Contemporary innovations in two-dimensional transition metal dichalcogenide-based P-N junctions for optoelectronics.

Two-dimensional transition metal dichalcogenides (2D-TMDCs) with various physical characteristics have attracted significant interest from the scientific and industrial worlds in the years following Moore's law. The p-n junction is one of the earliest electrical components to be utilized in electronics and optoelectronics, and modern research on 2D materials has renewed interest in it. In this regard, device preparation and application have evolved substantially in this decade. 2D TMDCs provide unprecedented flexibility in the construction of innovative p-n junction device designs, which is not achievable with traditional bulk semiconductors. It has been investigated using 2D TMDCs for various junctions, including homojunctions, heterojunctions, P-I-N junctions, and broken gap junctions. To achieve high-performance p-n junctions, several issues still need to be resolved, such as developing 2D TMDCs of superior quality, raising the rectification ratio and quantum efficiency, and successfully separating the photogenerated electron-hole pairs, among other things. This review comprehensively details the various 2D-based p-n junction geometries investigated with an emphasis on 2D junctions. We investigated the 2D p-n junctions utilized in current rectifiers and photodetectors. To make a comparison of various devices easier, important optoelectronic and electronic features are presented. We thoroughly assessed the review's prospects and challenges for this emerging field of study. This study will serve as a roadmap for more real-world photodetection technology applications.

Recent advancement in quantum dot-based materials for energy storage applications: a review.

The need for energy storage and conversion is growing as a result of the worsening consequences of climate change and the depletion of fossil fuels. Energy conversion and storage requirements are rising as a result of environmental problems including global warming and the depletion of fossil fuels. The key to resolving the energy crisis is anticipated to be the quick growth of sustainable energy sources including solar energy, wind energy, and hydrogen energy. In this review, we have focused on discussing various quantum dots (QDs) and polymers or nanocomposites used for SCs and have provided examples of each type's performance. Effective QD use has really led to increased performance efficiency in SCs. The use of quantum dots in energy storage devices, batteries, and various quantum dots synthesis have all been emphasized in a number of great literature articles. In this review, we have homed in on the electrode materials based on quantum dots and their composites for storage and quantum dot based flexible devices that have been published up to this point.

Cation Incorporation and Synergistic Effects on the Characteristics of Sulfur-Doped Manganese Ferrites S@Mn(Fe2O4) Nanoparticles for Boosted Sunlight-Driven Photocatalysis.

In the present work, sulfur-doped manganese ferrites S@Mn(Fe2O4) nanoparticles were prepared by using the sol-gel and citrate method. The concentration of sulfur varied from 1 to 7% by adding Na2S. The samples were characterized by performing Fourier Transformed Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Ultraviolet-Visible spectroscopy (UV-Visible). The synthesized sulfur-doped manganese ferrites were applied to evaluate the photocatalytic degradation of the dyes. Further, the degradation studies revealed that the nanoparticles successfully degraded the methylene blue dye by adding a 0.006 g dose under the sunlight. The sulfur-doped manganese ferrite nanoparticles containing 3% sulfur completely degraded the dye in 2 h and 15 min in aqueous medium. Thus, the ferrite nanoparticles were found to be promising photocatalyst materials and could be employed for the degradation of other dyes in the future.

Eucalyptus Concoction Mediated Synthesis of Gold Nanoparticles and Its Bioactive Role Explored via Antimicrobial and Cytotoxic Studies.

Biosynthesis of nanoparticles has now become a novel trend in addressing some of the environmental issues by adopting eco-friendly approaches in manoeuvring nanoparticles for various applications. Plants and micro-organisms have been the potential sources of the biological mode of synthesizing nanoparticles as part of their bioremediation process. This principle has been harnessed for synthesizing nanoparticles either extra or intracellularly. In this line of phyto-mediated synthesis, eucalyptus buds have been used for synthesizing gold nanoparticles (Au NPs) under optimized laboratory conditions. The UV-visible spectrum of the Au NPs showed typical surface plasmon resonance at 550 nm (λmax) with a crystalline phase measuring <100 nm in size and monodispersed as revealed from XRD, FESEM, and AFM analyses. The biological role of phytochemical concoction in reducing and stabilizing the Au NPs was clearly identified from FT-IR studies. The antimicrobial effect of the Au NPs against clinically important pathogens viz. Staphylococcus sp., Pseudomonas sp., Bacillus sp. and E. coli determined using the disk diffusion method showed no significant antibacterial effect at all concentrations. Cytotoxicity studies were carried using Vero and HEp-2 cell lines and the 50% inhibition concentration (IC50) was determined to be 1.25 mg and 0.625 mg/mL respectively. Au NPs with potential antimicrobial and anti-proliferative effects could found profound implications in the field of nanomedicine once the toxicity in vivo has been investigated.

