scholarly journals Use of computed tomography to define a sacral safe corridor for placement of 2.7 mm cortical screws in feline sacroiliac luxation

2017 ◽  
Vol 20 (6) ◽  
pp. 487-493
Author(s):  
Helen Philp ◽  
Alexane Durand ◽  
Felipe De Vicente
Keyword(s):  
Ct Scan ◽  
Safety Margin ◽  
Transverse Plane ◽  
Screw Placement ◽  
Radiographic Measurement ◽  
Screw Insertion ◽  
Cortical Screw ◽  
Maximum Angle ◽  
Minimum Angle ◽  
The Mean

Objectives This study aimed to define a safe corridor for 2.7 mm cortical sacroiliac screw insertion in the dorsal plane (craniocaudal direction) using radiography and CT, and in the transverse plane (dorsoventral direction) using CT in feline cadavers. A further aim was to compare the values obtained by CT with those previously reported by radiography in the transverse plane. Methods Thirteen pelvises were retrieved from feline cadavers and dissected to expose one of the articular surfaces of the sacrum. A 2.7 mm screw was placed in the sacrum to a depth of approximately 1 cm in each exposed articular surface. Dorsoventral radiography and CT scanning of each specimen were performed. Multiplanar reconstructions were performed to allow CT evaluation in both the dorsal and transverse planes. Calculations were made to find the maximum, minimum and optimum angles for screw placement in craniocaudal (radiography and CT) and dorsoventral (CT) directions when using a 2.7 mm cortical screw. Results Radiographic measurement showed a mean optimum craniocaudal angle of 106° (range 97–112°). The mean minimum angle was 95° (range 87–107°), whereas the mean maximum angle was 117° (108–124°). Measurement of the dorsal CT scan images showed a mean optimum craniocaudal angle of 101° (range 94–110°). The mean minimum angle was 90° (range 83–99°), whereas the mean maximum angle was 113° (104–125°). The transverse CT scan images showed a mean dorsoventral minimum angle of 103° (range 95–113°), mean maximum angle of 115° (104–125°) and mean optimum dorsoventral angle of 111° (102–119°). Conclusions and relevance An optimum craniocaudal angle of 101° is recommended for 2.7 mm cortical screw placement in the feline sacral body, with a safety margin between 99° and 104°. No single angle can be recommended in the dorsoventral direction and therefore preoperative measuring on individual cats using CT images is recommended to establish the ideal individual angle in the transverse plane.

scholarly journals Radiographic parameters and a novel fluoroscopic control view for posterior screw fixation of coracoid base fractures

SICOT-J ◽  
2020 ◽  
Vol 6 ◽  
pp. 9
Author(s):  
Hatem Galal Said ◽  
Tarek Nabil Fetih ◽  
Hosam Elsayed Abd-Elzaher ◽  
Simon Martin Lambert
Keyword(s):  
Sagittal Plane ◽  
Coracoid Process ◽  
Entry Point ◽  
Coronal Plane ◽  
Screw Placement ◽  
Posterior Fixation ◽  
Screw Insertion ◽  
Screw Length ◽  
Scapular Spine ◽  
The Mean

Introduction: Coracoid fractures have the potential to lead to inadequate shoulder function. Most coracoid base fractures occur with scapular fractures and the posterior approaches would be utilized for surgical treatment. We investigated the possibility of fixing the coracoid through the same approach without an additional anterior approach. Materials and methods: Multi-slice CT scans of 30 shoulders were examined and the following measurements were performed by an independent specialized radiologist: posterior coracoid screw entry point measured form infraglenoid tubercle, screw trajectory in coronal plane in relation to scapular spine and lateral scapular border, screw trajectory in sagittal plane in relation to glenoid face bisector line and screw length. We used the results from the CT study to guide postero-anterior coracoid screw insertion under fluoroscopic guidance on two fresh frozen cadaveric specimens to assess the reproducibility of accurate screw placement based on these parameters. We also developed a novel fluoroscopic projection, the anteroposterior (AP) coracoid view, to guide screw placement in the para-coronal plane. Results: The mean distance between entry point and the infraglenoid tubercle was 10.8 mm (range: 9.2–13.9, SD 1.36). The mean screw length was 52 mm (range: 46.7–58.5, SD 3.3). The mean sagittal inclination angle between was 44.7 degrees (range: 25–59, SD 5.8). The mean angle between screw line and lateral scapular border was 47.9 degrees (range: 34–58, SD 4.3). The mean angle between screw line and scapular spine was 86.2 degrees (range: 75–95, SD 4.9). It was easy to reproduce the screw trajectory in the para-coronal plane; however, multiple attempts were needed to reach the correct angle in the parasagittal plane, requiring several C-arm corrections. Conclusion: This study facilitates posterior fixation of coracoid process fractures and will inform the “virtual visualization” of coracoid process orientation.

