Cervical spine alignment in the pediatric population: a radiographic normative study of 150 asymptomatic patients

Pediatric spinal alignment and spinal development

Background

Knowledge of the growth spurt and remaining growth is essential for managing musculoskeletal diseases in children. Accurate prediction of curve progression and timely interventions are crucial, particularly for conditions like adolescent idiopathic scoliosis (AIS).

Methods

This study conducted a comprehensive review and synthesis of existing literature on spinal growth, skeletal maturity classifications, and the evolution of sagittal alignment parameters during childhood and adolescence. Key anatomical elements involved in spinal development, natural history of spinal growth, and skeletal maturity assessment systems were analyzed.

Results

The analysis highlighted that key parameters such as Pelvic incidence (PI), Pelvic tilt (PT), and Lumbar lordosis (LL) increase significantly with growth, especially during the pubertal growth spurt. In contrast, Sacral slope (SS) remains relatively constant, and Thoracic kyphosis (TK) shows a slight increase. Additionally, there is a posterior shift in the center of gravity as children grow, reflecting progressive postural maturation. The study also reviewed and compared various maturity classification systems, noting the reliability and clinical implications of systems like the Sanders Maturity Stage (SMS) and Tanner-Whitehouse III.

Conclusions

Reliable maturity classification systems, such as the Sanders Maturity Stage (SMS) and Tanner-Whitehouse III, allow for tailored treatments to individual growth patterns. Integrating these classification systems into clinical practice enables precise prediction of curve progression and timely therapeutic interventions. This includes options from bracing to surgical techniques like growing rods or vertebral body tethering (VBT), with growth modulation being a key factor in achieving successful outcomes.

Horizontal Gaze Assessment: An Extensive Narrative Review

OBJECTIVE

Bipedalism was a significant milestone in the evolutionary development of Homo sapiens sapiens, influencing neocortical evolution and subsequent behavioral changes. Coordinated visual and sensory inputs are crucial for posture, environmental interaction, and surgical planning, with horizontal gaze being a pivotal parameter. This narrative review aims to explore various geometric measures used to assess horizontal gaze in patients, highlighting their applications in surgical planning.

METHODS

A literature review was conducted in indexed databases using Mesh terms like "Cervical Vertebrae" and "Visual Fields" along with keywords such as "horizontal gaze" and "sagittal spine parameters." Among 477 initially identified articles, 41 were selected for inclusion after rigorous filtering.

RESULTS

The most recognized method for assessing horizontal gaze is the Chin Brow Vertical Angle (CBVA), initially described in patients with ankylosing spondylitis. Clinical photography is employed as a tool for CBVA calculation, while other measures like McGregor slope and Slope of the Line of Sight have been considered as alternatives to CBVA. Each method presents its unique advantages and limitations.

CONCLUSIONS

This review highlights the need for further research into horizontal gaze measurement methods. Developing novel approaches to determine horizontal gaze can significantly enhance surgical planning and, consequently, improve patient outcomes. The ongoing exploration of these geometric measures offers promising prospects for advancing the field and optimizing patient care.

Normal spinopelvic parameters and correlation analysis in 217 asymptomatic children

BACKGROUND

Understanding spinal sagittal balance is crucial for assessing and treating spinal deformities in pediatric populations.

OBJECTIVE

The aim of the present observational study is to examine the parameters of sagittal alignment of the regional spine and spinopelvic region in asymptomatic pediatric populations and the characteristics of these parameters with age and sex.

METHODS

We enrolled 217 participants, consisting of 112 males (51.6%) and 105 females (48.4%), aged between 4 and 15 years, with an average age of 12.19 years. Pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, T1 slope, C7 slope, cervical sagittal vertical axis, and C2-7 Cobb angle were measured. Three spine surgeons conducted radiographic measurements utilizing the PACS software. The measurement reliability was assessed through ICCs.

RESULTS

Our results show significant age-related changes in pelvic tilt and cervical sagittal vertical axis, with notable gender differences in pelvic tilt, lumbar lordosis, and thoracic kyphosis. Girls have larger PT, boys have larger cSVA. PI, PT, and cSVA also differ among different age groups. Correlation analysis shows that a series of relationships that align with adult population patterns between pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, and thoracic kyphosis.

CONCLUSION

Significant variations in PT and cSVA across diverse age cohorts highlights notable disparities in the distribution of PT and cSVA values within the pediatric population. Gender-based differences in PT, LL, and TK and correlation in spinopelvic parameter could enhances our understanding of compensatory mechanisms.

Sagittal Full-Spine vs. Sectional Cervical Lateral Radiographs: Are the Measurements of Cervical Alignment Interchangeable?

(1) Background: This study assessed the relationship between cervical spine parameters taken on standing full-spine lateral radiographic images compared to sectional lateral cervical radiographs. (2) Methods: Full-spine (FS) and sectional lateral cervical (LC) radiographs from four spine treatment facilities across the USA retrospectively provided data collected on 220 persons to assess the comparison of three sagittal cervical radiographic measurements between the two views. The measures included cervical lordosis using the absolute rotation angle from C2-C7, sagittal cervical translation of C2-C7, and atlas plane angle to horizontal. Linear correlation and R2 models were used for statistical comparison of the measures for the two views. (3) Results: The mean values of the three measurements were statistically different from each other: C2-C7 translation (FS = 19.84 ± 11.98 vs. LC = 21.18 ± 11.8), C2-C7 lordosis (FS = -15.3 ± 14.63 vs. LC = -18.32 ± 13.16), and atlas plane (FS = -19.99 ± 8.88 vs. LC = -22.56 ± 8.93), where all values were p < 0.001. Weak-to-moderate-to-strong correlations existed between the full-spine and sectional lateral cervical radiographic variables. The R2 values varied based on the measurement were R2 = 0.768 (p < 0.001) for sagittal cervical translation of C2-C7 (strong), R2 = 0.613 (p < 0.001) for the absolute rotation angle C2-C7 (moderate), and R2 = 0.406 (p < 0.001) for the atlas plane line (weak). Though a linear correlation was identified, there were consistent intra-person differences between the measurements on the full spine versus sectional lateral cervical radiographic views, where the full-spine view consistently underestimated the magnitude of the variables. (4) Conclusion: Key sagittal cervical radiographic measurements on the full spine versus sectional lateral cervical radiographic views show striking intra-person differences. The findings of this study confirm that full spine versus sectional lateral cervical radiographic views provide different biomechanical magnitudes of cervical sagittal alignment, and caution should be exercised by health care providers as these are not interchangeable. We recommend the LC view for measurement of cervical sagittal alignment variables.

Capturing the cervical spine shape: Angular measurements versus geometric morphometric methods

The cervical spine manifests a wide shape variation. However, the traditional methods to evaluate the cervical spine curve were never tested against its actual shape. The study's main aim was to determine whether the shape classification of the cervical spine, based on traditional angular measurements, coincides with each other and with the shape captured by the 2D landmark-based geometric morphometric method. The study's second aim was to reveal the associations between the cervical spine shape and the demographic parameters, the head's position, and the spine's sagittal balance. CT scans of the cervical spine of 163 individuals were evaluated to achieve these goals. The shape was assessed by measuring the C2-C7 Cobb angle (CA), the C2-C7 posterior tangent angle (PTA), the curvedness of the arch, and by a 2D landmark-based geometric morphometric method. The position of the head and the sagittal balance of the spine were evaluated by measuring the foramen magnum-C2 Cobb angle (FMCA) and the T1 slope angle (T1SA), respectively. Based on the size of the angle measured, each individual was classified into one of the three cervical 'shape groups' (lordotic, straight, and kyphotic). We found that cervical lordosis was the dominant shape regardless of the measuring methods utilized (46.6%-54.6%), followed by straight neck (28.2%-30.1%), and kyphosis (15.3%-25.2%); however, about a third of the 163 individuals were classified into a different shape group using the CA and PTA methods. The cervical spine angle was sex-independent and age-dependent. The T1SA was significantly correlated with CA and PTA (r = 0.640 and r = 0.585, respectively; p < 0.001). In conclusion, the cervical spine shape evaluation is method-dependent and varies with age.

Unexpected postoperative atlantoaxial rotatory subluxation after excision of melanocytic nevi of the head and neck in older children: two case reports and literature review

Postoperative atlantoaxial rotatory subluxation (AARS) is a rare complication that develops almost exclusively in children following oropharyngeal and otologic surgeries, proposing that oropharyngeal inflammatory responses and excessive head rotation are responsible factors. However, there have been no reports of AARS after excision of a nevus on the head and neck. Here, we present two cases of AARS following limited head rotation during simple nevus excision. Patient 1, a 9-year-old girl, complained of neck pain and limited range of motion after excision of the nevus on the neck. After 2 months, computed tomography and magnetic resonance imaging finally revealed AARS with a ruptured transverse atlantal ligament. A month of halo traction was required for the treatment. Patient 2, an 11-year-old girl, presented with immediate pain and limited neck extension after tissue expander insertion under the upper chest and excision of the nevus on her left cheek. The diagnosis was promptly made using cervical spine radiography. A cervical collar was applied for 1 month. Both patients recovered without any complications after treatment. This report highlights the importance of suspicion for AARS after surgery regardless of surgical duration or amount of head rotation.