Visible-Light Driven Photocatalytic Degradation of Eosin Yellow (EY) Dye Based on NiO-WO3 Nanoparticles.

Herein, we report a simple synthesis, characterization and photocatalytic degradation application of composite NiO-WO3 nanoparticles. The nanoparticles were synthesized by facile low-temperature method and characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectra (DRS). The synthesized NiO-WO3 nanoparticles were used as efficient photocatalyst for the photocatalytic degradation of Eosin yellow (EY) dye. Interestingly, the synthesized photocatalytic exhibited a significant visible-light driven photocatalytic degradation of Eosin yellow (EY) dye. Under optimized conditions (pH = 5, catalyst dosage = 3 µM and initial dye concentration= 1.0 g/L), the obtained photo degradation of EY dye was above 95% in 180 min under visible light irradiation. Remarkably, reusability of the prepared photocatalyst was also observed and the photo-degradation reactions follow the pseudo-first-order model.

Synthesis of Iron Oxide@Pt Core-Shell Nanoparticles for Reductive Conversion of Cr(VI) to Cr(III) and Antibacterial Studies.

Herein, we report the facile synthesis of Iron oxide@Pt core-shell nanoparticles (NPs) by facile two step synthesis process. The first step follows the growth of iron oxide nanoparticle by thermal decomposition process while the second step deals with the formation of iron oxide@Pt core-shell nanoparticles by the chemical reduction method. The synthesized core-shell nanoparticles were characterized by several techniques and used for the catalytic reductive translation of Cr(VI) to Cr(III) in the presence of formic acid by a UV-vis spectrophotometer. The UV photo-spectrometer analysis confirmed the conversion efficiency from 12% to as high as 98.8% at the end of 30 minutes. Thus, the presence of Iron oxide @Pt core-shell nanoparticles (NPs) can be effectively used as a catalyst for the reducion of Cr(VI) to Cr(III) ions. Additionally, antibacterial studies were performed for the prepared core-shell nanoparticles against two bacterial strains, i.e., gram (+ve) Staphylococcus Aureus (S. Aureus) and gram (-ve) Escherichia Coli (E. Coli).

Effect of Nickel Doping on the Properties of Hydroxyapatite Nanoparticles.

Herein, we studied the effect of nickel (Ni) doping on the properties of hydroxyapatite (HAp) nanoparticles synthesized by facile ultrasonication assisted wet chemical synthesis process. Various doping concentrations of nickel, i.e., 0.01 M, 0.05 M and 0.10 M, were used to dope into hydroxyapatite nanoparticles. The synthesized nanoparticles were characterized by X-ray diffraction (XRD) pattern, scanning electron spectroscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, UV-Visible spectroscopy and Raman-scattering spectroscopy. The detailed structural characterizations confirmed that the crystallite sizes of the Ni-doped hydroxyapatite nanoparticles were reduced up to 53% compared to pure hydroxyapatite upon the doping of different concentrations of Ni ions. The agglomeration in the nanoparticles was also reduced by increasing the doping concentration of Ni ions. The XRD studies revealed that the average crystallite size of the synthesized Ni-doped HAp was decreased with increasing the concentration of Ni2+ ion doping and this observation was well-consistent with the SEM results. The FTIR and Raman studies well-confirmed the formation of pure HAp and Ni-doped HAp. Further, doping with Ni creates a new level of energy between the conductive band and the valence band and hence with increasing the concentration of Ni2+, the intensity in the UV-vis spectra was enhanced.

Sunlight-Driven Photocatalytic Degradation of Methyl Orange Based on Bismuth Ferrite (BiFeO3) Heterostructures Composed of Interconnected Nanosheets.

