Bony Structures Research Articles

Optimizing the treatment of patients with intrinsic temporomandibular joint disorders

Temporomandibular joint (TMJ) dysfunctions are conditions in which there is a disruption in the anatomical and functional relationship between the various structures of the joint, including the articular disc, intra-articular ligaments, mandibular head and capsule. These disorders have a negative impact on the patient’s quality of life, resulting in limitations in masticatory function and articulation. The multifactorial nature of this pathology emphasizes the need for an individualized and comprehensive approach to the treatment of each patient. In most cases, treatment includes both surgical and orthopedic methods. Currently, combined treatment approaches aimed at synergistic effects are being actively developed to maximize therapeutic Results.The purpose of this study. To evaluate the efficacy of the combination of treatment with a repositioning mouthguard and the use of the hydraulic articular disk repositioning method in patients with internal TMJ disorders combined with dental row end defects.Materials and methods. The study included 6 patients with TMJ dysfunction and end defects of the dentition. The study was conducted between September 2023 and May 2024. As part of the study, each patient underwent cone beam computed tomography (CBCT) to evaluate the bony structures of the TMJ and ultrasound (US) to evaluate the soft tissue structures of this joint.Results. The CBCT data showed that the mean posterior temporomandibular joint displacement before treatment was 1.67, while this value increased to 3.02 after treatment. The US results showed a significant decrease in the mean value of mandibular head displacement after treatment ranging from 0.21 to 0.03, indicating a positive effect of treatment. In addition, there was a decrease in the difference in the size of the anterior and posterior parts of the articular disc, confirming the elimination of its displacement.Conclusion. The treatment combination of using a repositioning mouth guard with the hydraulic repositioning method brought about a synergistic effect on the restoration of TMJ function.

Robotic Pedicle Screw Placement with 3D MRI Registration: Moving Towards Radiation Free Robotic Spine Surgery

BACKGROUND CONTEXTPreoperative imaging for lumbar spine surgery often includes magnetic resonance imaging (MRI) for soft tissues and computer tomography (CT) for bony detail. While CT scans expose patients to ionizing radiation, whereas MRI scans do not. Emerging MRI techniques allow CT-like three-dimensional (3D) visualization of bony structures, potentially removing the need for ionizing radiation from CT scans. PURPOSEThis study aims to explore the accuracy of robot-assisted lumbar pedicle screw placement based on preoperative CT-like 3D MRI as the data source for robotic registration. STUDY DESIGNHuman cadaveric study. METHODS: CT-like 3D MRI scans of the lumbar spine were acquired in ten human cadavers. A robotic navigation platform was used to plan and navigate pedicle screw placement based on the CT-like 3D MRI. Postoperative CT scans assessed the accuracy of screw positioning compared to preoperative planning based on the Gertzbein-Robbins scale (GRS) and by direct measurement (mm). RESULTSA total of 100 lumbar pedicle screws were robotically placed in ten cadavers (L1 through L5 bilaterally) based on CT-like 3D MRI. On postoperative CT evaluation, 99.0% of the positioned screws achieved an acceptable grade on the GRS (Grade A: n = 89 or Grade B: n = 10), with 89.0% classified as Grade A and 10.0% as Grade B. Meaning that 89.0% of screws were fully contained within the pedicle (GRS A), and 10% had a minor cortical breach <2mm (GRS B). The median deviation from the planned trajectory was 0.2 mm (axial IQR: 0.1 to 0.5 mm; sagittal: IQR: 0.1 to 0.4 mm), in both axial and sagittal planes. CONCLUSIONThis study showed that image registration of CT-like 3D MRI for robotic-assisted spine surgery is technically feasible and that accurate pedicle screw placement can be achieved without preoperative CT. Each CT-like 3D MRI was successfully registered for robotic navigation. CLINICAL SIGNIFICANCEThe results suggest that CT-like 3D MRI has the potential to be a radiation-free alternative for preoperative planning and navigation in lumbar spine instrumentation procedures.

