Posterior Point Research Articles

Optimal insertion positions of anterior-posterior orientation sacroiliac screw.

To explore the optimal insertion positions of anterior-posterior orientation sacroiliac screw (AP-SIS). Pelvic CT data of 80 healthy adults were employed to measure the anatomical parameters including the insertable ranges of S1 and S2, the length, width and height of the channel with three different horizontal and vertical anterior insertion points starting from the ilium-acetabular recess. To compare pelvic stability by replicating a type C Tile lesions, fifteen synthetic pelvises were fixed with an anterior plate and a posterior AP-SIS employing different anterior insertion points, the whole specimen displacements and shifts in the sacroiliac gap under a cyclic vertical load of 300 N in a biomechanical machine recorded. The posterior and anterior insertable ranges averaged 17.9 × 8.5mm2 and 47.1 × 21.2 mm2, respectively. The channel lengths for three horizontal anterior insertion points gradually decreased from front to back with significant difference (p < 0.05), whereas the width and height for three horizontal anterior insertion points and the parameters for the three vertical anterior insertion points were similar (p > 0.05). The displacements and shifts for three horizontal insertion points gradually increased from front to back (p < 0.05) whereas the measurements involving the three vertical insertion points were similar (p > 0.05). The posterior insertable range is small, where the center between adjacent nerve roots (foramens) is the optimal posterior insertion point. The anterior insertable range is large, where the iliac-acetabular recess is the optimal anterior insertion point for S1 and S2, providing the longest channel and best stability.

Accuracy comparison of bilateral versus complete arch interocclusal registration scans for virtual articulation

Statement of problemAlternatives to the bilateral interocclusal registration scanning technique to improve virtual articulation have not been fully investigated. PurposeThe purpose of this in vitro study was to compare the accuracy of virtually articulating digital casts by using bilateral interocclusal registration scans versus a complete arch interocclusal scan. Material and methodsA set of maxillary and mandibular reference casts were hand-articulated and mounted on an articulator. The mounted reference casts were scanned, and the maxillomandibular relationship record was scanned 15 times using 2 different scanning techniques, the bilateral interocclusal registration scan (BIRS) and complete arch interocclusal registration scan (CIRS), with an intraoral scanner. The generated files were transferred to a virtual articulator, and each set of scanned casts was articulated using BIRS and CIRS. The virtually articulated casts were saved as a set and transferred to a 3-dimensional (3D) analysis program. The scanned casts were set in the same coordinate system as the reference cast and overlaid on top of the reference cast for analysis. Two anterior and 2 posterior points were selected to determine points of comparison between the reference cast and test casts virtually articulated with BIRS and CIRS. The mean discrepancy between the 2 test groups and the anterior and posterior mean discrepancy within each group were tested for significance by using the Mann-Whitney U test (α=.05). ResultsA significant difference was found between the virtual articulation accuracy of BIRS and CIRS (P<.001). The mean deviation for BIRS was 0.053 ±0.051 mm and that for CIRS was 0.265 ±0.241 mm. Furthermore, significant differences were found between the anterior and posterior deviations in both BIRS (P=.020) and CIRS (P<.001). The mean deviation for BIRS was 0.034 ±0.026 mm in the anterior and 0.073 ±0.062 mm in the posterior. The mean deviation for CIRS was 0.146 ±0.108 mm anteriorly and 0.385 ±0.277 mm posteriorly. ConclusionsBIRS was more accurate than CIRS for virtual articulation. Moreover, the alignment accuracy of anterior and posterior sites for both BIRS and CIRS exhibited significant differences, with the anterior alignment exhibiting better accuracy in relation to the reference cast.

Assessment of clinical outcomes after reduction of depressed calcaneal fractures using the push-out molding technique

