Purpose
Thoracolumbar vertebral compression fractures (VCFs) are a leading cause of kyphosis and related biomechanical complications, often resulting in chronic back pain and reduced function. Balloon kyphoplasty has been widely used as a minimally invasive intervention to provide pain relief and restore vertebral height. The SpineJack system is a relatively novel technique that introduces mechanical distraction, offering potentially enhanced vertebral restoration. This study aims to compare these two effective treatments for thoracolumbar fractures.
Materials and Methods
This study analyzed 30 patients with thoracolumbar VCFs surgically treated, using the Spine-Jack system (n=10) or balloon kyphoplasty (n=20). Back pain was evaluated as VAS pain score and functional disability was assessed with Oswestry Disability Index (ODI) preoperatively and immediately postoperatively. Radiological outcomes were measured on plain lateral X-rays, including vertebral height restoration, segmental kyphosis angle, and sagittal vertical axis (SVA). Complications, such as cement leakage and adjacent vertebrae fractures, were recorded. Continuous variables – with t-tests and categorical variables- with chi-square tests, were analyzed. P-value less than 0.05 was considered statistically significant.
Results
Both the Spine-Jack system and balloon kyphoplasty were effective in reducing back pain and improving patients’ function, with significant improvements in VAS and ODI scores. However, the Spine-Jack system demonstrated superior vertebral height restoration (85% vs. 72%, p=0.03) and segmental kyphosis angle correction (12° vs. 9°, p=0.032) when compared to balloon kyphoplasty. Complication rates were all low and comparable between the two groups.
Conclusions
Although the Spine-Jack system and balloon kyphoplasty are all effective for thoracolumbar VCFs, the Spine-Jack system offered superior radiological outcomes in selected cases. Further studies may explore their complementary roles in managing thoracolumbar VCFs.

Purpose
The impact of skeletal muscle mass and bone mineral density (BMD) on frailty after osteoporotic vertebral fractures (OVFs) remains unclear. This study aimed to assess the interplay between frailty, skeletal muscle mass, and bone mineral density in OVFs.
Materials and Methods
A total of 66 patients with osteoporotic vertebral compression fractures were enrolled. We collected clinical and radiological data, including age, body mass index (BMI), frailty index, and parameters such as lumbar lordosis, thoracic kyphosis, skeletal muscle mass, and BMD. We then analyzed the relationships between frailty and these variables.
Results
The mean age, BMI, BMD T-score, skeletal muscle mass, and frailty index were 78.0±7.8 years, 22.3±3.3 kg/ m², -3.59±0.96, 37.84±6.24 kg, and 2.59±1.08, respectively. Of the 66 patients, 14 (21.1%) were frail prior to fracture, while 37 (56.1%) were frail after fracture, indicating a worsening frailty status. Specifically, 23 patients (34.8%) transitioned from pre-frail to frail following their fracture and had both lower BMD (T-score: -3.7±0.93) and lower skeletal muscle mass (35.74±3.83 kg). Frailty was negatively correlated with BMD (r=-0.28, p=0.02), while BMD was positively correlated with skeletal muscle mass (r=0.29, p=0.02). OVFs were positively correlated with frailty (r=0.33, p=0.01), especially in terms of fatigue (r=0.31, p=0.01) and ambulation (r=0.21, p=0.01).
Conclusions
In patients with osteoporotic vertebral fractures, decreased muscle mass and low BMD appear to exacerbate frailty. Furthermore, frailty may be both a contributing and a resulting factor in the development of osteoporotic vertebral fractures.

Advanced imaging technologies have revolutionized the diagnosis and management of spinal pathologies by providing superior precision and efficiency. Modalities such as PET-CT, SPECT, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) offer unique insights into the metabolic, structural, and functional aspects of spinal diseases, enabling better differentiation of lesions, improved surgical planning, and early detection of pathological changes. Furthermore, the integration of artificial intelligence (AI) has enhanced imaging workflows by enabling automated analysis, prediction of clinical outcomes, and segmentation of spinal structures. Despite these advancements, challenges such as technical limitations, high costs, and ethical concerns, including issues of data privacy and AI-generated inaccuracies, hinder widespread adoption. This review explores the clinical applications, limitations, and future directions of these emerging technologies, highlighting the need for multidisciplinary collaboration and large-scale research to standardize protocols and optimize patient outcomes. The seamless integration of advanced imaging and AI represents a transformative potential for improving diagnostic accuracy and treatment efficacy in spinal care.

Objective
To investigate the utility of a deep learning model in diagnosing traumatic lumbar fractures on computed tomography (CT) images.
Summary of Background
Data: CT scans are widely used as the first choice for detecting spinal fractures in patients with severe trauma. Although CT scans have high diagnostic accuracy, fractures can occasionally be missed. Recently, deep learning has been applied in various fields of medical imaging.
Methods
CT images from 480 patients (3695 vertebrae) who visited a level-one trauma center with lumbar fractures were retrospectively analyzed. The diagnostic results were confirmed by two experienced musculoskeletal radiologists and one experienced spine surgeon using magnetic resonance imaging (MRI). Deep learning networks were employed for diagnosis, with 425 cases used for training and 55 cases for testing. Sensitivity, specificity, accuracy, and the area under the receiver operating characteristic curve (AUROC) were calculated to evaluate diagnostic performance.
Results
The model successfully identified 107 out of 129 vertebrae with fractures, achieving a sensitivity of 82.95%, a specificity of 93.24%, an AUROC of 0.936, and an overall accuracy of 88.45%.
Conclusions
This study demonstrated that the deep learning model showed high accuracy in diagnosing traumatic lumbar fractures. This approach has the potential to assist spine specialists, radiologists, and trauma care experts. Further validation is needed to determine its effectiveness in clinical settings.

