Swd2/Cps35 determines H3K4 tri-methylation via interactions with Set1 and Rad6.

BACKGROUND: Histone H3K4 tri-methylation (H3K4me3) catalyzed by Set1/COMPASS, is a prominent epigenetic mark found in promoter-proximal regions of actively transcribed genes. H3K4me3 relies on prior monoubiquitination at the histone H2B (H2Bub) by Rad6 and Bre1. Swd2/Cps35, a Set1/COMPASS component, has been proposed as a key player in facilitating H2Bub-dependent H3K4me3. However, a more comprehensive investigation regarding the relationship among Rad6, Swd2, and Set1 is required to further understand the mechanisms and functions of the H3K4 methylation. RESULTS: We investigated the genome-wide occupancy patterns of Rad6, Swd2, and Set1 under various genetic conditions, aiming to clarify the roles of Set1 and Rad6 for occupancy of Swd2. Swd2 peaks appear on both the 5' region and 3' region of genes, which are overlapped with its tightly bound two complexes, Set1 and cleavage and polyadenylation factor (CPF), respectively. In the absence of Rad6/H2Bub, Set1 predominantly localized to the 5' region of genes, while Swd2 lost all the chromatin binding. However, in the absence of Set1, Swd2 occupancy near the 5' region was impaired and rather increased in the 3' region. CONCLUSIONS: This study highlights that the catalytic activity of Rad6 is essential for all the ways of Swd2's binding to the transcribed genes and Set1 redistributes the Swd2 to the 5' region for accomplishments of H3K4me3 in the genome-wide level.

A Comparison of 2 Cage Sizes in Biportal Endoscopic Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective study. OBJECTIVE: This study compared the fusion and subsidence rate and clinical outcomes when using different-sized static PEEK cages in BE-TLIF. SUMMARY OF BACKGROUND DATA: Biportal endoscopic techniques for transforaminal lumbar interbody fusion (BE-TLIF) have been shown to have similar clinical and fusion outcomes with faster clinical recovery in comparison to tubular surgery. Subsidence of the interbody, however, could be a complication. METHODS: Patients who underwent 1 or 2 level BE-TLIF for degenerative and isthmic spondylolisthesis between January 2019 and January 2022 were included. A 32×10 mm cage (group A) and a 40×15 mm cage (group B) were compared. The visual analog scale (VAS) for back and leg symptoms, and Oswestry disability index (ODI) were collected. Plain radiographs and computed tomography assessed fusion and subsidence at a minimum of 12 months. RESULTS: Of the 69 enrolled patients, 39 group A patients (51 levels) and 30 group B patients (32 levels) were compared. The operation time per level was 123 ± 15.8 and 138 ± 10.5 minutes per fusion level in groups A and B, respectively (P < 0.05). ODI improved from 64.8 ± 6.2 to 15.7 ± 7.1 in group A and from 65.3 ± 5.6 to 15.1 ± 6.3 in group B at the final follow-up (P < 0.05). VAS leg and back score improvement between the groups did not differ; however, the 3-month postoperative VAS back improvement was significantly higher in group B. The final fusion rate at the final follow-up did not significantly differ; however, the fusion ratio at 1 year was higher in group B (P < 0.05). Subsidence occurred in 5 cases (9.8%) in group A and none in group B (P < 0.05). CONCLUSION: BE-TLIF using a larger cage can be performed safely with similar patient-reported outcome measures with a faster fusion rate with less subsidence risk. LEVEL OF STUDY: III.

Technical Feasibility and Early Clinical Outcome of Biportal Endoscopic Transforaminal Lumbar Interbody Fusion Using Larger Cage.

