3D-printed Surgical Guides Research Articles

The Use of 3D-Printed Surgical Guides and Models for Sinus Lift Surgery Planning and Education

Aim: To develop 3D printing and dentistry methods for building physical models that enable one to simulate a sinus lift surgery. Materials & methods: The Blue Sky Plan software was used to create a digital model from the cone beam computed tomography scan of the subject’s maxilla and to design a surgical guide for sinus augmentation and implant placement. The anatomical model and surgical guide were 3D printed from dental resin. Results: Sinus augmentation and dental implant insertion were carried out on the model as examples of practical skills training for residents in maxillofacial surgery. Conclusion: The 3D-printed models and surgical guides are useful training materials. They could be helpful also in a dental practice for surgical planning and for illustrating the procedure to the patient.

MRI-based 3D-printed surgical guides for breast cancer patients who received neoadjuvant chemotherapy

Magnetic resonance imaging (MRI) is the most accurate technique for evaluating residual tumor after neoadjuvant chemotherapy. However, precise determination of the extent of dispersed residual tumor in the breast following treatment remains a difficult task. We hereby introduce three-dimensional (3D)-printed surgical guides for use in breast cancer patients undergoing breast-conserving surgery after receiving neoadjuvant chemotherapy. We prospectively applied the 3D-printed surgical guides on breast cancer patients who underwent partial breast resection after receiving neoadjuvant chemotherapy. Breasts and tumors were modeled in 3D by using pretreatment magnetic resonance images, and surgical guides were created by using a 3D printer to mark the primary tumor. Out of the five patients who participated in the study, all patients had clear resection margins, and two patients experienced complete pathological remission. There were no recurrences during the median follow-up period of 21.9 months. Thus, our newly-developed 3D-printed surgical guides were useful for accurately marking the extent of breast tumor based on pretreatment magnetic resonance images, which is important for designating the extent of surgery needed in patients who have received neoadjuvant chemotherapy.

3D-printed surgical guides

Conventional bone replacement surgeries have always been associated with different critical drawbacks. Deviation of the implant from its original position is one of the most important problems associated with surgery. The emergence of computer-aided design/computer-aided manufacturing technology opened a new opportunity for the solution of this problem by the use of patient-specific surgical guides. These 3D-printed surgical guides provide a specific cut and therefore reduces the drawbacks associated with surgical techniques including the fixation difficulties. In this review, 3D-printed guides for knee arthroplasty, pedicle screw placement and mandibular reconstruction will be discussed covering both the progress and the drawbacks.

Design and 3D printing customized guides for orthopaedic surgery – lessons learned

PurposeThis paper aims to fill a research gap by presenting design and 3D printing guidelines and considerations which apply to the development process of patient-specific osteotomy guides for orthopaedic surgery.Design/methodology/approachAnalysis of specific constraints related to patient-specific surgical guides design and 3D printing, lessons learned during the development process of osteotomy guides for orthopaedic surgery, literature review of recent studies in the field and data gathered from questioning a group of surgeons for capturing their preferences in terms of surgical guides design corresponding to precise functionality (materializing cutting trajectories, ensuring unique positioning and stable fixation during surgery), were all used to extract design recommendations.FindingsGeneral design rules for patient-specific osteotomy guides were inferred from examining each step of the design process applied in several case studies in relation to how these guides should be designed to fulfill medical and manufacturing (fused deposition modelling process) constraints. Literature was also investigated for finding other information than the simple reference that the surgical guide is modelled as negative of the bone. It was noticed that literature is focussed more on presenting and discussing medical issues and on assessing surgical outcomes, but hardly at all on guides’ design and design for additive manufacturing aspects. Moreover, surgeons’ opinion was investigated to collect data on different design aspects, as well as interest and willingness to use such 3D-printed surgical guides in training and surgery.Practical implicationsThe study contains useful rules and recommendations for engineers involved in designing and 3D printing patient-specific osteotomy guides.Originality/valueA synergetic approach to identify general rules and recommendations for the patient-specific surgical guides design is presented. Specific constraints are identified and analysed using three case studies of wrist, femur and foot osteotomies. Recent literature is reviewed and surgeons’ opinion is investigated.

Positioning error of custom 3D-printed surgical guides for the radius: influence of fitting location and guide design

