High-Demand Spinal Deformity With Multi-Rod Constructs and Porous Fusion/Fixation Implants: A Finite Element Study

STUDY DESIGN

Basic science (finite element analysis).

OBJECTIVES

Pedicle subtraction osteotomy (PSO) at L5 is an effective treatment for sagittal imbalance, especially in select cases of patients showing kyphosis with the apex at L4-L5 but has been scarcely investigated. The aim of this study was to simulate various "high-demand" instrumentation approaches, including varying numbers of rods and sacropelvic implants, for the stabilization of a PSO at L5.

METHODS

A finite element model of T10-pelvis was modified to simulate posterior fixation with pedicle screws and rods from T10 to S1, alone or in combination with an L5 PSO. Five additional configurations were then created by employing rods and novel porous fusion/fixation implants across the sacroiliac joints, in varying numbers. All models were loaded using pure moments of 7.5 Nm in flexion-extension, lateral bending, and axial rotation.

RESULTS

The osteotomy resulted in a general increase in motion and stresses in posterior rods and S1 pedicle screws. When the number of rods was varied, three- and four-rod configurations were effective in limiting the maximal rod stresses; values approached those of posterior fixation with no osteotomy. Maximum stresses in the accessory rods were similar to or less than those observed in the primary rods. Multiple sacropelvic implants were effective in reducing range of motion, particularly of the SIJ.

CONCLUSIONS

Multi-rod constructs and sacropelvic fixation generally reduced maximal implant stresses and motion in comparison with standard posterior fixation, suggesting a reduced risk of rod breakage and increased joint stability, respectively, when a high-demand construct is utilized for the correction of sagittal imbalance.

Association between the GLP1R A316T Mutation and Adolescent Idiopathic Scoliosis in French Canadian and Italian Cohorts

Studies have revealed anthropometric discrepancies in girls with adolescent idiopathic scoliosis (AIS) compared to non-scoliotic subjects, such as a higher stature, lower weight, and lower body mass index. While the causes are still unknown, it was proposed that metabolic hormones could play a role in AIS pathophysiology. Our objectives were to evaluate the association of GLP1R A316T polymorphism in AIS susceptibility and to study its relationship with disease severity and progression. We performed a retrospective case-control association study with controls and AIS patients from an Italian and French Canadian cohort. The GLP1R rs10305492 polymorphism was genotyped in 1025 subjects (313 non-scoliotic controls and 712 AIS patients) using a validated TaqMan allelic discrimination assay. Associations were evaluated by odds ratio and 95% confidence intervals. In the AIS group, there was a higher frequency of the variant genotype A/G (4.2% vs. 1.3%, OR = 3.40, p = 0.016) and allele A (2.1% vs. 0.6%, OR = 3.35, p = 0.017) than controls. When the AIS group was stratified for severity (≤40° vs. >40°), progression of the disease (progressor vs. non-progressor), curve type, or body mass index, there was no statistically significant difference in the distribution of the polymorphism. Our results support that the GLP1R A316T polymorphism is associated with a higher risk of developing AIS, but without being associated with disease severity and progression.

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.

The influence of peri-operative depressive symptoms on medium-term spine surgery outcome: a prospective study

PURPOSE

To investigate the role of depressive symptoms on clinical outcomes in patients undergoing spinal surgery up to 2-year follow-up.

METHODS

The study used data from an institutional spine surgery registry (January 2016, through March 2022) to identify patients (> 18 years) undergoing spine surgery. Patients with Oswestry Disability Index (ODI) < 20/100 at baseline or undergoing surgery on the cervical spine or for idiopathic spinal deformity and trauma patients were excluded. The patients were divided into two groups based on the pre-operative Mental Component Summary (MCS) score of the SF-36: depression group (MCS ≤ 35) or non-depression group (MCS > 35). The ODI and MCS scores trajectory were wined over the 24-month post-surgery between groups. Additionally, a secondary subgroup analysis was conducted comparing outcomes between those with depressive symptoms (persistent-depression subgroup) and those without depressive symptoms (never-depression subgroup) at 3 months after surgery.

RESULTS

A total of 2164 patients who underwent spine surgery were included. The pre-operative depression group reported higher ODI total scores and lower MCS than the pre-operative non-depression group at all time points (P < 0.001). The persistent-depression subgroup reported higher ODI total scores and lower MCS than the never-depression subgroup at all follow-ups (P < 0.001).

CONCLUSION

Functional disability and mental health status improve in patients with depression symptoms undergoing spinal surgery. Despite this improvement, they do not reach the values of non-depressed subjects. Over the 2-year follow-up time, patients with depression show a different trajectory of ODI and MCS. Caregivers should be aware of these results to counsel patients with depression symptoms.

Stability and Instrumentation Stresses Among Sacropelvic Fixation Techniques With Novel Porous Fusion/Fixation Implants: A Finite Element Study

BACKGROUND

Sacropelvic fixation is frequently combined with thoracolumbar instrumentation for correcting spinal deformities. This study aimed to characterize sacropelvic fixation techniques using novel porous fusion/fixation implants (PFFI).

METHODS

Three T10-pelvis finite element models were created: (1) pedicle screws and rods in T10-S1, PFFI bilaterally in S2 alar-iliac (S2AI) trajectory; (2) fixation in T10-S1, PFFI bilaterally in S2AI trajectory, triangular implants bilaterally above the PFFI in a sacro-alar-iliac trajectory (PFFI-IFSAI); and (3) fixation in T10-S1, PFFI bilaterally in S2AI trajectory, PFFI in sacro-alar-iliac trajectory stacked cephalad to those in S2AI position (2-PFFI). Models were loaded with pure moments of 7.5 Nm in flexion-extension, lateral bending, and axial rotation. Outputs were compared against 2 baseline models: (1) pedicle screws and rods in T10-S1 (PED), and (2) pedicle screws and rods in T10-S1, and S2AI screws.

RESULTS

PFFI and S2AI resulted in similar L5-S1 motion; adding another PFFI per side (2-PFFI) further reduced this motion. Sacroiliac joint (SIJ) motion was also similar between PFFI and S2AI; PFFI-IFSAI and 2-PFFI demonstrated a further reduction in SIJ motion. Additionally, PFFI reduced max stresses on S1 pedicle screws and on implants in the S2AI position.

CONCLUSION

The study shows that supplementing a long construct with PFFI increases the stability of the L5-S1 and SIJ and reduces stresses on the S1 pedicle screws and implants in the S2AI position.

CLINICAL RELEVANCE

The findings suggest a reduced risk of pseudarthrosis at L5-S1 and screw breakage. Clinical studies may be performed to demonstrate applicability to patient outcomes.

LEVEL OF EVIDENCE

Not applicable (basic science study).

Quality Control for Spine Registries: Development and Application of a New Protocol

Registries are gaining importance both in clinical practice and for research purposes. However, quality control is paramount to ensure that data are consistent and reliable. Quality control protocols have been proposed for arthroplasty registries, but these are not directly applicable to the spine setting. This study aims to develop a new quality control protocol for spine registries. Based on the available protocols for arthroplasty registries, a new protocol for spine registries was developed. The items included in the protocol were completeness (yearly enrollment rate and rate of assessment completion), consistency, and internal validity (coherence between registry data and medical records for blood loss, body mass index, and treated levels). All aspects were then applied to the spine registry of the Institution to verify its quality for each of the 5 years in which the registry has been used (2016-2020). Regarding completeness, the yearly enrollment rate ranged from 78 to 86%; the completion of preoperative assessment from 79% to 100%. The yearly consistency rate varied from 83% to 86%. Considering internal validity, the interclass correlation coefficient ranged from 0.1 to 0.8 for blood loss and from 0.3 to 0.9 for body mass index. The coherency for treated levels ranged from 25% to 82%. Overall, all 3 items showed an improvement over time. All 3 analyzed domains showed good to excellent results. The overall quality of the registered data improved over time.

Automatic classification of the vertebral endplate lesions in magnetic resonance imaging by deep learning model

Introduction

A novel classification scheme for endplate lesions, based on T2-weighted images from magnetic resonance imaging (MRI) scan, has been recently introduced and validated. The scheme categorizes intervertebral spaces as "normal," "wavy/irregular," "notched," and "Schmorl's node." These lesions have been associated with spinal pathologies, including disc degeneration and low back pain. The exploitation of an automatic tool for the detection of the lesions would facilitate clinical practice by reducing the workload and the diagnosis time. The present work exploits a deep learning application based on convolutional neural networks to automatically classify the type of lesion.