BACKGROUND: Transforaminal lumbar interbody fusion with biportal endoscopic guidance (BE-TLIF) has been previously reported with promising clinical results. However, complications such as delayed union or subsidence occurred as with open surgery. We assumed using larger cages would result in less occurrence of such complications. We aimed to analyze the clinical outcome and technical feasibility of BE-TLIF using larger cages, initially designed for oblique lumbar interbody fusion. METHODS: We enrolled cases that underwent single-level BE-TLIF between January 2021 and January 2022. Polyetheretherketone cages that were larger than the conventional size were used. Diagnoses were degenerative spondylolisthesis or isthmic spondylolisthesis. Visual analog scale scores of the back and leg and Oswestry Disability Index were collected perioperatively. Modified Macnab criteria were used to evaluate the patients at the final follow-up. Radiologic outcome of interbody fusion rate and perioperative complications were analyzed. RESULTS: A total of 35 cases were included in this study. The mean age was 67.5 ± 8.4 and consisted of 13 male patients, and the mean follow-up duration was 18.3 ± 3.7 months. The majority (32/35, 91.3%) of the index level was located within the lower lumbar region, L4-S1. Oswestry Disability Index scores improved from 65.4 ± 5.4 preoperatively to 15.4 ± 6.1 at the final follow-up (P < 0.001). Visual analog scale scores of the leg decreased from 7.9 ± 1.5 to 1.7 ± 1.5 at the final follow-up (P < 0.001). Per the modified Macnab criteria on the final follow-up, 94% of the patients reported good/excellent. Most (94.2%) of the patients showed fusion grade I and II at the 1-year follow-up. No patient showed subsidence or other postoperative complication. CONCLUSIONS: BE-TLIF using a larger cage was safely performed without risk of subsidence during the 1-year follow-up. A cage with a larger footprint may be advantageous in BE-TLIF in the aspect of interbody fusion and subsidence.

Regulation of glucose and glutamine metabolism to overcome cisplatin resistance in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is a bile duct cancer and a rare malignant tumor with a poor prognosis owing to the lack of an early diagnosis and resistance to conventional chemotherapy. A combination of gemcitabine and cisplatin is the typically attempted first-line treatment approach. However, the underlying mechanism of resistance to chemotherapy is poorly understood. We addressed this by studying dynamics in the human ICC SCK cell line. Here, we report that the regulation of glucose and glutamine metabolism was a key factor in overcoming cisplatin resistance in SCK cells. RNA sequencing analysis revealed a high enrichment cell cycle-related gene set score in cisplatin-resistant SCK (SCK-R) cells compared to parental SCK (SCK WT) cells. Cell cycle progression correlates with increased nutrient requirement and cancer proliferation or metastasis. Commonly, cancer cells are dependent upon glucose and glutamine availability for survival and proliferation. Indeed, we observed the increased expression of GLUT (glucose transporter), ASCT2 (glutamine transporter), and cancer progression markers in SCK-R cells. Thus, we inhibited enhanced metabolic reprogramming in SCK-R cells through nutrient starvation. SCK-R cells were sensitized to cisplatin, especially under glucose starvation. Glutaminase-1 (GLS1), which is a mitochondrial enzyme involved in tumorigenesis and progression in cancer cells, was upregulated in SCK-R cells. Targeting GLS1 with the GLS1 inhibitor CB-839 (telaglenastat) effectively reduced the expression of cancer progression markers. Taken together, our study results suggest that a combination of GLUT inhibition, which mimics glucose starvation, and GLS1 inhibition could be a therapeutic strategy to increase the chemosensitivity of ICC. [BMB Reports 2023; 56(11): 600-605].

Increased Complement-Associated Inflammation in Cytomegalovirus-Positive Hypertensive Anterior Uveitis Patients Based on the Aqueous Humor Proteomics Analysis.

Herpetic anterior uveitis-associated ocular inflammation is commonly manifested with ocular hypertension and glaucoma. Relative to other viruses, cytomegalovirus (CMV) positive hypertensive anterior uveitis is associated with high recurrences of uveitis, as well as with uncontrolled intraocular pressure (IOP) and a subsequent higher requirement for future glaucoma surgery. To gain novel insights into the pathogenesis of ocular hypertension in these patients, we investigated the proteome changes of the aqueous humor (AH) derived from the CMV hypertensive anterior uveitis (CMV-HAU; n = 10) patients and non-glaucoma (cataract; n = 10) patients using liquid chromatography with tandem mass spectrometry. Among a total of 562 proteins identified, fifty and fifteen proteins were significantly elevated and decreased, respectively, in the AH of CMV-HAU patients compared to the control subjects by ≥2 fold. Gene ontology (GO) enrichment and network analyses of elevated proteins revealed that the enrichment of protein was involved in the complement activation, the humoral immune response mediated by the circulating immunoglobulins, proteolysis, and platelet degranulation. In the AH of CMV-HAU, GDF (growth/differentiation factor)-15, the inflammatory marker belonging to the TGF-ß superfamily proteins, was significantly increased, while vasorin, an anti-TGF-ß protein, levels were decreased. The trabecular meshwork cells infected with CMV exhibited a significantly increased expression of inflammatory markers. Collectively, these data indicate increased complement factor associated inflammation and humoral immunity in CMV-HAU associated ocular hypertension.

