A Propensity Score-Matched Cohort Study Comparing 3 Different Spine Pedicle Screw Fixation Methods: Freehand, Fluoroscopy-Guided, and Robot-Assisted Techniques

OBJECTIVE

This study aimed to compare the accuracy of robotic spine surgery and conventional pedicle screw fixation in lumbar degenerative disease. We evaluated clinical and radiological outcomes to demonstrate the noninferiority of robotic surgery.

METHODS

This study employed propensity score matching and included 3 groups: robot-assisted mini-open posterior lumbar interbody fusion (PLIF) (robotic surgery, RS), c-arm guided minimally invasive surgery transforaminal lumbar interbody fusion (C-arm guidance, CG), and freehand open PLIF (free of guidance, FG) (54 patients each). The mean follow-up period was 2.2 years. The preoperative spine condition was considered. Accuracy was evaluated using the Gertzbein-Robbins scale (GRS score) and Babu classification (Babu score). Radiological outcomes included adjacent segmental disease (ASD) and mechanical failure. Clinical outcomes were assessed based on the visual analogue scale, Oswestry Disability Index, 36-item Short Form health survey, and clinical ASD rate.

RESULTS

Accuracy was higher in the RS group (p < 0.01) than in other groups. The GRS score was lower in the CG group, whereas the Babu score was lower in the FG group compared with the RS group. No significant differences were observed in radiological and clinical outcomes among the 3 groups. Regression analysis identified preoperative facet degeneration, GRS and Babu scores as significant variables for radiological and clinical ASD. Mechanical failure was influenced by the GRS score and patients' age.

CONCLUSION

This study showed the superior accuracy of robotic spine surgery compared with conventional techniques. When combined with minimally invasive surgery, robotic surgery is advantageous with reduced ligament and muscle damage associated with traditional open procedures.

Complications of Endoscopic Thoracic Spine Surgery: Overview and Complication Avoidance

In endoscopic thoracic spine surgery, adaptations of thoracic surgical techniques such as full endoscopic uniportal and biportal surgical techniques have been developed. Full endoscopic uniportal surgery for thoracic disc herniation or thoracic ossified ligamentum flavum (OLF) has been performed via transforaminal and interlaminar approaches. In the case of thoracic OLF or thoracic spinal stenosis, the uniportal interlaminar approach is appropriate. The uniportal interlaminar approach has been used to treat thoracic OLF and has shown good surgical results. Thoracic OLF removal via a biportal endoscopic technique has been developed recently and is described in a few studies. Although endoscopic thoracic spine surgery has significant advantages, complications often occur with this approach. We reviewed the literature to date on the complications associated with endoscopic spine surgery in thoracic pathology. This review emphasizes how to avoid and manage complications. Based on the results of several previous studies, endoscopic thoracic spine surgery could be associated with fewer potential complications than conventional surgery. Endoscopic spine surgery has remarkable advantages; however, endoscopic thoracic surgery is technically challenging and is potentially associated with serious complications. To minimize the risk of avoidable complications, surgeons should be familiar with prevention methods and pitfalls.

Low Tesla MR Imaging for Spine with Hardware

PURPOSE/OBJECTIVE(S)

Acquiring MR images with minimized susceptibility artifacts is essential for spines with medical hardware to delineate clinical target volumes (CTVs) in radiation therapy for chordomas, chondrosarcomas, and other sarcomas. Since it can be more challenging to visualize the primary structures in high-tesla MR images due to metal-induced artifacts, we optimized imaging parameters to acquire high-quality, low-tesla MR images for clinical use.

MATERIALS/METHODS

OptimalMR imaging parameters were investigated under general guidelines for artifact reduction techniques by testing several 3D spin echo and gradient echo sequences in a 0.23-T MR scanner. A customized spine phantom was developed to acquire MR images for bony materials which included, 4-6 industrial titanium screws, an aluminum plate, and a superflab bolus. While the 3D b-FFE sequence was used to acquire MR images with a high signal-to-noise ratio, the other 3D T1-FFE, THRIVE, and DTSE sequences were applied to reduce susceptible artifacts to the medical hardware. The optimized parameters determined in the phantom test were applied to the 15 clinical cases, including patients with residual spinal tumors and fusion hardware. The low-tesla MR imaging technique was also used to scan sarcomas of the extremities and re-irradiation cases of spinal metastases.

RESULTS

The optimized low-tesla MR images in the spine were noticeably useful to guide CTV delineations for patients with medical hardware, especially for residual or recurrent tumors. The imaging technique to minimize susceptibility artifacts enabled a more defined separation of each hardware component from the spinal cord and CTVs. In spine metastasis cases, pre-irradiated target volumes were determined, reflecting property changes in the bone marrow.

CONCLUSION

The MR images acquired using the optimized parameters showed minimal artifacts to scan spine patients with hardware. By using the low-tesla MR images, spinal chordoma and chondrosarcoma patients could be treated to improve tumor control probabilities with minimized complications.

Development of a Filtimator for Pediatric Image-Guided Radiation Therapy with Low Imaging Dose

PURPOSE/OBJECTIVE(S)

We propose to use the filtimator (a filter and a collimator) for CBCT-based image-guided radiation therapy (IGRT) optimized for pediatric patients to minimize the imaging dose but not to sacrifice the imaging quality required for bony-based image fusion.

MATERIALS/METHODS

The filtimator was made of Tin (0.6 - 1 mm) and Cu sheets (0.6 to 1.2mm) for filter and collimation with adjustable collimation with 4 to 6 cm fields at the isocenter. The thickness of the filter in the central and the peripheral regions were determined using vendor-provided image registration software and to ensure that the rigid image registration results from the CBCT were with and without the filtimator. The image quality of the filtered CBCT was compared with the regular CBCTs. Image registration accuracy was investigated by creating a < 2° shift in pitch, roll, and rotation and < 3 cm shifts in the lateral, vertical, and longitudinal directions, using commercial head and house-made phantoms. The imaging dose reduction factor of the filtimator was measured using a CT dose index phantom.

RESULTS

The contrast-to-noise ratio substantially improved in the opening region of the filter, which provided better visualization of normal anatomy and target volumes. The slim filter reduced the imaging dose by > 98% in the filtered region, and the visualization of bony structures was well preserved, allowing for accurate rigid image registration with the filter. The imaging registration difference was < 0.2° shift in pitch, roll, and rotation and < 0.5 mm shift in the lateral, vertical, and longitudinal directions compared to the regular CBCT.

CONCLUSION

The proposed dose reduction with the filtimator was demonstrated to be efficient and effective in considerably reducing the patient imaging dose while yielding accurate registration results. This novel technique can become a valuable tool for generating 3- and 4-dimensional images with a much-reduced dose to improve the precision of target localization in radiation therapy.

Optimization of the optical transparency of bones by PACT-based passive tissue clearing

Recent developments in tissue clearing methods such as the passive clearing technique (PACT) have allowed three-dimensional analysis of biological structures in whole, intact tissues, thereby providing a greater understanding of spatial relationships and biological circuits. Nonetheless, the issues that remain in maintaining structural integrity and preventing tissue expansion/shrinkage with rapid clearing still inhibit the wide application of these techniques in hard bone tissues, such as femurs and tibias. Here, we present an optimized PACT-based bone-clearing method, Bone-mPACT+, that protects biological structures. Bone-mPACT+ and four different decalcifying procedures were tested for their ability to improve bone tissue clearing efficiency without sacrificing optical transparency; they rendered nearly all types of bone tissues transparent. Both mouse and rat bones were nearly transparent after the clearing process. We also present a further modification, the Bone-mPACT+ Advance protocol, which is specifically optimized for processing the largest and hardest rat bones for easy clearing and imaging using established tissue clearing methods.

Classification of IDH wild-type glioblastoma tumorspheres into low- and high-invasion groups based on their transcriptional program

BACKGROUND

Glioblastoma (GBM), one of the most lethal tumors, exhibits a highly infiltrative phenotype. Here, we identified transcription factors (TFs) that collectively modulate invasion-related genes in GBM.

METHODS

The invasiveness of tumorspheres (TSs) were quantified using collagen-based 3D invasion assays. TF activities were quantified by enrichment analysis using GBM transcriptome, and confirmed by cell-magnified analysis of proteome imaging. Invasion-associated TFs were knocked down using siRNA or shRNA, and TSs were orthotopically implanted into mice.

RESULTS

After classifying 23 patient-derived GBM TSs into low- and high-invasion groups, we identified active TFs in each group-PCBP1 for low invasion, and STAT3 and SRF for high invasion. Knockdown of these TFs reversed the phenotype and invasion-associated-marker expression of GBM TSs. Notably, MRI revealed consistent patterns of invasiveness between TSs and the originating tumors, with an association between high invasiveness and poor prognosis. Compared to controls, mice implanted with STAT3- or SRF-downregulated GBM TSs showed reduced normal tissue infiltration and tumor growth, and prolonged survival, indicating a therapeutic response.

