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The Occupancy of the Components in the Cervical Spine and Their Changes with Extension and Flexion.

ABSTRACT: Study Design Retrospective case series. Objectives The kinematics of the cervical spine has been investigated by many researchers. However, the occupancy of the disk bulges, spinal cord, ligamentum flavum, and the rest of the canal as well as the changes of these structures with motion have not yet been investigated. The goal of this study is to investigate these dynamic changes. Methods The kinetic magnetic resonance images of 248 patients (124 men and 124 women) were evaluated, and the occupancy of each structure for each cervical level at neutral, flexion, and extension were calculated. Results Whole canal anteroposterior (AP) diameters showed significant differences between neutral-extension and flexion-extension at the C4-C5 and C5-C6 levels (p < 0.05). The mean disk bulges showed significant differences between neutral-flexion and flexion-extension at the C4-C5, C5-C6, C6-C7, and C7-T1 levels (p < 0.01). The mean spinal canal AP diameter showed significant differences between flexion-extension and neutral-extension at the C3-C4, C4-C5, C5-C6, and C6-C7 levels (p < 0.05). There were significant differences between neutral-flexion at the C4-C5, C5-C6, and C6-C7 levels (p < 0.05). The mean thickness of the ligamentum flavum showed significant differences between flexion-extension at the C3-C4, C4-C5, C5-C6, and C6-C7 levels (p < 0.001). There were significant differences between neutral-extension at the C3-C4 and C5-C6 levels (p < 0.05). There were significant differences between neutral-flexion at the C5-C6 and C6-C7 levels (p < 0.05). The mean thickness of the spinal cord showed significant differences between neutral-flexion at the C2-C3 and C3-C4 levels (p < 0.05). There were significant differences between flexion-extension at the C3-C4 and C4-C5 levels (p < 0.01). The rest of the canal showed significant differences between neutral-extension and flexion-extension at the C3-C4, C4-C5, C5-C6, and C6-C7 levels (p < 0.005). There were significant differences between neutral-flexion at the C5-C6 and C6-C7 levels (p < 0.01). Conclusions The occupancy of each structure in the cervical spine for each level was revealed by this study. In addition, the dynamic changes in the cervical spine with flexion and extension were seen to have different characteristics for each level.

SUBMITTER: Sayıt E

PROVIDER: S-EPMC4577318 | biostudies-other | 2015 Oct

REPOSITORIES: biostudies-other

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Project description:A precise and comprehensive definition of "normal" in vivo cervical kinematics does not exist due to high intersubject variability and the absence of midrange kinematic data. In vitro test protocols and finite element models that are validated using only end range of motion data may not accurately reproduce continuous in vivo motion.The primary objective of this study was to precisely quantify cervical spine intervertebral kinematics during continuous, functional flexion-extension in asymptomatic subjects. The advantages of assessing continuous intervertebral kinematics were demonstrated by comparing asymptomatic controls with patients with single-level anterior arthrodesis.Cervical spine kinematics were determined during continuous in vivo flexion-extension in a clinically relevant age group of asymptomatic controls and a group of patients with C5-C6 arthrodesis.The patient sample consisted of 6 patients with single-level (C5-C6) anterior arthrodesis (average age: 48.8±6.9 years; 1 male, 5 female; 7.6±1.2 months postsurgery) and 18 asymptomatic control subjects of similar age (average age: 45.6±5.8 years; 5 male, 13 female).Outcome measures included the physiologic measure of continuous kinematic motion paths at each cervical motion segment (C2-C7) during flexion-extension.Participants performed flexion-extension while biplane radiographs were collected at 30 images per second. A previously validated tracking process determined three-dimensional vertebral positions with submillimeter accuracy. Continuous flexion-extension rotation and anterior-posterior translation motion paths were adjusted for disc height and static orientation of each corresponding motion segment.Intersubject variability in flexion-extension angle was decreased 15% to 46% and intersubject variability in anterior-posterior translation was reduced 14% to 33% after adjusting for disc height and static orientation angle. Average intersubject variability in continuous motion paths was 1.9° in flexion-extension and 0.6 mm in translation. Third-order polynomial equations were determined to precisely describe the continuous flexion-extension and anterior-posterior translation motion path at each motion segment (all R2>0.99).A significant portion of the intersubject variability in cervical kinematics can be explained by the disc height and the static orientation of each motion segment. Clinically relevant information may be gained by assessing intervertebral kinematics during continuous functional movement rather than at static, end range of motion positions. The fidelity of in vitro cervical spine mechanical testing protocols may be evaluated by comparing in vitro kinematics to the continuous motion paths presented.