Objective
Postoperative urinary retention (POUR) is a common complication following lumbar spine surgery, significantly affecting functional recovery and Enhanced Recovery After Surgery (ERAS) protocols. POUR can lead to bladder overdistension, infections, prolonged hospital stays, and long-term detrusor dysfunction. Postoperative delirium (POD) can impair cognitive function and mobility, potentially triggering or exacerbating POUR. This study aims to investigate whether POD serves as an independent risk factor for POUR and to analyze other contributing factors to provide clinical management strategies.
Materials and Methods
A retrospective cohort study was conducted involving 420 patients who underwent lumbar spine surgery at a single tertiary medical institution between March 2021 and February 2024. POUR was defined as a post-void residual (PVR) bladder volume ≥300 mL measured via bladder ultrasound or requiring catheter reinsertion due to urinary retention. POD was diagnosed within 72 hours postoperatively using the Confusion Assessment Method (CAM) and was classified into three subtypes: hyperactive, hypoactive, and mixed. Multivariate logistic regression analysis was employed to identify the relationship between POD and POUR, with sensitivity and specificity assessed through Receiver Operating Characteristic (ROC) curve analysis.
Results
Among 420 lumbar spine surgery patients, 44 (10.5%) experienced POD. Of these, 16 (36.4%) were classified as hyperactive, 20 (45.5%) as hypoactive, and 8 (18.2%) as mixed type. POUR occurred in 28 of the POD patients (63.6%) compared to 71 of 376 patients without POD (18.9%), demonstrating a statistically significant difference (p<0.001). The analysis of POUR incidence by POD subtype revealed rates of 62.5% (10/16) for hyperactive POD, 60.0% (12/20) for hypoactive POD, and 75.0% (6/8) for mixed POD. Patients with mixed POD showed the highest POUR incidence, with a significant difference compared to hyperactive and hypoactive POD (p<0.05). Multivariate logistic regression analysis identified POD as an independent risk factor for POUR, increasing the likelihood by approximately 3.7 times (Odds Ratio, OR: 3.71; 95% Confidence Interval, CI: 1.95–7.06; p<0.001). Among POD subtypes, mixed POD presented the strongest association with POUR, increasing the risk by 4.8 times (OR: 4.84; 95% CI: 2.10–11.15; p<0.001). Hyperactive and hypoactive POD were also significant risk factors, increasing POUR risk by 3.0 times (OR: 3.04; 95% CI: 1.45–6.35; p=0.003) and 3.5 times (OR: 3.48; 95% CI: 1.69–7.19; p=0.001), respectively.
Conclusions
This study confirms that postoperative delirium (POD) is an independent risk factor for postoperative urinary retention (POUR) in lumbar spine surgery. The occurrence and subtype of POD significantly influence POUR incidence, with mixed POD presenting the highest risk. These findings highlight the importance of early diagnosis and prevention of POD as a strategy to effectively reduce POUR. A multidisciplinary approach integrating POD and POUR management could optimize postoperative outcomes and improve patient recovery.

Objective
To investigate stiffness-related disability (SRD) following surgical treatment in adolescent idiopathic scoliosis (AIS) patients particularly with respect to the lowest instrumented vertebra (LIV).
Summary of Background
Extensive spinal fusion inevitably results in loss of mobility which may induce SRD during activities of daily living. Few studies have examined SRD after surgical correction for AIS.
Methods
Patients who underwent surgical correction for AIS between 2014 and 2021 and were followed up for two years were included. The degree of SRD was evaluated using the Stiffness-Related Disability Index (SRDI) which consists of four categories, each containing three questions, giving a total of 12 components of the questionnaire. The SRDI scores were compared according to the (LIV) levels. Correlation analysis was performed to examine the relationship between the SRDI and legacy health-related quality of life (HRQOL) measurements.
Results
This study included 174 patients (47 males, 127 females) with a mean age of 13.8 years. Among the 12 items of the SRDI, the scores of nine items showed a significant increase after surgery. The total sum of the SRDI scores also significantly increased after surgery. Pearson correlation analysis showed that the SRDI scores were significantly correlated with ODI (Oswestry disability index), nearly all domains, and the total sum of SRS-22 (Scoliosis Research Society-22 questionnaire), and SF-36 (Short Form 36 health questionnaire). No differences in the SRDI score were found among cases with the LIV between T12 and L3. However, The SRDI scores of patients with LIV at L4 were significantly higher than those of patients with other LIV levels. .
Conclusions
Various degree of SRD occurred after spinal fusion for AIS. The SRDI significantly correlated with the HRQOL measures. The SRDI score was highest in patients with the LIV at L4 compared to those with other LIV levels.

