Cervical Spine Muscle-Tendon Unit Length Differences Between Neutral and Forward Head Postures: Biomechanical Study Using Human Cadaveric Specimens

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.

The linear intra-articular motions of the temporomandibular joint in individuals with severe forward head posture: A cross-sectional study

BACKGROUND

The cervical vertebrae and the temporomandibular joint (TMJ) may be linked through their common muscles.

OBJECTIVES

The aim of the present study was to compare the linear intra-articular motions of the TMJ between individuals with the normal craniocervical posture (CCP) and severe forward head posture (FHP).

DESIGN

Cross-sectional study.

METHODS

Volunteers (N = 38) were equally assigned to either the severe FHP group or the normal CCP group according to their craniovertebral angle (CVA). The CVA angles greater than 49° were considered as the normal CCP while angles between 44 and 40° were regarded as the severe FHP. The TMJ was imaged at the closed, median, and maximum open positions of the mouth using an ultrasound machine with a 7.5 MHz linear transducer in the sitting position. The best-fitting curve in the contour registration method was employed to measure displacement of the mandibular condyle on the transverse and vertical axes.

RESULTS

The forward displacement of the mandibular condyle in the severe FHP group was significantly (p-value = 0.037) reduced compared to the normal CCP group at maximum open position of the mouth, while no significant difference was revealed at closed (p-value = 0.937) or median open (p-value = 0.699) positions. The perpendicular displacement of the mandibular condyle exhibited no significant (p-value>0.107) difference between groups at any mouth position.

DISCUSSION

The current study demonstrated, for the first time, that severe FHP may impact the intra-articular motion of the TMJ. This study presumed that individuals with severe FHP may encounter a force imbalance in the anterior-posterior direction.

Magnetic resonance imaging-based classification of the myodural bridge complex and its influencing factors

Cerebrospinal fluid (CSF) circulation is considered the third circulation of the human body. Recently, some scholars have proposed the myodural bridge (MDB) as a novel power source for CSF flow. Moreover, the suboccipital muscles can exert a driving force on the CSF via the MDB. This hypothesis is directly supported by head rotation and nodding movements, which can affect CSF circulation. The MDB has been validated as a normal structure in humans and mammals. In addition, the fusion of MDB fibers of different origins that act in concert with each other forms the MDB complex (MDBC). The MDBC may be associated with several CSF disorder-related neurological disorders in clinical practice. Therefore, the morphology of the MDBC and its influencing factors must be determined. In this study, T2-weighted imaging sagittal images of the cervical region were analyzed retrospectively in 1085 patients, and magnetic resonance imaging (MRI) typing of the MDBC was performed according to the imaging features of the MDBC in the posterior atlanto-occipital interspace (PAOiS) and posterior atlanto-axial interspace (PAAiS). The effects of age and age-related degenerative changes in the cervical spine on MRI staging of the MDBC were also determined. The results revealed four MRI types of the MDBC: type A (no MDBC hyposignal shadow connected to the dura mater in either the PAOiS or PAAiS), type B (MDBC hyposignal shadow connected to the dura mater in the PAOiS only), type C (MDBC hyposignal shadow connected to the dura mater in the PAAiS only), and type D (MDBC hyposignal shadow connected to the dura mater in both the PAOiS and PAAiS). The influencing factors for the MDBC typing were age (group), degree of intervertebral space stenosis, dorsal osteophytosis, and degenerative changes in the cervical spine (P < 0.05). With increasing age (10-year interval), the incidence of type B MDBC markedly decreased, whereas that of type A MDBC increased considerably. With the deepening of the degree of intervertebral space stenosis, the incidence of type C MDBC increased significantly, whereas that of type A MDBC decreased. In the presence of dorsal osteophytosis, the incidence of type C and D MDBCs significantly decreased, whereas that of type A increased. In the presence of protrusion of the intervertebral disc, the incidence of type B, C, and D MDBCs increased markedly, whereas that of type A MDBC decreased considerably, with cervical degenerative changes combined with spinal canal stenosis. Moreover, the incidence of both type C and D MDBCs increased, whereas that of type A MDBC decreased. Based on the MRI signal characteristics of the dural side of the MDBC, four types of the MDBC were identified. MDBC typing varies dynamically according to population distribution, depending on age and cervical degeneration (degree of intervertebral space stenosis, vertebral dorsal osteophytosis formation, simple protrusion of intervertebral disc, and cervical degeneration changes combined with spinal canal stenosis, except for the degree of protrusion of the intervertebral disc and the degree of spinal canal stenosis); however, it is not influenced by sex.

Effects of Cervical Paravertebral Extensors in Patients with Cervical Ossification of the Posterior Longitudinal Ligament Grouped According to mK-Line

OBJECTIVES

The objective of this study was to quantify the morphology, composition, and asymmetry of the paravertebral extensor muscles (PSEMs) in patients with cervical ossification of the posterior longitudinal ligament (OPLL) who had different modified K-line (mK-line) and the minimum interval between the mK-line and OPLL (INTmin ) values and to investigate the relationship between PSEMs and symptoms and outcomes following laminoplasty. These original findings elucidated that the atrophy of PSEMs could predict decompression outcomes and provided a theoretical basis for paraspinal muscle rehabilitation.

