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Measurement of pedicle width as conducted on an axial CT scan (a) at the middle height of the pedicle (b).
Source publication
The aim of this study was to compare pedicle dimensions in degenerative lumbar spinal stenosis (DLSS) with those in the general population. A retrospective computerized tomography (CT) study for lumbar vertebrae (L1 to L5) from two sample populations was used. The first included 165 participants with symptomatic DLSS (age range: 40-88 years, sex ra...
Similar publications
The aim of this study is to determine the sagittal inclination of lumbar spinous processes (SPs) in individuals with degenerative lumbar spinal stenosis (DLSS). It is a retrospective computerized tomography (CT) study including 345 individuals divided into two groups: control (90 males, 90 females) and stenosis (80 males and 85 females. The SP incl...
Citations
... The average pedicle width of normal Israel population(L3:8-9.7 mm;L4:9.8-11.5 mm; L5:14.5-16 mm) from a cross-sectional retrospective study is smaller than those in degenerative lumbar spinal stenosis (DLSS) population [33]. The transverse pedicle isthmus width from [18]. ...
To investigate a novel approach for establishing the transverse pedicle angle (TPA) of the lower lumbar spine using preoperative digital radiography (DR). Computed Tomography (CT) datasets of the lower lumbar were reconstructed using MIMICS 17.0 software and then imported into 3-matic software for surgical simulation and anatomical parameter measurement. A mathematical algorithm of TPA based on the Pythagorean theorem was established, and all obtained data were analyzed by SPSS software. The CT dataset from 66 samples was reconstructed as a digital model of the lower lumbar vertebrae (L3-L5), and the AP length/estimated lateral length for L3 between the right and left sides was statistically significant (P = 0.015, P = 0.005). The AP length of the right for L4 was smaller than that of the left after a paired t test was executed (P = 0.006). Both the width of the pedicle and the length of the pedicle (P2C1) were consistent with TPA (L3<L4<L5). There were no significant differences in TAN-TPA and DR-TPA compared with real TPA. The ICCs for the real TPA and DR-TPA within L3 showed good reliability, and the ICCs for the real TPA and DR-TPA within both L4 and L5 showed moderate reliability. Our novel approach can be considered a reliable way to determine the transverse pedicle angle from routine DR, and the width and length of the pedicle within lumbar DR should be considered to determine the length and trajectory of the screw during preoperative planning.
... All the CT measurements were taken from L1 to S1 levels and included the vertebral body diameters (width, length and height), bony canal dimensions such as anterior-posterior (AP), medio-lateral, and cross-section area (CSA) [8]. We also addressed the facets orientation and tropism [27], pedicle width and height [28], spinous process orientation [29], laminar inclination and inter-laminar angle [8]. Spine pathology such as vacuum phenomenon, intervertebral disc height, and the presence of Schmorl's nodes [30,31] were also recorded. ...
... We evaluated the performance of RF classifier by the following measures: (1) sensitivity (SE) which represent the true positive (TP) rate, (2) specificity (SP) which represents the true negative (TN) rate (complement of sensitivity), and (3) precision (PR) which represents the ability to correctly predict the positive target condition to the total [28]. In addition, we assessed the accuracy (ACC) which represents the classifier ability to predict the target condition correctly, and the F-measure that illustrates the classifier ability to predict the target condition correctly (compared to ACC, it is more accurate in cases of imbalanced data set, since it considers both PR and SE) [35]. ...
Background:
Degenerative lumbar spinal stenosis (DLSS) is the most common spine disease in the elderly population. It is usually associated with lumbar spine joints/or ligaments degeneration. Machine learning technique is an exclusive method for handling big data analysis; however, the development of this method for spine pathology is rare. This study aims to detect the essential variables that predict the development of symptomatic DLSS using the random forest of machine learning (ML) algorithms technique.
Methods:
A retrospective study with two groups of individuals. The first included 165 with symptomatic DLSS (sex ratio 80 M/85F), and the second included 180 individuals from the general population (sex ratio: 90 M/90F) without lumbar spinal stenosis symptoms. Lumbar spine measurements such as vertebral or spinal canal diameters from L1 to S1 were conducted on computerized tomography (CT) images. Demographic and health data of all the participants (e.g., body mass index and diabetes mellitus) were also recorded.
Results:
The decision tree model of ML demonstrate that the anteroposterior diameter of the bony canal at L5 (males) and L4 (females) levels have the greatest stimulus for symptomatic DLSS (scores of 1 and 0.938). In addition, combination of these variables with other lumbar spine features is mandatory for developing the DLSS.
