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Papagiannis J.,Mitera Childrens Hospital | Papadopoulou K.,Papageorgiou General Hospital | Rammos S.,Onassis Cardiac Surgery Center | Katritsis D.,Athens Euroclinic
Hellenic Journal of Cardiology | Year: 2010

Introduction: Cryoablation is used increasingly for the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). We sought to compare the long-term outcomes of cryoablation (Cryo) vs. radiofrequency (RF) ablation for the treatment of AVNRT in children. Methods: Two groups of consecutive patients were analyzed retrospectively: the RF group, 20 patients (60% males, mean age 13.25 ± 2.59 years), and the Cryo group, 20 patients (55% males, mean age 12.17 ± 3.07 years). Follow up was 52.7 ± 16.5 months for the RF and 32.8 ± 11.9 months for the Cryo group. Results: Acute success rates (100% for RF vs. 90% for Cryo), procedural times (147.75 ± 37.15 min for RF vs. 184.4 ± 75.59 min for Cryo), and fluoroscopy times (10.9 ± 6.46 min for RF vs. 6.41 ± 6.92 min for Cryo) were not statistically significantly different between the two groups. The number of lesions was significantly higher in RF than in Cryo (8.85 ± 6.63 vs. 3.6 ± 1.9, p=0.007). Transient AV block during ablation occurred in 1 patient in each group. No permanent AV block was observed. Recurrence rate was 10% in the RF and 27.7% in the Cryo group (p=0.222) occurring up to 14 months after the procedure. Conclusion: Cryoablation is safe and effective for the treatment of AVNRT in pediatric patients, but there is a tendency for higher recurrence rates compared to radiofrequency ablation. Techniques to reduce recurrence rates after cryoablation are needed.


Sgouros S.,Mitera Childrens Hospital | Sgouros S.,National and Kapodistrian University of Athens
Child's Nervous System | Year: 2013

In the last decade there have been significant improvements in all the fields of management of patients with spinal dysraphism, which have increased dramatically the quality of life of these children. Prevention of spina bifida with food fortification is becoming increasingly practiced worldwide. As result, in many parts of the world the frequency of myelomeningocele has decreased. Intrauterine closure of myelomeningocele has been attempted in many institutions with variable results. While it is still at the sphere of experimental therapy, it is reasonable to anticipate progress in this field in the next decade. Antenatal MR imaging is already providing very high level of detail even before the child is born. This creates new ethical dilemmas and requires additional care, but has improved significantly the overall management of patients and their families. Further improvements are anticipated in this field. Management of neuropathic bladder has improved significantly in the last decade and is anticipated to play an increasing role in the long term follow up. Surgery for spinal cord tethering in all its forms has improved in the last decade, with far more chances of complete untethering now in comparison to 10-15 years ago, with the use of micro-neurosurgical techniques and intraoperative monitoring. It is reasonable to expect that in the next decade, intraoperative neurophysiological monitoring during spinal cord surgery will become mandatory. In the 2013 Annual Special Issue we have assembled a team of authors distinguished in their fields, who bring us up to date with all the latest developments. © 2013 Springer-Verlag Berlin Heidelberg.


Tsitouras V.,Mitera Childrens Hospital | Sgouros S.,Mitera Childrens Hospital | Sgouros S.,National and Kapodistrian University of Athens
Child's Nervous System | Year: 2013

Introduction: The presence of syringomyelia varies in patients with different forms of dysraphism; from 21 % to 67 %. Only around 60 % of patients with syringomyelia is likely to experience symptoms related to it. Pathophysiology: Many theories have been outlined for the creation of syringomyelia. The one most applicable to tethered cord dictates that tensile radial stress may create a syrinx in a previously normal cord tissue and transiently lower pressure may draw in interstitial fluid, causing the syrinx to enlarge if fluid exit is inhibited. In addition, arachnoiditis increases flow resistance in the spinal subarachnoid space, altering temporal CSF pulse pressure dynamics, which promotes entry of CSF in to the spinal cord. Clinical presentation: There is a significant overlap between the symptoms that are due to tethered cord and syringomyelia, both in newly presenting patients with coexisting syringomyelia, and in previously treated patients who during follow-up present recurrent symptoms and a new syringomyelia cavity. Treatment: The treatment of patients with tethered cord and syringomyelia is directed towards untethering the cord from its most caudal region upwards and restoring spinal anatomy with reestablishment of unobstructed CSF flow in the subarachnoid space. Only if complete untethering has been ensured and syringomyelia deteriorates, then surgical treatment can be directed against the syrinx. In patients with spinal dysraphism and coexisting hydrocephalus, radiological presentation of new syringomyelia or deterioration of previously known syringomyelia may signify shunt obstruction "until proven otherwise". Conclusion: In most occasions, satisfactory cord untethering addresses the development of syringomyelia. © 2013 Springer-Verlag Berlin Heidelberg.


