Responsiveness of the cervical joint position error test to detect changes in neck proprioception following four weeks of home-based proprioceptive training.

INTRODUCTION: People with chronic neck pain (CNP) commonly exhibit a range of physical impairments including cervical proprioceptive deficits. Assessing proprioception using a head mounted laser to assess joint position error (JPE) is a reliable and valid measure. However, the responsiveness of this measure has not been assessed. OBJECTIVE: To assess the responsiveness of the measure of cervical JPE after a 4-week home-based neck proprioceptive training intervention in people with CNP. DESIGN: An observational study to assess the responsiveness of the measure of cervical JPE. METHODS: The JPE test was assessed in people with CNP before and after 4 weeks of neck proprioception training. JPE was assessed as participants performed neck joint position sense tests for flexion, extension, right rotation, and left rotation in sitting and standing which were performed in a random order. Both the absolute and constant JPE were assessed. The intervention consisted of neck repositioning exercises as well as movement sense exercises. Cohen's d effect size was used to assess the internal responsiveness of the JPE test. The Pearson's correlation was used to assess the change of scores of the laser pointer and measures from inertial measurement units (IMUs) (external responsiveness). RESULTS: After 4 weeks of proprioception training, JPE assessed in sitting reduced from 2.69◦-3.57◦ to 1.88◦-1.98◦ for flexion, extension, and right rotation with large effect sizes (Cohen's d range: 1.25-2.00). For left rotation, JPE reduced from 3.23◦ to 1.9◦, and the effect size was close to being large (Cohen's d: 0.79). When assessed in standing, JPE reduced from 3.49◦-4.52◦ to 1.5◦-2.33◦ with large effect sizes (Cohen's d range: 0.89-1.25) for flexion, extension, right rotation, and left rotation. Large effect sizes were not observed for the constant JPE when assessed in either sitting or standing. The assessment of the external responsiveness revealed weak correlations between the change of scores obtained from the laser pointer and the IMUs for all movements, apart from the constant JPE in sitting for left rotation, which showed a strong correlation (r = 0.7). CONCLUSION: The results of this study showed that the measure of the JPE has sufficient internal responsiveness, however, the external responsiveness was inadequate. Further research is advised.

The effect of suboccipital muscle dysfunction on the biomechanics of the upper cervical spine: a study based on finite element analysis.

OBJECTIVE: Muscle dysfunction caused by repetitive work or strain in the neck region can interfere muscle responses. Muscle dysfunction can be an important factor in causing cervical spondylosis. However, there has been no research on how the biomechanical properties of the upper cervical spine change when the suboccipital muscle group experiences dysfunction. The objective of this study was to investigate the biomechanical evidence for cervical spondylosis by utilizing the finite element (FE) approach, thus and to provide guidance for clinicians performing acupoint therapy. METHODS: By varying the elastic modulus of the suboccipital muscle, the four FE models of C0-C3 motion segments were reconstructed under the conditions of normal muscle function and muscle dysfunction. For the two normal condition FE models, the elastic modulus for suboccipital muscles on both sides of the C0-C3 motion segments was equal and within the normal range In one muscle dysfunction FE model, the elastic modulus on both sides was equal and greater than 37 kPa, which represented muscle hypertonia; in the other, the elastic modulus of the left and right suboccipital muscles was different, indicating muscle imbalance. The biomechanical behavior of the lateral atlantoaxial joint (LAAJ), atlanto-odontoid joint (ADJ), and intervertebral disc (IVD) was analyzed by simulations, which were carried out under the six loadings of flexion, extension, left and right lateral bending, left and right axial rotation. RESULTS: Under flexion, the maximum stress in LAAJ with muscle imbalance was higher than that with normal muscle and hypertonia, while the maximum stress in IVD in the hypertonic model was higher than that in the normal and imbalance models. The maximum stress in ADJ was the largest under extension among all loadings for all models. Muscle imbalance and hypertonia did not cause overstress and stress distribution abnormalities in ADJ. CONCLUSION: Muscle dysfunction increases the stress in LAAJ and in IVD, but it does not affect ADJ.

The effect of a neck-specific exercise program on cervical kinesthesia for patients with chronic whiplash-associated disorders: a case-control study.