IntroductionAs minimal invasive techniques for depressed calcaneal fracture treatment have become more common, great progress has been achieved with various surgical methods. While these techniques are still currently utilized, new methods have been developed. This study aimed to report the radiologic and clinical outcomes of depressed calcaneal fracture treatment with the “push-out molding” technique and to propose its clinical utility. Materials and methodsFrom March 2009 to October 2020, a retrospective study was conducted with 52 patients, who received the “push-out molding” technique to treat depressed intra-articular calcaneal fractures (Sanders type II, III, IV). Exclusion criteria were as follows: patients with bilateral calcaneal fractures, open fractures, and a follow-up period <12 months. Radiologic parameters were assessed at following periods: preoperative, postoperative, 3-month follow-up, and last follow-up. Limitation of range of motion (ROM), subjective satisfaction, and complications were assessed at the last follow-up period. Repeated measures ANOVA was used to analyze values at preoperative, postoperative, 3-month, and last follow-up periods. ResultsSignificant differences in the talo-calcaneal angle (p < 0.001), Böhler’s angle (p=<0.001), Gissane’s angle (p = 0.023), distance from the lower cortical border of calcaneus to the anterior (p=<0.001) and posterior (p=<0.001) points of posterior articular surface, calcaneal length (p = 0.019), and talo-calcaneal height (p=<0.001). Postoperatively, the posterior articular surface was well maintained, while 21.2% retained a ROM limitation by 20° or higher. Subjective satisfaction was as follows: excellent (42.3%), good (48.1%), fair (9.6%), and poor (0%). ConclusionThe “push-out molding” is a simple technique with the advantage of not requiring much force to treat depressed calcaneal fractures. It can be used as a beneficial surgical technique with minimal damage to the soft tissue, owing to the reduction from the depressed interior part and less severe ROM limitation.

Surgical Anatomy of Temporalis Muscle Transfer with Fascia Lata Augmentation for the Reanimation of the Paralyzed Face: A Cadaveric Study

Background The temporalis muscle flap transfer with fascia lata augmentation (FLA) is a promising method for smile reconstruction after facial palsy. International literature lacks a detailed anatomical analysis of the temporalis muscle (TPM) combined with fascia lata (FL) augmentation. This study aims to describe the muscle's properties and calculate the length of FL needed to perform the temporalis muscle flap transfer with FLA. Methods Twenty nonembalmed male (m) and female (f) hemifacial cadavers were dissected to investigate the temporalis muscle's anatomy. Results The calculated minimum length of FL needed is 7.03cm (f) and 5.99cm (m). The length of the harvested tendon is 3.16cm/± 1.32cm (f) and 3.18/± 0.73cm (m). The length of the anterior part of the temporalis muscle (aTPM) is 4.16/± 0.80cm (f) and 5.30/± 0.85cm (m). The length of the posterior part (pTPM) is 5.24/± 1.51cm (f) and 6.62/± 1.03cm (m). The length from the most anterior to the most posterior point (aTPMpTPM) is 8.60/± 0.98cm (f) and 10.18/± 0.79cm (m). The length from the most cranial point to the distal tendon (cTPMdT) is 7.90/± 0.43cm (f) and 9.79/± 1.11cm (m). Conclusions This study gives basic information about the temporalis muscle and its anatomy to support existing and future surgical procedures in their performance. The recommended minimum length of FL to perform a temporalis muscle transfer with FLA is 7.03cm for female and 5.99cm for male, and minimum width of 3 cm. We recommend harvesting some extra centimeters to allow adjusting afterward.

GlottisNetV2: Temporal Glottal Midline Detection Using Deep Convolutional Neural Networks.

High-speed videoendoscopy is a major tool for quantitative laryngology. Glottis segmentation and glottal midline detection are crucial for computing vocal fold-specific, quantitative parameters. However, fully automated solutions show limited clinical applicability. Especially unbiased glottal midline detection remains a challenging problem. We developed a multitask deep neural network for glottis segmentation and glottal midline detection. We used techniques from pose estimation to estimate the anterior and posterior points in endoscopy images. Neural networks were set up in TensorFlow/Keras and trained and evaluated with the BAGLS dataset. We found that a dual decoder deep neural network termed GlottisNetV2 outperforms the previously proposed GlottisNet in terms of MAPE on the test dataset (1.85% to 6.3%) while converging faster. Using various hyperparameter tunings, we allow fast and directed training. Using temporal variant data on an additional data set designed for this task, we can improve the median prediction accuracy from 2.1% to 1.76% when using 12 consecutive frames and additional temporal filtering. We found that temporal glottal midline detection using a dual decoder architecture together with keypoint estimation allows accurate midline prediction. We show that our proposed architecture allows stable and reliable glottal midline predictions ready for clinical use and analysis of symmetry measures.

