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John C Wellons

Publications and source records attributed to John C Wellons.

At least 55 records · Page 3Linked to original sources
PubMed2004

Cessation of chronic hypertension after posterior fossa decompression in a child with Chiari I malformation. Case report.

The authors report on the case of a patient evaluated for Valsalva maneuver-induced headache, dizziness, and ataxia. Neuroimaging revealed a Chiari I malformation without syringomyelia. A history of idiopathic hypertension was noted. After posterior fossa decompression, pathologically elevated blood pressure was absent, and at 24-month follow-up evaluation the patient remained normotensive. Although seemingly rare, this case illustrates that some patients with tonsillar ectopia may exhibit elevated blood pressure. Clinicians should consider hindbrain herniation a rare cause in idiopathic hypertension.

Adolescent↗
PubMed2004

Neuroendoscopic findings in patients with intracranial germinomas correlating with diabetes insipidus.

OBJECT: Intracranial germinomas commonly occur in the pineal region, the floor of the third ventricle (hypothalamus), or both, and they are often associated with diabetes insipidus (DI). The authors conducted a study to correlate preoperative DI with the endoscopic and magnetic resonance (MR) imaging evidence of tumor on the third ventricle floor. METHODS: The authors reviewed hospital records, office charts, and MR imaging studies obtained in patients in whom a biopsy sampling procedure was performed with or without endoscopic third ventriculostomy (ETV) at Children's Hospital, Birmingham, Alabama between May 1998 and July 2002. Ten patients with the pathological diagnosis of pure germinoma were identified. Preoperative MR imaging findings and presenting symptoms were correlated with intraoperative neuroendoscopic findings. Seven patients presented with symptomatic hydrocephalus and underwent concomitant ETV. Six patients presented with DI and MR imaging evidence of involvement of the third ventricle floor. Two patients presented with DI and no initial MR imaging evidence of neoplastic involvement of the third ventricle floor; in both there was endoscopic evidence of neoplastic involvement of the floor of the third ventricle. In two children without DI, neither MR imaging nor endoscopic evidence of involvement of the third ventricle floor was observed. CONCLUSIONS: In the authors' experience with intracranial germinoma, endoscopic tumor biopsy sampling, and ETV provide an effective, safe, and minimally invasive means of obtaining diagnostic tissue and treating any concomitant hydrocephalus. The authors found that preoperative DI is an absolute predictor of neoplastic involvement of the hypothalamus regardless of MR imaging findings. Therefore, in the setting of DI and intracranial germinoma without neuroimaging evidence of hypothalamic involvement, germinomatous involvement of the hypothalamus should be assumed present, if not confirmed endoscopically at the time of biopsy sampling or third ventriculostomy, when devising adjuvant treatment plans for such patients.

Adolescent↗
PubMed2004

Arachnoid veils and the Chiari I malformation.

OBJECT: The literature contains scant data regarding variations in anatomy at the level of the foramen of Magendie in patients with Chiari I malformation and syringomyelia. METHODS: Based on their operative experience and hospital data, the authors detailed the incidence of arachnoid veils found in juxtaposition to the foramen of Magendie in patients with hindbrain herniation. Additionally, radiological studies were retrospectively reviewed in cases in which such an anomaly was noted intraoperatively. Of 140 patients with Chiari I malformation who underwent decompressive surgery, an associated syrinx was demonstrated in 80 (57%). The foramen of Magendie was obstructed by an arachnoid veil in 10 (12.5%) of these patients; once the lesion was punctured, the cerebrospinal fluid drained freely from this median aperture. On retrospective review of imaging studies, none of these anomalous structures was evident. In all patients with an arachnoid veil and syringomyelia resolution of syringomyelia was revealed on postoperative imaging. CONCLUSIONS: In the absence of a clear pathophysiology of syrinx production, the authors would recommend that patients with syringomyelia and Chiari I malformation undergo duraplasty so that, if present, these veils can be fenestrated.

Adolescent↗
PubMed2003

Split cord malformation and situs inversus totalis: case report and review of the literature.

INTRODUCTION: Situs inversus is a rare condition of visceral transposition in which the spinal axis is rarely affected. CASE REPORT: The authors report a patient with situs inversus totalis and type II split cord malformation. This patient had no complaints and presented with scoliosis. CONCLUSIONS: Recent compelling evidence from animal models and human case reports has led to hypotheses that defects of the midline and laterality defects (e.g., situs inversus) are etiologically related. Confirmation from additional case reports of situs inversus and split cord malformation could prove useful in determining a genetic locus for split cord malformations or implicating various chemical agents that are known to produce situs inversus as potential causative factors in the production of split cord malformations.

Child↗
PubMed2003

Intracranial anatomic asymmetry in situs inversus totalis.

