Comparison of radiographic sagittal spinopelvic alignment between skeletally immature and skeletally mature individuals with Scheuermann's disease

Is sagittal spinopelvic alignment a cause of low back pain in pediatric spine pathologies? A review

Purpose

Altered spinopelvic morphology is observed in many spine pathologies occurring during growth. The aim of the study is to better understand the sagittal compensatory mechanisms and their possible influence on the occurrence of pain in selected pediatric spine pathologies.

Methods

A bibliographic search in the PubMed database included articles published between September 1965 and July 2023. The keywords contained in the search were "spondylolysis," "spondylolisthesis," "scoliosis," "kypho," "sagittal," "pediatric," "child," "adolescent," "grow," "development," and "pain."

Results

The largest diversity in sagittal alignment patterns was reported in idiopathic scoliosis, with global flattening of the spine being the most common. Kyphotic deformations occurring during growth are characterized by structural thoracic or thoracolumbar kyphosis compensated by lumbar hyperlordosis and lower pelvic incidence. Whereas in spondylolisthesis, altered morphology of the spinopelvic junction with high values of pelvic incidence is observed. Pain does not seem to be related to sagittal alignment in idiopathic scoliosis. In Scheuermann disease, it is localized at the apex of the deformity and is associated with the curve pattern, whereas in spondylolisthesis, sagittal alignment correlates with pain scores only in high-grade slips.

Conclusion

Most of the patients with spine disorders that occurred during growth present a clinically balanced posture in the sagittal plane. It suggests that compensatory mechanisms before achieving skeletal maturity are really significant. A comprehension of sagittal alignment in spine deformities and its relationship to pain is essential for the proper assessment and treatment of these disorders.

Effect of the type of brace on head to pelvis sagittal alignment of adolescents with Scheuermann's kyphosis

The aim of this study was to determine the effects of the Milwaukee brace and thoracolumbosacral orthosis (TLSO) on head to pelvis sagittal alignment in adolescents with Scheuermann's kyphosis (SK). A total of 52 adolescents with SK who were under brace treatment were studied. They underwent biplanar radiography of the head to pelvis (EOS Imaging, Paris, France) before and 6 months after the beginning of bracing. We measured T1 slope, neck tilt (NT), cervical sagittal vertical axis (cSVA), thoracic inlet angle (TIA), C0-C2 lordosis, C2-C7 lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA) and T1 spinopelvic inclination (T1SPi). There were no significant differences in baseline values of TIA, PT, SS, PI, SVA, TK, cSVA, NT and T1 slope between the two groups (p > 0.05). There were significant differences between the baseline and final measurements of T1 slope, cSVA, TK, LL, T1SPi and TIA in both groups (p < 0.05). The results imply that brace treatment can significantly affect head to pelvis sagittal parameters of adolescents with SK. However, there are no significant differences in the values of head to pelvis sagittal parameters when comparing short-term effect of TLSO and the Milwaukee brace.

The method for measurement of the three-dimensional scoliosis angle from standard radiographs

Background

Three-dimensional idiopathic scoliosis cannot be accurately assessed with the aid of a single plane parameter – the Cobb angle. We propose a novel method for evaluating the three-dimensional (3D) pattern of scoliosis based on two X-rays (PA and lateral). The proposed method consists of the measurements of the angles between the upper endplate of the upper-end vertebra and the lower endplate of the lower-end vertebra (3D scoliosis angle).

Methods

The 3D-angles of thirty scoliosis curves were measured with either computed tomography (CT) or digitally reconstructed radiographs (DRRs): PA and lateral. CT was used as a reference. In the case of CT, the 3D angle was calculated based on the coordinates of three points situated on the upper endplate and those of three points situated on the lower endplate of the scoliosis curve. In the case of the DRR, the 3D angle was calculated using the four-angle method: the angles formed by the endplates of the curve with the transverse plane. The results were tested with the Student’s t-test, and the agreement of measurements was tested with the intraclass correlation coefficient.