INTRODUCTION: Cervical kinesthesia is an important part of movement control and of great importance for daily function. Previous research on kinesthesia in whiplash-associated disorders (WAD) has focused on grades I-II. More research is needed on WAD grade III. The aim of this study was to investigate cervical kinesthesia in individuals with WAD grades II-III before and after a neck-specific exercise intervention and compare them to healthy controls. METHODS: A prospective, case-control study with a treatment arm (n = 30) and a healthy control arm (n = 30) was conducted in Sweden. The WAD group received a neck-specific exercise program for 12 weeks. The primary outcome to evaluate kinesthesia was neck movement control (the Fly test). Secondary outcomes were neck disability, dizziness and neck pain intensity before and after the Fly test. Outcomes were measured at baseline and post-treatment. The control arm underwent measurements at baseline except for the dizziness questionnaire. A linear mixed model was used to evaluate difference between groups (WAD and control) and over time, with difficulty level in the Fly test and gender as factors. RESULTS: Between-group analysis showed statistically significant differences in three out of five kinesthetic metrics (p = 0.002 to 0.008), but not for the WAD-group follow-up versus healthy control baseline measurements. Results showed significant improvements for the WAD-group over time for three out of five kinaesthesia metrics (p < 0.001 to 0.008) and for neck disability (p < 0.001) and pain (p = 0.005), but not for dizziness (p = 0.70). CONCLUSIONS: The exercise program shows promising results in improving kinesthesia and reducing neck pain and disability in the chronic WAD phase. Future research might benefit from focusing on adding kinesthetic exercises to the exercise protocol and evaluating its beneficial effects on dizziness or further improvement in kinesthesia. IMPACT STATEMENT: Kinesthesia can be improved in chronic WAD patients without the use of specific kinesthetic exercises. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03664934), first registration approved 11/09/2018.

Association between clinical biomechanical metrics of cervical spine function and pain or disability in people with neuromusculoskeletal neck pain: Protocol for a systematic review and planned meta-analysis.

INTRODUCTION/BACKGROUND: Neck pain is a burdensome condition associated with pain, disability, and economic cost. Neck pain has been associated with observable changes in neuromuscular function and biomechanics. Prior research shows impairments in kinematic control, including reduced mobility, velocity, and smoothness of cervical motion. However, the strength of association between these impairments and patient-reported pain and disability is unclear rendering development of novel and relevant rehabilitation strategies difficult. The aim of this systematic review is to synthesize existing evidence on the strength of association between clinical biomechanical metrics of neck function (ROM, strength, acceleration, accuracy, smoothness, etc.) and patient-reported neck pain and disability. METHODS/ANALYSIS: This protocol follows Cochrane guidelines and adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P). MEDLINE, EMBASE, CINAHL, SPORTDiscus, Web of Science and Scopus will be searched, along with the gray literature, up to 20 November 2023, using terms and keywords derived from initial scoping searches. Observational studies, including cohorts and cross-sectional studies, that explore associations between clinical biomechanics of the neck and patient-reported outcomes of neck pain or disability will be included. Two reviewers will independently perform study selection, data extraction, and risk of bias assessment (National Institute of Health tool). Data will be synthesized using either a random effects meta-analytic approach or qualitatively using a modified Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach, dependent on the homogeneity of data available. DISCUSSION AND RELEVANCE: This review addresses a gap in the literature by systematically synthesizing findings on the relationship between neck function impairments and patient-reported outcomes. It will identify priorities for neck pain rehabilitation and gaps in current knowledge. DISSEMINATION: The results of this review will be disseminated through a peer-reviewed publication, conference presentation, and lay language summaries posted on an open-access website. TRIAL REGISTRATION: PROSPERO Registration number: CRD42023417317. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023417317.

Unsupervised machine learning for clustering forward head posture, protraction and retraction movement patterns based on craniocervical angle data in individuals with nonspecific neck pain.

OBJECTIVES: The traditional understanding of craniocervical alignment emphasizes specific anatomical landmarks. However, recent research has challenged the reliance on forward head posture as the primary diagnostic criterion for neck pain. An advanced relationship exists between neck pain and craniocervical alignment, which requires a deeper exploration of diverse postures and movement patterns using advanced techniques, such as clustering analysis. We aimed to explore the complex relationship between craniocervical alignment, and neck pain and to categorize alignment patterns in individuals with nonspecific neck pain using the K-means algorithm. METHODS: This study included 229 office workers with nonspecific neck pain who applied unsupervised machine learning techniques. The craniocervical angles (CCA) during rest, protraction, and retraction were measured using two-dimensional video analysis, and neck pain severity was assessed using the Northwick Park Neck Pain Questionnaire (NPQ). CCA during sitting upright in a comfortable position was assessed to evaluate the resting CCA. The average of midpoints between repeated protraction and retraction measures was considered as the midpoint CCA. The K-means algorithm helped categorize participants into alignment clusters based on age, sex and CCA data. RESULTS: We found no significant correlation between NPQ scores and CCA data, challenging the traditional understanding of neck pain and alignment. We observed a significant difference in age (F = 140.14, p < 0.001), NPQ total score (F = 115.83, p < 0.001), resting CCA (F = 79.22, p < 0.001), CCA during protraction (F = 33.98, p < 0.001), CCA during retraction (F = 40.40, p < 0.001), and midpoint CCA (F = 66.92, p < 0.001) among the three clusters and healthy controls. Cluster 1 was characterized by the lowest resting and midpoint CCA, and CCA during pro- and -retraction, indicating a significant forward head posture and a pattern of retraction restriction. Cluster 2, the oldest group, showed CCA measurements similar to healthy controls, yet reported the highest NPQ scores. Cluster 3 exhibited the highest CCA during protraction and retraction, suggesting a limitation in protraction movement. DISCUSSION: Analyzing 229 office workers, three distinct alignment patterns were identified, each with unique postural characteristics; therefore, treatments addressing posture should be individualized and not generalized across the population.

