scholarly journals 3D Mapping of Intra-articular Calcaneal Fractures

2021 ◽  
Author(s):  
Guang Shi ◽  
Hongrui Zhan ◽  
Wei Liu ◽  
Tao Zhang ◽  
Zhao Lin ◽  
...  
Keyword(s):  
Internal Structure ◽  
Three Dimensional ◽  
Lateral Wall ◽  
Fracture Morphology ◽  
Medial Wall ◽  
3D Mapping ◽  
Calcaneal Fractures ◽  
Computed Tomographic ◽  
Fracture Patterns ◽  
The Mean

Abstract Background: The management of intra-articular calcaneal fractures (ICFs) still faces a challenge. Available research about the anatomic patterns of ICFs is lacking. We aimed to define the pattern of ICFs by a three-dimensional (3D) mapping and determine whether there are consistent fracture patterns and comminution zones. Methods: 67 patients of ICFs with available computed tomographic (CT) scans were identified. The calcaneal fractures fragments on CT were multiplanar reconstructed and virtually reduced. 3D heat mapping was subsequently created by graphically superimposing all fracture lines onto a standard calcaneal template. Mapping of fracture lines and comminution zones in both the axial and sagittal planes were performed. Results: The cohort included 26 (38.8%) left calcaneal fractures, 27 (40.30%) right calcaneal fractures, and 14 (20.9%) cases with bilateral fractures. Comminuted fractures accounted for 92.5% of all fractures. Sagittal 3D mapping demonstrated that fracture lines were concentrated in the critical angle of Gissane and extended posteriorly to the rear of the tuberosity of the lateral wall and the anterior of the medial process of the calcaneus tuberosity but with more significant variation in the medial wall. The mean angle of fracture lines concerning the long axis of the calcaneal (LAC) was 29.1°and 19.2° in the lateral wall and medial wall, respectively. Axial 3D mapping demonstrated that fracture lines were primarily concentrated in the area anterior to the posterior joint facet and extended along the posterior joint facet and calcaneus sulcus to the posteriorly of the tuberosity. The mean angle of fracture lines concerning the LAC was 11° in the axial wall. 3D mapping demonstrated that the comminution zones are closely related to the internal structure and fracture mechanism. Conclusion: The data presented have elucidated there are consistent characteristic fracture patterns and comminution zones for ICFs. This study provides visual guidelines to understand fracture morphology, which may assist with fracture classification, preoperative planning, fixation concepts development, and internal structure analysis.

scholarly journals Three-dimensional distribution of CT attenuation in the lumbar spine pedicle wall

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomoyo Y. Irie ◽  
Tohru Irie ◽  
Alejandro A. Espinoza Orías ◽  
Kazuyuki Segami ◽  
Norimasa Iwasaki ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Age Groups ◽  
Three Dimensional ◽  
Hounsfield Unit ◽  
Lateral Wall ◽  
Ct Attenuation ◽  
Dimensional Distribution ◽  
The Mean ◽  
Pedicle Wall

AbstractThis study investigated in vivo the three-dimensional distribution of CT attenuation in the lumbar spine pedicle wall measured in Hounsfield Unit (HU). Seventy-five volunteers underwent clinical lumbar spine CT scans. Data was analyzed with custom-written software to determine the regional variation in pedicle wall attenuation values. A cylindrical coordinate system oriented along the pedicle’s long axis was used to calculate the pedicular wall attenuation distribution three-dimensionally and the highest attenuation value was identified. The pedicular cross-section was divided into four quadrants: lateral, medial, cranial, and caudal. The mean HU value for each quadrant was calculated for all lumbar spine levels (L1–5). The pedicle wall attenuation was analyzed by gender, age, spinal levels and anatomical quadrant. The mean HU values of the pedicle wall at L1 and L5 were significantly lower than the values between L2–4 in both genders and in both age groups. Furthermore, the medial quadrant showed higher HU values than the lateral quadrant at all levels and the caudal quadrant showed higher HU values at L1–3 and lower HU values at L4–5 than the cranial quadrant. These findings may explain why there is a higher incidence of pedicle screw breach in the pedicle lateral wall.

