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Conventional open laminectomy has long been considered one of the important surgical options for lumbar central stenosis owing to its positive outcomes. However, newer approaches have emerged as alternatives, including full-endoscopic and biportal endoscopic laminectomy. Therefore, a comparison of the outcomes that are associated with each of these surgical methods is warranted. This prospective multicenter trial, initiated in February 2019, compared the outcomes of three lumbar central stenosis surgical approaches: open laminectomy (OPEN), uniportal endoscopy (UNIPORT), and biportal endoscopy (BIPORT). Among 115 participants from seven centers, one-year follow-ups assessed laboratory, radiological, and clinical outcomes. Despite all groups showing adequate decompression and clinical improvement, the OPEN group exhibited less improvement in Visual analog scale (VAS) for back pain scores (p < 0.05) and significant postoperative increases in most laboratory markers. Furthermore, the OPEN group experienced a significant decrease in multifidus muscle cross-sectional area compared to endoscopic groups (p < 0.001). Each surgical techniques produced similar clinical outcomes and dural space expansion. However, endoscopic surgery was associated with better muscle preservation and better relief of back pain. Endoscopic surgery is a reasonable alternative to conventional laminectomy for treating lumbar central stenosis. This trial was registered on CRIS (Clinical Research Information Service, KCT0004355).

Backgrounds Although open lumbar discectomy is a gold standard surgical technique for lumbar disc herniation (LDH), surgery-induced tissue injury may actually become a source of postsurgical pain. Percutaneous endoscopic lumbar discectomy (PELD) is introduced as a minimal invasive spinal technique for LDH. The PELD has gained popularity and shown successful results. The authors report the clinical usefulness of the PELD technique in two patients with the serial multilevel LDHs. Case presentations A 32-year-old man suffered from radicular pain at the L5 dermatome due to the down migrated soft LDH at the L4–5 level. The PELD was performed to remove the ruptured fragments, yielding a complete decompression of the L5 nerve root. Four years later, he visited the clinic because of right leg radiating pain along the S1 dermatome. An MRI scan revealed the LDH at the L5-S1 level. The PELD with foraminoplasty was also performed successfully at the L5-S1 level. Two months after the second PELD, he visited the clinic again because of severe pain along the left L4 dermatome; consequently, the PELD was also performed at the L3–4 level without any complications. A 34-year-old man presented with radiating pain in the back and both legs at the L5 dermatome. The MR images show a disc extrusion at the L4–5. The patient underwent the PELD at the L4–5 via the left approach. After the PELD, the back and leg pain both improved. One year later, the patient suffered from severe pain in the back and the left anterior thigh. The MR images show a left paramedian LDH at the L2–3. After the PELD was performed at the L2–3, the pain was relieved. The final MR images show no signs of any aggravated degeneration of the intervertebral discs or the facet joints at all of the treated levels. Conclusion When multiple episodes of LDH occur in a patient’s life span, PELD could be considered as an alternative good technique to treat LDH in each step by preserving normal anatomic structures.

Background Recent studies on biportal endoscopic spine surgery in patients with lumbar spinal stenosis have reported good clinical results. However, these studies have been limited by the small sample sizes and use of a retrospective study design. Therefore, we aim to compare the efficacy and safety of biportal endoscopic decompressive laminectomy with those of conventional decompressive laminectomy in a multicenter, prospective, randomized controlled trial. Methods This study will include 120 patients (60 per group, aged 20–80 years) with 1- or 2-level lumbar spinal stenosis, who will be recruited from six hospitals. The study will be conducted from July 2021 to December 2024. The primary outcome (Oswestry Disability Index at 12 months after surgery) will be evaluated through a modified intention-to-treat method. The secondary outcomes will include the following: visual analog scale score for low back and lower extremity radiating pain, EuroQol 5-dimensions score, surgery satisfaction, walking time, postoperative return to daily life period, postoperative surgical scars, and some surgery-related variables. Radiographic outcomes will be analyzed using magnetic resonance imaging or computed tomography. All outcomes will be evaluated before the surgery and at 2 weeks, 3 months, 6 months, and 12 months postoperatively. This protocol adheres to the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines for reporting of clinical trial protocols. Discussion It is hypothesized that the efficacy and safety of biportal endoscopic and conventional decompressive laminectomy will be comparable in patients with lumbar spinal stenosis. The results of this trial will provide a high level of evidence for the efficacy and safety of the biportal endoscopic technique in patients with lumbar spinal stenosis and facilitate the development of clinical practice guidelines. Furthermore, the results of this study may indicate the feasibility of the biportal endoscopic technique for other types of spinal surgery. Trial registration The ENDO-B trial is registered at Clinical Research Information Service (CRIS, cris.nih.go.kr ) (KCT0006057; April 52,021).