CONCLUSIONS

Our integrative transcriptome analysis revealed three invasion-associated TFs in GBM. Based on the relationship among the transcriptional program, invasive phenotype, and prognosis, we suggest these TFs as potential targets for GBM therapy.

Appropriateness of antibiotic use for patients with asymptomatic bacteriuria or urinary tract infection with positive urine culture: a retrospective observational multi-centre study in Korea

BACKGROUND

Antibiotic resistance threatens public health worldwide, and inappropriate use of antibiotics is one of the main causes.

AIM

To evaluate qualitative use of antibiotics in asymptomatic bacteriuria (ABU) and urinary tract infection (UTI).

METHODS

Cases of positive urine culture (≥105 colony-forning units/mL) performed in inpatient, outpatient and emergency departments in April 2021 were screened in 26 hospitals in the Republic of Korea. The cases were classified as ABU, lower UTI and upper UTI. The appropriateness of antibiotic use was evaluated retrospectively by infectious disease specialists using quality indicators based on clinical guidelines for ABU and UTI.

RESULTS

This study included a total of 2697 patients with ABU or UTI. The appropriateness of antibiotic use was assessed in 1157 patients with ABU, and in 677 and 863 patients with lower and upper UTI, respectively. Among the 1157 patients with ABU, 251 (22%) were prescribed antibiotics without appropriate indications. In 66 patients with ABU in which antibiotics were prescribed with appropriate indications, the duration was adequate in only 23 (34.8%) patients. The appropriateness of empirical and definite antibiotics was noted in 527 (77.8%) and 353 (68.0%) patients with lower UTI, and 745 (86.3%) and 583 (78.2%) patients with upper UTI, respectively. The duration of antibiotics was adequate in 321 (61.8%) patients with lower UTI and 576 (78.7%) patients with upper UTI.

CONCLUSIONS

This nationwide qualitative assessment of antibiotic use in ABU and UTI revealed that antibiotics were often prescribed inappropriately, and the duration of antibiotics was unnecessarily prolonged.

Hormonal stimulation reduces numbers and impairs function of human uterine natural killer cells during implantation

STUDY QUESTION

How does an altered maternal hormonal environment, such as that seen during superovulation with gonadotropins in ART, impact human uterine immune cell distribution and function during the window of implantation?

SUMMARY ANSWER

Hormonal stimulation with gonadotropins alters abundance of maternal immune cells including uterine natural killer (uNK) cells and reduces uNK cell ability to promote extravillous trophoblast (EVT) invasion.

WHAT IS KNOWN ALREADY

An altered maternal hormonal environment, seen following ART, can lead to increased risk for adverse perinatal outcomes associated with disordered placentation. Maternal immune cells play an essential role in invasion of EVTs, a process required for proper establishment of the placenta, and adverse perinatal outcomes have been associated with altered immune cell populations. How ART impacts maternal immune cells and whether this can in turn affect implantation and placentation in humans remain unknown.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was carried out between 2018 and 2021 on 51 subjects: 20 from natural cycles 8 days after LH surge; and 31 from stimulated IVF cycles 7 days after egg retrieval.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometrial biopsies and peripheral blood samples were collected during the window of implantation in subjects with regular menstrual cycles or undergoing superovulation. Serum estradiol and progesterone levels were measured by chemiluminescent competitive immunoassay. Immune cell populations in blood and endometrium were analyzed using flow cytometry. uNK cells were purified using fluorescence-activated cell sorting and were subjected to RNA sequencing (RNA-seq). Functional changes in uNK cells due to hormonal stimulation were evaluated using the implantation-on-a-chip (IOC) device, a novel bioengineered platform using human primary cells that mimics early processes that occur during pregnancy in a physiologically relevant manner. Unpaired t-tests, one-way ANOVA, and pairwise multiple comparison tests were used to statistically evaluate differences.

MAIN RESULTS AND THE ROLE OF CHANCE

Baseline characteristics were comparable for both groups. As expected, serum estradiol levels on the day of biopsy were significantly higher in stimulated (superovulated) patients (P = 0.0005). In the setting of superovulation, we found an endometrium-specific reduction in the density of bulk CD56+ uNK cells (P < 0.05), as well as in the uNK3 subpopulation (P = 0.025) specifically (CD103+ NK cells). In stimulated samples, we also found that the proportion of endometrial B cells was increased (P < 0.0001). Our findings were specific to the endometrium and not seen in peripheral blood. On the IOC device, uNK cells from naturally cycling secretory endometrium promote EVT invasion (P = 0.03). However, uNK cells from hormonally stimulated endometrium were unable to significantly promote EVT invasion, as measured by area of invasion, depth of invasion, and number of invaded EVTs by area. Bulk RNA-seq of sorted uNK cells from stimulated and unstimulated endometrium revealed changes in signaling pathways associated with immune cell trafficking/movement and inflammation.

LIMITATIONS, REASONS FOR CAUTION

Patient numbers utilized for the study were low but were enough to identify significant overall population differences in select immune cell types. With additional power and deeper immune phenotyping, we may detect additional differences in immune cell composition of blood and endometrium in the setting of hormonal stimulation. Flow cytometry was performed on targeted immune cell populations that have shown involvement in early pregnancy. A more unbiased approach might identify changes in novel maternal immune cells not investigated in this study. We performed RNA-seq only on uNK cells, which demonstrated differences in gene expression. Ovarian stimulation may also impact gene expression and function of other subsets of immune cells, as well as other cell types within the endometrium. Finally, the IOC device, while a major improvement over existing in vitro methods to study early pregnancy, does not include all possible maternal cells present during early pregnancy, which could impact functional effects seen. Immune cells other than uNK cells may impact invasion of EVTs in vitro and in vivo, though these remain to be tested.

WIDER IMPLICATIONS OF THE FINDINGS

These findings demonstrate that hormonal stimulation affects the distribution of uNK cells during the implantation window and reduces the proinvasive effects of uNK cells during early pregnancy. Our results provide a potential mechanism by which fresh IVF cycles may increase risk of disorders of placentation, previously linked to adverse perinatal outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported by the University of Pennsylvania University Research Funding (to M.M.), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (P50HD068157 to M.M., S.S., and S.M.), National Center for Advancing Translational Sciences of the National Institutes of Health (TL1TR001880 to J.K.), the Institute for Translational Medicine and Therapeutics of the Perelman School of Medicine at the University of Pennsylvania, the Children's Hospital of Philadelphia Research Institute (to S.M.G.), and the National Institute of Allergy and Infectious Diseases (K08AI151265 to S.M.G.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Personalized Interventional Surgery of the Lumbar Spine: A Perspective on Minimally Invasive and Neuroendoscopic Decompression for Spinal Stenosis

Pain generator-based lumbar spinal decompression surgery is the backbone of modern spine care. In contrast to traditional image-based medical necessity criteria for spinal surgery, assessing the severity of neural element encroachment, instability, and deformity, staged management of common painful degenerative lumbar spine conditions is likely to be more durable and cost-effective. Targeting validated pain generators can be accomplished with simplified decompression procedures associated with lower perioperative complications and long-term revision rates. In this perspective article, the authors summarize the current concepts of successful management of spinal stenosis patients with modern transforaminal endoscopic and translaminar minimally invasive spinal surgery techniques. They represent the consensus statements of 14 international surgeon societies, who have worked in collaborative teams in an open peer-review model based on a systematic review of the existing literature and grading the strength of its clinical evidence. The authors found that personalized clinical care protocols for lumbar spinal stenosis rooted in validated pain generators can successfully treat most patients with sciatica-type back and leg pain including those who fail to meet traditional image-based medical necessity criteria for surgery since nearly half of the surgically treated pain generators are not shown on the preoperative MRI scan. Common pain generators in the lumbar spine include (a) an inflamed disc, (b) an inflamed nerve, (c) a hypervascular scar, (d) a hypertrophied superior articular process (SAP) and ligamentum flavum, (e) a tender capsule, (f) an impacting facet margin, (g) a superior foraminal facet osteophyte and cyst, (h) a superior foraminal ligament impingement, (i) a hidden shoulder osteophyte. The position of the key opinion authors of the perspective article is that further clinical research will continue to validate pain generator-based treatment protocols for lumbar spinal stenosis. The endoscopic technology platform enables spine surgeons to directly visualize pain generators, forming the basis for more simplified targeted surgical pain management therapies. Limitations of this care model are dictated by appropriate patient selection and mastering the learning curve of modern MIS procedures. Decompensated deformity and instability will likely continue to be treated with open corrective surgery. Vertically integrated outpatient spine care programs are the most suitable setting for executing such pain generator-focused programs.