Late-term cardiac magnetic resonance imaging in multisystem inflammatory syndrome in children

Background. Cardiac involvement in multisystem inflammatory syndrome in children may have a spectrum ranging from mild disease to severe heart failure due to fulminant myocarditis. Cardiac involvement usually resolves after clinical recovery. However, the adverse effects of myocarditis on cardiac function after recovery are not fully known. This study aims to investigate cardiac involvement by performing cardiac magnetic resonance imaging (MRI) after the acute and recovery periods. Methods. 21 patients with clinical and laboratory signs of myocarditis, including left ventricular systolic dysfunction, mitral regurgitation, elevated troponin T, elevated N-terminal pro-B-type natriuretic peptide and electrocardiographic changes, who had given consent for cardiac MRI, underwent cardiac MRI after completion of the acute and recovery phases. Results. When compared to 16 patients with normal cardiac MRI, five patients with cardiac fibrosis on MRI were older, had greater body mass indexes, lower leucocyte counts, lower neutrophil counts, higher blood urea nitrogen levels and higher creatinine levels. Cardiac fibrosis on MRI was located in the posterior right ventricle insertion point and in mid ventricular septum. Conclusions. Adolescence and obesity appear as risk factors for the development of fibrosis as a late-term sequela of myocarditis. Furthermore, future studies reporting the follow-up data of patients with fibrosis are necessary to predict and manage adverse outcomes.

Feasibility of safe posterior C1–2 transarticular screw fixation: CT morphometric study

Background. C1–2 transarticular fixation according to the F. Magerl technique is one of the most reliable methods of C1–2 screw stabilization. An important aspect of the precise placement of implants during transarticular fixation under X‑ray control is the use of correct selection of start‑ and end‑points of the installation trajectory. At certain values of the height and width of C2 isthmus some screw installation trajectories may be accompanied by a zero probability of vertebral artery damage that might be due to the screw malposition.Aim. To evaluate CT morphometric characteristics of the C2 vertebra to assess the possibility of safe C1–2 transarticular fixation.Materials and methods. The analysis performed was based on the data obtained from 7672 patients having admitted with suspected injury to the N.V. Sklifosovsky Research Institute of Emergency Medicine during the period from 01.01.2019 to 31.07.2019. The study involved 6 neurosurgeons and 6 medical doctors of the X‑ray diagnostics department. The measurements were carried out in 2 stages. Each parameter (isthmus height – IsthH, isthmus width – IsthW, lateral mass height – LmH) was measured 2 times. In case of high intraclass correlation, the mean value of the measurements was calculated, which was included in the final analysis.Results. The intraclass correlation coefficient for all measurements approached an excellent correlation values and was 0.852 (95 % CI 0.844–0.860). Morphometric characteristics were calculated basing on data from 795 patients. The IsthH value was 7.45 ± 1.66, IsthW – 8.56 ± 1.48, LmH – 5.56 ± 1.84 mm. In men, the transarticular fixation was significantly more likely to be performed without injury of the vertebral artery (in 66.1 % of cases; χ2‑test, p &lt;0.000001), whereas in women – only in 29.9 % of cases.Conclusions. The results obtained suggest that percutaneous bilateral transarticular fixation with the use of posterior spinolaminar point and middle of the atlas anterior arch as landmarks potentially serves as a method of choice in 88.3 % of patients. Of all patients with normal anatomy of C2 isthmus, men are twice more likely to undergo transarticular fixation without damage of vertebral artery than women, the probability exceeds 66 %. However, the risk of injury of this blood vessel in other patients does not exceed 2.3 %, which is comparable with outcomes of other methods of C1–2 screw stabilization.

Safe drilling zones for anteriorly, central, and posteriorly angulated syndesmotic stabilization devices

PurposeThe purposes of the study were to (1) analyze the shape of the distal fibula at the location of syndesmotic stabilization and to (2) define safe zones at the distal-lateral fibula for three different drilling tunnel orientations: anteriorly-, posteriorly angulated and center-center.MethodsPostoperative, bilateral CT images of adult patients that underwent syndesmotic stabilization (suture-button system) for an acute, unilateral ankle injury were analyzed. Manual axial CT reconstructions of the uninjured side were generated. First, the axial shape of the distal fibula was classified. The aspect ratio between the anterio-lateral and the posterior-lateral surfaces of the fibula was calculated to assess symmetry. Second, the same axial planes were used to define the safe zones. Each drilling-tunnel orientation (anterior, central, posterior) comprised a fixed medial tibial anchor point and a safe zone on the lateral fibula. For each of the three orientations, the most anteriorly and posteriorly drilling tunnel location was simulated. Next to a cumulative visual analysis, a quantitative analysis of the most anterior and posterior point on the anterio- and posterior-lateral surfaces was calculated.ResultsA total of 96 CT datasets were analyzed. (1) 81% of fibulae revealed a triangular convex-, 10% an irregular-, and 8% a quadrilateral shape. The lateral surface ratio was 1.0 ± 0.2 (range: 0.7–1.5), not differing between the fibula types (n.s.). (2) The safe corridor on the lateral surface of the fibula for an anteriorly angulated drilling tunnel was − 8% to − 41%, for a posteriorly angulated drilling tunnel was 0% to 46%, and for a center-center alignment − 7 ± 11% (range: − 28 to 18%).ConclusionThe meta-diaphyseal region of the distal fibula revealed a homogeneous crosssectional shape. The lateral apex of the fibula can serve as a landmark defining safe zones to place the drilling tunnels correctly. Applying these safe zones in clinical practice could help to avoid the misplacement of the syndesmotic fixation device.Level of evidenceLevel III, retrospective radiographic study.