Computed tomographic study of safe implantation corridors in rabbit lumbar vertebrae

2017 ◽  
Vol 30 (05) ◽  
pp. 357-363 ◽  
Author(s):  
Tisha Harper ◽  
Stephen Joslyn ◽  
Julia Whittington ◽  
Devon Hague ◽  
Mark Mitchell ◽  
...  
Keyword(s):  
Computed Tomography ◽  
New Zealand ◽  
Three Dimensional ◽  
Lumbar Vertebrae ◽  
Bone Stock ◽  
Computed Tomographic ◽  
Mean Width ◽  
Entry Points ◽  
New Zealand White Rabbits ◽  
The Mean

Summary Objectives: A study was performed to evaluate the lumbar vertebrae of domestic rabbits using computed tomography (CT) in order to identify safe corridors for implant insertion. Methods: Computed tomography imaging of 20 adult New Zealand white rabbits was evaluated using three-dimensional multi -planar reconstruction, and safe corridors were determined. Following corridor determination, implant placement was performed, and imaging was repeated. Results: The cranial and caudal endplates contained the majority of the vertebral bone stock, and were an average of 3.14 and 3.30 mm in length, respectively. The mean safe corridor angle was 62.9 degrees (range: 58.8–66.7), and the mean width of the corridor was 2.03 mm (range: 1.60– 2.07). Post-placement imaging revealed that 35% of the pins demonstrated errors of placement, most commonly canal impingement. Conclusions: The results of the corridor evaluation indicate that an insertion angle of approximately 60 degrees relative to the sagittal midline is appropriate for implant insertion in the lumbar vertebrae of New Zealand white rabbits. Additionally, due to the hourglass shape of rabbit vertebrae, the endplates provide maximal bone stock for implant purchase, so insertion should be attempted in these regions. However, the high percentage of errors in placement indicate the need to more clearly define entry points to access the canal, and highlight the challenges of appropriate placement in the small bones of rabbits.

scholarly journals Perpendicular drill bit alignment provides a practical guidance to determine the appropriate suture anchor insertion angle during acetabular labral repair

2021 ◽  
Author(s):  
Abdul Veli Ismailoglu ◽  
Omer Ozdogmus ◽  
Muhammed Ilkay Karaman ◽  
Asim Kayaalp ◽  
Baris Kocaoglu
Keyword(s):  
Suture Anchor ◽  
Arthroscopic Surgery ◽  
Three Dimensional ◽  
Safety Margin ◽  
Reference Line ◽  
Labral Repair ◽  
Drill Bit ◽  
Computed Tomographic ◽  
The Mean ◽  
Acetabular Rim

ABSTRACT The safe acetabular rim angle is an anatomical measurement used to determine the safety margin when inserting suture anchors. The purpose of the present study was to find out whether aligning the drill bit perpendicularly during arthroscopic surgery can provide a reference point for determining an appropriate angle to facilitate the suture anchor insertion and to prevent extra- and intra-articular perforations. One hundred computed tomographic hips were used to reconstruct three-dimensional acetabular hip models. Each model was radially sectioned at the 4 o’clock, 3 o’clock and anterior inferior iliac spine (AIIS) positions (that corresponded mainly to the 2:20 clock position). A perpendicular reference line, representing a perpendicular drill bit alignment, was drawn for each position within the acetabular model, and its relation to the safe acetabular rim angle was measured. The length of the perpendicular reference line and the effect of gender on measurements were also evaluated. The mean safe acetabular rim angle at the 3 o’clock position was significantly smaller compared to other clock positions (P < 0.001). The perpendicular reference line was located out of the safe acetabular rim angle in 28 cases (%28), mostly in female acetabula at the 3 o’clock position, and relative to the perpendicular reference line the required minimal angle was 4° ± 2.3° to place the anchor in the safe acetabular rim angle to avoid extra-articular perforation. The perpendicular reference line was shortest at the 3 o’clock position, and its mean length was shorter in female acetabula at all clock positions (P < 0.001). Aligning the drill bit perpendicular to the acetabular opening plane during an arthroscopic anchor placement is a practical way to estimate and target the position of the safe acetabular rim angle to avoid anchor perforations. Based on measurements from a perpendicularly aligned drill bit, the drill bit should be directed towards the joint minimally by 4° to avoid extra-articular perforations and maximally by 30° to avoid intra-articular perforations.

