ProDisc–C versus anterior cervical discectomy and fusion for the surgical treatment of symptomatic cervical disc disease: two-year outcomes of Asian prospective randomized controlled multicentre study

European Spine Journal - Our study aimed to evaluate non-inferiority of ProDisc-C to anterior cervical discectomy and fusion (ACDF) in terms of clinical outcomes and incidence of adjacent segment...     

Normal variation in sagittal spinal alignment parameters in adult patients: an EOS study using serial imaging

Purpose

To describe normal variations in sagittal spinal radiographic parameters over an interval period and establish physiological norms and guidelines for which these images should be interpreted.

Methods

Data were prospectively collected from a continuous series of adult patients with first-episode mild low back pain presenting to a single institution. The sagittal parameters of two serial radiographic images taken 6-months apart were obtained with the EOS^® slot scanner. Measured parameters include CL, TK, TL, LL, PI, PT, SS, and end and apical vertebrae. Chi-squared test and Wilcoxon Signed Rank test were used to compare categorical and continuous variables, respectively.

Results

Sixty patients with a total of 120 whole-body sagittal X-rays were analysed. Mean age was 52.1 years (SD 21.2). Mean interval between the first and second X-rays was 126.2 days (SD 47.2). Small variations (< 1°) occur for all except PT (1.2°), CL (1.2°), and SVA (2.9 cm). Pelvic tilt showed significant difference between two images (p = 0.035). Subgroup analysis based on the time interval between X-rays, and between the first and second X-rays, did not show significant differences. Consistent findings were found for end and apical vertebrae of the thoracic and lumbar spine between the first and second X-rays for sagittal curve shapes.

Conclusions

Radiographic sagittal parameters vary between serial images and reflect dynamism in spinal balancing. SVA and PT are predisposed to the widest variation. SVA has the largest variation between individuals of low pelvic tilt. Therefore, interpretation of these parameters should be patient specific and relies on trends rather than a one-time assessment.

     

Biological performance of a polycaprolactone-based scaffold used as fusion cage device in a large animal model of spinal reconstructive surgery

A bioactive and bioresorbable scaffold fabricated from medical grade poly (epsilon-caprolactone) and incorporating 20% beta-tricalcium phosphate (mPCL–TCP) was recently developed for bone regeneration at load bearing sites. In the present study, we aimed to evaluate bone ingrowth into mPCL–TCP in a large animal model of lumbar interbody fusion. Six pigs underwent a 2-level (L3/4; L5/6) anterior lumbar interbody fusion (ALIF) implanted with mPCL–TCP + 0.6 mg rhBMP-2 as treatment group while four other pigs implanted with autogenous bone graft served as control. Computed tomographic scanning and histology revealed complete defect bridging in all (100%) specimen from the treatment group as early as 3 months. Histological evidence of continuing bone remodeling and maturation was observed at 6 months. In the control group, only partial bridging was observed at 3 months and only 50% of segments in this group showed complete defect bridging at 6 months. Furthermore, 25% of segments in the control group showed evidence of graft fracture, resorption and pseudoarthrosis. In contrast, no evidence of graft fractures, pseudoarthrosis or foreign body reaction was observed in the treatment group. These results reveal that mPCL–TCP scaffolds could act as bone graft substitutes by providing a suitable environment for bone regeneration in a dynamic load bearing setting such as in a porcine model of interbody spine fusion.     

T9 versus T10 as the upper instrumented vertebra for correction of adult deformity—rationale and recommendations

Background Context

Adult spinal deformity correction sometimes involves long posterior pedicle screw constructs extending from the lumbosacral spine to the thoracic vertebra. As fusion obliterates motion and places supraphysiological stress on adjacent spinal segments, it is crucial to ascertain the ideal upper instrumented vertebra (UIV) to minimize risk of proximal junctional failure (PJF). The T10 vertebra is often chosen to allow bridging of the thoracolumbar junction into the immobile thoracic vertebrae on the basis that it is the lowest immobile thoracic vertebra strut by the rib cage.