Comparison of Minimal Invasive Versus Biportal Endoscopic Transforaminal Lumbar Interbody Fusion for Single-level Lumbar Disease.

STUDY DESIGN: Retrospective study. OBJECTIVE: The authors aimed to compare the clinical outcomes of biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) with those of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) using a microscope. SUMMARY OF BACKGROUND DATA: Lumbar spinal fusion has been widely performed for various lumbar spinal pathologies. Minimally invasive transforaminal interbody fusion using a tubular retractor under a microscope is a method of achieving fusion while reducing soft tissue injury. Recently, several studies have reported minimally invasive techniques for lumbar discectomy, decompression, and interbody fusion using biportal endoscopic spinal surgery. MATERIALS AND METHODS: This retrospective study included 87 patients who underwent single-level TLIF for degenerative or isthmic spondylolisthesis between 2015 and 2018. Thirty-two and 55 patients underwent BE-TLIF (group A) and MI-TLIF (group B), respectively. Visual Analogue Scale scores of the back and leg and Oswestry Disability Index were collected perioperatively.Further, data regarding perioperative complications, including length of hospital stay, time to ambulation, and fusion rate, were collected. RESULTS: The Visual Analogue Scale score at 2 weeks and 2 months postoperatively was significantly lower in group A (P=0.001). All other clinical scores showed improvement with no significant difference between the 2 groups (P>0.05). The difference in the fusion rates between group A (93.7%) and group B (92.7%) were not significant (P=0.43). CONCLUSIONS: Because BE-TLIF yieldeds lesser early postoperative back pain than did MI-TLIF, it may allow early ambulation and a shorter hospitalization period. BE-TLIF may be a viable alternative to MI-TLIF in patients with degenerative or isthmic spondylolisthesis with superior clinical results in the early postoperative period.

Learning Curve and Clinical Outcome of Biportal Endoscopic-Assisted Lumbar Interbody Fusion.

Interbody fusion is a common surgical technique for diseases of the lumbar spine. Biportal endoscopic-assisted lumbar interbody fusion (BE-LIF) is a novel minimally invasive technique that has a long learning curve, which can be a barrier for surgeons. Therefore, we analyzed the learning curve in terms of operative time and evaluated the outcomes of BE-LIF. A retrospective study of fifty-seven consecutive patients who underwent BE-LIF for degenerative lumbar disease by a single surgeon from January 2017 to December 2018 was performed. Fifty patients underwent a single-level procedure, and 7 underwent surgery at two levels. The mean follow-up period was 24 months (range, 14-38). Total operative time, postoperative drainage volume, time to ambulation, and complications were analyzed. Clinical outcome was measured using the Oswestry Disability Index (ODI), Visual Analog Scale (VAS) score for back and leg pain, and modified Macnab criteria. The learning curve was evaluated by a nonparametric regression locally weighted scatterplot smoothing curve. Cases before the stable point on the curve were designated as group A, and those after the stable point were designated group B. Operative time decreased as the number of cases increased. A stable point was noticed on the 400th day and the 34th case after the first BE-LIF was performed. All cases showed improved ODI and VAS scores at the final follow-up. Overall mean operative time was 171.74 ± 35.1 min. Mean operative time was significantly lower in group B (139.7 ± 11.6 min) compared to group A (193.4 ± 28.3 min). Time to ambulation was significantly lower in group B compared to group A. VAS and ODI scores did not differ between the two groups. BE-LIF is an effective minimally invasive technique for lumbar degenerative disease. In our case series, this technique required approximately 34 cases to reach an adequate performance level.

Safety Evaluation of Biportal Endoscopic Lumbar Discectomy: Assessment of Cervical Epidural Pressure During Surgery.