Pediatric Cervical Kyphosis: A Retrospective Multicenter Analysis and Literature Review

Introduction

This study aims to investigate cervical kyphosis in children, which has gained increasing attention in recent years due to its higher incidence and its association with tumor surgeries, and to shed light on the unique anatomical and biomechanical differences between pediatric and adult populations regarding cervical sagittal alignment. Additionally, it explores the diverse causes and management approaches, which often pose significant challenges. Furthermore, this study presents the management outcomes from three spine centers in the Middle East.

Methods

A retrospective analysis was conducted on patient records from 2009 to 2021 in three centers located in Saudi Arabia, Egypt, and Jordan. Demographic and clinical data were collected, imaging studies were reviewed, and various treatment modalities and their corresponding outcomes were documented and analyzed. Additionally, a literature review on pediatric cervical kyphosis and its management was performed.

Results

Seventeen patients were included in this study. The average age at presentation was 11.9 years. Among the participants, 14 underwent surgical treatment, 1 was treated with Minerva orthosis, and 2 were observed. The mean follow-up period was 32.4 months. In surgically treated patients, a statistically significant higher degree of correction was achieved when combining anterior and posterior surgeries compared to performing standalone anterior or posterior surgery (P-value = 0.014).

Conclusions

Although rare, pediatric cervical kyphosis is a significant condition within the spectrum of pediatric deformities and frequently occurs as a component of syndromes or as a result of iatrogenic factors. Neck pain and myelopathy are the most commonly observed symptoms. Thorough evaluation and complex surgical interventions are typically required for most cases.

Sagittal Alignment in the Degenerative Lumbar Spine: Surgical Planning

➤ Sagittal alignment of the spine has gained attention in the field of spinal deformity surgery for decades. However, emerging data support the importance of restoring segmental lumbar lordosis and lumbar spinal shape according to the pelvic morphology when surgically addressing degenerative lumbar pathologies such as degenerative disc disease and spondylolisthesis.➤ The distribution of caudal lordosis (L4-S1) and cranial lordosis (L1-L4) as a percentage of global lordosis varies by pelvic incidence (PI), with cephalad lordosis increasing its contribution to total lordosis as PI increases.➤ Spinal fusion may lead to iatrogenic deformity if performed without attention to lordosis magnitude and location in the lumbar spine.➤ A solid foundation of knowledge with regard to optimal spinal sagittal alignment is beneficial when performing lumbar spinal surgery, and thoughtful planning and execution of lumbar fusions with a focus on alignment may improve patient outcomes.

Don't Just Stand There. Rethinking the Ideal Body Posture for Otorhinolaryngologists

Surgeons have a high rate of work-related musculoskeletal injuries; an area that has received little attention. These injuries result in surgeons performing less efficiently, needing to take time off work, suffering higher rates of burnout, and may ultimately lead surgeons to retire earlier than planned. Otorhinolaryngologists are at particular risk for work-related musculoskeletal injuries. Beyond the clinician, sustaining such injuries can negatively impact patient safety. Ergonomic interventions have been used effectively to reduce work-related musculoskeletal injuries in other professions, yet not in surgery. With traditional teachings of ideal body postures to avoid injury and manual handling training being re-evaluated, it is important to explore evidence based interventions for reducing work-related musculoskeletal injuries in otorhinolaryngologists. New research encourages us to shift the focus away from the traditional one-size-fits-all approach to ergonomics and toward postural recommendations and education that promote a dynamic, individualized approach to avoiding sustained, static and awkward postures.

A Preliminary Diagnostic Model for Forward Head Posture among Adolescents Using Forward Neck Tilt Angle and Radiographic Sagittal Alignment Parameters

Despite numerous attempts to correct forward head posture (FHP), definitive evidence-based screening and diagnostic methods remain elusive. This study proposes a preliminary diagnostic methodology for FHP, utilizing a noninvasive body angle measurement system as a screening test for FHP and incorporating radiological parameters for sagittal alignment. We enrolled 145 adolescents for FHP screening. The forward neck tilt angle (FNTA), defined as the angle between the vertical line and the line connecting the participant's acromion and tragus, was measured using the POM-Checker (a noninvasive depth sensor-based body angle measurement system). A whole-spine standing lateral radiograph was obtained, and eight sagittal alignment parameters were measured. Statistical analyses of the association between the FNTA and eight sagittal alignment parameters were conducted. We used 70% of the participant data to establish a preliminary diagnostic model for FHP based on FNTA and each sagittal alignment parameter. The accuracy of the model was evaluated using the remaining 30% of the participant data. All radiological parameters of sagittal alignment showed weak statistical significance with respect to FNTA (best case: r = 0.16, p = 0.0500; cranial tilt). The proposed preliminary diagnostic model for FHP demonstrated 95.35% agreement. Notably, the model using FNTA without radiological parameters accurately identified (100%) participants who required radiographic scanning for FHP diagnosis. Owing to the weak statistical significance of the association between radiological parameters and external body angle, both factors must be considered for accurate FHP diagnosis. When a clear and severe angle variation is observed in an external body angle check, medical professionals should perform radiographic scanning for an accurate FHP diagnosis. In conclusion, FNTA assessment of FNTA through the proposed preliminary diagnostic model is a significant screening factor for selecting participants who must undergo radiographic scanning so that a diagnosis of FHP can be obtained.

Do key measurement parameters derived from specific cervical vertebral segments differ between lordotic and non-lordotic cervical spine alignments? A study of asymptomatic young adults

BACKGROUND

Measurement parameters derived from specific cervical vertebral segments (e.g., C2 slope) can provide clinicians with important information on cervical sagittal balance and guide pre- and post-surgical decision-making processes. It is unclear however, what constitutes typical values for these types of measurements in an asymptomatic population of young adults, whether values change depending upon the classification of the cervical spine's global alignment, and if any non-lordotic cervical subtypes display values that are comparable to those reported for pre-surgery patients.

METHODS

Neutral lateral cervical radiographs of 150 asymptomatic participants (18-30 years) were taken. Global cervical alignment was classified as lordotic or one of four non-lordotic subtypes using a multi-method subtyping protocol. Four key measurement parameters - the anterior translation of the head measure (ATHM), C0-C2 angle, C2 slope, and C7 slope - were derived from specific cervical segments. Independent samples t-tests were used to compare lordotic and non-lordotic groups.

RESULTS

There was considerable variation in the four key measurement parameters amongst this asymptomatic population of young adults. Thirty-four percent of the sample were classified as lordotic and 66% were classified as non-lordotic. There was a significant difference (p ≤ 0.0125) between lordotic and non-lordotic groups for the C0-C2 angle, C2 slope and C7 slope. There was no difference between groups for the ATHM (p ≥ 0.0125). Within the non-lordotic group, the global-kyphotic (GK) subtype had the largest mean C2 slope, largest mean C0-C2 angle, and smallest mean C7 slope.

CONCLUSIONS

Long term prospective investigations are required to determine whether possible biomarkers (alignment parameters/radiological measurements) for spinal degenerative changes can be identified so that early interventions can be put in place to try and reduce the impact of neck pain on society.

Analysis of sagittal spinal alignment at the adolescent age: for furniture design

Knowledge of the parameters of the human spine is essential in designing ergonomic furniture. The purpose of this study was to evaluate spinal alignment in adolescents of various ages. The lengths, curvatures, and concave-convex spacings of the spine were investigated in 268 participants aged 9-18 years. Ten ages were classified, and the rate of increase of parameters was calculated for each age and age group. The results showed that spinal parameters, except for cervical lordosis, increased with age. Adolescents were classified as 9-10, 11-12, 13-15, and 16-18 years old. A rapid increment of lengths and concave-convex spacings occurred at ages 13-15, while that of curvatures occurred at ages 16-18. Spinal parameters differed significantly among the age groups (p < 0.05). Concave-convex spacings reflected differences in the spine more clearly than the other parameters. This study suggests the necessity of designing spine-related furniture based on spinal parameters, thus providing adaptive support for the adolescent spine, particularly the lumbar spine. Practitioner summary: This study examined spinal lengths, curvatures, and concave-convex spacings in adolescents aged 9-8 years and then divided them into four age groups. Concave-convex spacings effectively reflected spinal differences between age groups, particularly the lumbar spine. These results can inform the ergonomic design of spine-related furniture.HIGHLIGHTSSpinal parameters increased progressively between 9 and 18 years. Regression analysis showed good linear correlations between TK, LL, SK, TS, and LS with age.Age classification of adolescents was Group I (9-10 years), Group II (11-12 years), Group III (13-15 years), and Group IV (16-18 years). The rapid increment of lengths and concave-convex spacings were in Group III while that of curvatures were in Group IV.Concave-convex spacings were vital parameters to evaluate the global balance of the spine.The lumbar spine is an essential segment for characterizing spinal alignment.

