Analysis of sagittal alignment in thoracic and thoracolumbar curves in adolescent idiopathic scoliosis: how do these two curve types differ?

Imaging study of coccygeal morphology in adolescent idiopathic scoliosis

The correlation between scoliosis and sagittal curvature of the cervical, thoracic, and lumbar spine have already been reported in previous studies. However, as a part of the spine, the change in coccygeal morphology in AIS patients has not yet been studied. In this study, a retrospective analysis was performed on 400 patients who were divided into a non-scoliotic group (206 patients) and an AIS group (194 patients). The Postacchini coccygeal radiological classification that was modified by Nathan was used to observe and compare the sagittal coccygeal morphology between the two groups. The results showed that the non-scoliotic group had the highest percentage (52.4%) of patients with type I and the lowest (3.4%) proportion of patients with type V; moreover, the AIS group had the highest percentage (69.1%) of patients with type I and the lowest (1.5%) proportion of patients with type V. The coccygeal morphology was significantly different between the non-scoliotic group and the AIS group (P = 0.001). No significant differences in coccygeal morphology were found between the males and females in the two groups (mild and moderate scoliosis and different segmental scoliosis). In addition, a significant correlation between coccygeal morphology and scoliosis (P = 0.035) was found. In conclusion, coccygeal morphology significantly differs between AIS patients and non-scoliotic adolescents. There was a smaller proportion of patients with a type I coccyx and a larger proportion of patients with a type II or type III coccyx in the AIS group than in the non-scoliotic group. In other words, the presence of a more pronounced coccygeal curve in AIS patients may be caused by an incorrect sitting position and an imbalance in the contraction of the pelvic muscles. It should be further studied whether correcting the sitting position and muscular imbalances could change coccygeal morphology and subsequently affect the development of AIS.

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.

Is the pelvic incidence a determinant factor for kyphosis curve patterns of ankylosing spondylitis patients?

To investigate the influence of pelvic incidence (PI) on the kyphosis curve patterns and clinical outcomes in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis and to construct a classification of AS according to the PI value for surgical decision-making. 107 AS patients underwent single-level lumbar pedicle subtraction osteotomy (PSO) and finished a minimal of 2-year follow-up. All patients were divided into three groups: low PI (PI ≤ 40°), moderate PI (40° < PI ≤ 60°), and high PI (PI > 60°). Standing lateral radiographs were taken to evaluate the location of kyphotic apex, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (SVA), spino-sacral angle (SSA), global kyphosis (GK), PI, sacral slope (SS), and pelvic tilt (PT). Visual Analogue Scale (VAS) score, Oswestry Disability Index (ODI) and Bath Ankylosing Spondylitis Functional Index (BASFI) were used to evaluate quality of life. Before surgery, a significant difference was shown in the average LL and the mean GK in high PI group was the largest among the three groups. Correction of SVA, GK and LL in high PI group was the smallest among the three group. No significant difference in clinical outcomes was found among the three groups before surgery and at the final follow-up. Regarding the preoperative sagittal profile, the kyphosis curve pattern of moderate PI group is similar to that of low PI group. For AS patients in these two groups, harmonious sagittal alignment can be restored by a single-level PSO. However, the sagittal imbalance is insufficiently realigned by a single-level PSO in a patient with high PI.

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.

Reciprocal Change of Cervical Spine after Posterior Spinal Fusion for Lenke Type 1 and 2 Adolescent Idiopathic Scoliosis

Reciprocal sagittal alignment changes after adolescent idiopathic scoliosis (AIS) posterior corrective surgery have been reported in the cervical spine, but the evidence is not yet sufficient. Furthermore, much remains unknown about the effects of cervical kyphosis on clinical outcomes in AIS. Forty-five consecutive patients (4 males and 41 females) with AIS and Lenke type 1 or 2 curves underwent a posterior spinal fusion, and a minimum of 24-month follow-up was collected from our prospective database. We investigated radiographic parameters and SRS-22r. Before surgery, cervical kyphosis (cervical lordosis < 0°) was present in 89% and cervical hyperkyphosis (cervical lordosis < -10°) in 60%. There were no significant differences in age, sex, or Lenke type between the hyperkyphosis and the non-hyperkyphosis groups. Although cervical lordosis increased significantly after surgery, cervical kyphosis was observed in 73% of patients 2 years after surgery. We found a significant correlation between Δthoracic kyphosis (TK) and Δcervical lordosis. Preoperative cervical kyphosis, ΔT1 slope, and ΔTK were independently associated factors for postoperative cervical hyperkyphosis. The cervical hyperkyphosis group had significantly lower SRS-22r domains. In AIS corrective surgery, restoring TK leading to a gain of T1 slope may lead to an improvement of cervical sagittal alignment. Remaining cervical hyperkyphosis after AIS surgery may affect clinical outcomes.

Characteristics of Sagittal Alignment in Patients with Severe and Rigid Scoliosis

OBJECTIVE

There has been increasing concern about the importance of sagittal alignment in the evaluation and treatment of spinal scoliosis. However, recent studies have only focused on patients with mild to moderate scoliosis. To date, little is known about the sagittal alignment in patients with severe and rigid scoliosis (SRS). This study was performed to evaluate the sagittal alignment in patients with SRS, and to analyze how it was altered after corrective surgery.

METHODS

In this retrospective cohort study, we included 58 patients with SRS who underwent surgery from January 2015 to April 2020. Preoperative and postoperative radiographs were reviewed, and the sagittal parameters mainly included thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacrum slope (SS), and sagittal vertical axis (SVA). The sagittal balance state was evaluated according to whether the PI minus the LL (PI-LL) was less than 9°, and the patients were divided into thoracic hyperkyphosis and normal groups based on whether the TK exceeded 40°. The Student's t test, Pearson's test, and Receiver operating characteristic (ROC) curve analysis were used to compare related parameters between the different groups.

RESULTS

The mean follow-up duration was 2.8 years. Preoperatively, the mean PI was 43.6 ± 9.4°, and the mean LL was 65.2 ± 13.9°. Sixty-nine percent of patients showed sagittal imbalance, and they showed larger TK and LL values and smaller PI and SVA values than those with sagittal balance. Additionally, most patients (44/58) presented with thoracic hyperkyphosis; this group had smaller PI and SVA values than the normal patients. Patients with syringomyelia-associated scoliosis were more likely to present with thoracic hyperkyphosis. The TK and LL values were significantly decreased, and 45% of patients with preoperative sagittal imbalance recovered after surgery. These patients had a larger PI (46.4 ± 9.0° vs 38.3 ± 8.8°, P = 0.003) and a smaller TK (25.5 ± 5.2° vs 36.3 ± 8.0°, P = 0.000) at the final follow-up.

CONCLUSION

Preoperative sagittal imbalance appears in the majority of SRS patients, accounting for approximately 69% of our cohort. Patients with small PI values or syringomyelia-associated scoliosis were more likely to present with thoracic hyperkyphosis. Sagittal imbalance can generally be corrected by surgery, except in patients with a PI less than 39°. To achieve good postoperative sagittal alignment, we recommend controlling the TK to within 31°.

How to make a more optimal surgical plan for Lenke 5 adolescent idiopathic scoliosis patients: a comparative study based on the changes of the sagittal alignment and selection of the lowest instrumented vertebra

BACKGROUND

The treatment of patients with Lenke 5 adolescent idiopathic scoliosis (AIS) is closely related to the pelvic because the spine-pelvis is an interacting whole. Besides, the choice of fusion segment is a significant issue; with the optimal choice, there will be fewer complications and restoring the pelvic morphology to some extent. This study aims to analyze the impact of changes in sagittal parameters and selection of the lowest instrumented vertebra (LIV) on spine and pelvic morphology for better surgical strategy.

METHOD

Ninety-four patients with Lenke 5 AIS who underwent selective posterior thoracolumbar/lumbar (TL/L) curve fusion were included in the study and grouped according to pelvic morphology and position of LIV. Spinopelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up. The patient's preoperative and last follow-up quality of life was assessed with the MOS item short-form health survey (SF-36) and scoliosis research society 22-item (SRS-22).

RESULT

Patients being posterior pelvic tilt had the oldest mean age (P = 0.010), the smallest lumbar lordosis (LL) (P = 0.036), the smallest thoracic kyphosis (TK) (P = 0.399) as well as the smallest proximal junctional angle (PJA) while those being anterior pelvic tilt had the largest PJA. The follow-up TK significantly increased in both groups of anterior and normal pelvic tilt (P < 0.039, P < 0.006) while no significant changes were observed in the posterior pelvic tilt group. When LIV is above L4, the follow-up PJA was larger than other groups (P = 0.049, P = 0.006). When LIV is below L4, the follow-up TK and PT were larger and LL was smaller than other groups(P < 0.05). The SF-36 and SRS-22 scores were better in the LIV = L4 group than in other groups at the last follow-up (P < 0.05).

CONCLUSION

The correction of TK and LL after surgery can improve pelvic morphology. Besides, LIV is best set at L4, which will facilitate the recovery of TK, the improvement of symptoms, and the prevention of complications and pelvic deformities. Level of evidence Level III.

The relationship between spino-pelvic alignment and primary dysmenorrhea

Introduction

Most women of reproductive age suffered from the primary dysmenorrhea (PD). Up to date, most studies on the etiology of dysmenorrhea focused on endocrine factors while ignored the effect of spino-pelvic bony anatomy on uterus. In this study, we innovatively shed light on the relationship between primary dysmenorrhea and sagittal spino-pelvic alignment.

Materials and Methods

120 patients diagnosed with primary dysmenorrhea and a control group of 118 healthy volunteers were enrolled into this study. All subjects received the standing full-length posteroanterior plain radiography to evaluate the sagittal spino-pelvic parameters. The visual analog scale (VAS) was used to assess pain rating of primary dysmenorrhea patients. Analysis of variance (ANOVA) or Student's t test was performed to measure statistical significance between differences.