The Role and Future of Endoscopic Spine Surgery: A Narrative Review

Many types of surgeries are changing from conventional to minimally invasive techniques. Techniques in spine surgery have also changed, with endoscopic spine surgery (ESS) becoming a major surgical technique. Although ESS has advantages such as less soft tissue dissection and normal structure damage, reduced blood loss, less epidural scarring, reduced hospital stay, and earlier functional recovery, it is not possible to replace all spine surgery techniques with ESS. ESS was first used for discectomy in the lumbar spine, but the range of ESS has expanded to cover the entire spine, including the cervical and thoracic spine. With improvements in ESS instruments (optics, endoscope, endoscopic drill and shaver, irrigation pump, and multiportal endoscopic), limitations of ESS have gradually decreased, and it is possible to apply ESS to more spine pathologies. ESS currently incorporates new technologies, such as navigation, augmented and virtual reality, robotics, and 3-dimentional and ultraresolution visualization, to innovate and improve outcomes. In this article, we review the history and current status of ESS, and discuss future goals and possibilities for ESS through comparisons with conventional surgical techniques.

MicroRNA super-resolution imaging in blood for Alzheimer's disease

We propose a novel blood biomarker detection method that uses miRNA super-resolution imaging to enable the early diagnosis of Alzheimer's disease (AD). Here, we report a singlemolecule detection method for visualizing disease-specific miRNA in tissue from an AD mice model, and peripheral blood mononuclear cells (PBMCs) from AD patients. Using optimized Magnified Analysis of Proteome (MAPs), we confirmed that five miRNAs contribute to neurodegenerative disease in the brain hippocampi of 5XFAD and wild-type mice. We also assessed PBMCs isolated from the whole blood of AD patients and a healthy control group, and subsequently analyzed those samples using miRNA super-resolution imaging. We detected more miR-200a-3p expression in the cornu ammonis 1 and dentate gyrus regions of 3 month-old 5XFAD mice than in wild-type mice. Additionally, miRNA super-resolution imaging of blood provides AD diagnosis platform for studying miRNA regulation inside cells at the single molecule level. Our results present a potential liquid biopsy method that could improve the diagnosis of early stage AD and other diseases. [BMB Reports 2023; 56(3): 190-195].

Predictive risk factors for mechanical complications after multilevel posterior cervical instrumented fusion

OBJECTIVE

Mechanical complications should be considered following the correction of multilevel posterior cervical instrumented fusion. This study aimed to investigate clinical data on the patients' pre- and postoperative cervical alignment in terms of the incidence of mechanical complications after multilevel posterior cervical instrumented fusion.

METHODS

Between January 2008 and December 2018, 156 consecutive patients who underwent posterior cervical laminectomy and instrumented fusion surgery of 4 or more levels and were followed up for more than 2 years were included in this study. Age, sex, bone mineral density (BMD), BMI, mechanical complications, and pre- and postoperative radiographic factors were analyzed using multivariate logistic regression analysis to investigate the factors related to mechanical complications.

RESULTS

Of the 156 patients, 114 were men and 42 were women; the mean age was 60.38 years (range 25-83 years), and the mean follow-up duration of follow-up was 37.56 months (range 24-128 months). Thirty-seven patients (23.7%) experienced mechanical complications, and 6 of them underwent revision surgery. The significant risk factors for mechanical complications were low BMD T-score (-1.36 vs -0.58, p = 0.001), a large number of fused vertebrae (5.08 vs 4.54, p = 0.003), a large preoperative C2-7 sagittal vertical axis (SVA; 32.28 vs 23.24 mm, p = 0.002), and low preoperative C2-7 lordosis (1.85° vs 8.83°, p = 0.001). The clinical outcomes demonstrated overall improvement in both groups; however, the neck visual analog scale, Neck Disability Index, and Japanese Orthopaedic Association scores after surgery were significantly worse in the mechanical complication group compared with the group without mechanical complications.

CONCLUSIONS

Low BMD, a large number of fused vertebrae, a large preoperative C2-7 SVA, and low C2-7 lordosis were significant risk factors for mechanical complications after posterior cervical fusion surgery. The results of this study could be valuable for preoperative counseling, medical treatment, or surgical planning when multilevel posterior cervical instrumented fusion surgery is performed.

Clinical Effect of Transverse Process Hook with K-Means Clustering-Based Stratification of Computed Tomography Hounsfield Unit at Upper Instrumented Vertebra Level in Adult Spinal Deformity Patients

OBJECTIVE

This study aimed to investigate the efficacy of transverse process (TP) hook system at the upper instrumented vertebra (UIV) for preventing screw pullout in adult spinal deformity surgery using the pedicle Hounsfield unit (HU) stratification based on K-means clustering.

METHODS

We retrospectively reviewed 74 patients who underwent deformity correction surgery between 2011 and 2020 and were followed up for >12 months. Pre- and post-operative data were used to determine the incidence of screw pullout, UIV TP hook implementation, vertebral body HU, pedicle HU, and patient outcomes. Data was then statistically analyzed for assessment of efficacy and risk prediction using stratified HU at UIV level alongside the effect of the TP hook system.

RESULTS

The screw pullout rate was 36.4% (27/74). Perioperative radiographic parameters were not significantly different between the pullout and non-pullout groups. The vertebral body HU and pedicle HU were significantly lower in the pullout group. K-means clustering stratified the vertebral body HU ≥205.3, <137.2, and pedicle HU ≥243.43, <156.03. The pullout rate significantly decreases in patients receiving the hook system when the pedicle HU was from ≥156.03 to < 243.43 (p<0.05), but the difference was not statistically significant in the vertebra HU stratified groups and when pedicle HU was ≥243.43 or <156.03. The postoperative clinical outcomes improved significantly with the implementation of the hook system.

CONCLUSION

The UIV hook provides better clinical outcomes and can be considered a preventative strategy for screw-pullout in the certain pedicle HU range.

Comparison of Unilateral Biportal Endoscopic Discectomy with Other Surgical Technics: A Systemic Review of Indications and Outcomes of Unilateral Biportal Endoscopic Discectomy from the Current Literature

OBJECTIVE

Unilateral biportal endoscopic (UBE) spine surgery for spinal diseases has been increasing in popularity because of its favorable outcomes. The goal of this systemic review is to analyze the status of outcomes and complications in lumbar disc herniation during UBE discectomy.

METHODS

A comprehensive search of the PubMed, Embase, Web of Science, and OVID databases published until June 30, 2021, was performed. The outcomes of interest were indications, operative time, blood loss, hospital stay, complications, visual analog scale score, and Oswestry Disability Index.

RESULTS

Seven studies were included in our research. UBE surgery for lumbar stenosis was excluded. A total of 230 patients with lumbar disc herniation were enrolled in the 7 selected studies. The mean operative time was 74.4 minutes, and the mean length of hospital stay was 4.5 days. Mean incidence of complications reported in the 7 articles was 6.2%. UBE showed shorter hospital stays than did microdiscectomy, no significant differences of Oswestry Disability Index or visual analog scale scores, and good recovery rate among other discectomy techniques (microdiscectomy, full endoscopic transforaminal endoscopic lumbar discectomy, and interlaminar endoscopic lumbar discectomy) at 1 month follow-up.

CONCLUSIONS

Even with the small number of studies and reports analyzed, biases were the main limitation of this analysis; overall, the clinical outcomes and complication rates associated with UBE discectomy were relatively good. It is clear that UBE discectomy is a good treatment choice for lumbar disc herniation, but to prevent unique UBE surgery complications, a clear understanding of the surgical procedures and careful efforts to overcome the learning curve are necessary.

Comparison Between 3-Dimensional-Printed Titanium and Polyetheretherketone Cages: 1-Year Outcome After Minimally Invasive Transforaminal Interbody Fusion

OBJECTIVE

Three-dimensional (3D)-printed titanium implants have been developed recently, but the utility is not yet proven. The aim of this study was to compare 3D-printed titanium and polyetheretherketone (PEEK) implants after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

METHODS

Between October 2018 and September 2021, we retrospectively analyzed 83 patients who underwent single-level MIS-TLIF (3D-printed titanium, 40; PEEK, 43). Radiologic parameters were assessed with x-ray and computed tomography (CT) at postoperative 1 week, 6 months, and 1 year. Clinical status was evaluated using Oswestry Disability Index, visual analogue scale score, and Bridwell fusion grading was assessed on 6-month and 1-year postoperative CT.

