Middle Cervical Spine Research Articles

Functional division and age differences in cervical spine of males and females

Introduction. The cervical spine from osteopathy point of view, taking into account spine functional division, includes vertebrae of the cervical-thoracic junction, and the approach requires additional coordination. The X-ray examination experience with the entire spine integrity suggests that both cervical vertebrae and vertebrae of cervical-thoracic junction are the place of the greatest age-related changes. The study of gender difference in cervical spine vertebra positions and its age-related dynamics requires additional attention. The purpose of the work: on the basis of digital radiographs to develop an integral indicator for assessing the position of the vertebrae of the middle cervical spine; research objectives: to quantify vertebra positions from CIII–VI; to propose a characteristic of transition smoothness from vertebral CIII–VI group to the vertebral CVII–TIII group; to study the male/female features of age trend in cervical spine shape.Materials and methods. Radiographs of all spine parts in sagittal plane were examined for 141 patients with dorsopathies (57 males and 84 females). The cohort of patients is divided into 4 groups: I (n=31) — 21–44 years (average age 33,1 years); II (n=39) — 45–59 years (average age 52,6 years); III (n=50) — 60–74 years (average age 66,8 years); IV (n=21) — 75–88 years (average age 81,1 years). A single digital X-ray spine image in sagittal plane was obtained for each patient. On the combined digital radiograph, the occipital vertical was drawn along all spine parts, starting from the external tubercle of occipital bone, and anteroposterior axes for CIII–TIII vertebrae (r axes) were drawn. The angles between the occipital vertical and the perpendiculars restored to the axes at the points of their intersection with the occipital vertical were measured. Statistical processing of the data obtained was carried out.Results. The St integral indicator has been developed to quantify the vertebra position of middle cervical spine. It was calculated by formula St = (rCIII+rCIV+rCV +rCVI)/4. Using St the type boundaries are determined, and four displacement types for the cervical vertebra group (from CIII–VI) are identifi ed: I — low start; II — medium start; III — high start; IV — ultra-high start. An age-related trend of changes in CIII–VI vertebra position was detected. The correlation between the position indicator St of the middle cervical vertebrae and indicator ArCT for the vertebrae of cervical-thoracic junction CVII–TIII was proved. Gender differences depending on age were revealed in transition smoothness between these spine parts.Conclusion. Some arguments have been obtained confi rming the validity of attributing the vertebra group of cervical-thoracic junction from CVII to TIII to the functional unity of cervical spine. Quantitative smoothness assessment of transition from the middle cervical spine to the vertebra group of cervical-thoracic junction can be carried out by calculating the difference between the ArCT and St indicators. The difference demonstrates age-related shape features of the spine part for males and females.

Posture and Helmet Configuration Effects on Joint Reaction Loads in the Middle Cervical Spine.

INTRODUCTION: Between 43 and 97% of helicopter pilots in the Canadian Armed Forces report neck pain. Potential contributing factors include the weight of their helmet, night vision goggles (NVG), and counterweight (CW) combined with deviated neck postures. Therefore, the purpose of this investigation was to quantify changes in neck loads associated with posture, helmet, NVG, and CW.METHODS: Eight male subjects volunteered. They undertook one of five deviated neck postures (flexion, extension, lateral bending, axial rotation) times four configurations (no helmet, helmet only, helmet and NVG, and helmet, NVG, and CW). 3D kinematics and EMG from 10 muscles (5 bilaterally) drove a 3D inverse dynamics, EMG-driven model of the cervical spine which calculated joint compression and shear at C5-C6.RESULTS: The compression in the neutral posture was 116.5 (5.7) N, which increased to 143.7 (11.4) N due to a 12.7 N helmet. NVGs, weighing 7.9 N, also generated this disproportionate increase, where the compression was 164.2 (3.7) N. In flexion or extension, the compression increased with increasing head-supported mass, with a maximum of 315.8 (67.5) N with the CW in flexion. Anteroposterior shear was highest in the lateral bending [34.0 (6.2) N] condition, but was generally low (< 30 N). Mediolateral shear was less than 5 N for all conditions.DISCUSSION: Repositioning the center of gravity of the helmet with either NVGs or CW resulted in posture-specific changes to loading. Posture demonstrated a greater potential to reposition the head segment's center of gravity compared to the helmet design. Therefore, helmet designs which consider repositioning the center of gravity may reduce loads in one posture, but likely exacerbate loading in other postures.Barrett JM, McKinnon CD, Dickerson CR, Laing AC, Callaghan JP. Posture and helmet configuration effects on joint reaction loads in the middle cervical spine. Aerosp Med Hum Perform. 2022; 93(5):458-466.

