Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)

Spinal axial torque assessment after surgical correction in adolescent idiopathic scoliosis: a new approach to 3D barycentremetry and mass distribution based on biplanar radiographs

PURPOSE

Barycentremetry in adolescent idiopathic scoliosis (AIS) allows the distribution of masses and their loading of the spine to be studied. In particular, the axial torque on the spine has been studied in AIS, but not after surgical correction. Spinal axial torque was studied in AIS before and after surgery.

METHODS

All AIS (Lenke 1 and 3) who underwent posterior spinal fusion surgery at our center in 2019 were included retrospectively. AIS underwent frontal and sagittal biplanar radiographs in the free-standing position before surgery, 4 months after surgery, and at the last follow-up. Their spine and external envelope were reconstructed with validated methods. Spinal axial torque at the apex and the upper and lower end vertebra was calculated. Finally, the preoperative and postoperative values were compared to a previously published reference corridor for asymptomatic subjects.

RESULTS

Twenty-nine patients were included (54 ± 11° Cobb angle, 15 ± 2 years old at surgery). The surgical procedure decreased the Cobb angle by 36° ± 11° and decreased the spinal axial torque at the upper end vertebra by 2.5 N/m (95% CI = [1.9; 3]; p < 0.001), at the apex by 0.6 N/m (95% CI = [0.4; 1]; p = 0.004), at the lower end vertebra by 2 N/m (95% CI = [1.5; 2.8]; p < 0.001). Compared to 95th percentile of torque, which was previously evaluated in asymptomatic subjects, more than 90% of patients had higher values at the upper and lower end vertebrae before surgery. Postoperatively, 62% of patients still had higher torque at the upper end vertebra than asymptomatic subjects, while only 38% patients showed abnormal values at the lower junction.

CONCLUSION

Results of this study confirm that AIS patients show abnormally high spinal axial torque, especially at the end vertebrae, and that this parameter is normalized postoperatively for only a small number of patients.

Assessment of malalignment at early stage in adolescent idiopathic scoliosis: a longitudinal cohort study

INTRODUCTION

Our objective was to assess abnormalities of the odontoid-hip axis (OD-HA) angle in a mild scoliotic population to determine whether screening for malalignment would help predict the distinction between progressive and stable adolescent idiopathic scoliosis (AIS) at early stage.

MATERIALS AND METHODS

All patients (non-scoliotic and AIS) underwent a biplanar X-ray between 2013 and 2020. In AIS, inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10 years; and no previous treatment. A 3D spine reconstruction was performed, and the OD-HA was computed automatically. A reference corridor for OD-HA values in non-scoliotic subjects was calculated as the range [5th-95th percentiles]. A severity index, helping to distinguish stable and progressive AIS, was calculated and weighted according to the OD-HA value.

RESULTS

Eighty-three non-scoliotic and 205 AIS were included. The mean coronal and sagittal OD-HA angles in the non-scoliotic group were 0.2° and -2.5°, whereas in AIS values were 0.3° and -0.8°, respectively. For coronal and sagittal OD-HA, 27.5% and 26.8% of AIS were outside the reference corridor compared with 10.8% in non-scoliotic (OR = 3.1 and 3). Adding to the severity index a weighting factor based on coronal OD-HA, for thoracic scoliosis, improved the positive predictive value by 9% and the specificity by 13%.

CONCLUSION

Analysis of OD-HA suggests that AIS patients are almost three times more likely to have malalignment compared with a non-scoliotic population. Furthermore, analysis of coronal OD-HA is promising to help the clinician distinguish between stable and progressive thoracic scoliosis.

Narrative Review of Clinical Impact of Head-Hip Offset Following Adult Spinal Deformity Surgery

In adult spinal deformity (ASD) surgery, mechanical failure (MF) has been a significant concern for spine surgeons as well as patients. Despite earnest endeavors to prevent MF, the absence of a definitive consensus persists, owing to the intricate interplay of multifarious factors associated with this complication. Previous approaches centered around global spinal alignment have yielded limited success in entirely forestalling MF. These methodologies, albeit valuable, exhibited limitations by neglecting to encompass global balance and compensatory mechanisms within their purview. In response to this concern, an in-depth comprehension of global balance and compensatory mechanisms emerges as imperative. In this discourse, the center of gravity and the gravity line are gaining attention in recent investigations pertaining to global balance. This narrative review aims to provide an overview of the global balance and a comprehensive understanding of related concepts and knowledge. Moreover, it delves into the clinical ramifications of the contemporary optimal correction paradigm to furnish an encompassing understanding of global balance and the current optimal correction strategies within the context of ASD surgery. By doing so, it endeavors to furnish spine surgeons with a guiding compass, enriching their decision-making process as they navigate the intricate terrain of ASD surgical interventions.