THE PATH OF SCREW INSERTION FOR STABILIZATION OF THE SCAPHOLUNATE JOINT: A CADAVERIC STUDY

Hand Surgery ◽  
2014 ◽  
Vol 19 (01) ◽  
pp. 145-149
Author(s):  
O. M. Flannery ◽  
L. C. Murphy ◽  
P. Dockery ◽  
M. E. O'Sullivan
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
Articular Surface ◽  
Cadaveric Study ◽  
Screw Placement ◽  
Ulnar Styloid ◽  
Screw Insertion ◽  
Articular Surfaces ◽  
Radial Styloid ◽  
The Right

The aim of this study was to determine the path of screw placement to avoid breaching the articular surface of both lunate and scaphoid bones at the radiocarpal and midcarpal joints. An Acutrak screw was inserted into the right scapholunate joint of ten cadavers starting immediately distal to the tip of the radial styloid and aiming for the tip of the ulnar styloid. The articular surfaces of the scaphoid and lunate bones in all ten cadavers were exposed and examined. A computed tomography (CT) scan of four wrists was performed. Eight of the ten cadavers had no perforation or destruction of the articular surfaces. Screw stabilization of the scapholunate joint can be performed without perforation or destruction of the lunate or scaphoid surfaces. We recommend that if this form of fixation is being used then the screw should be inserted commencing at the radial styloid tip and aiming for ulnar styloid tip, under radiological guidance.

scholarly journals Comparative Study of Y-Split Recession versus Faden Technique for Management of Infantile Esotropia in Egyptians

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Nermeen Badawi ◽  
Ahmed Taha Ismail
Keyword(s):  
Age Distribution ◽  
Angle Measurement ◽  
Infantile Esotropia ◽  
Maximum Angle ◽  
Minimum Angle ◽  
Group A ◽  
Angle Of Deviation ◽  
The Mean ◽  
Group B

Purpose. This study compares the results of Y-split recession versus de Decker’s (modified Cüppers) Faden techniques of medial rectus (MR) muscles for the management of essential infantile esotropia (IET). Patients and Methods. Fifty patients had IET divided into Group A who underwent Y-split recession of MR muscles and Group B who underwent de Decker’s Faden technique of MR muscles. All patients had complete ophthalmic examination done including deviation angle measurement and met the inclusion criteria of the study. Operations were performed using general anesthesia. Patients were followed up at day 1, week 1, and months 1, 3, and 6 after operation. Results. The mean age distribution for group A was 21.56 months (SD 12.55) and for group B was 21.4 months (SD 12.35), and the mean postoperative follow-up interval was 6 months for both groups. The preoperative maximum angle of deviation in both groups ranged from 15 to 40 degrees, while the minimum angle of deviation ranged from 10 to 20 degrees. Immediately postoperatively both groups showed 88% of patients with satisfactory results (within 10 degrees of orthotropia). Group A showed two patients (8%) with ET and one patient (4%) with exotropia (XT). For group B, it showed one patient (4%) with ET and two patients (8%) with XT. Three patients in each group underwent a second intervention. All patients remained within the satisfactory range. Conclusion. The results of this study suggest that both techniques show comparable results for the correction of IET.

scholarly journals Tomographic Evaluation of Mandibular Thickness on Premolar and Molar Regions Related to Monocortical Screws

