Patient-specific Surgical Guides Research Articles

"Intercalary Allograft Reconstruction using 3D Designed, Patient-Specific Surgical Guides and Plate during Resection of Primary Malignant Bone Tumors: Workflow and Surgical Technique"

"Intercalary Allograft Reconstruction using 3D Designed, Patient-Specific Surgical Guides and Plate during Resection of Primary Malignant Bone Tumors: Workflow and Surgical Technique"

Modified patient-specific surgical-guide-assisted precise treatment of unilateral comminuted zygomaticomaxillary complex fractures: A 5-year retrospective study

Our study aimed to evaluate modified patient-specific surgical-guide-assisted precise treatment of unilateral comminuted zygomaticomaxillary complex (ZMC) fractures.The retrospective non-randomized study was conducted in a single hospital in China. All patients diagnosed with unilateral comminuted ZMC fractures between January 1, 2018 and December 31, 2022 were retrospectively reviewed. All patients underwent preoperative spiral computed tomography (CT). CT data were processed using software to DICOM format and transferred to Proplan CMF3.0 for preoperative virtual surgical planning and postoperative evaluation. All data were extracted from standardized electronic medical records. All statistical analyses were performed using SPSS version 20.0. The chi-square test and t-test were used for statistical analyses.The 54 included patients were divided into two comparable, equal cohorts of 27 patients, and followed up for at least 6 months. Fracture reduction was assisted using the modified patient-specific surgical guides in the guide group (23 males, four females; mean age 37.74 ± 12.07 years) and without the modified patient-specific surgical guides in the control group (20 males, seven females; mean age 37.44 ± 13.58 years).In the guide group, the mean eminence deviation between the affected and unaffected sides was 1.01 ± 0.92 mm, and the mean width deviation between the affected and unaffected sides was 1.29 ± 1.32 mm. In the control group, the mean eminence deviation between the affected and unaffected sides was 1.99 ± 1.69 mm, and the mean width deviation between the affected and unaffected sides was 2.68 ± 2.01 mm. The differences in facial protrusion (p = 0.001) and width (p = 0.003) symmetry between the affected and healthy sides of the two groups were statistically significant (p < 0.05).In conclusion, applying the modified patient-specific surgical guides to unilateral comminuted zygomaticomaxillary complex fracture reduction has the advantages of greater predictability and effectiveness, and improved bilateral ZMC symmetry. It should be noted that this approach would be especially beneficial for less-experienced surgeons.

Remodelling surgery with 3D printed patient specific surgical guides in patients with chronic diffuse sclerosing osteomyelitis/tendoperiostitis of the mandible, a case series.

Patients with chronic diffuse sclerosing osteomyelitis/tendoperiostitis (DSO/TP) of the mandible may complain about facial asymmetry as a result of mandibular deformity, one of the characteristics of DSO/TP of the mandible. If the disease is fully extinguished, remodelling surgery could be performed to treat complaints of facial asymmetry. This study reports the results of remodelling surgery with three-dimensional (3D) designed- and -printed patient-specific surgical guides. 3D printed guides were designed and manufactured by using mirroring of the contralateral non-affected mandible. Subsequently, the surgical procedure was performed under general anaesthesia using these surgical guides. Four patients (all female) aged 15 (±2.8) years were included. They all complained about facial asymmetry and were planned for surgery with patient-specific surgical guides. Three of those surgeries were performed, of which two patients were satisfied with the result and the other patient is planned for re-surgery because of persistent aesthetical complaints. The last patient cancelled her surgery, because she eventually accepted her asymmetry with the help of a psychologist. The use of patient-specific surgical guides in remodelling surgery of the mandible could enable a more predictable and symmetrical outcome, which could minimise the chance for re-surgery and could increase patient satisfaction. Furthermore, it could minimise the chance of iatrogenic damage to the inferior alveolar nerve.

A quantitative comparison of bone resection margin distances in virtual surgical planning versus histopathology: a prospective study.