The Incidence, Changes and Treatments of Cervical Deformity After Infection and Inflammation

A healthy cervical spine with normal movement is the basis of many daily activities and is essential for maintaining a good quality of life. However, the alignment, fusion, and structure of the cervical spine can change for various reasons, leading to cervical deformity, mainly kyphosis. Approximately 5%‒20% of spinal infections in the cervical spine cause cervical deformity. The deformity can recover early; however, the disease's long-term existence or the continuous action of abnormal stress may lead to intervertebral fusion and abnormal osteophytes. Many gaps and controversies exist regarding infectious cervical deformities, including a lack of clear definitions and an acceptable classification system thereby requiring further research. Moreover, there is no consensus on the indications for postinfectious cervical deformity associated with <i>Mycobacterium tuberculosis</i>, <i>Staphylococcus aureus</i>, and Brucellosis. Therefore, we reviewed and discussed the incidence, clinical manifestations, changes, and treatment of infectious and inflammatory secondary cervical deformities from common to rare to provide a theoretical basis for clinical decision-making.

Analysis of Components of Upper Cervical Lordosis in Asymptomatic Lordotic and Kyphotic Subjects

BACKGROUND

Upper cervical lordosis (CL) can be divided into 2 components: C2 slope (C2S) and McGregor slope (MGS) or C0-1 and C1-2 angles. The aim of this study was to investigate the components of upper CL in asymptomatic kyphotic and lordotic subjects.

METHODS

CL, C0-2 Cobb angle, MGS, C2S, C1 Slope, C0-1 Cobb angle, C1-2 Cobb angle, T1 slope angular parameters, and the C2-7 sagittal vertical axis distance of 78 asymptomatic subjects were measured.

RESULTS

Sixty subjects had lordotic curvature and 18 had kyphotic curvature. There was a significant difference between the kyphotic and lordotic groups in all parameters, except for C0-1 Cobb angle and C2-7 sagittal vertical axis. In lordotic subjects, MGS and C2S accounted for 58% and 42% of the C0-2 angle, whereas in kyphotic subjects, 86% of C0-2 was accounted for by C2S. There was a strong negative correlation between C2S and MGS.

CONCLUSIONS

In asymptomatic subjects, as CL decreases, MGS decreases, C2S increases, and the C0-2 angle turns down on the horizontal plane to maintain the horizontal gaze. Turning down the C0-2 angle is more important than its value for maintaining horizontal gaze; thus, the slopes (MGS and C2S) can better represent the upper and lower cervical alignment than angle values can. The relationship between upper and lower cervical alignment should be evaluated in terms of slope angles rather than simple angles. The lack of significant difference between the C0-1 angles in the kyphotic and lordotic groups suggests that only the C1-2 angle is involved in the compensatory mechanism for the horizontal gaze.

Congenital Cervical Spinal Deformities

Malformations of the cervical spine are a challenge in pediatric orthopedic surgery since the treatment options are limited. These congenital anomalies are often syndrome-related and have multiple repercussions on the function and statics of the cervical spine in all three planes. They are related to developmental abnormalities during the somite segmentation that occurs during the third week of embryonic development. Successful somitogenesis requires proper functioning of a clock regulated by complex signaling pathways that guide the steps needed to form the future spine. There is no specific classification for vertebral malformations at the cervical level. To characterize the progressive nature of a malformation, one must use general classifications. In the specific case of Klippel-Feil syndrome, these malformations can affect several vertebral levels in a continuous or discontinuous manner, but also the vertebral body and vertebral arch in a variable way. Thus, establishing a reliable prognosis in the coronal and sagittal planes is a complex undertaking. While technical mastery of certain osteotomy procedures has led to advances in the surgical treatment of rigid deformities of the cervical spine, the indications are still very rare. Nevertheless, the procedure has become safer and more accurate because of technical aids such as surgical navigation, robotics and 3D printed models or patient-specific guides. Occipitocervical transitional anomalies have embryological specificities that can explain the bony malformations seen at this level. However, most are rare, and the main concern is identifying any instability that justifies surgical stabilization. The presence of a cervical spine anomaly should trigger the search for occipitocervical instability and vice-versa.

Sagittal balance of the cervical spine in children older than 4 years: what is the norm?

Objective. To search for normal parameters of the sagittal balance of the cervical spine in children, to analyze their dynamics in different periods of childhood, and to compare them with the norm given for the adult population.Material and Methods. To assess the parameters of the sagittal balance of the cervical spine, radiographs were selected that were initially evaluated by radiologists as a variant of the norm. The final sample consisted of 73 radiographs of 44 girls and 29 boys aged 4 to 17 years.Digital radiographs were used to evaluate the 10 most common parameters presented in publications: the angular values of Oc–C2, C2–C7, C7S, Th1S, TIA, NT, CeT, CrT, SCA, as well as the cSVA distance measured in mm. The measurements were carried out independently by 3 specialists working with pediatric patients: an orthopedic surgeon (experience up to 5 years), an orthopedic surgeon (experience more than 15 years), and a radiologist specializing in skeletal pathology (experience more than 5 years). The obtained results weresubjected to statistical processing.Results. Using multivariate analysis of variance, the presence of a statistically significant difference in age was revealed only for cSVA, gender differences were revealed for 6 out of 10 parameters. Most of the parameters showed good and satisfactory agreement between specialists.A very strong correlation was established between the parameters C7S and Th1S, which correlates with the adjacent position of the vertebrae.The C2–C7 and SCA parameters have a strong positive correlation with each other, the CeT parameter is strongly negatively correlated with both of them. The TIA has a strong negative correlation with SCA and a moderate positive correlation with NT, CeT, C7S, and Th1S. The cSVA and CrT values strongly correlate only with each other. Comparison of the obtained parameters of the sagittal balancein children with the data in scientific publications on the adult population revealed statistically significant differences in the values of 6 out of 10 of them.Conclusion. The age norms of the main parameters of the sagittal balance for children, and their gender differences were determined. Their difference from the normal parameters of the adult population was established, which requires that these features be taken into accountin clinical practice.

Severe dysphagia after a posterior cervical spine fusion at the C1–C3 level and its improvement after correction surgery for malalignment: a case report

Background

The development of dysphagia and trismus following posterior C1–C3 fusion is rare compared to occipitocervical fusion, and there are very few reports in the literature.

Case presentation

A 75-year-old Thai man who had an extradural tumor at the C1/C2 level developed severe dysphagia and trismus immediately after tumor resection and C1–C3 fusion. During the surgery for malalignment correction, the C1–C2 screws were re-aligned into an increased lordotic position. The symptoms resolved immediately post-surgery.

Conclusions

Short upper cervical fusion can produce trismus and dysphagia in a relatively flexed position. Preoperative planning should be individualized based on the patient’s resting neutral alignment to prevent complications.

Comparison of Spinopelvic Configuration and Roussouly Alignment Types Between Pediatric and Adult Populations

STUDY DESIGN

Retrospective cross-sectional study.

OBJECTIVE

The aim was to describe spinopelvic alignment types by pelvic incidence (PI) and age to compare the Roussouly classification between pediatric and adult populations.

SUMMARY OF BACKGROUND DATA

The Roussouly classification was validated for adults. Alignment types may vary during growth.

MATERIALS AND METHODS

Radiographs of 1706 non pathologic individuals (5-49 yr) were analyzed. Individuals ≤19 years were stratified by chronological age and skeletal maturity (triradiate cartilage, Risser), and compared with adults. Global and spinopelvic alignment parameters were assessed. Roussouly Types 1, 2, 3, 3A (anteverted pelvis), and 4 were determined. The distribution of parameters was analyzed by Bayesian inference. The relationship between PI and age by Roussouly type was modeled by linear regression.

RESULTS

The Sagittal Vertical Axis C7 decreased during growth and was significantly smaller in adults (20-34 yr) (Pr>0.99). Thoracic kyphosis and lumbar lordosis increased during growth and were larger in adults (Pr<0.025). Lordosis increased mainly in the cranial arch (Pr<0.025). PI and pelvic tilt increased during growth and were larger in adults (Pr<0.025). In children and adolescents, PI<45° represented the largest proportion, significantly larger compared with adults (Pr>0.99). Proportions of Roussouly Types 1 and 2 were similar throughout ages. Types 3 and 4 were rarer during the prepubertal period (Pr<0.025). The proportion of Type 3A was significantly higher in children and adolescents (Pr>0.99). Linear regression showed that Type 4 had the largest PI increase with age, with significantly higher curve slope compared with other types (Pr>0.9999). Types 3, 3A and 2 had similar slopes and lowest PI increase with age.

CONCLUSION

Global and spinopelvic alignment changed during childhood and adolescence, leading to different kyphosis and lordosis distribution compared with adults. Growth-related PI increase influenced Roussouly types with typical predominance of Type 3A in the pediatric population and larger PI increase in Type 4.

LEVEL OF EVIDENCE

Level III.

Young people's low back pain and awareness of postural habits: A cross-sectional study

BACKGROUND

Young people tend to spend most of their time in activities involving inappropriate positions, which can promote musculoskeletal alterations and disorders.

OBJECTIVE

To investigate the prevalence of low back pain (LBP) in young people and analyse its associations with daily postural habits.