Thickness of the Deltoid Muscle and Location of the Anterior Branch of the Axillary Nerve and the Posterior Circumflex Humeral Artery for Deltoid Injections.

This study investigated the thickness of the deltoid muscle and the location of the anterior branch of the axillary nerve (AAN) and posterior circumflex humeral artery (PCHA), with the goal of maximizing the effectiveness of deltoid injections. Forty specimens from 22 adult Korean cadavers were used. A reference line was identified, connecting the anterior point of the deltoid muscle (AP) and the posterior point of the deltoid muscle (PP) on the surface. The midpoint between the AP and PP was used as the origin point (OP). The line connecting the OP and the lowest point of the deltoid tuberosity (DP) was used as the y-axis. The mean distance of the reference line from the AP to PP was 4.7 ± 0.7 cm. The vertical mean length of the deltoid muscle from the OP and DP was 16.1 ± 1.0 cm. At the 3, 5, and 7 cm sites, the thickness of the deltoid muscle was 0.62 ± 0.9, 0.73 ± 0.7, and 1.3 ± 1.1 cm, respectively. Most of the branches of the axillary nerve were concentrated in the third section (4-6 cm, 51%), while the branches of the PCHA were predominantly found in the fourth section (6-8 cm, 69%). The peripheral branches of the AAN entering the muscle were distributed between 2.2 and 9.8 cm from the acromion. The mean number of the peripheral branches of the AAN was 9.6 ± 3.4. In the deltoid muscle, the mean number of peripheral branches of the PCHA was 8.2 ± 2.8. Administering deltoid injections 5-6 cm below the OP is recommended to avoid axillary nerve injury.

Medial meniscus posterior root tear reconstructed with gracilis autograft improve healing rate and patient reported outcome measures

BackgroundMany surgeries have not reversed or prevented progressive symptomatic knee arthritis, and there is no consensus regarding the ideal repair or reconstruction technique for meniscal root treatment. Additionally, there is a lack of studies comparing the clinical efficacy evaluation of different repair techniques. The aim of the present study is to compare the clinical efficacy and healing rates of meniscus root in the treatment of medial meniscus posterior root tear (MMPRT) with the arthroscopically assisted meniscus root reconstruction with gracilis autograft and transtibial pull-out technique.MethodsPatients with MMPRT (type II) who received treatment of posterior meniscus root attachment point through the tibial tunnel between January 2018 and April 2019 were included in this study. Patients were divided into 2 groups (arthroscopically assisted gracilis autograft reconstruction technique: 29 cases; transtibial pull-out technique group: 35 cases) according to the different treatment methods. The mean follow-up period was 26.9 ± 2.3 months. The demographics, functional recovery of the knee, and meniscus root healing rates (assessed using knee magnetic resonance imaging (MRI) at the final follow-up) were compared between the two groups.ResultsThere was a statistically significant improvement in the Lysholm score, international knee documentation committee (IKDC) score, and visual analogue scale (VAS) score (P < 0.001 in both groups). Additionally, compared with the transtibial pull-out repair group, the arthroscopically assisted reconstruction with gracilis autograft showed significant improvement in the meniscus root healing rates, Lysholm score, and IKDC score at the end of follow-up (P < 0.05).ConclusionsCompared with the transtibial pull-out technique, the arthroscopically assisted meniscus root reconstruction with gracilis autograft was advantageous for treating these patients with superior clinical outcome and higher meniscus root healing rates.Level of evidenceLevel III.

