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.

Three-Dimensional Computed Tomography in the Diagnosis of Vertebral Column Pathological Conditions

Neurosurgery ◽  
1987 ◽  
Vol 21 (2) ◽  
pp. 186-192 ◽  
Author(s):  
Mark N. Hadley ◽  
Volker K. H. Sonntag ◽  
Rob M. Amos ◽  
John A. Hodak ◽  
Lynda J. Lopez
Keyword(s):  
Computed Tomography ◽  
Vertebral Column ◽  
Three Dimensional ◽  
Lumbar Vertebrae ◽  
Diagnostic Technique ◽  
Craniovertebral Junction ◽  
Diagnosis And Treatment ◽  
Computed Tomographic ◽  
Pathological Conditions ◽  
Valuable Adjunct

Abstract Three-dimensional computed tomographic scanning is a valuable adjunct in the diagnosis and treatment of disease processes involving the spine. We present our experience with this noninvasive radiological diagnostic technique in 32 patients with vertebral column abnormalities ranging from craniovertebral junction disorders to fractures of lumbar vertebrae. The three-dimensional CT images often demonstrate pathological conditions and occult lesions that are not adequately defined by conventional radiographic means.

Bone-mounted Miniature Robotic Guidance for Pedicle Screw and Translaminar Facet Screw Placement: Part 2—Evaluation of System Accuracy

2007 ◽  
Vol 60 (suppl_2) ◽  
pp. ONS-129-ONS-139 ◽  
Author(s):  
Daisuke Togawa ◽  
Mark M. Kayanja ◽  
Mary K. Reinhardt ◽  
Moshe Shoham ◽  
Alin Balter ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Three Dimensional ◽  
Contralateral Side ◽  
X Rays ◽  
Average Deviation ◽  
Computed Tomographic ◽  
Entry Points ◽  
External Frame ◽  
K Wires ◽  
Preoperative Plan

Abstract Objective: To evaluate the accuracy of a novel bone-mounted miniature robotic system for percutaneous placement of pedicle and translaminar facet screws. Methods: Thirty-five spinal levels in 10 cadavers were instrumented. Each cadaver's entire torso was scanned before the procedure. Surgeons planned optimal entry points and trajectories for screws on reconstructed three-dimensional virtual x-rays of each vertebra. Either a clamp or a minimally invasive external frame was attached to the bony anatomy. Anteroposterior and lateral fluoroscopic images using targeting devices were obtained and automatically registered with the virtual x-rays of each vertebra generated from the computed tomographic scan obtained before the procedure. A miniature robot was mounted onto the clamp and external frame and the system controlled the robot's motions to align the cannulated drill guide along the planned trajectory. A drill bit was introduced through the cannulated guide and a hole was drilled through the cortex. Then, K-wires were introduced and advanced through the same cannulated guide and left inside the cadaver. The cadavers were scanned with computed tomography after the procedure and the system's accuracy was evaluated in three planes, comparing K-wire positions with the preoperative plan. A total of fifty-five procedures were evaluated. Results: Twenty-nine of 32 K-wires and all four screws were placed with less than 1.5 mm of deviation; average deviation was 0.87 ± 0.63 mm (range, 0-1.7 mm) from the preoperative plan in this group. Sixteen of 19 K-wires were placed with less than 1.5 mm of deviation. There was one broken and one bent K-wire. Another K-wire was misplaced because of collision with the previously placed wire on the contralateral side of the same vertebra because of a mistake in planning, resulting in a 6.5-mm deviation. When this case was excluded, average deviation was 0.82 ± 0.65 mm (range, 0-1.5 mm). Conclusion: These results verify the system's accuracy and support its use for minimally invasive spine surgery in selected patients.

scholarly journals Radiographic Measurement of Cochlear in Sudanese Population using High Resolution Computed Tomography (HRCT)

2021 ◽  
Vol 29 (2) ◽  
Author(s):  
Lubna Bushara ◽  
Mohamed Yousef ◽  
Ikhlas Abdelaziz ◽  
Mogahid Zidan ◽  
Dalia Bilal ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Hearing Loss ◽  
High Resolution ◽  
Temporal Bone ◽  
Healthy Subjects ◽  
Cochlear Nerve ◽  
High Resolution Computed Tomography ◽  
Mean Width ◽  
The Mean ◽  
The Right