METHODS

Cross-sectional and retrospective study evaluating 679 Brazilian young people (15 to 18 years old), using questionnaires about LBP and awareness of postural habits. The prevalence values were calculated for the present moment, the last three months and throughout life. The Mann-Whitney U test and the Chi-square test were applied.

RESULTS

The prevalence of LBP at the present moment was 27.2%, 57.7% over the last three months and 73.9% throughout life. Boys and girls presented significantly different values, a larger number of girls manifesting pain for the three moments. The associated postural habits were: turning the body, reduction of lumbar lordosis when seated, not placing the feet on the floor, crossing the legs when sitting in the classroom and at home, sitting or lying in an inappropriate position, and distributing the body asymmetrically on the legs when standing.

CONCLUSIONS

Young people from 15 to 18 years of age show a high prevalence of low back pain. Inadequate postural habits adopted during everyday activities are associated with this complaint. These findings could contribute to the implementation of prevention and rehabilitation strategies.

Sagittal alignment of the cervical spine: radiographic analysis of 111 asymptomatic adolescents, a retrospective observational study

Purpose

To describe the cervical spine morphology and explore its relationship to global sagittal alignment parameters in the asymptomatic adolescent population. 

Methods

A total of 111 adolescent subjects were included. Sagittal alignment parameters, including C7 Slope, C2-C7 Cobb, C2-7 plumb line (PL), C2-S1 Sagittal Vertical Axis (SVA), C7-S1 SVA, T5-12 Cobb, T10-L2 Cobb, L1-S1 Cobb, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS), were obtained from lateral radiographs. 

Results

Forty-four males and sixty-seven females with a mean age of 16.12 ± 2.40 years were included in this study. The mean values of C7 Slope, C2-7 Cobb and C2-7PL were 20.45 ± 8.88°, -7.72 ± 12.10°, and 13.53 ± 11.63 mm, respectively. C2-7 Cobb, C7 Slope showed significant differences between the male and female groups. Correlation analysis showed that C7 slope was significantly correlated with C2-7 Cobb (r = -0.544, P < 0.001), C2-S1 SVA (r = 0.335, P < 0.001), and C7-S1 SVA (r = 0.310, P = 0.001), but not lumbosacral parameters(L5-S1 Cobb, PI, PT, SS). Using a modified method of Toyama to describe the cervical spine morphology, there were 37 cases (33.3%) in the Lordotic group, and C7 slope, C2-7 Cobb and C2-7PL showed significant differences between groups. According to C2-C7 Cobb, there were 80 Lordotic cases (72.1%). C7 slope and C2-7PL were significantly different between the two groups.

Conclusion

The cervical spine morphology of asymptomatic adolescents varies widely, from lordotic to kyphotic. Combining different classification methods provides a better understanding of the morphology of the cervical spine. C7 slope is an important predictor of global sagittal balance and C2-7PL is a key parameter for restoring cervical lordosis, which should be considered pre-operatively and for conservative treatment. Cervical regional sagittal alignment parameters are not correlated with lumbosacral parameters, and C2-7 Cobb, C7 Slope showed significant differences between males and females.

Variation of cervical sagittal alignment parameters according to gender, pelvic incidence and age

PURPOSE

The aim was to describe radiographic cervical sagittal alignment variations according to age, gender and pelvic incidence (PI) and to investigate relationships with thoracic alignment.

METHODS

A total of 2599 individuals (5-93 years) without spinal deformity were studied. Cranial cervical parameters were: McGregor slope, occipita-C2 angle, McGregor-C2 lordosis and C1-C2 lordosis. Caudal cervical parameters were: C2-C7, cranial arch and caudal arch lordosis and C7- and T1-slope. A Bayesian inference compared parameter distributions. Correlations with spinopelvic and global alignment parameters were investigated.

RESULTS

Among cranial cervical parameters, variations of McGregor slope were non-significant. McGregor-C2 lordosis and C1-C2 lordosis were smaller in males and increased significantly during growth, whereas the occipito-C2 angle decreased (Pr > 0.95). The occipito-C2 angle was larger and McGregor-C2 lordosis was smaller in low PI (Pr > 0.95). Among caudal cervical parameters, C2-C7 lordosis and C7- and T1-slope were larger in males and increased after 50 years (Pr > 0.95). Lordosis changes were non-significant in the cranial arch, whereas values increased in the caudal arch after 35 years (Pr > 0.95). Caudal parameter differences were non-significant between PI groups. Strong correlations existed between C2-C7, caudal arch lordosis, C7-slope, T1-slope and thoracic kyphosis. The sagittal vertical axis C2 correlated with caudal arch lordosis and T1-slope (ρ > 0.5; Pr > 0.95).

CONCLUSION

Cervical alignment parameters vary according to age, gender and PI. In the cranial cervical spine, changes occur mainly during growth. In the caudal cervical spine, lordosis increases in the caudal arch, which is related to thoracic kyphosis increase with age. The caudal cervical arch acts as a compensatory segment by progressive extension, allowing horizontal gaze.

Effect of age and gender on anterior cervical plating

OBJECTIVE

To investigate the effect of age and gender on anterior cervical plating (ACP) in light of radiological findings.

METHODS

The degree of lordosis angle was calculated using the posterior tangent method both in early (one month) and late postoperative period (6-12 months) and the difference between pre- and post-operative values was accepted as the degree of lordosis correction. The results were compared between patients below and over 45 years and between males and females. Interbody height was measured as the distance between the upper-end plate of the superior vertebral body and the lower-end plate of the inferior vertebral body. Based on this distance, both segmental height loss (mm) and the degree of total height loss (%) were calculated and were compared between groups.

RESULTS

The mean degree of lordosis correction was higher in the ACDF-CP group than in the ACDF-CA group and was higher in women than men in the ACDF-CP group compared to the control group. Moreover, the mean degree of lordosis correction was higher in patients aged below 45 years compared to patients aged over 45 years. Similarly, segmental height loss was lower in the ACDF-CP group compared to the ACDF-CA group, in women compared to men, and in patients aged below 45 years compared to patients aged over 45 years.

CONCLUSIONS

The implementation of ACDF-CP provided more beneficial outcomes compared to ACDF-CA with regard to lordosis correction and graft height loss. Moreover, ACDF-CP provided more favorable effects in women than in men and in patients aged below 45 years than in patients aged over 45 years.

Sagittal wedging of intervertebral discs and vertebral bodies in the cervical spine and their associations with age, sex and cervical lordosis: A large-scale morphological study

Many recent studies have focused on the functional and clinical importance of cervical lordosis. However, there is little accurate knowledge of the anatomical parameters that constitute cervical lordosis (i.e., the sagittal wedging angles of intervertebral discs and vertebral bodies) and their associations with age and sex. Standing lateral cervical radiographs of 1020 subjects (424 males, 596 females) with a mean age of 36.6 ± 17.0 years (range 7-95 years) were evaluated retrospectively. Cervical lordosis, the sum of intervertebral disc wedging angles from C2/C3 to C6/C7 and the sum of vertebral body wedging angles from C3 to C7 were measured. The sum of intervertebral disc wedging and the sum of vertebral body wedging were 20.6° ± 14.7° and -12.8° ± 10.3°, respectively. The sum of intervertebral disc wedging increased significantly with age and was significantly greater in males than females, whereas there was no sex-related difference in the sum of vertebral body wedging. The sum of intervertebral disc wedging was negatively correlated with sum of vertebral body wedging. Wedging of discs contributed to C2-C7 cervical lordosis more significantly than wedging of vertebral bodies. There were moderate positive correlations between cervical lordosis and intervertebral disc wedging angles at C3/C4, C4/C5 and C5/C6; weak correlations were observed at C2/C3 and C6/C7. This study constitutes the largest currently available analysis comprehensively documenting the anatomical characteristics of sagittal wedging of intervertebral discs and vertebral bodies in the cervical spine. The findings could improve understanding of the internal architecture of cervical lordosis among clinicians.

Age-related Changes in T1 and C7 Slope and the Correlation Between Them in More Than 300 Asymptomatic Subjects

STUDY DESIGN

A cross-sectional analysis using T1 slope (T1S) and C7 slope (C7S) in asymptomatic individuals.

OBJECTIVE

The aim of this study was to identify normative values, ranges of motion (ROMs), age-related changes in T1S and C7S, and correlation between the two slopes.

SUMMARY OF BACKGROUND DATA

Few studies have reported age-related changes in the T1S and C7S angles. Additionally, studies investigating the effects of cervical position on these slopes are limited.

METHODS

A total of 388 asymptomatic subjects (162 males and 226 females) for whom T1S measurement was performed on radiographs were enrolled in the study. The T1S and C7S angles were measured using neutral radiography of the cervical spine. ROMs were assessed by measuring the difference in alignment in the neutral position, flexion, and extension.

RESULTS

The mean C7S and T1S angles were 19.6° (22.2° in males, 17.9° in females) and 24.0° (26.7° in men and 22.1° in women), respectively. The T1S angle was significantly greater than the C7S angle. Both the C7S and T1S angles significantly increased with age. The flexion ROM of C7S was higher than that of T1S, whereas no significant difference was detected between the extension ROMs of the two slopes. The flexion ROMs of the two slopes did not change, whereas the extension ROMs significantly increased with age. A significant positive correlation was observed between the C7S and T1S angles (r2 = 0.75).

