Aachener Centrum für Technologietransfer in der Ophthalmologie

BACKGROUND: Oesophageal intraluminal impedance is currently used for assessment of reflux in gastro-oesophageal reflux disease (GORD). Oesophageal mucosa integrity may have a key role in heartburn perception in non-erosive reflux disease (NERD). Severe erosive oesophagitis is associated with low impedance baseline. We hypothesised that impedance baseline measurements could be used to evaluate changes in oesophageal mucosa integrity in man. METHODS: We measured oesophageal impedance baseline before, during and after acid perfusion in rabbits and healthy subjects. Transepithelial resistance (TER) was determined and dilated intercellular spaces (DIS) were assessed in isolated rabbit oesophageal mucosa. Impedance baseline was measured retrospectively at different levels of the oesophagus in impedance-pH recordings from asymptomatic volunteers and patients with GORD. RESULTS: In healthy subjects and rabbits, impedance baseline dropped dramatically during perfusion of control solution (pH 7.2) but after perfusion, impedance recovered. In rabbits, after perfusion with saline pH 1.5 and 1.0 impedance values remained a 39.1 ± 7.0% and 63.9 ± 6.5% (p < 0.05) lower respectively. There was a positive correlation between in vivo basal impedance and in vitro TER values (r = 0.72, p = 0.0021). Tissue showed no erosions but both acidic solutions induced DIS. In healthy subjects, after perfusion with saline pH 2.0 and 1.0 the impedance baseline remained lower a 21.9 ± 6.5% and 52.7 ± 5.0%, (p < 0.0001) respectively. Patients with GORD have a lower impedance baseline than healthy volunteers at the distal oesophagus. CONCLUSIONS: Impedance baseline measurements might be used to evaluate the status of the oesophageal mucosa and to study the role of the impaired mucosal integrity in acid-induced heartburn in healthy volunteers and in patients with GORD.

This paper investigates the topic of frame synchronization for systems based on the OFDM principle. After introducing the system model we discuss the task of a frame-synchronization and analyze the effects of a frame offset. From this we derive an appropriate criterion to measure the performance of synchronization algorithms under multipath conditions. We examine two algorithms for frame synchronization: the first algorithm is based on an evaluation of periodic structures. Since it is completely independent of a frequency offset it may be applied for system acquisition and burst synchronization. If the requirements are very high as in terrestrial TV broadcasting a second algorithm is needed to attain sufficient accuracy. The algorithm presented for this purpose is based on the evaluation of the channel estimate, so no further training data is required.

The prevalence of resistance to a range of antimicrobials was determined for isolates of Streptococcus pneumoniae examined in the PROTEKT (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin) surveillance study (1999-2000) using NCCLS testing methods and interpretative criteria. Of 3362 pneumococcal isolates collected from 69 centres in 25 countries, 22.1% overall were resistant to penicillin G, with the highest rates of resistance found among isolates from Asia (53.4%), France (46.2%) and Spain (42.1%). Erythromycin A resistance occurred in 31.1% of isolates overall with the highest rates found in Asia (79.6%), France (57.6%), Hungary (55.6%) and Italy (42.9%). Marked geographical differences in the prevalence of both penicillin G (the Netherlands 0%; South Korea 71.5%) and erythromycin A (Sweden 4.7%; South Korea 87.6%) resistance were observed. Asia was characterized by the highest prevalence of resistance, overall, with only eight of 19 antimicrobials (co-amoxiclav, linezolid, vancomycin, teicoplanin, quinupristin/dalfopristin, levofloxacin, moxifloxacin and telithromycin) retaining high activity against isolates of S. pneumoniae from this region. Notable rates of resistance to clarithromycin, azithromycin, co-trimoxazole and tetracycline were observed in the majority of countries submitting isolates of S. pneumoniae to the PROTEKT surveillance study. Fluoroquinolone resistance was low (1%), overall, although 14.3% of 70 isolates from Hong Kong were resistant to levofloxacin and moxifloxacin, all but one of these isolates belonging to a single clone of the 23F serotype. Although, at present, apparently limited to pockets of clonal spread, continued vigilance with regard to the evolution of fluoroquinolone resistance is indicated. Telithromycin (MIC(90) 0.12 mg/L; 99.9% of isolates susceptible) and lin- ezolid (MIC(90) 2 mg/L; 100% of isolates susceptible) were the two most active oral agents tested, both compounds retaining activity against isolates of fluoroquinolone-resistant S. pneumoniae. The results of the PROTEKT surveillance study 1999-2000 emphasize the widespread evolution of resistance to a variety of antimicrobials amongst isolates of S. pneumoniae and demonstrate the potential of telithromycin as a therapeutic option for the treatment of community-acquired respiratory tract infections caused by this organism.

