Reliability of a new method for measuring coronal trunk imbalance, the axis-line-angle technique

Bivertebral pedicle-supralaminar autostable claw for proximal fixation of magnetic growing rods in early-onset scoliosis

BACKGROUND

The various methods for the proximal fixation of magnetic growing rods in patients with early-onset scoliosis (EOS) are associated with high rates of mechanical complications related to material failure or proximal junctional kyphosis (PJK). The bivertebral autostable claw (BAC) has been proven reliable in adolescent idiopathic scoliosis but has not been assessed when used with magnetic growing rods. The objective of this study was to describe the operative technique and outcomes of BAC proximal fixation of magnetic growing rods in children with EOS.

HYPOTHESIS

The BAC provides stable and effective proximal fixation in children with early-onset scoliosis.

MATERIAL AND METHODS

This retrospective observational study included 24 patients who had surgery in 2015-2019 for early-onset scoliosis with magnetic growing rod implantation and BAC proximal fixation. Radiological variables were measured in the coronal and sagittal planes before surgery, during the early postoperative period (<3months) and at last follow-up (≥2years).

RESULTS

No neurological complications were recorded. At last follow-up, four patients had radiological PJK, including one patient with clinical PJK due to material failure.

DISCUSSION

BAC proximal fixation is both effective and sufficiently stable (4.2% pull-out) to withstand the forces applied during distraction sessions and daily activities in children with EOS. Moreover, the polyaxial connecting rods ensure better BAC adaptation to the local proximal kyphosis, which is often marked in this population.

CONCLUSION

The BAC is a reliable proximal fixation device that is well-suited to magnetic growing rod fixation in children with EOS.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

Characteristics of the paravertebral muscle in adult degenerative scoliosis with PI-LL match or mismatch and risk factors for PI-LL mismatch

Objective

Pelvic incidence (PI) minus the lumbar lordosis (LL) angle (PI-LL) correlates with function and disability. It is associated with paravertebral muscle (PVM) degeneration and is a valuable tool for surgical planning of adult degenerative scoliosis (ADS). This study aims to explore the characteristics of PVM in ADS with PI-LL match or mismatch and to identify the risk factors for PI-LL mismatch.

Methods

A total of 67 patients with ADS were divided into PI-LL match and mismatch groups. The visual analog scale (VAS), symptom duration, and Oswestry disability index (ODI) were used to assess patients’ clinical symptoms and quality of life. The percentage of fat infiltration area (FIA%) of the multifidus muscle at the L1-S1 disc level was measured by using MRI with Image-J software. Sagittal vertical axis, LL, pelvic tilt (PT), PI, sacral slope, and the asymmetric and average degeneration degree of the multifidus were recorded. Logistic regression analysis was done to identify the risk factors for PI-LL mismatch.

Results

In the PI-LL match and mismatch groups, the average FIA% of the multifidus on the convex side was less than that on the concave side (P &lt; 0.05). There was no statistical difference of asymmetric degeneration degree of the multifidus between the two groups (P &gt; 0.05). In the PI-LL mismatch group, the average degeneration degree of the multifidus, VAS, symptom duration, and ODI were significantly higher than that in the PI-LL match group, respectively (32.22 ± 6.98 vs. 26.28 ± 6.23 (%), 4.33 ± 1.60 vs. 3.52 ± 1.46, 10.81 ± 4.83 vs. 6.58 ± 4.23 (month), 21.06 ± 12.58 vs. 12.97 ± 6.49, P &lt; 0.05). The average degeneration degree of the multifidus muscle was positively correlated with the VAS, symptom duration, and ODI, respectively (r = 0.515, 0.614, and 0.548, P &lt; 0.05). Sagittal plane balance, LL, PT, and the average degeneration degree of the multifidus were the risk factors for PI-LL mismatch (OR: 15.447, 95% CI: 1.274–187.269; OR: 0.001, 95% CI: 0.000–0.099; OR: 107.540, 95% CI: 5.195–2,225.975; OR: 52.531, 95% CI: 1.797–1,535.551, P &lt; 0.05).

Conclusion

The PVM on the concave side was larger than that on the convex side in ADS irrespective of whether PI-LL matched or not. PI-LL mismatch could aggravate this abnormal change, which is an important cause of pain and disability in ADS. Sagittal plane imbalance, decreased LL, higher PT, and larger average degeneration degree of the multifidus were independent risk factors for PI-LL mismatch.

