Ideal Entry Research Articles

The C2 Cortical Screw, an Alternative Fixation Technique for the C2 Segment During High Cervical Spine Surgery: Technical Note

For posterior fixation of C2 vertebra (the axis), several fixation techniques such as pedicle screw, laminar screw, and pars screw have been reported. A pedicle screw (PS) is considered the strongest among the techniques, but certain situations make PS fixation impossible or difficult. These include patients with a narrow C2 pedicle or high-riding vertebral artery. We introduced an alternative screw technique for C2 that addressed the aforementioned problems with safely placing it, which we termed a cortical screw (CS) for C2. Among a total of 28 cases using C2 CS for high cervical spine surgery, 2 cases using C2 CS were described. One patient was a 76-year old woman with a gait disturbance and myelopathic symptoms and diagnosed with C1-C2 myelopathy and translational instability. The other case was 54-year old man with posterior neck pain after traffic accident and diagnosed with C1-C2 fracture-dislocation. We used the C2 CS as an alternative technique for high cervical spine surgery in these patients and describe the ideal entry point and trajectory. A postoperative computed tomography scan confirmed proper positioning of the C1 posterior arch screw and C2 CS, with satisfactory reduction of the C2 dens and adequate restoration of the C1-C2 spinal canal. The patient experienced no screw-related postoperative complications, and postoperative 1-year computed tomography images showed that solid union and good alignment of C1-2 segment was achieved. C2 CS can be suitable alternative for C2 screw fixation technique in posterior high cervical spine fusion surgery.

Predicting the Ideal Ventricular Freehand Pass Trajectory Using Osirix Software and the Role of Occipital Shape Variations

Cannulation of lateral ventricles via a posterior approach is a common neurosurgical procedure. It is often believed that a single entry and fiducial point applies to all. No importance is given to skull shape variations, which can lead to wrong shunt positions and revisions. A virtual-reality study was conducted to find the ideal entry point, ideal forehead fiducial point, and ideal angulation of the ventricular catheter and variations in these with changes in skull shapes. Fifty human cadaveric skulls were used to measure anteroposterior (AP) diameter and width and to classify shape of skulls into 4 types. Hydrocephalus (100 cases) and normal magnetic resonance images (50 cases) were studied from a PACS (Picture Archiving and Communication System) database. An Osirix DICOM Viewer (3.9.4) was used to reconstruct the images and estimate the ideal, 90°, and midline shunt trajectory and correlate the same with AP/width ratios and skull shapes. Contrary to popular practice, the vertical distance from the inion for ideal trajectory placement was <6 cm and >4 cm in all shapes and ratio groups for hydrocephalus and nonhydrocephalus cases, respectively. As the AP/width ratio increases, the fiducial needs to be placed at a higher distance from the nasion and the distance of the entry point also increased from the inion. A rounder or more dolichocephalic skull dictates a 90° approach to be better, especially as the first pass. No magical external entry point uniformly applicable for all cases exists. Hence, there is a need to classify skulls according to shapes/ratios and to use a tailored approach for a freehand pass to cannulate the ventricles.

Frame-Based Stereotactic Endoscopic Third Ventriculostomy—Toward Improved Precision and Minimizing Morbidities

Endoscopic third ventriculostomy (ETV) is a widely accepted treatment for obstructive hydrocephalus. For most practitioners, this procedure will be performed without navigation guidance. Without such guidance, the complications associated with the procedure have ranged from 1% to 8%. We hypothesized that the discrepancy between the surface bony anatomy and internal cranial anatomy contributes to the morbidities associated with ETV. We tested this hypothesis by comparing the position of the entry point defined by the classic Kocher's point relative to the ideal entry point that would result in no manipulation of the endoscope defined by frame-based stereotaxis. The cranial computed tomography scan of 58patients who had undergone frame-based stereotactic ETV was reformatted into 3-dimensional renderings. The location of this entry point was compared with the Kocher point, as determined by the external bony anatomy. Overall, >70% of the burr holes that provided an ideal trajectory to the third ventricle were ≥0.5 cm from the Kocher point in both the sagittal and the coronal planes. Median deviations of 0.74 and 0.81 cm in the coronal (P < 0.01) and sagittal (P < 0.0001) planes were observed. The use of stereotactic endoscopic techniques increase the safety of third ventriculostomy by adding precision and reducing otherwise unnecessary surgical maneuvering.