Conclusions:
Our results indicate that combination of lumbar spine characteristics such as bony canal and vertebral body dimensions rather than the presence of a sole variable is highly associated with symptomatic DLSS onset.
... There are however, some confounders to the association of the PII and the screw angulation, which includes the depth of the actual posterior superior iliac spine and its relationship to the entry point of the screw of the S1 pedicle as a longer length would likely result in a less angulated screw [7]. Consideration should also be given to the natural variation in pedicle width in each individual patient, as demonstrated in other segments of the spine [11], as well as compromises required to align the screw heads to connect the rods. Furthermore, other patient factors, such as age, underlying pathology, degree of osteopaenia/ osteoporosis, indication for fixation and total length of the fixation construct, and others, will likely have profound influences on the strength and reliability of a construct, beyond that of angulation [9,10]. ...
Introduction:
Surgical fixation is widely practised in the management of spinal deformity. S1 screws are commonly incorporated in lumbosacral fusions and can be performed in both open and percutaneous techniques. However, their entry point is determined by the position of the pedicle as well as the posterior iliac interval (PII), as it creates an impedance for screw angulation. A wider angle screw has the potential to achieve a greater length and thus strength versus a narrow screw angle insertion due to risk of anterior breach.
Methods:
A retrospective analysis of 50 consecutive patients between July 2018 andDecember 2021 undergoing lumbo-sacral fusion with include S1 screw insertion from a single institution and surgeon. The age, screw angles, and the posterior iliac intervals were measured.
Results:
The patients ranged from age 27 to 83 years old (mean 64.7) with a posterior iliac interval (PII) ranging from 7.76 to 12.62 cm (mean 10.24) and the average S1 screw angle on the right was 76.01 degrees (range 59.37 to 88.48) and on the left 74.37 degrees (range 59.75 to 87.47 degrees). Applying the Pearson Correlation co-efficient, a wider PII correlated with a more angulated screw entry (P < 0.05).
Conclusion:
As expected, a wider PPI is significantly associated with a more angulated S1 screw trajectory and may have implication on patient biomechanics in lumbo-sacral fusion constructs.
... 37,38 Another shortcoming of the study was the profile contour of the vertebrae, BMD, the dimensions of the pedicle, the thickness of the vertebral plate, and the length of the transverse process and spinous process were based on the highresolution CT images of a single adult healthy woman, and might not be representative of the patient population. 39,40 Third, only the axial pullout was simulated, and the screw actually experienced loads in many directions, like bending loads up and down. 13,41 A last limitation of the study was that the results based on the FEA must be verified by in vitro experiments in the future to be truly convincing. ...
Research design:
Finite element analysis based on CT images from the lumbar spine.
Objective:
Determined the pull-out strength of unsatisfactorily placed screws and repositioned screws after unsatisfactory place in lumbar spine surgery.
Background:
Pedicle screws are widely used to stabilize the spinal vertebral body. Unsatisfactory screws could lead to surgical complications, and may need to be repositioned. Screw removal and reposition, however, may decrease pull-out strength.
Methods:
We conducted a three-dimensional finite element analysis based on high-resolution CT images from a 39-years-old healthy woman. Pull-out strength was determined with the screw placed in different orientations at the same entry point (as selected by the Magerl method), as well as after removal and reposition. The material properties of the vertebral body and the screw were simulated by using grayscale values and verified data, respectively. A load along the screw axis was applied to the end of the screw to simulate the pullout.
Results:
The pull-out strength was 1840.0 N with the Magerl method. For unsatisfactorily placed screws, the pull-out strength was 1500.8 N at 20% overlap, 1609.6 N at 40% overlap, 1628.9 N at 60% overlap, and 1734.7 N at 80% overlap with the hypothetical screw path of the Magerl method. For repositioned screws, the pull-out strength was 1763.6 N, with 20% overlap, 1728.3 N at 40% overlap, 1544.0 N at 60% overlap, and 1491.1 N at 80% overlap with the original path. Comparison of repositioned screw with unsatisfactorily placed screw showed 14.04% decrease in pull-out strength at 80% overlap, 5.21% decrease at 60% overlap, 7.37% increase at 40% overlap, and 17.51% increase at 20% overlap with the screw path of the Magerl method.
Conclusion:
Removal and reposition increased the pull-out strength at 20% and 40% overlap, but decreased the pull-out strength at 60% and 80% overlap. For clinical translation, we recommend removal and reposition of the screw when the overlap is in the range of 20%-40% or less. In vitro specimen studies are needed to verify these preliminary findings.