During forearm rotation the three-dimensional ulnolunate distance is affected more by translation of the ulnar head than change in ulnar variance

2018 ◽  
Vol 44 (5) ◽  
pp. 517-523
Author(s):  
Seung-Han Shin ◽  
Yong-Suk Lee ◽  
Keun-Young Choi ◽  
Dai-Soon Kwak ◽  
Yang-Guk Chung
Keyword(s):  
Linear Relationship ◽  
Three Dimensional ◽  
Ulnar Variance ◽  
Forearm Rotation ◽  
Level Of Evidence ◽  
Positive Linear Relationship ◽  
Computed Tomographic ◽  
Ulnar Head ◽  
The Mean

Ulnolunate abutment has been thought to be aggravated by pronation because of an increase in ulnar variance. We hypothesized that the ulnolunate distance might be greater in pronation because the ulnar head is dorsally translated. Twenty-one three-dimensional reconstructions of computed tomographic scans of wrists taken in supination and pronation were investigated. The ulnolunate distance was measured in each position, and the change in ulnolunate distance from supination to pronation was calculated. The changes in ulnar variance from supination to pronation and the amount of translation of the ulnar head were measured directly by superimposing three-dimensional reconstructions. The mean ulnolunate distance in pronation was significantly greater than in supination. There was no significant correlation between the changes in ulnolunate distance and in the ulnar variance. The change in ulnolunate distance had a significant positive linear relationship with the amount of translation of the ulnar head. The change in ulnolunate distance during forearm rotation is determined by the amount of translation of the ulnar head rather than by change in ulnar variance. Level of evidence: IV

Repeatability of Three-Dimensional Computed Tomographic Volumetric Measurement of Lumbosacral Intervertebral Foramina in German Shepherd Dogs

2018 ◽  
Vol 31 (05) ◽  
pp. 339-343 ◽  
Author(s):  
Stefan Gordon ◽  
Janis Bridges ◽  
Susan Tomlin ◽  
Angela Hartman ◽  
Andrew Worth
Keyword(s):  
Three Dimensional ◽  
Clinical Signs ◽  
Volumetric Analysis ◽  
Lumbosacral Junction ◽  
Volumetric Measurement ◽  
German Shepherd ◽  
Computed Tomographic ◽  
Volume Measurements ◽  
The Mean ◽  
Intervertebral Foramina

Objectives This article determines the repeatability of a recently reported method of volumetric measurement of the lateral intervertebral neurovascular foramina at the lumbosacral junction in German shepherd dogs. Materials and Methods Batch files including the intervertebral neurovascular foramina were derived from previously obtained computed tomography studies of the extended lumbosacral junction of 20 German shepherd dogs and converted into volume datasets. Three observers independently performed five measurements of the left and right lumbosacral intervertebral neurovascular foramina in each dog, using an Extended Brilliance Workstation (Phillips, The Netherlands) to generate a volume of the lumbosacral intervertebral foramina in cubic millimetres, as described by Worth and colleagues in 2017. The inter-observer repeatability of the mean of the five-volume measurements (40 foramina) was assessed using the Bland–Altman limits of agreement method. One observer, blinded to the previous measurements, repeated the volumetric analysis on 20 lumbosacral intervertebral foramina for an assessment of intra-observer repeatability using the same statistical methods. Results This method of volumetric analysis showed good intra- and inter-observer repeatability with 95% of paired comparisons falling within two standard deviations of the mean difference between them. Clinical Significance This method of measuring the volume of the lumbosacral intervertebral neurovascular foramina is repeatedly reliable and may be a useful tool when testing the effects of motion and disease on the lumbosacral junction, and could help guide surgical intervention when foraminal narrowing is implicated in the clinical signs.

scholarly journals The importance of medial wall stabilization in sinus-tarsi approach to treat Sanders type II and III calcaneus fractures

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0003
Author(s):  
Zhongmin Shi
Keyword(s):  
Joint Stiffness ◽  
Deep Infection ◽  
Medial Wall ◽  
Type Ii ◽  
Calcaneal Fractures ◽  
Sinus Tarsi ◽  
Sinus Tarsi Approach ◽  
The Mean ◽  
Calcaneus Fractures

Category: Trauma Introduction/Purpose: The aim of this study was to assess the clinical outcomes of medial wall stabilization in sinus-tarsi approach to treat Sanders type II and III calcaneus fractures. Methods: In this retrospective study, a total of 38 patients (32 men and 6 women) with 38 displaced intra-articular calcaneal fractures were included. A modified sinus tarsi approach was used to reduce and stabilize the posterior facet using rafting technique with mini-fragment locking plate and multiple sagittal screws were added percutaneously to stabilize the calcaneal body and to control rotation. Preoperative and postoperative Böhler’s and Gissane angle were compared, American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scores and SF-36 scores were used to evaluate the final outcomes, and the complications were also recorded. Results: The mean duration of follow-up was 17.4 months. The mean preoperative Böhler’s angle (13.4 ± 3.4°), Gissane angle (88.1 ± 7.6°) were significantly increased (P < 0.05) at final follow-up (25.5 ± 5.6°, 116.2 ± 7.5°, respectively). Complications included 9 cases of moderate subtalar joint stiffness. There were 2 cases with wound edge necrosis, but there was no superficial or deep infection, or nerve injury was observed in these patients. Conclusion: The application of minimally invasive rafting technique with medial wall stabilization is an effective option for displaced intra-articular calcaneal fractures.