Corneal transplantation is the treatment of choice for patients with advanced corneal diseases. However, the outcome may be affected by graft rejection, high associated costs, surgical expertise, and most importantly the worldwide donor shortage. In recent years, bioprinting has emerged as an alternative method for fabricating tissue equivalents using autologous cells with architecture resembling the native tissue. In this study, we propose a freeform and cell-friendly drop-on-demand bioprinting strategy for creating corneal stromal 3D models as suitable implants. Corneal stromal keratocytes (CSK) were bioprinted in collagen-based bioinks as 3D biomimetic models and the geometrical outcome as well as the functionality of the bioprinted specimens were evaluated after in vitro culture. We showed that our bioprinting method is feasible to fabricate translucent corneal stromal equivalents with optical properties similar to native corneal stromal tissue, as proved by optical coherence tomography. Moreover, the bioprinted CSK were viable after the bioprinting process and maintained their native keratocyte phenotypes after 7 days in in vitro culture, as shown by immunocytochemistry. The proposed bioprinted human 3D corneal models can potentially be used clinically for patients with corneal stromal diseases.

Germany's Textile Industry with its hybrid and highly fragmented value chains is seen as both a future key supplier and adopter of digital operations technologies and Industry 4.0 solutions. Yet, companies hesitate to start their digital transformation process due to severe implementation barriers including uncertainties about financial benefits and the lack of specialist knowledge. In order to overcome these challenges and to help textile manufacturersto kick-start their digital transformation, we are setting up the Textile Learning Factory 4.0 at the Institut für Textiltechnik der RWTH Aachen University in Aachen, Germany. The factory will become a central location to deliver capability building in a real-life demonstration and learning environment as well as a test base for piloting and scaling-up new digital solutions. Therefore, an end-to-end value chain from order to delivery for the manufacturing of smart, customer-specific textile products will be set up within the factory. The line will feature two development stages (Lean and Industry 4.0). In the Lean stage participants are going to learn how to systematically conduct a digital transformation while the Industry 4.0 stage will serve as a demonstrator featuring state-of-the-art digital solutions. In this paper, we want to present the initial motivation, the current status and the future prospects of the factory.

PURPOSE: The Ex Vivo Eye Irritation Test (EVEIT) is used to analyse the clinical observations of corneal calcification attributed to the presence of phosphate within applied eye-drops used in treating glaucoma, Still-Chauffard syndrome, ocular burns and dry eyes. METHOD: Live corneas from abattoir rabbit eyes were cultured in order to study epithelial healing following mechanical abrasion of the corneal surface combined with repeated exposure to various eye-drops. RESULTS: Obvious corneal calcification of the wound area along with a complete epithelial healing covering the calcified area was observed following exposure to phosphate hyaluronate eye-drops. Epithelial healing without calcification was achieved using citrate hyaluronate eye-drops. CONCLUSION: Clinical observations show that topical use of artificial tears containing phosphate on injured eyes may lead to sight-threatening corneal complications. Simulation of such treatment conditions by the EVEIT convincingly demonstrates that changes in the composition of the pharmaceutically used treatments can prevent this undesired side effect. Although considerable healing was achieved during the repeated application of eye-drops, using either a phosphate or citrate buffer, only the drops containing citrate did not develop corneal calcification on the eye. The authors therefore recommend discontinuing the use of phosphate-buffered eye-drops, or other topically applied solutions, to avoid further injury to the patient.