Background
This study aims to assess the clinical and radiographic outcomes of biportal endoscopic lumbar discectomy compared to microscopic lumbar discectomy in obese patients with lumbar herniated discs. Previous research has established a positive correlation between operation time and estimated blood loss in obese patients undergoing microscopic lumbar discectomy, based on an increase in body mass index. However, no studies have specifically examined the outcomes of biportal endoscopic lumbar discectomy in this patient population. Therefore, this study seeks to fill this research gap and provide valuable insights into the effectiveness of these two surgical approaches for obese patients with lumbar herniated discs.
Methods
This retrospective multicenter study analyzed and compared clinical and radiological data from 48 obese patients with a body mass index (BMI) greater than 30 kg/m² who underwent either microscopic or biportal endoscopic lumbar discectomy. The study assessed clinical outcomes using the visual analog scale (VAS), Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D) scores. Radiological data were obtained through magnetic resonance imaging (MRI) scans.
Results
The study included a total of 48 patients, with 31 patients undergoing microscopic discectomy and 17 patients undergoing biportal endoscopic discectomy. Both groups showed improvements in VAS, ODI, and EQ-5D scores following surgery compared to preoperative scores. However, there was no significant difference in these outcome measures between the two surgical techniques. Although there was a no significant difference in the occurrence of recurrent disc herniation confirmed by postoperative MRI, there was significant difference in the number of patients requiring additional surgery between the two groups.
Conclusions
For obese patients with lumbar disc herniation that did not respond to conservative treatment, this study found no significant differences in clinical or radiological outcomes between microscopic and biportal endoscopic surgery methods. However, it is worth noting that the biportal group had a lower incidence of reoperation compared to the microscopic group.

Objective
Proximal junctional fracture (PJFx) at the uppermost instrumented vertebra (UIV) or UIV+1 is the most common mechanism of PJF. There are few studies assessing the radiographic progression after PJFx development. Therefore, this study sought to identify the risk factors for radiographic progression of PJFx in surgical treatment for ASD.
Methods
In this retrospective study, among 317 patients aged > 60 years who underwent ≥5-level fusion from the sacrum, 76 with PJFx development were included. According to the change in proximal junctional angle (PJA), two groups were created: Group P (change ≥10°) and Group NP (change <10°). Patient, surgical, and radiographic variables were compared between the groups to demonstrate risk factors for PJFx progression using uni- and multivariate analysis. The receiver operating characteristic (ROC) curve was used to calculate cutoff values. Clinical outcomes, such as visual analog scale (VAS) scores for back and leg pain, the Oswestry Disability Index (ODI) score, and the Scoliosis Research Society (SRS)-22 score, and revision rate were compared between the two groups.
Results
The mean age at the index surgery was 71.1 years, and there were 67 women enrolled in the study (88.2%). There were 45 patients in Group P and 31 in Group NP. A mean increase of PJA was 15.6° (from 23.2° to 38.8°) in Group P and 3.7° (from 17.2° to 20.9°) in Group NP. The clinical outcomes were significantly better in Group NP than Group P, including back VAS score, ODI value, and the SRS-22 scores for all items. Revision rate was significantly greater in group P than in group NP (17.8% vs. 51.6%, p=0.001). Multivariate analysis revealed that overcorrection relative to the age-adjusted ideal pelvic incidence (PI)–lumbar lordosis (LL) target at the index surgery (odds ratio [OR]=4.484, p=0.030], PJA at the time of PJFx identification (OR=1.097, p=0.009), fracture at UIV versus UIV+1 (OR =3.410, p=0.027) were significant risk factors for PJFx progression. The cutoff value of PJA for PJFx progression was calculated as 21° using the ROC curve.
Conclusions
The risk factors for further progression of PJFx were overcorrection relative to age-adjusted PI–LL target at the index surgery, PJA > 21° at initial presentation, and fracture at the UIV level. Close monitoring is warranted for such patients not to miss the timely revision surgery.

After posterior cervical arthrodesis, many problems can arise, including adjacent segment degeneration and the related adjacent segment disease (ASD). As indicated by studies on the causes of ASD, posterior cervical arthrodesis can produce biomechanical and kinematic changes in adjacent unfused segments due to inappropriate forces. Several studies have been conducted to determine the appropriate lowest instrumented vertebra, specifically regarding whether to cross the cervicothoracic junction via extension of long-segment posterior cervical fusion. We searched for relevant articles in electronic databases including PubMed, the Cochrane Registry, Embase, and Ovid. Five meta-analyses were reviewed on this topic. Among these, Goyal et al. (2019), Rajjoub et al. (2022), and Chang et al. (2022) argued that ending instrumentation at the cervical level was associated with higher rates of ASD and reoperation. However, Truumees et al. (2022) and Coban et al. (2022) found no statistically significant differences between cases of instrumentation ending at the cervical and thoracic levels in the rates of ASD and requirement of revision surgery. Cervicothoracic junction breakage is a known possibility after cervical spine surgery because of the anatomical fragility of the junction. Terminating at the thoracic level reduces the stress on the cervicothoracic junction, thereby decreasing complications such as cervicothoracic junction breakage and lowering the frequency of reoperation. Based on the findings published to date, instrumentation across the cervicothoracic junction can be reasonably recommended in cases of multilevel posterior cervical fusion based on the lower reoperation and higher fusion rate.

