Endoscopic anterior to psoas lumbar interbody fusion: indications, techniques, and clinical outcomes.

PURPOSE: The retrospective study aimed to report the surgical technique and clinic-radiological outcomes of endoscopic anterior to psoas interbody lumbar fusion through the retroperitoneal approach with direct and indirect decompression. METHODS: We retrospectively analyzed the results of clinical parameters of patients who underwent endoscopic anterior to psoas interbody lumbar fusion between June 2013 and June 2022. Clinical outcomes were evaluated by the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The radiological outcomes were measured and statistically compared in disc height index (DHI), whole lumbar lordosis (WLL), pelvic Incidence (PI), pelvic tilt (PT), Segmental lordosis (SL), the sagittal vertical axis (SVA). RESULTS: A total of 35 patients were selected for the procedure ranging in age from 51 to 84 years with 17.83 ± 8.85 months follow-up. The mean operation time in lateral position for one level was 162.96 ± 35.76 min (n = 24), and 207.73 ± 66.60 min for two-level fusion. The mean endoscopic time was 32.83 ± 17.71 min per level, with a total estimated blood loss of 230.57 ± 187.22 cc. The mean postoperative VAS back, leg pain score and ODI improved significantly compared to the preoperative values; Radiological data showed significant change in WLL, SL, DHI, PI, PT, and SS; however, there is no significant difference in SVA postoperatively. Subgroup analysis for the radiographic data showed 50 mm length cage has significantly improved for the DHI, SS and SVA compare to 40 mm length cage. The subgroup analysis results showed that hypertensive patients had significantly higher proportion in the incomplete fusion group compare to complete fusion group at one-year follow-up. OUTCOMES: The endoscopic anterior to psoas interbody lumbar fusion achieves satisfactory indirect and direct decompression. This convergent technique presents an effective choice for treating lumbar instability associated with disc herniations and foraminal stenosis, thus complementing the indications for oblique lumbar interbody fusion.

Computational Design of Crescent Shaped Promising Nonfullerene Acceptors with 1,4-Dihydro-2,3-quinoxalinedione Core and Different Electron-withdrawing Terminal Units for Photovoltaic Applications.

This study aims to design a series of nonfullerene acceptors (NFAs) for photovoltaic applications having 1,4-dihydro-2,3-quinoxalinedione fused thiophene derivative as the core unit and 1,1-dicyanomethylene-3-indanone (IC) derivatives and different π-conjugated molecules other than IC as terminal acceptor units. All the investigated NFAs are found air-stable as the computed highest occupied molecular orbitals (HOMOs) are below the air oxidation threshold (ca. -5.27 eV vs saturated calomel electrode). The studied NFAs can act as potential nonfullerene acceptor candidates as they are found to have sufficient open-circuit voltage (Voc) and fill factor (FF) ranging from 0.62 to 1.41 V and 83%-91%, respectively. From the anisotropic mobility analysis, it is noticed that the studied NFAs except dicyano-rhodanine terminal unit containing NFA, exhibit better electron mobility than the hole mobility, and therefore, they can be more promising electron transporting acceptor materials in the active layer of an organic photovoltaic cell. From the optical absorption analysis, it is noted that all the designed NFAs have the maximum absorption spectra ranging from 597 nm-730 nm, which lies in the visible region and near-infrared (IR) region of the solar spectrum. The computed light-harvesting efficiencies for the PM6 (thiophene derivative donor selected in our study):NFA blends are found to lie in the range of 0.96-0.99, which indicates efficient light-harvesting by the PM6:NFA blends during photovoltaic device operation.

The effect of the COVID-19 pandemic on hip fracture care: our experience at the University Hospitals of Leicester (UHL).