The natural history of adolescent idiopathic scoliosis

There have been great advances in the conservative and surgical treatment for adolescent idiopathic scoliosis in the last few decades. The challenge for the physician is the decision for the optimal time to institute therapy for the individual child. This makes an understanding of the natural history and risk factors for curve progression of significant importance. Reported rates of curve progression vary from 1.6% for skeletally mature children with a small curve magnitude to 68% for skeletally immature children with larger curve magnitudes. Although the patient''s age at presentation, the Risser sign, the patient''s menarchal status and the magnitude of the curve have been described as risk factors for curve progression, there is evidence that the absolute curve magnitude at presentation may be most predictive of progression in the long term. A curve magnitude of 25° at presentation may be predictive of a greater risk of curve progression. Advances in research may unlock novel predictive factors, which are based on the underlying pathogenesis of this disorder.     

Variation of the cervical spinal Torg ratio with gender and ethnicity.

BACKGROUND CONTEXT: The Torg ratio is used as a universal indicator of cervical canal stenosis despite reports of differences between gender and race. Normal values of this ratio have been established for subjects of different ethnicity, but the differences between genders and race have not been critically compared. PURPOSE: To establish normal cervical spinal dimensions and analyze the differences observed between men and women, and between reports using subjects of different ethnicity. STUDY DESIGN/SETTING: Observational. PATIENT SAMPLE: Forty men and 40 women of Chinese descent with no history or symptoms of neck pathology selected from patients presenting to the Emergency Department for foreign body ingestion. OUTCOME MEASURES: Measurements of the sagittal developmental diameter (SDD) and vertebral body diameter (VB) on the lateral cervical radiograph with calculation of SDD/VB (Torg ratio). METHODS: Lateral radiographs of the cervical spine were taken in a standardized manner with a 180-cm film-to-tube distance. Comparison was made between genders in the study population and with previous reports on subjects of different ethnicity. RESULTS: The SDD was narrowest at the C4 level in both men and women. Women had smaller SDDs at all levels of the cervical spine. Female VBs were of sizes similar to their corresponding SDDs, whereas men had larger VBs. This resulted in small Torg ratios in men averaging 0.87. Comparison with previous reports demonstrated consistent variation in the SDD, which increased serially from Japanese, through Chinese and Indian, to white subjects. The relationship of VB to the corresponding SDD displayed wide variation between reports. This resulted in Torg ratios differing not only between subjects of different ethnicity but also between genders within the same population. CONCLUSIONS: The Torg ratio is not a consistent indicator of the SDD and may not be used to reliably identify the presence of cervical canal stenosis.     

Reproducibility of sagittal radiographic parameters in adolescent idiopathic scoliosis—a guide to reference values using serial imaging

Background Context

Knowledge of sagittal radiographic parameters in adolescent idiopathic scoliosis (AIS) patients has not yet caught up with our understanding of their roles in patients with adult spinal deformity. It is likely that more emphasis will be placed in restoring sagittal parameters for AIS patients in the future. Therefore, we need to understand how these parameters may vary in AIS to facilitate management plans.

Minimally invasive iliac screw fixation in treating painful metastatic lumbosacral deformity: a technique description and clinical results

Introduction

Pelvic fixation via iliac screws is a crucial technique in stabilizing metastatic lumbosacral deformity. MIS iliac screw fixation avoids complications of an open approach and is a viable palliative option in treating patients with painful instability and advanced disease, unsuited for major reconstruction. In this paper we describe the use of MIS iliac screw fixation in treatment of painful metastatic LSJ deformity, highlighting our treatment rationale, selection criteria, technical experience and outcomes.

Methods

Five patients with lumbosacral metastatic deformity who underwent MIS lumbopelvic stabilization using iliac screws were prospectively studied. Patients had severe axial back pain in erect posture with significant resolution when supine. All patients had advanced disease with unfavorable tumor scores for major spinal reconstruction.

Results

Mean cohort age was 62 years. Median pre-op SIN and Tokuhashi scores were 13 and 9, respectively. All patients were instrumented successfully without conversion to open technique. Mean preoperative and postoperative Cobb angle was 11° and 5.4°, respectively. There were no neurological deficits or wound complications postop. Postoperative CT scans showed no iliac screw and sacroiliac joint bony violation. Mean time for commencement of adjuvant therapy was 2.8 weeks. Average follow-up was 13.2 months. No screw breakage, wound complication, symptomatic implant prominence and SI joint pain were noted at last follow-up.

Conclusion

MIS iliac screw fixation is feasible, reproducible and can be employed without complications in metastatic spine. This opens a new avenue of surgical management for metastatic lumbosacral disease patients, who otherwise may be inoperable and provide better soft tissue control and earlier postoperative adjuvant treatment opportunity.