The role of the deep cervical extensor muscles in multi-directional isometric neck strength.

Clinical management of whiplash-associated disorders is challenging and often unsuccessful, with over a third of whiplash injuries progressing to chronic neck pain. Previous imaging studies have identified muscle fat infiltration, indicative of muscle weakness, in the deep cervical extensor muscles (multifidus and semispinalis cervicis). Yet, kinematic and muscle redundancy prevent the direct assessment of individual neck muscle strength, making it difficult to determine the role of these muscles in motor dysfunction. The purpose of this study was to determine the effects of deep cervical extensor muscle weakness on multi-directional neck strength and muscle activation patterns. Maximum isometric forces and associated muscle activation patterns were computed in 25 test directions using a 3-joint, 24-muscle musculoskeletal model of the head and neck. The computational approach accounts for differential torques about the upper and lower cervical spine. To facilitate clinical translation, the test directions were selected based on locations where resistance could realistically be applied to the head during clinical strength assessments. Simulation results reveal that the deep cervical extensor muscles are active and contribute to neck strength in directions with an extension component. Weakness of this muscle group leads to complex compensatory muscle activation patterns characterized primarily by increased activation of the superficial extensors and deep upper cervical flexors, and decreased activation of the deep upper cervical extensors. These results provide a biomechanistic explanation for movement dysfunction that can be used to develop targeted diagnostics and treatments for chronic neck pain in whiplash-associated disorders.

Cervical manipulation versus thoracic or cervicothoracic manipulations for the management of neck pain. A systematic review and meta-analysis.

BACKGROUND: Cervical and thoracic thrust or non-thrust manipulations have shown to be effective in patients with neck pain, but there is a lack of studies comparing both interventions in patients with neck pain. OBJECTIVE: To investigate the effects of cervical thrust or non-thrust manipulations compared to thoracic or cervicothoracic manipulations for improving pain, disability, and range of motion in patients with neck pain. DESIGN: Systematic review and meta-analysis. METHOD: Searches were performed in PubMed, PEDro, Cochrane Library, CINHAL, and Web of Science databases from inception to May 22, 2023. Randomized clinical trials comparing cervical thrust or non-thrust manipulations to thoracic or cervicothoracic manipulations were included. Methodological quality was assessed with PEDro scale, and the certainty of evidence was evaluated using GRADE guidelines. RESULTS: Six studies were included. Meta-analyses revealed no differences between cervical thrust or non-thrust manipulations and thoracic or cervicothoracic manipulations in pain intensity, disability, or cervical range of motion in any plane. The certainty of evidence was downgraded to very low for pain intensity, to moderate or very low for disability and to low or very low for cervical range of motion. CONCLUSION: There is moderate to very low certainty evidence that there is no difference in effectiveness between cervical thrust or non-thrust manipulations and thoracic or cervicothoracic manipulations for improving pain, disability, and range of motion in patients with neck pain. PROSPERO REGISTRATION: CRD42023429933.

Machine learning models for classifying non-specific neck pain using craniocervical posture and movement.

