Preshaping plates for minimally invasive fixation of calcaneal fractures using a real-size 3D-printed model as a preoperative and intraoperative tool

Use of 3D Printing Technology in Fracture Management: A Review and Case Series

SUMMARY

Three-dimensional (3D) offers exciting opportunities in medicine, particularly in orthopaedics. The boundaries of 3D printing are continuously being re-established and have paved the way for further innovations, including 3D bioprinting, custom printing refined methods, 4D bioprinting, and 5D printing potential. The quality of these applications have been steadily improving, increasing their widespread use among clinicians. This article provides a review of the current literature with a brief introduction to the process of additive manufacturing, 3D printing, and its applications in fracture care. We illustrate this technology with a case series of 3D printing used for correction of complex fractures/nonunion. Factors limiting the use of this technology, including cost, and potential solutions are discussed. Finally, we discuss 4D bioprinting and 5D printing and their potential role in fracture surgery.

The Clinical Efficacy of Contouring Periarticular Plates on a 3D Printed Bone Model

We report our experience of preoperative plate contouring for periarticular fractures using three-dimensional printing (3DP) technology and describe its benefits. We enrolled 34 patients, including 11 with humerus midshaft fractures, 12 with tibia plateau fractures, 2 with pilon fractures, and 9 with acetabulum fractures. The entire process of plate contouring over the 3DP model was videotaped and retrospectively analyzed. The total time and number of trials for the intraoperative positioning of precontoured plates and any further intraoperative contouring events were prospectively recorded. The mismatch between the planned and postoperative plate positions was evaluated. The average plate contouring time was 9.2 min for humerus shaft, 13.8 min for tibia plateau fractures, 8.8 min for pilon fractures, and 11.6 min for acetabular fractures. Most precontoured plates (88%, 30/34) could sit on the planned position without mismatch. In addition, only one patient with humerus shaft fracture required additional intraoperative contouring. Preoperative patient specific periarticular plate contouring using a 3DP model is a simple and efficient method that may alleviate the surgical challenges involved in plate contouring and positioning.

Effectiveness in Sterilization of Objects Produced by 3D Printing with Polylactic Acid Material: Comparison Between Autoclave and Ethylene Oxide Methods

Objective  Due to the popularity of 3D technology, surgeons can create specific surgical guides and sterilize them in their institutions. The aim of the present study is to compare the efficacy of the autoclave and ethylene oxide (EO) sterilization methods for objects produced by 3D printing with polylactic acid (PLA) material. Methods Forty cubic-shaped objects were printed with PLA material. Twenty were solid and 20 were hollow (printed with little internal filling). Twenty objects (10 solid and 10 hollow) were sterilized in autoclave, forming Group 1. The others (10 solid and 10 hollow) were sterilized in EO, composing Group 2. After sterilization, they were stored and referred to culture. Hollow objects of both groups were broken during sowing, communicating the dead space with the culture medium. The results obtained were statistically analyzed (Fisher exact test and residue analysis). Results  In group 1 (autoclave), there was bacterial growth in 50% of solid objects and in 30% of hollow objects. In group 2 (EO), growth occurred in 20% of hollow objects, with no bacterial growth in solid objects (100% of negative samples). The bacteria isolated in the positive cases was non-coagulase-producing Staphylococcus Gram positive. Conclusions  Sterilization by both autoclave and EO was not effective for hollow printed objects. Solid objects sterilized by autoclave did not demonstrate 100% of negative samples and were not safe in the present assay. Complete absence of contamination occurred only with solid objects sterilized by EO, which is the combination recommended by the authors.

Development of a Pedicle Screw Fixation Simulation Model for Surgical Training Using a 3-Dimensional Printer

OBJECTIVE

Training surgeons in pedicle screw fixation (PSF) techniques during actual surgery is limited because of patient safety, complications, and surgical efficiency issues. Recent technical developments are leading the world to an era of personalized three-dimensional (3D) printing. This study aimed to evaluate the educational effect of using a 3D-printed spine model to train beginners in PSF techniques to improve screw accuracy and procedure time.

METHODS

Computed tomography (CT) scan data were used in a 3D printer to produce a life-size lumbar spine replica of L1-3 vertebrae. Four residents performed PSF thrice. Each resident performed 18 screw fixations on both sides (6 screws per trial). The time to complete the procedure and pedicle violation was recorded.

RESULTS

The average time for the 3 procedures was 42.1±2.9 minutes, 38.8±3.3 minutes, and 32.1±2.5 minutes, respectively. Furthermore, the average pedicle screw score for the 3 procedures was 13.0±0.8, 14.5±0.6, and 16.0±0.8, respectively. As the trial was repeated, the procedure time decreased and the accuracy of screw fixation tended to be more accurate.

CONCLUSIONS

It was possible to decrease the procedure time and increase accuracy through repeated training using the 3D-printed spine model. By implementing a 3Dprinted spine model based on the patient's actual CT data, surgeons can perform simulation surgery before the actual surgery. Therefore, this technology can be useful in educating residents to improve their surgical skills.

Can 3-Dimensional Printing for Calcaneal Fracture Surgery Decrease Operation Time and Improve Quality of Fracture Reduction?

We investigated whether 3-dimensional (3D) printed models can decrease operation time and improve the quality of reduction for calcaneal fractures. The study involved 48 patients with unilateral intra-articular calcaneal fractures, who were retrospectively case-matched according to Sander's classification, age, and sex. Group A (24 patients) was operated using 3D printed models as a preoperative and intraoperative tool, and group B (24 patients) was operated using standard techniques without 3D printed model. Operation time was significantly shorter for group A, compared to group B (82.3 ± 13.2 vs 91.4 ± 16.0, p = .036). The differences between the radiological parameters of operated calcaneus, compared to the normal side was similar between the 2 groups (Böhler angle, 5.3° ± 3.9° vs 4.2° ± 4.7°, p = .45, Gissane angle, 5.9° ± 12.5° vs 8.4° ± 11.0°, p = .54). The number of screws projecting more than 5 mm from the cortex was lower in group A than in group B (7/187, 4% vs 16/208, 8%, p = .11). The number of screw holes of the plate cut intraoperatively was significantly lower for group A compared to group B (1 vs 138). Although group A started weightbearing 3 to 4 weeks earlier than group B, the radiological parameters were similar between groups that early weightbearing was possible for group A using the 3D printed models (Böhler angle, - 1.5° ± 0.8° vs - 1.8° ± 1.2°, p = .28, Gissane angle, 2.5° ± 2.6° vs 3.5° ± 4.3°, p = .39). The operation time was shorter while using the 3D printed models, compared to that of the standard technique without using the 3D printed model. The radiological parameters were not statistically different, and the quality of fracture reduction seemed similar. However, with the use of 3D printed models, early weightbearing was possible without significant subsidence of reduced fragments or failure of fracture reduction, comparable to non-weightbearing cases.

Application of 3D modeling in a personalized approach to bone osteosynthesis (A literature review)

Three-dimensional printing opens up many opportunities for use in traumatology and orthopedics, because it takes into account personal characteristics of the patients. Modern methods of high-resolution medical imaging can process data to create threedimensional images for printing physical objects. Today, three-dimensional printers are able to create a model of any complexity of shape and geometry. The article provides a review of the literature about three-dimensional digital modeling in shaping implants for osteosynthesis. Data search was carried out on the Scopus, Web of Scince, Pubmed, RSCI databases for the period 2012–2022. The effectiveness of three-dimensional printing for preoperative modeling of bone plates has been confirmed: implants perfectly corresponds with the unique anatomy of the patient, since the template for it is based on the materials of computed tomography. Individual templates can be useful when the geometry of patients' bones goes beyond the standard, and when improved results of surgery are expected due to better matching of implants to the anatomical needs of patients. 