Results

There was a significant difference in pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL) and thoracic kyphosis (TK) between PD group and Normal group (P<0.05). Furthermore, in PD group, the PI and SS was significant different between mild pain group and moderate pain group (P<0.05) and there was a significant negative correlation between pain rating and SS. From the perspective of sagittal spinal alignment, the majority of PD patients were classified with Roussouly type 2, meanwhile most normal people were classified with Roussouly type 3.

Conclusion

Sagittal spino-pelvic alignment was related to primary dysmenorrhea symptoms. Lower SS and PI angles may contribute to a worsen pain in PD patients.

Does the Level of Pedicle Subtraction Osteotomy Affect the Surgical Outcomes in Ankylosing Spondylitis-Related Thoracolumbar Kyphosis With the Same Curve Pattern?

STUDY DESIGN

A retrospective study.

OBJECTIVE

To investigate the effect of pedicle subtraction osteotomy (PSO) level on the surgical outcomes in ankylosing spondylitis-related thoracolumbar kyphosis with the same curve pattern.

METHODS

ankylosing spondylitis (AS) patients with thoracolumbar kyphosis, who underwent 1-level lumbar PSO between March 2006 and June 2017, were retrospectively reviewed. Criteria for curve-matched thoracolumbar kyphosis were: (1) have same level of preoperative apex (pre-apex); (2) have similar global kyphosis (GK, the angle between the superior/inferior endplate of the maximally tilted upper and lower end vertebra) (the difference of GK less than 15˚). The radiographic parameters measured were sagittal vertical axis (SVA, the horizontal distance between the C7 plumb line and the posterosuperior corner of the S1), GK, thoracic kyphosis (TK, the angle between the T5 superior endplate and the T12 inferior endplate), lumbar lordosis (LL, the angle between the L1 and S1 superior endplate), sacral slope (SS, the angle between the sacral endplate and the horizontal line), pelvic tilt (PT, the angle between the vertical and the line joining the midpoint of the sacral plate and hip axis), and pelvic incidence (PI, the angle between the line vertical to the superior margin of S1 and the line connecting the sacral plate midpoint with the hip joint axis). All of these parameters and health-related quality of life (HRQoL, evaluated by preoperative and the last follow-up questionnaires including ODI and VAS) scores were collected before surgery and at the last follow-up. According to their osteotomy level, patients were devided into 2 sub-groups (L1 group and L2 group), and differences of these mentioned parameters between 2 groups were compared.

RESULTS

26 curve-matched patients were recruited with a mean follow-up of 37.2 months. All patients improved significantly after surgery in HRQoL scores (VAS 1.6 vs 5.4, P < 0.001; ODI 11.9 vs 26.4, P < 0.001). Except for TK and PI, those radiographic parameters were also observed to be significantly changed after surgery. Compared to L2 group, PSO at L1 may have larger correction of TK (ΔTK -6.8 vs -0.3°, P = 0.164), PI (ΔPI -7.4 vs -0.7°, P = 0.364) and smaller correction of SVA (ΔSVA -105.3 vs -128.5 mm, P = 0.096), LL (ΔLL -31.1 vs -43.0°, P = 0.307) and SS (ΔSS 6.9 vs 12.2°, P = 0.279) but had no statistical significance.

CONCLUSION

The results of this investigation showed that in AS-related thoracolumbar kyphosis patients with the same curve pattern, the different levels of osteotomy had little effect on the improvement of surgical outcomes. However, osteotomy at L2 is more likely to obtain a larger correction of SVA compared to osteotomy at L1.

Thoracic kyphosis in light of lumbosacral alignment in thoracic adolescent idiopathic scoliosis: recognition of thoracic hypokyphosis and therapeutic implications

BACKGROUND

The uniqueness of spinal sagittal alignment in thoracic adolescent idiopathic scoliosis (AIS), for example, the drastically smaller thoracic kyphosis seen in some patients, has been recognized but not yet fully understood. The purpose of this study was to clarify the characteristics of sagittal alignment of thoracic AIS and to determine the contributing factors.

METHODS

Whole spine radiographs of 83 thoracic AIS patients (73 females) were analyzed. The measured radiographic parameters were the Cobb angle of thoracic scoliosis, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (C7 SVA), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Additionally, max-LL, which was defined as the maximum lordosis angle from the S1 endplate, the inflection point between thoracic kyphosis and lumbar lordosis, and the SVA of the inflection point (IP SVA) were measured. The factors significantly related to a decrease in TK were assessed by stepwise logistic regression analysis. In addition, cluster analysis was performed to classify the global sagittal alignment.

RESULTS

The significant factors for a decrease in TK were an increase in SS (p = 0.0003, [OR]: 1.16) and a decrease in max-LL (p = 0.0005, [OR]: 0.89). According to the cluster analysis, the global sagittal alignment was categorized into the following three types: Type 1 (low SS, low max-LL, n = 28); Type 2 (high SS, low max-LL, n = 22); and Type 3 (high SS, high max-LL, n = 33).

CONCLUSIONS

In thoracic AIS, a decreased TK corresponded to an increased SS or a decreased max-LL. The sagittal alignment of thoracic AIS patients could be classified into three types based on SS and max-LL. One of these three types includes the unique sagittal profile of very small TK.

Assessment of the axial plane deformity in subjects with adolescent idiopathic scoliosis and its relationship to the frontal and sagittal planes

PURPOSE

Investigate the axial plane deformity in the scoliotic segment and its relationship to the deformity in the frontal and sagittal planes.

METHODS

Two hundred subjects with AIS (Cobb ≥ 20°) underwent low dose biplanar X-rays with 3D reconstruction of the spine and pelvis. All structural curves were considered and were distributed as follows: 142 thoracic (T), 70 thoracolumbar (TL), and 47 lumbar curves (L). Common 3D spino-pelvic and scoliosis parameters were collected such as: frontal Cobb; torsion index (TI); hypokyphosis/lordosis index (HI). Parameters were compared between each type of curvature and correlations were investigated between the 3 planes.

RESULTS

Frontal Cobb was higher in all T (45 ± 19°) and TL (41 ± 15°) curves compared to L curves (35 ± 14°, p = 0.004). TI was higher in T curves when compared to TL and L curves (TI: 15 ± 8°, 9 ± 6°, 7 ± 5°, p < 0.001). HI was similar between curve types. T curves showed significant correlations between the 3 planes: Cobb vs. TI (r = 0.76), Cobb vs. HI (r = - 0.54) and HI vs. TI (r = - 0.42). The axial plane deformity was related to the frontal deformity and the type of curvature (adjusted-R² = 0.6).

CONCLUSION

Beside showing the most severe deformity frontally and axially compared to TL and L curves, the T curves showed strong correlations between the 3 planes of the deformity. Moreover, this study showed that the axial plane deformity cannot be fully determined by the frontal and sagittal deformities, which highlights the importance of 3D assessment in the setting of AIS.

Sagittal spinopelvic alignment in tethered cord syndrome and split cord malformation

PURPOSE

Sagittal imbalance is common in degenerative and congenital spinal diseases. Some studies have examined spinal deformities in the spina bifida. However, sagittal spinopelvic parameters in tethered cord syndrome (TCS) and split cord malformation (SCM) have been poorly evaluated in the literature. In this study, we investigated sagittal spinopelvic differences in TCS due to fatty filum terminale and SCM patients.

MATERIAL AND METHODS

A total of 78 patients with spina bifida occulta (30 SCM and 48 TCS due to fatty filum terminale) were included in the study. Radiological images of these patients were retrospectively evaluated. We evaluated the pelvic incidence, pelvic tilt, sacral slope, sagittal vertical axis (SVA), T1 pelvic angle, lumbar lordosis (LL), thoracic kyphosis, thoracolumbar alignment, and change in those parameters with age.

RESULTS

Correlation coefficients between age and LL, T1 pelvic angle, and the SVA in patients with TCS due to fatty filum terminale were statistically significant. In addition, correlation coefficients between age and LL and the SVA in patients with SCM were statistically significant. Notably, LL was increased at a statistically significant level with age in patients with TCS and SCM.

CONCLUSION

Improved knowledge of spinal balance parameters in patients with TCS and SCM may be helpful in understanding the clinical course of these pathologies, and provide information regarding the success of surgery at the follow-up period.

PRE- AND POSTOPERATIVE COMPARATIVE ANALYSIS OF THE SPINOPELVIC AND GLOBAL SAGITTAL PARAMETERS OF PATIENTS WITH ADOLESCENT IDIOPATHIC SCOLIOSIS

ABSTRACT Objective: To analyze the pre- and postoperative spinopelvic parameters and global sagittal balance of patients with adolescent idiopathic scoliosis (AIS) divided into 3 groups (Group 1 – thoracic arthrodesis, Group 2 - thoracolumbar arthrodesis, and Group 3 – lumbar arthrodesis), observing differences in these two moments and whether the parameter values are maintained or not over a period of up to 2 years following surgery. Methods: We analyzed the radiographs from a single-center database of 99 patients who underwent arthrodesis with posterior instrumentation. Pelvic incidence, pelvic version, sacral slope, lumbar lordosis, thoracic kyphosis, and sagittal vertical axis values were measured in the pre- and postoperative radiographies of each patient. Results: The parameters of pelvic incidence, pelvic version, sacral slope, and sagittal vertical axis did not show statistically significant differences among the 3 groups. There was a difference in preoperative lumbar lordosis between the 3 groups (p = 0.049). Thoracic kyphosis showed differences both in the pre- (p = 0.015) and postoperative (p = 0.042) values, in addition to demonstrating a relationship of dependence between the pre- and postoperative values in the final statistical analysis. Conclusion: The evaluation of the parameters analyzed shows that the study groups have similar values of individual balance, with the exception of thoracic kyphosis and lumbar lordosis, which are measurements that depend on the surgical technique and compensatory mechanisms, but remained within normal ranges. These factors allow the surgeon to be attentive to both the coronal and sagittal planes when planning the correction in order to achieve the equilibrium of the trunk in addition to correction of the deformity. Level of Evidence IIIA: Comparative retrospective study.