OBJECTIVE: Physical therapists and clinicians commonly confirm craniocervical posture (CCP), cervical retraction, and craniocervical flexion as screening tests because they contribute to non-specific neck pain (NSNP). We compared the predictive performance of statistical machine learning (ML) models for classifying individuals with and without NSNP using datasets containing CCP and cervical kinematics during pro- and retraction (CKdPR). DESIGN: Exploratory, cross-sectional design. SETTING AND PARTICIPANTS: In total, 773 public service office workers (PSOWs) were screened for eligibility (NSNP, 441; without NSNP, 332). METHODS: We set up five datasets (CCP, cervical kinematics during the protraction, cervical kinematics during the retraction, CKdPR and combination of the CCP and CKdPR). Four ML algorithms-random forest, logistic regression, Extreme Gradient boosting, and support vector machine-were trained. MAIN OUTCOME MEASURES: Model performance were assessed using area under the curve (AUC), accuracy, precision, recall and F1-score. To interpret the predictions, we used Feature permutation importance and SHapley Additive explanation values. RESULTS: The random forest model in the CKdPR dataset classified PSOWs with and without NSNP and achieved the best AUC among the five datasets using the test data (AUC, 0.892 [good]; F1, 0.832). The random forest model in the CCP dataset had the worst AUC among the five datasets using the test data [AUC, 0.738 (fair); F1, 0.715]. CONCLUSION: ML performance was higher for the CKdPR dataset than for the CCP dataset, suggesting that ML algorithms are more suitable than classical statistical methods for developing robust models for classifying PSOWs with and without NSNP.

Corticospinal inhibition investigated in relation to upper extremity motor function in cervical spinal cord injury.

OBJECTIVE: Corticospinal inhibitory mechanisms are relevant to functional recovery but remain poorly understood after spinal cord injury (SCI). Post-injury characteristics of contralateral silent period (CSP), a measure of corticospinal inhibition evaluated using transcranial magnetic stimulation (TMS), is inconsistent in literature. We envisioned that investigating CSP across muscles with varying degrees of weakness may be a reasonable approach to resolve inconsistencies and elucidate the relevance of corticospinal inhibition for upper extremity function following SCI. METHODS: We studied 27 adults with chronic C1-C8 SCI (age 48.8 ± 16.1 years, 3 females) and 16 able-bodied participants (age 33.2 ± 11.8 years, 9 females). CSP characteristics were assessed across biceps (muscle power = 3-5) and triceps (muscle power = 1-3) representing stronger and weaker muscles, respectively. We assessed functional abilities using the Capabilities of the Upper Extremity Test (CUE-T). RESULTS: Participants with chronic SCI had prolonged CSPs for biceps but delayed and diminished CSPs for triceps compared to able-bodied participants. Early-onset CSPs for biceps and longer, deeper CSPs for triceps correlated with better CUE-T scores. CONCLUSIONS: Corticospinal inhibition is pronounced for stronger biceps but diminished for weaker triceps muscle in SCI indicating innervation relative to the level of injury matters in the study of CSP. SIGNIFICANCE: Nevertheless, corticospinal inhibition or CSP holds relevance for upper extremity function following SCI.

Actualización sobre el síndrome de Eagle y sus complicaciones neurocardiológicas: casos clínicos / An update on Eagle´s syndrome and its neuro-cardiological complications: clinical cases

El síndrome de Eagle o síndrome estilohioideo o sín-drome de la arteria carótida es un trastorno que se origina por la mineralización y elongación del pro-ceso estiloides. Factores traumáticos agudos y cró-nicos, así como otras teorías, han sido propuestos para explicar la etiología y patogenia de esta altera-ción. El conjunto de síntomas puede incluir: dolor fa-ríngeo, odinofagia, disfagia, cefalea, con irradiación a oreja y zona cervical. Si bien existen varias clasifi-caciones, de manera universal se acepta que existen principalmente dos formas de presentación de esta patología: el tipo I o clásico, generalmente asociado a un trauma faríngeo y acompañado de dolor en la zona faríngea y cervical, y el tipo II o carotídeo, que sue-le presentar molestia cervical, cefalea y alteración de la presión arterial, con riesgo de daño de la ac-tividad cardíaca. La identificación de este síndrome suele ser confusa dada la similitud de los síntomas con otras afecciones. El diagnóstico debe realizarse en base a los síntomas y a los estudios por imágenes específicos. El tratamiento puede ser conservador y actuar simplemente sobre los síntomas, o bien, qui-rúrgico. El objetivo del presente trabajo es realizar una revisión actualizada de la literatura sobre el sín-drome de Eagle y presentar tres casos clínicos con distintas manifestaciones (AU)

Eagle's syndrome or styloid syndrome or stylo-carotid artery syndrome is a disease caused by mineralization and elongation of the styloid process. Acute and chronic traumatic factors, along with other hypothesis, have been proposed to explain the aetiology and pathogenesis of this condition. Symptoms can include: pharynx pain, odynophagia, dysphagia, headache, with radiating pain to the ear and neck. Despite there are several classifications, it is universally accepted that this pathology can present in two forms: the type I or classic, generally associated to tonsillar trauma and characterized by pharyngeal and neck pain, and the type II or carotid artery type, which frequently presents with neck pain, headache, blood pressure variation, with risk of damage to cardiac function. Identifying of Eagle's syndrome is often confusing because some symptoms are shared with other pathologies. Diagnosis must be made on the basis of symptoms and imaging studies. Treatment can be conservative, acting only on symptoms, or surgical. The aim of this paper is to provide an updated review of the literature on Eagle syndrome and to present three clinical cases with different manifestations (AU)

Clinical Evaluation of Neck in Patients with Proprioceptive Cervicogenic Dizziness.