CONCLUSION

The normative values and age-related changes in C7S and T1S were analyzed. Both the C7S and T1S angles increased with age. The C7S angle was strongly correlated with the T1S angle, suggesting that C7S can substitute T1S on radiographic images.Level of Evidence: 3.

Prospective surgical solutions in degenerative spine: spinal simulation for optimal choice of implant and targeted device development

Objectives

The most important goal of surgical treatment for spinal degeneration, in addition to eliminating the underlying pathology, is to preserve the biomechanically relevant structures. If degeneration destroys biomechanics, the single segment must either be surgically stabilized or functionally replaced by prosthetic restoration. This study examines how software-based presurgical simulation affects device selection and device development.

Methods

Based on videofluoroscopic motion recordings and pixel-precise processing of the segmental motion patterns, a software-based surrogate functional model was validated. It characterizes the individual movement of spinal segments relative to corresponding cervical or lumbar spine sections. The single segment-based motion of cervical or lumbar spine of individual patients can be simulated, if size-calibrated functional X-rays of the relevant spine section are available. The software plug-in “biokinemetric triangle” has been then integrated into this software to perform comparative segmental motion analyses before and after treatment in two cervical device studies: the correlation of implant-induced changes in the movement geometry and patient-related outcome was examined to investigate, whether this surrogate model could provide a guideline for implant selection and future implant development.

Results

For its validation in 253 randomly selected patients requiring single-level cervical (n=122) or lumbar (n=131) implant-supported restoration, the biokinemetric triangle provided significant pattern recognition in comparable investigations (p<0.05) and the software detected device-specific changes after implant-treatment (p<0.01). Subsequently, 104 patients, who underwent cervical discectomy, showed a correlation of the neck disability index with implant-specific changes in their segmental movement geometry: the preoperative simulation supported the best choice of surgical implants, since the best outcome resulted from restricting the extent of the movement of adjacent segments influenced by the technical mechanism of the respective device (p<0.05).

Conclusions

The implant restoration resulted in best outcome which modified intersegmental communication in a way that the segments adjacent to the implanted segment undergo less change in their own movement geometry. Based on our software-surrogate, individualized devices could be created that slow down further degeneration of adjacent segments by influencing the intersegmental communication of the motion segments.

The influence of smartphone use on spinal posture - A laboratory study

BACKGROUND

Smartphones have become increasingly more popular and complicated tasks can be performed with these devices. However, the increasing use is associated with shoulder and neck pain, as well as with psychological addiction.

RESEARCH QUESTION

Do different smartphone tasks lead to changes in spinal posture and pelvic position? Is there a relationship between smartphone addiction and changes in posture?

METHODS

A cross-sectional study including 50 participants was performed. Test subjects completed the Smartphone Addiction Scale and the SF-36 health questionnaire. Subjects spinal posture and pelvic position during different smartphone tasks were measured through a surface topography system. The different tasks were: standing in an upright position, simulating a phone call, texting with one or two hands during standing or while walking on a treadmill. Paired T-tests and ANOVA tests were performed to evaluate differences. The Kendall rank test was used to investigate the association between clinical scores and changes in spinal posture.

RESULTS

All smartphone tasks lead to a significant increase in thoracic kyphosis and trunk inclination during standing and while walking. A significant increased lumbar lordosis was also found. Texting with one or two hands correlated with increased surface rotation. No associations between smartphone addiction and changes of the spinal posture were reported.

SIGNIFICANCE

This represents the first surface topography study that investigated the influence of different smartphone tasks on the spinal posture and pelvic position during standing and while walking. With the results of this study we demonstrated that smartphone use leads to significant changes of sagittal and frontal spine parameters. Further research should focus on the evaluation of possible detrimental effects of long-term smartphone use on the spinal posture and on the development of preventive measures.

Radiography and photogrammetry-based methods of assessing cervical spine posture in the sagittal plane: A systematic review with meta-analysis

BACKGROUND

There are numerous radiography and photogrammetry-based methods of assessing the cervical spine posture in the sagittal plane. The choice of instrument should be based on scientific parameters such as validity and reliability, thus avoiding restrictions to the applicability of the instrument.

RESEARCH QUESTION

What radiography and photogrammetry-based methods used to assess the cervical spine posture in the sagittal plane are valid and/or reliable?

METHODS

Systematic searches were conducted following Meta-analysis of Observational Studies in Epidemiology guidelines. Methodological quality was assessed according to the Brink & Louw appraisal tool.

RESULTS

Twenty-one studies were included in the qualitative analysis. Twenty different methods of calculating cervical spine posture in the sagittal plane were found. Two studies included validation measures, 16 studies assessed inter-rater reliability, and 17 studies assessed intra-rater reliability. Fourteen studies were included for the quantitative analysis. The meta-analysis shows that the cervical arrow and cervical lordosis photogrammetry-based methods present very high intra-rater reliability. In radiography, the meta-analysis also showed that the Cobb method (inferior C2 - inferior C7), Cobb method (middle C1 - inferior C7), absolute rotation angle, and Gore angle (C2-C7) present very high inter-rater reliability, and the Cobb method (inferior C2 - inferior C7) and absolute rotation angle present very high intra-rater reliability.

SIGNIFICANCE

This systematic review presents an overview of the methods used to assess cervical spine posture and the respective information on validity and reliability. This panorama facilitates the choice of method when conducting radiography or photogrammetry-based assessment of the cervical spine in the sagittal plane. In addition, it shows the need for new studies that investigate the accuracy and precision of these methods for their possible use in larger studies.

Sagittal balance of the spine

Spinal balance can be defined as the trade-off between outside forces acting on the spine and the muscle response of the trunk, under sensorineural regulation, to maintain stable upright posture, both static and dynamic. Homo sapiens developed sagittal alignment along with bipedalism. The upright posture was an important step in human evolution, to master the environment, at the price of some instability in postural control in the trunk, and to maintain horizontal gaze. To make upright stance energetically economical and thus sustainable, reciprocal sagittal curvatures developed. Sagittal spinal organization is governed by strict rules under physiological conditions, enabling alignment between the center of mass and the lower limb joint centers. In children and adolescents, morphologic changes related to skeletal growth and postural control centers maturation alter spinal alignment and hence spinal balance, with increases in pelvic incidence, sacral slope and consequently lumbar lordosis and thoracic kyphosis. Global cervical lordosis remains stable, at the cost of an increase of the inferior cervical lordosis angle in correlation with T1 inclination or T1 slope. In pathology, spinal alignment may induce certain spinal pathologies such as growth-related spinal dystrophy or spondylolisthesis. It can also be altered by spinal deformity such as scoliosis, a regional disorder inducing adjacent compensatory mechanisms. The management of spinal pathologies is indissociable from understanding and maintaining or restoring individual sagittal alignment so as to ensure physiological distribution of stresses and limit onset of complications or decompensation in adulthood.

Cervical Sagittal Alignment: Literature Review and Future Directions

Cervical alignment as a concept has come to the forefront for spine deformity research in the last decade. Studies on cervical sagittal alignment started from normative data, and expanded into correlation with global sagittal balance, prognosis of various conditions, outcomes of surgery, definition and classification of cervical deformity, and prediction of targets for ideal cervical reconstruction. Despite the recent robust research efforts, the definition of normal cervical sagittal alignment and cervical spine deformity continues to elude us. Further, many studies continue to view cervical alignment as a continuation of thoracolumbar deformity and do not take into account biomechanical features unique to the cervical spine that may influence cervical alignment, such as the importance of musculature connecting cranium-cervical-thoracic spine and upper extremities. In this article, we aim to summarize the relevant literature on cervical sagittal alignment, discuss key results, and list potential future direction for research using the '5W1H' framework; "WHO" are related?, "WHY" important?, "WHAT" to evaluate and "WHAT" is normal?, "HOW" to evaluate?, "WHEN" to apply sagittal balance?, and "WHERE" to go in the future?

Changes in the Position of the Junctional Vertebrae After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: Implication in Risk Assessment of Proximal Junctional Kyphosis Development

BACKGROUND

The development of proximal junctional kyphosis (PJK) after posterior spinal fusion in adolescent idiopathic scoliosis is a major problem. Changes in the global sagittal parameters as they relate to PJK have been reported after surgery, however, the relationships between the changes in the upper-instrumented vertebra (UIV) during and after surgery as they relate to development of PJK have not been quantified. We hypothesize that the compensatory changes in the unfused segments of the spine over time are correlated with the surgically induced changes in the UIV position.

METHODS

Sixty adolescent idiopathic scoliosis patients (with at least 1-year follow-up) who underwent posterior spinal surgery were included retrospectively. Global spinal parameters were calculated using 3-dimensional models of the spine, additional parameters [proximal junctional kyphosis angle (PJKA), cervical lordosis angle] were measured manually before surgery and at 3 postoperative follow-ups. The 3-dimensional position of the vertebral body centroids was calculated for T1, UIV, and lower-instrumented vertebra at all timepoints. The sagittal position of T1, UIV, and lower-instrumented vertebra were correlated to the cervical lordosis, PJKA, lumbar lordosis, and pelvic tilt.