Evaluation of the effects of using 3D - patient specific models of displaced intra - articular calcaneal fractures in surgery

BACKGROUND

It was aimed to compare conventional surgery and three-dimensional (3D) model-assisted surgery used in the treatment of calcaneal fractures.

MATERIALS & METHODS

A total of 37 patients with unilateral calcaneal fractures were randomly divided into two groups as a conventional surgery group (n: 19) and a 3D model-assisted surgery group (n: 18). The preoperative, postoperative and last follow up angles of the Bohler and Gissane, calcaneal width and facet height were measured. The duration of the operation, blood loss volume, fluoroscopy usage, instrumentation time for both groups were recorded. Finally, the follow-up AOFAS scores were evaluated. A questionnaire was used to determine the perceptions of the resident doctors about the 3D model.

RESULTS

The duration of the operation, blood loss volume, fluoroscopy usage, instrumentation time for 3D model-assisted surgery group were 83.3 ± 4.6 minutes, 83.6 ± 4.6 ml, 6.8 ± 1.4 times and 13.0 ± 0.8 weeks, and as for conventional group they were 130.0 ± 5.8 minutes, 105.1 ± 5.6 minutes, 11.7 ± 1.5 ml, 22.2 ± 2.4 times and 13.3 ± 0.8 weeks, respectively (p < 0.0001). The both groups significantly restored Bohler angle, Gissane angle, calcaneal width and calcaneal facet height after operation (p < 0.0001). The 3D model-assisted group was significantly more succesful in restoration and protection of achieved correction of calcanel facet height (p < 0.0001). The difference was determined among the groups at the final follow-up examination with respect to the amount of change according the values achieved post-op. were significant in Bohler angle (p < 0.001), calcaneal facet height (p < 0.0001) and calcaneal widht (p = 0.017). There was no significant difference between AOFAS scores of the two groups at last follow-up. Resident doctors exhibited high scores of overall satisfaction with the use of a 3D printing model.

CONCLUSIONS

Compared to the conventional group, the 3D model-assisted group provide successful intervention and reduce operation, instrumentation time and the fluoroscopy usage with less blood loss. Performing 3D-assisted surgery helps the quality of reduction during the surgery and stability of internal fixation to protect achieved reduction at follow-up more succesfully.

Optimizing femur symmetry judgment using three-dimensional data correction scheme in fractures of the proximal femur

BACKGROUND

The application of the 3D printing mirror image model is based on the symmetry of the limbs. Different from image fusion to judge the similarity, based on the commonality of the limb morphology of the same organism and the isotropic of the long bone cross-section, the symmetry of the femur has been determined by calculating the dimension difference of the corresponding cross-section of the non-fractured area. However, the previous version used equidistant cross-sections for measurement and two-dimensional data correction, and there were problems with insufficient reliability and data failure. The purpose of this study is to achieve a more accurate and universal symmetry verification scheme for bilateral tubular bones through an improved method.

METHODS

Forty-five imaging data of proximal femoral fracture and osteopathy were selected from October 2015 to September 2017. 10%, 30%, and 50% of the full-length of the bilateral femur is sliced to judge the similarity between paired femurs. Long and short axes of the bilateral femoral cross-sections on the two-dimensional slices were measured and compared. A stylized trigonometric were used to correct the measured axes lengths such that they more closely match with measurements taken from slices perpendicular to femoral shaft axis.

RESULTS

540 valid data items from the long axis and short axis of the bilateral side of the distal femur were obtained, and 192 of these were corrected. There were no significant differences between the left and right of the long and short axis of each cross-section in paired cases (P>0.05).

CONCLUSIONS

This study have demonstrated symmetricity of the left and right femurs. The availability of CT data at any position of the patient's lower limbs is realized through replacing the previous "two-dimensional data correction" with "three-dimensional data correction".

A Review on Development of Bio-Inspired Implants Using 3D Printing

Biomimetics is an emerging field of science that adapts the working principles from nature to fine-tune the engineering design aspects to mimic biological structure and functions. The application mainly focuses on the development of medical implants for hard and soft tissue replacements. Additive manufacturing or 3D printing is an established processing norm with a superior resolution and control over process parameters than conventional methods and has allowed the incessant amalgamation of biomimetics into material manufacturing, thereby improving the adaptation of biomaterials and implants into the human body. The conventional manufacturing practices had design restrictions that prevented mimicking the natural architecture of human tissues into material manufacturing. However, with additive manufacturing, the material construction happens layer-by-layer over multiple axes simultaneously, thus enabling finer control over material placement, thereby overcoming the design challenge that prevented developing complex human architectures. This review substantiates the dexterity of additive manufacturing in utilizing biomimetics to 3D print ceramic, polymer, and metal implants with excellent resemblance to natural tissue. It also cites some clinical references of experimental and commercial approaches employing biomimetic 3D printing of implants.

3D printing-assisted extended lateral approach for displaced intra-articular calcaneal fractures: a systematic review and meta-analysis

BACKGROUND

Three-dimensional (3D) printing technology has developed rapidly in orthopaedic surgery and effectively achieves precise and personalized surgery. The purpose of this meta-analysis was to assess the efficacy of 3D printing technology in the management of displaced intra-articular calcaneal fractures (DICFs) by extended lateral approach (ELA).

METHODS

We searched PubMed, Web of Science, Embase, Cochrane Library, CNKI, VIP, and VANFUN databases were searched up to October 2020. All clinical studies comparing traditional surgery and 3D printing-assisted surgery in the management of DICFs were obtained, evaluating the quality of the included studies and extracting data. For each study, we assessed odds ratios (ORs), standard mean difference (SMD), and 95% confidence interval (95% CI) to assess and synthesize the outcomes.

RESULTS

Three RCTs and nine retrospective studies involving 732 patients were included met our inclusion criteria with 366 patients in the 3D group and 366 patients in the conventional group. The meta-analysis showed that there were significant differences of the operative time in the 3D group [SMD =  - 1.86, 95% CI (- 2.23, - 1.40), P < 0.001], intraoperative blood loss [SMD =  - 1.26, 95% CI (- 1.82, - 0.69), P < 0.001], the number of intraoperative X-ray exposures [SMD =  - 0.66, 95% CI (- 1.20, - 0.12), P < 0.001], postoperative complications [OR = 0.49, 95% CI (0.31, 0.79), P < 0.001], excellent and good rate of calcaneal fracture outcome [OR = 4.09, 95% CI (2.03, 8.22), P < 0.001].

CONCLUSION

The current study indicates that 3D printing-assisted ELA surgery showed a better rate of excellent and good outcome, shorter operation time, less intraoperative blood loss, fewer intraoperative fluoroscopies, fewer complications. Besides, there is still a need for large-sample, high-quality, long-term randomized controlled trials to confirm the conclusion.

Preoperative Planning Using 3D Printing Technology in Orthopedic Surgery

The applications of 3D printing technology in health care, particularly orthopedics, continue to broaden as the technology becomes more advanced, accessible, and affordable worldwide. 3D printed models of computed tomography (CT) and magnetic resonance image (MRI) scans can reproduce a replica of anatomical parts that enable surgeons to get a detailed understanding of the underlying anatomy that he/she experiences intraoperatively. The 3D printed anatomic models are particularly useful for preoperative planning, simulation of complex orthopedic procedures, development of patient-specific instruments, and implants that can be used intraoperatively. This paper reviews the role of 3D printing technology in orthopedic surgery, specifically focusing on the role it plays in assisting surgeons to have a better preoperative evaluation and surgical planning.