This study aimed to determine the measurements of the cochlea among healthy subjects and hearing deafness subjects using a High Resolution Computed Tomography (HRCT). A total of 230 temporal bone HRCT cases were retrospectively investigated in the period spanning from 2011 to 2015. Three 64-slice units were used to examine patients with clinical complaints of hearing loss conditions at three Radiology departments in Khartoum, Sudan. For the control group (A) healthy subjects, the mean width of the right and left cochlear were 5.61±0.40 mm and 5.56±0.58 mm, the height were 3.56±0.36 mm and 3.54±0.36 mm, the basal turn width were 1.87±0.19 mm and 1.88 ±0.18 mm, the width of the cochlear nerve canal were 2.02±1.23 and 1.93±0.20, cochlear nerve density was 279.41±159.02 and 306.84±336.9 HU respectively. However, for the experimental group (B), the mean width of the right and left cochlear width were 5.38±0.46 mm and 5.34±0.30 mm, the height were 3.53±0.25 mm and 3.49±0.28mm, the basal turn width were 1.76±0.13 mm, and 1.79±0.13 mm, the width of the cochlear nerve canal were 1.75±0.18mm and 1.73±0.18mm, and cochlear nerve density were 232.84±316.82 and 196.58±230.05 HU, respectively. The study found there was a significant difference in cochlea’s measurement between the two groups with a p-value < 0.05. This study had established baseline measurements for the cochlear for the healthy Sudanese population. Furthermore, it found that HRCT of the temporal bone was the best for investigation of the cochlear and could provide a guide for the clinicians to manage congenital hearing loss.

Diagnosis and t-staging of gastric cancer: comparison of standard computed tomography and computed-tomographic pneumogastrography

2021 ◽  
Vol 23 (2) ◽  
pp. 99-106
Author(s):  
Inna D. Amelina ◽  
Lev N. Shevkunov ◽  
Aleksey M. Karachun ◽  
Alexander E. Mikhnin ◽  
Denis V. Nesterov
Keyword(s):  
Gastric Cancer ◽  
Computed Tomography ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Subtotal Resection ◽  
Standard Protocol ◽  
Computed Tomographic ◽  
T Stage ◽  
Significant Difference ◽  
Virtual Gastroscopy

The advantages of computed tomographic pneumogastrography with the possibility of three-dimensional visualization and virtual gastroscopy in diagnosing gastric cancer are considered. The study included 479 patients with histologically diagnosed gastric cancer who were treated at the National Medical Research Center of Oncology named after N.N. Petrov from 2011 to 2018. 232 patients received preoperative chemotherapy. All patients underwent surgery: 70 in the volume of endoscopic dissection, 40 proximal subtotal resection, 166 distal subtotal resection, 203 gastrectomy. All patients at the preoperative stage underwent staging computed tomography on a 64-slice X-ray computed tomograph: 208 patients underwent computed tomography according to the standard protocol without targeted preparation of the stomach for the study, 271 patients with targeted preparation of the stomach for the study according to the computed tomographic pneumogastrography protocol. The sensitivity of the computed tomography in assessing the T-stage was assessed by comparison with pathomorphological data. Of the 208 patients who underwent computed tomography according to the standard protocol, a gastric cancer was detected in 111 (53.4%), out of 271 patients who underwent computed tomography pneumogastrography, a gastric cancer was detected in 267 (98.52%), which is a statistically significant difference in comparing computed tomography methods (Pearson, 144.223, df = 1; p 0.001). There are statistically significant differences when comparing computed tomography according to the standard protocol and computed tomographic pneumogastrography in detecting gastric cancer for all tumor categories: T/yT1 8.2 and 94.4% (Pearson, 99.205, df = 1; p 0.001), T/yT2 47.8 and 100% (Pearson, 24.681, df = 1; p 0.001), T/yT3 72.3 and 100% (Pearson, 33.114, df = 1; p 0.001), T/yT4 90.0 and 100% (Pearson, 4.789, df = 1; p = 0.029) respectively. There are also statistically significant differences when comparing the sensitivity of computed tomography according to the standard protocol and computed tomographic pneumogastrography in determining tumor invasion for all tumor categories: T/yT1 0 and 69.4% (Pearson, 67.880, df = 1; p 0.001), T/yT2 26.1 and 71.1% (Pearson, 11.666, df = 1; p 0.001), T/yT3 32.9 and 84.6% (Pearson, 54.900, df = 1; p 0.001), T/yT4 73.3 and 95.7% (Pearson, 7.916, df = 1; p = 0.005) respectively. In general, the sensitivity of the computed tomography according to the standard protocol for determining the T-stage of gastric cancer was 28.4%, computed tomographic pneumogastrography 77.1% (Pearson, 113.505, df = 1; p 0.001). Computed tomographic pneumogastrography with the possibility of three-dimensional visualization and virtual gastroscopy significantly increases the indicators of the effectiveness of diagnosing gastric cancer both early forms (category T1) and with deeper invasion (categories T2T4), demonstrates high sensitivity in determining T/yT-stages.

scholarly journals Application of 3D Computed Tomography Reconstruction Images to Assess the Thickness and Dimensions of the Posterior Palatal Seal Area

