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Featured researches published by Abdurrahman Onen.


Journal of Pediatric Urology | 2007

An alternative grading system to refine the criteria for severity of hydronephrosis and optimal treatment guidelines in neonates with primary UPJ-type hydronephrosis.

Abdurrahman Onen

OBJECTIVE We present our alternative hydronephrosis grading system (AGS) in an attempt to establish optimal treatment guidelines, and clarify and refine the criteria for severity of hydronephrosis in neonates. PATIENTS AND METHODS A total of 162 newborns (228 affected kidneys) with antenatally diagnosed primary ureteropelvic junction-type hydronephrosis were prospectively followed and treated by the same surgeon for a mean of 46 (6-65) months. Ultrasonography and diuretic renogram were used for diagnosis and follow up. Society for Fetal Urology (SFU) grading system, anteroposterior diameter of renal pelvis (APDRP) and our AGS were used to determine the degree of hydronephrosis. AGS: 0, no hydronephrosis; 1, dilatation of renal pelvis alone; 2, plus caliceal dilatation; 3, plus <1/2 (mild-to-moderate) renal parenchymal loss; 4, plus >1/2 (severe) renal parenchymal loss (cyst-like kidney with no visually significant renal parenchyma). RESULTS On the first postnatal ultrasound, the severity of hydronephrosis was SFU< or =2 in 152 kidneys (surgery, 0%), SFU-3 in 41 kidneys (surgery, 19.5%) and SFU-4 in 35 kidneys (surgery, 68.6%). The follow up, treatment and outcome of SFU-1 and SFU-2 patients were similar; all resolved spontaneously without renal deterioration (renal function >40%). Renal function ranged between 7% and 39% in SFU-4 patients. Intrarenal pelvis was found in one patient with an APDRP of <15 mm, seven patients of 16-30 mm, and five patients of >30 mm. Overall, 201 hydronephrotic kidneys (88.2%) resolved spontaneously while 27 (11.8%) required pyeloplasty. CONCLUSION Neither an SFU grading system nor measurement of APDRP is the gold standard in determining the severity of hydronephrosis. Both methods may fail, particularly in children with intrarenal pelvis configuration or SFU-4 hydronephrosis. Our AGS promises easier follow up and more timely treatment.


Journal of Pediatric Surgery | 2003

The effects of nitric oxide on the expression of cell adhesion molecules (ICAM-1, UEA-1, and tenascin) in rats with unilateral testicular torsion.

Hayrettin Öztürk; Hüseyin Büyükbayram; Enver Ozdemir; Aydın Ketani; Ahmet Gürel; Abdurrahman Onen; Selcuk Otcu

BACKGROUND/PURPOSE The aim of this study was to determine the effects of nitric oxide (NO) on the expression of adhesion molecules in the early course of testicular I-R injury in rats. METHODS Forty male Sprague-Dawley rats were separated into 4 groups, each containing 10 rats. A sham operation was performed in group 1 (control). In group 2 (I-R), after 6 hours of unilateral testicular torsion, 1-hour detorsion of the testis was performed. In group 3 (I-R/L-NAME), after performing the same surgical procedures as in group II, L-NAME was given for 30 minutes. In group 4 (I-R/Mol), after performing the same surgical procedure (torsion and detorsion) as in group II, molsidomine, an NO donor, was infused for 30 minutes. Then, ipsilateral orchiectomies were performed to measure the tissue levels of malondialdehyde (MDA) and NO and to make histologic examination. RESULTS MDA values and the testicular injury score decreased and NO values increased in the I-R/Mol-treated group compared with other experimental groups. The tenascin expression in the interstitial space and basement membrane of the tubuli seminiferi were milder in the I-R/Mol group compared with that of the I-R and the I-R/L-NAME. The acrosomes of the spermatids in I-R and I-R/L-NAME groups were stained mildly by lectin. In the I-R and I-R/L-NAME groups, the interstitial spaces, basement membrane of the tubuli seminiferi, and sertoli and germinal cells in testicular tissue were stained intensely by ICAM-1. CONCLUSIONS The expression of adhesion molecules such as tenascin, lectin, and ICAM-1 in the torted testicular tissue may be a pathophysiologic sign of inflammation. NO regulates adhesion molecules expression.