Positive bone margins have been shown to be associated with worse locoregional control and survival performance in oral oncology patients. With the application of computer-assisted surgery and patient-specific surgical guides, the authors can accurately execute the preoperative osteotomy plan. However, how well the authors can predict the margin distance in the final histopathology with a preoperative computed tomography (CT) scan, the factors associated with it, and how much leeway CT should spare when designing the osteotomy planes during virtual surgical planning (VSP) remain to be investigated. Patients from January 2021 to December 2022 with benign or malignant jaw tumors and with signs of bone marrow involvement in the preoperative CT scan in our center were prospectively recruited to the study. VSP and measurement of the closest margin distance in the CT scan were performed by the single team of surgeons. The resection specimen was processed, and the margin distances were measured by a dedicated senior pathologist with the knowledge of orientation of the osteotomy planes. A total of 35 patients were recruited, with 21 malignant and 14 benign cases. Sixty-eight bone margins were quantitatively analyzed. No significant difference in margin distances measured from the CT scan and final histopathology was detected ( P =0.19), and there was a strong correlation between the two (r s =0.74, P <0.01). A considerable amount of variance was detected in the level of discrepancy between margin distances measured in the CT scan and final histopathology (overall SD=6.26 mm, malignancy SD=7.44 mm, benign SD=4.40 mm). No significant correlation existed between the two margin distances when only maxilla tumor margins were assessed ( P =0.16). The bone margin distance in VSP is reliably correlated to the final pathological margin distance. A leeway distance of 15mm and 9mm should be considered when designing the osteotomy planes for malignancy and benign cases, respectively. Extra attention should be paid to maxilla cases when predetermining the osteotomy planes during VSP.

High Volume 3D Printer and Developed of High-Volume Extruders for Gelatin and Liquids

Over the last decade, the development of 3D printing technology has led to both increased interest and availability of these machines. The steady growth and demand have made 3D printing an affordable and consumer-friendly craft. Due to the shrinking barrier-of-entry, the technology is increasingly integrated into wider areas of science and research, as well as the manufacturing industry in general. The demand for individualized medical solutions is continuously expanding in multiple fields, such as medical training and patient-specific surgical guides—exposing a need for further development of these technologies for mainstream applications. The research areas of material science, life science, biotechnology, and medical applications have greatly benefited from the increasing availability of this technology—especially in regard to 3D printing high viscosity substrates which are biological, biocompatible, or bioresorbable. In this area of research and development, mainly micro-extrusion syringe-based systems are used. However, these extruders are limited to the volume of the utilized syringe. The presented work primary objective was to develop a multi-material 3D printer capable of processing substrates with a wide variety of viscosities, with a particular focus on biological-based substrates. The entire project was developed with an open-source mindset—with the intent of furthering future research possibilities within this space. A coreXY printer (0.5x0.5x0.5 m) was developed, including an automatic tool changing mechanism. A peristaltic pump and ink jet extruder were developed and manufactured to improve their processability for additive manufacturing and extrusion of hydrogels and as well as liquids.