2016 ◽  
Vol 9 (2) ◽  
pp. 105-108
Author(s):  
Jonathan Ribeiro ◽  
Charles Marin ◽  
Nicolas Homsi ◽  
Hernando Rocha Junior ◽  
Luiz Magacho ◽  
...  
Keyword(s):  
Ct Scan ◽  
Safety Margin ◽  
Anatomical Variations ◽  
Cortical Plate ◽  
Rigid Fixation ◽  
The Mean ◽  
Post Hoc ◽  
One Way Anova ◽  
Molar Region ◽  
Monocortical Screws

The aim of this study was to measure the thickness of the mandible from the external cortical plate to the teeth roots on premolar and molar regions using CT scan to determine the safety margin for the application of monocortical screws for internal rigid fixation. Thirty-one patients underwent CT-scan imaging for surgical planning. The images were used to measure bilaterally the distance from the external cortex of the mandible to the roots of teeth on premolar and molar region by means of Dental Slice software (Bioparts Prototipagem Biomedica, Brasília, DF, Brazil). Mean, median, standard deviation, one-way ANOVA and post hoc Tukey's test were used for statistical analysis. No statistical differences for thickness were found between right and left side ( p = 0.1652). The mean thickness for the left side was 4.17 ± 1.68 mm and for right side 3.93 ± 1.49 mm. Increase in mandibular thickness from anterior to posterior regions in both sides was observed and statistical difference was found among the different groups according to the measured region ( p < 0.05). The present results can predict the safety zone for the use of monocortical screws in the mandible, but the use of CT scan is imperative and individual analysis is desired owing to anatomical variations. Further studies with larger samples are necessary to confirm these data and should include other anatomic structures, different regions of mandible/maxilla, as well as other ethnic groups.

Working area, safety zones, and angles of approach for posterior C-1 lateral mass screw placement: a quantitative anatomical and morphometric evaluation

2007 ◽  
Vol 6 (3) ◽  
pp. 247-254 ◽  
Author(s):  
Rogerio Rocha ◽  
Sam Safavi-Abbasi ◽  
Cassius Reis ◽  
Nicholas Theodore ◽  
Nicholas Bambakidis ◽  
...  
Keyword(s):  
Screw Placement ◽  
Posterior Arch ◽  
Depth Range ◽  
Entry Site ◽  
Transverse Foramen ◽  
Digital Radiographs ◽  
Maximum Angle ◽  
The Mean ◽  
Risk Of Hemorrhage ◽  
Neurovascular Anatomy

Object The authors measured relevant quantitative anatomical parameters to define safety zones for the placement of C-1 posterior screws. Methods Nineteen linear, two angular, and four surface parameters of 20 dried atlantal specimens were evaluated. The Optotrak 3020 system was used to define the working area. Ideal angles for screw positioning were measured using digital radiographs and a free image-processing program. Six silicone-injected cadaveric heads were dissected bilaterally to study related neurovascular anatomy. The depth (range 5.2–9.4 mm, mean 7.2 ± 1.1 mm) and width (range 5.2–8.1 mm, mean 6.5 ± 0.9 mm) of the transverse foramen varied considerably among specimens. The mean posterior working area was 43.3 mm2. All specimens accommodated 3.5-mm-diameter screws, and 93% accepted 4-mm-diameter screws. In 10 specimens (50%), partial removal of the posterior arch was necessary to accommodate a 4-mm screw. The mean maximum angle of medialization was 16.7 ± 1.3°; the mean maximum superior angulation was 21.7 ± 4.7°. Conclusions The anatomical configuration of the atlas and vertebral artery (VA) varied considerably among the cadaveric specimens. The heights of the C-1 pedicle, posterior arch, and posterior lamina determine the posterior working area available for screw placement. The inferior insertion of the posterior arch may have to be drilled to increase this working area, but doing so risks injury to the VA. A dense venous plexus with multiple anastomoses may cover the screw entry site, potentially obscuring the operative view and increasing the risk of hemorrhage.

