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Biomedical subjects

D Renier

Publications and source records attributed to D Renier.

At least 55 records · Page 3Linked to original sources
PubMed1998

Non-invasive aortic blood flow measurement in infants during repair of craniosynostosis.

We have assessed the potential clinical benefit of a new echo-Doppler device (Dynemo 3000) which provides a continuous measure of aortic blood flow (ABF) using an aortic flowmeter and a paediatric oesophageal probe, during repair of craniosynostosis in infants under general anaesthesia. The data recorded included: ABFi (i = indexed to body surface area), stroke volume (SVi), systemic vascular resistance (TSVRi), pre-ejection period (PEP), left ventricular ejection time (LVET), mean arterial pressure (MAP), heart rate (HR) and central venous pressure (CVP). Data were collected: before (T1) and 3 min after skin incision (T2), at the time of maximal haemorrhage (T3) and at the end of the procedure (T4). Twelve infants (aged 7.0 (range 6-12) months) were included. ABFi, MAP and CVP were significantly lower at T3 compared with T1 (2.0 (0.8) vs 3.0 (0.8) litre min-1 m-2, 46.1 (5.8) vs 65.2 (8.9) mm Hg and 2.8 (1.6) vs 5.2 (2.1) mm Hg; P < 0.05). PEP/LVET ratio was significantly lower at T2 compared with T1 (0.25 (0.05) vs 0.30 (0.06)) and increased at T4 (0.36 (0.04); P < 0.05). These preliminary results suggest that this non-invasive ABF echo-Doppler device may be useful for continuous haemodynamic monitoring during a surgical procedure associated with haemorrhage in infants.

Anesthesia, General↗
PubMed1998

Occipital remodeling and suboccipital decompression in severe craniosynostosis associated with tonsillar herniation.

OBJECTIVE: The goal was to describe a surgical technique allowing occipital vault remodeling and suboccipital decompression in patients affected by multiple-suture synostosis presenting severe occipital flattening and chronic tonsillar herniation (CTH). METHODS: Four patients (two with Crouzon's syndrome, one with Kleeblattschädel, and one with complex craniosynostosis) presenting multiple-suture synostosis with severe occipital flattening, posterior fingerprint impressions, and CTH were operated on in the prone position. For three patients, occipital vault remodeling and suboccipital decompression without dural opening were performed; for one patient affected by Kleeblattschädel, an upper cervical laminectomy and dural opening were performed. All patients were studied with magnetic resonance imaging pre- and postoperatively. RESULTS: No complications were observed. In all cases, postoperative magnetic resonance imaging revealed good decompression of the craniocervical junction, with resolution of brain stem displacement. In one case, CTH recurred 15 months after surgery, although in a less severe form. CONCLUSION: In selected cases of complex or syndromic craniosynostosis with predominant posterior deformity and CTH, this technique was safe and useful in the management of cranial reconstruction, allowing posterior vault remodeling and prophylactic suboccipital decompression. After validation with a larger number of patients, it could prove to be a useful option in all cases of complex craniosynostosis with CTH in which a staged repair of the craniosynostosis is to be considered.

Cerebellar Diseases↗
PubMed1998

Hydrocephalus and craniosynostosis.

OBJECT: A retrospective study of 1727 cases of craniosynostosis was undertaken to determine the interrelationship between abnormal cerebrospinal fluid (CSF) hydrodynamics and craniosynostosis. METHODS: The patients were divided into two groups: nonsyndromic craniosynostosis and syndromic craniosynostosis. Cases of occipital plagiocephaly without suture synostosis and cases of shunt-induced craniosynostosis were excluded from the study. The majority of patients (1297) were treated surgically for their cranial deformity; 95% of these patients had a postoperative follow-up review period lasting 5 years. Clinical and radiographic charts covering the time from presentation through the follow-up period were reviewed. CONCLUSIONS: Abnormal intracranial CSF hydrodynamics was found in 8.1% of the patients (3.4% of whom had received shunts and 4.5% of whom had not). Three types of CSF hydrodynamic disturbance were observed: progressive hydrocephalus with ventricular dilation, nonprogressive ventriculomegaly, and dilation of the subarachnoid spaces. Hydrocephalus occurred much more frequently in patients with syndromic craniosynostosis (12.1%) than in those with isolated craniosynostosis (0.3%). In fact, patients with kleeblattschädel exhibited hydrocephalus as a constant feature and patients with Crouzon's syndrome were far more likely to have hydrocephalus than those with other syndromes. In Apert's syndrome, ventricular dilation occurred very frequently, but it was almost always nonprogressive in nature. In most cases of syndromic craniosynostosis, venous sinus obstruction and/or chronic tonsillar herniation were found. Their role in the pathophysiology of hydrocephalus in craniosynostosis is discussed.

