Is remaining intervertebral disc tissue interfering with bone generation during fusion of two vertebrae?

Study Design: laboratory research.

Background: Through the increasing number of minimally invasive procedures in spinal fusion surgery, the complete removal of intervertebral disc (IVD) tissue has become more a challenge. Remaining IVD may interfere with the biological process of bone formation.

Biomechanical evaluation of two minimal access interbody cage designs in a cadaveric model.

Background: Different interbody grafts have been employed and evaluated for spinal fusion surgery. The Memory Metal Minimal Access Cage (MAC) is a hollow horseshoe shaped interbody fusion concept which provides a potentially major advantage with their small cage contact area and large graft space in comparison with other vertical cages.

Methods: This Biomechanical Cadaveric Study evaluates the primary stability and the amount of acute subsidence occurring in two new MAC cage designs; the Niti-l and Niti-s.

Coupled motions in human and porcine thoracic and lumbar spines.

Coupled motions, i.e., motions along axes other than the loaded axis, have been reported to occur in the human spine, and are likely to be influenced by inclined local axes due to the sagittal plane spine curvature.

The balance between proliferation and transcription of angiogenic factors of mesenchymal stem cells in hypoxia.

Bridging large bone defects with mesenchymal stromal cells-seeded scaffolds remains a big challenge in orthopedic surgery, due to the lack of vascularization. Within such a cell-scaffold construct, cells are exposed to ischemic conditions. When human mesenchymal stem cells (hMSCs) encounter hypoxic conditions, they show higher cell proliferation than at ambient oxygen levels.

Control of oxygen release from peroxides using polymers.

An important limitation in cell therapy for the regeneration of tissue is the initial lack of oxygen. After implantation of large 3D cell-seeded structures, cells die rather than contribute to tissue regenerating. Here we've tested oxygen-releasing materials to improve cell survival and growth after implantation.

Altered head orientation patterns in children with idiopathic scoliosis in conditions with sensory conflict.

Purpose: Idiopathic scoliosis (IS) is the most common spinal deformity in adolescents. Defective postural equilibrium may be a contributing factor. The information of the three sensory systems combined enables the formation of a central representation of head position and body posture.

Static versus vacuum cell seeding on high and low porosity ceramic scaffolds.

An adequate cell seeding technique is essential for effective bone regeneration on cell seeded constructs of porous tricalcium phosphates. In previous studies, dynamic cell seeding, in which an external force is applied to seed cells on a biomaterial, resulted in more homogeneous cell seeding in low porosity scaffolds than static seeding. The optimal cell seeding technique for high porosity scaffolds has not been defined yet.

A new lumbar posterior fixation system, the memory metal spinal system: an in-vitro mechanical evaluation.

Background: Spinal systems that are currently available for correction of spinal deformities or degeneration such as lumbar spondylolisthesis or degenerative disc disease use components manufactured from stainless steel or titanium and typically comprise two spinal rods with associated connection devices (for example: DePuy Spines Titanium Moss Miami Spinal System). The Memory Metal Spinal System of this study consists of a single square spinal rod made of a nickel titanium alloy (Nitinol) used in conjunction with connecting transverse bridges and pedicle screws made of Ti-alloy. Nitinol is best known for its shape memory effect, but is also characterized by its higher flexibility when compared to either stainless steel or titanium.

Automatic Cobb angle determination from radiographic images.

Study Design: Automatic measurement of Cobb angle in patients with scoliosis.

Objective: To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images.

Summary Of Background Data: Thirty-six frontal radiographical images of patients with scoliosis.

The Memory Metal Spinal System in a Posterior Lumbar Interbody Fusion (PLIF) Procedure: A Prospective, Non-Comparative Study to Evaluate the Safety and Performance.

Study Design: A prospective, non-comparative study of 27 patients to evaluate the safety and performance of the Memory Metal Spinal System used in a PLIF procedure in the treatment of spondylolisthesis, symptomatic spinal stenosis or degenerative disc disease (DDD).

Objective: To evaluate the clinical performance, radiological outcome and safety of the Memory Metal Spinal System, used in a PLIF procedure, in the treatment of spondylolisthesis, symptomatic spinal stenosis or degenerative disc disease in human subjects.

Summary Of Background Data: Spinal systems that are currently available for correction of spinal deformities or degeneration such as lumbar spondylosis or degenerative disc disease, use components manufactured from stainless steel or titanium and typically comprise two spinal rods with associated connection devices.

The memory metal minimal access cage: a new concept in lumbar interbody fusion-a prospective, noncomparative study to evaluate the safety and performance.

Study Design/Objective. A single-centre, prospective, non-comparative study of 25 patients to evaluate the performance and safety of the Memory Metal Minimal Access Cage (MAC) in Lumbar Interbody Fusion. Summary of Background Data.

Cervical cystic swelling in an adolescent: unusual association of a cervical mature teratoma with vertebral anomalies and a history of gastric duplication cyst.

A 14-year-old girl presented with a cervical cystic swelling in association with deformity of cervical vertebrae. As a child, she had been treated for gastric duplication. Pathologic examination of the resected cervical swelling revealed a mature teratoma.

Predicting the peak growth velocity in the individual child: validation of a new growth model.