Assessment of sagittal spinopelvic alignment in asymptomatic Chinese juveniles and adolescents: a large cohort study and comparative meta-analysis

STUDY DESIGN

Retrospective study and comparative meta-analysis.

OBJECTIVE

To document the sagittal spinopelvic alignment in a large cohort study in asymptomatic Chinese juveniles and adolescents, and to explore whether these parameters were different from various regions using meta-analysis.

METHODS

Medical records of 656 asymptomatic Chinese juveniles and adolescents were reviewed, whose mean age was 13.14 ± 3.41 years old, including 254 male and 402 female volunteers. Demographic and lateral radiological parameters were evaluated. Furthermore, a systematic online search was performed to identify eligible studies. Weight mean difference (WMD) with 95% confidence interval (CI) were used to evaluate whether these sagittal parameters were different from various regions.

RESULTS

The mean value of sagittal spinopelvic alignment in this study was calculated and analyzed respectively. Significant differences of PI (34.20 ± 4.00 vs. 43.18 ± 7.12, P < 0.001) and PT (3.99 ± 6.04 vs. 8.42 ± 7.08, P < 0.001) were found between juveniles and adolescents. A total of 17 studies were recruited for meta-analysis. For juvenile populations, TK, PI and SS of Caucasians were significantly larger than those of our study (all P < 0.001). As for adolescent populations, PI (P = 0.017), TK (P = 0.017) and SS (P < 0.001) of Caucasians was found to be greater when compared with that of our study. All in all, TK, PI and SS in Chinese pre-adult populations were significantly smaller than those populations in Caucasian regions (all P < 0.001).

CONCLUSION

Our study was the first large-scale study that reported the mean values of sagittal parameters in asymptomatic Chinese juveniles and adolescents. There were significant differences in TK, PI and SS between our study and other previous reported populations, which reminded us for using specific mean values in different populations when restoring a relatively normal sagittal spinopelvic balance in spinal deformity.

Global sagittal alignment after surgery of right thoracic idiopathic scoliosis in adolescents and adults with and without thoracic hypokyphosis

This study aimed to characterize global sagittal alignment in adolescent idiopathic scoliosis (AIS) with normal kyphosis (NTK, kyphosis > 10°) and with thoracic hypokyphosis (THK, kyphosis < 10°), before and after posterior spinal fusion, and compare them with asymptomatic controls. 27 AIS girls and young adults with right thoracic curves were included (seventeen with age ≤ 18 years, then age > 21). Biplanar radiographies were acquired at baseline, immediate post-operatively, 1-year and 2-year follow-up, and 3D reconstruction of the spine and pelvis was performed. NTK and THK showed different global sagittal alignment, as well as differences compared to controls. AIS with THK at baseline had higher SVA/SFD (2.0 ± 2.9 vs - 0.4 ± 1.9; P < 0.05) and OD-HA (0.2 ± 1.4° vs - 1.3 ± 1.6°; P < 0.05) than controls, indicating that THK had compensated balance with unusual forward leaning posture. Immediately post-operation, SVA/SFD remained high (1.3 ± 3.0) while OD-HA reversed (- 1.2 ± 1.7°), indicating that THK patients had found partially compensated balance. After 2-yeas, both SVA/SFD (- 1.3 ± 2.1) and OD-HA (- 1.4 ± 0.9°) were normalized. The changes in global sagittal alignment and mechanism of balance are different in AIS with or without THK. As the head plays a critical role on balance during immediate and delayed post-operation, OD-HA can be complementary parameter for assessing global balance during post-operative follow-up of AIS patients with THK.

Specific sagittal alignment patterns are already present in mild adolescent idiopathic scoliosis

PURPOSE

The complex three-dimensional spinal deformity in AIS consists of rotated, lordotic apical areas and neutral junctional zones that modify the spine's sagittal profile. Recently, three specific patterns of thoracic sagittal 'malalignment' were described for severe AIS. The aim of this study is to define whether specific patterns of pathological sagittal alignment are already present in mild AIS.

METHODS

Lateral spinal radiographs of 192 mild (10°-20°) and 253 severe (> 45°) AIS patients and 156 controls were derived from an international consortium. Kyphosis characteristics (T4-T12 thoracic kyphosis, T10-L2 angle, C7 slope, location of the apex of kyphosis and of the inflection point) and sagittal curve types according to Abelin-Genevois were systematically compared between the three cohorts.

RESULTS

Even in mild thoracic AIS, already 49% of the curves presented sagittal malalignment, mostly thoracic hypokyphosis, whereas only 13% of the (thoraco) lumbar curves and 6% of the nonscoliosis adolescents were hypokyphotic. In severe AIS, 63% had a sagittal malalignment. Hypokyphosis + thoracolumbar kyphosis occurred more frequently in high-PI and primary lumbar curves, whereas cervicothoracic kyphosis occurred more in double thoracic curves.

CONCLUSIONS

Pathological sagittal patterns are often already present in curves 10°-20°, whereas those are rare in non-scoliotic adolescents. This suggests that sagittal 'malalignment' patterns are an integral part of the early pathogenesis of AIS.

A Retrospective Study of Factors Associated with Restoration of Thoracic Kyphosis in 43 Patients with Adolescent Idiopathic Scoliosis with Lenke Type 1 Curvature

BACKGROUND This retrospective study aimed to identify the factors associated with successful surgical correction of thoracic kyphosis (TK) in 43 patients with adolescent idiopathic scoliosis (AIS) with Lenke type 1 curvature, in which the major curve with the largest Cobb angle was mainly in the thoracic region. MATERIAL AND METHODS We collected data from patients with Lenke 1 AIS. The following parameters were measured: Cobb angle, side-bending Cobb angle, cervical lordosis (CL), TK, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), the sagittal vertical axis (SVA), the center of a C7 plumb line to the center sacral vertical line (C7-CSVL), correction rate, Ponte osteotomy, flexibility, and screw density. Univariate analysis and multivariate logistic regression analyses were performed. RESULTS Among the 43 cases analyzed, the mean postoperative Cobb angle at the last follow-up, C7-CSVL, SVA, CL, TK, LL, PI, SS, and PT were respectively 21.33±9.47°, 10.41±8.45 mm, 19.68±14.33 mm, 16.19±7.45°, 23.12±7.45°, 50.33±11.37°, 49.70±9.83°, 39.42±8.11°, and 10.16±6.63°. Univariate analysis suggested that preoperative TK, preoperative LL, and Ponte osteotomy were statistically significant (P<0.05), and multivariate analysis suggested that preoperative LL and Ponte osteotomy were statistically significant (P<0.05). CONCLUSIONS The results of this study demonstrated that preoperative TK, preoperative LL, and Ponte osteotomy were related factors for maintaining normal TK. Multivariate analysis suggested that preoperative LL and the use of Ponte osteotomy with full-thickness segmental resection of the spinal posterior column resulted in the successful surgical correction of TK in patients with AIS with Lenke type 1 curvature.

Pelvic incidence correlates to sagittal spinal morphology in lenke 5 adolescent idiopathic scoliosis and influences the proximal junctional kyphosis rate after correction surgery

PURPOSE

This study aimed to investigate the relationship between pelvic incidence and sagittal spinal morphology in Lenke 5 adolescent idiopathic scoliosis (AIS) and its impact on the proximal junctional kyphosis rate after surgery.

METHODS

The study enrolled a total of 52 cases of Lenke 5 AIS between September 2009 and December 2018. Sagittal spinal morphological parameters, pelvic incidence (PI) and the proximal junctional angle were measured on full-length spinal standing lateral x-ray films preoperatively, postoperatively and at the final follow-up. Pearson correlation analysis was performed to reveal the relationship between sagittal spinal morphology and PI. Multivariable regression analysis and receiver operating characteristic (ROC) curve analysis were performed to identify the risk factors for proximal junctional kyphosis (PJK).

RESULTS

A correlation was found between PI and sagittal spinal morphological parameters, but not between PI and lumbar lordosis. The PJK rate after surgery was 23% (12/52). PI was revealed as an independent risk factor for proximal junctional kyphosis according to multivariable regression analysis (OR = 0.902, p = 0.049). Both multivariable regression analysis and ROC curve analysis verified that restoring a rational postoperative PI-LL/PLL relationship reduced the rate of PJK, including PI-LL mismatch (OR = 0.743, p = 0.046; cutoff value = - 15.5°), the LL-PI ratio (OR = 5.756, p = 0.021; cutoff value = 1.09), and the PLL-PI ratio (OR = 2.116, p = 0.016; cutoff value = 0.40).

CONCLUSIONS

PI influences sagittal spinal morphology in Lenke 5 AIS, although it does not show an inherent relationship with lumbar lordosis. PI also correlates to the PJK rate after surgery. Restoring an ideal postoperative PI-LL relationship could decrease the PJK rate.

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.

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis

PURPOSE

This article examines if longer posterior spinal fusions with instrumentation (PSFI) into the lumbar spine (L3/4) alter spinopelvic parameters compared with selective fusions to T12/L1/L2 in adolescent idiopathic scoliosis (AIS) patients.

METHODS

We analysed radiographs of 84 AIS patients, 58 (69%) females and 26 (31%) males, who underwent PSFI at an mean age of 15 years ± 2.5 years, range 10 years to 21 years, between 1st January 2007 and 31st December 2014. Radiographic parameters were measured pre- and post-operatively at most recent follow-up (range 2 years to 8.2 years): pelvic incidence (PI), lumbar lordosis (LL, L1-S1 and L4-S1), sagittal vertical alignment (SVA), scoliosis angle and proximal junctional kyphosis (PJK). PI-LL was calculated. Data was analysed using t-tests or Wilcoxon rank-sum tests.