PURPOSE: To evaluate the impact of antiglaucoma drugs on the corneal healing process and corneal toxicity. MATERIALS AND METHODS: Four eye drops to treat glaucoma--Xalatan (latanoprost 50 μg/mL; Pfizer), Monoprost (latanoprost 50 μg/mL; Théa Pharma), Taflotan Sine (tafluprost 15 μg/mL; Santen Pharmaceutical Co.), Travatan (travoprost 40 μg/mL; Alcon), and 0.02% benzalkonium chloride (BAC) solution and HyloComod (1 mg/mL sodium hyaluronate; Ursapharm) as positive and negative control were tested regarding corneal irritability and effect on corneal healing. Formulas were tested over 3 days and administered 6 times daily on rabbit corneas cultured on an artificial anterior chamber (the Ex Vivo Eye Irritation Test system). Initially, 4 corneal abrasions (2.5 to 5.7 mm2) were applied. All defects were monitored during drug application by fluorescein stains and photographs. Glucose/lactate concentrations were monitored for corneal metabolic activity evaluation. RESULTS: For Xalatan and BAC, the corneal erosion size increased from 14.65 to 66.57 mm2 and 14.80 to 87.26 mm2. Travatan and Taflotan Sine did not interfere with corneal healing. Monoprost delayed corneal healing. For Xalatan and BAC, histology showed severe alteration of the superficial cornea. An increase in anterior chamber lactate concentration indicates corneal toxicity for Xalatan, BAC, and Monoprost. CONCLUSIONS: Corneal toxicity of Xalatan is most probably caused by BAC. Monoprost delays corneal healing, which is not well understood. The Monoprost effects could be caused by its additive, macrogolglycerolhydroxystearate 40. This excipient is a known skin irritant, and its concentration is relatively elevated in Monoprost, 50 mg/mL, compared with its active ingredient, latanoprost (0.05 mg/mL).

Abstract We have performed 2D and 3D gas hydrate (GH) petroleum systems modeling for the Pleistocene turbiditic sedimentary sequences distributed in the Daini-Atsumi area in the eastern Nankai Trough to understand the accumulation mechanisms and their spatial distribution related to geologic and geochemical processes. High-resolution seismic facies analysis and interpretations were used to define facies distributions in the models. We have created a new biogenic methane generation model based on the biomarker analysis using core samples and incorporated it into our model. Our 2D models were built and simulated to confirm the parameters to be used for 3D modeling. Global sea level changes and paleogeometry estimated from 3D structural restoration results were taken into account to determine the paleowater depth of the deposited sedimentary sequences. Pressure and temperature distributions were modeled because they are the basic factors that control the GH stability zone. Our 2D modeling results suggested that the setting of biogenic methane generation depth is one of the most important controlling factors for GH accumulation in the Nankai Trough, which may be related to the timing of methane upward migration (expulsion) and methane solution process in pore water. Our 3D modeling results suggested that the distribution of sandy sediments and the formation dip direction are important controlling factors in the accumulation of GHs. We also found that the simulated amount of GH accumulation from the petroleum systems modeling compares well with independent estimations using 3D seismic and well data. This suggests that the model constructed in this study is valid for this GH system evaluation and that this type of evaluation can be useful as a supplemental approach to resource assessment.

The use of high-resolution optical coherence tomography (OCT) to visualize penetration kinetics during the initial phase of chemical eye burns is evaluated. The changes in scattering properties and thickness of rabbit cornea ex vivo were monitored after topical application of different corrosives by time-resolved OCT imaging. Eye burn causes changes in the corneal microstructure due to chemical interaction or change in the hydration state as a result of osmotic imbalance. These changes compromise the corneal transparency. The associated increase in light scattering within the cornea is observed with high spatial and temporal resolution. Parameters affecting the severity of pathophysiological damage associated with chemical eye burns like diffusion velocity and depth of penetration are obtained. We demonstrate the potential of high-resolution OCT for the visualization and direct noninvasive measurement of specific interaction of chemicals with the eye. This work opens new horizons in clinical evaluation of chemical eye burns, eye irritation testing, and product testing for chemical and pharmacological products.