Accuracy of pedicle screw placement using patient-specific template guide system

BackgroundDespite repeated efforts for accurate cervical pedicle screw insertion, malpositioning of the inserted screw is commonly noted. To avoid neurovascular complications during cervical pedicle screw insertion, we have developed a new patient-specific screw guide system. This study aimed to evaluate the accuracy of cervical PS placement using the new patient-specific screw guide system. MethodsThis study is a retrospective clinical evaluation of prospectively enrolled patients. Seventeen consecutively enrolled patients who underwent posterior cervical fusion using the guide system were included. Firstly, three-dimensional planning of pedicle screw placement was done using simulation software. A screw guide for each vertebra was constructed preoperatively. A total of 77 screws were inserted with the guides. Postoperative computed tomography was used to evaluate pedicle perforation, and screw deviations, between the planned and actual screw positions, were measured. ResultsA total of 76 screws (98.7%) were completely inside the pedicle (C3-7), without neurovascular injuries. The mean screw deviations from the planned trajectory at the narrowest point of the pedicle and at the entry point in the axial and sagittal planes were 0.56 ± 0.43 mm and 0.43 ± 0.35 mm and 0.43 ± 0.30 mm and 0.63 ± 0.50 mm, respectively. There were no significant differences in any parameter at different spinal levels. Angular deviations in the sagittal and axial planes were 2.94 ± 2.04° and 2.53 ± 1.85°, respectively. Sagittal angular deviations tended to increase in the cranial vertebra (C3 and C4) compared to the middle cervical spine. ConclusionsWe demonstrated that our patient-specific screw guide is vital for guiding precise screw insertion in the cervical pedicle. This technique may be an effective solution for achieving precise screw insertion and reducing the incidence of complications.

Minor Structural Differences in the Cervical Spine Between Patients With Cervical Dystonia and Age-Matched Healthy Controls.

Background: Cervical dystonia is the most common form of focal dystonia. The frequency and pattern of degenerative changes of the cervical spine in patients with cervical dystonia and their relation to clinical symptoms remain unclear as no direct comparison to healthy controls has been performed yet. Here, we used magnetic resonance imaging (MRI) to investigate (1) whether structural abnormalities of the cervical spine are more common in patients with cervical dystonia compared to age-matched healthy controls, (2) if there are clinical predictors for abnormalities on MRI, and (3) to calculate the inter-rater reliability of the respective radiological scales.Methods: Twenty-five consecutive patients with cervical dystonia and 20 age-matched healthy controls were included in the study. MRI scans of the cervical spine were analyzed separately by three experienced raters blinded to clinical information, applying different MRI rating scales. Structural abnormalities were compared between groups for upper, middle, and lower cervical spine segments. The associations between scores differentiating both groups and clinical parameters were assessed in dystonia patients. Additionally, inter-rater reliability of the MRI scales was calculated.Results: Comparing structural abnormalities, we found minor differences in the middle cervical spine, indicated by a higher MRI total score in patients but no significant correlation between clinical parameters and MRI changes. Inter-rater reliability was satisfying for most of the MRI rating scales.Conclusion: Our results do not provide evidence for a role of MRI of the cervical spine in the routine work-up of patients with cervical dystonia in the absence of specific clinical signs or symptoms.

Recurrent neck pain patients exhibit altered joint motion pattern during cervical flexion and extension movements

BackgroundImpaired sensorimotor ability has been demonstrated in recurrent neck pain patients. It is however not clear if cervical joint motion and pressure pain sensitivity in recurrent neck pain patients are different from asymptomatic controls. MethodsCervical flexion and extension motions were examined by video-fluoroscopy and pressure pain thresholds were assessed bilaterally over C2/C3, C5/C6 facet joints and right tibialis anterior in eighteen recurrent neck pain patients and eighteen healthy subjects. Individual joint motion was analyzed by dividing fluoroscopic videos into 10 epochs. The motion opposite to the primary direction (anti-directional motion) and motion along with the primary direction (pro-directional motion) of each joint were extracted across epochs. Total joint motion was the sum of anti-directional and pro-directional motions. Joint motion variability was represented by the variance of joint motions across epochs. FindingsCompared to controls, recurrent neck pain patients showed: 1) decreased anti-directional motion at C2/C3 and C3/C4 (P < 0.05) and increased anti-directional motion at C5/C6 and C6/C7 (P < 0.05) during extension motion. 2) Increased overall anti-direction motion during flexion motion (P < 0.05). 3) Lower joint motion variability at C3/C4 during extension motion (P < 0.05). InterpretationRecurrent neck pain patients showed a redistribution of anti-directional motion between the middle cervical spine and the lower cervical spine during cervical extension and increased overall anti-directional motion during cervical flexion compared with healthy controls. The anti-directional motion was more sensitive to neck pain compared to other cervical joint motion parameters in the present study.

