Purpose
of study: The purpose of this study is to evaluate the effect of blow flow originated from transverse process after posterolateral lumbar fusion (PLF) in rabbit.
Materials and Methods
Bilateral PLFs using autogenous iliac bone, 3 mm³ on each operated site, were done in 20 rabbits. In group A, PLFs were done on the decorticated transverse processes. In group B, no decortications were done before PLFs. In group C, PLFs were done after application of Bone wax^® on the transverse processes. In group D, PLFs were done after application of Surgicel^® on the decorticated transverse processes. The five rabbits and 10 operated sites were used in each group. The computed tomography (CT) was done for each group at postoperative 6 and 12 weeks. To evaluate bony union, the status of PLF was divided into ‘union’ and ‘nonunion’ . And, the volumes of grafted bones were counted at each follow up period in each group. The values were analysed statistically.
Results
The union rates of PLFs were observed 90% in group A, 80% in group B, 20% in group C, 70% in group D. Group C showed lowest union rate than other group with statistical signification (p<0.05). The of volumes of grafted bones at postoperative 6 weeks were calculated to 2.8±0.2 mm³ , 2.6±0.3 mm³ , 1.6±0.8 mm³ , 1.8±0.7 mm³ in group A, B, C, D, retrospectively. At postoperative 12 weeks, the volumes were checked as 2.1±0.6 mm³ , 1.8±0.5 mm³ , 1.2±0.9 mm³ , 1.6±0.4 mm³ in group A, B, C, D, retrospectively. The volumes of grafted bones were checked in order to group A, B, D, and C at 6 and 12 weeks postoperatively. And the volumes in group C were mostly reduced at postoperative 6 and 12 weeks (p<0.05). In group C and D, there were statistically significant reduction in volumes of grafted bones at each follow up period comparing to group A and B (p<0.05).
Conclusions
In the PLF of rabbit, the transverse process-grafted bone contact and blood flow originated from transverse process may play major roles in bony union. Among them, the blood flow originated from transverse process might be more important than the bony contact in the union process of PLF.

Purpose
To compare the difference of cervical alignment between cervical lateral radiograph and whole-spine lateral radiograph by the effects of radiographic position and to assess the effect of the shoulder flexed position to cervical lordotic curvature and head position.
Materials and Methods
We retrospectively evaluated 43 asymptomatic adult patients who were taken horizontal gazing standing cervical and whole-spine lateral radiograph simultaneously from Sep. 2008 to Dec. 2009. Cervical lateral radiograph was taken with the arms extended and hand gently clasped on both side and whole-spine lateral radiograph was taken in the position that subject were relaxed standing with fists-on-clavicles position. Cervical sagittal alignment were analyzed the following parameters. (1) Gore angle (GA, C2-7 angle); (2) Cobb angle (CA, C2-7 angle); (3) translation distance (TD, distance of C2 compared with vertical line through the posterior-inferior body of C7); (4) McGregor angle (MA, angle between McGregor line and horizontal line).
Results
The mean of GA and CA in cervical radiograph were -12.64° and -9.96°, whereas -7.12° and -4.98° in wholespine radiograph. The mean TD and MA were in cervical radiograph were 16.95mm and 7.15°, whereas, 14.97mm and 6.54° respectively in whole-spine radiograph.
Conclusion
Our study showed the significant differences of cervical alignment and head position between standing cervical lateral and whole-spine lateral radiograph. The radiographic posture of whole-spine lateral radiograph with horizontal gazing and fists-on-clavicles position make cervical alignment and head position less lordotic and posterior translation compared to cervical radiograph.

Purpose
Higher viscous cement can be injected through larger-diametered tubes with lower pressure. The lower the cement modulus is, the less the stress-transfer would be. The lower-pressure percutaneous vertebroplasty with blood-mixed cement(LP-PVP^blood ) was devised to overcome technical problems in conventional percutaneous vertebroplasty(C-PVP). We would like to prove the validity of technical modifications to increase viscosity of cement being injected and reduce final modulus of cement.
Methods
Nineteen C-PVPs, 51 kyphoplasty (KPs), 23 LP-PVPs and 70 LP-PVP^blood s were analyzed in radiologic point of view. The successful cases with sufficient cement volume(≥ 5ml) were also analyzed as a subgroup.
Results
Asymptomatic cement leakage(CL) showed a similar tendency in LP-PV^blood (17.1%) compared to other groups(21.1~27.5%, p=0.514), even though the injected cement volume in LP-PVP^blood (6.9ml) was much more than that of C-PVP(3.5ml, p=0.000). Vertebral height restoration(VHR) was significantly higher(11.7%) than C-PVP(4.7%, p=0.024). Vertebral body subsidence(VS) was less in KP(1.1%) than others(2.1~5.9%, p=0.000). But, adjacent vertebral compression fractures(VCFs) happened more frequently in KP(15.7%) than others (0~5.3%, p=0.001). In subgroup analysis, the rates of successful cases were significantly higher in LP-PVP^blood (85.7%) than in C-PVP(5.3%, p=0.000). CLs and VHRs showed no significant differences. VS was significantly less in KP(1.0%, p=0.000) but adjacent VCF developed more frequently in KP(21.1%) than LP-PVP^blood (0%, p=0.001).
Conclusions
The LP-PVP^blood which stands for larger diameter tubes for injecting sufficient volume of higher viscous cement and more interdigitation by omitting balloon and lower modulus blood-mixed cement was appraised to reduce risk of cement leakage than C-PVP and decrease stress transfer to adjacent vertebrae than KP.

We reviewed literatures relating to minimally invasive lateral lumbar interbody fusion for the treatment of adult degenerative spinal deformity. Most of literatures were retrospective case series with a small numbers of patients. A prospective multicenter study was published in two separate papers. This procedure was effective in treating the coronal deformity. On the other hand, restoring the sagittal plane remains an issue. Pseudarthrosis was problematic, especially in the cases without use of the human recombinant bone morphogenetic protein-2 (rhBMP-2) and bilateral pedicle screw fixation. Temporary sensory deficits and transient leg weakness was the most common complication after lateral lumbar interbody fusion. Careful patient selection is important for the application of lateral minimally invasive techniques for adult degenerative scoliosis.

In this article, research trend of biomaterials for spinal disease was summarized with an emphasis on molecular therapy for spinal cord injury. Cytokines, cell therapy and biomaterials are future perspectives for treatment of spinal cord injury. But there is no promising result in clinical trial setting so far. Adult stem cells, embryonal stem cells and recently iPS(induced pluripotent stem) cells are widely investigated for cell therapy of spinal cord injury. But ideal cell is not yet determined. Research of biomaterials for cord injury is in the beginning. There is no conclusive data of stem cell therapy in cord injury in terms of effectiveness of improving neurologic deficits. But results of clinical trial showed the feasibility and safety of cell therapy. The combined treatments with cytokines, cells, and biomaterials will be a new modality of biological treatment in spinal cord injury.

Chronic low back pain is a common cause of disability causing major socioeconomic consequences. Recent advances in disc biology and tissue engineering techniques enable a new emerging field of biologic treatments for degenerative disc disease. These new treatment modalities aim to achieve structural and functional restoration of the degenerated discs by introducing protein, cells, genetic modifications of resident disc cells or exogenous cultured cells, and use of biomaterials. So far, these techniques have been successfully applied to treat degenerated discs in preclinical setting, including in vitro or in animal studies. Application of these treatment modalities for degenerative disc disease should be individualized according to the degree of disc degeneration. For the successful application in clinical field, the biologic treatment should achieve the functional restoration of the disc, resulting in pain regulation.