scholarly journals Three-Dimensional Mapping of Medial Wall in Unstable Pertrochanteric Fractures

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yingqi Zhang ◽  
Yeqing Sun ◽  
Shenghui Liao ◽  
Shimin Chang
Keyword(s):  
Internal Fixation ◽  
Three Dimensional ◽  
Morphological Characteristics ◽  
Medial Wall ◽  
Pertrochanteric Fractures ◽  
Computed Tomographic ◽  
Three Dimensional Mapping ◽  
Mean Width ◽  
Mapping Technology ◽  
Dimensional Mapping

Objective. Unstable pertrochanteric fractures are usually treated with internal fixation, and the integrity of the anteromedial cortex is an important factor for stability and healing. In this study, we described and analyzed the three-dimensional mapping technology and morphological characteristics of pertrochanteric fractures. Methods. Fifty-nine pertrochanteric fractures (OTA/AO 2007 types 31A2) were retrospectively reviewed. Computed tomographic (CT) images for all fractures were superimposed on a standard template. Medial wall integrity was analyzed, and three-dimensional fracture maps were created. Results. Pertrochanteric fractures always have a posterior defect in the medial cortex. The mean width of the defect, in our study, was 21.5 mm (SD: 6.1 mm, range: 10–40 mm), 56.3% (SD: 13.7%, range: 27.5-100%). Bone segments that contact by the anteromedial cortex were 16.5 mm (SD: 5.3 mm, range: 0-29 mm). Conclusion. The integrity of the anteromedial cortex should be considered during internal fixation of femoral trochanteric fractures. These morphological characteristics could be used to form postoperative cortical contact and improve stability of the fixation. Three-dimensional mapping technology can help establish a typical fracture model, thereby improving doctors’ understanding of fracture characteristics.

X-ray microtomography

1988 ◽  
Vol 46 ◽  
pp. 998-999
Author(s):  
H.W. Deckman ◽  
B.F. Flannery ◽  
J.H. Dunsmuir ◽  
K.D' Amico
Keyword(s):  
Computed Tomography ◽  
Internal Structure ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Tissue Structure ◽  
Individual Element ◽  
X Ray ◽  
Non Invasive ◽  
Panoramic Imaging ◽  
Three Dimensional Images

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.

ROC Analysis of Three Perfusion Display Options for ECG-gated Perfusion SPECT in Severe CAD

1999 ◽  
Vol 38 (06) ◽  
pp. 172-177
Author(s):  
H. Bailer ◽  
Marianne Gwechenberger ◽  
Martha Pruckmayer ◽  
A. Staudenherz ◽  
G. Kronik ◽  
...  
Keyword(s):  
Roc Analysis ◽  
Lateral Wall ◽  
Visual Assessment ◽  
3D Mapping ◽  
Operating Characteristics ◽  
Gated Perfusion Spect ◽  
Perfusion Spect ◽  
Coronary Stenoses ◽  
Definition Of ◽  
Valve Plane

Summary Aim: The simultaneous computation and display of wall motion and perfusion patterns in a single 3D ventricular model would considerably ease the assessment of ECG-gated Tc-99m-sestamibi SPECT, yet the effect on the accuracy of allocating regional perfusion has so far not been validated. Methods: 3D perfusion mapping (3D Perfusion/Motion Map Software) was compared to the visual assessment of ungated tomographic slices and polar perfusion mapping (Cedars-Sinai PTQ) by correlation analysis and receiver operating characteristics (ROC) analysis at different cut-off levels for coronary stenoses in 50 patients (11 single-, 22 two-, 16 three-vessel disease). Ungated SPECT data were obtained by adding the intervals prior to reconstruction and displaying conventional tomographic slices. All display options were visually assessed in 8 ventricular segments according to a 4-point scoring system and compared to the graded results of coronary angiography. Results: All three display options showed a comparable diagnostic performance for the detection of severe stenoses. The diagnostic gain for the detection of stenoses above 59% was highest for ungated tomographic slices, followed by ungated polar mapping and 3D mapping. Regional assessment revealed a limited performance of 3D mapping in the proximal anterior and distal lateral wall. Polar mapping showed a balanced regional performance. Conclusion: 3D Perfusion mapping provides comparable information to conventional display options with the highest diagnostic strength in severe stenoses. Further improvement of the algorithm is needed in the definition of the valve plane.

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