Intra- and interreader variability of orbital volume quantification using 3D computed tomography for reconstructed orbital fractures

Icex: Advances in the automatic extraction and volume calculation of cranial cavities

The use of non-destructive approaches for digital acquisition (e.g. computerised tomography-CT) allows detailed qualitative and quantitative study of internal structures of skeletal material. Here, we present a new R-based software tool, Icex, applicable to the study of the sizes and shapes of skeletal cavities and fossae in 3D digital images. Traditional methods of volume extraction involve the manual labelling (i.e. segmentation) of the areas of interest on each section of the image stack. This is time-consuming, error-prone and challenging to apply to complex cavities. Icex facilitates rapid quantification of such structures. We describe and detail its application to the isolation and calculation of volumes of various cranial cavities. The R tool is used here to automatically extract the orbital volumes, the paranasal sinuses, the nasal cavity and the upper oral volumes, based on the coordinates of 18 cranial anatomical points used to define their limits, from 3D cranial surface meshes obtained by segmenting CT scans. Icex includes an algorithm (Icv) for the calculation of volumes by defining a 3D convex hull of the extracted cavity. We demonstrate the use of Icex on an ontogenetic sample (0-19 years) of modern humans and on the fossil hominin crania Kabwe (Broken Hill) 1, Gibraltar (Forbes' Quarry) and Guattari 1. We also test the tool on three species of non-human primates. In the modern human subsample, Icex allowed us to perform a preliminary analysis on the absolute and relative expansion of cranial sinuses and pneumatisations during growth. The performance of Icex, applied to diverse crania, shows the potential for an extensive evaluation of the developmental and/or evolutionary significance of hollow cranial structures. Furthermore, being open source, Icex is a fully customisable tool, easily applicable to other taxa and skeletal regions.

Application of customized integration titanium mesh in the treatment of complicated zygomatic complex fractures: A prospective randomized clinical study

The present study aimed to quantitatively evaluate the outcomes of the application of customized integration titanium mesh (CITM) in treating unilateral complicated zygomatic complex fractures. A prospective, randomized, controlled clinical study was conducted. Patients were randomly divided into the experimental group who underwent treatment with CITM, and the control group who underwent treatment just with traditional titanium plates. The X² test and student t-test were used for statistical analyses. Twenty patients who required surgery for unilateral complicated zygomatic complex fracture were included in this study. The results showed that the mean of average distance (AD) between pre- and postoperative CT measurements was 0.487 mm in the experimental group and 1.173 mm in the control group (P < 0.001). Compared with the control group, the experimental group had superior zygomatico-facial symmetry (P＜0.05), a shorter average operation time (150 min versus 229 min; P < 0.001), and a higher rate of anatomic reduction (80.0% versus 30.0%; P＜0.05). In conclusion, CITM deserves to be promoted for the treatment of complicated zygomatic complex fractures. TRIAL REGISTRATION: www.chictr.org.cn (ChiCTR1800016818).

Radiologists and Clinical Trials: Part 2: Practical Statistical Methods for Understanding and Monitoring Independent Reader Performance

Though many clinical trials rely on medical image evaluations for primary or key secondary endpoints, the methods to monitor reader performance are all too often mired in the legacy use of adjudication rates. If misused, this simple metric can be misleading and sometimes entirely contradictory. Furthermore, attempts to overcome the limitations of adjudication rates using de novo or ad hoc methods often ignore well-established research conducted over the last half-century and can lead to inaccurate conclusions or variable interpretations. Underperforming readers can be missed, expert readers retrained, or worse, replaced. This paper aims to standardize reader performance evaluations using proven statistical methods. Additionally, these methods will describe how to discriminate between scenarios of concern and normal medical interpretation variability. Statistical methods are provided for inter-reader and intra-reader variability and bias, including the adjudicator's bias. Finally, we have compiled guidelines for calculating correct sample sizes, considerations for intra-reader memory recall, and applying alternative designs for independent readers.