RESULTS

In total, 32 patients underwent a selective fusion with lowest instrumented vertebra (LIV) T12-L2, and 52 patients underwent a fusion with LIV L3-L4. In both groups, scoliosis angle was significantly corrected at follow-up (p < 0.005).Pre-operatively, both groups had similar LL (L1-S1) and PI-LL. Post-operatively, LL increased in the L3-4 fusion group (p < 0.005) but did not change in the selective fusion group (p = 0.116). This change in LL in the L3-4 fusion group affected the post-operative PI-LL (T12-L2 fusion -4.9° versus L3-4 fusion -13.6°, p = 0.002). No differences were seen in PI, SVA or LL L4-S1 between groups. Radiographic PJK occurred in seven of the L3-4 patients with and without PJK (noPJK -8.8° versus PJK -25.8°, p = 0.026).

CONCLUSIONS

In patients who underwent a fusion ending at L3 or L4, LL was increased. This altered the PI-LL relationship, and appeared to increase the risk of PJK.

LEVEL OF EVIDENCE

III.

Improvement of Sleep Quality in Patients With Ankylosing Spondylitis Kyphosis After Corrective Surgery

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study is to investigate the changes in sleep quality in patients surgically treated for kyphosis due to ankylosing spondylitis (AS) and the correlation between these changes and spinal sagittal realignment.

SUMMARY OF BACKGROUND DATA

Sleep problems are prevalent in AS patients. However, little attention has been paid to the sleep quality in patients with AS kyphosis and the effect of surgical intervention on sleep quality.

METHODS

We have retrospectively reviewed 62 patients with AS-induced thoracolumbar kyphosis who underwent surgically treatment from October 2012 to November 2016. Sleep quality was evaluated by the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Preoperative and postoperative radiological characteristics and supine function were documented. We compared the above-mentioned parameters pre- and 24 months postoperatively and analyzed the correlation of the changes in the PSQI with the changes in radiological characteristics.

RESULTS

Fifity-one patients (82%) classified as poor sleepers preoperatively. In addition to use of sleeping medication, each domain of the PSQI and the total PSQI were increased postoperatively. Improved sleep quality was correlated with changes in spinal sagittal characteristics, among which the lumbar lordosis (LL) and the chin-brow vertical angle (CBVA) were the independent correlation factors. The number of patients with supine dysfunction decreased from 89% to 15% after surgery. Significant differences were identified in the PSQI scores between the patients with and without supine dysfunction either pre- or postoperatively.

CONCLUSION

Surgical correction of spinal deformity may improve sleep quality and supine function in patients with AS. Spinal sagittal realignment may be correlated with the improvement of sleep quality.

LEVEL OF EVIDENCE

4.

The effects of bracing on sagittal spinopelvic parameters and Cobb angle in adolescents with idiopathic scoliosis: A before-after clinical study

Objectives

This study aims to evaluate the effects of bracing on the Cobb angle and sagittal spinopelvic parameters in adolescent idiopathic scoliosis (AIS) patients.

Patients and methods

A total of 25 adolescents (2 males, 23 females; mean age 12.7±1.6; range, 10-15 years) with AIS who received bracing between January 2000 and June 2017 were retrospectively analyzed. The initial and final out-of-brace radiographs of 25 AIS patients were analyzed with regard to the spinopelvic parameters. The pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), Cobb angle, thoracic kyphosis (TK), and lumbar lordosis (LL) were measured.

Results

The mean age at the initiation of bracing was 12.7±1.6 years. The mean initial Cobb angle was 31.8°±5.9°. There were no statistically significant differences between the baseline and the final measurements of the PI, PT, and SS. However, there were statistically significant differences between the baseline and the final measurements of the TK, LL, and Cobb angle. A significant correlation was observed between the PI and Cobb angle and TK and between the LL and SS.

Conclusion

Our study results show significant associations between the sagittal pelvic parameters and the spinal parameters during the brace treatment of adolescents with idiopathic scoliosis.

Analysis of the Change Patterns of Sagittal Alignment Values After Selective Thoracic Fusion in Lenke 1 Adolescent Idiopathic Scoliosis According to Preoperative Thoracic Kyphosis Status

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

The objective of this study was to demonstrate the different change patterns in reciprocal sagittal alignment values after selective thoracic fusion (STF) in Lenke type 1 adolescent idiopathic scoliosis (AIS) according to preoperative thoracic kyphosis (TK).

SUMMARY OF BACKGROUND DATA

Several studies have found significant increase in TK after STF, while other studies have reported decrease in TK postoperatively. Similar inconclusive results on changes in lumbar lordosis (LL) have been reported, showing LL increase, decrease, or no change.

MATERIALS AND METHODS

Ninety-three patients presenting with Lenke type 1 AIS treated by posterior STF with a minimum follow-up of 2 years were included in this study. Using whole spine radiographs, sagittal parameters including TK, LL, and upper lumbar lordosis (ULL) were compared preoperatively and at the last follow-up between a hypokyphosis group (preoperative TK<20 degrees) and a normokyphosis group (preoperative TK≥20 degrees). Health-related quality of life (HRQOL) was assessed using scoliosis research society health-related quality of life-30 (SRS-30) and short from health survey-36 questionnaire at the last visit.

RESULTS

The mean follow-up duration was 74.9 months. In the hypokyphosis group (35 patients), TK, LL, and ULL statistically significantly increased after surgery by mean 7.7, 5.1, and 3.7 degrees (P<0.001, <0.001, and 0.001). In the normokyphosis group (58 patients), these parameters did not show significant changes after STF. Final TK was significantly lower in hypokyphosis group than that in the normokyphosis group (21.2 vs. 30.9 degrees, P<0.001) while final LL did not differ between 2 groups (52.4 vs. 54.6 degrees, P=0.194). HRQOL did not differ significantly between the 2 groups.

CONCLUSIONS

After STF in Lenke 1 AIS, TK, and LL statistically significantly increased through an increase in the mean ULL in the hypokyphosis group while those mean values did not change in the normokyphosis group. Despite the final mean value of the TK in the hypokyphosis group increasing by 7.7 degrees, it was statistically significantly lower than the final mean TK value in the normokyphosis group which did not increase after STF surgery by posterior approach. However, HRQOL showed no significant difference between the 2 groups.

Satisfactory restoration of thoracic kyphosis in Lenke I AIS curves using bilateral vertebral coplanar alignment: an international multicenter experience

STUDY DESIGN

Review of a prospective multicenter registry.

OBJECTIVE

To report the correction of the thoracic sagittal profile in Lenke 1 curves using the bilateral vertebral coplanar alignment (BVCA) maneuver. All-pedicle-screw construtcs provide satisfactory coronal correction but fail to accurately restore the frequent thoracic hypokyphosis of Lenke 1 curves. BVCA is a recently described technique focused on restoration of the normal thoracic kyphosis alignment in AIS patients.

METHODS

A non-consecutive series of 49 AIS patients underwent surgical correction of the deformity by only posterior pedicle screw construct. Coronal and sagittal curve correction was assessed by conventional standing X-rays at preoperative and 2-year follow-up visits. BVCA reduction maneuvers include the correction of the deformity, while descending an implantable rod within slotted tubes attached to the convex side screws. Restoration of physiologic kyphosis is achieved by spreading the distal ends of the tubes at the thoracic spine using different-sized spacers.

RESULTS

Mean preoperative Cobb of the MT curves was 58.4° and was corrected at 70.9%. Preoperative apical vertebral rotation was 18.6° on average and was corrected at 52.9%. T5-T12 kyphosis showed a significant improvement from a mean angle of 18.8º (95% CI 13.3-24.8) to 23.5º (95% CI 20.1-26.1) at 2-year follow-up (a 25% increase) (p = 0.040). Patients with (-) sagittal modifier gained 13.9º on average; those with ( +) modifier decreased 24.0°, and patients with N sagittal modifier remained almost unchanged (2.9°). Differences in the changes of the thoracic sagittal profile between the three groups were statistically significant (p < 0.001). After surgical correction of scoliosis, 87.8% of the patients were considered normokyphotic.

CONCLUSIONS

Clinical results have proven the ability of BVCA to obtain good correction of the deformity in the coronal plane, similar to other methods. However, this technique permits a more relevant restoration of thoracic kyphosis.

Essential lordosis revisited

AIMS

Significant correction of an adolescent idiopathic scoliosis in the coronal plane through a posterior approach is associated with hypokyphosis. Factors such as the magnitude of the preoperative coronal curve, the use of hooks, number of levels fused, preoperative kyphosis, screw density, and rod type have all been implicated. Maintaining the normal thoracic kyphosis is important as hypokyphosis is associated with proximal junctional failure (PJF) and early onset degeneration of the spine. The aim of this study was to determine if coronal correction per se was the most relevant factor in generating hypokyphosis.

METHODS

A total of 95 patients (87% female) with a median age of 14 years were included in our study. Pre- and postoperative radiographs were measured and the operative data including upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), metal density, and thoracic flexibility noted. Further analysis of the post-surgical coronal outcome (group 1 < 60% correction and group 2 ≥ 60%) were studied for their association with the postoperative kyphosis in the sagittal plane using univariate and multivariate logistic regression.

RESULTS

Of the 95 patients, 71.6% (68) had a thoracic correction of > 60%. Most (97.8%) had metal density < 80%, while thoracic flexibility > 50% was found in 30.5% (29). Preoperative hypokyphosis (< 20°) was present in 25.3%. A postoperative thoracic hypokyphosis was four times more likely to occur in patients with thoracic correction ≥ 60% (odds ratio (OR) 4.08; p = 0.005), after adjusting for confounding variables. This association was not affected by metal density, thoracic flexibility, LIV, UIV, age, or sex.

CONCLUSION

Our study supports the 'essential lordosis' hypothesis of Roaf and Dickson, i.e. with a greater ability to translate the apical vertebra towards the midline, there is a commensurate lengthening of the anterior column due to the vertebral wedging. Cite this article: Bone Joint J 2020;102-B(4):513-518.