A novel tube technique enables visualization of the anatomy of the facet joints and accurate placement of the Jamshidi needles with low radiation exposure: Technical note

BackgroundPercutaneous pedicle screws(PPS) have been used for decades. The difficult part of PPS placement is locating the proper entry sites on the facet joints for the Jamshidi needles. The correct positioning is usually ensured by fluoroscopy, which exposes surgeons and patients to extensive radiation exposure. ObjectiveTo describe a novel retractor tube technique used in the placement of PPS, which enables visualization of the anatomy of the facet joints and enables accurate placement of the Jamshidi needles. MethodsA newly designed 15-mm-diameter retractor tube was applied during the placement of Jamshidi needles in 21 operations using PPS to treat thoracolumbar fracture. The anatomy of the entry site could be clearly visualized, and a Kirschner wire was inserted 2 mm into each of the ideal entry sites. When all the Kirschner wires were placed, the annular tubes of the Jamshidi needles were placed along the Kirschner wires into the pedicles. Fluoroscopy was used to confirm the positions of the Jamshidi needles. The rest of the procedure was conducted in the traditional PPS placement technique. ResultsThe entrance sites were successfully accessed through the retractor tube, with only one adjustment needed at most. Only one or two fluoroscopy images were taken during the placement of the Kirschner wires, and another image was taken after all the Jamshidi needles were placed. Fluoroscopy confirmed that the positioning of the PPS was good. ConclusionA retractor tube accurately exposes the entry points on the facet joints in PPS placement, and is technically easy to use.

Radiographic Evaluation of the Tibial Intramedullary Nail Entry Point.

Tibia fractures are common injuries that can often be effectively treated with intramedullary nail (IMN) fixation. The ideal starting point for IMN reaming and nail placement is well described and regarded as a crucial aspect in the technique. The purpose of this study is to determine the accuracy and precision with which the starting point is established and if this is maintained after nail insertion during fracture fixation. Fifty consecutive tibia fractures treated by IMN fixation sized 9 to 13 mm through an infrapatellar or medial parapatellar approach and 50 treated with a suprapatellar approach were evaluated. The starting point for reaming and IMN placement was measured using intraoperative fluoroscopy. Postoperative radiographs were used to determine the center of the IMN after placement. The distance between the measured points and the ideal starting point was measured. Deviation from the ideal entry point on intraoperative fluoroscopy averaged 4.6 ± 4.0 mm medially, 2.9 ± 3.7 mm anteriorly, and 2.7 ± 3.3 mm distally. In 30% of cases, the final IMN position varied from the entry point by greater than one SD in the coronal or sagittal plane. No difference between approaches was appreciated. Although the ideal starting point for tibial IMN fixation is known, this is frequently not the starting point accepted in practice. Final position of the IMN is independent of IMN size or approach and is not markedly different than the obtained starting point. Therapeutic level III.

The entry point of intramedullary tibia cutting guide should vary according to the individual tibia morphology in TKA.

In total knee arthroplasty (TKA) using the intramedullary tibial cutting guide (IMTCG), the positioning of the IMTCG is important for accurate tibial bone resection. The aim of this study was to evaluate the ideal entry point of IMTCG and affecting radiologic factors. From May 2017 to February 2018, 91 consecutive TKAs for osteoarthritis were included. From preoperative full-length radiographs, we measured the medial proximal tibia angle (MPTA), lateral distal tibia angle (LDTA), tibial bowing angle (TBA), medial to lateral width of the tibial plateau, tibial length, and ideal coronal entry point. In preoperative short knee lateral radiographs, we measured the anterior to posterior length of the tibial plateau, tibial posterior slope angle (TPSA), metaphysio-diaphyseal angle (MDA), and ideal sagittal entry point. The ideal coronal and sagittal entry points were defined as the points crossing the tibial plateau and tibial anatomical axis on the coronal and sagittal radiographs, respectively. The ideal entry point was 51.4 ± 4.3% (SD) from the medial margin and 27.0 ± 5.8% (SD) from the anterior margin of the tibial plateau. However, the range varied from 39.8 to 60.5% on the coronal plane and from 9.6 to 37.7% on the sagittal plane, respectively. As the MPTA (rho = -0.490) and TBA (rho = -0.433) were increased, the coronal entry point moved medially. As TPSA (rho = -0.761) and MDA (rho = -0.495) were increased, the sagittal entry point moved anteriorly. The ideal entry point of IMTCG should vary according to the individual tibial morphology.

