Cervical vertebral maturation (CVM) stage as a supplementary indicator for the assessment of peak height velocity (PHV) in adolescent idiopathic scoliosis (AIS)

A comparative analysis of axial and appendicular skeletal maturity staging systems through assessment of longitudinal growth and curve modulation after VBT surgery

PURPOSE

Appendicular skeleton markers are commonly used for maturity assessment for Adolescent Idiopathic Scoliosis (AIS) patients. Traditionally, Risser has been a standard skeletal maturity assessment method. More recently, Sanders classification (SSMS), as a more comprehensive system, became popular, especially in decision-making for Vertebral Body Tethering (VBT). Thumb-Ossification Composite Index (TOCI), using ossification of thumb epiphyses, has been claimed to more accurately stage patients around their peak height velocity. However, growth peaks may occur separately at lower limbs and trunk. Hence, Cervical Vertebral Maturity (CVM), using cervical spine morphology, possesses a potential to better estimate spinal growth as it uses axial skeleton markers instead of appendicular skeleton markers. The aim of the study was to compare various axial and appendicular skeletal maturity assessment methods for longitudinal growth and curve modulation after VBT.

METHODS

A retrospective analysis of prospectively collected data was conducted. Skeletal maturity was determined using Risser, SSMS, TOCI and CVM for each patient. Crosstabulations of axial vs. appendicular markers were formed to analyze their concordance and discordance. Logistic and logarithmic regression models were run to assess longitudinal growth (postoperative height gain and leg-length growth) and curve modulation (follow-up instrumented Cobb correction after index operation), respectively. Models were compared using Akaike information criterion (AIC).

RESULTS

34 patients (32 F/2 M, mean age: 12.8 ± 1.5 years, mean follow-up: 47.7 (24-80) months) were included. The median preoperative maturity stages were: Risser: 1 (-1-4), SSMS: 4 (1-7), TOCI: 6 (1-8) and CVM: 4 (1-6). At latest follow-up, all patients reached skeletal maturity. Concordance and discordance were observed between axial vs. appendicular systems that demonstrated a range of possible distributions of CVM, where trunk peak height velocity occurred before, simultaneously with or after the standing height peak height velocity. R-squared values for Risser, SSMS, TOCI and CVM were 0.701, 0.783, 0.810 and 0.811, respectively, for prediction of final height; 0.759, 0.821, 0.831 and 0.775 for final leg-length, and 0.507, 0.588, 0.668 and 0.673 for curve modulation. Delta AIC values demonstrated that different skeletal maturity assessment methods provided distinctive information regarding follow-up height gain, leg-length growth and curve behavior.

CONCLUSIONS

Risser score provided considerably less information for all three outcome variables. TOCI and SSMS provided substantial information regarding remaining leg-length assessments, while in terms of assessment of total height gain and curve modulation after surgery, CVM and TOCI offered substantial information and SSMS offered strong information. Mutual use of axial and appendicular markers may provide valuable insight concerning timing of surgery and magnitude of surgical correction.

Evaluating the Feasibility of Cervical Vertebral Maturation Stages as an Alternative to Risser Sign in Assessing Skeletal Maturity in Adolescent Idiopathic Scoliosis Patients

BACKGROUND

Radiographic methods for evaluating skeletal maturity traditionally include the Risser sign and the hand-wrist maturation method. While the cervical vertebral maturation (CVM) stage is widely recognized in orthodontics, its application in assessing spinal growth, particularly in adolescent idiopathic scoliosis (AIS), has been less explored. This study explores the correlation between CVM, chronological age, and the Risser sign to evaluate the feasibility of CVM in assessing skeletal development in adolescents.

METHODS

This prospective study included AIS patients and asymptomatic adolescents, aged 7-15 years, who underwent full-spine imaging with clear visibility of the cervical and pelvic regions. The correlation between CVM and the Risser sign was analyzed. The height of the cervical C3-7 vertebral body was measured, and its growth trend with age was examined. Differences between AIS patients and asymptomatic adolescents were compared.