Background
The Selective thoracic fusion (STF) may be associated with risk of postoperative coronal decompensation, lumbar decompensation and adding-on phenomenon, which can lead to persistence of the lumbar curve and consequently to deviation of the trunk. Therefore, the STF is the most debatable issue as the optimal surgical correction in adolescent idiopathic scoliosis with Lenke 1C curves.
Methods
A total of 30 patients with adolescent idiopathic scoliosis with Lenke 1C curves who underwent STF between 1996 and 2017 were included. Minimum follow-up duration was five years. We analyzed the incidence of coronal decompensation, lumbar decompensation, distal adding-on phenomenon and trunk shift in these patients for radiographic adverse event. Clinical outcome was assessed by using the Scoliosis Research Society (SRS)-22r scores.
Results
The mean age at the time of surgery was 13.8±2.9 years. The mean follow-up duration was 80.4±12.3 months. The Cobb’s angle for main thoracic curve improved by 59.6% (p<0.001), and also The Cobb’s angle for thoracolumbar/ lumbar curve improved by 40.5% comparing preoperative and postoperative values (p<0.001). There was significant improvement in the Cobb’s angle for main thoracic and Thoracolumbar/lumbar curve comparing preoperative and last follow-up values (p<0.001). At last follow-up, the coronal balance was 10.3 ± 9.1 that significant improved from the immediate postoperative value (p=0.033). The incidence of coronal decompensation, lumbar decompensation, adding-on and trunk shift in our cohort was 16.7%, 10.0%, 13.3% and 10.0% respectively. The average SRS score at last follow-up in patients with radiographic adverse events was 4.3±0.5. That of patients without adverse events was 4.4±0.6. All domains between patients with and without adverse events had no statistical significance difference.
Conclusions
Selective thoracic fusion in Lenke 1C curves have acceptable risk of coronal decompensation, lumbar decompensation, distal adding-on, trunk shift. However, no revision surgery was required in these patients after long term follow-up. Therefore, STF in Lenke 1C curves seems to be enough.

Background
It is well reported that the patient’s age plays an important role associated with proximal junctional failure (PJF) development. Various characteristics of adult spinal deformity (ASD) patients were different between younger and older age groups. We hypothesized that the radiographic risk factors for PJF would different according to younger and older age groups. This study aimed to evaluate different radiographic risk factor of PJF according to the two age groups undergoing thoracolumbar fusion for ASD.
Methods
ASD patients aged ≥ 60 years who underwent thoracolumbar fusion from low thoracic level (T9~T12) to sacrum were included. The minimum follow-up duration was two years. PJF was defined as proximal junctional angle (PJA) ≥ 20°, fixation failure, fracture, myelopathy, or necessity of revision surgery. Using various radiographic risk factors including age-adjusted ideal pelvic incidence (PI)-lumbar lordosis (LL), univariate and multivariate analyses were performed separately according to the two age groups : <70 years and ≥70 years.
Results
A total of 186 patients were enrolled (mean age=68.5 years old, 90.3% female). Mean follow-up duration was 67.4 months. PJF developed in 98 patients (32.0%). There were fracture in 53 patients, PJA ≥ 20° in 26, fixation failure in 12, and myelopathy in 6. PJF developed more frequently in patients older than 70 years than in younger than 70 years. In patients aged less than 70 years, preoperative LL, PI-LL and change in LL were significant risk factors in univariate analysis. Multivariate analysis showed only change in LL was significant for PJF development (Odds ratio [OR]=1.025, p=0.021). On the other hand, in patients older than 70 years, postoperative LL, postoperative PILL, overcorrection relative to conventional PI-LL target (within ±10°) as well as age-adjusted ideal PI-LL target were significant. On multivariate analysis, only overcorrection of PI-LL relative to age-adjusted ideal target was a single significant factor to cause PJF (OR=5.250, p=0.024).
Conclusions
In patients younger than 70 years, greater change in LL was associated with PJF development regardless of PI-related value. However, in older patients, overcorrection of PI-LL relative to the age-adjusted PI-LL target was important to cause PJF.

Background
When obese patients underwent lumbar discectomy using a microscope, a correlation was found between the operation time and an increase in estimated blood loss according to the increase in body mass index. However, except for minor complications, there was no difference in postoperative outcomes between obese and normal-weight patients. These are the results of microscopic lumbar discectomy in obese patients, but there are no studies on biportal endoscopic lumbar discectomy. The aim of this study was to compare the clinical and radiographic outcomes of microscopic and endoscopic discectomy in obese patients.
Methods
Clinical and radiological data were compared and analyzed in 23 obese patients with a body mass index of >30 kg/m² who underwent microscopic and biportal endoscopic lumbar discectomy. Clinical data on the visual analog scale (VAS), Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D) scores were measured, and radiological data were measured using magnetic resonance imaging (MRI).
Results
In total, 13 patients who underwent microscopic discectomy and 10 who underwent biportal endoscopic discectomy were enrolled in this study. The VAS, ODI, and EQ-5D scores in both groups improved after surgery compared with those before surgery, although there was no difference between the two groups. Although there was a difference in the incidence of recurrent disc herniation confirmed by MRI after surgery, there was no difference in the number of patients requiring surgery between the two groups.
Conclusions
There were no significant clinical or radiological differences in outcomes between microscopic and biportal endoscopic surgery methods.

