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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
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Publication Open Access Preliminary results of a new intercalary modular endoprosthesis for the management of diaphyseal bone metastases(Turkish Joint Diseases Foundation, 2021) Göker, Barlas; Tokgözoğlu, Mazhar; İnan, Ulukan; Özkan, Korhan; Çolak, Tahsin Sami; Ayvaz, Mehmet; Büyükdoğan, Kadir; Aslan, Lercan; Deveci, Mehmet Ali; Doctor; Faculty Member; Faculty Member; School of Medicine; Koç University Hospital; N/A; N/A; 206311Objectives: this study aims to evaluate functional outcomes of patients and to analyze complication rates of modular intercalary endoprosthetic reconstruction after resection of metastatic diaphyseal bone lesions. Patients and methods: between December 2017 and February 2020, 22 patients (15 males, 7 females; median age: 64.2 years; range, 49 to 91) who underwent reconstruction with modular intercalary endoprostheses for metastatic bone tumors at five different centers were retrospectively analyzed. Age, sex, diagnosis, follow-up duration, previous treatments of patients, and resection lengths were recorded. The Musculoskeletal Tumor Society Scores (MSTS) were used to assess functional status of available patients at the final follow-up. Failures were categorized according to the Henderson classification. Results: locations of the resected tumors included 10 humeri (45.5%), five tibiae (22.7%), and seven femurs (31.8%). The length of the resected tissues ranged from 35 mm to 180 mm. Seven patients (31.8%) died of disease, and one patient died of pneumonia within follow-up period. The functional outcomes of surviving patients were satisfying with a median MSTS score of 86.9% (range, 70 to 100%) at a median follow-up of 17 months (range, 8 to 26). There were two cases of type II (9%), one cases of type IIIa (4.5%), two cases of type IIIb (9%), and one case of type IV (4.5%) failure. Complications were most commonly observed in tibial reconstructions. Conclusion: the good short-term functional results were achieved in surviving patients. Uncomplicated patients were able to perform daily living activities without limitations. The overall rate of complications was relatively low and, among them, mechanical problems were the most commonly encountered problems.Publication Open Access Contralateral vs. ipsilateral approach to superior hypophyseal artery aneurysms: an anatomical study and morphometric analysis(Frontiers, 2022) Hanalioğlu, Şahin; Kiriş, Talat; Aydın, Serdar; Yılmaz, Özgür; Akyoldaş, Göktuğ; Baran, Oğuz; Faculty Member; Faculty Member; Faculty Member; School of Medicine; Koç University Hospital; N/A; 132535; N/A; N/A; N/A; N/AIntroduction: surgical clipping of superior hypophyseal artery (SHA) aneurysms is a challenging task for neurosurgeons due to their close anatomical relationships. The development of endovascular techniques and the difficulty in surgery have led to a decrease in the number of surgical procedures and thus the experience of neurosurgeons in this region. In this study, we aimed to reveal the microsurgical anatomy of the ipsilateral and contralateral approaches to SHA aneurysms and define their limitations via morphometric analyses of radiological anatomy, three-dimensional (3D) modeling, and surgical illustrations. Method: five fixed and injected cadaver heads underwent dissections. In order to make morphometric measurements, 75 cranial MRI scans were reviewed. Cranial scans were rendered with a module and used to produce 3D models of different anatomical structures. In addition, a medical illustration was drawn that shows different sizes of aneurysms and surgical clipping approaches. Results: For the contralateral approach, pterional craniotomy and sylvian dissection were performed. The contralateral SHA was reached from the prechiasmatic area. The dissected SHA was approached with an aneurysm clip, and maneuverability was evaluated. For the ipsilateral approach, pterional craniotomy and sylvian dissection were performed. The ipsilateral SHA was reached by mobilizing the left optic