Gerald Langmann

Surgical smoke management for minimally invasive (micro)endoscopy: an experimental study

BackgroundThe aim of this study was to investigate the use of surgical smoke-producing procedures such as laser ablation or electrosurgery in minimally invasive microendoscopic procedures. This study proposes a technical solution to efficiently remove surgical smoke from very small endoscopic cavities using microports as small as 20 G (0.9xa0mm) in diameter.MethodsThe experimental laboratory study used small, rigid, transparent plastic cavity models connected with tubes and pressure sensors to establish an endoscopic in vitro laboratory model. A Kalium-Titanyl-Phosphate (KTP) laser with a 0.5-mm fiber optic probe was used to produce smoke from bovine scleral tissue in the cavity. Endoscopic gas insufflation into the model was generated by pressurized air and a microvalve. A laboratory vacuum pump provided smoke and gas suction via a microvalve. A self-built control and steering system was utilized to control intracavital pressure during experimental insufflation and suction.ResultsProblems related to smoke-generating processes, such as laser vaporization or electrocautery, in small closed cavities were first analyzed. A theoretical and mechatronic laboratory model was established and tested. Intracavital pressure and gas flow were measured first without and then with smoke generation. A new construction design for the suction tube was proposed due to rapid obstruction by smoke particles.ConclusionsSurgical smoke evacuation from endoscopic cavities that are as small as 2xa0cm in diameter via minimally invasive ports as small as 20 G (0.9xa0mm) in diameter may be safe and efficient if sufficient gas exchange is provided during smoke generation by laser or electrosurgical instruments. However, maintaining a low and constant pressure in the cavity during gas exchange and adopting a special construction design for the suction tube are essential to provide an excellent view during the surgical maneuver and to minimize potential toxic side effects of the smoke.

Ozurdex® reduces the retinal thickness in radiation maculopathy refractory to bevacizumab

pathognomonic for classic WD. He was diagnosed with kidney sarcoidosis before the WD diagnosis and was pharmacologically immunosuppressed. After the patient had his first cataract surgery performed, a severe mostly posterior uveitis was diagnosed. It did not respond to neither topical nor systemic immunosuppressive treatment. Case reports have described uveitis after intraocular operations in patients unknown to have WD, only diagnosed later on by vitreous samples. It is uncertain whether it is the operation in itself or the use of post-operative topical steroids that provokes the development of uveitis in these WD patients (Drancourt et al. 2009). In parallel with the eye problems, the patient developed significant neurological symptoms indicating involvement of the brain. WD is a fascinating disease entity with a wide range of clinical manifestations and has been considered to be an extremely rare disease (Raoult et al. 2000). This makes it difficult for clinicians to identify cases, especially the non-classic cases, with more atypical symptoms and findings. New data indicate that Tropheryma whipplei is ubiquitous in the environment (Maiwald et al. 1998). Clinicians treating patients with diffuse symptoms involving the brain and the eyes should not forget about this very rare disease which can be treated effectively with antibiotics.

Impact of dose rate on clinical course in uveal melanoma after brachytherapy with ruthenium-106.

Background and Purpose:It has been suggested that the actual dose rate of an irradiating source may be a distinct influencing factor for the biological effect after brachytherapy with ruthenium-106 for uveal melanoma. The purpose of this study was to investigate a hypothesized impact of the dose rate on the clinical and echographic course after brachytherapy.Patients and Methods:In total, 45 patients were included in this retrospective study. According to the actual dose rate, two groups were defined: group 1 with a dose rate < 4 Gy/h and group 2 with a dose rate ≥ 4 Gy/h. Regarding age, tumor height, basal diameter, scleral and apical dose, differences between the groups were not significant. Clinical parameters, including early and late side effects, and echographic courses were compared.Results:A significantly lower metastatic rate was found in group 2. Using univariate Cox proportional hazards regression, only dose rate predicted metastatic spread significantly (p < 0.05), while in a multivariate analysis, using age at the time of treatment, greatest tumor height and greatest basal diameter as covariates, the variable dose rate was of borderline significance (p = 0.077). Patients in group 2 had more early side effects and more pronounced visual decline, but these differences were of borderline significance with p-values of 0.072 and 0.064, respectively.Conclusion:These data suggest that a higher dose rate may confer a lower risk for metastatic spread, but may be associated with more side effects and more pronounced visual decline.Hintergrund und Ziel:Es wurde vermutet, dass die Dosisrate einer Strahlenquelle einen maßgeblichen Faktor für den biologischen Effekt nach Brachytherapie mit Ruthenium-106 beim uvealen Melanom darstellt. Ziel dieser Studie war die Untersuchung des Einflusses der Dosisrate auf den klinischen und echographischen Verlauf nach Brachytherapie.Patienten und Methodik:Insgesamt wurden 45 Patienten in diese retrospektive Studie eingeschlossen. Entsprechend der Dosisrate zum Zeitpunkt der Brachytherapie wurden zwei Gruppen definiert: Gruppe 1 mit einer Dosisrate < 4 Gy/h und Gruppe 2 mit einer Dosisrate ≥ 4 Gy/h. Bezüglich des Alters, der Tumorhöhe, des basalen Durchmessers sowie der Sklerakontakt- und apikalen Dosis bestand kein signifikanter Unterschied zwischen den beiden Gruppen. Klinische Parameter inklusive früher und später Nebenwirkungen sowie der echographische Verlauf wurden verglichen.Ergebnisse:Es fand sich eine signifikant niedrigere Metastasierungsrate in Gruppe 2. Mit der univariaten Cox-Regression zeigte sich nur für die Dosisrate ein signifikanter Zusammenhang (p < 0,05), während der Zusammenhang in der multivariaten Analyse mit Alter, größter Tumorhöhe und größtem Tumordurchmesser als Kovariablen grenzwertig war (p = 0,077). Patienten der Gruppe 2 hatten eine höhere Rate an frühen Nebenwirkungen und einen größeren Visusverlust, wobei die Unterschiede grenzwertig signifikant waren (p = 0,072 bzw. p = 0,064).Schlussfolgerung:Diese Daten lassen vermuten, dass eine höhere Dosisrate ein niedrigeres Metastasierungsrisiko aufweist, aber mit einer höheren Rate an Nebenwirkungen und größerem Visusverlust assoziiert ist.