Methods

T2-weighted MRI scans of the sagittal lumbosacral spine of consecutive patients were retrospectively collected. The middle slice of each scan was manually processed to identify the intervertebral spaces from L1L2 to L5S1, and the corresponding lesion type was labeled. A total of 1,559 gradable discs were obtained, with the following types of distribution: "normal" (567 discs), "wavy/irregular" (485), "notched" (362), and "Schmorl's node" (145). The dataset was divided randomly into a training set and a validation set while preserving the original distribution of lesion types in each set. A pretrained network for image classification was utilized, and fine-tuning was performed using the training set. The retrained net was then applied to the validation set to evaluate the overall accuracy and accuracy for each specific lesion type.

Results

The overall rate of accuracy was found equal to 88%. The accuracy for the specific lesion type was found as follows: 91% (normal), 82% (wavy/irregular), 93% (notched), and 83% (Schmorl's node).

Discussion

The results indicate that the deep learning approach achieved high accuracy for both overall classification and individual lesion types. In clinical applications, this implementation could be employed as part of an automatic detection tool for pathological conditions characterized by the presence of endplate lesions, such as spinal osteochondrosis.

Accuracy of Rod Contouring to Desired Angles With and Without a Template: Implications for Achieving Desired Spinal Alignment and Outcomes

STUDY DESIGN

Biomechanical Study.

OBJECTIVE

The search for optimal spinal alignment has led to the development of sophisticated formulas and software for preoperative planning. However, preoperative plans are not always appropriately executed since rod contouring during surgery is often subjective and estimated by the surgeon. We aimed to assess whether rods contoured to specific angles with a French rod bender using a template guide will be more accurate than rods contoured without a template.

METHODS

Ten experienced spine surgeons were requested to contour two 125 × 5.5 mm Ti64 rods to 40°, 60° and 80° without templates and then 2 more rods using 2D metallic templates with the same angles. Rod angles were then measured for accuracy and compared.

RESULTS

Average angles for rods bent without a template to 40°, 60° and 80° were 60.2°, 78.9° and 97.5°, respectively. Without a template, rods were overbent by a mean of 18.9°. When using templates of 40°, 60° and 80°, mean bend angles were 41.5°, 59.1° and 78.7°, respectively, with an average underbend of 0.2°. Differences between the template and non-template groups for each target angle were all significant (p < 0.001).

CONCLUSIONS

Without the template, surgeons tend to overbend rods compared to the desired angle, while surgeons improved markedly with a template guide. This tendency to overbend could have significant impact on patient outcomes and risk of proximal junctional failure and warrants further research to better enable surgeons to more accurately execute preoperative alignment plans.

Effect of Sacropelvic Hardware on Axis and Center of Rotation of the Sacroiliac Joint: A Finite Element Study

BACKGROUND

The sacroiliac joint (SIJ) transfers the load of the upper body to the lower extremities while allowing a variable physiological movement among individuals. The axis of rotation (AoR) and center of rotation (CoR) of the SIJ can be evaluated to analyze the stability of the SIJ, including when the sacrum is fixed. The purpose of this study was to determine how load intensity affects the SIJ for the intact model and to characterize how sacropelvic fixation performed with different techniques affects this joint.

METHODS

Five T10-pelvis models were used: (1) intact model; (2) pedicle screws and rods in T10-S1; (3)pedicle screws and rods in T10-S1, and bilateral S2 alar-iliac screws (S2AI); (4) pedicle screws and rods in T10-S1, bilateral S2AI screws, and triangular implants inserted bilaterally in a sacral alar-iliac trajectory ; and (5) pedicle screws and rods in T10-S1, bilateral S2AI screws, and 2 bilateral triangular implants inserted in a lateral trajectory. Outputs of these models under flexion-extension were compared: AoR and CoR of the SIJ at incremental steps from 0 to 7.5 Nm for the intact model and AoR and CoR of the SIJ for the instrumented models at 7.5 Nm.

RESULTS

The intact model was validated against an in vivo study by comparing range of motion and displacement of the sacrum. Increasing the load intensity for the intact model led to an increase of the rotation of the sacrum but did not change the CoR. Comparison among the instrumented models showed that sacropelvic fixation techniques reduced the rotation of the sacrum and stabilized the SIJ, in particular with triangular implants.

CONCLUSION

The study outcomes suggest that increasing load intensity increases the rotation of the sacrum but does not influence the CoR, and use of sacropelvic fixation increases the stability of the SIJ, especially when triangular implants are employed.

CLINICAL RELEVANCE

The choice of the instrumentation strategy for sacropelvic fixation affects the stability of the construct in terms of both range of motion and axes of rotation, with direct consequences on the risk of failure and mobilization. Clinical studies should be performed to confirm these biomechanical findings.

Is posteromedial translation with sublaminar bands effective in correcting axial rotation in adolescent idiopathic scoliosis surgery? A 3D reconstruction study

PURPOSE

Hybrid constructs with sublaminar bands have recently regained popularity as an alternative to all-screw construct for correction of adolescent idiopathic scoliosis (AIS). The aim of this study is to evaluate the ability of hybrid constructs with sublaminar bands to achieve a tridimensional correction of the scoliotic deformity. Our hypothesis is that hybrid construct with sublaminar bands are able to achieve a substantial derotation of the apical vertebrae, while preserving the thoracic kyphosis.

METHODS

A prospective evaluation of 50 consecutive cases (41 F, 9 M, mean age 14.7 ± 2 years) of AIS correction with hybrid construct was performed. In all cases, sublaminar bands were used at the apex of the main curve on concave side. All patients underwent pre and postoperative X-rays with EOS System, with full 3D reconstruction. Spinopelvic parameters and axial rotation of the vertebrae were measured pre and postoperatively.

RESULTS

2.7 ± 0.9 mean sublaminar bands were used per patient. Mean correction of deformity was 50 ± 9.5%. on the coronal plane. The mean axial rotation of the apical vertebra went from 18° ± 11.5° preoperatively to 9.4° ± 7.2° postoperatively (p < 0.001) with a mean derotation of 47.7%. Thoracic kyphosis went from 32.1° ± 18° preoperatively to 37.3° ± 13.1° postoperatively (p < 0.05). No intraoperative complications due to sublaminar bands were recorded.

CONCLUSIONS

Hybrid construct with sublaminar band have been showed to be safe and effective in deformity correction and in maintaining or restoring thoracic kyphosis. This study showed that with sublaminar bands applied at the curve apex a substantial derotation of the apical vertebrae can be achieved.

Spinal cord stimulator medullary compression-a very rare SCS complication and surgical treatment

INTRODUCTION

The risk of spinal cord damage after Spinal Cord Stimulator (SCS) implant is a very rare event. In our case report, the patient was affected by a progressively worsening spinal stenosis due to SCS compression.

CASE REPORT

The authors describe a progressive paraparesis in a 58-year-old woman with a long history of back pain and multiple spine surgeries. Computed tomography (CT) outlined vertebral canal stenosis corresponding to an electrode array implanted in T9. A posterior T8-T10 spinal cord decompression with explanation of the SCS device was performed and a partial neurological improvement was observed immediately postoperative.

DISCUSSION

Spinal cord stimulation has been used since 1967 for the treatment of refractory chronic pain, particularly failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS). Still, the mechanism underlying its function is not completely clear. Moreover, complications are mainly related to implant dysfunction and the risk of direct and indirect spinal cord compression is described as exceptional in the literature. Our aim is to describe the case SCS device spinal cord direct compression and its surgical treatment.

Spinal disorders and mastication: the potential relationship between adolescent idiopathic scoliosis and alterations of the chewing patterns

OBJECTIVE

to evaluate mastication in a group of patients with Adolescent Idiopathic Scoliosis (AIS) with a control group, by means of the prevalence of reverse chewing cycles (RCC).