Surgery Today | 2007

Late Presentation of Bochdalek-Type Congenital Diaphragmatic Hernia in Children: A 23-Year Experience at a Single Center

Murat Kemal Cigdem; Abdurrahman Onen; Selcuk Otcu; Hanifi Okur

PurposeThe purpose of this article is to report on our 23-year experience of treating children with late-presenting congenital diaphragmatic hernia (CDH), focusing on diagnostic difficulties, associated anomalies, and morbidity.MethodWe reviewed 19 children in whom Bochdalek-type CDH was diagnosed after the neonatal period, between 1983 and 2005.ResultsThere were 14 boys and 5 girls, with a mean age of 18.3 months (range, 5 weeks–14 years). Ten (52.6%) of the patients presented with respiratory symptoms and five (26.3%) with gastrointestinal symptoms. The diagnosis of CDH was based on the findings of chest X-rays, gastrointestinal tract contrast radiographs, and computerized tomography findings. The CDH was on the left side in 16 patients and on the right side in three patients. A hernia sac was present in seven (36.8%) patients. The only postoperative complications were intestinal obstruction caused by adhesions, incisional hernia, and eventration of the diaphragm in one patient each. None of the patients died within this study period.ConclusionThe possibility of a delayed presentation of CDH should be considered in the differential diagnosis of recurrent non-specific respiratory or gastrointestinal tract symptoms in a child. A plain roentgenogram with a swallowed nasogastric tube might assist in the diagnosis. Early surgical correction of the diaphragmatic defect is crucial for preventing life-threatening complications.


Pediatric Surgery International | 2003

When to resect and when not to resect an asymptomatic Meckel's diverticulum: an ongoing challenge

Abdurrahman Onen; Murat Kemal Cigdem; Hayrettin Öztürk; Selcuk Otcu; Ali Ihsan Dokucu

Abstract. To determine the morbidity and mortality of Meckels diverticulum (MD) as a cause of acute abdominal disorders and to evaluate the relationship between patient age, MD complications, and postoperative complications. We reviewed 74 patients who underwent surgery between 1990 and 2000 for an acute abdominal syndrome with a MD diagnosed intraoperatively. Forty children were treated before 1995 and reviewed retrospectively, while the remaining 34 were reviewed prospectively. The average age was 4.8 years; the male/female ratio was 2.5/1; 34 (46%) were less than 2 years old, 32 were between 2 and 8 years, and 8 were older than 8 years. None of the symptoms was suggestive of the diagnosis of MD. Thirty-nine MDs were asymptomatic (21 intussusception, 18 volvulus), but all were the secondary cause of the acute abdomen. The remaining 35 children had a symptomatic MD (diverticulitis in 14, diverticular bleeding in 11, diverticular perforation in 10). The risk of complications due to a MD occurring in children under 2 years and between 2 and 8 years of age was significantly higher compared to children older than 8 years (P = 0.02). Postoperative complications occurred more commonly in children between 2 and 8 years of age compared to other patients. There is thus an increased risk of morbidity in a symptomatic MD in patients less than 2 and between 2 and 8 years of age, and there is no predictive factor for the development of diverticular complications. Resection of the MD is recommended in all children younger than 8 years, including asymptomatic ones, in the absence of absolute contraindications.


Toxicology Letters | 1998

The accumulation and histological effects of organometallic fungicides Propineb and Maneb in the kidneys of fetus and female rats during pregnancy.

Kemal Guven; Engin Deveci; Osman Akba; Abdurrahman Onen; David I. de Pomerai

Dithiocarbamate propineb and maneb are organometal fungicides, which are widely used for the control of diseases in plants. Female Wistar rats were exposed orally to 200 and 400 ppm propineb and 250 ppm maneb, from the sixth day of gestation up to birth. We found that the body weights of both one-day old litters and their fungicide-treated mothers were lower than those of controls. Histological examination of the kidneys of fetus and fungicide-treated pregnant females showed a variety of histopathological effects. Moreover, the analysis of zinc (Zn) and manganese (Mn) concentrations (using inductively coupled plasma-atomic emission spectrometry) in the kidneys of pregnant females exposed to organometallic fungicides during pregnancy demonstrated that the metal concentrations in the kidney were higher than those of controls. However, the renal metal concentrations were significantly increased in the litters subjected to the fungicides during gestation, indicating that high levels of the trace metals in the organ of fetus may well be due to the fungicides easily passing the placental barrier.


