Accuracy of Virtual Surgical Planning in Treatment of Temporomandibular Joint Ankylosis Using Distraction Osteogenesis: Comparison of Planned and Actual Results

The Effects of Cranial Orientation on Forensic Frontal Sinus Identification as Assessed by Outline Analyses

Simple Summary

Frontal sinus patterns are unique amongst individuals. When faced with an unknown decedent, investigators can compare the frontal sinus pattern observed in postmortem radiographs to antemortem radiographs of the suspected individual to make a positive identification. Ideally, the antemortem and postmortem radiographs are oriented in the same exact position, but this can be challenging. This study investigates how slight variations in radiographic orientation affect sinus outlines and potentially impact identification. Frontal sinus models were created from CT scans (21 individuals) and digitally oriented across three clinically relevant views. From each standard orientation (looking straight ahead), eight 5° deviations were obtained in horizontal (left/right), vertical (up/down), and diagonal (e.g., left-up vs. right-down) directions. Within and between individual differences in sinus size and outline shape were assessed. Sinus breadth remained relatively stable across deviations, while sinus height was affected by small vertical deviations. Although radiographic vertical deviations resulted in statistical differences, impacts on outline matches were minimal. However, practitioners need to take particular care in matching radiographic orientation for smaller and/or discontinuous (right and left sides separated) sinuses, which are more likely to lose part of the sinus in more inferiorly oriented views and, thus, could affect various methods of sinus identification.

Abstract

The utility of frontal sinuses for personal identification is widely recognized, but potential factors affecting its reliability remain uncertain. Deviations in cranial position between antemortem and postmortem radiographs may affect sinus appearance. This study investigates how slight deviations in orientations affect sinus size and outline shape and potentially impact identification. Frontal sinus models were created from CT scans of 21 individuals and digitally oriented to represent three clinically relevant radiographic views. From each standard view, model orientations were deviated at 5° intervals in horizontal, vertical, and diagonal (e.g., left-up) directions (27 orientations per individual). For each orientation, sinus dimensions were obtained, and outline shape was assessed by elliptical Fourier analyses and principal component (PC) analyses. Wilcoxon sign rank tests indicated that sinus breadth remained relatively stable (p > 0.05), while sinus height was significantly affected with vertical deviations (p < 0.006). Mann–Whitney U tests on Euclidean distances from the PC scores indicated consistently lower intra- versus inter-individual distances (p < 0.05). Two of the three orientations maintained perfect (100%) outline identification matches, while the third had a 98% match rate. Smaller and/or discontinuous sinuses were most problematic, and although match rates are high, practitioners should be aware of possible alterations in sinus variables when conducting frontal sinus identifications.

A systematic review on the outcome of distraction osteogenesis in TMJ ankylosis

Introduction

TMJ ankylosis (TMJa) management by arthroplasty alone fails to address the deformity and the compromised airway. Distraction osteogenesis (DO) can offer a pragmatic solution to TMJa. The aim of the study was to generate evidence towards the role of DO in TMJa, evaluate its efficiency and develop an algorithm for use of DO in TMJa.

Material and methods

The research question was formulated using the PICOS statement for reporting guidelines in systematic reviews, where the efficiency of DO was evaluated in terms of mouth opening, correction of facial deformity and asymmetry, airway correction, and its long term effects.

Results

1130 articles reported DO as a treatment modality for TMJ ankylosis, of which 32 prospective studies, 16 retrospective and 2 RCTs were included in the study. DO was used for mandibular distraction in 45 studies and for simultaneous maxillamandibular distraction in only five studies. An algorithm for use of DO in TMJa was developed.

Conclusion

Although DO has proven its application in TMJ ankylosis cases, its best use is for correction of obstructive sleep apnoea. Relapse causing loss of posterior ramal height is a concern after transport DO. Prearthroplastic DO appears to best correct mandibular deformity. A maxillomandibular deformity requires simultaneous maxillomandibular distraction. However, a metanalysis is still awaited for effectiveness of DO in TMJ ankylosis.

