The Percent Volume Altered in Correction of Myopia and Myopic Astigmatism With PRK, LASIK, and SMILE.

PURPOSE: To determine the volumes altered during photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE) correction of myopia and myopic astigmatism. METHODS: The volumes of stromal tissue affected by surgical correction of pure and astigmatic myopia were calculated in this theoretical study for PRK, LASIK, and SMILE treatments. These results were then used to calculate representative values for percent volume altered (PVA) restricted to stromal corneal tissue. RESULTS: For the same spherical equivalent, there were remarkable differences between the amount of tissue removed between pure and compound myopic corrections. The PVA of LASIK procedures was the largest, whereas the PVA was comparable between PRK and SMILE. PRK had the lowest PVA for low myopic and compound astigmatic corrections and SMILE had the lowest PVA for high myopic and compound myopic astigmatism procedures. CONCLUSIONS: The comparison of volumes of tissue removed and PVA values of different treatment modalities provided in this study may give clinicians an improved understanding about the potential influence of geometrical parameters of those methods on the biomechanics of the cornea. [J Refract Surg. 2020;36(12):844-850.].

Octenidine in combination with polymethylmethacrylate: a new option for preventing infection?

BACKGROUND: Orthopedic implant infections represent a serious complication for both patient and surgeon. In order to minimize this risk, it has become standard practice in surgery and orthopedics to add antimicrobial substances to the polymethylmethacrylate (PMMA) bone cement. The aim of this study is to find new options for preventing infection by using alternative adjuvants in combination with PMMA. We hypothesized, that Octenidine, after being combined with PMMA, can be released in vitro and an antimicrobial efficacy of discharged Octenidine can be shown. METHODS: The release of Octenidine from PMMA was assessed in high pressure liquid chromatography of the supernatant. In order to assess the efficacy of Octenidine on Staphylococcus aureus and Pseudomonas aeruginosa in vitro, a nutrient solution for these bacteria was incubated with a defined number of these bacteria (10(6) colony forming units) and cement pellets containing the antiseptic Octenidine for 24 h. After the incubation the number of bacteria in the solution was determined by counting the colony forming units on blood agar plates. RESULTS: Octenidine was shown to be released in a concentration-dependent manner from PMMA in the elution experiment. The experimental procedure using S. aureus demonstrated a bactericidal effect for bone cement containing Octenidine. For P. aeruginosa, bone cement containing 5-8% Octenidine was associated with tenfold reduction in bacterial count. CONCLUSION: These results suggest that Octenidine is released after combining it with PMMA and reaches working concentrations in vitro. These findings suggest a new and effective alternative for prevention of infection in cemented implants. Further investigations on the biocompatibility of this combination is needed.

Integrated FDG-PET-CT: its role in the assessment of bone and soft tissue tumors.

PURPOSE: The purpose of this study was to evaluate prospectively, whether integrated 2-deoxy-2-[(18)F]fluoro-D: -glucose positron emission tomography-computed tomography (FDG-PET-CT) is more accurate for determination musculoskeletal tumors compared with separate interpretation of CT and FDG-PET, because most of the current clinical data come from patients studied with PET. METHODS: Eighty patients with newly diagnosed musculoskeletal tumors underwent FDG-PET-CT. CT, FDG-PET, and FDG-PET-CT were interpreted separately to determine the performance of each imaging modality. RESULTS: Assuming that equivocal lesions are benign, performance of diagnostic tests was as follows: sensitivity, specificity and accuracy for CT alone was 81, 84, 83%, for PET 71, 82, 76, and for PET-CT 80, 83 and 86%. Assuming that equivocal lesions are malignant, sensitivity, specificity, and accuracy for CT was 61, 100, 70%, for PET 69, 100, 79, and for PET-CT 69, 100 and 79%. CONCLUSIONS: Combined FDG-PET-CT reliably differentiates soft tissue and bone tumors from benign lesions. The value of the information provided by FDG-PET-CT for planning surgical procedures must be evaluated in further studies.

First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results.