A gait functional classification of adolescent idiopathic scoliosis (AIS) based on spatio-temporal parameters (STP)

BACKGROUND

Therapeutic decisions for patients with adolescent idiopathic scoliosis (AIS) are mostly based on static measurements performed on two-dimensional standing full-spine radiographs. However, the trunk plays an essential role in the human locomotion, and the functional consequences during daily activities of this specific and common spinal deformity are not factored in.

RESEARCH QUESTION

Does patients with AIS have specific gait patterns based on spatio-temporals parameters measurements ?

METHODS

90 AIS patients (aged 10-18 years) with preoperative simplified gait analysis were retrospectively included for analysis between 2017 and 2020. Spatio-temporal parameters (STP) were measured on a 3-m baropodometric gaitway and included the measurement of 15 normalized gait parameters. A hierarchical cluster analysis was performed to identify group of patients based on the similarities of their gait patterns, and functional variables' inter-group differences were also measured. The subject distribution was calculated to identify the structural characteristics of the subjects according to their gait patterns.

RESULTS

Three gait patterns were identified. Cluster 1 (46%) was defined by asymmetry, Cluster 2 (16%) by instability, and Cluster 3 (36%) by variability. Each cluster was significantly different from the other ones on at least 6 different parameters (p < 0.05). Furthermore, each cluster was associated with one type of curve: Lenke 1 for Cluster 1 (57.5%), Lenke 6 for Cluster 2 (40%) and Lenke 5 for Cluster 3 (43.5%).

SIGNIFICANCE

Patients with severe AIS have a dynamic signature during gait identified on STP. Understanding consequences of this deformity on gait may be an interesting avenue to study the pathological mechanisms involved in their dynamic motor organization. Furthermore, these results might also be a first step to study the effectiveness of the different therapies.

Radiophobia Overreaction: College of Chiropractors of British Columbia Revoke Full X-Ray Rights Based on Flawed Study and Radiation Fear-Mongering

Fears over radiation have created irrational pressures to dissuade radiography use within chiropractic. Recently, the regulatory body for chiropractors practicing in British Columbia, Canada, the College of Chiropractors of British Columbia (CCBC), contracted Pierre Côté to review the clinical use of X-rays within the chiropractic profession. A "rapid review" was performed and published quickly and included only 9 papers, the most recent dating from 2005; they concluded, "Given the inherent risks of radiation, we recommend that chiropractors do not use radiographs for the routine and repeat evaluation of the structure and function of the spine." The CCBC then launched an immediate review of the use of X-rays by chiropractors in their jurisdiction. Member and public opinion were gathered but not presented to their members. On February 4, 2021, the College announced amendments to their Professional Conduct Handbook that revoked X-ray rights for routine/repeat assessment and management of patients with spine disorders. Here, we highlight current and historical evidence that substantiates that X-rays are not a public health threat. We also point out critical and insurmountable flaws in the single paper used to support irrational and unscientific policy that discriminates against chiropractors who practice certain forms of evidence-based X-ray-guided methods.

Effects of a Personalized Exercise Rehabilitation Device on Dynamic Postural Balance for Scoliotic Patients: A Feasibility Study

Scoliosis, which is defined as a 3-dimensional spine deformity, may be caused by new-onset degenerative changes that occur well after skeletal maturity and exhibit an asymmetrical postural balance pattern more common to adult deformity than adolescent scoliosis. The aim of this study was to verify whether an exercise program using a personalized exercise rehabilitation device can influence the dynamic postural balance of scoliotic patients. The personalized exercise rehabilitation device was designed to increase the efficacy of 3D postural correction for different curve patterns. 20 subjects were instructed to perform the personalized exercise program that consists of axial elongation, derotation, deflexion, facilitation and stabilization. The results of this study showed that the differences in clinical variables associated with imbalanced posture between the convex and concave side decreased after performing the personalized exercise. Consequentially, a well-designed and manufactured exercise rehabilitation device could be helpful for improving postural balance. Furthermore, the paper suggests that specific exercises using a personalized exercise rehabilitation device can provide the most appropriate exercise therapy and positively correct the asymmetrical postural balance patterns for scoliotic patients.

Bivertebral autostable claws for the proximal fixation in thoracic adolescent idiopathic scoliosis surgery

STUDY DESIGN

Retrospective monocentric study.

OBJECTIVES

To report radiologic outcomes of a consecutive series of AIS patients, operated with a bivertebral autostable claw for the upper instrumentation over a 5-year period. The upper fixation represents the weakest part of long constructs because of local anatomy and the high pull-out forces. Various implants have been proposed, but proximal junctional failures (PJF) and shoulder imbalance still occur with variable incidence. The autostable claw is a new implant, safe, and low profile, combining the mechanical strength of hooks with the initial stability of pedicle screws.