Imaging Pearls and Findings After Prior Shoulder Stabilization

This chapter emphasizes the significance of advanced imaging techniques, particularly MRI, in diagnosing the underlying causes of failed stabilization, such as recurrent labral tears, capsular deficiency, and glenoid bone loss. Key criteria for evaluating labral integrity post-surgery are discussed, alongside the importance of assessing the capsule and inferior glenohumeral ligament for signs of laxity or tears. Advanced MRI methodologies enable precise assessment of bony structures, while the interplay of imaging findings with history informs clinical decisions regarding revision surgery. Ultimately, integrating advanced imaging examination and surgical expertise can enhance patient outcomes and contribute to long-term shoulder functionality.

A novel classification of congenital cervicothoracic scoliosis: identification of coronal subtypes and their prognostic significance.

To propose a novel classification system for stratifying coronal curve patterns in congenital cervicothoracic scoliosis with hemivertebrae (CTS-HV). Type A: regional cervicothoracic deformity only disturbing the balance of head-neck-shoulder complex; Type B: cervicothoracic deformity with significant trunk tilt to the convex side; Type C: cervicothoracic deformity with a significant compensatory thoracic curve. The reliability and reproducibility were assessed via the Kappa test. The differences among different subtypes in deformity parameters and bony structures were compared to identify the causative factors predisposing to different subtypes. 98 patients were classified into Type A (47 cases), Type B (31 cases), and Type C (20 cases). The Kappa test showed excellent reliability (Kappa value = 0.847) and reproducibility (Kappa value = 0.881). The proportions of Klippel-Feil syndrome in Types B (71.0%) and C (85.0%) were significantly higher than in Type A (46.8%; all P < 0.05). Type A (66.0%) and Type B (71.0%) predominantly had their hemivertebra (HV) at T3 or T4, while Type C (75%) mostly had HV at T1 or T2. Type B exhibited the most severe trunk tilt, head shift, neck tilt, head tilt, and coronal balance distance (all P < 0.05). Type C had the lowest T1 tilt and first rib angle despite the greatest cervicothoracic Cobb angle (all P < 0.05). This novel reliable classification allows a better understanding of structural diversity and different coronal compensatory mechanisms for the natural progression of CTS-HV. It can contribute to determining the individualized treatment strategy and standardizing academic communication for this rare clinical entity.

Evaluating the efficacy of a cost-effective, fully three-dimensional-printed vertebra model for endoscopic spine surgery training for neurosurgical residents.

A fused deposition modeling three-dimensional (3D)-printed model of the L4-5 vertebra for lumbar discectomy was designed. The model included separately printed dura mater, spinal cord, ligamentum flavum, intervertebral disc (from thermoplastic polyurethane), and bony structures (from polylactic acid), and the material cost approximately US$ 1 per model. A simple plumbing endoscope was used for visualization. Dura mater injury was assessed by painting two layers on the dura mater, which peeled off with trauma. Endoscopic spine surgery is a subject of high interest in neurosurgery given its minimally invasive nature; however, it has a steep learning curve. This study evaluated the effectiveness of a cost-efficient 3D-printed model when teaching this technique to neurosurgery residents. Only a few studies have investigated the efficacy of such a model. Eight residents with >2 years of training participated. Residents performed the procedure bilaterally and twice at 1-week intervals. From the 32 surgeries, four were excluded because of facet removal (as it widened the surgical corridor), leaving 28 surgeries for analysis. Initial surgeries demonstrated a mean operation time of 21 minutes 18 seconds (standard deviation [SD], 2 minutes 32 seconds), which improved to a mean of 6 minutes 45 seconds (SD, 37 seconds) in the fourth surgery (F(3, 17)=19.18, p <0.0001), demonstrating a significant reduction in surgical time over successive surgeries. The median area with the paint removed decreased, from 161.80 (85.55-217.83) to 95.13 mm2 (12.62-160.54), (F(2.072, Inf)=2.04, p =0.128); however, this was not significant. Resident feedback indicated high satisfaction with the educational value of the model. The developed fully 3D-printed model provides a viable and scalable option for neurosurgical training programs, enhancing the learning experience while maintaining low costs. This model may be an excellent stepping stone for learning lumbar spine endoscopy, acclimating to the two-dimensional view, progressing to cadaver models, and, eventually, independent surgery.