OBJECTIVE: To establish a functional connection between neck physical evaluations, dizziness discomfort and image findings among subjects diagnosed with proprioceptive cervical dizziness. METHODS: After exclusion of peripheral vestibular disorders, 20 subjects with proprioceptive cervical dizziness hypothesis were selected. A Visual Analogue Scale (VAS) was used to quantify pain and vertigo. The active neck Range of Motion (ROM) and the Muscle Strength (MS) of the neck region were examined. The manipulation of vertebral bodies by the Maitland method and imaging scan were performed. RESULTS: A positive correlation between pain and vertigo VAS scores was found. The ROM of the cervical spine was limited and vertebral joint movement was restricted, especially at C3 and C5. No loss of MS was noticed. CONCLUSIONS: Proprioceptive cervical dizziness is usually an exclusion diagnosis among episodic chronic vertigos. Characteristically, it is reported by patients as instability or vertigo in crises. It is directly related to the neck ache severity and worsens with neck movements. The common pattern on clinical examination includes restriction and pain during neck flexion without loss of MS. Reduction of joint mobility and pain are also observed, especially at C3 and C54 kHz.

The effect of mind-body exercise on cervical spine mobility of people with neck discomfort: A systemic review and meta-analysis of randomised controlled trials.

BACKGROUND: Long-term and high-intensity work can lead to considerable discomfort in people's cervical spines. OBJECTIVES: This study sought to explore the effect of mind-body exercise intervention on the cervical spine mobility of people with neck discomfort through meta-analysis. METHODS: This study's researchers were searched a total of five research databases for data retrieval: China National Knowledge Infrastructure (from 1979), Web of Science (from 1950), PubMed (from 1965), Cochrane (from 1991), and EBSCO (from 1949) (Date of retrieval: March 10, 2021). Two authors independently searched literature records, scanned titles, abstracts, and full texts, collected data, and assessed materials for risk of bias. Stata14.0 software was used for the data analysis (Registration number: INPLASY202140126). RESULTS: Four articles were finally included with a total of 208 participants, and their age range was 18-65 years old. (1) Mind-body exercise intervention had a significant improving effect on Cervical extension, effect size of [SMD = 0.51 (95% CI 0.13 to 0.88), p <0.01; I2 = 45.2%], there was moderate heterogeneity; Mind-body exercise intervention had a significant improving effect on Cervical flexion, effect size of [SMD = 0.61 (95% CI 0.32 to 0.90), p <0.01; I2 = 5.7%], no heterogeneity; (2) Mind-body exercise intervention was no effect on the other four cervical range of motions; (3) The difference in participant's neck discomfort was the source of heterogeneity, and all results had the potential risk of publication bias. CONCLUSION: This study showed that mind-body exercise had a positive effect on the extension and flexion of people with neck discomfort. However, further research and more reliable evidence were needed to prove that mind-body exercise could be used for the treatment of neck discomfort.

Comparison of laminoplasty and posterior fusion surgery for cervical ossification of posterior longitudinal ligament.

This prospective multicenter study, established by the Japanese Ministry of Health, Labour and Welfare and involving 27 institutions, aimed to compare postoperative outcomes between laminoplasty (LM) and posterior fusion (PF) for cervical ossification of the posterior longitudinal ligament (OPLL), in order to address the controversy surrounding the role of instrumented fusion in cases of posterior surgical decompression for OPLL. 478 patients were considered for participation in the study; from among them, 189 (137 and 52 patients with LM and PF, respectively) were included and evaluated using the Japanese Orthopaedic Association (JOA) scores, the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and radiographical measurements. Basic demographic and radiographical data were reviewed, and the propensity to choose a surgical procedure was calculated. Preoperatively, there were no significant differences among the participants in terms of patient backgrounds, radiographical measurements (K-line or cervical alignment on X-ray, OPLL occupation ratio on computed tomography, increased signal intensity change on magnetic resonance imaging), or clinical status (JOA score and JOACMEQ) after adjustments. The overall risk of perioperative complications was found to be lower with LM (odds ratio [OR] 0.40, p = 0.006), and the rate of C5 palsy occurrence was significantly lower with LM (OR 0.11, p = 0.0002) than with PF. The range of motion (20.91° ± 1.05° and 9.38° ± 1.24°, p < 0.0001) in patients who had PF was significantly smaller than in those who had LM. However, multivariable logistic regression analysis showed no significant difference among the participants in JOA score, JOA recovery rate, or JOACMEQ improvement at two years. In contrast, OPLL progression was greater in the LM group than in the PF group (OR 2.73, p = 0.0002). Both LM and PF for cervical myelopathy due to OPLL had resulted in comparable postoperative outcomes at 2 years after surgery.