The United Kingdom (UK) Covid-19 pandemic has led to unique changes in the operation of the National Health Service (NHS) including within trauma and orthopaedics. This has led to a significant impact on the NHS ability to provide hip fracture care and sustain emergency surgery. This has led to local hip fracture services changing operations to provide more sustainable care and significant impacts on best practice tariffs. Data was collected using the National Hip Fracture Database data submitted by UHL and split into two cohorts - Pre Covid-19 and Post Covid-19. Data has been collected for 67 consecutive patients in April 2019 (Pre Covid-19) and 87 consecutive patients in April 2020 (Post Covid-19) as of 4th May after the introduction of the Covid-19 measures locally. Data has been collected on demographics- age and sex, ASA, admission time, time of operation, 30 day mortality and length of stay. The average time to theatre in the pre Covid-19 cohort was 27.3 hours and in the post Covid-19 cohort was 45.1 hours. This is an increase of 65.2%. All patients in the pre Covid-19 cohort were operated on and 4 in the post Covid-19 were conservatively managed. However, there were no significant effects on 30 day mortality or length of stay. In conclusion, the measures taken due to the Covid-19 pandemic had a profound impact on the care of hip fracture patients with significant delays in time to theatre. As a result, it is clear that the measures influenced practice at UHL and the best practice tariffs were not met.

The correlation of intraoperative distraction of intervertebral disc with the postoperative canal and foramen expansion following oblique lumbar interbody fusion.

PURPOSE: To examine the correlation of intraoperative distraction of intervertebral disc with the postoperative central canal and foramen expansion by oblique lumbar interbody fusion (OLIF) with indirect decompression. METHODS: Patients who underwent OLIF between October 2013 and April 2017 were included. Clinical outcomes included back and leg pain evaluated by visual analog scale (VAS) and Oswestry Disability Index (ODI). Intraoperative radiographic parameters of height ratio [(HR) = disc height/intervertebral body height)] and cage location were evaluated on intraoperative fluoroscopic images. Disc height (DH), foraminal height (FH), cross-sectional area of spinal canal (CSAC), and CSA of the foramen (CSAF) were measured. RESULTS: A total of 47 patients involving 62 levels were enrolled in this study. Mean follow-up was 43.8 ± 12.0 months. These patients reported an improvement of 61.7% in VAS back, 68.1% in VAS leg, and 46% in ODI (all p < 0.01). Radiographic parameters including HR, DH, FH, CSAC, and CSAF were also significantly increased by 32.6%, 48.2%, 21.4%, 44.0%, and 40.1% (left-side CSAF) or 45.4% (right-side CSAF), respectively (p < 0.05). HR increment was correlated with CSA (canal and foramen) increment. Slightly higher improvements of HR, DH, FH, CSAC, and CSAF (both sides) were noted when cage was located at middle rather than anterior (p > 0.05). CONCLUSIONS: The ligamentotaxis effect of OLIF is capable of supporting indirect decompression of central canal and neural foramina and clinical improvement. HR is a reliable intraoperative assessment method. In addition, intraoperative HR increment was correlated with postoperative neural elements expansion.

Infected Schmorl's node: a case report.

BACKGROUND: Schmorls node (SN) are mostly asymptomatic and incidental findings on MRI. However, sometimes they present like acute onset low back pain or acute exacerbation of chronic back pain after minor trauma. CASE PRESENTATION: We present rare case of symptomatic infected SN in 67 years female patient presented with complains of low back pain radiating to right buttock. After initial conservative treatment failed subsequent imaging showed significant increase in size of lesion with focal signal changes in disc space gave suspicion of underlying secondary pathology. Patient operated for complete excision of lesion. Histopathological report was suggestive of pyogenic vertebral osteomyelitis. Patient improved well postoperatively. CONCLUSION: Most of the time acute SN responds well to conservative treatment; however rapid deterioration of symptoms or persistent severe pain should give suspicion of underlying secondary pathology.

How I do it? Oblique lumbar interbody fusion at L5S1(OLIF51).

BACKGROUND: OLIF51 retains the advantages of traditional ALIF procedure with good fusion rates and improvement in radiographic parameters and reduces its drawbacks. It has the added advantage of being a minimal access technique. METHODS: Preoperative analysis of the vascular anatomy using CT angiography is mandatory. OLIF51 is done in right lateral position using specialized retractor blades and Thompson retractor system. The procedure is similar to OLIF at other levels except for the differences described here. The instruments are specialized for OLIF at L5S1. CONCLUSION: OLIF51 provides an excellent alternative to traditional ALIF.