Acrocephalosyndactylia↗
PubMed1998

Papillomas and carcinomas of the choroid plexus in children.

OBJECT: Choroid plexus tumors are rare intraventricular tumors (1% of all intracranial tumors) that occur mainly in children. The pathophysiological characteristics of associated hydrocephalus, surgical management, and oncological issues related to these tumors remain a matter of debate. To understand more about these tumors, the authors have reviewed their experience with the management of 38 children with choroid plexus tumors. METHODS: There were 25 cases of papilloma and 13 of carcinoma. The mean age of the patients at presentation was 22.5 months, and one-half of the patients were younger than 2 years of age. Hydrocephalus was present in 33 patients and poorly correlated with the size, site, and pathological characteristics of the tumor. In nine children, a ventriculoperitoneal shunt was required after tumor excision, calling into question the notion that cerebrospinal fluid oversecretion is the only cause of hydrocephalus. Complete excision was achieved in 96% of the cases of papilloma and 61.5% of the cases of carcinoma. These surgical procedures were complicated by the risks of intraoperative hemorrhage, which proved to be fatal in two cases, and postoperative brain collapse, which led to subdural fluid collections requiring subdural shunt placement in six patients. Preoperative embolization was partially successful in four cases and significantly assisted surgery. Preoperative controlled drainage of excessively dilated ventricles and intraoperative gluing of the cortical incision have been used to address the problem of postoperative brain collapse. Patients with carcinomas were treated postoperatively by chemotherapy alone (seven cases), radiotherapy (one case), or chemotherapy plus radiotherapy (one case). The overall 5-year survival rate was 100% for patients with papillomas and 40% for those with carcinomas. CONCLUSIONS: Total surgical excision is curative in cases of papillomas. For carcinomas, the most effective treatment remains total surgical excision; however, adjuvant treatment in the form of chemotherapy in patients younger than age 3 years, supplemented by radiation therapy in older children, can moderately reduce the risk of recurrence.

Adolescent↗
PubMed1998

Functional outcome after surgery for trigonocephaly.

The long-term mental outcome of 76 children operated on for trigonocephaly was assessed, and the factors influencing the prognosis were studied. Final assessment of mental development was made on children who were more than 3 years old and was based on the occurrence of behavioral disturbances, learning disability, and school difficulties, and on intellectual efficiency. Children were graded into three groups: no abnormality, mild abnormalities but with normal social function, and grossly abnormal. Preoperative computed tomography scans were used to measure the severity of the frontal stenosis and to identify associated intracranial abnormalities, such as agenesis of the corpus callosum, dilatation of the subdural spaces, or hydrocephalus. Associated extracranial malformations and associated family cases were also noted. Lastly, the family setting was studied. Overall, 31.6 percent of patients had evidence of some degree of trouble. Several correlations were identified: mental development was worse when the frontal stenosis was severe, when cranial reconstruction was performed after 1 year of age, and when there were associated extracranial malformations. In addition, the family environment was found to have a major influence, but the presence of intracranial abnormalities did not correlate with mental development.

Adolescent↗
PubMed1998

[Aplasia of the skull without scalp anomalies. A case report].

The authors report an extremely rare case of cranio-facial anomaly, which, to our knowledge has previously been reported only once (1993, Chakraborty and al.). This male infant presented with a giant congenital bone defect of the skull in the vertex region (10 x 20 cm) with no scalp deficiency. Minimal turricephaly and moderate telorbitism were associated with minor limb anomalies, but psychometric assessment appeared normal. Non-surgical follow-up was initially decided, but spontaneous reossification was so moderate that skull reconstruction was decided at 28 months of age, because of traumatological risks. A full-size resin cephalic skeletal reconstruction was obtained by 3D computerized tomography utilizing stereolithography techniques. A titanium plate was customized on the resin model for ideal adaptation to the convex skull defect (8 x 16 cm). Surgery was simply performed, consisting of preliminary undermining between the dura mater and scalp, and screwing of the custom titanium plate. The initial follow-up was uneventful.