METHODS

A total of 94 consecutive patients who underwent laminoplasty for OPLL between January 2020 and January 2022 were enrolled in this retrospective study. The relative cross-sectional areas (rCSA), functional cross-sectional areas (rFCSA), and FCSA/CSA ratio of the multifidus (MF), semispinalis cervicalis (SSCe), semispinalis capitis (SSCa), and splenius capitis (SpCa) were measured at the C3-C7 segments on cervical magnetic resonance imaging (MRI). This study compared the differences between the mK-line (+) group and the mK-line (-) group, as well as between the INTmin  <4 mm group and the INTmin  ≥4 mm group, using the independent t-test or Mann-Whitney test for continuous variables and the χ2 -test for categorical variables. The correlations between the PSEMs and symptoms were analyzed using either the Pearson or Spearman correlation coefficient.

RESULTS

The relative total CSA (rTCSA) of the PSEMs, especially the MF, was significantly smaller in the mK-line (-) group. However, the FCSA/CSA of the right deep extensor muscle (DEM) was larger. The asymmetry of the MF TFCSA/TCSA showed a significant difference between the mK-line groups. In the INTmin  <4 mm group, the PSEMs rCSA and rFCSA were significantly smaller, while the bilateral MF TFCSA/TCSA and right SSCe TFCSA/TCSA were larger. The asymmetry of the superficial extensor muscle rCSA was significantly lower in the group with INTmin  <4 mm. The postoperative modified Japanese Orthopedic Association score (mJOA) and mJOA recovery rate were positively correlated with the INTmin and DEM rCSA and negatively correlated with the asymmetry of MF FCSA/CSA.

CONCLUSIONS

In patients with mK-line (-) or INTmin  <4 mm, the PSEMs were smaller, and the DEM atrophy and composition changes were predominant. The MF asymmetry was higher in patients with mK-lines (-), whereas the SEM atrophy and asymmetry were more prevalent in patients with INTmin  <4 mm. The DEM was related to the preoperative and postoperative mJOA scores. DEM-preserving surgery or DEM-specific rehabilitation exercises can improve the recovery of patients with OPLL during the perioperative period. In addition, attention should be paid to the evaluation of the SEM, especially the SpCa at the C3 and C5 levels.

Is Thoracic Kyphosis Relevant to Pain, Autonomic Nervous System Function, Disability, and Cervical Sensorimotor Control in Patients with Chronic Nonspecific Neck Pain?

There is great interest in thoracic kyphosis, as it is thought to be a contributor to neck pain, neck disability, and sensorimotor control measures; however, this has not been completely investigated in treatment or case control studies. This case control design investigated participants with non-specific chronic neck pain. Eighty participants with a defined hyper-kyphosis (>55°) were compared to eighty matched participants with normal thoracic kyphosis (<55°). Participants were matched for age and neck pain duration. Hyper-kyphosis was further categorized into two distinct types: postural kyphosis (PK) and Scheuermann's kyphosis (SK). Posture measures included formetric thoracic kyphosis and the craniovertebral angle (CVA) to assess forward head posture. Sensorimotor control was assessed by the following measures: smooth pursuit neck torsion test (SPNT), overall stability index (OSI), and left and right rotation repositioning accuracy. A measure of autonomic nervous system function included the amplitude and latency of skin sympathetic response (SSR). Differences in variable measures were examined using the Student's t-test to compare the means of continuous variables between the two groups. One-way ANOVA was used to compare mean values in the three groups: postural kyphosis, Scheuermann's kyphosis, and normal kyphosis group. Pearson correlation was used to evaluate the relationship between participant's thoracic kyphosis magnitude (in each group separately and as an entire population) and their CVA, SPNT, OSI, head repositioning accuracy, and SSR latency and amplitude. Hyper-kyphosis participants had a significantly greater neck disability index compared to the normal kyphosis group (p < 0.001) with the SK group having greatest disability (p < 0.001). Statistically significant differences between the two kyphosis groups and the normal kyphosis group for all the sensorimotor measured variables were identified with the SK group having the most decreased efficiency of the measures in the hyper-kyphosis group, including: SPNT, OSI, and left and right rotation repositioning accuracy. In addition, there was a significant difference in neurophysiological findings for SSR amplitude (entire sample of kyphosis vs. normal kyphosis, p < 0.001), but there was no significant difference for SSR latency (p = 0.07). The CVA was significantly greater in the hyper-kyphosis group (p < 0.001). The magnitude of the thoracic kyphosis correlated with worsening CVA (with the SK group having the smallest CVA; p < 0.001) and the magnitude of the decreased efficiency of the sensorimotor control measures and the amplitude and latency of the SSR. The PK group, overall, showed the greatest correlations between thoracic kyphosis and measured variables. Participants with hyper-thoracic kyphosis exhibited abnormal sensorimotor control and autonomic nervous system dysfunction compared to those with normal thoracic kyphosis.

Does Forward Head Posture Influence Somatosensory Evoked Potentials and Somatosensory Processing in Asymptomatic Young Adults?