Herein, we report the facile microwave-assisted synthesis, characterization and photocatalytic degradation applications of Bismuth ferrite heterostructures composed of interconnected nanosheets (BHNs). The synthesized materials were subjected to several analytical studies such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and UV-visible spectroscopy in order to examine the morphological, structural, optical and photo catalytic properties. The structural and morphological characterizations confirmed the rhombohedral perovskite crystal structure and the formation of heterostructures composed of interconnected nanosheets for the synthesized material. The compositional characterization revealed that the synthesized material is bismuth ferrite with high purity. The BHNs were further used as efficient photocatalyst for the photocatalytic degradation of highly hazardous pollutant methyl orange under sunlight irradiation. The sunlight driven photocatalytic experiments revealed ~86% photodegradation of methyl orange dye in 150 min. The presented work revealed that the synthesized BHNs are excellent material for the photocatalytic degradation of various organic contaminants and hazardous pollutants.

Rapid Growth of TiO2 Nanoflowers via Low-Temperature Solution Process: Photovoltaic and Sensing Applications.

This paper reports the rapid synthesis, characterization, and photovoltaic and sensing applications of TiO2 nanoflowers prepared by a facile low-temperature solution process. The morphological characterizations clearly reveal the high-density growth of a three-dimensional flower-shaped structure composed of small petal-like rods. The detailed properties confirmed that the synthesized nanoflowers exhibited high crystallinity with anatase phase and possessed an energy bandgap of 3.2 eV. The synthesized TiO2 nanoflowers were utilized as photo-anode and electron-mediating materials to fabricate dye-sensitized solar cell (DSSC) and liquid nitroaniline sensor applications. The fabricated DSSC demonstrated a moderate conversion efficiency of ~3.64% with a maximum incident photon to current efficiency (IPCE) of ~41% at 540 nm. The fabricated liquid nitroaniline sensor demonstrated a good sensitivity of ~268.9 µA mM-1 cm-2 with a low detection limit of 1.05 mM in a short response time of 10 s.

Ginger and alpha lipoic acid ameliorate age-related ultrastructural changes in rat liver.

Because of the important role that oxidative stress is thought to play in the aging process, antioxidants could be candidates for preventing its related pathologies. We investigated the ameliorative effects of two antioxidant supplements, ginger and alpha lipoic acid (ALA), on hepatic ultrastructural alterations in old rats. Livers of young (4 months) and old (24 months) Wistar rats were studied using transmission electron microscopy. Livers of old rats showed sinusoidal collapse and congestion, endothelial thickening and defenestration, and inconsistent perisinusoidal extracellular matrix deposition. Aged hepatocytes were characterized by hypertrophy, cytoplasmic vacuolization and a significant increase in the volume densities of the nuclei, mitochondria and dense bodies. Lipofuscin accumulation and decreased microvilli in bile canaliculi and space of Disse also were observed. The adverse alterations were ameliorated significantly by both ginger and ALA supplementation; ALA was more effective than ginger. Ginger and ALA appear to be promising anti-aging agents based on their amelioration of ultrastructural alterations in livers of old rats.

A randomised controlled trial of coblation, diode laser and cold dissection in paediatric tonsillectomy.

OBJECTIVE: This study aimed to compare the efficacy of diode laser, coblation and cold dissection tonsillectomy in paediatric patients. METHODS: A total of 120 patients aged 10-15 years with recurrent tonsillitis were recruited. Participants were prospectively randomised to diode laser, coblation or cold dissection tonsillectomy. Operative time and blood loss were recorded. Pain was recorded on a Wong-Baker FACES(®) pain scale. RESULTS: The operative time (10 ± 0.99 minutes), blood loss (20 ± 0.85 ml) and pain were significantly lower with coblation tonsillectomy than with cold dissection tonsillectomy (20 ± 1.0 minutes and 30 ± 1.0 ml; p = 0.0001) and diode laser tonsillectomy (15 ± 0.83 minutes and 25 ± 0.83 ml; p = 0.0001). Diode laser tonsillectomy had a shorter operative time (p = 0.0001) and less blood loss (p = 0.001) compared with cold dissection tonsillectomy. However, at post-operative day seven, the diode laser tonsillectomy group had significantly higher pain scores compared with the cold dissection (p = 0.042) and coblation (p = 0.04) tonsillectomy groups. CONCLUSION: Both coblation and diode laser tonsillectomy are associated with significantly reduced blood loss and shorter operative times compared with cold dissection tonsillectomy. However, we advocate coblation tonsillectomy because of the lower post-operative pain scores compared with diode laser and cold dissection tonsillectomy.

Pilot comparison between potassium titanyl phosphate laser and bipolar radiofrequency in paediatric tonsillectomy.