Percutaneous reduction, cannulated screw fixation and calcium sulfate cement grafting assisted by 3D printing technology in the treatment of calcaneal fractures

BACKGROUND

Percutaneous reduction, cannulated screw fixation and calcium sulfate cement grafting (PR + CSC) for treatment of displaced and intra-articular calcaneal fractures (DIACFs) is a difficult technique, because the minimally invasive treatment has limited exposure and cannot be used to reduce articular surface under direct vision. The goal of this study was to apply 3D printing technology to preoperative planning and surgery of DIACFs, and to evaluate its effectiveness, feasibility and safety in fracture repair.

METHODS

We enrolled 81 patients with DIACFs in the study from August 2015 to August 2017. Patients with DIACFs in our hospital were randomly divided into the 3D printing group (40 cases) and the conventional group (41 cases). The operation duration, blood loss volume and the number of fluoroscopy were compared. Radiological results were evaluated using radiographs and functional results were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) score. The complications were also assessed. In addition, we made a questionnaire to verify the usefulness of the 3D printed model for both doctors and patients.

RESULTS

The operation duration, blood loss volume and the number of fluoroscopy in 3D printing group were significantly less than that in the conventional group. Besides, 3D printing group achieved significantly better radiological results than conventional group both postoperatively and at the final follow-up except the calcaneal width at the final follow-up. The AOFAS score in the 3D printing group was significantly higher than that in the conventional group. In addition, the questionnaire from doctors and patients exhibited high scores of overall satisfaction of the 3D printed models. As for complications, there was no significant difference among the two groups.

CONCLUSION

This study suggested the clinical feasibility of PR + CSC assisted by 3D printing technology in the treatment of DIACFs.

LEVEL OF EVIDENCE

II.

Calcaneal fractures: 3D-printing model to assist spatial weaving of percutaneous screws versus conventional open fixation-a retrospective cohort study

PURPOSE

This study compared the clinical effectiveness and wound complications of a three-dimensional model-assisted spatial weaving screw fixation (3D-SWSF) versus open reduction and internal fixation (ORIF) via an L-shaped extensile lateral approach for calcaneal fractures.

METHODS

This single-centre retrospective cohort study was conducted with two cohort groups in which patients with Sanders II and III calcaneal fractures underwent 3D-SWSF or conventional ORIF. The clinical outcome measures included operation duration, time to operation, wound complications, blood loss volume, hospital stays, American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score, and visual analog scale (VAS) score. The pre-operative, post-operative, and one-year follow-up Gissane's angle (GA), Böhler's angle (BA), height, and width and length of the calcaneal fractures were also compared between the two groups.

RESULTS

From Oct 2015 to Oct 2019, 31 patients received 3D-SWSF and 41 received conventional ORIF. A total of 11 (26.8%) patients in ORIF group had wound complications, compared with only two (6.5%) in 3D-SWSF group (p = 0.032). Operative time, blood loss, and hospital stay in 3D-SWSF group were lesser than those in ORIF group. The patients treated with 3D-SWSF had better AOFAS and VAS scores than those treated with ORIF at the last follow-up. The post-operative and one-year follow-up radiographic indexes as well as the GA, BA, length, width, and height of the calcaneal fractures were relatively comparable between the two groups.

CONCLUSION

Our study revealed that 3D-SWSF could effectively decrease the risk of wound complications, shorten operation time, reduce length of hospitalization, and improve post-operative rehabilitation.

Custom Implants in TKA Provide No Substantial Benefit in Terms of Outcome Scores, Reoperation Risk, or Mean Alignment: A Systematic Review

BACKGROUND

Failure to accurately replicate the native anatomy and biomechanics of the knee has been suggested to contribute to dissatisfaction after TKA. Custom implants promise a personalized surgical approach, with the aim of improving patient satisfaction and pain as well as lowering revision rates. However, some published research on custom TKA implants has found no clinically important improvements in postoperative validated outcomes scores, risks of revision or reoperation, and implant alignment. In the interest of helping to settle this controversy, a systematic review seems warranted.

QUESTION/PURPOSE

In this systematic review, we asked whether custom implants result in clinically important improvements over conventional off-the-shelf implants for anatomically uncomplicated primary TKA in terms of (1) validated outcomes scores, (2) the risk of revision or reoperation, and (3) implant alignment.

METHODS

The US National Library of Medicine (PubMed/Medline), Embase, Web of Science, and Cochrane Database of Systematic Reviews were systematically searched to identify publications from the past 10 years relevant to this review. Publications that compared the clinical outcome measures, number of revisions and reoperations, and radiological assessment of implant alignment of custom and standard implants with validated endpoints were eligible for inclusion. In the interest of capturing as much potentially relevant information as possible, we applied no requirement for minimum follow-up duration. Clinical outcomes were assessed using patient-reported outcome (PROM) scores including the Knee Society Score (KSS), Forgotten Joint Score, and Knee Injury and Osteoarthritis Outcome Score. The risk for revision or reoperation were evaluated by the number of early and late manipulations, debridement procedures, and replacement of one or more components. Implant alignment was compared using postoperative deviation from the neutral (0°) mechanical axis of the limb and each component and the posterior tibial slope. All qualified studies were retrospective, and all compared custom implants with standard implants. Data on 1510 patients were reviewed (749 with custom implants and 761 with off-the-shelf implants). The mean follow-up time ranged from 12 to 33 months.

RESULTS

There was no apparent advantage to custom implants in terms of PROM scores. Of the five studies evaluating clinical outcomes, only one reported better KSS-Function scores at 3 months; two reported no difference, and two found inferior KSS scores. In several studies, custom implants were associated with more frequent reoperations than standard implants. Although in general there were no differences between custom and standard implants in terms of mean coronal plane limb alignment, one of seven studies found that the proportion of patients whose alignment was outside ± 3° from the neutral axis in the coronal plane was lower in the custom group than in the standard group.

CONCLUSION

With generally poorer outcomes scores for pain and function, generally higher risks of reoperation and reintervention, and no overall benefit to alignment, custom implants for primary TKA for the general population currently appear to be inferior to standard implants. Whether the slight reduction in the proportion of patients with alignment outliers observed in a minority of studies will result in a substantial reduction in revision risk over time must be addressed by future studies. However, until or unless such a reduction is proven, we recommend against the routine use of custom implants in practice because of increased costs and the risks associated with their novelty.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Can 3D-printing avoid discomfort-related implant removal in midshaft clavicle fractures? A four-year follow-up

INTRODUCTION

Due to the variation in shape and curvature of the clavicle, plates often have to be adjusted during surgery to acquire a good fit. Poorly fitted plates can cause discomfort, eventually requiring implant removal. 3D-printed replicas of the fractured clavicle can assist in planning of the surgical approach, plate selection and, if necessary, adjustment of the plate prior to surgery. We hypothesized this method of preoperative preparation would reduce implant-related discomfort resulting in a reduced reoperation rate MATERIALS AND METHODS: In a prospective cohort study, perioperative plate handling and clavicle fixation were timed and follow-up data were collected from participants undergoing operative treatment for a midshaft clavicle fracture. The control group (n = 7) received conventional surgery with standard precontoured plates. For the intervention group (n = 7), 3D-printed replicas of the fractured clavicle and a mirrored version of the healthy contralateral clavicle were available prior to surgery for planning of the surgical approach, and for plate selection and contouring. Primary outcome was reoperation rate due to implant-related discomfort. Secondary outcomes were complications and time differences in the different surgical phases (reduction, fixation and overall operation time) RESULTS: More participants in the control group had the plate removed due to discomfort compared to the intervention group (5/7 vs. 0/6; P = 0.012). One participant was excluded from the intervention group due to a postoperative complication; an infection occurred at the implant site. No relevant time difference in surgical plate handling was found between both groups.