How I do it? Transforaminal endoscopic decompression of intraspinal facet cyst.

BACKGROUND: Transforaminal endoscopic surgery provides equivalent results to open surgery with added advantages of feasibility under local anesthesia, no injury to posterior elements, preservation of the ligamentum flavum, ease of revision surgery, and cost-effectiveness. The technique of transforaminal endoscopic excision of cysts of facet or zygapophyseal joints is scarcely described in literature. METHODS: The transforaminal endoscopy is applicable to cyst lying in the extraforaminal, foraminal, and intraspinal regions. The "mobile" outside-in technique combined with osteotomy of the tip of the superior articular process facilitates intraspinal access for complete decompression. CONCLUSION: Transforaminal endoscopic removal of the facet cyst is a viable alternative to traditional open surgery with added advantages of a minimal access procedure.

α-Oligofurans: a computational study.

Recently, α-oligofurans have emerged as interesting and promising organic electronic materials that have certain advantages over α-oligothiophenes. In this work, α-oligofurans were studied computationally, and their properties were compared systematically with those of the corresponding oligothiophenes. Although the two materials share similar electronic structures, overall, this study revealed important differences between α-oligofurans and α-oligothiophenes. Twisting studies on oligofurans revealed them to be significantly more rigid than oligothiophenes in the ground state and first excited state. Neutral α-oligofurans have more quinoid character, higher frontier orbital energies, and higher HOMO-LUMO gaps than their α-oligothiophene counterparts. The theoretical results suggest that oligofurans (and subsequently polyfuran) have lower ionization potentials than the corresponding oligothiophenes (and polythiophene), which in turn predicts that oligofurans can be lightly doped more easily than oligothiophenes. Oligofuran dications (8 F(2+)-14 F(2+)) of medium-sized and longer chain lengths show a polaron-pair character, and the polycations of α-oligofurans cannot accommodate high positive charges as easily as their thiophene analogues.

Coordination-based molecular assemblies of oligofurans and oligothiophenes.

Molecular assemblies (MAs) of oligofurans and oligothiophenes were formed from solutions on various substrates. These films were obtained by alternating deposition of organic chromophores (oligofurans or oligothiophenes) and a palladium salt. These coordination-based MAs were characterized by UV/Vis spectroscopy, spectroscopic ellipsometry, atomic force microscopy (AFM), X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), and electrochemistry. The MAs exhibit similar electrochemical behavior and their growth and structure are apparently not affected when different organic template layers are used. The density of the MAs is a function of the structure of the molecular component. The oligothiophene density is approximately 50% higher than that observed for the oligofuran-based assemblies. The optical and electrochemical properties of the MAs scale linearly with their thickness. The UV/Vis data indicate that upon increasing the film thickness, there is no significant conjugation between the metal-separated organic chromophores. DFT calculations confirmed that the HOMO-LUMO gap of the surface-bound oligofuran and oligothiophene metal oligomers do not change significantly upon increasing their chain length. However, electrochemical measurements indicate that the susceptibility of the MAs towards oxidation is dependent on the number of chromophore units.

A 30-Year Worldwide Research Productivity of Scientific Publication in Full-Endoscopic Decompression Spine Surgery: Quantitative and Qualitative Analysis.

OBJECTIVE: The ever-growing number of articles related to full-endoscopic spine surgery published in the last few decades presents a challenge which is perplexing and time-consuming in identifying the current research status. The study aims to identify and analyze the most cited works related to full-endoscopic decompression spine surgery, compare the articles published by different publishers and area, and show the current publication status of full-endoscopic research. METHODS: Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science database between 1992 and 2022. Spine has the highest H-index with the most-cited journal in the field of full-endoscopic decompression spine surgery. China ranked as the most productive country, whereas the most cited with high H-index papers came from South Korea. For the author analysis, Yeung AT, Ruetten S, Hoogland T, Ahn Y, Choi G, and Mayer HM were the most impactful authors in the global and local citations. The most productive organization is Wooridul Spine Hospital. CONCLUSION: The bibliometric study showed a growing trend of research on full-endoscopic decompression spine surgery over the past 30 years. It has demonstrated that there is a significant increase in the number of authors, institutions, and internationally collaborated countries. However, the quality of studies is still low, and the lack of high-quality clinical evidence and the trend of general journal submissions has somewhat affected the quality of endoscopy journals in recent years.

