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.

Objectives
We report the new minimally invasive technique and its clinical results of oblique lumbar interbody fusion (OLIF) combined with central decompression using biportal endoscopic spinal surgery (BESS). Summary of Literature Review: The OLIF procedure is one of the minimally invasive spine surgeries and is being frequently attempted recently to treat lumbar degenerative disease. It has been reported that it effectively decompresses foraminal stenotic lesions indirectly by inserting a large cage anteriorly, which reduces spondylolisthesis and widens the disc space. However, OLIF has limited effect for severe central canal stenosis, since it cannot achieve direct decompression. Therefore, authors report a new minimally invasive technique of OLIF combined with direct central decompression using BESS for severe central stenosis along with its clinical results as a pilot study.
Materials and Methods
For patients who were candidate for fusion surgery due to spondylolisthesis (more than one segment) or foraminal stenosis, authors performed OLIF and central decompression using BESS simultaneously, when the patients had concomitant severe central canal stenosis. From June to December, 2017, 8 patients (16 levels) were enrolled, the operative time, blood loss, complications and clinical results have been evaluated. The clinical results were analyzed by Visual analog scale (VAS) scores, Oswestry disability index (ODI) and Roland Morris Disability Questionnaire (RMDQ) of preoperative, 1month, 3month postoperative and final follow-up.
Results
Mean operative time and blood loss were 238.4 minutes and 173.3ml, respectively. In all cases, there were no operative complications, and mean follow-up period was 7.1 months. The mean back VAS, lower extremity VAS, ODI, and RMDQ at the final follow-up were improved from 5.4±2.4 to 2.0±0.9, 7.0±1.1 to 1.6±1.7, 64.2±11.8 to 44.2±10.6, and from 17.5±4.2 to 12.9±4.0.
Conclusion
A new combination technique of OLIF and BESS for direct decompression can be regarded as effective alternative procedure to treat the foraminal and central stenotic lesions of lumbar degenerative disease.