PURPOSE: Eye irrigation is a widely accepted therapeutic must in first aid treatment. The burning agent is removed, diluted, and if possible neutralized. Usually water, NaCl 0.9%, Ringer's lactate or phosphate buffer are the most accepted rinsing solutions. We present a relatively new substance called Previn (Diphoterine in countries other than Germany). It is a hypertonic, polyvalent, and amphoteric substance. Its binding energy for acids, bases, reducers, and oxidation is stronger than the binding energy of biological compounds for these burning agents. Concerning its compatibility with the eye and its efficacy, we compare Previn to the rinsing solutions in general use. MATERIAL AND METHODS: The first experiment (I) shows the effects of ocular rinsing with 500 ml Previn in ten healthy human subjects compared with phosphate buffer rinsing. Evaluation is done by slit lamp examination and confocal microscopy. An experimental study (II) compares in vitro buffering capacity (a) of Previn to other rinsing solutions and shows (b) in vivo efficacy of rinsing with Previn versus other rinsing solutions by pH measurements on the corneal surface and anterior chamber of rabbits after a 30-s burn with 1 N sodium hydroxide. RESULTS: (I) No harmful effect of irrigation with Previn could be found. Its compatibility with the eye is comparable to phosphate buffer rinsing. (II a) Buffering capacity was found to be stronger for Previn in acids and bases compared to phosphate buffer or Ringer's lactate. (II b) The in vivo study on rabbits proved Previn effect onaqueous pH comparable to phosphate buffer in buffering 1 N NaOH, whereas NaCl showed no buffering effect at all. CONCLUSION: The above studies have shown that Previn (Diphoterine) is comparable to other rinsing solutions concerning its compatibility with the human eye. Its buffering capacity is comparable to phosphate buffer. Previn and phosphate buffer should only be used in first aid treatment and not for continued rinsing therapy.

The problem of electromagnetic interference of electronic implants such as cardiac pacemakers has been well known for many years. An increasing number of field sources in everyday life and occupational environment leads unavoidably to an increased risk for patients with electronic implants. However, no obligatory national or international safety regulations exist for the protection of this patient group. The aim of this study is to find out the anatomical and physiological worst-case conditions for patients with an implanted pacemaker adjusted to unipolar sensing in external time-varying electric fields. The results of this study with 15 volunteers show that, in electric fields, variation of the interference voltage at the input of a cardiac pacemaker adds up to 200% only because of individual factors. These factors should be considered in human studies and in the setting of safety regulations.

PURPOSE: We assessed the accuracy of lens power calculation in highly myopic patients implanting plus and minus intraocular lenses (IOL). METHODS: We included 58 consecutive, myopic eyes with an axial length (AL) > 26.0 mm, undergoing phacoemulsification and IOL implantation following biometry using the IOLMaster 500. For lens power calculation, the Haigis formula was used in all cases. For comparison, refraction was back-calculated using the Barrett Universal II (Barrett), Holladay I, Hill-RBF (RBF) and SRK/T formulae. RESULTS: The mean axial length was 30.17 ± 2.67 mm. Barrett (80%), Haigis (87%) and RBF (82%) showed comparable numbers of IOLs within 1 diopter (D) of target refraction. Visual acuity (BSCVA) improved (p < 0.001) from 0.60 ± 0.35 to 0.29 ± 0.29 logMAR (> 28-days postsurgery). The median absolute error (MedAE) of Barrett 0.49 D, Haigis 0.38, RBF 0.44 and SRK/T 0.44 did not differ. The MedAE of Haigis was significantly smaller than Holladay (0.75 D; p = 0.01). All median postoperative refractive errors (MedRE) differed significantly with the exception of Haigis to SRK/T (p = 0.6): Barrett - 0.33 D, Haigis 0.25, Holladay 0.63, RBF 0.04 and SRK/T 0.13. Barrett, Haigis, Holladay and RBF showed a tendency for higher MedAEs in their minus compared to plus IOLs, which only reached significance for SRK/T (p = 0.001). Barrett (p < 0.001) and RBF (p = 0.04) showed myopic, SRK/T (p = 002) a hyperopic shift in their minus IOLs. CONCLUSIONS: In highly myopic patients, the accuracies of Barrett, Haigis and RBF were comparable with a tendency for higher MedAEs in minus IOLs. Barrett and RBF showed myopic, SRK/T a hyperopic shift in their minus IOLs.