Dentigerous cysts in horses: A retrospective study

SummaryBackgroundDentigerous cysts are well‐known congenital defects in horses, and the literature on this condition is extensive. Recently, a third type of dentigerous cyst, associated with an exostosis arising from the temporal bone, has been described. Today, computed tomography (CT) is often available and provides detailed information about the exact location and extent of dentigerous cysts, allowing for the description of new findings.Study designThis is a case series outlining the clinical, radiographic and computed tomographic features of dentigerous cysts in seven horses presented to the Equine Clinic at the Vetsuisse Faculty, University of Zurich, Switzerland.ObjectivesThe aim of this case series was to describe the radiographic and computed tomographic findings, and the occurrence of exostoses arising from the temporal bone, in horses with dentigerous cysts.MethodsThe medical records of the Equine Hospital at the University of Zurich were reviewed for horses admitted with dentigerous cysts between 2007 and 2023. Data collected and analysed included patient signalment, clinical history, clinical signs and their duration prior to referral, diagnostic imaging results, treatment and outcomes.ResultsThe most common location for the cysts was the base of the ear, although in one case, the maxillary sinus was involved. Of the seven cases, four were Icelandic horses. CT proved superior to standard radiography for determining the extent and precise location of the cysts, as well as for identifying dental material and exostoses in the temporal region. CT also facilitated detailed surgical planning. All cysts were surgically removed with good long‐term outcomes.Main limitationsOverall, the incidence of dentigerous cysts in horses was low. The relatively high occurrence of dentigerous cysts in Icelandic horses in this study is an interesting finding, though the small sample size calls for further research.ConclusionsTwo of the cases in this series were similar to a recently described variant of a ‘temporal dentigerous cyst associated with an exostosis in the temporal region’ and were closely connected to the bony structure and draining tract.

Accuracy of pelvic bone segmentation for 3d printing: a study of segmentation accuracy based on anatomic landmarks to evaluate the influence of the observer.

3D printing has a wide range of applications and has brought significant change to many medical fields. However, ensuring quality assurance (QA) is essential for patient safety and requires a QA program that encompasses the entire production process. This process begins with imaging and continues on with segmentation, which is the conversion of Digital Imaging and Communications in Medicine (DICOM) data into virtual 3D-models. Since segmentation is highly influenced by manual intervention the influence of the users background on segmentation accuracy should be thoroughly investigated. Seventeen computed tomography (CT) scans of the pelvis with physiological bony structures were identified, anonymized, exported as DICOM data sets, and pelvic bones were segmented by four observers with different backgrounds. Landmarks were measured on DICOM images and in the segmentations. Intraclass correlation coefficients (ICCs) were calculated to assess inter-observer agreement, and the trueness of the segmentation results was analyzed by comparing the DICOM landmark measurements with the measurements of the segmentation results. The correlation between segmentation trueness and segmentation time was analyzed. The lower limits of the 95% confidence intervals of the ICCs for the seven landmarks analyzed ranged from 0.511 to 0.986. The distance between the iliac crests showed the highest agreement between observers, while the distance between the ischial tuberosities showed the lowest. The distance between the upper edge of the symphysis and the promontory showed the lowest deviation between DICOM measurements and segmentation measurements (mean deviations < 1mm), while the intertuberous distance showed the highest deviation (mean deviations 14.5-18.2mm). Investigators with diverse backgrounds in segmentation and varying experience with slice images achieved pelvic bone segmentations with landmark measurements of mostly high agreement in a setup with high realism. In contrast, high variability was observed in the segmentation of the coccyx. In general, interobserver agreement was high, but due to measurement inaccuracies, landmark-based approaches cannot conclusively show that segmentation accuracy is within a clinically tolerable range of 2mm for the pelvis. If the segmentation is performed by a very inexperienced user, the result should be reviewed critically by the clinician in charge.