METHODS

All AIS patients operated between January 2010 and July 2015 for a Lenke 1 or 2 curve with the bivertebral autostable claw were included. A minimum 2-year follow-up was required. Full-spine biplanar stereoradiographs were performed preoperatively, within 8 weeks postoperative and at latest examination. Local and global sagittal and coronal parameters were analyzed and complications were reported.

RESULTS

237 patients (191 Lenke 1 and 46 Lenke 2) were included, with a mean follow-up of 4.1 ± 0.6 years. PJF occurred in 2 patients (0.8%), and radiologic PJKs were observed in 8.4% of the series. Shoulder balance was efficiently restored or maintained in 88.2%.

CONCLUSIONS

The bivertebral autostable claw is a safe and robust alternative to pedicle screws for proximal fixation in AIS long constructs. Compression and/or distraction can be applied to level shoulders, and mechanical failures remain rare at 4-year follow-up.

LEVEL OF EVIDENCE

IV.

Scoliosis in Patients With Friedreich Ataxia: Results of a Consecutive Prospective Series

STUDY DESIGN

Prospective monocentric study.

OBJECTIVES

To describe the radiologic characteristics and evolution of spinal shapes in a pediatric cohort of patients with Friedreich ataxia (FA).

SUMMARY OF BACKGROUND DATA

FA is a spinocerebellar degenerative disorder responsible for gait impairment in children and young adults, and several orthopedic deformities can occur during growth, including scoliosis. However, curves' characteristics and their natural evolution have been poorly described, and the subsequent therapeutic management remains controversial.

METHODS

Sixty six FA patients were prospectively included between 2008 and 2017. Clinical, functional, and radiologic records were conducted twice a year. Coronal curve types, segmental measurements, and skeletal maturity were assessed.

RESULTS

A scoliotic deformity was reported in 71% of the patients at a mean age of 11.7 ± 3.1 years. Average follow-up was 6 years, including 75% of patients with closed triradiate cartilage at latest examination. Mean Cobb angle was 34° ± 2°. Main right thoracic curves were the most frequent curves observed (36%), followed by double major (21%), thoracolumbar and left thoracic curves (13%), main lumbar (11%), and long C-shape curves (6%). Hyperkyphosis (>40°) was present in 66%, with an average kyphosis angle of 50° ± 3°, and anterior misalignment (>5°) occurred in 53%. The severity of the Cobb angle was neither correlated to the FA severity scores nor the age at FA diagnosis. An arthrodesis was performed in 9 patients, including 5 patients (45%) who were ambulatory at least 1 year after surgery.

CONCLUSIONS

The prevalence of scoliosis in FA was high (71%), and thoracic hyperkyphosis, with anterior misalignment, was frequently observed, which might be related to the anterior imbalance frequently encountered in patients with an ataxia. Posterior fusion including sacral instrumentation was only performed in nonambulatory patients, and the loss of ambulation was not associated with spinal surgery.

LEVEL OF EVIDENCE

Level IV.

Hip-spine syndrome: cross-sectional-study of spinal alignment in patients with coxalgia

INTRODUCTION:

Patients presenting with hip diseases often have coexisting spine disorders, a condition that is termed "hip-spine syndrome." However, few reports have evaluated total spinal alignments in patients with coxalgia. In this study, we retrospectively examined the relationship between several clinical and x-ray parameters of the hip joints and spinal alignment in patients with coxalgia.

METHODS:

100 patients with coxalgia (24 men, 76 women; average age, 60.0 years; age range, 16-88 years) were included. We retrospectively evaluated the following clinical and x-ray findings of hip joints and total spinal alignment: range of motion (ROM) and pain score components of the Japanese Orthopaedic Association Hip Score; leg length discrepancy (LLD); osteoarthritis (OA) stage of the hip; spinal coronal balance (Cobb angle and C7-central sacral ventral line [CSVL]); and spinal sagittal balance (sagittal vertical axis [SVA], pelvic tilt (PT), and pelvic incidence [PI]).

RESULTS:

Significant positive correlations were detected between C7 - CSVL and LLD ( r = 0.35), whereas a significant negative correlation was found between SVA and hip ROM score ( r = -0.37). A significant positive correlation was also detected between SVA and OA stage of the hip ( r = 0.35).