Patterns of Cervical Disc Degeneration: Analysis of Magnetic Resonance Imaging of Over 1000 Symptomatic Subjects.

Study Design:Cross-sectional study.Objectives:The aim of this study was to evaluate cervical disc degeneration on magnetic resonance imaging (MRI) in a large population of symptomatic patients and to provide baseline data on the pattern of degeneration in order to understand how the cervical spine ages.Methods:We performed a cross-sectional study of 1059 patients who underwent upright cervical MRI for neck pain with and without neurological symptoms. A total of 6354 cervical discs from C2/3 to C7/T1 were evaluated. Cervical disc degeneration was evaluated on T2-weighted MRI and graded into 4 categories (Grades 0-III). Positive degeneration was defined as greater than Grade II. The correlation between age and total grade of degeneration of each patient was evaluated, as well as the prevalence and pattern of degeneration.Results:The average number of degenerated disc levels and the total grade of cervical disc degeneration significantly increase with age. In the patient group with 1-level degeneration, C5/6 was the most common degenerated level followed by C4/5 and C6/7. In the group with 2-level degeneration, C5/6 & C6/7 was most common followed by C4/5 & C5/6 and C3/4 & C4/5. Skip level degeneration was significantly rarer than contiguous level degeneration, and C7/T1 and C2/3 were the most unlikely to degenerate in multilevel degeneration.Conclusion:Disc degeneration is most common in the middle cervical spine (C5/6) and progresses to contiguous levels, except for C7/T1 and C2/3. This pattern may play a role in adjacent-level disc degeneration associated with spinal fusion.

Screw perforation rates in 359 consecutive patients receiving computer-guided pedicle screw insertion along the cervical to lumbar spine.

Pedicle screw (PS) insertion has been criticized for its risk of serious injury to neurovascular structures. Although computed tomography (CT)-based navigation has been developed to avoid such complications, perforation remains an issue, even with the aid of additional guidance. We clarify screw perforation rate and direction in 359 consecutive patients treated using CT-based PS insertion and present important considerations for more accurate screw placement. The medical records of 359 consecutive patients who underwent PS insertion involving C2-L5 using a CT-based navigation system were reviewed. Postoperative CT images were analyzed to evaluate the accuracy of screw placement. We investigated both rate and direction of screw perforation according to vertebral level. Of the 3413 PS that were inserted, 6.9% were judged as Grade 2 or 3 perforations. The combined rate of these perforations was 5.0% for C2, 11.4% for C3-5, 7.0% for C6-7, 10.4% for T1-4, 8.8% for T5-8, 4.5% for T9-12, and 3.8% for L1-5. We also analyzed the odds ratio (OR) for screw perforation in vertebrae accounting for the effects of age and disease. Multivariate analysis identified that PS insertions at C3-5 (OR 2.9, 95% CI 1.6-5.1; p<0.001), T1-4 (OR 2.7, 95% CI 1.6-4.7; p<0.001), and T5-8 (OR 2.3; 95% CI 1.4-3.8; p=0.001) were significantly associated with Grade 2 or 3 screw perforation as compared with that of L1-5. Even with CT-based navigation, careful insertion of PS is needed in the middle cervical spine because of a significantly higher perforation rate as compared with the lumbar region.

The shift of segmental contribution ratio in patients with herniated disc during cervical lateral bending.