Biodegradable Polycaprolactone Bone Scaffold for Rhinoplasty in Bilateral Cleft Repair: A Case Report

Cleft nasal deformities are commonly observed in patients with unilateral or bilateral cleft lip, presenting various degrees of severity. Correcting nasal deformities, particularly in bilateral cleft lip patients, remains a complex challenge due to underlying anatomical abnormalities and the scarring from previous surgeries. This research aims to evaluate the effectiveness of secondary cleft rhinoplasty, focusing on addressing the hypoplastic and depressed bony structures critical to nasal projection. In many cases, autologous grafts, such as cartilage from the septum, ear, or rib, are traditionally used for nasal reconstruction. However, these materials present challenges, including donor site morbidity and tissue resorption. In this study, we explore the use of Osteopore™, a biodegradable polycaprolactone scaffold, as a bone substitute for nasal reconstruction. The results indicate that Osteopore™ offers a promising alternative with reduced morbidity and stable long-term outcomes. This method provides new insights into the materials and techniques for addressing cleft nasal deformities in bilateral cleft lip patients, potentially improving both aesthetic and functional outcomes.

Predictors of nasolacrimal duct intubation failure for primary acquired nasolacrimal duct obstruction: a computed tomography-dacryocystography (CT-DCG) study.

Making a choice between nasolacrimal duct intubation and dacryocystorhinostomy (DCR) for primary acquired nasolacrimal duct obstruction (PANDO) is an important issue in clinical practice. This study aimed to determine the potential lacrimal sac characteristics that could be used as predictors of unsuccessful intubation for PANDO based on computed tomography-dacryocystography (CT-DCG). In this retrospective comparative observational study, we included PANDO patients with a history of failed intubation for nasolacrimal duct obstruction as the intubation failure group and PANDO patients without a history of intubation as the control group. We analyzed the lacrimal sac height, lacrimal sac width, and obstruction site based on CT-DCG, all measured based on several reference levels on axial sections (upper, intermediate, lower level, common canaliculus level, and lowermost contrast level), which were defined according to the contrast and the bony structure. A total of 114 sides of the PANDO were studied, including 36 in the intubation failure group and 78 in the control group. The intubation failure group showed a smaller lacrimal sac height (11.69±4.59 mm) and width (2.28±1.97 mm, intermediate level) than the control group (14.13±2.92, 3.32±2.02 mm, P=0.005 and 0.012, respectively). The intubation failure group had a higher obstruction site than the control group (P=0.009). A small lacrimal sac and high obstruction site are predictors of nasolacrimal duct intubation failure in PANDO. For PANDO patients with a small lacrimal sac or a high obstruction position, DCR is recommended as opposed to intubation.

Setup errors analysis in iterative kV CBCT: A clinical study of cervical cancer treated with Volumetric Modulated Arc Therapy.

This study aims to analyze setup errors in pelvic Volumetric Modulated Arc Therapy (VMAT) for patients with non-surgical primary cervical cancer, utilizing the onboard iterative kV cone beam CT (iCBCT) imaging system on the Varian Halcyon 2.0 ring gantry structure accelerator to enhance radiotherapy precision. We selected 132 cervical cancer patients who underwent VMAT with daily iCBCT imaging guidance. Before each treatment session, a registration method based on the bony structure was employed to acquire iCBCT images with the corresponding planning CT images. Following verification and adjustment of image registration results along the three axes (but not rotational), setup errors in the lateral (X-axis), longitudinal (Y-axis), and vertical (Z-axis) directions were recorded for each patient. Subsequently, we analyzed 3642 iCBCT image setup errors. The mean setup errors for the X, Y, and Z axes were 4.50±3.79mm, 6.08±6.30mm, and 1.48±2.23mm, respectively. Before correction with iCBCT, setup margins based on the Van Herk formula for the X, Y, and Z axes were 6.28, 12.52, and 3.26mm, respectively. In individuals aged 60 years and older, setup errors in the X and Y axes were significantly larger than those in the younger group (p<0.05). Additionally, there is no significant linear correlation between setup errors and treatment fraction numbers. Data analysis underscores the importance of precise Y-axis setup for cervical cancer patients undergoing VMAT. Radiotherapy centers without daily iCBCT should appropriately extend the planning target volume (PTV) along the Y-axis for cervical cancer patients receiving pelvic VMAT. Elderly patients exhibit significantly larger setup errors compared to younger counterparts. In conclusion, iCBCT-guided radiotherapy is recommended for cervical cancer patients undergoing VMAT to improve setup precision.