nerve with left optic nerve unroofing and left anterior clinoidectomy. MRI measurements showed that the area of the prechiasm was 90.4 +/- 36.6 mm(2) (prefixed: 46.9 +/- 10.4 mm(2), normofixed: 84.8 +/- 15.7 mm(2), postfixed: 137.2 +/- 19.5 mm(2), p < 0.001), the distance between the anterior aspect of the optic chiasm and the limbus sphenoidale was 10.0 +/- 3.5 mm (prefixed: 5.7 +/- 0.8 mm, normofixed: 9.6 +/- 1.6 mm, postfixed:14.4 +/- 1.6 mm, p < 0.001), and optic nerves' interneural angle was 65.2 degrees +/- 10.0 degrees (prefixed: 77.1 degrees +/- 7.3, normofixed: 63.6 degrees +/- 7.7 degrees, postfixed: 57.7 degrees +/- 5.7 degrees, p: 0.010). Conclusion: anatomic dissections along with 3D virtual model simulations and illustrations demonstrated that the contralateral approach would potentially allow for proximal control and neck control/clipping in smaller SHA aneurysm with relatively minimal retraction of the contralateral optic nerve in the setting of pre- or normofixed chiasm, and ipsilateral approach requires anterior clinodectomy and optic unroofing with considerable optic nerve mobilization to control proximal ICA and clip the aneurysm neck effectively.Publication Open Access Undifferentiated pleomorphic sarcoma of skin in unusual locations: report of two cases(Bayçınar Tıbbi Yayıncılık ve Reklam Hizmetleri, 2021) Eralp, İbrahim Levent; Aslan, Lercan; Baş, Ali; PhD Student; Faculty Member; Koç University HospitalUndifferentiated pleomorphic sarcoma (UPS) of the skin is a rare soft tissue sarcoma subtype with a high risk of metastasis and local recurrence. Ultraviolet exposure plays a prominent role in its etiology. Herein, we present two rare cases of UPS of the skin with an occurrence in non-ultraviolet exposed locations and discuss the need of wide resection and the identification of the depth of the tumor. Due to the resection of the skin, resulting defect was undertaken with skin grafting. One case was extending to the fascia and, after the resection, vacuum-assisted closure therapy was used for the formation of granulation tissue. No recurrence was seen after three and four years for either cases. In conclusion, UPS is a rare, aggressive malignant tumor with a high local recurrence and metastasis rate. Suspicion of malignancy in a plaque-like or nodular lesion in the skin is crucial, and local recurrence and metastasis risk is significantly correlated to the success of wide excision.Publication Open Access Gamma Knife radiosurgery for anterior clinoid process meningiomas: a series of 61 consecutivepatients(Elsevier, 2020) YIlmaz, Meltem; Şengöz, Meriç; N/A; Akyoldaş, Göktuğ; Hergünsel, Ömer Batu; Peker, Selçuk; Faculty Member; Graduate School of Health Sciences; School of Medicine; N/A; N/A; 11480Objective: gamma Knife radiosurgery (GKRS) outcomes for anterior clinoid process (ACP) meningiomas have not been specifically reported within any meningioma series. We present the initial and largest series in the literature that describes the presenting features, radiosurgery parameters, and radiologic and long-term clinical outcomes for 61 patients with ACP meningiomas treated with GKRS. Methods: medical records were reviewed for 61 consecutive patients at a single center who underwent GKRS for ACP meningioma between 2008 and 2016. Results: of 61 patients with ACP meningiomas, 49 (80%) were treated with GKRS as primary treatment, and 12 (20%) were treated with GKRS as an adjuvant therapy. Before GKRS, 29 patients presented with visual impairment and 50 patients presented with headache. Median patient age was 54.9 years. Median tumor volume was 3.2 cm(3), and median margin dose was 12.0 Gy. The median radiologic follow-up time after GKRS was 75 months. During follow-up, tumor volume regressed in 37 cases (61%) and remained unchanged in 24 cases (39%). None of the patients experienced tumor volume progression. Tumor volume <3 cm(3) was an independent predictor of tumor volume regression after GKRS (univariate analysis, P = 0.047; multivariate analysis, P = 0.049). Of 29 patients who presented with visual impairment, 16 (55%) improved after GKRS. None of the 61 patients developed