Deformity correction in thoracic adolescent idiopathic scoliosis

Aims

To compare the rates of sagittal and coronal correction for all-pedicle screw instrumentation and hybrid instrumentation using sublaminar bands in the treatment of thoracic adolescent idiopathic scoliosis (AIS).

Methods

We retrospectively reviewed the medical records of 124 patients who had undergone surgery in two centres for the correction of Lenke 1 or 2 AIS. Radiological evaluation was carried out preoperatively, in the early postoperative phase, and at two-year follow-up. Parameters measured included coronal Cobb angles and thoracic kyphosis. Postoperative alignment was compared after matching the cohorts by preoperative coronal Cobb angle, thoracic kyphosis, lumbar lordosis, and pelvic incidence.

Results

A total of 179 patients were available for analysis. After matching, 124 patients remained (62 in each cohort). Restoration of thoracic kyphosis was significantly better in the sublaminar band group than in the pedicle screw group (from 23.7° to 27.5° to 34.0° versus 23.9° to 18.7° to 21.5°; all p < 0.001). When the preoperative thoracic kyphosis was less than 20°, sublaminar bands achieved a normal postoperative thoracic kyphosis, whereas pedicle screws did not. In the coronal plane, pedicle screws resulted in a significantly better correction than sublaminar bands at final follow-up (73.0% versus 59.7%; p < 0.001).

Conclusion

This is the first study to compare sublaminar bands and pedicle screws for the correction of a thoracic AIS. We have shown that pedicle screws give a good coronal correction which is maintained at two-year follow-up. Conversely, sublaminar bands restore the thoracic kyphosis better while pedicle screws are associated with a flattening of the thoracic spine. In patients with preoperative hypokyphosis, sublaminar bands should be used to restore a proper sagittal profile. Cite this article: Bone Joint J 2020;102-B(3):376–382

Is Any Correlation Present Between the Severity of Syndesmophytes and Spinopelvic and Clinical Parameters in Advanced Ankylosing Spondylitis?

OBJECTIVE

The present study evaluated the severity of syndesmophytes and its correlation with the spinopelvic and clinical outcomes in patients with ankylosing spondylitis (AS).

METHODS

The data from 41 consecutive patients with AS who had undergone pedicle subtraction osteotomy surgery at our institution were reviewed. The computed tomography syndesmophyte score (CTSS), a novel method of evaluating the severity of syndesmophytes, was applied to assess the syndesmophytes of the whole, cervical, thoracic, and lumbar spine. The measured spinopelvic parameters included global kyphosis, sagittal vertical axis, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope. The Oswestry disability index questionnaire, C-reactive protein, and erythrocyte sedimentation rate were used to evaluate the clinical outcome. The Pearson correlation test was performed to identify correlations between syndesmophyte severity and the spinopelvic and clinical parameters.

RESULTS

The Pearson correlation analysis demonstrated that the whole CTSS (WCTSS), cervical CTSS, thoracic CTSS, and lumbar CTSS (LCTSS) correlated significantly with each other (P < 0.05). All the CTSSs correlated positively with age, disease duration, and pelvic tilt (P < 0.05). In addition, both sagittal vertical axis and lumbar lordosis were significantly related to the WCTSS, cervical CTSS, and LCTSS (P < 0.05). The Oswestry disability index correlated negatively with the WCTSS (r = -0.312; P < 0.05), thoracic CTSS (r = -0.314; P < 0.05), and LCTSS (r = -0.343; P < 0.05).

CONCLUSIONS

In advanced AS, old age and a long disease duration are risk factors for the progression of syndesmophytes. The progression of syndesmophytes might contribute to spinal sagittal malalignment. With serious syndesmophytes, pelvic retroversion seems to be the major compensatory mechanism for spinal sagittal malalignment.

Frontal and sagittal imbalance in patients with adolescent idiopathic deformity

The human spinal column underwent many significant changes over the 4.5 million years of our ancestral bipedalism. The main change, however, came with acquiring multiple curvatures in the sagittal plane. This alteration seems to have exposed a weakness in our body's keystone and made us susceptible to thus far unbeknown problems of the spine because it has been noted that idiopathic scoliosis has not been observed in other primates. Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine causing an imbalance of the trunk as it increases in magnitude. A scoliotic curve comprises three components, the coronal, sagittal, and axial so that each curve can affect the global balance of the body differently. Patients with significant scoliotic deformities often find themselves at a biomechanical disadvantage when it comes to energy expenditure and keeping an upright stance. The pioneers of scoliosis research recognized the need for describing and quantifying deformity to better understand it, so they first translated clinical measurements to radiographs and built from there. The development of concepts like defining a curve by its end vertebrae and measuring its magnitude, assessing global spinal balance, describing the stable zone, and pinpointing the stable vertebra all followed suit. The importance of sagittal balance and restoring sagittal parameters during treatment was emphasized. In a quest to bring order to chaos, some tried to classify various scoliotic curve types. These classifications helped steer treatment decisions but were found lacking in many aspects. So far, a widely accepted three-dimensional classification of scoliosis still does not exist. This review aims to provide the reader with an overview of the development of balance and imbalance concepts in scoliosis.

Sublaminar polyester bands for the correction of idiopathic and neuromuscular scoliosis

Recent literature suggests that sublaminar bands (SB) can provide good coronal plane correction, comparable to pedicle screw constructs, as well as good correction in the sagittal plane, even in patients with preoperative hypokyphosis; comparable results have been reported in patients with adolescent idiopathic scoliosis (AIS) and in patients with neuromuscular scoliosis (NMS). Two types of SB constructs can be performed: the band-only construct, indicated for non-ambulatory patients with NMS, and the hybrid construct indicted for ambulatory patients with NMS and for patients with AIS. SB are made of polyester or acrylic material and do provide a safe alternative to sublaminar Luque-type wires (stainless steel) as well as an increased contact area between SB and bone allowing higher corrective forces and reduced laminar fracture risk; the use of SB is not associated with increased risk of neurological injury nor with an increased risk of deep postoperative infection. SB used in a hybrid or in a band-only construct in patients with AIS and NMS, appear to be safe in a trained surgeon hands and can achieve well-balanced spine in both coronal and sagittal planes. This article aimed to provide a review of how SB can restore normal frontal and sagittal spine alignment in patients with AIS and NMS.

PI and T9-SPI: New Predictive Factors for Increased Kyphosis of the Thoracolumbar Junction in Thoracolumbar/Lumbar Adolescent Idiopathic Scoliosis

Objectives: Studies have demonstrated that there is an increased thoracolumbar junction sagittal Cobb angle (TLJS) in thoracolumbar/lumbar adolescent idiopathic scoliosis (AIS) patients. The objectives were to ascertain the correlations between the spinopelvic alignments and TLJS and to explore potential predictive factors for hyperkyphotic TLJS in the sagittal plane in thoracolumbar/lumbar AIS. Methods: A total of 114 AIS patients with thoracolumbar/lumbar curve were included. Cobb angle, apical vertebrae rotation (AVR), thoracic kyphosis (TK), TLJS, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), T1-spinopelvic inclination (T1-SPI), and T9-spinopelvic inclination (T9-SPI) were measured. After patients were organized into two subgroups based on TLJS, all parameters were compared between the two groups. Correlation analysis and multiple linear regression analysis were performed between the radiologic measurements and TLJS in all patients. Results: There was a significant difference between the non-kyphotic group and kyphotic group in mean Nash-Moe grade, TK, T9-SPI, PI, and SS. Correlation analysis showed that LL, PI, and SS were inversely associated with TLJS. TK, T9-SPI, and Nash-Moe grade were positively related to TLJS. The multiple linear regression analysis showed that TLJS could be predicted by the equation TLJS = -2.322 + 5.585 × Nash-Moe grade + 0.687 × T9-SPI - 0.208 × PI, with an adjusted R² of 0.410. Conclusion: TLJS was positively correlated with greater AVR in the coronal plane, greater T9-SPI in the sagittal plane and inversely associated with PI among patients with thoracolumbar/lumbar scoliosis. Spine surgeons should pay more attention to the degree of AVR, T9-SPI, and PI when dealing with thoracolumbar/lumbar scoliosis with thoracolumbar junction kyphosis.

Reciprocal Change in Sagittal Profiles After Adolescent Idiopathic Scoliosis Surgery With Segmental Pedicle Screw Construct: A Full-body X-ray Analysis

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

This radiographic analysis using a full-body x-ray evaluated the ways in which the sagittal profiles of the unfused spinal segments, pelvic, and lower extremities spontaneously change after adolescent idiopathic scoliosis (AIS) surgery with segmental pedicle screw constructs.

SUMMARY OF BACKGROUND DATA

Reciprocal lordotic changes in unfused spinal segments after corrective surgery for AIS have been reported. However, a full-body analysis has not been studied.

METHODS

The sagittal profiles of 51 (age ≤18) patients with AIS undergoing corrective surgery with segmental pedicle screw constructs were investigated. Patients were divided into two groups: group T; selective thoracic fusion and group L; fusion to the low lumbar spine. They were further subcategorized according to preoperative thoracic kyphosis (TK: T5-12): hypokyphotic (TK <20°) and normohyperkyphotic (TK >20°) groups. The postoperative change in the sagittal parameters and the correlation between the instrumented thoracic alignment change (ΔT2-12) and reciprocal changes of unfused segments were analyzed.

RESULTS

At baseline, the entire cohort had a relatively hypokyphotic thoracic spine (TK: 25.5° ± 13.7°), low T1 slope (13.6° ± 7.7°), and kyphotic cervical spine (C2-7 lordosis: 7.7° ± 13.1°). The lower extremities were in neutral alignment overall. Postoperatively, the cervical alignment changed significantly lordotic (average -13.4° increased lordosis) after the adequate preservation of TK (average 17.8° increased kyphosis) in the hypokyphotic group T. Linear correlations were observed between ΔT2-12 and spontaneous reciprocal changes in C2-7 lordosis, lumbar lordosis, and knee flexion angle in group T.