Results

There was no significant difference between the 3D-angle measurements obtained with DRRs versus CT, p > 0.05. There was, however, a significant difference between the 3D-scoliosis angle and the Cobb angle measurements performed based on the X-rays. The reproducibility and reliability of 3D angle measurements were high.

Conclusions

Based on two standard radiographs, PA and lateral, it is possible to calculate the 3D scoliosis angle. The proposed method facilitates 3D-scoliosis assessment without the use of sophisticated devices. Considering the 3D nature of AIS, the 3D parameters of the spine may help to apply a more effective treatment and estimate a more precise prognosis for patient with scoliosis.

Sagittal Spinal and Pelvic Parameters in Patients With Scheuermann's Disease: A Preliminary Study

Background

Sagittal spinopelvic parameters remain poorly defined in patients with Scheuermann disease (SD). For example, although pelvic incidence (PI) should approximate lumbar lordosis (LL) by 10°, this is not true in patients with SD. This retrospective radiographic study was conducted to propose a new mathematical relationship between sagittal spinopelvic parameters in skeletally mature patients with SD.

Methods

The following formula (Δ) was proposed [(thoracic kyphosis - 45°) + (thoracolumbar kyphosis - 0°) + (PI - LL) = ± 10°] and validated with standard spino pelvic parameters in patients with skeletally mature SD without prior spine surgery at 2 centers between 2006 and 2015. The T1 pelvic angle (TPA) was used as a measure of global balance with normal maximum of 15°. Subgroup analysis was performed to compare Δ between balanced (TPA ≤ 15°) and unbalanced (TPA > 15°) patients with SD.

Results

In patients with SD (n = 30), half were female (n = 15), the average age was 39 years, and the average Δ was 2.4°. A significant correlation was discovered between Δ and both TPA (R ² = 0.75) and PI (R ² = 0.69). At TPA of 15°, average Δ was 9.2°. There was also a significant difference between balanced and unbalanced patients (-8.7° ± 11.6° versus 28.2° ± 19.7°, P = .0003).

Conclusions

This study of a new formula (Δ) to evaluate global sagittal balance in patients with SD found that accounting for the kyphosis maintained Δ within ± 10°. Further study is planned to determine whether maintaining and/or restoring a normal Δ is associated with improved outcomes in patients with SD after surgery.

What Are the Indications for Spinal Fusion Surgery in Scheuermann Kyphosis?

BACKGROUND

Surgical indications for Scheuermann kyphosis are variable. We sought to evaluate the characteristics of patients undergoing operative versus nonoperative treatment of Scheuermann kyphosis to better understand current practices and the factors which contribute to the decision for surgical management.

METHODS

Multicenter prospective cohort study. We evaluated consecutive patients presenting with Scheuermann kyphosis. Patients underwent either surgical or nonoperative management according to surgeon and patient discretion. Preoperative patient-reported outcome measures (Scoliosis Research Society and Spinal Appearance Questionnaire scores), demographics, and radiographic characteristics were assessed.

RESULTS

Overall, 150 patients with Scheuermann kyphosis were enrolled, with 77 choosing nonoperative treatment and 73 treated operatively. Compared with the nonoperative cohort, patients treated operatively were older (16.3±2.0 vs. 15.1±2.2, P=0.0004), and had higher body mass index (26.3±7.2 vs. 22.7±6.5, P=0.003), had greater T2-T12 kyphosis (71±14 degrees vs. 61±12 degrees, P<0.001), increased pelvic incidence (46 vs. 41 degrees, P=0.03) and pelvic tilt (10 vs. 3 degrees, P=0.03). There was no detected difference in maximal sagittal Cobb angle in the operative versus nonoperative patients (73±11 vs. 70±12 degrees, P=0.11). Functionally, the operative patients had worse Scoliosis Research Society pain scores (3.7±0.9 vs. 4.1±0.7, P=0.0027) and appearance scores (2.9±0.7 vs. 3.4±0.8, P <0.0001).

CONCLUSIONS

Patients undergoing surgical management of Scheuermann disease were more likely to have large body mass index and worse pain scores. Other factors beyond radiographic measurement likely contribute to the decision for surgical management of Scheuermann kyphosis.