MATERIAL AND METHODS

this study included a group of patients (N=32; F=24; M=8; mean age ± SD = 14±3 years) with a confirmed diagnosis of Adolescent Idiopathic Scoliosis and a group of control subjects (N=32; F=24; M=8; mean age ± SD = 13±6 years) without spinal disorders. Mastication was recorded with both a hard and a soft bolus, following a standardized protocol, and the prevalence of reverse chewing cycles was compared between the groups.

RESULTS

The prevalence of reverse chewing cycles was significantly higher in the Adolescent Idiopathic Scoliosis group, with both a soft and a hard bolus, compared to the control group (p<0,001).

CONCLUSION

the results of this study indicate that the presence of Adolescent Idiopathic Scoliosis influences mastication, i.e. one of the main functions of the stomatognathic system. A multidisciplinary approach to these patients may be relevant in providing the best possible treatment outcomes.

SPINE20 recommendations 2021: spine care for people's health and prosperity

Purpose

The focus of SPINE20 is to develop evidence-based policy recommendations for the G20 countries to work with governments to reduce the burden of spine disease, and disability.

Methods

On September 17–18, 2021, SPINE20 held its annual meeting in Rome, Italy. Prior to the meeting, the SPINE20 created six proposed recommendations. These recommendations were uploaded to the SPINE20 website 10 days before the meeting and opened to the public for comments. The recommendations were discussed at the meeting allowing the participants to object and provide comments.

Results

In total, 27 societies endorsed the following recommendations. SPINE20 calls upon the G20 countries: (1) to expand telehealth for the access to spine care, especially in light of the current situation with COVID-19. (2) To adopt value-based interprofessional spine care as an approach to improve patient outcomes and reduce disability. (3) To facilitate access and invest in the development of a competent rehabilitation workforce to reduce the burden of disability related to spine disorders. (4) To adopt a strategy to promote daily physical activity and exercises among the elderly population to maintain an active and independent life with a healthy spine, particularly after COVID-19 pandemic. (5) To engage in capacity building with emerging countries and underserved communities for the benefit of spine patients. (6) To promote strategies to transfer evidence-based advances into patient benefit through effective implementation processes.

Conclusions

SPINE20’s initiatives will make governments and decision makers aware of efforts to reduce needless suffering from disabling spine pain through education that can be instituted across the globe.

Delayed postoperative cervical spinal cord ischemic lesion after a thoracolumbar fusion for syndromic scoliosis: a case report and systematic review of the literature

INTRODUCTION

We report a case and a literature review of delayed postoperative cervical spinal cord injury after thoraco-lumbar spine surgery.

CASE REPORT

A 13-year-old Prader-Willi Syndrome female was treated by a T3-L5 posterior spine fusion for progressive scoliosis. Intraoperative neuromonitoring and immediate postoperative neurological examination were normal. Sixty hours after surgery, she developed a tetraplegia. The immediate MRI and CT scan of the spine were negative. Two days after, a new MRI revealed an ischemic cervical lesion at the level C5-C6. After 1 week, she gradually improved breathing and motility/sensibility at the extremities. After 4 months of intensive neurologic rehabilitation, the patient improved to ASIA grade D and was discharged. At 1-year follow, the neurologic recovery was nearly completed.

METHODS

We performed a systematic review of the literature through PubMed and Embase database focused on delayed postoperative cervical spinal cord lesion after a thoraco-lumbar fusion for spinal deformity.

RESULTS

Only 14 cases of neurological injuries at levels above the site of surgery have been previously reported and never in Prader Willy Syndrome. All patients were adolescent and 86,7% were females but no specific risk factors were found.

CONCLUSIONS

Delayed postoperative neurological deficit far from the surgical site can be considered a specific subgroup of these rare complication that can occur several hours after spine surgery, regardless of intraoperative complication. Despite the rarity of this complication, clinicians should be aware of it. Perioperative optimization of spinal cord perfusion and close neurological examination in first postoperative days may be helpful to quickly recognize and treat this complication.

Prediction of Long-Term Recovery From Disability Using Hemoglobin-Based Models: Results From a Cohort of 1,392 Patients Undergoing Spine Surgery

Hemoglobin and its associated blood values are important laboratory biomarkers that mirror the strength of constitution of patients undergoing spine surgery. Along with the clinical determinants available during the preadmission visit, it is important to explore their potential for predicting clinical success from the patient's perspective in order to make the pre-admission visit more patient-centered. We analyzed data from 1,392 patients with spine deformity, disc disease, or spondylolisthesis enrolled between 2016 and 2019 in our institutional Spine Registry. Patient-reported outcome measure at 17 months after surgery was referred to the Oswestry disability index. High preoperative hemoglobin was found to be the strongest biochemical determinant of clinical success along with high red blood cells count, while low baseline disability, prolonged hospitalization, and long surgical times were associated with poor recovery. The neural network model of these predictors showed a fair diagnostic performance, having an area under the curve of 0.726 and a sensitivity of 86.79%. However, the specificity of the model was 15.15%, thus providing to be unreliable in forecasting poor patient-reported outcomes. In conclusion, preoperative hemoglobin may be one of the key biomarkers on which to build appropriate predictive models of long-term recovery after spine surgery, but it is necessary to include multidimensional variables in the models to increase the reliability at the patient's level.

Perioperative Anesthesia and Acute Smell Alterations in Spine Surgery: A “Sniffing Impairment” Influencing Refeeding?

Medications for general anesthesia can cause smell alterations after surgery, with inhalation anesthetics being the most acknowledged drugs. However, spine patients have been poorly studied in past investigations and whether these alterations could influence the refeeding remains unclear. This research aims to observe detectable dysosmias after spine surgery, to explore any amplified affection of halogenates (DESflurane and SEVoflurane) against total intravenous anesthesia (TIVA), and to spot potential repercussions on the refeeding. Fifty patients between 50 and 85 years old were recruited before elective spine procedure and tested for odor acuity and discrimination using the Sniffin' Sticks test. The odor abilities were re-assessed within the first 15 h after surgery together with the monitoring of food intakes. The threshold reduced from 4.92 ± 1.61 to 4.81 ± 1.64 (p = 0.237) and the discrimination ability reduced from 10.50 ± 1.83 to 9.52 ± 1.98 (p = 0.0005). Anesthetic-specific analysis showed a significant reduction of both threshold (p = 0.004) and discrimination (p = 0.004) in the SEV group, and a significant reduction of discrimination abilities (p = 0.016) in the DES group. No dysosmias were observed in TIVA patients after surgery. Food intakes were lower in the TIVA group compared to both DES (p = 0.026) and SEV (p = 0.017). The food consumed was not associated with the sniffing impairment but appeared to be inversely associated with the surgical time. These results confirmed the evidence on inhalation anesthetics to cause smell alterations in spine patients. Furthermore, the poor early oral intake after complex procedures suggests that spinal deformity surgery could be a practical challenge to early oral nutrition.

Bacterial adhesion on spinal implants: An in vitro study of "hot spots"

Few studies evaluated bacterial colonization of spinal implants from a "topographic" point of view. This lack of knowledge could hinder the development of more effective strategies in the prevention and treatment of postoperative spinal infections. The aim of this in vitro study was the analysis of the adhesion pattern of sessile cells on conventional spinal implants, to identify "hot spots" on implants where bacterial adhesion could be favored. Clinically relevant Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa isolates were grown on commercially available end product spinal implants. To identify sessile cells attached to implant surfaces, confocal laser scan microscopy was used. Different areas from the spinal instrumentations (both Ti and CoCr) were selected for biofilm quantification. Bacterial biofilm was markedly increased in the cut of the rods, both Ti and CoCr, as the uneven surface deriving from the cut might foster cell adhesion. Though not statistically significant, a difference was observed between the rod and the area of the notch, possibly as a consequence of the smoothening effect deriving from the bending of the rod. Finally, the amount of biofilm produced on cobalt-chromium surfaces was always more significant than that formed on titanium surfaces. This study highlights how bacterial adhesion through biofilm formation is favored on the surfaces of higher irregularity and that staphylococci are able to increase sessile biomass on CoCr surfaces. These preliminary results show how surface modifications on the implants may play a key role in bacterial adhesion, opening an exciting field for future research.