Background: Percutaneous transforaminal techniques for the treatment of lumbar disc herniation have markedly evolved. Percutaneous endoscopic lumbar discectomy (PELD) for L5-S1 disc herniation is regarded as challenging due to the unique anatomy of the iliac crest, large facet joint, and inclinatory disc space. Among these, the iliac crest is considered a major obstacle. There are no studies regarding the height of the iliac crest and their appropriate procedures in PELD. Objectives: This study discusses PELD for L5-S1 disc herniation and the appropriate approach according to the height of iliac crest. Study Design: Retrospective evaluation. Methods: 100 consecutive patients underwent PELD via the transforaminal route for L5-S1 disc herniation by a single surgeon. The study was divided into 2 groups: the foraminoplasty group requiring foraminal widening to access the herniated disc and the non-foraminoplasty group treated by conventional posterolateral access. Radiological parameters such as iliac height, the relative position of the iliac crest to the landmarks of the L5-S1 level, iliosacral angle and foraminal height, and disc location were considered. Clinical outcomes were assessed by the Visual Analogue Scale (VAS, 0 – 10) for back and leg pain, the Oswestry Disability Index (ODI, 0 – 100%), and the modified MacNab criteria. Results: The overall VAS scores for back and leg pain decreased from 6.0 to 2.3 and from 7.5 to 1.7. The mean ODI (%) improved from 54.0 to 11.6. Using modified MacNab criteria, a good outcome was 92%. Foraminoplasty was required in 19 patients. Iliac crest height was significantly higher in the foraminoplasty group than the non-foraminoplasty group (37.7 mm vs 30.1 mm, P < 0.001). In the foraminoplasty group, the iliac crest is above the mid L5 pedicle on lateral radiography in all cases. There were no significant differences in foraminal height, foraminal width, iliosacral angle, or disc height between the 2 groups. In addition, there were no differences in clinical outcome between the 2 groups. Limitations: This study is a retrospective analysis and simplifies the complexity of the L5-S1 level and iliac bone using two-dimensional radiography. Conclusion: In high iliac crest cases where the iliac crest is above the mid L5 pedicle in lateral radiography, foraminoplasty may be considered for transforaminal access of L5-S1 disc herniation. Conventional transforaminal access can be utilized with ease in low iliac crest cases where the iliac crest is below the mid-L5 pedicle. Key words: Percutaneous endoscopic lumbar discectomy, transforaminal, L5-S1, iliac crest, foraminoplasty

Magnetized water is defined as the amount of water that has passed through a magnet. The magnetic field weakens the hydrogen bonds between the water molecules, leading to the magnetized liquid acquiring special characteristics such as easy supercooling and forming smaller ice crystals. We researched the influences of a magnetized freezing extender on cell membrane damage and in vitro fertilization of boar sperm during cryopreservation. The freezing extenders were passed through 0, 2000, 4000, and 6000 gausses (G) of magnetic devices using a liquid cycling pump system and then used for the sperm freezing process. The damage to plasma, acrosomal, and mitochondrial membranes in frozen-thawed spermatozoa was investigated by flow cytometry, and motility was assessed using the CASA system. The fertility of frozen-thawed sperm was estimated using in vitro fertilization. The damage to the membranes was significantly decreased in the magnetized freezing extender by the 6000 G magnetic field compared to that of the control in frozen-thawed sperm, and motility was increased in the 6000 G group. Although there were no significant differences in the cleavage rates of in vitro fertilized oocytes among the treatment groups, the ratio of blastocyst formation increased in the magnetized freezing extender groups compared with that in the control group. The number of blastocysts was significantly higher in the 4000 G group than in the 0 G group. In conclusion, these results suggest that a magnetized freezing extender could improve the freezability of sperm and the development of oocytes fertilized in vitro with frozen-thawed sperm.

