Dominique Renier

Management of craniosynostoses

Abstract Although it is currently thought that surgery is indicated mainly for cosmetic reasons in isolated craniosynostoses, the functional aspects of the treatment must not be underestimated. Prospective studies on intracranial pressure and mental evolution of these children have shown that there were functional consequences in a significant proportion of cases even of single suture fusion. The frequency of increased intracranial hypertension and the risk of mental impairment depend on the age of the child and the type of craniosynostosis. In nonsyndromic cases, the higher risks are observed in multisutural craniosynostoses (brachycephaly, oxycephaly). In syndromic cases, the risk of intracranial hypertension is higher in Crouzon syndrome, and Apert syndrome carries the higher risk of mental retardation. The study of a personal series of 2,137 craniosynostoses shows that the functional and the cosmetic results are better after early surgery, and that the operative risks are not higher in infants than in older children.

Congenital lumbosacral lipomas

Abstract 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 pro-phylactic 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 worse after surgery. (5) The natural history of the malformation, that is to say the risk of spontaneous aggravation, has only been evaluated in hospital in-patients, so that the true level of risk remains unknown. This means we cannot interpret the actuarial curve following surgery for asymptomatic lipoma of the conus. In conclusion, there are two different types of lipoma: lipoma of the filum, for which surgery is harmless and beneficial in both the short and the long term, and lipoma of the conus, for which surgery involves considerable risks and is of questionable benefit in the long term. This raises the question as to whether prophylactic surgery is indicated for patients with asymptomatic lipomas of the conus, and whether the outcome is any better than it would be if the lipoma were left to take its natural course. The lack of basic information remains a stumbling block to management of these patients. Until this is remedied, we are unable to recommend prophylactic surgery in patients with asymptomatic lipomas of the conus.

Intracranial Pressure and Intracranial Volume in Children with Craniosynostosis

Intracranial volume and intracranial pressure have been measured in 66 children with craniosynostosis, 48 boys and 18 girls. The premature fusion of skull sutures is assumed to restrict skull growth and predispose to elevated intracranial pressure. Thirteen children (20 percent) had raised intracranial pressure and demonstrated a significant restriction of skull growth. In this series, volume measurement alone, however, did not serve as a reliable predictor that the intracranial pressure was raised.

Genetic study of scaphocephaly.

From a series of 1,408 patients with craniosynostosis hospitalized between 1976 and 1994, 561 probands with non-syndromal isolated sagittal synostosis were analyzed. The prevalence of sagittal synostosis was estimated in the order of 1 in 5,000 children. Family information was obtained from 373 probands distributed among 366 families. The male:female ratio was 3.5:1. There was no maternal or paternal age effect. In 22 of the 366 pedigrees, a high degree of familial aggregation was observed, giving a 6% figure of familial cases. Segregation analysis of 253 families indicates that sagittal synostosis is transmitted as a dominant disorder with 38% penetrance and 72% of sporadic cases. The frequency of twinning was 4.8% with only 1 concordance for sagittal synostosis in a monozygotic twin pair. The possibility of a mechanical pathogenesis in sporadic cases is discussed.

Intellectual outcome in children with malignant tumors of the posterior fossa: influence of the field of irradiation and quality of surgery

The purpose of this study was to determine the respective parts played by cerebral hemisphere irradiation, posterior fossa irradiation, and surgery in the poor late functional results often observed in children treated for medulloblastoma. To do this we compared the intellectual outcome in a series of 59 children operated on for medulloblastoma, who had received whole-brain irradiation, to that observed in a series of 37 children operated on for ependymoma of the posterior fossa, who had received radiotherapy only on the posterior fossa. Only patients who had survived for more than 2 years without recurrence were included. At the assessment 1 year after treatment, intellectual outcome was somewhat better in the ependymoma group, but the difference was not statistically significant. At the long-term follow-ups at 5 and 10 years the results remained stable in the children treated for ependymoma, around 60% having an IQ above 90, whereas the intellectual level of the children treated for medulloblastoma was seen to have deteriorated progressively: 20% had an IQ above 90 5 years after treatment and only 10% at the 10-year followup. This progressive degradation is most likely due to the irradiation of the cerebral hemispheres, as this prophylactic irradiation constituted the only difference between the two groups. Moreover, irradiation to the posterior fossa did not seem to affect intellectual functions, since in the group of children with ependymomas the proportion of IQs above 90 was high and remained stable over the years. Surgery was certainly responsible for some poor results. The percentage of IQs above 90 observed 1–2 years after treatment was between 70 and 80 when no postoperative complications occurred, and only between 20–40% in the presence of postoperative complications. Postoperative aggravation was in most cases related to a brain-stem lesion. These results encourage the reduction, when possible, of irradiation to the cerebral hemispheres and underline the importance of the quality of surgery.

