Predicting clinical outcomes using morphometric changes in adults with complex Chiari malformation undergoing occipitocervical fusion with or without ventral decompression: patient series

BACKGROUND The authors assessed the connection between clinical outcomes and morphometrics in patients with complex Chiari malformation (CM) who have undergone posterior fossa decompression (PFD) and subsequent occipitocervical fusion (OCF) with or without ventral decompression (VD). OBSERVATIONS The authors retrospectively reviewed 33 patients with CM aged over 21 years who underwent PFD and OCF with or without endoscopic endonasal odontoidectomy at the authors’ institution (21 OCF only and 12 OCF + VD). Clivoaxial angle (CXA), pB-C2 (perpendicular line to the line between the basion and C2), atlantodental interval (ADI), basion-dens interval (BDI), basion-axial interval (BAI), and C1 canal diameter were measured on preoperative and approximately 3-month postoperative computed tomography or magnetic resonance imaging scans. Common symptoms included headache, paresthesia, and bulbar symptoms. Clinical improvement after surgery was observed in 78.8% of patients. CXA, ADI, and BDI all significantly increased after surgery, whereas pB-C2 and BAI significantly decreased. OCF + VD had a significantly more acute CXA and longer pB-C2 preoperatively than OCF only. Patients who clinically improved postoperatively showed the same significant morphometric changes, but those who did not improve showed no significant morphometric changes. LESSONS Patients showing improvement had greater corrections in skull base morphometrics than those who did not. Although there are various mutually nonexclusive reasons why certain patients do not improve after surgery, smaller degrees of morphometric correction could play a role.

findPC: An R package to automatically select number of principal components in single-cell analysis

Principal component analysis (PCA) is widely used in analyzing single-cell genomic data. Selecting the optimal number of PCs is a crucial step for downstream analyses. The elbow method is most commonly used for this task, but it requires one to visually inspect the elbow plot and manually choose the elbow point. To address this limitation, we developed six methods to automatically select the optimal number of PCs based on the elbow method. We evaluated the performance of these methods on real single-cell RNA-seq data from multiple human and mouse tissues. The perpendicular line method with 20 PCs has the best overall performance, and its results are highly consistent with the numbers of PCs identified manually. We implemented the six methods in an R package, findPC, that objectively selects the number of PCs and can be easily incorporated into any automatic analysis pipeline.

Incisor root length in individuals with and without anterior open bite: a comparative CBCT study

ABSTRACT Objective: This study aimed to compare the root length of maxillary and mandibular incisors between individuals with open bite versus matched individuals with adequate overbite. Methods: This comparative, matched and retrospective study included 48 cone beam computed tomographies (CBCTs) obtained at a university radiological center. Scans belonged to 24 individuals with open bite (overbite ≤ 0 mm) and 24 individuals with adequate overbite (controls). Both groups were matched by age, sex, malocclusion classification and skeletal characteristics (ANB and FMA angles). Root length of each maxillary and mandibular incisor was measured in millimeters (mm) in a sagittal section from a perpendicular line to the enamel cement junction until the root apex (384 length measurements were made). The means of root length in both groups were compared using t-tests. In addition, correlations between variables were evaluated with the Pearson correlation coefficient (α = 0.05). Results: In both groups, the root length of the upper central incisors was approximately 12 mm and the root length of the maxillary lateral incisors was approximately 13 mm (p˃ 0.05). Likewise, the root length of lower central incisors in both groups measured approximately 12 mm (p˃ 0.05). However, the mandibular lateral incisor roots of open bite patients were significantly longer than in the normal overbite patients (approximately 1 mm, p= 0.012 right side, p= 0.001 left side). Conclusions: Root length of maxillary incisors and central mandibular incisor is similar in individuals with or without open bite, but the mandibular lateral incisor roots in open bite patients were significantly longer than in the normal overbite patients.