RESULTS

There were no differences between the 2 groups in demographics and clinical outcomes. At 1-year of follow-up, the reported 3D-printed titanium fusion grades were grade I: 77.5% (31 patients), grade II: 17.5% (7 patients), and grade III: 5% (2 patients). The PEEK fusion grades were grade I: 51.2% (22 patients), grade II: 41.9% (18 patients), and grade III: 7.0% (3 patients). For overall fusion rate (grade I + II), there was no difference between the 2 cages (95.0% vs. 93.0%, p = 0.705), but grade I was reported at a higher incidence in 3D-printed titanium than PEEK (77.5% vs. 51.2%, p = 0.013). There was no difference between cages based on subsidence and complications.

CONCLUSION

There were no significant differences in the overall fusion rate for MIS-TLIF surgery between 3D-printed titanium and PEEK, but the fusion grade was better in 3D-printed titanium than in PEEK. Long-term follow-up is required to verify the effectiveness.

What does family involvement in care provision look like across hospital settings in Bangladesh, Indonesia, and South Korea?

BACKGROUND

Family members provide care whilst staying in the patient's room across a range of cultural settings, irrespective of resource availability in many Asian countries. This has been reported as a contributing factor to the spread of several outbreaks, including COVID-19. Despite these reports, very little is known about the risk of healthcare-associated infection (HAI) transmission related to the involvement of family and private carers in the clinical setting. As a starting point to understanding this issue, this study aimed to provide insights regarding the patient care activities undertaken by family and private carers and the guidance provided to these carers around infection control measures in hospitals located in Bangladesh, Indonesia, and South Korea.

METHOD

A qualitative study involving 57 semi-structured interviews was undertaken in five tertiary level hospitals across the selected countries. Two groups of individuals were interviewed: (1) patients and their family carers and private carers; and (2) healthcare workers, including doctors, nurses, hospital managers and staff members. Drawing upon the principles of grounded theory, an inductive approach to data analysis using thematic analysis was adopted.

RESULTS

Five main themes were generated from the analysis of the data: (1) expectation of family carers staying with a patient; (2) residing in the patient's environment: (3) caring activities undertaken by family carers; (4) supporting and educating family carers and (5) communication around healthcare-associated infection and infection prevention and control.

CONCLUSION

Based on the types of activities being undertaken, coupled with the length of time family and private carers are residing within the clinical setting, coupled with an apparent lack of guidance being given around IPC, more needs to be done to ensure that these carers are not being inadvertently exposed to HAI's or other occupational risks.

What Affects Segmental Lordosis of the Surgical Site after Minimally Invasive Transforaminal Lumbar Interbody Fusion?

PURPOSE

This study was undertaken to identify factors that affect segmental lordosis (SL) after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) by comparing patients whose postoperative SL increased with those whose decreased.

MATERIALS AND METHODS

Fifty-five patients underwent MIS-TLIF at our institute from January 2018 to September 2019. Demographic, pre- and postoperative radiologic, and cage-related factors were included. Statistical analyses were designed to compare patients whose SL increased with decreased after surgery.

RESULTS

After surgery, SL increased in 34 patients (group I) and decreased in 21 patients (group D). The index level, disc lordosis, SL, lumbar lordosis, proximal lordosis (PL), and Y-axis position of the cage (Yc) differed significantly between groups I and D. The cage in group I was more anterior than that in group D (Yc: 55.84% vs. 51.24%). Multivariate analysis showed that SL decreased more significantly after MIS-TLIF when the index level was L3/4 rather than L4/5 [odds ratio (OR): 0.46, p=0.019], as preoperative SL (OR: 0.82, p=0.037) or PL (OR: 0.68, p=0.028) increased, and as the cage became more posterior (OR: 1.10, p=0.032).

CONCLUSION

Changes in SL after MIS-TLIF appear to be associated with preoperative SL and PL, index level, and Yc. An index level at L4/5 instead of L3/4, smaller preoperative SL or PL, and an anterior position of the cage are likely to result in increased SL after MIS-TLIF.

Does Graft Position Affect Subsidence After Anterior Cervical Discectomy and Fusion?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Implant subsidence is an important prognostic factor after anterior cervical discectomy and fusion (ACDF). Our purpose in this study was to investigate whether graft position affects subsidence after ACDF and to determine if there is a difference in clinical results based on allograft subsidence and position.

METHODS

We reviewed 92 patients who underwent single-level ACDF with allograft and plate between January 2012 and October 2018. Treatment levels were divided based on allograft position within 2 mm of the posterior margin of the augmented plate (Anterior group) or at greater than 2 mm (Center group). Subsidence was defined as segmental vertebral body height decrease of 2 mm or more at 1 year compared to 1 week after surgery.

RESULTS

Overall subsidence prevalence was 15 (16%) cases. Subsidence was 11% in the Anterior group (8/73) and 39% in the Center group (7/19; P = .012). The subsidence group showed smaller graft footprint size (graft/endplate ratio) compared with the nonsubsidence group, and pseudarthrosis occurred frequently in the subsidence. There was no significant difference in clinical results according to graft position. These findings indicate that anterior graft position reduces risk of subsidence (95% confidence interval = 0.085-0.949).

CONCLUSION

To minimize risk of subsidence, the graft should be positioned on the anterior position of the surgical-level endplate. In addition, using a graft appropriate for endplate size will further reduce subsidence.

Clinical Experiences of 3-Dimensional Biportal Endoscopic Spine Surgery for Lumbar Degenerative Disease

BACKGROUND

The lack of stereoscopic vision in endoscopic spine surgery may lead to a risk of neural or vascular injury during endoscopic surgery. Three-dimensional (3D) endoscopy has not yet been attempted in the field of spinal endoscopic surgery.

OBJECTIVE

To present the technique, clinical efficacy, and safety of the 3D biportal endoscopic approach for the treatment of lumbar degenerative disease.

METHODS

We attempted 3D biportal endoscopic surgery for lumbar degenerative disease in a series of patients. Clinical outcomes and complications were evaluated postoperatively using a short questionnaire about 3D biportal endoscopic spine surgery that solicited respondents' opinions on the advantages and disadvantages of 3D biportal endoscopic surgery compared to the conventional 2D biportal endoscopic approach.

RESULTS

We performed 3D biportal endoscopic spine surgery in 38 patients with lumbar degenerative disease. Optimal neural decompression was revealed by postoperative magnetic resonance imaging in all enrolled patients. The 3D endoscopic vision clearly demonstrated the surgical anatomy starting with the exposure of ligamentum flavum, dura, and nerve root, and 3D endoscopy precisely depicted pathologic lesions such as bony osteophytes and ruptured disc herniation. There were no major complications including neural injury or durotomy.

CONCLUSION

The 3D endoscope may be able to distinguish between normal structures and lesions. The stereognosis and depth sensation of 3D biportal endoscopic spinal surgery might have a favorable impact on the safety of patients during endoscopic spine surgery.

Comparative Analyses of Clearing Efficacies of Tissue Clearing Protocols by Using a Punching Assisted Clarity Analysis

The advent of tissue clearing methods, in conjunction with novel high-resolution imaging techniques, has enabled the visualization of three-dimensional structures with unprecedented depth and detail. Although a variety of clearing protocols have been developed, little has been done to quantify their efficacies in a systematic, reproducible fashion. Here, we present two simple assays, Punching-Assisted Clarity Analysis (PACA)-Light and PACA-Glow, which use easily accessible spectroscopy and gel documentation systems to quantify the transparency of multiple cleared tissues simultaneously. We demonstrate the use of PACA-Light and PACA-Glow to compare twenty-eight tissue clearing protocols on rodent brains. We also show that regional differences exist in tissue transparency in the rodent brain, with cerebellar tissue consistently achieving lower clearing levels compared to the prefrontal or cerebral cortex across all protocols. This represents the largest comparative study of tissue clearing protocols to date, made possible by the high-throughput nature of our PACA platforms.

A novel paper MAP method for rapid high resolution histological analysis

Three-dimensional visualization of cellular and subcellular-structures in histological-tissues is essential for understanding the complexities of biological-phenomena, especially with regards structural and spatial relationships and pathologlical-diagnosis. Recent advancements in tissue-clearing technology, such as Magnified Analysis of Proteome (MAP), have significantly improved our ability to study biological-structures in three-dimensional space; however, their wide applicability to a variety of tissues is limited by long incubation-times and a need for advanced imaging-systems that are not readily available in most-laboratories. Here, we present optimized MAP-based method for paper-thin samples, Paper-MAP, which allow for rapid clearing and subsequent imaging of three-dimensional sections derived from various tissues using conventional confocal-microscopy. Paper-MAP successfully clear tissues within 1-day, compared to the original-MAP, without significant differences in achieved optical-transparency. As a proof-of-concept, we investigated the vasculature and neuronal-networks of a variety of human and rodent tissues processed via Paper-MAP, in both healthy and diseased contexts, including Alzheimer’s disease and glioma.