CONCLUSION

The sagittal profiles of patients with AIS can significantly change after adequate restoration of TK which averaged 17.8°, particularly in the cervical spine. Lordotic reciprocal change in the cervical spine as well as increase in lumbar lordosis can occur in a linear correlation after adequate restoration of TK. There were no significant changes that occurred in the pelvis or lower extremities after AIS corrective surgery.

LEVEL OF EVIDENCE

4.

Obesity Is Associated With Increased Thoracic Kyphosis in Adolescent Idiopathic Scoliosis Patients and Nonscoliotic Adolescents

STUDY DESIGN

Retrospective comparative cohort study.

OBJECTIVE

To compare radiographic parameters between adolescents with a greater body mass index (BMI) percentile to underweight individuals.

SUMMARY OF BACKGROUND DATA

Increased BMI percentile has been associated with increased complications after surgical correction of adolescent idiopathic scoliosis (AIS). However, association between BMI percentile and preoperative sagittal plane alignment has not been evaluated. The purpose of this study was to evaluate the effect of BMI percentile on sagittal alignment in AIS patients compared with nonscoliotic adolescents.

METHODS

Posterior-anterior and lateral spinal radiographs of 1,551 AIS patients with a thoracic major curve (Lenke 1-4) and 70 nonscoliotic adolescent patients were compared. BMI percentile was determined based on age and sex, and patients were divided into four categories: underweight (<5th percentile), normal-weight (5th-85th percentile), overweight (85th-95th percentile), and obese (≥95th percentile).

RESULTS

Coronal plane deformity magnitude was not significantly different between the 4 categories of AIS patients (p = .51). Increased BMI percentile was associated with increased thoracic kyphosis globally (T2-T12: p < .005) as well as segmentally (T2-T5: p < .001; T5-T12: p < .001) in patients with AIS. This was also true in obese adolescents without spinal deformity (p < .04). Lumbar lordosis, pelvic incidence, and pelvic tilt were not significantly different between AIS patients in the four BMI percentile categories (p > .07). Pelvic incidence was significantly greater in AIS patients compared with nonscoliotic adolescents (54 ± 13 vs. 46 ± 11; p = .01).

CONCLUSION

Increased BMI percentile is associated with increased thoracic kyphosis in AIS patients and nonscoliotic adolescents. Excess weight may reduce anterior vertebral growth. AIS patients have an increased pelvic incidence compared with nonscoliotic adolescents; however, this variable is not influenced by body mass. These relationships should be taken into account when planning sagittal plane deformity correction or considering neuro axis disorders (also associated with increased kyphosis) in patients with scoliosis.

LEVEL OF EVIDENCE

Level II.

Three-Dimensional Analysis of Initial Brace Correction in the Setting of Adolescent Idiopathic Scoliosis

The three-dimensional nature of adolescent idiopathic scoliosis (AIS) necessitates a tridimensional assessment and management. Bracing constitutes the mainstay conservative treatment for mild adolescent idiopathic scoliosis. In the literature hitherto, there has been uncertainty regarding the behavior of the spine, pelvis, and vertebral orientations in the context of bracing, especially in the transverse plane. This poses a challenge to healthcare providers, patients, and their families, as brace treatment, although not as invasive as surgery, is laden with medical and psychological complications and could be considered traumatizing. Hence, a thorough understanding of initial three-dimensional spinal behavior in the context of bracing is important. The purpose of this retrospective study was to investigate the immediate 3D impact of Chêneau-type brace. Thirty-eight patients with AIS undergoing Chêneau-type bracing were included. Patients were stratified according to their structural curve topography into thoracic, thoracolumbar, and lumbar groups. 3D reconstruction of the spine using a dedicated biplanar stereoradiography software with and without the brace was performed. The examined anthropometric radiographic measures were pre- to in-brace variations and differences of spinopelvic parameters and vertebral orientations in the coronal, sagittal, and transverse planes. The complex impact of the Chêneau-type brace on different curves in three planes was delineated. In the coronal plane, the Cobb angle was significantly decreased in all types of curves, and the coronal tilt correction was concentrated in specific segments. The impact of the brace in this study on the sagittal profile was variable, including the loss of thoracic kyphosis and lumbar lordosis. In the transverse plane, an axial vertebral rotation change and detorsion above the apex occurred in the thoracolumbar curves. The results from this exploratory study could shed some light on the initial 3D spinal behavior in the context of bracing and may be of beneficial for treating physicians and brace makers.

Analysis of Proximal Femoral Parameters in Adolescent Idiopathic Scoliosis

BACKGROUND

Assessment of the proximal femoral parameters in adolescent idiopathic scoliosis using three-dimensional radiological image reconstructions may allow better characterization than conventional techniques.

METHODS

EOS 3D reconstructions of spines and femurs of 320 scoliotic patients (10-18 years old) and 350 control children lacking spinal abnormality were performed and 6 proximal femoral parameters measured.

RESULTS

Individuals with adolescent idiopathic scoliosis showed a small but statistically significant decrease in neck shaft angle (average difference=2.58°) and a higher (0.22°) femoral mechanical axis-femoral shaft angle. When the two sides were compared based on curve direction, greater changes in the neck shaft angle and femoral mechanical axis-femoral shaft angle were found on the side of the convexity.

CONCLUSIONS

Patients with adolescent idiopathic scoliosis were found to have a small but significantly lower neck shaft angle and higher femoral mechanical axis-femoral shaft angle, which related to the curve direction. This is postulated to be due to mechanical compensation for altered balance and centre of gravity associated with a scoliosis deformity, although the observed difference likely has negligible clinical effect.

Preoperative Sagittal Spinal Profile of Adolescent Idiopathic Scoliosis Lenke Types and Non-Scoliotic Adolescents: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

This study aims to determine the differences in sagittal spinopelvic parameters between adolescent idiopathic scoliosis (AIS) Lenke types and non-scoliotic controls through a systematic review and meta-analysis of the available literature.

SUMMARY OF BACKGROUND DATA

AIS classification mainly focuses on frontal curve differences; however, the variations in the sagittal spinopelvic alignment in the current classification system is not fully established.

METHODS

Following preferred reporting items for systematic reviews and meta-analyses guidelines, searches were performed for sagittal spinal and pelvic parameters of Lenke types and non-scoliotic controls in PubMed, Scopus, EMBASE, and Cochrane databases. Selection criteria were: (1) age range 10 to 21 years; (2) Lenke types 1-6 (for AIS group) or non-scoliotic adolescents (for the control group); (3) preoperative data for T5-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and sagittal vertical axis (SVA). (4) Written in English language. PI-LL mismatch was calculated from the weighted average of PI and LL. Publication bias between studies and within studies quality were assessed. A meta-regression compared each measured variable between groups. Thoracic (Lenke1 and 2) and thoracolumbar/lumbar (Lenke 5 and 6) scoliosis were combined and statistically compared with the control group.

RESULTS

Meta-analysis, including 81 AIS and 18 control studies, showed no significant differences in sagittal parameters between Lenke types and controls for LL, PI, PI-LL mismatch, SS, and SVA (P > 0.05). Publication bias was significant in Lenke 1 TK, Control LL, and Lenke 1, and 5 SVA. Stratification based on deformity region (thoracic vs. thoracolumbar/lumbar) showed no significant differences in sagittal spinopelvic parameters (P > 0.05).

CONCLUSION

No definitive difference was found between non-scoliotic adolescents and Lenke types in sagittal spinal and pelvic parameters. Future studies on developing a sagittal classification specific to AIS patients with a goal to improve surgical planning and outcome prediction are highly encouraged.

LEVEL OF EVIDENCE

4.

The Link Between the 3D Spino-pelvic Alignment and Vertebral Body morphology in Adolescent Idiopathic Scoliosis

BACKGROUND

Vertebral anterior overgrowth has been suggested as part of the etio-pathogenesis of adolescent idiopathic scoliosis (AIS). However, the link between 3D spinopelvic alignment and the vertebral anteroposterior height asymmetry in different scoliotic curves types and whether it deviates from the non-scoliotic controls, has not been studied.

PURPOSE

We aimed to retrospectively describe the link between the anteroposterior vertebral height differences (ΔAPVH) measured in the true sagittal plane of each vertebra and the spinopelvic parameters in three anatomical planes.

METHODS

30 AIS cases with primary thoracic curves, 28 with thoracolumbar/lumbar curves, and 20 non-scoliotic controls were included. All subjects had 3D reconstruction of the spine, generated from low-dose upright stereoradiography images. Pelvic incidence (PI), thoracic and lumbar coronal and sagittal curve measurements, and vertebral axial rotation were measured. The association between the spinopelvic parameters and ΔAPVH were compared between the two AIS and control groups.

RESULTS

ΔAPVH at the apex of the curve was significantly different between the two AIS groups, as well as between both AIS groups and the controls and was related to the vertebral apical rotation (p < 0.05). Kyphosis and lordosis measurements were significantly related to the sum of the ΔAPVH in thoracic and lumbar regions respectively in AIS group but not in non-scoliotic controls (p < 0.05).

CONCLUSIONS

The ΔAPVH depended on the scoliotic curve type and was significantly different from the controls only at the apical levels. Morphological changes in the scoliotic vertebrae, measured as anterior-posterior differences in the vertebral height, are related to the sagittal spinal profile suggesting the morphology of the vertebra contributes to the sagittal curvatures of the spine in AIS; nonetheless, such relationship between the vertebral morphology and the sagittal profile was not evident in non-scoliotic controls.

The 3D Sagittal Profile of Thoracic Versus Lumbar Major Curves in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective.

OBJECTIVE

To compare the 3D sagittal profile of patients with main thoracic or thoracolumbar/lumbar adolescent idiopathic scoliosis (AIS) to a normal cohort.

SUMMARY OF BACKGROUND INFORMATION

Thoracic AIS is often associated with a loss of kyphosis. Classically, this measure has been made in 2D, which may underestimate the true sagittal deformity.