The current investigation used somatosensory evoked potentials (SEPs) to assess differences in sensorimotor integration and somatosensory processing variables between asymptomatic individuals with and without forward head posture (FHP). We assessed different neural regions of the somatosensory pathway, including the amplitudes of the peripheral N9, spinal N13, brainstem P14, peak-to-peak amplitudes of parietal N20 and P27, and frontal N30 potentials. Central conduction time (N13-N20) was measured as the difference in peak latencies of N13 and N20. We measured these variables in 60 participants with FHP defined as a craniovertebral angle (CVA) < 50° and 60 control participants matched for age, gender, and body mass index (BMI) with normal FHP defined as CVA > 55°. Differences in variable measures were examined using the parametric t-test. Pearson's correlation was used to evaluate the relationship between the CVA and sensorimotor integration and SEP measurements. A generalized linear model (GLM) was used to compare the SEP measures between groups, with adjustment for educational level, marital status, BMI, and working hours per week. There were statistically significant differences between the FHP group and control group for all sensorimotor integration and SEP processing variables, including the amplitudes of spinal N13 (p < 0.005), brainstem P14 (p < 0.005), peak-to-peak amplitudes of parietal N20 and P27 (p < 0.005), frontal N30 potentials (p < 0.005), and the conduction time N13-N20 (p = 0.004). The CVA significantly correlated with all measured neurophysiological variables indicating that as FHP increased, sensorimotor integration and SEP processing became less efficient. FHP group correlations were: N9 (r = -0.44, p < 0.001); N13 (r = -0.67, p < 0.001); P14 (r = -0.58, p < 0.001); N20 (r = -0.49, p = 0.001); P27 (r = -0.58, p < 0.001); N30 potentials (r = -0.64, p < 0.001); and N13-N20 (r = -0.61, p < 0.001). GLM identified that increased working hours adversely affected the SEP measures (p < 0.005), while each 1° increase in the CVA was associated with improved SEP amplitudes and more efficient central conduction time (N13-N20; p < 0.005). Less efficient sensorimotor integration and SEP processing may be related to previous scientific reports of altered sensorimotor control and athletic skill measures in populations with FHP. Future investigations should seek to replicate our findings in different spine disorders and symptomatic populations in an effort to understand how improving forward head posture might benefit functional outcomes of patient care.

Comparison of Sensorimotor Integration and Skill-Related Physical Fitness Components Between College Athletes With and Without Forward Head Posture

OBJECTIVE

To evaluate sensorimotor integration and skill-related physical fitness components for participants with forward head posture (FHP) compared with strictly matched controls with normal head alignment.

MATERIAL AND METHODS

We measured FHP, sensorimotor processing, and skill-related physical fitness variables in 50 participants with FHP and in 50 participants matched for age, gender, and body mass index with normal FHP, defined as having a craniovertebral angle >55°. Sensorimotor processing and integration variables were: (1) amplitudes of the spinal N13, (2) brainstem P14, (3) parietal N20 and P27, and (4) frontal N30 potentials. The skill-related physical fitness variables selected for the study were (1) T-test agility, (2) leg power, (3) stork static balance test, and (4) Y-balance test.

RESULTS

There was a statistically significant difference between the FHP group and control group for the sensorimotor integration variable: frontal N30 potentials (P < .05). Additionally, between-group differences were found for the sensorimotor processing variables: amplitudes of spinal N13, brainstem P14, and parietal N20, and P27 (P < .05). Statistically significant differences between groups for the skill-related physical fitness variables were also identified: T-test agility, leg power, stork static balance test, and Y-balance test (P < .05). The magnitude of the craniovertebral angle showed a correlation with all measured variables (P < .05).

CONCLUSION

College athletes with FHP exhibited altered sensorimotor processing and integration measurements and less efficient skill-related physical fitness compared with athletes with normal sagittal head posture alignment.

Prevalence of text neck posture, smartphone addiction, and its association with neck disorders among university students in the Kingdom of Saudi Arabia during the COVID-19 pandemic

The smartphone emerges as an inevitable gadget in modern society and its increased usage results in neck disorders among its users. However, the factors associated with neck disorders among smartphone users are ambiguous and less explored in the literature. The purpose of this research was to determine the prevalence of text neck posture, smartphone addiction/overuse, and its association with neck disorders among university students in the Kingdom of Saudi Arabia during the COVID-19 pandemic. A total of 313 university students who were aged 18 years and older, owned a smartphone, and used it during the preceding 12 months participated in this cross-sectional study. A self-administered questionnaire was used to collect data regarding the prevalence of text neck posture, smartphone addiction/overuse, neck disorders, and the level of physical activity. Binary logistic regression was used to determine the association between the prevalence of neck disorders and text neck posture, smartphone addiction/overuse, and level of physical activity. The 12 months prevalence of neck disorders due to smartphone use among the participants was found to be 46%. The neck disorders were more prevalent among participants who reported text neck posture (P < 0.001) and categorized as smartphone-addicted/overuse (P < 0.001). Measures to promote the awareness of healthy use of smartphones including postural education and to decrease its screen time are warranted to reduce neck disorders.

Suboccipital Muscles, Forward Head Posture, and Cervicogenic Dizziness

Dizziness or vertigo can be caused by dysfunction of the vestibular or non-vestibular systems. The diagnosis, treatment, and mechanism of dizziness or vertigo caused by vestibular dysfunction have been described in detail. However, dizziness by the non-vestibular system, especially cervicogenic dizziness, is not well known. This paper explained the cervicogenic dizziness caused by abnormal sensory input with references to several studies. Among head and neck muscles, suboccipital muscles act as stabilizers and controllers of the head. Structural and functional changes of the suboccipital muscles can induce dizziness. Especially, myodural bridges and activation of trigger point stimulated by abnormal head posture may be associated with cervicogenic dizziness.

