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.

Intraoperative blood loss volume increases due to soft tissue injury or excessive traction generated by extensive approach including posterior fusion or posterior lumbar interbody fusion, leading to the occurrence of complication and delay in postoperative recovery, On the other hand, MI-TLIF minimizes injuries in soft tissue and surrounding muscle by approaching between multifidus muscles and longissimus dorsi after separating them, and reaching intervertebral disc from lateral vertebral foramen. The advantages of this surgical procedure are minimization of muscle or soft tissue injuries incurred by lateral approach, reduction of surgically related muscle damage, and decrease of postoperative blood loss. However, The size of cages are limited by transforaminal approach in MI-TLIF, eventually it could be difficult to maintain the correction of deformity(disc height, segmental and lumbar lordosis). Recently, DLIF(Direct lateral interbody fusion) is developed to improve the disadvantages of TLIF. DLIF allows to insert larger cage than TLIF, as a result larger cage have a advantage to maintain correction of disc height and lordosis because it can support both apophyseal rings of endplates. However, Transpsoas approach is essential for DLIF, so we need to understand the anatomy lumbosacral plexus in psoas, because nerve injury during the transpsoas approach is the most common and potentially the most devastating complication of the DLIF procedure. And many authors reported that various frequency of nerve injury according to surgeon’s skill. Therefore, surgeon’s skill and accurate understanding about the procedure are important factors to prevent the complications of DLIF.

Purpose
A surgical treatment has been preferred in patients with unstable lumbar spine fracture-dislocation with incomplete paraplegia as it does not cause further nerve injury by regenerating and maintaining the shape of the spinal canal via the accurate reduction of fracture, and prevents additional complications by preventing neurovascular injury that secondarily occurs.¹⁾ However, the surgical treatment may be delayed or even impossible in patients with hemodynamic unstable state caused by an emergent concurrent injury. Accordingly, Stage operation was conducted on patients with unstable lumbar spine fracture-dislocation with incomplete paraplegia who had a difficulty in undergo immediate reduction and decompression due to hemodynamic unstable state caused by other concurrent injuries.
Methods
Postural reduction and minimal invasive percutaneous pedicle screw fixation L1-4 were conducted as a first stage operation, and L2-3 partial laminectomy, discectomy, and posterior fusion were then conducted as a second stage operation by applying the concept of stage operation in the department of spinal surgery.
Results
The first stage operation had a blood loss of 150cc and an operation time of 58 min. Compared to motor grade 3 shown in preoperative status, motor grade 4 was shown in L3 level or lower in a postoperative physical examination. The second stage operation was conducted two weeks later. It had an operation time of 90 min and a blood loss of 500cc. no neurologic change was further found.
Conclusion
Stage operation was conducted on patients with hemodynamic unstable state. Postural reduction and minimal invasive percutaneous pedicle screw fixation were conducted as a first stage operation to achieve the immediate reduction and stability of fracture and dislocation and the improvement of neurologic deficits. Subsequently, decompression or fusion was conducted as a second stage operation under stable systemic status for through and accurate operation.

Purpose
The purpose of this study is to decrease the frequency of the perioperative complication and improve the clinical outcomes of multilevel lumbar degenerative disease by multilevel minimally invasive transforaminal lumbar interbody fusion.
Materials and Methods
317 patients(Minimally invasive transforaminal lumbar interbody fusion : 161, Conventional open surgery : 156) were followed up for more than 1 year. The age of each patient, the amount of intraoperative blood loss, the postoperative drainage, the transfusion requirement, surgery time, using of Intensive care unit, ambulation day, admission day and perioperative complications were investigated and analyzed.
Results
Minimally invasive transforaminal lumbar interbody fusion was found to have a less blood loss, less using of Intensive care unit. And as the levels of union increase, disparities were increased(p<0.05). But, surgery time of Minimally invasive transforaminal lumbar interbody fusion was longer, and as the levels of union increase, disparities were increased(p<0.05).
Conclusions
Multilevel Minimally invasive transforaminal lumbar interbody fusion can be the better way, If surgery time of Multilevel Minimally invasive transforaminal lumbar interbody fusion can be reduced.