Abstract Purpose This study analyzes the efficiency of different vitrectomy systems and compares single with double-bladed cutters. Methods The systems EVA™ (DORC), Constellation ® Vision System (ALCON), megaTRON S4 HPS (Geuder) and Stellaris ® PC (Bausch and Lomb) were used. We chose 20G and 23G probes, since not all systems had switched to a smaller G at the time the study was conducted in 2016. Cut rates were varied in increments of 1000 cuts/min from 500 cpm to the system’s maximum and vacuum pressures were varied in increments of 100 mmHg, from 100 to 600 mmHg up to the individual system’s maximum. In this study water, egg white, Pluronic ®− F127 gel and isolated porcine vitreous were used as models of human vitreous. The vitrectomy efficiency was calculated from the aspirated mass (g) within 30 s. The aperture of the different vitrectomy probes was filmed with a high-speed camera. Results The area under the curve analysis showed differences in efficiency between vitrectomy systems. For water, a reverse relationship between the aspirated mass and cut rate was shown. By contrast, for most systems aspirated egg white and porcine vitreous showed a non-linear increase or decrease for 4000 cpm and above. For all vitreous surrogates, EVA™’s double-bladed probe aspirated significantly (p &lt; 0.001) more vitreous than its mono-bladed probe. Video recordings showed less vitreous traction for double- in contrast to single-bladed probes. Conclusion We can demonstrate differences in the efficiency of vitrectomy depending on the vitrectomy system used. Double-bladed probes were more efficient and probably safer than single-bladed probes.

This paper deals with the long-term bonding and tensile strengths of textile reinforced mortar (TRM) exposed to harsh environments. The objective of this study was to investigate the long-term bonding and tensile strengths of carbon TRM by an accelerated aging method. Moisture, high temperature, and freezing-thaw cycles were considered to simulate harsh environmental conditions. Grid-type textiles were surface coated to improve the bond strength with the mortar matrix. A total of 130 TRM specimens for the bonding test were fabricated and conditioned for a prolonged time up to 180 days at varying moisture conditions and temperatures. The long-term bonding strength of TRM was evaluated by a series of bonding tests. On the other hand, a total of 96 TRM specimens were fabricated and conditioned at freezing-thaw conditions and elevated temperature. The long-term tensile strength of TRM was evaluated by a series of direct tensile tests. The results of the bonding test indicated that TRM was significantly degraded by moisture. On the other hand, the influence of the freezing-thaw conditions and high temperature on the tensile strength of the TRM was insignificant.

Abstract To examine the applicability of plasma-mediated vitreous body removal, a diode-pumped Q-switched Neodymium:YAG laser was used for a possible application in eye surgery/vitrectomy. On a total of 1500 porcine vitreous bodies, removal rates were evaluated by comparing different LaserVit-tip designs (Mark I/II Gauge 19 and Mark III Gauge 22). The Nd:YAG laser, operating at a wavelength of 1064 nm and a pulse duration of 4 ns, was utilized for vitreous body removal with respective settings of 2, 3 and 4 mJ and pulse repetition rates (cut rates) from 5 to 25 Hz (300–1500 /min) in 5 Hz-steps as well as for 100 Hz (6000 cuts/min). The exposure times were selected at 10, 20, 40 and 60 s, respectively. Comparative measurements were carried out with mechanical cutters (Gauge 20 and Gauge 23), applying a fixed cut rate of 800 /min (13.33 Hz) at identical exposure times. The LaserVit-tips showed successful vitreous body removal for all laser settings and exposure times (Mark I: 6.2 g/min, Mark II: 8.2 g/min at 1500 cuts/min and 3 mJ, Mark II: 10.1 g/min, Mark III: 3.6 g/min at 6000 cuts/min at 3 mJ). Similar tip-dimensions (Gauge 22 laser and Gauge 23 cutter ) showed comparable removal rates of 3.6 g/min laser and 1.3 g/min cutter with settings of 6000 cuts/min at 3 mJ (laser) and 800 cuts/min for the mechanical cutter. A diode-pumped Q-switched Nd:YAG laser can successfully and gently remove vitreous body. The efficiency of the laser was comparable to that of mechanical cutters in terms of quantity of material removed per time unit.