PATIENT-SPECIFIC DISTAL FEMORAL OSTEOTOMY REDUCES SURGICAL TIME: DEMONSTRATION OF A NOVEL PATIENT-SPECIFIC TECHNIQUE

AbstractBackgroundDistal femoral osteotomy is an established successful procedure which can delay the progression of arthritis and the need for knee arthroplasty. The surgery, however, is complex and lengthy and consequently it is generally the preserve of highly experienced specialists and thus not widely offered. Patient specific instrumentation is known to reduce procedural complexity, time, and surgeons’ anxiety levels1 in proximal tibial osteotomy procedures. This study evaluated a novel patient specific distal femoral osteotomy procedure (Orthoscape, Bath, UK) which aimed to use custom-made implants and instrumentation to provide a precision correction while also simplifying the procedure so that more surgeons would be comfortable offering the procedure.Presenting problemThree patients (n=3) with early-stage knee arthritis presented with valgus malalignment, the source of which was predominantly located within the distal femur, rather than intraarticular. Using conventional techniques and instrumentation, distal femoral knee osteotomy cases typically require 1.5–2 hours surgery time. The use of bi-planar osteotomy cuts have been shown to improve intraoperative stability as well as bone healing times2. This normally also increases surgical complexity; however, multiple cutting slots can be easily incorporated into patient specific instrumentation.Clinical managementAll three cases were treated at a high-volume tertiary referral centre (Istituto Ortopedico Rizzoli, Bologna) using medial closing wedge distal femoral knee osteotomies by a team experienced in using patient specific osteotomy systems3. Virtual surgical planning was conducted using CT-scans and long-leg weight-bearing x-rays (Orthoscape, Bath, UK). Patient specific surgical guides and custom-made locking plates were design for each case. The guides were designed to allow temporary positioning, drilling and bi-planar saw-cutting. The drills were positioned such that the drills above and below the osteotomy became parallel on closing following osteotomy wedge removal. This gave reassurance of the achieved correction allowed the plate to be located precisely over the drills. All screw lengths were pre-measured.DiscussionThe surgical time reduced to approximately 30 minutes by the third procedure. It was evident that surgical time was saved because no intraoperative screw length measurements were required, relatively few x-rays were used to confirm the position of the surgical guide, and the use of custom instrumentation significantly reduced the surgical inventory. The reduced invasiveness and ease of surgery may contribute to faster patient recovery compared to conventional techniques. The final post-operative alignment was within 1° of the planned alignment in all cases.Declaration of Interest(a) fully declare any financial or other potential conflict of interest

3D-printed patient specific surgical guides: Balancing accuracy with practicality

IntroductionThree-dimensional (3D) printing technology has been used in orthopaedic surgery in recent years to manufacture customized surgical cutting jigs. However, there is scarcity of literature and information regarding the optimal parameters of an ideal jig. Our study aims to determine the optimum parameters to design surgical jigs that can produce accurate cuts, and remain practical for use, to serve as a guide for jig creation in future. Methods and materialsA biomechanical lab study was designed to investigate whether the thickness of a jig and the height of its cutting slot can significantly affect cutting accuracy. Surgical jigs were 3D printed in medical grade, and an oscillating sawblade was used to mimic intraoperative surgical cuts through the cutting slots onto wooden blocks, which were then analysed to determine the accuracy of cuts. ResultsStatistical analysis was performed on a total of 72 cuts. The cutting accuracy increased when the thickness of the jig increased, at all slot heights. The cutting accuracy also increased as the slot height decreased, at all jig thicknesses. Overall, the parameters for jig construction that yielded the most accurate cuts were a jig thickness of 15 mm, in combination with a slot height of 100 % of the width of the sawblade. Additionally, at a jig thickness of 15 mm, there was no statistically significant difference in cutting accuracy when increasing the slot height to 120 %. ConclusionThis study is the first to propose tangible parameters that can be applied to surgical jig construction to obtain reproducible accurate cuts. Provided that a jig of 15 mm thickness can be accommodated by the size of the wound, the ideal surgical jig with a superior balance of accuracy and useability is 15 mm thick, with a cutting slot height of 120 % of the sawblade thickness.

Patient-specific plates for facial fracture surgery: A retrospective case series

ObjectivesSurgeons often encounter challenges when treating maxillofacial fractures using conventional methods that involve trimming or bending ready-made titanium plates for open reduction and internal fixation (ORIF) since it can be time-consuming, imprecise, and inconvenient. This retrospective case series aimed to introduce a novel bone reduction method that utilizes virtual planning, patient-specific surgical guides, and titanium plates. MethodsSeven patients with mandibular symphysis or subcondylar fractures resulting from facial trauma underwent cone-beam computed tomography (CBCT) or facial CT scans, and their medical histories were documented. Virtual surgery was conducted based on three-dimensional (3D) stereolithography images derived from CT scans using the FaceGide software (MegaGen, Daegu, Korea). ORIF was performed using patient-specific surgical guides and plates that were designed, printed, and milled. Radiographic, clinical, and occlusal evaluations were conducted at two weeks and six weeks postoperatively. Subsequently, 3D images from virtual surgery and postoperative CT scans were compared. ResultsThe comparison of 3D virtual surgery and postoperative images revealed minimal surface differences of less than 1 mm. T-scan evaluations indicated that there were no statistically significant differences between the two- and six-week postoperative assessments. Favorable clinical outcomes were observed. ConclusionThis novel method demonstrated stable outcomes in terms of occlusion and healing, with no notable complications. Consequently, this approach may serve as a viable alternative to conventional methods. Clinical SignificanceFacial fracture surgery that utilizes patient-specific surgical guides and plates within a digital workflow can facilitate meticulous surgical planning, reducing the risk of complications and minimizing operation time.