CONCLUSIONS

Preoperative preparation using 3D-printed replicas of the clavicle fracture may reduce implant removal caused by plated-related discomfort. No relevant effect on surgery time was found.

TRIAL REGISTRATION

Registered with 'toetsingonline.nl', trial number NL51269.075/14, 17-02-2015.

Morphometric variations of the lateral surface of calcaneus: Can standard plate sizes fit all?

PURPOSE

Displaced intraarticular fractures of the calcaneum often require plate fixation. The complex fractures are usually fixed with standard lateral plates and are approached via the extensile lateral approach which is fraught with the risk of wound complications. Oversized calcaneal plates produce tension on the wound closure site and can, thus result in wound healing problems. The current study analyses the morphometry of the lateral surface of the calcaneus for the ideal configuration of the calcaneal plates for Indian patients using a CT based analysis of intact calcanei.

METHODS

Fifty CT based studies of normal calcanei were retrospectively analyzed using Horos® software version 3.3.5. The cross-section of the lateral third of calcaneum was assessed for the morphometric measurements relevant to the dimensions of the standard plating devices for calcaneum. We measured the overall plating length of calcaneum, the vertical heights at the anterior process and calcaneal tuberosity, the height of the posterior facet, the lengths of the anterior process, and the posterior facet. The inclination angles of the posterior facet, cuboid facet were also measured. The findings were compared between male and female cases.

RESULTS

The mean plating length of the calcaneus was 60.06 ± 4.05 mm. The mean vertical height of the anterior process and the calcaneal tuberosity were 24.3 ± 2.71 mm and 39.48 ± 4.73, respectively. The length of the anterior process and the posterior facet were 21.36 ± 1.72 and 25.02 ± 4.17, respectively. The mean Gissane angle and the angle of inclination of posterior facet in relation to the plating length were 118.04 ± 5.99° and 47.3 ± 5.20°. The mean anterior slant angle of the cuboid facet was 96.64 ± 4.39°. Significant differences were observed in the measurements among male and female groups except for the angular parameters.

CONCLUSION

The current analysis suggests the individual morphometric variations of the lateral plating surface of the calcaneus. Although female calcanei have smaller dimensions compared to male calcanei, the angular parameters are comparable among the two groups. Considering the wide variations in the majority of the morphometric parameters, it is difficult to standardize the plate dimensions. However, a few serial increments in the plate dimensions can help in providing the best fit rather than an ideal fit. Also, the plates should be available with multiple inclination angles of the facet limbs according to the local population variations.

A Review on 3D-Printed Templates for Precontouring Fixation Plates in Orthopedic Surgery

This paper is a systematic review of the literature on 3D-printed anatomical replicas used as templates for precontouring the fixation plates in orthopedic surgery. Embase, PubMed, Cochrane, Scopus and Springer databases were consulted for information on design study, fracture anatomical location, number of patients, surgical technique, virtual modeling approach and 3D printing process. The initial search provided a total of 496 records. After removing the duplicates, the title and abstract screening, and applying exclusion criteria and citations searching, 30 papers were declared eligible and included in the final synthesis. Seven studies were identified as focusing on retrospective non-randomized series of clinical cases, while two papers presented randomized case control studies. Two main approaches were highlighted in developing 3D-printed anatomical models for precontouring fixation plates: (a.) medical reconstruction, virtual planning and fracture reduction followed by 3D printing the model; (b.) medical reconstruction followed by 3D printing the model of the mirrored uninjured side. Revised studies reported advantages such as surgical time and blood loss reduction, while the reduction quality is similar with that of the conventional surgery. During the last couple of years there was an increase in the number of studies focused on precontouring orthopedic plates using 3D printing technology. Three-dimensionally-printed templates for plate precontouring were mostly used for acetabular fractures. Knowledge on medical virtual modeling and reconstruction is mandatory.

Finding NEEMO: towards organizing smart digital solutions in orthopaedic trauma surgery

There are many digital solutions which assist the orthopaedic trauma surgeon. This already broad field is rapidly expanding, making a complete overview of the existing solutions difficult.The AO Foundation has established a task force to address the need for an overview of digital solutions in the field of orthopaedic trauma surgery.Areas of new technology which will help the surgeon gain a greater understanding of these possible solutions are reviewed.We propose a categorization of the current needs in orthopaedic trauma surgery matched with available or potential digital solutions, and provide a narrative overview of this broad topic, including the needs, solutions and basic rules to ensure adequate use in orthopaedic trauma surgery. We seek to make this field more accessible, allowing for technological solutions to be clearly matched to trauma surgeons' needs. Cite this article: EFORT Open Rev 2020;5:408-420. DOI: 10.1302/2058-5241.5.200021.

3D printing in shoulder surgery

Three-dimensional (3D) printing is a novel modality with the potential to make a huge impact in the surgical field. The aim of this paper is to provide an overview on the current use of 3D printing in shoulder surgery. We have reviewed the use of this new method in 3 fields of shoulder surgery: shoulder arthroplasty, recurrent shoulder instability and orthopedic shoulder traumatology. In shoulder arthroplasty, several authors have shown that the use of the 3D printer improves the positioning of the glenoid component, even if longer clinical follow-up is needed to determine whether the cost of this system rationalizes the potential improved functional outcomes and decreases glenoid revision rates. In the treatment of anterior shoulder instability, the literature agrees on the fact that the use of the 3D printing can: enhance the dept and size of bony lesions, allowing a patient tailored surgical planning and potentially reducing operative times; allow the production of personalized implants to restore substantial bone loss; restore glenohumeral morphology and instability. In orthopedic trauma, the use of 3D printing can be helpful to increase the understanding of fracture patterns, facilitating a more personalized planning, and can be used for resident training and education. We can conclude the current literature regarding the use of 3D printed models in orthopedic surgery agrees finding objective improvements to preoperative planning and to the surgical procedure itself, by shortening the intraoperative time and by the possibility to develop custom-made, patient-specific surgical instruments, and it suggests that there are tangible benefits for its implementation.

Conventional vs 3-Dimensional Printed Cast Wear Comfort

Background: The objective of this study was to determine the functionality of 3-dimensional (3D) printed orthoses for upper extremity immobilization compared with conventional immobilization. Methods: Twelve healthy volunteers were fitted with a 3D custom printed short arm cast and a short arm fiberglass cast in separate sessions. The Jebsen Hand Function Test (JHFT) was used to test function and dexterity in each cast. All volunteers completed a modified version of the Patient-Rated Wrist Evaluation (PRWE). Skin complications were recorded. Results: There were no significant differences during the JHFT between casts, although one-third of the participants in the 3D cast could perform the tasks in a normal time, which they could not in the fiberglass cast. The average PRWE function score was lower in the 3D cast group than in the fiberglass group (45.5 vs. 80.8). Minor skin irritation was noted in 42% of patients in the fiberglass cast group compared with only 1 patient (8%) in the 3D cast group. One patient in the fiberglass group required a cast change due to inappropriate fit. Conclusions: Both casting techniques demonstrate similar objective function based on the JHFT. Patient satisfaction, comfort, and perceived function are superior in the 3D printed casts.

Clinical Application of 3-Dimensional Printed Navigation Templates in Treating Femoral Head Osteonecrosis With Pedicled Iliac Bone Graft

The aim of the study was to explore the feasibility and early effect of digital design combined with 3-dimensional (3D) printing technique in the transplantation of vascular pedicled iliac bone flap in the treatment of avascular necrosis of the femoral head.