scholarly journals Transfixing Screw Placement for Syndesmotic Injury

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0031
Author(s):  
Si Wook Lee
Keyword(s):  
Ct Scan ◽  
Screw Fixation ◽  
Screw Placement ◽  
Neutral Position ◽  
Syndesmotic Injury ◽  
Interosseous Ligament ◽  
Screw Insertion ◽  
Insertion Angle ◽  
Significant Difference ◽  
Fresh Frozen

Category: Trauma Introduction/Purpose: The strategy of transfixing screw fixation including screw number, size, material, the number of cortex involved, and penetrating angle is controversial. The purpose of this fresh frozen cadaveric study is to demonstrate the optimal degree of transfixing screw insertion after syndesmotic reduction in the Pronation External Rotation (PER) type ankle fractures, and to study reliable parameters to evaluate the syndesmotic reduction. Methods: Twenty paired fresh frozen anatomic specimens of the ankles were obtained. Before dissection, CT scans were taken preoperatively. Then, preparation was performed by cutting and dissection of anterior interior tibiofibular ligament (AITFL), interosseous ligament and membrane. Two types of screw placement were set. Ten screws were inserted into right ankle at an angle of 25 to 30 degrees from neutral position. The other 10 screws were inserted into the left ankle at a 0 degree angle from neutral position. Postoperative CT scan was performed after screw insertion. Anterior fibular distance(AFD), posterior fibular distance(PFD), anterior translation distance(AT), diastasis, anterior-posterior translation(APT) were measured in 2D axial section and volume of the syndesmotic space were measured in 3D reconstruction data of preoperative and postoperative CT scan. Results: The transfixing screw fixation induce the significant difference in syndesmotic space regardless of insertion angle. There was significant difference only in fibular diastasis between both ankle model. There was no statistically significant difference in AFD, PFD, AT, APT and 3D reconstructed volume according to transfixing screw insertion angle when each measured value was compared through left and right ratio and absolute volume value. Conclusion: In ankle syndesmotic injury, transfixing screw insertion should be considered for the ankle stability. But, regardless of the insertion angle, transfixing screw insertion would have a significant therapeutic effect on ankle syndesmotic injury. Fibular diastasis would be the reliable parameters to evaluate syndesmotic reduction.

Pullout Strength of Screws in Foal Third Metacarpal Bone after Overdrilling a 4.5 mm Hole

1998 ◽  
Vol 11 (04) ◽  
pp. 200-204 ◽  
Author(s):  
K. Kelly ◽  
G. S. Martin ◽  
D. J. Burba ◽  
S. A. Sedrish ◽  
R. M. Moore
Keyword(s):  
Cortical Bone ◽  
Metacarpal Bone ◽  
Pullout Strength ◽  
Cancellous Screw ◽  
Bone Screw ◽  
Screw Insertion ◽  
Holding Power ◽  
Cortical Screw ◽  
Metaphyseal Bone

SummaryThe purpose of the study was to determine and to compare the in vitro pullout strength of 5.5 mm cortical versus 6.5 mm cancellous bone screws inserted in the diaphysis and metaphysis of foal third metacarpal (MCIII) bones in threaded 4.5 mm cortical bone screw insertion holes that were then overdrilled with a 4.5 mm drill bit. This information is relevant to the selection of a replacement screw if a 4.5 mm cortical screw is stripped during orthopaedic surgery. In vitro pullout tests were performed in two independent cadaver studies, each consisting of 12 foal MCIII bones. Two 4.5 mm cortical screws were placed either in the mid-diaphysis (study 1) or distal metaphysis (study 2) of MCIII bones. The holes were then overdrilled with a 4.5 mm bit and had either a 5.5 mm cortical or a 6.5 mm cancellous screw inserted; screw pullout tests were performed at a rate of 0.04 mm/s until screw or bone failure occurred.The bone failed in all of the tests in the diaphyseal and metaphyseal bone. The holding power for 6.5 mm cancellous screws was significantly (p <0.05) greater than for 5.5 mm cortical screws in both the diaphysis and metaphysis. There was not any difference in the holding power of screws in either the diaphysis or the metaphysis between proximal and distal screw holes.If a 4.5 mm cortical bone screw strips in MCIII diaphyseal or metaphyseal bone of foals, a 6.5 mm cancellous screw would provide greater holding power than a 5.5 mm cortical screw.In order to provide information regarding selection of a replacement screw if a 4.5 mm cortical screw is stripped, the in vitro pullout strength was determined for 5.5 mm cortical and 6.5 mm cancellous screws inserted in third metacarpal diaphyseal and metaphyseal bone of foals in which threaded 4.5 mm cortical bone screw insertion holes had been overdrilled with a 4.5 mm bit. The holding power of the 6.5 mm cancellous screw was significantly greater than the 5.5 mm cortical screw in both the diaphysis and metaphysis of foal third metacarpal bone. Thus, it appears that if a 4.5 mm cortical screw is stripped during orthopaedic surgery in foals, a 6.5 mm cancellous screw would provide superior holding power.