Evaluation of the early cervical structural change in patients with non-radiographic axial spondyloarthropathy.

In this double-blind, controlled, cross-sectional study, we compared structural changes in the cervical vertebrae of patients with nonradiographic axial spondyloarthropathy (nr-axSpA), patients with ankylosing spondylitis (AS), and a control group. We used the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) to determine whether the involvement of the cervical spine occurs earlier and is more severe than that of the lumbar spine in axial spondyloarthropathy (axSpA). A statistically significant difference was found in the total mSASSS between the AS and nr-axSpA groups (p = 0.038), but not in the cervical and lumbar mSASSS. Although the duration of the symptoms was shorter in the nr-axSpA group than in the AS group, no statistically significant difference was found in the cervical mSASSS between the AS and nr-axSpA groups. In both the AS and nr-axSpA groups, the cervical mSASSS values were found to be higher than the lumbar mSASSS values for the majority of the patients (82.8 and 89.5%, respectively). This may indicate that structural changes in the cervical spine occur during an early period of axSpA.

Impact of Cervical Spine Rehabilitation on Temporomandibular Joint Functioning in Patients with Idiopathic Neck Pain.

OBJECTIVE: The aim of this study was to assess the effectiveness of a 3-week rehabilitation programme focusing only on the cervical region, pain intensity, range of motion in the cervical spine, head posture, and temporomandibular joint (TMJ) functioning in subjects with idiopathic neck pain who did not report TMJ pain. DESIGN: A parallel group trial with follow-up. METHODS: The study included 60 participants divided into 2 groups: experimental: n = 25, 27-57 years old, experiencing idiopathic neck pain and who underwent a 3-week rehabilitation programme, and the control, n = 35, 27-47 years, who were cervical pain-free. At baseline and after 3 weeks of treatment in the experimental group and with a 3-week time interval in the control group, pain intensity, head posture in the sagittal plane, range of motion in the cervical spine, and TMJ functioning were evaluated. RESULTS: After 3 weeks of rehabilitation, there was a significant decrease in pain intensity, improved range of motion of the cervical spine and head posture, and improved clinical condition of TMJ in participants with idiopathic neck pain who did not report TMJ pain. CONCLUSION: The study suggested that idiopathic neck pain is associated with limited range of motion in the cervical spine, incorrect head posture, and TMJ dysfunction. Our data suggests that therapy focusing only on the cervical region may improve the clinical condition of the TMJ in subjects with idiopathic neck pain who do not report TMJ pain. These observations could be helpful in physiotherapeutic treatment of neck and craniofacial area dysfunctions. This trial is registered with ISRCTN Registry ISRCTN14511735.

Cervical disc arthroplasty for Klippel-Feil syndrome.

OBJECTIVE: Klippel-Feil syndrome (KFS) is a congenital musculoskeletal condition characterized by improper segmentation of the cervical spine. This study aimed to evaluate outcomes of KFS patients who underwent cervical disc arthroplasty (CDA). METHODS: Consecutive patients who underwent anterior cervical surgery were retrospectively reviewed. Those patients with KFS who received discectomy adjacent to the congenitally fused vertebral segments were extracted and grouped into either the fusion or the CDA group. Clinical and radiological evaluations included visual analog scales, Neck Disability Index (NDI), Japanese Orthopedic Association (JOA) scores, C2-7 range of motion (ROM), C2-7 Cobb angle, C2-7 sagittal vertical axis (SVA), and T1-slope. RESULTS: Among 2320 patients, there were 41 with KFS (prevalence = 1.77%), who were younger than the entire cohort (53.3 vs 56.4 years). Thirty KFS patients had adjacent discs and were grouped into the CDA and fusion groups (14 vs 16). Type-I KFS with C3-4 involvement was the most common for both groups (92.8% vs 81.2% with 57% vs 50%, respectively). Post-operation, both groups demonstrated improvement of all the patient reported outcomes. The C2-7 ROM significantly decreased in the fusion group than that of pre-operation (12.8 ± 6° vs 28.1 ± 11.5°). In contrast, the CDA group successfully preserved C2-7 and segmental ROM without additional complications. CONCLUSIONS: KFS is rare (prevalence = 1.77%) among cervical spine surgery patients, and it rarely affects the overall cervical spinal alignment, except that it decreases segmental mobility. CDA is a feasible option for KFS because it not only avoids long-segment fusion but also preserves segmental and global mobility.

