predicted to need a traditional acetabular-sided correction alone and the other 6 were correctly predicted to need a concomitant femoral osteotomy for a correct prediction in 100% of patients.

CONCLUSION

This study demonstrates that for PAO surgery, 3D modeling and printing allow the surgeon to accurately create a reproducible surgical plan to obtain predetermined postoperative hip coverage parameters. This new technology has the potential to improve preoperative/intraoperative decision making for hip dysplasia and other complex disorders of the hip.

Feasibility of Imaging-Based 3-Dimensional Models to Design Patient-Specific Osteosynthesis Plates and Drilling Guides

IMPORTANCE

In acetabular fracture surgery, achieving an optimal reconstruction of the articular surface decreases the risk of osteoarthritis and the subsequent need for total hip arthroplasty. However, no one-size-fits-all osteosynthesis plate is available owing to differences in fracture patterns and variations in pelvic anatomy. Currently, osteosynthesis plates need to be manually contoured intraoperatively, often resulting in inadequate reduction and fixation of the fractured segments.

OBJECTIVE

To determine the feasibility and accuracy of a novel concept of fast-track 3-dimensional (3-D) virtual surgical planning and patient-specific osteosynthesis for complex acetabular fracture surgery.

DESIGN, SETTING, AND PARTICIPANTS

This case series study examines the use of patient-specific osteosynthesis plates for patients needing operative treatment for displaced associated-type acetabular fractures at a tertiary university-affiliated referral center and level 1 trauma center between January 1, 2017, and December 31, 2018. Models were created in 3-D based on computed tomography (CT) data, fractures were virtually reduced, and implant positions were discussed in a multidisciplinary team of clinicians and engineers. Patient-specific osteosynthesis plates with drilling guides were designed, produced, sterilized and clinically applied within 4 days. Data were analyzed at the 1-year follow-up.

EXPOSURES

Development and clinical implementation of personalized fracture surgery.

MAIN OUTCOMES AND MEASURES

The primary outcome was the quality of the reduction as determined by the postoperative CT scan. The secondary outcomes were accuracy of the screw placement and clinical outcome using patient-reported outcome measures.

RESULTS

Ten patients with a median (range) age of 63 (46-79) years with an acetabular fracture were included. The median (interquartile range [IQR]) preoperative gap was 20 (15-22) mm, and the median (IQR) step-off was 5 (3-11) mm. Postoperatively, the median (IQR) gap was reduced to 3 (2-5) mm (P = .005), and the median (IQR) step-off was reduced to 0 (0-2) mm (P = .01), indicating good fracture reduction, indicating good fracture reduction. The mean difference between the preoperative and postoperative gap was 14.6 (95% CI, 10-19) mm, and the mean difference in step-off was 5.7 (95% CI, 2-9) mm. The median (IQR) difference in screw direction between the planning and actual surgery was only 7.1° (7°-8°). All patients retained their native hip and reported good physical functioning at follow-up.

CONCLUSIONS AND RELEVANCE

These findings suggest that 3-D virtual surgical planning, manufacturing, and clinical application of patient-specific osteosynthesis plates and drilling guides was feasible and yielded good clinical outcomes. Fast-track personalized surgical treatment could open a new era for the treatment of complex injuries.

The effect of new preoperative preparation method compared to conventional method in complex acetabular fractures: minimum 2-year follow-up

OBJECTIVE

This study aimed to compare the efficacy and safety of the new method including 3D printing-based preoperative planning, surgical workshop, and contouring of the plate versus conventional method in the surgical treatment of complex acetabular fractures.

METHODS

We retrospectively analyzed the data in a cohort of 88 patients of complex acetabular fracture with mean 29.95 ± 4.84 months (24-41 months) follow-up. Patients were divided into two groups. Group 1 consisting of 41 patients were performed previewed surgery with a 3D printing-based pre-contoured plate on a 3D printing model. Group 2, comprised of 47 patients, were treated by the traditional contoured plate technique. The quality of reduction was assessed using criteria described by Matta. Functional outcome was evaluated using Modified Postel Merle D'Aubigne score. A custom-made quiz was used to evaluate the chief assistant.

RESULTS

The study showed no significant differences in measured preoperative variables except for the age between the Group 1 and Group 2 (p > 0.05). Compared with the Group 2, the intraoperative blood loss, operative time was significantly decreased in Group 1 (p < 0.05). There were no significant statistical differences in the quality of reduction and Modified Postel Merle D'Aubigne score (p > 0.05). The result of evaluation of assistant in Group 1 was significantly high than in Group 2 (p < 0.05).

CONCLUSION

3D printing-based pre-contoured plate is a more effective and reliable method than traditional contoured plate technique for treating the complex acetabular fractures. Meanwhile, the 3D printing is a useful orthopedic surgical education tool which can improve the understanding of the complex acetabular fracture for a young surgeon.