Selenadiazolopyridine: a synthon for supramolecular assembly and complexes with metallophilic interactions.

The synthesis and characterization of the complexes of Cu(I), Ag(I), Cu(II), and Co(II) ions with 1,2,5-selenadiazolopyridine (psd) is reported. The following complexes have been prepared: [Cu(2)(psd)(3)(CH(3)CN)(2)](2+)2(PF(6)(-)); [(CuCl)(2)(psd)(3)]; [Cu(2)(psd)(6)](2+)2(ClO(4))(-); [Ag(2)(psd)(2)](2+)2(NO(3))(-); [Ag(2)(psd)(2)](2+)2(CF(3)COO)(-); [Cu(psd)(2)(H(2)O)(3)](2+)2(ClO(4))(-)·(psd)(2); [Cu(psd)(4)(H(2)O)](2+)2(ClO(4))(-)·(CHCl(3)); [Cu(psd)(2)(H(2)O)(3)](2+)2(NO(3))(-)·(H(2)O)·(psd)(2), and [Co(psd)(2)(H(2)O)(4)](2+)2(ClO(4))(-)·(psd)(2). The electronic structure of ligand psd, in particular the bond order of Se-N bonds, has been probed by X-ray diffraction, (77)Se NMR, and computational studies. A detailed analysis of the crystal structures of the ligand and the complexes revealed interesting supramolecular assembly. The assembly was further facilitated by the presence of neutral ligands for some complexes (Cu(II) and Co(II)). The molecular structure of the ligand showed that it was present as a dimer in the solid state where the monomers were linked by strong secondary bonding Se···N interactions. The crystal structures of Cu(I) and Ag(I) complexes revealed the dinuclear nature with characteristic metallophilic interactions [M···M] (M = Cu, Ag), while the Cu(II) and Co(II) complexes were mononuclear. The presence of M···M interactions has been further probed by Atoms in Molecules (AIM) calculations. The paramagnetic Cu(II) and Co(II) complexes have been characterized by UV-vis, ESI spectroscopy, and room temperature magnetic measurements.

Changes in Temperature Following Radiofrequency Thermal Ablation of the Nucleus Pulposus and Annulus Fibrosus: A Cadaveric Study.

BACKGROUND: Various minimally invasive procedures for treating discogenic pain have been reported in recent years. A Disc-FX® system can be used to perform nucleus pulposus (NP) removal, radiofrequency ablation, and annuloplasty under the guidance of x-ray fluoroscopy. However, when a probe tip with focused heat is placed on the intradiscal/subannular area to perform nucleo-annuloplasty using radiofrequency lesioning, thermal injury to the spinal cord or spinal nerves is a concern. OBJECTIVES: To assess the thermal profile generated by the Disc-FX ablation and modulation system in intervertebral discs from human cadaveric spine sections and evaluate the safety of its thermal dispersion function. STUDY DESIGN: A cadaveric study. METHODS: NP ablation and annulus fibrosus modulation were performed on a fresh human cadaveric lumbar spine intervertebral disc in a 36.5°C circulating water bath using radiofrequency. The 4 points from the center of the disc to one-third, two-thirds and the outer layer of the annulus were divided into 4 points, A-D, respectively, and radiofrequency lesions were performed on the 4 points. RESULTS: The temperature was increased upon irradiation. It fell slowly with the cessation of irradiation. The temperature was not significantly different between Turbo and Hemo mode at each point. The temperature was not significantly different among the 4 points at each mode. The average temperature of the ventral side of the dura mater was kept below 37°C. LIMITATIONS: The results of this study are limited due to the use of a cadaveric spine, which could not reflect the effect of soft tissue such as muscles and connective tissue around the disc. The position of the temperature measuring probe was relatively fixed. This cadaver demonstration was conducted at the L4-L5 level, which is mostly not restricted by the height of the iliac crest.  CONCLUSIONS: When performing NP ablation and annular modification, the epidural peripheral temperature should always be kept below 37°C. This preliminary in vitro research using human cadaveric discs showed that radiofrequency maintained the epidural space at a safe temperature during nucleo-annuloplasty.