OBJECTIVES: To compare the advantages and disadvantages of potassium titanyl phosphate laser with those of bipolar radiofrequency techniques, in paediatric tonsillectomy. STUDY DESIGN: Prospective, randomised, clinical study. PATIENTS AND METHODS: From July 2004 to April 2006, 80 patients aged between 10 and 15 years, with tonsillectomy planned for chronic tonsillitis, were included in the study. Children were prospectively randomised into two equal groups: potassium titanyl phosphate laser tonsillectomy and bipolar radiofrequency tonsillectomy. Operative time and intra-operative blood loss were recorded. Patients were scheduled for follow up during the first, second and fourth post-operative weeks. They were asked to record their pain and discomfort on a standardised visual analogue scale, from zero (no pain) to 10 (severe pain). Post-operative complications were also recorded and managed. RESULTS: The potassium titanyl phosphate laser group showed a slightly longer operative time (mean 12 minutes) than the bipolar radiofrequency group (mean 10 minutes). Intra-operative blood loss was significantly less in the potassium titanyl phosphate laser group (mean 21 cm3) than in the bipolar radiofrequency group (mean 30 cm3). In the first week, post-operative pain scores were less in the potassium titanyl phosphate laser group than in the bipolar radiofrequency group (means 7.5 and 8.5, respectively). However, in the second week pain scores increased more in the potassium titanyl phosphate laser group than in the bipolar radiofrequency group (means 8.5 and 6, respectively). In the fourth week, both groups showed equal and nearly normal pain scores. No case of reactionary post-tonsillectomy haemorrhage was recorded in either group. Only one case of secondary post-tonsillectomy haemorrhage was recorded, in the potassium titanyl phosphate laser group (2.5 per cent), managed conservatively. CONCLUSION: Both the potassium titanyl phosphate and the bipolar radiofrequency techniques were safe and easy to use for tonsillectomy, with reduced operative time, blood loss and complication rates and better post-operative general patient condition. Potassium titanyl phosphate laser resulted in reduced operative bleeding and immediate post-operative pain, compared with the bipolar radiofrequency technique. However, potassium titanyl phosphate laser required slightly more operative time and caused more late post-operative pain than the bipolar radiofrequency technique. The low rate of recorded complications showed that both techniques cause little damage to the tonsillar bed during dissection, thus minimising complications.

Long term clinical and echocardiographic results of mitral balloon valvotomy in children and adolescents.

AIMS: To assess the safety, efficacy, and long term results of mitral balloon valvotomy (MBV) for rheumatic mitral stenosis in children and adolescents in comparison to adults. METHODS: The results of 468 patients with mitral stenosis who underwent successful MBV and were followed up for 0.5-13 years were analysed. Patients were divided according to age at the time of MBV into group 1 consisting of 84 patients < or = 20 years of age (children and adolescents) and group 2 that included 384 patients, age > 20 (adults). RESULTS: Patients in group 1 had a lower mitral echo score (mean (SD) 7.5 (1.3) v 8 (1.1), p < 0.001), smaller Doppler mitral valve area (MVA) (0.84 (0.17) v 0.92 (0.18) cm2, p < 0.001), and higher Doppler mitral valve gradient (15.0 (5.3) v 12.7 (4.5) mm Hg, p < 0.001) than group 2. Immediately after MBV group 1 had larger MVA, whether measured by Doppler (2.0 (0.30) v 1.96 (0.28) cm2, p < 0.05) or by catheter (2.0 (0.59) v 1.8 (0.52) cm2, p < 0.001), and similar complication rates, compared to group 2. After a mean follow up of 5 (3.5) years there was no significant difference between groups 1 and 2 in the incidence of restenosis (14.3% v 16.1%, NS). Event-free survival rates at 5, 10, and 12.5 years were 93%, 79%, and 79% for group 1 and 94%, 90%, and 84% for group 2 (p = 0.18). CONCLUSIONS: MBV is safe and effective in children and adolescents with rheumatic mitral stenosis. It provides better immediate results than in adults and excellent long term results that are comparable to those seen in adults.

Neurilemmomas of the paranasal sinuses.