The Y-shaped trabecular bone structure in the odontoid process of the axis: a CT scan study in 54 healthy subjects and biomechanical considerations

2019 ◽  
Vol 30 (5) ◽  
pp. 585-592 ◽  
Author(s):  
Nicola Montemurro ◽  
Paolo Perrini ◽  
Vittoriano Mangini ◽  
Massimo Galli ◽  
Andrea Papini
Keyword(s):  
Ct Scan ◽  
Healthy Subjects ◽  
Bone Structure ◽  
Cone Beam Ct ◽  
Odontoid Process ◽  
Trabecular Structure ◽  
Anatomical Entity ◽  
Significant Difference ◽  
Axial Ct ◽  
The Mean

OBJECTIVEOdontoid process fractures are very common in both young and geriatric patients. The axial trabecular architecture of the dens appears to be crucial for physiological and biomechanical function of the C1–2 joint. The aim of this study is to demonstrate the presence of a Y-shaped trabecular structure of the dens on axial CT and to describe its anatomical and biomechanical implications.METHODSFifty-four C2 odontoid processes in healthy subjects were prospectively examined for the presence of a Y-shaped trabecular structure at the odontocentral synchondrosis level with a dental cone beam CT scan. Length, width, and axial area of the odontoid process were measured in all subjects. In addition, measurements of the one-third right anterior area of the Y-shaped structure were taken.RESULTSThe Y-shaped trabecular structure was found in 79.6% of cases. Length and width of the odontoid process were 13.5 ± 0.6 mm and 11.2 ± 0.9 mm, respectively. The mean area of the odontoid process at the odontocentral synchondrosis was 93.5 ± 4.3 mm2, whereas the mean one-third right anterior area of the odontoid process at the same level was 29.3 ± 2.5 mm2. The mean area of the odontoid process and its length and width were similar in men and women (p > 0.05). No significant difference was found in the mean area of the odontoid process in people older than 65 years (94 ± 4.2 mm2) compared to people younger than 65 years (93.3 ± 4.4 mm2; p > 0.05).CONCLUSIONSThe authors identified a new anatomical entity, named the Y-shaped trabecular structure of the odontoid process, on axial CT scans. This structure appears to be the result of bone transformation induced by the elevated dynamic loading at the C1–2 level. The presence of the Y-shaped structure provides new insights into biomechanical responses of C2 under physiological loading and traumatic conditions.

scholarly journals A useful intraoperative technique for transiliac-transsacral screws: a point-to-point coaxial guide apparatus

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ze-hang Zheng ◽  
Fei Xu ◽  
Zheng-qiang Luo ◽  
Ye Ren ◽  
Tao Fu ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Pelvic Fracture ◽  
Operative Time ◽  
Screw Placement ◽  
Screw Insertion ◽  
Average Operative Time ◽  
Free Hand Technique ◽  
Point To Point ◽  
Postoperative Fracture