Background
Percutaneous-short segment screw fixation (SSSF) without bone fusion has proven to be a safe and effective modality for thoracolumbar spine fractures (TLSFs). When fracture consolidation is confirmed, pedicle screws are no longer essential, but clear indications for screw removal following fracture consolidation have not been established.
Methods
In total, we enrolled 31 patients with TLSFs who underwent screw removal following treatment using percutaneous-SSSF without fusion. Plain radiographs, taken at different intervals, measured local kyphosis using Cobb’ angle (CA), vertebra body height (VBH), and the segmental motion angle (SMA). A visual analogue scale (VAS) and the Oswestry disability index (ODI) were applied pre-screw removal and at the last follow-up.
Results
The overall mean CA deteriorated by 1.58º (p<0.05) and the overall mean VBH decreased by 0.52 mm (p=0.001). SMA preservation was achieved in 18 patients (58.1%) and kyphotic recurrence occurred in 4 patients (12.9%). SMA preservation was statistically significant in patients who underwent screw removal within 12 months following the primary operation (p=0.002). Kyphotic recurrence occurred in patients with a CA ≥20º at injury (p<0.001) with a median interval of 16.5 months after screw removal. No patients reported worsening pain or an increased ODI score after screw removal.
Conclusion
Screw removal within 12 months can be recommended for restoration of SMA with improvement in clinical outcomes. Although, TLSFs with CA ≥20º at the time of injury can help to predict kyphotic recurrence after screw removal, the clinical outcomes are less relevant.

Purpose
Minimally invasive technique in spinal surgery have evolved including cortical bone trajectory (CBT) screw technique which is s new lumbar pedicle screw path, as an alternative fixation technique for lumbar spine. Theoretical advantage is that it provides enhanced screw torque and has biomechanical characteristics, also it minimizes approach-related damages. Midline lumbar fusion (MIDLF) has appeared with CBT screw technique. Many studies of CBT screw reported the effectiveness of MIDLF. We adopted this technique for lumbar degenerative spondylolisthesis and evaluated early radiological outcomes.
Materials and Methods
From May 2014 to March 2015, 17 patients (mean age 65.6±7.5 years; 4 males, 13 females) underwent MIDLF procedures for the treatment of single level lumbar spondylolisthesis. Average follow-up period was 8.8±2.7 months. Initial and last follow-up X-ray and computed tomography (CT) were evaluated for screw malposition, detection of peri-screw halo, loosening of the construct, or signs of spinal instability.
Results
The average bone mineral density (BMD) was -1.9±0.8. Eleven patients were fused at L4-5, 5 were at L3-4, and 1 was at L2-3. Five CBT screws were converted into pedicle screws due to intraoperative misposition of screws, so total 63 CBT screws were evaluated for peri-screw halo and malposition. There were no findings of screw pull-out or breakage in all screws. Four out of 63 (6.3%) screws were judged as peri-screw halo, and 20 (41.2%) screws were judged as malposition (1 medial; 2 superior; 17 lateral pedicle violation). But, there were no screw related nerve root injury. In all cases, interbody bony mass were identified. Four out of 17 (23.6%) patients were detected more than 2 degrees motions on flexion-extension lateral X-rays at final follow-up, and 1 out of these 4 patients was identified loss of reduction. There was no operation related complication.
Conclusion
There is no doubt that MIDLF with CBT screw is the minimally invasive method. Many numbers of screw malposition identified in our series were thought to be due to our earlier experience of trying free hands technique. We recommend the use of intraoperative fluoroscopy, which achieve accuracy. Although MIDLF with CBT has theoretical strengths, we must evaluate further long-term clinical follow-up and measure outcome.

Objective
The purpose of this study is to investigate the radiological risk factors and differences in spinopelvic parameters for radiologic degenerative changes in the sacroiliac joint after lumbar or lumbosacral fusion surgery.
Materials and Methods
From 2019 to 2020, 116 patients diagnosed with lumbar and sacral degenerative diseases who underwent lumbar or lumbar sacral fusion were included. The degenerative changes of the sacroiliac joint were measured by CT performed before and 6 months after surgery, and divided into two groups according to the presence or absence of radiographic degeneration. Evaluation factors for radiographic degeneration include sclerotic changes, erosion, osteophyte formation, intra-articular bone formation, joint space narrowing, intra-articular gas formation and subchondral cysts were evaluated. Spinopelvic radiologic parameters and surgery-related parameters including lumbar lordosis, sacral slope, pelvic incidence, global tilts, and T1PA between the two groups were analyzed using Student's t-tests and chi-square tests to determine the difference between continuous and non-continuous variables between groups. Logistic regression analysis was used for the analysis of risk factors for degeneration for SI joints after lumbar or lumbosacral fusion surgery.
Results
There was no statistically significant difference between the demographic data and surgery-related data between the group with and without sacroiliac joint degenerative changes. There was also no statistical difference in the rate of degenerative changes in the sacroiliac joint according to the presence or absence of S1 in the fusion segment. (degeneration group vs non-degeneration group; 45.5% vs 39.8%, p: 0.574) There were statistically significant differences between the two groups in lumbar lordosis (LL), pelvic angle of incidence (PI), and PI-LL. (LL; 27.2±12.0 vs. 39.8±11.3, PI; 51.3±12.0 vs. 57.2±12.6. and PI-LL; 24.1±17.0 vs 17.4±13.9, p: <0.001, 0.023, and 0.030) As risk factors for radiographic degenerative changes in the sacroiliac joint, lumbar lordosis (LL), pelvic incidence (PI), sacral inclination (SS), and sagittal vertical axis (SVA) were statistically significant factors. (lumbar lordosis Odd ratio: 0.851, 95% CI: 0.791-0.917, p-value <0.001)
Conclusions
Lumbar lordosis and pelvic incidence are related as risk factors for radiographic degenerative changes in the sacroiliac joint after surgery in patients with lumbar spinal fusion.