Background: Remarkable advancements in endoscopic spinal surgery have led to successful outcomes comparable to those of conventional open surgery. Large lumbar disc herniation (LLDH) is a serious condition, resulting in higher surgical failure when accessing the herniated disc. Objectives: This study compared the outcomes of LLDH treated with percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM). Study Design: Retrospective assessment. Methods: This retrospective observational study was conducted from January 2011 to June 2012. Forty-four consecutive patients diagnosed with LLDH without cauda equina syndrome who were scheduled to undergo spinal surgery were included. LLDH was defined as herniated disc fragment occupying > 50% of the spinal canal. Clinical outcomes were evaluated using a visual analogue scale (VAS, 0 – 10), functional status was assessed using the Oswestry Disability Index (ODI, 0 – 100%) at 1, 6, and 24 months postoperatively and surgical satisfaction rate (0 – 100%) at final follow up. Radiological variables were assessed by plain radiography. Results: Forty-three patients were included; 20 and 23 patients underwent PELD and OLM, respectively. Both groups exhibited significant improvements in leg and back pain postoperatively (P < 0.001). Although there was no significant difference in leg pain improvement between the groups, improvement in back pain was significantly higher in the PELD group than in the OLM group (4.9 ± 1.5 vs. 2.5 ± 1.0, P < 0.001). The surgical satisfaction rate of the PELD group was significantly higher than that of the OLM group (91.3% ± 6.5 vs. 84.3% ± 5.2, P < 0.001). Mean operating time, hospital stay, and time until return to work were significantly shorter in the PELD group than in the OLM group (67.8 vs. 136.7 minutes, 1.5 vs. 7.2 days, and 4.2 vs. 8.6 weeks; P < 0.001). Disc height (%) decreased significantly from 23.7 ± 3.3 to 19.1 ± 3.7 after OLM (P < 0.001), but did not change significantly after PELD (23.6 ± 3.2 to 23.4 ± 4.2; P = 0.703). The segmental angle of the operated level increased from 10.3° to 15.4° in the PELD group, which was significantly higher than that in the OLM group (9.6° to 11.6°; P = 0.038). In the OLM group, there was one case of fusion due to instability. In the PELD group, one case required revision surgery and another case experienced recurrence. There were no perioperative complications in either group. Limitation: The study was retrospective with a small sample size and short follow-up period. Conclusion: PELD can be an effective treatment for LLDH, and it is associated with potential advantages, including a rapid recovery, improvements in back pain, and disc height preservation. Key words: Large lumbar disc herniation, percutaneous endoscopic lumbar discectomy, microdiscectomy, back pain, disc height

Embryonic stem cells (ESCs) derived from outbred mice which share several genetic characteristics similar to humans have been requested for developing stem cell-based bioengineering techniques directly applicable to humans. Here, we report the generation of ESCs derived from the inner cell mass of blastocysts retrieved from 9-week-old female outbred ICR mice mated with 9-week-old male outbred ICR mice ( ICR ESCs). Similar to those from 129/Ola mouse blastocysts ( E14 ESCs), the established ICR ESCs showed inherent characteristics of ESCs except for partial and weak protein expression and activity of alkaline phosphatase. Moreover, ICR ESCs were not originated from embryonic germ cells or pluripotent cells that may co-exist in outbred ICR strain-derived mouse embryonic fibroblasts ( ICR MEFs) used for deriving colonies from inner cell mass of outbred ICR mouse blastocysts. Furthermore, instead of outbred ICR MEFs, hybrid B6CBAF1 MEFs as feeder cells could sufficiently support in vitro maintenance of ICR ESC self-renewal. Additionally, ICR ESC-specific characteristics (self-renewal, pluripotency, and chromosomal normality) were observed in ICR ESCs cultured for 40th subpassages (164 days) on B6CBAF1 MEFs without any alterations. These results confirmed the successful establishment of ESCs derived from outbred ICR mice, and indicated that self-renewal and pluripotency of the established ICR ESCs could be maintained on B6CBAF1 MEFs in culture.