Implant malposition and revision surgery in primary orbital fracture reconstructions

The aim of the study was to assess factors leading to revision surgery and implant position of primary orbital fracture reconstructions. A retrospective cohort included patients who underwent orbital floor and/or medial wall fracture reconstruction for recent trauma. Demographics, fracture type, surgery and implant-related variables, and postoperative implant position were analyzed. The overall revision surgery rate was 6.5% (15 of 232 surgeries). The rate was highest in combined midfacial fractures with rim involvement (14.0%), lower in zygomatico-orbital fractures (8.7%), and lowest in isolated blowout fractures (3.8%). Fracture type, orbital rim fixation and implant malposition predicted revision. The best positioning was achieved with patient-specific milled titanium implants (mtPSI) and resorbable materials, whereas the poorest with preformed three-dimensional titanium plates. Combined midfacial fractures with rim involvement in particular have a high risk for orbital revision surgery. Within the limitations of the present study, mtPSIs should be preferred in the reconstruction of primary orbital fractures if possible.

Clinical outcome of patients with orbital fractures treated with patient specific CAD/CAM ceramic implants - A retrospective study

The aim of this study was to determine whether patients benefit from a secondary reconstruction since it carries the risks of no improvement or worsening of their current situation. Patients treated with individual computer-aided-design/computer-aided-manufacturing (CAD/CAM) ceramic implants were reviewed. To ascertain changes throughout the secondary reconstruction, the study investigators reviewed ophthalmological examinations, took volumetric measurements of the orbits and asked the patients for evaluation of their situation before and after the reconstruction. Points addressed were double vision, visual acuity, field of vision, limitations in daily life and aesthetic considerations. A total of 14 patients were reviewed and 11 answered the questionnaire. Ophthalmological examinations showed that the physical integrity of the eye was maintained. Volumetric measurements preopeatively (33.94 ± 3.24 cm³) and postoperatively (30.67 ± 2.07 cm³) showed that a statistically significant overcorrection of orbital volume leads to good functional and aesthetic outcomes. Patients' subjective opinions were that they greatly benefitted, especially concerning limitations in daily life, which improved by 4.4 ± 2.8 points out of 10 possible points, and aesthetics, with an improvement of 5.9 ± 1.78 points. Based on these findings, we conclude that secondary reconstructions contribute to improvement of the patients' quality of life and therefore should be considered as an option to improve patients' condition.

Overview of tools for the measurement of the orbital volume and their applications to orbital surgery

There are numerous applications in craniofacial surgery with orbital volume (OV) modification. The careful management of the OV is fundamental to obtain good esthetic and functional results in orbital surgery. With the growth of computer-aided design - computer-aided manufacturing (CAD-CAM) technologies, patient-specific implants and custom-made reconstruction are being used increasingly. The precise measurement of the OV before surgery is becoming a necessity for craniofacial surgeons. There is no consensus on orbital volume measurements (OVMs). Manual segmentation of computed tomography (CT) images is the most used method to determine the OV, but it is time-consuming and very sensitive to operator errors. Here, we describe the various methods of orbital volumetry validated in the literature that can be used by surgeons in preoperative planning of orbital surgery. We also describe the leading software employed for these methods and discuss clinical use (posttraumatic enophthalmos prediction and orbital reconstruction) in which OVMs are important.

Repair of orbital floor fractures via the transantral approach with osteosynthesis plate

INTRODUCTION

The most common surgical access techniques employed in patients with orbital floor fractures are associated with a risk of complications, such as implant infection, migration, epiphora, lower eyelid retraction, ectropion, diplopia worsening, retrobulbar hematoma, emphysema, "white-eyed" syndrome, enophthalmia relapse, hypoglobus, and persistent diplopia due to periorbital atrophy. Consequently, alternative access techniques precluding these complications have to be found.

STUDY OBJECTIVE

To assess the efficacy of transantral approach in the surgical treatment of patients with orbital floor fractures based on results of retrospective analysis of our clinical experience.

MATERIALS AND METHODS

We performed a retrospective study of medical records and X-ray data of 52 patients with fractures of the floor of the orbit, 18 to 68 years old, treated using transantral approach as described in the article. Titanium plates of special shape were used for orbital floor reconstruction.

RESULTS

In 94.2% of the cases, adequate restoration of the floor of the orbit was achieved. It led to regression of the ocular signs. In 4 patients, diplopia remained in extreme gaze positions, which did not require surgical correction. The failed cases were related to incorrect positioning of the plate or fixing screws. No inflammatory complications were observed.

CONCLUSION

Transantral access approach may be a technique of choice in treating patients with orbital floor fractures; it is safe, minimally traumatic, and effective in the early posttraumatic period when the injured area is located in the posterior parts of the floor of the orbit.