Project description:BackgroundThe etiology of adjacent-segment disease following cervical spine arthrodesis remains controversial. The objective of the current study was to evaluate cervical intervertebral range of motion during dynamic flexion-extension in patients who had undergone a single-level arthrodesis and in asymptomatic control subjects.MethodsTen patients who had undergone a single-level (C5/C6) anterior arthrodesis and twenty asymptomatic control subjects performed continuous full range-of-motion flexion-extension while biplane radiographs were collected at thirty images per second. A previously validated tracking process determined three-dimensional vertebral position on each pair of radiographs with submillimeter accuracy. Six-degrees-of-freedom kinematics between adjacent vertebrae were calculated throughout the entire flexion-extension movement cycle over multiple trials for each participant. Cervical kinematics were also calculated from images collected during static full flexion and static full extension.ResultsThe C4/C5 motion segment moved through a larger extension range of motion and a smaller flexion range of motion in the subjects with the arthrodesis than in the controls. The extension difference between the arthrodesis and control groups was 3.8° (95% CI [confidence interval], 0.9° to 6.6°; p = 0.011) and the flexion difference was -2.9° (95% CI, -5.3° to -0.5°; p = 0.019). Adjacent-segment posterior translation was greater in the arthrodesis group than in the controls, with a C4/C5 difference of 0.8 mm (95% CI, 0.0 to 1.6 mm) and a C6/C7 difference of 0.4 mm (95% CI, 0.0 to 0.8 mm; p = 0.016). Translation range of motion and rotation range of motion were consistently larger when measured on images collected during dynamic functional movement as opposed to images collected at static full flexion or full extension. The upper 95% CI limit for anterior-posterior translation range of motion was 3.45 mm at C3/C4 and C4/C5, but only 2.3 mm at C6/C7.ConclusionsC5/C6 arthrodesis does not affect the total range of motion in adjacent vertebral segments, but it does alter the distribution of adjacent-segment motion toward more extension and less flexion superior to the arthrodesis and more posterior translation superior and inferior to the arthrodesis during in vivo functional loading. Range of motion measured from static full-flexion and full-extension images underestimates dynamic range of motion. Clinical evaluation of excessive anterior-posterior translation should take into account the cervical vertebral level.

Project description:BackgroundThe root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from a standing position and task specific spine ranges of motion objectively assess muscle function in healthy young and middle age individuals. However, literature on neuromuscular activation and associated spine and hip kinematics in older individuals is sparse. This cross sectional study sought to examine the sex and age (<40 versus >60 years) related differences in the neuromuscular activation profiles of the lumbar extensors and the related spine and hip kinematics from healthy individuals during a standardized trunk flexion-extension task.MethodsTwenty five older (13 females, 60-90 years) and 24 younger (12 females, 18-40 years) healthy individuals performed trunk flexion-extension testing by holding static positions at half-flexion way and full range of motion between standing and maximum trunk flexion. The associated lumbar extensor muscle activity was derived from measurements at standing, half, and maximum flexion positions. The range of motion at the hip and lumbar spine was recorded using 3d accelerometers attached to the skin overlying the multifidus and semispinalis thoracis muscles lateral to the L5 and T4 spinous processes, respectively. Statistical calculations were performed using a permutation ANOVA with bootstrap confidence intervals.ResultsThe muscle activity in the half related to the maximum flexion position (half flexion relaxation ratio) was significantly smaller in older males when compared with younger males. Moreover, measurements revealed smaller activity changes from standing to the half and from half to the maximum flexion position in older compared to younger individuals. Older males displayed smaller gross trunk range of motion from standing to maximum flexion than any other group.ConclusionsGender and normal aging significantly affect both the activation patterns of the lumbar extensor muscles and the kinematics of the trunk during a standardized trunk flexion-extension task. Measurement results from healthy young and middle age individuals should not be used for the assessment of individuals older than 60 years of age.