L1-pelvic angle: a convenient measurement to attain optimal deformity correction

PURPOSE

(1) Evaluate the associations between L1-pelvic angle (L1PA) and both sagittal vertical axis (SVA) and T1-pelvic angle (T1PA), and (2) assess the clinical impact of L1PA.

METHODS

A single-institution retrospective cohort study was undertaken for patients undergoing adult spinal deformity (ASD) surgery from 2013 to 2017. Ideal L1PA was defined as (0.5xPelvic Incidence)-21. Pearson correlation was performed to compare L1PA, SVA, and T1PA. Univariate/multivariate regression was performed to assess the effect of L1PA on mechanical complications, controlling for age, BMI, and postoperative pelvic incidence-lumbar lordosis mismatch (PI/LL). Due to the overlapping nature of patients with pseudarthrosis and rod fracture, these patients were analyzed together.

RESULTS

A total of 145 patients were included. Mean preoperative L1PA, SVA, and T1PA were 15.5 ± 8.9°, 90.7 ± 66.8 mm, and 27.1 ± 13.0°, respectively. Mean postoperative L1PA, SVA, and T1PA were 15.0 ± 8.9°, 66.7 ± 52.8 mm, and 22.3 ± 11.1°, respectively. Thirty-six (24.8%) patients achieved ideal L1PA. Though the correlation was modest, preoperative L1PA was linearly correlated with preoperative SVA (r2 = 0.16, r = 0.40, 95%CI = 0.22-0.60, p < 0.001) and T1PA (r2 = 0.41, r = 0.62, 95%CI = 0.46-0.76, p < 0.001). Postoperative L1PA was linearly correlated with postoperative SVA (r2 = 0.12, r = 0.37, 95%CI = 0.18-0.56, p < 0.001) and T1PA (r2 = 0.40, r = 0.62, 95%CI = 0.45-0.74, p < 0.001). Achieving ideal L1PA ± 5° was associated with a decreased risk of rod fracture/pseudarthrosis on univariate and multivariate regression (OR = 0.33, 95%CI = 0.12-0.86, p = 0.024). No association between achieving ideal L1PA and patient-reported outcomes was observed.

CONCLUSION

L1PA was modestly correlated with SVA and T1PA, and achieving ideal L1PA was associated with lower rates of rod fracture/pseudarthrosis. Future studies are warranted to better define the clinical implications of achieving a normal L1PA.

LEVEL OF EVIDENCE

III.

Comparative Efficacy of Clinical Interventions for Sacroiliac Joint Pain: Systematic Review and Network Meta-analysis With Preliminary Design of Treatment Algorithm

OBJECTIVE

We aimed to identify the most effective clinical treatment method for sacroiliac joint (SIJ)-related pain based on the systematic review and network meta-analysis (NMA) to evaluate the comparative efficacy of clinical interventions for sacroiliac joint pain by pooling the randomized controlled trials (RCTs).

METHODS

Our team conducted a systematic review and NMA of RCTs to determine the most effective clinical treatment for SIJ-related pain. We searched the PubMed (MEDLINE), Web of Science, Cochrane Library, and Scopus databases for RCTs until February 2023. The PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines were followed. Pairwise and network meta-analyses were conducted using a random effects model.

RESULTS

Based on the search strategy and inclusion criteria, our systematic review and NMA included 9 randomized studies with 652 participants. Research has mainly focused on various radiofrequency sources, but their number is still low. In the network analysis, according to the NMA and mean ranking probabilities for the improvement of pain intensity (PI) and quality of life (QoL), sacroiliac joint fusion and cooled radiofrequency were associated with high treatment rank for improving PI and QoL in patients with sacroiliac joint pain.

CONCLUSION

This NMA suggest that SIJ fusion and cooled radiofrequency could be potential options for improving the QoL and relieving pain in patients with SIJ-related pain. Comparison studies of outcomes between these 2 procedures with solid methodology and a low risk of bias would be very beneficial to identify the optimal treatment option for this challenging disease.

Reciprocal Changes Following Cervical Realignment Surgery

Over the last few decades, the importance of the sagittal plane and its contour has gained significant recognition. Through full-body stereoradiography, the understanding of compensatory mechanisms, and the concept of global balance and reciprocal change has expanded. There have been a few reports describing how cervical realignment surgery affects global spinal alignment (GSA) and global balance. Despite the research efforts, the concept of reciprocal change and global balance is still perplexing. Understanding the compensatory status and main drivers of deformity in a patient is vital because the compensatory mechanisms may resolve reciprocally following cervical realignment surgery. A meticulous preoperative evaluation of the whole-body alignment, including the pelvis and lower extremities, is paramount to appreciate optimal GSA in the correction of spinal malalignment. This study aims to summarize relevant literature on the reciprocal changes in the whole body caused by cervical realignment surgery and review recent perspectives regarding cervical compensatory mechanisms.