Anterior Atlantooccipital Transarticular Screw Fixation: A Cadaveric Study and Description of a Novel Technique.

Retrospective analysis of collected data and operative experiment on human cadavers. To describe a novel technique of the anterior atlantooccipital (AC) transarticular screw fixation, and to analyze the pertinent anatomy with cadaveric and radiographic assessment of the feasibility, safety, and general applicability of this technique. In some situations, the posterior AC fixation techniques may not be possible, or may require supplemental fixation, which include the congenital hypoplasia, absence of the bony elements, and even revision surgery. However, an anterior screw fixation technique may add stability to further attempts at obtaining an arthrodesis. A detailed description of the surgical technique was presented. Three-dimensional (3D) CT reconstruction of the cranioverteral region of 30 patients were performed to determine screw entry points, target points, and proposed screw trajectories. Following screw insertion in eight fresh frozen human cadaver spine specimens, dissection verified screw location relative to structures at risk. The ideal entry point is located caudal to the C1 superior facet joint in line with the medial third of the C1 superior facet. The ideal screw is directed 41.7° posteriorly in the sagittal plane and 11.6° laterally in the coronal plane with a length around 30.4 mm. The feasibility of anterior AC screw fixation was 92% (35/38 cases). There is a risk of injury to the vertebral artery and the hypoglossal nerve. Anterior AC transarticular screw fixation is feasible and can be considered as a salvage technique or an alternative for the posterior AC fixation, as well as the supplement to the anterior occipitocervical fixation. 3.

A new method for reducing operation time and radiation exposure in the placement of Jamshidi needles: Technical note

Percutaneous pedicle screws have been used in the treatment of thoracolumbar fractures for decades, and conventional fluoroscopy is commonly used to confirm the positions of the Jamshidi needles during the procedure. In this article, a modified method is reported for the placement of Jamshidi needles. The attending surgeons did not receive any radiation during the procedure and the fluoroscopy time for the patients was little. In our method, all six Jamshidi needles were placed on the pedicles and hammered 2 mm into each entry site. When the verification images were acquired, the medical personnel went behind a lead-lined wall. The positions of the needles were first reviewed and adjusted as needed based on the anterior-posterior (AP) image. Then, the C-arm was rotated and lateral images were obtained to further verify the needle placement. The rest of the screw placement procedure remained the same. The proposed technique was applied in 45 patients with thoracolumbar fractures. It took an average (range) of 5 (4–7) single-shot images to ensure all the needles were positioned at the ideal entry site and 12 (10–17) minutes to complete this step. No neurological symptoms were reported by the patients. Using the proposed technique, the radiation exposure for the surgeons is zero, and the patients are well-protected from excessive radiation exposure. This modified method of embedding all the Jamshidi needles at the entry sites before fluoroscopy is an improved technique compared with the conventional method.

P122. 3D printing technique in the surgery planning of C1-2 dislocation combined with and basilar invagination and occipitalization