Tsitouras V.,Mitera Childrens Hospital | Sgouros S.,Mitera Childrens Hospital | Sgouros S.,National and Kapodistrian University of Athens
Child's Nervous System | Year: 2011

Introduction: Intraventricular/germinal matrix hemorrhage affects 7-30% of premature neonates, 25-80% of whom (depending on the grade of the hemorrhage) will develop hydrocephalus requiring shunting. Predisposing factors are low birth weight and gestational age. Material: There is increasing evidence for the role of TGF-β1 in the pathogenesis of hydrocephalus, but attempts to develop treatment modalities to clear the cerebrospinal fluid (CSF) from blood degradation products have not succeeded so far. Ultrasound is a valuable screening tool for high-risk infants and magnetic resonance imaging is increasingly utilized to differentiate progressive hydrocephalus from ex vacuo ventriculomegaly, evaluate periventricular parenchymal damage, decide on the surgical treatment of hydrocephalus, and follow up these patients in the long term. Treatment of increasing ventriculomegaly and intracranial hypertension in the presence of hemorrhagic CSF can involve a variety of strategies, all with relative drawbacks, aiming to drain the CSF while gaining time for it to clear and the neonate to reach term and become a suitable candidate for shunting. Eventually, patients with progressive ventriculomegaly causing intracranial hypertension, who have reached term and their CSF has cleared from blood products, will need shunting. Conclusion: Cognitive long-term outcome is influenced more by the effect of the initial hemorrhage and other perinatal events and less by hydrocephalus, provided that this has been addressed timely in the early postnatal period. Shunting can have many long-term side effects due to mechanical complications and overdrainage. In particular, patients with posthemorrhagic hydrocephalus are more susceptible to multiloculated hydrocephalus and encysted fourth ventricle, both of which are challenging to treat. © 2011 Springer-Verlag.


Constantini S.,Dana Childrens Hospital | Sgouros S.,Mitera Childrens Hospital | Kulkarni A.,Hospital for Sick Children
World Neurosurgery | Year: 2013

Objectives: The aim of this report is to review current data on the role of neuroendoscopy in infants. Specific emphasis will be given to the International Infant Hydrocephalus Study (IIHS). Previous studies, available information, and future directions are discussed. Methods: The IIHS is a major international endeavor comparing the results of endoscopic third ventriculostomy (ETV) to ventriculoperitoneal shunting in infants younger than 2 years of age. It is a prospective, randomized study, with a "parental preference" option, that recruits infants with aqueductal stenosis without a history of prematurity or other associated brain anomalies. The primary outcome measure is neurocognitive outcome at 5 years of age. In addition to IIHS data, we also looked at results of neuroendoscopy in infants with other indications, such as fourth ventricular outlet obstruction, Dandy Walker syndrome, etc. Results: The IIHS study includes more than 40 centers on all continents. To date, we have recruited more than 150 infants to the study. At this point we can only release limited data, namely that the complication rates are similar between the two arms. More patients are needed to finalize the study, with an endpoint of 250 children. Conclusions: Neuroendoscopy in infants can be performed with reasonable morbidity. The preferred indications in infants are still not totally refined, especially vis-a-vis shunting procedures. More international, multicenter efforts are required to clarify these points. © 2013 Elsevier Inc. All rights reserved.


Papagiannis J.,Mitera Childrens Hospital | Avramidis D.,Mitera Childrens Hospital | Alexopoulos C.,Mitera Childrens Hospital | Kirvassilis G.,Mitera Childrens Hospital
PACE - Pacing and Clinical Electrophysiology | Year: 2011

Background: We sought to assess the impact of routine use of a nonfluoroscopic navigation system in the procedural aspects of radiofrequency ablation of accessory pathways (APs) in pediatric and congenital heart disease (CHD) patients and the reduction of fluoroscopy in different pathway locations. Methods: This was a retrospective review of 192 patients, divided in two groups: group A (76 patients, fluoroscopic only ablation) and group B (116 patients, combined use of fluoroscopy and a nonfluoroscopic system (NavX™). Comparison of procedural aspects (procedure time, fluoroscopy time, success, complications, and recurrences) was performed. Results: The two groups were comparable in terms of age, AP location, and presence of CHD. The mean age was 11.34 ± 4.65 years in group A versus 10.91 ± 3.68 years in group B. The procedure duration was significantly shorter in group B than in group A (177.06 ± 62.18 vs 242.45 ± 99.07) (P < 0.001). There was a significant reduction in the fluoroscopy time in group B compared to group A (8.27 ± 8.23 vs 39.77 ± 32.65 minutes) (P < 0.001). The difference between the two groups was statistically significant in all categories of APs. The success rate was 97.4% in group A and 96.6% in group B. There were no complications directly related to the use of the nonfluoroscopic system. There was no difference in the recurrence rate. Conclusions: The use of a nonfluoroscopic system for catheter navigation resulted in significant reduction of total procedure and fluoroscopy time during catheter ablation of APs in pediatric and CHD patients, regardless of the location of the pathway, without a compromise in safety and efficacy. © 2011 Wiley Periodicals, Inc.