Surgery Today | 2003

Diagnostic delay increases morbidity in children with gastrointestinal perforation from blunt abdominal trauma

Hayrettin Öztürk; Abdurrahman Onen; Selcuk Otcu; Ali Ihsan Dokucu; Yusuf Yagmur; Mete Kaya; Selçuk Yücesan

Abstract.Purpose: Intestinal perforation due to blunt abdominal trauma is rarely seen in children and delayed diagnosis is a major concern. Because the potential risk factors affecting morbidity are not well known, we evaluated whether diagnostic delay increases morbidity in gastrointestinal perforation from blunt abdominal trauma in children. Methods: Twenty-nine children with gastrointestinal perforation caused by blunt abdominal trauma, admitted to our clinic between 1983 and 2001, were retrospectively evaluated by analyzing the relationship between overall morbidity and potential risk factors. Results: There were 23 boys and 6 girls. Most of the injuries were caused by falls and motor vehicle accidents. The jejunum was the most frequent site of perforation followed by the ileum. Simple closure was the most common surgical procedure. Postoperative complications developed in five patients (17%) and included wound infections in two, wound dehiscence in one, and adhesive small bowel obstruction in two. Potential risk factors such as trauma mechanism, the presence of shock on admission, and associated organ injury were not significantly correlated with postoperative complications, whereas a period of delay exceeding 8 h and an Injury Severity Score (ISS) exceeding 15 were significantly related to septic complications (P < 0.05). The relative risk of a septic complication developing was higher than 2 for the following risk factors: a fall from a flat-roofed house and a time delay before operative intervention. There were three deaths (10%) in this series, caused by sepsis in two patients and head injury in one. Conclusion: These findings suggest that rapid diagnosis and treatment is important for preventing complications in patients with intestinal perforation caused by blunt abdominal trauma. A delay exceeding 8 h and an ISS score exceeding 15 were related to significant septic complications, and falls from flat-roofed houses are an important public safety risk in Turkey.


Journal of Pediatric Urology | 2007

Treatment and outcome of prenatally detected newborn hydronephrosis

Abdurrahman Onen

OBJECTIVE For neonates with antenatally diagnosed primary ureteropelvic junction (UPJ)-type hydronephrosis, to attempt to clarify and refine criteria for establishing optimal follow-up and treatment guidelines. PATIENTS AND METHODS A total of 162 newborns (228 hydronephrotic kidneys) with this condition were prospectively followed and treated by the same surgeon in 2001-2005 for a mean of 53 (13-72) months. Ultrasonography and diuretic renogram were used for diagnosis and follow up, and Onens grading system to determine degree of hydronephrosis. RESULTS On first postnatal ultrasound, the severity of hydronephrosis was grade 1 in 152 kidneys (surgery, 0%), 2 in 41 (surgery, 19.5%), 3 in 19 (surgery, 42.1%), and 4 in 16 kidneys (surgery, 93.8%). All the grade 1 cases resolved spontaneously without renal deterioration (renal function >40%). Renal function ranged between 7% and 34% in grade 4 patients. Overall, 201 hydronephrotic kidneys (88.2%) resolved spontaneously, while 27 (11.8%) required pyeloplasty because of evidence of obstructive injury, including increased hydronephrosis in 14/27 (6/27 had less than 10% decrease in renal function), greater than 10% decrease of renal function in 9/27, and greater than 10% decrease of renal function as well as increased hydronephrosis in 4/27 patients (15%). CONCLUSION In most cases, neonatal hydronephrosis is a relatively benign condition that can be followed safely by an initial non-operative approach unless there is evidence of obstructive injury. A follow-up protocol that permits early identification of a limited number of kidneys that may develop signs of obstruction and require pyeloplasty is crucial for a favorable outcome in patients with primary UPJ-type hydronephrosis. Onens hydronephrosis grading system promises an easier and more appropriate follow up and timely treatment for children with this condition. A sufficient follow-up interval, especially during the first 3 years of life, is essential to help prevent permanent loss of renal function in kidneys that do develop signs of obstruction.


