Purpose
This study was conducted to identify risk factors predicting the loss of cervical lordosis (LCL) in patients with multilevel ossification of the posterior longitudinal ligament (OPLL) following laminoplasty. Material and Methods: We conducted a retrospective analysis of data from patients who underwent laminoplasty at Chonnam National University Hospital between January 2013 and December 2022. Various radiological parameters and clinical outcome measures were collected perioperatively. Patients were divided into 2 groups according to the severity of LCL. We examined preoperative radiological parameters associated with LCL.
Results
We analyzed data from 109 patients (92 men and 17 women; mean age, 60.31±10.80 years). A higher T1 slope (odds ratio [OR], 1.420; p<0.001) and a lower extension ratio (OR, 0.883; p=0.019) were associated with a higher risk of LCL. T1 slope was shown to be an excellent predictor of LCL, with a cut-off value of 28° (p<0.001, area under the curve=0.918). Also, The T1 slope and extension ratio were statistically significant correlated with clinical outcomes.
Conclusions
T1 slope and extension ratio were significantly associated with LCL in patients with multilevel OPLL following laminoplasty. The cut-off value for the T1 slope was 28°, and the cut-off value for the extension ratio was 33. Therefore, in multilevel OPLL patients with a T1 slope exceeding 28° or an extension ratio below 33, a warning regarding the potential LCL should be given before performing cervical laminoplasty.

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.

Numerous improvements in minimally invasive spine surgery (MISS) have been made during the past decade. Classic treatment methods have reserved surgical intervention for trauma patients with neurological compromises or instability. When used in thoracolumbar spine trauma management, MISS should achieve the similar results as classic treatment with less morbidity.(1) In the past decade, minimally invasive surgical (MIS) techniques for spine surgery have been increasingly used. The goal of minimally invasive surgery is to decrease surgical morbidity through decreased soft-tissue dissection providing similar structural stability as classic techniques. An increasing number of studies is reporting good clinical and radiographic outcomes with MIS techniques. However, the literature is lacking high-quality evidence comparing these newer techniques to classic treatments. In the future, development of techniques can expand the indications and treatment possibilities in spine trauma treatment. We reviewed the current literatures to clarify the indications of minimally invasive techniques with spinal trauma.

Many techniques have been introduced and performed, with different strengths and benefits. The lateral lumbar interbody fusion techniques (direct lateral lumbar interbody fusion [DLIF] and oblique lateral interbody fusion [OLIF]) have yielded good results for elderly patients. These are useful options for elderly patients with high risk of complications with traditional approaches.

Purpose
To find the factors that affecting surgical outcome after vertebroplasty and kyphoplasty in osteoporotic compression fracture.
Materials and Methods
Pre-operative, post-operative, technical, radiological factors of patients who diagnosed osteoporotic compression fracture and treated with vertebroplasty or kypholasty during from January 2008 to December 2010, were compared by outcomes that acute and chronic back pain, refracture rate and maintenance of the reduction of body height.
Results
The period of acute pain after the operation was less than 3 days in groups of trauma( p=0.0262) and hospital treatment(p=0.0113) before the operation as pre-operative factors. When it comes to technical factors, the cases of vertebroplasty(p<0.0001), injection of cement(p=0.0053), the case without leakage of cement(p=0.007) and the case being under anesthesia (p<0.005)achieved statistical significance. In the groups who got conservative treatment less than 1 week (p=0.0119) and local anesthetics(p=0.0246), refractures occurred many times. The groups of non-trauma(p=0.0105), having had more than 30% compression(p=0.0244) and the group that prescribed bisphosphonate(p=0.0286) statistical significantly maintained restoration.
Conclusion
Conservative treatment in the hospital for more than 1 week before the operation, operation being under anesthesia and intake of bisphosphonate after the operation put positive effects on the outcome of vertebroplasty and kyphoplasty.