RESULTS

A total of 85 AIS patients (mean age 11.44 ± 2.36 years) and 47 asymptomatic adolescents (mean age 11.48 ± 3.14 years) were included. No statistically significant differences were observed in age, Risser sign grading, CVM staging, or C3-7 vertebral body height between the 2 groups. Chronological age showed a stronger correlation with CVM stages than with the Risser sign in both the AIS group (r = 0.93 vs. r = 0.82, P < 0.01) and the asymptomatic group (r = 0.81 vs. r = 0.72, P < 0.01).

CONCLUSIONS

The CVM stage, which shows a strong correlation with Risser sign grading, could serve as a reliable alternative for assessing skeletal maturity in adolescent subjects, particularly in clinical scenarios where minimizing radiation exposure is a priority.

Sagittal morphology of the cervical spine in adolescent idiopathic scoliosis: a retrospective case-control study

BACKGROUND

To investigate the relationship between sagittal alignment and coronal deformity in patients with adolescent idiopathic scoliosis (AIS) through analysis of the spinal imaging data.

METHODS

Four hundred and fifty-four AIS patients who underwent anteroposterior and lateral radiography of the while spine were enrolled, and the spinal parameters of Cobb angle, cervical lordosis, C1-C2 angle, T1 slope, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt (PT), pelvic incidence (PI), cervical sagittal vertical axis (SVA), and spinal SVA were analyzed.

RESULTS

The patients were divided into two groups according to the size of the Cobb angle: group A (Cobb angle ≤45°, n=414) and group B (Cobb angle >45°, n=40). In group A, the Cobb angle was in a medium negative correlation with the cervical lordosis angle (r=-0.637, P<0.001), a weak positive correlation (|r|<0.3, P<0.05) with C1-C2 angle, T1 slope and thoracic kyphosis. In group B, the Cobb angle was in a mild positive correlation (P<0.05) with PT (r=0.398) and PI (r=0.360). The cervical lordosis angle was significantly (P<0.05) different between male and female patients in both groups. In Group A, the cervical lordosis angle was in a significantly (P<0.01) positive correlation with the T1 slope (r=0.586), thoracic kyphosis (r=0.490), and sagittal vertical axis (r=0.135), and a significantly (P<0.01) negative correlation with cervical sagittal vertical axis (r=-0.128) and C1-C2 angle (r=-0.155). In group B, the cervical lordosis angle was in a significantly (P<0.05) positive correlation with T1 slope (r=0.661), thoracic kyphosis (r=0.608), lumbar lordosis (r=0.425), sacral slope (r=0.434), and sagittal vertical axis (r=0.335).

CONCLUSIONS

In AIS patients with the Cobb angle ≤45º, a significant negative correlation exists between the cervical lordosis and the Cobb angle. The sagittal morphology of the cervical spine in AIS patients is affected by the spinal coronal deformity, which plays an important role in the treatment of AIS.

Reliability of cervical vertebral maturation compared to hand-wrist for skeletal maturation assessment in growing subjects: A systematic review

BACKGROUND

Radiographic methods to assess skeletal maturity (SM) have a key role in adolescent idiopathic scoliosis (AIS) management, allowing to predict risk of spinal curve progression. Cervical vertebral maturation (CVM) has been recently introduced as an alternative tool to assess skeletal maturity; however, its clinical role is still debated.

OBJECTIVE

This systematic review aimed to investigate the reliability of CVM in the SM assessment of growing subjects, comparing it to hand wrist maturation (HVM).

METHODS

PubMed, Scopus, and Web of Science databases were systematically searched from inception until 31st December 2020 to identify observational studies presenting: growing subjects as participants; CVM methods as intervention; HVM methods as comparator; reliability for SM assessment as outcome. A 10-item quality tool has been used to assess study quality.

RESULTS

Out of 205 papers, 12 papers were included in the data synthesis. We classified 10 studies (83.3%) as medium-quality studies and 2 studies (16.7%) as high-quality studies. Eight studies reported a significant correlation between CVM Baccetti and different HWM methods.

CONCLUSION

Taken together, these findings suggested that CVM might be considered as reliable SM assessment method compared to HWM in growing subjects. However, further studies are warranted to confirm these findings.