Background
Minimally invasive transpsoas or antepsoas lateral lumbar interbody fusion (MI-LLIF) has been reported as an effective surgical option for various lumbar diseases. Many researchers reported high fusion rate and clinical excellence of LLIF with the use of bone morphogenic protein (BMP). However, there have been paucity of studies regarding LLIF without the use of BMP. Therefore, this study aimed to analyze radiologic and clinical results of patients who underwent minimally invasive lateral lumbar interbody fusion without the use of BMP. Furthermore, a further analysis was conducted regarding the frequency of cage subsidence and its impact on the radiologic and clinical outcome.
Materials and Methods
Fifty patients and 109 levels treated by MI-LLIF with postoperative follow-up of at least 2 years were included. Radiologic evaluation included intervertebral disc height, segmental lordosis, lumbar lordosis, fusion rate, cage subsidence grade, and the bone mineral density. Radiologic fusion was determined by modified Bridwell’s grade, and cage subsidence by Marchi’s grade. Clinical outcome was evaluated by VAS of low back pain (LBP) and leg pain, and ODI score. The above clinical and radiologic variables were analyzed statistically for comparison of cage subsidence and nonsubsidence groups.
Results
There were 20 male and 30 female patients with the average age of 69 years. Average follow-up period was 29.6 months(24-42 months). Graft material used for PEEK cage was autogenous bone only in 9 levels, autogenous bone and DBM in 19 levels, and DBM only in 81 levels. Twelve patients received surgery on 1 level, 20 patients on 2 levels, 17 patients on 3 levels, and 1 patient on 4 levels, respectively. Operated levels were L1-2 in 7 cases, L2-3 in 27, L3-4 in 41, and L4-5 in 34, respectively. Mean low back pain (LBP) VAS decreased from preoperative 5.5 to 2.2 at the final follow-up, leg pain from 6.1 to 1.7, and ODI score from 25.6 to 13.7, with statistical significance (p<0.001). Mean disc height increased from preoperative 5.9 mm to postoperative 11.5 mm, and subsequently decreased to 9.6mm at the final follow-up. Average lumbar lordosis increased from preoperative 18.6 degrees to postoperative 37.0 degrees, and 35.9 degree at final follow-up. Radiologic union rate was 90.8%. Cage subsidence was observed in 6 levels (5.5%) on immediate postoperative radiographs; and in 20 levels (18.3%) at final follow-up. Comparison between cage subsidence and non-subsidence groups revealed no significant difference in age and BMD. Immediate postoperative segmental lordosis was considered as a risk factor of cage subsidence (p=0.005, odds ratio 0.813, CI 0.703~0.940). Furthermore, the preoperative and the final follow-up measurement of disc height, VAS score of LBP and leg pain, and ODI score were not different between the two groups. However, pseudoarthrosis rate was higher in subsidence group.
Conclusions
Minimally invasive LLIF was an effective surgical option with high fusion rate even without the use of BMP. Although cage subsidence also increases the frequency of pseudarthrosis, it does not significantly deteriorate the lumbar lordosis correction and clinical outcome.

Oblique lumbar interbody fusion (OLIF) is one of surgical techniques for patients with spondylolisthesis, but an insertion of cage at an ideal location (anterior 1/3 of disc space) is challenging for patient with high grade spondylolisthesis, because vertebra are not aligned. Recently, a technique of simultaneous insertion of pedicle screw and rod system from the back of patient and insertion of cage via retroperitoneal route from the front of patient is possible by using spinal navigation system (OLIF-360). The author present a case and surgical technique of simultaneous re-alignment of high-grade spondylolisthesis at L4-5 and insertion of interbody cage by using OLIF-360. An intervertebral cage was inserted at the ideal location after re-alignment of spondylolisthesis with OLIF-360. Postoperative images showed re-aligned vertebra and successful decompression. The specific utilization of OLIF-360 has not been underscored yet.