Moorrees-like mesh diagram for Romanian patients - a pilot study

diagrams to ease the orthodontic diagnosis and treatment of North-American patients. Subsequently, the system was adapted by different authors to other races and populations. The objective of this study is to provide a system of Moorrees-like mesh diagrams for the Romanian population, Caucasian race, which would help orthodontists, surgeons and prosthetists. Methods. 40 patients were introduced in the study, 20 males and 20 females, with ages between 12-33 years, permanent dentition and slight dental-maxillary abnormalities, class I and II Angle. For each patient, a lateral cephalometric radiograph was taken, with CRANEX 3D, head straight, maximum intercuspation. On tracing paper were drawn 35 anthropometric points and 3 planes, Frankfurt plane, as the horizontal landmark, a perpendicular line through nasion as the vertical landmark and the occlusal plane. From each point we measured the distance in millimeters to the horizontal landmark and to the vertical landmark, respectively. The obtained values were introduced into 40 tables, using Microsoft Office Excel 2007 and 3 arithmetic means were calculated, for males, for females and a general one, for children under 12 years old. The arithmetic means were transferred on millimetric paper and tracing paper, joining the obtained points and completing the templates. Results. Three different Moorrees-like mesh diagrams were obtained, one for male, one for female and a mixt one for children under 12 years, Romanian patients, Caucasian race, respectively. Conclusions. Mesh diagram comes in the support of a better perspective of the anatomical elements of the face and the facial growth, being a useful tool in predicting treatment. Computer based programs with Moorrees-like diagrams adapted to Romanian patients may be the object of further studies.

Horizontal Cervix as a Novel Sign for Predicting Adhesions on the Posterior Extrauterine Wall in Cases of Placenta Previa

We aimed to identify a magnetic resonance imaging (MRI) feature that can predict posterior extrauterine adhesion (posterior adhesion) antenatally, in patients with placenta previa. We retrospectively reviewed patients with placenta previa who underwent a preoperative MRI examination of placenta accreta spectrum. We categorized the patients into two groups based on whether the cervix was anterior or posterior to a line perpendicular to the anatomical conjugate on the MRI. We projected the perpendicular line toward a straight line through the broad of the back on T2-weighted sagittal MRI images and measured the angle between this line and the line passing through the cervical canal. We analyzed the correlation of the cervical canal angle with the presence of posterior adhesions. Of the 96 patients analyzed, 71 patients had an anteverted cervix and 25 patients had a retroverted cervix. There were 21 posterior adhesions. The adhesion rate was significantly higher in patients with a retroverted cervix than those with an anteverted cervix (8.5% vs. 60%; p = 0.00). The cervical canal angle was ≤10° in 25 patients; of these 17 had adhesions (sensitivity, 81.0%; specificity, 89.3%; area under the curve, 0.887; 95% confidence interval, 0.792–0.981). This finding, labeled “positive horizontal cervix sign,” may be a promising indicator of posterior adhesions in patients with placenta previa.

The Assessment of Reduction Status Using Radiographic Parameters and Ideal Trans-Fixation Technique for Unstable Syndesmotic Injury with Ankle Fracture

Category: Ankle, Trauma Introduction/Purpose: Anatomical restoration of distal tibiofibular syndesmosis is essential in ankle fractures with syndesmotic injury. However, intraoperative reference line of penetrating angle and evaluation of reduction status remains without consensus. The purpose of this study is to analyze the reduction status of syndesmotic injury using radiographic parameters and to find ideal fixation angle treated with trans-fixation in unstable syndesmotic injury. Methods: Twenty-six patients with ankle fractures with syndesmotic injury that underwent preoperative and postoperative bilateral computed tomography (CT) scans were enrolled. A multi-center study was performed in two tertiary medical centers. All patients were treated with tibiofibular trans-fixation screw or tight rope® fixation. The axial sections of bilateral CT scans were reviewed to measure Fibular Diastasis (FD) and Surface Area of Syndesmosis (SAS) at the level of 1.0 cm above ankle joint. Reduction status was measured by calculating the ratio of postoperative and intact side using radiologic parameters. The trans-fixation angles between the perpendicular line of incisura and distal trans-fixation material was measured. Patients were classified by trans-fixation angle into three groups, as showing 0 -1 degree (A), 1-5 degree (B), 5 or more degree (C) in absolute value. Results: The mean value of reduction status ratio was 1.13 in FD and 1.27 in SAS. The absolute mean value of trans-fixation angle was 4.11°. Trans-fixation angle and reduction status had positive correlation in FD (R = 0.522, p = 0.006) and SAS ratio (R = 0.695, p = 0.000). The absolute mean value of trans-fixation angle in group A, B, C was 0.56° (7 cases), 3.01° (12 cases), and 8.90° (7 cases). The mean value of FD ratio in group A, B, C was 1.01, 1.03 and 1.41. FD and SAS ratio had no difference between group A and B but had significant difference between group A, B and C (p < 0.05). Conclusion: Inappropriate trans-fixation technique had correlated with the loss of reduction after treatment of unstable ankle fracture associated with syndesmotic injury. An angle of 5° from the perpendicular line of the incisura is considered as the ideal trans-fixation angle to maintain the reduction status.