BackgroundAbnormal intervertebral movements of spine have been reported to be associated with trauma and pathological conditions. The importance of objective spinal motion imaging assessment in the frontal plane was frequently underestimated. The clinical evaluation of the segmental motion contribution could be useful for detecting the motion pattern of individual vertebrae. Therefore the purpose of this study was to investigate the shift of segmental contribution ratio in patients with herniated disc during cervical lateral bending to provide additional insights to cervical biomechanics.MethodsA total of 92 subjects (46 healthy adult subjects and 46 disc-herniated patients) were enrolled in this case–control study. The motion images during cervical lateral bending movements were digitized using a precise image protocol to analyze the intervertebral motion and contribution.ResultsOur results showed that the intervertebral angulation during cervical lateral bending for the C2/3 to C6/7 segments were 7.66°±2.37°, 8.37°±2.11°, 8.91°±3.22°, 7.19°±2.29°, 6.31°±2.11°, respectively for the healthy subjects. For the patients with herniated disc, the intervertebral angulation for the C2/3 to C6/7 segments were 6.87°±1.67°, 7.83°±1.79°, 7.73°±2.71°, 5.13°±2.05°, 4.80°±1.93°, respectively. There were significant angulation and translational differences between healthy subjects and the patients with herniated disc in the C5/6 and C6/7 segments (P=0.001-0.029). The segmental contributions of the individual vertebral segments were further analyzed. There was a significant increase in segmental contribution ratio of C3/4 (P=0.048), while a significant decrease in contribution ratio of C5/6 (P=0.037) was observed in the patients with herniated disc. Our results indicated that the segmental contribution shifted toward the middle cervical spine in the patients with herniated disc.ConclusionsThe segmental contributions of cervical spine during lateral bending movement were first described based on the validated radiographic protocol. The detection of the shift of segmental contribution ratio could be helpful for the diagnosis the motion abnormality resulted from the disc or, facet pathologies, and arthritic changes of cervical spine.

Instabilité du rachis cervical par traumatisme en compression axiale : une étude biomécanique

BackgroundAxial compression injuries of the cervical spine occur during contact sports, automobile collisions, and falls. The objective of this study was to use flexibility tests to determine biomechanical instability of the cervical spine due to simulated axial compression injuries. HypothesisWe hypothesized that the axial compression injuries cause severe biomechanical instability throughout the cervical spine. Materials and methodsThe injuries were simulated using 2.4m/s head-first impacts of a cadaveric cervical spine model (n=10) mounted horizontally to a torso-equivalent mass on a sled and carrying a surrogate head in protruded posture. Intact and post-impact flexibility tests were performed up to 1.5, 3, and 1.5 Nm in flexion-extension, axial torque, and lateral bending, respectively. Instability parameters of range of motion (RoM) and neutral zone (NZ) were determined for injured spinal levels and statistically compared (P<0.05) between intact and post-impact. ResultsThe sagittal instability parameters indicated extension-compression injuries at the upper and middle cervical spine and flexion-compression injuries at the lower cervical spine. Increases in extension RoM were 14.9° at the upper cervical spine and 24.9° (P<0.05) at the middle cervical spine and in flexion RoM at C7/T1 were 25.6°. RoM and NZ increases in axial rotation and lateral bending were nearly symmetric among left and right. DiscussionMultidirectional instability of the upper cervical spine caused by atlas and dens fractures was evidenced by increases between 36% and 53% in RoM and NZ due to the impacts. The sagittal RoM of injured spinal levels of the middle and lower cervical spine exceeded a proposed threshold for clinical instability by between 67% and 114%. The instability documented throughout the cervical spine was consistent with clinical observations of cord injuries and paralysis in patients. Level of evidenceLevel IV, controlled laboratory investigation.

Cervical spine instability following axial compression injury: A biomechanical study

BackgroundAxial compression injuries of the cervical spine occur during contact sports, automobile collisions, and falls. The objective of this study was to use flexibility tests to determine biomechanical instability of the cervical spine due to simulated axial compression injuries. HypothesisWe hypothesized that the axial compression injuries cause severe biomechanical instability throughout the cervical spine. Materials and methodsThe injuries were simulated using 2.4m/s head-first impacts of a cadaveric cervical spine model (n=10) mounted horizontally to a torso-equivalent mass on a sled and carrying a surrogate head in protruded posture. Intact and post-impact flexibility tests were performed up to 1.5, 3, and 1.5Nm in flexion-extension, axial torque, and lateral bending, respectively. Instability parameters of range of motion (RoM) and neutral zone (NZ) were determined for injured spinal levels and statistically compared (P<0.05) between intact and post-impact. ResultsThe sagittal instability parameters indicated extension-compression injuries at the upper and middle cervical spine and flexion-compression injuries at the lower cervical spine. Increases in extension RoM were 14.9° at the upper cervical spine and 24.9° (P<0.05) at the middle cervical spine and in flexion RoM at C7/T1 were 25.6°. RoM and NZ increases in axial rotation and lateral bending were nearly symmetric among left and right. DiscussionMultidirectional instability of the upper cervical spine caused by atlas and dens fractures was evidenced by increases between 36% and 53% in RoM and NZ due to the impacts. The sagittal RoM of injured spinal levels of the middle and lower cervical spine exceeded a proposed threshold for clinical instability by between 67% and 114%. The instability documented throughout the cervical spine was consistent with clinical observations of cord injuries and paralysis in patients. Level of evidenceLevel IV, controlled laboratory investigation.