The potential cytotoxic effects of urban particle matter on olfaction

BACKGROUND

Urban particulate matter (UPM) in ambient air is implicated in a variety of human health issues worldwide, however, few studies exist on the effect of UPM on the olfactory system. This study aimed to identify the factors affecting the destruction of the olfactory system in a mouse model following UPM exposure.

METHODS

Mice were divided into: control and four UPM-exposed groups (200 µg UPM at 1 and 2 weeks, and 400 µg UPM at 1 and 2 weeks [standard reference material 1649b; average particle diameter 10.5 μm]). The olfactory neuroepithelium was harvested for histologic examination, gene ontology, quantitative real-time polymerase chain reaction, and western blotting.

RESULTS

Compared to the control group, olfactory marker protein, Olfr1507, ADCY3, and GNAL mRNA levels were lower, and S-100, CNPase, NGFRAP1, BDNF, and TACR3 mRNA levels were higher in the olfactory neuroepithelium of the UPM groups. Moderately positive correlation was present between the 1- and 2-week groups. After analyzing the 200 and 400 UPM groups separately, the strength of the association between the 200 UPM 1- and 2-week groups was moderately positive. No differences was present in the neuroepithelial inflammatory marker levels between the UPM and control groups.

CONCLUSIONS

UPM could have cytotoxic effects on the olfactory epithelium. The exposure time and particular concentration of UPM exposure could affect the degree of destruction of the olfactory neuroepithelium. The olfactory regeneration mechanism could be related to the neurotrophic factors, olfactory ensheathing cell stimulation, and trigeminal nerve support.

Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)

Objective

In this study, we investigate about relationship between postoperative global sagittal imbalance and occurrence of mechanical complications after adult spinal deformity (ASD) surgery. In global sagittal balance parameters, odontoid-hip axis (OD-HA) angle and T1 pelvic angle (TPA) were analyzed.

Methods

Between January 2009 and December 2016, 199 consecutive patients (26 males and 173 females) with ASD underwent corrective fusion of more than 4 levels and were followed up for more than 2 years. Immediate postoperative and postoperative 2 years whole spine x-rays were checked for evaluating immediate postoperative OD-HA, TPA, and other parameters. In clinical outcomes, back and leg pain visual analogue scale, Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), Oswestry Disability Index (ODI), 36-item Short Form Health Survey (SF-36) were evaluated.

Results

Based on the occurrence of mechanical complications, a comparative analysis was performed for each parameter. In univariable analysis, mechanical complications were significantly much more occurred in OD-HA abnormal group (odds ratio [OR], 3.296; p<0.001; area under the curve [AUC]=0.645). In multivariable analysis, the result was much more related (OR, 2.924; p=0.001; AUC=0.727). In contrast, there was no significant difference between normal and the occurrence of mechanical complications in TPA. In clinical outcomes (normal vs. abnormal), the differences of SRS-22 (0.88±0.73 vs. 0.68±0.64, p=0.042), ODI (-24.72±20.16 vs. -19.01±19.95, p=0.046), SF-36 physical composite score (19.33±18.55 vs. 12.90±16.73, p=0.011) were significantly improved in OD-HA normal group.

Conclusion

The goal of ASD surgery is to improve patient life quality through correction. In our study, TPA was associated with spinopelvic parameter and OD-HA angle was associated with health-related quality of life and complications. OD-HA angle is predictable factor for mechanical complications after ASD surgery.

Impact of COVID-19 on TB epidemiology in South Korea

SETTING: Five referral hospitals, South Korea.OBJECTIVE: To assess epidemiological changes in TB before and during the COVID-19 pandemic.DESIGN: This was a multicentre cohort study of 3,969 patients diagnosed with TB.RESULTS: We analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years, P < 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019; P = 0.005).CONCLUSIONS: The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.

A therapeutic intervention for Alzheimer's disease using ginsenoside Rg3: its role in M2 microglial activation and non-amyloidogenesis

Previously, we have reported that ginsenoside Rg3 has typical activities for neuroprotection and Aβ42 clearance by modulating microglia. In this study, we determined the pivotal role of ginsenoside Rg3 in microglia and neuronal cells. In human microglia, Rg3 and its stereoisomers significantly restored inflammatory M1 to normal M0 state and promoted M2 activation by up-regulating acute cytokines such as interleukin-10 and Arginase 1. Moreover, scavenger receptor type A (SRA) was significantly elevated in the presence of ginsenoside Rg3 and 20(S)-Rg3. This indicated that ginsenoside Rg3 could play a crucial role in Aβ uptake and clearance under activated M2 state. We also observed that soluble amyloid precursor protein-alpha (sAPPα) and ADAM10 levels were increased in APP swe-transfected Nuro-2a neuronal cells, whereas sAPPβ was not processed, suggesting that ginsenoside Rg3 was involved in non-amyloidogenic processing. In immunocytochemistry, SRA and a disintegrin and metalloproteinase 10 (desintegrin and metalloproteinase-containing protein 10, ADAM10) were coincidently upregulated in the presence of ginsenoside Rg3 and its stereoisomers compared to those in normal control. Taken together, these results suggested that ginsenoside Rg3 could boost acute activation of microglia, promote Aβ uptake, and elevate the sAPPα processing under activated M2 state. Although in vivo studies need to be performed, it is certain that ginsenoside Rg3 is highly involved in ameliorating the pathogenesis of neurodegeneration and can be a promising candidate for treating Alzheimer's disease as a new therapeutic intervention.

Incorporating New Technologies to Overcome the Limitations of Endoscopic Spine Surgery: Navigation, Robotics, and Visualization

Recently, spine surgery has gradually evolved from conventional open surgery to minimally invasive surgery, and endoscopic spine surgery (ESS) has become an important procedure in minimally invasive spine surgery. With improvements in the optics, spine endoscope, endoscopic burr, and irrigation pump, the indications of ESS are gradually widening from lumbar to cervical and thoracic spine. ESS was not only used previously for disc herniations that were contained without migration but is also used currently for highly migrated disc herniations and spinal stenosis; thus, the indications of ESS will be further expanded. Although ESS has certain advantages such as less soft tissue dissection and muscle trauma, reduced blood loss, less damage to the epidural blood supply and consequent less epidural fibrosis and scarring, reduced hospital stay, early functional recovery, and improvement of quality of life as well as better cosmesis, several obstacles remain for ESS to be widespread because it has a steep learning curve and surgical outcome is strongly dependent on the surgeon's skillfulness. A solid surgical technique requires reproducibility and ensured safety in addition to surgical outcomes. In this review article, how to improve ESS was investigated by grafting novel technologies such as navigation, robotics, and 3-dimensional and ultraresolution visualization.

Deep Learning Application in Spinal Implant Identification

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

To demonstrate the clinical usefulness of deep learning by identifying previous spinal implants through application of deep learning.

SUMMARY OF BACKGROUND DATA

Deep learning has recently been actively applied to medical images. However, despite many attempts to apply deep learning to medical images, the application has rarely been successful. We aimed to demonstrate the effectiveness and usefulness of deep learning in the medical field. The goal of this study was to demonstrate the clinical usefulness of deep learning by identifying previous spinal implants through application of deep learning.

METHODS

For deep learning algorithm development, radiographs were retrospectively obtained from clinical cases in which the patients had lumbar spine one-segment instrument surgery. A total of 2894 lumbar spine anteroposterior (AP: 1446 cases) and lateral (1448 cases) radiographs were collected. Labeling work was conducted for five different implants. We conducted experiments using three deep learning algorithms. The traditional deep neural network model built by coding the transfer learning algorithm, Google AutoML, and Apple Create ML. Recall (sensitivity) and precision (specificity) were measured after training.

RESULTS

Overall, each model performed well in identifying each pedicle screw implant. In conventional transfer learning, AP radiography showed 97.0% precision and 96.7% recall. Lateral radiography showed 98.7% precision and 98.2% recall. In Google AutoML, AP radiography showed 91.4% precision and 87.4% recall; lateral radiography showed 97.9% precision and 98.4% recall. In Apple Create ML, AP radiography showed 76.0% precision and 73.0% recall; lateral radiography showed 89.0% precision and 87.0% recall. In all deep learning algorithms, precision and recall were higher in lateral than in AP radiography.

CONCLUSION

The deep learning application is effective for spinal implant identification. This demonstrates that clinicians can use ML-based deep learning applications to improve clinical practice and patient care.Level of Evidence: 3.