Bone Plates↗
PubMed1997

Antley-Bixler syndrome. Description of two new cases and a review of the literature.

Antley-Bixler syndrome was first described in 1975, and to date 20 cases have been reported. In addition to brachycephaly, the syndrome is associated with midface hypoplasia, often with choanal stenosis or atresia, bilateral radiohumeral synostosis, multiple joint contractures, femoral bowing and long bone fractures, "pear-shaped" nose, dysplastic ears and, occasionally, urogenital or cardiac defects. Survival is closely linked to upper airway obstruction. This, in addition to craniosynostosis, also affects mental prognosis. The cluster of malformations and their severity are variable, and while numerous children have died early from respiratory distress, one third of them are alive and have had quite satisfactory development. With early and effective prevention of respiratory complications and early treatment of craniosynostosis, the overall prognosis can be favorable. The mode of inheritance is probably autosomal recessive, and midtrimester prenatal diagnosis is feasible. Genetic counseling depends on accurate prognostic and therapeutic data. We describe two new cases, a 4-year-old boy with unilateral coronal synostosis and radiohumeral synostosis on the same side and an 18-month-old girl with brachycephaly and imperforate anus.

Abnormalities, Multiple↗
PubMed1997

Congenital lumbosacral lipomas.

Congenital lumbosacral lipomas can be responsible for progressive defects. The general feeling is that tethering of roots, filum, or cord probably explains this evolution, and that untethering of these structures could prevent late deterioration. Like the vast majority of neurosurgeons, we too have routinely and systematically operated on lumbosacral lipomas, even in the absence of neurological deficits. This policy stemmed from our belief that spontaneous neurological deterioration was frequent, recovery from preoperative deficits rare, and surgery both efficient and benign in nature. After 22 years of experience, we felt that it was necessary to review our series of 291 lipomas (38 lipomas of the filum and 253 of the conus) operated on from 1972 to 1994. To reassess the value of prophylactic surgery, we attempted an accurate evaluation of (1) the risk of pathology, (2) the risks involved in surgery, (3) the postoperative outcome with respect to preoperative deficits, and (4) the postoperative outcome in asymptomatic patients at 1 year and at maximum follow-up. Special attention was paid to 93 patients whose postoperative follow-up was more than 5 years (average 8.7, median 8, range 5-23 years). Of these 93 patients, 39 were asymptomatic preoperatively (7 with lipoma of the filum and 32 with lipoma of the conus). Lipomas of the filum and of the conus are entirely different lesions and were studied separately. In 6 cases prenatal diagnosis had been possible. The mean age at surgery was 6.4 years. Low back skin stigmata were present in 89.4% of cases. Preoperative neurological deficits existed in 57% of the patients and were congenital in 22%. Clinical signs and symptoms recorded were pain in 13.3% of the patients and/or neurological deficits affecting sphincter (52%), motor (27.6%) and sensory (22.4%) functions. Deficits were progressive in 22.4% of cases, slowly progressive in 58.8% of these and rapidly progressive in the remaining 41.2%. In 36 patients (13.2%) the lipomas were seen to grow either subcutaneously or intraspinally. Among these patients, 21 were infants, 2 were obese adolescents, and 10 were pregnant women. The metabolism of the fat within the lipomas was studied in 11 patients and found to be similar to that at other sites. Lipomas were associated with various other malformations, either intra- or extraspinal. These associated anomalies were rare in the case of lipomatous filum (5.2%) but frequent with lipomas of the conus, except for intracranial malformations (3.6%). Therapeutic objectives were spinal cord untethering and decompression, sparing of functional neural tissue and prevention of retethering. Procedures used to achieve these goals were subtotal removal of the lipoma, intraoperative monitoring, duroplasty, and sometimes closure of the placode. Histologically, lipomas consisted of normal mature fat. However, 77% of them also included a wide variety of other tissues, originating from ectoderm, mesoderm, or entoderm. This indicates that lipomas are either simple or complex teratomas. The results of the study are as follows. (1) Surgery was easy and safe when performed for treatment of lipomas of the filum (no complications), but difficult and hazardous in the case of lipomas of the conus (20% local, 3.9% neurological complications). (2) All types of deficit could be improved by surgery, which was beneficial in all cases of lipoma of the filum and 50% of cases of lipoma of the conus. (3) In asymptomatic patients long-term surgical results depended on the anatomical type of the lipoma. They were excellent in lipomas of the filum. In lipomas of the conus they were good in the short term but eroded with time. At more than 5 years of follow-up only 53.1% of the patients were still free of symptoms. (4) Reoperations were performed in 16 patients (5.5%), 5 (31.2%) of whom improved postoperatively, while in 7 (43.7%) progression stopped, in 3 (18.7%) deterioration continued and in 1 (6.2%) the condition was wor