Comparison of accuracy in digital and conventional cross-mounting

Statement of problemThe use of digital interocclusal registration scans for virtual articulation and mounting has been studied extensively; however, the accuracy of the cross-mounting procedures in a digital workflow is not well understood. PurposeThe purpose of this in vitro study was to compare the accuracy of digital and conventional cross-mounting by measuring the 3-dimensional deviation at each step of sequential cross-mounting. Material and methodsA set of reference casts and complete arch interim restorations was prepared for complete arch complete-coverage restorations, hand-articulated, and mounted in an articulator. The reference casts were then scanned with and without the interim restorations to generate 4 reference casts for cross-mounting. For the conventional group, 15 sets of the 4 casts were printed. Polyvinyl siloxane interocclusal registration records were made of the reference casts for each set, and casts were sequentially cross-mounted. For the digital workflow, 15 sets of bilateral interocclusal registration scans were made of the mounted reference casts and used to align the cast scans. Three-dimensional deviations at 2 anterior and 2 posterior points were recorded between the experimental mountings and the reference casts on each set of casts. Nonpaired t test and analysis of variance (ANOVA) were used to compare the average discrepancy between the 2 groups, and the pooled anterior versus posterior discrepancies were compared (α=.05). ResultsA significant difference was found between conventional and digital cross-mounting procedures (P<.001), but no significant difference was found in either group, conventional (P=.116) or digital (P=.987), at each step of the sequential mountings. The mean ±standard deviation at the final set of related casts in the conventional workflow was 201.6 ±137.0 μm and that in the digital group was 50.3 ±47.5 μm, with a significant difference between anterior and posterior deviations in the digital group (P=.028), but not in the conventional group (P=.143). The mean ±standard deviation anterior conventional deviation was 175.6 ±119.2 μm and that in the digital group was 36.9 ±30.9 μm. The mean ±standard deviation posterior conventional deviation was 227.6 ±50.2 μm and that in the digital group was 63.7 ±57.2 μm. ConclusionsDigital cross-mounting was more accurate than conventional cross-mounting, although increased deviation was found in the anterior region compared with the posterior region.

Determination of the Entry Point for Lower Lumbar Intradiscal Procedure Using Transforaminal Technique: Cross-Sectional Study Using Magnetic Resonance Imaging.

Triangular working area otherwise known as the Kambin triangle is designated as a safe place to position the instrument during the operation, with minimal risk to exiting nerves. This study aims to improve understanding and increase the safety of various transforaminal intradiscal procedures at L3/L4, L4/L5, and L5/S1 levels. A cross-sectional analysis involving 102 MRIs that met the inclusion criteria was obtained and analyzed at the L3/L4, L4/L5, and L5/S1 discs level. For each level, the Kambin triangle was measured. By evaluating those measurements, the viability of this method was determined. Safe working zone approach angles were consistently getting wider from L3 to S1 levels. It was statistically significant to be wider for the left side for the mean angle of lateral nucleus trajectory at the L4/L5 level and L5/S1. The entry point is at 32, 45, and 55-60 mm from the midline, and the instrument should be directed at 12°, 20°, and 27° medially for the lateral nucleus at L3/L4, L4/L5, and L5/S1, respectively. The center of the nucleus pulposus entry point is at 64, 77, and 85 mm from the midline with a medial inclination of 40°, 47°, and 52°, respectively, for L3/L4, L4/L5, and L5/S1. For the posterior nucleus pulposus, the skin should be pierced 90, 140, and 180 mm from the midline and directed medially at 53°, 61°, and 68°, respectively, for L3/L4, L4/L5, and L5/S1. The posterior annulus fibrosis entry point is 172, 355, and 450 mm with a medial inclination of 69°, 80°, and 84° at L3/L4, L4/L5, and L5/S1, respectively. The sagittal inclination is 3° cephalad at L3/L4, 10° caudally at L4/L5, and 27° caudally at L5/S1. Preoperative MRI assessment is important to determine the angle of trajectory for the safe entry point for intradiscal procedure via transforaminal approach.

Novel Three-Holed Titanium Plate Fixation during Open Door Laminoplasty for Cervical Spondylotic Myelopathy: Comparison with Conventional Titanium Plate.