Project description:A longitudinal study using biplane radiography to measure in vivo intervertebral range of motion (ROM) during dynamic flexion/extension, and rotation.To longitudinally compare intervertebral maximal ROM and midrange motion in asymptomatic control subjects and single-level arthrodesis patients.In vitro studies consistently report that adjacent segment maximal ROM increases superior and inferior to cervical arthrodesis. Previous in vivo results have been conflicting, indicating that maximal ROM may or may not increase superior and/or inferior to the arthrodesis. There are no previous reports of midrange motion in arthrodesis patients and similar-aged controls.Eight single-level (C5/C6) anterior arthrodesis patients (tested 7?±?1 months and 28?±?6 months postsurgery) and six asymptomatic control subjects (tested twice, 58?±?6 months apart) performed dynamic full ROM flexion/extension and axial rotation whereas biplane radiographs were collected at 30?images per second. A previously validated tracking process determined three-dimensional vertebral position from each pair of radiographs with submillimeter accuracy. The intervertebral maximal ROM and midrange motion in flexion/extension, rotation, lateral bending, and anterior-posterior translation were compared between test dates and between groups.Adjacent segment maximal ROM did not increase over time during flexion/extension, or rotation movements. Adjacent segment maximal rotational ROM was not significantly greater in arthrodesis patients than in corresponding motion segments of similar-aged controls. C4/C5 adjacent segment rotation during the midrange of head motion and maximal anterior-posterior translation were significantly greater in arthrodesis patients than in the corresponding motion segment in controls on the second test date.C5/C6 arthrodesis appears to significantly affect midrange, but not end-range, adjacent segment motions. The effects of arthrodesis on adjacent segment motion may be best evaluated by longitudinal studies that compare maximal and midrange adjacent segment motion to corresponding motion segments of similar-aged controls to determine if the adjacent segment motion is truly excessive.3.

Project description:BackgroundThe analysis of sagittal intervertebral rotational motion (SIRM) can provide important information for the evaluation of cervical diseases. Deep learning has been widely used in spinal parameter measurements, however, there are few investigations on spinal motion analysis. The purpose of this study is to develop a deep learning-based model for fully automated measurement of SIRM based on flexion-neutral-extension cervical lateral radiographs and to evaluate its applicability for the flexion-extension (F/E), flexion-neutral (F/N), and neutral-extension (N/E) motion analysis.MethodsA total of 2796 flexion, neutral, and extension cervical lateral radiographs from 932 patients were analyzed. Radiographs from 100 patients were randomly selected as the test set, and those from the remaining 832 patients were used for training and validation. Landmarks were annotated for measuring SIRM at five segments from C2/3 to C6/7 on F/E, F/N, and N/E motion. High-Resolution Net (HRNet) was used as the main structure to train the landmark detection network. Landmark performance was assessed according to the percentage of correct key points (PCK) and mean of the percentage of correct key points (MPCK). Measurement performance was evaluated by intra-class correlation coefficient (ICC), Pearson correlation coefficient, mean absolute error (MAE), root mean square error (RMSE), and Bland-Altman plots.ResultsAt a 2-mm distance threshold, the PCK for the model ranged from 94 to 100%. Compared with the reference standards, the model showed high accuracy for SIRM measurements for all segments on F/E and F/N motion. On N/E motion, the model provided reliable measurements from C3/4 to C6/7, but not C2/3. Compared with the radiologists' measurements, the model showed similar performance to the radiologists.ConclusionsThe developed model can automatically measure SIRM on flexion-neutral-extension cervical lateral radiographs and showed comparable performance with radiologists. It may provide rapid, accurate, and comprehensive information for cervical motion analysis.