LEVEL OF EVIDENCE

Level II.

Pelvic incidence variation among individuals: functional influence versus genetic determinism

Pelvic incidence has become one of the most important sagittal parameters in spinal surgery. Despite its great importance, pelvic incidence can vary from 33° to 85° in the normal population. The reasons for this great variability in pelvic incidence remain unexplored. The objective of this article is to present some possible interpretations for the great variability in pelvic incidence under both normal and pathological conditions and to further understand the determinants of pelvic incidence from the perspective of the functional requirements for bipedalism and genetic backgrounds via a literature review. We postulate that both pelvic incidence and pelvic morphology may be genetically predetermined, and a great variability in pelvic incidence may already exist even before birth. This great variability may also serve as a further reminder that the sagittal profile, bipedal locomotion mode, and genetic background of every individual are unique and specific, and clinicians should avoid making universally applying broad generalizations of pelvic incidence. Although PI is an important parameter and there are many theories behind its variability, we still do not have clear mechanistic answers.

Two-dimensional digital photography for child body posture evaluation: standardized technique, reliable parameters and normative data for age 7-10 years

BACKGROUND

Digital photogrammetry provides measurements of body angles or distances which allow for quantitative posture assessment with or without the use of external markers. It is becoming an increasingly popular tool for the assessment of the musculoskeletal system. The aim of this paper is to present a structured method for the analysis of posture and its changes using a standardized digital photography technique.

MATERIAL AND METHODS

The purpose of the study was twofold. The first one comprised 91 children (44 girls and 47 boys) aged 7-10 (8.2 ± 1.0), i.e., students of primary school, and its aim was to develop the photographic method, choose the quantitative parameters, and determine the intraobserver reliability (repeatability) along with the interobserver reliability (reproducibility) measurements in sagittal plane using digital photography, as well as to compare the Rippstein plurimeter and digital photography measurements. The second one involved 7782 children (3804 girls, 3978 boys) aged 7-10 (8.4 ± 0.5), who underwent digital photography postural screening. The methods consisted in measuring and calculating selected parameters, establishing the normal ranges of photographic parameters, presenting percentile charts, as well as noticing common pitfalls and possible sources of errors in digital photography.

RESULTS

A standardized procedure for the photographic evaluation of child body posture was presented. The photographic measurements revealed very good intra- and inter-rater reliability regarding the five sagittal parameters and good reliability performed against Rippstein plurimeter measurements. The parameters displayed insignificant variability over time. Normative data were calculated based on photographic assessment, while the percentile charts were provided to serve as reference values. The technical errors observed during photogrammetry are carefully discussed in this article.

CONCLUSIONS

Technical developments are allowed for the regular use of digital photogrammetry in body posture assessment. Specific child positioning (described above) enables us to avoid incidentally modified posture. Image registration is simple, quick, harmless, and cost-effective. The semi-automatic image analysis, together with the normal values and percentile charts, makes the technique reliable in terms of child's posture documentation and corrective therapy effects' monitoring.

Influence of patient rotational malpositioning on pelvic parameters assessed on lateral radiographs

AIM

To estimate the effect of patients' axial rotation (AR) during pelvic radiograph acquisition, on the reliability and validity of sagittal pelvic parameters.

MATERIALS AND METHODS

Lateral digitally reconstructed radiographs (LDRRs) were obtained from the pelvic computed tomography (CT) scans of eight children and nine adults. Then, the AR of the pelvis was simulated and the corresponding LDRRs were reconstructed at 5°, 10°, 15°, and 20° of the AR. Pelvic parameters were measured digitally on each radiograph. Intra- and interobserver variability were evaluated at each AR position (three operators repeated the measurements three times each). The bias on each clinical parameter, in each AR position, was calculated relatively to the 0° position.