Charalambides C.,MITERA Childrens Hospital | Sgouros S.,MITERA Childrens Hospital
Pediatric Neurosurgery | Year: 2013

Ventriculoperitoneal shunt malfunction is a relatively common problem encountered in shunted hydrocephalic patients and is attributed most frequently to mechanical obstruction of the ventricular catheter. We present the case of a rare cause of mechanical obstruction of the peritoneal catheter due to the spontaneous formation of a knot just underneath the abdominal wound. This occurred 1 year after shunt implantation and is thought to have been caused by a combination of plastic material memory and bowel peristaltic movements. This case brings for discussion the role of radiographic investigation of the shunt system in children who present with suspected shunt obstruction. Radiographic investigation is warranted in children who have unusual shunt arrangements (e.g. Y-connectors and multiple catheters) in order to exclude disconnections or those who develop shunt problems years after implantation, to exclude material fracture in the neck or migration of any kind. In shunt systems which have been implanted for shorter time periods, the need for radiographs is less apparent. Some surgeons proclaim that when clinical circumstances fall outside the realms of obvious possible proximal obstruction, radiographic evaluation of the shunt system should be considered. Copyright © 2013 S. Karger AG, Basel.


Branch pulmonary artery stenosis may occur in 4%-28% of patients after an arterial switch operation. Balloon dilation can be attempted with variable results, while stenting is a more definitive option when balloon dilation fails. We report the case of a young boy who underwent balloon dilation of a stenosed left pulmonary artery 9 years after an arterial switch operation and was noted to have an aortopulmonary window about a year later. This was treated with covered stent implantation, which dealt both with the aortopulmonary window and the residual stenosis. The diagnostic process with cardiac magnetic resonance imaging and cardiac catheterization of such an unusual entity as well as the transcatheter management are discussed in detail.


Pitsika M.,Mitera Childrens Hospital | Tsitouras V.,Mitera Childrens Hospital
Journal of Neurosurgery: Pediatrics | Year: 2013

Mutism of cerebellar origin is a well-described clinical entity that complicates operations for posterior fossa tumors, especially in children. This review focuses on the current understanding of principal pathophysiological aspects and risk factors, epidemiology, clinical characteristics, treatment strategies, and outcome considerations. The PubMed database was searched using the term cerebellar mutism and relevant definitions to identify publications in the English-language literature. Pertinent publications were selected from the reference lists of the previously identified articles. Over the last few years an increasing number of prospective studies and reviews have provided valuable information regarding the cerebellar mutism syndrome. Importantly, the clarification of principal terminology that surrounds the wide clinical spectrum of the syndrome results in more focused research and more effective identification of this entity. In children who undergo surgery for medulloblastoma the incidence of cerebellar mutism syndrome was reported to be 24%, and significant risk factors so far are brainstem involvement and midline location of the tumor. The dentate-thalamo-cortical tracts and lesions that affect their integrity are considered significant pathophysiological issues, especially the tract that originates in the right cerebellar hemisphere. Moderate and severe forms of the cerebellar mutism syndrome are the most frequent types during the initial presentation, and the overall neurocognitive outcome is not as favorable as thought in the earlier publications. Advanced neuroimaging techniques could contribute to identification of high-risk patients preoperatively and allow for more effective surgical planning that should focus on maximal tumor resection with minimal risk to important neural structures. Properly designed multicenter trials are needed to provide stronger evidence regarding effective prevention of cerebellar mutism and the best therapeutic approaches for such patients with a combination of pharmacological agents and multidisciplinary speech and behavior augmentation. ©AANS, 2013.


Tzifa A.,Mitera Childrens Hospital | Momenah T.,Prince Salman Heart Center | Al Sahari A.,Prince Salman Heart Center | Al Khalaf K.,Prince Salman Heart Center | And 2 more authors.
EuroIntervention | Year: 2014

Aims: Transcatheter implantation of valved stents (Melody and Edwards valves) for replacement of the pulmonary valve is currently an established procedure. We reviewed our experience on implantation of such valves in the tricuspid valve position. Methods and results: Transcatheter valve implantation in the tricuspid position was attempted in five patients. Four patients had predominantly tricuspid valve regurgitation, two of whom also had tricuspid valve stenosis. All patients had severely symptomatic right heart failure. Patient median age and weight were 12 years and 50 kg (range six-43 years and 13-68 kg, respectively). All patients had a bioprosthetic valve already in place. The mean gradient across the tricuspid valve decreased from 12 to 3 mmHg after the procedure. Median procedure time and fluoroscopy time were 100 and 39 min (range 60-180 and 30-57 min, respectively). The patients' functional class improved from NYHA Class III to II in three and from Class III to I in two patients during a followup period of 15-22 months. Conclusions: Transcatheter replacement of malfunctioning bioprosthetic valves in the tricuspid position using valved stents is an attractive alternative to repeat surgery in hig-hrisk or multioperated patients. Longer follow-up and a larger number of patients are required to establish the long-term benefit of the procedure and freedom from reinterventions.

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