Shedding light on triple-negative breast cancer with Trop2-targeted antibody-drug conjugates.

Triple-negative breast cancer (TNBC) is well-known as the most aggressive subtype of breast cancer. Because TNBC does not express Her2, estrogen receptor, and progesterone receptors, there had been no effective U.S. Food and Drug Administration-approved targeted therapy for it until PARP inhibitors and two PD-1/PD-L1 monoclonal antibodies were approved for treatment of TNBC. Most recently, an antibody-drug conjugate (ADC), called sacituzumab govitecan (SG), was approved for the treatment of TNBC patients previously received chemotherapy with advanced disease. SG consists of an anti-trophoblast cell-surface antigen 2 (Trop2) antibody conjugated with a topoisomerase I inhibitor, SN-38, which is diffused out of the targeted Trop2 positive cancer cells and induces the bystander killing effect on surrounding cells regardless of their Trop2 expression status. In the Phase III clinical trial, TNBC patients treated with SG showed significantly longer progression-free and overall survival compared to those who were received chemotherapy. In the present review, we summarized the cellular function and signaling of Trop2, the mechanism of action of SG, and the clinical trials of SG that led to its quick approval for TNBC. In addition, we introduced the current ongoing clinical trials of SG as well as another Trop2 ADC, which has potential to overcome some disadvantages of SG.

Superiority of MRI for Evaluation of Sacral Insufficiency Fracture.

STUDY DESIGN: Retrospective observational study. BACKGROUND: Sacral insufficiency fractures (SIF) are relatively rare fractures and difficult to diagnose on plain radiographs. The primary objective of the present study was to evaluate the role of lumbar magnetic resonance imaging (MRI) for the diagnosis of SIF. The secondary objective was to identify the classification of SIF by computed tomography (CT). METHODS: A total of 77 (Male 11, female 66, mean 80.3 years) people were included in this study. Inclusion criteria for this study were: age ≥ 60 years and no history of high energy trauma. Exclusion criteria were high energy trauma and a current history of malignancy. Differences in the fracture detection and description in the various radiologic procedures were evaluated. Fracture patterns were evaluated with CT. The detection rates of additional pathologies in the MRI of the pelvis and lumbar spine were also recorded. RESULTS: The sensitivities for SIF were 28.5% in radiographs and 94.2% in CT, and all fractures were detected in MRI. MRI showed a more complex fracture pattern compared with CT in 65% of the cases. We observed 71.4% of single SIFs, 9.1% with other spinal fractures, 13.0% with other pelvic fractures, and 7.8% with other fractures. According to the SIF fracture pattern, the H/U type was 40.2%, transverse type was 33.7%, λ/T type was 24.7%, unilateral vertical type was 1.3%, and bilateral vertical type was 0%. CONCLUSIONS: an MRI of the lumbar spine including the sacrum with a coronal fat-suppressed T2-weighted image is useful for elderly patients with suddenly increasing low back pain at an early stage. This procedure improves an early SIF detection, recognition of concomitant pathologies, and adequate treatment for the patients.

Trichoderma spp. Genes Involved in the Biocontrol Activity Against Rhizoctonia solani.