Abstract Background The transiliac-transsacral screw placement is a clinical challenge for surgeons. This study explored a point-to-point coaxial guide apparatus assisting the transiliac-transsacral screw insertion and aimed to investigate the feasibility and accuracy of the guide apparatus in the treatment of posterior ring unstable pelvic fracture compared with a free-hand technique. Methods A retrospective study was performed to evaluate patients treated with transiliac-transsacral screws assisted by the point-to-point coaxial guide apparatus or free-hand technique. The intraoperative data of operative time and radiation exposure times were recorded. Postoperative radiographs and CT scans were performed to scrutinize the accuracy of screws position. The quality of the postoperative fracture reduction was assessed according to Matta radiology criteria. The pelvic function was assessed according to the Majeed scoring criteria at 6 months postoperatively. Results From July 2017 to December 2019, a total of 38 patients were included in this study, 20 from the point-to-point guide apparatus group and 18 from the free-hand group. There were no significant differences between the two groups in gender, age, injury causes, pelvic fracture type, screws level, and follow-up time (P > 0.05). The average operative time of the guide apparatus group for each screw was significantly less than that in the free-hand group (25.8 ± 4.7 min vs 40.5 ± 5.1, P < 0.001). The radiation exposure times were significantly lower in the guide apparatus group than that in the free-hand group (24.4 ± 6.0 vs 51.6 ± 8.4, P < 0.001). The intraosseous and juxtacortical rate of screw placement (100%) higher than in the free-hand group (94.4%). Conclusion The point-to-point coaxial guide apparatus is feasible for assisting the transiliac-transsacral screw in the treatment of posterior unstable pelvic fractures. It has the advantages of simple operation, reasonable design and no need for expensive equipment, and provides an additional surgical strategy for the insertion of the transiliac-transsacral screw.

scholarly journals Management of Vertical Sternal Fracture Nonunion in Elite-Level Athletes

2021 ◽  
Vol 9 (6) ◽  
pp. 232596712110108
Author(s):  
Andrea Bardos ◽  
Sanjeeve Sabhrawal ◽  
Graham Tytherleigh-Strong
Keyword(s):  
Ct Scan ◽  
Constant Score ◽  
Case Series ◽  
Sternal Fracture ◽  
Elite Level ◽  
The Mean ◽  
Mean Time ◽  
Time From Injury ◽  
Sternal Fractures

Background: Sternal fractures are rare, and they can be treated nonoperatively. Vertical sternal fractures have rarely been reported. Purpose: To describe the management and surgical treatment of a series of elite-level athletes who presented with symptomatic nonunions of a vertical sternal fracture. Study Design: Case series; Level of evidence, 4. Methods: Patients with an established symptomatic nonunion of a vertical sternal fracture, as diagnosed by computed tomography (CT) or magnetic resonance imaging (MRI), underwent open reduction and internal fixation using autologous bone graft and cannulated lag screws. The patients were assessed preoperatively and at the final follow-up using the Rockwood sternoclavicular joint (SCJ) score; Constant score; and shortened version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores. Bony union was confirmed on postoperative CT scan. Results: Five patients (4 men and 1 woman) were included; all were national- or international-level athletes (rugby, judo, show-jumping, and MotoGP). The mean age at surgery was 23.4 years (range, 19-27 years), the mean time from injury to referral was 13.6 months (range, 10-17 months), and the mean time from injury to surgery was 15.8 months (range, 11-20 months). The mean follow-up was 99.4 months (range, 25-168 months). There was a significant improvement after surgery in the mean Rockwood SCJ score (from 12.6 to 14.8 [ P < .05]), Constant score (from 84 to 96.4 [ P < .05]; 80% met the minimal clinically important difference [MCID] of 10.4 points), and QuickDASH (from 6.8 to 0.98 [ P < .05]; 0% met the MCID of 15.9 points). Four of the patients were able to return to sport at their preinjury level, and 1 patient retired for nonmedical reasons. All of the fractures had united on the postoperative CT scan. There were no postoperative complications. Conclusion: Vertical fractures of the sternum are very rare and tend to behave clinically like an avulsion fracture injury to the capsuloligamentous structure of the inferior SCJ. The requirement of advanced imaging to diagnose this injury means that the actual incidence and natural history are not known. For high-demand athletes, early identification, surgical reduction, and fixation are likely to achieve the best outcome.

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