Do Cervical Collars and Cervicothoracic Orthoses Effectively Stabilize the Injured Cervical Spine? A Biomechanical Investigation

In vitro biomechanical study. Our objective was to determine the effectiveness of cervical collars and cervicothoracic orthoses for stabilizing clinically relevant, experimentally produced cervical spine injuries. Most previous in vitro studies of cervical orthoses used a simplified injury model with all ligaments transected at a single spinal level, which differs from real-life neck injuries. Human volunteer studies are limited to measuring only sagittal motions or 3-dimensional motions only of the head or 1 or 2 spinal levels. Three-plane flexibility tests were performed to evaluate 2 cervical collars (Vista Collar and Vista Multipost Collar) and 2 cervicothoracic orthoses (Vista TS and Vista TS4) using a skull-neck-thorax model with 8 injured cervical spine specimens (manufacturer of orthoses: Aspen Medical Products Inc, Irvine, CA). The injuries consisted of flexion-compression at the lower cervical spine and extension-compression at superior spinal levels. Pair-wise repeated measures analysis of variance (P < 0.05) and Bonferroni post hoc tests determined significant differences in average range of motions of the head relative to the base, C7 or T1, among experimental conditions. RESULTS.: All orthoses significantly reduced unrestricted head/base flexion and extension. The orthoses allowed between 8.4% and 25.8% of unrestricted head/base motion in flexion/extension, 57.8% to 75.5% in axial rotation, and 53.8% to 73.7% in lateral bending. The average percentages of unrestricted motion allowed by the Vista Collar, Vista Multipost Collar, Vista TS, and Vista TS4 were: 14.0, 9.7, 6.1, and 4.7, respectively, for middle cervical spine extension and 13.2, 11.8, 3.3, and 0.4, respectively, for lower cervical spine flexion. Successive increases in immobilization were observed from Vista Collar to Vista Multipost Collar, Vista TS, and Vista TS4 in extension at the injured middle cervical spine and in flexion at the injured lower cervical spine. Our results may assist clinicians in selecting the most appropriate orthosis based upon patient-specific cervical spine injuries.

Head-First Impact With Head Protrusion Causes Noncontiguous Injuries of the Cadaveric Cervical Spine

To simulate horizontally aligned head-first impacts with initial head protrusion using a human cadaveric neck model and to determine biomechanical responses, injuries, and injury severity. Head-first impacts with initial head protrusion were simulated at 2.4 m/s using a human cadaver neck model (n = 10) mounted horizontally to a torso-equivalent mass on a sled and carrying a surrogate head. Macroscopic neck injuries were determined, and ligamentous injuries were quantified using fluoroscopy and visual inspection after the impacts. Representative time-history responses for injured specimens were determined during impact using load cell data and analyses of high-speed video. Biomechanics research laboratory. Cervical spines of 10 human cadavers. Injury severity at the middle and lower cervical spine was statistically compared using a 2-sample t test (P < 0.05). Neck buckling consisted of hyperflexion at C6/7 and C7/T1 and hyperextension at superior spinal levels. Noncontiguous neck injuries included forward dislocation at C7/T1, spinous process fracture and compression-extension injuries at the middle cervical spine, and atlas and odontoid fractures. Ligamentous injury severity at C7/T1 was significantly greater than at the middle cervical spine. Distinct injury mechanisms were observed throughout the neck, consisting of extension-compression and posterior shear at the upper and middle cervical spine and flexion-compression and anterior shear at C6/7 and C7/T1. Our experimental results highlight the importance of clinical awareness of potential noncontiguous cervical spine injuries due to head-first sports impacts.