For reconstructing the posterior cervical muscular-ligament complex, attachment points and various modified techniques were designed and applied in clinical practice. This study investigated the clinical and radiographic outcomes of open door laminoplasty with modified centerpiece mini-plate fixation and extensor attachment point reconstruction in the treatment of cervical spondylotic myelopathy (CSM). Sixty-nine patients with CSM who underwent C3-C7 open door laminoplasty at our hospital from January 2016 to May 2018 were divided into two groups: 37 and 32 patients underwent laminoplasty with modified and conventional centerpiece titanium plate fixation (MPF and CPF groups), respectively. Changes in cervical spinal angle (CSA), cervical range of motion (ROM), posterior cervical muscle atrophy, neurological function (Japanese Orthopaedic Association [JOA] score), Neck Disability Index (NDI), and axial symptom severity were compared between the two groups. There were no significant differences in operative duration (136.7± 23.9 vs 128.3± 21.5 min, t=1.525, p > 0.05), volume of intraoperative blood loss (275.9± 33.1 vs 268.2± 31.6ml, t=0.984, p > 0.05), lamina open angle (41.2° ± 4.5° vs 39.4° ± 4.1°, t=1.726, p > 0.05), and spinal cord drift distance (2.4± 0.3 vs 2.3± 0.4 mm, t=1.184, p > 0.05) between the two groups. After surgery, JOA score significantly increased (p < 0.05), and neurological recovery rates were similar (62.7% vs 63.4%, t=0.208, p > 0.05). The NDI score was significantly decreased in both the groups (p< 0.05); however, the MPF group recovered to a greater degree than the CPF group (8.3± 1.2 vs 9.8± 1.4) (t=4.793, p< 0.05). There was no significant change in cervical ROM postoperatively compared with preoperatively in either group (p > 0.05). CSA decreased from 21.7° ± 2.8° to 18.3° ± 2.1°, and posterior cervical muscle cross-sectional area decreased from 35.2± 4.9 cm2 to 31.0 ± 4.1 cm2 in the CPF group (p < 0.05), but no significant change was observed in the MPF group (20.6° ± 2.5° to 20.4° ± 2.6°and 35.9± 5.1 to 34.1± 4.6 cm2 , respectively) (p> 0.05). Postoperative axial symptom severity was significantly worse in the CPF group than in the MPF group (Z=-2.357, p < 0.05). As an improvement to the conventional titanium plate, the modified centerpiece titanium plate effectively provides an attachment point for the posterior muscle-ligament complex, reducing posterior cervical muscle atrophy and improving neck function, without inflicting additional surgical trauma.

A szemnyomás változásának hatása a szaruhártya és a szem törőerejére a Liou–Brennan-modellszem alapján

It is a clinical experience that with significantly higher intraocular pressure, glass ordering may be inaccurate, therefore, it should be performed after adjustment of intraocular pressure. To analyze the effect of intraocular pressure on the refractive power of the cornea and of the eye, using geometrical properties of the Liou-Brennan model eye and finite element modeling. Using corneal parameters of the Liou-Brennan model eye, a parametric geometrical model and with these data finite element modelling, using the Ansys (Ansys, Canonsburg, PA, USA) program, has been performed. Corneal tissue properties have been defined based on trilinear material model of Wollensak and boundary conditions based on Pandolfi. The effect of changes in intraocular pressure on geometrical corneal properties with optical impact (corneal curvature at the anterior and posterior corneal surface at the optical center and axial displacement of the anterior and posterior corneal surface points at the optical center) have been analyzed. Based on the geometric characteristics obtained, using the paraxial ray tracing method, changes in the optical properties of the cornea and the eye have been calculated. With increasing intraocular pressure load, anterior and posterior central corneal radius of curvature decreased and corneal surface points at the optical center at the anterior and posterior surface moved forwards, the cornea thinned. Axial displacement of corneal volume points was maximal for all pressure load values at the optical center of the posterior corneal surface. The refractive power of the cornea decreased as eye pressure increased, while the refractive power of the entire eye increased. We verified using the Liou-Brennan model eye and finite element modelling that a change of the intraocular pressure load between 10 and 30 mmHg may result in 0.31-0.86 mm decrease of the corneal radius of curvature, in 1.5-4.8 D increase in the keratometric values and in about 1.2-3.9 D increase in the total optical power of the eye. A decrease of 0.14 D to 0.69 D has been measured in the corneal optical power in the examined eye pressure range. Orv Hetil. 2022; 163(47): 1872-1879.

The placement of percutaneous retrograde acetabular posterior column screw based on imaging anatomical study of acetabular posterior column corridor