Innovative sacropelvic fixation using iliac screws and triangular titanium implants

PURPOSE

Sacropelvic fixation is frequently used in combination with thoracolumbar instrumentation for the correction of severe spinal deformities. The purpose of this study was to explore the effects of the triangular titanium implants on the iliac screw fixation. Our hypothesis was that the use of triangular titanium implants can increase the stability of the iliac screw fixation.

METHODS

Three T10-pelvis instrumented models were created: pedicle screws and rods in T10-S1, and bilateral iliac screws (IL); posterior fixation and bilateral iliac screws and triangular implants inserted bilaterally in a sacro-alar-iliac trajectory (IL-Tri-SAI); posterior fixation and bilateral iliac screws and two bilateral triangular titanium implants inserted in a lateral trajectory (IL-Tri-Lat). Outputs of these models, such as hardware stresses, were compared against a model with pedicle screws and rods in T10-S1 (PED).

RESULTS

Sacropelvic fixation decreased the L5-S1 motion by 75-90%. The motion of the SIJ was reduced by 55-80% after iliac fixation; the addition of triangular titanium implants further reduced it. IL, IL-Tri-SAI and IL-Tri-Lat demonstrated lower S1 pedicle stresses with respect to PED. Triangular implants had a protective effect on the iliac screw stresses.

CONCLUSION

Sacropelvic fixation decreased L5-S1 range of motion suggesting increased stability of the joint. The combination of triangular titanium implants and iliac screws reduced the residual flexibility of the sacroiliac joint, and resulted in a protective effect on the S1 pedicle screws and iliac screws themselves. Clinical studies may be performed to demonstrate applicability of these FEA results to patient outcomes.

High-Throughput Gene and Protein Analysis Revealed the Response of Disc Cells to Vitamin D, Depending on the VDR FokI Variants

Vitamin D showed a protective effect on intervertebral disc degeneration (IDD) although conflicting evidence is reported. An explanation could be due to the presence of the FokI functional variant in the vitamin D receptor (VDR), observed as associated with spine pathologies. The present study was aimed at investigating—through high-throughput gene and protein analysis—the response of human disc cells to vitamin D, depending on the VDR FokI variants. The presence of FokI VDR polymorphism was determined in disc cells from patients with discopathy. 1,25(OH)₂D₃ was administered to the cells with or without interleukin 1 beta (IL-1β). Microarray, protein arrays, and multiplex protein analysis were performed. In both FokI genotypes (FF and Ff), vitamin D upregulated metabolic genes of collagen. In FF cells, the hormone promoted the matrix proteins synthesis and a downregulation of enzymes involved in matrix catabolism, whereas Ff cells behaved oppositely. In FF cells, inflammation seems to hamper the synthetic activity mediated by vitamin D. Angiogenic markers were upregulated in FF cells, along with hypertrophic markers, some of them upregulated also in Ff cells after vitamin D treatment. Higher inflammatory protein modulation after vitamin D treatment was observed in inflammatory condition. These findings would help to clarify the clinical potential of vitamin D supplementation in patients affected by IDD.

How SARS-CoV-2 Pandemic Changed Traumatology and Hospital Setting: An Analysis of 498 Fractured Patients

Background: SARS-CoV-2 pandemic is one of the biggest challenges for many health systems in the world, making lots of them overwhelmed by the enormous pressure to manage patients. We reported our Institutional Experience, with specific aims to describe the distribution and type of treated injuries, and the organizational setup of our hospital. Methods: Data of fractured patients admitted for surgical treatment in the time frames 9 March 2020–4 May 2020 and 1 March 2019–31 May 2019 were collected and compared. Furthermore, surgery duration and some parameters of effectiveness in health management were compared. Results: A total of 498 patients were included. Mean age significantly lower age in 2019 and femoral fractures were significantly more frequent 2020. Mean surgery time was significantly longer in 2020. Mortality rate difference between the two years was found to be statistically significant. Time interval between diagnosis and surgery and between diagnosis and discharge/decease was significantly lower in 2020. In 2020, no patient admitted with a negative swab turned positive in any of the following tests for SARS-CoV-2. Conclusions: The COVID-19 pandemic has modified the epidemiology of hospitalized patients for traumatic reasons, leading to an increased admission of older patients with femoral fractures. Nevertheless, our institutional experience showed that an efficient change in the hospital organization, with an improvement of several parameters of effectiveness in health management, led to a null infection rate between patients.

SPINE20 A global advocacy group promoting evidence-based spine care of value

PURPOSE

The Global Burden of Diseases (GBD) Studies have estimated that low back pain is one of the costliest ailments worldwide. Subsequent to GBD publications, leadership of the four largest global spine societies agreed to form SPINE20. This article introduces the concept of SPINE20, the recommendations, and the future of this global advocacy group linked to G20 annual summits.

METHODS

The founders of SPINE20 advocacy group coordinated with G20 Saudi Arabia to conduct the SPINE20 summit in 2020. The summit was intended to promote evidence-based recommendations to use the most reliable information from high-level research. Eight areas of importance to mitigate spine disorders were identified through a voting process of the participating societies. Twelve recommendations were discussed and vetted.

RESULTS

The areas of immediate concern were "Aging spine," "Future of spine care," "Spinal cord injuries," "Children and adolescent spine," "Spine-related disability," "Spine Educational Standards," "Patient safety," and "Burden on economy." Twelve recommendations were created and endorsed by 31/33 spine societies and 2 journals globally during a vetted process through the SPINE20.org website and during the virtual inaugural meeting November 10-11, 2020 held from the G20 platform.

CONCLUSIONS

This is the first time that international spine societies have joined to support actions to mitigate the burden of spine disorders across the globe. SPINE20 seeks to change awareness and treatment of spine pain by supporting local projects that implement value-based practices with healthcare policies that are culturally sensitive based on scientific evidence.

2-step deep learning model for landmarks localization in spine radiographs

In this work we propose to use Deep Learning to automatically calculate the coordinates of the vertebral corners in sagittal x-rays images of the thoracolumbar spine and, from those landmarks, to calculate relevant radiological parameters such as L1–L5 and L1–S1 lordosis and sacral slope. For this purpose, we used 10,193 images annotated with the landmarks coordinates as the ground truth. We realized a model that consists of 2 steps. In step 1, we trained 2 Convolutional Neural Networks to identify each vertebra in the image and calculate the landmarks coordinates respectively. In step 2, we refined the localization using cropped images of a single vertebra as input to another convolutional neural network and we used geometrical transformations to map the corners to the original image. For the localization tasks, we used a differentiable spatial to numerical transform (DSNT) as the top layer. We evaluated the model both qualitatively and quantitatively on a set of 195 test images. The median localization errors relative to the vertebrae dimensions were 1.98% and 1.68% for x and y coordinates respectively. All the predicted angles were highly correlated with the ground truth, despite non-negligible absolute median errors of 1.84°, 2.43° and 1.98° for L1–L5, L1–S1 and SS respectively. Our model is able to calculate with good accuracy the coordinates of the vertebral corners and has a large potential for improving the reliability and repeatability of measurements in clinical tasks.

Effect of curve location on the severity index for adolescent idiopathic scoliosis: a longitudinal cohort study

OBJECTIVES

Adolescent idiopathic scoliosis (AIS) is the most common spinal disorder in children. A severity index was recently proposed to identify the stable from the progressive scoliosis at the first standardized biplanar radiographic exam. The aim of this work was to extend the validation of the severity index and to determine if curve location influences its predictive capabilities.

METHODS

AIS patients with Cobb angle between 10° and 25°, Risser 0-2, and no previous treatment were included. They underwent standing biplanar radiography and 3D reconstruction of the spine and pelvis, which allowed to calculate their severity index. Patients were grouped by curve location (thoracic, thoracolumbar, lumbar). Patients were followed up until skeletal maturity (Risser ≥ 3) or brace prescription. Their outcome was compared to the prediction made by the severity index.

RESULTS

In total, 205 AIS patients were included; 82% of them (155/189, 95% confidence interval [74-90%]) were correctly classified by the index, while 16 patients were unclassified. Positive predictive ratio was 78% and negative predictive ratio was 86%. Specificity (78%) was not significantly affected by curve location, while patients with thoracic and lumbar curves showed higher sensitivity (≥ 89%) than those with thoracolumbar curves (74%).

