BACKGROUND: Long-term enophthalmos and diplopia resulting from orbital bone loss pose significant challenges in reconstructive surgery. This study evaluated the effectiveness of patient-specific porous titanium implants (PSIs) for addressing these conditions.
METHODS: This retrospective study involved 12 patients treated at Croix-Rousse Hospital, Lyon, from April 2015 to April 2022 who underwent late reconstruction via PSI for unilateral complex orbital bone loss. These implants were customized via 3D mirroring techniques on the basis of high-resolution computed tomography (CT) scans of the patients\' unaffected orbits.
RESULTS: All 12 patients presented with significant preoperative enophthalmos, with an average displacement of 3.24 mm, which was effectively corrected postoperatively to an average of 0.17 mm (p < 0.001). Orbital volume notably improved from a preoperative average of 3.38 mL to 0.37 mL postsurgery (p < 0.001). Functional improvements were evident as both enophthalmos and diplopia resolved completely. The Lancaster test revealed an improvement in the visual field, with 83.3 % of patients achieving normal results postoperatively.
CONCLUSIONS: By ensuring anatomical accuracy, patient-specific porous titanium implants, tailored from patient-specific imaging and fabricated via advanced 3D printing technology, provide a precise, effective, and reliable solution for reconstructing complex orbital defects and performing complicated revision surgeries.

Oral and maxillofacial surgery is a specialized surgical field devoted to diagnosing and managing conditions affecting the oral cavity, jaws, face and related structures. In recent years, the integration of 3D printing technology has revolutionized this field, offering a range of innovative surgical devices such as patient-specific implants, surgical guides, splints, bone models and regenerative scaffolds. In this comprehensive review, we primarily focus on examining the utility of 3D-printed surgical devices in the context of oral and maxillofacial surgery and evaluating their efficiency. Initially, we provide an insightful overview of commonly utilized 3D-printed surgical devices, discussing their innovations and clinical applications. Recognizing the pivotal role of materials, we give consideration to suitable biomaterials and printing technology of each device, while also introducing the emerging fields of regenerative scaffolds and bioprinting. Furthermore, we delve into the transformative impact of 3D-printed surgical devices within specific subdivisions of oral and maxillofacial surgery, placing particular emphasis on their rejuvenating effects in bone reconstruction, orthognathic surgery, temporomandibular joint treatment and other applications. Additionally, we elucidate how the integration of 3D printing technology has reshaped clinical workflows and influenced treatment outcomes in oral and maxillofacial surgery, providing updates on advancements in ensuring accuracy and cost-effectiveness in 3D printing-based procedures.

Dentigerous cysts, if left untreated, can grow significantly and weaken the mandible, posing risks of pathological or iatrogenic fracture. Treatment options may include decompression, marsupialization, and enucleation, which are available, with the choice being multifactorial and tailored to each case. This article describes the management of two complex dentigerous cysts at risk of fracture, one about an 84-year-old woman and the second about a 41-year-old man. The cysts and associated teeth were surgically removed, and simultaneously custom-made titanium osteosynthesis plates were placed to prevent per- and postoperative fracture risks. This approach appears to be indicated in cases where marsupialization or decompression is impossible and when there is a high risk of iatrogenic fracture.

UNASSIGNED: The primary objective of revision total knee surgery is to achieve solid bone fixation. Generally, this could be accomplished using sleeves and long stems, which require substantial remaining bone stock and may increase the risk of stem tip pain. An alternative approach involves the use of customized diaphyseal cones, which can preserve the integrity of the bone canal. This study evaluates the impact of employing femoral diaphyseal cones with various stem lengths on stress distribution and relative motion.
UNASSIGNED: CT scan data from five patients were used to generate the 3D model of the femur, cement, customized stems, and cones, along with assigning patient-specific material for each candidate\'s femur. Three different stem lengths, both with and without the customized cone, were assessed under three gait loading conditions to compare the resulting Von Mises stress distribution and relative motion.
UNASSIGNED: Analysis indicated that the use of customized femoral cones moderately increases stress distribution values up to 30 % while significantly reducing relative motion at the femoral canal-cone interface by nearly 60 %. The presence of the cone did not significantly alter relative motion with varying stem lengths, although stem length variation without a cone substantially affected these values.
UNASSIGNED: Incorporating cones alongside stems enhances metaphyseal fixation, reduces stress shielding, potentially allowing for the use of shorter stems. Furthermore, cones promote osseointegration by minimizing relative motion, ultimately improving prosthetic stability.