Influence of single-fraction Gamma-Knife radiosurgery on ocular surface and tear function in choroidal melanoma patients

Aim To evaluate ocular surface and tear function in patients with choroidal melanoma treated with single-fraction radiosurgery. Methods 36 patients (median age 62u2005years; range 26–84u2005years) were enrolled between 2001 and 2006 at a single institution. They were treated with the Leksell Gamma Knife in one fraction with a median dose of 30u2005Gy (range 25–35u2005Gy). In both eyes of all patients treated subjective symptom score (visual analogue scale) was evaluated, central corneal sensitivity testing, Schirmer test without local anaesthesia, and corneal and conjunctival staining were performed before therapy and 3, 6, 12, 24 and 36u2005months thereafter. The respective untreated fellow eye served as control. Results Three months after radiosurgery, the subjective dry eye symptom score and lissamine green staining score of the ocular surface were significantly higher in the treated eyes compared with the fellow eyes (p<0.001, p=0.028, respectively). After 12u2005months, a significant difference between the treated and the fellow eyes in corneal sensitivity (p=0.041) and corneal fluorescein staining (p=0.002) was found when compared with pretreatment values. After 24u2005months Schirmer test values without local anaesthesia were significantly reduced in the treated eyes vis-à-vis untreated fellow eyes and pretreatment values (p=0.004). The dose applied to the lacrimal gland was significantly correlated to ocular surface staining scores (p=0.001) and Schirmer test values (p=0.026) at 24u2005months after irradiation. Conclusions Stereotactic single-fraction Gamma-Knife radiotherapy of choroidal melanoma with a median dose of 30u2005Gy significantly affected ocular surface and tear function and increased dry eye symptoms and signs.

New insights into oculodermal nevogenesis and proposal for a new iris nevus classification

Background/aims To gain more knowledge about presence and dermatological associations of iris nevi as well as possible pathways involved in the formation of iris nevi. Methods We conducted a prospective, interdisciplinary observational study. Presence, morphology, topography of iris and cutaneous nevi as well as factors indicating sun-exposure were noted. Results A total of 632 participants including 360 (57%) women were examined. Of those, 26 subjects revealed 27 iris nevi. According to the current classification, all iris nevi were judged as solitary with the majority of them (n=20; 74%) located in the lower quadrants. In six (22.2%) cases we noted a peculiar incomplete sectoral pattern; these nevi were located close to the pupil, were larger and had a more elongated, triangular shape compared with those located distant from the pupil, which appeared smaller and more roundish. Notably, five of these six peculiar (incomplete sectoral) iris nevi were located on the upper half of the iris. Conclusions Based on our findings we propose classifying iris nevi into sectoral, incomplete sectoral and solitary subtypes. Additionally, we set up a hypothetic concept of oculodermal nevogenesis suggesting a time-dependent embryogenic alteration affecting the normal melanocyte location, migration and maturation along peripheral nerve sheets. Our new concept explains well the morphology and extension of benign melanocytic proliferations in the ocular region as well as their relation to uveal melanoma.

Iris Freckles a Potential Biomarker for Chronic Sun Damage.

PurposenTo investigate the role of sunlight exposure in iris freckles formation.nnnMethodsnWe prospectively examined volunteers attending a skin cancer screening program conducted by ophthalmologists and dermatologists. Frequency and topographical variability of iris freckles were noted and associated with behavioral and dermatologic characteristics indicating high sun exposure.nnnResultsnSix hundred thirty-two participants (n = 360; 57% female) were examined. Mean age of all participants was 38.4 ± 18.4 years (range, 4-84 years). Of all individuals, 76.1% (n = 481) exhibited at least one iris freckle. Most freckles were observed in the inferior temporal quadrant. The presence of iris freckles was associated with higher age (participants with iris freckles: 41.8 ± 16.8 years versus participants without iris freckles: 27.6 ± 19.2 years), a high number of sunburns during lifetime (>10: 31% vs. 19%), sunlight-damaged skin (26% vs. 11%), presence of actinic lentigines (72% vs. 45%), and a high total nevus body count (>10; 78% vs. 67%).nnnConclusionsnThe association of iris freckles, behavioral factors, and dermatologic findings, as well as the topographical distribution, indicate that sunlight exposure may trigger the formation of iris freckles. The evaluation of iris freckles offers an easily accessible potential biomarker, which might be helpful in indicating sun damage on the skin associated with cutaneous malignancies. Furthermore, the evaluation of iris freckles could also be helpful in understanding the role of sunlight in several ophthalmologic diseases.