Syndromal and nonsyndromal primary trigonocephaly: Analysis of a series of 237 patients

From a series of 1,713 patients with craniosynostosis hospitalized between 1976 and 1996, 237 propositi with metopic synostosis were analyzed. The prevalence of metopic synostosis was estimated in the order of 1 in 15,000 children. Family information was obtained from 184 propositi from 179 families. The male-to-female ratio was 3.3:1. There was no maternal or paternal age effect. A family history was obtained in 10 of the 179 families, giving a 5.6% figure of familial cases. The frequency of twinning was 7.8% with two concordances for metopic synostosis in two monozygotic twin pairs. The male-to-female ratio, the twinning frequency, and the proportion of familial cases in trigonocephaly are very similar to those observed in scaphocephaly, which also involves the longitudinal sutural system. Fetal exposure to valproic acid was noticed in eight cases. The series was divided into two groups: nonsyndromal trigonocephaly (n = 184) and trigonocephaly associated with other malformations (n = 53). The second group included 13 cases of well-delineated syndromes and 40 cases of trigonocephaly associated with one or more malformations, but without any known syndrome, that could be undelineated syndromes. These groups differed significantly in their mental prognosis.

Chiari malformation in craniosynostosis

IntroductionChiari malformation (CM) is a frequent finding in multisutural and syndromic craniosynostosis, occurring in 70% of patients with Crouzon’s syndrome, 75% with oxycephaly, 50% with Pfeiffer’s syndrome and 100% with the Kleeblattschädel deformity. The pathogenesis of this condition and rationale for treatment are still controversial.DiscussionSince its first description in 1972, several factors have been cited to play a role in inducing CM. In the light of recent publications, the roles of premature fusion of cranial vault and cranial base sutures, of congenital anomalies of the cerebellum and brain stem, of raised intracranial pressure, of venous hypertension and of hydrocephalus are reviewed. Evaluation and management of CM are also discussed.ConclusionChiari malformation appears to be an acquired and progressive condition that develops in the first months of life, because of a disproportion between hindbrain growth and an abnormally small posterior fossa, a consequence of the premature fusion of lambdoid and cranial base sutures. Venous hypertension caused by stenosis of the jugular foramen can also be present in these patients, resulting in intracranial hypertension and/or hydrocephalus. Careful MRI evaluation is recommended for the forms of craniosynostosis at a high risk of developing hindbrain herniation. The selection of posterior cranial vault expansion as the first surgical procedure is advocated. In selected cases, treatment of the posterior cranial deformity by occipital vault remodelling and treatment of the Chiari-like deformity by suboccipital decompression can be carried out using the same surgical procedure.

Epidemiology and early predictive factors of mortality and outcome in children with traumatic severe brain injury: experience of a French pediatric trauma center.

