Navigation-assisted maxillofacial reconstruction: accuracy and predictability

Mandibular Reconstruction Modalities Using Virtual Surgical Planning and 3D Printing Technology: A Tertiary Care Centre Experience

Introduction

Mandibular reconstruction is often challenging. However, the revolution of computer-assisted design and computer-assisted manufacturing (CAD/CAM), virtual surgical planning (VSP) and 3D printing technology have changed this notion.

Patients and Methods

In this article, we have described six case scenarios where various aspects of VSP and 3D printing technology have been utilized for complex mandibular reconstruction procedures, to provide the patients with the best possible outcome in terms of form, function, and aesthetics.

Discussion

Virtual planning for tumour resection and fibula osteotomies and 3D printing of cutting guides and stereolith models have changed the face of mandibular reconstruction techniques. 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. 3D printed titanium cribs or meshes not only provide robustness, but also incorporates additional features that enable bone graft placement and excellent dental rehabilitation.

Conclusion

These modalities show promising results for reconstruction of complex mandibular defects.

Application of dynamic navigation technology in oral and maxillofacial surgery

OBJECTIVES

Dynamic navigation (DN) technology has ushered in a paradigm shift in dentistry, revolutionizing the precision of diverse procedures in oral and craniofacial surgery. This comprehensive review aims to review the manifold applications of DN, including implantology, endodontics, oral and dental surgeries, and other dental disciplines.

MATERIALS AND METHODS

A thorough search of the online databases PubMed and Google Scholar was conducted up to March 2024. Publications associated with DN in the field of oral and maxillofacial surgery were sourced.

RESULTS

Narrative literature review.

CONCLUSIONS

DN harnesses cone beam computerized tomography imaging, virtual design software, and motion tracking technology to construct a virtual model of the patient's oral cavity, affording real-time instrument tracking during procedures. Notably, in implantology, DN facilitates implant placement, enhances safety measures, and augments procedural efficiency. The application of DN in sinus lift procedures contributes to improved surgical outcomes and reduced complications. Within endodontics, DN guides root canal treatment (RCT), retreatment of failed RCT, and endodontic microsurgery, ensuring conservative access cavities and precise canal location. Beyond these, the versatility of DN extends to encompass maxillomandibular and orthognathic surgeries, tooth extraction, removal of foreign bodies, and facial reconstruction. However, it is crucial to acknowledge potential disadvantages and error-prone scenarios as DN technologies advance.

CLINICAL SIGNIFICANCE

DN technology empowers dentists with high accuracy, heightened safety protocols, and increased procedural efficiency, culminating in enhanced patient outcomes across various dental procedures. As DN technology further expands, its pivotal role will advance in the future of oral and maxillofacial surgery.

The Potential of Oncolytic Virotherapy in the Treatment of Head and Neck Cancer: A Comprehensive Review

Head and neck cancer (HNC) represents a challenging oncological entity with significant morbidity and mortality rates. Despite advances in conventional therapies, including surgery, chemotherapy, and radiation therapy, the overall survival rates for advanced HNC remain suboptimal. In recent years, the emerging field of oncolytic virotherapy has gained attention as a promising therapeutic approach for various malignancies, including HNC. This review provides a comprehensive overview of the current understanding of oncolytic viruses (Ovs) in the context of HNC treatment, including their mechanisms of action, preclinical and clinical studies, challenges, and future directions. Future oncolytic virotherapy focuses on improving delivery and specificity through nanoparticle carriers and genetic modifications to enhance tumor targeting and immune response. Combining different OVs and integrating them with immunotherapies, such as checkpoint inhibitors, could overcome tumor resistance and improve outcomes. Personalized approaches and rigorous clinical trials are key to ensuring the safety and effectiveness of virotherapy in treating HNC.