Three-dimensional motion of the uncovertebral joint during head rotation

The uncovertebral joints are peculiar but clinically important anatomical structures of the cervical vertebrae. In the aged or degenerative cervical spine, osteophytes arising from an uncovertebral joint can cause cervical radiculopathy, often necessitating decompression surgery. Although these joints are believed to bear some relationship to head rotation, how the uncovertebral joints work during head rotation remains unclear. The purpose of this study is to elucidate 3D motion of the uncovertebral joints during head rotation. Study participants were 10 healthy volunteers who underwent 3D MRI of the cervical spine in 11 positions during head rotation: neutral (0°) and 15° increments to maximal head rotation on each side (left and right). Relative motions of the cervical spine were calculated by automatically superimposing a segmented 3D MR image of the vertebra in the neutral position over images of each position using the volume registration method. The 3D intervertebral motions of all 10 volunteers were standardized, and the 3D motion of uncovertebral joints was visualized on animations using data for the standardized motion. Inferred contact areas of uncovertebral joints were also calculated using a proximity mapping technique. The 3D animation of uncovertebral joints during head rotation showed that the joints alternate between contact and separation. Inferred contact areas of uncovertebral joints were situated directly lateral at the middle cervical spine and dorsolateral at the lower cervical spine. With increasing angle of rotation, inferred contact areas increased in the middle cervical spine, whereas areas in the lower cervical spine slightly decreased. In this study, the 3D motions of uncovertebral joints during head rotation were depicted precisely for the first time.

Neck injury response to direct head impact

Previous in vivo studies have observed flexion of the upper or upper/middle cervical spine and extension at inferior spinal levels due to direct head impacts. These studies hypothesized that hyperflexion may contribute to injury of the upper or middle cervical spine during real-life head impact. Our objectives were to determine the cervical spine injury response to direct head impact, document injuries, and compare our results with previously reported in vivo data. Our model consisted of a human cadaver neck (n=6) mounted to the torso of a rear impact dummy and carrying a surrogate head. Rearward force was applied to the model's forehead using a cable and pulley system and free-falling mass of 3.6kg followed by 16.7kg. High-speed digital cameras tracked head, vertebral, and pelvic motions. Average peak spinal rotations observed during impact were statistically compared (P<0.05) to physiological ranges obtained from intact flexibility tests. Peak head impact force was 249 and 504N for the 3.6 and 16.7kg free-falling masses, respectively. Occipital condyle loads reached 205.3N posterior shear, 331.4N compression, and 7.4Nm extension moment. We observed significant increases in intervertebral extension peaks above physiologic at C6/7 (26.3° vs. 5.7°) and C7/T1 (29.7° vs. 4.6°) and macroscopic ligamentous and osseous injuries at C6 through T1 due to the 504N impacts. Our results indicate that a rearward head shear force causes complex neck loads of posterior shear, compression, and extension moment sufficient to injure the lower cervical spine. Real-life neck injuries due to motor vehicle crashes, sports impacts, or falls are likely due to combined loads transferred to the neck by direct head impact and torso inertial loads.

Development of a Clinical Prediction Rule to Identify Patients With Neck Pain Likely to Benefit From Thrust Joint Manipulation to the Cervical Spine

Prospective cohort/predictive validity study. To determine the predictive validity of selected clinical examination items and to develop a clinical prediction rule to determine which patients with neck pain may benefit from cervical thrust joint manipulation (TJM) and exercise. TJM to the cervical spine has been shown to be effective in patients presenting with a primary report of neck pain. It would be useful for clinicians to have a decision-making tool, such as a clinical prediction rule, that could accurately identify which subgroup of patients would respond positively to cervical TJM. Consecutive patients who presented to physical therapy with a primary complaint of neck pain completed a series of self-report measures, then received a detailed standardized history and physical examination. After the clinical examination, all patients received a standardized treatment regimen consisting of cervical TJM and range-of-motion exercise. Depending on response to treatment, patients were treated for 1 or 2 sessions over approximately 1 week. At the end of their participation in the study, patients were classified as having experienced a successful outcome based on a score of +5 ("quite a bit better") or higher on the global rating of change scale. Sensitivity, specificity, and positive and negative likelihood ratios were calculated for all potential predictor variables. Univariate techniques and stepwise logistic regression were used to determine the most parsimonious set of variables for prediction of treatment success. Variables retained in the regression model were used to develop a multivariate clinical prediction rule. Eighty-two patients were included in data analysis, of whom 32 (39%) achieved a successful outcome. A clinical prediction rule with 4 attributes (symptom duration less than 38 days, positive expectation that manipulation will help, side-to-side difference in cervical rotation range of motion of 10° or greater, and pain with posteroanterior spring testing of the middle cervical spine) was identified. If 3 or more of the 4 attributes (positive likelihood ratio of 13.5) were present, the probability of experiencing a successful outcome improved from 39% to 90%. The clinical prediction rule may improve decision making by providing the ability to a priori identify patients with neck pain who are likely to benefit from cervical TJM and range-of-motion exercise. However, this is only the first step in the process of developing and testing a clinical prediction rule, as future studies are necessary to validate the results and should include long-term follow-up and a comparison group. Prognosis, level 2b.