Proximal humerus fracture sequelae: are corrective osteotomies still a taboo? The role of three-dimensional preoperative planning and patient-specific surgical guides for proximal humerus corrective osteotomy in combination with reverse shoulder arthroplasty.

Symptomatic proximal humeral fracture sequelae (PHFS) represent a surgical challenge due to the altered bone and soft tissue morphology. The purpose of this study was to report the outcome of Multiplanar Corrective Humeral Osteotomies (MCHOs) in combination with reverse total shoulder arthroplasty (rTSA) performed following a three-dimensional (3D) preoperative planning and using a 3D-printed patient-specific surgical instrumentation (PSI) in type 1C, 1D, and 4 PHFS. In this prospective monocentric study, we enrolled patients affected by symptomatic PHFS type 1C, 1D, or 4 of Boileau's classification, treated between 2018 and 2019 with rTSA associated to MCHO and followed-up at 12 and 24 mo. The preoperative and postoperative Constant Score (CS), visual analog scale, and Disabilities of the Arm, Shoulder and Hand (DASH) score were recorded. All patients underwent a preoperative computed tomography, then a dedicated software was used to run a segmentation algorithm on computed tomography images. Metaphyseal bone cuts were virtually performed before surgery in all patients, and a 3D-printed PSI was used to reproduce the planned osteotomies invivo. Twenty patients completed a 2-y follow-up. The mean (± standard deviation) CS, visual analog scale, and DASH values improve from 24.3 (± 8.8), 6.5 (± 1.3), 60.7 (± 9.6) preoperatively, to 67.7 (± 11.4), 1.6 (± 0.8), 24.1 (± 13.1) points after surgery, respectively. The minimally clinical important difference for CS and DASH score was achieved in 95% of patients. No major complication was observed. One patient showed an unexplained worsening of clinical scores between the 12 and the 24-mo follow-up, while in one patient bone resorption of the greater tuberosity was observed on radiographs at 2 y, with no clinical impact. The combination of preoperative 3D planning and intraoperative use of 3D-printed PSI to perform MCHO as concurrent procedure in the context of rTSA in the treatment of Boileau type 1C, 1D, and 4 PHFS may lead to a satisfactory clinical outcome at 2 y of follow-up.

Accuracy of self-designed 3D-printed patient-specific surgical guides and fixation plates for advancement genioplasty.

A prospective study was conducted to evaluate the accuracy and complications of 3D-printed patient-specific surgical guides and plates that were designed and finished in-house. Eighteen patients who required advancement genioplasty, with or without concomitant orthognathic surgery, were enrolled in the study. Virtual surgical movements were simulated using the patient's CBCT scans, and the computer-aided designing of patient-specific surgical guides and fixation plates was performed in the authors' department. CBCT scans were taken at 1-month postoperatively, and stereolithographic models of the preoperative virtual plan and the postoperative CBCT scan were registered. Part comparisons were performed to assess the accuracy of the movements. The median, minimum, and maximum differences were measured. Two landmarks, the Menton (Me) and Pogonion (Pog), were also used to compare the differences locally. The median deviation for the 18 cases was 0.19 mm. The median deviation at the Me and Pog were 0.67 and 0.41 mm, respectively. There was no significant correlation between the surgical movement of < 7 mm advancement and the transfer accuracy (P = 0.77). No adverse events or complications were reported within the postoperative 6-month period. The protocol of self-designed 3D-printed patient-specific surgical guides and plates provided an accurate method to transfer the virtual surgical plan to the operating theater. (Int J Comput Dent 2022;25(4):369-0; doi: 10.3290/j.ijcd.b2599791).