UNASSIGNED: Maxillary reconstruction is often a challenging task for the surgeons because of the complex anatomy. However, with the advances in virtual surgical planning (VSP) and 3D printing technology there is a new avenue for the surgeons which offers a suitable alternative to conventional flap-based reconstructions.
UNASSIGNED: In this article, we have described 4 case scenarios which were managed with the help of VSP and additive manufacturing technology for complex maxillary reconstruction procedures. Use of the technologies aided the clinician in achieving optimal outcomes with regards to form, function and esthetics.
UNASSIGNED: Virtual surgical planning (VSP) has gained a lot of impetus in past 1 decade. These aides the surgeon in determining the extent of disease and also carry out the treatment planning. In addition to VSP, the concept of additive manufacturing provides a viable alternative to the conventional reconstruction modalities for maxillary defect rehabilitation. Increased accuracy, rehabilitation of normal anatomical configuration, appropriate dental rehabilitation, decreased intra-operative time and post-operative complications are some of the advantages. In addition, patient-specific implants eliminate the need for a separate donor site. Apart from the treatment of pathologies, they also can be used for reconstruction of post-traumatic defect, where endosteal implant placement is not possible.
UNASSIGNED: These modalities show promising results for reconstruction of complex maxillary defects.

Reconstruction of craniomaxillofacial bone defects using 3D-printed hydroxyapatite (HA) bioceramic patient-specific implants (PSIs) is a new technique with great potential. This study aimed to investigate the advantages, disadvantages, and clinical outcomes of these implants in craniomaxillofacial surgeries. The PubMed and Embase databases were searched for patients with craniomaxillofacial bone defects treated with bioceramic PSIs. Clinical outcomes such as biocompatibility, biomechanical properties, and aesthetics were evaluated and compared to those of commonly used titanium or poly-ether-ether-ketone (PEEK) implants and autologous bone grafts. Two clinical cases are presented to illustrate the surgical procedure and clinical outcomes of HA bioceramic PSIs. Literature review showed better a biocompatibility of HA PSIs than titanium and PEEK. The initial biomechanical properties were inferior to those of autologous bone grafts, PEEK, and titanium but improved when integrated. Satisfactory aesthetic results were found in our two clinical cases with good stability and absence of bone resorption or infection. Radiological signs of osteogenesis were observed in the two clinical cases six months postoperatively. HA bioceramic PSIs have excellent biocompatible properties and imitate natural bone biomechanically and radiologically. They are a well-suited alternative for conventional biomaterials in the reconstruction of load-sharing bone defects in the craniomaxillofacial region.

Introduction: Bone tumors, characterized by diverse locations and shapes, often necessitate surgical excision followed by custom implant placement to facilitate targeted bone reconstruction. Leveraging additive manufacturing, patient-specific implants can be precisely tailored with complex geometries and desired stiffness, enhancing their suitability for bone ingrowth. Methods: In this work, a finite element model is employed to assess patient-specific lattice implants in femur bones. Our model is validated using experimental data obtained from an animal study (n = 9). Results: The results demonstrate the accuracy of the proposed finite element model in predicting the implant mechanical behavior. The model was used to investigate the influence of reducing the elastic modulus of a solid Ti6Al4V implant by tenfold, revealing that such a reduction had no significant impact on bone behavior under maximum compression and torsion loading. This finding suggests a potential avenue for reducing the endoprosthesis modulus without compromising bone integrity. Discussion: Our research suggests that employing fully lattice implants not only facilitates bone ingrowth but also has the potential to reduce overall implant stiffness. This reduction is crucial in preventing significant bone remodeling associated with stress shielding, a challenge often associated with the high stiffness of fully solid implants. The study highlights the mechanical benefits of utilizing lattice structures in implant design for enhanced patient outcomes.