new neurologic deficits after GKRS. Conclusions: GKRS provides a high rate of tumor volume control for ACP meningiomas as well as a low complication rate. Excellent tumor volume control was associated with smaller tumor size only.Publication Open Access A novel and simple machine learning algorithm for preoperative diagnosis of acute appendicitis in children(Springer, 2020) Türkmen, İnan Utku; Namlı, Gözde; Özturk, Çiğdem; Esen, Ayşe B.; Eray, Y. Nur; Akova, Fatih; Aydın, Emrah; Eroğlu, Egemen; Faculty Member; faculty Member; School of Medicine; 32059; N/AIntroduction: there is a tendency toward nonoperative management of appendicitis resulting in an increasing need for preoperative diagnosis and classification. For medical purposes, simple conceptual decision-making models that can learn are widely used. Decision trees are reliable and effective techniques which provide high classification accuracy. We tested if we could detect appendicitis and differentiate uncomplicated from complicated cases using machine learning algorithms. Materials and methods: we analyzed all cases admitted between 2010 and 2016 that fell into the following categories: healthy controls (Group 1); sham controls (Group 2); sham disease (Group 3), and acute abdomen (Group 4). The latter group was further divided into four groups: false laparotomy; uncomplicated appendicitis; complicated appendicitis without abscess, and complicated appendicitis with abscess. Patients with comorbidities and whose complete blood count and/or pathology results were lacking were excluded. Data were collected for demographics, preoperative blood analysis, and postoperative diagnosis. Various machine learning algorithms were applied to detect appendicitis patients. Results: there were 7244 patients with a mean age of 6.84 +/- 5.31 years, of whom 82.3% (5960/7244) were male. Most algorithms tested, especially linear methods, provided similar performance measures. We preferred the decision tree model due to its easier interpretability. With this algorithm, we detected appendicitis patients with 93.97% area under the curve (AUC), 94.69% accuracy, 93.55% sensitivity, and 96.55% specificity, and uncomplicated appendicitis with 79.47% AUC, 70.83% accuracy, 66.81% sensitivity, and 81.88% specificity. Conclusions: machine learning is a novel approach to prevent unnecessary operations and decrease the burden of appendicitis both for patients and health systems.Publication Open Access Rare malignant indications for liver transplantation: a collaborative transplant study report(Frontiers, 2021) Houben, Philipp; Schimmack, Simon; Unterrainer, Christian; Doehler, Bernd; Mehrabi, Arianeb; Süsal, Caner; Other; School of Medicine; 351800Introduction: hepatocellular carcinoma (HCC) is by far the leading malignant indication for liver transplantation (LT). Few other malignancies, including cholangiocellular carcinoma (CCC), metastases from neuroendocrine tumors (NET), and sarcomas of the liver (LSAR), also are commonly accepted indications for LT. However, there is limited information on their outcome after LT. Methods: graft and patient survival in 14,623 LTs performed in patients with hepatocellular carcinoma, CCC, NET, and LSAR from 1988 to 2017 and reported to the Collaborative Transplant Study were analyzed. Results: the study group consisted of 13,862 patients who had HCC (94.8%), 498 (3.4%) who had CCC, 100 (0.7%) who had NET, and 163 (1.1%) who had LSAR. CCC patients showed a 5-year graft survival rate of 32.1%, strikingly lower than the 63.2% rate in HCC, 51.6% rate in NET, and 64.5% rate in LSAR patients (P < 0.001 for all vs. CCC). Multivariable Cox regression analysis revealed a significantly higher risk of graft loss and death due to cancer during the first five post-transplant years in CCC vs. HCC patients (HR 1.77 and 2.56; P < 0.001 for both). The same risks were increased also in NET and LSAR patients but did not reach statistical significance. Conclusion: among patients with rare malignant indications for LT, CCC patients showed significantly impaired graft as well as patient survival compared to HCC patients. The observed differences