Reducing the risk of unfavourable fractures in Le Fort III osteotomy via a navigation-guided technique

The aim of this study was to investigate the clinical feasibility of reducing the risk of unfavourable fractures during Le Fort III osteotomy by using a navigation-guided technique. A study was carried out involving 20 patients with Crouzon syndrome treated with Le Fort III osteotomy and distraction osteogenesis from 2018 to 2023 at the International Hospital of Peking University. The Le Fort III osteotomy procedure in experimental group (9 patients) was carried out under the guidance of navigation technique, while in historical control group (11 patients) was carried out by free hand. Immediate postoperative CT scans were acquired within 24h after surgery to observe the osteotomy lines and detect unfavourable fracture lines. There were 4 patients with unfavourable fractures in the navigation group (4/9 = 44%) while 10 patients in the freehand group (10/11 = 91%), with a statistically significant difference in the probability of unfavourable fracture and the number of fracture lines between the two groups (P < 0.05). The difference in unfavourable fracture incidence in the two groups was significant in zygomatic area (P < 0.05) while not significant in mid-palatal area (P > 0.05). And the surgical duration of the navigation group was significantly shorter than that of the freehand group (216 min vs 280 min) (P < 0.05). The above findings suggest that the navigation-guided technique is effective in reducing the risk of unfavourable fractures in Le Fort III osteotomy procedure and decreasing the surgical duration.

Intraoperative Computed Tomography in the Surgical Treatment of Zygomatic Complex Fracture: A Retrospective Cohort Study

This study aimed to assess the effectiveness of intraoperative computed tomography (ICT) in managing zygomatic complex (ZMC) fractures surgically. A total of 143 patients (84 men, 59 women; average age 37.13 y) undergoing surgical treatment for ZMC fractures participated in this retrospective cohort study, with 72 in the ICT group and 71 in the control group. There were no notable differences in gender, age, time from injury to surgery, and surgical duration between the two groups. The ICT group exhibited significantly fewer surgical approaches than the control group (1.39±0.519 vs. 2.07±0.617, P<0.001). Fixation points in the ICT group (1-point: 42, 2-point: 14, 3-point: 16) significantly differed from the control group (1-point: 15, 2-point: 17, 3-point: 39), P<0.001. Symmetry of reduction was assessed through immediate postoperative images, and stability was compared between immediate postoperative images and those taken at least 3 months later. Both assessments revealed no significant differences between the 2 groups. This study indicates that ICT facilitates prompt evaluation of ZMC reduction, minimizing the necessity for incisions and internal fixation, while achieving comparable reduction efficacy and long-term stability to conventional approaches.

Reducing the risk of tooth injury in anterior maxillary interdental osteotomy for cleft lip and palate patients using a surgical navigation technique

The aim of this study was to investigate the clinical feasibility of preventing tooth injury from anterior maxillary interdental osteotomy by using a surgical navigation technique. A retrospective review was conducted on cleft lip and palate patients treated with anterior maxillary osteotomy followed by distraction osteogenesis between August 2019 and May 2022. Patients operated on through image guidance were enrolled in the navigation group, while those who were operated on freehand were enrolled in the freehand group. Tooth injuries were identified on postoperative images. Linear and angular deviations of the osteotomy line were measured. Twelve patients were enrolled in the study, seven in the navigation group and five in the freehand group. Altogether, 24 osteotomy lines and 53 adjacent teeth were evaluated. The dental injury rate was 3% in the navigation group and 27% in the freehand group (P = 0.016). The average linear deviations (mean ± standard deviation) were 0.67 ± 0.30 mm and 2.05 ± 1.33 mm, respectively (P < 0.001), while the average angular deviations were 1.67 ± 0.68° and 11.41 ± 7.46°, respectively (P < 0.001). The results suggest that navigation was able to reduce the tooth injury risk compared with freehand interdental osteotomies in crowded dental arches.

Investigation of the accuracy of dynamic condylar position: A model study

OBJECTIVES

To evaluate dynamic condylar positions by integrating mandibular movement recording data and cone-beam computed tomography (CBCT) and to investigate its accuracy via dynamic model experiments.