RESULTS

The position of T1 and UIV were significantly more anterior at first erect for patients who developed PJK. The posterior shift of UIV at the most recent follow-up as compared with the preoperative position was significant in both the PJK and non-PJK cohort. A larger anterior shift in UIV at first erect correlated with a larger T1 and UIV posterior shift at the most recent follow-up. At the most recent follow-up, a more posterior position of the UIV correlated with a larger angle of PJKA (P<0.05).

CONCLUSION

Both a larger anterior shift of UIV between preoperative and first erect and a more posterior position of UIV at the most recent follow-up was correlated with a higher PJKA. A larger anterior shift in the position of the UIV after surgery was associated with a higher posterior shift of UIV at the last follow-up. The surgically induced changes in the UIV are an important parameter associated with the development of PJK.

LEVEL OF EVIDENCE

Level IV.

Analysis of the Effect of Surgical Treatment for the Patients with Hirayama Disease from the Perspective of Cervical Spine Sagittal Alignment

OBJECTIVE

This study was carried out to analyze the surgical effect of cervical spine sagittal alignment for patients with Hirayama disease (HD).

METHODS

Forty-four subjects were retrospectively analyzed for the parameters of cervical spine sagittal alignment. The case group consisted of 23 patients with HD, whereas the control group consisted of 21 healthy adolescent subjects. Pre- and postoperative cervical spine sagittal parameters of the patients with HD were collected; the cervical sagittal parameters of the healthy adolescent subjects were also collected. Sagittal alignment parameters were compared between the patients with HD and the healthy adolescent subjects, and between the pre- and postoperative parameters for the patients with HD.

RESULTS

Forty-four subjects completed the follow-up, with the average follow-up period being 18.0 months. No significant differences were detected between the HD and control groups for clinical parameters (P > 0.05). The preoperative HD group had smaller values compared with the control group in the sagittal parameters of C2-7 cervical lordosis (CL) angle, T1 slope, thoracic inlet angle (TIA), and cervical tilt angle (P < 0.05). For the patients with HD, the preoperative values were smaller compared with the postoperative HD values for the parameters of C2-7 CL angle, T1 slope, and cervical tilt angle (P < 0.05). We found no significant differences between the postoperative patients with HD and the healthy subjects, including C2-7 CL angle, C2-7 sagittal vertical axis, T1 slope, TIA, neck tilt angle, cervical tilt angle, and cranial tilt angle (P > 0.05).

CONCLUSIONS

Patients with HD have sagittal imbalance of the cervical spine compared with age-matched healthy adolescent subjects, and surgical treatment could correct the sagittal imbalance.

Evaluating Cervical Sagittal Alignment in Cervical Myelopathy: Are Sitting Cervical Radiographs and Standing Whole-Spine Radiographs Equally Useful?

STUDY DESIGN

Retrospective review of medical charts and radiographic data.

OBJECTIVES

We aimed to clarify the differences in cervical alignment findings between sitting cervical lateral radiographs and standing whole-spine lateral radiographs with clavicle positioning in cervical spondylotic myelopathy (CSM) patients.

METHODS

We retrospectively evaluated the radiographs of 50 consecutive patients who underwent cervical surgery for CSM in our hospital. Cervical sagittal alignment was evaluated based on the C0-2 angles and C2-7 Gore and Cobb angles. Head position was evaluated in terms of the center of gravity of the head to C7 (CGH-C7) angle and the McGregor angle (ie, the angle between the McGregor line and a horizontal line). The T1-slope was also evaluated.

RESULTS

The mean values of the CGH-C7 angle and T1-slope were significantly lower, while the mean value of the McGregor angle was significantly higher on whole-spine lateral radiographs with clavicle positioning than on sitting cervical lateral radiographs. The mean values of the C0-2 and C2-7 angles did not differ significantly between the 2 radiographic positioning approaches.

CONCLUSIONS

Using whole-spine lateral radiographs with clavicle positioning may result in a significantly lower T1-slope and a posterior tilt of the head. In the absence of a compensatory change in cervical alignment, clavicle positioning may force patients to adopt an upward gazing position of the head. These compensatory mechanisms should be considered while evaluating cervical alignment on whole-spine lateral radiographs with clavicle positioning. Surgical planning should take into account the effect of posture on the radiographic appearance of cervical alignment.

CORRELATION BETWEEN CERVICAL MORPHOLOGY, PAIN, FUNCTIONALITY, AND ROM IN INDIVIDUALS WITH CERVICALGIA

ABSTRACT Objective: To verify if there is a correlation between the morphology of the cervical spine curvature, pain intensity, functional disability, and range of motion in individuals with cervicalgia. Methods: Thirty-nine individuals were evaluated using x-rays in the right sagittal plane (Cobb C1-C7 two-line method), visual analogue scale, Neck Disability Index questionnaire, and fleximeter. Descriptive statistical analysis (percentage, mean and standard deviation) and inferential (independent t-test and Pearson product-moment correlation coefficient, α=0.05) were performed. Results: There were significant correlations, ranging from moderate to high, between functional capacity and pain intensity (r=0.637, p<0.001), and total range of motion (r=-0.568, p<0.001), and extension (r=-0.610, p<0.001), and between pain intensity and range of motion (r=-0.422, p=0.007). Regarding the morphology of the cervical spine curvature, none of the variables showed a significant correlation. Conclusions: Cervical morphology, more specifically related to the curvature in the sagittal plane, does not seem to interfere alone with pain, functionality, and range of motion. In contrast, it is possible to affirm that higher levels of pain generate a smaller range of cervical movement, especially of extension, which, in turn, results in greater functional losses in individuals with neck pain. Level of Evidence II; Prognostic Studies - Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

The content and construct validity of the modified patient specific functional scale (PSFS 2.0) in individuals with neck pain

Study design: Clinical measurement study.Background: The Patient Specific Functional Scale (PSFS) is a commonly used outcome measure, however answering options differ and content validity has yet to be assessed.Objective: To assess the content validity of the PSFS in patients with neck pain presenting to a physical therapist. And secondly, to assess the construct validity of the PSFS using the preferred version identified in the content validity study.Methods: The target population consisted of patients with neck pain presenting to physical therapy. First, content validity was assessed through semi structured interviews and content thematic analysis. Second, construct validity was assessed on the PSFS 2.0 by examining its correlation with the Neck Disability Index (NDI).Results: Eleven patients were interviewed. Patients indicated the concept of 'activity limitations' is very important to them. The PSFS is considered to be relevant and easy to understand. Patients had an explicit preference for the PSFS 2.0 version (using a different answering option and example list) and indicated they preferred to answer the PSFS 2.0 together with a clinician. One hundred patients participated in the construct validity study on the PSFS 2.0. The median PSFS 2.0 score was 4.5 and the correlation with the NDI was substantial (0.54).Conclusion: The results of this study indicate that in individuals with neck pain, the PSFS is appropriate however; PSFS 2.0 is the preferred version. The PSFS 2.0 is considered to be valid in terms of content validity and construct validity for patients with neck pain.

Characteristics of Cervical Sagittal Alignment at Different C0-C2 Correcting Angles in Fusion Treatment of Atlantoaxial Dislocations

OBJECTIVE

To explore the appropriate range of C0-C2 correction angles by analyzing cervical sagittal alignment parameters and evaluating clinical outcomes.

METHODS

The preoperative and postoperative radiographs, visual analogue scale, Japanese Orthopedic Association score, and neck disability index of 65 atlantoaxial dislocation patients were retrospectively collected. The C0-C2 angle, C2-C7 angle, and cervical sagittal vertical axis (cSVA) were measured from the radiographs, and an assessment of cervical degenerative disc disease was made. According to the 2-year postoperative C0-C2 angles, all patients were categorized into a <10° subgroup, 10°-20° subgroup, and >20° subgroups.

RESULTS

The postoperative C2-C7 angles and cSVA of the 10°-20° subgroup were significantly different from those of the <10° subgroup. The Japanese Orthopedic Association score of the 10°-20° subgroup was significantly different from those of the <10° and >20° subgroups. All patients (26/26) in the 10°-20° subgroup exhibited a cSVA 0-40 mm, 25% of patients (6/24) in the >20° subgroup exhibited a cSVA >40 mm, and 40% of patients (6/15) in the <10° subgroup showed a cSVA <0 mm. The postoperative incidence of cervical degenerative disc disease did not increase in the 10°-20° subgroup.

CONCLUSIONS

Atlantoaxial dislocation patients with different C0-C2 postoperative angles had different cervical sagittal alignments and clinical outcomes. In our study, the patients within the C0-C2 10°-20° subgroup exhibited superior clinical outcomes and cervical sagittal alignment.

New sagittal classification of AIS: validation by 3D characterization

INTRODUCTION AND AIM

In order to improve surgical planning of sagittal correction in AIS, we proposed a new sagittal classification-Abelin-Genevois et al. Eur Spine J (27(9):2192-2202, 2018. https://doi.org/10.1007/s00586-018-5613-1 ). The main criticism is related to the fact that 2D lateral view results from the projection of the 3D deformity. The aim of this study is to show that the new sagittal classification system is a reliable system to describe the different sagittal scenarios that AIS could create both in 2D and 3D.