Prognostic Value of 18F-FDG PET in Monosegmental Stenosis and Myelopathy of the Cervical Spinal Cord

MRI offers perfect visualization of spondylotic stenosis of the cervical spine, but morphologic imaging does not correlate with clinical symptoms and postoperative recovery after decompression surgery. In this prospective study, we investigated the role of (18)F-FDG PET in patients with degenerative stenosis of the cervical spinal cord in relation to postsurgical outcome. Twenty patients with monosegmental spondylotic stenosis of the middle cervical spine (C3/C4 or C4/C5) showing intramedullary hyperintensity on T2-weighted MRI and clinical symptoms of myelopathy (myelopathic patients) were investigated by (18)F-FDG PET. Maximum standardized uptake values (SUV(max)) were measured at all levels of the cervical spine (C1-C7). Decompression surgery and anterior cervical fusion were performed on all patients, and clinical status (Japanese Orthopedic Association [JOA] score) was assessed before and 6 mo after surgery. The (18)F-FDG data of 10 individuals without cervical spine pathology were used as a reference (controls). The myelopathic patients showed a significant decrease in (18)F-FDG uptake in the area of the lower cervical cord, compared with the control group (C7 SUV(max), 1.49 ± 0.18 vs. 1.71 ± 0.27, P = 0.01). Ten myelopathic patients exhibited focally increased (18)F-FDG uptake at the level of the stenosis (SUV(max), 2.27 ± 0.41 vs. 1.75 ± 0.22, P = 0.002). The remaining 10 patients showed inconspicuous (18)F-FDG uptake at the area of the stenosis. Postoperatively, the patients with focally increased (18)F-FDG accumulation at the level of stenosis showed good clinical recovery and a significant improvement in JOA scores (13.6 ± 2.3 vs. 9.5 ± 2.5, P = 0.001), whereas no significant improvement was observed in the remaining patients (JOA score, 12.0 ± 2.4 vs. 11.6 ± 2.5, not statistically significant). Multiple regression analysis identified the presence of focally increased (18)F-FDG uptake at the level of the stenosis as an independent predictor of postoperative outcome (P = 0.002). The results suggest that regional changes in (18)F-FDG uptake have prognostic significance in compression-induced cervical myelopathy that may be helpful in decisions on the timing of surgery.

In Vivo Three-Dimensional Kinematics of the Cervical Spine During Head Rotation in Patients With Cervical Spondylosis

Kinematics of the cervical spine during head rotation was investigated using 3-dimensional (3D) magnetic resonance imaging (MRI) in patients with cervical spondylosis (CS). To demonstrate in vivo 3D kinematics of the spondylotic cervical spine during head rotation. Several in vivo studies have identified kinematic differences between normal and spondylotic subjects, but only two-dimensional flexion/extension motion has been investigated. Differences of in vivo 3D cervical motion during head rotation between normal and spondylotic subjects have yet to be clarified. Ten healthy volunteers (control group) and 15 patients with CS (CS group) underwent 3D MRI of the cervical spine with the head rotated to 5 positions (neutral, ±45° and ±maximal head rotation). Relative motions of the cervical spine were calculated by automatically superimposing a segmented 3D MRI of the vertebra in the neutral position over images for each position using volume registration. The 3D motions of adjacent vertebra were represented with 6 degrees of freedom by Euler angles and translations on the coordinate system. Compared with the control group, the CS group showed significantly decreased mean axial rotation and mean coupled lateral bending at C5-C6 and C6-C7 and significantly increased mean coupled lateral bending at C2-C3 and C3-C4, although both the groups showed the same pattern of coupled motions. The in vivo 3D kinematics of the spondylotic cervical spine during head rotation was accurately depicted and compared with those of healthy cervical spines for the first time.