Suppressed Degradation and Enhanced Performance of CsPbI3 Perovskite Quantum Dot Solar Cells via Engineering of Electron Transport Layers

CsPbI₃ perovskite quantum dots (CsPbI₃-PQDs) have recently come into focus as a light-harvesting material that can act as a platform through which to combine the material advantages of both perovskites and QDs. However, the low cubic-phase stability of CsPbI₃-PQDs in ambient conditions has been recognized as a factor that inhibits device stability. TiO₂ nanoparticles are the most regularly used materials as an electron transport layer (ETL) in CsPbI₃-PQD photovoltaics; however, we found that TiO₂ can facilitate the cubic-phase degradation of CsPbI₃-PQDs due to its vigorous photocatalytic activity. To address these issues, we have developed chloride-passivated SnO₂ QDs (Cl@SnO₂ QDs), which have low photocatalytic activity and few surface traps, to suppress the cubic-phase degradation of CsPbI₃-PQDs. Given these advantages, the CsPbI₃-PQD solar cells based on Cl@SnO₂ ETLs show significantly improved device operational stability (under conditions of 50% relative humidity and 1-sun illumination), compared to those based on TiO₂ ETLs. In addition, the Cl@SnO₂-based devices showed improved open circuit voltage and photocurrent density, resulting in enhanced power conversion efficiency (PCE) up to 14.5% compared to that of TiO₂-based control devices (PCE of 13.8%).

Influence of Frailty on Life Expectancy in Octogenarians After Lumbar Spine Surgery

Objective

Many studies have reported positive surgical outcomes and decreased mortality after spine surgery in the elderly population, including patients between 85 and 90 years of age. Here, in addition to patient age, we investigated the influence of frailty on short and long-term mortality in octogenarians after lumbar surgery.

Methods

We performed a retrospective analysis of 162 patients over 80 years of age who underwent posterior lumbar fusion or decompressive laminectomy between January 2011 and September 2016. We examined patient survival and modified frailty index (mFI) from medical records.

Results

By October 2019, 29 of 162 patients had expired (follow-up period: 1–105 months). Three-month mortality was 1.9%, and 1-year mortality was 4.9%. Frailty did not affect long-term survival at 1 year but was associated with 3-month mortality (p = 0.024).

Conclusion

There was no relationship in long-term survival according to frailty in patients 80 years of age or older, but a difference was identified in short-term mortality. When making a surgical decision for lumbar spine surgery in frail patients over 80 years of age, surgeons should pay attention to the short-term prognosis.

The Technical Feasibility of Unilateral Biportal Endoscopic Decompression for The Unpredicted Complication Following Minimally Invasive Transforaminal Lumbar Interbody Fusion: Case Report

Minimally invasive techniques for transforaminal lumbar interbody fusion (MIS-TLIF) are advantageous because they allow for sufficient surgical exposure and fewer complications through a smaller incision than conventional TLIF. It could be difficult to maintain minimally invasive spine surgery following the unexpected complications after MIS-TLIF. Because MIS-TLIF is usually done via a paramedian small incision with posterior fusion using screws and rods, visualization of the surgical field is limited, and it is difficult to directly assess the neural structure without removing instrumentation. Unilateral biportal endoscopic decompression (UBE) is a rapidly growing surgical method using two 1-cm incisions that are 2 to 3 cm apart. We would like to suggest UBE as an option for immediate reoperation after MIS-TLIF because it has the advantages of targeting pathologic regions and a wide field of visualization through small wounds. The operation is independent of the existing incision from MIS-TLIF, enabling immediate revision surgery without the removal of the screws and rods. UBE has the advantages of targeting specific surgical regions and providing a wide visualization of the operation field through small incisions. UBE can be very useful for discectomy or decompression surgery as well as in immediate reoperation after MIS-TLIF.

Surgical Outcomes of Dysphagia Provoked by Diffuse Idiopathic Skeletal Hyperostosis in the Cervical Spine

PURPOSE

This study aimed to predict the surgical outcomes of diffuse idiopathic skeletal hyperostosis (DISH)-related dysphagia (DISH-phagia) and to evaluate the importance of prevertebral soft tissue thickness (PVST).

MATERIALS AND METHODS

In total, 21 surgeries (anterior osteophytectomy or anterior cervical decompression and fixation) were included in this study for DISH-phagia from 2003 to 2019. Clinical outcomes were assessed using the Dysphagia Outcome and Severity Scale (DOSS) preoperatively, at 1 month postoperatively, and last follow up (mean 29.5 months). PVST was measured using lateral plain radiographs. Paired t-test and Spearman's correlation test was used to identify relationships between various PVST indices and DOSS.

RESULTS

Comparisons were made from 17 patients out of 21, in which the record had all of three measurements. The narrowest PVST preoperatively was 2.55±0.90 mm, with a DOSS score of 4.47±1.61, and that at 1 month after surgery was 5.02±2.33 mm, with a DOSS score of 6.12±1.32. At last follow up, PVST and DOSS values were 3.78±0.92 mm and 5.82±1.34, and three patients experienced symptom relapse. Significant relationships were found between PVST and DOSS at all time points: before surgery (R=0.702, p<0.001), 1 month after surgery (R=0.539, p=0.012), and last follow up (R=0.566, p=0.020).

CONCLUSION

Surgical removal of anterior osteophytes is an effective treatment option for DISH-phagia, and PVST is a useful parameter in DISH-phagia. The goal of DISH surgery should be to remove DISH as much as possible to ensure sufficient PVST postoperatively.

Akt1-Mediated Phosphorylation of RBP-Jk Controls Notch1 Signaling

The Notch1 signaling pathway plays a crucial role in determining cell fate, including cell growth and differentiation. In this study, we demonstrated that the antagonistic action of RTK (receptor tyrosine kinase) signaling pathway on the Notch1 signaling pathway is mediated via Ras-PI3K-Akt1. The PI3K-Akt1 signaling pathway was shown to inhibit Notch1 signaling via phosphorylation of RBP-Jk. We observed not only reduced association between Notch1 and RBP-Jk, but also suppression of the Notch1 transcriptional activity. Our results demonstrated that Akt1 functions as a natural inhibitor of the Notch1 signaling pathway via phosphorylation of RBP-Jk.

Biomarkers and new therapeutic targets in renal cell carcinoma

OBJECTIVE

Renal Cell Carcinoma (RCC) is the most common malignancy in adult kidneys. The American Cancer Society estimated 62,700 new cases and 14,240 deaths in 2018. Although early detection has improved in recent years, the treatment remains a challenge and reliable biomarkers for poor outcomes become necessary for the prevention of metastases and improve the quality of patients' life during and after treatment. Then, the current status of the search for new RCC biomarkers was discussed, as well as the latest discoveries in the RCC risk and metastatic treatment were discussed in this review.

MATERIALS AND METHODS

Extensive research was carried out in the online databases and full-free text articles published in the last 5 years, or more when convenient, were evaluated. Articles were included that addressed the proposed theme and were published in the English language.

RESULTS

The present state of knowledge on biomarkers for RCC carcinogenesis and progression is still much to be understood about RCC risk factors and molecular pathways resulting in metastatic progression. Newest RCC target therapies were discussed, mainly in relation to immunological therapy, and vaccines that have been tested in numerous trials with different cancer types.

CONCLUSIONS

The development of targeted therapies has revolutionized the treatment of advanced and metastatic cancers or non-responder patients. Combined therapy between classical chemotherapy and adjuvant immunotherapies has been modifying the cancer patients prognosis and bringing the hope of a cure in many cases.

Tunable broadband terahertz polarizer using graphene-metal hybrid metasurface

We demonstrate an electrically tunable polarizer for terahertz (THz) frequency electromagnetic waves formed from a hybrid graphene-metal metasurface. Broadband (>3 THz) polarization-dependent modulation of THz transmission is demonstrated as a function of the graphene conductivity for various wire grid geometries, each tuned by gating using an overlaid ion gel. We show a strong enhancement of modulation (up to ∼17 times) compared to graphene wire grids in the frequency range of 0.2-2.5 THz upon introduction of the metallic elements. Theoretical calculations, considering both plasmonic coupling and Drude absorption, are in good agreement with our experimental findings.

Comparison of open and pneumovesical approaches for Politano-Leadbetter ureteric reimplantation: a single-center long-term follow-up study

PURPOSE

To report our experience with the laparoscopic pneumovesical approach for Politano-Leadbetter ureteric reimplantation and to compare the results to those obtained using a traditional open approach.

METHODS

We retrospectively reviewed the medical records of 52 patients who underwent Politano-Leadbetter ureteral reimplantation between 2012 and 2017. The peri-operative parameters, postoperative outcomes, and complication rates of patients who underwent the open approach for the Politano-Leadbetter procedure and those who underwent the laparoscopic pneumovesical approach were compared.

RESULTS

During the study period, 52 ureteric reimplantation procedures were analyzed. Among these, 28 and 24 patients underwent surgery using the open and pneumovesical approaches, respectively. The mean operative time did not differ between the groups (143.64 min vs. 128.12 min, P = 0.092). However, the pneumovesical group had a shorter duration of hospital stay (5.08 days vs 7.43 days, P = 0.001) and required less morphine analgesic for pain than did the open group (7.7% vs 32.1%, P = 0.027). No significant differences in the success rates (94.9% vs 92.5%, P = 0.512) or procedure-related complications were noted between the pneumovesical and open techniques.