Development of a 3-D Printing Laboratory for Foot and Ankle Applications

This article is a guide to starting a 3-dimensional (3-D) print laboratory; 3-D models of complicated foot and ankle pathology can enhance surgical planning, improve patient and medical trainee education, and aid in research. This article discusses the variables that must be considered when creating a 3-D printing laboratory, including the hardware, software, printing materials, and procedures. Herein is a basic outline of what is required to develop a foot and ankle 3-D printing laboratory.

From digital world to real life: a robotic approach to the esophagogastric junction with a 3D printed model

Background

Three-dimensional (3D) printing may represent a useful tool to provide, in surgery, a good representation of surgical scenario before surgery, particularly in complex cases. Recently, such a technology has been utilized to plan operative interventions in spinal, neuronal, and cardiac surgeries, but few data are available in the literature about their role in the upper gastrointestinal surgery. The feasibility of this technology has been described in a single case of gastroesophageal reflux disease with complex anatomy due to a markedly tortuous descending aorta.

Methods

A 65-year-old Caucasian woman was referred to our Department complaining heartburn and pyrosis. A chest computed tomography evidenced a tortuous thoracic aorta and consequent compression of the esophagus between the vessel and left atrium. A “dysphagia aortica” has been diagnosed. Thus, surgical treatment of anti-reflux surgery with separation of the distal esophagus from the aorta was planned. To define the strict relationship between the esophagus and the mediastinal organs, a life-size 3D printed model of the esophagus including the proximal stomach, the thoracic aorta and diaphragmatic crus, based on the patient’s CT scan, was manufactured.

Results

The robotic procedure was performed with the da Vinci Surgical System and lasted 175 min. The surgeons had navigational guidance during the procedure since they could consult the 3D electronically superimposed processed images, in a “picture-in-picture” mode, over the surgical field displayed on the monitor as well as on the robotic headset. There was no injury to the surrounding organs and, most importantly, the patient had an uncomplicated postoperative course.

Conclusions

The present clinical report highlights the feasibility, utility and clinical effects of 3D printing technology for preoperative planning and intraoperative guidance in surgery, including the esophagogastric field. However, the lack of published data requires more evidence to assess the effectiveness and safety of this novel surgical-applied printing technology.

[Current concepts and new developments of 3D printing in trauma surgery]

The use of 3D printing (synonyms "rapid prototyping" and "additive manufacturing") has played an increasing role in the industry for many years and finds more and more interest and application in musculoskeletal surgery, especially orthopedic trauma surgery.In this article the current literature is systematically reviewed, presented and evaluated in a condensed and comprehensive way according to anatomical (upper and lower extremities) and functional aspects. As many of the publications analyzed were feasibility studies, the degree of evidence is low and methodological weaknesses are obvious and numerous; however, this pioneering work is extremely stimulating and important for further development because the technical, medical and economic potential of this technology is huge and interesting for all those involved in the treatment of musculoskeletal problems.

Application of Three-Dimensional Printing Technology for Improved Orbital-Maxillary-Zygomatic Reconstruction

The reconstruction of orbital-maxillary-zygomatic complex (OMZC) on patients suffering from trauma and space-occupying lesions is challenging due to the irregularity of craniomaxillofacial bones. To overcome the challenge in precise OMZC reconstruction, individual three-dimensional (3D) disease models and mirror-imaged 3D reconstruction models were printed on the basis of the computer tomography. Preoperative planning by rehearsing surgical procedures was made on the 3D disease models and the scaffolds including titanium and absorbable meshes or plates were anatomically premolded using the mirror-imaged 3D models as guide. Many benefits were achieved including more precise OMZC reconstruction, fluent and smooth procedures of surgeries, shorter operation time, less blood loss, and improved cosmetic outcomes of craniomaxillofacial shapes. There were no complications such as diplopia, infection, foreign body reaction, exophthalmos, enophthalmos, disordered occlusal relationship, and hematoma. And patients were satisfied with the functional and esthetic outcome during the following-up time. Therefore, OMZC reconstruction can be optimized and successful through preoperative planning and premolded scaffolds with 3D printing bone model by computer-aid design and manufacturing.

Are Three-Dimensional Printed Models Useful for Preoperative Planning of Tibial Plafond Fractures?

Computed tomography (CT) scans with 3-dimensional (3D) reconstruction are the gold standard of imaging for complex fractures. However, visualising CT imaging can be challenging. With increasing access to 3D printing, we postulate that life-sized 3D models can better assist in visualising CT images, aiding preoperative planning of tibial plafond fractures. 3D models of 3 tibial plafond fractures of differing complexities were printed. We approached surgeons in our institution who manage tibial plafond fractures to complete a questionnaire on preoperative planning of the cases based on CT scans. We then examined whether analysing the 3D models after that changed the plan. This included ratings on the usefulness, accuracy, and ease of use of the models. Six surgeons participated in the study. In the simple fracture model, median usefulness was graded as 4.5 (range minimum to maximum: 0 to 7), accuracy 8 (4 to 10), and ease of use 9 (7 to 10) with 0 being the lowest and 10 being the upper limit of how useful, accurate, or easy to use the models were. For the intermediate fracture, median usefulness was 6.5 (2 to 8), accuracy 7.5 (3 to 10), and ease of use 8.5 (7 to 10). For the complex fracture, median usefulness was 6 (1 to 9), accuracy 7.5 (1 to 9), and ease of use 8.5 (0 to 9). We attribute these poorer scores to difficulty in processing the scans, resulting in less accurate printing of the many fragments in complex impacted fractures. In conclusion, 3D-printed models are easy to use and accurate in preoperative planning of tibial plafond fractures. Most surgeons believe that 3D models and CT scans combined were more useful than CT scans alone.

Efficacy and Prognosis of 3D Printing Technology in Treatment of High-Energy Trans-Syndesmotic Ankle Fracture Dislocation - "Log-Splitter" Injury

Background

This study aimed to retrospectively assess the feasibility and efficacy of three-dimensional (3D) printing technology in the treatment of high-energy trans-syndesmotic ankle fracture dislocation – “log-splitter” injury – and to evaluate the efficacy and prognosis.

Material/Methods

We included 29 patients (17 males and 12 females; mean age, 44.0±13.2 years) with log-splitter injury from June 2011 to December 2016, divided into a routine group (n=13) and a 3D printing group (n=16) according to the surgical method used. Operation time, intraoperative blood loss, fluoroscopy times, fracture union time, functional outcomes based on AOFAS (American Orthopedic Foot and Ankle Society) score, and postoperative complications were observed and recorded.

Results

Compared with the routine treatment group, 3D printing technology had better safety and efficacy for the treatment of log-splitter injury and the advantages of shorter operation time, less intraoperative blood loss, fewer fluoroscopies needed, and higher rate of good functional outcome (P<0.001, P<0.001, P<0.001, and P=0.017, respectively). However, no significant difference was noted in the rate of anatomical reduction, mean AOFAS score at the last follow-up (mean time, 19.9±2.8 months), or postoperative complications between the 2 groups (P=0.370, P=0.156, and P=0.485, respectively).

Conclusions

Surgery assisted by 3D printing technology to treat log-splitter injury is feasible and effective, and may be a good optional approach to formulate a reasonable personalized surgical plan and to optimize the outcomes.

