Lumbar degenerative scoliosis (LDS) has been increased with increased aging population. The conventional surgical treatment method of LDS was posterior decompression followed by lumbar fusion. However, these surgeries usually require long-level fusion with increased risk of much bleeding and perioperative morbidity especially in old patients. The correction of sagittal or coronal imbalance is also important in the surgical treatment of LDS, thus osteotomy may be sometimes required. Direct lateral interbody fusion (DLIF) has been introduced as a part of minimally invasive surgery. With DLIF technique, the stenotic canal or foramen can be decompressed indirectly without laminectomy and the lumbar lordosis can be restored through the disc height distraction. Recently, DLIF has been also used for the surgical treatment of LDS. With use of DLIF for LDS, it has been reported that the lumbar lordosis and coronal curve angle were restored and the clinical outcome was also favorable without significant surgical morbidities. The lateral approach sometimes carries the risk of the lumbar plexus palsy or vessel injuries. DLIF can be a good alternative to the posterior fusion technique for the treatment of LDS in that it can minimize the perioperative morbidity and it can also restore the sagittal or coronal radiographic profiles effectively.

Extreme lateral interbody fusion (XLIF) and direct lateral interbody fusion (DLIF) are novel minimally invasive transpsoas approaches to the lumbar spine for performing fusions. Advantages of DLIF include easier technique, faster recovery, minimal complication, high fusion rate, and possibility of achieving better alignment. Many previous reports have evaluated outcomes of DLIF. The authors described surgical procedure of DLIF and reviewed clinical outcomes, radiological outcomes, and complications from various literatures. In conclusion, the DLIF seems to be a valuable minimally invasive surgical tool for the fusion in patients with various diseases, including degenerative disc disease, instability, stenosis, scoliosis, tumor, infection, and adjacent segment degeneration.

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
The purpose of the study was to investigate the effect of obesity on the accuracy of percutaneous pedicle screw placement.
Materials and Methods
We performed a retrospective analysis on the first 89 patients undergoing minimally invasive lumbar fusion with percutaneous pedicle screw placements for the treatment of degenerative lumbar spinal disorder. Based on patient’s body mass index (BMI), patients were divided into 3 groups: group 1 – normal weight (BMI<25, 38 patients, 157 screws); group 2 – overweight (25≤BMI<30, 29 patients, 124 screws); group 3 – obese (BMI≥30, 22 patients, 89 screws). Using postoperative computed tomography (CT) scans, the position of placed screws to the pedicle or anterior body perforation was evaluated using the following grading method: Grade A, completely in the range without pedicle cortex violation; Grade B, pedicle wall violation<2 mm; Grade C, pedicle wall violation 2 to 4 mm; and Grade D, pedicle wall violation>4 mm.
Results
Among the 370 pedicle screws, 308 screws (83%) were perfectly placed within the pedicle. Among the 62 misplaced screws, 45 screws were grade B pedicle breaches (73%, 45/62), and 45 screws were misplaced in lateral direction (73%, 45/62). 36 screws (10%) perforated the anterior vertebral cortex. Twenty eight screws were misplaced in overweight group, 12 screws in obese group, and 22 screws in normal weight group. With the number of screws available, subgroup analysis did not reveal a significant difference in the grade (p=0.10) or the direction (p=0.97) of pedicle breaches among groups.
Conclusion
Our data suggest that obesity does not affect the accuracy of percutaneous pedicle screw placement. We do not hesitate or deny the surgery because of patient’s heavy body habitus, which seems to be a apparent benefit of minimally invasive spinal surgery.

Lumbar cortical screw, an alternative to the traditional pedicle screw, has more cranially and laterally oriented trajectory within pedicle after being anchored in the pars interarticularis. Such cortical trajectory can lower the risk of nerve root impingement by traditional pedicle screw and reduce the iatrogenic soft tissue damage that occurs with muscle stripping and lateral retraction for traditional trajectory. In addition, lumbar cortical screw proved equivalent pullout strength compared with the traditional pedicle trajectory despite its shorter and smaller screw design. However, clinical trial is still in the beginning stage, and further clinical studies are required to clarify the actual outcome of the lumbar cortical screw.

Objective
Peridural fibrosis may cause failed back syndrome and the presence of fibrosis renders reoperations risky. Therefore, preventing the adhesion of scar tissue to the dura and nerve root is one of the issues in spinal surgery. Thus, the purpose of this study is to evaluate and compare the efficacy and the safety between two anti-adhesive agents, BNCH-202 (Korea BNC Inc, Daegu, Korea) and Guardix-SOL (Hanmi, Seoul, Korea).
Methods
Sixty eight patients were enrolled in this study. To evaluate and compare the efficacy in preventing epidural adhesion formation and the safety in human laminotomy models, the two barriers tested were either BNCH-202 or Guardix-SOL (gel/film combination). Clinical evaluation was performed at 0, 6 and 12 weeks to assess pain and functional outcome. The patients were also assessed radiographically with postoperative magnetic resonance imaging (MRI) to evaluate the presence of perinueral scar and adhesion.
Results
There was no statistically significant difference between two biologic barriers in terms of the safety issue, clinical and radiological efficacy. There were no significant differences between the BNCH-202 group and the control group on the preoperative ODI and VAS scores. In general, the ODI and VAS scores decreased in both groups at all the time points. At the 6 week and 12 week time point, the VAS scores for back pain/ leg pain and the ODI scores in both groups were lower than the preoperative score in each group (P<0.01). And at the 12-week time point, the peridural scar scores were assessed in both groups. The mean value of the peridural scar score in BNCH-202 group was not inferior to the mean value of that in Guardix-SOL group.
Conclusion
The results demonstrated that BNCH-202 gel is as effective as Guardix-SOL in reducing posterior dural adhesions in the spine with no apparent safety issues. It can improve patients’ postoperative clinical outcome.