BACKGROUND CONTEXT Surgery planning of the C1-2 dislocation with and basilar invagination and occipitalization has changed significantly with the advent of 3D virtual techniques. However, it is still limited by its dependence on computer workstations, its lack of tactile experience and the inability to simulate surgical procedures and interventions. Recently the rapid prototyping or so called 3D printing technology could solve these problems. PURPOSE To introduce the technique of 3D printing model to surgically plan the C1-2 dislocation with and basilar invagination and occipitalization. STUDY DESIGN/SETTING This was a prospective observational study From January 2015 to December 2016. PATIENT SAMPLE A total of 24 cases undertook 3D printing modes at our institution. OUTCOME MEASURES The bone and model measurement of the width of C2 pedicle were compared to assess the anatomical accuracy of the 3D printed models. The neurologic assessment was evaluated by Japanese Orthopedic Association (JOA) score before and after surgery. METHODS The anatomy of the 3D printed model was thoroughly evaluated and the scheme of the operation was designed. The posterior fixation option was chosen according to the anatomical characteristics of C1 lateral mass and the width of C2 pars. The simulation of screw insertion was made to obtain the ideal entry point and screw trajectory. After obtaining the individual data in 3D printing modes, the according surgical operations were performed. RESULTS A total of 24 patients underwent this patient-specific perioperative simulation of procedures and intraoperative orientation guided by 3D printed model between the ages of 15 and 40 years (mean: 25.8 years). There was no intraoperative neurovascular injury in all cases. The operative time ranged from 120 to 220 minutes (mean: 150±18 minutes), and blood loss ranged from 90 to 380 mL (mean: 110±35 mL). Neurological improvement was observed in all 24 patients, with the JOA scores increasing from preoperative 10.1 to postoperative 15.5 (p˂0.01). CONCLUSIONS 3D printing mode could provide thorough information of the bony structure abnormalities and route of vertebral artery. It is helpful for setting operation strategy and designing screw entry point and trajectory and avoiding vertebral artery and spinal cord injury and thus deserves generalization. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Neuropsychiatric phenotypes and a distinct constellation of ASD features in 3q29 deletion syndrome: results from the 3q29 registry

BackgroundThe 1.6 Mb 3q29 deletion is associated with neurodevelopmental and psychiatric phenotypes, including increased risk for autism spectrum disorder (ASD) and a 20 to 40-fold increased risk for schizophrenia. However, the phenotypic spectrum of the deletion, particularly with respect to ASD, remains poorly described.MethodsWe ascertained individuals with 3q29 deletion syndrome (3q29Del, “cases,” n = 93, 58.1% male) and typically developing controls (n = 64, 51.6% male) through the 3q29 registry (https://3q29deletion.patientcrossroads.org). Self-report of neuropsychiatric illness was evaluated for 93 cases. Subsets of participants were evaluated with the Social Responsiveness Scale (SRS, n = 48 cases, 56 controls), Social Communication Questionnaire (n = 33 cases, 46 controls), Autism Spectrum Screening Questionnaire (n = 24 cases, 35 controls), and Achenbach Behavior Checklists (n = 48 cases, 57 controls).Results3q29Del cases report a higher prevalence of autism diagnoses versus the general population (29.0% vs. 1.47%, p < 2.2E− 16). Notably, 3q29 deletion confers a greater influence on risk for ASD in females (OR = 41.8, p = 4.78E− 05) than in males (OR = 24.6, p = 6.06E− 09); this is aligned with the reduced male:female bias from 4:1 in the general population to 2:1 in our study sample. Although 71% of cases do not report a diagnosis of ASD, there is evidence of significant social disability (3q29Del SRS T-score = 71.8, control SRS T-score = 45.9, p = 2.16E− 13). Cases also report increased frequency of generalized anxiety disorder compared to controls (28.0% vs. 6.2%, p = 0.001), which is mirrored by elevated mean scores on the Achenbach diagnostic and statistical manual-oriented sub-scales (p < 0.001). Finally, cases show a distinct constellation of ASD features on the SRS as compared to idiopathic ASD, with substantially elevated Restricted Interests and Repetitive Behaviors, but only mild impairment in Social Motivation.ConclusionsOur sample of 3q29Del is significantly enriched for ASD diagnosis, especially among females, and features of autism may be present even when an ASD diagnosis is not reported. Further, the constellation of ASD features in this population is distinct from idiopathic ASD, with substantially less impaired social motivation. Our study implies that ASD evaluation should be the standard of care for individuals with 3q29Del. From a research perspective, the distinct ASD subtype present in 3q29Del is an ideal entry point for expanding understanding of ASD.

Clival screw and plate fixation by the transoral approach for the craniovertebral junction: a CT-based feasibility study.