Clinical application of 3D printing technology to the surgical treatment of atlantoaxial subluxation in small breed dogs

Atlantoaxial instability (AAI)/subluxation commonly occurs in small breed dogs. Ventral stabilization techniques using screws and/or pins and a plate or, more commonly, polymethylmethacrylate are considered to provide the most favorable outcome. However, the implantation of screws of sufficient sizes for long-term stability becomes challenging in toy breed dogs (e.g. <2 kg). We herein report the application of 3D printing technology to implant trajectory planning and implant designing for the surgical management of AAI in 18 dogs. The use of our patient-specific drill guide templates resulted in overall mean screw corridor deviations of less than 1 mm in the atlas and axis, which contributed to avoiding iatrogenic injury to the surrounding structures. The patient-specific titanium plate was effective for stabilizing the AA joint and provided clinical benefits to 83.3% of cases (15/18). Implant failure requiring revision surgery occurred in only one case, and the cause appeared to be related to the suboptimal screw-plate interface. Although further modifications are needed, our study demonstrated the potential of 3D printing technology to be effectively applied to spinal stabilization surgeries for small breed dogs, allowing for the accurate placement of screws and minimizing peri- and postoperative complications, particularly at anatomical locations at which screw corridors are narrow and technically demanding.

Can Preoperative 3D Printing Change Surgeon's Operative Plan for Distal Tibia Fracture?

This study aimed to determine if 3D printing can affect surgeon's selection of plate for distal tibia fracture surgery and to find out whether orthopedic surgeons consider this technology necessary and would use it in their practice. A total of 102 orthopedic surgeons were asked to choose anatomically contoured locking plates among 5 most commonly used types for one simple and one complex distal tibia fracture based on X-ray and CT images. Next, they were provided real-size 3D printed models of the same fractures, allowed to apply each of the 5 plates to these models, and asked if they would change their choice of plate. A 10-point numeric rating scale was provided to measure the extent of the help that 3D printing provided on preoperative planning. Finally, we asked the surgeons if they would use 3D printing in their practice. Seventy-four percent of inexperienced surgeons changed their selection of plate after using 3D printed models for the complex fracture. In contrast, only 9% of experienced surgeons changed their selection of plate for the simple fracture. Surgeons rated the extent of usefulness of the 3D models in preoperative planning as a mean of 4.84 ± 2.54 points for the simple fracture and 6.63 ± 2.54 points for the complex fracture. The difference was significant (p < 0.001). Eighty-six percent of inexperienced surgeons wanted to use 3D models for complex fractures. However, only 18% of experienced surgeons wanted to use 3D printed models for simple fractures. The use of a real-size 3D-printed model often changed surgeon's preoperative selection of locking plates, especially when inexperienced surgeons evaluated a complex fracture. However, experienced surgeons did not find 3D models very useful when assessing simple fractures. Future applications of 3D models should focus on training beginners in fracture surgery, especially when complex fractures are concerned.

Current status and challenges of Additive manufacturing in orthopaedics: An overview

Additive manufacturing is a rapidly emerging technology which is being successfully implemented in the various field of medicine as well as in orthopaedics, where it has applications in reducing cartilage defects and treatments of bones. The technology helps through systematic collection of information about the shape of the "defects" and precise fabrication of complex 3D constructs such as cartilage, heart valve, trachea, myocardial bone tissue and blood vessels. In this paper, a large number of the relevant research papers on the additive manufacturing and its application in medical specifically orthopaedics are identified through Scopus had been studied using Bibliometric analysis and application analysis is undertaken. The bibliometric analysis shows that there is an increasing trend in the research reports on additive manufacturing applications in the field of orthopaedics. Discussions are on using technological advancement like scanning techniques and various challenges of the orthopaedic being met by additive manufacturing technology. For patient-specific orthopaedic applications, these techniques incorporate clinical practice and use for effective planning. 3D printed models printed by this technology are accepted for orthopaedic surgery such as revision of lumbar discectomy, pelvic surgery and large scapular osteochondroma. The applications of additive manufacturing in orthopaedics will experience a rapid translation in future. An orthopaedic surgeon can convert need/idea into a reality by using computer-aided design (CAD) software, analysis software to facilitate the manufacturing. Thus, AM provides a comprehensive opportunity to manufacture orthopaedic implantable medical devices.

Using 3D models in orthopedic oncology: presenting personalized advantages in surgical planning and intraoperative outcomes

Background

Three Dimensional (3D) printed models can aid in effective pre-operative planning by defining the geometry of tumor mass, bone loss, and nearby vessels to help determine the most accurate osteotomy site and the most appropriate prosthesis, especially in the case of complex acetabular deficiency, resulting in decreased operative time and decreased blood loss.

Methods

Four complicated cases were selected, reconstructed and printed. These 4 cases were divided in 3 groups of 3D printed models. Group 1 consisted of anatomical models with major vascular considerations during surgery. Group 2 consisted of an anatomical model showing a bone defect, which was intended to be used for substantial instrumentation, pre-operatively. Group 3 consisted of an extra-compartmental bone tumor which displayed a deteriorated cortical outline; thus, using CT and MRI fused images to reconstruct the model accurately. An orthopedic surgeon created the 3D models of groups 1 and 2 using standard segmentation techniques. Because group 3 required complex techniques, an engineer assisted during digital model construction.

Results

These models helped to guide the orthopedic surgeon in creating a personalized pre-operative plan and a physical simulation. The models proved to be beneficial and assisted with all 4 cases, by decreasing blood loss, operative time and surgical incision length, and helped to select the appropriate acetabular supporting ring in complex acetabular deficiency, pre-operatively.

Conclusion

Qualitatively, using 3D printing in tumor cases, provides personalized advantages regarding the various characteristics of each skeletal tumor.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Three-Dimensional Correction of Complex Ankle Deformities With Computer-Assisted Planning and Patient-Specific Surgical Guides

Three-dimensional computer-assisted preoperative planning, combined with patient-specific surgical guides, has become an effective technique for treating complex extra- and intraarticular bone malunions by corrective osteotomy. The feasibility and accuracy of such a technique has not yet been evaluated for ankle deformities. Four surgical cases of varying complexity and location were selected for evaluation. Three-dimensional bone models of the affected and contralateral healthy lower limb were generated from computed tomography scans. The preoperative planning software permitted quantification of the deformity in 3 dimensions and subsequent simulation of reduction, yielding a precise surgical plan. Patient-specific surgical guides were designed, manufactured, and finally applied during surgery to reproduce the preoperative plan. Evaluation of the postoperative computed tomography scans indicated adequate reduction accuracy with residual translational and rotational errors of <3 mm and <6°, respectively. Two patients required revision surgery owing to anterior osseous impingement or delayed union of the osteotomy. All patients were satisfied with the postoperative course and were pain free at a mean follow-up period of 2.5 (range 1 to 4) years. These promising results require confirmation in a clinical study with a larger sample size.

3D printing and its applications in orthopaedic trauma: A technological marvel

BACKGROUND

With rapid emergence of 3D printing technology, surgeons have recently started to apply this for nearly all areas of orthopaedic trauma surgery. Computed tomography or magnetic resonance images of trauma patients can be utilized for making graspable objects from 3D reconstructed images. Patient specific anatomical models can thereby be created. They enhance surgeon's knowledge of their patients' precise patho-anatomy, regarding both traumatized bones and soft tissue as well as normal areas, and therefore help in accurate preoperative planning. 3D printed patient specific instrumentation can help to achieve precise implant placement, and better surgical results. Most importantly, customized implants, casts, orthoses and prosthetics can be manufactured to match an individual's anatomy. Three dimensional (3D) printing, also called as 'additive manufacturing' and 'rapid prototyping' is considered as the "second industrial revolution", and this appears to be especially true for orthopaedic trauma surgery.