METHODS

We performed retrospective radiograph analysis of prospectively collected data from 93 consecutive AIS patients who underwent an examination of the whole spine using the EOS^® imaging system. 2D (Keops^®) and 3D analyses (sterEOS^®) provided frontal and sagittal spinal and spinopelvic parameters. In addition, 3D analysis provided apical vertebra rotation (AVR).

RESULTS

Comparing 2D and 3D measurements for the general cohort, excellent correlation can be found for all parameters, but only fairly good for T10L2 and L1S1 angles. The highest variability was observed for T10L2, differences between 2D and 3D measurements being greater when the Cobb angle increased. AVR did not influence concordance between 2D and 3D measurements. Eighty-two percent were similarly classified in 2D and 3D according to the new classification. Misclassified patients were all AIS sagittal type 3 in 3D analysis, thoracolumbar junction (TLJ) lordosis being underestimated on 2D view.

DISCUSSION

In conclusion, for the majority of cases (82%), 2D analysis may provide enough information for decision making when using a semi-automated 2D measurement system. However, in severe cases, especially when Cobb angle exceeds 55°, 3D analysis should be used to get a more accurate view on the thoracolumbar junction behavior. These slides can be retrieved under Electronic Supplementary Material.

Influence of the Occipital Orientation on Cervical Sagittal Alignment: A Prospective Radiographic Study on 335 Normal Subjects

Cervical sagittal alignment is considered to have a special role in the pathogenesis and evaluation of cervical diseases. Previous studies have demonstrated that cervical sagittal alignment is correlated with thoracolumbar and pelvic alignments. As the direct anatomical structures connect to the cervical region, however, no parameters in the occiput have been reported to be intimately related to the alignment of the cervical spine. A retrospective radiographic study of 335 individuals (182 males and 153 females) between 18 and 60 years of age was performed between January 2007 and January 2016. The occipital incidence (OI), occipital slope (OS), occipital tilt (OT), C0-C2 angle, C2-C7 angle, C0-C7 angle, T1 slope and thoracic kyphosis were measured in every individual. The mean values of the occipital parameters of the cohort were 34.6° ± 3.1° for OI, 23.4° ± 7.4° for OS, and 11.8° ± 3.3° for OT. OI was constant throughout three age groups. No significant differences were noted between males and females. In addition, strong correlations were found between the occipital parameters and cervical parameters. The occipital orientation was an important factor that influenced the cervical sagittal alignment.

Prevalence and Factors Affecting Cervical Deformity in Adolescent Idiopathic Scoliosis Patients: A Single-Center Retrospective Radiological Study

Background

It has been reported that adult spinal deformity patients have a high prevalence of cervical kyphosis (CK) and cervical positive sagittal malalignment (CPSM). However, the prevalence and possible factors affecting CK and CPSM in patients with adolescent idiopathic scoliosis (AIS) are less clear.

Methods

We retrospectively analyzed a consecutive series of AIS patients from a single center. Radiographic measurements included the Cobb angle, C2-C7 sagittal vertical axis (C2-C7SVA), and C2-C7 lordosis. Cervical deformity was defined as loss of lordotic or neutral cervical angle (CK) or C2-C7SVA more than 4 cm (CPSM). Patients were stratified by the degree of thoracic kyphosis and coronal thoracic curve.

Results

A total of 99 patients were included in this study. The patients' mean age was 14 years (range, 10-18 years). Mean cervical lordosis and C2-C7SVA were 1.5° and 30.4 mm, respectively. The CK and CPSM prevalence were 49% and 16%, respectively, and prevalence of CK and/or CPSM was 59%. CK was present in 32% of the patients who had >20° thoracic kyphosis, and it was present in 75% of the patients who had ≤20° thoracic kyphosis (P = .003). No association between CPSM and thoracic kyphosis was found. The patients who had >20° coronal thoracic curve had higher CK prevalence (64% versus 37%, P = .05), but no CPSM association was found.

Conclusions

Cervical deformity is highly prevalent in AIS patients. There is a significant correlation between the loss of thoracic kyphosis and the development of CK but not the development of CPSM. High coronal thoracic curve is associated with CK prevalence, but it is not associated with CPSM prevalence.

Sagittal classification in adolescent idiopathic scoliosis: original description and therapeutic implications

INTRODUCTION

Surgical treatment of AIS aims to correct the coronal and sagittal alignment of the spine. The global alignment of the spine may be normalized through reciprocal changes between the fused spine and adjacent segments. We propose a new classification system describing the specific sagittal patterns induced by AIS to define reproducible guidelines for the surgical strategy.

METHODS

We analyzed 100 consecutive AIS patients aged between 12 and 18 years candidate for spinal fusion. The following parameters were measured and compared for each pattern: spino-pelvic parameters, magnitude and length of the lumbar sagittal angle, magnitude and length of the thoracic sagittal angles (T1T12 and T4T12 angles, TKmax), T10 L2 angle, C7 slope and C2C7 angle.

RESULTS

Three parameters strongly differentiated the four patterns: thoracic sagittal angles (T1T12 and T4T12 angles, TKmax), T10 L2 angle and C7 slope. Less than half of the patients (44%) had a normal sagittal shape. Within, Type 2 characterized by thoracic hypokyphosis, Type 2a (thoracic hypokyphosis) were mostly Lenke type 1 or 2 curves, and type 2b (thoracic hypokyphosis with TL kyphosis) occurred specifically in double major or TL/L curves. Type 3 were two-curve sagittal shape with cervicothoracic kyphosis and TL lordosis (9%), mainly in Lenke 1 curves.

DISCUSSION

This new classification summarizes all the pathological scenarios of the sagittal alignment of AIS into four patterns. A specific surgical planning can be extrapolated for each pattern. In type 1, the objective is to preserve the sagittal shape. In type 2, the objective is to restore thoracic kyphosis. In type 2b, TL junction should be straightened. In type 3, the objective is to reshape the lower arc of thoracic sagittal angle and straighten the TL junction. These slides can be retrieved under Electronic Supplementary Material.

Cervical Facet Orientation Varies with Age in Children: An MRI Study

BACKGROUND

Within the spine, mobility and stability are principles that drive anatomic morphology. Based on radiographic measurements, the orientation of cervical facet joints has been proven to change throughout child growth. However, because of the mainly cartilaginous composition of the vertebrae in the young child, the lack of osseous landmarks makes radiograph-based measurements unreliable. The aims of our study were to evaluate the change in the sagittal orientation of the cervical facet joints with age based on magnetic resonance imaging (MRI) of asymptomatic children and to compare it to the changes in vertebral body dimensions.

METHODS

Sagittal images passing through the center of the facet joint or through the center of the vertebral body were used to assess facet orientation at every cervical level. Anteroposterior facet orientation was defined as the angle between the superior facet and a line perpendicular to the posterior wall of the vertebral body. Vertical was defined as parallel to the posterior wall; horizontal was defined as perpendicular to the posterior wall. Vertebral body height and anteroposterior diameter were measured as well.

RESULTS

MRI data of the normal cervical spine of 90 children who were 2 months to 18 years of age, obtained for neurologic evaluation, were used for this study. For each level from C3 to C7, there was a positive correlation between facet orientation and age (R = 0.498, p < 0.001). The facet joints were the most vertical at C3 (43.9°) and C7 (49.6°), whereas C5 had the most horizontal facets (39.4°). The greatest rate of change in facet orientation was observed between 6 and 9 years of age.

CONCLUSIONS

Our results demonstrate that facets become more vertical as a function of age. However, other parameters than age must be considered to explain the variation of facet orientation. At C3 and C7, the facet orientation was more vertical, which may increase stability. In between, C5 facets were shallower, which may increase mobility and flexion-extension range of motion.

Principal Radiographic Characteristics for Cervical Spinal Deformity: A Health-related Quality-of-life Analysis

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study was to propose radiographic characteristics of patients with cervical disability and to investigate the relevant parameters when assessing cervical alignment.

SUMMARY OF BACKGROUND DATA

Although cervical kyphosis is traditionally recognized as presentation of cervical deformity, an increasing number of studies demonstrated that cervical kyphosis may not equal cervical deformity. Therefore, several other differentiating criteria for cervical deformity should be investigated and supported with quality of life scores.

METHODS

A database of full-body radiographs was retrospectively reviewed. Patients without previous cervical surgery, with a well-aligned thoracolumbar profile (defined as T1 pelvis angle <15°), and with an available Neck Disability Index (NDI) score were reviewed in this study. Subjects were stratified into an asymptomatic (64 subjects with NDI ≤15, Visual Analogue Scale [VAS] neck ≤3, and VAS arm ≤3) and a symptomatic group (107 subjects with NDI >15, VAS neck >3, or VAS arm >3). Independent t tests were performed to investigate differences between two groups. Logistic regressions and principal component analyses were then performed.