Within the head and neck region, neurilemmomas are rarely found in the nasal cavity or paranasal sinuses. A 70-year-old man presented with complaints of left-sided epiphora, rhinorrhea, epistaxis, and transient diplopia. Nasal endoscopy showed a large necrotic mass filling the left middle meatus. A computed tomography scan showed a large left ethmoid mass, with erosion of the medial wall of the orbit and the anterior cranial base. Multiple biopsies were nondiagnostic. Complete excision of the tumor was performed with endoscopic techniques. Small dural defects were repaired with a middle turbinate mucosal flap. Postoperatively, the patient was treated with nasal packing and a lumbar spinal drain. Final pathology showed a benign neurilemmoma. There has been no evidence of recurrence or cerebrospinal fluid leakage in follow-up. A review of the literature shows a similar presentation of patients with neurilemmomas of the paranasal sinuses. Bony destruction and intracranial extension is viewed. Lack of encapsulation and locally destructive growth in an otherwise histologically typical neurilemmoma should not suggest malignant potential. Many benign tumors of the paranasal sinuses with bone destruction may be removed by using endoscopic techniques.

Long-Term outcome of mitral balloon valvotomy in pregnant women.

BACKGROUND AND AIM OF THE STUDY: The study aim was to examine the long-term outcome (nine years) of mitral balloon valvotomy in pregnant patients with severe mitral stenosis. METHODS: Twenty-three patients with severe, symptomatic (NYHA class III/IV) mitral stenosis underwent mitral balloon valvotomy using an Inoue balloon technique during the second trimester of their pregnancy; mean follow up in 19 patients was 5.1 +/- 2.8 years (range: 1 to 9 years). RESULTS: The procedure was successful in all patients. Immediately after valvotomy, the Doppler-derived mitral valve area increased from 0.90 +/- 0.18 to 1.97 +/- 0.36 cm2 (p <0.0001), and the transmitral mean gradient decreased from 15.7 +/- 4.7 to 5.5 +/- 1.6 mmHg (p <0.0001). Four patients had mild worsening of mitral regurgitation, and six developed insignificant interatrial communication immediately after valvotomy. There was no other morbidity or mortality. Patients showed a significant improvement in mean NYHA class, from 3.0 +/- 0.1 to 1.0 +/- 0.02 (p <0.001). Twenty-two patients had normal deliveries; one cesarean section in week 36 resulted in stillbirth. No developmental abnormalities were seen in the babies. At long-term follow up of mothers, the mitral valve area was 1.8 +/- 0.52 cm2; restenosis developed in three patients (16%). One baby died at one week from sudden infant death syndrome, and one at eight months, from pneumonia. All other children showed normal growth, development and speech for their age. CONCLUSION: Mitral balloon valvotomy using the Inoue balloon technique can provide satisfactory immediate relief and long-term outcome in pregnant patients with severe mitral stenosis.

Long-term results of pulmonary balloon valvulotomy in adult patients.

BACKGROUND AND AIM OF THE STUDY: The study aim was to define the long-term outcome of pulmonary balloon valvulotomy (PBV) in adult patients. METHODS: PBV was performed in 87 patients (46 females, 41 males; mean age 23+/-9 years; range: 15-54 years) with congenital pulmonary valve stenosis (PS). Intermediate follow up catheterization (mean 14.6+/-5.0; range: 6-24 months) was performed after PBV in 53 patients. Clinical and Doppler echocardiography examinations were carried out annually in 82 patients (mean 8.0+/-3.9; range: 2-15 years). RESULTS: There were no immediate or late deaths. The mean catheter peak pulmonary gradient (PG) before and immediately after PBV, and at intermediate follow up was 105+/-39, 34+/-26 (p <0.0001) and 17+/-14 (p <0.0001) mmHg, respectively. The corresponding values for right ventricular (RV) pressure were 125+/-38, 59+/-21 (p <0.0001) and 42+/-12 (p <0.0001) mmHg, respectively. The infundibular gradients immediately after PBV and at intermediate follow up were 31+/-23 and 14+/-9 mmHg (p <0.0001), whilst cardiac index improved from 2.68+/-0.73 to 3.1+/-0.4 l/min/m2 (p <0.05) at intermediate follow up. Doppler PG before PBV and at intermediate and long-term follow up were 91+/-33 (range 36-200) mmHg, 28+/-12 (range 10-60) mmHg (p <0.0001) and 26+/-11 mmHg (p = 0.2), respectively. New pulmonary regurgitation (PR) was noted in 21 patients (25%) after PBV. Five patients (6%) with a suboptimal result (immediate valve gradient > or =30 mmHg) developed restenosis and underwent repeat valvulotomy 6-12 months later using a larger balloon, and with satisfactory outcome. Moderate to severe tricuspid regurgitation (TR) in seven patients regressed after PBV. CONCLUSION: The long-term results of PBV in adults are excellent, with regression of concomitant, severe infundibular stenosis and/or severe TR. Hence, PBV should be considered as the treatment of choice for adult patients with PS.