The relationship between forward head posture, postural control and gait: A systematic review

BACKGROUND

Forward head posture (FHP) is a common postural deviation. An increasing number of studies have reported that people with FHP present with impaired postural control and gait; however, there is conflicting evidence. A systematic review focusing on these relationships has been unavailable to date.

RESEARCH QUESTION

Is there a relationship between FHP, postural control and gait?

METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement (PROSPERO ID: CRD42021231908). Web of Science, PubMed, Scopus, and CINAHL Plus (via EBSCO) were systematically searched, and a manual search was performed using the reference lists of included studies. Eligible studies included observational studies addressing the relationship between FHP, postural control and/or gait. Quality assessment was conducted using the Joanna Briggs Institute Critical Appraisal Checklist for Cross-Sectional Studies.

RESULTS

Nineteen studies were selected for this review. Consistent evidence supported that people with FHP had significant alterations in limits of stability (n = 3), performance-based balance (n = 3), and cervical proprioception (n = 4). Controversial evidence existed for a relationship of FHP with static balance (n = 4) and postural stability control (n = 4). Limited evidence existed to support an alteration in gait and vestibular function. Three studies on induced FHP consistently identified no reduced postural control.

SIGNIFICANCE

Current evidence supports an association between FHP and a detrimental alteration in limits of stability, performance-based balance, and cervical proprioception. Instead of simply indicating impaired overall balance, the findings of this review indicate that a reduction in specific aspects of the postural control requires to be clarified in clinical evaluation for individuals with FHP, which would facilitate the planning and application of appropriate interventions to prevent dysfunctions and disability.

Temporomandibular Joint Disk Displacements in Class II Malocclusion and Cervical Spine Alterations: Systematic Review and Report of a Hypodivergent Case with MRI Bone and Soft Tissue Changes

(1) Background: This study aimed to perform a literature review related to disk displacement (DD) in class II malocclusion or cervical vertebrae position alterations and to report a hypodivergent case with cervical pain and right anterolateral DD with reduction, left anterolateral DD with reduction, and left joint effusion. (2) Methods: A structured electronic search was conducted between March 2022 and April 2022, without time limits, following PRISMA guidelines, in the following databases: PubMed, Scopus, Embase and Cochrane; the terms “disc displacement”, “disk displacement”, “temporomandibular joint”, “class II malocclusion” and “cervical vertebrae” are searched. (3) Results: the following thirteen publications are included in this review: two prospective studies and eleven cross-sectional studies; for evaluating disk position, eight included publications used magnetic resonance imaging (MRI), whilst six studies used lateral cephalogram to determine craniofacial morphology and relationships between the cranial base, vertical skeletal pattern, maxilla and mandible. (4) Conclusions: although the literature still shows contradictory opinions, a relationship between temporomandibular disorders and cervical posture has been shown in the presented case as well as in the literature review.

Evidence-Based Corrective Exercise Intervention for Forward Head Posture in Adolescents and Young Adults Without Musculoskeletal Pathology: A Critically Appraised Topic

Clinical Scenario: Habitual overuse of cellphones is on the rise among adolescents and young adults. Those who maintain a flexed neck posture when using a cellphone for extended periods possess an elevated risk for developing forward head posture (FHP). Chronic FHP can lead to painful medical disorders affecting the head, neck, and shoulders. Both stretching and strengthening exercises are advocated interventions to address this postural abnormality; however, due to a wide range of corrective exercise programming in the literature, the decision for which exercises to prescribe for this condition can be challenging for clinicians. Clinical Question: For adolescents and young adults without musculoskeletal pathology, what are the most frequent stretching and strengthening exercises incorporated into effective FHP intervention programs supported by current randomized control trials? Summary of Key Findings: A combined total of 5 stretches and 8 strengthening exercises were identified across 3 studies of level 1b evidence that successfully impacted FHP using a combined stretching and strengthening corrective exercise intervention. The supine chin tuck and a sternocleidomastoid stretch were utilized in all 3 studies, while scapular retraction and a pectoralis stretch were included in 2 of the 3 studies. Clinical Bottom Line: Based on the results of this appraisal, the most frequent stretches and strengthening exercises incorporated into effective FHP intervention programs supported by current randomized control trials focused on adolescents or young adults without musculoskeletal pathology include a sternocleidomastoid stretch, pectoralis stretch, the supine chin tuck, and scapular retraction. Strength of Recommendation: There is "Good" to "Excellent" evidence from 3 level 1b randomized control trials to support the inclusion of a sternocleidomastoid stretch, pectoralis stretch, the supine chin tuck, and scapular retraction exercises into a corrective exercise program to address forward head posture.

Changes in deep neck muscle length from the neutral to forward head posture. A cadaveric study using Thiel cadavers

Forward head posture (FHP) is one of the most common postural deviations. Deep neck muscle imbalance of individuals with FHP is of primary concern in clinical rehabilitation. However, there is scarce quantitative research on changes in deep neck muscle length with the head moving forward. This study aimed to investigate changes in deep neck muscle length with different severity levels of FHP. Six Thiel‐embalmed cadavers (four males and two females) were dissected, and 16 deep neck muscles in each cadaver were modeled by a MicroScribe 3D Digitizer in the neutral head posture, slight FHP, and severe FHP. The craniovertebral angle was used to evaluate the degrees of FHP. Quantitative length change of the deep neck muscles was analyzed using Rhinoceros 3D. In slight FHP significant changes in length occurred in four muscles: two shortened (upper semispinalis capitis, rectus capitis posterior minor) and two lengthened (longus capitis, splenius cervicis). In severe FHP all occipital extensors were significantly shortened (10.6 ± 6.4%), except for obliquus capitis superior, and all cervical extensors were significantly lengthened (4.8 ± 3.4%), while longus capitis (occipital flexor) and the superior oblique part of the longus colli (cervical flexor) were lengthened by 8.8 ± 3.8% and 4.2 ± 3.1%, respectively. No significant length change was observed for the axial rotator. This study presents an alternate anatomical insight into the clinical rehabilitation of FHP. Six muscles appear to be important in restoring optimal head posture, with improvements in FHP being related to interventions associated with the occipital and cervical extensors.