... All the CT measurements were taken from L1 to S1 levels and included the vertebral body diameters (width, length and height), bony canal dimensions such as anterior-posterior (AP), medio-lateral, and cross-section area (CSA) [8]. We also addressed the facets orientation and tropism [28], pedicle width and height [29], spinous process orientation [30], laminar inclination and inter-laminar angle [8]. Spine pathology such as vacuum phenomenon, intervertebral disc height, and the presence of Schmorl's nodes [31,32] were also recorded. ...
... We have evaluated the performance of RF classi er by the following measures: (1) sensitivity (SE) which represent the true positive (TP) rate, (2) speci city (SP) which represents the true negative (TN) rate (complement of sensitivity), and (3) precision (PR) which represents the ability to correctly predict the positive target condition to the total [29]. In addition, we have assessed the accuracy (ACC) which represents the classi er ability to predict the target condition correctly, and the F-measure that illustrates the classi er ability to predict the target condition correctly (compared to ACC, it is more accurate in cases of imbalanced data set, since it considers both PR and SE) [36]. ...
Background
Degenerative lumbar spinal stenosis (DLSS) is the most common spine disease in the elderly population. It is usually associated with lumbar spine joints/or ligaments degeneration. Machine learning technique is an exclusive method for handling big data analysis; however, the development of this method for spine pathology is rare. This study aims to detect the essential variables that predict the development of symptomatic degenerative lumbar spinal stenosis (DLSS) using the random forest of machine learning (ML) algorithms technique.
Methods
A retrospective study with two groups of individuals. The first included 165 with symptomatic DLSS (sex ratio 80 M/85F), and the second included 180 individuals from the general population (sex ratio: 90M/90F) without lumbar stenosis symptoms. Lumbar spine measurements such as vertebral/or spinal canal diameters from L1 to S1 were conducted on computerized tomography (CT) images (Brilliance 64, Philips Medical System, Cleveland, OH). Demographic and health data of all the participants (e.g., body mass index and diabetes mellitus) were also recorded.
Results
The decision tree model of ML demonstrate that the AP diameter of the bony canal at L5 (males) and L4 (females) levels have the greatest stimulus for symptomatic DLSS (scores of 1 and 0.938). In addition, combination of these variables with other lumbar spine features is mandatory for developing the DLSS.
Conclusions
Our results indicate that combination of lumbar spine characteristics such as bony canal and vertebral body dimensions rather than the presence of a sole variable is highly associated with symptomatic DLSS onset.
... There have been many studies on the morphology and imaging of the lumbar spine in recent years, mainly comparing the differences in different ethnic, gender, and national populations [13][14][15][16][17][18][19]. Morita K et al. measured and analyzed the thoracolumbar pedicle morphology and size in 227 Japanese patients. ...
Purpose
The short rod technique (SRT) is a novel method for lumbar pedicle screw placement to reduce surgical trauma and avoid damage to the facet joint and articular surface. The core concept is to change the entry point and angle of the screw on the vertebrae at both ends in the sagittal plane to shorten the length of the longitudinal rods. The purpose of this study is to determine the sagittal screw angle (SSA) and its safe Maximum (MAX) value on each lumbar vertebra for the SRT and to observe the shortening effect on the longitudinal rods.
Methods
A total of 152 healthy adults were investigated by measuring the lumbar spine lateral view images. The SSA and MAX-SSA were measured with SRT as reference to the conventional placement technique method. The distance between the entry points of the proximal and distal vertebrae was measured to compare the changes in the length of the longitudinal rods using the two screw placement techniques.
Results
+ SSA increased from L1 to L4, and −SSA increased from L2 to L5, in which the −SSA of L2, L3, and L4 were significantly greater than those of + SSA (P < 0.05). + MAX-SSA at L1–L4 was 23.26 ± 3.54°, 23.68 ± 3.37°, 24.12 ± 3.29°, and 24.26 ± 3.42°, respectively. −MAX-SSA at L2–L5 was 36.25 ± 3.26°, 38.26 ± 3.73°, 38.62 ± 3.63° and 37.33 ± 3.31°, respectively. Theoretical reductions by calculation for the 2-segment lumbar pedicles were: L1–2: 9 mm, L2–3: 9.29 mm, L3–4: 6.23 mm, and L4–5: 7.08 mm; And the 3-segment lumbar pedicles were: L1–3: 16.97 mm, L2–4: 16.73 mm, L3–5, and 18.24 mm, respectively.
Conclusions
The application of the SRT to lumbar pedicles is a safe screw placement method that can significantly shorten the length of the used longitudinal rods.