Adolescent↗
PubMed1997

[Anesthesia and intensive care of craniostenosis and craniofacial dysmorphism in children].

Craniosynostosis occurs in one out of 2,000 births. It results in primary skull deformations requiring surgical repair, in infants with a body weight of less than 10 kg. Pure craniosynostosis is the most frequent situation, where the risk for cerebral compression during brain development is the lowest. Therefore the aim of surgical correction in this case is mainly cosmetic. Conversely, in syndromic craniosynostosis, associated malformations are more common and cerebral, visual and respiratory consequences of complex facio-craniosynostosis are usually severe. Current surgical techniques consist of a total skull vault reconstruction which carry a high risk of sudden and major blood losses. Intraoperatively, whatever the type of craniosynostosis, mean blood losses corresponding to 90% of estimated red cell mass have to be anticipated. These blood losses vary according to the type of skull deformation and the type of surgery. Accurate evaluation is usually difficult and must be based more on calculation of red cell mass variations than on simple monitoring of surgical drainage. Invasive haemodynamic monitoring is always required. To reduce the amount of homologous blood transfusion, peroperative haemodilution seems to be the most suitable technique, due to unresolved technical difficulties in autotransfusion practice in infants. Severe facial deformities are associated with chronic hypoxaemia and cerebral compression representing major risk for these children in poor condition undergoing such major surgical procedures. With experienced teams, this high-risk surgery carries a low peroperative mortality (less than 1%) and morbidity rate. The latter includes essentially transient peroperative hypotension. The excellent final cosmetic and functional results justify the practice of this surgery in children with a bodyweight of less than 10 kg.

Anesthesia, General↗
PubMed1997

[Oxycephaly, a severe craniosynostosis. Apropos of a series of 129 cases].

AIMS: The authors analyse a series of patients with oxycephaly in order to detail the definition of this craniosynostosis and its functional prognosis. PATIENTS AND METHODS: The medical records of 129 oxycephalic patients were reviewed. Skull X-rays, ophthalmologic examination, mental level assessment, intracranial pressure monitoring and CT scan were analysed. The more recent patients were also analysed by MRI. Operated on or not, the patients were followed-up, particularly as far as the mental evolution is concerned. Mean follow-up was 3 years 7 months. RESULTS: One third of the patients came from North Africa, where oxycephaly seems predominant. Mean age at diagnosis was 6 years. Past history of rickets was found in 15% of the patients. On X-rays, the vast majority of the patients presented with multisutural synostosis involving both coronal and sagittal sutures, and diffuse digital prints. At the first mental assessment, one third of the patients had an IQ below 80. Papilledema was found in 17%. The monitoring of intracranial pressure showed an increased pressure in almost two thirds of the patients. Sixty-four percent of the patients with increased intracranial pressure had a normal fundoscopy. Out of 16 patients explored by MRI, 12 had a Chiari I malformation. Postoperatively, all papilledemas disappeared, and the intracranial pressure returned to normal in all cases with preoperative increased intracranial pressure. The mental level seemed to stabilize, the mean postoperative IQ being strongly correlated with the preoperative level. In non-operated patients, the mental level worsened significantly. CONCLUSIONS: Oxycephaly is a late-appearing craniosynostosis, with a high risk of ophthalmologic and mental complications. Based on the present series, the operation seemed effective in preventing these complications.