CONCLUSIONS

In this multicentric cohort of 205 patients, the severity index was used to predict the risk of progression from mild to moderate scoliosis, with similar results of typical major curve types. This index represents a novel tool to aid the clinician and the patient in the modulation of the follow-up and, for progressive patients, their decision for brace treatment.

KEY POINTS

• The severity index of adolescent idiopathic scoliosis has the potential to detect patients with progressive scoliosis as early as the first exam. • Out of 205 patients, 82% were correctly classified as either stable or progressive by the severity index. • The location of the main curve had small effect on the predictive capability of the index.

Does Capacitively Coupled Electric Fields Stimulation Improve Clinical Outcomes After Instrumented Spinal Fusion? A Multicentered Randomized, Prospective, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Lumbar spinal fusion (LSF) is used to treat lumbar degenerative disorders. Methods to improve the functional recovery of patients undergoing LSF is one of the main goals in daily clinical practice. The objective of this study is to assess whether biophysical stimulation with capacitively coupled electric fields (CCEF) can be used as adjuvant therapy to enhance clinical outcome in LSF-treated patients.

METHODS

Forty-two patients undergoing LSF were assessed and randomly allocated to either the active or to the placebo group. Follow-up visits were performed at 1, 3, 6, and 12 months after surgery; long-term follow-up was performed at year 10. Visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the 36-item Short Form Health Survey (SF-36) questionnaire were recorded.

RESULTS

This study demonstrates a significant improvement in CCEF-treated patients at 6 and 12 months' follow-up for SF-36, and at 12 months' follow-up for ODI values. Based on SF-36 and ODI scores, we reported a significantly higher percentage of successful treatments at 12 months in the active compared with the placebo group. Moreover, in a subset of patients at 10 years' follow-up, a significant difference was reported in VAS and ODI scores between groups.

CONCLUSIONS

The results demonstrate that 3 months of CCEF treatment immediately after surgery is effective in reducing ODI and improving SF-36 score, and that these benefits can be maintained up to 12 months. In a subset of patients, these positive outcomes are retained up to 10 years.

LEVEL OF EVIDENCE

I.

CLINICAL RELEVANCE

This study suggests that CCEF stimulation can be used as an adjunct to LSF for spine diseases, for increasing overall quality of life and improving patients' functional recovery. CCEF is safe and well tolerated, compatible with activities of daily living.

Multimodal exercises integrated with cognitive-behavioural therapy improve disability of patients with failed back surgery syndrome: a randomized controlled trial with one-year follow-up

PURPOSE

To evaluate the effect of multimodal exercises integrated with cognitive-behavioural therapy on disability, pain, and quality of life in patients suffering from failed back surgery syndrome (FBSS), and to appraise its extent in the long term.

METHODS

By means of a parallel-group superiority-controlled trial, 150 outpatients were randomly assigned to a 10-week individual-based multimodal programme of task-oriented exercises integrated with cognitive-behavioural therapy (experimental group, 75 patients) or individual-based general physiotherapy (control group, 75 patients). Before treatment, 10 weeks later (post-treatment), and 12 months after the end of treatment, the Oswestry Disability Index (primary outcome), the Tampa Scale for Kinesiophobia, the Pain Catastrophising Scale, a pain intensity numerical rating scale and the Short-Form Health Survey were evaluated. Linear mixed model analysis for repeated measures was carried out for each outcome measure.

RESULTS

Significant group (p < 0.001), time (p < 0.001), and time-by-group interaction (p < 0.001) effects were found for all outcome measures. Concerning disability, between-group differences (95% confidential interval) in favour of the experimental group of -9 (-10.7; -7.3) after training and of -13.2 (-14.7; -11.7) at follow-up were found. Also, kinesiophobia, catastrophising and pain showed significant between-group differences of 9, 12.5 and 1.7 points, respectively.

CONCLUSION

The multimodal intervention proposed was superior to general physiotherapy in reducing disability, kinesiophobia, catastrophising, and enhancing the quality of life of patients with FBSS. The effects were reinforced one year after the programme ended.IMPLICATIONS FOR REHABILITATIONMultimodal exercises integrated with cognitive-behavioural therapy induced significant improvements in disability, pain, kinesiophobia, catastrophising, and quality of life of subjects with Failed Back Surgery Syndrome.A well-integrated rehabilitative team which contributes towards reaching intervention goals is advised.Physiotherapists should adopt task-oriented exercises to promote an earlier return to common activities of disabled patients.Psychologists should explain how to modify useless beliefs and support adequate behaviours, in order to produce constructive attitudes towards perceived disability.

The use of triangular implants to enhance sacropelvic fixation: a finite element investigation

BACKGROUND CONTEXT

Long thoracolumbar fixation and fusion have become a consolidated treatment for severe spinal disorders. Concomitant sacropelvic fixation with S2 alar-iliac (S2AI) screws is frequently performed to limit instrumentation failure and pseudarthrosis at the lumbosacral junction.

PURPOSE

This study explored the use of triangular titanium implants in different configurations in which the implants supplemented standard sacropelvic fixation with S2AI screws in order to further increase the stability of S2AI fixation.

STUDY DESIGN

Finite element study.

METHODS

Four T10-pelvis instrumented models were built: pedicle screws and rods in T10-S1 (PED); pedicle screws and rods in T10-S1, and bilateral S2 alar-iliac screws (S2AI); pedicle screws and rods in T10-S1, bilateral S2AI screws, and triangular implants inserted bilaterally in a sacral alar-iliac trajectory (Tri-SAI); pedicle screws and rods in T10-S1, bilateral S2AI screws and two bilateral triangular titanium implants inserted in a lateral trajectory (Tri-Lat). The models were tested under pure moments of 7.5 Nm in flexion-extension, lateral bending and axial rotation.

RESULTS

SIJ motion was reduced by 50% to 66% after S2AI fixation; the addition of triangular titanium implants in either a SAI or a lateral trajectory further reduced it. S2AI, Tri-SAI, and Tri-Lat resulted in significantly lower stresses in S1 pedicle screws when compared to PED. Triangular implants had a protective effect on the maximal stresses in S2AI screws, especially when placed in the SAI trajectory. Sacropelvic fixation did not have any protective effect on the posterior rods.

CONCLUSIONS

Supplementing S2AI screws with triangular implants had a protective effect on the S2AI screws themselves, as well as the S1 pedicle screws, in the tested model.

CLINICAL SIGNIFICANCE

Triangular implants can substantially reduce the residual flexibility of the SIJ with respect to S2AI fixation alone, suggesting a possible role in patients needing reinforced fixation. In vivo investigation is needed to determine if these in vitro effects translate into clinically important differences.

In Vitro Study of Extracellular Vesicles Migration in Cartilage-Derived Osteoarthritis Samples Using Real-Time Quantitative Multimodal Nonlinear Optics Imaging

Mesenchymal stromal cells (MSCs)-derived extracellular vesicles (EVs) are promising therapeutic nano-carriers for the treatment of osteoarthritis (OA). The assessment of their uptake in tissues is mandatory but, to date, available technology does not allow to track and quantify incorporation in real-time. To fill this knowledge gap, the present study was intended to develop an innovative technology to determine kinetics of fluorescent MSC-EV uptake by means of time-lapse quantitative microscopy techniques. Adipose-derived mesenchymal stromal cells (ASCs)-EVs were fluorescently labeled and tracked during their uptake into chondrocytes micromasses or cartilage explants, both derived from OA patients. Immunofluorescence and time-lapse coherent anti-Stokes Raman scattering, second harmonic generation and two-photon excited fluorescence were used to follow and quantify incorporation. EVs penetration appeared quickly after few minutes and reached 30-40 μm depth after 5 h in both explants and micromasses. In explants, uptake was slightly faster, with EVs signal overlapping both extracellular matrix and chondrocytes, whereas in micromasses a more homogenous diffusion was observed. The finding of this study demonstrates that this innovative technology is a powerful tool to monitor EVs migration in tissues characterized by a complex extracellular network, and to obtain data resembling in vivo conditions.