Reciprocal Changes in the Whole-Body Following Realignment Surgery in Adult Spinal Deformity

The idea of the global balance of spine stems from Jean Dubousset, who first introduced the concept of cone of economy. Through the compensatory mechanisms, the human body maintains an upright posture and horizontal gaze in the setting of the spinal malalignment. Compensation takes place not only in the mobile spine segments, but also in the pelvis and lower extremities. Patients with a malalignment exhibit compensatory changes in the cervical hyper-lordosis, posterior pelvic shift, knee/ankle flexion, hip extension, and the pelvic retroversion. The advent of whole-body stereo radiography has yielded an improved understanding of global changes among the patients. Deformity-induced compensatory changes in the sagittal alignment could be resolved reciprocally after the surgical correction of the malalignment. Thoracolumbar realignment surgery restores the pathologic compensatory changes in the unfused spinal segments, pelvis, and the lower extremities. Similarly, reciprocal changes in the thoracolumbar spine may harmonize global sagittal alignment after the cervical reconstruction. This study reviews the compensatory mechanisms and reciprocal changes in global sagittal alignment caused by the surgical correction and highlights, the factors that should be considered while assessing a patient's compensatory status.

Preoperative Malnutrition-Associated Spinal Malalignment with Patient-Reported Outcome Measures in Adult Spinal Deformity Surgery: A 2-Year Follow-Up Study

Introduction

Malnutrition could lead to additional medical complications, and the prognostic nutrition index (PNI) is evaluated to assess the nutritional status of patients. However, the midterm postoperative outcomes of malnutrition in patients with adult spinal deformity (ASD) are unclear. This study aims to investigate postoperative midterm spinal alignment and patients' reported outcome measures (PROMs) in malnourished patients with ASD.

Methods

This study recruited 303 ASD patients who underwent surgery. Adult patients ≥50 years old were categorized into the PNI <50 (L group) and the PNI ≥50 (H group) groups. Demographic data, medical complications, mechanical complications, radiographic parameters, Oswestry Disability Index (ODI), and Scoliosis Research Society-22 (SRS-22) were analyzed.

Results

In this study, 303 patients participated, with 132 and 171 patients in the L and H groups, respectively. Significant differences were noted between the L and H groups in body mass index (22.5 vs. 23.6 kg/m², p=0.011), autoimmune disease (9.8% vs. 2.3%, p=0.005), and total number of medical complications (47.7% vs. 33.3%, p=0.011). The T1 slope was significantly higher in the L group than in the H group preoperatively (36.5 vs. 32.8°, p=0.042). However, no significant differences were noted in mechanical complications, ODI, SRS-22 scores, or radiographic parameters 2 years postoperatively between the L and H groups, except for the sagittal vertical axis (73.1 vs. 55.7 mm, p=0.014).

Conclusions

No significant difference was noted in the incidence of mechanical complications and PROMs 2 years postoperatively. Malnourished status was related to medical complications and global malalignment. However, good surgical outcomes can be expected even for malnourished patients.

Regional Anesthesia for Lumbar Spine Surgery: Can It Be a Standard in the Future?

This paper is an overview of various features of regional anesthesia (RA) and aims to introduce spine surgeons unfamiliar with RA. RA is commonly used for procedures that involve the lower extremities, perineum, pelvic girdle, or lower abdomen. However, general anesthesia (GA) is preferred and most commonly used for lumbar spine surgery. Spinal anesthesia (SA) and epidural anesthesia (EA) are the most commonly used RA methods, and a combined method of SA and EA (CSE). Compared to GA, RA offers numerous benefits including reduced intraoperative blood loss, arterial and venous thrombosis, pulmonary embolism, perioperative cardiac ischemic incidents, renal failure, hypoxic episodes in the postanesthetic care unit, postoperative morbidity and mortality, and decreased incidence of cognitive dysfunction. In spine surgery, RA is associated with lower pain scores, postoperative nausea and vomiting, positioning injuries, shorter anesthesia time, and higher patient satisfaction. Currently, RA is mostly used in short lumbar spine surgeries. However, recent findings illustrate the possibility of applying RA in spinal tumors and spinal fusion. Various researches reveal that SA is an effective alternative to GA with lower minor complications incidence. Comprehensive insight on RA will promote spine surgery under RA, thereby broadening the horizon of spine surgery under RA.