ObjectiveTo explore the entry point, orientation, and fixation range of retrograde acetabular posterior column screw.MethodThe computed tomography data of 100 normal adult pelvises (50 males and 50 females, respectively) were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabular posterior column was carried out orienting from ischial tuberosity to iliac fossa in the Mimics software. Virtual screw was inserted perpendicular to the transverse section of acetabular posterior column corridor, and the maximum screw diameter, entry point, orientation, exit point were measured. The screw fixation range, the easy-to-penetrate sites, and intraoperative optimal fluoroscopic views were assessed.ResultsThe acetabular posterior column corridor showed a triangular-prism shape. The virtual screw entry point was located at the midline between the medial and lateral edges of the ischial tuberosity. The distance between the entry point and the distal ischial tuberosity was around 13 mm. The distances between the exit point and the true pelvis rim, and ipsilateral anterior sacroiliac joint line were (19.33 ± 2.60) mm and (23.65 ± 2.42) mm in males, respectively. As for females, those two data were (17.63 ± 2.00) mm and (24.94 ± 2.39) mm, respectively. The maximum diameters of screws were (17.21 ± 1.41) mm in males and (15.54 ± 1.51) mm in females. The angle between the retrograde posterior column screw and the sagittal plane was lateral inclination (10.52 ± 3.04)° in males, and that was lateral inclination (7.72 ± 2.99)° in females. Correspondingly, the angle between the screw and the coronal plane was anterior inclination (15.00 ± 4.92)° in males, and that was anterior inclination (12.94 ± 4.72)° in females. Retrograde acetabular posterior column screw through ischial tuberosity can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center. The easy-to-penetrate sites were located at the transition between the posterior acetabular wall and the ischium, the middle of the acetabulum, and 1 cm below the greater sciatic notch, respectively. The iliac oblique 10°, iliac oblique 60°, and obturator oblique 60° views were the intraoperative optimal fluoroscopic views to assess whether the screw was safely inserted.ConclusionRetrograde acetabular posterior column screw entry point is located at the midline between the medial and lateral edges of the ischial tuberosity, which is 1.3 cm far from the distal ischial tuberosity. The screw direction is about 10° lateral inclination and 15° anterior inclination, which can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center.

The relationship between frontal sinus dimensions and skeletal malocclusion.

The aim of this retrospective research is to compare frontal sinus dimensions in skeletal Class I, skeletal Class II, and skeletal Class III individuals and to evaluate the relationship of these dimensions with anterior skull base length and some cephalometric values. In this research, we used lateral cephalometric radiographs of 60 people aged 17 to 25. In individuals with skeletal Class I malocclusion, skeletal Class II malocclusion due to mandibular insufficiency, and skeletal Class III malocclusion due to mandibular excess, measurements of frontal sinus length and height as well as S-N, Co-A and Co- Gn lengths, ANB0, FMA0, SN-GoGn0 angles values were performed. The length between the highest point and the lowest point of the frontal sinus was calculated as the height of the frontal sinus, and the length between the most anterior and the most posterior points of the frontal sinus was calculated as the length of the frontal sinus. The frontal sinus length and height were found to be higher in skeletal Class III individuals than in skeletal Class I and skeletal Class II individuals, however, there was no significant difference between skeletal Class I and Class II individuals. The increase in frontal sinus height and length correlated positively with the decrease in the ANB angle and the increase in the SN and Co-Gn lengths. The dimensions of the frontal sinus may be an indicator for the remaining mandibular growth potential.

Convex–concave and anterior–posterior spinal length discrepancies in adolescent idiopathic scoliosis with major right thoracic curves versus matched controls

PurposeThe apical deformation in adolescent idiopathic scoliosis (AIS) is a combination of rotation, coronal deviation and passive anterior lengthening of the spine. In AIS surgery, posterior–concave lengthening or anterior–convex shortening can be part of the corrective maneuver, as determined by the individual surgeon’s technique. The magnitude of convex–concave and anterior–posterior length discrepancies, and how this needs to be modified to restore optimal spinal harmony, remains unknown.MethodsCT-scans of 80 pre-operative AIS patients with right convex primary thoracic curves were sex- and age-matched to 80 healthy controls. The spinal length parameters of the main thoracic curves were compared to corresponding levels in controls. Vertebral body endplates and posterior elements were semi-automatically segmented to determine the length of the concave and convex side of the anterior column and along the posterior pedicle screw entry points while taking the 3D-orientation of each individual vertebra into account.ResultsThe main thoracic curves showed anterior lengthening with a mean anterior–posterior length discrepancy of + 3 ± 6%, compared to a kyphosis of − 6 ± 3% in controls (p < 0.01). In AIS, the convex side was 20 ± 7% longer than concave (0 ± 1% in controls; p < 0.01). The anterior and posterior concavity were 7 and 22 mm shorter, respectively, while the anterior and posterior convexity were 21 and 8 mm longer compared to the controls.ConclusionsIn thoracic AIS, the concave shortening is more excessive than the convex lengthening. To restore spinal harmony, the posterior concavity should be elongated while allowing for some shortening of the posterior convexity.