INTRODUCTION: Corneal epithelial toxicity and delayed healing process have already been attributed to preservatives or some excipients. We study the effects of galenic components in antiglaucoma drugs such as benzalkonium chloride (BAC) or surfactants like macrogolglycerol hydroxystearate 40 (MGHS 40) on corneal toxicity in an ex vivo system mimicking chronic use. METHODS: Latanoprost-containing eyedrops are available with and without preservatives on the market. Unpreserved, they are available in different formulations with various excipients like MGHS at different concentrations (0%, 2.5%, and 5%). We studied these in the ex vivo bioreactor (EVEIT) on initially injured rabbit corneas. The drugs were applied six times daily for observation periods of 3 or 5 days. BAC, 5% MGHS 40 solution, and 0.18% hyaluronic acid served as controls. Macroscopic photographic, biochemical methods and corneal integrity quantification were used for evaluation. Toxicity was assessed by measuring wound healing and corneal fluorescein sodium permeability and was confirmed by histology studies. RESULTS: The BAC-preserved formulation resulted in high corneal toxicity, which was expected. Interestingly, the preservative-free (PF) formulation containing 5% MGHS 40, carbomer, macrogol 4000, and sorbitol showed the highest corneal toxicity, followed by the control formulation with equal MGHS 40 concentration, which presented significantly less damage. No toxicity was shown by eyedrops containing 2.5% MGHS 40 or salts only. CONCLUSION: Our study demonstrates a significant corneal toxicity of certain formulations of PF antiglaucoma ophthalmic drugs containing 5% MGHS 40 with other excipients compared to other formulations with lower MGHS 40 concentrations (2.5% or 0%), or even compared to the solution containing 5% MGHS alone. This suggests a concentration-dependent toxicity of MGHS 40, especially in interaction with other excipients, which may increase its epithelial toxicity, and that has to be considered in clinical glaucoma therapy. Further single-component formulation trials are needed to support this interpretation.

Infectious diseases of the conjunctiva and cornea usually leave behind both broad local and systemic immunity. Case reports of SARS-CoV-2-positive conjunctivitis with subsequent systemic immunity suggest a new route of immunization preventing the primary infection of the airways. MATERIAL AND METHODS: = 8 hamsters served as controls (group 3). The weight development of the animals was recorded. After two weeks of observation of disease symptoms, all animals were re-exposed to SARS-CoV-2 in the respiratory tract (challenge) to determine whether immunity to the virus had been achieved. RESULTS: The epi-ocularly infected animals (group 1) showed no clinically visible disease during the ocular infection phase. At most, there was a slightly reduced weight gain compared to the control group (group 3), while the respiratory infected animals (group 2) all lost weight, became lethargic, and slowly recovered after two weeks. After the challenge, none of the animals in groups 1 and 2 became ill again. The animals in the negative control (group 3) all became ill. Cytotoxic antibodies were detectable in the blood of the infected groups before and after challenge, with higher titers in the epi-ocularly infected animals. CONCLUSION: By epi-ocular infection with SARS-CoV-2, the development of systemic immunity with formation of cytotoxic antibodies without severe general disease could be observed in the experimental animals, which did not induce any more disease upon a second infection in the respiratory tract. Therefore, it can be concluded that a purely epi-ocular infection with SARS-CoV2 only induces a weak disease pattern followed by systemic immunity.