Project description:BackgroundThe quality of flexion-extension motion after cervical disc arthroplasty has been a subject of interest due to the number of available devices with different designs and kinematics. Previous studies of motion quality have been limited to measuring the range of motion using two radiographs taken at the extremes of flexion and extension. This is the first study evaluating the in vivo quality of index segment motion using fluoroscopic images collected over the arc of flexion-extension after M6-C cervical disc arthroplasty surgery.MethodsEligible participants had previously undergone a single-level cervical disc arthroplasty surgery for degenerative cervical spine disease performed by the senior author. Study participants underwent dynamic lateral fluoroscopic imaging to capture the C2-C7 motion between maximal flexion and extension. The amount of motion contribution by individual segments to the C2-C7 motion (termed segmental motion fraction) and its variation throughout the arc of flexion-extension were compared between the index and adjacent segments. The shift of centre of rotation during the arc of motion was also assessed.ResultsTen subjects with a mean age of 43.8 years old were recruited, with an average follow-up of 16.2 months at the time of fluoroscopy. The C2-C7 cervical spine had an average flexion-extension range of 66.7 degrees. The contribution of the index segment averaged over the flexion-extension arc of motion was 18.9% (peak contribution 24.4%) for the C5-C6 group; and 15.5% (peak contribution 25.5%) for the C6-C7 group. The mean cranial-caudal location of the centre of rotation progressively shifted in the cranial direction from C2-C3 to C6-C7 motion segment.ConclusionsOur results demonstrated physiologic quality of motion at the index segment and harmony among its neighbouring segments following cervical disc arthroplasty, without gearshift-like intermittent locking of the prosthesis during the arc of flexion-extension motion. This pilot study provides a basis for the design of future long-term studies with larger sample size to compare the quality of motion between different cervical disc prostheses using the concept of segmental motion fraction as a motion-quality metric.

Project description:BackgroundMeasurement of lumbar spine range of motion (ROM) is often considered to be an essential component of lumbar spine physiotherapy and orthopedic assessment. The measurement can be carried out through various instruments such as inclinometers, goniometers, and etc. Recent smartphones have been equipped with accelerometers and magnetometers, which, through specific software applications (apps) can be used for inclinometric functions.PurposeThe main purpose was to investigate the reliability and validity of an iPhone(®) app (TiltMeter(©) -advanced level and inclinometer) for measuring standing lumbar spine flexion-extension ROM in asymptomatic subjects.DesignA cross-sectional study was carried out.SettingThis study was conducted in a physiotherapy clinic located at School of Rehabilitation Sciences, Iran University of Medical Science and Health Services, Tehran, Iran.SubjectsA convenience sample of 30 asymptomatic adults (15 males; 15 females; age range = 18-55 years) was recruited between August 2015 and December 2015.MethodsFollowing a 2-minute warm-up, the subjects were asked to stand in a relaxed position and their skin was marked at the T12-L1 and S1-S2 spinal levels. From this position, they were asked to perform maximum lumbar flexion followed by maximum lumbar extension with their knees straight. Two blinded raters each used an inclinometer and the iPhone (®) app to measure lumbar spine flexion-extension ROM. A third rater read the measured angles. To calculate total lumbar spine flexion-extension ROM, the measurement from S1-S2 was subtracted from T12-L1. The second (2 hours later) and third (48 hours later) sessions were carried out in the same manner as the first session. All of the measurements were conducted 3 times and the mean value of 3 repetitions for each measurement was used for analysis. Intraclass correlation coefficient (ICC) models (3, k) and (2, k) were used to determine the intra-rater and inter-rater reliability, respectively. The Pearson correlation coefficients were used to establish concurrent validity of the iPhone(®) app. Furthermore, minimum detectable change at the 95% confidence level (MDC95) was computed as 1.96 × standard error of measurement × [Formula: see text].ResultsGood to excellent intra-rater and inter-rater reliability were demonstrated for both the gravity-based inclinometer with ICC values of ?0.84 and ?0.77 and the iPhone(®) app with ICC values of ?0.85 and ?0.85, respectively. The MDC95 ranged from 5.82°to 8.18°for the intra-rater analysis and from 7.38°to 8.66° for the inter-rater analysis. The concurrent validity for flexion and extension between the 2 instruments was 0.85 and 0.91, respectively.ConclusionsThe iPhone(®)app possesses good to excellent intra-rater and inter-rater reliability and concurrent validity. It seems that the iPhone(®) app can be used for the measurement of lumbar spine flexion-extension ROM.Level of evidenceIIb.

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The Occupancy of the Components in the Cervical Spine and Their Changes with Extension and Flexion.

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