Personalised 3D Printed high tibial osteotomy achieves a high level of accuracy: 'IDEAL' preclinical stage evaluation of a novel patient specific system.

High tibial osteotomy (HTO) is an effective surgical treatment for isolated medial compartment knee osteoarthritis; however, widespread adoption is limited due to difficulty in achieving the planned correction, and patient dissatisfaction due to soft tissue irritation. The aim of this study was to assess the accuracy of a novel HTO system with 3D printed patient specific implants and surgical guides using cadaveric specimens. Local ethics committee approval was obtained. The novel opening wedge HTO procedure was performed on eight cadaver leg specimens. Whole lower limb CT scans pre- and post-operatively provided geometrical assessment quantifying the discrepancy between pre-planned and post-operative measurements for key variables: the gap opening angle and the patient specific surgical instrumentation positioning. The average discrepancy between the pre-operative plan and the post-operative osteotomy correction angle was: 0.0 ± 0.2° The R² value for the regression correlation was 0.95. The average error in implant positioning was -0.4 ± 4.3 mm, -2.6 ± 3.4 mm and 3.1 ± 1.7° vertically, horizontally, and rotationally respectively. This novel HTO surgery has greater accuracy in correction angle achieved compared to that reported for conventional or other patient specific methods with published data available. This system could potentially improve the accuracy of osteotomy correction angles achieved surgically.

Statistical shape modelling of the thoracic spine for the development of pedicle screw insertion guides

Spinal fixation and fusion are surgical procedures undertaken to restore stability in the spine and restrict painful or degenerative motion. Malpositioning of pedicle screws during these procedures can result in major neurological and vascular damage. Patient-specific surgical guides offer clear benefits, reducing malposition rates by up to 25%. However, they suffer from long lead times and the manufacturing process is dependent on third-party specialists. The development of a standard set of surgical guides may eliminate the issues with the manufacturing process. To evaluate the feasibility of this option, a statistical shape model (SSM) was created and used to analyse the morphological variations of the T4–T6 vertebrae in a population of 90 specimens from the Visible Korean Human dataset (50 females and 40 males). The first three principal components, representing 39.7% of the variance within the population, were analysed. The model showed high variability in the transverse process (~ 4 mm) and spinous process (~ 4 mm) and relatively low variation (< 1 mm) in the vertebral lamina. For a Korean population, a standardised set of surgical guides would likely need to align with the lamina where the variance in the population is lower. It is recommended that this standard set of surgical guides should accommodate pedicle screw diameters of 3.5–6 mm and transverse pedicle screw angles of 3.5°–12.4°.

Cochlear implant positioning and fixation using 3D-printed patient specific surgical guides; a cadaveric study.

To develop and validate the optimal design and evaluate accuracy of individualized 3D- printed surgical guides for cochlear implantation. Positioning and fixation of the cochlear implant (CI) are commonly performed free hand. Applications of 3-dimensional (3D) technology now allow us to make patient specific, bone supported surgical guides, to aid CI surgeons with precise placement and drilling out the bony well which accommodates the receiver/stimulator device of the CI. Cone beam CT (CBCT) scans were acquired from temporal bones in 9 cadaveric heads (18 ears), followed by virtual planning of the CI position. Surgical, bone-supported drilling guides were designed to conduct a minimally invasive procedure and were 3D-printed. Fixation screws were used to keep the guide in place in predetermined bone areas. Specimens were implanted with 3 different CI models. After implantation, CBCT scans of the implanted specimens were performed. Accuracy of CI placement was assessed by comparing the 3D models of the planned and implanted CI's by calculating the translational and rotational deviations. Median translational deviations of placement in the X- and Y-axis were within the predetermined clinically relevant deviation range (< 3 mm per axis); median translational deviation in the Z-axis was 3.41 mm. Median rotational deviations of placement for X-, Y- and Z-rotation were 5.50°, 4.58° and 3.71°, respectively. This study resulted in the first 3D-printed, patient- and CI- model specific surgical guide for positioning during cochlear implantation. The next step for the development and evaluation of this surgical guide will be to evaluate the method in clinical practice.