Objective: To describe the results of an integrated pre- and in-hospital approach to critical care in a large population of children with severe traumatic brain injury and to identify the early predictors of their outcome. Design: A 9-yr retrospective review of the data of a trauma data bank. Setting: Level III pediatric trauma center. Patients: All children (1 month to 15 yrs) with severe traumatic brain injury (Glasgow Coma Scale ≤8) hospitalized in our trauma center and followed until death or for ≥6 months after discharge. Interventions: None. Measurements and Main Results: Univariate and further multivariate analyses were performed to determine independent predictive factors of death and outcome at discharge and 6 months later. The Glasgow Outcome Scale was used to evaluate outcome; a poor outcome referred to Glasgow Outcome Scale ≥3. Receiver operating characteristic curves were drawn to determine the threshold values of predictors of death and outcome. Analysis concerned 585 children (67% male and 33% female). Mean age was 7 ± 5 yrs. Predominant mechanisms of injury were road traffic accidents and falls. Mean values for Glasgow Coma Scale, Pediatric Trauma Score, and Injury Severity Score were 6 (3–8), 3 (−4,10), and 28 (4–75), respectively. Mortality rate was 22%; Glasgow Outcome Scale was <3 in 53% of the cases at discharge and 60% at 6 months. Multivariate analysis identified Glasgow Coma Scale, Injury Severity Score, and hypotension on arrival as independent predictors of death and poor outcome at discharge and at 6 months. Threshold values for death were 28 for Injury Severity Score and 5 for Glasgow Coma Scale. The same values were found for poor outcome, except for outcome at 6 months where threshold value for the Glasgow Coma Scale was 6. Conclusions: Initial hypotension, Glasgow Coma Scale, and Injury Severity Score are independent predictors of outcome in children with traumatic brain injury. Threshold values can be calculated for predicting poor outcome. These variables can be easily and detected early in this population and used for quality assessment.

Timing of treatment for craniosynostosis and faciocraniosynostosis: a 20-year experience

Abstract The timing of surgery for craniosynostosis is still controversial. Having used the same basic techniques since 1973, and having done follow-up on the growth of our 983 operated patients, we thought it useful to report our protocol. Early frontocranial remodelling is performed between 2 and 4 months for brachycephalies, but the other craniosynostoses are operated on between 6 and 12 months of age. When diagnosis is made later, we perform the same operations until 4 years of age, with some modifications, such as a tongue in groove advancement for brachycephalies, and a complete closure of the bony defects after 2 years of age. Later on, facial distortion and frontal sinus development complicate the surgery. For syndromal craniofacial synostosis, we prefer to perform a two-step operation: forehead advancement first, facial advancement later, to avoid the risk of frontal osteitis. The frontofacial monobloc is indicated, in our opinion, for severe exorbitism in infancy but otherwise we prefer a two-stage procedure. Facial bipartition is necessary to narrow the upper face and widen the maxilla in Aperts syndrome.

Medulloblastoma in childhood: progressive intellectual deterioration.

A series of 120 medulloblastomas in children operated on between 1967 and 1987 at the Hôpital des Enfants-Malades has been reviewed in order to check whether the conclusions of our study published 10 years ago have remained valid and, in particular, to verify whether the quality of life of these patients, which had been found to be poor at the time, had improved or worsened over the years. The postoperative mortality for the whole series was 6.5% there have been no deaths in the 35 patients operated on after 1980. The overall survival rate for the 120 children was 60% at 5 years and 53% at 10 years; for the patients who completed radiotherapy, the survival rates was 73% at 5 years and 64% at 10 years. Survival rates were surprisingly better in patients treated when under 6 years of age than in older children. They were also better in girls than in boys, and in desmoplastic compared with other medulloblastomas; however, the differences were not significant. When comparing the groups after total or subtotal resection of tumors, survival rates were not significantly different, but were lower in the small group of partial resections. Cell differentiation did not influence the prognosis. Psychological sequelae were significant and worsened over the years. Five years after treatment 58% of the children showed an IQ above 80; 5 years later this group included only 15% of the patients. These psychological sequelae were related to age at the time of radiotherapy: the younger the child, the lower the final IQ. Five years after treatment, 40% of the children had a normal academic level; 5 years later this group was reduced to 11%. Ten years after treatment, 36% of the patients were unempolyed and 64% worked in a protected environment. No patient had normal employment. These disastrous results concerning the quality of life of these medulloblastoma patients justify new trials with reduced doses of irradiation over the hemispheres, at least in low-risk groups.