Situs inversus is a rare condition in which the position of the thoracic and the abdominal viscera are exchanged from the left to the right sides. A possible inversion of normal dominant intracranial anatomy, has however, rarely been discussed. We examine here the gross anatomy of an elderly cadaveric female for a possible "situs inversus" of the intracranial contents. This study has found that many structures commonly dominant on one side in the intracranial compartment were reversed in this specimen. These findings support the concept that a reversal of more commonly found intracranial anatomy may occur in situs inversus totalis, and this should alert the clinician performing invasive procedures in this population. These data will also hopefully provide further insight into possible mechanisms that contribute to situs inversus totalis.

Aged↗
PubMed2003

Cranial deformation.

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Craniofacial Abnormalities↗
PubMed2003

Cutaneous manifestations and the Chiari I malformation.

This article presents a child with Chiari I malformation and cutis marmorata telangiectatica congenita and reviews the medical literature regarding Chiari I malformation and other cutaneous disorders. In addition to cutis marmorata telangiectatica congenita and Chiari I malformation, our patient exhibited hemihypertrophy, Tourette's syndrome, scoliosis, obsessive-compulsive disorder, and seizures. Other associated findings seen in patients with Chiari I malformation include basilar invagination, Klippel-Feil syndrome, atlantoaxial assimilation, scoliosis from an underlying syrinx, and hydrocephalus.

Arnold-Chiari Malformation↗
PubMed2003

Chorda dorsalis.

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Child↗
PubMed2003

Comparison of total versus partial revision of initial ventriculoperitoneal shunt failures.

BACKGROUND: Optimal surgical management of patients presenting with shunt failure in the age of neuroendoscopy remains complex. The value of replacing the entire shunt system as opposed to a single shunt component has not been assessed. METHODS: We reviewed the records of all pediatric patients who underwent their first shunt revision between January 1992 and December 1998. Patients with primary shunt failure attributed solely to proximal catheter obstruction or distal catheter obstruction were included for analysis. Shunt revisions were classified as total (entire shunt replaced) or partial (only malfunctioning component replaced). Kaplan-Meier (shunt survival curves) and log rank analysis were used to compare failure rates between partially and totally revised shunts according to the underlying diagnosis and failed shunt part. Significant differences in univariate analysis were confirmed with a multivariate proportional hazards regression model. RESULTS: 301 pediatric patients underwent primary shunt revision (183 total, 118 partial revisions). All shunts utilized distal slit peritoneal catheters. In shunt failures attributed to proximal obstruction, reutilization of the distal catheter was associated with a 57% increased risk of subsequent shunt failure (hazard ratio 1.57, 95% confidence interval 1.19-3.49). In shunt failures attributed to distal obstruction, subsequent shunt survival was not affected by reutilization of the proximal catheter (p = 0.581). When stratified according to the etiology of hydrocephalus, only patients with intraventricular hemorrhage (IVH) failed to demonstrate greater survival of totally revised shunts. CONCLUSIONS: In this series, in the setting of proximal shunt catheter obstruction, reutilizing the functional distal catheter was associated with an increase in subsequent shunt failure rates compared to revising the entire shunt system. Total revision was not associated with improved shunt survival in patients with IVH.

Adolescent↗
PubMed2003

Reformation of the posterior atlanto-occipital membrane following posterior fossa decompression with subsequent constriction at the craniocervical junction.

The posterior atlanto-occipital membrane (PAO) contributes little to craniocervical stability and is generally underappreciated and incised with most suboccipital craniectomies. We report a case of a child who underwent posterior fossa decompression for Chiari I malformation with syringomyelia whose symptoms had not resolved months after surgery. A secondary exploratory operation revealed a healed constricting PAO which had been incised linearly at the initial operation. This patient's symptoms improved soon after the second surgery. We propose that attention be given to this membrane, and if it is incised with underlying dura mater as in a standard posterior fossa decompression, it should be removed or cauterized separately and laterally to inhibit its reformation.

Arnold-Chiari Malformation↗
PubMed2003

Hemihypertrophy and the Chiari I malformation.

We report two children with hemihypertrophy and Chiari I malformation (CIM) and review the extant medical literature regarding CIM and overgrowth disorders. We propose that these two entities do not represent a spurious association but rather share a common dysembryology of mesoderm.

Arnold-Chiari Malformation↗
PubMed2003

Life expectancy of ventriculosubgaleal shunt revisions.

The subgaleal shunt has been and is currently used for the temporary bypass of the normal cerebrospinal fluid (CSF) pathways. We retrospectively reviewed all subgaleal shunts placed at the Children's Hospital, Birmingham, Ala., USA, from 1993 to the present and examined the life expectancy of revisions of this temporary method of CSF diversion. The average length of survival of primary, secondary and tertiary subgaleal shunts in this population was 37.4, 32.4 and 19.6 days, respectively. This current review demonstrates that the majority of patients in whom a subgaleal shunt is utilized may continue to obtain therapeutic diversion of their CSF for greater than 2.5 months with intermittent subgaleal shunt revisions. In the majority of cases, this length of time is sufficient to manage and resolve issues that would make ventriculoperitoneal shunting undesirable.

Adolescent↗
PubMed2003

Children with growth hormone deficiency and Chiari I malformation: a morphometric analysis of the posterior cranial fossa.