Fatty infiltration in cervical flexors and extensors in patients with degenerative cervical myelopathy using a multi-muscle segmentation model

Background

In patients with degenerative cervical myelopathy (DCM) that have spinal cord compression and sensorimotor deficits, surgical decompression is often performed. However, there is heterogeneity in clinical presentation and post-surgical functional recovery.

Objectives

Primary: a) to assess differences in muscle fat infiltration (MFI) in patients with DCM versus controls, b) to assess association between MFI and clinical disability. Secondary: to assess association between MFI pre-surgery and post-surgical functional recovery.

Study design

Cross-sectional case control study.

Methods

Eighteen patients with DCM (58.6 ± 14.2 years, 10 M/8F) and 25 controls (52.6 ± 11.8 years, 13M/12 F) underwent 3D Dixon fat-water imaging. A convolutional neural network (CNN) was used to segment cervical muscles (MFSS- multifidus and semispinalis cervicis, LC- longus capitis/colli) and quantify MFI. Modified Japanese Orthopedic Association (mJOA) and Nurick were collected.

Results

Patients with DCM had significantly higher MFI in MFSS (20.63 ± 5.43 vs 17.04 ± 5.24, p = 0.043) and LC (18.74 ± 6.7 vs 13.66 ± 4.91, p = 0.021) than controls. Patients with increased MFI in LC and MFSS had higher disability (LC: Nurick (Spearman’s ρ = 0.436, p = 0.003) and mJOA (ρ = -0.399, p = 0.008)). Increased MFI in LC pre-surgery was associated with post-surgical improvement in Nurick (ρ = -0.664, p = 0.026) and mJOA (ρ = -0.603, p = 0.049).

Conclusion

In DCM, increased muscle adiposity is significantly associated with sensorimotor deficits, clinical disability, and functional recovery after surgery. Accurate and time efficient evaluation of fat infiltration in cervical muscles may be conducted through implementation of CNN models.

Inter and Intra-Rater Reliability of Measuring Photometric Craniovertebral Angle Using a Cloud-Based Video Communication Platform

Objective:

Due to social distancing guidelines during the Coronavirus (COVID-19) pandemic, most providers and patients have wanted to avoid close contact. This makes physical therapy (PT) assessments difficult because of the lack of empirical evidence about the reliability of various clinical measurements performed in a virtual environment. One such procedure is the photometric measurement of craniovertebral (CV) angle. Craniovertebral angle measurement is usually performed in an outpatient setting and is defined as the acute angle formed between a straight line connecting the spinous process of C7 to the tragus of the ear, and the horizontal line passing through the spinous process of the C7. Although the photometric measurement of CV angles is considered both valid and reliable in the clinics, no empirical evidence exists about the CV angle measurement reliability when performed in a virtual environment. Thus, the purpose of this study was to assess the inter- and intra-rater reliability of photometric CV angle measurement using a cloud-based video communication platform. Number of Subjects: 66 subjects (57 females).

Methods:

All measurements were performed by two final year PT students who had completed the musculoskeletal part of the curriculum and were blinded to each other's measurements. Each subject was photographed in two postures over a HIPAA-compliant video-based telehealth platform: (1) normal/relaxed posture and (2) ideal posture (posture the subject considered good). Student researcher 1 measured the CV angle in both the relaxed posture and ideal posture, while student researcher 2 measured the CV angle only in the relaxed posture. Each subject's CV angle measurement was performed three times on three separate days and the means were used for further analysis. The shape of the CV angle frequency distribution was assessed using kurtosis and skewness values. Rater reliability was assessed using intraclass correlation coefficients (ICC), and interpreted based on the guidelines provided by Portney and Watkins (2009).

Results:

The CV angles were normally distributed in both relaxed and ideal postures. The mean and standard deviation (SD) of relaxed posture was 50.7o ± 6.3o with kurtosis and skewness of 0.67 and −0.74 respectively. The mean and SD of ideal posture was 55.5o ± 5.4o, with kurtosis and skewness of 0.1 and −0.54 respectively. The ICC for inter-rater reliability in the relaxed posture was 0.88 and the ICC for intra-rater reliability for relaxed posture was 0.91.

Conclusions:

Craniovertebral angles were normally distributed in the sample. An acceptable level of inter- and intra-rater reliability can be attained when measuring CV angle using a cloud-based video communication platform.

New methodology to assess in-vivo quality of motion in cervical spine

BACKGROUND

Understanding the kinematics of the spine in the interaction with an implanted device is of utmost importance from a clinical point of view. The characterization of the biomechanical movement of the spine occurring at each functional unit is a difficult task as it involves the measurement of complex patterns of motion while identifying more delicate abnormalities that could result in longer-term disease complications. Center of rotation is a biomechanical parameter that represents the ratio between rotation and translation. It has been recognized as a valid and reliable parameter to identify any delicate abnormal movement of the spine as opposed to the range of motion. However, center of rotation is still not widely used in clinical practice.