STUDY DESIGN: A prospective study. OBJECTIVE: To evaluate the change in cervical epidural pressure (CEP) during biportal endoscopic lumbar discectomy (BELD). SUMMARY OF BACKGROUND DATA: In percutaneous uniportal endoscopic lumbar discectomy, irrigation fluid (IF) introduced into the spinal canal during surgery can compress the thecal sac, and act as a potential risk for neurological complications by disturbing cerebrospinal fluid (CSF) circulation and increasing intracranial pressure. METHODS: Thirty consecutive patients, who underwent BELD, which was performed under automated pump system, an infusion pressure of 30 mmHg were enrolled. The change in CEP on C7-T1 level was measured. CEP was measured in each of the five phases of the procedure (1st phase-making surgical portals; 2nd phase-creating a workspace; 3rd phase-performing neural decompression and discectomy; 4th phase-factitious increase of pressure by clogging the outflow; 5th phase-dismission from fluid irrigation system). Neurological complications and independent risk factors were evaluated. RESULTS: In the final 27 patients, changes in CEP during surgery were similar. The baseline CEP was 14.8 ±â€Š2.8 mmHg, and the mean CEP in the 3rd phase 18.8 ±â€Š5.1 mmHg was not significantly higher. In the 4th phase, however, the CEPs rose with linear correlation as the pressure increased. In the 5th phase, the elevated CEP returned to baseline in 2.5 ±â€Š5.6 minutes. No patient had neurological complications. No statistically significant risk factors were observed. CONCLUSION: In BELD, which is performed to allow continuous lavage with infusion pressure set to 30 mmHg, CEP does not increase beyond the physiological range. Therefore, BELD may be considered as a potentially safe technique. LEVEL OF EVIDENCE: 4.

Effectiveness of Gelatin-Thrombin Matrix Sealants (Floseal®) on Postoperative Spinal Epidural Hematoma during Single-Level Lumbar Decompression Using Biportal Endoscopic Spine Surgery: Clinical and Magnetic Resonance Image Study.

BACKGROUND: Symptomatic postoperative spinal epidural hematoma (PSEH) is a devastating complication that could develop after lumbar decompression surgery. PSEH can also develop after biportal endoscopic spine surgery (BESS), one of the recently introduced minimally invasive spine surgery techniques. Gelatin-thrombin matrix sealant (GTMS) is commonly used to prevent PSEH. This study aimed at analyzing the clinical and radiological effects of GTMS use during BESS. METHODS: A total of 206 patients with spinal stenosis who underwent decompression by BESS through a posterior interlaminar approach from October 2015 to September 2018 were enrolled in this study. Postoperative magnetic resonance imaging (MRI) was performed in all patients for evaluation of PSEH. Patients in whom GTMS was not used during surgery were assigned to Group A, and those in whom GTMS was used were classified as Group B. In the clinical evaluation, the visual analog scale (VAS) of the leg and back, Oswestry Disability Index (ODI), and modified MacNab criteria were used. The incidence rate and degree of dural compression of PSEH on postoperative MRI were measured. RESULTS: The average age of the patients was 68.1 ± 11.2 (42-89) years. The overall incidence rate of PSEH was 20.9% (43/206). The incidence rates in Groups A and B were 26.4% and 13.6%, respectively, showing a significant difference (p = 0.023). The VAS-leg and ODI improvement was significantly different depending on the intraoperative use of GTMS. However, there was no statistically significant difference between the two groups in terms of the VAS-back improvement. Groups A and B showed "good" and "excellent" rates according to the modified MacNab criteria in 79.4% and 87.6% of patients, respectively, showing statistically significant difference (p = 0.049). In Group A, two patients underwent revision surgery due to PSEH, while none in Group B had such event. CONCLUSION: Intraoperative use of GTMS during BESS may be related to reduction in the occurrence rate of PSEH. Specifically, patients with GTMS appliance showed marked decrease in the occurrence of PSEH and had better clinical outcomes.

Risk Factors and Options of Management for an Incidental Dural Tear in Biportal Endoscopic Spine Surgery.