Clinical and radiographic results of internal fixation of quadrilateral plate fractures of acetabulum.

Quadrilateral plate (QLP) is a relatively thin bony structure located below the pelvic brim proximal to the hip joint, so management of its fractures is challenging. Evaluation of the functional and radiological outcomes of internal fixation of quadrilateral plate acetabular fractures; comparison of two methods of fracture fixation. A prospective multicentric study including 30 patients who underwent open reduction and internal fixation of QLP fractures through modified Stoppa approach. Patients were divided into two groups according to the method of fixation (anatomical QLP plate vs suprapectineal and infrapectineal plates). Post-operative quality of reduction was evaluated using Matta score. Radiographical assessment according Matta's grading criteria and clinical outcome assessment using the Harris Hip Score (HHS) were repeated at follow-up and at one year to assess displacement. Mean age of patients was 34.9 ± 12.1years. After one year follow-up, clinically mean HHS was 88. ± 5.74. Radiologically post-operative reduction quality was anatomical in 21 (70%) patients, satisfactory in eight (26.7%) patients and unsatisfactory in one (3.3%) patient. Matta's grading at the last follow-up was excellent in 21 (70%) patients, good in six (20%), fair in two (6.7%) patients and poor in one (3.3%) patient. No significant difference was recorded between the two groups in terms of radiographical and clinical results and rate of complications. Accurate reduction of quadrilateral plate fracture with secure fixation through modified Stoppa approach provides good and reproducible outcomes with few complications regardless the type of the implant.

Evaluation of a radiological grading system for the early detection of total knee arthroplasties at risk for revision surgery.

X-rays are regularly performed after primary total knee arthroplasty (TKA). While soft tissue management and ligament tension cannot be evaluated, important information, such as inadequate component positioning and loose cement location, as well as subsequent loosening, can be detected. The aim of this study was to correlate radiological findings, referring to the radiological grading system (previously published by the same study group, henceforth abbreviated as "RGS"), with long-term outcomes and implant survival. A total of 266 patients who underwent titanium-coated TKA were included. In addition to implant survival, visual analogue scale score, Tegner activity score, knee society score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index, and short form-12 score as well as range of motion were evaluated. Clinical examination as well as anterior-posterior, lateral, full-length weight bearing, and patellar view radiographs were performed pre- and postoperatively, at the 3-, 6-, and 12-month postoperative follow-ups and at the final follow-up. The radiological grading system was evaluated and correlated with long-term outcome and survivorship. The revision-free survival rate was 88.4% at a median follow-up of 9.8 years (IQR: 9.3-10.3 years; range: 0.1-11.8 years). Revision surgery was required in 31 TKAs (11.7%). The multivariate Cox regression model showed a significant association between an RGS score ≥ 3 deviation points (DP) and an increased risk for revision (hazard ratio: 2.092; 95% CI: 1.020-4.290; p = 0.044). Moreover, the KSS for pain was significantly worse in patients with a RGS score ≥ 3 DP (median, 85 [74-92] vs. 90 [80-94]; p = 0.007). This is the first study indicating that deviation in component positioning, having an inadequate long leg axis, the presence of free cement or residual bony structures on postoperative X-rays significantly correlate with TKA outcome and implant survival. Therefore RGS can be of high predicable value for the survivorship of the prosthesis. Level IV - retrospective cohort study.