METHODS

A polyvinyl chloride skull model was utilized. A robot arm was used to operate the mandible to perform mouth opening, closing, protrusion, and lateral movements. A recording device, worn on the skull, was used to record the dynamic process and an optical position tracking (OPT) system was used to simultaneously trace the movements. A self-developed software module was used to evaluate the dynamic condylar position by integrating the dynamic tracing data and a virtual skull model derived from CBCT images. Errors were defined as differences between the dynamic coordinates of six landmarks around the condylar area derived from the software module (test) and OPT system (gold standard).

RESULTS

The condylar position errors were 0.76 ± 0.31, 0.55 ± 0.15, and 0.68 ± 0.23 mm for mouth opening, bilateral, and protrusion movements, respectively. Furthermore, the errors for small, moderate, and large mouth opening movements were 0.62 ± 0.19, 0.69 ± 0.29, and 0.94 ± 0.31 mm, respectively. The errors for all movements, except for large mouth opening, were significantly less than 1 mm (P < 0.05). The error was not different from 1 mm in the large mouth opening movement (P > 0.05).

CONCLUSIONS

Our developed method of achieving dynamic condylar position by integrating mandibular movement recording data and CBCT images is clinically reliable.

CLINICAL SIGNIFICANCE

This study proved the reliability of evaluating dynamic condylar position using a commercial dynamic recording instrument and CBCT images.

Clinical Advances and Future Directions of Oncolytic Virotherapy for Head and Neck Cancer

Oncolytic viruses (OVs), without harming normal tissues, selectively infect and replicate within tumor cells, to release immune molecules and tumor antigens, achieving immune-mediated destruction of tumors and making them one of the most promising immunotherapies for cancer. Many clinical studies have demonstrated that OVs can provide clinical benefits for patients with different types of tumors, at various stages, including metastatic and previously untreatable cases. When OVs are used in combination with chemotherapy, radiotherapy, immunotherapy, and other treatments, they can synergistically enhance the therapeutic effects. The concept of oncolytic virotherapy (OVT) was proposed in the early 20th century. With advancements in genetic engineering, genetically modified viruses can further enhance the efficacy of cancer immunotherapy. In recent years, global research on OV treatment of malignant tumors has increased dramatically. This article comprehensively reviews the findings from relevant research and clinical trials, providing an overview of the development of OVT and its application in the clinical treatment of head and neck cancer. The aim is to offer insights for future clinical and fundamental research on OVT.

Current global research on mandibular defect: A bibliometric analysis from 2001 to 2021

Background: Mandibular defects can result from congenital deformities, trauma, tumor resection, and osteomyelitis. The shape was irregular because the lower jaw was radians. This involves teeth and jaw functions; therefore, the difficulty of bone repair is greater than that in other body parts. Several standard treatments are available, but they result in various problems, such as difficulties in skin flap transplantation and possible zone dysfunction, artificial material boneless combining ability, and a long treatment period. This study aimed to introduce the present status of research on mandibular defects to analyze the current introduction and predict future research trends through a bibliometric study. Methods: From 2001 to 2021, publications on mandibular defects were collected for bibliometric visualization using VOSviewer, CiteSpace, and Scimago Graphica software based on the Web of Science Core Collection. Results: This study analyzed 4,377 articles, including 1,080 published in the United States, 563 in China, and 359 in Germany, with an increase in the number of articles published over the past 20 years. Wikesjoe and Ulf Mai E had the most publications (p = 36) and citations (citations = 1,553). Shanghai Jiaotong University published the highest number of papers among the research institutions (p = 88). The most productive journal was Journal of Oral and Maxillofacial Surgery, and the cited literature was primarily classified as dentistry, dermatology, and surgery. Cluster Analysis of Co-occurrence Keywords revealed that highest number of core words were mandibular defects, mandibular reconstruction, and bone regeneration. The highest cited words were head and neck cancer, accuracy, and osteogenic differentiation. High-frequency terms of Cluster Analysis of References were osteosynthesis plate, tissue engineering, and rapid distraction rate. Conclusion: Over the past 20 years, the number of studies on mandibular defects has gradually increased. New surgical procedures are increasingly being used in clinical practice. Current frontier topics mainly focus on areas such as computer-aided design, 3D printing of osteotomy and reconstruction guide plates, virtual surgical planning, and bone tissue engineering.