A clivus screw and plate was invented and proved to strengthen the stability of the craniovertebral junction (CVJ). However, it is unclear whether the clivus screw and plate could be placed onto the CVJ by transoral approach. Therefore, the present study aims to evaluate the feasibility of clivus screw and plate placement by transoral approach and investigate its relative anatomic parameters. A total of 80 normal adults (40 males/40 females) with an average age of 60.4 ± 11.6years old were enrolled in this study. All parameters were measured in a supposed maximums mouth-opening status on computed tomography images, where the vertex of lower incisor was defined as Point A. The vertical intersection from Point A to extracranial clivus was defined as Point B, and its distance to the bottom of clivus was measured as B length. Point B was considered as ideal screw entry point. All the cases were divided into three types based on the location of Point B: above the top portion (Type 1), between the top and bottom portion (Type 2), and below the bottom portion (Type 3) of extracranial clivus. The B Length was defined as a minus value if the case belonged to Type 3. The anterior skull base angle, the angles between tangent of extracranial clivus and the lines from Point A to different parts of clivus, and distances between Point A and clivus and C1-3 vertebra were also measured. One in eighty cases (1.2%) belonged to Type 1 with a B Length of 32.12mm. Most cases (61.3%) were Type 2 with a B Length of 8.7mm, while Type 3's was - 9.7mm occupying for 37.5%. Significant statistic differences were found in anterior skull base angle between these three types (128.9°, 122.7° and 118.5° for Type 1, 2 and 3, respectively). The distances from Point A to the top and bottom portion of the clivus and the pharyngeal tubercle were 97.5, 96.0 and 96.8mm, respectively. The angles between the tangent of the clivus and the lines from Point A to the above three structures were 75.7°, 92.3° and 84.0°, respectively. The distances from Point A to the middle point of anterior margin of C1 anterior tubercle, C2 vertebra and C3 vertebra were 79.1, 73.4 and 61.5mm, respectively. The clivus screw and plate placement could be accomplished with optimal screw angle by transoral approach in most of patients. Mandibular splitting would be needed in patients with greater anterior skull angle. These slides can be retrieved under Electronic Supplementary Material.

The Paradox of Positionality: Avoiding, Embracing, or Resisting Feminist Accountability

ABSTRACTWrestling with the desirability and possibility of research objectivity, scholars across disciplines debate the claim that there can ever be value-free research. While many sociocultural scholars defend and strive for research objectivity, feminists tend to reject such approaches and instead continue to call on scholars to position themselves in their research presentations and publications in relation to the topic being studied, and in the case of empirical work, their participants. We might think of this call as a feminist accountability, which we suggest most scholars avoid, some embrace, and others resist. One can avoid positioning themselves in their research, but we contend in doing so they potentially stabilize dangerous claims that surround the desirability and possibility of research objectivity. Those who embrace accountability by positioning themselves in their analyses are not without their own risks. They often have to vulnerably share intimate details about themselves or their loved ones. For those who embrace accountability and are members of a marginalized community they are studying, they are also likely to experience heightened accusations that their research is biased and/or a self-discovery project derogatorily referred to as “mesearch.” Others who resist feminist accountability might do so for good reason especially for scholars studying very stigmatized phenomena, but it is likely folks who engage their work will still make problematic assumptions about their bodies, identities, and experiences. It is through the various ways of navigating this feminist accountability that we offer the paradox of positionality and contend that fat studies scholarship is an ideal entry point into its theorization.

Anterior Atlanto-Occipital Transarticular Screw Fixation: A Radiological Evaluation