Radiographic Landmarks for Femoral Tunnel Positioning in Lateral Extra-articular Tenodesis Procedures

Background: Lateral extra-articular tenodesis (LET) is being increasingly performed as an additional procedure in both primary and revision anterior cruciate ligament reconstruction in patients with excessive anterolateral rotatory instability. Consistent guidelines for femoral tunnel placement would aid in intraoperative reproducible graft placement and postoperative evaluation of LET procedures. Purpose: To determine radiographic landmarks of a recently described isometric femoral attachment area in LET procedures with reference to consistent radiographic reference lines. Study Design: Descriptive laboratory study. Methods: Ten fresh-frozen cadaveric knees were dissected. The footprints of the lateral femoral epicondyle (LFE) apex and the deep aspects of the iliotibial tract, with its Kaplan fiber attachments (KFAs) on the distal femur, were marked with a 2.5-mm steel ball. True lateral radiographic images were taken. Mean absolute LFE and KFA distances were measured from the posterior cortex line (anterior-posterior direction) and from the perpendicular line intersecting the contact of the posterior femoral condyle (proximal-distal direction), respectively. Furthermore, positions were measured relative to the femur width. Finally, radiographic descriptions of an isometric femoral attachment area were developed. Results: The mean LFE and KFA positions were found to be 4 ± 4 mm posterior and 4 ± 3 mm anterior to the posterior cortex line, and 6 ± 4 mm distal and 20 ± 5 mm proximal to the perpendicular line intersecting the posterior femoral condyle, respectively. The mean LFE and KFA locations, relative to the femur width, were found at –12% and 11% (anterior-posterior) and –17% and 59% (proximal-distal), respectively. Femoral tunnel placement on or posterior to the femoral cortex line and proximal to the posterior femoral condyle within a 10-mm distance ensures that the tunnel remains safely located in the isometric zone. Conclusion: Radiographic landmarks for an isometric femoral tunnel placement in LET procedures were described. Clinical Relevance: These findings may help to intraoperatively guide surgeons for an accurate, reproducible femoral tunnel placement and to reduce the potential risk of tunnel misplacement, as well as to aid in the postoperative evaluation of LET procedures in patients with residual complaints.

Central perpendicular line in macular spectral-domain optical coherence tomography in five eyes

Purpose: The aim of this study is to report a rare spectral-domain optical coherence tomography finding in the macula. Methods: This is a descriptive consecutive case series. Patients diagnosed with hyperreflective central perpendicular line in the macular spectral-domain optical coherence tomography were included. Best-corrected visual acuity assessment, standard Amsler grid test, biomicroscopic examination and macular spectral-domain optical coherence tomography were performed. Results: We examined three men and one woman, aged 56 to 91 years (average age: 75.25 years). Spectral-domain optical coherence tomography showed a hyperreflective central perpendicular line in five eyes accompanied by vitreofoveal adhesion in all of them. In two eyes, we observed a lifting of the ellipsoid zone, and in one eye the external limiting membrane was also pulled. In one eye, a subtle lifting of the interdigitation zone was revealed. In another eye, we also found a triangular foveolar detachment of the interdigitation zone. Snellen’s best-corrected visual acuity ranged from 0.2 to −0.1 logMAR (average of 0.006 logMAR). Amsler grid test was unremarkable in four eyes and metamorphopsia was detected in one eye. One eye developed a full-thickness macular hole several weeks after the phacoemulsification cataract surgery. Conclusion: The presence of a central perpendicular line can be revealed by the macular spectral-domain optical coherence tomography. We hypothesize that this finding could be considered as a sign of vitreomacular traction. In our patients, best-corrected visual acuity was only mildly reduced, and Amsler grid test was affected in only one eye.

Principles of spatial organization and agrarian structure of Ancient Rome

In archaic societies the idea of the spatial organisation was embodied in the cosmogony and was accompanied by a complicated ritual. The Romans embraced the principles of spatial thinking from the Etruscans inherited from them also ritual. In ancient traditions, it is this ritual which have obscured the main ideas on division of space. Reconstruction of the heavenly temple on earth made by the priest largely depended on his individual perception of this task. Adapting the projection of the celestial temple to the spatial division, the Romans gradually began to get rid of the undefined elements of the ritual. Now it was focused on conducting of the principal axes, namely on their orientation towards the four cardinal points. First one held the line designating the East-West, then the perpendicular line North-South. Thus was created the cross of divisors with confined spaces, i.e. coordinate system. The main element of the theory of the Roman spatial division was the limit - a straight line, just held on geographical areas. All limits (main and parallel) precisely defined section of land. In practice, the Roman surveyors carefully spaced and accurately divided areas with limits. These principles are used by the Romans in the organization of the lands in Italy and in the provinces.