HoloLens 1 vs. HoloLens 2: Improvements in the New Model for Orthopedic Oncological Interventions.

This work analyzed the use of Microsoft HoloLens 2 in orthopedic oncological surgeries and compares it to its predecessor (Microsoft HoloLens 1). Specifically, we developed two equivalent applications, one for each device, and evaluated the augmented reality (AR) projection accuracy in an experimental scenario using phantoms based on two patients. We achieved automatic registration between virtual and real worlds using patient-specific surgical guides on each phantom. They contained a small adaptor for a 3D-printed AR marker, the characteristic patterns of which were easily recognized using both Microsoft HoloLens devices. The newest model improved the AR projection accuracy by almost 25%, and both of them yielded an RMSE below 3 mm. After ascertaining the enhancement of the second model in this aspect, we went a step further with Microsoft HoloLens 2 and tested it during the surgical intervention of one of the patients. During this experience, we collected the surgeons’ feedback in terms of comfortability, usability, and ergonomics. Our goal was to estimate whether the improved technical features of the newest model facilitate its implementation in actual surgical scenarios. All of the results point to Microsoft HoloLens 2 being better in all the aspects affecting surgical interventions and support its use in future experiences.

Custom made cutting guides and osteosynthesis plates versus CAD/CAM occlusal splints in positioning and fixation of the maxilla in orthognathic surgery: A prospective randomized study

The aim of this study is to compare the accuracy of maxilla positioning in orthognathic surgery with the use of custom-made devices (cutting guides and patient-fitted osteosynthesis plates) comparing to CAD/CAM splints.A prospective randomized study was performed. Patients with dentofacial deformities undergoing orthognathic surgery were compared, using customized guides (experimental group) vs. CAD/CAM surgical splints (control group) for the repositioning of the upper maxilla. Preoperative and postoperative CT scans were used to compare positioning and fixation of the maxilla in the three planes of space.A total of 30 patients were included in the study (15 patients in each study group). The mean error obtained with customized guides was 0.8 mm (range 0.1–1.9) in the anterior-posterior axis, 0.4 mm (range 0–1.4) in the vertical axis and 0.2 mm (range 0–1.1) in the horizontal axis. There were statistically significant differences in the anterior-posterior and vertical axes in favour of the customized implants, whereas there were no differences in the horizontal plane. Furthermore, there was a mean reduction of the operative time of 36.5 min in the experimental group.Within the limitations of the study it seems that patient specific surgical guides should be preferred when accuracy of repositioning of the maxilla and saving operative time are the priority.

Intra-articular opening wedge osteotomy for varus ankle arthritis with computer-assisted planning and patient-specific surgical guides: a retrospective case series

BackgroundComputer-assisted preoperative planning, combined with PSI has become an effective technique for treating complex limb deformities. The purpose of this study was to evaluate the efficacy and safety of the novel technique in corrective osteotomy for intra-articular varus ankle deformities associated with osteoarthritis and ankle instability.MethodsNineteen patients with intra-articular varus ankle arthritis were reviewed between April 2017 and June 2019, including ten men and nine women with a mean age of 58.3 ± 9.9 years (range, 38 to 76 years). All patients underwent intra-articular opening wedge osteotomy assisted by 3D virtual planning and PSI. Weight-bearing radiographs were used to assess the radiographic results, including TAS angle, TT angle, TMM angle, TC angle, TLS angle, opening-wedge angle, and wedge height. Functional outcomes were assessed by the AOFAS score, VAS score, and ROM of the ankle.ResultsThe average follow-up time was 32.2 ± 9.0 months (range, 22 to 47 months). The average union time was 4.4 ± 0.9 months (range, 3.0 to 6.5 months). The TAS angle significantly changed from 84.1 ± 4.6° preoperatively to 87.7 ± 3.1° at the 1-year follow-up and 86.2 ± 2.6° at the latest follow-up. Similarly, the TT angle, TMM angle and TC angle changed significantly at the 1-year follow-up compared with the preoperative assessment and remained stable until the last follow-up. However, the TLS was not corrected significantly. The postoperative obtained opening-wedge angle, and wedge height showed no significant change with preoperative planning. The overall complication rate was 15.8%. The mean VAS score improved from 5.3 ± 0.6 to 2.7 ± 0.7. The mean AOFAS score improved from 56.2 ± 7.6 to 80.6 ± 4.6. However, the ROM showed no significant change.ConclusionsAccurate correction and satisfactory functional recovery were attained with computer-assisted planning and PSI in the corrective osteotomy of intra-articular varus ankle deformities.

