Purpose
The purpose of this study is to track chondrocytic cells interaction with notochordal cells by an in vitro biologic assays which measure chondrocytic cells activities using robotic time-lapsed microscopic imaging system. Overview of Literature: Although chondrocytic cells and notochordal cells play critical roles in homeostasis of the intervertebral disc, their real-time interaction has not been studied.
Materials and Methods
Chondrocytic cells and notochordal cells purified from rabbit nucleus pulposus were isolated after serial filtration. Both cells were plated in 24 well-culture plates and then were co-cultured for timelapsed cell tracking study. After numerous locations of each well were selected for time-lapsed analysis, both cells were tracked by visible imaging every 10 minutes over 5 days. Biochemical information were done to compare matrix protein expression by gene expression (collagen II and aggrecan) using reverse transcription polymerase chain reaction (RT-PCR).
Results
In time-lapsed cell tracking analysis, mobility of chondrocytic cells were shown significantly faster than vacuolated notochordal cells although both cells were similar in cytoplasmic area. Chondrocytic cells cocultured with notochordal cells frequently interacted with neighbor vacuolated notochordal cells and increased mitotic fraction and velocity, and decreased population doubling time (PDT) compared with chondrocyte-like cells alone, which are consistent with results of collagen II expression. Aggrecan expression levels did not show any significance.
Conclusion
These results are the first direct evidences of chondrocytic cells activities with notochordal cells in vitro 2-D culture using both individual cell tracking and cell population tracking in real-time with high-throughput experimental capability. This novel system provides ability to quantify numerous and unique temporal changes in chondrotic cells and notochordal cells, and essential information to indentify supporting function of notochordal cells in intervertebral disc, suggesting that this system has the potential to use in disc homeostasis research.

Purpose
The purpose of this study was to determine the early failure rate of percutaneous epidural neuroplasty (PEN) that led to subsequent decompressive lumbar surgery. We also assessed the limits of spinal pain management by using the current PEN technique.
Materials and Methods
We classified 1763 cases according to their diagnoses and radiological findings. Patients who underwent subsequent open surgery when PEN failed to improve or aggravated their symptoms were included.
Results
All 37 patients underwent open decompressive surgery within 3 months after PEN. There were 18 in the intracanalicular focal herniation category, 11 in intracanalicular broad based herniation category, and 8 in foraminal category; the early failure rates were 1.7%, 1.9%, and 5.6%, respectively. There was no significant statistical difference between the intracanalicular categories with regard to failure rate, but the foraminal category had a higher rate of failure than that of intracanalicular categories (p<0.05). Moreover, there were 11 cases in intracanalicular categories that experienced deterioration or new symptoms due to posterior longitudinal ligament rupture or fragment migration. Among these, there were 9 cases (82%) with preexisting intracanalicular migrating fragments.
Conclusion
PEN with targeted drug delivery may be an effective treatment for low back pain and/or radiculopathy. However, its early failure rate is at least 2.1%, and the presence of intracanalicular migrating fragments or symptomatic foraminal lesions are predictors of poor outcome. Patients must be carefully selected on the basis of thorough radiologic reviews to improve the rate of satisfactory PEN outcomes.

Purpose
Pull-out of pedicle screw in posterior pedicle fixation for thoracic and lumbar burst fractures causes delayed rehabilitation, persistant pain, and imblance of sagittal plane. In this study we try to analyse the factors that cause the pull-out of pedicle screw.
Materials and Methods
From March 01, 2006 to December 31, 2009, we assorted into two group; Group I for pullout pedicle, Group II for control. Plane lateral x-ray view film of thoracolumbar spine was taken on preoperation, postoperation, the first time when screw was pulled out and last follow up. we measure inserted angle for the upper endplate of screw, convergency angle and change of body height loss and kyphotic angle. We analysed corelation between these measuring values and pedicle screw pull-out by Mann-Whitney test and T-test.
Results
Pull-out of pedicle screw was found at mean 5weeks among nine cases. For inserted pedicle screws, which place in upper and lower vertebral body of fractured one, Value of inserted angle for upper end plate and convergency angle was found non-significant(p>0.05, Mann-Whitney test). Restoration of height loss and kyphotic angle of fractured vertebral body was statically significant(p<0.05, T-test).
Conclusion
In posterior pedicle fixation for thoracic and lumbar burst fractures, sufficient restoration of height loss and kyphotic angle is important factor for prevention of screw pull-out than inserted angle for upper end plate and convergency angle at a short period of time. Therefore we think that sufficient anterior fixation of vertebral body and restoration of kyphotic angle have a decisive effect on prognosis of patients.

Variable posterior surgical techniques for atlantoaxial (C1-2) joint instability (AAI) have been introduced and advanced steadily during the past century. Many surgical techniques using wire or clamp were introduced before 1980s and these surgical approaches provided low biomechanical strength and low fusion rate. After then, screwbased techniques (trans-articular or segmental fixation) were introduced and popularized as an alternative or “gold standard” method. Screw-based methods have recently gained popularity and modified according to their targeted anatomical regions (pedicle, posterior arch, C1 lateral mass, pars inter-articularis and laminar). Each surgical technique has own strength and weaknesses, and their usefulness has been proved through many biomechanical analysis and clinical applications. Advantage and limitation of each surgical technique will be reviewed.

Injection therapy is a major component of conservative management for spinal disorders like herniated nucleus pulposus (HNP) and spinal stenosis. The most common problem faced during the injection – transforaminal, interlaminar or caudal epidural block is delivering the drug at the exact site of lesion due to adhesions more so when there has been a previous open spinal surgery. Conventional neurolysis effect was limited because adhesiolysis and drug delivery were in the posterior epidural space. So, we report a simple neurolysis technique which can inject drugs directly to nerve roots and intervertebral discs at anterior epidural space through the caudal approach using conventional neurolysis devices.