CONCLUSIONS

The transvesicoscopic Politano-Leadbetter technique with pneumovesicum is safe and effective for ureteric reimplantation and is comparable to the open approach.

Residence could influence the surgical outcome after corrective surgery in adult spinal deformity: comparison study between urban and rural area in Korea

PURPOSE

Numerous factors affect the surgical outcomes in patients with adult spinal deformity (ASD). However, no study has examined the relationship between residence and physical factors and surgical outcomes in patients with ASD. Here, we analysed the impact of residence and physical factors on the post-operative outcomes of patients with ASD residing in urban (U) and rural (R) environments.

METHODS

We retrospectively reviewed data from patients who had undergone ASD surgery with sacropelvic fixation at a single institution between June 2011 and May 2017 with a minimum 1 year follow-up. We divided the patients into two groups (U and R). Preoperative demographic data were reviewed, and radiographic parameters were measured preoperatively, immediately postoperatively, at 1, 3, and 6 months, and at the final follow-up. The L4 axial paraspinal muscles were measured preoperatively using magnetic resonance imaging.

RESULTS

There were 25 and 34 patients in the U and R groups, respectively. Both groups had similar preoperative demographic and radiological parameters. There were no differences between the groups in post-operative radiographic parameters, clinical outcomes, and complications, but proximal junctional kyphosis (PJK) was significantly higher in the R group. Additionally, muscle mass in the multifidus and erector spinae was lower in the R than in the U group.

CONCLUSIONS

Patient residence influenced PJK in patients with ASD. Mass reduction in the trunk extensor muscle is an important and existing risk factor for PJK. Surgeons should be aware of this information for preoperative counselling, informed consent, and post-operative education of patients with ASD. These slides can be retrieved from Electronic Supplementary Material.

Retrospective Study on Accuracy of Intraoperative Frozen Section Biopsy in Spinal Tumors

OBJECTIVE

Histologic types and grades are critical in the diagnosis and treatment of spinal tumors. Intraoperative frozen section is a fast and easy method in confirming pathologic diagnosis during the operation. This study was undertaken to reveal the accuracy of intraoperative frozen section biopsy in order to make proper treatment plans.

METHODS

This retrospective study concerned patients who underwent spinal tumor surgeries from 1 January, 2012 to 31 December, 2016. Frozen section biopsy and permanent biopsy were compared, and cases that had differences were counted.

RESULTS

Thirty-seven cases out of 324 patients had discrepancies (11.4%). In discrepant cases 11 cases were ependymoma (29.7%) and 6 cases were schwannoma (16.2%). Among 34 patients who were finally diagnosed with an ependymoma, 11 cases had discrepancies, which was the highest mismatch rate among tumor final pathologic types. By frozen biopsy, astrocytoma (n = 5) and ependymoma (n = 5) turned out to be the most discrepant pathologic types and 16 frozen section biopsy cases were "null." Frozen biopsy astrocytoma (n = 5) mostly turned out to be ependymoma in 4 cases.

CONCLUSIONS

Pathologic findings from frozen biopsy for spinal cord tumors could not be corresponded to final diagnosis, especially when the results of frozen biopsy were ependymoma or astrocytoma. Therefore careful decision making for treatment plans is required.

Abdominal compartment syndrome following posterior lumbar fusion in a patient with previous abdominal surgery

Introduction

Perioperative complications associated with spinal fusion have been investigated steadily to reduce morbidity and mortality. Although there are several reports reviewing abdominal complications occurring with anterior spinal fusion, complications related to posterior spinal fusion (PSF) are rare. However, abdominal compartment syndrome (ACS) after PSF could be the most fatal and unpredictable complication in spinal surgery.

Case presentation

This 73-year-old man with body mass index (BMI) of 23.02, and surgical history of appendectomy 10 years prior complained of severe nausea and vomiting on the second postoperative day of L4-5 transforaminal lumbar interbody fusion (TLIF). By postoperative day 4, he presented with dyspnea and fever, and the first diagnostic impression suggested aspiration pneumonia due to vomiting. Physical examination revealed severe abdominal distention and tenderness to palpation at most of the abdomen. Computed tomography (CT) scan of abdomen and chest revealed left inguinal hernia of the small bowel with incarceration suggesting intra-abdominal hypertension (IAH), and multifocal peri-bronchial consolidation in both lungs, respectively. His respiratory symptoms progressed to respiratory failure, and he was finally mechanically ventilated in conjunction with antibiotics. After 2 weeks of intensive care, the patient's symptom had improved, and finally he was transferred to a nursing facility.

Discussion

IAH and ACS rarely occur as abdominal complications of PSF. We suggest several risk factors including body mass index, abdominal surgical history, and long segment fusion for development of abdominal complications.

Reduction and monosegmental fusion for lumbar spondylolisthesis with a long tab percutaneous pedicle screw system: "swing" technique

OBJECTIVEWith the development of minimally invasive procedures, percutaneous pedicle screw systems have been used to attempt to correct spondylolisthesis. No previous studies have reported on reduction measures using long tab percutaneous pedicle screws for spondylolisthesis. Additional intraoperative correction has been proposed with the "swing" technique. This study was conducted to compare the efficacy of standard minimally invasive transforaminal interbody fusion (MIS-TLIF) with the efficacy of MIS-TLIF with the "swing" technique (MIS-TLIF and swing) in lumbar spondylolisthesis.METHODSThis was a matched-control study and included 30 consecutive patients who were followed up for 6 months after surgery. Of those patients, 15 were treated with operative reduction via MIS-TLIF with the "swing" technique, whereas the other 15 were treated with the standard MIS-TLIF procedure. The swing technique is a new reduction procedure for use with long tab percutaneous screws. In the swing technique, the entire system is swung back and forth several times after all constructs are placed. Only patients with Meyerding grade I or II lumbar spondylolisthesis were included in the study (18 with grade I and 12 with grade II). Perioperative and clinical outcomes, radiological parameters (Meyerding grade, percentage of slip, slip correction rate, segmental lordosis, and lumbar lordosis) were compared between groups at 6 months after surgery.RESULTSDemographic data did not differ significantly between the 2 groups. Postoperative clinical outcomes showed significant improvement in both groups. Postoperative radiological parameters showed that the degree of spondylolisthesis (swing: 4.7% vs standard: 8.9%) and reduction rate (swing: 77.3% vs standard: 57.1%) favored the swing group. The swing technique effectively decreased the degree of spondylolisthesis (swing: 24.1% to 4.7% vs standard: 21.8% to 8.9%). No complications related to the procedure were reported.CONCLUSIONSMIS-TLIF with the "swing" technique with long tab percutaneous pedicle screws is a safe and effective reduction method for monosegmental spondylolisthesis. This technique cannot only alleviate symptoms but also achieve nearly completely reduction of slippage.

Abstract P2-08-53: Tumor elasticity and clinicopathologic factors affecting neoadjuvant chemotherapy response in breast cancer patients

Background: Neoadjuvant chemotherapy for breast cancer has been increased. Many studies have reported on clinicopathologic factors to predict neoadjuvant chemotherapy response. Elastography, which is usually used to differentiate benign and malignant tumors, can be performed to evaluate tissue elasticity during conventional ultrasonography. The purpose of this study was to determine the clinicopathologic factors, including tumor elasticity, that affect neoadjuvant chemotherapy response in stage II or III breast cancer patients.

Methods: From April 2014 to March 2017, 95 patients received neoadjuvant chemotherapy for clinical stage IIa-IIIc primary breast cancer. To evaluate tumor elasticity, strain elastography was performed in 74 patients before neoadjuvant chemotherapy. Patients were divided into two groups by the Tsukuba elasticity scoring system (soft group ≤3 vs. hard group ≥4). Histologic type, nuclear grade, tumor infiltrating lymphocytes (TILs), tumor cellularity, characteristics of stroma, and hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status were evaluated using core needle biopsy specimens obtained before neoadjuvant chemotherapy. Pathologic complete response (pCR) was defined as the absence of invasive carcinoma in breast (ypT0 and ypTis) and axillary lymph node (ypN0). Residual cancer burden (RCB) was also calculated in 79 cases and the cases were categorized into 2 groups; favorable RCB group (RCB-0 and I) and unfavorable RCB group (RCB-II and III).