RESULTS

NDI averaged 5.43 in asymptomatic group, significantly smaller than symptomatic group (5.43 vs. 41.25). t Test revealed that C2-C7 sagittal vertical axis (SVA), McGregor slope, and the slope of line of sight (SLS) were significantly different while C2-C7 angle (cervical curvature, CC) did not show statistical difference (P = 0.09). Logistic regressions were performed using the significantly different parameters as well as CC. Results identified C2-C7 SVA and SLS as independent risk factors for low health-related quality of life. The principal component analysis leads to a new factor (0.55 × C2C7SVA + 0.34 × COC2 + 0.77 × CC) with strong correlations with NDI, VAS, and EQ5D measurements.

CONCLUSION

The traditional concept of cervical kyphosis should not be regarded as a standalone criterion of cervical deformity. The most clinically relevant components of cervical analysis are the C2-C7 SVA, C0C2 angle, and C2C7 angle. In addition, the three components should be assessed together in harmony and not individually.

LEVEL OF EVIDENCE

4.

Cervical lordosis: the effect of age and gender

BACKGROUND CONTEXT

Cervical lordosis is of great importance to posture and function. Neck pain and disability is often associated with cervical lordosis malalignment. Surgical procedures involving cervical lordosis stabilization or restoration must take into account age and gender differences in cervical lordosis architecture to avoid further complications.

PURPOSE

Therefore, the purpose of the present study was to evaluate differences in cervical lordosis between males and females from childhood to adulthood.

STUDY DESIGN

This is a retrospective descriptive study.

PATIENT SAMPLE

A total of 197 lateral cervical radiographs of patients aged 6-50 years were examined. These were divided into two age groups: the younger group (76 children aged 6-19; 48 boys and 28 girls) and the adult group (121 adults aged 20-50; 61 males and 60 females). The retrospective review of the radiographs was approved by the institutional review board.

METHODS

On each radiograph, six lordosis angles were measured including total cervical lordosis (FM-C7), upper (FM-C3; C1-C3) and lower (C3-C7) cervical lordosis, C1-C7 lordosis, and the angle between foramen magnum and the atlas (FM-C1). Wedging angles of each vertebral body (C3-C7) and intervertebral discs (C2-C3 to C6-C7) were also measured. Vertebral body wedging and intervertebral disc wedging were defined as the sum of the individual body or disc wedging of C3 to C7, respectively. Each cervical radiograph was classified according to four postural categories: A-lordotic, B-straight, C-double curve, and D-kyphotic.

RESULTS

The total cervical lordosis of males and females was similar. Males had smaller upper cervical lordosis (FM-C3) and higher lower cervical lordosis (C3-C7) than females. The sum of vertebral body wedging of males and females is kyphotic (anterior height smaller than posterior height). Males had more lordotic intervertebral discs than females. Half of the adults (51%) had lordotic cervical spine, 41% had straight spine, and less than 10% had double curve or kyphotic spine. Children had similar total cervical lordosis (FM-C7) to adults. The sum of vertebral body wedging for children was more kyphotic-by 7°-than that of adults, whereas the sum of intervertebral disc wedging in children was more lordotic-by11°-than that of adults. Seventy-one percent of the children had lordotic cervical spine, 23% had straight spine, and less than 6% had double curve spine. Gender differences are already apparent in children as girls had higher upper cervical lordosis (FM-C3; C1-C3) than boys do.

CONCLUSIONS

Although the total cervical lordosis (FM-C7) did not change between age groups, and between males and females, the internal architecture of the cervical lordosis changed significantly. Practitioners before neck stabilization procedures or correction and restoration should therefore take into account the gender and age differences in cervical lordosis.

The efficacy of sagittal cervical spine subtyping: Investigating radiological classification methods within 150 asymptomatic participants

Aims:

The aim of this study is to (1) compare and contrast cervical subtype classification methods within an asymptomatic population, and (2) identify inter-methodological consistencies and describe examples of inconsistencies that have the potential to affect subtype classification and clinical decision-making.

Methods:

A total of 150 asymptomatic 18–30-year-old participants met the strict inclusion criteria. An erect neutral lateral radiograph was obtained using standard procedures. The Centroid, modified Takeshima/Herbst methods and the relative rotation angles in cases of nonagreement were used to determine subtype classifications. Cohen's kappa coefficient (κ) was used to assess the level of agreement between the two methods.

Results:

Nonlordotic classifications represented 66% of the cohort. Subtype classification identified the cohort as, lordosis (51), straight (37), global kyphosis (30), sigmoidal (13), and reverse sigmoidal (RS) (19). Cohen's kappa coefficient indicated that there was only a moderate level of agreement between methods (κ = 0.531). Methodological agreement tended to be higher within the lordotic and global kyphotic subtypes whereas, straight, sigmoidal, and RS subtypes demonstrated less agreement.

Conclusion:

This is the first study of its type to compare and contrast cervical classification methods. Subtypes displaying predominantly extended or flexed segments demonstrated higher levels of agreement. Our findings highlight the need for establishing a standardized multi-method approach to classify sagittal cervical subtypes.

Pediatric occipitocervical fusion: long-term radiographic changes in curvature, growth, and alignment

OBJECTIVE The authors assessed the rate of vertebral growth, curvature, and alignment for multilevel constructs in the cervical spine after occipitocervical fixation (OCF) in pediatric patients and compared these results with those in published reports of growth in normal children. METHODS The authors assessed cervical spine radiographs and CT images of 18 patients who underwent occipitocervical arthrodesis. Measurements were made using postoperative and follow-up images available for 16 patients to determine cervical alignment (cervical spine alignment [CSA], C1-7 sagittal vertical axis [SVA], and C2-7 SVA) and curvature (cervical spine curvature [CSC] and C2-7 lordosis angle). Seventeen patients had postoperative and follow-up images available with which to measure vertebral body height (VBH), vertebral body width (VBW), and vertical growth percentage (VG%-that is, percentage change from postoperative to follow-up). Results for cervical spine growth were compared with normal parameters of 456 patients previously reported on in 2 studies. RESULTS Ten patients were girls and 8 were boys; their mean age was 6.7 ± 3.2 years. Constructs spanned occiput (Oc)-C2 (n = 2), Oc-C3 (n = 7), and Oc-C4 (n = 9). The mean duration of follow-up was 44.4 months (range 24-101 months). Comparison of postoperative to follow-up measures showed that the mean CSA increased by 1.8 ± 2.9 mm (p < 0.01); the mean C2-7 SVA and C1-7 SVA increased by 2.3 mm and 2.7 mm, respectively (p = 0.3); the mean CSC changed by -8.7° (p < 0.01) and the mean C2-7 lordosis angle changed by 2.6° (p = 0.5); and the cumulative mean VG% of the instrumented levels (C2-4) provided 51.5% of the total cervical growth (C2-7). The annual vertical growth rate was 4.4 mm/year. The VBW growth from C2-4 ranged from 13.9% to 16.6% (p < 0.001). The VBW of C-2 in instrumented patients appeared to be of a smaller diameter than that of normal patients, especially among those aged 5 to < 10 years and 10-15 years, with an increased diameter at the immediately inferior vertebral bodies compensating for the decreased width. No cervical deformation, malalignment, or detrimental clinical status was evident in any patient. CONCLUSIONS The craniovertebral junction and the upper cervical spine continue to present normal growth, curvature, and alignment parameters in children with OCF constructs spanning a distance as long as Oc-C4.

Sagittal spino-pelvic adjustment in severe Lenke 1 hypokyphotic adolescent idiopathic scoliosis patients

PURPOSE

The human standing position requires permanent reciprocal spino-pelvic adjustments to obtain a dynamic and economic posture. This study focuses on a hypokyphotic Lenke 1 adolescent idiopathic scoliosis (AIS) patients cohort and points out their particular lumbo-pelvic adaptive mechanisms to maintain a neutral sagittal balance.

METHODS

Preoperative retrospective analysis of prospectively collected data on a monocentric cohort of 455 AIS patients planned for corrective surgery. Radiological low-dose system coupled with a validated clinical routine software allowed to obtain data from eighty-four hypokyphotic [thoracic kyphosis (TK) <20°] Lenke 1 patients and were separately analyzed. Bilateral Student and one-way ANOVAs were conducted for statistical analysis.

RESULTS

Mean Cobb angle was 46.3° (±7.2), TK was 11° (±7.1), sagittal vertical axis (SVA) was -10.1 mm (±30.9), pelvic incidence (PI) was 55.7° (±12.9). Fifty percents of patients were posteriorly imbalanced. Among them, patients with a low PI used an anteversion of their pelvis [indicated by a high pelvic tilt (PT) angle] but were not able to increase their lumbar lordosis (LL) to minimize the posterior spinal shift.

CONCLUSIONS

Hypokyphotic Lenke 1 AIS patients use lumbo-pelvic compensatory mechanisms to maintain their global balance with a poor effectiveness. Subjects with a low PI have a restricted range of LL adaptation. Attention should be paid during surgical planning not to overcorrect lordosis in the instrumented levels in case of non-selective fusion, that may induce posterior shift of the fusion mass and expose to junctional syndromes and poor functional outcomes in this particular patients.