Adolescent↗
PubMed1997

[Primary hypothyroidism revealing pseudohypoparathyroidism without hypocalcemia and hyperphosphoremia].

BACKGROUND: Type la pseudohypoparathyroidism is due to a molecular defect causing Gs protein deficiency. It is responsible for multi-hormonal resistance and skeletal abnormalities. Parathyroid hormone resistance can be subtle so that the diagnosis can be difficult in patients with atypical manifestations. CASE REPORT: A 10-year-old boy was first referred for growth retardation (height standard deviation score: -2.8). He had short metacarpals, and scaphocephaly. Laboratory findings revealed an elevation of plasma TSH (8,8 microU/mL) with normal thyroid hormone levels. The investigations ruled out common causes of compensated hypothyroidism. Despite normal blood calcium and phosphate levels, parathyroid hormone was elevated to 358 pg/mL (normal values: 10-60) without renal failure, suggestive of hormonal resistance. The diagnosis of pseudohypoparathyroidism type la was confirmed by a 50% reduction of Gs activity. Melanodermia, associated with an elevation of ACTH was suggestive of ACTH resistance without MSH resistance. Moreover, skeletal radiography showed a narrow lumbar canal. CONCLUSION: Type la pseudoypoparathyroidism could be part of the etiological diagnosis of primary hypothyroidism, even in the absence of hypocalcemia and hyperphosphatemia. Similarly, skeletal abnormalities extend beyond the classical features of Albright's osteodystrophy.

Calcium↗
PubMed1997

Mutations of the TWIST gene in the Saethre-Chotzen syndrome.

Saethre-Chotzen syndrome (acrocephalo-syndactyly type III, ACS III) is an autosomal dominant craniosynostosis with brachydactyly, soft tissue syndactyly and facial dysmorphism including ptosis, facial asymmetry and prominent ear crura. ACS III has been mapped to chromosome 7p21-22. Of interest, TWIST, the human counterpart of the murine Twist gene, has been localized on chromosome 7p21 as well. The Twist gene product is a transcription factor containing a basic helix-loop-helix (b-HLH) domain, required in head mesenchyme for cranial neural tube morphogenesis in mice. The co-localisation of ACS III and TWIST prompted us to screen ACS III patients for TWIST gene mutations especially as mice heterozygous for Twist null mutations displayed skull defects and duplication of hind leg digits. Here, we report 21-bp insertions and nonsense mutations of the TWIST gene (S127X, E130X) in seven ACS III probands and describe impairment of head mesenchyme induction by TWIST as a novel pathophysiological mechanism in human craniosynostoses.

Acrocephalosyndactylia↗
PubMed1997

Aplasia of the vertex without scalp defect.

We report a case of an extremely rare craniofacial condition, which, to our knowledge, has previously been reported once only. A male infant presented with a giant congenital bone defect of the skull, in the vertex region (10 x 20 cm) and without scalp deficiency. Minimal turricephaly and moderate orbital hypertelorism were associated with slight limb abnormalities, but psychometrical assessments appeared normal. Nonsurgical treatment was initially decided upon, but spontaneous reossification was so moderate that skull reconstruction was carried out at 28 months of age because of the risk of trauma. A full-size resin cephalic skeletal reconstruction was obtained according to three-dimensional computed tomography using stereolithographic techniques. A titanium plate was customized on the resin model for ideal adaptation to the convex skull defect (8 x 16 cm). Surgery was simply performed, consisting of a preliminary undermining between the dura mater and the scalp and screwing of the custom titanium plate. The initial follow-up was uneventful.

Bone Plates↗
PubMed1997

Classification of previously unclassified cases of craniosynostosis.