STUDY DESIGN: Here we perform a retrospective analysis regarding an incidental dural tear (IDT) during biportal endoscopic spinal surgery (BESS). PURPOSE: This study investigates the causes of IDT specifically related to technical procedures of BESS with the aim of lowering its risk during training. OVERVIEW OF LITERATURE: The incidence of dural tear is reported 0.5%-18% in open spinal surgery and 1.7%-4.3% during endoscopic spinal surgery. Because conversion to open surgery for direct repair could become necessary during endoscopic spinal surgery, prevention of this complication is essential. METHODS: We have retrospectively studied IDTs by four surgeons during 1 or 2 years after starting BESS for lumbar degenerative diseases and analyzed the locations, sizes, and specific endoscopic conditions specific to each. RESULTS: Twenty-five cases (1.6%) of IDTs among 1,551 cases of BESS occurred; 13 cases (52%) of these were within the first 6 months. The locations were dorsal midline in 12 cases, ipsilateral side in 11 cases, and contralateral side in two cases. The tear sizes were <10 mm in 20 cases and ≥10 mm in five cases. IDT commonly occurred due to injury of central dural folding during flavectomy under turbid surgical fields due to small bleeds under water. Twenty cases with IDTs of <10 mm were treated well with the patch technique. Among five cases of ≥10 mm, three underwent open repair within a few days, and two of these which failed to conservative management required a delayed revision operation due to pseudomeningocele. No cases progressed to surgical site infection or infectious spondylitis. CONCLUSIONS: IDTs of <10 mm can be successfully treated with the patch technique. To prevent IDT during the early learning period, maintaining clear visibility by securing fluent saline outflow and meticulous hemostasis of small bleeding from exposed cancellous bone and epidural vessels is essential with caution not to injure the central dural folding during midline flavectomy.

Pseudomeningocele after biportal endoscopic spine surgery: A case report.

BACKGROUND: Biportal endoscopic spinal surgery (BESS) was recently introduced and became prevalent fast. Incidental dural tear (IDT) could happen as one of the common complications even in endoscopic spine surgery. CASE DESCRIPTION: A 45-year old male underwent discectomy by BESS. IDT sized about 15mm at the dorsal surface of dura occurred during the laminotomy procedure with an osteotome. Revision surgery was planned for assuming that the IDT is small enough to be sealed with a patch. CONCLUSION: Revision surgery using BESS for a small-sized IDT could be reasonable alternative treatment to preserve the soft tissue, the primary purpose of MISS.

A review of performance indicators of single-item alcohol screening questions in clinical and population settings.

Screening and brief intervention (SBI) for unhealthy alcohol use is recommended as a routine clinical procedure for adults in primary care settings. However, implementation of SBI remains suboptimal, in part reflecting time constraints in clinical settings. Single Item Screening Questions (SISQ) have increasingly been studied as a means of minimizing assessment burden. Although the ability of SISQ to accurately detect unhealthy alcohol use (i.e., at-risk drinking or alcohol use disorder) has been studied in various clinical and population settings, results have not been summarized in aggregate. This descriptive summarizes SISQ performance metrics across various clinical settings and populations. Based on results from 40 identified studies, there is consistent support that SISQ have good sensitivity as screeners for unhealthy drinking, with performance generally being comparable to longer validated instruments. Collectively, these results justify further efforts to evaluate SISQ as a means of maximizing SBI uptake and efficiency in various clinical settings.

Pharmacological inhibition of androgen receptor expression induces cell death in prostate cancer cells.

The androgen receptor (AR) plays an important role in the pathogenesis and development of prostate cancer (PCa). Mostly, PCa progresses to androgen-independent PCa, which has activated AR signaling from androgen-dependent PCa. Thus, inhibition of AR signaling may be an important therapeutic target in androgen-dependent and castration-resistant PCa. In this study, we determined the anticancer effect of a newly found natural compound, sakurasosaponin (S-saponin), using androgen-dependent and castration-resistant PCa cell lines. S-saponin induces mitochondrial-mediated cell death in both androgen-dependent (LNCaP) and castration-resistant (22Rv1 and C4-2) PCa cells, via AR expression. S-saponin treatment induces a decrease in AR expression in a time- and dose-dependent manner and a potent decrease in the expression of its target genes, including prostate-specific antigen (PSA), transmembrane protease, serin 2 (TMPRSS2), and NK3 homeobox 1 (NKX3.1). Furthermore, S-saponin treatment decreases B-cell lymphoma-extra large (Bcl-xL) and mitochondrial membrane potential, thereby increasing the release of cytochrome c into the cytosol. Moreover, Bcl-xL inhibition and subsequent mitochondria-mediated cell death caused by S-saponin were reversed by Bcl-xL or AR overexpression. Interestingly, S-saponin-mediated cell death was significantly reduced by a reactive oxygen species (ROS) scavenger, N-acetylcystein. Animal xenograft experiments showed that S-saponin treatment significantly reduced tumor growth of AR-positive 22Rv1 xenografts but not AR-negative PC-3 xenografts. Taken together, for the first time, our results revealed that S-saponin induces mitochondrial-mediated cell death in androgen-dependent and castration-resistant cells through regulation of AR mechanisms, including downregulation of Bcl-xL expression and induction of ROS stress by decreasing mitochondrial membrane potential.

