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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
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Publication Open Access Outcome of extended right lobe liver transplants(Wiley, 2021) Lozanovski, Vladimir J.; Unterrainer, Christian; Dohler, Bernd; Mehrabi, Arianeb; Süsal, Caner; Other; School of Medicine; Koç University Hospital; 351800Split-liver transplantation offers a solution to the organ shortage problem. However, the outcomes of extended right lobe liver transplantation (ERLT) and whether it is a suitable alternative to full-size liver transplantation (FSLT) remain controversial. We compared the outcomes of ERLT and FSLT in adult recipients of 43,409 first deceased donor liver transplantations using Cox regression. We also analyzed 612 ERLT and 1224 FSLT 1:2 matched cases to identify factors that affect ERLT outcome. The risk of graft loss was significantly higher following ERLT than following FSLT during the first posttransplantation year in the matched and unmatched collective (hazard ratio [HR], 1.39 and 1.27 and P = 0.01 and 0.006, respectively). Every additional hour of cold ischemia time (CIT) increased the risk of 1-year graft loss by 10% in the ERLT group compared with only 3% in the FSLT group (P = 0.003 and <0.001, respectively). Importantly, the outcome of ERLT and FSLT did not differ significantly if the CIT was below 10 hours (HR, 0.71; P = 0.22). One-year graft and patient survival were lower in high-risk ERLT recipients with a Model for End-Stage Liver Disease (MELD) score of ?20 (HR, 1.88; P = 0.03 and HR, 2.03; P = 0.02). In the male recipient–male donor combination, ERLT recipients had a higher risk of 1-year graft loss than FSLT recipients (HR, 2.44; P = 0.006). This was probably because of the significantly higher MELD score in ERLT recipients (P = 0.004). ERLT in adults is an adequate alternative to FSLT and offers an elegant solution to the problem of organ shortage as long as the cold storage is less than 10 hours and the recipient’s MELD score is <20.Publication Open Access Isolated omental metastasis of renal cell carcinoma after extraperitoneal open partial nephrectomy : a case report(Elsevier, 2016) Sağlıcan, Yeşim; N/A; N/A; N/A; N/A; Acar, Ömer; Sağ, Alan Alper; Falay, Fikri Okan; Selçukbiricik, Fatih; Tabak, Levent; Esen, Tarık; Faculty Member; Faculty Member; Teaching Faculty; Faculty Member; Faculty Member; Faculty Member; School of Medicine; 237530; N/A; N/A; N/A; N/A; N/A; 50536INTRODUCTION: Metachronous metastatic spread of clinically localized renal cell carcinoma (RCC) affects almost 1/3 of the patients. They occur most frequently in lung, liver, bone and brain. Isolated omental metastasis of RCC has not been reported so far. CASE PRESENTATION: A 62-year-old patient previously diagnosed and treated due to pulmonary sarcoidosis has developed an omental metastatic lesion 13 years after having undergone open extraperitoneal partial nephrectomy for T1 clear-cell RCC. Constitutional symptoms and imaging findings that were attributed to the presence of a sarcomatoid paraneoplastic syndrome triggered by the development this metastatic focus complicated the diagnostic work-up. Biopsy of the [18F]-fluorodeoxyglucose (+) lesions confirmed the diagnosis of metastatic RCC and the patient was managed by the resection of the omental mass via near-total omentectomy followed by targeted therapy with a tyrosine kinase inhibitor. DISCUSSION: Late recurrence of RCC has been reported to occur in 10-20% of the patients within 20 years. Therefore lifelong follow up of RCC has been advocated by some authors. Diffuse peritoneal metastases have been reported in certain RCC subtypes with adverse histopathological features. However, isolated omental metastasis without any sign of peritoneal involvement is an extremely rare condition. CONCLUSION: To our knowledge, this is the first reported case of metachronously developed, isolated omental metastasis of an initially T1 clear-cell RCC. Constitutional symptoms, despite a long interval since nephrectomy, should raise the possibility of a paraneoplastic syndrome being associated with metastatic RCC. Morphological and molecular imaging studies together with histopathological documentation will be diagnosticPublication Open Access Multi-level anterior cervical decompression in multi-level cervical spondylotic myelopathy without extending the corpus resection: a cadaveric study of a novel surgical technique(Turkish Neurosurgical Society, 2021) Saygı, Tahsin; Özdemir, Ömer; Evran, Şevket; Kayhan, Ahmet; Özbek, Muhammet Arif; Erkan, Buruç; Demirel, Nail; Özdoğan, Selçuk; Baran, Oğuz; Faculty Member; Koç University HospitalAim: to perform three-level decompression with a single-level