Predicting the peak growth velocity in an individual patient with adolescent idiopathic scoliosis is essential or determining the prognosis of the disorder and timing of the (surgical) treatment. Until the present time, no accurate method has been found to predict the timing and magnitude of the pubertal growth spurt in the individual child. A mathematical model was developed in which the partial individual growth velocity curve was linked to the generic growth velocity curve.

Influence of interpersonal geometrical variation on spinal motion segment stiffness: implications for patient-specific modeling.

Study Design: A validated finite element model of an L3-L4 motion segment is used to analyze the effects of interpersonal differences in geometry on spinal stiffness.

Objective: The objective of this study is to determine which of the interpersonal variations of the geometry of the spine have a large effect on spinal stiffness. This will improve patient-specific modeling.

The effects of creep and recovery on the in vitro biomechanical characteristics of human multi-level thoracolumbar spinal segments.

Background: Several physiological and pathological conditions in daily life cause sustained static bending or torsion loads on the spine resulting in creep of spinal segments. The objective of this study was to determine the effects of creep and recovery on the range of motion, neutral zone, and neutral zone stiffness of thoracolumbar multi-level spinal segments in flexion, extension, lateral bending and axial rotation.

Methods: Six human cadaveric spines (age at time of death 55-84 years) were sectioned in T1-T4, T5-T8, T9-T12, and L1-L4 segments and prepared for testing.

The value of shoe size for prediction of the timing of the pubertal growth spurt.

Background: Knowing the timing of the pubertal growth spurt of the spine, represented by sitting height, is essential for the prognosis and therapy of adolescent idiopathic scoliosis. There are several indicators that reflect growth or remaining growth of the patient. For example, distal body parts have their growth spurt earlier in adolescence, and therefore the growth of the foot can be an early indicator for the growth spurt of sitting height.

The growth of different body length dimensions is not predictive for the peak growth velocity of sitting height in the individual child.

The aim of this study was to determine whether the differences in timing of the peak growth velocity (PGV) between sitting height, total body height, subischial leg length, and foot length can be used to predict whether the individual patient with adolescent idiopathic scoliosis is before or past his or her PGV of sitting height. Furthermore, ratios of growth of different body parts were considered in order to determine their value in prediction of the PGV of sitting height in the individual patient. Ages of the PGV were determined for sitting height (n=360), total body height (n=432), subischial leg length (n=357), and foot length (n=263), and compared for the whole group and for the individual child in particular.

Predicting growth and curve progression in the individual patient with adolescent idiopathic scoliosis: design of a prospective longitudinal cohort study.

Background: Scoliosis is present in 3-5% of the children in the adolescent age group, with a higher incidence in females. Treatment of adolescent idiopathic scoliosis is mainly dependent on the progression of the scoliotic curve. There is a close relationship between curve progression and rapid (spinal) growth of the patient during puberty.

Reproducibility of standing posture for X-ray radiography: a feasibility study of the BalancAid with healthy young subjects.

Unreliable spinal X-ray radiography measurement due to standing postural variability can be minimized by using positional supports. In this study, we introduce a balancing device, named BalancAid, to position the patients in a reproducible position during spinal X-ray radiography. This study aimed to investigate the performance of healthy young subjects' standing posture on the BalancAid compared to standing on the ground mimicking the standard X-rays posture in producing a reproducible posture for the spinal X-ray radiography.

A framework for human spine imaging using a freehand 3D ultrasound system.

The use of 3D ultrasound imaging to follow the progression of scoliosis, i.e., a 3D deformation of the spine, is described.

The effect of three-dimensional geometrical changes during adolescent growth on the biomechanics of a spinal motion segment.

During adolescent growth, vertebrae and intervertebral discs undergo various geometrical changes. Although such changes in geometry are well known, their effects on spinal stiffness remains poorly understood. However, this understanding is essential in the treatment of spinal abnormalities during growth, such as scoliosis.

Comparative anatomical dimensions of the complete human and porcine spine.

New spinal implants and surgical procedures are often tested pre-clinically on human cadaver spines. However, the availability of fresh frozen human cadaver material is very limited and alternative animal spines are more easily available in all desired age groups, and have more uniform geometrical and biomechanical properties. The porcine spine is said to be the most representative model for the human spine but a complete anatomical comparison is lacking.

In vitro biomechanical characteristics of the spine: a comparison between human and porcine spinal segments.

Study Design: An in vitro study on human and porcine multilevel spinal segments.

Objective: To compare human and porcine thoracolumbar spinal segments with respect to their biomechanical characteristics and the effects of creep, recovery, and removal of ligaments and posterior parts on the biomechanical characteristics.

Summary Of Background Data: Availability of human cadaver spines for in vitro testing of new spinal implants and surgical procedures is limited.

Biomechanical characteristics of different regions of the human spine: an in vitro study on multilevel spinal segments.

STUDY DESIGN.: An in vitro study on human multilevel spinal segments. OBJECTIVE.

Geometry of the intervertebral volume and vertebral endplates of the human spine.

Replacement of a degenerated vertebral disc with an artificial intervertebral disc (AID) is currently possible, but poses problems, mainly in the force distribution through the vertebral column. Data on the intervertebral disc space geometry will provide a better fit of the prosthesis to the vertebrae, but current literature on vertebral disc geometry is very scarce or not suitable. In this study, existing CT-scans of 77 patients were analyzed to measure the intervertebral disc and vertebral endplate geometry of the lumbar spine.