Localization of the nerves innervating the pelvic floor muscles: An application to pelvic pain treatment.

The aim of this study was to achieve accurate localization of the body surface position and depth of the center of the intramuscular nerve dense region (CINDR) of the pelvic floor muscles and to establish a target site for treating pelvic floor muscle spasm or weakness. Thirty-six adult cadavers were studied in the prone position. To locate the CINDR of the levator ani and coccygeus muscles, horizontal (H) and longitudinal (L) reference lines were used. Sihler's staining revealed the intramuscular nerve dense region of the pelvic floor muscles. The CINDR was labeled with barium sulfate and spiral computed tomography scanning, and three-dimensional reconstructions were obtained. The anterior and posterior CINDR projection points (P and P'), the position of point P projected on to the H and L lines (PH and PL ), and the CINDR depth were determined using the Syngo system. The PH of the CINDR of the levator ani and the coccygeus muscle were located at (24.73 ± 0.17)% and (15.93 ± 0.31)% of the H line, respectively. The PL were located at (84.30 ± 2.47)% and (6.76 ± 0.93)% of the L line. The puncture depth of the levator ani muscle was located at (5.56 ± 0.53) cm, and the depth of the coccygeus muscle at (22.08 ± 2.11)% of the PP' line. The body surface position and depth of the CINDR of the pelvic floor muscles were conducive to locating the target more efficiently and enhancing the efficacy of botulinum toxin A injection for treating pelvic floor muscle spasm and weakness with electrical stimulation or biofeedback.

Frequency of Parallelism of Occlusal Plane to ALA-Tragus Line in Different age Groups: A Photographic Study

Background: For the complete dentures to look, sound, fit, and feel their best, it is crucial that the occlusal plane be positioned correctly. There are a number of different anatomical landmarks that have been proposed to arbitrate the position of the occlusal plane, with the Ala-tragus line being the most commonly adopted by the professions. Purpose: To ascertain the effect of age on location of Ala-Tragus line. Materials and methods: One hundred and seventy six patients (128 males and 48 females) having complete dentition were recruited in the study, and grouped according to their age. Patients' right lateral profiles were photographed after they had positioned the fox plane intraorally so that it was parallel to the occlusal plane. Images were taken with Canon camera model no. EOS 700 D with a resolution power of 18.0 Mega pixels, images produced were transferred to computer and traced using computer software AutoCAD 2014 and angle between Fox plane and superior, Middle and inferior borders of Ala-tragus and angle measured between three different lines. Data obtained was statistically analyzed using Pearson chi-square test. Results: There was a statistically significant relationship between age and Ala-Tragus line height. When the middle tragal border was used as the posterior reference point in the analysis, the occlusal plane was also shown to be more parallel to the Ala-tragus line age groups A, C, and D, being 42.0% (74/176). The second common location was the superior line in age groups B and D, being 36.9% (65/176), and the least common location was found to be the inferior line in almost all age groups, being 21.0% (37/176). Conclusion: Within the limitations of this study, it can be concluded that a definite relationship exists in between age and level of Ala-tragus line. Keywords: Ala-tragus line, interpupillary line, occlusal plane

Signs and Symptoms of Temporomandibular Dysfunction and Radiographic Condylar Morphology in Patients with Idiopathic Condylar Resorption.

Background: Little is known about the clinical characteristics of idiopathic condylar resorption (ICR). The aim of this study was to examine the signs and symptoms of temporomandibular dysfunction (TMD) and evaluate the morphological characteristics of the condyles in patients with ICR. Methods: Sixty patients with ICR (41 in the bilateral ICR group and 19 in the unilateral ICR group) and forty-one healthy controls were examined. Signs and symptoms of TMD were described, and three-dimensional models of the condyles were measured and analyzed. Results: In total, 81.7% of ICR patients had self-reported symptoms and 78.3% of ICR patients had objective-found signs. The anteroposterior diameter, transverse diameter, height, maximal sectional area, volume of the condyles, axial angle, and the distance from the posterior point of the condyle to the Saggittal standard line were significantly smaller in the ICR condyles compared with the controls (p < 0.05). The condylar neck angle was significantly larger in the ICR condyles compared with the controls (p < 0.05). Conclusions: Most patients with ICR had signs and symptoms of TMD. The prevalence of clicking and opening–closing deviation was significantly different between the bilateral and the unilateral ICR groups. In patients with ICR, the size of the condyles decreased significantly; the condyles also rotated inward, moved forward, and inclined posteriorly.