Results: The mean age of patients was 46.43±8.62 years (range, 27-71 years) and the mean initial tumor size was 3.63±1.95cm (range, 2.1-12.8cm). Twenty-four patients (32.4%) were categorized into the soft group and 50 patients (67.6%) into the hard group. The mean tumor cellularity on core needle biopsy specimens and characteristics of stroma were not significantly different between the two groups (p=0.35 and p=0.79, respectively). Twenty-two patients achieved pCR (23.2%). The patients with pCR were more likely to have estrogen receptor (ER) or progesterone receptor (PR) negative breast cancer (p=0.04 and p=0.03). The rate of nuclear grade 3 was higher in patients with pCR than those without (p=0.03). Tumor elasticity was not correlated with pCR (p=0.28). Thirty patients (38.0%) achieved favorable RCB and forty-nine patients (62.0%) had unfavorable RCB. Not only the rates of ER negativity (p=0.05), PR negativity (p=0.03), nuclear grade 3 (p=0.01), and high TILs level (≥ 10%) (p=0.04) but also the mean TILs level (p=0.05) were significantly higher in the favorable RCB group compared withthe unfavorable RCB group. No significant difference in tumor elasticity was observed between the two groups (p=0.30). In univariate analyses, nuclear grade 3 (p=0.03), and high TILs level (≥10%) (p=0.04) were significantly correlated with favorable RCB. HR negativity was an independent predictor of favorable RCB in multivariate analysis (odds ratio, 2.93; 95% confidence interval, 1.04-8.28; p=0.04).

Conclusion: Tumor elasticity was not associated with pCR or RCB. HR negativity was an independent predictor for favorable RCB.Nuclear grade and TILs were also potential predictive factors for neoadjuvant chemotherapy response.

Citation Format: Park JY, Choi JE, Bae YK, Lee SJ. Tumor elasticity and clinicopathologic factors affecting neoadjuvant chemotherapy response in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-53.

Abstract P6-09-09: Analysis of serial circulating tumor cell count during neoadjuvant systemic therapy in breast cancer patients

Background: We aimed to evaluate the clinical implication of circulating tumor cell (CTC) counts in correlation with prognosis and radiologic/pathologic response to therapy in locally advanced breast cancer patients undergoing preoperative systemic therapy.

Methods: From Feb 2014 to May 2017, 207 patients without distant metastasis were prospectively enrolled from AMC. CTC counts were analyzed before-during-after the therapy. CTC isolation was performed using a SMART BIOPSY™ SYSTEM Isolation kit (Cytogen, Inc., Seoul, Korea). Recurrence-free and overall survival was analyzed according to CTC counts.

Result: The mean follow-up period was 22.46 months and mean age was 46.48 years. One or more CTC was identified in 132 of 203 patients(65.0%) before NST, in 135 of 186 patients(72.0%) during NST and 103 of 171 patients(60.2%) after NST. Initial tumor burden at diagnosis -tumor size, lymph node metastasis- was not correlated with CTC positivity. Overall, CTC count ((≥1 CTC, ≥2 CTCs, and ≥5 CTCs) was not correlated with response to therapy. Using RECIST criteria, 86.5% (179/204) were responders (complete, partial response, CR/PR) and 12.1% (25/204) were non-responders (stable, progressive disease, SD/PD). 14.5% (30/207) showed a pathologic complete response (pCR), yet no association was found between CTC count/changes and radiologic/pathologic response to therapy. Also, CTC count was not correlated with prognosis among the whole population. However, HR+ tumors, CTC detection before NST was significantly associated with treatment response by RECIST criteria (responder vs. non-responder) (p=0.003, p=0.017 and p=0.023, respectively).

Conclusions: Our findings support limited value of CTC count for locally advanced breast cancers undergoing neoadjuvant systemic therapy.

Citation Format: Gwark S-C, Kim J, Kim YH, Kim MS, Park JY, Lee SB, Sohn G, Chung IY, Ko BS, Kim HJ, Lee JW, Son BH, Ahn SH. Analysis of serial circulating tumor cell count during neoadjuvant systemic therapy in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-09.

Evolution and persistence of resistance-associated substitutions of hepatitis C virus after direct-acting antiviral treatment failures

Daclatasvir plus asunaprevir (DCV+ASV) treatment is an all-oral direct-acting antiviral (DAA) therapy for the genotype 1b HCV-infected patients. In this study, we investigated how resistance-associated substitutions (RASs) evolved after treatment failures and assessed the effect of those substitutions on viral fitness. Sequencing of NS5A and NS3 revealed typical RASs after treatment failures. Interestingly, the RASs of NS3 reverted to the wild-type amino acid within 1 year after treatment failures. However, the RASs of NS5A were stable and did not change. The effect of NS5A and NS3 RASs on viral RNA replication was assessed after mutagenic substitution in the genotype 1b HCV RNA. Among single substitutions, the effect of D168V was more substantial than the others and the effect of the triple mutant combination (D168V+L31V+Y93H) was the most severe. The RAS at NS5A Y93 affected both viral RNA replication and virus production. Finally, the effect of trans-complementation of NS5A was demonstrated in our co-transfection experiments and these results suggest that such a trans-complementation effect of NS5A may help maintain the NS5A RASs for a long time even after cessation of the DAA treatment. In conclusion, the results from this investigation would help understand the emergence and persistence of RASs.

Enhanced sensitivity in THz plasmonic sensors with silver nanowires

We developed hybrid slot antenna structures for microbial sensing in the THz frequency range, where silver nanowires (AgNWs) were employed to increase the sensitivity. In order to fabricate the hybrid devices, we partially etched the AgNW in the slot antenna region, where we can expect the field enhancement effect at the AgNW tip. We measured the resonant-frequency shift observed upon the deposition of a polymer layer, and observed that the sensitivity increased upon the introduction of AgNWs, with an enhancement factor of more than four times (approximately six times in terms of figure-of-merit). The sensitivity increased with the AgNW density until saturation. In addition, we tested devices with PRD1 viruses, and obtained an enhancement factor of 3.4 for a slot antenna width of 3 μm. Furthermore, we performed finite-difference time-domain simulations, which confirmed the experimental results. The sensitivity enhancement factor decreased with the decrease of the slot width, consistent with the experimental findings. Two-dimensional mapping of the electric field confirmed the strong field localization and enhancement at the AgNW tips.

Does minimally invasive fusion technique influence surgical outcomes in isthmic spondylolisthesis?

OBJECTIVE

To compare the clinical and radiographic results between open transforaminal interbody fusion (TLIF-O) and minimally invasive TLIF (TLIF-M) for single-level low grade isthmic spondylolisthesis (IS).

METHODS

This study enrolled 45 patients who underwent single-level TLIF with low grade IS. The patients were divided into two groups according to operative method: TLIF-M (20 patients) and TLIF-O (25 patients). TLIF-O group was matched with TLIF-M.

RESULTS

At one-year postoperatively, there were no significant differences in any radiologic parameters between the two groups. Perioperative results such as blood loss, operation time, and hospital stay were superior in TLIF-M than in TLIF-O. Fusion was achieved in 17 of 20 patients (85.0%) in TLIF-M and 23 of 25 (92.0%) patients in TLIF-O. Back Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores of TLIF-O were significantly lower than TLIF-M at one (back VAS, ODI) and six months (ODI) postoperatively.

CONCLUSIONS

TLIF-M and TLIF-O produced similar clinical and radiological outcomes, including reduction of spondylolisthesis and disc space height restoration at one-year follow-up for single-level low grade IS. However, considering perioperative outcomes, back pain, and quality of life, TLIF-M might be a better option for single-level low grade IS compared to TLIF-O.

The timing of fusion surgery for clival chordoma with occipito-cervical joint instability: before or after tumor resection?

Clival chordoma with occipito-cervical (OC) joint invasion can result in preoperative and postoperative instability. The authors investigate the appropriate timing of OC fusion to prevent instability-, fusion-, and surgery time-related morbidity. Twenty-two consecutive patients underwent surgery for clival chordoma from December 2008 to September 2014. OC fusion was performed for patients with OC joint invasion and instability due to preoperative destruction of the occipital condyle or extensive postoperative condylectomy. The data in relation to OC joint instability, fusion, and surgery time were analyzed retrospectively and compared between OC fusion before and after tumor resection. Of the 22 patients, 8 with tumor invasion of the OC joint underwent OC fusion. OC fusion was performed after tumor resection in one-stage for four patients and before tumor resection in two-stage for four patients. There was OC joint instability from tumor destruction of the occipital condyle in seven patients (87.5%). Patients with OC fusion after tumor resection encountered complications such as surgery site wound dehiscence, encephalitis, and cardiac arrest with consequent mortality in one patient. These complications were avoided in subsequent patients where OC fusion was performed before tumor resection. There were no differences in the extent of tumor resection between OC fusion before and after tumor resection. Two-stage OC fusion before tumor resection can reduce instability-, fusion-, and surgery time-related morbidity and achieve feasible tumor resection when OC joint instability is expected. The extent of tumor invasion and brain stem compression should be considered when fusion precedes tumor resection.