... At the axial plane bisected the intervertebral disc level, axial facet joint angles were measured via a line drawn between the anteromedial and posterolateral of each facet joint and the other line drawn in the midsagittal plane of the vertebrae [17,18], and facet joint asymmetry is calculated each level of the lumbar. Pedicle width measurement was conducted on an axial plane parallel to the upper vertebral endplate at the middle height of the pedicle [19][20][21]. Pedicle height was measured on a sagittal plane parallel to the anteroposterior midline of a vertebral body [19][20][21]. The illustration is provided in Fig. 1. ...
... Pedicle width measurement was conducted on an axial plane parallel to the upper vertebral endplate at the middle height of the pedicle [19][20][21]. Pedicle height was measured on a sagittal plane parallel to the anteroposterior midline of a vertebral body [19][20][21]. The illustration is provided in Fig. 1. ...
PurposeTo determine and compare the performance of zero echo imaging (ZTE) with conventional MRI sequences on lumbar osseous morphology in patients suspected with lumbar degeneration with multi-slice computed tomography (MSCT) as standard reference.
Methods22 subjects with concerned lumbar degeneration were recruited. All subjects were scanned with ZTE sequence after routine conventional MR sequences on a 3.0 T system and also received MSCT examination. Image quality was assessed. The quantitative and qualitative parameters of lumbar osseous morphology on MSCT, ZTE and MRI images were evaluated by three musculoskeletal radiologists independently. Inter-reader and inter-modality reliability and the difference between the modalities were calculated.ResultsThere was no difference for the osseous parameters between modalities, including axial orientation (p = 0.444), IAD (p = 0.381), lateral recess (p = 0.370), pedicle width (p = 0.067), pedicle height (p = 0.056), and osteophyte grade (p = 0.052). The measurement of the foramina diameter was statistically different between conventional MRI and MSCT (p < 0.05) but not between the MSCT and ZTE (p = 0.660). Conventional MRI was more likely to miss cortical bone abnormalities. ZTE appeared blurrier in cortical bone than MSCT, especially in cases with severe lumbar degeneration. The inter-reader agreement between MSCT and ZTE-MRI was higher than between MSCT and conventional MRI.ConclusionsZTE-MRI could offer more cortical bone details than conventional MRI images and might be a valid alternative to CT for lumbar osseous morphology assessment to some extent.
... As compared with male patients, female patients generally have smaller pedicle dimensions, independent of age and body mass index. 39,40 Other researchers have found that a smaller pedicle increases pedicle screw breach incidence. 41 This observation, coupled with the observation that female patients generally have lower bone mineral density, 42,43 may explain why female patients are more likely to have a high-grade screw breach even when iCT-Nav is implemented. ...
Objective
Intraoperative computed tomography and navigation (iCT-Nav) is increasingly used to aid spinal instrumentation. We aimed to document the accuracy and revision rate of pedicle screw placement across many screws placed using iCT-Nav. We also assess patient-level factors predictive of high-grade pedicle breach.
Methods
Medical records of patients who underwent iCT-Nav pedicle screw placement between 2015 and 2017 at a single center were retrospectively reviewed. Screw placement accuracy was individually assessed for each screw using the 2-mm incremental grading system for pedicle breach. Predictors of high-grade (> 2 mm) breach were identified using multiple logistic regression.
Results
1,400 pedicle screws were placed in 208 patients undergoing cervicothoracic (29; 13.9%), thoracic (30; 14.4), thoracolumbar (19; 9.1%) and lumbar (130; 62.5%) surgeries. iCT-Nav afforded high-accuracy screw placement, with 1,356 out of 1400 screws (96.9%) being placed accurately. 37 pedicle screws (2.64%) were revised intraoperatively during the index surgery across 31 patients, with no subsequent returns to the operating room because of screw malpositioning. After correcting for potential confounders, males were less likely to have a high-grade breach (OR=0.21 [0.10–0.59], p=0.003) whereas lateral (OR=6.21 [2.47–15.52], p<0.001) or anterior (OR=5.79 [2.11–15.88], p=0.001) breach location were predictive of a high-grade breach.
Conclusion
iCT-Nav with post-instrumentation intraoperative imaging is associated with a reduced need for costly postoperative return to the operating room for screw revision. In comparison to studies of navigation without iCT where 1.5–1.7% of patients returned for a second surgery, we report 0 revision surgeries due to screw malpositioning.
... To the best of our knowledge, this is the first study to compare the entire neural arch's morphology along the entire lumbar spine in individuals afflicted with DS. This morphological data is very similar to other published data (normal and pathological) [30] from different populations and with varying sample sizes, thus strengthening our methods and conclusions (Table 6) [18,19,21,[30][31][32][33][34][35][36][37]. For example, in the mentioned studies, the pedicle width increases and the pedicle height decreases along the lumbar spine (L1-L5). ...