Clinical and radiological outcomes between biportal endoscopic decompression and microscopic decompression in lumbar spinal stenosis.

BACKGROUND CONTEXT: Numerous minimal invasive techniques treating lumbar spinal stenosis have been introduced. Clinical results using biportal endoscopic spinal surgery has recently been introduced as a treatment option for lumbar spinal stenosis. The purpose of this study was to compare the clinical and radiologic outcome between microscopic unilateral laminotomy bilateral decompression and biportal endoscopic unilateral laminotomy bilateral decompression in patients with degenerative lumbar spinal stenosis. METHOD: A total of 89 patients were evaluated for this study. Only single-level patients were enrolled for accurate comparison. Patients that underwent biportal endoscopic surgery were assigned to Group A, and patients that underwent microscopic surgery were designated Group B. Clinical outcomes were evaluated using modified Macnab criteria, Oswestry Disability Index, and Visual Analog Scale. Postoperative complications were checked until final follow up. Plain radiographs before and after surgery were compared to analyze the change of alignment. RESULT: There was a significant difference between Group A and B in VAS of back on postoperative 2 months. Other clinical measurements except for postoperative 2 months VAS of back showed no significant difference. There were no significant differences between Group A and Group B regarding preoperative and postoperative radiological findings. CONCLUSION: Two different decompression techniques preserve the spinal structure and exhibit a favorable clinical outcome and have the advantage of not causing postoperative instability in the short term follow up. Biportal endoscopic surgery may leads to less postoperative back pain than microscopic surgery, which may allow early ambulation and shorter hospitalization period.

Risk Factors of Postoperative Spinal Epidural Hematoma After Biportal Endoscopic Spinal Surgery.

BACKGROUND: Although postoperative spinal epidural hematoma is a rare complication, it can cause severe neurologic complications. Studies regarding biportal endoscopic spinal surgery, a type of minimally invasive spinal surgery technique, have been recently reported. The purpose of our study is to report the incidence and risk factors of postoperative hematoma after biportal endoscopic spinal surgery. METHODS: The subjects included 310 patients that underwent biportal endoscopic spinal surgery from 2015 to 2017. Magnetic resonance imaging (MRI) was performed in all patients before surgery, and also after surgery to identify epidural hematoma. Using electronic medical records, perioperative factors such as age, sex, operation name, operation level, water infusion pump usage, thrombin-containing hemostatic agent, and anticoagulant medication were statistically analyzed in the aspect of postoperative hematoma. RESULTS: The overall occurrence rate of postoperative hematoma was 23.6% (n = 94). A total of 304 levels (76.4%) were without hematoma according to the postoperative MRI among the total 398 levels. Six patients underwent revision surgery of hematoma evacuation. Female sex, old age (>70 years), preoperative anticoagulation medication, and usage of intraoperative water infusion pump were significantly correlated to the occurrence of postoperative hematoma. CONCLUSIONS: Although symptomatic postoperative hematoma was extremely rare at 1.9%, radiologic hematoma confirmed by postoperative MRI was higher at 23.6%. The perioperative risk factors of postoperative hematoma after biportal endoscopic spinal surgery include female sex, older age (>70 years), preoperative anticoagulation medication, usage of intraoperative water infusion pump, and surgery requiring more bone work (laminectomy or interbody fusion).

Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis.

Biportal endoscopic spinal surgery (BESS) is a minimally invasive spinal surgery, which is basically similar to microscopic spinal surgery in terms of the use of floating technique and technically similar to conventional percutaneous endoscopic spinal surgery in terms of the use of endoscopic or arthroscopic instruments. Using two independent portals (viewing and working) and maintaining a certain distance from the bony and neural structures allow closer access to the target lesion through a panoramic view by free handling of the scope and instruments rather than through a fixed view by docking into the Kambin's triangle. Minimally invasive surgery allows for reduced dissection and inevitable muscle injury, preserving stability and reducing risks of restabilization. The purpose of fusion surgery is the same as that of the three surgical techniques stated above. Its wider range of view helps to overcome limitations of conventional endoscopic spinal surgery and to supplement the weak points of microscopic spinal surgery, such as limited working space in a tubular retractor and difficulty in accessing the contralateral area. This technique provides an alternative to unilateral or bilateral decompression of lumbar central spinal stenosis, foraminal stenosis, low-grade spondylolisthesis, and adjacent segment degeneration. Early clinical outcomes are promising despite potential for complications, such as dural tearing and postoperative epidural hematoma, similar to other procedures. Merits of BESS include decreased postoperative infection rate due to continuous irrigation throughout the procedure and decreased need for fusion surgery for one- or two-level lumbar stenosis by wide sublaminar and foraminal decompression with minimal sacrifice of stabilizing structures.