might challenge traditional decision-making processes for LT indication and palliative treatment in specific hepatic malignancies.Publication Open Access Sparing sphincters and laparoscopic resection improve survival by optimizing the circumferential resection margin in rectal cancer patients(Elsevier, 2016) Keskin, M.; Bayraktar, A.; Sivirikoz, E.; Yeğen, G.; Karip, B.; Sağlam, E.; Bulut, M. T.; N/A; Balık, Emre; Faculty Member; School of Medicine; 18758The goal of rectal cancer treatment is to minimize the local recurrence rate and extend the disease-free survival period and survival. For this aim, obtainment of negative circumferential radial margin (CRM) plays an important role. This study evaluated predictive factors for positive CRM status and its effect on patient survival in mid- and distal rectal tumors. Patients who underwent curative resection for rectal cancer were included. The main factors were demographic data, tumor location, surgical technique, neoadjuvant therapy, tumor diameter, tumor depth, lymph node metastasis, mesorectal integrity, CRM, the rate of local recurrence, distant metastasis, and overall and disease-free survival. Statistical analyses were performed by using the Chi-squared test, Fisher exact test, Student t test, Mann-Whitney U test and the Mantel-Cox log-rank sum test. A total of 420 patients were included, 232 (55%) of whom were male. We observed no significant differences in patient characteristics or surgical treatment between the patients who had positive CRM and who had negative CRM, but a higher positive CRM rate was observed in patients undergone abdominoperineal resection (APR) (P < 0.001). Advanced T-stage (P < 0.001), lymph node invasion (P = 0.001) and incomplete mesorectum (P = 0.007) were encountered significantly more often in patients with positive CRM status. Logistic regression analysis revealed that APR (P < 0.001) and open resection (P = 0.046) were independent predictors of positive CRM status. Moreover, positive CRM was associated with decreased 5-year overall and disease-free survival(P = 0.002 and P = 0.004, respectively). This large single-institution series demonstrated that APR and open resection were independent predictive factors for positive CRM status in rectal cancer. Positive CRM independently decreased the 5-year overall and disease-free survival rates.Publication Open Access Superiorly based nasolabial island flap for reconstruction of the lateral lower eyelid(TÜBİTAK, 2017) Tatar, Sedat; Yontar, Yalçın; N/A; Özmen, Selahattin; Faculty Member; School of MedicineBackground/aim: Various flap procedures have been described and used for the lower eyelids; however, the nasolabial flap is rarely employed. We herein aimed to present the clinical results of using the superiorly based nasolabial island flap for repair of surgical defects extending to the lateral lower eyelid. Materials and methods: Nine patients with a mean age of 62 + 6 years underwent surgery for reconstruction of the lower eyelid. Results: The diagnosis of lesions was nodular basal-cell carcinoma (n = 5), superficial basal-cell carcinoma (n = 1), well-differentiated squamous-cell carcinoma (n = 1), and basosquamous-cell carcinoma (n = 2). According to the classification reported by Spinelli and Jelks, 6 surgical defects were located at zones II and IV, while 3 were at zones II and V. Five patients required posterior lamellar reconstruction. Lagopthalmos (n = 1), ectropion (n = 1), and transient numbness of the ipsilateral upper lip (n = 1) were noted as postoperative complications. Conclusion: Despite the low number of patients, the present series demonstrated that lower eyelid defects involving zone IV or zone V can be repaired safely and reliably with the superiorly based nasolabial island flap, along with its use shown in the literature for zone II or zone III defects. The technique for raising the flap is fairly simple, with predictable surgical results. In addition, the superiorly based nasolabial island flap provides a reliable means of obtaining good wound healing with acceptable aesthetics, as well as functional results of both the donor site and