Analysis of Actual Versus Predicated Intracranial Volume Changes for Distraction Osteogenesis Using Virtual Surgical Planning in Patients With Craniosynostosis

INTRODUCTION

The primary outcome metric in patients with craniosynostosis are changes in intracranial volumes (ICVs). In patients who undergo distraction osteogenesis (DO) to treat craniosynostosis, changes are also dependent on the length of distraction. Virtual surgical planning (VSP) has been used to predict anticipated changes in ICV during cranial vault reconstruction. The purpose of this study is to analyze the actual versus predicted ICV changes using VSP in patients who undergo DO for craniosynostosis management.

METHODS

All patients with craniosynostosis treated with DO at a single institution, Rady Children's Hospital, between December 2013 and May 2019 were identified. Inclusion criteria are as follows: VSP planning with predicted postoperative ICV values and preoperative and postdistraction CT scans to quantify ICV. Postoperative ICV and VSP-estimated ICV were adjusted for age-related ICV growth. The primary outcome measure calculated was age-adjusted percent volume change per millimeter distraction (PVCPD), and results were analyzed using paired Wilcoxon signed rank tests.

RESULTS

Twenty-seven patients underwent DO for cranial vault remodeling. Nineteen patients were nonsyndromic, and 8 patients were syndromic. The median postoperative PVCPD was 0.30%/mm, and the median VSP-estimated PVCPD was 0.36% per millimeter (P < 0.001). A subanalysis of nonsyndromic patients showed a median postoperative PVCPD of 0.29%/mm in nonsyndromic patients that differed significantly from the VSP estimate of 0.34%/mm (P = 0.003). There was also a significant difference in syndromic patients' observed PVCPD of 0.41%/mm versus VSP estimate of 0.79%/mm (P = 0.012).

CONCLUSIONS

Virtual surgical planning overestimates the change in ICV attributable to DO in both syndromic and nonsyndromic patients.

Comparison in clinical performance of surgical guides for mandibular surgery and temporomandibular joint implants fabricated by additive manufacturing techniques

Additive manufacturing (AM) offers great design freedom that enables objects with desired unique and complex geometry and topology to be readily and cost-effectively fabricated. The overall benefits of AM are well known, such as increased material and resource efficiency, enhanced design and production flexibility, the ability to create porous structures and on-demand manufacturing. When AM is applied to medical devices, these benefits are naturally assumed. However, hard clinical evidence collected from clinical trials and studies seems to be lacking and, as a result, systematic assessment is yet difficult. In the present work, we have reviewed 23 studies on the clinical use of AM patient-specific surgical guides (PSGs) for the mandible surgeries (n = 17) and temporomandibular joint (TMJ) patient-specific implants (PSIs) (n = 6) with respect to expected clinical outcomes. It is concluded that the data published on these AM medical devices are often lacking in comprehensive evaluation of clinical outcomes. A complete set of clinical data, including those on time management, costs, clinical outcomes, range of motion, accuracy of the placement with respect to the pre-operative planning, and extra complications, as well as manufacturing data are needed to demonstrate the real benefits gained from applying AM to these medical devices and to satisfy regulatory requirements.

Accuracy of virtually planned mandibular distraction in a pediatric case series

The aim of this study was to describe the utility of 3D technology in mandibular distraction (MD) for patients with mandibular hypoplasia (MH), using 3D-printed cutting guides (CGs), and to assess the differences between virtual surgical planning (VSP) and the final result. A descriptive retrospective study of five patients diagnosed with MH, who required unilateral or bilateral MD, was carried out between January 2018 and January 2020. All patients underwent preoperative craniofacial CT scan and a 3D VSP was executed. MD was performed with the help of the 3D-printed CG. Before removal of the distractor, another CT scan was performed to compare the actual final result with the VSP. A mean difference of <4° was found for the osteotomy direction, < 7° for distractor position, and <2 mm for posterior screw placement. VSP and 3D-printed CGs have revolutionized surgical planning, facilitating surgical treatment and improving the final result. In our sample, the variations in osteotomy line, distractor position, and posterior screw placement have been minor, making the outcome more predictable.

Fully-customized distraction assembly for maxillofacial distraction osteogenesis: a novel device and its experimental accuracy verification

Background

A new distraction osteogenesis assembly system comprising a fully customized CAD/CAM-based fixation unit and ready-made distraction unit was developed. The aim of this study was to introduce our new distraction system and to evaluate its accuracy level in a sampled mandibular distraction osteogenesis.