The aim of the present study was to investigate the effects of porcine follicular fluid (pFF) from large-sized (LFF; >8 mm in diameter) and medium-sized (MFF; 3–6 mm in diameter) follicles on the maturation and developmental competence of porcine oocytes. Cumulus–oocyte complexes (COCs) were collected from follicles 3–6 mm in diameter. The collected COCs were incubated for 22 h with LFF or MFF ( in vitro maturation (IVM)-I stage) and were incubated subsequently for 22 h with LFF or MFF (IVM-II stage). Cumulus expansion was confirmed after the IVM-I stage and nuclear maturation was evaluated after the IVM-II stage. Intracellular glutathione (GSH) and reactive oxygen species (ROS) levels were measured and embryonic development was evaluated. Relative cumulus expansion and GSH levels were higher in the LFF group compared with in the MFF group after the IVM-I stage ( P < 0.05). After the IVM-II stage, the numbers of oocytes in metaphase-II were increased in the LFF group and GSH content was higher in all of the LFF treatment groups compared with in the MFF treatment groups during both IVM stages ( P < 0.05). ROS levels were reduced by LFF treatment regardless of IVM stage ( P < 0.05). Blastocyst formation and the total numbers of cells in blastocysts were increased in all LFF treatment groups compared with the control group ( P < 0.05). These results suggested that pFF from large follicles at the IVM stage could improve nucleic and cytoplasmic maturation status and further embryonic development through reducing ROS levels and enhancing responsiveness to gonadotropins.

Background: Osteoporosis is an important problem in those of advanced age. Osteoporosis can induce sacral insufficiency fractures (SIFs). As average life expectancy increases, the number of patients with osteoporotic SIFs also increases. Osteoporotic SIFs cause severe low back pain and immobilization. Treatment of SIFs varies from analgesia to surgery. Objectives: To describe our experience and assess the safety and effectiveness of minimally invasive percutaneous sacroplasty in patients with osteoporotic SIFs. Study Design: Retrospective evaluation. Setting: The spine and joint specialized hospital’s research center. Methods: We reviewed cases of percutaneous sacroplasty performed since 2009. We used data only from patients with osteoporotic SIFs who were followed for more than 12 months after sacroplasty. Tumor-related SIFs were excluded from our analysis. The following clinical parameters were investigated: initial diagnosis, symptoms, visual analog scale (VAS) of pain, functional mobility scale (FDC) score, past history of illness, amount of bone cement infused, and complications related to sacroplasty. Also, the following radiological parameters were analyzed: the pattern of SIFs, T-score cement leakage, and concomitant fractures in other sites. Results: Sixty-eight patients were enrolled in our study (4 men and 64 women). The mean age of the patients was 76.8 ± 6.2 years. All patients had severe osteoporosis (mean T score: -3.9 ± 0.5). Percutaneous sacroplasty was performed under fluoroscopic guidance. No major complications or procedure-related morbidity occurred. FDS and VAS scores significantly improved after sacroplasty, and the improvements lasted through the final follow-up period (P < 0.05). Limitations: This study is a retrospective analysis without a control group. Conclusion: Percutaneous sacroplasty is an effective minimally invasive treatment for osteoporotic SIFs refractory to conservative management. The study patients experienced significant relief of pain and increased mobility. Key words: Sacrum, sacroplasty, insufficiency fractures, osteoporosis, minimally invasive surgery

Although percutaneous endoscopic lumbar discectomy (PELD) is an effective treatment for herniated discs, its application in a disc with extensive migration is still challenging. As such, epiduroscopic laser neural decompression (ELND) provides a new view of the epidural space as well as an alternative treatment for a herniated disc and epidural fibrosis. In this paper the authors introduce the novel combination of PELD and ELND for high grade down-migrated disc herniation.An 87-year old woman presented with severe pain radiating down her leg due to high grade down-migrated disc herniation at L4-5. The therapeutic plan was organized into 3 steps. First, the patient underwent PELD to remove the paracentral extruded disc and open the epidural space between the traversing nerve root and disc space. Second, ELND was performed to remove the down-migrated disc and simultaneously push the free fragment to the L4-5 disc space. Lastly, repetitive free fragments were picked up and streamed upward using ELND. The patient reported significant reduction of pain after surgery. Postoperative magnetic resonance imaging (MRI) showed complete removal of the ruptured disc fragment. A combination of PELD and ELND may be an option of treatments for down-migrated disc herniation.