Retinal toxicity of triamcinolone acetonide in silicone-filled eyes.

OBJECTIVE: To determine the retinal toxicity of triamcinolone acetonide at different doses in vitrectomized, silicone-filled rabbit eyes. MATERIALS AND METHODS: Vitrectomy with silicone oil placement was performed in 32 rabbit eyes. A dosage of 1 mg/0.025 mL, 2 mg/0.05 mL, or 4 mg/0.1 mL of triamcinolone acetonide was injected intravitreally in the study group eyes; the control group received 0.1 mL of sterile saline. Electroretinography and retinal histology were performed to evaluate toxicity. RESULTS: No retinal toxicity was seen in the groups given 1, 2, and 4 mg of triamcinolone acetonide or in the control group. ERG and histologic sections in all groups were normal. No drug was visible in the vitreous cavity at the end of the 140-day period (average) in eyes injected with 4 mg of triamcinolone acetonide. CONCLUSIONS: Up to 4 mg of triamcinolone acetonide can be safely injected in silicone-filled, vitrectomized eyes without any significant retinal toxicity.

Endoscopic repair of cerebrospinal fluid leaks to the sinonasal tract: predictors of success.

INTRODUCTION: Cerebrospinal fluid (CSF) leaks may arise as a complication of endoscopic sinus surgery, trauma, or hydrocephalus, or they may occur spontaneously without any identifiable cause. Despite general agreement that CSF leaks should not be left untreated, their initial management, the surgical indications, and the technique of repair are controversial. OBJECTIVE: We undertook this study to ascertain whether a particular surgical technique or material was more successful for repair. Additionally, we tried to identify which specific characteristics of the patient, the CSF fistula, or the adjunctive treatment influenced the result of the repair. STUDY DESIGN: We completed a retrospective review of all patients undergoing endoscopic repair of a CSF leak at our academic hospitals. RESULTS: Forty-eight patients with 53 CSF fistulas were included in the study. Fifty sites were successfully repaired endoscopically on the first attempt. Three persistent leaks were repaired successfully on the second attempt. Location and size of the leak, cause, technique, and choice of material used for the repair did not significantly affect surgical outcome. However, the presence of hydrocephalus had a statistically significant negative influence on surgical outcome. All patients with increased intraventricular pressure required a ventricular shunt in addition to a second endoscopic repair. CONCLUSION: If the surgical technique is sound, endoscopic repair of CSF leaks is highly successful, independent of the choice of the material and technique used in the repair.

Transnasal endoscopic repair of cerebrospinal fluid rhinorrhea: a meta-analysis.

OBJECTIVES/HYPOTHESIS: Trauma and surgery are the most common causes of cerebrospinal fluid (CSF) rhinorrhea. Surgical repair is recommended for patients with CSF leaks that do not respond to conservative measures, traumatic CSF leaks that require transcranial surgery for associated brain injuries, and iatrogenic defects that are discovered intraoperatively. The purpose of our study was to ascertain the outcome after transnasal endoscopic repair of CSF leaks and to identify factors regarding the patient, CSF fistula, and treatment that may influence the results of the repair. METHODS: We performed a meta-analysis of all studies published in English between 1990 and 1999 that reported a minimum of five patients with CSF fistulae that were repaired using an endoscopic approach. We analyzed data that included type of graft and technique used during the repair, surgical complications, the use of packing, and the use of lumbar drains and antibiotics. The success rate was monitored and correlated with the other variables. The meta-analysis database was compared with and added to a database comprising our own patients. RESULTS: Fourteen studies comprising 289 CSF fistulae met the inclusion criteria. Endoscopic repair of CSF leaks was successful in 90% (259/289) of the cases after a first attempt. Seventeen of 30 persistent leaks (52%) were closed after a second attempt. Thus ultimately 97% (276/289) of the leaks were repaired using an endoscopic approach. The success rate of repairs using any of the reported techniques and materials was high and not statistically different. The incidence of major complications such a meningitis, subdural hematoma, and intracranial abscess was less than 1% for each complication. CONCLUSION: The endoscopic approach is highly effective and is associated with low morbidity. The literature supports the endoscopic approach using a variety of techniques and materials for the repair of CSF leaks.