In situations in which posterior atlanto-occipital fixation might not be possible or might require supplemental fixation, anterior fixation might add stability in obtaining arthrodesis. The present study aimed to provide a radiographic evaluation of the safety and feasibility in the anterior approach. The bilateral craniocervical computed tomography slices of 60 patients were examined. The anterior screw entry point was the lowest point at the middle anterior aspect of C1 (atlas) lateral mass. To avoid hypoglossal canal and craniocerebral injury, the height of the hypoglossal canal and occipital condyle and occipital condyle width were obtained. The mandible occlusion angle (MOA), anterior screw trajectory above, under, and distal to the hypoglossal canal (AHA, UHA, and DHA) relative to the tangent line of C1 front border were measured, together with the maximum screw length under each angle (AHL, UHL and DHL). An independent samples ttest was used for statistical analysis. The height of the hypoglossal canal and occipital condyle and occipital condyle width were all larger in the men than in the women. The MOA, AHA, UHA, and DHA were 55.0°, 18.7°, 41.0°, and 55.0°, respectively, and were similar between genders. The AHL, UHL, and DHL were 34.5, 30.9, and 31.3 mm, with the measurements for the men generally longer than those for the women by 3-4 mm. A total of 10 of 120 bilateral measurements showed the possibility of mandible occlusion, and the potential success rate of the anterior approach could reach 91.7%. The ideal entry angle for anterior atlanto-occipital fixation ranges from 41.0° to 55.0°, with a safe screw length from 30.9 to 31.3 mm. The potential success rate could reach >90%.

Computational simulation of sacral-alar-iliac (S2AI) screw fixation of pelvis and implications for fluoroscopic procedure: A cadaver study.

To determine an easy and convenient method of sacral-alar-iliac (S2AI) screw fixation and introduce the surgical landmarks for fluoroscopic procedure by analyzing 3-D models of pelvis and virtual implantation in a 3-D model. Eighty-two cadavers underwent computed tomography scans and the images imported into Mimics® software to make the 3-D pelvis model. The pedicle screw (Ø 8.5 mm/length 115 mm) was processed into a 3-D model using a 3-D-sensor (Comet5®) at the actual size and virtually placed as the S2AI screw. The ideal screw position was defined as the maximal intraosseous length without cortical perforation along the entire path. The ideal entry point and screw trajectory were verified and assessed to introduce the surgical landmark for fluoroscopic procedure. There was no cortical violation around nerve root canal and greater sciatic notch through the entry point between first and second dorsal sacral foramen. There was no impossible model of S2AI screws. The average screw length was 99.8 mm (range, 59.8-115 mm; standard deviation, 16.1) and just one model had shorter than 65 mm S2AI screw. The factors limiting the intra-iliac screw length were sex ( p = 0.000) and the iliac groove around the sacroiliac joint ( p = 0.000). A free 360° rotation with magnification revealed that the screw trajectory was consistently directed toward the anteroinferior iliac spine (AIIS) in any plane. The ideal entry point of S2AI screw showed a wide range of tolerance between the first and second dorsal sacral foramen; and thus, there was no need for deep dissection to identify the first dorsal sacral foramen. Considering the tendency to shift the pilot hole laterally and the ideal screw trajectory was consistently directed toward AIIS, the entry point is better to be located with a medial shift.

Clinical Application and Efficacy Analysis of 3D Navigation Module in the Treatment of Atlantoaxial Instability

Background: Posterior cervical atlantoaxial pedicle screw fixation is a very effective treatment for atlantoaxial instability (AAI). However, due to the complex anatomy of the cranial-cervical junction, the accuracy and safety of posterior atlantoaxial pedicle screw placement remains extremely challenging. Objective: To quantitatively evaluate the safety and accuracy of the 3D navigation module to assist the posterior atlantoaxial fixation. Methods: A total of 20 AAI patients were selected between June 2014 and September 2015. The Mimics v10.1 and 3-matic software were used. The 3D navigation module was designed as a double-sided positioning hole guide with a guide rod. All patients underwent posterior atlantoaxial posterior pedicle screw fixation with 3D navigation module. The actual entry point and screw trajectory were measured after operation, which were compared with the ideal entry point and screw trajectory. The Japanese Orthopaedic Association (JOA) score was measured before and after surgery to evaluate the neurological function improvement. The average operation time, blood loss, and frequency of intraoperative fluoroscopy were counted. Results: The posterior atlantoaxial pedicle screw fixation with a 3D navigation module was successfully performed in all patients. A total of 80 atlantoaxial pedicle screws were implanted in the 20 patients. Postoperative CT scan showed that two pedicle screws deviated from the medial aspect of the atlas pedicle cortex and entered the spinal canal approximately 1 mm, without causing neurological complications. There was no significant difference between the ideal and actual entry points or ideal and actual screw trajectories of the atlas and axis (P &gt; 0.05). The preoperative JOA score was 12.45 ± 1.15 and postoperative JOA score was 15.5 ± 0.89, with statistically significant difference (P &lt; 0.05). Conclusion: It was safe and effective to use the 3D navigation module to assist the posterior atlantoaxial pedicle insertion, with a high accuracy of pedicle screw placement. Keywords: atlantoaxial instability, pedicle screw, 3D navigation module, rapid prototyping