Rhizoctonia solani is a pathogen that causes considerable harm to plants worldwide. In the absence of hosts, R. solani survives in the soil by forming sclerotia, and management methods, such as cultivar breeding, crop rotations, and fungicide sprays, are insufficient and/or inefficient in controlling R. solani. One of the most challenging problems facing agriculture in the twenty-first century besides with the impact of global warming. Environmentally friendly techniques of crop production and improved agricultural practices are essential for long-term food security. Trichoderma spp. could serve as an excellent example of a model fungus to enhance crop productivity in a sustainable way. Among biocontrol mechanisms, mycoparasitism, competition, and antibiosis are the fundamental mechanisms by which Trichoderma spp. defend against R. solani, thereby preventing or obstructing its proliferation. Additionally, Trichoderma spp. induce a mixed induced systemic resistance (ISR) or systemic acquired resistance (SAR) in plants against R. solani, known as Trichoderma-ISR. Stimulation of every biocontrol mechanism involves Trichoderma spp. genes responsible for encoding secondary metabolites, siderophores, signaling molecules, enzymes for cell wall degradation, and plant growth regulators. Rhizoctonia solani biological control through genes of Trichoderma spp. is summarized in this paper. It also gives information on the Trichoderma-ISR in plants against R. solani. Nonetheless, fast-paced current research on Trichoderma spp. is required to properly utilize their true potential against diseases caused by R. solani.

2-Phenoxyethanol derived diselenide and related compounds; synthesis of a seven-membered seleninate ester.

Syntheses of several diorganodiselenides and, in particular, a seven-membered cyclic seleninate ester derived from 2-phenoxyethanol are described. The seleninate ester was obtained from allyl (2-(2-hydroxyethoxy)phenyl) selenide through a series of oxidation and [2,3] sigmatropic rearrangement steps. The ester exhibits good GPx-like activity in the coupled reductase assay.

The Evolution of Transforaminal Endoscopic Spine Surgery.

Transforaminal endoscopic spine surgery (T-ESS) has become a well-accepted technique. The first attempts at percutaneous discectomy by Kambin and Hijikata opened a new chapter of endoscopic spine surgery. By the last quarter of the twentieth century, spine surgeons had begun to adopt this novel technique. Many researchers helped advance endoscopic spine surgery, but the turning point was the description of a safe transforaminal triangle of safety by Parviz Kambin. Since then, the indications for T-ESS have increased as a result of the description of different surgical approaches such as inside-out, outside-in, and half-and-half. We present a review of crucial historical advancements in T-ESS and also discuss the evolution of endoscopes, the techniques used, development of endoscopic instruments and equipment, transforaminal thoracic endoscopy, transforaminal endoscopic interbody fusions, the growth of extended indications, and the future direction of T-ESS. This review provides a detailed description of key historical moments and a bird's-eye view of the vast scope of T-ESS.

Early results of full-endoscopic decompression of lumbar central canal stenosis by outside-in technique: A clinical and radiographic study.

ABSTRACT: Retrospective cohort study.Full-endoscopic decompression of lumbar spinal canal stenosis is being performed by endoscopic surgeons as an alternative to micro-lumbar decompression in the recent years. The outcomes of the procedure are reported by few authors only. The aim of this paper is to report the clinical and radiographic outcomes of full endoscopic lumbar decompression of central canal stenosis by outside-in technique at 1-year follow-up.We reviewed patients operated for lumbar central canal stenosis by full endoscopic decompression from May 2018 to November 2018. We analyzed the visual analogue scale scores for back and leg pain and Oswestry disability index at pre-op, post-op, and 1-year follow-up. At the same periods, we also evaluated disc height, segmental lordosis, whole lumbar lordosis on standing X-rays and canal cross sectional area at the affected level and at the adjacent levels on magnetic resonance imaging and the facet length and facet cross-sectional area on computed tomography scans. The degree of stenosis was judged by Schizas grading and the outcome at final follow-up was evaluated by MacNab criteria.We analyzed 32 patients with 43 levels (M:F = 14:18) with an average age of 63 (±11) years. The visual analogue scale back and leg improved from 5.4 (±1.3) and 7.8 (±2.3) to 1.6 (±0.5) and 1.4 (±1.2), respectively, and Oswestry disability index improved from 58.9 (±11.2) to 28 (±5.4) at 1-year follow-up. The average operative time per level was 50 (±16.2) minutes. The canal cross sectional area, on magnetic resonance imaging, improved from 85.78 mm2 (±28.45) to 150.5 mm2 (±38.66). The lumbar lordosis and segmental lordosis also improved significantly. The disc height was maintained in the postoperative period. All the radiographic improvements were maintained at 1-year follow-up. The MacNab criteria was excellent in 18 (56%), good in 11 (34%), and fair in 3 (9%) patients. None of the patients required conversion to open surgery or a revision surgery at follow-up. There was 1 patient with dural tear that was sealed with fibrin sealant patch endoscopically. There were 10 patients who had grade I stable listhesis preoperatively that did not progress at follow-up. No other complications like infection, hematoma formations etc. were observed in any patient.Full endoscopic outside-in decompression method is a safe and effective option for lumbar central canal stenosis with advantages of minimal invasive technique.