PurposeUtilization of 3D-printed patient-specific surgical guides is a promising navigation approach for orthopedic surgery. However, navigation errors can arise if the guide is not correctly positioned at the planned bone location, compromising the surgical outcome. Quantitative measurements of guide positioning errors are rarely reported and have never been related to guide design and underlying bone anatomy. In this study, the positioning accuracy of a standard and an extended guide design with lateral extension is evaluated at different fitting locations (distal, mid-shaft and proximal) on the volar side of the radius.MethodsFour operators placed the surgical guides on 3D-printed radius models obtained from the CT scans of six patients. For each radius model, every operator positioned two guide designs on the three fitting locations. The residual positioning error was quantified with a CT-based image analysis method in terms of the mean target registration error (mTRE), total translation error (Delta T) and total rotation error (Delta R) by comparing the actual guide position with the preoperatively planned position. Three generalized linear regression models were constructed to evaluate if the fitting location and the guide design affected mTRE, Delta T and Delta R.ResultsmTRE, Delta T and Delta R were significantly higher for mid-shaft guides (p=0.0001,,p= 0.0001,hbox {and} p=0.001) compared to distal guides. The guide extension significantly improved the target registration and translational accuracy in all the volar radius locations (p=0.001). However, in the mid-shaft region, the guide extension yielded an increased total rotational error (p= 0.0001).ConclusionOur study demonstrates that positioning accuracy depends on the fitting location and on the guide design. In distal and proximal radial regions, the accuracy of guides with lateral extension is higher than standard guides and is therefore recommended for future use.

Three-dimensional surgical modelling with an open-source software protocol: study of precision and reproducibility in mandibular reconstruction with the fibula free flap

Very few surgical teams currently use totally independent and free solutions to perform three-dimensional (3D) surgical modelling for osseous free flaps in reconstructive surgery. This study assessed the precision and technical reproducibility of a 3D surgical modelling protocol using free open-source software in mandibular reconstruction with fibula free flaps and surgical guides. Precision was assessed through comparisons of the 3D surgical guide to the sterilized 3D-printed guide, determining accuracy to the millimetre level. Reproducibility was assessed in three surgical cases by volumetric comparison to the millimetre level. For the 3D surgical modelling, a difference of less than 0.1mm was observed. Almost no deformations (<0.2mm) were observed post-autoclave sterilization of the 3D-printed surgical guides. In the three surgical cases, the average precision of fibula free flap modelling was between 0.1mm and 0.4mm, and the average precision of the complete reconstructed mandible was less than 1mm. The open-source software protocol demonstrated high accuracy without complications. However, the precision of the surgical case depends on the surgeon’s 3D surgical modelling. Therefore, surgeons need training on the use of this protocol before applying it to surgical cases; this constitutes a limitation. Further studies should address the transfer of expertise.

Evaluation of Resins for Stereolithographic 3D-Printed Surgical Guides: The Response of L929 Cells and Human Gingival Fibroblasts.

Additive manufacturing is becoming increasingly important in dentistry for the production of surgical guides. The development of cost-effective desktop stereolithography (SLA) printing systems and the corresponding resins makes this novel technique accessible to dental offices and dental laboratories. The aim of the study was to reveal the response of soft tissue cells to Clear and Dental SG resins used in desktop SLA printing systems at different stages of processing. Cell activity of L929 cells and gingival fibroblasts (GF) in response to the materials was examined in indirect and direct monolayer culture models and a direct spheroid culture model based on MTT, resazurin-based toxicity assays, and live-dead staining. Overall we found that the impact of Clear and Dental SG resins on L929 and GF depends on the processing stage of the materials. Liquid Clear resin induced a stronger reduction of cell activity compared to Dental SG resin. Printing and postcuring reduced the impact on cell activity and viability. As in-house 3D printing for surgical guides is getting integrated in the digital workflow, our data suggest that careful adherence to processing guidelines—especially postcuring—is of clinical relevance.

Low-cost Design and Manufacturing of Surgical Guides for Mandibular Reconstruction Using a Fibula.

Background:Surgical cutting guides are used in mandibular reconstruction involving osteotomy of the mandible and fibula. Cutting guides produced using computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies have been reported recently. These guides aim to increase the benefits to patients by improving the accuracy, shortening the operating time, and correcting occlusion. However, the availability of these advanced technologies is limited in some regions of the world. To test whether we could produce low-cost surgical cutting guides, we made surgical guides and investigated their accuracy.Methods:Using free CAD software, we designed surgical cutting guides for the mandible and fibula and used these to perform virtual mandibular segmental osteotomies and fibula transplants in 12 model surgeries. The cutting guides were printed on a 3-dimensional (3D) printer. The model surgeries were performed using 3D mandibular models and cutting guides to check their accuracy. Deviations between the virtually simulated plan and the actual model surgery were investigated.Results:CAD and CAM technologies were used to design and 3D print the cutting guides and models. The guided surgeries were performed. The deviations were about 1.3 mm for mandibular osteotomy, less than 1 mm for fibular osteotomy, and within 2.4 mm for reconstructions of the mandible.Conclusions:Without using expensive software or products, we were able to design surgical cutting guides for the mandible and fibula and used these to perform virtual simulation of mandibular segmental osteotomy and fibular reconstruction. Model surgeries using 3D-printed surgical guides showed that the accuracy of reconstruction was within a 3-mm deviation. In circumstances where commercial CAD/CAM guides are not available, it may be possible to use CAD/CAM surgical guides in the clinic if doctors are willing to volunteer their time for the design and printing.