OBJECTIVE: The posterior fossa (PF) has been found to be small in various forms of Chiari malformation. Explanations involving a connection between growth hormone deficiency (GHD) and Chiari I malformation (CIM) have been proposed. However, to date, no quantitative analysis of the PF of patients with CIM and GHD has been performed. Our study was performed to determine the geometry of the PF in children with GHD and CIM. METHODS: Morphometric analysis of the PF was performed in 10 children with GHD and CIM (group 1), 20 children with GHD and no CIM (group 2) and 50 controls. RESULTS: PF volumes for group 1 ranged from 128 to 259 +/- 33 ml, and for group 2, they ranged from 115 to 186.2 +/- 25.4 ml. Lengths of the foramen magnum for groups 1 and 2 had means of 36 and 38 mm, respectively. The mean basiocciput length and tentorial angle for groups 1 and 2 were 20 and 19 mm and 89 and 87.5 degrees, respectively. CONCLUSIONS: We have determined that children with GHD with or without CIM have no significant difference in their PF volume compared to controls. However, our data demonstrate significant underdevelopment of portions of the bony PF in both patients with GHD alone and in patients with GHD and CIM. Tentorial angles were elevated in noncontrol groups. We propose that this association is not due to an increased rate of 'midline' defects seen in GHD but rather a structurally distorted PF that is not capacious enough to house the entire developing rhombencephalon. These data will hopefully aid in the further understanding of the pathophysiology of CIM.

Adolescent↗
PubMed2003

Alternative uses for the subgaleal shunt in pediatric neurosurgery.

The subgaleal shunt has been used for the temporary bypass of the normal cerebrospinal fluid (CSF) pathways. We retrospectively reviewed all subgaleal shunts placed at the Children's Hospital, Birmingham, Ala., USA, from 1997 to the present and examined all uses (e.g. indication, length of follow-up) of the subgaleal shunt outside its use for temporary CSF diversion in premature infants with intraventricular hemorrhage and subsequent hydrocephalus. The average length of survival of the primary subgaleal shunt in this population was 32.2 days. We have had good success with subgaleal shunts in children with malignant brain tumors, intraventricular abscesses, chronic truncal wounds, chronic subdural hygromas and meningitis. However, the greatest utility has been in those scenarios in which the peritoneal cavities were not currently, but with time would be, candidates for distal shunt implantation. Examples of these instances are patients with hydrocephalus and necrotizing enterocolitis or hydrocephalus and preoperative abdominal wall pathology such as omphalocele.

Brain Diseases↗
PubMed2003

Ectopic brain tissue in a neonate.

We report a 2-week-old male with a large cystic mass in the left cervical and face region. No connection to the brain or spinal cord was discernable either at operation or on imaging. Histological study of this mass revealed central nervous tissue including neuroglia, ependymal cells, non-neuroblastic neurons, pigmented retinal epithelium, and choroid plexus. This case represents the rare ectopic 'brain'. We review this case as well as the literature concerning these unusual masses.

Brain↗
PubMed2003

Endoscopic third ventriculostomy for hydrocephalus secondary to central nervous system infection or intraventricular hemorrhage in children.

OBJECTIVE: We review our experience of endoscopic third ventriculocisternostomy (ETV) in children with hydrocephalus from central nervous system (CNS) infection or intraventricular hemorrhage to better elucidate success rates and predictors of success in these children. METHODS: We performed a retrospective review of 12 children less than 21 years of age with ETV treated from 1999 to 2002 with a minimum follow-up of 12 months. Children selected for surgery had been diagnosed with hydrocephalus from perinatal germinal matrix hemorrhage or CNS infection and had neuroimaging consistent with obstruction of the aqueduct, fourth ventricular outlets or both at the time of ETV. Charts and imaging studies were reviewed to determine clinical outcomes and predictors of successful ETV. An ETV was deemed successful if the child did not require placement or replacement of a ventriculoperitoneal shunt. RESULTS: Thirteen ETV were performed in 12 patients (7 boys and 5 girls; mean age 9.2 years, range 3.8-21 years), with an overall success rate of 60% for those with CNS infections and 71% for those with perinatal intraventricular hemorrhage at initial presentation. There were no significant complications from the procedure. CONCLUSIONS: ETV is a safe procedure, which in carefully selected children with etiologies of hydrocephalus thought to be 'communicating' in nature carries a satisfyingly high success rate. Further application and study of this modality in larger groups of patients with these causes of hydrocephalus is warranted.

Adolescent↗
PubMed2003

Suprasellar lymphoid hyperplasia presenting with diabetes insipidus and hypogonadism.

We report a pediatric patient who presented with hypogonadism and diabetes insipidus. Further evaluation revealed hypothyroidism. MRI of the brain revealed a suprasellar mass. Following frontal craniotomy for mass biopsy, histological analysis of the mass revealed benign lymphoid hyperplasia. The patient has had no progression of his mass or symptoms at most recent follow-up (10 months). We review this unusual case and other similar conditions. We believe this to be the first reported case of lymphoid hyperplasia without malignant cells of the suprasellar region.

Adolescent↗