Introduction
A spondylitis developed after a surgery has been usually treated with drainage and curettage through anterior approach and autoiliac strut bone graft. However, anterior support with titanium cage combined with posterior pedicle screw fixation has been attempted. Implanting a foreign material is usually prohibited at an active pyogenic infection site. We tried to prove the usefulness of chip bone graft with metal cages in surgical treatment of spondylitis developed in posterior lumbar intebody fusion cases.
Materials and Methods
This is a retrospective study. The patients who received posterior lumbar interbody fusion (PLIF) between Jan. 2007 and Dec 2017 and had a spondylitis around the cage were reviewed. There were 1,831 PLIFs during the study period. There were 32 cases of surgical site infection and 20 of them were spondylitis around the cage. Ten out of the 20 cases had a revision surgery. All implants removal, drainage and curettage were done and interbody bone graft and pedicle screw re-fixation was done simultaneously. Five cases used autoiliac strut bone (Group I) and the other 5 cases used titanium cage and autoiliac chip bone (Group II) as interbody graft materials. The demographic, diagnostic and microbiological characteristics were investigated and the results of treatment were compared between the two groups.
Results
The diagnosis of infection was made at 282.0±106.1 (180~410) days in group I and 209±118.4 (75~335) days in group II after the PLIF. All cases had neither general fever nor local manifestations like heating and redness etc. All patients had back pain, however, only 2 cases of group II had neurological symptoms. C-reactive protein (CRP) level was elevated at 2 weeks from the PLIF in all cases (p<0.001). All cases had implant loosening at the time of their diagnosis. There was no failure of infection control. All cases showed normalization of CRP and radiological interbody fusion. The final Oswestry disability index (ODI) showed no difference between the two groups. ODI improved from 54.6±11.5 to 42.2±6.8 in group I (p=0.095) and from 63.6±6.9 to 44.8±11.7 in group II (p=0.025).
Conclusion
For the surgical treatment of spondylitis that were developed in PLIF, a comprehensive one stage operation that comprised all implants removal, drainage and curettage followed by simultaneous intebody bone graft with metal cages and pedicle screw re-fixation was useful to control the infection.

A 77-year-old female suffering from severe degenerative scoliosis, spinal stenosis and lumbar disc herniation underwent Direct lateral lumbar interbody fusion (DLIF) at L2-4. On the 3rd postoperative day, she complained of severe back pain without any trauma history. Simple radiograph revealed L3 vertebral fracture and cage subsidence. Pain was subsided after conservative treatment including TLSO and medication. Radiographic union was achieved at fractured vertebra after 3 months. Solid fusion was observed at operated level after 6 months. Patient has visited our clinic without any pain. DLIF is one of novel minimally invasive spine procedures available today. It is designed to maximize benefits and minimize risks of other traditional techniques such as anterior approach and posterior approach. However, there can be some risk of cage subsidence and vertebral fracture after DLIF. Therefore, care should be taken to avoid cage subsidence during the operation.

Objectives
To evaluate the effectiveness of a prototype plate and cage device (PCB) in cervical spine disease.
Summary of Background
Data: Several Cage-Screw implants have recently been developed to avoid cervical platerelated complications.
Methods
A total of 34 patients with cervical disc protrusion who underwent PCB implantation between 2004 and 2007 were included in the study. There were 22 males and 12 females with a mean age of 49.9 years (range: 30 to 62 years). Odom’s Criteria were evaluated in all patients for a minimum follow-up period of 1 year (mean 24.6 months). Radiographic evaluation was performed to assess the status of fusion, intervertebral disc height, cervical lordosis and segmental kyphosis.
Results
In general, there were 20 excellent cases, 10 good cases and 4 fair cases according to Odom’s Criteria. In terms of radiological results, the height of intervertebral disc space was measured three different times, as follows: pre-operation, mean 6.07 mm; post-operation, mean 9.52 mm; last follow-up, mean 8.74 mm. No patients showed segmental instability on flexion-extension view at the last follow-up appointment. There were no cases of screw back out or device failure and no donor site morbidity.
Conclusion
PCB implant for degenerative cervical disease may restore intervertebral disc space and lordotic angle of the cervical spine without significant complications.