METHODS

In this study, an algorithm intended to easily identify an imbalanced spine through the center of rotation calculation and a new parameter called distance to the ellipse is presented. In this new approach the distance to the ellipse is a key parameter which represents the distance of the center of rotation lying outside the ellipse that represents the asymptomatic group, from the ellipse itself.

FINDINGS

The presented algorithm allows the comparison of pre-op and post-op outcomes, and the rapid identification of cases needing more attention.

INTERPRETATION

When a comprehensive analysis is required, a dashboard is provided with detailed information for each functional spine unit at each follow-up appointment. It is found that the new approach has the potential to become a new methodology in clinical practice.

LEVEL OF EVIDENCE

Biomechanical Study.

Interaction between Pain, Disability, Mechanosensitivity and Cranio-Cervical Angle in Subjects with Cervicogenic Headache: A Cross-Sectional Study

The relationship between the forward head posture and mechanosensitivity in subjects with a cervicogenic headache (CGH) remains uncertain. The aim of the study was to evaluate if there was a relationship between the tissue mechanosensitivity and cranio-cervical angle (CCA) that was moderated by pain intensity and/or disability in subjects with CGH. A convenience sample of 102 subjects was recruited. The CCA was measured with photographs, using a postural assessment software. The pain intensity was measured with a visual analogue scale (VAS), and the disability was measured with the Northwick Park Questionnaire. The pressure pain threshold (PPT) was measured at the spinous process of C2, the upper trapezius and splenius capitis muscles, and the median nerve. Simple moderation multiple regression analyses were constructed. There was a positive relationship between PPT at C2 and CCA, but a nonsignificant relationship for the PPT measured at the muscles and median nerve. The effect of PPT at C2 over CCA was moderated by pain intensity (R² = 0.17; R² change = 0.06; p < 0.05) but not disability. The Johnson–Neyman analysis revealed a cut-off point for the statistical significance of 4.66 cm in VAS. There seems to be a positive relationship between PPT at C2 and CCA, which is positively moderated by pain intensity in subjects with CGH.

Does forward head posture change subacromial space in active or passive arm elevation?

Objectives: Forward head posture (FHP) is one of the most common musculoskeletal disorders that appears to affect the shoulder joint through the shared muscles between the head and neck area and the shoulder girdle. The present study compared the acromiohumeral distance between individuals with normal head and neck alignment and those with moderate and severe FHP in active and passive arm elevation.Methods: Based on the craniovertebral angle, 60 volunteers were selected and equally distributed among three groups, including group one with normal head and neck alignment, group two with moderate FHP and group three with severe FHP. The space between the humeral head and the acromion was measured in 10°, 45° and 60° of active and passive arm elevation as the acromiohumeral distance.Results: The acromiohumeral distance was only different between the three groups at 45° arm elevation angle, and this difference was significant between groups one and three. In active and passive arm elevation, increased arm elevation angle reduced the subacromial space significantly. Also, in each arm elevation angle, the subacromial space differed significantly between the active and passive arm elevations.Conclusions: The acromiohumeral distance was significantly lower in the severe FHP group than the group with normal head and neck alignment in the 45° active arm elevation angle, which could be due to the changed tension in tissues between active and passive arm elevation and also the maximum muscle activity in the 45° active arm elevation angle.

Do changes in psychosocial factors, lifestyle factors and sitting posture influence the likelihood of musculoskeletal pain in high school computer users?

OBJECTIVES

Adolescents regularly engage in screen-based activities. Complex factors influence adolescents' growth, and habitual sitting posture. The association between over-time changes in their sitting posture, and upper quadrant musculoskeletal pain (UQMP) is poorly understood. This study tested the association between change over 12 months in seated posture angles (neck flexion [NF]; craniocervical angle [CCA] into flexion and extension; and thoracic flexion [TF]), UQMP, and predictor variables (anxiety and depression; sport activity, music participation; computer use).

METHODS

A one-year prospective longitudinal study enrolled 211 asymptomatic 15-18-year students. 3D motion analysis captured postural angles while students worked on desktop computers, at baseline and 12 months later. Height, weight, computing time, sport and music participation, and depression and anxiety were measured at both time periods. UQMP in the previous month was captured at 12 months. The association between over-time change in sitting posture angles and predictor variables was determined using linear regression analysis (r² ; p-values). The association between predictor variables with UQMP, and predictor variables on the association between postural angles and UQMP was assessed using logistic regression models (Odds Ratios [95%CI]). Significant confounding effects were determined when the addition of a predictor variable to the posture-UQMP model significantly changed the Likelihood Ratio chi square value.

RESULTS

N = 153 students (72%) completed the study (48 with UQMP). Significant associations occurred between head flexion (HF) and body mass index (BMI) (r²⁼ 4.20, p = .01); NF and computer use (r²⁼ 2.87, p = .036) and CCA and music participation (r²⁼ 9.99, p = .047). Music participants and non-participants in sport or music had increased risk of UQMP with CCA changes into flexion (OR 12.0) and TF changes into extension (OR 7.6) respectively.