RESULTS

Interobserver variability increased similarly in children and adults with AR. It reached 4.4° for pelvic incidence and 4.7° for the sacral slope at 20° of AR. Biases on radiological parameters increased with AR and exceeded the acceptable threshold of errors when AR reached 10°. A linear regression was established (R²=0.834, p<0.0001) in order to estimate the AR of a patient on a lateral pelvic radiograph based on the measurement of the bifemoral distance normalized to the sagittal pelvic thickness.

CONCLUSIONS

AR of patients during radiograph acquisition can be estimated in clinical practice, which would allow physicians to discard any radiographs where the calculated AR exceeded 10°.

Sacral orientation and Scheuermann's kyphosis

To examine whether the association between spinal alignment and sacral anatomical orientation (SAO) can be detected in skeletal populations, by comparing SAO values in individuals with a typical SD to individuals with normal spinal alignment. 2025 skeletons were screened for Scheuermann's disease. Scheuermann's kyphosis was established by the presence of apophyseal abnormalities associated with more than 5° of anterior wedging in each of three adjacent vertebrae. SAO was measured as the angle created between the intersection of a line running parallel to the superior surface of the sacrum and a line running between the anterior superior iliac spine and the anterior-superior edge of the symphysis pubis (PUBIS). SAO was measured on 185 individuals with normal spines and 183 individuals with Scheuermann's kyphosis. Out of 2025 skeletons, 183 (9 %) were diagnosed with Scheuermann's kyphosis. The sacrum was significantly more horizontally oriented in individuals with Scheuermann's kyphosis compared with the control (SAO: 44.44 ± 9.7° vs. 50 ± 9.9°, p < 0.001). Alteration in spinal biomechanics due to a horizontally orientated sacrum may be an important contributing factor for the development of Scheuermann's kyphosis.

Cervical Sagittal Alignment in Scheuermann Disease

STUDY DESIGN

Retrospective evaluation of radiographs.

OBJECTIVE

The aim of this study was to assess sagittal cervical balance in patients with the two types Scheuermann disease (SD).

SUMMARY OF BACKGROUND DATA

The structural hyperkyphosis characterizing SD may be localized in the thoracic (SDT) or thoraco-lumbar (SDTL) spine segments. This may affect sagittal cervical balance.

METHODS

Seventy-one patients (41 males and 30 females), aged 16.3 ± 3.8 years with SD, were enrolled into the study. On standing lateral long-cassette radiographs, the following measurements were made: C0-2 angle, C2-7 angle (CL), C1-C2 angle, relative rotation angle (RRA)-measured at levels from C2 to C7, cervical tilt (CT), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), C0-angle, cranial offset (CO), and cranial tilt (CRT). Comparison with t test was performed with significance level P < 0.05.

RESULTS

There were 38 SDT and 33 SDTL patients. In SDT, the T1 slope was significantly greater than that in SDTL (38.1° vs. 28.9°; P = 0.0002), and consequently CL (-19.8° vs. -8.9°; P = 0.0160), CT (29.8° vs. 24.3°; P = 0.0190), and TIA (81.9° vs. 71.1°; P = 0.0022) in SDT were significantly greater as well. The difference in CL was expressed mainly in C6-C5 (-4.8° vs. -1.4°; P = 0.0146) and C5-C4 (-4.4°; vs. -1.5° P = 0.0464) segments. There were no significant differences in proximal cervical lordosis: C0-2 angle (-21.6° vs. -20.8°; P = 0.7597), C1-C2 angle (-30.8°vs. -27.5°; P = 0.1746), C3-C2 (-5.4° vs. -5.1°; P = 0.7976), and C4-C3 (3.5° vs. -1.5°; P = 0.1464) segments. There was no significant difference in cranial parameters C0-angle, CRT, and CO.

CONCLUSION

Scheuermann disease type has an influence on cervical sagittal balance. Localization of structural kyphosis affects the T1 slope as well as C2-C7 lordosis, cervical tilt, and thoracic inlet angle. Significant difference in C2-C7 lordosis in comparison to similar C0-2 lordosis demonstrates that compensation is present in subaxial cervical spine. Position of the head center of gravity is not dependent on the SD type.

LEVEL OF EVIDENCE

4.