METHODS

A literature search was performed for extracting all papers related to 3D Printing applications in orthopaedics and allied sciences on the Pubmed, and SCOPUS; using suitable key terms and Boolean operators ("3D Printing" OR "3 dimensional printing" OR "3D printed" OR "additive manufacturing" OR "rapid prototyping") AND (''Orthopaedics" OR "Orthopaedics'') AND ("Trauma" OR "Injury")in June 2018. Search was also performed in Web of Science, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews. No limits were set on the time period or evidence level, as 3D printing in orthopaedics is relatively recent and mainly low level evidence is available. Titles and abstracts were screened and all duplicate and unrelated papers were excluded. Papers related to orthopaedic trauma were manually selected for this review.

RESULTS

The search on Pubmed retrieved 144 Papers and similar search on SCOPUS retrieved 94 papers. Additional searches did not reveal more relevant papers. After excluding duplicates and unrelated papers, and on screening of titles and abstracts, 59 papers were considered for review. Papers related to spine fractures only were not included, as they have been covered in another paper in this journal issue.

CONCLUSION

All over the world, orthopaedic Surgeon's and allied professionals and scientists are enthusiastically using 3D printing technology for designing patient specific models, instrumentation, implants, orthosis and prosthesis, besides 3D bioprinting of bone and cartilage scaffolding, and the same has been applied for nearly all areas of orthopaedic trauma surgery, from head to foot.

Preoperative Use of a 3D Printed Model for Femoroacetabular Impingement Surgery and Its Effect on Planned Osteoplasty

OBJECTIVE

The purpose of this study was to determine the effect that preoperative use of 3D printed models has on planned osteoplasty for femoroacetabular impingement (FAI) surgery.

MATERIALS AND METHODS

This experimental study utilizing retrospective data included 10 consecutive patients from July 1, 2013, to January 1, 2015, with a clinical diagnosis of FAI and imaging consisting of radiographs, CT scans, and MR images. Three-dimensional models of each patient's affected hip were printed to scale from CT data. Two orthopedic surgeons evaluated each patient in a routine preoperative manner. The effect of the 3D models in altering the planned osteoplasty was then determined. Proportions of osteoplasty change were calculated at various positions, and categoric variables were assessed with the chi-square test for independence.

RESULTS

Proportions of osteoplasty changes ranged from 20% to 55% at femoral positions (greatest at lateral and depth positions) and 35-75% at acetabular positions (greatest at anterior and depth positions). More osteoplasty changes occurred in patients with alpha angles of 60° or more (p = 0.00030) and without a radiographic crossover sign (p = 0.0075). We found no difference in the proportion of osteoplasty changes when stratifying by lateral center edge angle and coxa profunda (p = 0.190 and 0.109, respectively). The planned osteoplasty was changed for at least one reader in 9/10 (90%) femurs and 10/10 (100%) acetabula.

CONCLUSION

Use of 3D models in preoperative planning can change both the extent and location of planned osteoplasty for FAI surgery and is particularly influential in patients with alpha angles of 60° or more and without a radiographic crossover.

Use of a life-size three-dimensional-printed spine model for pedicle screw instrumentation training

Background

Training beginners of the pedicle screw instrumentation technique in the operating room is limited because of issues related to patient safety and surgical efficiency. Three-dimensional (3D) printing enables training or simulation surgery on a real-size replica of deformed spine, which is difficult to perform in the usual cadaver or surrogate plastic models. The purpose of this study was to evaluate the educational effect of using a real-size 3D-printed spine model for training beginners of the free-hand pedicle screw instrumentation technique. We asked whether the use of a 3D spine model can improve (1) screw instrumentation accuracy and (2) length of procedure.

Methods

Twenty life-size 3D-printed lumbar spine models were made from 10 volunteers (two models for each volunteer). Two novice surgeons who had no experience of free-hand pedicle screw instrumentation technique were instructed by an experienced surgeon, and each surgeon inserted 10 pedicle screws for each lumbar spine model. Computed tomography scans of the spine models were obtained to evaluate screw instrumentation accuracy. The length of time in completing the procedure was recorded. The results of the latter 10 spine models were compared with those of the former 10 models to evaluate learning effect.

Results

A total of 37/200 screws (18.5%) perforated the pedicle cortex with a mean of 1.7 mm (range, 1.2–3.3 mm). However, the latter half of the models had significantly less violation than the former half (10/100 vs. 27/100, p < 0.001). The mean length of time to complete 10 pedicle screw instrumentations in a spine model was 42.8 ± 5.3 min for the former 10 spine models and 35.6 ± 2.9 min for the latter 10 spine models. The latter 10 spine models had significantly less time than the former 10 models (p < 0.001).

Conclusion

A life-size 3D-printed spine model can be an excellent tool for training beginners of the free-hand pedicle screw instrumentation.

The precision and reliability evaluation of 3-dimensional printed damaged bone and prosthesis models by stereo lithography appearance

Recently, clinical application of 3D printed model was increasing. However, there was no systemic study for confirming the precision and reliability of 3D printed model. Some senior clinical doctors mistrusted its reliability in clinical application. The purpose of this study was to evaluate the precision and reliability of stereolithography appearance (SLA) 3D printed model.Some related parameters were selected to research the reliability of SLA 3D printed model. The computed tomography (CT) data of bone/prosthesis and model were collected and 3D reconstructed. Some anatomical parameters were measured and statistical analysis was performed; the intraclass correlation coefficient (ICC) was used to was used to evaluate the similarity between the model and real bone/prosthesis. the absolute difference (mm) and relative difference (%) were conducted. For prosthesis model, the 3-dimensional error was measured.There was no significant difference in the anatomical parameters except max height (MH) of long bone. All the ICCs were greater than 0.990. The maximum absolute and relative difference were 0.45 mm and 1.10%; The 3-dimensional error analysis showed that positive/minus distance were 0.273 mm/0.237 mm.The application of SLA 3D printed model in diagnosis and treatment process of complex orthopedic disease was reliable and precise.

Three-dimensional Technologies in Orthopedics

New 3-dimensional digital technologies are revolutionizing orthopedic clinical practice, allowing structures of any complexity to be manufactured in just hours. Such technologies can make surgery for complex cases more precise, more cost-effective, and possibly easier to perform. Applications include pre-operative planning, surgical simulation, patient-specific instrumentation and implants, bioprinting, prosthetics, and orthotics. The basic principles of 3- dimensional technologies, including imaging, design, numerical simulation, and printing, and their current applications in orthopedics are reviewed. [Orthopedics. 2018; 41(1):12-20.].

Clinical Applications of 3D Printing: Primer for Radiologists

Three-dimensional (3D) printing refers to a number of manufacturing technologies that create physical models from digital information. Radiology is poised to advance the application of 3D printing in health care because our specialty has an established history of acquiring and managing the digital information needed to create such models. The 3D Printing Task Force of the Radiology Research Alliance presents a review of the clinical applications of this burgeoning technology, with a focus on the opportunities for radiology. Topics include uses for treatment planning, medical education, and procedural simulation, as well as patient education. Challenges for creating custom implantable devices including financial and regulatory processes for clinical application are reviewed. Precedent procedures that may translate to this new technology are discussed. The task force identifies research opportunities needed to document the value of 3D printing as it relates to patient care.

Can the recovery of lower limb fractures be achieved by use of 3D printing mirror model?

INTRODUCTION

The mirror imaging 3D printing model can be used a as a reference for anatomical reduction in unilateral lower limb fractures. However, the premise of using mirror technology is that the bilateral lower limb bones are similar enough. Because one side had a fracture, it was impossible to compare this directly to the other side. Usually, surgeons think that the bilateral bones are symmetrical and use mirror technology without judging their symmetry.