Background
Oblique and anterior lumbar interbody fusion have been widely performed in the lumbar spinal disease but we cannot get a direct decompression effect with these procedure. Objective: The purpose of this study is to report clinical and imaging outcomes of microscope assisted direct decompression combined with oblique lumbar interbody fusion (OLIF) or anterior lumbar interbody fusion (ALIF).
Methods
Twelve patients who received microscope assisted direct decompression during OLIF or ALIF for lumbar spinal stenosis were enrolled. The OLIF was performed for the lesion upper than the L4-5 or in the case of multisegmental disease. The ALIF was performed for the lesion at the L5-S1. After anterior-approaching surgery, percutaneous fixation of pedicle screw was performed and we did not perform an additional decompression posteriorly in all cases. For the clinical outcomes, we evaluated short form 36 (SF-36), Oswestry disability index (ODI) score and visual analog scale (VAS) pain score. For the imaging outcomes, we obtained postoperative lumbar magnetic resonance imaging (MRI).
Results
The OLIF was performed for 9 patients and the ALIF was performed for 3 patients. In the clinical outcomes, SF-36 was improved from 25.40 to 69.83 and ODI score was also improved from 69.83 to 16.50. VAS pain score of back was improved from 4.3 to 1.6 and VAS pain score of leg was improved from 7.5 to 2.2. In the imaging outcomes, all patients had severe stenosis before surgery. After surgery the severity of the stenosis was reduced to mild state in 9 cases and moderate state in 3 cases postoperatively.
Conclusions
We could obtain the good clinical outcomes and effective decompression through microscope assisted direct decompression during OLIF or ALIF.

Purpose
The current study aims to report the results of analyzed factors that ultimately undergo surgical treatment after selective nerve root block in patients with spinal structural pathology that cause lower back pain and radiating pain in the lower extremities. Material and methods: A retrospective study was performed on 537 patients diagnosed with spinal canal stenosis or disc herniation among patients who underwent selective nerve root block at our hospital for five years from May 2015 to December 2017. The patients were divided into Group A (patients with an only selective spinal nerve root, n=99) and Group B (patients with surgical treatment, n=20). We evaluated the primary demographic factors, including age, sex, onset, symptom duration, diabetes mellitus, hypertension, angina, osteoporosis. The clinical variables included in the analysis were the preoperative visual analog scale (VAS) pain score, the Korean version of the Oswestry Disability Index (K-ODI), and the Roland-Morris disability questionnaire (RMDQ).
Results
The average symptom duration was 22.6±1.2 weeks in group A, and 35.7±0.9 in group B. Of a total of 20 patients (16.8%), four males (20%) and 16 females (80%) were underwent surgical procedures because there was no improvement in symptoms. Group B had a significantly higher proportion of female patients and longer symptom duration than group A. And there were no statistically significant differences between groups in other variables.
Conclusions
Although the frequency of surgical treatment decreased after selective nerve root block, the longer symptom duration and the female gender might be related to the risk factors for surgical treatment.

Objective
This study aimed to compare the efficacy of unilateral biportal endoscopic decompression (UBE) and percutaneous endoscopic lumbar discectomy (PELD) in reducing muscle injury by measuring serum levels of creatine phosphokinase (CK) and lactate dehydrogenase (LDH).
Materials and Methods
Thirty patients with degenerative lumbar stenosis or a herniated lumbar disc underwent decompression surgery. Among them, 12 patients underwent UBE (experimental group, n=12) and 18 underwent PELD (control group, n=18). CK and LDH were determined at admission and 1, 3, and 5 days after surgery. Pain was measured with a visual analogue scale (VAS).
Results
The mean age was significantly higher in the UBE group than the PELD group (63.33±13.50 vs. 49.94±14.79, p<0.035). Mean CK levels were not significantly different at admission. However, at both 3 and 5 days after surgery, CK levels were higher in the UBE group (308.44±153.93 vs. 70.43±40.15, p=0.002; 157.11±91.41 vs. 47.62±23.13, p=0.007). The mean LDH level was higher in the PELD group at 1 day after surgery (152.55±34.69 vs. 199.87±53.78, p=0.027). The operation time was significantly shorter in the PELD group (90.67±39.59 vs. 49.43±14.11, p=0.003).
Conclusions
The UBE group had higher CK levels at 3 and 5 days after surgery. The PELD group had a higher LDH level at 1 day after surgery. Therefore, neither procedure is clearly superior in terms of muscle damage.