reconstructed area.Publication Open Access Retrorectal tumor: a single-center 10-years' experience(Korean Surgical Society, 2020) Yalav, Orçun; Topal, Uğur; Eray, İsmail Cem; Gencel, Eyüphan; Rencüzoğulları, Ahmet; Deveci, Mehmet Ali; Faculty Member; School of MedicinePurpose: retrorectal tumors [RTs] are a rare incidence and recommendations on the ideal surgical approaches are lacking. This study aimed to evaluate outcomes and follow-up results of patients undergoing excision of RTs at our institution. Methods: a retrospective review was conducted for undergoing surgery for RT between January 2009 and January 2019. Demographic characteristics, presenting symptoms, preoperative diagnostic tests, surgical procedures, histopathological results, intraoperative and postoperative complications, postoperative hospital stay, postoperative 30-day mortality, 90-day unplanned readmission rate, and long-term outcomes were evaluated. Results: twenty patients with a mean age of 48.3 +/- 14.2 were analyzed. The most common presenting complaint was perineal pain (35.0%). Magnetic resonance imaging and computed tomography was preferred in 18 and 2 patients, respectively. Tumor localization was below the level of the third sacral vertebrae in 14 patients for whom the posterior surgical approach was used. No postoperative mortality was recorded at the end of follow-up of 53.8 +/- 40 months. Mean length of postoperative hospital stay was 8.6 +/- 9.4 days. Ten percent of the patients had unplanned hospital readmission within 90 days after discharge. Recurrence developed in 1 patient, for whom pathology were reported as chordoma. conclusion: RT should be managed by a multidisciplinary team given the complexity and heterogeneity of these tumors despite the fact that the majority are benign. A good understanding of pelvic anatomy and characterization of lesions through detailed radiological imaging is crucial to optimize surgical planning. Complete surgical resection is key for prolonged disease-free and overall survival of patients diagnosed with RTs.Publication Open Access Does voiding cystourethrogram exclude posterior urethral valves in late presenting cases?(Thieme Medical Publishers, 2019) Büyükünal, Cenk; N/A; N/A; Özen, Mehmet Ali; Taşdemir, Mehmet; Gündoğdu, Gökhan; Bilge, İlmay; Eroğlu, Egemen; Faculty Member; Doctor; Faculty Member; Faculty Member; School of Medicine; N/A; 175867; N/A; 198907; N/AIntroduction: delayed presentation of posterior urethral valves (PUVs) is a rare condition. Presentation and diagnosis of the patients with late PUVs are challenging. Voiding cystourethrogram (VCUG) is mainly practiced. In this study, we aimed to evaluate the children with late-presented PUVs, and the reliability of VCUG in this group. Materials and methods: between January 2003 and December 2017 records of patients who were diagnosed with late-presented PUVs were analyzed. Delayed presentation of PUV was defined as patients who were diagnosed and treated after infancy. Cases were examined in terms of age at diagnosis, presenting symptoms, urinalysis, urinary ultrasound, urodynamic studies, VCUG, and dimercaptosuccinic acid scintigraphy findings. Postoperative follow-up conditions were also assessed. Results: seventeen boys were diagnosed with late-presented PUVs (mean age was 7.35 years). The most common symptoms at presentation were frequency (58.8%), day and nighttime incontinence (47%), and febrile urinary infection (41%). PUV was noted by VCUG in 10 patients alone. The classical sign of dilated posterior urethra was detected in 9 patients. The 10th patient had posterior urethral irregularity. Urethra could not be evaluated due to unsuccessful voiding in one patient. Six patients had normally appearing urethra on VCUG. Reflux was detected in nine (52.9%) patients. Conclusion: late-presented PUVs may be missed on VCUG. Whether a PUV might be present is crucial in boys with a history of recurrent urinary infection, persistent reflux, and repetitive daytime incontinence. Based on our results, we conclude that cystoscopic examination should be preferred for those cases to diagnose PUVs regardless of VCUG results.