corpectomy by modifying the fusion with anterior cervical corpectomy (ACC-F) method on a cadaver. Material and methods: the anterior cervical region of four whole-head cadavers was dissected. The corpectomy was performed under a surgical microscope with a MT4-20+ ultrasonic bone dissector (UBD) tip. Superior and inferior decompression were conducted and viewed with a 70 degrees neuroendoscope using two types (vertically and horizontally oriented) of specially designed 23 mm-long, 90 degrees-angled UBD tips. Results: after neck dissection and the removal of the thyroid and cricoid cartilages, C5 corpectomy and adjacent-level discectomies were performed. Following discectomy and corpectomy, superior and inferior decompression were conducted with specially designed UBD tips and viewed with a 70 degrees neuroendoscope. A three-level anterior cervical decompression was provided with a single-level corpectomy. Conclusion: this study demonstrated that two more level decompression is possible with a single-level corpectomy in the cervical region using the new technique.Publication Open Access Outcomes of Norwood procedure with hypoplastic left heart syndrome: our 12-year single-center experience(Bayçınar Tıbbi Yayıncılık ve Reklam Hizmetleri, 2022) Özdemir, Fatih; Korun, Oktay; Dedemoğlu, Mehmet; Çiçek, Murat; Yurdakok, Okan; Altın, Hüsnü Fırat; Yılmaz, Emine Hekim; Yurtseven, Nurgül; Aydemir, Numan Ali; Sasmazel, Ahmet; Biçer, Mehmet; Koç University HospitalBackground: in this study, we aimed to analyze the predictors and risk factors of mortality in patients who underwent Norwood I procedure with the diagnosis of hypoplastic left heart syndrome. Methods: between January 2009 and December 2020, a total of 139 patients (95 males, 44 females) who underwent Norwood I procedure with the diagnosis of hypoplastic left heart syndrome in our center were retrospectively analyzed. Results: the median birth weight was 3,200 (range, 3,000 to 3,350) g and the median age at the time of operation was seven (range, 5 to 10) days. Pulmonary flow was achieved with a Sano shunt in the majority (72%) of patients. Survival rate was 41% after the first stage. Reoperation for bleeding (p=0.017), reoperation for residual lesion (p=0.011), and postoperative peak lactate level (p=0.029), were associated with in-hospital mortality. Nineteen (33%) of 57 patients died before the second stage. Thirty-three (58%) patients underwent second stage, and survival after the second stage was 94%. Thirteen patients underwent third stage, and survival after the third stage was 85%. Estimated probability of survival at six months, and one, two, three, and four years were 33%, 33%, 25%, 25%, and 22% respectively. Conclusion: hospital and inter-stage mortality rates are still high and this seems to be the most challenging period in term of survival efforts of the patients with hypoplastic left heart syndrome. Early recognition and reintervention of anatomical residual defects, close follow-up in the inter-stage period, and the accumulation of multidisciplinary experience may help to improve the results to acceptable limits. / Amaç: bu çalışmada, hipoplastik sol kalp sendromu tanısıyla Norwood I işlemi uygulanan hastalarda mortalitenin öngörücüleri ve risk faktörleri incelendi. Ça¬lış¬ma pla¬nı: Ocak 2009 ve Aralık 2020 tarihleri arasında merkezimizde hipoplastik sol kalp sendromu tanısıyla Norwood I işlemi uygulanan toplam 139 hasta (95 erkek, 44 kadın) retrospektif olarak incelendi. Bulgular: medyan doğum ağırlığı 3200 (dağılım, 3000-3350) g ve ameliyat sırasında medyan yaş yedi (dağılım, 5-10) gün idi. Hastaların büyük kısmında (%72) pulmoner akım, Sano şant ile sağlandı. İlk aşama sonrası sağkalım %41 idi. Kanama nedeniyle tekrar ameliyat (p=0.017), rezidü anatomik lezyon nedeniyle tekrar ameliyat (p=0.011) ve ameliyat sonrası birinci gün pik laktat seviyesi (p=0.029) hastane mortalitesi ile ilişkili idi. Taburcu edilen 57 hastanın 19’u (%33) ikinci aşamaya ulaşamadan kaybedildi. Otuz üç (%58) hastaya ikinci aşama ameliyatı uygulandı ve ikinci aşama sonrası sağkalım %94 idi. On üç hastaya üçüncü aşama ameliyatı uygulandı ve üçüncü aşama sonrası sağkalım %85 idi. Altı ay ve birinci, ikinci, üçüncü ve dördüncü yılda tahmini sağkalım olasılığı sırasıyla %33, %33, %25, %25 ve %22 idi. So¬nuç: hastane ve aşamalar arası mortalite oranları halen yüksek olup, hipoplastik sol kalp sendromu tanılı hastaların sağkalma çabalarındaki en zorlayıcı zaman dilimi olarak görünmektedir. Anatomik rezidü defektlerin erken tanılanması ve erken yeniden girişim yapılması, aşamalar arası dönemde yakın takip ve multidisipliner birikim ve tecrübe sonuçların kabul edilebilir seviyelere ulaşmasına yardım edebilir.Publication Open Access Posttransplant Hemophagocytic