MUsculo-Skeleton-Aware (MUSA) deep learning for anatomically guided head-and-neck CT deformable registration

Deep-learning-based deformable image registration (DL-DIR) has demonstrated improved accuracy compared to time-consuming non-DL methods across various anatomical sites. However, DL-DIR is still challenging in heterogeneous tissue regions with large deformation. In fact, several state-of-the-art DL-DIR methods fail to capture the large, anatomically plausible deformation when tested on head-and-neck computed tomography (CT) images. These results allude to the possibility that such complex head-and-neck deformation may be beyond the capacity of a single network structure or a homogeneous smoothness regularization. To address the challenge of combined multi-scale musculoskeletal motion and soft tissue deformation in the head-and-neck region, we propose a MUsculo-Skeleton-Aware (MUSA) framework to anatomically guide DL-DIR by leveraging the explicit multiresolution strategy and the inhomogeneous deformation constraints between the bony structures and soft tissue. The proposed method decomposes the complex deformation into a bulk posture change and residual fine deformation. It can accommodate both inter- and intra- subject registration. Our results show that the MUSA framework can consistently improve registration accuracy and, more importantly, the plausibility of deformation for various network architectures. The code will be publicly available at https://github.com/HengjieLiu/DIR-MUSA.

Does the calcar femorale affect the position of uncemented short stems?

Metaphyseal-stabilised short stems rely on sufficient metaphyseal fixation and are inserted by following the medial cortex. This type of stem is used extensively in our institution, and we observed on occasion unintended implant positioning with an increased distance between the implant and the medial cortex. A bony structure within the proximal femur which was first described in 1874 and named the calcar femorale, coincides with this phenomenon.The aim of this study was to investigate the impact of the calcar femorale on the position of a metaphyseal-stabilised short stem. The frequency of cases with an increased distance between medial cortex and the implanted short stem was analysed in 52 consecutive patients. Additionally, we performed an anatomical CT study with 60 cadaveric femora to obtain more detailed information on the anatomy of the calcar femorale. Detailed measurements regarding the calcar femorale and its relationship to the proximal femur were obtained. From this, we derived implications for the implantation of a short stem prosthesis. In 50% of all cases, we found an increased gap between the stem and the medial cortex. An increased gap did not significantly affect stem size, position, or subsidence rate, but in cases with an increased gap we found fewer stems with a radiologically optimum fit. The calcar could be identified in all 60 cadavers. The calcar femorale angle showed a high correlation with the mechanical antetorsion (0.87, p = 0.02) and the functional antetorsion (0.86, p = 0.05) of the femur. The calcar femorale is a consistent anatomical structure which may be the cause for an increased gap medial to the short stem in 50% of our cases. It limits the intramedullary space and influences both stem size and orientation. The CF angle which correlates with femoral antetorsion may influence the anteversion of the stem.

A Computerized Tomography-Based Analysis of Spinal Canal Diameter to Study Its Implication on Cervical Spine Stenosis in Western Indian Population: A Retrospective Study

Abstract Background The cervical spine is prone to various conditions necessitating early detection. Morphometric analysis through computed tomography (CT) scans plays a pivotal role in diagnosing and preventing severe diseases. This study focuses on understanding the morphometric details of the cervical canal in the West Indian population, addressing a geographical gap in existing literature. The primary objective of this study was to perform a morphometric analysis of the cervical spine to study the implications it can have on cervical canal stenosis in the West Indian population. Materials and Methods This study utilizes imaging data from the CT database of 100 individuals (73 men and 27 women). Measurements such as transverse canal diameter, sagittal canal diameter, cross-sectional canal surface area (CSA), and vertebral body diameter (VBD) were collected and the Pavlov-Torg ratio (PTR) was calculated from C2 to C7. Results Notable findings include significant differences in CSA and VBD between genders, while PTR indicated cervical damage in 40% of participants. Multinomial regression was applied which signified an association between weakness and PTR. Conclusion This study can be used to highlight the CT scan's importance in studying bony structures and the call for more region-specific morphometric studies. The variations in morphometric parameters could provide insights into understanding the vulnerabilities of a population belonging to a particular geographic area, in our case, the West Indian population.