CONCLUSION

The association between over-time-change in sitting posture angles and UQMP is not influenced by anthropometrics, psychosocial factors or time spent computing. Music students, and students not participating in sport, require further postural analysis.

Effects of carrying school bags on cervical and shoulder posture in static and dynamic conditions in adolescent students

Background Neck and Back Pain in Students is closely related to the school bags that they carry. There is a dearth of literature in terms of postural changes due to school bags in adolescents, especially those discussing postural changes in static and dynamic loading conditions. Objective To assess the effects of weight, position, and time of school bag carriage in static and dynamic conditions on cervical and shoulder posture in adolescent students. Subjects Seventy adolescents (35 Females, 35 Males) between 10 and 15 years of age. Methods: Craniohorizontal Angle, Craniovertebral Angle, Sagittal Shoulder Posture, Anterior Head Alignment were assessed in 7 different conditions using Photographic Method and MB Ruler. Results and Conclusion Significant changes in Sagittal Shoulder Posture and Craniohorizontal Angle were found with unilateral school bag carriage as compared to minimal significant postural changes with bilateral carriage. Maximal significant postural changes, in terms of all outcome measures were noted during loaded dynamic activity. Craniovertebral Angle kept significantly reducing with time. Immediate assessments taken with a school bag weighing 13.5% of the body weight showed a significant decrement in the Craniohorizontal Angle. Even a bag weighing less than 10% of the body weight proved to bring about biomechanical changes, when assessments were taken during the activities that a child has to perform with a school bag (Post Standing, Post Walking, and During Walking).

Influence of Forward Head Posture on Myotonometric Measurements of Superficial Neck Muscle Tone, Elasticity, and Stiffness in Asymptomatic Individuals With Sedentary Jobs

OBJECTIVE

The objective of the study was to assess the influence of forward head posture on the mechanical parameters and pressure pain threshold of superficial neck muscles in clinically nonsymptomatic individuals with sedentary jobs.

METHODS

Twenty-five office workers with forward head posture and 25 office workers with normal head posture were matched for sex, age, body mass index, and the nature and duration of their work and were compared at a single point. The study participants were divided into study groups on the basis of photometric craniovertebral angle measurements. The upper trapezius, sternocleidomastoid, and splenius capitis mechanical properties were assessed in the sitting position. Primary outcome measures were muscle stiffness (N/m), muscle tone (Hz), and muscle elasticity. The secondary variable was perceived pain threshold.

RESULTS

No significant differences between the groups were found for biomechanical properties and perceived pain threshold in the studied muscles.

CONCLUSION

Forward head posture has no impact on muscle stiffness, tone, and elasticity, nor does it increase the pressure sensitivity of superficial neck muscles in healthy, mildly symptomatic office workers. It is most likely that not incorrect posture of the cervical spine, but probably other factors combined with forward head posture, like comorbid acute and chronic cervical pain and musculoskeletal disorders or prolonged sitting, contribute to changes in active myofascial tone and tensegrity as well as increased pressure sensitivity of neck muscles.

Is There Support for the Paradigm 'Spinal Posture as a Trigger for Episodic Headache'? A Comprehensive Review

PURPOSE OF REVIEW

The International Classification of Headache Disorders provides an extensive framework to classify headaches. Physiotherapy is indicated if neuromusculoskeletal dysfunctions are involved in the pathophysiology. Maladaptive postures seem a dominant trigger in tension-type and cervicogenic headache. Yet, outcomes following physiotherapy vary. The absence of protocol studies to identify determinants concerning the role of spinal posture in headache might explain such variability. Hence, multi-dimensional profiling of patients with headache based on interactions between spinal posture, psychosocial and lifestyle factors might be essential. Therefore, the aim of this paper was to perform a comprehensive review to find support for the paradigm of spinal posture triggering episodic headache based on a multi-dimensional view on tension-type and cervicogenic headache including modern pain neuroscience.

RECENT FINDINGS

A review was conducted to support spinal posture-induced episodic headache. Pubmed, Web of Science, Pedro and the Cochrane database were explored based on the following 'Mesh' or 'Topics': 'Headache', 'Posture', 'Spine', 'Psychosocial', 'Lifestyle'. The contemporary review of neuroanatomical, biomechanical and non-nociceptive pathways, with integration of modern pain neuroscience in tension-type and cervicogenic headache, supports spinal posture as a trigger for episodic headache. Maladaptive postures can activate C1-C3 nociceptors. Convergence with trigeminal afferents at the trigeminocervical nucleus could explain spinal headache. Interactions with psychosocial and lifestyle factors might contribute to peripheral and central sensitisation. Neuroanatomical, biomechanical and non-nociceptive pathways seem to justify profiling patients based on a postural trigger. Further research is needed to determine the contribution of postural dysfunctions in headache and the effect of specific interventions.

Postoperative Cervical Sagittal Realignment Improves Patient-Reported Outcomes in Chronic Atlantoaxial Anterior Dislocation

BACKGROUND

Chronic atlantoaxial anterior dislocation (AAD) not only results in myelopathy, but dislocation-related kyphosis also results in cervical malalignment, which permanently affects neck function and patient-reported outcomes (PROs).

OBJECTIVE

To investigate the effect of kyphotic correction on realigning cervical spine and independent cervical alignment parameters, which may be correlated with an improvement of PROs.