Relationship between cervical curvature and spinal cord drift distance after laminectomy via lateral mass screw fixation and its effect on clinical efficacy.

BACKGROUND: Laminectomy with lateral mass screw fixation (LCS) is considered an effective surgical procedure for cervical spondylotic myelopathy. However, varying degrees of loss of the cervical curvature were noted in some patients postoperatively. The aim of this study was to observe the relationship between cervical curvature and spinal drift distance after LCS and to determine its effect on neurological function, axial symptoms, and C5 palsy. METHODS: A total of 117 consecutive cervical spondylotic myelopathy patients with normal cervical curvature underwent LCS from April 2015 to May 2017 in our institution. Of these patients, 90 patients who accepted to undergo an integrated follow-up were enrolled in this study. The patients were divided into 3 groups based on their postoperative cervical curvature. In group A (28 patients), the cervical curvature became straight postoperatively (0°≤cervical spine angle≤5°); in group B (36 patients), the cervical curvature decreased (5°16.5°). Spinal drift distance, neurological recovery, axial symptoms, and C5 palsy in the patients were recorded and analyzed. RESULTS: Postoperative measurements showed that there was no significant difference in laminectomy width between the groups (P > .05). The cervical spine angle was 2.7°â€Š±â€Š0.5° in group A, 11.2°â€Š±â€Š2.6° in group B, and 20.8°â€Š±â€Š4.1° in group C (P < .05), while the spinal drift distance was 1.2 ±â€Š0.2 mm, 1.8 ±â€Š0.4 mm, and 3.0 ±â€Š0.5 mm, respectively (P < .05). The postoperative Japanese Orthopedic Association score was significantly increased in all groups (P < .05), and there was no significant difference between the groups at different time points (P > .05). However, significant differences were noted between the groups in axial symptoms (P < .05), which were analyzed via the visual analog scale score. The occurrence of C5 palsy in groups A, B, and C was 7.1% (2/28), 8.3% (3/36), and 11.5% (3/26), respectively (P > .05). CONCLUSION: In LCS, the cervical curvature should be maintained at the normal angle to obtain a good spinal cord drift distance and a lower incidence of axial symptoms.

A Dynamic Interbody Cage Improves Bone Formation in Anterior Cervical Surgery: A Porcine Biomechanical Study.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) with a rigid interbody spacer is commonly used in the treatment of cervical degenerative disc disease. Although ACDF relieves clinical symptoms, it is associated with several complications such as pseudoarthrosis and adjacent segment degeneration. The concept of dynamic fusion has been proposed to enhance fusion and reduce implant subsidence rate and post-fusion stiffness; this pilot preclinical animal study was conducted to begin to compare rigid and dynamic fusion in ACDF. QUESTIONS/PURPOSES: Using a pig model, we asked, is there (1) decreased subsidence, (2) reduced axial stiffness in compression, and (3) improved likelihood of bone growth with a dynamic interbody cage compared with a rigid interbody cage in ACDF? METHODS: ACDF was performed at two levels, C3/4 and C5/6, in 10 pigs weighing 48 to 55 kg at the age of 14 to 18 months (the pigs were skeletally mature). One level was implanted with a conventional rigid interbody cage, and the other level was implanted with a dynamic interbody cage. The conventional rigid interbody cage was implanted in the upper level in the first five pigs and in the lower level in the next five pigs. Both types of interbody cages were implanted with artificial hydroxyapatite and tricalcium phosphate bone grafts. To assess subsidence, we took radiographs at 0, 7, and 14 weeks postoperatively. Subsidence less than 10% of the disc height was considered as no radiologic abnormality. The animals were euthanized at 14 weeks, and each operated-on motion segment was harvested. Five specimens from each group were biomechanically tested under axial compression loading to determine stiffness. The other five specimens from each group were used for microCT evaluation of bone ingrowth and ongrowth and histologic investigation of bone formation. Sample size was determined based on 80% power and an α of 0.05 to detect a between-group difference of successful bone formation of 15%. RESULTS: With the numbers available, there was no difference in subsidence between the two groups. Seven of 10 operated-on levels with rigid cages had subsidence on a follow-up radiograph at 14 weeks, and subsidence occurred in two of 10 operated-on levels with dynamic cages (Fisher exact test; p = 0.07). The stiffness of the unimplanted rigid interbody cages was higher than the unimplanted dynamic interbody cages. After harvesting, the median (range) stiffness of the motion segments fused with dynamic interbody cages (531 N/mm [372 to 802]) was less than that of motion segments fused with rigid interbody cages (1042 N/mm [905 to 1249]; p = 0.002). Via microCT, we observed bone trabecular formation in both groups. The median (range) proportions of specimens showing bone ongrowth (88% [85% to 92%]) and bone volume fraction (87% [72% to 100%]) were higher in the dynamic interbody cage group than bone ongrowth (79% [71% to 81%]; p < 0.001) and bone volume fraction (66% [51% to 78%]; p < 0.001) in the rigid interbody cage group. The percentage of the cage with bone ingrowth was higher in the dynamic interbody cage group (74% [64% to 90%]) than in the rigid interbody cage group (56% [32% to 63%]; p < 0.001), and the residual bone graft percentage was lower (6% [5% to 8%] versus 13% [10% to 20%]; p < 0.001). In the dynamic interbody cage group, more bone formation was qualitatively observed inside the cages than in the rigid interbody cage group, with a smaller area of fibrotic tissue under histologic investigation. CONCLUSION: The dynamic interbody cage provided satisfactory stabilization and percentage of bone ongrowth in this in vivo model of ACDF in pigs, with lower stiffness after bone ongrowth and no difference in subsidence. CLINICAL RELEVANCE: The dynamic interbody cage appears to be worthy of further investigation. An animal study with larger numbers, with longer observation time, with multilevel surgery, and perhaps in the lumbar spine should be considered.