METHODS

Biplanar upright radiographs were obtained on 152 primary thoracic (TH: Lenke 1-4), 50 primary thoracolumbar/lumbar (TL/L: Lenke 5-6) curves, and 89 normal controls (NC). 3D spinal reconstructions were created using sterEOS software. MATLAB code was used to create segmental measurements of kyphosis/lordosis for each vertebral and disc segment from T1 to S1 in the local coordinate system of each motion segment. Comparisons were made between groups for the 3D summed segmental measures (T1-T5, T5-T12, T12-S1), pelvic incidence, sacral slope, and pelvic tilt.

RESULTS

Mean 2D Cobb was 57°±12° (range 40°-115°) for TH curves and 52°±9° (range 37°-75°) for TL/L curves. Significant differences in 3D sagittal measures were found between the 3 groups. Post hoc tests revealed significant differences at T1-T5, TH<NC, and TL/L<NC. All groups differed from each other from T5-T12, with the least kyphosis in TH curves. T12-S1 lordosis was significantly greater in TH and TL/L curves compared with NC. Lumbar lordosis extended proximally an average of one segment in AIS compared to normal spines (T11 vs T12). Pelvic incidence, sacral slope, and pelvic tilt were significantly greater for TH curves compared to NC.

CONCLUSIONS

There is a substantial average loss of thoracic kyphosis (∼15°-25°) for both primary thoracic and primary thoracolumbar/lumbar AIS curves compared to normal adolescents. Three-dimensional assessment of scoliosis allows the "true" deformity to be measured by correcting for error due to out-of-plane measurement associated with conventional 2D measurements.

LEVEL OF EVIDENCE

Level II, prognostic.

[The disputes in the radiographic measurements of sagittal balance and how to deal with them]

Objective

To review the process of radiographic measurements of sagittal balance and offer reference for the clinical practice.

Methods

The related literature of spino-pelvic sagittal parameters and their clinical application was reviewed and analyzed from the aspects such as the clinical application, the advantages and disadvantages, and how to use them effectively.

Results

All parameters have their advantages and disadvantages, and they are influenced by age and race. Sagittal vertical axis can only reflect the global balance, and T 1 pelvic angle which accounts for both spinal inclination and pelvic tilt can't be controlled in the surgery. The correction goal for western people may be not suitable for Chinese.

Conclusion

The parameters should be used wisely when evaluating the sagittal balance, the global balance and local balance should be considered together and the different groups of people need different correction goals.

Sagittal Profile Response of Cervical Spine After Posterior Correction in Thoracic and Lumbar Adolescent Idiopathic Scoliosis: Correlation with Thoracic Kyphosis?

OBJECTIVE

To analyze postoperative changes in cervical alignment in patients with adolescent idiopathic scoliosis (AIS) with different curve patterns.

METHODS

Radiographic data were retrospectively reviewed in 43 patients with AIS with right thoracic major curve versus 39 with major lumbar curve with a minimum of 2 years' follow-up. Radiographic parameters analyzed in this study included cervical sagittal parameters (cervical lordosis [CL], T1 slope, T1 slope minus C2-C7 lordosis, T1-spine, T1 pelvic angle, and C2-C7 sagittal vertical axis) and spinopelvic sagittal parameters obtained from radiographs. Paired t tests were used for comparison with 0.05 as a statistically significant threshold.

RESULTS

At baseline, larger CL (5.69° vs. -5.12°, P = 0.002) and smaller T1 slope minus C2-C7 lordosis (9.26° vs. 17.09°, P = 0.001) was noted in patients with lumbar-curve adolescent idiopathic scoliosis (L-AIS), whereas preoperative thoracic kyphosis (TK) was not different between the 2 groups. When the immediate postoperative sagittal profiles were compared between the 2 groups, larger TK (23.72° vs. 18.86°, P = 0.009) and more obvious CL (7.26° vs. -2.60°, P = 0.001) were noticed in the L-AIS group. During the follow-up, larger TK and CL were still maintained in the L-AIS group. In addition, a significant correlation was found between the improvement of CL and TK restoration in patients with L-AIS (r = -0.473, P = 0.002).

CONCLUSIONS

Correlations between the improvement of CL and TK highlight the importance of restoration of patients with normal TK or AIS. Reciprocal changes in cervical alignment may happen if the TK was also simultaneously restored in patients with AIS. For patients with different curve patterns, the cervical sagittal parameters tend to be similar during follow-up.

Sagittal plane assessment of spino-pelvic complex in a Central European population with adolescent idiopathic scoliosis: a case control study

Background

Scoliosis is a complex three-dimensional deformity. While the frontal profile is well understood, increasing attention has turned to balance in the sagittal plane. The present study evaluated changes in sagittal spino-pelvic parameters in a large Hungarian population with adolescent idiopathic scoliosis.

Methods

EOS 2D/3D images of 458 scoliotic and 69 control cases were analyzed. After performing 3D reconstructions, the sagittal parameters were assessed as a whole and by curve type using independent sample t test and linear regression analysis.

Results

Patients with scoliosis had significantly decreased thoracic kyphosis (p < 0.001) with values T1-T12, 34.1 ± 17.1^o vs. 43.4 ± 12.7^o in control; T4-T12, 27.1 ± 18.8^o vs. 37.7 ± 15.1^o in control; and T5-T12, 24.9 ± 15.8^o vs. 32.9 ± 15.0^o in control. Changes in thoracic kyphosis correlated with magnitude of the Cobb angle (p < 0.001). No significant change was found in lumbar lordosis and the pelvic parameters. After substratification according to the Lenke classification and individually evaluating subgroups, results were similar with a significant decrease in only the thoracic kyphosis. A strong correlation was seen between sacral slope, pelvic incidence, and lumbar lordosis, and between pelvic version and thoracic kyphosis in control and scoliotic groups, whereas pelvic incidence was also seen to be correlated with thoracic kyphosis in scoliosis patients.

Conclusion

Adolescent idiopathic scoliosis patients showed a significant decrease in thoracic kyphosis, and the magnitude of the decrease was directly related to the Cobb angle. Changes in pelvic incidence were minimal but were also significantly correlated with thoracic changes. Changes were similar though not identical to those seen in other Caucasian studies and differed from those in other ethnicities. Scoliotic curves and their effect on pelvic balance must still be regarded as individual to each patient, necessitating individual assessment, although changes perhaps can be predicted by patient ethnicity.

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.

Influence of Distal Fusion Level on Sagittal Spinopelvic and Spinal Parameters in the Surgical Management of Adolescent Idiopathic Scoliosis

Study Design

Retrospective analysis of adolescent idiopathic scoliosis.

Purpose

This study aimed to investigate the influence of distinct distal fusion levels on spinopelvic parameters in patients with adolescent idiopathic scoliosis (AIS) who underwent posterior instrumentation and fusion surgery.

Overview of Literature

The distal fusion level selection in treatment of AIS is the one of milestone to effect on surgical outcome. Most of the paper focused on the coronal deformity correction and balance. The literature have lack of knowledge about spinopelvic changing after surgical treatment and the relation with distal fusion level. We evaluate the spinopelvic and pelvic parameter alteration after fusion surgery in treatment of AIS.

Methods

A total of 100 patients with AIS (88 females and 12 males) were retrospectively reviewed. Patients were assigned into the following three groups according to the distal fusion level: lumbar 2 (L2), lumbar 3 (L3), and lumbar 4 (L4). Using a lateral plane radiograph of the whole spine, spinopelvic angular parameters such as thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were radiologically assessed.

Results

The mean age was 15±2.4 years, and the mean follow-up period was 24.27±11.69 months. Regarding the lowest instrumented vertebra, patients were categorized as follows: 30 patients in L2 (group 1), 40 patients in L3 (group 2), and 30 patients in L4 (group 3). TK decreased from 36.60±13.30 degrees preoperatively to 26.00±7.3 degrees postoperatively in each group (p=0.001). LL decreased from 52.8±9.4 degrees preoperatively to 44.30±7.50 degrees postoperatively (p=0.001). Although PI showed no difference preoperatively among the groups, it was statistically higher postoperatively in group 3 than in the other groups (p<0.05). In addition, in group 2, PI decreased from 50.60±8.74 degrees preoperatively to 48.00±6.84 degrees postoperatively (p=0.027). SS decreased from 35.20±6.40 degrees preoperatively to 33.40±5.80 degrees postoperatively (p=0.08, p>0.05). However, mean SS was significantly higher in group 3 (p=0.042, p<0.05). PT decreased from 15.50±7.90 degrees preoperatively to 15.2±7.10 degrees postoperatively. The positive relationship (28.5%) between LL and PI measurements was statistically significant (r=0.285; p=0.004, p<0.01). Furthermore, the positive relationship (36.5%) between LL and SS measurements was statistically significant (r=0.365; p=0.001, p<0.01).

Conclusions

When the distal instrumentation level in AIS surgery is below L3, a significant change in PT and SS (pelvic parameters) is anticipated.

How does the sagittal spinal balance of the scoliotic population deviate from the asymptomatic population?

Background

Previously, the sagittal spinal balance in both asymptomatic and scoliotic Caucasian people has been characterized and compared. Very recently, the sagittal spino-pelvic parameters among asymptomatic Chinese adults have been studied, and the results were compared with Caucasian adults, indicating that a difference did exist. Unfortunately, the distribution of sagittal standing posture patterns among the Chinese population has not been characterized in either asymptomatic or scoliotic groups.

Methods

We conducted a radiographic comparison study to define the deviation of sagittal balance in scoliotic patients from that of an asymptomatic population. A total of 126 asymptomatic and 117 idiopathic scoliotic (IS) young adults were recruited. Radiographic data from each subject were reviewed, and sagittal spinopelvic parameters were measured. The Roussouly type was then determined, as well as the relative position of the C7 plumbline with respect to the sacrum and hip axis. Comparison analyses were undertaken between the two different groups.