Vascular Anomalies and Congenital Infiltrating Lipomatosis May Affect Dental Maturation and Development - a Case Control Study.

Vascular anomalies are often associated with hypertrophy and asymmetry of soft tissues and bony structures. The aim of this retrospective cross-sectional radiographic study was to evaluate dental maturation and development in patients with facial vascular anomalies and congenital infiltrating lipomatosis. A sample of 342 patients with different vascular anomalies or congenital infiltrating lipomatosis involving the head and neck area was narrowed down to 31 patients with dental panoramic radiographs taken in the mixed dentition. A control group of 172 age-matched healthy subjects was used. Individual permanent teeth were given a maturation score from 1 to 12 and alveolar eruption stage according to Haavikko et al. 1970. The laterality of the anomaly was noted if applicable. Differences in dental development between affected and unaffected sides were recorded. The study data included both syndromic and non-syndromic vascular anomalies as well as congenital infiltrating lipomatosis and segmental odontomaxillary dysplasia. Teeth on the side of the anomaly were more developed and the eruption of teeth was accelerated with canines, premolars and second molars being most affected. Interestingly all the patients with Sturge-Weber syndrome (n = 4) and infiltrating lipomatosis (n = 2) showed accelerated dental maturation of multiple permanent teeth on the side of the anomaly. Hypodontia, dental root resorption and macrodontia were also found. Accelerated development and eruption of permanent teeth unilaterally in patients with vascular anomalies and congenital infiltrating lipomatosis may have a significant impact on the developing occlusion and should be thus followed by an orthodontist.

Enhancing educational experience through establishing a VR database in craniosynostosis: report from a single institute and systematic literature review.

Craniosynostosis is a type of skull deformity caused by premature ossification of cranial sutures in children. Given its variability and anatomical complexity, three-dimensional visualization is crucial for effective teaching and understanding. We developed a VR database with 3D models to depict these deformities and evaluated its impact on teaching efficiency, motivation, and memorability. We included all craniosynostosis cases with preoperative CT imaging treated at our institution from 2012 to 2022. Preoperative CT scans were imported into SpectoVR using a transfer function to visualize bony structures. Measurements, sub-segmentation, and anatomical teaching were performed in a fully immersive 3D VR experience using a headset. Teaching sessions were conducted in group settings where students and medical personnel explored and discussed the 3D models together, guided by a host. Participants' experiences were evaluated with a questionnaire assessing understanding, memorization, and motivation on a scale from 1 (poor) to 5 (outstanding). The questionnaire showed high satisfaction scores (mean 4.49 ± 0.25). Participants (n = 17) found the VR models comprehensible and navigable (mean 4.47 ± 0.62), with intuitive operation (mean 4.35 ± 0.79). Understanding pathology (mean 4.29 ± 0.77) and surgical procedures (mean 4.63 ± 0.5) was very satisfactory. The models improved anatomical visualization (mean 4.71 ± 0.47) and teaching effectiveness (mean 4.76 ± 0.56), with participants reporting enhanced comprehension and memorization, leading to an efficient learning process. Establishing a 3D VR database for teaching craniosynostosis shows advantages in understanding and memorization and increases motivation for the study process, thereby allowing for more efficient learning. Future applications in patient consent and teaching in other medical areas should be explored.