... To the best of our knowledge, this is the first study to compare the entire neural arch's morphology along the entire lumbar spine in individuals afflicted with DS. This morphological data is very similar to other published data (normal and pathological) [30] from different populations and with varying sample sizes, thus strengthening our methods and conclusions (Table 6) [18,19,21,[30][31][32][33][34][35][36][37]. For example, in the mentioned studies, the pedicle width increases and the pedicle height decreases along the lumbar spine (L1-L5). ...
Background
Although Degenerative Spondylolisthesis (DS) is a common osseous dysfunction, very few studies have examined the bony morphology of lumbar the neural arch in the population afflicted with DS. Therefore, this study aimed to characterize the neural arch (NA) morphology along the entire lumbar spine in individuals with degenerative spondylolisthesis (DS) and compare them to healthy controls.
Methods
One hundred CTs from a database of 500 lumbar CTs of spondylolisthesis were selected. We excluded vertebral fractures, non-L4-L5 slips, previous surgeries, vertebral spondyloarthropathies, and scoliosis. Scans were divided into a study group of 50 individuals with single-level DS (grades 1–2) at L4–5 (25 males and 25 females), and an age-sex matched control group of 50 individuals. Linear and angular measurements from all lumbar segments included: vertebral canals, intervertebral foramens, pedicles, and articular facets.
Results
Compared with the controls, all individuals with DS had greater pedicle dimensions in the lower lumbar segments (∆ = 1 mm–2.14 mm) and shorter intervertebral foramens in all the lumbar segments (∆range:1.85 mm–3.94 mm). In DS females, the lower lumbar facets were mostly wider (∆ = 1.73–2.86 mm) and more sagittally-oriented (∆10°) than the controls. Greater prevalence of grade-3 facet arthrosis was found only in the DS population (DS = 40–90%,controls = 16.7–66.7%). In DS males, degenerated facets were observed along the entire lumbar spine (L1-S1), whereas, in DS females, the facets were observed mainly in the lower lumbar segments (L4-S1) . Individuals with DS have shorter intervertebral foramens and greater pedicle dimensions compared with controls.
Conclusions
Females with DS have wider articular facets, more sagittally-oriented facets, and excessively degenerated facets than the controls. This unique NA shape may further clarify DS’s pathophysiology and explain its greater prevalence in females compared to males.
... accordance with the results of various other studies(4,7,9,11,13). However, few authors who were in disagreement with the current results included ChawlaK et al. (2011) who inferred that the mean pedicular width is equal on both sides (13) and Patil DK and Bhuiyan PS (2014) who concluded that mean pedicular width of lumbar vertebrae is more on left side as compared to the right side (8). ...
Background & Aims: With change of posture from quadrupeds to bipeds, a shift of body weight from appendicular skeleton to the axial skeleton (spine) occurs. As a result, various changes in the spine took place and the human spine became more prone to diseases such as scoliosis, spondylolisthesis, osteoporosis of vertebrae and many more. Over the past decade, a number of corrective surgeries have been designed but trans-pedicular screw fixation in spondylosyndesis remains the gold standard for the correcting spinal deformities. Hence, the current study was designed to frame out the morphometric measurements of the pedicle of lumbar vertebrae so that guidelines can be delineated for the manufacturers of lumbar screw implants.
Materials and Methods: The present cross-sectional descriptive study was conducted on 100 lumbar vertebrae of unknown age and sex obtained from the Department of Anatomy Govt. Medical College (GMC) Jammu. All the measurements were taken twice on both right and left side with the help of sliding vernier calipers, averaged out and then tabulated in Microsoft Excel spreadsheet.
Results: The dimensions of the pedicle height of the lumbar vertebrae on the right side were recorded to be from 20.05 to 10.32mm with mean of 13.83±2.08mm. However, mean of the pedicle height on left side was 13.71± 2.09mm with the range of 20.01 to 10.22mm with statistically significant p- value of 0.025. Further, the range of pedicular width of lumbar vertebrae on the right side was 17.71 to 5.38mm with a mean of 10.8±2.73mm and on left side was from 17.69 to 5.37 mm with mean of 9.77±2.57 mm with statistically significant p value of 0.037. The mean inter-pedicular distance of lumbar vertebrae was 21.73±2.62mm with a range of 11-28mm.
Conclusions: The results of the present study concluded that mean pedicular width and mean pedicular height are more on right side and mean inter- pedicular distance was 21.73±2.62mm. Hence, it was concluded that measurements should be taken before designing the lumbar screws for North Indian population.