Intervertebral disc and endplate cells response to IL-1β inflammatory cell priming and identification of molecular targets of tissue degeneration

Inflammation represents an important factor leading to metabolic imbalance within the intervertebral disc (IVD), conducive to degenerative changes. Therefore, a thorough knowledge of the IVD and endplate (EP) cell behaviour in such pathological environments is essential when designing regenerative therapeutic strategies. The present study aimed at assessing the molecular response of the IVD constitutive nucleus pulposus (NPCs)-, annulus fibrosus (AFCs)- and endplate (EPCs)-derived cells to interleukin (IL)-1β treatment, through large-scale, high-throughput microarray and protein analysis, identifying the differentially expressed genes and released proteins. Overall, the inflammatory stimulus downregulated stemness genes while upregulating pro-inflammatory, pro-angiogenic and catabolic genes, including matrix metalloproteases, which were not balanced by a concomitant upregulation of their inhibitors. Upregulation of anti-inflammatory and anabolic tumour necrosis factor inducible gene 6 protein (TNFAIP6), of IL-1 receptor antagonist (IL-1Ra) (at gene and protein levels) and of trophic insulin-like growth factor 1 (IGF1) was also observed in all cell types; IGF1 particularly in AFCs. An overall inhibitory effect of tumour necrosis factor alpha (TNFα) signal was observed in all cell types; however, EPCs showed the strongest anti-inflammatory behaviour. AFCs and EPCs shared the ability to limit the activation of the signalling mediated by specific chemokines. AFCs showed a slightly senescent attitude, with a downregulation of genes related to DNA repair or pro-mitosis. Results allowed for the identification of specific molecular targets in IVD and EP cells that respond to an inflammatory environment. Such targets can be either silenced (when pathological targets) or stimulated to counteract the inflammation.

Intervertebral disc and endplate cell characterisation highlights annulus fibrosus cells as the most promising for tissue-specific disc degeneration therapy

Degenerative processes of the intervertebral disc (IVD) and cartilaginous endplate lead to chronic spine pathologies. Several studies speculated on the intrinsic regenerative capacity of degenerated IVD related to the presence of local mesenchymal progenitors. However, a complete characterisation of the resident IVD cell populations, particularly that isolated from the endplate, is lacking. The purpose of the present study was to characterise the gene expression profiles of human nucleus pulposus (NPCs), annulus fibrosus (AFCs) and endplate (EPCs) cells, setting the basis for future studies aimed at identifying the most promising cells for regenerative purposes. Cells isolated from NP, AF and EP were analysed after in vitro expansion for their stemness ability, immunophenotype and gene profiles by large-scale microarray analysis. The three cell populations shared a similar clonogenic, adipogenic and osteogenic potential, as well as an immunophenotype with a pattern resembling that of mesenchymal stem cells. NPCs maintained the greatest chondrogenic potential and shared with EPCs the loss of proliferation capability during expansion. The largest number of selectively highly expressed stemness, chondrogenic/tissue-specific and surface genes was found in AFCs, thus representing the most promising source of tissue-specific expanded cells for the treatment of IVD degeneration.

Correction to: Interplay between low plasma RANKL and VDR-FokI polymorphism in lumbar disc herniation independently from age, body mass, and environmental factors: a case-control study in the Italian population

Under the headline "Correlation of RANKL concentrations and VDR-FokI polymorphism on disc herniation" in the description text for Table 2, the term "allelic frequency" was used erroneously for "genotypic frequency".

The strain distribution in the lumbar anterior longitudinal ligament is affected by the loading condition and bony features: An in vitro full-field analysis

The role of the ligaments is fundamental in determining the spine biomechanics in physiological and pathological conditions. The anterior longitudinal ligament (ALL) is fundamental in constraining motions especially in the sagittal plane. The ALL also confines the intervertebral discs, preventing herniation. The specific contribution of the ALL has indirectly been investigated in the past as a part of whole spine segments where the structural flexibility was measured. The mechanical properties of isolated ALL have been measured as well. The strain distribution in the ALL has never been measured under pseudo-physiological conditions, as part of multi-vertebra spine segments. This would help elucidate the biomechanical function of the ALL. The aim of this study was to investigate in depth the biomechanical function of the ALL in front of the lumbar vertebrae and of the intervertebral disc. Five lumbar cadaveric spine specimens were subjected to different loading scenarios (flexion-extension, lateral bending, axial torsion) using a state-of-the-art spine tester. The full-field strain distribution on the anterior surface was measured using digital image correlation (DIC) adapted and validated for application to spine segments. The measured strain maps were highly inhomogeneous: the ALL was generally more strained in front of the discs than in front of the vertebrae, with some locally higher strains both imputable to ligament fibers and related to local bony defects. The strain distributions were significantly different among the loading configurations, but also between opposite directions of loading (flexion vs. extension, right vs. left lateral bending, clockwise vs. counterclockwise torsion). This study allowed for the first time to assess the biomechanical behaviour of the anterior longitudinal ligament for the different loading of the spine. We were able to identify both the average trends, and the local effects related to osteophytes, a key feature indicative of spine degeneration.

What do we know about the biomechanics of the sacroiliac joint and of sacropelvic fixation? A literature review

The purpose of this review is to summarize the general knowledge about the biomechanics of the sacroiliac joint and sacropelvic fixation techniques. Additionally, this study aims to support biomechanical investigations in defining experimental protocols as well as numerical modeling of the sacropelvic structures. The sacroiliac joint is characterized by a large variability of shape and ranges of motion among individuals. Although the ligament network and the anatomical features strongly limit the joint movements, sacroiliac displacements and rotations are not negligible. Currently available treatments for sacroiliac joint dysfunction include physical therapy, steroid injections, Radio-frequency ablation of specific neural structures, and open or minimally invasive SIJ fusion. In long posterior construct, the most common solutions are the iliac screws and the S2 alar - iliac screws, whereas for the joint fixation alone, mini - invasive alternative system can be used. Several studies reported the clinical outcomes of the different techniques and investigated the biomechanical stability of the relative construct, but the effect of sacropelvic fixation techniques on the joint flexibility and on the stress generated into the bone is still unknown. In our opinion, more biomechanical analyses on the behavior of the sacroiliac joint may be performed in order to better predict the risk of failure or instability of the joint.

Biomechanics of sacropelvic fixation: a comprehensive finite element comparison of three techniques

PURPOSE

Sacropelvic fixation is frequently used in combination with thoracolumbar instrumentation for complex deformity correction and is commonly associated with pseudoarthrosis, implant failure and loosening. This study compared pedicle screw fixation (PED) with three different sacropelvic fixation techniques, namely iliac screws (IL), S2 alar-iliac screws (S2AI) and laterally placed triangular titanium implants (SI), all in combination with lumbosacral instrumentation, accounting for implant micromotion.

METHODS

Existing finite element models of pelvis-L5 of three patients including lumbopelvic instrumentation were utilized. Moments of 7.5 Nm in the three directions combined with a 500 N compressive load were simulated. Measured metrics included flexibility, instrumentation stresses and bone-implant interface loads.

RESULTS

Fixation effectively reduced the sacroiliac flexibility. Compared to PED, IL and S2AI induced a reduction in peak stresses in the S1 pedicle screws. Rod stresses were mostly unaffected by S2AI and SI, but IL demonstrated a stress increase. In comparison with a previous work depicting full osteointegration, SI was found to have similar instrumentation stresses as those due to PED.

CONCLUSIONS

Fixation with triangular implants did not result in stress increase on the lumbosacral instrumentation, likely due to the lack of connection with the posterior rods. IL and S2AI had a mild protective effect on S1 pedicle screws in terms of stresses and bone-implant loads. IL resulted in an increase in the rod stresses. A comparison between this study and previous work incorporating full osteointegration demonstrates how these results may be applied clinically to better understand the effects of different treatments on patient outcomes. These slides can be retrieved under Electronic Supplementary Material.

Physiological variations in the sagittal spine alignment in an asymptomatic elderly population

BACKGROUND CONTEXT

Sagittal plane alignment is of crucial importance for the treatment of spinal deformities. When planning corrective strategies, spine surgeons need to refer to normative parameters' ranges which characterize the alignment in the asymptomatic population. Changes are known to occur with age. For the Caucasian population, the reference ranges are extensively documented for the young and middle-aged adults. In contrast, only a few studies have evaluated individuals in advanced age (>60 years) and in groups of limited numbers of subjects (less than 50).

PURPOSE

To describe the normative parameter ranges of sagittal spine alignment in a large population of asymptomatic elderly subjects.