Intra-medullary nail insertion accuracy: A comparison of the infra-patellar and supra-patellar approach

AimsThe anatomical safe zone for intra-medullary nail insertion through the tibial plateau is small, insertion outside of this area risks damage to intra-articular structures and poor fracture reduction. The purpose of this retrospective study was to determine if the new supra-patella (SP) approach confers improved nail insertion accuracy, when compared with the standard infra-patella (IP) technique. Patients and MethodsTwo hundred cases were included in the study (SP 95, IP 105). Insertion accuracy was assessed on AP and lateral radiographic imaging, and measured as the distances between the central axis of the proximal nail and the ideal entry point. ResultsThe median distance from the ideal entry point was 4.4 mm (SP) and 5.1 mm (IP) (p = 0.046) in the coronal plane, and 4.0 mm (SP) and 3.7 mm (IP) (p = 0.527) in the sagittal plane. A narrower range in measurements was observed in the SP technique in both sagittal and coronal planes, 17.8 mm vs 28.6 mm, and 19.7 mm vs 30.3 mm respectively. ConclusionWe found that the SP technique achieved significantly improved nail insertion accuracy in the coronal plane. Insertion accuracy was equivocal between the two techniques in the sagittal plane. A narrower range in entry points was observed in the SP cohort in both planes suggesting improved control in nail insertion using this technique.

Evaluation of Some Traits in Local Iranian Quince (Cydonia Oblonga Miller) Genotypes

ABSTRACTQuince (Cydonia oblonga Miller.) belongs to the Rosaceae family and is generally used for fresh consumption and processed items. In this research, fruit characteristics of eight quince genotypes from Iran were investigated via genotype by trait interactions (GTI) biplot. Results indicated that the first two principal components analysis (PC1 and PC2) were used to create a two-dimensional GTI biplot that accounted percentages of 31% and 22%, respectively, of sums of squares of the GTI. The vertex genotypes in polygon were Svs1, Esf, Nb1, Kud2 and Et1; and Svs1 was the winning genotype for pectin, fruit length, phosphorus percent and fruit hardness while Esf was the best genotype for iron percent, fruit diameter, fruit weight and end hold. There were positive correlation among pectin, fruit length, fruit hardness and phosphorus percent as well as among zinc percent, branch length, fruit apparent specific weight, calcium percent and potassium percent. Genotype Svs1 was more desirable followed by genotypes Nb4, Esf and Et1 based on ideal entry biplot and pectin and fruit length were the best traits according to ideal tester biplot. The best genotype for obtaining of high fruit weight was Esf following to Nb4, Svs1 and Nb1 and ranking traits based on fruit weight showed that fruit diameter is more important followed by end hold and iron percent. This study showed that there was relatively high level of variation in quince genotypes grown and morphological traits used in this research indicating that they can be used for characterization and diversity analysis of quince. We concluded from this study that it is imperative for breeders to pay more attention to improve quince morphological traits coordinated to fruit yield performance.

An Innovative Three-Dimensional Method for Identifying a Proper Femoral Intramedullary Entry Point in Total Knee Arthroplasty