Cases of craniosynostosis usually fall into well-demarcated categories: those related to a syndrome or those identified by a combination of suture involvement and morphological appearance. Between 1976 and 1995, 53 (3.6%) of 1474 cases in the craniofacial databank were assessed and designated as nonsyndromic but unclassifiable. The records and radiological studies obtained in these patients were retrospectively analyzed and comparisons were made with patients classified in the databank as having simple craniosynostoses. It proved possible to divide the formerly unclassifiable cases into two groups: those with "two-suture disease" (Group A) and a "complex" group (Group B) in which more than two sutures were affected. Group A consisted of 36 cases (68%) of patients presenting with clear evidence of simultaneous involvement of two sutures but with no progression over time to suggest a more diffuse pansynostosis. Suture involvement was as follows: 17 of 36 sagittal plus one coronal; seven of 36 sagittal and metopic; six of 36 sagittal plus one lambdoid; and six of 36 metopic plus one coronal. The only significant difference between the Group A cases and the cases of simple craniosynostoses was in the percentage requiring a second operation (24% vs. 5%, p < 0.0001). Group B consisted of 17 cases in which the patients presented at a slightly earlier age (mean 1 year) with severe morphological changes and multiple suture involvement. At the time of surgery, six of 17 patients showed large areas of lacunae within the cranial vault, making craniectomy the only option. In Group B, 10 of 17 patients displayed bilateral lambdoid plus sagittal suture involvement resulting in marked occipital recession posteriorly, whereas anteriorly in six of these 10 patients there was a massive frontal bone associated with posteriorly located coronal sutures. In contrast, there were also four patients in Group B with bilateral coronal plus metopic involvement resulting in a small frontal bone. There was a trend toward a lower intelligence quotient and a worse morphological outcome in the patients in Group B, but again the only result attaining statistical significance when compared to the databank was the rate of second operation (37.5 vs. 5%, p < 0.0001). "Two-suture synostosis" is a relatively straightforward condition and is treatable with standard craniosynostosis techniques. However, possibly as a result of surgical compromise when two sutures are involved, the rate of reoperation is far higher than in simple suture cases. In contrast, patients in the "complex" group presenting with severe multisuture involvement require a more tailor-made approach to their management that often entails a second procedure.

Analysis of Variance↗
PubMed1997

Anti-adhesive surfaces through hyaluronan coatings.

The ability to resist adhesion of proteins, bacteria, cells and tissue is an important requirement for the surfaces of medical devices. This article describes a surface-modification process that imparts anti-adhesive properties to the surfaces of biomedical materials through the covalent binding of hyaluronan. It can be applied to a wide range of materials to yield anti-adhesive surfaces on plastics, metals and ceramics.

Bacterial Adhesion↗
PubMed1997

Age-related changes in bone formation, osteoblastic cell proliferation, and differentiation during postnatal osteogenesis in human calvaria.

We have determined the age-related changes in the growth characteristics and expression of the osteoblast phenotype in human calvaria osteoblastic cells in relation with histologic indices of bone formation during postnatal calvaria osteogenesis. Histomorphometric analysis of normal calvaria samples obtained from 36 children, aged 3 to 18 months, showed an age-related decrease in the extent of bone surface covered with osteoblasts and newly synthesized collagen, demonstrating a progressive decline in bone formation during postnatal calvaria osteogenesis. Immunohistochemical analysis showed expression of type I collagen, bone sialoprotein, and osteonectin in the matrix and osteoblasts, with no apparent age-related change during postnatal calvaria osteogenesis. Cells isolated from human calvaria displayed characteristics of the osteoblast phenotype including alkaline phosphatase (ALP) activity, osteocalcin (OC) production, expression of bone matrix proteins, and responsiveness to calciotropic hormones. The growth of human calvaria osteoblastic cells was high at 3 months of age and decreased with age, as assessed by (3H)-thymidine incorporation into DNA. Thus, the age-related decrease in bone formation is associated with a decline in osteoblastic cell proliferation during human calvaria osteogenesis. In contrast, ALP activity and OC production increased with age in basal conditions and in response to 1,25(OH)2 vitamin D3, suggesting a reciprocal relationship between cell growth and expression of phenotypic markers during human postnatal osteogenesis. Finally, we found that human calvaria osteoblastic cells isolated from young individuals with high bone formation activity in vivo and high growth potential in vitro had the ability to form calcified nodular bone-like structures in vitro in the presence of ascorbic acid and beta-glycerophosphate, providing a new model to study human osteogenesis in vitro.

Age Factors↗