STUDY DESIGN/SETTING

Monocentric, prospective, cross-sectional study.

PATIENT SAMPLE

One hundred sixty asymptomatic elderly volunteers (age>60 years, Caucasian heritage), consecutively enrolled.

OUTCOME MEASURES

Sagittal parameters of spine and pelvis: thoracic kyphosis (TK); lumbar lordosis (LL); sacral slope (SS); pelvic incidence (PI); pelvic tilt (PT); sagittal vertical axis (SVA); T1 pelvic angle (TPA); mismatch between PI and LL (PI-LL); Roussouly classification of the lumbopelvic profile.

METHODS

Each subject underwent one radiographic scan, performed in standing position with EOS low-dose system (EOS Imaging, Paris, France). The radiographic images were processed with sterEOS software allowing identification of the anatomical parameters and the presence of scoliosis. SVA, TPA, and the lumbopelvic profile were manually measured in the lateral images. The results were compared to previous studies describing younger adult populations. The study was supported by the Italian Ministry of Health in the amount of $15,000. The authors declare that there are no conflicts of interests.

RESULTS

Overall, the average values of the spinopelvic parameters were the followings: TK, 55±14°; LL, 57±12°; PI, 55±11°; SS, 38±10°; PT, 16±7°. The average PI-LL, SVA, and TPA was -3±11°, 25±32 mm, and 14.6±7.4°, respectively. TK, TPA, and SVA were found increasing with age. As for classification of the lumbopelvic profile, 16% of subjects were excluded because they were considered not to belong to any of the Roussouly types. In the classified subjects, the distribution was similar to that of younger adults. Asymptomatic scoliosis (average Cobb angle, 22±7°) was identified in 27% of individuals.

CONCLUSIONS

The ranges of values pointed out differences compared to younger adults and represent an important resource for spine surgeons in planning the surgical correction of spinal deformities. The characteristic changes occurring with age, as well as the observed presence of mild or moderate asymptomatic scoliosis, should be carefully taken into account. The classification of the lumbopelvic profile based on the Roussouly scheme revealed some limitations, although similar frequencies were identified compared to younger adults.

Biomechanical in vitro comparison between anterior column realignment and pedicle subtraction osteotomy for severe sagittal imbalance correction

PURPOSE

To investigate the biomechanical effects of anterior column realignment (ACR) and pedicle subtraction osteotomy (PSO) on local lordosis correction, primary stability and rod strains.

METHODS

Seven cadaveric spine segments (T12-S1) underwent ACR at L1-L2. A stand-alone hyperlordotic cage was initially tested and then supplemented with posterior bilateral fixation. The same specimens already underwent a PSO at L4 stabilized by two rods, a supplemental central rod (three rods) and accessory rods (four rods) with and without adjacent interbody cages (La Barbera in Eur Spine J 27(9):2357-2366, 2018). In vitro flexibility tests were performed under pure moments in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) to determine the range of motion (RoM), while measuring the rod strains with strain gauge rosettes.

RESULTS

Local lordosis correction with ACR (24.7° ± 3.7°) and PSO (25.1° ± 3.9°) was similar. Bilateral fixation significantly reduced the RoM (FE: 31%, LB: 2%, AR: 18%), providing a stability consistent with PSO constructs (p > 0.05); however, it demonstrates significantly higher rod strains compared to PSO constructs with lateral accessory rods and interbody cages in FE and AR (p < 0.05), while being comparable in FE or slightly higher in AR compared to PSO constructs with two and three rods.

CONCLUSION

Bilateral posterior fixation is highly recommended following ACR to provide adequate primary stability. However, primary rod strains in ACR were found comparable or higher than weak PSO construct associated with frequent rod failure; therefore, caution is recommended. These slides can be retrieved under Electronic Supplementary Material.

Vitamin D's Effect on the Proliferation and Inflammation of Human Intervertebral Disc Cells in Relation to the Functional Vitamin D Receptor Gene FokI Polymorphism

Vitamin D is known to have immunomodulatory effects, is involved in osteo-cartilaginous metabolism, and may have a role in human intervertebral disc pathophysiology. Although a link between vitamin D receptor (VDR) gene variants and disc degeneration-related pathologies has been observed, its functional contribution to pathologic processes has not been assessed yet. The aim of this study was to investigate the response of disc cells to vitamin D in terms of the regulation of proliferation, metabolism, and inflammatory processes, with a particular focus on the FokI VDR genotype. However, although it was found that vitamin D had a pro-apoptotic effect regardless of genotype, an up-regulation of IL-1Ra and downregulation of IL-6 was found to be evident only in Ff cells. Regarding the metabolic effects, in Ff cells, vitamin D promoted an upregulation of the aggrecan in inflammatory conditions but did not have an effect on the expression of collagen-related markers. Moreover, cells bearing the Ff genotype were the most responsive to vitamin D in the upregulation of catabolic markers. In addition, in contrast to the FF genotype, vitamin D downregulated the vitamin D-dependent signaling pathway in inflamed Ff cells, counteracting the inflammation-mediated catabolic effects. In conclusion, Ff cells were found to be more responsive to the anti-inflammatory and catabolic effects of vitamin D, which is likely to be related to matrix remodeling.

Evaluation of Systemic Metal Diffusion after Spinal Pedicular Fixation with Titanium Alloy and Stainless Steel System: A 36-month Experimental Study in Sheep

It is known that titanium alloys cause more extensive local metallosis due to fretting corrosion than stainless steel implants.

The aim of the present study was to investigate possible systemic metal releases (Ti, Al, V, Cr, Ni) in sheep where L4–L5 were implanted with titanium alloy (Ti6Al4V, ASTM F 136) and stainless steel (AISI 316 L). 16 sheep were used: 8 were implanted with Ti6Al4V and 8 with stainless steel. At 6, 12, 24 and 36 months, the following examinations were performed: histology, atomic absorption spectrophotometry (AAS) and scanning electron microscopy (SEM), on liver, lung, kidney, brain, spleen and lumbo-aortic lymph nodes. Hair, urine and arteria blood samples were also analysed by AAS before implantation and at sacrifices. A histologic and ultrastructural study was performed on peri-implant tissues, too. Particular attention was paid to avoid contamination from dissection instruments or use of containers. In basal and in samples at 6 and 12 months, no metals were found in blood, urine, hair or other target tissues of the animals implanted with either Ti6Al4V or stainless steel. Regarding Al, V, Co and Ni, negative results in all tissues and body fluids were obtained also at 24 and 36 months. On the contrary, Ti traces were found in lumbo-aortic lymph nodes and lungs of one sheep only (10 and 30 ng/g, respectively) at 24 months. At 36 months, a systemic diffusion of Ti was observed in all tissues of both sheep instrumented with Ti6AI4V (2-16.5 ng/g), except for body fluids and hair.

Metal research in target tissues by light and SEM micro-probe analysis provided negative results. Current data suggest that the amount of Ti found in organs after stable pedicular fixation is extremely low and not biologically available. This observation would lead us to exclude the hypothesis of any toxic reaction and such a release seems to be due to the passive diffusion through lymphatic fluids. Additional studies are needed to confirm if this long-term release of Ti particles might cause tissue damage.

A comparative analysis of a disposable and a reusable pedicle screw instrument kit for lumbar arthrodesis: integrating HTA and MCDA

OBJECTIVE

Lumbar arthrodesis is a common surgical technique that consists of the fixation of one or more motion segments with pedicle screws and rods. However, spinal surgery using these techniques is expensive and has a significant impact on the budgets of hospitals and Healthcare Systems. While reusable and disposable instruments for laparoscopic interventions have been studied in literature, no specific information exists regarding instrument kits for lumbar arthrodesis. The aim of the present study was to perform a complete health technology assessment comparing a disposable instrument kit for lumbar arthrodesis (innovative device) with the standard reusable instrument.

METHODS

A prospective and observational study was implemented, by means of investigation of administrative records of patients undergoing a lumbar arthrodesis surgical procedure. The evaluation was conducted in 2013, over a 12- month time horizon, considering all the procedures carried out using the two technologies. A complete health technology assessment and a multi-criteria decision analysis approach were implemented in order to compare the two alternative technologies. Economic impact (with the implementation of an activity based costing approach), social, ethical, organisational, and technology-related aspects were taken into account.

