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
To evaluate whether the contralateral radiating pain improved after unilateral decompression and minimally invasive transforaminal lumbar interbody fusion (TLIF) in the patients with bilateral radiating pain due to degenerative lumbar disease.
Materials and Methods
Patients with the degenerative lumbar disease who underwent unilateral minimally invasive TLIF and were followed for more than 1 year were included. Clinically, low back pain and radiating pain on the dominant symptom side and the contralateral side were evaluated by the visual analogue score (VAS), and the Oswestry disability index (ODI) score was also evaluated.
Results
ODI and VAS of low back pain and radiating pain were effectively reduced in a total of 57 cases. Thirty cases having bilateral radiating pain, among these patients, unilateral decompression was performed in 15 cases and bilateral decompression thru unilateral approach in 15 patients. In unilateral decompression group, radiating pain on the dominant symptom side, and radiating pain on the contralateral side were also improved at the final followup. In 15 cases who underwent bilateral decompression, radiating pain on the dominant symptom side and the contralateral side were improved at the final follow-up. There was no significant difference between the two groups in terms of preoperative ODI, VAS of low back and radiating pain.
Conclusions
Minimally invasive TLIF via unilateral approach with or without contralateral decompression showed good clinical results in patients having unilateral or bilateral radiating pain. Minimally invasive TLIF could be an useful option even if there is bilateral radiating pain in degenerative lumbar disease.

Purpose
This study examined the utility of PainVision (Nipro, Osaka, Japan) calculating the degree of lower back pain, as compared with conventional pain assessment (Numeric Rating Scale [NRS], McGill Pain Questionnaire [MPQ]).
Materials and Methods
A retrospective study was conducted from March 2021 to July 2021 on 40 patients with low back pain. NRS score, MPQ score and the degree of pain calculated by PainVision were measured before and after facet joint block in each patient. An electrode was patched on opposite side of lower back surface at which the patients complain of pain and the degree of pain was automatically calculated (degree of pain=100×[current producing pain comparable with low back pain–current at perception threshold/current at perception threshold]). Correlations between NRS and MPQ scores and the degree of pain were determined using Spearman’s rank correlation test.
Results
There was a strong correlation between the NRS and MPQ scores at each time point (before: rs=0.67, p<0.0001, after: rs=0.78, p<0.0001). The degree of pain before facet joint block also showed a moderate correlation with NRS and MPQ scores at each time point (NRS: rs=0.60, p<0.0001, MPQ: rs=0.343, p<0.03). The change in the degree of pain after facet joint block showed a moderate correlation with changes in the NRS and MPQ scores (NRS: rs=0.509, p<0.0001, MPQ: rs=0.581, p<0.0001).
Conclusions
The Pain vision can evaluate lower back pain well and quantify it in the form of pain degree, which is helpful for objective quantitative analysis of lower back pain.

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.

Objective
To evaluate the efficacy and safety of anorganic bone matrix (ABM)/P-15 compared with local autograft bone in posterior lumbar interbody fusion (PLIF) with pedicle screws for degenerative lumbar diseases.
Methods
This is a retrospective analysis of consecutive series of 138 patients undergoing 1 or 2 levels PLIF from 2015 to 2020 in our single institute. Local autograft bone or ABM/P-15 (i-factor, Cerapedics Inc., Westminster, Colorado USA) were used for interbody fusion. The successful fusion was defined as the segmental cobb angle of less than 5 degrees of in flexion/extension X-rays and continuity of the trabecular bony bridging in computed tomography (CT) images.
Results
Among a total of 138 patients, total levels of fusion were 202, of which 74 were in 1 level fusion and 128 were in 2 level fusion. And 93 used ABM/P-15 and 109 used local autograft bone. The evaluation time of fusion status was 1 year after surgery. Successful fusion based on X-ray images was achieved 84.1% (90/107) for local autograft bone and 91.3% (84/92) for ABM/P-15 (p=0.127). Based on CT images, 86.9% (93/107) of autograft group and 95.6%(87/91) of AMP/P-15 group showed successful fusion respectively (p=0.034). Occurrence rate of autolysis was 14% (15/107) for local autograft bone and 17.6% (16/91) for ABM/P-15. Subsidence rates were 11.2% (12/107) for local autograft bone and 9.99% (9/91) for ABM/P-15. Hollow formation around pedicle screw was noted in 9.3% (10/107) for local autograft bone and 2.2% (2/91) for ABM/P-15.
Conclusions
The use of AMP/P-15 for lumbar interbody fusion surgery can be a good substitute for local autograft bone in terms of better fusion rate and similar complication rate on radiologically.

In modern society, chronic low back pain is a common disease and is the most common cause of limiting social and economic activities in the population over the age of 45. Unlike general chronic low back pain patients, there may be cases of complaining of non-specific symptoms. However, it is difficult to diagnose or treat neuropathic chronic low back pain patients because they have a more complex pathophysiology than simple low back pain. Neuropathic chronic low back pain is caused by abnormal pain inducing mechanisms due to damage and dysfunction of the nervous system from the peripheral to the brain. Symptoms can occur anywhere in the vertebral or paravertebral structures where nociceptors are distributed. It is difficult to diagnose neuropathic back pain. Early and appropriate treatment can prevent the nervous system from being improperly adapted to become chronic pain syndrome, so it is very important as a clinician to access and diagnose neuropathic pain as easily as possible and apply general treatment early. Therefore, in this review article, based on literatures and research results on chronic low back pain with neuropathic component, we understand diseases and suggest directions for clinical applications.