Background:Identification of the proper femoral intramedullary (IM) access point is an important determinant of final implant position in IM-guided total knee arthroplasty (TKA). The aim of this study was to identify the optimal entry point in Chinese participants using a new three-dimensional method.Methods:A series of computed tomography scans of 44 femurs in Chinese participants from October 2014 to October 2015 were imported into Mimics 17.0 software to identify the optimal entry point. The apex of the intercondylar notch (AIN) was used as the reference bony anatomical landmark to identify the proper entry point to insert the IM rod. The statistical significance was calculated on the basis of a 5% level (P < 0.05) using the Student's t-test.Results:For the males, the average ideal entry point was 1.49 mm medial and 13.39 mm anterior to the AIN. The values were 1.77 mm medial and 15.29 mm anterior to the AIN in females. A significant difference was present between males and females (13.39 ± 2.46 mm vs. 15.29 ± 3.44 mm, t = 2.124, P = 0.040). When using the recommended location as the entry point for the IM rod, the mean potential error differed significantly from the femoral trochlear groove (the potential error of IM in males in coronal plane: 0.93° ± 0.24° vs. 1.27° ± 0.32°, t = −4.166, P < 0.001; the potential error of IM in males in sagittal plane: 1.40° ± 0.42° vs. 2.79° ± 0.70°, t = −7.155, P < 0.001; the potential error of IM in females in coronal plane: 0.73° ± 0.28° vs. 1.15° ± 0.35°, t = −3.940, P < 0.001; and the potential error of IM in females in sagittal plane: 1.48° ± 0.47° vs. 2.76° ± 0.83°, t = −5.574, P < 0.001). A significant difference was present between the recommended point and the point 10 mm anterior to the origin of the posterior cruciate ligament (the potential error of IM in males in coronal plane: 0.93° ± 0.24° vs. 1.53° ± 0.43°, t = −5.948, P < 0.001; the potential error of IM in males in sagittal plane: 1.40° ± 0.42° vs. 2.15° ± 0.75°, t = −3.152, P = 0.003; the potential error of IM in females in coronal plane: 0.73° ± 0.28° vs. 1.28° ± 0.42°, t = −4.632, P < 0.001; and the potential error of IM in females in sagittal plane: 1.48° ± 0.47° vs. 2.40° ± 0.93°, t = −3.763, P = 0.001).Conclusions:The technique described here is an innovative method for swift, easy, and accurate access to the medullary canal during TKA, and it can optimize the position and orientation of the prosthetic components in knee arthroplasty.

Just Transitions in a Public School Food System: The Case of Buffalo, New York

This article examines the public school food system in Buffalo, New York, for a just transition (Movement Generation, n. d.). School food programs built on just transition characteristics democratize engagement, decentralize decision-making, diversify the economy, decrease consump­tion, and redistribute resources and power. The Buffalo public school district’s food system is an important subsection of the city’s food system that reaches the most vulnerable populations. School food systems contain teachable spaces within schools to introduce students to healthy eating, fresh food, and the (in)equitable economies of the larger community food system. We argue that school food is an ideal entry point for introducing a just transition to the local food system, enhancing food equity built from healthier social, economic, ecological, and political systems. Related to this JAFSCD issue’s call on Local Government in Food Systems Work, we aim to bring attention to the role and responsibility of public education systems in managing and enhancing community food systems through public policy. This qualitative case study examines five public school food programs in Buffalo, New York, for characteristics of a just transition using content analysis of policy and program documents. How does one public school food system engage in and build toward a just transition? Key findings include that all five pro­grams analyzed reflected at least one characteristic of a just transition; programs lacked an emphasis on ecological justice; and younger generations must be included in the just transition implementation process. Ultimately, we argue that the school food system is ideally poised to initiate the implementa­tion of a just transition.

The Mediating Role of TMT Attention in Foreign Entry Mode Selections

According to the attention-based view (ABV) of the firm (Ocasio, 1997) and the upper-echelon theory (Hambrick et al., 1984), TMT (top management team) attention plays an important role in strategic decision making, especially in the more complicated international context (Aharoni et al., 2011). By combining the attention-based view and upper-echelon theory, we built and tested an attention-based, decision-making model to open up the “black box” of the TMT decision-making process to examine how a TMT identifies the ideal entry mode to invest in a foreign market. By analyzing data from 116 manufacturing firms listed on the Chinese Stock Exchanges, we found that TMT’s attention to the opportunities in the foreign market mediates the relationship between TMT characteristics and their choice of foreign entry mode. Specifically, a TMT having members with more international experience or higher levels of education tends to pay more attention to the opportunities in the external environment; thus selecting a full-control entry mode. Whereas a TMT comprised of aged members tends to pay less attention to the external opportunities in the foreign market and selects a shared-control mode.