Methods

Our system consists of a fully customized CAD/CAM-based fixation plate unit with two plates for each moving and anchoring part, and a ready-made distraction unit with attachment slots for fixation plates. The experimental distractions were performed on 3D-printed mandibles for one control and two experimental groups (N = 10 for each group). All groups had reference bars on the chin region and teeth to measure distraction accuracy. The control group had the classical ready-made distraction system, and experimental groups 1 and 2 were fitted with our new distraction assembly using a different distractor-positioning guide design. All distracted experimental mandibles were scanned by CT imaging, then superimposed on a 3D simulation to get their discrepancy levels.

Results

The measured 3D distances between the reference landmarks of the surgical simulations and the experimental surgeries for the three groups were significantly different (p < 0.0001) by statistical analysis. The errors were greater in the control group (with a total average of 19.18 ± 3.73 mm in 3D distance between the simulated and actual reference points) than those in the two experimental groups (with an average of 3.68 ± 1.41 mm for group 1 and 3.07 ± 1.39 mm for group 2). The customized distraction assembly with 3D-printed bone plate units in group 1 and 2, however, did not show any significant differences between simulated and actual distances (p > 0.999).

Conclusion

Our newly-developed distraction assembly system with CAD/CAM plate for the distraction osteogenesis of the mandible produced a greater level of accuracy than that of a conventional distraction device. The system appears to address existing shortcomings of conventional distraction devices, including inaccuracy in vector-controlled movement of the system. However, it also needs to be further developed to address the requirements and anatomical characteristics of specific regions.

Distraksiyon ostegenizisi ve maksillofasyal bölge güncel uygulamaları :derleme

Distraksiyon osteogenezisi kallusu gererek yeni kemik oluşturma tekniğidir. Bu teknik ilk olarak Rus bilim adamı ortopedist İlizarov tarafından uzun kemiklerde geliştirilmiştir.Distraksiyon osteogenezisi; osteotomi periyodu, latent periyod, distraksiyon periyodu ve konsolidasyon periyodu olmak üzere 4 safhadan oluşmaktadır. Kolay, etkili ve komplikasyonu az olan bir uygulamadır. Distraksiyon osteogenezisi, maksillofasiyal cerrahide yaygın olarak kullanılabilmesi için modifikasyonlara ve geliştirmelere ihtiyaç duyulan bir tekniktir. Distraksiyon osteogenezisi tekniğinin gelişmesi için materyal ve teknik olarak birçok araştırma yapılmıştır ve birçok gelişme kaydedilmiştir. Ancak bu araştırmalar henüz tam bir kesinlik kazanmamakla beraber olumlu sonuçlar vermektedir

Association between maximum mouth opening and area of bony fusion in simulated temporomandibular joint bony ankylosis

The aim of this study was to investigate the quantitative association between active/passive maximum mouth opening (AMMO/PMMO) and the severity of simulated temporomandibular joint (TMJ) bony ankylosis. Twenty-eight male sheep were divided randomly and equally into surgical and control groups. Surgical group animals underwent bilateral TMJ osteotomy during which left lateral pterygoid muscle function was blocked. Control animals did not undergo surgery. Body weight, AMMO/PMMO, and TMJ morphological features were evaluated preoperatively and at 12 and 24 weeks post-surgery. In the surgical group, only the right TMJ complexes with maintained lateral pterygoid muscle function developed TMJ bony ankylosis. The AMMO/PMMO and end-feel distance in the surgical group were significantly lower than those in the control group (P < 0.001, both) at 12 and 24 weeks post-surgery. Moreover, AMMO (r = -0.940 and -0.952, P < 0.001, both) and PMMO (r = -0.944 and -0.953, P < 0.001, both) were negatively correlated with the area (mm²) of bony fusion post-surgery. These findings may be useful for the clinical treatment of early mandibular condyle fracture, with the use of occlusal pads/open-mouth plates to relax the lateral pterygoid muscle and block its function. When bony ankylosis developed in the TMJ, the greater the area of bony fusion, the more limited were AMMO/PMMO.