Efficacy of Biportal Endoscopic Spine Surgery for Lumbar Spinal Stenosis.

BACKGROUND: Biportal endoscopic spine surgery (BESS) is a recent addition to minimally invasive spine surgery treatments. It boasts excellent magnification and fine discrimination of neural structures. Selective decompression with preservation of facet joints for structural stability is also feasible owing to access to the spinal canal and foramen deeper inside. This study has a purpose to investigate clinical benefits of BESS for spinal stenosis in comparison to the other common surgical treatments such as microscopic decompression-only (DO) and fusion and instrumentation (FI). METHODS: From December 2013 to March 2015, 30 cases of DO, 48 cases of FI, and 66 consecutive cases of BESS for lumbar spinal stenosis (LSS) were enrolled to evaluate the relative clinical efficacy of BESS. Visual analog scale (VAS) for back pain and leg pain, postoperative hemoglobin, C-reactive protein (CRP) changes, transfusion, and postoperative complications were examined. RESULTS: All the patients were followed up until 6 months, and 98 patients (86.7%) for 2 years. At the 6-month follow-up, VAS for back pain improved from 6.8 to 2.8, 6.8 to 3.2, and 6.8 to 2.8 (p = 0.078) for BESS, DO, and FI, respectively; VAS for leg pain improved from 6.3 to 2.2, 7.0 to 2.5, and 7.2 to 2.5 (p = 0.291), respectively. Two cases in the BESS group underwent additional foraminal decompression, but no fusion surgery was performed. Postoperative hemoglobin changes for BESS, DO, and FI were -2.5, -2.4, and -1.3 mL, respectively. The BESS group had no transfusion cases, whereas 10 cases (33.3%) in DO and 41 cases (85.4%) in FI had transfusion (p = 0.000). CRP changes for BESS, DO, and FI were 0.32, 6.53, and 6.00, respectively, at day 2 postoperatively (p = 0.000); the complication rate for each group was 8.6% (two dural tears and one root injury), 6.7% (two dural tears), and 8.3% (two dural tears and two wound infections), respectively. CONCLUSIONS: BESS for LSS showed clinical results not inferior to those of the other open surgery methods in the short-term. Stable hemodynamic changes with no need for blood transfusion and minimal changes in CRP were thought to cause less injury to the back muscles with minimal bleeding. Foraminal stenosis decompression should be simultaneously conducted with central decompression to avoid an additional surgery.

Evaluation of Postoperative Spinal Epidural Hematoma After Biportal Endoscopic Spine Surgery for Single-Level Lumbar Spinal Stenosis: Clinical and Magnetic Resonance Imaging Study.

BACKGROUND: Symptomatic postoperative spinal epidural hematoma is a serious complication that may occur after lumbar spine surgery. We analyzed epidural hematoma using postoperative magnetic resonance imaging (MRI) after biportal endoscopic spinal surgery and its impact on clinical outcome. METHODS: The subjects of this study were 158 patients who underwent single-level decompression using the biportal endoscopic spinal surgery technique from 2015 to 2017. MRI was performed in all patients before and after surgery, and postoperative MRI was used to identify epidural hematoma. The preoperative and postoperative visual analog scale (VAS) score for leg and back pain, Oswestry Disability Index (ODI), and modified Macnab criteria were recorded for evaluation of clinical outcome. The group with postoperative spinal epidural hematoma (group A) and without hematoma (group B) were comparatively analyzed, both radiologically and clinically. RESULTS: The mean age of the patients was 67.9 ± 11.1 years (range, 49-89). The total number with grade 0 (no hematoma) was 119 levels patients (75.3%) on the T2 axial image of postoperative MRI. The total number of patients with hematoma was 39 (24.7%) according to T2-weighted axial postoperative MRI. Two patients underwent revision surgery because of hematoma-related symptoms. The improvement of clinical outcome measures including VAS leg, VAS back, and ODI was significantly different between group A and B (P < 0.05). CONCLUSIONS: The incidence of postoperative spinal epidural hematoma after biportal endoscopic spinal surgery according to postoperative MRI was higher than expected, regardless of the patients' postoperative symptoms. Postoperative hematoma has a decisive influence on postoperative results, and revision surgery might be necessary if canal encroachment is >50% with concomitant symptoms.