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Soeun Lim ◽  
Seoung-Jin Hong ◽  
Joo-Young Ohe ◽  
Janghyun Paek
Keyword(s):  
Computed Tomography ◽  
3D Model ◽  
Three Dimensional ◽  
Ct Images ◽  
Anterior Border ◽  
Lateral Direction ◽  
Mean Dimension ◽  
The Mean ◽  
The Right ◽  
Palatal Mucosa

Few studies have been reported on the scientific measurements of the thickness and dimensions of the posterior palatal seal (PPS) area. The purpose of this study is to measure and analyze the thickness of palatal mucosa by using a three-dimensional (3D) model reconstructed with computed tomography (CT) images and to present objective values by identifying the PPS area. The CT images were reconstructed as a 3D model by separating the maxillary palate mucosa and teeth. Each reconstructed model was analyzed and the thickness was measured at 93 crossing points of each divided plane. The dimension of the PPS area was measured and the right and left dimensions of the PPS area were compared. The thickness of the palatal mucosa was thicker toward the posterior area. The thickness increased in the lateral direction and decreased again. In the PPS area, the mean dimension between the rearmost of anterior border and the most posterior line was 2.19 mm and the mean dimension between the forefront of anterior border and the most posterior line was 5.19 mm in the right side and 5.16 mm in the left side. The mean dimension from the center of the palate to the right most forward point was 6.85 mm, and the left was 7.36 mm. The new measurement method of palatal mucosal thickness is noninvasive, accurate, and easy to store and study, so it can be used effectively in planning and manufacturing the maxillary complete denture in the digital workflows.

scholarly journals Sexual maturity in rabbits defined by the physical and chemical characteristics of the semen

1978 ◽  
Vol 12 (1) ◽  
pp. 37-39 ◽  
Author(s):  
M. Macari ◽  
C. R. Machado
Keyword(s):  
New Zealand ◽  
Sexual Maturity ◽  
Chemical Characteristics ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Mean Values ◽  
New Zealand White Rabbits ◽  
The Mean ◽  
Physical And Chemical ◽  
Artificial Vagina

Semen was collected weekly from New Zealand white rabbits from the 1st positive mounting test to 43 weeks of age by means of an artificial vagina. The mean values of the results obtained in the 1st and 20th collection weeks were respectively: volume (ml) 0·61 ± 0·30 and 0·70 ± 0·19; pH 7·22 ± 0·50 and 7·19 ± 0±15; concentration (sperm/mm3 x 103) 750 ± 207 and 381 ± 90; fructose (mg/l00 ml) 117 ± 58 and 203 ± 121; citric acid (mg/l00 ml) 256 ± 90 and 200 ± 97; sodium ions (mEq/l) 133 ± 31 and 163 ± 46; potassium ions (mEq/l) 40 ± 21 and 29 ± 14. On the basis of these results, New Zealand white rabbits reach sexual maturity by 6 months of age.

Three-dimensional Computed Tomographic Cranial Base Measurements for Improvement of Surgical Approaches to the Petrous Carotid Artery and Apex Regions

Neurosurgery ◽  
2001 ◽  
Vol 49 (2) ◽  
pp. 342-353 ◽  
Author(s):  
Alan T. Villavicencio ◽  
Jean-Christophe Leveque ◽  
Ketan R. Bulsara ◽  
Allan H. Friedman ◽  
Linda Gray
Keyword(s):  
Computed Tomography ◽  
Carotid Artery ◽  
Three Dimensional ◽  
Internal Auditory Canal ◽  
Cranial Base ◽  
Petrous Apex ◽  
Surgical Approaches ◽  
Tomographic Images ◽  
Computed Tomographic ◽  
Preoperative Information

Abstract OBJECTIVE The bony and vascular anatomic features in the region of the petrous apex can vary significantly. These variations affect the operative view obtained via extended subtemporal or anterior transpetrosal approaches to cranial base lesions for individual patients. The goal of this study was to evaluate three-dimensional computed tomography as a means of obtaining detailed preoperative anatomic information regarding bony and vascular landmarks and spatial relationships in the region of the petrous carotid artery and petrous apex. METHODS We radiographically studied 15 patients (30 sides), using 0.8- to 1-mm-thick, reconstructed, computed tomographic images. Special attention was given to the course of the petrous carotid artery. RESULTS The petrous carotid artery was located lateral to the trigeminal impression. The size of the petrous apex medial to the horizontal petrous carotid artery was observed to be variable. The width of bone from the trigeminal impression to the wall of the internal auditory canal averaged 9.6 mm (range, 5.2–16.1 mm). A variable amount of bone overlying the internal auditory canal (4.5 mm) was also present. Multiple other relationships among key landmarks were quantified. CONCLUSION There is significant variability in the anatomic features of the petrous apex among patients. For each patient, detailed preoperative information regarding the amount of bone to be removed during a cranial base procedure can be obtained using three-dimensional computed tomography. This information may be critical for determination of the amount of extra exposure that can be achieved via an anterior petrosectomy for each patient.

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