PURPOSE: To prospectively study the feasibility of femtosecond lenticule extraction (FLE), a new method of refractive correction. SETTING: Department of Ophthalmology, Philipps University of Marburg and Helios Clinic, Erfurt, Germany. METHODS: A flap and a lenticule of intrastromal corneal tissue were simultaneously cut with a VisuMax femtosecond laser system. Next, the lenticule was manually removed and the flap repositioned. The target refraction in all cases was -0.75 diopter (D). RESULTS: All 10 myopic eyes in the initial treatment group completed the final 6-month follow-up. The mean patient age was 39 years. The mean spherical equivalent (SE) was -4.73 +/- 1.48 (SD) preoperatively and -0.33 +/- 0.61 D 6 months postoperatively. Ninety percent of eyes were within +/-1.00 D and 40% were within +/-0.50 D of the intended correction. No eye lost 2 or more Snellen lines. Corneal topography showed large, prolate optical zones. Aberrometry showed no significant induction of higher-order aberrations. On a standardized questionnaire, all patients said they were very satisfied with the results. CONCLUSIONS: Preliminary results indicate that FLEx [corrected] is a promising new corneal refractive procedure to correct myopia.

Imaging bone and soft tissue tumors with the proliferation marker [18F]fluorodeoxythymidine.

PURPOSE: We have determined the ability of positron emission tomography (PET) with the thymidine analogue 3'-deoxy-3'[18F]fluorothymidine (FLT) to detect manifestation sites of bone and soft tissue tumors, to assess tumor grading, and to differentiate malignant from benign tumors. MATERIALS AND METHODS: In this prospective bicenter trial, FLT-PET was done in 22 patients with established or suspected soft or bone tissue lesions. Routine diagnostic procedures included incisional biopsy, magnetic resonance imaging, and/or contrast-enhanced spiral computed tomography in all patients and [18F]fluorodeoxyglucose (FDG)-PET in 15 patients. Forty-five to 60 minutes after i.v. injection of 350 to 425 MBq FLT, emission and transmission scanning was done. Tracer uptake in the tumor was evaluated semiquantitatively by calculation of mean and maximum standardized uptake values (FLT-SUV) and compared with respective values of FDG. Results were correlated to histopathology and tumor grading. RESULTS: FLT-PET detected all malignant bone or soft tissue tumors (17 of 17). Mean FLT-SUV in benign lesions was 0.7 (range, 0.3-1.3), and 1.3 in low-grade sarcoma (grade 1; range, 1.0-1.6), 4.1 (range, 2.2-6.0; P = 0.002) and 6.1 (range, 2.5-8.3; P = 0.001) in grade 2 and grade 3 tumors, respectively. FLT but not FDG uptake correlated significantly with tumor grading (r = 0.71 versus r = 0.01), and a cutoff value of 2.0 for FLT-SUV discriminated between low- and high-grade tumors. CONCLUSION: In this clinical study, the proliferation marker FLT was suitable for imaging malignant bone or soft tissue tumors. FLT but not FDG uptake correlated significantly with the tumor grade, suggesting FLT as superior PET tracer for noninvasive grading of sarcomas.

Nonsteroidal anti-inflammatory drugs (NSAIDs) in the perioperative phase in traumatology and orthopedics effects on bone healing.

OBJECTIVE: To achieve analgesic, anti-inflammatory and antipyretic effects in traumatology and orthopedic surgery without side effects or with the least possible side effects, with special emphasis on bone healing. INDICATIONS: Acute and chronic inflammatory conditions, e. g., rheumatoid arthritis, ankylosing spondylitis. Degenerative joint disease. Posttraumatic and postoperative pain, edema, or fever. Prevention of heterotopic bone formation. CONTRAINDICATIONS: Hypersensitivity. Gastrointestinal ulceration or bleeding. Severe hepatic or renal impairment. RESULTS: Nonsteroidal anti-inflammatory drugs (NSAIDs) are invaluable in treating a variety of musculoskeletal conditions. As well as their excellent analgesic potency their anti-inflammatory effects are beneficial in treating posttraumatic and postoperative edema. In addition, NSAIDs inhibit heterotopic bone formation after hip arthroplasty. Animal studies, however, have demonstrated that they cause delayed fracture healing. Although clinical studies have not yet supplied unequivocal evidence of this effect in human subjects, the authors recommend that in the presence of other risk factors which may adversely affect fracture healing, such as smoking, diabetes mellitus or peripheral arterial occlusive disease, the indication of NSAID use for analgesia should be strictly limited. Therapeutic alternatives such as centrally acting agents (e. g., weak opioids) should be considered in these patients.