Clinical and Radiological Outcomes of Foraminal Decompression Using Unilateral Biportal Endoscopic Spine Surgery for Lumbar Foraminal Stenosis.

BACKGROUND: Since open Wiltse approach allows limited visualization for foraminal stenosis leading to an incomplete decompression, we report the short-term clinical and radiological results of unilateral biportal endoscopic foraminal decompression using 0° or 30° endoscopy with better visualization. METHODS: We examined 31 patients that underwent surgery for neurological symptoms due to lumbar foraminal stenosis which was refractory to 6 weeks of conservative treatment. All 31 patients underwent unilateral biportal endoscopic far-lateral decompression (UBEFLD). One portal was used for viewing purpose, and the other was for surgical instruments. Unilateral foraminotomy was performed under guidance of 0° or 30° endoscopy. Clinical outcomes were analyzed using the modified Macnab criteria, Oswestry disability index, and visual analogue scale. Plain radiographs obtained preoperatively and 1 year postoperatively were compared to analyze the intervertebral angle (IVA), dynamic IVA, percentage of slip, dynamic percentage of slip (gap between the percentage of slip on flexion and extension views), slip angle, disc height index (DHI), and foraminal height index (FHI). RESULTS: The IVA significantly increased from 6.24° ± 4.27° to 6.96° ± 3.58° at 1 year postoperatively (p = 0.306). The dynamic IVA slightly decreased from 6.27° ± 3.12° to 6.04° ± 2.41°, but the difference was not statistically significant (p = 0.375). The percentage of slip was 3.41% ± 5.24% preoperatively and 6.01% ± 1.43% at 1-year follow-up (p = 0.227), showing no significant difference. The preoperative dynamic percentage of slip was 2.90% ± 3.37%; at 1 year postoperatively, it was 3.13% ± 4.11% (p = 0.720), showing no significant difference. The DHI changed from 34.78% ± 9.54% preoperatively to 35.05% ± 8.83% postoperatively, which was not statistically significant (p = 0.837). In addition, the FHI slightly decreased from 55.15% ± 9.45% preoperatively to 54.56% ± 9.86% postoperatively, but the results were not statistically significant (p = 0.705). CONCLUSIONS: UBEFLD using endoscopy showed a satisfactory clinical outcome after 1-year follow-up and did not induce postoperative segmental spinal instability. It could be a feasible alternative to conventional open decompression or fusion surgery for lumbar foraminal stenosis.

Unilateral Biportal Endoscopic Spinal Surgery Using a 30° Arthroscope for L5-S1 Foraminal Decompression.

Foraminal decompression using a minimally invasive technique to preserve facet joint stability and function without fusion reportedly improves the radicular symptoms in approximately 80% of patients and is considered one of the good surgical treatment choices for lumbar foraminal or extraforaminal stenosis. However, proper decompression was not possible because of the inability to access the foramen at the L5-S1 level due to prominence of the iliac crest. To overcome this challenge, endoscopy-based minimally invasive spine surgery has recently gained attention. Here, we report the technical skills required in unilateral extraforaminal biportal endoscopic spinal surgery using a 30° arthroscope to enable foraminal decompression at the L5-S1 level. Two 0.8-cm portals were created 2 cm lateral from the lateral border of the pedicles at the L5-S1 level. After sufficient working space was made, half of the superior articular process (SAP) in the hypertrophied facet joint was removed using a high-speed burr and a 5-mm wide osteotome, whereas the remaining inside part of the SAP was removed using a Kerrison punch and pituitary punch. The foraminal ligamentum flavum should be removed to inspect the conditions of the L5 exiting root and disc. Removing of the extruded disc could decompress the L5 root. The extraforaminal approach using a 30° arthroscope is considered a minimally invasive alternative technique for decompressing foraminal stenosis at the L5-S1 level that preserves facet stability and provides symptomatic relief.