RESULTS

Although the cost analysis produced similar results in the comparison of the two technologies (total cost equal to € 4,279.1 and € 4,242.6 for reusable instrument kit and the disposable one respectively), a significant difference between the two instrument kits was noted, in particular concerning the organisational impact and the patient safety.

CONCLUSIONS

The replacement of a reusable instrument kit for lumbar arthrodesis, with a disposable one, could improve the management of this kind of devices in hospital settings.

Semi-quantitative evaluation of signal intensity and contrast-enhancement in Modic changes

Background

Semi-quantitative evaluation of Modic changes (MCs) has recently been proposed as a way to standardise and increase repeatability of clinical studies. This study is aimed at developing semi-quantitative measures of enhancement, given by contrast agent injection, on T1-weighted images in MCs, and to investigate their reliability and relation with MC types.

Methods

Thirty-seven subjects suffering from low back pain underwent T1-weighted and T2-weighted turbo spin-echo sequences. Five minutes after the injection of a paramagnetic contrast agent, a second T1-weighted sequence was acquired. Regions of interest (ROIs) corresponding to MCs were selected manually on the unenhanced image; control ROIs in the “healthy” bone marrow were selected. For each ROI, the mean signal intensity (SI) of unenhanced pixels and the mean absolute and normalised difference in SI between unenhanced and contrast-enhanced pixels values were calculated.

Results

A total of 103 MCs were recognised and 61 were semi-quantitatively analysed: 16 type I, 34 type II and 11 type I/II. Regarding controls, MCs I showed a lower SI on the unenhanced T1-weighted images and a marked contrast enhancement (CE); MCs II showed a higher SI than controls on unenhanced images and a lower or comparable CE; and MCs I/II presented an intermediate SI on the unenhanced images and a marked CE. Inter-rater and intra-rater agreements were found to be excellent or substantial.

Conclusions

Semi-quantitative measurements could differentiate MC types in terms of unenhanced SI and of CE with respect to “healthy” bone marrow.

Plasma vitamin D and osteo-cartilaginous markers in Italian males affected by intervertebral disc degeneration: Focus on seasonal and pathological trend of type II collagen degradation

OBJECTIVE

To evaluate plasma vitamin D and cross-linked C-telopeptides of type I (CTx-I) and type II (CTx-II) collagen concentrations in males with lumbar intervertebral disc degeneration (IVD) compared to healthy controls. Improved knowledge might suggest to optimize the vitamin D status of IVD patients and contribute to clarify mechanisms of cartilage degradation.

METHODS

79 Italian males with lumbar IVD assessed by Magnetic Resonance Imaging (MRI) and 79 age, sex and BMI-matched healthy controls were enrolled. Plasma 25hydroxyvitamin D (25(OH)D), CTx-I and CTx-II were measured by immunoassays. Circannual seasonality, correlation between biomarkers concentrations and clinical variables were assessed.

RESULTS

Overall subjects 25(OH)D and CTx-II showed month rhythmicity with acrophase in August/September and October/November, and nadir in February/March and April/May, respectively. An inverse correlation between 25(OH)D and CTx-I, and a direct correlation between CTx-II and CTx-I were observed. IVD patients, particularly with osteochondrosis, showed higher CTx-II than healthy controls.

CONCLUSIONS

Month of sampling may affect plasma 25(OH)D and CTx-II concentrations. The correlation between CTx-I and CTx-II suggests an interplay between the osteo-cartilaginous endplate and the fibro-cartilaginous disc. The results of this study highlighted that osteochondrosis associates with increased cartilaginous catabolism. Vitamin D supplementation seems more necessary in winter for lumbar IVD patients.

Semiautomated 3D Spine Reconstruction from Biplanar Radiographic Images: Prediction of Intervertebral Loading in Scoliotic Subjects

The present study proposes a semiautomatic software approach to reconstruct 3D subject-specific musculoskeletal model of thoracolumbar spine from radiographic digitized images acquired with EOS system. The approach is applied to evaluate the intervertebral loads in 38 standing adolescents with mild idiopathic scoliosis. For each vertebra, a set of landmarks was manually identified on radiographic images. The landmark coordinates were processed to calculate the following vertebral geometrical properties in the 3D space (i) location (ii) dimensions; and (iii) rotations. Spherical joints simulated disks, ligaments, and facet joints. Body weight distribution, muscles forces, and insertion points were placed according to physiological-anatomical values. Inverse static analysis, calculating joints' reactions in maintaining assigned spine configuration, was performed with AnyBody software. Reaction forces were computed to quantify intervertebral loads, and correlation with the patient anatomical parameters was then checked. Preliminary validation was performed comparing the model outcomes with that obtained from other authors in previous modeling works and from in vivo measurements. The comparison with previous modeling works and in vivo studies partially fulfilled the preliminary validation purpose. However, minor incongruities were pointed out that need further investigations. The subjects' intervertebral loads were found significantly correlated with the anatomical parameters in the sagittal and axial planes. Despite preliminary encouraging results that support model suitability, future investigations to consolidate the proposed approach are necessary. Nonetheless, the present method appears to be a promising tool that once fully validated could allow the subject-specific non-invasive evaluation of a deformed spine, providing supplementary information to the routine clinical examination and surgical intervention planning.

La nostra esperienza nel trattamento dei conflitti disco-radicolari e delle radicolopatie post-chirurgiche con ossigeno-ozono terapia infiltrativa paravertebrale

Gli autori presentano i risultati del trattamento con O2-O3 paravertebrale in 182 pazienti affetti da cervico e lomboradicoliti di diversa origine. Si segnala il riscontro di risultati positivi in oltre i due terzi dei pazienti nella patologia da conflitto disco-radicolare e nel 44% degli arruolati per radicolopatia post-chirurgica, mentre sono giudicati meno soddisfacenti i risultati in presenza di altre patologie vertebrali degenerative o malformative.

MR Imaging and Radiographic Imaging of Degenerative Spine Disorders and Spine Alignment

Advances in MR imaging technologies, as well as the widening of their availability, boosted their use in the diagnosis of spinal disorders and in the preoperative planning of spine surgeries. However, the most consolidated approach to the assessment of adult patients with spinal disorders is based on the analysis of full standing radiographs (posteroanterior and laterolateral views). In this article, the radiographic spinal and pelvic parameters, which have relevance in the clinical management of adults with spinal disorders, are summarized.

BsmI, ApaI and TaqI Polymorphisms in the Vitamin D Receptor Gene (VDR) and Association with Lumbar Spine Pathologies: An Italian Case-Control Study

Three adjacent single nucleotide polymorphisms of the vitamin D receptor gene (VDR) BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) are commonly studied in several pathologies. We aimed to evaluate the distribution of VDR BsmI, ApaI, and TaqI allele, genotype, and haplotype frequencies in an Italian cohort of 266 patients with lumbar spine disorders assessed by Magnetic Resonance Imaging and 252 asymptomatic controls. The exposure to putative risk factors was evaluated by a questionnaire. Polymorphisms were detected by PCR-RFLP and TaqMan^® SNP Genotyping Assay. The results were statistically adjusted for the identified conventional risk factors. The three SNPs were in linkage disequilibrium. For all cases BbAaTT was a 3-fold risk factor OR = 3.38), whereas bbAATT (OR = 0.22), and bbaaTT (OR = 0.47) genotypes were found to be protective. Specifically, for patients affected by disc herniation only (n = 88) and all lumbar pathologies excluding stenosis and/or spondylolistesis (n = 215) B allele, Bb, Aa, and BbAaTT genotypes were risky, whereas b allele, bb, aa, and bbaaTT genotypes were protective. In patients affected by osteochondrosis with or without disc hernation (n = 50), T allele, Aa, and bbAaTT genotypes were risky, whereas t allele, AA, tt genotypes were protective. In patients affected by stenosis and/or spondylolistesis (n = 51) no significant associations were found. This is the first study showing an association of the three genetic VDR variants BsmI, ApaI, and TaqI and lumbar spine pathologies. Our study contributes to delineate genetic risk factors for specific subgroups of patients with lumbar spine pathologies highlighting the importance of haplotype analysis, and of detailed clinical evaluation of the patients for identification of genetic biomarkers.