Prevalence of sarcopenia in idiopathic dropped head syndrome patients is similar to healthy volunteers.

Dropped head syndrome (DHS) exhibits cervical deformity due to weakness of the cervical extensor group, and sarcopenia is characterized by progressive and systemic reduction in skeletal muscle mass. These clinical finding are associated with reduced activity of daily living, reduced quality of life, and increased risk of mortality. We collected and reviewed prospective registry data for 16 patients with idiopathic DHS continuously collected without dropping out and 32 healthy individuals who matched their gender and age. The prevalence of sarcopenia and body composition data were compared. There were no differences in the prevalence of sarcopenia, appendicular muscle mass, and leg muscle mass between DHS patients and the healthy elderly. Trunk muscle mass in DHS patients was significantly lower than that in healthy individuals. A significant correlation was found between appendicular muscle mass and trunk muscle mass in healthy subjects but not in DHS patients. Sarcopenia was not associated with the onset of idiopathic DHS. The prevalence of sarcopenia was not high in patients with idiopathic DHS due to the preservation of their appendicular skeletal muscle mass. Patients with DHS were characterized by a significant loss of trunk muscle mass that may be related to the disease but not aging.

Epidemiological study of cervical cord compression and its clinical symptoms in community-dwelling residents.

BACKGROUND: Degenerative compressive myelopathy (DCM) is caused by cervical cord compression. The relationship between the magnitude and clinical findings of cervical cord compression has been described in the literature, but the details remain unclear. This study aimed to clarify the relationship between the magnitude and clinical symptoms of cervical cord compression in community-dwelling residents. METHODS: The present study included 532 subjects. The subjective symptoms and the objective findings of one board-certified spine surgeon were assessed. The subjective symptoms were upper extremity pain and numbness, clumsy hand, fall in the past 1 year, and subjective gait disturbance. The objective findings were: Hoffmann, Trömner, and Wartenberg signs; Babinski's and Chaddock's signs; hyperreflexia of the patellar tendon and Achilles tendon reflexes; ankle clonus; Romberg and modified Romberg tests; grip and release test; finger escape sign; and grip strength. Using midsagittal T2-weighted magnetic resonance imaging, the anterior-posterior (AP) diameters (mm) of the spinal cord at the C2 midvertebral body level (DC2) and at each intervertebral disc level from C2/3 to C7/T1 (DC2/3-C7/T1) were measured. The spinal cord compression ratio (R) for each intervertebral disc level was defined and calculated as DC2/3-C7/T1 divided by DC2. The lowest R (LR) along C2/3 to C7/T1 of each individual was divided into 3 grades by the tertile method. The relationship between LR and clinical symptoms was investigated by trend analysis. RESULTS: The prevalence of subjective gait disturbance increased significantly with the severity of spinal cord compression (p = 0.002812), whereas the other clinical symptoms were not significantly related with the severity of spinal cord compression. CONCLUSIONS: The magnitude of cervical cord compression had no relationship with any of the neurologic findings. However, subjective gait disturbance might be a better indicator of the possibility of early stage cervical cord compression.