Surgery Today | 2011

Nonoperative Management of Pancreatic Injuries in Pediatric Patients

Murat Kemal Cigdem; Senem Senturk; Abdurrahman Onen; Mesut Siga; Hatice Akay; Selcuk Otcu

PurposeNonoperative management of minor pancreatic injury is the generally accepted approach. However, the management of major pancreatic injury remains controversial in pediatric patients. The aim of the present study was to determine the safety and efficacy of nonoperative management of pancreatic injury in pediatric patients.MethodsBetween 2003 and 2009, 31 patients, 28 male and 3 female, with pancreatic injury due to blunt abdominal trauma were treated in our clinic. All patients were evaluated by ultrasonography, computed tomography (CT), and evaluation of serum amylase levels. Patients with ongoing hemodynamic instability after resuscitation or signs of bowel perforation underwent immediate laparotomy, and the remaining patients were conservatively treated. Conservative treatment consisted of nasogastric tube replacement, total parenteral nutrition, monitoring of amylase levels, and serial clinical examination.ResultsThe most common mechanism of injury was a fall (35.4%). Ten patients (32.2%) had associated extraabdominal injuries, and 18 patients (58.1%) had associated abdominal injuries. The spleen was the most common site of intra-abdominal injury that was associated with pancreatic trauma. Initial amylase levels were normal in 5 patients, whose CT scans revealed pancreatic injury. Twenty-five patients (80.6%) were conservatively treated. Six patients (19.4%) required surgical intervention because of a hollow viscus or diaphragmatic injury and hemodynamic instability. A pseudocyst developed in 11 of the 25 patients who were nonoperatively treated; 6 patients required intervention for the pseudocyst (percutaneous drainage and cystogastrostomy). No patient succumbed to injury.ConclusionsThe majority of the pancreatic injuries in pediatric patients can be successfully treated conservatively, unless there is hemodynamic instability and a hollow viscus injury. The most common complication is a pseudocyst.


Journal of Pediatric Surgery | 2003

Effects of whole blood, crystalloid, and colloid resuscitation of hemorrhagic shock on renal damage in rats: an ultrastructural study.

Abdurrahman Onen; Murat Kemal Cigdem; Engin Deveci; Sedat Kaya; Selim Turhanoglu; Mehmet Yaldiz

PURPOSE The aim of this study was to determine the effects of whole blood, crystalloid, and colloid treatment on histopathologic damage of kidney induced by hemorrhagic shock in rats. METHODS Fifty-six male Sprague Dawley rats were divided into 8 groups. The carotid artery was cannulated, and systolic arterial pressure (SAP), diastolic arterial pressure (DAP), heart rate (HR), and rectal temperature (RT) were observed during the procedure. The jugular vein also was cannulated, and the SAP was decreased by aspiration of 75% of blood through the jugular vein in the control (nonresuscitated) and study (resuscitated) groups, whereas blood was not diminished in the sham group. The hemorrhagic shock was permitted to last 45 minutes; then, the study group rats were resuscitated with heparinized shed autologous whole blood (WB), normal saline (NS), Lactated Ringers solution (LR), hydroxyethyl starch 6% (HES6), hydroxyethyl starch 10% (HES10), or dextran 40 (D40). Histopathologic evaluation was performed under light and electron microscope. RESULTS The RT, SAP, and DAP decreased, and HR increased significantly in the control and study groups during the shock period compared with those of sham group. After volume resuscitation, these parameters changed to preshock levels. Electron and light microscopic examinations of kidneys showed severe proximal tubular degeneration with moderate glomerular damage in the control group; moderate proximal tubular degeneration with mild glomerular damage in the NS, LR, HES6, and HES10 groups; and mild proximal tubular degeneration with no evidence of glomerular damage in the WB and D-40 groups. CONCLUSIONS The characteristic ultrastructural features of hemorrhagic shock appear to be severe tubular degeneration and mild to moderate changes in glomeruli. Resuscitation of hemorrhagic shock with whole blood or dextran 40 solution appears to be most favorable therapy in preventing ultrastructural renal damage in rats.


BJUI | 2002

Blunt renal trauma in children with previously undiagnosed pre‐existing renal lesions and guidelines for effective initial management of kidney injury

Abdurrahman Onen; Mete Kaya; M.K. Ciǧdem; Selcuk Otcu; Hayrettin Öztürk; Ali Ihsan Dokucu

Objectives To record pre‐existing renal lesions (PERL) found incidentally during evaluation for blunt renal trauma in children, determine their importance, suggest guidelines for the effective initial management of children with significant renal trauma and to evaluate the role of temporary percutaneous nephrostomy tube drainage (TPND) in these patients.

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