Lymphohistiocytosis in pediatric liver transplant recipients(Wiley, 2021) Arıkan, Çiğdem; Erbey, Mehmet Fatih; Akyıldız, Murat; Faculty Member; Undergraduate Student; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; Koç University Hospital; 240198; N/A; N/A; N/APublication Open Access Chitosan channels stuffed with mesenchyme originated stem/progenitor cells for renovate axonal regeneration in complete spinal cord transection(Turkish Neurosurgical Society, 2021) Çakıcı, Nazlı; Bozkurt, Gökhan; Puralı, Nuhan; Denkbaş, Emir Baki; Korkusuz, Petek; Uçkan Çetinkaya, Duygu; Başak, Ahmet Tulgar; Doctor; Koç University HospitalAim: to examine the implantation of chitosan channels stuffed with mesenchyme-originated stem/progenitor cells (MSPCs) derived from adult rats in a spinal cord transection model. The level of axonal regeneration, the effect of chitosan channels on the survival of MSPCs, and the functional recovery results were also evaluated. Material and methods: chitosan channels stuffed with MSPCs were implanted at the level of T8 in a transected rat spinal cord. MSPCs were harvested from the pelvic bone marrow of adult rats, and the MSPC-chitosan channel group was compared with three control groups. The axonal regeneration capacity, the effect of chitosan channels on the survival of MSPCs, and the functional recovery results were compared among four groups. The survival of MSPCs was evaluated using histopathological techniques and electron microscopy, axonal regeneration/germination was evaluated by confocal microscopy, and locomotor function was assessed for 4 weeks using the Basso, Beattie, and Bresnahan locomotor score. Results: the MSPC-chitosan channel group exhibited enhanced survival of transplanted MSPCs compared with MSPCs transplanted directly into the lesion cavity, although no significant difference was detected in locomotor function between the treatment and control groups. The MSPC-chitosan channel group demonstrated thicker myelination of axons than the other groups. Conclusion: chitosan channels promoted the survival of transplanted MSPCs and created a tissue bridge after complete spinal cord transection. They also induced axonal regeneration and germination. No significant improvement in functional recovery was found between the groups.Publication Open Access Tissue thiol concentration in high-grade gliomas: is there any association between IDH1 mutation presence and tumoral cellular antioxidant defense?(Turkish Neurosurgical Society, 2021) Evran, Şevket; Kayhan, Ahmet; Çevik, Serdar; Katar, Salim; Kaya, Mustafa; Sönmez, Derya; Serin, Huriye; Hanımoğlu, Hakan; Kaynar, Mehmet Yaşar; Baran, Oğuz; Faculty Member; Koç University HospitalAim: to assess and compare the antioxidant capacities of high-grade gliomas (HGG) according to their grades and the presence of isocitrate dehydrogenase 1 (IDH1) mutation using tissue thiol level measurement. Material and methods: tissue thiol concentrations were measured in 41 HGG samples and 21 healthy brain tissues obtained from autopsy procedures, which were performed within the first 4 hours of death. All samples were stored at -80 degrees C, and a thiol quantification kit was used in evaluating tissue thiol levels. The Number Cruncher Statistical System was used for statistical analyses to detect the differences between the control group and the HGG group, which was also divided into subgroups according to their grade and IDH1 mutation presence. Results: the tissue thiol levels of HGGs were found to be higher than the control group (p=0.001). Although the median thiol levels of Grade 4 gliomas were higher than those of Grade 3, no statistically significant difference was noted (p=0.076). When all tumors were compared according to the IDH1 mutation presence, IDH1-negative (IDH1-) HGGs had higher thiol contents than IDH1 mutant (IDH1+) HGGs (p=0.001). The thiol levels of Grade 4 IDH1- gliomas were statistically significantly higher than of Grade 3 gliomas (p=0.023), but no statistically significant difference between the thiol levels of Grade 3 and Grade 4 IDH1+ tumors was noted (p=0.459). Conclusion: we have demonstrated the higher thiol concentrations of HGGs, particularly IDH1- ones. The sulfhydryl contents of gliomas as an indicator of tumoral antioxidant capacity may be responsible for the treatment resistance of IDH1- gliomas, the mechanism of which is not clear. Thiols can be a novel target for treatment, considering the unsatisfactory results of current modalities for HGGs.Publication Open Access How to reduce stress on the pedicle screws in thoracic spine? Importance of screw trajectory: a finite element analysis(Turkish Neurosurgical Society, 2019) Güvenç, Yahya; Erbulut, Deniz; Akyoldaş, Göktuğ; Şentürk, Salim; Yaman, Onur; Özer, Ali