Advancement in miniaturization of autonomous sensory agents can play a profound role in many applications such as the exploration of unknown environments, however, due to their miniature size, power limitations poses a severe challenge. In this paper, and inspired from biological instinctive behaviour, we introduce an instinct-driven dynamic hardware reconfiguration design scheme using evolutionary algorithms on behaviour trees. Moreover, this scheme is projected on an application scenario of autonomous sensory agents exploring an inaccessible dynamic environment. In this scenario, agent's compression behaviour -introduced as an instinct- is critical due to the limited energy available on the agents. This emphasises the role of optimization of agents resources through dynamic hardware reconfiguration. In that regard, the presented approach is demonstrated using two compression techniques: Zero-order hold and Wavelet compression. Behavioural and hardware-based power models of these techniques, integrated with behaviour trees (BT), are implemented to facilitate off-line learning of the optimum on-line behaviour, thus, facilitating dynamic reconfiguration of agents hardware.

INTRODUCTION: Potential advantages of the Extreme Lateral Interbody Fusion (XLIF) approach are smaller incisions, preserving anterior and posterior longitudinal ligaments, lower blood loss, shorter operative time, avoiding vascular and visceral complications, and shorter length of stay. We hypothesize that not every patient can be safely treated at the L4/5 level using the XLIF approach. The objective of this study was to radiographically (CT-scan) evaluate the accessibility of the L4/5 level using a lateral approach, considering defined safe working zones and taking into account the anatomy of the superior iliac crest. METHODS: Hundred CT examinations of 34 female and 66 male patients were retrospectively evaluated. Disc height, lower vertebral endplate (sagittal and transversal), and psoas muscle diameter were quantified. Accessibility to intervertebral space L4/5 was investigated by simulating instrumentation in the transverse and sagittal planes using defined safe zones. RESULTS: The endplate L5 in the frontal plane considering defined safe zones in the sagittal and transverse plane (Zone IV) could be reached in 85 patients from the right and in 83 from the left side. Through psoas split, the safe zone could be reached through psoas zone II in 82 patients from the right and 91 patients from the left side. Access through psoas zone III could be performed in 28 patients from the right and 32 patients from the left side. Safe access and sufficient instrumentation of L4/5 through an extreme lateral approach could be performed in 76 patients of patients from the right and 70 patients from the left side. CONCLUSION: XLIF is not possible and safe in every patient at the L4/5 level. The angle of access for instrumentation, access of the intervertebral disc space, and accessibility of the safe zone should be taken into account. Preoperative imaging planning is important to identify patients who are not suitable for this procedure.

OBJECTIVE: Families with one parent suffering from cancer are exposed to extraordinary emotional and organizational burdens, affecting underaged children. To help coordinated access to social and logistic support options and thus reduce the stress on family members, the project Brückenschlag was founded. The aim of this paper was to evaluate the implementation of this pilot project following the healthcare utilization model by Andersen. METHODS: A cross-sectional observational study was conducted using a mixed-method approach. Semi-structured written expert surveys (n=10) and secondary analysis of routine data of the care model (n=171 families) were combined. RESULTS: Quantitative secondary analysis: The participating families had 1-7 children (median (m) 2, range (s) 6). In 66% of the cases, the mother was affected by cancer, in 20% the diseased parent was in a single parent household. The communication structure in these families was rated "limited" to "rather open". Of the total of 171 contacts (study period 9/14 to 11/17), 133 families made use of Brückenschlag; 59.2% of the contacts were made by psycho-oncologists and the social services department of the hospital. If the contact was initiated by the patients themselves or by psycho-oncologists, a guidance was established significantly more frequently (significance of chi-squared test 0.047). Qualitative analysis: There was a lack of awareness and coordination of existing support services and a lack of family resources to use existing support offers. Both the desired and the established support fell primarily in the area of organizational support. Brückenschlag improved networking and took on a navigating function for the families. CONCLUSION: The data collected indicate that in families, matching the German average in their socio-demographic characteristics, a great need for organizational support develops as soon as one parent becomes sick with cancer. The model project Brückenschlag creates an access to support services for families with one parent suffering from cancer.