Quantitative analysis of regional specific pelvic symmetry

Understanding bilateral pelvic symmetry can be useful for analyzing complex pelvis anatomy and simplifying difficult procedures for pelvic fractures. This paper aims to quantify the degree of regional pelvic symmetry using computer-based methods. CT scans of 30 intact pelvises were digitized into 3D models and regions were defined: the ilium, acetabulum, pubis, and ischium. The right hemipelvis was aligned with the left, and deviations between the two models were quantified using method 1 (global registration) and method 2 (local registration). Symmetry was evaluated using the root mean square (RMS) of the deviations and the percentage of points within preset thresholds of ± 2 mm and ± 1 mm. The results showed that > 86% of points are within the ± 2 mm deviation threshold and average RMS are < 1.33 mm. For all regions, method 2 showed lower deviations than method 1. The pubis and ischium regions showed a large difference in symmetry between the two methods indicating high local symmetry, but a degree of global asymmetry. Conversely, the acetabular and iliac regions showed similar levels of symmetry with the two methods. When evaluated locally, the pelvic regions can be considered highly symmetric; the acetabulum is highly symmetric globally as well. These findings can be used in future studies to assess the feasibility of patient-specific implants using the mirrored contralateral hemipelvis as a template for unilateral pelvic fracture fixation. The left image shows the "cut planes" used to define four pelvic regions: the ilium, acetabulum, pubis, and ischium. The right image shows a deviation color map (DCM) used to quantify bilateral pelvic symmetry. The scale and color illustrate the degree of deviation of the left hemipelvis with the right hemipelvis with the units in millimeters (mm).

Surgical treatment for both-column acetabular fractures using pre-operative virtual simulation and three-dimensional printing techniques

Background:

Surgical treatment of both-column acetabular fractures is challenging because of the complex acetabular fracture patterns and the curved surface of the acetabulum. Seldom study has compared the application of three-dimensional (3D) printing technology and traditional methods of contouring plates intra-operatively for the surgical treatment of both-column acetabular fractures. We presented the use of both 3D printing technology and a virtual simulation in pre-operative planning for both-column acetabular fractures. We hypothesized that 3D printing technology will assist orthopedic surgeons in shortening the surgical time and improving the clinical outcomes.

Methods:

Forty patients with both-column acetabular fractures were recruited in the randomized prospective case–control study from September 2013 to September 2017 for this prospective study (No. ChiCTR1900028230). We allocated the patients to two groups using block randomization (3D printing group, n = 20; conventional method group, n = 20). For the 3D printing group, 1:1 scaled pelvic models were created using 3D printing, and the plates were pre-contoured according to the pelvic models. The plates for the conventional method group were contoured during the operation without 3D printed pelvic models. The operation time, instrumentation time, time of intra-operative fluoroscopy, blood loss, number of times the approach was performed, blood transfusion, post-operative fracture reduction quality, hip joint function, and complications were recorded and compared between the two groups.

Results:

The operation and instrumentation times in the 3D printing group were significantly shorter (130.8 ± 29.2 min, t = −7.5, P < 0.001 and 32.1 ± 9.5 min, t = −6.5, P < 0.001, respectively) than those in the conventional method group. The amount of blood loss and blood transfusion in the 3D printing group were significantly lower (500 [400, 800] mL, Mann-Whitney U = 74.5, P < 0.001 and 0 [0,400] mL, Mann-Whitney U = 59.5, P < 0.001, respectively) than those in the conventional method group. The number of the approach performed in the 3D printing group was significantly smaller than that in the conventional method group (pararectus + Kocher-Langenbeck [K-L] approach rate: 35% vs. 85%; χ² = 10.4, P < 0.05). The time of intra-operative fluoroscopy in the 3D printing group was significantly shorter than that in the conventional method group (4.2 ± 1.8 vs. 7.7 ± 2.6 s; t = −5.0, P < 0.001). The post-operative fracture reduction quality in the 3D printing group was significantly better than that in the conventional method group (good reduction rate: 80% vs. 30%; χ² = 10.1, P < 0.05). The hip joint function (based on the Harris score 1 year after the operation) in the 3D printing group was significantly better than that in the conventional method group (excellent/good rate: 75% vs. 30%; χ² = 8.1, P < 0.05). The complication was similar in both groups (5.0% vs. 25%; χ² = 3.1, P = 0.182).

Conclusions:

The use of a pre-operative virtual simulation and 3D printing technology is a more effective method for treating both-column acetabular fractures. This method can shorten the operation and instrumentation times, reduce blood loss, blood transfusion and the time of intra-operative fluoroscopy, and improve the post-operative fracture reduction quality.

Clinical trail registration:

No.ChiCTR1900028230; http://www.chictr.org.cn

Patch-based classification of gallbladder wall vascularity from laparoscopic images using deep learning

PURPOSE

In this study, we propose a deep learning approach for assessment of gallbladder (GB) wall vascularity from images of laparoscopic cholecystectomy (LC). Difficulty in the visualization of GB wall vessels may be the result of fatty infiltration or increased thickening of the GB wall, potentially as a result of cholecystitis or other diseases.

METHODS

The dataset included 800 patches and 181 region outlines of the GB wall extracted from 53 operations of the Cholec80 video collection. The GB regions and patches were annotated by two expert surgeons using two labeling schemes: 3 classes (low, medium and high vascularity) and 2 classes (low vs. high). Two convolutional neural network (CNN) architectures were investigated. Preprocessing (vessel enhancement) and post-processing (late fusion of CNN output) techniques were applied.

RESULTS

The best model yielded accuracy 94.48% and 83.77% for patch classification into 2 and 3 classes, respectively. For the GB wall regions, the best model yielded accuracy 91.16% (2 classes) and 80.66% (3 classes). The inter-observer agreement was 91.71% (2 classes) and 78.45% (3 classes). Late fusion analysis allowed the computation of spatial probability maps, which provided a visual representation of the probability for each vascularity class across the GB wall region.

CONCLUSIONS

This study is the first significant step forward to assess the vascularity of the GB wall from intraoperative images based on computer vision and deep learning techniques. The classification performance of the CNNs was comparable to the agreement of two expert surgeons. The approach may be used for various applications such as for classification of LC operations and context-aware assistance in surgical education and practice.