METHODS

The study included 21 patients with chronic AAD-related kyphosis who underwent C1-2 reduction and correction surgery. Radiographic parameters were measured to assess cervical realignment preoperatively and postoperatively. Neck disability index (NDI), short form 12 physical component summary (SF-12 PCS), and Japanese Orthopaedic Association (JOA) scores were recorded to reveal changes in PROs. The independent parameters correlated with the improvements of PROs were analyzed.

RESULTS

Of the radiographic parameters, the C1-2 Cobb angle, the C2-7 Cobb angle, thoracic inlet angle, cervical tilt, and T1 slope were significantly changed from -4.0° ± 16.2°, -29.2° ± 11.2°, 73.1° ± 13.3°, 30.4° ± 8.5°, and 29.1° ± 8.8° preoperatively to -13.5° ± 8.1° (P = .005), -18.0° ± 12.0° (P < .001), 67.1° ± 11.6° (P = .042), 23.1° ± 10.3° (P = .007), and 24.0° ± 7.0° (P = .011) at last follow-up, respectively. NDI, JOA, and SF-12 PCS scores were significantly improved postoperatively. The C1-2 Cobb angle was an independent parameter correlated with the improvements in SF-12 PCS, NDI, and JOA scores.

CONCLUSION

Correction and reduction surgery can realign cervical spine in chronic AAD patients. The C1-2 Cobb angle was an independent parameter correlated with the improvements of PROs.

Impaired Trunk Posture in Women With Fibromyalgia

STUDY DESIGN

A cross-sectional study.

OBJECTIVES

The main goal of the study was to analyze posture of Fibromyalgia syndrome (FMS) in women compared with healthy subjects to establish if posture assessment could be useful to characterize the syndrome. Secondarily, we explored the impact of sedentary behavior on trunk posture.

SUMMARY OF BACKGROUND DATA

Pain has been associated with poor static postures, however there is little information on the effect of FMS, which is characterized by widespread pain, on trunk posture.

METHODS

One hundred eighteen women with FMS and 110 healthy counterparts participated in this study, in which trunk posture was assessed. The thoracic kyphosis, forward head position, and shoulder position (basal and maximum protraction) were measured. Further, maximum shoulder protraction and the ability to maintain the cervical and thoracic angle were assessed. To compare the differences in posture depending on the grouping, an independent Student t test was conducted. To analyze the differences between groups in the ability to maintain the position over a period of time and the differences in posture depending on more or less active lifestyles, two multivariate analysis of variance were performed.

RESULTS

The results showed a significantly larger thoracic kyphosis, baseline shoulder protraction and lower craniovertebral angle and maximum protraction in FMG compared with CG (P < 0.05). FMG subjects exhibited an impaired ability to maintain the cervical and thoracic angles, as this varied throughout the test, unlike those of their counterparts. A sedentary lifestyle did not affect trunk posture in the FMS participants.

CONCLUSION

FMS female population present an altered trunk posture and an inability to maintain trunk position. Since this does not appear to be influenced by a more or less active lifestyle, specific treatment programs are needed to manage this clinical condition.

LEVEL OF EVIDENCE

2.

An ultrasonographic investigation of deep neck flexor muscles cross-sectional area in forward and normal head posture

BACKGROUND

As one of the most common work-related musculoskeletal disorders and postural deviations, forward head posture (FHP), is considered to lead to muscle imbalance.

OBJECTIVES

The aim of this study is to investigate the bilateral cross-sectional area (CSA) of the deep neck flexor muscles at rest and during five stages of the craniocervical flexion (CCF) test in individuals with FHP and the controls with normal head posture.

METHODS

Eighteen students with FHP and 18 controls with normal head posture, all females aged 18-35 years, participated in this study. Participants were categorized into two groups based on their craniovertebral angle. The CSA of the deep neck flexors was measured using ultrasonography while participants lay supine on the table with a pressure biofeedback unit placed under their necks in order to let the examiner measure the CSA of the muscles during rest and five stages of the CCF test including 22, 24, 26, 28, and 30 mmHg of the pressure biofeedback unit.

RESULTS

A significant effect of contraction level was observed in both groups, indicating significant increases of the CSA of the deep neck flexors during contraction (F = 64.37, P < 0.001). No significant difference was evident for the CSA of the deep neck flexors between the groups, although the increase in the CSA of the deep neck flexors was up to 28 mmHg in the normal head posture group compared to 26 mmHg in the FHP group.

CONCLUSIONS

The results of the present study showed no significant difference between the performance of the deep neck flexors during the CCF test in FHP and normal head posture individuals, which challenge the common belief of the deep neck flexors weakness in individuals sustaining FHP.

A radiographic investigation of cervical spine kinematics when reading a tablet in a reclined trunk position

The purpose of this study was to use radiographic measurements to compare cervical spine kinematics in various tablet computer reading postures. Radiographs were taken of twenty-two participants reading a tablet computer in five different postures. The lower cervical spine was more flexed in the semi-reclined (-8.2 ± 3.8°) and the reclined (-14.9 ± 4.0°) tablet positions compared to an upright (-4.43 ± 4.8°) tablet posture. Of the tablet reading positions, the reclined position had the lowest gravitational moment arm (5.2 ± 2.3 cm) and a skull angle closest to neutral (-9.4 ± 11.4°), while exhibiting the largest extension in the C1-C2 joint (34.4 ± 9.1°). Altering trunk position when reading a tablet could reduce the load required to support the head, but could put the head in a more forward head posture, stretch the cervical extensor muscles, and potentially result in pain.