CONCLUSION:

In the present study, large leg length discrepancy and hip pain may contribute to spinal coronal misalignment. In addition, advanced stage of OA and decreasing ROM of the hip may lead to increased spinal sagittal misalignment. These findings suggest that when evaluating spinal alignment, the progression of OA, LLD, and pain and ROM of the hip joint should be assessed.

Effectiveness of Operative and Nonoperative Care for Adult Spinal Deformity: Systematic Review of the Literature

STUDY DESIGN

Systematic review.

OBJECTIVE

There is a need for synthesizing data on effectiveness of treatments for patients with adult spinal deformity (ASD) due to its increasing prevalence and health care costs for these patients. The objective of this review was to estimate the effectiveness of surgery versus nonoperative care in patients with ASD.

METHODS

A systematic review of articles in published in English using PubMed between 2005 and 2015. Surgical and nonsurgical series that reported baseline and follow-up health-related quality of life measures of patients with ASD with a minimum 2 years of follow-up were selected. Independent extraction of articles by 2 authors using predefined data fields, including risk of bias assessment.

RESULTS

Surgery significantly reduces disability, pain, and improves patients' quality of life. The average postoperative improvement in Oswestry Disability Index was -19.1 (±9.0), Numerical Rating Scale back pain -4.14 (±1.38), Numerical Rating Scale leg pain -3.36 (±1.33), Short-Form Health Survey 36-SF36-Physical Component score 11.2 (±5.07), and Short-Form Health Survey 36-Mental Component score 9.93 (±4.96). The complication rate ranged from 9.52% to 81.52% (mean = 39.62%), and the need for revision surgery ranged from 1.72% to 40.0% (mean = 15.71%). The best existing evidence about nonoperative care of ASD is provided from observational studies with very high risk of bias. Quantitative analyses of nonsurgical cohorts did not demonstrate significant changes in quality of life of patients after 2 years of observation.

CONCLUSIONS

This data may assist clinicians to counsel patients, as well as to inform health care providers and policymakers about what to expect from the treatment for ASD.

What is the optimal cutoff value of the axis-line-angle technique for evaluating trunk imbalance in coronal plane?

BACKGROUND CONTEXT

Accurately evaluating the extent of trunk imbalance in the coronal plane is significant for patients before and after treatment. We preliminarily practiced a new method, axis-line-angle technique (ALAT), for evaluating coronal trunk imbalance with excellent intra-observer and interobserver reliability. Radiologists and surgeons were encouraged to use this method in clinical practice. However, the optimal cutoff value of the ALAT for determination of the extent of coronal trunk imbalance has not been calculated up to now.

PURPOSE

The purpose of this study was to identify the cutoff value of the ALAT that best predicts a positive measurement point to assess coronal balance or imbalance.

STUDY DESIGN/SETTING

A retrospective study at a university affiliated hospital was carried out.

PATIENT SAMPLE

A total of 130 patients with C7-central sacral vertical line (CSVL) >0 mm and aged 10-18 years were recruited in this study from September 2013 to December 2014.

OUTCOME MEASURES

Data were analyzed to determine the optimal cutoff value of the ALAT measurement.

METHODS

The C7-CSVL and ALAT measurements were conducted respectively twice on plain film within a 2-week interval by two radiologists. The optimal cutoff value of the ALAT was analyzed via receiver operating characteristic (ROC) curve. Comparison variables were performed with chi-square test between the C7-CSVL and ALAT measurements for evaluating trunk imbalance. Kappa agreement coefficient method was used to test the intra-observer and interobserver agreement of C7-CSVL and ALAT.

RESULTS

The ROC curve area for the ALAT was 0.82 (95% confidence interval: 0.753-0.894, p<.001). The maximum Youden index was 0.51, and the corresponding cutoff point was 2.59°. No statistical difference was found between the C7-CSVL and ALAT measurements for evaluating trunk imbalance (p>.05). Intra-observer agreement values for the C7-CSVL measurements by observers 1 and 2 were 0.79 and 0.91 (p<.001), respectively, whereas intra-observer agreement values for the ALAT measurements were both 0.89 by observers 1 and 2 (p<.001). The interobserver agreement values for the first and second measurements with the C7-CSVL were 0.78 and 0.85 (p<.001), respectively, whereas the interobserver agreement values for the first and second measurements with the ALAT were 0.91 and 0.88 (p<.001), respectively.

CONCLUSIONS

The newly developed ALAT provided an acceptable optimal cutoff value for evaluating trunk imbalance in the coronal plane with a high level of intra-observer and interobserver agreement, which suggests that the ALAT is suitable for clinical use.