METHODS

In patients with a unilateral lower limb bone fracture, we measured the long axis and short axis of the three selected transverse sections of the bilateral long bone for comparison to judge the symmetry of the bilateral long bones on CT images. Then, we printed a life-size normal mirror image of the long bone that is similar to the affected side. The model was used as a reference for the anatomical reduction of fractures and preoperative practice.

RESULTS

Seventy-eight patients with lower limb bone fracture were included in this study. 24 groups of data were generated according to the same level and same axis. There were significant differences between the short axis of the left and right femoral condyle 5cm from the intercondylar keel (p=0.011), and the short axis of the distal tibia 15cm from the ankle dome (p=0.026). There was no significant difference between the left and right sides in the other 22 groups. Of all of the patients in our research, 3 patients decided to forego the surgical treatment and the operation was performed on the model instead, and the lengths of 2 patients showed deviation in actual operations, preventing anatomical reduction. The remaining 73 patients used the pre-bended plates and screws from preoperative practice in the actual operations, and postoperative X-ray examinations showed that the length of the deviation was within the permissible range.

CONCLUSION

The "Comparison of long axis and short axis of three equidistant transverse sections" method makes it easy to judge the symmetry of the bilateral long bones, and prevents the blindness of preoperative planning using the contralateral mirror model directly.

3D Printing Calcaneal Fractures: Continuously Improving our Care by Making a Complex Problem Tangible

Calcaneal fractures are amongst the most complex injuries known to man. Their intricate anatomy and extensive damage after trauma make them difficult to understand and treat. Most surgeons specialized in foot and ankle trauma agree that in most patients surgical managements yields the best result. Functional outcome is largely dependent on preventing complications and restoring anatomy. Reconstruction of height and suntalar joint congruency for example are both associated with improved outcome. Over the years insight in the complex (patho-)anatomy has increased. First by conventional radiographs, later with computed tomography. Recently 3D scans and prints have been added to this armamentarium. The study in the current issue of the Journal of Investigative Surgery explores the use of 3D printed calcaneal fractures and the effect on restoring anatomy and functional outcome. An invited short commentary was provided.

Comparison of conventional reconstruction plate versus direct metal laser sintering plate: an in vitro mechanical characteristics study

BACKGROUND

Additive manufacturing (AM) technology has helped to achieve several advances in the medical field, particularly as far as fabrication of implants is concerned. But the application of direct metal laser sintering (DMLS) bone plate is quite limited due to the indeterminate mechanical property. The purposes of this study were to characterize the biomechanical properties of the polished DMLS reconstruction plate and to compare these with the properties of commonly applied implants and to find whether the mechanical performance of DMLS plate meets the requirements for clinical application.

METHODS

In this study, we fabricated two groups of plates by DMLS and computer numerical control (CNC) techniques. After that, we polished all samples and investigated their roughness, components, hardness, static bending, and torsional performance. Moreover, cyclic bending tests and fractographic analysis were conducted. Statistical comparisons of the group by means of monotonic test data were made, and a qualitative comparison was performed to assess failures in fatigue.

RESULTS

We found no differences in surface roughness or components after polishing, but the DMLS plate hardness is 7.42% (p < 0.01) greater than that of the CNC plates. Compared with the CNC plates, the DMLS plate static bending and torsional performance were significantly greater. In a dynamic test, the DMLS plates survived 106, 106, 32,731, and 33,264 cycles under 0.6, 0.8, 0.9, and 1 kN cyclic loads, respectively, while the CNC plates survived 106, 106, 106, and 283,714 cycles.

CONCLUSIONS

These results indicate that the mechanical performances of the DMLS plate are stronger, and the strength under fatigue tests is sufficient. DMLS implant has great potential and may become a better choice for clinical use in the future. However, direct application of these AM instruments in the operating room requires further validation including animal and clinical experiment.

Surgical applications of three-dimensional printing: a review of the current literature & how to get started

Three dimensional (3D) printing involves a number of additive manufacturing techniques that are used to build structures from the ground up. This technology has been adapted to a wide range of surgical applications at an impressive rate. It has been used to print patient-specific anatomic models, implants, prosthetics, external fixators, splints, surgical instrumentation, and surgical cutting guides. The profound utility of this technology in surgery explains the exponential growth. It is important to learn how 3D printing has been used in surgery and how to potentially apply this technology. PubMed was searched for studies that addressed the clinical application of 3D printing in all surgical fields, yielding 442 results. Data was manually extracted from the 168 included studies. We found an exponential increase in studies addressing surgical applications for 3D printing since 2011, with the largest growth in craniofacial, oromaxillofacial, and cardiothoracic specialties. The pertinent considerations for getting started with 3D printing were identified and are discussed, including, software, printing techniques, printing materials, sterilization of printing materials, and cost and time requirements. Also, the diverse and increasing applications of 3D printing were recorded and are discussed. There is large array of potential applications for 3D printing. Decreasing cost and increasing ease of use are making this technology more available. Incorporating 3D printing into a surgical practice can be a rewarding process that yields impressive results.

Three-dimensional printing for preoperative planning of total hip arthroplasty revision: case report

Three dimensional (3D) printing can be used to create material models to aid preoperative planning of complex orthopedic procedures as exemplified by this case of total hip arthroplasty failure due to infection with resulting severe acetabular bone stock deficiency. The 3D model allowed for trialing of the acetabular component to determine cup size, position, and screw placement. Most importantly, the model confirmed that there was not a pelvic discontinuity and the revision shell would be sufficient for the reconstruction. Previously, the cost and complexity of utilization of 3D printers were prohibitive. Recent improvements in commercially available 3D printers have made rapid prototype model creation a realistic option, which can facilitate difficult surgery.

From 3-Dimensional Printing to 5-Dimensional Printing: Enhancing Thoracic Surgical Planning and Resection of Complex Tumors

PURPOSE

Three-dimensional (3D) printing of anatomic models for complex surgical cases improves patient and resident education, operative team planning, and guides the operation. Our group describes two additional dimensions.

DESCRIPTION

The process of 5-dimensional (5D) printing was developed for surgical planning. Pretreatment computed tomography and positron emission tomography scans were reformatted and fused. Selected anatomy from these studies, along with posttreatment computed tomography and magnetic resonance images, were coregistered and segmented. This fused anatomy was converted into stereolithography files for 3D printing.

EVALUATION

A patient presenting with a complex thoracic tumor was selected for 5D printing. 3D and 5D models were prepared to allow surgical teams to directly evaluate and compare the added benefits of information provided by printing in 5 dimensions.

CONCLUSIONS

Printing 5D models in patients with complex thoracic pathology facilitates surgical planning, selecting margins for resection, anticipating potential difficulties, teaching for learners, and education for patients.

Three-dimensional printing in orthopaedic surgery: review of current and future applications

Three-dimensional (3D) printing is a rapidly evolving technology with the potential for significant contributions to surgical practice. There are many current applications for 3D printing technology with future applications being explored. This technology has applications in preoperative planning, education, custom manufacturing (implants, prosthetics and surgical guides) and exciting potential for biological applications. This article reviews the current and future applications of 3D technology in orthopaedic surgery.

Three-Dimensional Printing and Surgical Simulation for Preoperative Planning of Deformity Correction in Foot and Ankle Surgery

A paucity of published data is available describing the methods for the integration of 3-dimensional (3D) printing technology and surgical simulation into orthopedic surgery. The cost of this technology has decreased and the ease of use has increased, making routine use of 3D printed models and surgical simulation for difficult orthopedic problems a realistic option. We report the use of 3D printed models and surgical simulation for preoperative planning and patient education in the case of deformity correction in foot and ankle surgery using open source, free software.