Background
S2-alar-iliac (S2AI) screws are one of the options for spinopelvic fixation to improve stability across the lumbosacral junction. The S2AI screws cross the cortical surfaces of the sacroiliac joint, which can increase the biomechanical strength of the instrumentation. Objective: To investigate the durability and failure types of S2AI screw by finite element model (FEM) analysis.
Methods
Through the FEM, complex material and geometrical properties of the biological system can be evaluated, and various physical variables, such as stress, and fracture, can be analyzed. We examined the biomechanical stress distribution at the set screw and screw head by using a FEM. Von Mises (V.M.) stress (MPa) is derived from 3-dimensional status of stress. The finite element software Abaqus^® version 6.5 (ABAQUS Inc., Johnston, RI, USA) was used to create a FEM.
Results
We quantified the peak V.M. stress applied to the set screw and screw head when rod to S2AI screw trajectory angle was 30º angled and perpendicular. In FEM analysis, at an angle of 30 degrees rather than perpendicular, the stress increased further around the area where the screw head and rod contacted and the displacement distribution of set screw also increased.
Conclusion
S2AI screw fixation has several drawbacks such as screw fracture and dislodgement of the set screw. This FEM analysis can support the result.

Vertebral compression fracture is one of the most common osteoporotic fractures along with hip fractures. In some patients, pain was improved through conservative treatment including pharmaceuticals, bracing and physiotherapy. But it has been reported that conservative therapy is insufficient in many patients with vertebral compression fracture. Accordingly, interest in vertebroplasty has increased and many studies have been reported that vertebroplasty have therapeutic effects in acute vertebral compression fracture. On the other hand, some studies have been reported that the effect of vertebroplasty was not significant. So whether vertebroplasty is useful or not is still controversial. Therefore, in this review article, we will review open-label randomized controlled trials and blinded randomized controlled trials that provide high-level evidence and provide an opinion on which patients it is appropriate to perform vertebroplasty.

Spinal subdural hematoma (SDH) is a rare complication after spinal surgery. Only a few cases are reported on spinal SDH following open lumbar spinal decompression or fusion surgery. Moreover, there has been no case report on spinal SDH following percutaneous transforaminal endoscopic lumbar discectomy. We report a case of spinal SDH following endoscopic discectomy, review the literature of this complication and discuss the etiology to it and methods to prevent it. A 63-year-old woman presented with severe radiating pain. Pain was not improved with conservative management. Lumbar magnetic resonance imaging (MRI) was checked and revealed right L3-4 ruptured disc with severe L4 root compression. Percutaneous transforaminal endoscopic decompression was performed and the pain subsided promptly after the endoscopic procedure. On 7th post-operative day, pain on Rt. buttock, anterior thigh was deteriorated severely, more than in pre-operatively. Deteriorated pain was not controlled by oral medications and epidural block. Repeat MRI showed no definite recurrence of disc herniation at decompressed level but spinal SDH, severely compressing cauda equina was seen on T12-sacral area. Spinal SDH is a rare complication following spine surgery, including percutaneous endoscopic surgery. A spine surgeon should be aware of the possibility of spinal subdural hematoma, having severe sequel.

Background
Proximal junctional kyphosis (PJK) following long instrumented fusion is a well-recognized complication that does not negatively affect the clinical outcomes. However, there were few studies with regard to the long-term consequences of PJK. Objective: To investigate the long-term clinical and radiographic consequences of proximal junctional kyphosis (PJK) following the long instrumented fusion for elderly patients with sagittal imbalance.
Methods
Patients older than 60 years who underwent ≥4 fusion including the sacrum for sagittal imbalance were followed up longer than five years. PJK was defined as proximal junctional angle (PJA) >10° without any bony compromise or myelopathy. The radiographic and clinical outcomes were compared between PJK and non-PJK groups. Clinical outcome measures included visual analog scale (VAS) for back and leg, Oswestry disability index (ODI), and Scoliosis Research Society (SRS)-22 scores.
Results
A mean age was 69.2 years. An average follow-up duration was 92.4 months. There were 30 patients in PJK group and 43 in non-PJK group. At the final follow-up, pelvic incidence-lumbar lordosis mismatch, pelvic tilt, and sacral vertical axis were not different between the two groups. In PJK group, PJA significantly increased from 6.5° postoperatively to 21.2° at the final follow-up. At the final follow-up, clinical outcomes were worse in PJK group than in non-PJK group with regard to VAS for back, ODI, and SRS-22 scores except satisfaction domain. Three (10%) of 30 patients underwent a revision surgery for PJK progression.
Conclusions
PJK progressed with time and negatively affect the clinical outcomes in a long-term follow-up after ASD surgery.

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.

Objectives
to report a surgical site infection from Aspergillus after a lumbar discectomy. Aspergillus is ubiquitous fungus. People with normal immunity are usually not infected by it, however, surgical site infection from it often developed even in normal population.
Materials and Methods
The diagnostic and therapeutic experience of 55-year-old male patient who underwent L45 discectomy who had surgical site infection from Aspergillus was reviewed.
Results
He had 4 times surgical treatment and empirical antibiotic therapy due to progressive extension of infection without microbiologic confirmation. Aspergillus flavus was identified at 5th operation and he was cured by adding an anti-fungal agent.
Conclusions
An Aspergillus infection after an operation can be developed even in normal immunity population. If a surgical site infection patient without fever and draining sinus does not improve by conventional treatment, Aspergillus infection should be considered.