Results

The IS group had a larger pelvic incidence, pelvic tilt and sacral slope, but a smaller spinal tilt than the asymptomatic group (P < 0.05), while other sagittal parameters were similar. The distribution of Roussouly types was similar between the asymptomatic and IS groups, of which 49.2% and 45.3% belonged to Roussouly Type 3, respectively. Asymptomatic males and females had a similar distribution, which was different between the two genders in the IS group (P < 0.05), with more females possessing a neutral sagittal standing posture. In addition, more IS subjects had forward displacement of the C7 plumbline than asymptomatic ones (P < 0.05), while there was no difference between the two genders in either group.

Conclusions

Although sagittal pelvic parameters were greater in the IS population, their sagittal spinal balance was maintained and there was no sagittal standing posture pattern correlated with IS. The occurrence of anterior displacement of the C7 plumbline was more common in IS patients than asymptomatic adults, but did not appear to be correlated with gender in both populations.

2016 SOSORT guidelines: orthopaedic and rehabilitation treatment of idiopathic scoliosis during growth

BACKGROUND

The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) produced its first guidelines in 2005 and renewed them in 2011. Recently published high-quality clinical trials on the effect of conservative treatment approaches (braces and exercises) for idiopathic scoliosis prompted us to update the last guidelines' version. The objective was to align the guidelines with the new scientific evidence to assure faster knowledge transfer into clinical practice of conservative treatment for idiopathic scoliosis (CTIS).

METHODS

Physicians, researchers and allied health practitioners working in the area of CTIS were involved in the development of the 2016 guidelines. Multiple literature reviews reviewing the evidence on CTIS (assessment, bracing, physiotherapy, physiotherapeutic scoliosis-specific exercises (PSSE) and other CTIS) were conducted. Documents, recommendations and practical approach flow charts were developed using a Delphi procedure. The process was completed with the Consensus Session held during the first combined SOSORT/IRSSD Meeting held in Banff, Canada, in May 2016.

RESULTS

The contents of the new 2016 guidelines include the following: background on idiopathic scoliosis, description of CTIS approaches for various populations with flow-charts for clinical practice, as well as literature reviews and recommendations on assessment, bracing, PSSE and other CTIS. The present guidelines include a total of 68 recommendations divided into following topics: bracing (n = 25), PSSE to prevent scoliosis progression during growth (n = 12), PSSE during brace treatment and surgical therapy (n = 6), other conservative treatments (n = 2), respiratory function and exercises (n = 3), general sport activities (n = 6); and assessment (n = 14). According to the agreed strength and level of evidence rating scale, there were 2 recommendations on bracing and 1 recommendation on PSSE that reached level of recommendation "I" and level of evidence "II". Three recommendations reached strength of recommendation A based on the level of evidence I (2 for bracing and one for assessment); 39 recommendations reached strength of recommendation B (20 for bracing, 13 for PSSE, and 6 for assessment).The number of paper for each level of evidence for each treatment is shown in Table 8.

CONCLUSION

The 2016 SOSORT guidelines were developed based on the current evidence on CTIS. Over the last 5 years, high-quality evidence has started to emerge, particularly in the areas of efficacy of bracing (one large multicentre trial) and PSSE (three single-centre randomized controlled trials). Several grade A recommendations were presented. Despite the growing high-quality evidence, the heterogeneity of the study protocols limits generalizability of the recommendations. There is a need for standardization of research methods of conservative treatment effectiveness, as recognized by SOSORT and the Scoliosis Research Society (SRS) non-operative management Committee.

Predictors of ultimate postoperative cervical sagittal alignment in main thoracic adolescent idiopathic scoliosis: A long-term follow-up study

This is a retrospective study. The aim of this study was to access sagittal compensatory mechanism of the cervical spine in thoracic adolescent idiopathic scoliosis (T-AIS) before and after posterior spinal fusion and to identify preoperative or immediate postoperative radiographic parameters that can predict the ultimate cervical sagittal alignment (CSA) after long-term follow-up.A retrospective study was performed on 44 T-AIS patients treated with posterior spinal fusion and with at least 5 years of follow-up. Preoperative, immediate postoperative and latest follow-up radiographs were reviewed measuring cervical lordosis (CL), cervical sagittal vertical axis (CSVA), upper thoracic kyphosis (UTK), main thoracic kyphosis (MTK), global thoracic kyphosis (GTK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Pearson correlation analysis, stepwise multilinear regression analysis, and receiver operator characteristic (ROC) curve were performed to define the relationship between ultimate CL and preoperative or immediate postoperative radiographic parameters.CL significantly improved from 6.6 ± 8.8 degree kyphosis preoperatively to 3.8 ± 8.7 degree kyphosis immediate postoperatively and to 0.5 ± 7.3 degree lordosis at the latest follow-up. Pre- and postoperative CSVA showed no significant difference. Pearson correlation coefficient test showed that CL was only correlated to T1 slope and UTK before surgery, whereas it was correlated to T1 slope, UTK, and GTK after surgery. The following equation was developed to estimate the ultimate CL: ultimate CL = -2.792 + 0.510 × Preop CL + 0.531 × Postop T1 slope. Furthermore, ROC curve showed that preoperative CL ≥-4.5 degree was strongly predictive and postoperative T1 slope ≥11.3 degree was moderately predictive of lordotic cervical spine after long-term follow-up.For T-AIS patients, CL significantly increased after surgery with the restoration of the global and regional sagittal profile. The sagittal compensatory mechanism of the cervical spine before surgery is different from that after surgery. In these patients, preoperative CL and immediate postoperative T1 slope could be predictors of the ultimate CSA after long-term follow-up.

THE ETIOLOGIC RELEVANCE OF 3-D PATHOANATOMY OF ADOLESCENT IDIOPATHIC SCOLIOSIS

ABSTRACT Despite many years of dedicated research into the etiopathogenesis of adolescent idiopathic scoliosis, there is still no single distinct cause for this puzzling condition. In this overview, we attempt to link knowledge on the complex three-dimensional pathoanatomy of AIS, based on our ongoing research in this field, with etiopathogenic questions. Evidence from multiple recent cross-sectional imaging studies is provided that supports the hypothesis that AIS has an intrinsic biomechanical basis: an imbalance between the biomechanical loading of the upright human spine due to its unique sagittal configuration on the one hand, and the body’s compensating mechanisms on the other. The question that remains in the etiology of AIS, and the focus of our ongoing research, is to determine what causes or induces this imbalance.

Radiographic and Functional Outcome in Adolescent Idiopathic Scoliosis Operated With Hook/Hybrid Versus All-Pedicle Screw Instrumentation-A Retrospective Study in 149 Patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare radiographic outcome and health-related quality of life in patients with adolescent idiopathic scoliosis (AIS) treated with hook/hybrid (H/H) or all-pedicle screw (PS) instrumentation.

SUMMARY OF BACKGROUND DATA

PS instrumentation has largely replaced H/H in the surgical treatment of AIS but whether a normalized sagittal profile can be obtained with the PS construct is still debated. Additionally, comparative studies assessing HRQL and surgical complications are needed.

METHODS

Two consecutive series of surgically treated AIS patients were included. Surgical treatment consisted of H/H or low-profile all-PS instrumentation. Radiographic and clinical follow-up, including SRS-22r questionnaires, was performed a minimum of two years postoperatively.

RESULTS

There were 85 and 64 patients in the H/H and PS group, respectively. The groups did not differ on baseline parameters apart from a lower flexibility in the H/H group (34% ± 14% vs. 39% ± 14% in the PS group, p = .026). Mean curve correction at final follow-up was 31% ± 13% versus 49% ± 12% in the H/H and PS group, respectively (p < .001), and mean loss of correction was 7° versus 4° (p < .001). The Cincinnati correction index was significantly higher in the PS group at final follow-up (p < .001). Postoperative thoracic kyphosis was significantly higher in the H/H group (27° ± 11° vs. 22° ± 11° in the PS group) with a mean change in kyphosis of 3° ± 9° versus -3° ± 12° in the H/H and PS group, respectively. SRS-22 scores did not differ between the two groups (p > .090), and the reoperation rate at final follow-up was 9% in the H/H group and 6% in the PS group (p = .556).

CONCLUSIONS

In a large consecutive cohort of AIS patients followed for a minimum of two years, we found a significantly better curve correction and less loss of correction with PS instrumentation compared to H/H. There was no significant difference in SRS-22r scores at final follow-up.

LEVEL OF EVIDENCE

Level III.

Analysing the change of sagittal balance in patients with Lenke 5 idiopathic scoliosis

Objective

The aim of this study was to evaluate preoperative and postoperative spinopelvic parameters and the influence of lowest instrumented vertebrae on sagittal parameters in Lenke 5 Adolescent Idiopathic Scoliosis (AIS) patients.

Methods

A total of 42 patients (37 females, 5 males; mean age: 16.71 ± 3.46 years) were included in the study. Preoperative and postoperative last follow up lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), pelvic incidence (PI) and sacral slope (SS) angles measured. By stopped fusion in L3, L4 or L5 we divided the group into three parts.

Results

Mean follow-up was 43 months. Preoperatively, the mean TK and LL were 36.8° and 55.3°. At the last follow up, the mean TK and LL were 27.1° and 49.0° degrees, respectively. Preoperatively, the mean PI, PT and SS were 53.3°, 16.1° and 37.4° degrees. At the last follow up, the mean PI, PT and SS were 52.7°, 19.9° and 33.0° respectively. Significant differences were observed for SS (p = 0.003), TK (p = 0.004), LL (p = 0.012) and PT (p = 0.013) postoperatively for all patients. According the L3 and L4 groups there is significant difference in SS, LL (p = 0.013) and PT (p = 0.018) which means a significant decrease occurs in SS and LL when the distal fusion level changes from L3 to L4 but significant increase in PT in L3 group to compensate spinopelvic change after surgery.

Conclusion

The selection of more distal level for fusion adversely affects the compensation mechanisms of sagittal balance in Lenke 5 AIS patients.

Level of Evidence

Level IV, Therapeutic study.