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BAYRİ, YAŞAR

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BAYRİ

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YAŞAR

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  • Thumbnail Image
    PublicationOpen Access
    A new method for quantification of frontal retrusion and complex skull shape in metopic craniosynostosis: a pilot study of a new outcome measure for endoscopic strip craniectomy
    (2022-06-01) SAÇAK, BÜLENT; ERDOĞAN, ONUR; BAYRİ, YAŞAR; DAĞÇINAR, ADNAN; SAKAR, MUSTAFA; SÖNMEZ, ÖZCAN; SAKAR M., Haidar H., SÖNMEZ Ö., ERDOĞAN O., SAÇAK B., BAYRİ Y., DAĞÇINAR A.
    OBJECTIVE The objective of this study was to propose a new skull outline–based method to objectively quantify complex 3D skull shapes and frontal and supraorbital retrusion in metopic craniosynostosis using 3D photogrammetry. METHODS A standard section from 3D photogrammetry, which represents the trigonocephalic shape, was used in this study. From the midpoint of the area of this section, half diagonals were calculated to the skull outline at 5° increments in the anterior half of the head. These half diagonals were used to create a sinusoidal curve, and the area under the sinusoidal curve (AUC) was used to represent the mathematical expression of the trigonocephalic head shape. The AUC from 0° to 180° (90° from the midline to each side) was calculated and is referred to as AUC0→180. The AUC from 60° to 120° (30° from the midline to each side) was also calculated and is referred to as AUC60→120. A total of 24 patients who underwent endoscopic strip craniectomy and 13 age- and sex-matched controls were included in the study. The AUC values obtained in patients at different time points and controls were analyzed. RESULTS The mean preoperative AUC60→120 and AUC0→180 in the patients were significantly lower than those in control individuals. The increase in both AUC60→120 and AUC0→180 values is statistically significant at the discontinuation of helmet therapy and at final follow-up. Receiver operating characteristic curve analysis indicated that AUC60→120 is a more accurate classifier than AUC0→180. CONCLUSIONS The proposed method objectively quantifies complex head shape and frontal retrusion in patients with metopic craniosynostosis and provides a quantitative measure for follow-up after surgical treatment. It avoids ionizing radiation exposure
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    PublicationOpen Access
    Long-term outcomes of gamma-knife radiosurgery for intracanalicular vestibular schwannomas
    (2022-01-01) PINAR, ERTUĞRUL; BAYRİ, YAŞAR; BAYRAKLI, FATİH; SAKAR, MUSTAFA; ATASOY, BESTE MELEK; Sakar M., Pınar E., Bayri Y., Bayraklı F., Atasoy B. M., Ziyal M. İ.
    GİRİŞ ve AMAÇ: Kanal içi vestibüler schwannomalar, tüm vestibüler schwannomalar içerisinde küçük bir yüzdeye sahiptir. Kanal içi vestibüler schwannomalarda işitmenin korunması, hasta yönetiminin temel amaçlarındandır. Bu çalışmanın amacı, kanal içi vestibüler schwannomalarda Gamma-Knife radyocerrahinin (GKR) tümör kontrolü ve işitmenin korunması üzerine etkisinin incelenemesidir.YÖNTEM ve GEREÇLER: Bu geriye dönük çalışmada, Gamma-Knife Radyocerrahi Merkezi’mizde Ocak 2010–Ocak 2020 arasında kanal içi vestibüler schwannoma tanısı ile stereotaksik radyocerrahi almış, klinik, odyometrik ve radyolojik takibi bulunan hastalar değerlendirildi. Tümör kontrolü manyetik rezonans görüntüleme yönteminde tümör boyutlarının ölçülmesi ile takip edildi. İşitme seviyeleri Gardner-Robertson (GR) işitme sınıflaması yöntemine göre değerlendirildi.BULGULAR: Ortalama 48.23 aylık takipte, çalışmaya dahil edilen toplam 45 hastadan 44’ünde tümör kontrolü sağlandığı görüldü (%97.7). Tümör büyümesi görülen bir hastada ise, ek bir tedavi uygulanması gerekmedi. Ek tedavi gerekliliğine göre değerlendirildiğinde tüm hastalarda tümör kontrolü sağlandı (%100). Tedavi öncesi fonksiyonel işitmesi olan (GR derece I ve II) toplam 29 hastadan, ortalama 70.42 aylık takip sonrasında, toplam 13 hastada fonksiyonel işitme korundu (%44.8). GR derecesinde kayıp, ameliyat öncesinde yüksek GR derecesine sahip olmak ile korelasyon gösterdi (Rs=0.459, p=0.002). Tedavi dozu işitme kaybı ile korelasyona sahipti ve daha yüksek doz alan hastalar daha kötü sonuçlara sahipti (Rs=0.459, p=0.002).TARTIŞMA ve SONUÇ: Kanal içi vestibüler schwannomalarda GKR uzun dönemli takiplerde mükemmel tümör kontrolü sağlamaktadır. Beş yılın üzerindeki takip sürelerinde fonksiyonel işitmenin korunma oranı azalabilir. Kanal içi vestibüler schwannomalarda GKR sonrası işitmenin seyrini ortaya koyabilmek için uzun takip süreli daha fazla çalışma gerekmektedir.Anahtar Kelimeler:Gamma-knife radyocerrahi, işitmenin korunması; kanal içi; tümör kontrolü; vestibüler schwannoma.
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    PublicationOpen Access
    Comparative analysis of linezolid, vancomycin, and hyperbaric oxygen therapies in a rat model of ventriculoperitoneal shunt infection
    (2024-06-01) ŞAHİN, YENER; SAYIN, ELVAN; BAYRİ, YAŞAR; ŞAHİN Y., SAYIN E., Aslan Y., BAYRİ Y.
    Purpose: Staphylococcus epidermidis is the most common causative microorganism of ventriculoperitoneal shunt infections. This study aimed to compare linezolid and vancomycin treatments and to examine the effect of these antibiotics alone and combined with hyperbaric oxygen therapy on the amount of bacterial colonies in the experimental S. epidermidis shunt infection model. Methods: A shunt catheter was placed in the cisterna magna of 49 adult male Wistar albino rats. The rats were randomly divided into seven groups, as follows: sterile control, infected control, vancomycin, linezolid, hyperbaric oxygen, vancomycin + hyperbaric oxygen, linezolid + hyperbaric oxygen. In all groups except the sterile control group, 0.2 ml 107 CFU/mL S. epidermidis was inoculated to the cisterna magna. Parenteral vancomycin was administered 40 mg/kg/day to the vancomycin groups, and 50 mg/kg/day of enteral linezolid to the linezolid groups. Hyperbaric oxygen groups were given 100% oxygen at a pressure of 2.4 ATA for 50 min a day. One day after the last treatment, colony quantities in the shunt catheters and CSF were analyzed. Results: The number of CSF colonies in the linezolid group was significantly lower than in the vancomycin group (p < 0.05). The number of CSF colonies in the linezolid + HBO group was significantly lower than in the vancomycin + HBO group (p < 0.05). Conclusions: Linezolid treatment was found to be more effective than vancomycin in ventriculoperitoneal shunt infection caused by S. epidermidis. There was no statistical difference among other treatment groups. Hyperbaric oxygen therapy is shown to contribute to the sterilization of cultures.