Introduction
We describe the complications that can occur after percutaneous vertebroplasty using bone cement for osteoporosis vertebral compression fracture. Main subject: The most common complication of percutaneous vertebroplasty is the leakage of bone cement. Leakage of bone cement has been reported variously and could leak into the spinal or neural foramen, adjacent intervertebral disc and soft tissues around the spine, and venous systems. The most serious complications are neurologic symptoms due to spinal cord and nerve root compression and complications associated with death due to heart and pulmonary embolism. In addition, recompression fracture or adjacent vertebral compression fracture might occur and various treatment methods have been proposed.
Conclusion
The complications that can occur after percutaneous vertebroplasty have been reported variously, including neurologic deficits due to the leakage of bone cement and lung and heart embolism. In addition, there is a possibility of recompression fracture or adjacent compression fracture. Therefore, you should be careful about percutaneous vertebroplasty. Finally, patients with many risk factors regarding complications of vertebroplasty would need close observation and follow-up.

Cervical ossification of posterior longitudinal ligament (OPLL) can cause cord compression which can lead to myelopathy. Operative management including anterior fusion or laminoplasty is needed in these cases. Understanding the progression course of OPLL, risk factors of progression, and risk factors of myelopathy caused by OPLL is essential to determine the necessity, timing and method of operation. Therefore, we will review the previous study results regarding characteristics and progression course of OPLL. Furthermore, the results of study about risk factors and progression course of OPLL undergoing conservative management will be discussed.

When conservative treatment fails in the treatment of osteoporotic vertebral compression fractures, a minimally invasive procedure, such as percutaneous balloon kyphoplasty or vertebroplasty is performed. Among these, balloon kyphoplasty is known as an advantageous method for lower risk of cement leakage and greater correction effect of kyphosis and better sagittal balance correction. However, there are reports of various complications during and after procedure, and sometimes result in serious consequences. This paper reviews with previous literatures about the complications related to balloon kyphoplasty.

Objectives
The primary surgical goals when treating a spinal metastasis are usually pain relief and preservation of ambulatory function. Minimally invasive techniques have become popular, being associated with less morbidity and mortality than conventional open surgeries.
Materials and Methods
Between April 2012 and September 2016, 15 consecutive patients underwent percutaneous pedicle screw fixation (PPSF) to treat spinal metastases. We retrospectively analyzed prospectively collected data, including visual analog scale (VAS) pain scores, Frankel scale scores, and complications.
Results
Fifteen patients (8 males, 7 females; mean age 61 years) underwent surgery under general anesthesia. PPSF was performed on all patients, and two with poor bone quality underwent cement augmentation of the manipulated vertebra(e) just prior to pedicle screw insertion. Seven patients underwent fixation plus distraction (indirect decompression via ligamentotaxis) and two laminectomies (direct decompression) of the spinal cord. Two patients developed screw pullout requiring revision surgery. One patient died 7 days after surgery from liver cirrhosis and sepsis. All patients reported that pain was reduced after surgery. After surgery, 12 patients regained ambulatory capacity. Nine patients died during follow-up; the mean overall survival time was 14.1 months.
Conclusions
PPSF is a safe and minimally invasive palliative surgery option for patients with spinal metastases.

Purpose
To evaluate and analyze the clinical results of lumbar microdiscectomy using minimally invasive tubular retractor between recurrence and non-recurrence group, and to assess the merits of minimally invasive spinal surgery. Overview of Literature: No large registry study has so far investigated the clinical results of lumbar microdiscectomy using minimally invasive tubular retractor.
Methods
From July 2003 to April 2011 we retrospectively studied a consecutive series of 156 patients who underwent lumbar microdiscectomy using minimally invasive tubular retractor. The following data were collected: clinical outcomes, operative time, intraoperative blood loss, recurrence, and complications. The clinical outcomes were measured using a visual analog scale (VAS) and assessed by the modified MacNab criteria.
Results
Minimally invasive tubular microdiscectomy was performed in 156 patients. The clinical outcomes assessed by MacNab criteria were excellent in 63 patients (40%), good in 71 patients (45%). VAS scores of low-back pain decreased from a mean of 6.7 prior to surgery to 2.5 after surgery, and that of leg pain decreased from 7.2 to 2.1. The average operative time was 68 minutes (range, 25 to 180 minutes). The average blood loss was 42 mL (range, 0 to 500 mL). None of the patients needed blood replacement. One patient had wound infection problem but there was no dural tear case. Twenty-two patients had recurrence. Average time to recurrence was about 42 months. Seventeen cases recurred at the same level and five cases recurred at the adjacent level. Eleven cases in 22 patients with recurrence were contained disc type and the others were non-contained disc type. Eighteen cases in 22 patients with recurrence were paracentral disc herniation type and the others were far lateral type. Average body mass index (BMI) of recurrence cases was 24.7 (range, 17.5 to 31.3) and that of non-recurrence cases was 24.5 (range, 16.3 to 39.2).
Conclusions
Lumbar microdiscectomy using tubular retractor can offer a useful modality for the treatment of lumbar herniated disc with the merits of minimally invasive spinal surgery. Further randomized, prospective investigations are needed to fully evaluate the impact of this technique.

Interspinous process devices for spinal surgery are designed to keep the spine in a flexed position, to achieve indirect decompression of the mobile segment. Such devices have been fabricated using numerous materials and designs. In this study, the fundamental knowledge required for choosing an appropriate interspinous process device for spinal surgery was reviewed.