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.

Background
Context: There are few reports of changes in global sagittal alignment and corresponding factors like hand grip strength (HGS) and muscle performance tests to detect changes in global sagittal alignment after surgery for lumbar spinal stenosis (LSS). Purpose: The purpose of the study was to determine whether HGS can be a useful predictive marker of global sagittal alignment changes after decompression with fusion surgery for LSS. Study Design: This is a retrospective observational study. Patient Sample: Patients who underwent spine surgery for LSS were included in the present study. Outcome Measures: Radiological spinopelvic parameters including sagittal vertical axis (SVA), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), global tilt (GT), and T1 pelvic angle (T1PA) were assessed. Clinical outcomes parameters like Oswestry Disability Index (ODI), Euro-QOL (EQ-5D), visual analog scale (VAS) scores for back or leg pain were assessed. To assess muscle performance, three functional mobility tests (6-meter walk test, timed up and go test, sit-to-stand test) and HGS were checked.
Materials and Methods
A total 91 consecutive patients who underwent spine fusion surgery for LSS were included. 1 year after posterior decompression and fusion surgery, the patients were further classified into four groups according to preoperative and postoperative SVA. We analyzed radiological parameters like SVA, LL, PT, PI, GT, and T1PA. The ODI, the EQ-5D and VAS scores for back or leg pain were recorded as clinical outcomes assessment. To assess muscle performance, SMT, TUGT, STS, and HGS were checked.
Results
HGS was significantly correlated with age, postoperative SVA, ODI, EQ-5D and muscle performance test. HGS was related with change of preoperative sagittal alignment 1yr after surgery. Using a receiver operating characteristic (ROC) curve to determine the cutoff values of HGS as predictors of postoperative balanced sagittal alignment according to SVA, cutoff value of HGS demonstrated 19.5 kg with a sensitivity of 82.1% and specificity of 66.7%.
Conclusion
Patients with non-balanced sagittal alignment in LSS demonstrated decreased muscle function and muscle strength. If the muscle strength was weak in the group in which the sagittal balance was maintained preoperatively, it could be converted to non-balanced sagittal alignment. Thus, preoperative HGS may be a good predictor of postoperative SVA change.

Background
Owing to its new introduction, there are few documents on pit-falls of biportal endoscopic spine surgery (BESS) clinically. The authors reported etiologies in need of early exploration after BESS for lumbar degenerative diseases and strategies to overcome them.
Methods
BESS were performed for lumbar spine diseases (LSDs) by two spine surgeons from December 2013 to March 2016. Postoperative MRI was checked for all cases and following-up MRIs in the case in need of revision surgery within six months after the first surgery due to pain intolerable, sustained or recurred. The complicated cases were reviewed and classified as radiographic and operative findings to reveal the main reasons for early explorations.
Results
The 562 cases (M:295, F:267, Age 58.5±14.1 yrs, 20~88 yrs) included lumbar disc herniation (LDH) (255 cases), extraforaminal disc herniation (22 cases), spinal stenosis (218 cases), degenerative spondylolisthesis (27 cases), revision surgery after recurred disc herniation or restenosis after open surgery (24 cases), juxtafacet cyst (11 cases), adjacent segment stenosis with fusion surgery (3 cases), and spondylolytic spondylolisthesis (2 cases). Early explorations were needed in 43 cases (7.7%) at 26.1±31.5 days after the initial operations. Causative etiologies were listed as recurred LDH (12 cases, 27.9%), remnant stenosis (7 cases, 16.3%), remained ruptured disc fragment (6 cases, 14.0%), root edema (5 cases, 11.6%), synovitis (4 cases, 9.3%), hematoma (3 cases, 7.0%), dura tear (2 cases, 4.7%), recurred stenosis (2 cases. 4.7%), wrong level (1 case, 2.3%) and postoperative fungal infection (1 case, 2.3%). Thirty-one cases (72.1%) were revised within 4 weeks and most conditions (40 cases, 93.0%) were improved after early exploration using BESS. Two cases of dura tear were conversed to open repair. One case of fungal infection was suspected to related with the patient’s medical illness including long-term steroid use for chronic lung disease with pulmonary fibrosis and Diabetes mellitus.
Conclusions
Preoperative planning should be prepared carefully to decrease early exploration. It was helpful to comparing MRIs immediately postoperative and early following-up to find the reasons. Don’t hesitate to explore the operated site again using BESS, because most etiologies are supposed to be controlled by early exploration without need of converting to open surgery except in the case of dura tear in need of dural repair.

Purpose
of study: The purpose of this study is to understand the biomechanics of interspinous devices in lumbar spinal surgery and to review the effectiveness of the devices for lumbar spinal stenosis through recent related articles.
Materials and Methods
Medical databases were searched for the key words of interspinous device and lumbar spinal stenosis using PubMed from 2010 to the present.
Results
Several studies have shown sustained symptomatic improvements after interspinous device insertion. However, most of the prospective, randomized, double-blinded studies have shown that it is not superior to conventional laminectomy from a statistical perspective. Furthermore, interspinous device insertion has been shown to have a higher reoperation rate and to be less cost effective.
Conclusions
A large prospective cohort study with a longer follow-up period comparing decompressive surgery alone versus interspinous device insertion for the treatment of lumbar spinal stenosis is needed to conclusively determine whether the interspinous device is beneficial.

Lumbar spinal stenosis is one of the degenerative diseases which have increasingly grown, as the nation is transitioning to an aging society. Even though medication is readily available as treatment for lumbar spinal stenosis, surgical treatments can be considered if symptoms are severe. The most basic operation, laminectomy and decompression, alone, can bring about improvements of symptoms by alleviating the pressure of the nerve root, however if instability is evident on the radiograph or during surgery, spinal fusion will be performed, and will yield favorable results. On the contrary, it is also common knowledge that spinal fusion can give rise to a variety of complications afterwards. New surgical procedures and apparatuses have been developed and used in clinical practices in order to overcome these complications. One of these new concepts is posterior dynamic stabilization. The purpose of posterior dynamic stabilization is to enable the spine to adjust so that, by limiting the movement to the direction which causes the pain, patients can feel at ease. Until recently, interspinous devices have been developed and applied in clinical practices in order to improve the symptoms of patients. The device is inserted after decompression of the nerve root in between the spinous processes of the lumbar part, where the symptom is present. By doing so, it not only limits the extension (without impacting flexion, axial rotation, and lateral bending) but also, alleviates the load on the facet joint by playing a role as a shock absorber. However, it is also true that the practice of this surgery has been limited due to the reports showing that; halo formed between the contact surface of the bone and the metal device might be the cause of pain; and according to a follow-up survey, fractures of the spinous process, breakaway of apparatus and post-operative complication such as kyphosis may be present. This paper will investigate the usefulness of these devices again by looking at the fundamental biomechanical effect of interspinous devices and analyzing the thesis which has been previously published.