Fahir; Faculty Member; Doctor; Doctor; Faculty Member; Koç University Hospital; N/A; N/A; N/A; 1022Aim: to investigate the biomechanical comparison of thoracic transpedicular screw trajectories on the sagittal plane. Material and methods: a three-dimensional, non-linear finite element analysis (FEA) model of T8 through T9 was used. Anatomic trajectory (AT) and Straightforward trajectory (ST) models of the transpedicular screws were used in the intact FEA model. The von-Mises stress and range of motion (ROM) of the transpedicular screws were evaluated. Results: the difference in ROM between both techniques was negligible. In lateral bending and axial rotation, FEA showed decrease in stress by 25% and 8%, respectively, when pedicle screws were placed using AT. Conclusion: AT decreased the von-Mises stress of the pedicle screws, thereby reducing the rates of screw breakage and fatigue risks. In addition, we believe that AT could protect against screw loosening because the von-Mises stress of the internal fixation was scattered.Publication Open Access Histopathological tumour response scoring in resected pancreatic cancer following neoadjuvant therapy: international interobserver study (ISGPP-1)(Oxford University Press (OUP), 2022) Janssen, Boris, V; van Roessel, Stijn; van Dieren, Susan; de Boer, Onno; Basturk, Olca; Brosens, Lodewijk; Campbell, Fiona; Chatterjee, Deyali; Chou, Angela; Doglioni, Claudio; Esposito, Irene; Feakins, Roger; Fuchs, Talia L.; Fukushima, Noriyoshi; Gill, Anthony J.; Hong, Seung-Mo; Hruban, Ralph H.; Kaplan, Jeffrey; Krasinkas, Alyssa; Luchini, Claudio; Shi, Chanjuan; Singhi, Aatur; Thompson, Elizabeth; Velthuysen, Marie-Louise F.; Besselink, Marc G.; Verheij, Joanne; Wang, Huamin; Verbeke, Caroline; Farina, Arantza; Adsay, Nazmi Volkan; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; 286248The ISGPP-1 study demonstrated that identifying the effect of neoadjuvant therapy in resected pancreatic cancer proved unreliable. The interobserver agreement for the current tumour response scoring (TRS) systems was suboptimal. A collaborative effort is required to develop an objective TRS system. Background Most tumour response scoring systems for resected pancreatic cancer after neoadjuvant therapy score tumour regression. However, whether treatment-induced changes, including tumour regression, can be identified reliably on haematoxylin and eosin-stained slides remains unclear. Moreover, no large study of the interobserver agreement of current tumour response scoring systems for pancreatic cancer exists. This study aimed to investigate whether gastrointestinal/pancreatic pathologists can reliably identify treatment effect on tumour by histology, and to determine the interobserver agreement for current tumour response scoring systems. Methods Overall, 23 gastrointestinal/pancreatic pathologists reviewed digital haematoxylin and eosin-stained slides of pancreatic cancer or treated tumour bed. The accuracy in identifying the treatment effect was investigated in 60 patients (30 treatment-naive, 30 after neoadjuvant therapy (NAT)). The interobserver agreement for the College of American Pathologists (CAP) and MD Anderson Cancer Center (MDACC) tumour response scoring systems was assessed in 50 patients using intraclass correlation coefficients (ICCs). An ICC value below 0.50 indicated poor reliability, 0.50 or more and less than 0.75 indicated moderate reliability, 0.75 or more and below 0.90 indicated good reliability, and above 0.90 indicated excellent reliability. Results The sensitivity and specificity for identifying NAT effect were 76.2 and 49.0 per cent respectively. After NAT in 50 patients, ICC values for both tumour response scoring systems were moderate: 0.66 for CAP and 0.71 for MDACC. Conclusion Identification of the effect of NAT in resected pancreatic cancer proved unreliable, and interobserver agreement for the current tumour response scoring systems was suboptimal. These findings support the recently published International Study Group of Pancreatic Pathologists recommendations to score residual tumour burden rather than tumour regression after NAT.Publication Open Access Surgical management of cardiac cystic echinococcosis in a pediatric patient: a case report(Oxford University Press (OUP), 2022) Altın, H.F.; Aydemir, N.A.; Biçer, Mehmet; Kozan, Şima; School of Medicine; Koç University HospitalCystic echinococcosis, a zoonotic parasitic disease, is endemic to many countries worldwide. This slowly progressing disease is seen rarely in the paediatric age group. In terms of cyst localization, cardiac involvement is infrequent. We report the case of a successful surgical and medical management of a paediatric hydatid disease patient with involvement of the heart.