Vertebral rotation during pedicle screw insertion in patients with cervical injury

Cervical pedicle screws, when misplaced, tend to perforate laterally. One of the reasons for lateral perforation is vertebral rotation during screw insertion. However, actual vertebral rotation during pedicle screw insertion is unknown. In this study, we measured vertebral rotation during pedicle screw insertion in patients with cervical injury. We inserted 76 pedicle screws into 38 vertebrae (C2 to C7) in 17 patients. All patients had some type of cervical injury. Screws were placed using intraoperative acquisition of data acquired with the isocentric C-arm fluoroscope (Iso-C3D) and computer navigation. We made screw holes using an image-guided awl, and we took images of cervical vertebrae in the neutral and rotational positions using navigation. Images of 76 insertions and rotational positions were taken while each cervical vertebra was under maximum stress at the time we were making the pedicle hole by awl. Average cervical vertebra rotation was 10.6 degrees (range 6 to 17) at C2, 9.1 degrees (5 to 13) at C3, 7.8 degrees (6 to 9) at C4, 6.7 degrees (4 to 11) at C5, 4.9 degrees (2 to 8) at C6, and 2.8 degrees (0 to 4) at C7. Vertebrae in the upper and middle cervical spine rotated more than the lower cervical spine vertebrae. Of the 76 pedicle screws inserted into vertebrae between C2 and C7, 74 screws (97.4%) were classified as grade 1 (no pedicle perforation). In this study, upper and middle cervical vertebrae in patients with neck injuries rotated more than the lower vertebrae. We should be especially careful of cervical rotation during screw insertion from C2 to C6, so as to prevent vertebral artery injury.

Validity of the Posterior-Anterior Middle Cervical Spine Gliding Test for the Examination of Intervertebral Joint Hypomobility in Mechanical Neck Pain

Objective The purpose of this study was to determine if the posterior-anterior cervical gliding test is a valid test as compared with dynamic radiographic assessment in flexion/extension as tool for the manual diagnosis of intervertebral joint hypomobility in the midcervical spine in patients with mechanical neck pain. Methods The study was done according to Standards for Reporting of Diagnostic Accuracy guidelines. Fifty patients with mechanical neck pain participated. An examiner performed a posterior-anterior cervical spine gliding to determine the presence of joint hypomobility over the C3-C4, C4-C5, and C5-C6 levels. Two dynamic radiographs in flexion/extension of the neck were obtained from each patient. The angle resulting from the intersection of 2 lines traced between 2 consecutive vertebrae was considered the degree of intersegmental motion of flexion-extension between those vertebrae. Intersegmental motion showing radiographic data below mean − SD from normative data was considered to reflect hypomobility. Differences between hypomobile and not hypomobile segments were assessed with the 2-tailed unpaired Student t test. Sensitivity, specificity, positive predictive value, and negative predictive value were also obtained. Results At all cervical segments, those patients diagnosed with hypomobility showed significantly ( P < .001) lower radiographic motion (C3-C4: 12.4° ± 2.7°, C4-C5: 14.5° ± 2.6°, C5-C6: 15.0° ± 4.8°) compared with those patients not diagnosed with hypomobility (C3-C4: 17.6° ± 3.8°, C4-C5: 19.4° ± 3.4°, C5-C6: 21.0° ± 3.8°). The C3-C4 and C4-C5 levels had high sensitivity (>80%) and specificity (>70%), whereas C5-C6 showed high sensitivity (100%) but low specificity (41%). Conclusions The posterior-anterior cervical gliding test was as good as dynamic radiographic assessment for the diagnosis of intervertebral hypomobility in the midcervical spine in this group of subjects.

Surgical treatment of upper, middle and lower cervical injuries and non-unions by anterior procedures

The goals of any treatment of cervical spine injuries are: return to maximum functional ability, minimum of residual pain, decrease of any neurological deficit, minimum of residual deformity and prevention of further disability. The advantages of surgical treatment are the ability to reach optimal reduction, immediate stability, direct decompression of the cord and the exiting roots, the need for only minimum external fixation, the possibility for early mobilisation and clearly decreased nursing problems. There are some reasons why those goals can be reached better by anterior surgery. Usually the bony compression of the cord and roots comes from the front therefore anterior decompression is usually the procedure of choice. Also, the anterior stabilisation with a plate is usually simpler than a posterior instrumentation. It needs to be stressed that closed reduction by traction can align the fractured spine and indirectly decompress the neural structures in about 70%. The necessary weight is 2.5 kg per level of injury. In the upper cervical spine, the odontoid fracture type 2 is an indication for anterior surgery by direct screw fixation. Joint C1/C2 dislocations or fractures or certain odontoid fractures can be treated with a fusion of the C1/C2 joint by anterior transarticular screw fixation. In the lower and middle cervical spine, anterior plating combined with iliac crest or fibular strut graft is the procedure of choice, however, a solid graft can also be replaced by filled solid or expandable vertebral cages. The complication of this surgery is low, when properly executed and anterior surgery may only be contra-indicated in case of a significant lesion or locked joints.