Enhancement of air-stability, π-stacking ability, and charge transport properties of fluoroalkyl side chain engineered n-type naphthalene tetracarboxylic diimide compounds.

In this study, the impact of fluoroalkyl side chain substitution on the air-stability, π-stacking ability, and charge transport properties of the versatile acceptor moiety naphthalene tetracarboxylic diimide (NDI) has been explored. A density functional theory (DFT) study has been carried out for a series of 24 compounds having different side chains (alkyl, fluoroalkyl) through the imide nitrogen position of NDI moiety. The fluoroalkyl side chain engineered NDI compounds have much deeper highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) than those of their alkyl substituted compounds due to the electron withdrawing nature of fluoroalkyl groups. The higher electron affinity (EA > 2.8 eV) and low-lying LUMO levels (<-4.00 eV) for fluoroalkyl substituted NDIs reveal that they may exhibit better air-stability with superior n-type character. The computed optical absorption spectra (∼386 nm) for all the investigated NDIs using time-dependent DFT (TD-DFT) lie in the ultra-violet (UV) region of the solar spectrum. In addition, the low value of the LOLIPOP (Localized Orbital Locator Integrated Pi Over Plane) index for fluoroalkyl side chain comprising NDI compounds indicates better π-π stacking ability. This is also in good agreement for the predicted π-π stacking interaction obtained from a molecular electrostatic potential energy surface (ESP) study. The π-π stacking is thought to be of cofacial interaction for the fluoroalkyl substituted compounds and herringbone interaction for the alkyl substituted compounds. The calculated results shed light on why side chain engineering with fluoroalkyl groups can effectively lead to better air-stability, π-stacking ability and improved charge transport properties.

Biportal Endoscopic Excision of Facetal Cyst in the Far Lateral Region of L5S1: 2-Dimensional Operative Video.

Unilateral biportal endoscopy (UBE) is a recently introduced technique that utilizes 2 portals, one for endoscopy and one as a working portal, in contrast to full endoscopy, which utilizes a single portal. The advantages are a favorable learning curve and free mobility of instruments in the operative field. UBE is successful in addressing cervical and lumbar disc herniations, lumbar stenosis, and foraminal/extraforaminal pathologies, such as herniations and foraminal stenosis. However, there is no report of UBE for a far-lateral L5S1 facet cyst. The patient was an 85-yr-old female with a left lower limb radicular pain with magnetic resonance imaging evidence of the facet cyst compressing the L5 nerve root. Conventional treatment of such a condition would either be an L5S1 fusion procedure or a standalone decompression via the Wiltse paramedian approach. Because the patient had no instability, we decided to do a standalone decompression using the UBE technique. The UBE technique has the advantages of any minimal access procedure, including small incisions, minimal tissue dissection, good magnification, and preservation of anatomic structures. A written informed consent was obtained from the patient before the procedure. The procedure was done under general anesthesia using a 30° endoscope, a radiofrequency probe, and standard lumbar spine surgery instruments. The initial landing point of the endoscope and instruments is via triangulation at the lateral border of the isthmus of L5. The postoperative clinical and radiological outcomes were satisfactory (VAS Back and Leg, 0; Oswestry disability index, 15 at 3 mo).