EPPOCRATIS: Expedited Preoperative Point-of-Care Reduction of Fractures to Normalized Anatomy and Three-Dimensional Printing to Improve Surgical Outcomes.

Virtual surgical planning and three-dimensional printing have been invaluable tools in craniomaxillofacial surgery. From planning head and neck reconstruction to orthognathic surgery and secondary reconstruction of maxillofacial trauma, virtual surgical planning and three-dimensional printing allow the surgeon to rehearse the surgical plan and use patient-specific surgical guides for carrying out the plan accurately. However, the process of virtual surgical planning and three-dimensional printing requires time and coordination between the surgeon on one hand and the biomedical engineers and designers on the other hand. Outsourcing to third-party companies contributes to inefficiencies in this process. Advances in surgical planning software and three-dimensional printing technology have enabled the integration of virtual surgical planning and three-dimensional printing at the treating hospital, the point of care. This allows for expedited use of this process in semiurgent surgical cases and acute facial trauma cases by bringing the surgeon, radiologist, biomedical engineers, and designers to the point of care. In this article, the authors present the utility of EPPOCRATIS, expedited preoperative point of care reduction of fractures to normalized anatomy and three-dimensional printing to improve surgical outcomes, in the management of acute facial trauma.

Computer aided surgery planning and patient specific surgical guides

Computer aided surgery planning and patient specific surgical guides

Use of 3D Planning and Patient-specific Guides for Proximal Humerus Corrective Osteotomy Associated With Shoulder Prosthesis Implantation in Proximal Humeral Varus Malunion.

Humeral stem prosthesis implantation in case of proximal humerus varus malunion (type 1D fracture sequelae) is often complicated by greater tuberosity fracture and by posterosuperior rotator cuff iatrogenic damage. Moreover, the varus malunited humeral head could lead to scapular impingement and reduce the range of motion. To address this problem, we introduced a new surgical procedure consisting in a proximal humerus osteotomy, planned with three-dimensional (3D) preoperative virtual surgery, and performed with patient-specific surgical guides, to correct humerus deformity before the implantation of the prosthetic humeral stem. A 3D evaluation of the deformity, based on the comparison to the healthy contralateral side or to anatomical standard values, is firstly performed. The metaphyseal osteotomy is then planned and virtually performed. To faithfully reproduce the planned correction, 3D printed surgical guides are prepared. Before the surgery, it is advisable to perform a simulation of the planned osteotomies to verify their real feasibility and to find any critical issues. Preliminary outcomes of this surgical technique are encouraging, but formal studies are warranted to validate its clinical utility and longevity of results.

G-ear: a user-friendly tool for assisted autologous ear reconstruction.

The major breakthroughs in the fields of reverse engineering and additive manufacturing have dramatically changed medical practice in recent years, pushing for a modern clinical model in which each patient is considered unique. Among the wide spectrum of medical applications, reconstructive surgery is experiencing the most benefits from this new paradigm. In this scenario, the present paper focuses on the design and development of a tool able to support the surgeon in the reconstruction of the external ear in case of malformation or total absence of the anatomy. In particular, the paper describes an appositely devised software tool, named G-ear, which enables the semi-automatic modeling of intraoperative devices to guide the physician through ear reconstruction surgery. The devised system includes 3D image segmentation, semi-automated CAD modelling and 3D printing to manufacture a set of patient-specific surgical guides for ear reconstruction. Usability tests were carried out among the surgeons of the Meyer Children's Hospital to obtain an assessment of the software by the end user. The devised system proved to be fast and efficient in retrieving the optimal 3D geometry of the surgical guides and, at the same time, to be easy to use and intuitive, thus achieving high degrees of likability.