Automatic bony structure segmentation and curvature estimation on ultrasound cervical spine images - a feasibility study

Abstract The loss of cervical lordosis is a common degenerative disorder known to be associated with abnormal spinal alignment. In recent years, ultrasound (US) imaging has been widely applied in the assessment of spine deformity and has shown promising results. The objectives of this study are to automatically segment bony structures from the 3D US cervical spine image volume and to assess the cervical lordosis on the key sagittal frames. In this study, a portable ultrasound imaging system was applied to acquire cervical spine image volume. The nnU-Net was trained on to segment bony structures on the transverse images and validated by 5-fold-cross-validation. The volume data were reconstructed from the segmented image series. An energy function indicating intensity levels and integrity of bony structures was designed to extract the proxy key sagittal frames on both left and right sides for the cervical curve measurement. The mean absolute difference (MAD), standard deviation (SD) and correlation between the spine curvatures of the left and right sides were calculated for quantitative evaluation of the proposed method. The DSC value of the nnU-Net model in segmenting ROI was 0.973. For the measurement of 22 lamina curve angles, the MAD±SD and correlation between the left and right sides of the cervical spine were 3.591±3.432° and 0.926, respectively. The results indicate that our method has a high accuracy and reliability in the automatic segmentation of the cervical spine and shows the potential of diagnosing the loss of cervical lordosis using the 3D ultrasound imaging technique.

Pre- and postoperative intracranial volumes in children with non-syndromic craniosynostosis using 3D volumetric technique

Introduction: Corrective surgery for craniosynostosis presents several challenges to students during their training, with obtaining practical experience being one of the main obstacles. The neurocranium is formed by the bony structures that surround the brain, thus ensuring its protection. During the first years of life, the baby's skull grows exponentially. Understanding the normal growth and development of the cranial shape is essential for monitoring cranial development, detecting abnormalities, and evaluating the long-term results of craniosynostosis surgery. Objectives: To study the cranial volume gained after surgical treatment of craniosynostosis using 3D printing technology. Methodology: 26 patients who underwent craniosynostosis surgery, from 2019 to 2022 were selected. Preoperative, immediate, and late postoperative (3 months) tomography examination was performed. Reconstructing the exams using the Blender program with cranial volume calculation. 3D printing of skulls using Sethi 3D printer. Evaluation of results using Student's t-test with independent samples. Results: The study involved 26 patients, with ten presenting scaphocephaly treated with Renier's "H" cranial remodeling, five with trigonocephaly, five with plagiocephaly, and two with brachycephaly treated with front-orbital advancement (FOA). Cranial volumes were measured before and after surgery. For patients undergoing Renier's "H" treatment, there was an average increase of 224 cm³ between the late postoperative and preoperative stages, with smaller differences between the immediate postoperative and preoperative stages. For those treated with FOA, the average difference between late postoperative and preoperative stages was 138.8 cm³, while between immediate postoperative and preoperative stages was 129.7 cm³. Conclusion: Cranial volume gained by patients undergoing Renier's h technique and Fronto-orbital advancement is significant, showing that it may be possible to use less invasive techniques to take advantage of patients' natural volumetric gain.

Modified colored three-dimensional posterior and temporal cranial fossa model with mobility of the joint between C1 and occipital condyle

BackgroundSkull base surgery requires anatomical knowledge and appropriate surgical technique in bone drilling. We developed a newly modified three-dimensional (3D) model of the posterior cranial fossa as a learning tool that improves knowledge of skull base anatomy and surgical approaches, including skull base drilling techniques. MethodsThis bone model of the posterior cranial fossa was created based on computed tomography data using a 3D printer, and incorporates artificial cranial nerves, cerebral vessels, bony structures, dura mater, and cerebellar tentorial dura. These anatomical components are differentiated with various colors. In addition, the atlanto-occipital junction can be mobilized to fully expose the surface of the cartilage between the C1 condyle and occipital condyle to allow drilling to open the hypoglossal canal under a wide surgical field. The usefulness of the model for practicing skull base surgical approaches was evaluated. ResultsExperience of bone drilling, dural dissection, and 3D positioning of important structures, including cranial nerves and blood vessels, was identical to that in actual surgery. ConclusionsThis model is designed to facilitate teaching anatomical knowledge and essential epidural procedure-related skills, and is useful for teaching the essential elements of posterior skull base surgery.