BACKGROUND: Temporomandibular joint (TMJ) replacement may be indicated for various pathological conditions, and the type of condition can affect the surgical procedure and outcomes. The causes of limited range of motion after alloplastic TMJ replacement have not been extensively studied.
OBJECTIVE: The present study aimed to evaluate the impact of preoperative jaw anatomy and functional status on the immediate and long-term outcomes of total TMJ replacement using a two-component patient-specific TMJ endoprosthesis.
METHODS: This retrospective study included 31 patients who underwent total TMJ replacement surgery between 2016 and 2020. The main outcome variable was the maximal incisal opening (MIO) after treatment. Secondary outcome variables included MIO improvement and the presence and type of postoperative complications. The primary predictive variable was the preoperative initial MIO. Secondary predictive variables included sex, age, indications for TMJ replacement, preoperative occlusion, condition of the glenoid fossa and/or condyle, shortening of the mandibular ramus, sagittal mandible position, lateral chin deviation, shape of the coronoid process, and type of surgery.
RESULTS: The mean preoperative MIO was 13.0 ±8.0 mm, while the mean MIO 1 month after surgery was 20.6 ±5.5 mm, which was not statistically significant. However, at a later follow-up, functional parameters showed a significant improvement (p = 0.003), with a mean MIO of 32.5 ±5.0 mm 3 years after surgery. Statistical analysis indicated that the initial mouth opening is the strongest predictor of long-term functional recovery after TMJ replacement. Postoperative complications occurred in 4 cases (12.9%) following patient-specific endoprosthesis (PSE) placement.
CONCLUSIONS: The use of PSEs for TMJ replacement has enabled the restoration of anatomical relationships in complex clinical cases and an improvement in mouth opening. The preoperative MIO was the only factor that significantly influenced long-term functional outcomes.

UNASSIGNED: Surgeons still face difficulties when performing aseptic acetabular revision on patients with extensive defects. Advances in three-dimensional printing technology (3DP) have afforded to the surgeons to create a patient-specific implant matching the morphology and topography of the defect.
UNASSIGNED: The aim of the current research was to determine the survivorship in the treatment of acetabular bone defects with pelvic discontinuity (PD).
UNASSIGNED: In order to reconstruct Paprosky type III defects with PD, twenty-three patients underwent revision total hip arthroplasty (THA) utilizing 3D-printed implants (Mobelife). The primary outcomes were the implant-associated failure rate correlated with survivorship. As secondary variables, complications and the effect of age, sex, comorbidities, history of infections and the presence of other lower limb arthroplasties on a new revision were analyzed.
UNASSIGNED: Patients were followed out to a mean of 67.22 ± 39.44 months (range, 0.9-127 months). Mobelife implant mean survival was 102.57 ± 9.90 months (95% CI 83.17-121.96). The cohort\'s implant one-year survival rate was 87%; at ten years, it dropped to 78.3%. There were four revisions: three due to periprosthetic joint infection (PJI) and one case due to aseptic loosening. Cox regression analysis did not identify any variable as predictor of failure.
UNASSIGNED: The use of 3DP patient-specific acetabular components has shown encouraging results and it is a viable treatment option for addressing acetabular defects with combined PD in aseptic THA revision.

Sarcomas of the extremities are rare entities, the treatment of which requires special expertise. Even if the treatment of patients is always interdisciplinary, the surgical R0 resection is the key point of each curatively intended treatment. In addition to resection in sano, the aim is to preserve the extremities and function, so that defect reconstruction after resection plays a decisive role. Due to the heterogeneity of tumors as well as their localization and extent, reconstruction is always an individually adapted treatment. Modular tumor endoprostheses are often used in this context, which can be constructed according to the size of the defect. The transplantation of autologous or allogeneic bone is also frequently used alone or as an additive procedure. Patient-specific (mega)prostheses are used particularly for pelvic tumors. Defect reconstruction using scaffold-based procedures from the field of tissue engineering is being tested as a promising procedure for the future. This article provides an overview of the treatment principles for sarcomas of the extremities and their individual reconstruction options.
UNASSIGNED: Sarkome der Extremitäten sind seltene Entitäten, deren Therapie einer besonderen Expertise bedarf. Auch wenn die Behandlung der Patienten stets interdisziplinär erfolgt, ist die chirurgische R0-Resektion der Grundstein der kurativ intendierten Therapie. Ziel ist dabei neben der Resektion im Gesunden der Extremitäten- und Funktionserhalt, sodass der Defektrekonstruktion nach Resektion eine entscheidende Rolle zukommt. Aufgrund der Heterogenität der Tumoren sowie deren Lokalisation und Ausdehnung ist die Rekonstruktion immer eine individuell angepasste Therapie. Häufig finden hierbei modulare Tumorendoprothesen Anwendung, die entsprechend der Defektgröße aufgebaut werden können. Als alleiniges oder additives Verfahren ist zudem die Transplantation autologen oder allogenen Knochens häufig. Insbesondere bei Tumorbefall des Beckens kommen patientenspezifisch angefertigte (Mega‑)Prothesen zum Einsatz. Als zukunftsträchtiges Verfahren wird die Defektrekonstruktion über gerüstträgerbasierte Verfahren aus dem Bereich des Tissue-Engineerings erprobt. Der vorliegende Artikel bietet eine Übersicht über die Therapieprinzipien bei Sarkomen der Extremitäten und den individuellen Rekonstruktionsmöglichkeiten.